干电池电液中钴的测定

在本法中,钴不经分离,在与电液相同的pH下与亚硝基R盐直接显色。本法易于操作,所用仪器简单,吸收线性好,灵敏度高,回收理想,适于有关厂家及研究者普遍使用。     

Rietveld structure refinement,cations distribution and magnetic features of CoFe2O4 nanoparticles synthesized by co-precipitation,hydrothermal, and combustion methods

Cobalt ferrite nanoparticles were synthesized by chemical co-precipitation, hydrothermal and sol gel auto-combustion methods. X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM) were used to investigate the structural characteristics and magnetic properties of cobalt ferrite nanocrystals. X-ray patterns revealed the production of a broad single cubic phase with the average crystallite size of 16, 18 and 178 nm for co-precipitation, hydrothermal and combustion methods, respectively. The FTIR measurements between 400 and 4000 cm⁻¹ confirmed the intrinsic cation vibrations of spinel structure. The FE-SEM micrographs of the synthesized samples indicated the presence of two distinct groups of grains exhibiting different sizes and, different shapes for hydrothermal route. The results of magnetic hysteresis at a room temperature showed that the magnetic properties depend on the particle size and shape of particles, whereas the role of particle size is more significant.     

钴基高温合金DZ40M高温高周疲劳过程中碳化物的行为

研究了ＤＺ４０Ｍ合金９００℃高周疲劳过程中碳化物的行为,在９００℃疲劳试验过程中,ＤＺ４０Ｍ合金中初生碳化物Ｍ７Ｃ３和ＭＣ发生溶解,同时,沉淀析出大量细小的二次碳化物Ｍ２３Ｃ６,它与其他具有立方取向关系。Ｍ２３Ｃ６相钉扎位错及亚晶界,强化合金基体,提高形变抗力。初生碳化物发生了断裂,降低了疲劳断裂抗力。ＤＺ４０Ｍ合金表面发生了严重的氧化,优先氧化的碳化物是疲劳裂纹源。     

Co/SiO2催化剂上CO加氢合成液态烃研究——反应条件的影响

采用初湿法制备了Co/SiO2 催化剂 ,并对催化剂进行了TPR研究及XRD表征 ,发现在焙烧后的催化剂上 ,Co主要以Co3O4 物种的形式存在 ,其还原过程分两步进行 :Co3+→Co2 +→Co0 。考察了Co负载量、反应温度、压力、空速等条件对催化剂活性的影响 ,结果表明 ,费托合成反应受条件的影响非常大。对合成液态烃适宜的反应条件为中温、中压及较低的空速     

钴源退役过程的辐射防护与剂量监测

辐照技术的应用日益广泛,辐射源的退役也越来越受到关注。苏南某单位辐照室建立于20世纪80年代初,2001年4月对最早投入运营的39根钴源进行退役,退役过程分三个阶段,历时48小时。由于经过了精心的准备,采取了有效的防护措施,退径过程没有出现工作人员受超剂量照射的情况。     

Comparative study of chelating ion exchange resins for the recovery of nickel and cobalt from laterite leach tailings

Commercially available chelating resins with the iminodiacetate functional group have been evaluated for their suitability for the adsorption of nickel and other metal ions by a resin-in-pulp process from the tailings of a pressure acid leach process for nickel laterites. The Amberlite IRC 748 and TP 207 MonoPlus resins were found to be the most suitable in terms of loading capacity for nickel and kinetics of adsorption. The resin with the highest nominal capacity was observed to adsorb less nickel as a result of the adsorption of greater amounts of the impurity ions. The equilibrium loading for nickel on the preferred resin was found to be similar from the ammonium and protonated form of the resin although the kinetics of adsorption is greater when the resin is initially in the ammonium form. A study of the kinetics of the loading of nickel and cobalt from pulp has shown that the rate can be described in terms of a first-order approach to equilibrium. The optimum pH for adsorption was found to be in the range 4 to 5 as this pH is high enough to maximize the adsorption of nickel and cobalt while preventing precipitation of nickel and cobalt as hydroxides from the pulp. A method for minimizing the competition from more strongly loaded ions such as iron(III) and chromium(III) which are present in the pulp was also developed in the initial laboratory phase of the study.     

