Electrochemical Study on Electroless Nickel Plating Using Sodium Borohydride as the Reductant

Corresponding author. Email: [email protected]; Tel: +86-592-2180738.[中文文摘]采用线性电位扫描伏安法研究了以硼氢化钠为还原剂的化学镀镍体系,考查了镀液组成及工艺条件对化学镀镍硼阴、阳极过程的影响,结果表明:乙酸镍和硼氢化钠含量的提高分别促进了Ni2+的还原反应和BH-4的氧化反应;乙二胺、氢氧化钠以及添加剂硫脲、糖精钠对阴、阳极反应均有不同程度的抑制作用,同时添加剂中的硫元素加速了镍的氧化;升高温度有利于阴、阳极反应的进行.[英文文摘]We studied electroless Ni-B plating with sodium borohydride as the reductant by linear sweep voltammetry.The effects of bath solution composition and operating conditions on the cathodic reduction and anodic oxidation were studied.Increases in the concentrations of nickel acetate and sodium borohydride accelerated the reduction of Ni2+ and the oxidation of BH4,respectively.Ethylenediamine,sodium hydroxide,thiourea and saccharin sodium inhibited both the cathodic and anodic reactions to varying degrees.Additionally, sulfur in the additives promoted the dissolution of nickel. High temperature was beneficial to both the cathodic reduction and anodic oxidation.国家自然科学基金(20573086)资助项

The Influence of Economic Growth to Environmental Pollution and Regional Heterogeneity——Evidence from Provincial Dynamic Panel Data Model

利用1992~2011年我国省际面板数据,通过主成分分析法构造环境污染综合指标,进而建立面板数据模型,实证分析了经济增长对环境污染的影响及区域性差异,并讨论了环境污染治理投资、技术进步、人口、储蓄率、产业结构和贸易开放度等因素对环境污染的影响。实证结果发现,从全国范围来看,经济增长对环境污染的影响符合环境库兹涅茨曲线假说,且目前已处于倒u型曲线的下降部分;东部地区和中部地区同样存在倒u型关系并处于其下降部分,西部地区呈现出n型关系并处于右侧上升部分。同时,不同控制变量对环境污染的影响也具有不同特点。This paper empirically investigates the influence of economic growth to environmental pollution and regional heterogeneity.We also discuss the influence of other factors to environmental pollution, including abatement investment, technology, population, saving rate, industrial structure and trade openness.Empirical results suggest that the effect of economic growth to environmental pollution copes with the Environmental Kuznets Curve from the perspective of the whole nation, laying on the right downward part of the inverted-U curve.From regional perspective, there also exists inverted-U shaped curve in the eastern and middle regions while in the western region the relationship appears to be N shaped.Meanwhile, the influence of other factors displays distinct characteristics

Electrochemical Study on Electroless Nickel Plating Using Sodium Borohydride as the Reductant

We studied electroless Ni-B plating with sodium borohydride as the reductant by linear sweep voltammetry. The effects of bath solution composition and operating conditions on the cathodic reduction and anodic oxidation were studied. Increases in the concentrations of nickel acetate and sodium borohydride accelerated the reduction of Ni(2+) and the oxidation of BH(4)(-), respectively. Ethylenediamine, sodium hydroxide, thiourea and saccharin sodium inhibited both the cathodic and anodic reactions to varying degrees. Additionally, sulfur in the additives promoted the dissolution of nickel. High temperature was beneficial to both the cathodic reduction and anodic oxidation.National Natural Science Foundation of China[20573086

ST段抬高型急性心肌梗死院前溶栓治疗中国专家共识

急性心肌梗死仍然严重威胁我国人民健康,在我国广大城乡地区,形势更为严峻[1,2]。及时救治急性心肌梗死患者,降低死亡率和保护心脏功能刻不容缓。鉴于我国的实际情况,院前溶栓治疗在大城市以外的城乡地区具有重要意义。为此,中国医师协会胸痛专业委员会及中国医学救援协会心血管急救分会专门组织有关专家制订了本共识,旨在帮助院前医疗急救人员对急性心肌梗死患者选择最佳

