UV电磁吸收油墨光聚合动力学研究

目的研究电磁吸收剂的加入对UV光固化体系光聚合动力学的影响。方法采用实时红外光谱技术研究光照强度、光引发剂含量、电磁吸收剂种类及其含量对光聚合动力学的影响。结果光强增加既可以提高聚合体系反应速率,又可以提高最终双键转化率。随着引发剂含量的增加,最终双键转化率从76%提高到100%,但过高的引发剂含量会降低相对反应速率。以氧化石墨烯为电磁吸收剂的油墨最终双键转化率较高,以Fe_3O_4为电磁吸收剂的油墨相对反应速率较高,达到最大相对反应速率时间在10s内。电磁吸收剂含量增大会降低油墨最终双键转化率,对油墨反应速率到达最大值的时间影响不显著。结论光照强度、光引发剂含量、电磁吸收剂种类及其含量对UV电磁吸收油墨光聚合过程均有较大影响。     

温度对自由基聚合几个量的影响

在自由基聚合中,随着温度的变化几个量也随之变化。例如引发剂热分解速率、聚合总速率、动力学链长、稳态时期自由基浓度等。     

环氧单体聚合动力学及体积收缩研究

采用配有水平样品台的实时红外光谱仪(RT-FT-IR)监测三芳基硫金翁盐(UVI-6976和UVI-6992)紫外光引发双酚A型环氧单体(JY-257)光聚合动力学过程,结果表明:配有水平样品台的红外检测动力学得到的数据重现性好;当引发剂UVI-6992的质量分数从0.8%增加到2.3%时,JY-257转化率和聚合速率迅速增加,继续增加引发剂质量分数到5.1%,转化率增加幅度明显减小,且最大聚合速率开始降低;对比两种三芳基硫金翁盐的光引发活性发现,引发剂浓度较低时,UVI-6976的引发活性远远高于UVI-6992;但是当引发剂浓度较高时,二者的引发活性相近;两种引发体系得到的聚合物体积收缩均较低。     

紫外光引发有关单体的聚合研究

采用激光光散射法研究了有关烯类单体的光聚合反应过程，并通过紫外分光光度法标定了丙烯酰胺甲基烯丙基醚的光强～转化率曲线。获得了有关动力学信息，并对单体配比度浓度、引发剂种类及浓度、聚合体系选择及聚合温度环境气氛及紫外光强等因素对光聚合反应的影响进行研究。     

薄膜反应器中UV光引发丙烯酰胺反相乳液连续聚合过程

报道了薄膜反应器在UV光直接引发丙烯酰胺(AM)反相乳液聚合中的应用。以OP-10/Span-80为复合乳化剂,环己烷为溶剂,在室温且不使用引发剂,采用UV光直接引发AM反相乳液聚合,所得聚合物相对分子质量达107。考察了单体浓度、光照强度、液体流量、转速等因素对聚合反应的影响。结果表明,单体浓度增加,聚合物相对分子质量提高,聚合速率先增加后减小;随着光强的增大,单体转化率和聚合速率增加,而聚合物相对分子质量下降;随着转速的增加,单体转化率和相对分子质量先增加后降低,当转速为300 r/min时达到最大值。通过调节转盘转速和原料流量得到最优停留时间。     

1,3—戊二烯阳离子聚合反应动力学

研究了以Ａｌ（ＯＴｆ）３引发的１，３－戊二烯（ＰＤ）在二氯甲烷和正己烷中的阳离子聚合动力学。根据聚合反应引发速度快并呈现转化率不完全的实验事实，提出了快速引发活性中心浓度逐渐降低的非稳态假定，根据这个假定推导出的非稳态动力学方程能较好地与实验数据相吻合。在二氯甲烷中链增长反应速度大于在正己烷中的速度，而链终止反应在二氯甲烷中的速度小于正己烷中的速度，因此在二氯甲烷中聚合反应呈现较高的反应速率及转化     

聚合条件对丙烯酸丁酯反应动力学的影响

采用溶液聚合方法,通过改变聚合条件研究丙烯酸丁酯转化率随聚合时间变化的关系,考察其聚合反应动力学.改变引发剂过氧化苯甲酰(BPO)含量发现,BPO质量百分数提高聚合反应速率加快,单体转化率差别不大;提高温度有利于聚合速率的提高,但同时会导致单体最终转化率的降低;单体浓度越高,聚合速率越快,凝胶化现象明显;采用乙苯为溶剂...     

环糊精和乳化剂共存下苯乙烯的乳液聚合动力学

以过硫酸钾为引发剂,十二烷基硫酸钠为乳化剂,在β-环糊精(β-CD)存在下进行乳液聚合动力学研究,考察了引发剂浓度、乳化剂浓度、β-环糊精浓度以及聚合温度对聚合反应速率的影响,测定了各项反应级数和聚合表观活化能。结果表明,聚合反应速率随引发剂浓度、乳化剂浓度和聚合温度的升高而加快,随β-环糊精浓度的升高先增加后降低,在β-CD浓度≤1.555×10-3 mol/L时,聚合反应动力学关系式为Rp∝[KPS]0.5277[SDS]0.5631[β-CD]0.9987,表观活化能为72.55 kJ/mol。     

光化法合成液体端羟基聚丁二烯

研究了丁二烯/过氧化氢/乙醇体系的光化聚合反应。首次采用有机光敏剂作为助引发剂,提高了聚合速率。同时考察了单体浓度、引发剂浓度和反应时间对单体转化率及反应速率的影响。产物为液态物质,其羟基官能度为2.0～2.4。表征结果说明聚合产物为端羟基液体聚丁二烯。     

聚酰胺胺树状大分子作为种子的乳液聚合动力学及乳胶粒径

以聚酰胺胺(PAMAM)树状大分子作为种子,过硫酸铵(APS)为引发剂,十二烷基苯磺酸钠(DBS)为乳化剂,进行了苯丙乳液聚合动力学研究。考察了3.0GPAMAM树状大分子浓度、引发剂浓度、乳化剂浓度和反应温度对聚合动力学的影响,并研究了PAMAM树状大分子代数对乳胶粒子粒径的影响。实验结果表明,聚合反应速率随3.0GPAMAM树状大分子浓度的升高先增加后降低,随反应温度、引发剂浓度和乳化剂浓度升高而加快;在3.0GPAMAM树状大分子浓度小于2.392×10~(-4)mol/L时,聚合反应动力学关系式为Rp∝[3.0GPAMAM]~(0.87)[DBS]~(0.507)[APS]~(0.256),表观活化能为66.91k J/mol;随着PAMAM树状大分子代数的增加,乳胶粒子的粒径逐渐减小,并呈现单分散性。     

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