聚乙烯醇/钴盐共混膜结构及其对环己烯-环己烷吸附性能研究

采用PVA分别与硝酸钴(Co(NO3)2)、氯化钴(CoCl2)和醋酸钴(Co(CH3COO)2)共混制成均相膜．X-射线衍射研究表明：Co(NO3)2,CoCl2和Co(CH3COO)2能很好地溶于PVA中,且PVA膜中引入钴盐后,结晶度明显下降．通过对环己烯、环己烷溶胀实验发现,3种膜均对环己烯优先吸附,其中PVA／Co(CH3COO)2膜对环己烯优先吸附性能最好,而且环己烯在膜中的扩散也最快达到平衡．     

PVA/PVP/Ag+共混膜渗透汽化分离苯/环己烷混合物

PV/PVP/Ag+膜在苯、环己烷混合物中的溶胀实验发现,膜优先吸附苯,且膜中Ag+含量越大,膜在苯中的溶胀率越大,在环己烷中溶胀率越小.渗透汽化测试结果也表明,PVA/PVP/Ag+膜对苯/环己烷的分离性能明显优于PVA/PVP膜.而且,随着膜中Ag+含量的增加,膜的渗透通量J增大;分离因子先增大后减小,当膜中w(聚合物)∶w(AgNO3)＝1∶1时,分离因子α达到最大值,为47.5,通量为7.8 g/(m2*h)(进料的质量分数为10%,20 ℃).而对膜进行交联改性后,分离因子可进一步提高,但通量下降.     

MWCNT/poly(MMA-AM)杂化膜的原位聚合制备及其苯与环己烷的吸附-溶胀性能

多壁碳纳米管(MWCNT)经HNO3/H2SO4混酸氧化处理、二氨基-二苯甲烷化学修饰后,得到胺功能化多壁碳纳米管(MWCNT—NH2);通过原位聚合制备多壁碳纳米管/甲基丙烯酸甲酯-丙烯酰胺共聚物杂化膜。采用拉曼光谱、红外光谱、扫描电镜表征了多壁碳纳米管化学修饰前、后的结构和形貌;采用扫描电镜和zeta电位仪分析了杂化膜的结构和表面荷电特性;实验考察了杂化膜在苯、环已烷中吸附-溶胀性能。研究结果显示,MWCNT—NH2/poly(MMA-AM)杂化膜的表面zeta电位随MWCNT—NH2填充量的增加而增大,MWCNT—NH2在杂化膜中分散性较好;在碳纳米管填充量相同的情况下,MWCNT—NH2/poly(MMA-AM)杂化膜的苯平衡吸附-溶胀度与苯/环己烷吸附-溶胀选择性大于MWCNT/poly(MMA-AM)杂化膜。MWCNT—NH2/poly(MMA-AM)杂化膜的苯平衡吸附-溶胀度与苯/环己烷平衡吸附-溶胀选择性随MWCNT—NH2填充量的增加而增大;而MWCNT/poly(MMA-AM)杂化膜的苯平衡吸附-溶胀度随MWCNT填充量的增加略有增大,苯/环己烷平衡吸附-溶胀选择性随MWCNT填充量的增加呈下降趋势。研究结果表明,MWCNT—NH2/poly(MMA-AM)杂化膜对苯/环己烷具有苯优先选择吸附-溶胀的特性,且苯优先选择吸附-溶胀的特性随杂化膜中MWCNT—NH2填充量的增加而更加显著。     

渗透汽化分离有机物

用不同的方法制备了几种分离有机物的膜，如CA/PAN、PVA/PAN的复合膜，以及含金属离子载体的PVA膜，这些膜是复合膜或非对称膜．测量了膜材料(CA和PVA—Me^n )的吸附特性并评价了其性能．结果表明，CA和CTA膜以及几种复合膜适于分离MTBE/MeOH，修正的溶解-扩散模型可成功地估算MTBE／MeOH透过CA膜的渗透汽化分离性能．从初步吸附试验看，含金属离子载体的PVA膜对分离苯／环乙烷体系可能是一好的候选膜．     

新型螯合纤维在金属离子富集分离中的应用

近年来,螯合纤维在金属离子的提取、分离、分析等方面的研究成为分离科学领域的研究热点。螯合纤维对金属离子具有很强的吸附性和高的选择性,可以用于放射性金属、贵金属、过渡金属和稀土金属离子的回收、富集和分离等方面。为了进一步提高螯合纤维的吸附性和选择性,众多学者对如何制备出性能优良的螯合纤维进行了大量的研究工作。综述了近年来新型螯合纤维的制备和吸附性能。     