提高复杂铜钴矿石浸出率的试验研究

本文对某复杂铜钴矿石进行了提高浸出率的试验研究.试验通过硫酸浸出的方法浸矿,研究了各因素对铜钴矿浸出效果的影响,并获得了最优浸出条件.与现有工艺相比,本试验中铜、钴的浸出率得到明显提高.     

聚乙二醇-硫酸钠-硫氰酸钾体系中Co(Ⅱ)、 Ni(Ⅱ)、 Mo(Ⅵ)的萃取分离研究

用硫氰酸钾作萃取剂，探讨了在聚乙二醇（ＰＥＧ）２０００硫酸钠硫氰酸钾双水相体系中Ｃｏ（Ⅱ）、Ｎｉ（Ⅱ）、Ｍｏ（Ⅵ）等金属离子的萃取行为。控制一定条件，实现了Ｃｏ（Ⅱ）与Ｎｉ（Ⅱ）、Ｃｏ（Ⅱ）与Ｍｏ（Ⅵ）及Ｃｏ（Ⅱ）与Ｎｉ（Ⅱ）、Ｍｏ（Ⅵ）混合离子的定量分离，并研究了不同类型的表面活性剂对ＰＥＧ相萃取行为的影响。     

抑制HSP90对缺氧肿瘤细胞辐射敏感性的影响

为研究抑制HSP90对缺氧模拟剂(CoCl2)处理的人宫颈癌Hela细胞的辐射敏感性影响,分别用不同浓度的CoCl2处理Hela细胞24 h进行模拟缺氧处理,用不同浓度的HSP90特异性抑制剂17-DMAG预处理细胞16 h,应用γ射线照射细胞,照射剂量分别为2、4、6和8 Gy,采用克隆形成实验观察细胞的存活率,用Western blot实验检测HIF-1α蛋白表达量变化,用激光共聚焦显微镜观察细胞凋亡情况。结果显示:用CoCl2处理细胞可以诱导HIF-1α蛋白过表达;不同浓度17-DMAG处理组的Hela细胞在不同照射组间的存活率差异具有显著性(p<0.01);17-DMAG预处理缺氧Hela细胞后,HIF-1α蛋白表达随药物浓度增加受到显著抑制,细胞早、晚期凋亡率随药物浓度增加而增加。结果表明:17-DMAG预处理模拟缺氧细胞可增加细胞辐射敏感性并促进细胞凋亡,其机制可能是通过抑制HIF-1α蛋白表达而发挥作用。     

Electrodeposition of cobalt–tungsten alloys from alkaline citrate containing bath as alternative for chromium hexavalent replacement

Abstract

Cobalt–tungsten alloys have been considered as potential materials for various applications. This work investigates the wear and corrosion resistance behaviour of cobalt–tungsten–phosphorus alloys electroplated from alkaline citrate containing baths. The wear rates of the cobalt–tungsten alloy electrodeposits were lower than those of the unalloyed cobalt electrodeposits. The wear rate was also lower than those of chromium plated from hexavalent chromium plating bath. It was also demonstrated that the addition of small quantities of phosphorus into Co–W alloys improved the corrosion resistance of the alloy. In fact, the addition of phosphorus further improved the corrosion of the alloy exposed to immersion test in comparison to cobalt–tungsten. The cobalt–tungsten alloys without having any phosphorus component were subjected to further oxidation of tungsten component followed by dissolution in deionised water during the immersion tests.

On a considéré des alliages de cobalt et tungstène comme matériaux potentiels pour diverses applications. Ce travail examine le comportement d’usure et de résistance à la corrosion d’alliages de cobalt, tungstène et phosphore déposés par électrolyse, à partir de bains alcalins contenant du citrate. Les taux d’usures des dépôts de l’alliage de cobalt et tungstène étaient plus faibles que ceux des dépôts non alliés de cobalt. Le taux d’usure était également plus faible que ceux de chrome déposés à partir d’un bain de dépôt électrolytique de chrome hexavalent. On a également démontré que l’addition de petites quantités de phosphore dans les alliages de Co–W améliorait la résistance à la corrosion de l’alliage. En fait, l’addition de phosphore améliorait davantage la corrosion de l’alliage exposé à un essai d’immersion par rapport à l’alliage au cobalt et tungstène. Les alliages de cobalt et tungstène, sans la composante de phosphore, étaient sujets à davantage d’oxydation de la composante de tungstène suivie par la dissolution dans de l’eau déionisée lors des essais d’immersion.