均相体系中改性纤维素的制备及其对亚甲基蓝的吸附性能研究

为了开发低成本、环境友好的吸附材料用于吸附、分离水中的染料离子,在均相体系中,以纤维素为基材、过硫酸钾为引发剂、甲基丙烯酸缩水甘油酯(GMA)为接枝单体,制备了纤维素接枝共聚物Cell-g-PGMA,并通过FT-IR、XRD和TGA对接枝共聚物进行了表征。系统研究了接枝时间、温度、单体用量和引发剂用量对接枝率的影响。同时在不同吸附时间、温度、吸附剂用量和初始浓度下考察了Cell-g-PGMA对亚甲基蓝(MB)离子的吸附性能。研究表明,该吸附剂对MB表现出优异的吸附性能,理论最大吸附量为271.39mg/g,吸附过程符合准二级动力学模型和Langmuir吸附等温线。     

SCB-g-MMA的固相接枝制备及其吸附性能

采用固相接枝法将甲基丙烯酸甲酯(MMA)接枝到碱处理后的甘蔗渣(SCB)表面,得到固相接枝产物甲基丙烯酸甲酯接枝甘蔗渣(SCB-g-MMA),并通过XRD、FTIR、13 C NMR、SEM和BET(Brunauer-Emmett-Teller)测试等方法对其结构进行表征分析。将SCB-g-MMA作为亚甲基蓝(MB)的吸附剂,进行吸附性能研究。结果表明:在室温下,MB初始浓度在50~400mg/L范围内,当吸附剂投加量大于等于10g/L时,溶液pH范围在6~12,吸附时间超过40min,SCB-g-MMA对MB的去除率达到99%;当吸附剂投加量为2.5g/L时,对MB的吸附量可达97.3mg/g。SCB-g-MMA对MB吸附动力学和吸附等温线更符合准二级动力学方程和Freundlich等温吸附模型。     

层状双金属氧化物吸附溶液中硼的性能研究

采用共沉淀法合成层状双金属氢氧化物并经过高温煅烧后形成层状双金属氧化物,用扫描电子显微镜对样品进行了表征。研究了层状双金属氧化物对硼的吸附性能,考察了溶液pH值、吸附剂用量、吸附时间、吸附温度对吸附性能的影响。实验结果表明,层状双金属氧化物对模拟废液中的硼有很好的吸附效果,当溶液pH值=9.5、吸附剂用量为0.20g、硼初始浓度为100mg/L、反应时间为100min、温度为303K时对硼的去除率为94.47%,吸附量为47.24mg/g。等温吸附研究结果表明,Langmuir模型能更好地描述吸附过程,表明Mg/AlLDO对硼的吸附主要发生在Mg/Al-LDO表面的活性区域,属于饱和单分子层吸附。     

开链氮杂冠醚化球形竹纤维素的制备及其吸附性能

以竹粉为原料,采用化学方法制备得到球形纤维素,扫描电镜观察球形纤维素粒径均匀,直径约为600μm。通过三因素三水平正交实验研究NaOH溶液添加量、分散相用量和分散剂用量对球形竹纤维素粒径的影响。最佳实验条件为:NaOH溶液添加量为16mL/g、分散相用量为15g和分散剂用量为13%。通过环氧氯丙烷和开链氮杂冠醚化制备得到改性的开链氮杂冠醚化球形竹纤维素。研究了反应温度对接枝改性的影响,反应温度为50℃时,接枝率达到最大值为76.6%。最后研究了改性球形竹纤维素对Cu2+的静态和动态吸附性能,其静力学吸附的饱和吸附容量为97.93mg/g,动力学吸附的有效吸附时间为40min。     

AA/SiO2/CTS复合材料制备及其吸附铬离子研究

通过浸渍法分别用丙烯酸(AA)和纳米二氧化硅(SiO₂)改性壳聚糖(CTS),制备AA/SiO₂/CTS复合材料。通过红外光谱表征了复合材料的结构，并以复合材料为吸附剂吸附铬离子，研究了复合材料吸附铬离子的吸附性能。结果表明：当吸附剂用量为2.0g, pH为6左右，铬离子浓度为20mg/L,温度为25℃,吸附70min时，吸附效果最好，改性后的复合吸附剂AA/SiO₂/CTS的吸附率最高可达96%,明显高于未改性CTS的85%和AA/CTS的92%。吸附热力学和动力学研究表明，Freundlich等温模型和拟二级动力学模型更加符合吸附过程。     

累托石-壳聚糖复合材料的制备及对Ni~(2+)的吸附

将累托石与壳聚糖混合制得一种复合吸附剂.研究了累托石-壳聚糖吸附剂制备的条件和利用该复合吸附剂对含镍水溶液进行吸附.研究结果表明:当壳聚糖与累托石的比为0.06,壳聚糖脱乙酰度为90%时,制成的吸附剂吸附效率高.在pH值6～8,吸附时间为30min,吸附剂用量为5.0g/L时,Ni2+的吸附率迭99%以上,处理后的水符合国家污水综合排放标准(GB8978-1996)中的一级标准.此外还对该复合吸附剂结构进行了表征.     

