1. ??? ?? ?? ??

Cryogenic treatment usually adopts liquid nitrogen cooling, which can cool the workpiece to below – 190 ℃. The microstructure of the treated material changes at low temperature, and some properties are improved. Cryogenic treatment was first proposed by the former Soviet Union in 1939. It was not until the 1960s that the United States applied the cryogenic treatment technology to the industry and began to use it mainly in the aviation field. In the 1970s, it expanded to the machinery manufacturing field.

?? ??? ?? ?? ??? ?? ???? ?? ? ????. ?? ??? ?? ?? ???? ?? ??? ?? ???? ???? ?? ?? ??? ????? ???? ?? ?? ??? ???? ?? ? ?? ??? ?? ??? ???? ?? ?????. . ?? ?? ?? ?? ? ?? ??? ???? ?? ????, ?? ??? ?? ?? ??? ?? ????? ??? ??? ? ???? ??? ????. ??? ??? ?? ?? ??? ?? ??? ?????.

2. ??? ??? ?? ??

The gas principle is to cool by the gasification latent heat of liquid nitrogen (about 199.54kJ/kg) and the heat absorption of low-temperature nitrogen. The gas method can make the cryogenic temperature reach – 190 ℃, so that the cryogenic nitrogen can contact the materials. Through convection heat exchange, the nitrogen can be vaporized in the cryogenic box after being ejected from the nozzle. The workpiece can be cooled by the latent heat of gasification and the heat absorption of cryogenic nitrogen. By controlling the input of liquid nitrogen to control the cooling rate, the cryogenic treatment temperature can be automatically adjusted and accurately controlled, and the thermal shock effect is small, so is the possibility of cracking.

?? ?? ??? ?? ???? ????? ?? ?? ???? ??? ?? ??? ?? ??? ??? ? ?? ????? ??? ??? ?????. ??? ??? ??? ??? ??? ?? ??? ?? ? ??, ?? ??, ?? ?? ? ?? ??? ??, ???? ? ?? ???? ?? ???? ? ????.

????? ??? ??? 1980??? 1990??? ?? ???????. ?? ?? 1981? ??? ?? ?? ?? 1992? ???? ??? ?? ? ????? ??? ?? ?????? ??????. 1970?? ?? ???? ??? ??? ?? ??? ??? ???. ???, ??, ?? ? ?? ????? ??? ??? ????? ???? ?? ? ??? ??, ???? ???? ? ?? ???? ??????.

3. ??? ?? ???? ??

?? ? ??.

????? Co? fcc ?? ?? α?(fcc)? ??? ??? ?? ?? ε?(hcp)? ??? ????. ε- Co ?? α- Co? ?? ??? ?? ????? ????. 417 ℃ ?? α ?? ?? ???? ?? Co α ? ??? ????. 417 ℃ ?? ε ?? ?? ?? ???, ???? ??? ? α ?? ?? ????? ? ?? ε ?. ??? WC ??? α? ?? ? ?? ??? ?????? ??? ???? ? ? ??? ?? α → ε ??? ??? ???? ??? 417℃ ??? ???? α ?? ??? ??? ? ?? ε ???. ??? ??? α ? ε 2?? ?? ??? ??? ?? ???? ? ???? ? ??? ???? ??????. ε ? ?? ??. ??? ?? ? ????? ??, Co? ??? ?? ??? ??? ??? ?? ??? ??? ????, ?? Co ????? ???? ????? ?? ??? ???? 2??? ????? ??? ? ? ????. ??.

?? ???? ??.

??? ?? ?? ??? ?? ?? ?? ??? ???? ?????. ?? ????? ???? ?? ?? ??? ?? ?? ??? ??? ?? ???? ? ??? ????. ?? ? ????? ?? ???? ??? Co? ?? ??? ?? WC ??? ?? ??? ????. ?? ??? Co? ? ??? ???. ??? ?? ????? ????? ?? ?? ?? ??? ??? ?? ? ?? ???? ?? ??? ?? ??? ?? ??? ???? ????? ????? ??? ?? ?????? ??? ????. ?? ??, ?? ?? ?? ??.

?? ?? ????

η ? ??? WC ??? ?? ????? ?? ???? ???? ??? η? ?? ?? ??? ?????? Co? ????? ?????. ?? ???? Co ??? ??? ??? ?? ????? ????? ??? ?? ?? ? ???? ??? ?? ????? ????? ??????. ????? ??? ?? ?? ? ?? ?? ??? ? ?????. ?? ? ??? ???? ? ?? ??? ?????. ?? ???? ??? ?? ? Co? ?? ? ???? ?? WC ??? ???? Co? ??? ??? ????? ????. ?????? ?? ??? ??? ?? ??? ??? ?????? ????.

4. ??? ??? YG20 Cold Heading Die? ??

YG20 ?? ?? ??? ??? ??? ?? ??:

(1) ??? ?? ?? ??? ??? ???? ????.

(2) Start the cryogenic tempering integrated furnace, open the liquid nitrogen, reduce it to – 60 ℃ at a certain rate, and keep the temperature for 1h;

(3) Reduce to – 120 ℃ at a certain rate, and keep the temperature for 2h;

(4) Reduce the temperature to – 190 ℃ at a certain cooling rate, and keep the temperature for 4-8h;

(5) ?? ? 180℃?? 0.5℃/min?? 4?? ????.

(6) ???? ??? ???? ???? ??? ??? ???? ?? ?????.

??: ??? ??? ?? ?? YG20 ???? ??? ??? ?? ? Φ 3.8 ??? ??? ??? ????? ??, ??? ?? ? ??? ??? ??? ??? ?? ?? ???? 15% ?? ? ? ??? ??????. .

??? ?? ?? ???? ??? ?? ? YG20? ?? ?? ???(fcc)? ??? ???? ? ? ???, ε- Co(hcp)? ??? ??? ???? ??? ????, ????? ???? ??.

5. ??? ?? ??? ??

?? ?? ? ?? ??? ?? ?? ??? ??? ?? ??? ?? ? ??? 2~8? ???? ?? ?? ? ?? ?? ??? ??? ??? ??? ??? ? ??? ?????. ? ????. 1990???? ????? ??? ??? ?? ?? ??? ???? ??? ????? ?????.

????? ????? ??? ?? ??? ?? ??? ?? ? ???? ?? ????? ???, ?? ??? ???? ?? ???? ??? ? ??? ?????. ?? ?? ???? ??? ??? ??? ?? ????? ????? ??? ????? ??? ???? ??? ??? ??? ????.

Edge radius processing is an indispensable process after fine grinding of CNC tools and before coating. The purpose is to make the cutting edge smooth and smooth, and extend the tool life. There are 9 methods of edge radius treatment of CNC tools introduced by Meetyou. Let’s get to know it.

Edge radius?treatment of the cutting tools of the machining center refers to the process of leveling, polishing and deburring the cutting tools, including edge passivation, chip removal groove polishing and coating polishing.

1. Resistance to tool physical wear

In the cutting process, the tool surface will be gradually consumed by the workpiece, and the cutting edge is prone to plastic deformation under high temperature and high pressure. The passivation treatment of tools can help improve the rigidity of tools and avoid premature loss of cutting performance of tools.

2. Maintain the smoothness of the workpiece

Burrs on the cutting edge of the tool will cause tool wear, and the surface of the machined workpiece will become rough. After passivation treatment, the cutting edge of the tool will become very smooth, the phenomenon of edge collapse will be reduced accordingly, and the surface finish of the workpiece will also be improved.

3. Convenient groove chip removal

Polishing the tool groove can improve the surface quality and chip removal performance. The smoother the groove surface, the better chip removal will be, and more consistent cutting can be achieved.

After passivation and polishing, the tools of CNC machine tools will leave many small holes on the surface. These holes can absorb more cutting fluid during machining, which will greatly reduce the heat generated during cutting and greatly improve the cutting speed.

9 kinds of edge radius processing methods

Grinding wheel edge radius?method

This is the earliest and most widely used passivation technology.

Nylon brush?edge radius?method

it is a common method to coat the abrasive medium of fine particles on the brush wheel or brush disc of nylon material, and re move the cutter through the high-speed rotation of the brush.

Sand blasting method

it is divided into dry sand blasting and wet sand blasting. It is also a common method of edge radius processing. Compared with nylon brush method, this process accomplish?a higher consistency of edges.

Stirring method of edge radius processing

This method is to put the whole tool into the abrasive bucket before treatment, and position the depth of the tool through the laser sensor to ensure the quality of treatment. The blade consistency of this process is also higher than that of nylon brush method.

Electrochemical mechanical edge radius processing

This is a composite process that combines electrochemical machining and mechanical grinding. First, electrolytic deburring, and then mechanical grinding to remove oxide film.

Laser method: it is a passivation technology developed on the basis of laser cladding technology. It can produce high heat on the blade surface by laser, melt some materials, and achieve the effect of passivating the blade.

Vibration edge radius processing method

 the main processing device includes a vibration table and a worktable. The blade is placed in a container that is connected with the vibration body. The container is filled with abrasive particles. The abrasive particles and the blade repeatedly collide to remove trace materials on the cutting edge through collision to achieve edge passivation.

Magnetic abrasive method

This is a edge radius processing that applies a magnetic field in the direction perpendicular to the axis of the cylindrical surface of the workpiece, and adds magnetic abrasive between the magnetic field S and N poles. The magnetic abrasive will be adsorbed on the magnetic pole and the workpiece surface, and will be arranged into a flexible “abrasive brush” along the direction of the magnetic line of force. The cutter rotates and vibrates axially at the same time to remove the metal and burrs on the workpiece surface.

