Sol—Gel法制备Y系高温超导材料及烧结条件的研究

介绍了ＹＢａ２Ｃｕ３Ｏ７－δ和Ｆ掺杂的ＹＢａ２Ｃｕ３Ｆ０．６Ｏ７－δ高Ｆｃ超导材料的Ｓｌｏ－Ｇｅｌ法制备，并对烧结条件进行了研究。     

溶胶凝胶法制备YBa_2Cu_3O_（7－δ）超细粉体及其性质

用柠檬酸盐强的螯合作用，可以制得钇、钡、铜稳定的配位化合物，由溶胶－凝胶法使其转变成Ｙ＿２Ｏ＿３、ＢａＣＯ＿３、ＣｕＯ超微细粉的均匀混合物、９３０℃下制得单一相的ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－δ）粉体，粒径约１００ｎｍ。对ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－δ）合成反应的动力学进行了研究，对溶胶凝胶法制得的ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－δ）超细粒子进行的测定表明，其粒度、纯度、烧结性和超导性能形成上都比固相合成反应为优。     

Y－Ba－Cu－O熟粉和生粉与油酸化学作用的研究

采用ＣＮＤＯ／２量子化学计算方法，研究了Ｙ－Ｂａ－Ｃｕ－Ｏ熟粉及生粉的化学成键特征。计算表明，ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－δ）高温超导相形成后，其中各化学键发生变化，化学键的反应活性趋于平均化。因此，Ｙ－Ｂａ－Ｃｕ－Ｏ熟粉可以与油酸发生均匀化学反应，得到的膏状物能用来焊接高ＴｃＹＢＣＯ超导线材及器件。     

涂层与薄膜

２０００１２０１ 原位退火时磁控溅射Ｎｄ１Ｂａ２Ｃｕ３Ｏ７－δ薄膜的影响——Ｍｏｒｉ Ｚ．Ｔｈｉｎ Ｓｏｌｉｄ Ｆｉｌｍｓ,１９９９,３５４（１～２）：１９５（英文） ＮｄＢａ２Ｃｕ３３Ｏ７－δ（ＮＢＣＯ）薄膜经原位退火后,薄膜质量得到改善。用单靶直流磁控溅射方法在 ＭｇＯ（１００）上制备 ＮＢＣＯ薄膜,沉积后将薄膜冷却至室温,然后在４００ＰａＯ２气氛中,将沉积室温升高至３５０－６００℃,保温０．５～８０．０ ｈ。经此处理后,薄膜的超导性能以及电阻率、粗糙度明显改善。原位退火后可提高薄膜Ｃ轴向零电阻温度…     

Sol—Gel法制备YBa2Cu3O7—δ—Agx复合超导材料的显微结构与性能

研究采用Ｓｏｌ－Ｇｅｌ法制备ＹＢ２Ｃ３Ｏ７－δ－Ａｇｘ复合超导材料的显微结构与性能的关系，Ａｇ的加入能使ＹＢａ２Ｃｕ３Ｏ７－δ相晶粒细化，结晶度提高，致密度增加，晶界无序区域变窄，这些都有利于材料性能的提高，但过多的加入Ａｇ则导致材料性能下降。对Ａｇ的作用机理作了初步探讨。     

高温超导YBa2Cu3O6＋x的氧扩散与其电子结构的正电子湮没研究

报告了ＹＢａ２Ｃｕ３Ｏ６＋ｘ超导体制备工艺中不同氧扩散条件下的正电子实验研究。发现即使对同组分，除烧结温度不同外，其它实验条件保持完全相同的样品，其Ｃｕ－Ｏ链区电子结构可能也存在差异。讨论了氧扩散与其电子结构的关联，证明高温超导ＹＢａ２Ｃｕ３Ｏ６＋ｘ存在最佳氧扩散条件或最佳烧结温度区域。     

用Monte-Carlo法对制备Y_1Ba_2Cu_3O_(7-δ)超导薄膜过程的模拟

本文利用蒙特卡洛方法对Ｙ１Ｂα２Ｃｕ３Ｏ７－δ超导薄膜制备过程中， Ｙ、Ｂａ、Ｃｕ的溅射和沉积过程进行了模拟，得到了按各种角分布溅出的Ｙ、Ｂａ、Ｃｕ三种原子的沉积粒子数随Ｒ，ｚ的变化规律，并通过计算结果与实验结果的比较初步确定了Ｙ、Ｂａ、Ｃｕ三种原子在被溅出时的角分布。     

Sb2O3掺杂对YBa2Cu3O7—δ超导性质的影响

研究了Ｓｂ２Ｏ３掺杂的多晶ＹＢａ２Ｃｕ３Ｏ７－δ超导体的超导转变温度和输运临界电流密度Ｊｃ（Ｂ）在磁场中的行为。测量了超导性能对该掺杂浓度的依赖关系。适当浓度的掺杂可使Ｊｃ至少提高一个数量级，对掺杂样品进行了扫描电镜微结构观测和Ｘ射线结构分析。     

Cu—YBaCuO粉末复合材料组织与性能的研究

预期得到了一种具有较高强度而又不降低导电率的铜基粉末复合材料，选用超导陶瓷粉末ＹＢａＣｕＯ为强化相，以冷等静压，热挤压等粉末冶金方法研制了两种（Ｃｕ－５％ＹＢａＣｕＯ）和Ｃｕ－２０％ＹＢａＣｕＯ粉末复合材料，在常温和液氮温度下测试了这两种复合材料的力学性能与导电性能，研究表明，该复合材料的力学性能与导电性能，研究表明，该复合材料低温（７７Ｋ）时的力学性能优于室温，但导电率并没有改善，其原因在于所加     

YBCO中氧原子近邻结构的温度相关性的EXAFS研究

运用定向ＥＸＡＦＳ（ＥⅡａ）技术对高温超声材料ＹＢａ２Ｃｕ３Ｏ７－δ在不同温度下氧原子的Ｋ吸收边进行了分析，获得了材料温度从７７Ｋ到１０５Ｋ的ＥＸＡＦＳ信息，发现在整个变化过程中，Ｏ－Ｃｕ原子对的平均间距未发生改变，但表征其键长有效涨落的德拜－瓦勒因子有一个稳定的增长.     

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.