共缩聚型可溶性聚酰亚胺的合成与性能研究(3)

以４,４′－二（４－氨基苯氧基）二苯砜及４,４′－二氨基二苯醚或４,４′－二氨基二苯甲烷为共缩聚二胺单体与二苯醚３,３′,４,４′－四甲酸二酐缩聚并经化学亚胺化合成了共缩聚型聚酰亚胺。当共缩聚二胺单体中４,４′－二（４－氨基苯氧基）二苯砜／４,４′－二氨基二苯甲烷和４,４′－二（４－氨基苯氧基）二苯砜／４,４′－二氨基二苯醚的摩尔比分别为１０∶０～５∶５及１０∶０～３∶７时,所得聚酰亚胺可溶于强极性溶剂。可溶性聚酰亚胺的玻璃化转变温度（Ｔｇ）在２５５～２６５℃,并随结构中４,４′－二（４－氨基苯氧基）二苯砜的摩尔比上升而略有下降。聚酰亚胺在Ｎ２中的热降解起始温度在５５５～５９０℃,并且与二胺单体的结构及比例基本无关。     

共缩聚型可溶性聚酰亚胺的合成与性能研究(Ⅱ)

采用３，３′－二甲基－４，４′－二氨基二苯甲烷，４，４′－二氨基二苯醚或４，４′－二氨基二苯甲烷为共缩聚二胺单体与二苯甲酮３，３′，４，４′－四酸二酐进行缩聚制备共缩聚型聚酰亚胺。当３，３′－二甲基－４，４′－二氨基二苯甲烷与４，４′－二氨基二苯醚的摩尔比为１００～８２或３，３′－二甲基－４，４′－二氨基二苯甲烷与４，４′－二氨基二苯甲烷的摩尔比为１００～７３时，所得聚酰亚胺可溶解于强极性有机溶剂。所得可溶性聚酰亚胺在ＮＭＰ中的特性粘度在０．６２～０．８０ｄＬ／ｇ。它们在氮气中的热降解起始温度在５３０℃左右，并且在研究范围内与共聚二胺的结构及比例无关。     

主链含长柔性链的聚酰亚胺的合成与性能研究

以α,ω－二（４－氨基苯氧基）ｎ烷与六氟叉丙基二－（３,４－邻葳二甲酸酐）缩聚并经化学亚胺化合成了主链含长柔性链的聚酰亚胺。该类聚酰亚胺在ＤＭＡ、ＤＭＦ、ＮＭＰ、ＴＨＦ、间甲酚氯仿中有很好的溶解性,且与柔性链的长度无关。     

共缩聚型可溶性聚酰亚胺的合成与性能研究（II）

采秀３，３′－二甲基－４，４′二氨基二苯甲烷，４，４′－二氨基二苯醚或４，４′二氨基二苯甲烷为共缩聚二胺单体与二苯甲酮３，３′，４，４′－四酸二酐进行缩聚制备共缩聚型亚胺，当３，３′－二甲基－４，４′二氨基二苯甲烷与４，４′－二氨基二苯醚的摩尔比为１０：０～８：２或３，３′二甲基－４，４′－二氨基二苯甲烷与４，４′－二氨基二苯甲烷的摩尔比为１０：０～７：３时，所得聚酰亚胺可溶解于强极性有机溶剂，所     

PET－PBT共聚酯的结构与结晶性能

用差示扫描量热法（ＤＳＣ）、核磁共振技术（ＮＭＲ）以及红外光谱等方法对经共缩聚而制得的ＰＥＴ－ＰＢＴ共聚酯进行了结构和性能分析。ＰＥＴ－ＰＢＴ共聚酯为嵌段共聚物，两种链段的非晶区是相溶的，只观察到１个玻璃化转变温度Ｔｇ，而它们的晶相是分离的。随着ＰＥＴ－ＰＢＴ共聚酯中ＰＢＴ链段含量提高，共聚结晶熔点不断下降，Ｔｇ也有下降趋势。ＰＢＴ链段的引入增强了ＰＥＴ分子链段的柔顺性，有利于提高ＰＥＴ链段的结晶能力。另一方面，少量ＰＢＴ链段的引入，也破坏了ＰＥＴ分子链的规整性，不利于其结晶。由于这两方面的原因，在低ＰＢＴ链段含量时，ＰＥＴ－ＰＢＴ共聚酯的结晶能力改善并不十分明显。     