Micro abrasive water jet technology: a new and environment-friendly processing technology, which forms a liquid-solid high-energy jet through the control of the pressurizer and nozzle diameter, and realizes passivation treatment by high-speed and repeated collision on the workpiece.

??? ??? ?? ??, ??? ?? ?? ?? ??? ?? ??? ???? ?? ??? ???? ?????. ???? ?? ?? ??? ??? ????? ?????. ???? ?? ???? ?? ??? ??? ????? ?? ?? ??? ?? ?? ?? ????.

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??? ????? ??? ?? ??? ?? ?? ???? ??, ??, ?? ? ?? ???? ?? ? ?? ?? ??? ???? ???? ?? ??, ??? ???? ?? ????. ??, ?? ?? ?? ????. ??, ???? ?? ??? ?? ???? ???? ? ?? ???????. ???? ???? ?? ?? ?? ??? ??? ?? ?????. ???? ?? ? ?? ??? ??? ?? ?? ??? ??, ??, ?? ?? ? ??? ?? ??? ?? ?? ??? ?? ?? ?? ?? ??? ?? ???????.

?? ??? ??

?? ??:

?? ??? ???? ??? ?? ??? ???? ?? ??? ???? ???? ????? ??? ?? ?? ??? ?? ??? ?? ?? ??? ??? ???? Etching? ?? Wet Etching ? ?? ?? ???? ?? ??? ???? ?? ??? ? ??? ??? ???? ?? ??? ?? ??? ??? ?????. ?? ?? ??? ??? ?? ?? ?? ??? ???? ???? ?? ???? ?? ??? ?????. ?? ??? ?? ???? ??? ?? ??? ?? ?? ??? ????.

?? ??:

?? ??? ????? ???? ?? ?? ??? ?? ? ?????. ?? ??? ??? ??? ???? ??? ??? ??, ?? ?? ???? ?? ?? ? ??(???)? ?? ?? ?? ? ?? ???? ?? ??? ?????.

??? ??: ???? ??, ?? ? ??

??? ??: ???? ??

????? ?? ??: ??? ?? ??(RIE)

Dry etching is a kind of anisotropic etching, which has good directivity, but the selectivity is worse than wet etching. In plasma etching, plasma is a partially dissociated gas, and gas molecules are dissociated into electrons, ions and other substances with high chemical activity. The biggest advantage of dry etching is “anisotropic etching”. However, the selectivity of dry etching is lower than that of wet etching. This is because the etching mechanism of dry etching is physical interaction; Therefore, the impact of ions can remove not only the etching film, but also the photoresist mask.

?? ??

??? ??? ?? ?? ??? ?????? ???? ?? ??? ?? ??? → ?? ? ?? → ?? → ?? → ?? ?? ?? ????? ?? ?? → ?? → ?? ??? → ?? → ? ?? ? ?? → ?? → ?? ?? → ?? → ?? → ??? ??.

1. ?? ?? ? ?? ??:

????? ???? ?? ??? ???? ?? ??? ?? ???? ?? ?? ??? ??, ??, ?? ?? ?? ???? ? ?????. ?? ??? ?? ?? ?? ??? ?? ??? ?? ??? ? ????? ?? ?????. ??? Metal Etching ??? Oil Stain? ???? ??? ???? ???. ?? ??? ???? ?? ??? ?? ?????. ?? ??? ???? ?? ?? ?? ?? ?? ??? ?? ??? ???? ?? ?? ????. ??? ?? ??? ??? ???? ?? ??? ???? ???? ??? ???? ???? ???. ??? ?? ?? ???? ???. ??? ?? ??.

2. ?? ?? ?? ?? ??? ??? ??? ?? ?? ????.

?? ??? ??, ??, ??? ??? ?? ?? ??? ?? ?? ?? ?? ?? ??? ??? ????? ?????. ??? ?? ??? ?? ?? ???? ??? ?? ?? ?? ?? ??? ???? ???? ???? ???. ?? ??? ?? ??? ??? ??? ???? ??? ???? ? ???? ? ?? ??? ??? ?? ?? ? ????.

3. ??:

?? ?? ???? ?? ?? ?? ? ??? ???? ??? ???? ?? ??? ???? ???. ??? ??? ???? ???, ??? ?? ??? ??????.

4. ??:

? ??? Metal Etching? ??? ???? ?? ??? ??? ???? ?? ?? ???? ???? ???. ??? ?? ?? ??? ???? ?????. ?? ??? ??? ? ?? ?? ?? ??? ? ?? ?? ??? ??? ? ??? ??? ?????.

5. ??:

?? ??? ??? ??? ???? ???? ? ?? ???? ?? ? ?????. ??? ??? ???? ??, ? ??? ??? ??? ?????. ?? ????? ?? ??? ?? ??? ?? ??? ??? ? ??? ??? ?????. ? ??? ??? ???? ??? ??? ?? ??? ?????.

6. ?? ?? ?? ??:

?? ?? ?? ??? ??? ? ??? ?????. ? ????? ?? ??? ???? ??? ?????. ? ?????? ?? ?? ??, ??, ??, ?? ? ?? ????? ?????. ??? ??? ??? ????? ?? ????? ???.

7. ??:

??? ??? ??? ??? ??? ??? ??? ?? ??? ??? ?? ??? ??? ??? ?? ???? ???. ??? ????? ???? ??? ??? ?-?? ???? ?? ????. ???? ?? ? ??? ?? ? ??? ??? ??? ?? ???? ??? ??? ???? ??????.

8. ???:

??? ?? ? ??? ???, ?? ? ?? ??? ??? ????? ???? ????.

?? ?? ? ????

?? ?? ? ?? ????? ??? ?? ?? ?? ??? ??????. ????? ?? ??? ?? ?? ??? ?? ???? ?? ??? ? ??????. ???? ??? ???? ???? ??? ??? ??? ??? ???? ?? ???? ??? ????. ???? ??? ???? ?? ??? ?????. ?? ??? ??? ?? ?? ?? ??? ? ?? ??? ?? ?? ???? ??? ???? ?? ?????. ?? ????? ?? ? ??, ??, ?? ?? ?? ?? ???? ??? ???? ???? ??? ????? ??? ???? ?????. ???? ????? ??? ?? ??? ??? ? ?? ??? ?? ???? ?????.

???? ? ?? ?? ??? ??? ??: ?? ???? ???? ?? ?? ?? ??? ????? ? ??? ?? ????? ?? ? ????. Pre Etching ???? ??? Etching ??? ???? ???? ?? ? ??? ???? Etching Rate ??? ??? Etching ??? ???? ?? ????. ??? ?? ??? ???? ??? ??? ????? ???? ??? ? ?? ??? ??? ??????. ??? ??? ?, pH ?, ?? ??, ??, ?? ??? ??? ?? ???? ??? ? ????.

?? ???? ??? ?? ?? ?? ??? ??? ??: ????? ??? ? ???? ??? ? ??? ?? ???? ?? ?? ??? ??? ???? ?? ?????. ? ??. ?? ???? ??? ??? ?? ??? ?? ???? ????. ?? ??? ?? ??? ?? ???? ????. ?? ??? ?? ???? ?? ?? ??? ?????. ???? ???? ??? ?? ??? ????? ???? ??? ? ??. ???? ???? ?? ??? ???? ??? ????? ???? ??? ??? ??? ?? ??? ???? ?? ???? ? ????.

?? ??? ??

?? ?? ??? ?? ??? ?? ???? ?????.

???? ?? ???? ??????. ??? ??, ??, ??, ?? ??, ?? ?? ? ??? ???? ????. ?? ?? ??? ??? ??? ???? ???? ??? ??? ??? ????.

?? ????. ?? ?? ???? ?? ??? ???? ??? ??, ?? ? ?? ??? ????.

??? ???? ???? ???? ??? ??? ? ?? ??? ??? ? ????. ?? ??? ??? ? ???? ?? ??, ??, ?? ??, ?? ?? ??? ? ?? ????? ? ??????.

?? ??? ? ???, ?? ?? ? ???? ??? ? ????.

?? ??? ?? ??

??

?? ? ?? ??

?? ??

?? ??

?? ??

???

?? ??

????? ?? ??? ?? ??? ?? ?????? ?? ?? ??? ?? ???? ??? ???????. ??? ??? ??? ?? ?? ???? ?? ?????. ???? ??? ?? ?? ? ???? ???? ?? ??? ???? ??? ??? ? ?? ??? ?????? ???. ?? 30 ? ?? ?? ???? WC ?? ???? ?? ?? ??? ????? ??? ?? ??? ?????.

??? ??

???

??? ????? ?? ???? ???? ??? ??????. WC Co ???? ????? ???????. CO? ??? WC? ??? ??? ? ?? ?? ?????. ?? ?? 13.2? ?? CO? ???? ??? ??? ?? ???? ? ????.

?? 13.3 ?? ? ?? ??? ???? WC Co ??? ?? ?? ?? ??? ?? : (a), (b) F8; (c), (d) M8; ? (E), (f) C8.

?? F8, M8 ? C8 ?? ? ?? ? ??? ?? ?? ?? ???? ??????. ?? ??? ???? ??? ?? ??? ?????. F8 ??? ??? ???? ??? ??? ????, M8 ? C8 ??? ??? ??? ?? ??? ??? ?? ??? ????. ?? ? ????, ?? ??? ??? ?? ??? ????, ?? ? ????? ??? ??? ?????. ??? ?? (HV)? 1500?? 2000 HV30?? ???? ?? ??? 7?? 15 MPa M1 / 2???.? ??? ??? ?? ??, ?? ?? ? ??? ??? ?????.