钌基催化剂催化苯部分加氢制环己烯的研究进展

环己烯具有活泼的双键,被广泛用于医药、农药、食品及其他高附加值精细化学品的生产中。工业上生产环己烯的方法主要有环己烷脱氢、环己醇脱水、卤代环己烷脱卤化氢、Birch还原和苯部分加氢等。相比于其他方法,苯部分加氢制环己烯工艺由于具有安全可靠、原子经济性强、环境友好等优点,引起了研究者的广泛关注。从热力学角度看,苯加氢生成环己烯的标准Gibbs自由能比生成环己烷的标准Gibbs自由能低75 k J/mol,极不利于环己烯的生成。另外,苯环共轭大π键的化学性质较环己烯双键更稳定,在催化剂存在下环己烯极易深度加氢生成环己烷,反应难以停留在环己烯阶段。除引入水相外,催化剂是实现苯部分加氢制备环己烯工艺过程的关键,因此开发高活性、高选择性的催化剂显得格外重要。100多年前人们就开始探索苯部分加氢制环己烯工艺。自1957年Anderson在Ni膜催化苯加氢产物中检测到环己烯的存在以来,一些研究者陆续报道了钌催化剂催化的苯加氢反应,在苯转化率较低的情况下能检测到中间产物环己烯,并发现钌催化剂最适合该反应。其中,一项极为重要的研究进展是在含油相、水相、气相和固相的四相反应体系中,以过渡金属盐为添加剂,在剧烈搅拌下反应,环己烯收率可高达60%,提高了技术可行性。1989年日本旭化成公司率先实现了Ru-Zn催化苯部分加氢制环己烯工艺的工业化。1995年,我国神马集团引进日本旭化成苯部分加氢技术。随着技术的引进,国内各大科研院所、高校等的多个课题组相继加入苯选择加氢制环己烯催化剂的研究,研究工作主要集中在优化和完善催化反应条件、研制新催化剂、探索提高环己烯选择性的本质原因。近年来,大量文献报道通过合理设计Ru催化剂来提高环己烯选择性,如采用Na OH溶液对Ru/ZrO_2催化剂进行锌刻蚀以增加催化剂表面羟基量,提高催化剂亲水性;又如通过添加合适的助剂La、Cu、Fe、Mn等对催化剂进行改性,从而提高反应选择性。虽然报道的催化剂体系很多,但目前国内工业化生产使用的均是传统Ru-Zn催化剂,且日本旭化成公司一直控制着催化剂的核心制备技术。本文介绍了苯部分加氢反应的反应机理、热力学特征及传质现象,着重概述了近年来苯部分加氢钌基催化剂的研究现状,包括催化剂前驱体、催化剂制备方法、载体、助剂以及添加剂对催化剂性能的影响,对现阶段研究存在的问题进行了总结,并展望了今后的发展前景。     

静电纺制备耐水抗菌性姜黄素纳米纤维膜及其性能研究

姜黄素(Cur)在医药上有着很广泛的应用，可用于抗癌、抗菌、抗病毒、抗炎等。制备了一种聚乙烯醇/聚丙烯酸(PVA/PAA)载姜黄素纳米纤维材料，可用于伤口敷料，能有效抗菌，可促进伤口愈合。首先采用二甲亚砜将姜黄素溶解，再将含有姜黄素的溶液与PVA/PAA水溶液共混，利用静电纺丝技术制备出纳米纤维膜后对其进行高温热交联处理使其提高耐水性。对纳米纤维膜的表面形貌、化学结构、抗菌性能、溶胀性能以及透湿性能进行表征与分析。结果表明：PVA/PAA载姜黄素纳米纤维膜具有一定的抗菌效果，并且透湿性以及吸液性能良好。     

Ag~+固载传递膜的制备及其分离烃类混合物的研究

利用聚乙烯醇(PVA)水解物制备了固载Ag~+促进传递膜。采用扫描电镜对膜的形貌进行了表征,探究了单一因素SiO_2投加量、不同阴离子及光还原时间对膜分离性能的影响。结果表明,纳米SiO_2的加入改变了膜的分离性能;固载双三氟璜酰亚胺银(Ag[Tf_2N])相比AgNO_3具有更好的气体渗透性能和分离性能;随着光还原时间的进行,渗透速率和分离因子均有所下降。     

聚乙烯醇/[Nbmd]OH碱性复合阴离子膜的制备及性能

以吗啡啉与溴代十二烷为原料,合成新型[Nbmd]OH碱性双核离子液体,并将[Nbmd]OH引入聚乙烯醇(PVA)的铸膜液中,通过浇铸法制备了掺杂碱性离子液体的复合阴离子膜PVA/[Nbmd]OH。采用热重分析及扫描电镜对所制备的复合阴离子膜的热稳定性及形貌进行表征。同时考察了离子液体含量对PVA/[Nbmd]OH复合膜的含水率、溶胀性能、力学性能及电导率的影响。结果表明,离子液体含量的增加可提高PVA/[Nbmd]OH复合膜的含水率、溶胀度、电导率等。其中,当碱性离子液体质量分数为20%时,复合膜的综合性能达到最优,此时,膜的含水率和拉伸强度分别达到161.6%和23 MPa,在70℃时,膜的电导率为2.11×10~(-3)S/cm,表明碱性离子液体的引入,能明显改善膜的导电性能,但是拉伸强度受到了一定的影响。     

2004年《膜科学与技术》总目次

(括号内数字依次为卷数、期数、页数 )研究报告膜 -生物反应器处理高浓度有机废水膜污染影响因素的研究王　颖　黄　霞　袁其朋 (2 4 ,1,0 1)………………………丝素 -壳聚糖共混膜的制备及其金属离子渗透行为的研究杜春慧　朱宝库　陈建勇 ,等 (2 4 ,1,0 6 )…………………………聚砜中空纤维膜在丙烯酰胺微生物转化中的应用基础研究孙旭东　史　悦　沈忠耀 (2 4 ,1,11)…………………………U型中空纤维膜水力特性的模型分析杨大春 (2 4 ,1,16 )………………………………………………………………………烃类在固载金属离子PVA膜中的溶胀…     

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.     

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...     

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.     

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.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.