Li-N-H共掺法制备 p型 ZnO薄膜

采用Li-N-H共掺技术在玻璃衬底上生长p型ZnO薄膜．XRD结果表明共掺ZnO薄膜具有高度c轴取向,Hall测试表明薄膜的电阻率为25．2Ω·cm,Hall迁移率为0．5cm~2/(V·s),空穴浓度为4．92×10~(17)/cm~3．此外,p-ZnO薄膜在可见光区域具有90%的高透射率．     

铝氮共掺制备p型ZnO薄膜的电学性能研究

本文通过直流反应磁控溅射,采用Al N共掺的方法在N2O-O2气氛下制备p型ZnO薄膜.结果表明,衬底温度为500 ℃时共掺所得p型ZnO的载流子浓度最高,并且比单独掺氮时高近3个数量级.本文还讨论了生长气氛对薄膜电学性能的影响,当衬底温度为500 ℃时,在纯N2O气氛下制备的p型ZnO的空穴浓度最高,为7.56×1017 cm-3,同时薄膜的电阻率和载流子的迁移率分别为94.3 Ω*cm和0.09 cm2V-1s-1.     

SiO2/Si衬底制备ZnO薄膜及表征

本文报道了利用脉冲激光沉积技术在热氧化p型硅衬底上生长ZnO外延薄膜.引入高阻非晶SiO2缓冲层,有效地降低了检测过程中单晶衬底对ZnO薄膜的电学性能影响.利用XRD,SEM,Hall和PL对其进行研究.结果表明,在衬底温度为500℃时,生长的ZnO薄膜具有优良的晶体质量,电学性能和发光性能.     

Al、N共掺杂实现ZnO的p型转变及其掺杂机理探讨

利用直流反应磁控溅射以Al、N共掺杂的方法生长p-ZnO薄膜.ZnO薄膜沉积于具有不同衬底温度的玻璃或Si衬底上,N来自NH3与O2的生长气氛,Al来源于AlxZn1-x(x=0.08%)靶材.利用XRD、XPS、Hall测试对其性能进行了分析.结果表明,用Al、N共掺杂的方法可以得到c轴择优取向的p型ZnO薄膜,载流子浓度为(1014～1015) cm-3,电阻率为(1.54～3.43)×103 Ω·cm,迁移率为(1.16～4.61) cm2/V·s.由Al、N共掺杂和仅掺N的两种情况下ZnO薄膜的N1s的XPS图谱可以推断出,N的掺入可能是以Al-N键的形式存在,而且Al的存在促进了N原子作为受主的掺入.     

掺杂ZnO薄膜研究

采用电子束蒸发方法在玻璃衬底上制备ZnO薄膜和掺杂ZnO薄膜.通过X射线衍射、台阶仪及Hall效应等测试研究了衬底温度和掺杂对晶体质量和电学性能的影响,发现原位生长的ZnO薄沿c轴择优生长,且掺杂ZnO薄膜具有低达3.029×10-4Ω·cm的电阻率.     

喷雾热解法生长N掺杂ZnO薄膜机理分析

通过超声喷雾热解工艺,以醋酸锌和醋酸铵的混合水溶液为前驱溶液,在单晶Si(100) 衬底上制备了N掺杂ZnO薄膜,采用热质联用分析(TG—DSC—MS)、X射线衍射(XRD)、场发射扫描电镜(FESEM)和霍耳效应(Hall-effect)测试等手段研究了喷雾热解工艺下N掺杂ZnO薄膜的生长机理、晶体结构和电学性能.结果表明,随衬底温度的不同,薄膜呈现出不同的生长机理,从而影响薄膜的晶体结构和电学性能.在优化的衬底温度下,实现了ZnO薄膜的p型掺杂,得到的p型ZnO薄膜具有优异的电学性能,载流子浓度为3.21×10¹⁸cm^-3,霍耳迁移率为110cm²·V^-1s^-1,电阻率为1.76×10^-2Ω·cm.     

离子注入法制备N掺杂p型ZnO薄膜

采用离子注入技术对射频磁控溅射制备的ZnO薄膜进行N掺杂,通过退火实现了ZnO薄膜的p型转变.利用X射线衍射(XRD)和Hall实验对样品热退火前后的性能进行了研究.实验数据表明,该掺杂方法能得到稳定的p型ZnO薄膜,其电学性能随热退火温度的升高和时间的延长而进一步改善,其中在950℃、7min退火条件时,载流子浓度为1.68E 16cm-3,电阻率为41.5Ω·cm.     

化学溶液沉积法制备的Bi_4Ti_3O_(12)铁电薄膜的电学性能研究

采用化学溶液沉积工艺在电阻率为 6～ 9Ω·cm的n -Si(10 0 )衬底上生长Bi4Ti3O1 2 铁电多晶膜 ,研究了薄膜的电学性能 ,结果表明在 6 50℃下退火 1h得到的Bi4Ti3O1 2 薄膜具有良好的介电和铁电性能 ,其介电常数ε =12 9,剩余极化Pr=5.1μC/cm2 ,矫顽电场Ec=96kV/cm。     

Na掺杂含量对ZnO:Na_x薄膜结构和光电性能的影响

利用激光脉冲沉积法(PLD)制备了Na掺杂ZnO∶Nax薄膜(0≤x≤0.1),并较全面地研究了Na含量对ZnO∶Nax薄膜结晶质量和光电性能的影响。研究结果表明Na含量低于5%时,ZnO∶Nax薄膜能够保持良好的c轴择优取向生长。随着Na含量的增加,薄膜由本征n型转变为p型。并且当Na含量为2%时,获得p型性能良好的薄膜:电阻率为53.5Ωcm,迁移率为0.55cm2V-1s-1,空穴浓度为2.1×1017cm-3。结合XPS测试结果,我们认为p型转变是因为Na掺杂在ZnO中主要形成受主态NaZn。PL测试表明ZnO∶Na0.0 2薄膜在377nm处具有良好的室温紫外带边发射。     

Al、N共掺Zn1-xMgxO薄膜的制备与性能研究

采用直流反应磁控溅射方法,由氨气和氧气的混合气体在玻璃和单晶硅衬底上制备Al、N共掺Zn1-xMgxO薄膜.采用XRD、FE-SEM、Hall实验、UV-VIS透射谱以及EDS等方法对共掺Zn1-xMgxO薄膜的结晶性能、电学和光学性能进行研究.结果表明薄膜有明显的C轴择优取向,玻璃衬底上制备的p-Zn0.9Mg0.1O薄膜的电阻率为8.28 Ω穋m,空穴浓度和迁移率分别为1.09×1019 cm-3和0.069 cm2/V穝.并且掺Mg的ZnO薄膜透射光谱表现出明显的蓝移.p-Zn0.9Mg0.1O/n-Si异质结的I-V特性曲线表现出明显的整流特性,可以确定制备的Al、N共掺Zn0.9Mg0.1O薄膜的导电类型是p型的.     

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.