电子束蒸发制备的铟锡氧化物薄膜及其光电性质

用电子束蒸发技术制备出3000-5000A厚,透明导电的锢锡氧化物(ITO)薄膜。这种薄膜的薄层方块电阻是4.5-20Ω/口,在波长为700A时,透光率是80-95％。用x-射线衍射分析测定了薄膜的形貌,测算出它的颗粒度为1-3μ。通过Hall效应测定出薄膜的载流子厚度(N)是3.9×10~(-9)CM~(-3),霍耳迁移率是94cm~2V~(-1)S~(-1),电阻率(P)是4.0×10~(-4)-2×10~(-3)·cm。测得的Hall电压是负值。这说明它是一种n型半导体,与热探针法测得的结果一致。用光学方法计算出薄膜的E_g是3.4ev,该薄膜在制备半导体光伏器件中进行了试用。     

0.08Pb(Fe1/3Sb2/3)O3-yPbTiO3-(1-0.08-y)PbZrO3压电陶瓷性能研究

合成了钙钛矿结构的0.08Pb(Fe1/3 Sb2/3)O3-yPb-TiO3-(1-0.08-y)PbZrO3三元系压电陶瓷材料,测量并计算了不同y值时的压电常数(d33)、机电耦合系数kp、k33)、机械品质因数(Qm)以及极化前后的介电常数(εT33/ε0),对实验现象进行了简单的讨论,得出一些有益的结论;实验结果表明当选取合适的y值时可以获得压电性能良好的压电材料,如y=0.45时材料的平面机电耦合系数kp、纵向机电耦合系数k33和压电常数d33分别达到0.64×10-12C/N、0.72×10-12C/N和365×10-12C/N.     

35kV、11O/3~(1/2)kV工频电压比例标准的建立和传递方法的研究

本文介绍35kV和110/3~(2╱1)kV工频电压比例标准的建立及其传递方法。它们采用电容分压器的结构,在低电压下用感应分压器校准,在高电压下使用。研究结果表明,这一工频电压比例自校传递系统的测量准确度,对于35kV╱100V变化为1.5×10~(-5),对于(110/3~(2╱1)kV)/(100/3~(2╱1)V)为5×10~(-5)。     

用粘度法测定半乳甘露聚糖的分子量和分子链构型参数

本文从市售田菁粉中分离出半乳甘露聚糖,经纯化分级后得到分子量从1.78×10~3到9.8×10~3的七个级分。用粘度法、小角光散射法和广角激光光散射法测定了各个级分在水中25℃时的[η]、M_(?)、A_2和R_g,得到它们与分子量的关系为[η]=1.88×10~(-2)M~(-0.3),A~2=3.55×10~(-3)M~(-0.65),R_g=4.70×10~(-2)M~(0.56);利用[η]/M~(1/2)=φ(r_o~2/M)~(3/2)+BM~(1/2)求得r_o~2/M=0.0145(nm~2);利用R_g~2/M=R-(gO)~2/M+K(R_(gO)~2)~5/2 M~2/R_g~3求得R_(gO)~2/M=0.0067(nm~2),α=0.518M~(0.06);利用Yamakawa-Fujii-Bohdanecky的蠕虫型圆柱体模型求得:M_2=457(nm~(-1)),(r_o~2/M)_∞=0.0167(nm~2)λ~(-1)=7.63(nm),ρ=3.82(nm),d=0.82(nm),L=2.19×10~(-3)M,C_∞=14.8,证明半乳甘露聚糖的主链略带刚性,但比三硝基纤维素柔软,可以用蠕虫状模型处理。     

