柠檬酸溶胶燃烧工艺参数对Ca_3(VO_4)_2:Eu~(3+)发光性能的影响

采用柠檬酸溶胶燃烧法合成了Ca3(VO4)2:Eu3+红色发光材料。利用XRD、SEM、荧光分光光度计等测试分析方法研究了合成温度、柠檬酸用量以及Eu3+含量等对合成样品组成、结构、显微特征和发光性能的影响。结果表明,采用柠檬酸溶胶燃烧法可以在700～1000℃范围内合成纯度高、结晶度好、粒度均匀的Ca3(VO4)2:Eu3+红色发光粉。优化条件为温度900℃、n(柠檬酸):n(Ca2++V5+)=0.8、Eu3+摩尔分数6%,合成产物的红光发光效果最好。     

天然植物纤维型鲜肉保鲜包装膜的研究

采用NMMO-纤维素法制备保鲜包装膜,通过改变纤维素浓度、凝固浴温度与浓度、抗菌剂种类及浓度等影响因素,最终得出较佳制备工艺;对薄膜进行性能测试,结果表明:纤维素浓度为5%,凝固浴温度为45℃,凝固浴浓度为0%的条件下制成的膜性能较好。对膜进行保鲜处理,并对其保鲜效果进行检测。实验结果为:2.5%的无机抗菌膜、2%的有机抗菌膜、3%的涂膜抗菌膜较适合用于鲜肉包装,其中2.5%无机抗菌膜对大肠杆菌繁殖的抑制效果最佳。     

氧弹燃烧-离子色谱法测定一次性食品接触用生物基塑料中氟含量

目的 建立并优化氧弹燃烧-离子色谱法测定一次性食品接触用生物基塑料(下文简称生物基塑料)中氟含量的检测方法,分析市售生物基塑料产品中氟含量情况。方法 生物基塑料经氧弹燃烧发生高温氧化分解,氟化物转化为游离态氟离子,被吸收或溶解在吸收液中,以5.0 mmol/L碳酸氢钠和1.0 mmol/L无水碳酸钠溶液作为流动相进行等度洗脱,进样量为20μL,流速为0.8 mL/min;采用Metrosep A Supp 7色谱柱(250 mm×4.0 mm, 5.0μm)和Metrosep A Supp 5 Guard保护柱(50 mm×4.0 mm, 5.0μm),柱温为45℃;以电导检测器进行测定,外标法定量。结果 氧弹燃烧-离子色谱法测定生物基塑料中氟含量的相关系数R²>0.995,检出限为5.0 mg/kg,定量限为10 mg/kg,线性关系良好,加标回收率为93.8%～98.4%,精密度为2.9%～6.8%(n=6)。通过对119款实际样品中氟含量进行定量分析,总体检出率为94.11%,总体不合格率为15.94%;PLA吸管、PLA+PBAT吸管和PLA+PBS...     

Rietveld全谱拟合法计算石灰石中碳酸钙和结晶硅含量

为探索检测水泥生产主要原料石灰石主次物相含量的更加便捷科学的方法,提出利用基于TOPAS软件的Rietveld全谱拟合法对3种石灰石样品中碳酸钙和结晶硅的含量进行定量分析。以传统化学滴定结果为基准,将所得测试值与综合热分析结果分别与基准进行对比可知,对石灰石中主晶相碳酸钙含量的计算值比综合热分析更接近传统的滴定分析结果,最大百分偏差约为1%,而对副晶相二氧化硅含量的计算值比化学分析结果偏低且百分偏差在4%以上。结果表明,Rietveld全谱拟合法对石灰石样品中碳酸钙主相的计算更加科学合理,对结晶硅含量计算精度稍差,但是相比于传统滴定法和热分析法更有助于判定石灰石的易烧性。     

