层层自组装PDADMAC/PSS纳滤膜的制备

以荷负电的聚砜超滤膜为基膜,采用静态层层自组装技术,制备了PDADMAC/PSS多层聚电解质纳滤膜.考察了支撑盐的种类、浓度、自组装层数对膜的分离性能、荷电性能、亲水性等的影响.研究结果表明,以NaCl为支撑电解质制得的膜具有较高的性能,聚合电解质溶液中支撑电解质的浓度以0.5mol/L为宜;在较优的条件下所制备的(PDADMAC/PSS)5对2g/L Na2SO4的截留率可达93%,通量在1.0MPa下接近60L/(m2.h),对NaCl的截留率仅为9%～13%,通量可达80L/(m2.h).膜表面的荷电量和接触角的变化均反映了聚电解质的交替自组装.以PSS为最外层的膜表面具有很好的负电性和很低的接触角.随着双层数的增加,膜表面的负电荷量的绝对值先逐渐增大,达到一个极大值后又逐渐减少,说明层数并非越多越好;以PSS作为最外层的膜具有很好的亲水性.     

高强度、亲水性聚醚砜中空纤维超滤膜的制备技术

膜生物反应器(MBR)是目前水处理领域中的热点之一,但是中空纤维膜的强度低、亲水性差的缺点限制了它的广泛应用。首先设计并制造了集束型喷丝头,然后以聚醚砜为膜材料,利用干/湿法纺制了截留分子量分别为10KD和20KD,水通量为15～100 L/(m2.h.0.1MPa),爆破压力为0.5～1.0MPa,拉伸强度可达10MPa以上的高强度聚醚砜中空纤维膜;再利用有机/无机共混改性,通过引入金属离子和可溶性聚合物的络合反应形成的络合物,制得了截留分子量分别为6KD、10KD、20KD、50KD、100KD、水通量达到25～400 L/(m2.h.0.1MPa)的一系列强度高、亲水性好的聚醚砜中空纤维超滤膜。     

壳聚糖-聚乙烯醇共混物/聚丙烯腈复合纳滤膜的研究

以壳聚糖和聚乙烯醇共混物溶液为铸膜液,涂敷在聚丙烯腈超滤膜上,以戊二醛为交联剂,制备了荷正电壳聚糖-聚乙烯醇共混物/聚丙烯腈复合纳滤膜.探讨了交联时间、交联温度、交联剂浓度、铸膜液浓度等因素的影响,采用单因素实验确定了最佳制膜条件为:以1.5%(质量分数)的壳聚糖和聚乙烯醇共混液为铸膜液,50℃下干燥2h,在戊二醛与无水乙醇质量比为0.75∶50的体系中交联,在40℃水浴中交联4h,50℃下热处理15min.在温度为25℃,流速为30L/h,操作压力为1.0MPa时,对复合膜的性能进行了测试,分别探讨了操作压力和料液类型等因素与膜性能的关系.其纯水渗透系数为5.80L/(h·m2·MPa).对1000mg/L NaCl、MgCl2、MgSO4和Na2SO4的截留率分别为63.50%、94.30%、81.00%、32.70%,通量分别为3.10、3.65、2.40、2.70L/(h·m2).对不同类型无机盐的截留顺序为MgCl2＞MgSO4＞NaCl＞Na2SO4,呈现阳离子型复合纳滤膜的截留特征.流动电位曲线进一步说明了该复合膜荷正电性,其电压渗系数β为5.68mV/Pa.通过扫描电镜对膜的结构进行了表征,显示了该膜的复合结构.     

NaA分子筛改性聚砜超滤膜的通量及截留性能

利用溶液相转化法,在铸膜液中加入分子筛NaA和PEG来协同提高聚砜超滤膜的水通量和截留率,研究了分子筛的含量对聚砜超滤膜的形貌结构,表面粗糙度,水通量,蛋白质截留率和亲水性的影响。利用场发射扫描电镜、扫描探针原子力显微镜、膜评价仪和接触角仪分别对该膜的形貌、水通量、蛋白质截留率和亲水性进行表征。结果表明分子筛含量从0g增加到3.0g,聚砜超滤膜的水通量从140L/(m2·h)提高到500L/(m2·h),对胃蛋白酶的截留率从78.8%提高到92.7%,对牛血清蛋白的截留率从97.6%增加到99.0%以上。分子筛NaA可以协同提高聚砜超滤膜的水通量和蛋白质截留率。     

磺化聚砜/聚醚砜共混非对称纳滤膜的制备与性能表征

以相转化法制备了磺化聚砜(SPSF)/聚醚砜(PES)共混新型纳滤膜,并研究了磺化聚砜的磺化度以及聚醚砜/磺化聚砜的共混质量比对低分子量PEG的截留率和脱盐率性能的影响.结果表明:在操作压力为0.5MPa,料液温度为25℃下,当PES/磺化度10%SPSF共混比为6∶4时,SPSF/PES共混膜对PEG1000、PEG800和PEG600的截留率分别为99.8%、81.0%和57.8%,对硫酸钠、氯化钠的截留率分别为69.0%和23.5%,SPSF/PES共混膜的纯水通量为90.3L/(m2.h).     