共缩聚醚酯聚酰胺亚胺的合成和性能研究

用对－氨基苯甲酸酯封端的聚（四次亚甲基）醚（ＡＰＴＭＯ），４，４－二氨基二苯酰胺（ＤＡＢＡ）及均苯四甲酸二酐（ＰＭＤＡ），利用溶液聚两步法合成了一系列不同硬段含量的共缩聚醚酯聚酰胺亚胺。用动态力学分析（ＤＭＡ）、示差扫描量热（ＤＳＣ）研究了样品的热性能和相态结构，用热重分析（ＴＧＡ）和应力－应变试验测定了材料的热稳定性能和力学性能。结果表明，共缩聚醚酯聚酰胺亚胺具有两相结构，有良好的力学性能和热稳     

共缩聚型可溶性聚酰亚胺的合成与性能研究（1）

采用，３，３′－二甲基－４，４′－二氨基二苯甲烷，４，４′－二氨基二苯醚或４，４′－二氨基二苯甲烷为共缩聚二胺单体与二苯醚３，３′－，４－４′四酸二酐进行缩聚型聚酰亚胺。当３，３′－二甲基－４，４′二氨基二苯甲烷与４，４′－二氨基二苯醚的摩尔比为１：０￣４：６或３，３′－二甲基－４，４′－二氨基二苯甲烷与４，４′－二氨基二苯甲烷的摩尔比在１０：０￣５：５时，所得聚酰亚胺可溶解于强极性有机溶剂。所得     

含二氮杂萘结构聚醚砜酮酮的合成及表征

以１，４－二（４－氯代苯甲酰基）苯及４，４＇－二氯二苯砜单体与４－（４－羟基苯基）－２，３－二 氮杂萘－１－酮单体经来核取代反应，合成了一系列分子主链中含有Ｃ－Ｎ键的杂环聚醚砜酮酮三元共聚物 ＰＰＥＳＫＫ，用 ＦＴ－ＩＲ、１Ｈ－ＮＭＲ、ＤＳＣ、 ＴＧＡ、 Ｘ射线衍射等方法对共聚物进行了表征，结 果表明，ＰＰＥＳＫＫ为具有高热稳定性的可溶性无规共聚物，巨随着砜基比例的增加，共聚物玻璃化温度 逐渐升高     

ANDPO/BMI共聚物的研究

利用未见文献报道的氨基二苯醚树脂（ＡＮＤＰＯ）与４，４′－二氨基二苯甲烷双马来酰亚胺（ＢＭＩ）共聚，研究了预聚体系的溶解性、溶液的稳定性，用ＴＧＡ、ＤＳＣ研究了固化物的耐热性，结果表明，预聚体系在低沸点，弱极性溶剂如丙酮、１，２－二氯甲烷中具有较好的溶解性，预聚体固化后表观分解温度ＴΛ可达３８０℃以上，耐温指数Ｔｚｇ在２２０℃左右。     

含稠杂环结构聚芳醚酮的合成与表征

以无水ＡｌＣｌ３／ＣｌＣＨ２ＣＨ２Ｃｌ／ＤＭＦ为催化剂／溶剂体系,将（夹）二氧蒽（ＯＤＰ）和吩噻恶（ＯＳＰ）分别与对苯二甲酰氯、间苯二甲酰氯及２,５－二氯对苯二甲酰氯进行亲电缩聚,合成了几种主链含稠杂环结构的聚芳醚酮,用ＩＲ、ＤＳＣ、ＴＧ和ＷＡＸＤ等方法对其进行了分析,研究表明,它们均属非晶态聚合物,其对数比浓粘度均在０．６５以上,具有很高的玻璃化温度（Ｔｇ＝１９０～２５８℃）、优异的耐热性和耐溶     

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 ...