碱性锌酸盐锌-铁合金电镀工艺

对德国科兹490锌-铁合金电镀工艺进行了全面介绍，包括工艺的特点、镀液的配制、镀液成分的作用、操作条件的影响、镀液的维护及其故障的排除。在镀槽中采用不溶性阳极可获得均匀的电流分布；采用辅助槽时，能得到综合性能最好的锌-铁合金镀层。     

碱性锌酸盐体系锌-铁-二氧化钛复合电镀工艺的研究

通过在碱性锌铁合金电镀液中加入适量钛白粉，制得锌－铁－二氧化钛复合电镀层。介绍了镀液中各组分的作用及操作条件。研究了镀液中的氧化锌、氯化亚铁、二氧化钛、配合剂和添加剂的含量以及阴极电流密度、温度和搅拌等对复合镀层中铁和二氧化钛含量的影响，优选出最佳镀液组成及操作条件。结果表明，复合电镀过程中，二氧化钛与铁的沉积互相促进，具有协同效应。     

硫酸盐镀液电镀锌铁合金的研究

本文研究了硫酸盐镀液中添加剂、pH值、电解液成份对锌铁合金镀层的影响.初步获得了镀取含铁0.6%左右的光亮锌铁镀层的镀液成份和工艺条件.     

低铁锌铁合金电镀新工艺

研究了在碱性锌酸盐镀液中加入含铁补充剂后,得到镀层含铁量为0.4%～0.8%的锌铁合金电镀新工艺,讨论了影响镀层铁含量的各种因素,测试了镀层及镀液的性能.结果表明,锌铁合金镀层与锌镀层相比,更加光亮、细致,结晶致密,耐蚀性得到进一步提高.     

高耐蚀性光亮锌铁合金电镀

研究了光亮氯化物锌铁合金镀液与镀层的各主要参数，并在实际生产中得到验证。     

锌-铁合金镀液及镀层中锌、铁的快速测定

为了获得耐蚀性良好的锌一铁合金镀层，必须维持镀液中锌、铁含量在一定的工艺范围内。采用EDTA滴定和分光光度相结合的方法测定碱性锌一铁合金镀液中的锌、铁含量，并优选出最佳测量波长。研究了酸度、显色剂浓度、共存组分及干扰元素对测量结果的影响；结果表明：铁在0～6μg／mL范围内遵守比尔定律。该方法简便快速、准确度高能满足实际生产的要求。     

汽车零部件锌铁合金滚镀工艺

为适应国家有关淘汰含氰电镀的规定,提出以氯化物锌铁合金电镀工艺替代含氰电镀：某厂汽车零部件滚镀自动线采用锌铁舍金新工艺取代了原氰化滚镀锌工艺：介绍了锌铁合金滚镀工艺及各工序配方,探讨了滚镀液各组分、pH值、阴极电流密度对锌铁合金镀层的影响比较了锌铁舍金滚镀工艺与原氰化工艺的实践应用,表明锌铁舍金滚镀工艺镀层防护性能优、耗电少、生产效率高、成本低,已成功应用于汽车零部件的滚镀自动线。     

葡萄糖酸盐体系电镀镍铁合金的研究

本文研究以萄葡糖酸盐为络合剂的镀液中镍铁合金的电沉积。通过试验选择了合理的配方和操作条件。对镀液、镀层的有关性能进行了测定。并用电位扫描方法研究了合金沉积的电极为程及添加剂的作用。对葡萄糖酸盐体系、柠檬酸盐体系、抗坏血酸体系三种镀液的极化性能亦作了比较。     

防护装饰性节镍电镀新工艺的应用

1 概述 电镀锌铁合金是代镍、节镍电镀的一个研究方向.20世纪70年代研究的锌铁合金镀液为焦磷酸盐型,其锌铁合金镀层仅作装饰镀铬的底层,且需抛光或镀铜后才能套铬,工艺麻烦,电源要求严格,镀液也易出现故障,因而未用于生产.1988年,国际市场镍价成倍上涨,国内再次出现电镀锌铁合金研究热,取得成功,已在生产中应用[1].     

