双膜三室同槽电解金属锰和微粒电解二氧化锰的控制因素

采用双膜三室电解法同槽电解金属锰和微粒电解二氧化锰,同时中隔室回收硫酸。分别研究了Mn~(2+)浓度、电流密度、电解温度、阴极(NH_4)_2SO_4浓度、阳极H_2SO_4浓度对电沉积效果的影响。结果表明:在阴极Mn~(2+)浓度40 g/L、初始pH=6.9、(NH_4)_2SO_4浓度110 g/L、电流密度400 A/m~2,阳极Mn~(2+)浓度40 g/L、H_2SO_4浓度2.5 mol/L、电流密度800 A/m~2,极间距90 mm,电解温度45℃,电解时间5 h条件下,阴极电流效率可达77.53%,能耗为6 725.28 kW·h/t,阳极电流效率可达84.87%,能耗为3 883.91 kW·h/t,酸回收率达到63.2%。阴极产品金属锰表面光滑平整,晶粒为块状,呈层状堆积,阳极产物微粒电解二氧化锰颗粒细小,粒径分布均匀,有较规则的晶体形貌。     

隔膜电解体系内苯酚降解效果的研究

制备了碳、聚四氟乙烯质量比为4:1的C/PTFE气体扩散电极,并将其作为阴极与Ti/RuO2阳极构成电解槽,在阴阳极之间放置纯棉隔膜,在0.1mol/L Na2SO4溶液中电解20分钟,阴极室HO2-浓度为56mg/L.将隔膜电解槽应用于苯酚的电催化氧化,研究了阴、阳极协同作用电催化氧化降解水中苯酚的效果.实验结果表明,在电解反应初期,苯酚去除效率及COD和TOC的去除率随着电解时间的增加而增大,电解80分钟后,三者的变化趋势减缓,电解100分钟后,阴极室、阳极室苯酚的去除率分别为92%、97%;阴、阳极室COD去除率分别达到86%、70%;TOC去除率分别达到84%、68%.阴极室内,氧在阴极还原生成的碱性过氧化氢(HO2-)导致苯酚的矿化效果优于阳极的氧化作用.     

单膜双室同槽电解金属锰联产EMD离子的传输机理研究

针对传统布式隔膜袋电解技术工艺中存在的诸多弊端,本研究提出了单膜双室膜电解工艺,以MnSO4+(NH4)2 SO4为电解液体系,实现在阴极产锰的同时在阳极联产电解二氧化锰,并在阳极室中回收硫酸.通过测定阴阳极室中各离子成分的变化情况,来深入分析电解过程中的离子传输行为,以验证单膜双室同槽电解的技术可行性.实验结果表明:单膜双室电解法能够有效实现同槽电沉积金属锰并联产电解二氧化锰,同时在阳极室中回收硫酸,硫酸浓度可达1.5 mol/L,满足前端锰矿酸浸工艺要求,促进了对资源的高效回收利用.采用TRJAM-10W阴离子交换膜的阴极产锰率和阳极酸回收率最高,分别可达77.0％和64.3％,而采用Ionsep-HC阴离子交换膜的阳极产EMD率最高,为27.3％.TRJAM-10W阴离子交换膜的槽电压最小,为4.43 V,其电能消耗也最低,为5607 kW·h·t-1.     

双极膜电槽与变频不对称脉冲方波技术在电合成高铁酸盐中的应用

在CS-CMC双极膜电槽中,以多孔圆筒铸铁为阳极,结合变频不对称脉冲方波技术电解制备水处理剂高铁酸盐。IR分析表明,该聚合物膜两极分别含有-N=CHR、-COO-官能团。CS-CMC双极膜的溶胀率较小,能稳定存在于浓酸、浓碱溶液中。在电极上迭加变频不对称脉冲方波可及时去除阳极表面的氧化膜。与平板铸铁阳极电解槽相比,多孔圆筒铸铁阳极电解槽可得到更高的电流效率和更高浓度的高铁酸盐。在14 mol/L的NaOH溶液中,室温以5 mA/cm2的电流密度、脉冲方波频率2 Hz电解6 h,电流效率平均为51.1%,高铁酸盐浓度达37 mmol/L。     