????? ????, ?? ??? ???? ??? ?? ????? ?????. CO? ?? ??? ???? ?? ??? ????? ??? ????? ????? (Jia et al., 2007). ??? ? ?? ??? ???? ?? ???? ??? ?? ???? ?? ???????.

??? ?? ?? ??? ????? ????? ??? ?? ??? ????? ????. ?? WC? ?? ??? ??? ????? ?????? ??????.

???-Ni

??? ????? ???? ?? ?? ? ????. ??? ?? ?? ??? ??? ????. ?? ???? ?? / ?? ??, ?? ?? ? ????? ????? ? ??? ? ????. WC Co ??? ?? ??? ???? ????. ??? WC?? ? ???? ??? WC ??? ???? ????? ?? ??? ?? ??? ?????.

???-Ag

Ag? ??? WC? ??? ?? ?? ??? ????. ??? ??? ?? ???, WC? ?? ??? ??? ????, ?? ??? ?? ? ?? ?? ?? (RC)? ?? ? ???. WC Ag ???? ???? Ag ??? ???? ?? ????, Ag ??? ???? ?? ??? ????? ?? ?? ? ?????. ?? WC? Ag? ??? ? ??? ?? ???. ??, ?? WC ??? ?? ??? ?? ?? ??????.

?? 13.4? ???? ?? ?? ? ?? ?? ?? ?? (RC)? ?????.

???? ??? RC? 10 ?? ????? ?? ??? ??? ???? ???,? ?? ? WC ?? ??? ???? 11e50. ?? ?? ??? ?? ??? 4 mm ? WC?? 50-55 wt% (?? ?? 60% ? 64.6%) ????, ?? ??? 4 mm ? WC?? 55-60 wt% (?? ?? 64.6% ? 69%) ????. 0.8 ? 1.5 mm. ???, ??? ??? ?? ??? ????, ??? Ag ????? ??? ?? ?????. ?? ??? ??, 1.5 ?? 4 mm WC ?? ??? ?? ?? ??? ??????, ?? ?? ?? ?? ?? ????.

???

RE? ?? ??? ??? ??? ??? ? ?? ??? ????? WC Co?? ??? ??? ?? ?? ??? ????? ???? ??? ???? ????.

?? 13.4 ??? 11?? 50 ??? WC ??? ?? ??? ?? ??? Ag ?? ? WC ?? ????? ?? ?? ?? ??? ?? co ?? Ni??. WC coere (20% RE ??)? ?? ?? ??? ???, WC coere? CO? ???? HCP ??? ?? ???? ??? ??? ????? ??? ??????. ????? ?? WC Ni?? re? ???? ??? ??? ????. WC Co? ?? ??? 2 ?? ????? ??? ??? ????? ?? ??? ???? ? ?????. WC ? Re ???? ?? ??? ? ? ????? ? ??? ??? ?? ? ? 2400kg / mm ~ 2 ??? HV? ??????? (WC-Co? ?? 1700kg / mm ~ 2 ??).

??? ?? ?

??? -FeAl

?? ?? ? ?? ??? ????? ?? ? ???? ???? ??? ?????. ? ???? ??? ??? ? ??? ? ???, ?? ??, ?? ??, ??? ????, ?? ??? ? ??? ???? ???. ????? ?????? WC? ?????. WC FeAl ? WC Co? ?? ? ?? ??? ????? ?????. WC Co ??? ?? ? ????? ?? WC Co ??? ??? ????? ?????. ??? ??? ? ? ??? ???? WC Co? ?? ? ? ??? ??? ? ????. ?? ? ?? ? / ?? ?? ???? ?? ? WC FeAl ?? ??? ?? ?? ?? ??? ?? 13.5? ?? ????. ?? 13.5? 3 ?? ??? ?? ?????. ?? 13.5?? ?? ?? ??? ?? ??? ?? WC ??? ?? ??? ?????. ? ? ?? ??? ??? ?? ?? ?? WC ??? ???? FeAl ??? ?? ?? ????. ??? ??? ??? ?, ?? ??? ?? ? / ?? ?? ??? ???? ????. DR ?? (?? ????? ???? ?? ? ???)? ??? ??? ?? ? ??? ?? ??? ????.

?? 13.5 ??? ?? ???? ?? ? WC-FeAl ?? ??? ?? ?? ??.

??? ????

???-MgO

WC-mgo ?? ??? WC ????? MgO ??? ??? ?? ?? ???? ???, ?? ??? ?? ??? ??? ??? ??? ??? ??? ?????. ??? ??? ??????,? ??? ??, ?? ??? ?? ?? ? ??? ????. ?? ? ??? ??? VC, Cr3C2 ? ?? ?? ?? ???? ???? ?? ???? ?? ??? ?? ??? ??? ??? ??? ??? ?? ? ? ????.

WC-Al2O3

Al2O3? ???, ??? ??? ???? ??? WC ? ???? ???? ? ??? ???????.

?? ?? ? ?? ??? wc-40vol% Al2O3 ???? ?? ?? ? ??? ??? ??? ??? ???. ?? ?? ? ?? ??? ???? ??, ?? ?? ? ?? ??? ????. ???, ?? ? ?? ??? ?? ?? ??? ?? ?????. ?? ??? ?? ??? ?? ??? ? ?? ??? ??? ????. wc-40vol% Al 2O 3 ????? ?? ?? ????? 2 ? ? ?? ?? ?????. ?? ??? ??? HV? ? 20e25gpa?? ?? ??? 5e6mpa.m1 / 2???.

?? 13.6? ???? ??? ?? ??, ?? ?? ? ?? ?? ??? ?? ??? ?????. ? ???? ? ?? ??? ???? ?? ??????? (Mao et al., 2015). ?? WC? ??? ?? ?? ?? ??? ?? ????. Al2O3? ??? ?? ??? ?? ????, ??? ????? ??? ??? WC? ???? ???, wc-al2o3 ???? ??? ????. ?? 13.6? ?? ??? ??? ??? ???? ???? ??? ?? ??? ?? ?? ? ??? ????? ?? ?????. 

??? ???

??? cBN

CBN? ??, ? ??? ? ??? ?? ??? ???? ??? WC Co? CBN? ???? ????, ?? ? ??? ??? ??? ???? ? ????. CBN? WC ????? ???? ?? ???? ?????. ??, ?? ?? ?? CBN ??? ??? ?? ? ?? ?? ??? ?? ???. CBN ?? ???? 2 ?? ?? ???? CBN?? hBN??? ?? ? B? N ??? ?? ?? ????, CBN? ????? ?? ??? ????.

??? ?????

WC ?????? ?? ??, ?? ?? ?? ? ?? ??? ?????. ? ??? ?????? ???? ??? ?? ?? ?? ???? ????? ??? ? ????. ? ??? ??? ??????? ? ?? ??? ??, ??? ??? ?? ??? ?? ? ? ????.

