含邻苯二甲腈侧基的聚酰胺的合成与热行为

合成了一种新型的含邻苯二甲腈基团的二胺4-（2,4-二氨基苯氧基）邻苯二甲腈（CNDA）,将它与苯甲酰氯和间苯二甲酰氯反应,分别合成了溶解性能良好的酰胺模型化合物（b-CNPA）和酰胺聚合物（m-CNPA）,并分别在265℃和275℃对它们进行热固化反应。热重分析（TGA）,差示扫描量热分析（DSC）和红外光谱（FT-...     

N-(苯并环丁烯-4-基)马来酰亚胺的制备及热稳定性

对N-(苯并环丁烯-4-基)马来酰亚胺原有文献的合成方法进行了改进,在温和条件下使该单体产率有所提高。研究了该单体分别与苯乙烯和N-苯基马来酰亚胺在溶液中的二元共聚反应,对所得的共聚物进行表征,并对其热性能进行了分析。结果表明,N-(苯并环丁烯-4-基)马来酰亚胺的均聚物具有很高的热分解温度,初始分解温度为400℃,480℃的热失重仅为10%,将其与苯乙烯共聚可显著提高苯乙烯的耐热性,有望用于高性能复合材料的树脂基体。     

侧基含马来酰亚胺基团聚苯醚的合成与表征

低介电常数(ε_r)和介电损耗因子(tan δ)特性的聚苯醚(PPO)是制造高频覆铜板的理想材料,但因其缺乏可交联的活性基团而限制了在覆铜板领域的工业应用。文中采用N-溴代琥珀酰亚胺(NBS)对PPO进行溴化,得到溴化率为15%的溴化聚苯醚(BrPPO)。基于Diels-Alder(DA)反应,利用呋喃对马来酰亚胺进行保护,并与BrPPO反应,成功合成了侧基修饰马来酰亚胺基团的改性聚苯醚(MPPO),赋予了PPO可交联的活性位点。利用核磁共振氢谱、傅里叶变换红外光谱、差示扫描量热分析(DSC)和热重分析(TGA)对产物的结构进行了表征。DSC分析表明,MPPO在164℃时存在脱除呋喃的吸热峰,在320℃时存在马来酰亚胺双键交联的放热峰。TGA分析表明,MPPO前期失重率为9.5%,马来酰亚胺基团含量为11.4%。采用MPPO制备的覆铜板其介电性能、耐热性及尺寸稳定性都有所提升。     

一种含马来酰亚胺苯并噁嗪的合成及性能

以4-氨基苯基马来酰亚胺、甲醛、苯酚为原料,采用两步法经中间产物三嗪(TMIPT)合成苯并噁嗪(MIPB),并借助红外光谱(FT-IR)、核磁共振(1H-NMR)和元素分析(EA)等手段对产物MIPB进行了表征。通过差示扫描量热(DSC)、FT-IR和热重分析(TGA)对MIPB的热行为进行了研究,结果发现,MIPB化合物的熔点为113.3℃,相比于Ishida报道的MIB化合物147℃的熔点降低了33.7℃,MIPB在150℃的固化率大大增加,固化后的MIPB树脂5%热失重温度T5为348℃,10%热失重温度T10为368℃,800℃残炭率达到55.6%。     

含马来酰亚胺和烯丙基醚的苯并(口恶)嗪的合成与性能

合成了3-(4-烯丙氧基)苯基-3,4-二氢-6-(N-马来酰亚胺)-1,3-苯并噁嗪(AMB),用FT-IR、1H-NMR和EA对其结构进行了表征。与传统的3-苯基-3,4-二氢-(N-马来酰亚胺)-1,3-苯并噁嗪(MIB)相比,AMB的分子结构中多了一个烯丙基醚基团。AMB可溶于丙酮、甲醇、氯仿、四氢呋喃等普通有机溶剂,熔点115℃。用DSC和TGA对AMB和MIB的热聚合行为进行了比较,发现烯丙基醚官能团引入后的AMB熔点更低;于氮气条件下,150℃热处理AMB,可大幅度地降低热处理产物的再次热聚合温度,从而使其在相对低的温度下(150℃~200℃)得到充分的固化;AMB固化产物的热稳定性比MIB更好,5%热失重温度(T5)从375℃上升到449℃,800℃残炭率从56%上升到65%。     