镍铁合金镀液

本专利阐述一种镍铁合金电镀液,其某些具体组分的量可以有效地控制。这些组分具有增效作用,使镍铁合金沉积非常光亮,具有很好的整平性。同时,这种镍铁合金槽液操作比较稳定,可以容许添加比较多的铁和有机添加剂,它的控制简单,用途广泛。镀液的基本组分足以产生所需镀层的有效量的镍离子与铁离子。此外,镀液的成分还有:酒石酸盐络合剂,还原性糖化物;大约0.5—3克/升的抗坏血酸、异抗坏血酸,它们的可溶于镀液的盐,或它们的混合物;控制量的缓冲剂,如硼酸和(或)醋酸钠;一级光亮剂(硫—氧和(或)含硫化合物)与二级光亮剂的组合。镀液的     

中温耐硫水解催化剂中三氧化钼的测定

采用硫氰酸盐分光光度法测定中温耐硫水解催化剂中三氧化钼含量,重点研究了试样处理方法、处理条件、酸度控制、抗坏血酸用量等测定条件对测定结果的影响.中温耐硫水解催化剂采用1#硫酸溶液溶解后,依次加入硫酸铁铵溶液、2#硫酸溶液、硫氰酸铵溶液及抗坏血酸溶液,用分光光度计测定其吸光度,从工作曲线查出或通过回归方程式计算出被测溶液中三氧化钼的质量.硫氰酸盐分光光度法测定结果与电感耦合等离子体发射光谱法基本一致,且成本低、操作快捷.     

L-抗坏血酸-2-棕榈酸酯钠的合成工艺研究

以L-抗坏血酸和棕榈酰氯为基本原料，以5，6-D-异亚丙基也-抗坏血酸为中间产物，在无水吡啶中进行酯化反应，经成盐和脱保护反应，制得最终产品。总收率为47％-51％。     

Electrochemical studies of magnetite coating on carbon steel in ascorbic and picolinic acid

Electrochemical impedance and cyclic voltammetric measurements of magnetite coating formed on carbon steel substrates were carried out in deaerated solutions of 1.0 × 10^–2 M ascorbic acid and 3.5 × 10^–2 M picolinic acid at 28 °C. Impedance data showed that the interaction between magnetite and ascorbic acid is associated with an incubation period, after which reductive dissolution takes place accompanied by oxidation of ascorbic acid. Once the magnetite film loses its thickness and protective properties on prolonged exposure to ascorbic acid, the charge transfer resistance and the capacitance is reduced. Initial dissolution of magnetite in picolinic acid is due to congruent chemical dissolution with little contribution from reduction by the electrons arising from the corrosive attack of acid on the carbon steel. With time the contribution of the latter process increases as more and more of the substrate opens up. Cyclic voltammetric studies showed that there is an adsorption phenomenon leading to the formation of a surface ferric complex that undergoes reduction to the ferrous species and transfers to the bulk solution. The accumulation of the ferrous ion accelerates the dissolution resulting in an increase in current. Dissolution of magnetite in picolinic acid is slow. The better complexing capability of picolinic acid compared to ascorbic acid does not permit the accumulation of the ferrous ion as indicated by the absence of a peak in the voltammogram.     

Precipitation characteristics of palladium from a simulated radioactive liquid waste by Ascorbic Acid

The precipitation characteristics of palladium (Pd) from a simulated radwaste solution by ascorbic acid was investigated. Pd was selectively precipitated by the reduction reaction of Pd with ascorbic acid. When the nitric acid concentration in the 8 component system was below 2.0 M, Pd over 99.5 % was selectively precipitated at an ascorbic acid concentration above 0.06 M, while other elements mainly remained in solution. The precipitation yield of Pd by ascorbic acid decreased with the increase of the nitric acid concentration.     

显色光度法测药物中的抗坏血酸含量

基于抗坏血酸将Fe3＋还原为Fe2＋,用邻二氮菲作Fe2＋的显色剂,用pH 5.4的六亚甲基四胺-HCl缓冲溶液调节体系酸度,建立了测定抗坏血酸含量的新方法,即显色光度法测定药物中的抗坏血酸。讨论了最佳的反应条件,结果表明抗坏血酸浓度在0～10μg/mL范围内符合比尔定律。此方法可应用于药品、合成样品中抗坏血酸含量的测定。     

Fabrication of a PANI/Au nanocomposite modified nanoelectrode for sensitive dopamine nanosensor design

Polyaniline/Au nanocomposite modified nanoelectrodes based dopamine nanosensors have been developed. The polyaniline/Au nanocomposite film was deposited at the exposed end of the nanoelectrode tip by a surface-graft polymerization method to fabricate a desired modified nanoelectrode. With this modified method, the nanocomposites firmly adhered on the electrode surface and the modified nanoelectrode still had a sharp tip, which was proved by the scanning electron microscope. The electrochemical measurement shows the polyaniline/Au nanocomposite modified film has a good and stable redox activity in neutral solution. The modified nanoelectrode exhibits the excellent electrocatalytic activity towards the oxidations of ascorbic acid and dopamine in phosphate buffer solution. The separation of anodic peak potential of dopamine and ascorbic acid reaches 250 mV. Differential pulse voltammograms results illustrate that dopamine can be selectively determined in the presence of thousands times higher concentration of ascorbic acid with a wide linear range from 200 to 0.3 μM and the detection limit is 0.1 μM. This study provides a simple method for the construction of dopamine nanosensors that have a good sensitivity, wide linear range and stable response. The nanosensors are hopeful to be applied to the detection of dopamine in vivo.     