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introductionSteel is quenched by heating the steel to a temperature above the critical temperature Ac3 (hypo-eutectoid steel) or Ac1 (hypereutectoid steel), holding it for a period of time so as to be austenitized in whole or in part, and then cooled at a temperature greater than the critical cooling rate Rapid cooling to below the Ms (or Ms near the isothermal) martensitic (or bainite) heat treatment process. The solution treatment of materials such as aluminum alloys, copper alloys, titanium alloys, toughened glass, etc., or heat treatment processes with rapid cooling is also commonly referred to as quenching. Quenching is a common heat treatment process, mainly used to increase the hardness of the material. Usually from the quenching medium, can be divided into water quenching, oil quenching, organic quenching. With the development of science and technology, some new quenching processes have emerged.1 high-pressure air-cooled quenching methodWorkpieces in the strong inert gas flow quickly and evenly cooling, to prevent surface oxidation, to avoid cracking, reduce distortion, to ensure that the required hardness, mainly for tool steel quenching. This technology has recently progressed rapidly and the range of applications has also expanded considerably. At present, the vacuum gas quenching technology developed rapidly, and the negative pressure (<1 × 105 Pa) high flow rate gas cooling followed by gas cooling and high pressure (1 × 105 ~ 4 × 105 Pa) 10 × 105 Pa) air-cooled, ultra-high pressure (10 × 105 ~ 20 × 105 Pa) air-cooled and other new technologies not only greatly enhance the vacuum quenching ability of air-cooled, and quenched the workpiece surface brightness is good, small deformation, but also A high efficiency, energy saving, pollution-free and so on. The use of vacuum high-pressure gas-cooled quenching is the quenching and tempering of materials, the solution, aging, ion carburizing and carbonitriding of stainless steel and special alloys, as well as vacuum sintering, cooling and quenching after brazing. With 6 × 105 Pa high pressure nitrogen cooling quenching, the load can only be cooled loose, high-speed steel (W6Mo5Cr4V2) can be hardened to 70 ~ 100 mm, high alloy hot work die steel up to 25 ~ 100 mm, gold Cold work die steel (such as Cr12) up to 80 ~ 100 mm. When quenched with 10 × 10 5 Pa of high pressure nitrogen, the cooled load can be intensive, increasing the load density by about 30% to 40% over cooling of 6 × 10 5 Pa. When quenched with 20 × 10 5 Pa of ultra-high pressure nitrogen or a mixture of helium and nitrogen, the cooled loads are dense and can be bundled together. The density of 6 × 105 Pa nitrogen cooling 80% to 150%, can be cooled all high-speed steel, high alloy steel, hot work tool steel and Cr13% chromium steel and more alloy oil quenched steel, such as more Large-size 9Mn2V steel. Dual-chamber air-cooled quench furnaces with separate cooling chambers have better cooling capacity than the same type of single chamber furnaces. The 2 × 105 Pa nitrogen cooled double chamber furnace has the same cooling effect as the 4 × 105 Pa single chamber furnace. However, operating costs, low maintenance costs. As China’s basic materials industry (graphite, molybdenum, etc.) and ancillary components (motor) and other levels to be improved. Therefore, to improve the 6 × 105 Pa single-chamber high-pressure vacuum care while maintaining the development of dual-chamber pressure and high-pressure air-cooled quenching furnace more in line with China’s national conditions.Figure 1 high-pressure air-cooled vacuum furnace2 strong quenching methodConventional quenching is usually with oil, water or polymer solution cooling, and strong quenching rule with water or low concentrations of salt water. Strong quenching is characterized by extremely fast cooling, without having to worry about excessive distortion of steel and cracking. Conventional quench cooling to the quenching temperature, the steel surface tension or low stress state, and strong quenching in the middle of cooling, the workpiece heart is still in the hot state to stop cooling, so that the formation of surface compressive stress. Under the severe quenching condition, the supercooled austenite on the surface of the steel is subjected to compressive stress of 1200 MPa when the cooling rate of the martensitic transformation zone is higher than 30 ℃ / s, so that the yield strength of the steel after quenching is increased by at least 25%.Principle: Steel from austenitizing temperature quenching, the temperature difference between the surface and the heart will lead to internal stress. Phase change of the specific volume of phase change and phase change plastic will also cause additional phase transformation stress. If the thermal stress and phase transition stress superposition, that is, the overall stress exceeds the yield strength of the material will be plastic deformation occurs; if the stress exceeds the tensile strength of hot steel will form a quenching crack. During intensive quenching, the residual stress caused by the phase change plasticity and the residual stress increase due to the specific volume change of austenite-martensite transformation. In the intense cooling, the workpiece surface immediately cooled to the bath temperature, the heart temperature almost unchanged. Rapid cooling causes a high tensile stress that shrinks the surface layer and is balanced by the heart stress. The increase of temperature gradient increases the tensile stress caused by the initial martensitic transformation, while the increase of the martensite transformation start temperature Ms will cause the surface layer to expand due to the phase transition plasticity, the surface tensile stress will be significantly reduced and transformed into compressive stress, Surface compressive stress is proportional to the amount of surface martensite produced. This surface compressive stress determines whether the heart undergoes martensitic transformation under compressive conditions or, on further cooling, reverses the surface tensile stress. If the martensitic transformation of the heart volume expansion is large enough, and the surface martensite is very hard and brittle, it will make the surface layer due to stress reversal rupture. To this end, the steel surface should appear compressive stress and heart martensitic transformation should occur as late as possible.Strong quenching test and steel quenching performance: The strong quenching method has the advantage of forming compressive stress in the surface, reducing the risk of cracking and improve the hardness and strength. Surface formation of 100% martensite, the steel will be given the largest hardened layer, it can replace the more expensive steel carbon steel, a strong quenching can also promote uniform mechanical properties of steel and produce the smallest distortion of the workpiece . Parts after quenching, the service life under alternating load can be increased by an order of magnitude. [1]Figure 2 strong quenching crack formation probability and cooling rate relationship3 water-air mixture cooling methodBy adjusting the pressure of water and air and the distance between the atomizing nozzle and the surface of the workpiece, the cooling capacity of the water-air mixture can be varied and the cooling can be uniform. Production practice shows that the use of the law on the shape of complex carbon steel or alloy steel parts induction hardening surface hardening, which can effectively prevent the generation of quenching cracks.Figure 3 water-air mixture4 boiling water quenching methodUsing 100 ℃ boiling water cooling, can get a better hardening effect, for quenching or normalizing steel. At present, this technology has been successfully applied to the ductile iron quenching. Taking aluminum alloy as an example: According to the current heat treatment specifications for aluminum alloy forgings and forgings, the quenching water temperature is generally controlled below 60 ° C, the quenching water temperature is low, the cooling speed is high, and a large residual stress after quenching occurs. In the final machining, the internal stress is out of balance due to the inconsistency of the surface shape and size, resulting in the release of residual stress, resulting in deformed, bent, oval and other deformed parts of the machined part becoming irreversible final wastes with serious loss . For example: propeller, compressor blades and other aluminum alloy forging deformation after machining obvious, resulting in parts size tolerance. Quenching water temperature increased from room temperature (30-40 ℃) to boiling water (90-100 ℃) temperature, the average forging residual stress decreased by about 50%. [2]Figure 4 boiling water quenching diagram5 hot oil quenching methodThe use of hot quenching oil, so that the workpiece before further cooling at a temperature equal to or near the temperature of Ms point in order to minimize the temperature difference, can effectively prevent quenching the workpiece distortion and cracking. The small size of the alloy tool steel die cold 160 ~ 200 ℃ in hot oil quenching, can effectively reduce distortion and avoid cracking.Figure 5 hot oil quenching diagram6 Cryogenic treatment methodThe quenched workpiece is continuously cooled from room temperature to a lower temperature so that the retained austenite continues to be transformed into martensite, the purpose of which is to improve the hardness and abrasion resistance of the steel, improve the structural stability and the dimensional stability of the workpiece, and effectively Improve tool life.Cryogenic treatment is liquid nitrogen as a cooling medium for material processing methods. Cryogenic treatment technology was first applied to the wear tools, mold tool materials, and later extended to alloy steel, carbide, etc., using this method can change the internal structure of metal materials, thereby improving the mechanical properties and processing properties, which is currently One of the latest toughening processes. Cryogenic treatment (Cryogenictreatment), also known as ultra-low temperature treatment, generally refers to the material below -130 ℃ for processing to improve the overall performance of the material. As early as 100 years ago, people began to cold treatment applied to watch parts, found to improve the strength, wear resistance, dimensional stability and service life. Cryogenic treatment is a new technology developed on the basis of ordinary cold treatment in the 1960s. Compared with the conventional cold treatment, cryogenic treatment can further improve the mechanical properties and stability of the material, and has a broader application prospect.Cryogenic treatment mechanism: After cryogenic treatment, the residual austenite in the internal structure of the metal material (mainly mold material) is transformed to martensite, and the precipitated carbide is also precipitated in the martensite, so that the martensite can be eliminated In the residual stress, but also enhance the martensite matrix, so its hardness and wear resistance also will increase. The reason for the increase in hardness is due to the transformation of part of the retained austenite into martensite. The increase in toughness is due to the dispersion and small η-Fe3C precipitation. At the same time, the carbon content of the martensite decreases and the lattice distortion decreases, Plasticity improvement.Cryogenic treatment equipment mainly consists of liquid nitrogen tank, liquid nitrogen transmission system, deep cold box and control system. In the application, cryogenic treatment is repeated several times. Typical processes such as: 1120 ℃ oil quenching + -196 ℃ × 1h (2-4) deep cryogenic treatment +200 ℃ × 2h tempering. After the treatment of the organization there has been the transformation of austenite, but also precipitated from the quenched martensite dispersion of highly coherent relationship with the matrix of ultrafine carbides, after subsequent low temperature tempering at 200 ℃, the growth of ultrafine carbides Dispersed ε carbides, the number and dispersion significantly increased. The cryogenic treatment is repeated a number of times. On the one hand, the superfine carbides are precipitated from the martensite transformed from the retained austenite at the time of the previous cryogenic cooling. On the other hand, fine carbides continue to be precipitated in the quenched martensite. Repeated process can make the matrix compressive strength, yield strength and impact toughness increased, improve the toughness of steel, while making the impact wear resistance was significantly improved.Figure 6 cryogenic treatment device schematicSome of the workpiece on the strict size requirements, does not allow processing due to thermal stress caused by excessive deformation, cryogenic treatment should be controlled cooling rate. In addition, in order to ensure the uniformity of the temperature field inside the equipment and reduce the temperature fluctuation, the design of the cryogenic treatment system should take into account the system temperature control accuracy and the rationality of the flow field arrangement. In the system design should also pay attention to meet the less energy consumption, high efficiency, easy operation and other requirements. These are the current development trend of cryogenic treatment system. In addition, some developing refrigeration systems whose refrigeration temperature extends from room temperature to low temperature are also expected to develop into liquid-free cryogenic treatment systems with the decrease of their minimum temperature and the improvement of refrigeration efficiency. [3]References:[1]樊東黎. 強(qiáng)烈淬火——一種新的強(qiáng)化鋼的熱處理方法[J]. 熱處理, 2005, 20(4): 1-3[2]宋微, 郝冬梅, 王成江. 沸水淬火對(duì)鋁合金鍛件組織與機(jī)械性能的影響[J]. 鋁加工, 2002, 25(2): 1-3[3]夏雨亮, 金滔, 湯珂. 深冷處理工藝及設(shè)備的發(fā)展現(xiàn)狀和展望[J]. 低溫與特氣, 2007, 25(1): 1-3
