用Zn掺杂和热处理改善SnS薄膜的电学特性

用质量比为1%∶0.2%(质量分数)的Sn、S混合粉末在玻璃衬底上热蒸发沉积SnS薄膜,氮气保护下对薄膜进行350℃、40min热处理后,得到简单正交晶系SnS多晶薄膜,薄膜的电阻率为103Ω.cm,选择2%和4%(质量分数)的Zn掺杂来改善SnS薄膜的导电性。研究表明,SnS∶Zn薄膜最有效的热处理条件为300℃、40min,掺Zn后薄膜的物相结构转为简单正交和面心正交晶系混合相,SnS∶Zn薄膜(2%和4%(质量分数))的电阻率在1.8528×10-3～4.944×10-4Ω.cm之间,导电类型为N型。薄膜中Sn和S分别呈+2和-2价,Zn显示+2价,以间隙和替位两种状态存在于SnS中,对薄膜导电性起改善作用的是间隙态的Zn离子。     

Zn掺杂SnS薄膜的表征及光学特性

真空共蒸发制备掺Zn(2%,4%(质量比))的SnS薄膜。研究热处理对Zn掺杂SnS薄膜的结构、表面形貌、化学组分及光学特性的影响。实验给出2%掺Zn薄膜经300℃,40 min热处理后,得到正交晶系的SnS多晶薄膜。掺Zn可一定程度抑制薄膜中S的损失,使薄膜体内Sn∶S元素化学计量得到改善,从未掺Zn的Sn∶S比为1.90∶1降到1.38∶1(2%)及1.36∶1(4%)。掺Zn后SnS薄膜的吸收边都发生红移,光吸收系数高达105cm-1。未掺Zn薄膜的直接光学带隙1.95 eV,掺Zn是1.375 eV(2%)和1.379 eV(4%)。Sn和S在薄膜中分别呈+2和-2价态,Zn以间隙和替位两种状态存在。     

Zn掺杂Sn2S3薄膜的特性

高纯Sn和S粉按1∶0.41%(质量分数)配比,均匀掺入9%(质量分数)的高纯Zn粉,单源共蒸发沉积薄膜后再进行热处理,得到Sn2S3∶Zn薄膜。XRD分析显示,380℃,55min热处理得到简单正交晶系的纯Sn2S3薄膜。掺Zn 9%(质量分数)的薄膜经370℃热处理15min得到的薄膜仍属简单正交晶系。掺Zn后Sn2S3薄膜的表面均匀和致密性变好,平均晶粒尺寸从未掺Zn时的35.69nm增加到58.80nm。Sn2S3薄膜的导电类型均为N型,掺Zn后薄膜的电阻率为60.5(Ω·cm),比未掺杂时降低1个数量级。Sn2S3薄膜的直接光学带隙为1.85eV,本征吸收边为551nm;Sn2S3∶Zn 9%(质量分数)薄膜的光学带隙1.41eV,本征吸收边873nm发生红移,Sn2S3薄膜的光吸收系数均达到105cm-1。     

Sb掺杂Sn2S3薄膜的表征及电学特性

真空蒸发制备Sb掺杂Sn2S3多晶薄膜。研究不同比例Sb掺杂对Sn2S3薄膜的电学、结构、表面形貌、化学组分的影响,实验给出掺Sb5%薄膜经380℃热处理30 min可获得结构良好正交晶系的Sn2S3∶Sb多晶薄膜,薄膜的电阻率从未掺杂时的79kΩ.cm降到23.7Ω.cm,下降了三个数量级。Sn2S3薄膜表面为颗粒状,体内化学计量比Sn/S为1∶1.49,与标准计量比非常接近;掺Sb(5%)后为1∶0.543,Sn过量。Sn和S以Sn2+,Sn4+,S2-形式存在于薄膜中;Sb元素显示正5价,部分Sb5+进入晶格替位Sn4+。     

SnS_2纳米薄膜的制备及结构和光学特性

采用真空热蒸发法,在玻璃衬底上制备纳米SnS2薄膜。研究不同Sn和S配比及不同热处理条件对薄膜性能的影响。实验给出采用Sn∶S=1∶1.5摩尔比混合粉末制备的薄膜,经T=430℃,t=40min氮气保护热处理可获得性能良好的SnS2纳米多晶薄膜。薄膜呈n型、表面结构较致密,平均晶粒尺寸为77nm,直接光学带隙约为2.02eV。     

