金刚线切割多晶硅片表面减反射绒面的制备

为解决金刚线切割多晶硅片表面制绒的问题,提出了一种创新的两步腐蚀制备硅表面陷光结构的方法。先以浓硫酸作为添加剂去除表面线痕,然后通过酸雾腐蚀法获得一种微米纳米复合的多孔陷光结构。样品在300～1100nm波长范围内的平均光反射率被降至8.6%,减反射效果优良,少子寿命提升0.6μs以上。此方法具有操作简单,无需复杂设备,成本低等优点,易实现工业化生产。     

两步酸修饰的多晶硅绒面结构

本文提出两步法制备多晶硅表面绒面技术,用两次化学腐蚀修饰多晶硅片的表面。实验中首先采用腐蚀液HF/NaNO2/H2O对多晶硅表面进行腐蚀,然后采用腐蚀液HF/HNO3/（NH4）2C2O4/H2O对其表面进一步修饰。通过多晶硅SEM表面形貌图分析,两步法修饰的多晶硅表面有形状如蚯蚓状的腐蚀坑,腐蚀坑的深度和分布密度相对较大。通过反射谱分析了多晶硅片表面陷光效果,并与用其它方法修饰的硅表面陷光效果进行了对比,与传统配方HF/HNO3/H2O获得的多晶硅表面相比,综合平均反射率下降了7%左右。这种方法获得的多晶硅表面能有效收集太阳光,有利于提高太阳能电池的转换效率。     

单晶黑硅微结构对其反射率影响的研究

采用Ag辅助化学腐蚀法在不同H2O2浓度、腐蚀温度和腐蚀时间条件下制备了单晶黑硅微结构,并系统地研究了这种微结构对表面反射率的影响规律。采用场发射扫描电子显微镜对样品形貌进行了观察,并利用分光光度计对样品的表面反射率进行了测试,最终采用陷光模型对黑硅微结构与其反射率的关系进行了深入分析。发现当腐蚀液为7.8mol/L HF和0.6mol/L H2O2混合液、腐蚀温度为20℃以及腐蚀时间为90s时,所制备黑硅的腐蚀深度为900nm,其表面平均反射率为0.98%(400~900nm)。     

一种新型腐蚀剂——醋酸钠溶液对单晶硅太阳电池表面织构化的作用

对晶向为(100)的p型单晶硅片进行表面刻蚀,制作减反射绒面。选用了一种新型的腐蚀剂,即醋酸钠(CH3COONa)溶液,用来腐蚀单晶硅太阳电池。通过分别改变醋酸钠溶液的浓度、温度以及腐蚀时间对硅片表面进行腐蚀发现,经醋酸钠溶液腐蚀后在硅片表面形成腐蚀坑大小适中、分布均匀的绒面结构。在醋酸钠溶液的质量分数为20%、温度为95℃、时间为40min的条件下腐蚀单晶硅片,在波长为700～1000nm之间获得较低的平均表面反射率,且最佳平均反射率为12.14%。从实验结果和成本因素考虑,这种腐蚀剂的成本很低,不易污染环境且重复性好,有利于大规模工业化制绒。     

湿法腐蚀硅片并生长氧化锌纳米棒作为太阳能电池减反层研究

在硅基太阳能电池表面制备减反层可以有效降低硅表面的反射率, 提高吸收率, 从而提高硅基太阳能电池的光电转换效率。本研究利用四甲基氢氧化铵(Tetramethyl Ammonium Hydroxide TMAH)溶液对(100)单晶硅进行各向异性腐蚀, 在表面腐蚀出金字塔结构, 得到了最低为6%左右的反射率。然后采用水热法在该衬底生长氧化锌纳米棒, 得到了最低小于3%的反射率, 比单采用腐蚀或者ZnO纳米棒生长的硅表面的反射率更低。这种减反方法工艺简单、高效, 有望得到应用。     

多晶硅太阳电池表面激光织构工艺研究

采用激光刻蚀,辅以化学溶液腐蚀对多晶硅片进行了表面织构.利用扫描电镜(SEM)、Helios LAB-rc反射率测试仪和Semilab WT2000少子寿命仪对样品进行了表征.结果表明,多晶硅表面经激光织构后表现出很好的陷光效果,反射率降低为8.0％.激光织构使硅片的少子寿命缩短,通过沉积Al2O3钝化薄膜可改善多晶硅片的电学性能.     

氮化硅减反射膜制备工艺对组织结构及折射率影响的研究

太阳能电池是一种清洁能源,近年来发展迅猛。减反射膜能大幅减少太阳能电池对光线的反射,从而提高电池光电转化率。为优化减反射效果,减反射膜设计多样,包括单层膜、双层膜、三层膜和多层膜,膜层不同对薄膜材料的折射率要求不同。氮化硅薄膜是一种优秀的硅基太阳能减反射膜,其折射率在1.78～2.5之间,调控范围广。本文采用脉冲激光沉积法制备氮化硅减反射膜,研究不同工艺参数对硅片上沉积的氮化硅薄膜性能的影响。     

太阳电池组件上纳米多孔SiO_2减反射膜的制备和增透性能研究

采用溶胶-凝胶法制备纳米多孔SiO_2减反射薄膜,通过对不同制备工艺的探索(如陈化时间、提拉速度)以及所制备的纳米SiO_2薄膜的微观结构的研究,探究SiO_2溶胶特性对薄膜结构的影响以及薄膜纳米结构对其光透过率的影响,寻找最优化的制备工艺制备纳米多孔SiO_2减反射薄膜,进一步提高太阳电池组件上超白玻璃的透过率问题. 结果表明以氨水为催化剂、陈化时间为4天、提拉速度为1.25mm/s的工艺制备减反射薄膜效果最好. 在超白玻璃盖板上镀减反射膜后, 透过率 (400～1100nm)由90%提高到96%,对太阳电池组件应用可进一步增加6%左右的可见光利用.     

多孔硅表面氧化钒热敏电阻薄膜的阻温特性

用电化学腐蚀法制备了具有不同导热系数的多孔硅样品(孔隙率为80％±2、厚度为110μm时,导热系数可降低至0．20 W／m·K),并在其表面沉积了氧化钒热敏薄膜,研究了多孔硅样品的热绝缘性能对氧化钒热敏薄膜阻温特性的影响．结果表明:多孔硅良好的热绝缘性使在其表面制备的氧化钒热敏薄膜电阻的灵敏度远高于在硅基底上制备的热敏电阻的(多孔硅和硅片上的氧化钒薄膜电阻随功率变化斜率分别为120 kΩ／μW和2．1 kΩ／μW),且热敏电阻的灵敏度随着多孔硅孔隙率和厚度的增大而升高．     

溶胶-凝胶法制备宽带减反膜

为了克服单层减反射膜剩余反射高，色彩还原性能差的缺点，需要制备宽带减反膜。纳米多孔SiO2薄膜可以实现很好的宽带减反效果。本文用光学薄膜设计程序模拟了光学参数的变化对薄膜光学性能的影响，优化了薄膜的光学参数。实验上通过酸碱两步法和溶胶-凝胶技术制备了折射率梯度的纳米多孔SiO2宽带减反膜。采用椭偏仪、FE-SEM、紫外-可见分光光度计等方法研究薄膜的光学特性和表面形貌。结果表明实验制备的SiO2薄膜具有可控的纳米多孔结构，折射率在1．18～1．43之间可连续调节。形成的宽带减反膜在可见光区域的平均反射率仅为0．44％。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...