液晶／聚合物复合膜的性能及其富氧效果

随着高分子材料科学的飞跃发展,人们期望着Po_2、αo_2/N_2值均优良的膜材料出现。液晶/聚合物复台膜首先由日本科学家KAJIYAMA使用苄叉类液晶与PVC(聚氯乙烯)共混后制成二元复合膜,Po_2达5.75×10~(-10)cm~3·cm·cm~2·sec~1·cmHg~1、αo_2/N_2达到2.95。清华大学化学系王良御、杨诚用苯基环乙烷类液晶与PVC共混制成的复合膜在北京氧气厂试验时Po_2达到134.7×10~(10)cm~3·cm·cm~2·sec~1·cmHg~1,α达到4.45,普通空气经过分离后可以得到含O_2 42％的富O_2空气。实际分离系数α’o_2/N_2=2.27。通过对不同含O_2量的原料气的渗透试验证明,复合膜的α’对浓度不同的原料气有不同的值。     

聚酰亚胺箔式电阻应变片的制造

聚酰亚胺箔式电阻应变片在国外已经普遍作为高精密级电阻应变片使用。这是因为用作应变片基底材料的聚酰亚胺粘合剂具有以下几个特性: 1.优良的电性能:体积电阻1.4×10~(16)欧姆·厘米,表面电阻2.8×10~(14)欧姆,介电常数3.34,介电损耗1.44×10~(-2),因此有很高的绝缘电阻。 2.很好的粘接性能。即使在250℃高温下     

标准电池检定规程中的误差分析

根据标准电池的特性可知,在标准电池的整个使用期间,外界温度变化几乎是引起误差的主要来源(当然还有振动、充放电等)。这不仅是由于标准电池的电动势—温度系数比较大(为-40μV/℃),而且由于其每个支管的温度系数分别为-350μV/℃和+310μV/℃,几乎比整只电池的温度系数大一个数量级,因此控温和测温是检定电池最应重视的。标准电池电动势与温度的关系表达式为: E_(?)=E_(20)+α(t-20)×10~(-6)+β(t-20)~2×10~(-6) (1)     

高T_c超导化合物YBa_2Cu_3O_(6.5+δ)的Gibbs生成自由能

用 CaF_2单晶作固体电解质,构成了氟化物-氧化物原电池(?)及(?)测得电池的可逆电动势为E_1=-0.063+1.43×10~4×T(V)E_2=0.089+1.68×10~(-4)×T(V)从而计算了由纯氧化物生成 BaCuO_2(011相)及 YBa_2Cu_3O_(6.5(?)δ)(123相)的标准生成自由能变化:△G_(011)~0=-10.5+1.8×10~(-3)×T(×4186.8J/mol)△G_(123+δ)~0=-19.0+(7.4-1.6×δ)×10~(-3)×T(×4186.8J/mol)在计算△G_(123+δ)~0时考虑了氧的非化学计量系数δ。     

尖晶石/玻璃复合材料的制备和性能研究

采用电子陶瓷工艺制备了一系列玻璃/尖晶石陶瓷复合材料,结果表明:复合材料的介电常数、热膨胀系数和显微硬度随着尖晶石含量的增加而增加,而且材料中硼酸铝的生成对复合材料的介电和热膨胀性能有一定影响。所制备的复合材料具有低的介电常数(5.5~6.5)、低的热膨胀系数(5.3×10-6~5.5×10-6℃-1)和低的烧结温度(≤1000℃),有望用于先进的微电子封装基板材料。     

梯度复合KTN薄膜的铁电和热释电性能研究

在Pt/Ti/SiO2/Si基片上采用Sol-Gel法制备了五组分成分梯度分布的KTa1-xNbxO3(x=0.55,0.525,0.50,0.425,040)热释电薄膜。测试结果表明,复合KTN薄膜具有钙钛矿型结构,0.5μmKTN薄膜在15℃至51℃温度范围内,频率1.0kHz时,平均相对介电常数εr=1075,平均介电损耗tanδ=0.011。在室温及120kV/cm下极化30m in后,0.5μm复合薄膜在15-51℃温度范围内热释电系数出现峰值,平均热释电系数为3.54×10-6C/(cm2.K),电压响应优值Fv=1.205×10-9C.cm/J,探测度优值Fd=3.768×1-7C.cm/J。该薄膜工作温度范围较宽,作为热释电材料开发应用前景十分广阔。     

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.