涂液浓度对IrTaSnSb钛基氧化物阳极析氯活性的影响

采用热分解法及不同浓度涂液制备了IrTaSnSb钛基阳极,使用扫描电镜观察阳极微观表面形貌,采用电化学方法研究了析氯活性,并测试了电流效率和强化电解寿命。结果表明,不同涂液浓度制备的阳极表面形貌存在明显差别,导致析氯活性随着涂液浓度的增大呈现先升高后降低的趋势;0.30 mol/L涂液制备的阳极电流效率最高,这是因为细小均匀的裂纹增加了涂层的真实活性表面积,提高了阳极析氯活性;在阳极涂层载涂量接近情况下,低浓度涂液制备的阳极表面较平整致密,钛基体不易被氧化生成TiO_2钝化膜,强化电解寿命最长。综合考虑,0.30 mol/L涂液制备的阳极具备较高的析氯活性和强化电解寿命,此浓度是较理想的涂液浓度。     

脉冲电流法制备聚苯胺/纳米银复合膜

以高导电率的Ag作为添加材料 ,首次采用换向脉冲电流法使PANI和Ag发生共沉积 ,制成PANI/Ag复合电极。并用循环伏安研究了复合电极在硝酸溶液中的电化学性能及沉积过程中电化学参数对膜层电化学性能的影响。当Ag 浓度为 0 0 1mol/L ,苯胺浓度为 0 3mol/L ,沉积平均电流密度为 3～ 4mA/cm2 ,且脉冲阳极峰电流和阴极峰电流比值适当时可获得电化学性能最为优异的膜层。     

Binary System MnO-Nb_2O_5

The phase diagram of the binary systemMnO-Nb_2O_5 was studied by means of the differentialthermal analysis(DTA),X-ray diffraction analysis andscanning electron microscopy(SEM).Thermodynamic da-ta of the new compounds 4MnO·Nb_2O_5 andMnO·Nb_2O_5were found as follows:4MnO·Nb_2O_5:t_m=1398±2℃△H_m=129000(J/mol)△S_m=77(J/mol,K)△G_m~o=129000-77T(J/mol)MnO·Nb_2O_5:t_m=1499±2℃△H_m=86940(J/mol)△S_m=49.6(J/mol,K)△G_m~o=86940-49.6T(J/mol)The eutectic parameters for the system are given below:t_(E1)=1383±3℃ N_(E1(MnO))=0.896t_(E2)=1312±2℃ N_(E2(MoO))=0.713t_(E3)=1400±4℃ N_(E3(MnO))=0.231     

TC4钛合金表面阳极氧化制备TiO_2多孔膜的实验研究

以硫酸为电解液,钛合金(TC4)为阳极,不锈钢片为阴极,采用恒压的氧化方式在钛合金表面获得TiO2多孔膜。通过扫描电镜(SEM)观察了多孔膜的微观形貌并用X射线衍射(XRD)对覆在钛合金基体上的氧化膜进行了物相分析,研究了氧化工艺参数电压、阳极氧化时间和硫酸浓度对TiO2多孔膜相组成的影响。结果表明:TC4钛合金阳极氧化获得的氧化膜为非均一平面的TiO2多孔膜,且膜的孔径分布在90~240nm,XRD分析表明在不同的氧化工艺参数下氧化膜均由锐钛相和金红石相双相晶型组成。在0.5mol/L硫酸溶液中,电压高于100V或氧化时间长于5min即出现锐钛相和金红石相TiO2,随着电压的升高和时间的增长金红石相TiO2的含量逐渐增加;在恒压120V时,硫酸溶液浓度为0.3mol/L即出现锐钛相和金红石相TiO2,随着硫酸浓度的提高金红石相TiO2的含量先增加后减少。     

Ni-P-mCMC/mCS双极膜的制备及在电合成糠醇中的应用

以磷酸化试剂改性羧甲基纤维素钠和戊二醛改性壳聚糖制备了Ni-P-mCMC/mCS双极膜并用于电还原制备糠醇。测定了膜的离子交换容量及膜的交流阻抗;以化学镀方法将金属镍镀在阳离子交换膜层的表面上,以实现阴极室中的零极距电解。双极膜中间层中水解离后生成的H+离子迁移入阴极室中,使阴极室呈酸性,从而保证了糠醛电还原生成糠醇的进行。实验结果表明,以糠醛水溶液为阴极液,1mol/LH2SO4为阳极液,常温电解,电流效率可达84%,电解电压2.5V。与传统的液相中压或高压加氢法相比,避免了Cu-Cr催化剂所产生的铬污染,为绿色环保工艺。     

中性水溶液中阴极电解制备自支撑通孔氧化铝膜

提出一种自支撑通孔有序氧化铝膜(AAM)的阴极电解制备方法.在中性氯化钾水溶液中,以AAM/Al为阴极,石墨为阳极,电压为-4～-5V,电解3～10min即可把氧化铝膜从铝基底上剥离,同时去除背面阻挡层,获得自支撑通孔氧化铝膜.讨论了通孔氧化铝膜电解制备方法的剥膜、通孔的机理.     

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.     

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.     

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.