软段结构对聚酯型聚氨酯结晶性影响的研究

用３种聚酯二醇ＰＥＡ、ＰＢＡ、ＰＨＡ和ＭＤＩ，以溶液聚合法合成了３个系列的线型嵌段聚氨酯胶粘剂（ＰＥＡＵ、ＰＢＡＵ、ＰＨＡＵ）。以Ｘ－Ｒａｙ衍射法测定了３种聚酯和３个系列聚氨酯的结晶度，讨论了聚酯类型、聚酯分子量、聚氨酯中硬段含量等因素对聚氨酯结晶能力的影响。结果表明，在硬段含量不高（＜２５％）情况下，聚氨酯中的结晶部分主要是由聚酯软段引起的，而聚酯结晶能力大小的次序为ＰＨＡ＞ＰＢＡ＞＞ＰＥＡ，增     

含聚二甲基硅氧烷的聚醚聚氨酯膜透气性及表面性质研究

以聚二甲基硅氧烷（ＰＤＭＳ）／聚四氢呋喃（ＰＴＭＯ）为软段，４，４＇－二环己基甲烷二异氰酸酯（ＨＭＤＩ）为硬段（丁二醇ＢＤ为扩链剂）制成的多相嵌段共聚物作为基质材料，进行了气体（Ｏ２和Ｎ２）透过性试验，同时对膜材料进行了ＥＳＣＡ表面分析。结果表明，共聚物膜的透气性能取决于材料中连续相组分，随着软段中ＰＤＭＳ含量的改变而变化。当ＰＤＭＳ含量较高时，共聚物膜显示出ＰＤＭＳ均聚物的特性，具有较高的气体秀     

以聚六亚甲基碳酸酯二醇和聚四亚甲基醚二醇为基的聚氨酯的合成…

以聚六亚甲基碳酸酯二醇（ＰＨＭＣＤ）和聚四亚甲基醚二醇（ＰＴＭＥＧ），４．４’－对二苯基甲烷二导氰酸酯（ＭＤＩ）及１．４－丁二醇（ＢＤＯ）合成线型聚碳酸酯聚氨酯，研究了其软段相的Ｔｇ，力学性能和流变特性。结果表明随ＰＨＭＣＤ含量增大，聚合物的拉伸强度增加，而熔体的表观粘度则降低。     

聚氨酯脲阴离子水分散液

由聚醚（ＰＰＧ）、甲苯二异氰酸酯（ＴＤＩ），二羟甲基丙酸（ＤＭＰＡ）和三乙烯四胺（ＴＥＴＡ）制备不同ＤＭＰＡ和ＴＥＴＡ含量的聚氨酯脲（ＰＵＵ）阴离子水分散液，制备了水分散液浇铸薄膜，研究了硬段和盐基含量对形态和性能的影响。     

以聚六亚甲基碳酸酯二醇和聚四亚甲基醚二醇为基的聚氨酯的合成与性能

以聚六亚甲基碳酸酯二醇（ＰＨＭＣＤ）和聚四亚甲基醚二醇（ＰＴＭＥＧ）、４．４′一对二苯基甲烷二导氰酸酯（ＭＤＩ）及１．４－丁二醇（ＢＤＯ）合成线型聚碳酸酯聚氨酯．研究了其软段相的Ｔｇ、力学性能和流变特性．结果表明随ＰＨＭＣＤ含量增大，聚合物的拉伸强度增加，而熔体的表观粘度则降低     

聚丁二烯聚氨酯弹性体的微相结构与性能

用端羟基聚丁二烯齐聚物（ＨＴＰＢ）作为软段，以甲苯二异氰酸酯（ＴＤＩ），１，４－丁二醇（ＢＤＯ）作为硬段合成了聚氨酯弹性体，用ＦＴ－ＩＲ、ＷＡＸＤ、ＳＡＸＡ、ＤＳＣ和回弹性实验对聚合物的性能进行了表征。结果表明，聚合物具有微相分离的特征，硬段微区尺寸为４０×１０－１０～１００×１０－１０ｍ。受热史对聚合物的玻璃化温度有较大的影响，随着硬段含量的增加而变大。     

聚氨酯对聚氯乙烯粘接机理的研究

用３种聚酯（ＰＥＡ、ＰＢＡ、ＰＨＡ）和ＭＤＩ合成了分子量和软硬段比例大致相同的３种聚氨酯胶粘剂（ＰＥＡＵ、ＰＢＡＵ、ＰＨＡＵ），以ＤＳＣ、ＤＭＡ和相差显微镜等手段研究了它们与ＰＶＣ的相容性。结果表明，ＰＢＡＵ、ＰＨＡＵ与ＰＶＣ均有良好的相容性，而ＰＥＡＵ则与ＰＶＣ不相容。３种胶粘剂对ＰＶＣ的粘接强度差异很大，其粘接强度次序为：ＰＨＡＵ～ＰＢＡＵ＞＞ＰＥＡＵ，由此提出了聚氨酯胶粘剂对ＰＶＣ的粘接机理     

不同种类催化剂对RIM PUU微相分离结构及性能的影响

借助ＤＳＣ、ＥＭ、ＤＭＡ以及拉伸实验等现代测试手段,研究了不同种类催化剂对ＲＩＭＰＵＵ制品微相分离结构及性能的影响。实验结果表明,ＤＢＴＤＬ、ＴＤ和ＵＬ－２９３种催化剂所经的ＲＩＭＰＵＵ体系的微相分离程度有ＴＤ催化体系〉ＵＬ－２９催化体系〉ＤＢＴＤＬ催化体系的趋势,并且ＤＢＴＤＬ的催化效果最佳。可以说,ＤＢＴＤＬ是ＲＩＭＰＵＵ反应体系最理想的催化剂。     

PU软段结构对PU／PMMA IPN中两组分相容性的影响

用同步法合成了４种聚氨酯／聚甲基两烯酸甲酯互穿聚合物网络／（ＰＵ／ＰＭＭＡ ＩＰＮ）利用ＤＤＣ、ＴＥＭ和动态力学谱（ＤＭＳ）等手段综合研究了ＩＰＮ中两组分的相容性和相态结构，用基团贡献加和方法计算了各种ＰＵ和ＰＭＭＡ的溶度参数δ，结合ＰＵ软段链结构讨论了各种ＩＰＮＫ呈现不同相容性和相态结构的原因。     

不同烷氧基取代偶氮染料对聚乙烯基咔唑基复合物光折变性质的影响

合成了不同长度烷氧基取代的偶氮染料：２,５－二甲基－４－（４’－硝基苯基偶氮）苯甲醚（ＤＭＮＰＡＡ）正－丁氧基－２,５－二甲基－４－（４’－硝基苯葵偶氮）苯（ＢＤＭＮＰＡＢ）;正－己氧基－２,５－二甲基－４－（４’－硝苛苯基偶氮）苯（ＨＤＭＮＰＡＢ）。／     

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.     

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...     

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 ...