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First, the molecular beam epitaxial profileIn the ultra-high vacuum environment, with a certain thermal energy of one or more molecules (atoms) beam jet to the crystal substrate, the substrate surface reaction processMolecules in the “flight” process almost no collision with the ambient gas, in the form of molecular beam to the substrate, the epitaxial growth, hence the name.Properties: A vacuum deposition methodOrigin: 20th century, the early 70s, the United States Bell laboratoryApplications: epitaxial growth atomic level precise control of ultra-thin multi-layer two-dimensional structure materials and devices (super-character, quantum wells, modulation doping heterojunction, quantum yin: lasers, high electron mobility transistors, etc.); combined with other processes, But also the preparation of one-dimensional and zero-dimensional nano-materials (quantum lines, quantum dots, etc.).Typical features of MBE:(1) The molecules (atoms) emitted from the source furnace reach the substrate surface in the form of a “molecular beam” stream. Through the quartz crystal film thickness monitoring, can strictly control the growth rate.(2) molecular beam epitaxy growth rate is slow, about 0.01-1nm / s. Can achieve single atomic (molecular) layer epitaxy, with excellent film thickness controllability.(3) By adjusting the opening and closing of the baffle between the source and the substrate, the composition and the impurity concentration of the film can be strictly controlled, and selective epitaxial growth can be achieved.(4) non-thermal equilibrium growth, the substrate temperature can be lower than the equilibrium temperature, to achieve low temperature growth, can effectively reduce the interdiffusion and self-doping.(5) with reflective high-energy electron diffraction (RHEED) and other devices, can achieve the original price observation, real-time monitoring.Growth rate is relatively slow, both MBE is an advantage, but also its lack, not suitable for thick film growth and mass production.Second, silicon molecular beam epitaxy1 basic profileSilicon molecular beam epitaxy includes homogeneous epitaxy, heteroepitaxy.The silicon molecular beam epitaxy is the epitaxial growth of silicon (or silicon-related materials) on a suitably heated silicon substrate by physical deposition of atoms, molecules or ions.(1) during the epitaxial period, the substrate is at a lower temperature.(2) Simultaneous doping.(3) the system to maintain high vacuum.(4) pay special attention to the atomic clean surface.Figure 1 Schematic diagram of the working principle of silicon MBE2 Development history of silicon molecular beam epitaxyDeveloped relative to CVD defects.CVD defects: substrate high temperature, 1050oC, to the doping serious (with high temperature). The original molecular beam epitaxy: the silicon substrate heated to the appropriate temperature, vacuum evaporation of silicon to the silicon substrate, the epitaxial growth.Growth Criteria: The incident molecules move sufficiently to the hot surface of the substrate and are arranged in the form of a single crystal.3 The importance of silicon molecular beam epitaxyThe silicon MBE is carried out in a strictly controlled cryogenic system.(1) can well control the impurity concentration to reach the atomic level. The undoped concentration is controlled at <3 × 1013 / cm3.(2) The epitaxy can be carried out under the best conditions without defects.(3) The thickness of the epitaxial layer can be controlled within the thickness of the single atomic layer, superlattice epitaxy, several nm ~ several tens of nm, which can be designed manually, and the preparation of excellent performance of the new functional materials.(4) Homogeneous epitaxy of silicon, heteroepitaxy of silicon.4 epitaxial growth equipmentDevelopment direction: reliability, high performance and versatilityDisadvantages: high prices, complex, high operating costs.Scope: can be used for silicon MBE, compound MBE, III-V MBE, metal semiconductor MBE is developing.Basic common features:(1) basic ultra-high vacuum system, epitaxial chamber, Nuosen heating room;(2) analysis means, LEED, SIMS, Yang EED, etc .;(3) injection chamber.Figure 2 Schematic diagram of silicon molecular beam epitaxial system(1) electron beam bombardment of the surface of the silicon target, making it easy to produce silicon molecular beam. In order to avoid the radiation of the silicon molecular beam to the side to cause adverse effects, large area screen shielding and collimation is necessary.(2) resistance to heating the silicon cathode can not produce strong molecular beam, the other graphite citrus pots have Si-C stained, the best way is to electron beam evaporation to produce silicon source. Because, some parts of the silicon MBE temperature is higher, easy to evaporate, silicon low evaporation pressure requirements of the evaporation source has a higher temperature. At the same time, the beam density and scanning parameters to control. Making the silicon melting pit just in the silicon rod, silicon rods become high-purity citrus.There are several kinds of monitoring molecular beam:(1) Quartz crystal is often used to monitor beam current, beam shielding and cooling appropriate, can be satisfied with the results, but the noise affects the stability. After several μm, the quartz crystal loses its linearity. Frequent exchange, the main system is often inflated, which is not conducive to work.(2) small ion table, measured molecular beam pressure, rather than measuring the molecular beam flux. Due to the deposition on the system components leaving the standard.(3) low-energy electron beam, through the molecular beam, the use of electrons detected by the excitation fluorescence. The atoms are excited and quickly degrade to the ground state to produce uv fluorescence, and the optical density is proportional to the beam density after optical focusing. Do the feedback control of the silicon source. Inadequate: cut off the electron beam, most of the infrared fluorescence and background radiation will make the signal to noise ratio deteriorated to the extent of instability. It only measured atomic class, can not measure molecular substances.(4) Atomic absorption spectra, monitoring the beam density of doped atoms.With the intermittent beam current, Si and Ga were detected by 251.6nm and 294.4nm optical radiation respectively. The absorption intensity of the beam through the atomic beam was converted into atomic beam density and the corresponding ratio was obtained.Molecular beam epitaxy (MBE) substrate base is a difficult point.MBE is a cold wall process, that is, silicon substrate heating up to 1200 ℃, the environment to room temperature. In addition, the silicon wafer to ensure uniform temperature. Hill resistance refractory metal and graphite cathode, the back of the radiation heating, and the entire heating parts are installed in liquid nitrogen cooled containers, in order to reduce the thermal radiation of the vacuum components. The substrate is rotated to ensure uniform heating. Free deflection, can enhance the secondary implantation doping effect.
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1, Review of Organic Halide Perovskite – related Photoelectric PropertiesFigure 1 Spectral position and PL peakOrganic halide perovskites are widely used in optoelectronics research. Methyl ammonium and formamidine lead iodide as photovoltaics show excellent photoelectric properties and stimulate researchers’ enthusiasm for light-emitting devices and photodetectors. Recently, the University of Toronto Edward H. Sargent (Correspondent) team of organic metal halide perovskite optical and electrical properties of the material were studied. Outlines how material composition and form are associated with these attributes, and how these properties ultimately affect device performance. In addition, the team also analyzed different material properties of the perovskite materials, in particular the bandgap, mobility, diffusion length, carrier lifetime and trap density.The Electrical and Optical Properties of Organometal Halide Perovskites Relevant to Optoelectronic Performance（Adv.Mater.,2017,DOI: 10.1002/adma.201700764）2, Advanced Materials Overview: 2D optoelectronic applications of organic materials Figure 2 Several key steps in the application of two-dimensional organic materialsThe 2D material with atomic thin structure and photoelectron properties has attracted the interest of researchers in applying 2D materials to electronics and optoelectronics. In addition, as a two-dimensional material series of emerging areas, the organic nanostructure assembled into 2D form provides molecular diversity, flexibility, ease of processing, light weight, etc., for optoelectronic applications provides an exciting prospect. Recently, Tianjin University, Professor Hu Wenping, Ren Xiaochen assistant researcher (common newsletter) and others reviewed the application of organic two-dimensional materials in optoelectronic devices. Examples of materials include 2D, organic, crystalline, small molecules, polymers, self- Covalent organic skeleton. The application of 2D organic crystal fabrication and patterning technology is also discussed. Then the application of optoelectronic devices is introduced in detail, and the prospect of 2D material is briefly discussed.2D Organic Materials for Optoelectronic Applications（Adv.Mater.,2017,DOI: 10.1002/adma.201702415）3, Advanced Materials Review: 2D Ruddlesden-Popper Perovskite PhotonicsFigure 3 Schematic diagram of 3D and 2D perovskite structuresThe traditional 3D organic-inorganic halide perovskite has recently undergone unprecedented rapid development. However, their inherent instabilities in moisture, light and calories remain a key challenge before commercialization. In contrast, the emerging two-dimensional Ruddlesden-Popper perovskite has received increasing attention due to its environmental stability. However, 2D perovskite research has just started. Recently, the University of Fudan University, Liang Ziqi (Corresponding author) team published a review first introduced 2D perovskite and 3D control of a detailed comparison. And then discussed the two-dimensional perovskite organic interval cationic engineering. Next, quasi-two-dimensional perovskites between 3D and 2D perovskites were studied and compared. In addition, 2D perovskite unique exciton properties, electron-phonon coupling and polaron are also shown. Finally, a reasonable summary of the structure design, growth control and photophysics research of 2D perovskite in high performance