用ICP-AES法测定氰化镀银溶液中铜、铁、铅、镉、钙、镁含量

以硝酸和盐酸破坏银氰化合物,使氰化物和银分别以氢氰酸气体和氯化银沉淀形式除去,用ICP-AES法连续测定了铜、铁、铅、镉、钙、镁的含量.结果表明,方法检出限为0.001 5～0.110 0 μg/mL,加标回收率在89%～124%之间.用于氰化电镀银溶液杂质元素测定,结果令人满意.     

氰化镀银光亮剂研究现状及发展

介绍了生产中应用的各种氰化镀银光亮剂的研究现状和其发展趋势，并探讨了各种光亮剂的作用机理，并对新型氰化镀银光亮剂的研究提出了设想。     

氰化镀银光亮剂的研究现状及发展

介绍了生产中应用的各种氰化镀银光亮剂的研究现状和其发展趋势，并探讨了各种光亮剂的作用机理，并对新型氰化镀银光亮剂的研究提出了设想。     

高稳定性无氰镀银工艺研究

针对传统氰化镀银工艺存在的毒性及职业健康风险,开展了无氰镀银工艺研究。通过Hull Cell试验以及对试验现象的观察比较,确定并优化了无氰镀银的工艺参数。结果表明：该工艺在35～45℃,pH值为9.0～10.0,0.1～1.2 A/dm²的电流密度下,可以获得外观平整、纯度高、均匀光亮的镀银层,且镀液具有稳定性好、电流效率高等优点,具有市场应用潜力。     

氰化镀硬银光亮剂

探讨了氰化镀银液中光亮剂的配制，并对其进行了性能测试。结果表明，研制的光亮剂基本达到使用要求。     

镍基高温合金镀银工艺

航空工业中 ,高温合金零件镀银主要用于防止高温粘结。由于镍基高温合金含镍量高 (≥ 50 % ) ,而且加入了抗氧化性能很强的铬、钛、铝等元素 ,其表面很易生成一层连续、致密的金属氧化物薄膜 ,具有较高的热稳定性。所以 ,在生产中 ,如何使基体金属完全暴露 ,又不使基体过腐蚀 ,成为镍基高温合金镀银工艺中的关键问题。1　工艺流程装挂→氰化除油→水洗→活化→水洗→预镀镍→水洗→氰化镀铜→水洗→镀银。( 1)氰化除油　Ｎａ2 ＣＯ32 0～ 30ｇ/Ｌ ,ＮａＣＮ 2 0～ 4 0ｇ/Ｌ ,阳极　不锈钢板 ,温度　室温 ,Ｄｋ1.0～ 1.5Ａ/ｄｍ2 ,先阴极除油…     

氢化物-冷原子吸收法测定土壤和植物中的汞

通过灯电流、载液、还原剂浓度及其流速、氧气流速的条件实验来确定仪器的最佳工作状态。然后采用五氧化二钒-硝酸-硫酸体系，在80℃水浴中消解土壤、植物样品，再用流动注射-氢化物发生石英管冷原子吸收系统测定样液中的汞。该方法的分析结果可靠，回收率达93．8％～100．3％，灵敏度为0．29μg／L／1％，检出限为0．039μg/L，相对标准偏差为（n=5）1．1％～5．3％，线性范围为0．5μg/L～50μg／L。     

ICP-AES同时测定废氰化镀金溶液中Au，Cu，Ni，Fe含量

为了快速测定废氰化镀金溶液中Au，Cu，Ni，Fe四种元素含量，采用一步消解直接进行ICP-AES测定。并对分析谱线、元素干扰和等离子体参数进行了讨论。结果表明，方法检出限为0．014—0．019μg／ml，加标回收率在97．3—101．0%之间，相对标准偏差（RSD）小于2．54％。该方法准确、快速、简便。应用于废氰化镀金溶液的回收生产，结果令人满意。     

烟酸镀银

上海机电二局电镀队试验成功烟酸镀银。其镀液性能,除分散力稍差外,其他如深度外力、沉积速度均与氰化镀银相当;镀层结合力、硬度、脆性均达氰化镀银水平,而且镀层能观更加光亮,耐腐性能亦更优良。     

氢化物-原子荧光光谱法依次测定锌精矿中砷、锑、铋、锡

用氢化物～原子荧光光谱法，一次性分解样品，在L2半胱氨酸存在下，实现了锌精矿中As、sb、Bi、Sn的连续测定。其回收率分别为93．8％～104．0％、95．0％～108．3％、93．0％～110．6％和95．7％～104．7％；检出限分别为0．35、0．31、0．19和0．35μg／L。用该方法分析锌精矿样品，结果满意。     

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.     

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.     

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.     

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.