表面活性剂PVP、CTAB协同效应对制备Cu2ZnSnS4微粒的影响

采用溶剂热法,以CuCl2·2H2O、Zn(Ac)2·2H2O、SnCl4·5H2O作金属源,硫脲作硫源,乙二醇作溶剂,在体系中加入不同表面活性剂PVP和CTAB,研究PVP、CTAB协同效应对制备CZTS颗粒的影响。通过XRD、SEM、UV-Vis方法检测分析CZTS颗粒的物相、结构、形貌以及光学性能。结果表明:所得CZTS颗粒均具有锌黄锡矿结构;当在体系中同时加入PVP、CTAB时,两者的协同效应使得颗粒形貌发生明显变化,光学带隙也发生相应变化;当体系中加入的表面活性剂PVP∶CTAB=3∶1时,合成的颗粒结晶性较好、颗粒形貌为单分散似花状微粒、光学带隙为1.48 eV,与太阳能电池所需的最佳带隙接近。最后,提出了相应的机理。     

原位热硫化法制备Cu_3SnS_4纳米薄膜及其光学性质

采用化学水浴法(CBD)制备了Cu_3Sn纳米薄膜,通过原位热硫化法制备了Cu_3SnS_4纳米薄膜。分别采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)与X射线能谱仪(EDS)分析了样品的组成、结构与形貌。采用紫外-可见分光光度计(UV-Vis)测试了Cu_3SnS_4样品的光学性质。结果表明,样品物相纯净、形貌均一,Cu3Sn纳米薄膜由球形纳米颗粒组成,Cu_3SnS_4纳米薄膜由片状纳米颗粒组成,Cu_3SnS_4薄膜样品在紫外-可见光区有良好的吸收性质,其光学带隙为1.70eV,适合作为太阳能电池吸收层。     

纳米ZnO镶嵌SiO2薄膜的光学特性研究

采用射频反应磁控溅射法在玻璃衬底上成功制备出纳米ZnO镶嵌SiO2非晶薄膜,利用X射线衍射仪、场发射扫描电子显微镜、X射线光电子能谱仪和紫外-可见分光光度计研究了纳米Zn0镶嵌SiO2薄膜相比纯ZnO纳米薄膜结构的变化及镶嵌结构对其光学特性的影响.研究发现与纯ZnO纳米薄膜相比,纳米ZnO镶嵌SiO2薄膜结构样品呈非晶结构,在紫外区光吸收系数以及光学带隙明显增大,光吸收以及光学带隙的变化与样品制备的衬底温度有关.研究结果表明,由于SiO2的特殊结构实现了对纳米ZnO的束缚,减少了ZnO纳米粒子的集聚,使得量子限制效应变得显著,导致复合膜光学带隙的明显增大以及吸收边的蓝移.     

纳米Si薄膜光学性质和弹性常数的研究

采用基于密度泛函理论的第一性原理的方法,对厚度为0.54～3.30nm纳米Si薄膜的电子结构、光学性质及弹性常数进行了计算。结果表明,纳米Si薄膜是直接带隙半导体材料;随着纳米Si薄膜厚度的减小,带隙逐渐增大;薄膜的光学吸收边发生蓝移,吸收带出现宽化现象;弹性常数、杨氏模量和泊松比呈现尺寸效应。     

Cu2ZnSnS4薄膜光电性能及其太阳电池的制备和研究

采用硫化Zn/Sn/Cu金属多层膜的方法制备了太阳电池吸收层用的Cu2ZnSnS4(CZTS)薄膜。用X射线衍射仪、拉曼光谱仪、紫外-可见近红外分光光度计、扫描电镜、能谱仪及数字源表等对薄膜进行了一系列的表征。结果表明制备的CZTS薄膜没有杂相存在并具有标准拉曼峰。薄膜在可见光范围内的吸收系数>104cm-1,同时其光学带隙接近1.5eV。CZTS薄膜具有均匀致密的表面形貌,薄膜元素比例非常接近标准化学计量比。此外,CZTS薄膜呈现显著的光电流响应性能,其光电流的激发和衰减时间分别为0.0736和0.2646s。     