electronic devices is presented.2D Ruddlesden–Popper Perovskites for Optoelectronics（Adv.Mater.,2017,DOI: 10.1002/adma.201703487）4, Science Advances Summary: Lead Halide Perovskite: Crystal-Liquid Binary, Phonon Glass Electronic Crystals and Great Polaron FormationFigure 4 CH3NH3PbX3 perovskite structureLead anodized perovskite has proven to be a high performance material in solar cells and light emitting devices. These materials are characterized by the expected coherent band transport of crystalline semiconductors, as well as the dielectric response and phonon dynamics of the liquid. This “crystal-liquid” duality means that lead halide perovskites belong to phonon glass electron crystals – a class of thermoelectric materials that are considered to be the most efficient. Recently, the University of Columbia Zhu Xiaoyang (communication author) team reviewed the crystal-liquid duality, the resulting dielectric response responsible for the formation and selection of carrier polaron, which causes perovskite with defect tolerance, moderate Of the carrier mobility and the combined performance of the radiation. Large polaron formation and phonon glass characteristics can also explain the significant reduction in carrier cooling rates in these materials.Lead halide perovskites: Crystal-liquid duality, phonon glass electron crystals, and large polaron formation（Sci. Adv.,2017,DOI:10.1126/sciadv.1701469）5, Progress in Polymer Science Review: Lithography of silicon-containing block copolymersFig.5 Melt phase diagram of diblock copolymerRecently, the National Tsinghua University Rong-Ming Ho (Correspondent) and others published a summary of the different methods through the preparation of ordered block copolymer (BCP) film the latest progress, focusing on the use of silicon-containing BCP as lithography applications. With the advantages of Si-containing blocks, these BCPs have smaller feature sizes due to their high resolution, large segregation intensity and high etch contrast. Considering that poly (dimethylsiloxane) (PDMS) has been extensively studied in Si-containing BCPs, the possibility of photolithography using PDCP-containing BCP has been demonstrated through previous and ongoing studies. Subsequent sections detail the main results of the DSA approach. The new trend of lithographic printing application and the application of photolithography nano – pattern using silicon – containing BCPs are also discussed. Finally, the conclusion and prospect of BCP lithography are introduced.Silicon-Containing Block Copolymers for Lithographic Applications（Prog. Polym. Sci.,2017,DOI:10.1016/j.progpolymsci.2017.10.002）6, Angewandte Chemie International Edition Overview: CH3NH3PbI3 perovskite solar cell theoretical studyFigure 6 Electronic density patternPower conversion efficiency (PCEs) of more than 22% of the hybridized perovskite perovskite solar cells (PSCs) has attracted considerable attention. Although perovskite plays an important role in the operation of PSCs, the basic theory associated with perovskite remains unresolved. Recently, Professor Xun Nining (Communication Author) of Xi’an University of Architecture and Technology, according to the first principle, evaluated the existing theory of structure and electronic properties, defects, ion diffusion and transfer current of CH3NH3PbI3 perovskite, and ion transport Influence on PSC Current – Voltage Curve Hysteresis. The moving current associated with the possible ferroelectricity is also discussed. And emphasizes the benefits, challenges and potential of perovskite for PSCs.Theoretical Treatment of CH3NH3PbI3 Perovskite Solar Cells（Angew. Chem. Int. Ed.,2017,DOI: 10.1002/anie.201702660）7, Chemical Society Reviews Overview: Reductive Batteries for Electromechanical Active Materials for Molecular EngineeringFigure 7 Molecular engineering for redox substances for sustainable RFBAs an important large energy storage system, redox batteries (RFBs) have high scalability and independent energy and power control capabilities. However, conventional RFB applications are subject to performance and limitations on high cost and environmental issues associated with the use of metal-based redox substances. Recently, the University of Texas at Austin Guihua Yu (communication author) team proposed the design of these new redox substances system molecular engineering program. The article provides a detailed synthesis strategy for modifying organometallic and organometallic redox substances in terms of solubility, oxidation-reduction potential and molecular size. And then introduced recent advances covering the reaction mechanism of the redox species classified by its molecular structure, the specific functionalization methods and electrochemical properties. Finally, the author analyzes the future development direction and challenge of this emerging research field.Molecular engineering of organic electroactive materials for redox flow batteries （Chem.Soc.Rev.,2017,DOI: 10.1039/C7CS00569E）8, Chemical Society Reviews Overview: Atomic level for energy storage and conversion Non-layered nanomaterialsFigure 8 Atomic-grade layered and non-layered nanomaterialsSince the discovery of graphene, the two-dimensional nanomaterials with large atomic thickness and large lateral dimension are highly studied because of their high specific surface area, heterogeneous electronic structure and attractive physical and chemical properties. Recently, Wulonggong University Dushi University academician (communication author) team comprehensively summed up the atomic thickness of non-layered nano-materials preparation method, studied its heterogeneous electronic structure, the introduction of electronic structure operation strategy, and outlined its energy storage and conversion Applications, with particular emphasis on lithium-ion batteries, sodium ion batteries, oxygen, CO2 reduction, CO oxidation reaction. Finally, based on the current research progress, put forward the future direction – in practical application to enhance the performance and new features to explore.Atomically thin non-layered nanomaterials for energy storage and conversion （Chem.Soc.Rev.,2017,DOI:10.1039/C7CS00418D）9, Chemical Reviews Overview: Electrochemical Applications in the Synthesis of Heterocyclic StructuresFigure 9 Mechanism of electro-induced cationic chain reactionThe heterocycle is one of the largest organic compounds to date, and the preparation and transformation of heterocyclic structures have been of great interest to organic chemistry researchers. Various heterocyclic structures are widely found in biologically active natural products, organic materials, agrochemicals and drugs. When people notice that about 70% of all drugs and agrochemicals have at least one heterocycle, people can not ignore them importance. Recently, Professor Zeng Chengchao of Beijing University of Technology (Correspondent Author) team reviewed the progress of electrochemical construction of heterocyclic compounds published by intramolecular and intermolecular cyclization since 2000.Use of Electrochemistry in the Synthesis of Heterocyclic Structures（Chem. Rev.,2017,DOI:10.1021/acs.chemrev.7b00271）
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First, the development of a brief historyThe first stage: 1945 to 1951, the invention of nuclear magnetic resonance and lay the theoretical and experimental basis of the period: Bloch (Stanford University, observed in the water proton signal) and Purcell (Harvard University, observed in the paraffin proton signal) obtained Nobel bonus.The second stage: 1951 to 1960 for the development period, its role by chemists and biologists recognized, to solve many important problems. 1953 appeared in the first 30MHz nuclear magnetic resonance spectrometer; 1958 and early in the emergence of 60MHz, 100MHz instrument. In the mid-1950s, 1H-NMR, 19F-NMR and 31P-NMR were developed.The third stage: 60 to 70 years, NMR technology leap period. Pulse Fourier transform technology to improve the sensitivity and resolution, can be routinely measured 13C nuclear; dual frequency and multi frequency resonance technology;The fourth stage: the late 1970s theory and technology development mature.1,200, 300, 500 MHz and 600 MHz superconducting NMR spectrometers;2, the application of a variety of pulse series, in the application made important development;3, 2D-NMR appeared;4, multi-core research, can be applied to all magnetic cores;5, there have been “nuclear magnetic resonance imaging technology” and other new branch disciplines.Second, the main purpose:1. Determination and confirmation of the structure, and sometimes can determine the configuration, conformation2. Compound purity inspection, the sensitivity of thinner, paper chromatography high3. Mixture analysis, such as the main signal does not overlap, without separation can determine the proportion of the mixture.4. Proton exchange, the rotation of a single bond, the transformation of the ring and other chemical changes in the speed of the presumption1. the spin of the nucleusOf the isotopes of all elements, about half of the nuclei have spin motion. These spin nuclei are the object of nuclear magnetic resonance. Spin Quantum: The number of quantum numbers describing the spin motion of the nucleus, which can be an integer, a half integer, or a zero.In the organic compound composition elements, C, H, O, N is the most important element. In its isotopes, 12C, 16O are non-magnetic and therefore do not undergo nuclear magnetic resonance. 1H natural abundance of large, strong magnetic, easy to determine, so the NMR study was mainly for the proton. 13C abundance is small, only 12C 1.1%, and the signal sensitivity is only a proton to get 1/64. So the total sensitivity of only 1/6000 of 1H, more difficult to determine. But in the past 30 years, nuclear magnetic resonance instrument is greatly improved, can be measured in a short time 13C spectrum, and give more information, has become the main means of NMR. 1H, 19F, 31P natural abundance of large, strong magnetic, and nuclear charge distribution of spherical, the most easy to determine.2. Nuclear magnetic resonance phenomena① Precession: Spin with a certain magnetic moment Under the action of external magnetic field H0, this core will form angle for the kinematic motion: is the precession kinematic velocity, which is proportional to H0 (external magnetic field strength).② spin nuclear in the external magnetic field orientation: no external magnetic field, the spin magnetic orientation is chaotic. The magnetic core is in the external magnetic field H0, with (2I + 1) orientation. The spin of the magnetic core in the external magnetic field can be analogous to the precession (pronation, swing) of the gyroscope in the gravitational field.③ conditions of nuclear magnetic resonanceThe magnetic resonance magnetic field must have the magnetic nuclei, the external magnetic field and the RF magnetic field. The frequency of the RF magnetic field is equal to the precession frequency of the spin nucleus, and the resonance occurs from the low energy state to the high energy state.