碳酸钙增强淀粉/木质纤维复合材料的制备工艺及性能表征

目的 制备碳酸钙增强淀粉/木质纤维复合材料，研究配方、制备工艺对其性能的影响规律。方法 以碳酸钙为填料，木薯淀粉为基材，木质纤维为增强体，采用模压成型方法制备淀粉/木质纤维复合材料，通过力学、吸水性能测试，以及傅里叶变换红外光谱（FT-IR）、X-射线衍射仪（XRD）、热重分析仪（TGA）和扫描电子显微镜（SEM）等测试手段，表征碳酸钙填料含量、成型温度对制备的复合材料性能的影响。结果 碳酸钙添加量为60%（质量分数）、成型温度为160℃时制备的复合材料拉伸、抗弯和压缩性能最佳，分别达到了2.4 MPa、7.3 MPa和3.1 MPa，弹性模量也达到985.5 MPa。同时红外光谱、热重分析及扫描电镜等表征证明此条件下制备的复合材料形成了更均匀的网络结构。结论 最佳条件下制备的碳酸钙增强淀粉/木质纤维复合材料同时具有较优异的力学性能、耐水性、热稳定性和生物降解性。     

环境条件对中密度纤维板密度测试结果的影响初探

通过试验,分析比较标准平衡环境条件和模拟冬、夏季环境条件3个温湿度平衡处理对样品物理性能的影响。数据表明：当温度在（20－30）℃、相对湿度在（65－85）％范围内变化时,对密度的测试结果没有影响,但密度偏差有变化;当温度在（15—20）℃、相对湿度在（35～65）％范围内变化时,密度偏差有变化,并且对密度的测试结果平均值有影响。     

高温燃烧吸收-离子色谱法测定氟醚橡胶中氟溴

采用高温燃烧吸收仪与离子色谱仪联用技术,建立同时测量氟醚橡胶中氟溴含量的方法。优化的实验条件为:燃烧炉燃烧管进口温度为850℃,出口温度为1 000℃,称样量为10 mg,以0.05 mol/L氢氧化钠为吸收液,0.02 mol/L氢氧化钾为淋洗液,采用抑制型电导检测器。氟离子在1～100 mg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数r~2=0.999 3,检出限为0.04%,回收率为93.0%～104.1%。溴离子在0.1～10 mg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数r~2=0.999 6,检出限为0.005%,回收率为94.0%～104.0%。与传统氧瓶燃烧、氧弹燃烧-离子色谱法相比,该方法方便、快捷,可连续处理样品,在30 min之内即可完成样品的检测。     

专利信息

摘要一种氢氧化铝阻燃剂的制备方法。涉及用作阻燃剂的一种氢氧化铝粉体的表面包覆改性处理方法。其特征在于将铝酸钠溶液进行净化后，加入选自碳酸钙、硅酸盐、磷酸盐的无机添加剂进行包覆处理；再加入2％～12％的含磷基硅烷或钛酸脂表面改性剂，进行有机化改性处理。本发明方法制备的氢氧化铝粉体表面经多层包覆改性及无机一有机多层包覆改性处理，其热稳定性大大提高。分析结果表面经无机．有机包霜后初始脱水温温度245℃。     

铌酸锶钡陶瓷材料的制备及介电性能研究

以BaCO3，SrCO3和Nb205作为原料，采用高能球磨工艺制备SBN50陶瓷粉体。球磨后的粉体不经煅烧，直接压片成型，在1250～1350℃下保温1．5～12h可制备出SBN50陶瓷材料，并对此进行了X射线衍射分析、扫描电镜观察和性能测试。结果表明：球磨30h的粉体在1100℃时合成SBN50单相；随着烧结温度的升高和保温时间的延长，SBN50陶瓷的介电常数先增大后减小，晶粒大小呈有规律的变化。1300℃下保温3h制得的陶瓷样品介电常数最高（εmax=1447），居里温度（L）为130℃。     

ICP-AES/ICP-MS快速测定垃圾焚烧飞灰样品中金属元素含量

为准确分析垃圾焚烧飞灰中金属元素含量,解析元素污染特性,建立采用HNO3+HF+HClO4体系湿法消解样品,电感耦合等离子体发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)测定样品中金属元素含量的方法。采用国家标准物质GBW07423模拟基体复杂的垃圾焚烧飞灰样品,验证方法的准确度和精密度,进行过程质量控制。研究结果表明,各元素线性拟合良好,分析结果与标准值吻合。实际样品分析中,ICP-AES测试的相对标准偏差为0.76%～6.91%;ICP-MS测试的相对标准偏差为0.50%～3.40%,测试精密度良好。该方法具有前处理流程简单、多元素同时测定、线性范围宽、分析效率高等优点,可满足不同类型垃圾焚烧飞灰样品中金属元素含量的分析。     

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.