凹凸棒石黏土-腐植酸复合吸附剂吸附Cr(Ⅵ)的性能研究

为促进凹凸棒石黏土-腐植酸复合吸附剂在水处理中的应用,用酸改性的甘肃靖远凹凸棒石黏土和天祝褐煤提取的腐植酸制备出凹凸棒石黏土-腐植酸复合吸附剂,通过SEM、XRD、FT-IR等分析方法对复合吸附剂的结构进行了表征,考察了物料配比及吸附时间、pH值、温度、投加量和初始浓度对Cr(Ⅵ)吸附率的影响。结果表明:靖远凹凸棒石黏土最佳酸改性条件为盐酸5 mol/L,酸化时间120 min,酸用量固液比为1∶10。当Cr(Ⅵ)的起始浓度为0.1 g/L,体积为50 m L,复合吸附剂用量为1.2 g,吸附时间为6 h,p H值为6,温度25℃,酸改性的凹凸棒石黏土与腐植酸的最佳复合比为1∶3时,复合吸附剂对Cr(Ⅵ)的吸附率达到91.7%。复合吸附剂对Cr(Ⅵ)的吸附满足Freundlich模型。在25~45℃条件下,吸附过程ΔG <0、ΔS=87.46 J/(mol·K)、ΔH=-21.2 kJ/mol,表明该吸附是一个自发、熵增、放热的过程。     

马来酸酐改性纤维素吸附剂的制备及性能

以1-烯丙基-3-甲基氯代咪唑[AMIM]Cl离子液体为介质,用4-二甲基氨基吡啶(DMAP)作催化剂,合成了马来酸酐改性纤维素吸附剂,探索了较优合成条件:催化剂DMAP用量为3%(wt,质量分数),马来酸酐与纤维素质量配合比为5∶1,100℃的条件下反应4h,此时合成物的取代度为0.10。采用FT-IR红外检测、热重分析、扫描电镜和原子吸收分光光度测试对合成物吸附剂进行了表征,并进行了吸附效果实验,结果表明合成物吸附剂对二价金属离子有较好的吸附效果,对Cu~(2+)和Mn~(2+)的最大吸附量能达到168mg/g和149mg/g。     

果胶磁性微球的制备及其对Mn(Ⅱ)及Cr(Ⅵ)的吸附性能

以氯化钙为交联剂,采用包埋法制备了一种果胶磁性微球吸附剂,通过红外光谱、扫描电镜、XRD、磁性分析和TGA对样品进行了表征,并考察了吸附时间、Mn2+(Cr6+)的浓度、吸附剂用量和吸附溶液的pH对果胶磁性微球吸附性能的影响。分析了果胶磁性微球分别吸附Mn(Ⅱ)和Cr(Ⅵ)的吸附动力学、吸附等温线。结果表明:果胶磁性微球对Mn(Ⅱ)和Cr(Ⅵ)的吸附达平衡分别需要4h和1.5h,饱合吸附量分别为54.35mg/g和9.62mg/g,吸附等温线较好地满足Freundlich模型和Langmuir模型,最大吸附量分别为102.04mg/g和25.45mg/g。吸附动力学符合准二级动力学模型,主要由化学吸附控制其吸附速率。     

改性亚麻屑纤维素对活性翠蓝染料的吸附性能研究

采用环氧氯丙烷和三乙胺对分离出来的亚麻屑纤维素进行改性,制备了一种新型吸附剂。采用扫描电子显微镜和傅里叶变换红外光谱仪分别观察了所制备的吸附剂的表面形貌并分析了主要官能团,研究了其对活性翠蓝染料的吸附性能,探讨了吸附时间、吸附剂用量、染料初始浓度及pH等对吸附的影响。结果表明,随时间延长吸附容量逐渐增加,180 min后吸附即可达到平衡,升高温度有利于吸附反应的进行,40℃时最大吸附容量为198.45 mg/g;染料初始浓度较高时,吸附容量较大,吸附受pH的影响较为明显。     

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.……     

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.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

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.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.