直接水热合成法和模板剂法制备碳微球的比较及性能评价

以葡萄糖为碳源,分别采用直接水热合成法和模板剂法制备了碳微球并将其制备成催化剂。利用扫描电镜和傅里叶变换红外光谱仪等手段对碳微球及催化剂进行表征。评价了催化剂在纤维素水解反应中的催化活性。结果表明:两种方法制备的碳微球粒径相差较大,结构上都含有—OH和—COOH官能团;两种方法制备的催化剂粒径有很大差别而且球之间粘连较严重,两者均含有—SO3H、—COOH、—OH等活性基团。并且模板剂法制备的碳微球催化剂对纤维素的水解率较高,达到58%。     

核孔膜乳化法制备单分散壳聚糖微球

选择壳聚糖溶液为分散相,液体石蜡为连续相,首次采用核孔膜乳化方法制备壳聚糖微球.乳滴经戊二醛交联固化后所得微球球形度和单分散性良好(分散系数＜20%).主要研究了核孔膜孔径大小、油水相体积比、表面活性剂种类及用量、温度和固化时间对微球制备的影响.结果表明,膜乳化法是制备单分散微球的良好方法.     

纤维素/木质素微球抗紫外薄膜制备与性能研究

随着包装工业的快速发展和人类社会对环保要求的提高,功能性且可生物降解的包装膜材料越来越受到人们的重视.然而,目前市场上的可降解包装膜材料由于成本较高、力学性能差以及耐水性低而限制了其发展.采用自组装方法制备木质素微球,并将其沉积在纤维素膜表面,制备出一种新型纤维素基抗紫外薄膜材料.通过扫描电子显微镜(SEM)、红外光谱(FTIR)和激光共聚焦电子显微镜对薄膜的表面性能进行研究.利用抗张实验和紫外透光率测试对纤维素基功能薄膜的力学性能和抗紫外性能进行表征.结果表明:自沉积木质素微球在纤维素膜表面分布均匀,尺寸为1～2μm;纤维素薄膜疏水改性后有助于木质素微球的沉积,且沉积量随着木质素质量浓度的增加而增大.由于木质素微球的引入,纤维素复合膜的抗张强度比对照样增加22％,同时其对UVB屏蔽效果可达94％.     

改性海藻酸钠聚合物微球制备及药物释放研究

为了制备功能化的栓塞微球,提高微球的载药率,以海藻酸钠(SA)为起始原料,经牛磺酸(TA)改性,采用反相乳液聚合方法将改性后的产物制得栓塞微球。用扫描电子显微镜(SEM)、超景深显微镜、紫外/可见分光光度计等对微球进行了鉴定和表征,并测定了改性前后SA水溶液的黏度。结果表明:改性后的SA溶液在水中的黏度有所降低;微球直径100~500μm;与未改性聚合物相比,改性后的SA微球负载药物阿霉素最高达到30%;载药微球对药物阿霉素的累计释放量增加,缓释现象明显。     

原位聚合制备PLLA/Fe3O4磁性复合微球及其表征

介绍了一种新的PLLA/Fe3O4磁性复合微球的制备方法——表面引发开环聚合法,先利用硅烷偶联剂Z-6040对Fe3O4进行改性,在其表面引入羟基,再通过羟基引发丙交酯在磁粒子表面开环聚合制备PLLA/Fe3O4磁性复合微球。探讨了复合微球的形成机理,对磁粒子改性效果和微球形貌、粒径、结构、磁含量及磁性能等进行了表征,并详细研究了磁性复合微球性能的影响因素。     

TiO2纳米管包覆聚乙烯醇凝胶微球的制备及性能研究

通过水热法制备了二氧化钛纳米管(TNT),并使用油酸对其表面进行改性。以改性TNT为稳定剂,W/O型Pickering乳液为模板,通过冻融法制备了聚乙烯醇/二氧化钛纳米管(PVA/TNT)复合微球。采用高分辨透射电子显微镜、扫描电子显微镜、X射线能谱仪、热重分析仪等对改性TNT和PVA/TNT复合微球的结构及形貌进行了表征,选择亚甲蓝溶液作为模拟废水,对PVA/TNT复合微球光催化降解性能进行了研究。结果表明:改性TNT能很好地稳定W/O型Pickering乳液,以该乳液为模板可以制备出壳层包覆TNT、内核为聚乙烯醇凝胶的复合微球。PVA/TNT复合微球微球对亚甲蓝具有良好的吸附及光催化降解性能。     

复合CaCO3法制备医用多孔明胶微球

采用W/O型乳化-固化法制备了明胶CaCO3复合微球,将此复合微球用盐酸处理除去表面CaCO3,得到多孔的明胶微球.以差示扫描量热法、热重分析、红外光谱、扫描电子显微镜等方法对复合微球和多孔明胶微球的物理性质进行了表征,同时探讨了多孔明胶微球的合成机理.结果表明,两种微球中均含有CaCO3;扫描电镜显示,微球表面呈多孔结构,粒径在20～40μm之间.     

注凝工艺制备二氧化锆陶瓷微球

采用注凝工艺制备二氧化锆陶瓷微球，测试了微球的性能，研究了分散剂、引发剂以及真空除泡等对浆料性质的影响。结果表明：将催化剂加入至二甲基硅油中可以避免浆料提前固化，有效延长其稳定存放时间，同时还可将浆料固化所需温度从90℃降低到50℃。采用振动分散技术可以获得尺寸分布均匀的二氧化锆陶瓷微球。     

喷雾干燥结合紫外交联制备甲基丙烯酸缩水甘油酯改性丝胶中空微球及其性能

为了制备高耐水性光固化丝胶蛋白(SS)微球,采用喷雾干燥与紫外交联相结合的方法,以丝胶为原料制备了甲基丙烯酸缩水甘油酯(GMA)交联SS中空微球(GMA-g-SS),该法赋予了其良好的耐水稳定性和紫外光固化性能。优化的喷雾干燥工艺参数包括：SS浓度、进风温度及进液速度;研究了GMA浓度、二苯甲酮(BP)用量及紫外辐照时间对接枝率的影响。借助扫描电镜、红外光谱及热分析对微球表面形貌结构及稳定性进行了表征与分析。结果表明,喷雾干燥SS微球呈单分散空心结构,直径约5～20μm;GMA-g-SS微球红外光谱在1152 cm^-1和764 cm^-1处出现环氧基的吸收峰,表明GMA与SS交联成功。交联后微球呈黏连聚集状态,具有较高的紫外光固化性能且耐水稳定性大幅提升,溶失率仅为17.1%。所制备的GMA-g-SS微球具有可调的耐水稳定性和紫外光固化性,是一种有潜力的光固化3D打印生物材料。     

以花粉为范铸造微球及其载酶活性测试

介绍了利用天然花粉作为模具,通过微铸造的方式制备微球的一种新方法。微球制备过程中,选用葵花、山茶花及玫瑰花3种粒径及形状不同的花粉作为模具。使用时先去除花粉内部细胞后形成中空结构作为模具,再注入海藻酸钠溶液后,经CaCl_2溶液浸泡固化成型,最后在果胶酶和纤维酶联合作用下去除花粉壁即可以得到形状规则,粒径均一的3种海藻酸钠微球。该方法制备微球简便易行、条件温和、对设备要求低且适用范围较广。此外,对该方法所制备负有载碱性蛋白酶的微球进行活性测试结果还显示出保留花粉壁结构可以使微球活性更有优势。     

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.