Sb掺杂Sn_2S_3薄膜的制备及光学特性

真空蒸发制备Sb掺杂Sn2S3多晶薄膜(玻璃衬底),研究不同比例Sb掺杂对Sn2S3薄膜的结构、表面形貌、化学组分及光学特性的影响。实验给出5%掺Sb的薄膜经380℃热处理30min(氮气保护)得到正交晶系的Sn2S3∶Sb多晶薄膜,薄膜表面颗粒大小均匀,膜面致密有轻微颗粒聚集现象。薄膜体内Sn与S化学计量比为1∶1.49,掺Sb后为1∶0.543,薄膜中Sn、S、Sb分别以Sn2+、Sn4+、S2-、Sb5+存在。纯Sn2S3薄膜的光透过率在350~500nm波长范围内基本为零,随着波长增大,光透过率增加,其直接光学带隙为2.2eV,吸收边为564nm;掺Sb后薄膜的光透率明显降低,光学带隙为1.395eV比未掺杂时减小0.805eV,吸收边发生红移为889nm。     

Sn2S3薄膜制备及结构与光学特性

采用真空热蒸发法在玻璃衬底上制备Sn2S3薄膜.研究不同Sn和s配比及热处理条件对薄膜的结构及光学特性的影响.结果显示:采用Sn:S为1:1.2(at%)混合粉末制备出的薄膜,在T=430℃,t=40min氮气保护热处理后,可得到结构良好的n型Sn2S3纳米多晶薄膜.薄膜表面致密较平整,颗粒分布均匀,平均晶粒尺寸为60.37m.Sn2S3薄膜的直接光学带隙约为2.0eV.     

热处理对CuInS2薄膜导电类型及光学特性的影响

真空蒸发在载玻片上沉积CuInS2薄膜(Cu、In、S原子配比为1∶0.1∶1.2).摸索CuInS2薄膜发生导电类型转换最有效的热处理条件,研究不同热处理工艺对CuInS2薄膜的结构、表面形貌、化学成分比和光学性能的影响.实验给出:沉积的薄膜进行360℃热处理30 min后,得到黄铜矿结构的CuInS2薄膜;SEN分析显示薄膜表面呈颗粒状较平整致密性略差,导电类型为N型,薄膜的本征吸收限为1.46eV,直接光学带隙Eg=1.38 eV.对薄膜进行370℃热处理20 min同样可得到N型CuInS2但含有少量的CuS2成分,薄膜表面致密性变好但粗糙度增大,本征吸收限发生红移为1.42 eV,Eg=1.40 eV.370℃,30 min热处理后可得到P型CuInS2薄膜,Eg=1.37 eV.制备的三种CuInS2薄膜的光吸收系数都在104 cm-1数量级以上.CuInS2薄膜中In或Cu元素含量大小,对薄膜的导电类型的变化起着决定性的作用,而薄膜中S和In元素的变化直接取决于热处理的条件.     

单源共蒸法制备CuInS2薄膜及特性分析

将单质Cu、In和S粉末按一定比例均匀混合,单源共蒸发沉积CuInS2薄膜.氮气保护对薄膜进行热处理.研究不同热处理条件对薄膜表面形貌、化学组分及电学特性的影响.XRD分析给出直接沉积的CuInS2薄膜为黄铜矿结构,整体性能较差.经400℃、20 min热处理后,CuInS2薄膜特性得到明显的改善,导电类型呈P型,体内元素化学计量比Cu:In:S=1:0.9:1.5接近标准值,Cu含量略多,电阻率为4.8× 10-2 Ω·cm,薄膜的直接光学带隙1.42 eV,光吸收系数105 cm-1.440℃、10 min热处理的薄膜,晶相结构没变但导电类型转为N型,元素化学计量比Cu:In:S=1:2.3:0.8,In元素过量,电阻率为1.3×10-2 Ω ·cm,光吸收系数104 cm-1,直接光学带隙1.39 eV.     

合成Cu_2ZnSnS_4薄膜四元共电沉积机理与退火相转变

采用循环伏安法研究了制备CZTS薄膜四元预制层的电化学沉积机理。结合XRD,SEM,EDS和Raman技术分析预制层退火的相转变机制。结果表明:溶液中Cu2+和Sn2+浓度不仅影响其本身的沉积速率,还影响溶液中其他金属元素的沉积速率,而Zn2+浓度仅影响其本身沉积速率。四元预制层的沉积以原子层外延为机理,在负电位作用下,Cu2+先转变为Cu原子沉积在衬底表面,且与衬底附近析出的S原子发生化学反应,在衬底上生成CuS,同样,SnS和ZnS也以这种方式交替沉积在衬底上。预制层二元硫化物随着退火温度的升高逐渐转变为Cu2(3)SnS3(4)和Cu2ZnSnS4。利用四元共电沉积预制层550℃退火1h合成的Cu2ZnSnS4薄膜原子比为Cu∶Zn∶Sn∶S=23.72∶12.22∶13.07∶50.99。无偏压下合成的CZTS薄膜光电流达到约6nA。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.……     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.