Adsorption efficiency of poly(malachite green) films towards oxidation of ascorbic acid

Thickness of poly(malachite green) films electropolymerized on a glassy carbon electrode surface, the concentration of ascorbic acid, pH value of the solution, and accumulation time were found to affect the adsorption-controlled anodic peak current of ascorbic acid on this polymer film coated electrode. Adsorption efficiency, defined as the ratio of the active sites in polymer films to the amount of adsorbed ascorbic acid molecules, was then proposed and estimated from the comparison of mathematically simulated cyclic voltammograms with experimental ones. The concentration of ascorbic acid is the greatest parameter affected the adsorption efficiency. Poly(malachite green) film electropolymerized on the glassy carbon electrode was found to be not totally active towards oxidation of ascorbic acid when the concentration of ascorbic acid is too high or when the poly(malachite green) film is too thick. The potential shift of ascorbic acid on the modified electrodes was also discussed.     

Evaluation of ascorbic acid-loaded calcium phosphate bone cements: Physical properties and in vitro release behavior

In this study, different concentrations of ascorbic acid (50, 100 and 200 µg/mL) were added to the liquid phase of a calcium phosphate cement (CPC). The cements were immersed in simulated body fluid (SBF) for different intervals and physical, physicochemical and mechanical properties of them were evaluated. The release of added ascorbic acid from CPCs into the SBF solution was also studied. From the results, both setting time and injectability of CPC decreased by adding ascorbic acid, however the compressive strength was sharply increased before soaking in SBF solution. But, the compressive strength values of all cements (with or without ascorbic acid) soaked in SBF solution for more than 7 d duration were comparable. The X-ray diffractometry results showed that in vitro apatite formation ability of cement reactants did not change by adding ascorbic acid. The scanning electron microscopy images indicated that morphology of the formed apatite crystals was nano-needlelike and needle diameter was less than 100 nm. The loaded ascorbic acid was slowly released from CPC into the SBF solution so that about 10% and 20% of the loaded drug was released after 504 h for the cements containing 100 and 200 µg/mL ascorbic acid, respectively. The release rate was increased when the amount of added ascorbic acid decreased by 50 µg/mL.     

Controlled synthesis of copper nano/microstructures using ascorbic acid in aqueous CTAB solution

This paper describes a low-temperature green chemical synthesis of various morphologies of copper nano/microstructures. These syntheses achieved high yields in aqueous solution using ascorbic acid as a reductant and the cationic surfactant cetyltrimethylammonium bromide (CTAB) as a capping agent. The resulting copper particles were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and UV-Vis. absorption spectroscopy techniques. From the SEM analysis, it was found that different morphologies of copper particles, including submicron polyhedrons, micrometer rods, spherical nanoparticles, and nanowires were obtained by varying factors such as the molar ratio of reactants (ascorbic acid and CuSO₄·5H₂O), pH, reaction time, and temperature. Increasing the molar ratio of ascorbic acid to precursor salt and increasing the pH led to a decrease in the size of copper particles formed. At short reaction times, spherical copper nanoparticles with an average diameter of 90 nm are obtained. When the reaction time was prolonged, the nanoparticles transformed into nanowires with diameters in the range of 100-250 nm, and lengths of up to 6-8 μm. When the reaction temperature was decreased, Cu mixed with Cu₂O particles were obtained instead of Cu particles. The resultant copper particles were confirmed by EDX and XRD to be pure Cu, with face-centred cubic (fcc) structures.     

L-抗坏血酸-2-聚磷酸酯的合成

研究了L 抗坏血酸与磷酸化试剂在水介质中制备L 抗坏血酸 2 一聚磷酸酯和L 抗坏血酸 2 三聚磷酸酯 ,当n(L 抗坏血酸 )∶n(三偏磷酸钠 )∶n(催化剂 ) =1 .0 0 0∶1 2 0 0∶0 1 50、溶液pH值为 8时 ,L 抗坏血酸 2 三聚磷酸酯的收率为 71 34% ,Vc效价为 32 1 0 %。作为饲料添加剂使用 ,可同时给动物补充钙和磷。