R／S构型双环己基酯类手性液晶的合成与性质

以４（４’烷基反环己基）环己烷甲酸为原料，经过构型转换及分离得到４（４’烷基反环己基）反环己烷甲酸，用马钱子碱拆分２辛醇，合成了Ｒ、Ｓ两种构型的二个系列八种新型手性液晶化合物，用ＩＲ、ＭＳ、ＮＭＲ及元素分析确定了它们的结构，用ＤＳＣ和偏光显微镜确定了这些化合物的相变温度和相态，讨论了手性分子的构型对液晶性质的影响。     

共析成分Zn-Al合金的相变内耗和DSC的研究

利用低频内耗和示差扫描量热计（ＤＳＣ）等技术研究了共析成分Ｚｎ－Ａｌ合金共析转变过程中的能量耗散问题，发现相变潜热和热滞均与相变的路径有关。相变内耗峰的峰高与频率倒数之间呈非线性关系，而对数减缩量与频率例数之间呈线性关系。证明了共析转变过程的内耗不仅具有滞弹性的性质，而且具有线性粘弹性的性质，相变内耗峰主要是线性粘弹性内耗的贡献。用Ｍａｘｗｅｌ模型对实验结果进行了解释。     

共析成分Zn—Al合金的相变内耗和DSC的研究

利用低频内耗和示差扫描量热计（ＤＳＣ）等技术研究了共析成分Ｚｎ－Ａｌ合金共析转变过程中的能量耗散问题，发现相变潜热和热滞均与相变的路径有关，相变内耗峰的峰高与频率倒数之间呈非线性关系，而对数减缩量与频率例数之间呈线性关系，证明了共析转变过程内耗不公具有粘滞弹性的性质，而且具有线性粘弹性的性质，相变内耗峰主要是线性粘弹性内耗的贡献，用Ｍａｘｗｅｌｌ模型对实验结果进行了解释。     

非晶态PdCuSi的内耗和DCS研究

用葛摆测量了ａ－ＰｄＣｕＳｉ合金的内耗－温度曲线，证明在该合金的Ｔｇ和Ｔｘ温度附近有两个内耗峰Ｐ１和Ｐ２．Ｐ２峰是与非晶晶化有关的内耗峰，而Ｐ１峰可能是弛豫型的内耗峰，分析了倒扭摆和Ｃｏｌｌｅｔｔｅ摆的灵敏度，阐述了这责任中摆不适用于测量ａ－ＰｄＣｕＳｉ类合金的内耗峰。     

非晶态PdCuSi的内耗和DSC研究

用葛摆测量了ａ－ＰｄＣｕＳｉ合金的内耗－温度曲线，证明在该合金的Ｔｇ和Ｔｘ温度附近有两个内耗峰Ｐ１和Ｐ２．Ｐ２峰是与非晶晶化有关的内耗峰，而Ｐ１峰可能是弛豫型的内耗峰．分析了倒扭摆和Ｃｏｌｌｅｔｔｅ摆的灵敏度，阐述了这两种摆不适用于测量ａ—ＰｄＣｕＳｉ类合金的内耗峰．     

聚(酰亚胺-酯)热致性液晶高分子的合成与表征EI

以Ｎ，Ｎ′－二（ω－羟乙基）苯均四甲酰二亚胺和４，４′－（α，ω－烷亚甲基二酰氧）苯甲酰氯为单体，通过溶液缩聚反应合成了含不同柔性链长的主链型液晶高分子。聚合物的液晶行为用ＤＳＣ、偏光显微镜和Ｘ衍射法进行了表征。发现所有的聚合物均有较好的结晶性和随分子中柔性链段长度的改变聚合物的相变温度呈规律性的变化。     

苯乙烯／马来酸酐共聚物的氢键诱导液晶体

制备了以苯乙烯／马来酸－４－羧基酚酯共聚物为质子供体,苯乙烯基吡啶为质子受体的氢键诱导液晶复合物。用ＤＳＣ和ＰＯＭ研究二者复合并后的液晶行为。结果表明,４ＳＺ含量在３０－７０％的复合物表现为向列相液晶态,其中等摩尔比的复合物的热稳定性提高。     

聚硅氧烷侧链高分子液晶的表征

合成了以４－烯丙氧基苯甲酸－４＇－甲基基苯酚酯及烯丙基胆甾醇醚单独或同时作为液晶基元的侧链聚硅氧烷液晶。用偏光熔点仪、ＤＳＣ和Ｘ射线衍射分析，对侧链聚硅氧烷液晶的液晶性及其受热相转变行为进行了研究，讨论了它们的液晶性和热转变行为与结构的关系。     

手性近晶C(Sc*)相串型液晶共聚酯的合成与表征

以２,５－二「４－（Ｓ）－２－甲基丁氧基（苯甲酰氧基」对苯二酚,４,４′－二羟基－,α,ω－二苯氧丁烷和对苯二甲酰氯为单体,采用溶液共缩聚的方法。合成了一系列新的手性近晶Ｃ（Ｓｃ＊）相串型液晶共聚酯,单体的结构通过元素分析、ＩＲ、＾１Ｈ－ＮＭＲ和ＭＳ等方法确证,共聚物通过ＧＰＣ、ＤＳＣ、ＴＧ、ＷＡＸＤ、偏光显微镜和旋光仪等方法表征,发现所有共聚物加热至各自的熔点以上都能形成液晶态,在液晶态可以观察     

高聚物的DSC相变曲线的模拟

研究了从ＤＳＣ相变曲线计算相变转化率和转化率对时间的一阶导数的二阶导数的样条函数方法。结果表明，用样条函数模拟ＤＳＣ相变曲线可适用于各种高聚物及多重相变峰，并具有较高的精度．     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...