用膜相渗透化学镀法制备NiCo/PTFE磁性复合膜

为促进金属粒子在膜孔中生成,采用膜相渗透和化学镀结合的方法,研究了化学镀NiCo/PTFE磁性复合膜的工艺.在正交试验结果基础上探讨了主盐离子浓度比、NaOH浓度、N2H4浓度、反应温度和反应时间对NiCo/PTFE复合膜中金属含量和磁性能的影响.本工艺最佳配方为:0.14 mol/L CoCl2·6H2O,0.06 mol/L NiCl2·6H2O,0.90 mol/L NaOH,0.45 mol/L C4H4O6KNa·4H2O,0.45 mol/L N2H4·H2O;最佳参数为:70～75℃,75 min.结果表明,相对于传统的双面金属化处理,引入膜相渗透的单面活化有助于镍钴金属粒子在膜孔内原位生成.     

钼粉表面化学镀铜工艺研究

采用化学镀方法对平均粒径3 μm的Mo粉末进行化学镀铜,探讨了工艺条件对化学镀铜的影响.利用扫描电镜(SEM)对钼粉镀覆前后形貌进行观察;X射线衍射(XRD)对所得复合粉末相组成进行了分析.结果表明:采用化学镀的方法可以成功地获得铜含量(质量分数)为15%～85%的Mo/Cu复合粉末,复合粉末中无Cu2O,表面平滑,但有团聚现象;化学镀铜过程中,pH值的临界值为12,随着pH值增加,镀速加快,但是pH值过高会引起甲醛分解,镀液中pH值的最佳范围在12～13之间;随着温度和甲醛含量的升高,镀速加快,镀液稳定性降低,镀液中甲醛含量和温度最佳范围分别为22～26 mL/L,60～70℃.     

影响碳纤维表面镀铜速率的因素

在碳纤维表面先化学镀铜再电镀铜可获得具有一定厚度且均匀的铜镀层.研究了甲醛、配位剂、稳定剂等用量、pH值、温度、电流密度、电解时间等对碳纤维增重率的影响,确定了镀铜的最佳配方,并用扫描电镜验证了镀铜效果.结果表明,最佳化学镀铜配方为16 g/L CuSO-4·5H-2O,25 g/L EDTA·2Na,15 g/L酒石酸钾钠,15 g/L NaOH, 5 mg/L 2,2′-联吡啶,15 mg/L K-4Fe(CN)-6,6 mL甲醛(分析纯).本法既较好地解决了碳纤维束的黑心问题,又可获得较厚的镀层,且镀层与碳纤维的结合更牢.     

化学镀铜法制备纳米Cu-Al2O3复合粉体的研究

采用化学镀方法在超声波辐照下对10－20nm的Al2O3粉末进行化学镀铜，并探讨了镀液组成及工艺条件对纳米Al2O3粉末化学镀铜的影响，利用X射线衍射判断其成分组成，用TEM观察镀覆结果，结果表明：引入超声波并调整镀液组成和工艺条件可以实现室温的纳米Al2O3粉末化学镀铜，使化学镀鲷在低温下保持了镀液的稳定性，同时对纳米粉末进行有效的分散；以EDTA－2Na为络合剂，并加入亚铁氰化钾和2－2联吡碇作为稳定剂，可以有效地消除或减少复合粉末中的Cu2O.通过改变低温超声波化学镀铜时的镀液组成和装载量，可以一次镀覆得到铜含量为5％－90％的Cu-Al2O3复合粉末。     

智能金属结构中光纤表面金属化的研究

为了把光纤传感器埋入金属材料中,需要对光纤传感器进行保护.为此,提出了一种无粗化的光纤表面化学镀工艺,并根据其后续处理的特点,用镀层的结合力、电性能、光亮度以及镀速四个性能指标对化学镀工艺采用正交试验方法进行了优化,获得了最佳化学镀工艺为:25 g/L NiSO4·6H2O,20 g/LNaH2PO2·H2O,20 mL/L C3H6O2,20 g/L H3BO3,1 g/L NaF,2 mg/L糖精,2 mg/L硫脲,pH值4.5,温度86℃.该工艺下所得镀层为非晶态N-P镀层,与光纤有较好的结合力.     

玻璃纤维化学镀Co-P合金工艺研究

为了提高导电玻璃纤维的电、磁性能,拓宽其应用领域,采用化学镀的方法,研究了在玻璃纤维表面镀Co-P合金的工艺,探讨了化学镀液的主盐、温度、pH值及施镀时间等工艺参数对化学镀Co-P合金成分及镀速的影响.本工艺的最佳配方为:18 g/L CoSO4,18 g/L NaH2PO2*H2O,45 g/L柠檬酸钠,29 g/L (NH4)2SO4;最佳参数:温度为90 ℃,pH值为9,施镀时间为50 min.在此工艺条件下镀液的稳定性较好,镀层沉积速度快、光亮、致密,所得镀层为非晶结构.     

化学镀Ni-Co-P合金工艺研究

为了改善化学镀Ni-Co-P合金工艺存在的镀速慢、镀层质量差等问题,研究了镀液组分、表面活性剂、pH值、稳定剂、配位剂对化学镀Ni-Co-P合金镀层沉积速度、耐蚀性、孔蚀率的影响,得出最佳镀液配方和工艺:26 g/L CoSO4,28 g/L NiSO4,22 g/L NaH2PO2,80 g/L Na3C6H5O7,69 g/L(NH4)2SO4,1 mg/L KI,50 mg/L十二烷基苯磺酸钠,pH=8,温度85℃.本研究结果为化学镀Ni-Co-P合金工艺提供了依据,较有实用价值.     

化学镀中环氧树脂封装材料粗化的研究

研究了在环氧树脂封装材料表面进行化学镀铜时前处理过程中最佳粗化工艺条件:300 g/L CrO3,225 mL/L H2SO4,温度85℃,时间30 min.对粗化后的环氧树脂封装材料表面进行了SEM形貌分析、表面粗糙度及表征亲水性的接触角的计算.结果表明,采用的化学粗化工艺适用于此种环氧树脂基材料,在最佳工艺条件下可以得到较好的化学镀铜层,镀层与样件表面的结合力达到5B级,且镀层能起到较好的电磁屏蔽效果.     

SiC颗粒化学镀铜工艺研究

化学镀铜在生产中应用比较广泛,但是在化学镀铜过程中的活化工艺所需试剂有毒,并且价格较为昂贵。探讨了取消化学镀铜过程中的活化工艺后,其他工艺条件对Si C镀铜效果的影响规律。经实验分析,获得了化学镀铜实验优化工艺参数为:化学镀铜溶液温度为35℃,溶液p H值用氢氧化钠调节至12~13,硫酸铜加入量为12 g/L,甲醛加入量为28 ml/L,酒石酸钾钠加入量为40 g/L,经过一定时间在碳化硅表面得到了良好的铜镀层。通过X射线衍射仪及扫描电镜检测,结果表明:取消了活化工艺后,在碳化硅表面仍然得到了较好的铜包覆层。     

硅粉表面化学镀铜工艺研究

研究了化学镀法对硅粉进行化学镀铜过程,探讨了甲醛含量、pH值、温度对化学镀铜反应时间及复合粉体颜色的影响和镀层的微观形貌及结构。结果表明：在镀液中,pH值增大、温度升高、甲醛含量增加,可以缩短反应时间,提高镀速。得出最佳工艺条件：甲醛为60～72ml／L,pH值为12～12．5,60℃。所得复合粉体镀覆均匀,晶形良好,没有Cu2O的存在。     

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.     

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.     

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.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.