④ nuclear magnetic resonance phenomenon:In the vertical direction of the external magnetic field H0, a rotating magnetic field H1 is applied to the precession nucleus. If the rotational frequency of H1 is equal to the rotational precession frequency of the nucleus, the precession nucleus can absorb energy from H1 and transition from low energy state to high energy state Nuclear magnetic resonance.3. Saturation and relaxationLow energy nuclear is only 0.001% higher than high energy nuclear. Therefore, the low energy state core is always more than the high energy nuclear, because such a little surplus, so can observe the absorption of electromagnetic waves. If the nuclear continuous absorption of electromagnetic waves, the original low energy state is gradually reduced, the intensity of the absorption signal will be weakened, and ultimately completely disappeared, this phenomenon is called saturation. When saturation occurs, the number of cores in the two spin states is exactly the same. In the external magnetic field, the low-energy nuclei are generally more nuclear than the high-energy state, absorb the electromagnetic wave energy and migrate to the high-energy state of the core will be released by a variety of mechanisms of energy, and return to the original low energy state, this process called relaxation.4. Shield effect – chemical shift① ideal state of resonanceFor isolated, bare nuclei, ΔE = (h / 2π) γ · H;Under certain H0, a nucleus has only one ΔEΔE = E outside = hνOnly the only frequency ν of absorptionSuch as H0 = 2.3500T, 1H absorption frequency of 100 MHz, 13C absorption frequency of 25.2 MHz② real core: shielding phenomenonNuclear outside the electron (not isolated, not exposed)In the compounds: the interatomic binding (role) is different, such as chemical bonds, hydrogen bonds, electrostatic interactions, intermolecular forcesImagine: In H0 = 2.3500 T, due to the outer electrons of the shield, in the nuclear position, the real magnetic field is slightly smaller than 2.3500 TResonance frequency slightly higher than 100 MHzHow much is it? 1H is 0 to 10, and 13C is 0 to 250The hydrogen nuclei have electrons outside, and they repel the magnetic field lines of the magnetic field. For the nucleus, the surrounding electrons are shielded (Shielding) effect. The greater the density of the electron cloud around the core, the greater the shielding effect, the corresponding increase in magnetic field strength to make it resonant. The electron cloud density around the nucleus is affected by the connected groups, so the nuclei of different chemical environments, they suffer from different shielding effects, their nuclear magnetic resonance signals also appear in different places.③ If the instrument is measured with a 60MHz or 100MHz instrument, the electromagnetic wave frequency of the organic compound proton is about 1000Hz or 1700Hz. In determining the structure, the need to determine the correct resonant frequency, often requires several Hz accuracy, generally with the appropriate compound as the standard to determine the relative frequency. The difference between the resonant frequency of the standard compound and the resonant frequency of a proton is called the chemical shift.5. H NMR spectroscopy informationThe number of signals: how many different types of protons are present in the moleculeThe position of the signal: the electronic environment of each proton, the chemical shiftThe intensity of the signal: the number or number of each protonSplit situation: how many different protons are presentThe chemical shift of common types of organic compounds① induced effect② conjugate effectThe conjugation effect is weak or enhanced by proton shielding due to the displacement of the π electrons③ anisotropic effectIt is difficult to explain the chemical shift of H with respect to pi-electrons, and it is difficult to explain the electronegativity④ H key effectROH, RNH2 in 0.5-5, ArOH in 4-7, the range of change, the impact of many factors; hydrogen bonding with temperature, solvent, concentration changes significantly, you can understand the structure and changes related to hydrogen bonds.⑤ solvent effectBenzene forms a complex with DMF. The electron cloud of the benzene ring attracts the positive side of the DMF, rejecting the negative side. α methyl is in the shielding region, the resonance moves to the high field; and β methyl is in the masking region, the resonance absorption moves to the low field, and the result is that the two absorption peak positions are interchanged.
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First, the basic concept of particle size analysis(1) particles: with a certain size and shape of small objects, is the basic unit of the composition of the powder. It is very small, but microscopic but contains a lot of molecules and atoms;(2) particle size: the size of particles;(3) particle size distribution: a certain way to reflect a series of different particle size particles, respectively, the percentage of the total powder;(4) the representation of the particle size distribution: table method (interval distribution and cumulative distribution), graphical method, function method, common R-R distribution, normal distribution;(5) particle size: the diameter of particles, usually in microns as a unit;(6) Equivalent particle size: When a particle of a physical properties and homogeneous spherical particles the same or similar, we use the spherical particles straightDiameter to represent the diameter of the actual particles;(7) D10, the cumulative distribution of 10% of the corresponding particle size; D50, the cumulative distribution of the percentage reached 50% of the corresponding particle size; also known as the median or median particle size; D90, the cumulative distribution of the percentage reached 90% of the corresponding particle size; D (4,3) volume or mass average particle size;Second, the commonly used particle size measurement method(1) sieving method(2) sedimentation method (gravity sedimentation method, centrifugal sedimentation method)(3) resistance method (Kurt particle counter)(4) Microscope (image) method(5) Electron microscopy(6) ultrasonic method(7) breathable method(8) laser diffraction methodAdvantages and disadvantages of various methodsSieve method: Advantages: simple, intuitive, low cost of equipment, commonly used in samples larger than 40μm. Disadvantages: can not be used for 40μm fine sample; results by human factors and sieve deformation of a greater impact.Microscope: Advantages: simple, intuitive, can be morphological analysis. Disadvantages: slow, poor representative, can not measure ultra-fine particles.Sedimentation method (including gravity settlement and centrifugal settlement): Advantages: easy to operate, the instrument can run continuously, low price, accuracy and repeatability is better, the test range is larger. Disadvantages: test time is longer.Resistance method: Advantages: easy to operate, the total number of particles can be measured, the equivalent concept clear, fast, good accuracy. Disadvantages: the test range is small, easy to be blocked by particles, the media should have strict electrical characteristics.Electron microscopy: Advantages: suitable for testing ultrafine particles or even nano-particles, high resolution. Disadvantages: less sample, poor representation, the instrument is expensive.Ultrasonic method: Advantages: direct measurement of high concentrations of pulp. Disadvantages: low resolution.Ventilation method: Advantages: instrument prices are low, do not have to disperse the sample, magnetic particles can be measured powder. Disadvantages: can only get the average particle size, can not measure the particle size distribution.Laser method: Advantages: easy to operate, fast test, test range, repeatability and accuracy, and can be measured online and dry. Disadvantages: the results affected by the distribution model, the higher the cost of the instrument.Third, the basic principle of laser particle size analyzerLaser diffraction technology began in the small angle scattering, so this technology also has the following name:Fraunhofer diffraction method(Approximately) positive light scattering methodSmall angle laser scattering method (LALLS)At present, this range of technology has been expanded to include light scattering within a wider range of angles, in addition to the approximate theory such as Fraunhofer diffraction and irregular diffraction, and the Mie theory is now used by instrument manufacturers Theory as one of the important advantages of its products.Mickey’s theory is named after a German scientist. It describes the uniform spherical particles in the uniform, non-absorbing medium and its surroundings in the space of the radiation, the particles can be completely transparent or can be completely absorbed. The Millerian theory describes that light scattering is a resonance phenomenon. If a specific wavelength of the beam encounters a particle, the particle produces an electromagnetic vibration at the same frequency as the emitted light source – irrespective of the wavelength of the light, the particle diameter, and the refractive index of the particles and the medium. The particles are tuned and received at a specific wavelength, and the energy is re-emitted within a particular spatial angular distribution as well as a relay. According to the Mie theory, it is possible to produce multiple oscillations of various probabilities, and there is a certain relationship between the cross section of the optical action and the particle size, the wavelength of light and the refractive index of the particles and the medium. If you use the Mie theory, you must know the refractive index and absorption coefficient of the sample and the medium.Fraunhofer theory is named after a German physicist, Franco and Fader, which is based on scattering at the edge of the grain and can only be applied to completely opaque particles and small angles of scattering. When the particle size is less than or equal to the wavelength, the Fraunhofer assumption that the extinction coefficient is constant is no longer applicable (it is an approximation of the Mie theory, that is, ignoring the Mi’s theory of imaginary subsets and ignoring the light scattering coefficient and Absorption coefficient, that is, all the dispersant and dispersive optical parameters are set to 1, the mathematical treatment is much simpler, the color of the material and small particles are also much larger error. The approximate Mickey theory is not applicable to the emulsion ).The laser particle size analyzer is based on the phenomenon of light diffraction, when the light through the particles when the diffraction phenomenon (its essence is the interaction of electromagnetic waves and substances). The angle of the diffracted light is inversely proportional to the size of the particle.Different sizes of particles through the laser beam when the diffraction light will fall in different positions, the location information reflects the particle size; the same large particles through the laser beam when the diffraction light will fall in the same position. The information of the diffracted light intensity reflects the percentage of particles of the same size in the sample.The laser diffraction method uses a series of photodetectors to measure the intensity of the diffracted light at different angles of the particle size of the particle, using the diffraction model, through the mathematical inversion, and then the particle size distribution of the sample.And the diffracted light intensity received by the position detector gives a percentage content of the corresponding particle size.The dependence of the intensity of the diffracted light on the particles decreases with the decrease of the particle size. When the particles are as small as several hundred nanometers, the diffraction intensity is almost completely dependent on the angle, that is, the diffracted light at this time Distributed in a wide range of angles, and the light intensity per unit area is very weak, which increases the difficulty of detection.The measurement of samples under 1um and wide particle size ranges (tens of nanometers to several thousand micrometers) is the key to the laser diffraction granulator. In general, the following techniques and optical path configurations are used:1, multi-lens technologyThe multi-lens system was widely adopted before the 1980s, using a Fourier optical path configuration, where the sample cell was placed in front of the focusing lens and equipped with a number of different focal lengths of the lens to accommodate different particle size ranges. The advantage is simple design, only need to be distributed in the tens of degrees range of focal plane detector, the cost is low. The disadvantage is that if the sample size is wide when the need to replace the lens, the results of different lenses need to be split, for some unknown particle size of the sample with a lens measurement may lose the signal or due to process changes caused by changes in sample size can not be timely reflect.2, multi-light technologyMulti-light source technology is also used in the Fourier optical path configuration that the sample cell in front of the focusing lens, generally only distributed in the range of tens of degrees angle detector, in order to increase the relative detection angle, so that the detector can receive small particles Diffracting the optical signal, and disposing the first