溶剂热法制备Cu2ZnSnS4粉末及其表征

采用溶剂热法, 以CuCl₂·2H₂O、Zn(Ac)₂·2H₂O、SnCl₄·5H₂O作金属源, 硫脲作硫源, 乙二醇作溶剂, PVP作表面活性剂, 制备了Cu₂ZnSnS₄(CZTS)粉末。利用XRD、SEM、Raman、TEM、EDS、UV-Vis吸收光谱探讨了反应温度和反应时间对制备CZTS粉末的相结构、成分、形貌以及光学性能的影响。结果表明: 反应温度和反应时间对CZTS粉末的颗粒形貌和光学性能影响较大, 最佳合成温度为230℃, 反应时间24 h。该条件下生成的CZTS粉末相较为纯净、结晶完全, 形貌为表面嵌有薄片的微球, 各元素原子比接近化学计量比, 光学带隙为1.52 eV, 与太阳能电池所需的最佳带隙接近。并对其形成机理进行了初步探讨。     

Cu2ZnSnS4纳米颗粒及其薄膜的制备与表征

采用热注入法,在油胺(OLA)中合成出Cu2ZnSnS4(CZTS)纳米颗粒,并在玻璃衬底上制备了薄膜,研究了不同合成温度对纳米颗粒生成的影响.通过X射线衍射仪、拉曼光谱仪、透射电子显微镜、扫描电子显微镜、紫外可见分光光度计对所得纳米晶材料的结构与成分、颗粒大小与形貌、光吸收谱进行了测试分析.研究结果表明:采用热注入法的最佳合成温度在260℃左右,该温度下生成的多晶CZTS纳米颗粒尺寸约10 nm,分散性良好,光学禁带宽度约1.5 eV.     

溶剂的溶解度对CZTS颗粒性能影响的研究

通过溶剂热法,以含有PVP的醇类作溶剂,以CuCl_2·2H_2O、Zn(Ac)_2·2H_2O、SnCl_4·5H_2O作金属源,硫脲作硫源,在一定条件下反应,通过XRD、Raman、SEM、EDS、TEM、UV-Vis以及电化学分析系统研究醇类溶剂溶解度对CZTS颗粒的物相、结构、形貌以及光电性能的影响。结果表明:所选溶剂溶解度不同,对得到的CZTS颗粒的结晶性、形貌、原子比以及光电性能均有相应的影响;当选择溶解度为32.1的乙二醇作溶剂时,合成的颗粒结晶性较好,颗粒形貌为表面嵌有薄片的微球,颗粒表面缺陷形态为贫铜富锌结构,光学带隙为1.47 e V,与太阳能电池所需的最佳带隙接近,薄膜电阻率为45.86Ω·m。     

退火处理对Y2O3薄膜结构和光学性能的影响

采用射频磁控溅射法以Y2O3陶瓷为靶材在单晶si(Ⅲ)和石英表面制备了Y2O3薄膜.利用X射线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外-可见(UV-VIS)光谱仪和傅立叶变换红外(FTIR)光谱仪对真空退火前后Y2O3薄膜的结构和光学性质进行了分析研究.结构研究表明,在200℃条件下制备的Y2O3薄膜为非晶态,经600℃退火后出现单斜相,经800℃退火后薄膜完全转化为立方多晶,同时得到了不同晶面的晶粒尺寸;沉积态的Y2O3薄膜由球状颗粒排列组成,经800℃真空退火后薄膜为柱状晶.光学性质研究发现,真空退火后Y2O3薄膜的红外透过率显著下降;使用Tauc作图法得到不同结晶条件下的光学带隙,发现薄膜的光学带隙与结晶条件有关,并且退火后薄膜的光学带隙明显减小.     

Cu_2ZnSnS_4纳米晶及其薄膜的制备

以乙酰丙酮铜(Cu(AcAc)2)、乙酸锌(Zn(CH3COO)2·2H2O)、氯化亚锡(SnCl2·2H2O)、升华硫(S粉)和十二硫醇为原料,用热注射法合成了Cu2ZnSnS4(CZTS)纳米晶。再将Cu2ZnSnS4纳米晶制成胶体墨水,用旋涂法制备出Cu2ZnSnS4薄膜。用X射线衍射(XRD)仪、拉曼光谱(RS)仪、透射电镜(TEM)、扫描电镜(SEM)、X射线能量色散谱仪(EDS)和紫外-可见光谱(UV-Vis)分光光度计对CZTS纳米晶及薄膜的晶体结构、微观形貌、化学组成及光学性能进行表征,研究了注射温度对纳米晶结构、形貌、晶粒大小以及化学组成的影响以及热处理时间对Cu2ZnSnS4薄膜结构、形貌、化学组成和光学性能的影响。结果表明,在注射温度为180℃时合成的CZTS纳米晶为锌黄锡矿结构,平均粒径为18 nm。在500℃热处理2 h所制备出的薄膜,在可见光范围内其吸收系数高达104cm-1,禁带宽度为1.45 eV。     

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.……     

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.……     

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 ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.