含羟基自加速固化酞菁树脂的结构及热行为

利用4-硝基邻苯二甲腈的亲核取代反应合成了6种邻苯二甲腈衍生物。FT-IR1、H-NMR、DSC和TGA对化合物的结构和热性能进行了表征。带羟基邻苯二甲腈类衍生物在高温区都存在自加速热聚合行为,其自加速热聚合活性与羟基和邻苯二甲腈单元的比例密切相关,且羟基比例越高,反应活性越强。     

含二氮杂萘酮结构聚芳酯的合成及其在绝缘漆中的应用

以二酸4-[4-(4-羧基苯氧基)苯基]-2-(4-羧基苯基)二氮杂萘-1-酮(Ⅰ)与4,4'二羟基二苯丙烷进行溶液缩聚反应合成了一种含有二氮杂萘酮结构的聚芳酯,采用FT-IR,1H NMR对其结构进行了表征,利用差示扫描量热仪(DSC),热重分析仪(TGA)研究了聚芳酯的热性能.结果表明所合成的聚芳酯具有高的玻璃化转变温度(227℃),在氮气气氛中5%的热失重温度高于455℃.聚芳酯可溶解于N-甲基吡咯烷酮(NMP),N,N-二甲基乙酰胺(DMAc),氯仿等多种溶剂,该类聚芳酯制成的绝缘漆,具有机械强度高,柔韧性和附着力好,以及良好的电绝缘性能.     

N-(苯并环丁烯-4-基)马来酰亚胺的Diels-Alder反应及聚合物热稳定性

对N-(苯并环丁烯-4-基)马来酰亚胺(NBCBMI)单体在热引发下发生的Diels-Alder反应进行了初步探索,研究了该单体和苯乙烯(St)及N-苯基马来酰亚胺(NPMI)的自由基共聚物分别与NPMI发生的Diels-Alder反应,并对聚合物结构进行了表征分析。通过热重分析研究了Diels-Alder反应前后聚合物热稳定性的变化。结果表明,聚合物DANBCBMI初始分解温度约为500℃,600℃的热失重仅为32.21%,比NBCBMI自由基聚合产物PNB-CBMI的热稳定性有显著提高,而共聚物在发生Diels-Alder反应后的溶解性下降,但热稳定性有一定提高。     

含氟-吡啶环聚酰亚胺的合成与性能

用4-苯基-2,6-双[3-(4-氨基-2-三氟甲基苯氧基)苯基]吡啶(m,p-6FPAPP)作为二胺,3,3′,4,4′-二苯酮四甲酸二酐(BTDA)及2,2-双[4-(3,4-二羧基苯氧基)苯基]丙烷二酐(BPADA)作为二酐,以N,N-二甲基甲酰胺(DMF)为溶剂,通过常规的两步法,合成了可溶性含氟聚酰亚胺。用FT-IR、DSC、TGA、UV-vis、溶解性和吸水率测试对聚合物的结构和性能进行了表征。结果表明,FT-IR测试在1780 cm-1、1720 cm-1和1380 cm-1左右出现了聚酰亚胺的特征吸收峰。所得聚酰亚胺在常见溶剂(如间甲酚,DMF,N,N-二甲基乙酰胺(DMAc),二甲基亚砜(DMSO),N-甲基吡咯烷酮(NMP),四氢呋喃(THF))中可溶解;在氮气氛中,玻璃化转变温度(Tg)为202.1℃~219.7℃,10%失重温度为537.0℃~572.8℃,800℃质量保持率为60.7%~63.1%。PI膜的紫外截止波长为375 nm~380 nm,吸水率为0.55%~0.63%。     

改性双马来酰亚胺树脂体系的固化工艺及热稳定性研究

采用差示扫描量热仪 (DSC)对价格低廉、配比不同的二苯甲烷型双马来酰亚胺(BMI) /二烯丙基双酚A(BA) /N -苯基马来酰亚胺 (NPMI)三元共聚树脂体系反应性能、反应动力学进行研究 ,确定了固化工艺。对固化树脂的热变形温度、热失重及耐湿热性能进行了分析。     

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.     

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