or second laser at different angles relative to the optical axis of the first light source. The advantage of this technique is that it is only a detector that is distributed over several tens of degrees, and the cost is low. The measurement range, especially the upper limit, can be wide. The disadvantage is that the small area detector distributed in the small angle range is also used for small Particle measurement, due to the small particles of diffracted light in the unit area of the signal is weak, resulting in small particles when the signal to noise ratio is reduced, which is why the multi-light source system in the measurement range of more than 1500 microns or so, to ensure that a few microns The following small particles of accurate measurement, the need to replace the short focal length of the focus lens. In addition, the multi-lens system in the measurement of samples, the different lasers are turned on, and in the dry measurement, because the particles can only pass through the sample pool, only one light source can be used for measurement, so the general use of multi-lens technology The lower limit of the dry size is less than 250 nm.3, multi-method hybrid systemMulti-method hybrid system refers to the laser diffraction method and other methods of mixing design of the particle size analyzer, laser diffraction part of the distribution only a few tens of degrees range of the detector, and then supplemented by other methods such as PCS, generally a few microns The above is measured by laser diffraction, and particles below a few microns are measured by other methods. Theoretically, the lower limit of the particle size depends on the lower limit of the auxiliary method. The advantage of this method is that the cost is low and the overall measurement range is wide, The best measurement conditions required by the method, such as the concentration of the sample are not the same, are often difficult to balance, and in addition to the systematic error between the different methods, it is often difficult to obtain the desired result in the data fitting area of the two methods unless It is known that the particle size of the sample only falls within the range of the diffraction method or within the range of the auxiliary method. In addition, the multi-method mixing system requires two different sample cells, which is not a problem for wet measurement because the sample can be recycled, but the sample can only be circulated through the sample cell for a dry process, Method of simultaneous measurement, so a variety of methods mixed system in the dry measurement of the lower limit of the particle size can only be hundreds of nanometers.4, non-uniform cross-wide compensation for wide-angle detection technology and anti-Fourier optical systemThe wide-angle detection of non-uniform cross-wide area compensation and the anti-Fourier optical system are developed in the late 1990s. The anti-Fourier optical path configuration is used to place the cell behind the focusing lens, In a very wide range of angles, the general physical detection angle of up to 150 degrees, so that a single lens to measure tens of nanometers to several thousand microns of the sample possible, optical schematic diagram shown in the design of the detector On the use of non-uniform cross and with the increase in the size of the detector area also increased the arrangement, both to ensure that the resolution of large particles when the measurement also ensures a small particle detection signal to noise ratio and sensitivity. No need to replace the lens and other methods can be measured from tens of nanometers to several thousand microns of particles, even the dry measurement, the lower limit can reach 0.1 microns. The disadvantage of this approach is that the cost of the instrument is high relative to the previous methods.The laser beam emitted from the laser is focused by a microscope, pinhole filter and collimator collimation, into a parallel beam of about 10 mm in diameter, the beam is irradiated onto the particles to be measured, a portion of the light is scattered, Leaf lens, the radiation to the radio and television detector array. Since the radio and television detector is on the focal plane of the Fourier lens, any point on the detector corresponds to a certain scattering angle. The array of radio and television detectors consists of a series of concentric rings, each of which is a separate detector capable of linearly converting the scattered light projected onto the above into a voltage and then sending it to a data acquisition card which converts the electrical signal Zoom in, after the A / D switch to the computer.Now the actual structure of the laser particle size instrument has played a great change, but the same principle.At present, people have come to the following conclusions: (1) measuring less than 1mm of particles, you must use the Mie theory;(2) measuring more than 1mm particles, if the lower limit of measurement of the instrument is less than 3mm, the instrument still use the Mie theory, or in the particle size distribution of 1mm near the “out of nothing” a peak;(3) The laser particle size analyzer can use the diffraction theory of the conditions: the lower limit of measurement of the instrument is greater than 3mm, or the measured particles are absorbent type, and the particle size is greater than 1mm;(4) As a universal laser particle size analyzer, as long as the lower limit of measurement is less than 1mm, whether it is used to measure large particles or small particles, should use the Mie theory.Fifth, the composition of laser particle size analyzerA light source (usually a laser) is used to produce a monochromatic, coherent and parallel beam; the beam processing unit is a beam amplifier with an integrating filter that produces a beam of expanded, near-ideal light beams to illuminate the dispersed particles (A coherent strong light source with a fixed wavelength, a He-Ne gas laser (λ = 0.63um).Particle disperser (wet and dry)Measure the scattering spectrum of the detector (a large number of photodiodes)Computer (for controlling equipment and calculating particle size distribution)Through technological advances, the lower limit of measurement can be 0.1um, some up to 0.02umSix, test operation steps1, preparation of equipment to install and disperse the liquid (gas)2, sample inspection, preparation, dispersion and sample concentration check the particle size range and particle shape and whether the full dispersion;3, measurement (select the appropriate optical model)4, the error from the diagnostic system of measurement error (deviation), can come from the incorrect sample preparation, deviation from the theoretical assumptions of the particles and / or due to improper operation and operation of the instrument caused;Seven, commonly used laser particle size meter manufacturersBritish Malvern laser particle size analyzer (abroad)Europe and the United States grams of laser particle size analyzer (Zhuhai)Dandong laser particle size analyzer (Liaoning)Eight, the test object1. All kinds of non-metallic powder: such as tungsten, light calcium, talc, kaolin, graphite, wollastonite, brucite, barite, mica powder, bentonite, diatomaceous earth, clay and so on.2. All kinds of metal powder: such as aluminum powder, zinc powder, molybdenum powder, tungsten powder, magnesium powder, copper powder and rare earth metal powder, alloy powder.3. Other powder: such as catalyst, cement, abrasive, medicine, pesticide, food, paint, dyes, phosphor, river sediment, ceramic raw materials, various emulsions.
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【introduction】The construction of flexible electronic devices with certain functions and structures provides a variety of possibilities for human life in the future, such as wearable electronic products, implantable chips, sensing skin, flexible robots, and so on. With the deepening of the research on luminescent materials, these creative products are moving from the laboratory to people’s lives. For example, a clothing containing a light-emitting element, a detector built by an optical signal, a chip capable of releasing a drug through an optical signal, a chip that participates in a signal transmission, and the like. Early research, mainly using screen printing technology, to achieve a large-scale manufacturing of AC flexible luminescent materials. Nowadays, with the advent of 3D printing technology, flexible materials with more complex structures are also produced.The researchers have designed a novel structure of light-emitting devices, which are mainly composed of four parts, namely, a pair of parallel stack or side by side distribution of the electrode, light-emitting layer, dielectric layer and a controllable electrode layer. The control of the electrode layer is achieved by selecting a different polarizing material or an electroconductive thin film. This new structure is not only simple, but also conducive to large-scale manufacturing, more importantly, compared with the traditional sense of the light-emitting devices, a pair of opposing electrodes are no longer stacked with each other, but side by side distribution. It is because of this structural advantage, the researchers have designed different types of devices. For example, this flexible material is mounted on an umbrella, and when the water falls on an umbrella, the umbrella glows, which also makes it possible to build a remote detector that utilizes optical signal changes.Figure 1. Comparison of conventional sandwich configurations of light emitting devices (denoted as S-ELS) and polarized electrode bridge light emitting devices (denoted PEB-ELS)a) Schematic diagram of the structure of a conventional sandwich device (S-ELS)b) Schematic diagram of polarization electrode bridge light emitting device (PEB-ELS)c) Flexible display of PEB-ELS;d) The backside of the PEB-ELS is enlarged with an electrode width of 0.45 mm and a pitch of 0.40 mm.e) the water shines on the PEB-ELS;f) Comparison of changes in AC voltage before and after water dumping.Figure 2. Effect of bridging material, voltage and frequency on PEB-ELS performancea) PEB-ELS positive partial magnification, electrode width of 1.5 mm, spacing of 0.4 mm;b) the addition of different bridging liquid, the light in the dark situation;c) the relationship between the luminous intensity and the type and concentration of the bridged liquid at a voltage frequency of 2 kHz;d) the effect of substrate impedance on the luminous intensity, insert the picture shows the relationship between liquid contact time and luminous intensity;e) the relationship between the luminous intensity and the voltage frequency when the voltage is constant;f) Draw a Picasso painting on PEB-ELS with a pencil.Figure 3. Polarized electrode bridge experiment.a-b) bridging the experimental diagram, the first PEB-ELS is divided into two parts, and then use the hydrogel as a polarized bridge, the two parts connected to test;c) half of the PEB-ELS infiltrated in the two beakers;d) Transparent polyacrylamide hydrogel for bridging, 5 cm long, 1.6 cm wide, 0.3 cm thick;e) After the two beakers are connected with a hydrogel, the voltage is applied and the PEB-ELS emits light;f) Place the hydrogel directly on PEB-ELS and the material glows.Figure 4. Preparation and performance testing of rainwater sensorsa-b) rainwater sensor preparation diagram;c-d) rainwater sensor of the physical map, white and dark;e) hand as bridge electrode, PEB-ELS light;f) When the water is frozen, the emission intensity of PEB-ELS is weakened.【summary】This study presents a new, low-cost, flexible, light-emitting device that can be mass-produced. In this paper, the luminescence performance of the device is studied, and the relationship between the luminescence performance and the bridging material and the applied voltage is discussed. And then made it based on the optical signal sensor. When the umbrella is wet or touched by hand, the contact surface will light. Not only that, this new type of light emitting device can also be used to write, when writing with a pencil, the corresponding area can also light. This also provides a new possibility for the future development of touch display technology.
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