共价层层自组装纳滤膜的制备及性能研究

纳滤膜目前多采用界面聚合的方法制备.层层自组装是近年来发展的一种新型制膜方法,但层层自组装所制备的纳滤膜大多需要5个以上双层,制备过程繁琐,同时,以静电力结合的阴阳离子聚电解质在水中存在一定程度的解离和溶胀,结构不稳定.本文提出用静电组装与化学交联相结合的方法制备纳滤膜,增强膜的稳定性.以改性的聚丙烯腈(PAN)为基膜,以聚丙烯酸(PAA)和聚乙烯亚胺(PEI)分别为阴阳离子聚电解质,以戊二醛(GA)为交联剂,制备了共价层层自组装纳滤膜(PEI/PAA/GA)n,研究了双层数、交联剂浓度、交联时间等因素对膜性能的影响.结果表明,当制备两个双层时,(PEI/PAA/GA)_2纳滤膜对2 000 mg/L Na_2SO_4溶液中的Na_2SO_4的截留率就能达到98.1%,水通量为12.6 L/(m~2·h·MPa);对2 000 mg/L NaCl溶液中的NaCl的截留率达到82.9%,水通量为16.8 L/(m~2·h·MPa).交联后的纳滤膜有良好的耐溶胀性和长期运行稳定性.     

聚丙烯酸钠复合超滤膜研制初探(Ⅰ) UPANA-1复合膜的制备

以聚丙烯酸钠为复合膜分离层材料,多孔的聚醚砜(PES)超滤膜为基膜研制出具有超薄分离层的聚丙烯酸钠复合超滤膜(UPANA-1).用浓度为0.005 g/L的分子量为1 000的聚乙二醇水溶液作为介质溶液,室温、压力0.6 MPa下做膜性能测试,UPANA-1膜的截留率大于90%,水通量为32.6 L/(m2*h).并着重研究了基膜的选择、超薄分离层膜液的组成等制膜条件对复合膜性能的影响.     

聚丙烯酸钠复合超滤膜研制初探（I）UPANA—l复合膜的制备

以聚丙烯酸钠为复合膜分离层材料,多孔的聚醚砜(PES)超滤膜为基膜研制出具有超薄分离层的聚丙烯酸钠复合超滤膜(UPANA-1).用浓度为0.005 g/L的分子量为1 000的聚乙二醇水溶液作为介质溶液,室温、压力0.6 MPa下做膜性能测试,UPANA-1膜的截留率大于90%,水通量为32.6 L/(m2*h).并着重研究了基膜的选择、超薄分离层膜液的组成等制膜条件对复合膜性能的影响.     

SiO2/PSf杂化超滤膜制备和性能研究

分别以粉末和溶胶-凝胶的方式向聚砜铸膜液中添加不同含量的SiO2,通过L-S相转换法制备SiO2/PSf杂化超滤膜.比较两种体系在不同SiO2含量下铸膜液的稳定性、黏度,及膜的微观结构、平均孔径、孔隙率、渗透性能和机械性能.结果表明,以溶胶-凝胶方式添加SiO2的铸膜液更加稳定,各方面性能更好.粉末添加下SiO2含量为2%时效果较好,水接触角为62°,纯水通量为141 L/(m2·h),对腐殖酸(Mr=370 000)的截留率为83.7%;溶胶-凝胶添加下SiO2含量为8%～10%时效果较好,水接触角为40°,纯水通量为182 L/(m2·h),对腐殖酸(Mr=370 000)的截留率为92%.     

聚酰胺／聚砜纳滤中空纤维复合膜的截留性能

以哌嗪水溶液为水相,均苯三甲酰氯正己烷溶液为有机相,通过在聚砜中空纤维基膜上进行界面聚合,制备出聚哌嗪均苯三甲酰胺/聚砜纳滤中空纤维复合膜,并考察其对电解质和非电解质,特别是对维生素C、柠檬酸、维生素B2、秋水仙碱、维生素B12等单组分水溶药物的截留行为.结果表明,对MgSO4、Na2SO4的截留率达到98%,对MgCl2的截留率大于70%;对一价盐NaCl的截留率小于40%;对于分子量小于200的甘露糖截留率为78%;对分子量相近的维生素C、柠檬酸的截留率更低,不到50%;而对于分子量大于300的蔗糖、棉子糖、维生素B2、秋水仙碱、维生素B12的截留率大于92%,并且具有相当的膜通量.因此,聚酰胺/聚砜纳滤中空纤维复合膜的截留分子量为200～300.     

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...     

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.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.