α-Si3N4晶须中缺陷与晶须生长气氛关系的研究

本文研究了用无定形氮化硅超细粉原位生长α-Si₃N₄晶须,晶须生长温度为1400～1450℃,恒温1～4h.讨论了在晶须生长过程中,不同的保护气氛对晶须质量的影响.当晶须在高纯N2气氛中生长时,得到的晶须中氮含量为32%～34%,氧含量为8%～6%,氯含量为0.1%左右.这类晶须中存在着大量的缺陷.当晶须在NH3气氛中生长时,得到的晶须中氮含量为39%左右,氧含量为1%,氯含量为0.01%,在这类晶须的透射电镜照片中几乎看不到缺陷.     

Cl对Si3N4粉中α／β相含量的影响

本文研究了用ＳｉＣｌ４氨解法制备Ｓｉ３Ｎ４粉时，要得到高α相的Ｓｉ３Ｎ４粉的关键，在于必须使系统中杂质氯含量足够低，研究结果表明，在高纯Ｎ２气气氛中制粉，由于系统中氯含量较高，促使粉料中β相含量增高，α相含量降低。而在ＮＨ３气气氛中制粉，由于不断流动的ＮＨ３气，在高温下能携带出残留在粉料中的杂质ＮＨ４Ｃｌ，从而使粉料中的氯含量〈０．０１％，这时制得的粉料，其α相的含量均在９７％以上。     

莫来石晶须制备新工艺与生长机理

本文首次提出了用Ａｌ２Ｏ３－ＳｉＯ２玻璃粉高温热处理制取莫来石晶须的新工艺．采用ＸＲＤ、ＳＥＭ和ＴＥＭ等手段研究了热处理温度制度及气氛对莫来石晶须生长的影响，确定了制备莫来石晶须的最佳工艺参数，所得莫来石晶须的直径为０．４～１．２Ｐｍ、长径比为１０～４０，其生长方向为ｃ轴方向，生成物中莫来石晶须的含量接近９８ｖｏｌ％．探讨了用Ａｌ２Ｏ３－ＳｉＯ２玻璃粉制取莫来石晶须的生长机理．     

氮对纳米硅氮薄膜品化的影响

在电容式耦合等离子体化学气相沉积系统中，用高氢稀释硅烷和氮气为反应气氛制备纳米硅氮（ｎｃ－ＳｉＮｘ：Ｈ）薄膜结果表明：当Ｎ＿２／ＳｉＨ＿４气体流量比（Ｘｎ）从１增加为４时，薄膜的晶态年从５８％降至１４％，晶粒尺寸从１０ｎｍ降至５ｕｍ，Ｎ／Ｓｉ含量比从０．０３增至０．１２．当Ｘｎ≥５，则生成非晶硅氮（ａ－ＳｉＮｘ：Ｈ）薄膜．当Ｘｎ从１增加为１０时，薄膜暗电导率从１０￣（－５）（Ωｃｍ）￣（－１）降至１０￣（－１１）（Ωｃｍ）￣（－１），具有逾渗行为，这与薄膜的晶态率紧密相关．     

氮对纳米硅氮薄膜晶化的影响

在电容式耦合等离子体化学气相沉积系统中，用高氢稀释硅烷和氮气为反应气氛制备纳米硅氮（ｎｃ－ＳｉＮｘ２Ｈ）薄膜，结果表明，当Ｎ２／ＳｉＨ４气体流量比（Ｘｎ）从Ｉ增加为４时，薄膜的晶态率从５８％降至１４％，晶粒尺寸从１０ｎｍ降至５ｎｍ，Ｎ／Ｓｉ含量比从０．０３增至０．１２，当Ｘｎ≥５，则生成非晶硅氮（ａ－ＳｉｕＮｘ２Ｈ）薄膜，当Ｘｎ从１增加为１０时，薄膜暗电导率从１０＾－５（Ωｃｍ）＾－１降至１０＾－     

用纳米非晶Si／N／C粉原位合成Si3N4晶须

采用激光诱导有机硅烷气合成的纳米非晶Ｓｉ／Ｎ／Ｃ粉为原料，在１６００℃，１０１．３ｋＰａＮ２气下，在石墨感应炉中原位制备出α－Ｓｉ３Ｎ４晶须，其直径为０．１－０．５μｍ，长可达几毫米，纯度较高，无过剩碳及金属杂质。     

α－Si_3N_4晶须、晶柱与生长温度关系的研究

本文采用无定形氮化硅超细粉制备α－Ｓｉ_３Ｎ_４晶须和晶柱，并对生长温度对晶须中的缺陷的影响进行了研究。结果表明：晶须生长时能否得到完整的晶体，与其生长温度有关，只有某一温度范围（１４３０℃±３０℃）生长时，才能得到比较完整的晶体，晶须的生长温度太高或太低均会引起晶体生长的不完整性，晶须中会出现大量的缺陷，温度继续升高时，在晶须中又出现了晶粒，继而生长成晶柱。     

磁控溅射Fe-N薄膜的结构和性能

研究了氮流量对磁控溅射Ｆｅ－Ｎ薄膜的磁性和结构的影响．加氮薄膜的软磁性能明显优于纯铁的．当氮的流量为１．０ｍＬ·ｍｉｎ~（－１）时,矫顽力 Ｈ_ｃ达到最小值２０５Ａ／ｍ．当氮流量为０．８ｍＬ·ｍｉｎ_（－１）时,饱和磁化强度达到Ｍ_ｓ＝２．３６Ｔ．在 Ｆｅ－Ｎ薄膜中未发现γ’－Ｆｅ４Ｎ和 α”－Ｆｅ１６Ｎ２．     

碳化硅陶瓷及其复合材料的热等静压烧结研究

本文通过采用热等静压（ＨＩＰ）这一先进的烧结工艺，研究了Ａｌ２Ｏ３添加量对ＳｉＣ陶瓷之显微结构与力学性能的影响。并成功地制备出Ｓｉ３Ｎ４粒子以及ＳｉＣ晶须补强的ＳｉＣ基复合材料，结果表明：Ａｌ２Ｏ３是ＨＩＰ烧结ＳｉＣ陶瓷及其复合材料的有效添加剂，当添加３ｗｔ％Ａｌ２Ｏ３时，采用ＨＩＰ烧结工艺在１８５０℃温度和２００ＭＰａ压力下烧结１ｈ就可获得密度分别高达９７．３％、９９．４％和９７．０％的ＳｉＣ的     

Na_2Mo_（0．1）S_（0．9）O_4（α）－Pr_2（SO_4）_3二元

应用差热分析、Ｘ射线粉末衍射及电测量技术对Ｎａ２Ｍｏ（０．１）Ｓ（０．９）Ｏ４（α）－Ｐｒ２（ＳＯ４）３体系进行了研究，结果表明，在Ｎａ２Ｍｏ（０．１）Ｓ（０．９）Ｏ４相中加入少量的Ｐｒ２（ＳＯ４）３就可以形成完全固熔体，且无任何相变存在，当Ｐｒ２（ＳＯ４）３含量达到４ｍｏｌ％时，电导率较纯Ｎａ２Ｍｏ（０．１）Ｓ（０．９）Ｏ４提高两个数量级（５５３Ｋ时，σ＝１．０９×１０（－３）Ｓｃｍ（－１）），同时还证明了该类导体的导电机理，揭示了电导率与有效空位浓度、掺杂剂浓度及温度之间的依赖关系。     

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.