微藻中棕榈油酸的研究进展

棕榈油酸是一种ω-7单不饱和脂肪酸,它具有重要的营养和医药保健价值,同时也是制备生物柴油和1-辛烯的优质原料。棕榈油酸普遍存在油料作物中,但是含量较低,而含量较高的野生植物又存在资源少问题,因此利用富含棕榈油酸且适合大规模培养的微藻是解决棕榈油酸来源的一条新型途径。本文重点介绍了微藻中棕榈油酸来源的优势、棕榈油酸的生理功能、微藻中棕榈油酸的合成途径及分离纯化方法,并且展望了棕榈油酸进一步的研究方向

影响集成电感性能的关键因素

片上集成电感是单片集成射频电路、微波电路及光电集成电路中不可缺少的重要元件。高Q值的片上集成电感是IC工作者追求的目标。衬底损耗和金属损耗一直被认为是限制集成电感品质的主要因素,文中实例为证，在尽量消除衬底损耗和减小金属损耗条件下。得出它们并不是片上集成电感的决定性限制因素。本文从电感的定义出发，得出电感螺旋线之间磁通量的相互抵消是集成电感不能获得高Q值的决定因素。并通过螺旋电感的模拟计算和结合已有的实验，对此论点进行了论证

CORROSION ELECTROCHEMICAL BEHAVIOR of Ni-B COATING ON MAGNESIUM ALLOY AZ91D PREPARED BY DIRECTLY ELECTROLESS PLATING

研究了镁合金表面化学镀nI-b合金的电化学行为,采用电化学动电位扫描极化曲线和交流阻抗研究了nI-b镀层的腐蚀电化学行为,结果表明,nI-b镀层在3.5%nACl溶液中具有优良的耐蚀性能.所得nI-b镀层的自腐蚀电位在-400MV左右,相对于基体-1460MV提高了1000MV,自腐蚀电流密度小于0.7μA/CM2,相对于基体28.5μA/CM2降低了近两个数量级,说明nI-b镀层能够有效地提高Az91d镁合金的耐腐蚀性能,使Az91d镁合金在3.5%nACl溶液腐蚀介质中的腐蚀速度明显降低.电化学交流阻抗测试结果符合极化曲线的测量结果,化学镀nI-b镀层后的Az91d镁合金在3.5%nACl溶液中的阻抗值相对于基体提高两个数量级,表现为自腐蚀电流降低,阻抗值相应提高.Corrosion electrochemical behavior of a directly electroless-plated Ni-B coating on magnesium alloy was investigated by means of potentiodynamic and electrochemical impendence spectroscopy(EIS).The results indicated that the corrosion resistance of the coating was excellent in 3.5% sodium chloride solution.The corrosion potential was around-400 mV and the current density was less than 0.5 μA/cm2,which exhibits that the coating can significantly enhance the corrosion resistance of the substrate

次氯酸钠处理多孔PAN纤维的结构与吸附性能研究

以聚丙烯腈/聚乙烯吡咯烷酮/二甲基亚砜(PAN/PVP/DMSO)三元体系为纺丝液,以DMSO/H_2O为凝固浴,在凝固浴温度为60℃下,通过湿法纺丝制备了具有介孔结构的多孔PAN/PVP纤维;用次氯酸钠(NaClO)对多孔PAN/PVP纤维进行处理,制得了NaClO@PAN/PVP纤维,采用场发射扫描电镜、元素分析仪和氮气气体吸附仪对处理前后纤维的表面形貌、元素组成、比表面积和孔径进行了表征,研究了凝固浴浓度和温度对PAN/PVP纤维和NaClO@PAN/PVP纤维的PVP含量及比表面积和孔径的影响。结果表明:经NaClO处理后,NaClO@PAN/PVP纤维中氧含量减少,氮含量增多,PVP含量减少,纤维表面变得光滑,平均孔径减小,孔数增多,比表面积增大;随着凝固浴DMSO浓度增大或温度升高,PAN/PVP纤维,NaClO@PAN/PVP纤维中的PVP含量降低,但其比表面积随凝固浴浓度的增大而减小,随凝固浴温度的升高而先升高后减小;在凝固浴DMSO质量分数为0,温度为60℃的条件下制得的PAN纤维、PAN/PVP纤维、NaClO@PAN/PVP纤维的比表面积分别为38,96,108 m~2/g,平均孔径分别为22.7,20.4,19.0 nm;PAN/PVP纤维、NaClO@PAN/PVP纤维的最可几孔径分布在40 nm左右,属于介孔结构

高频大功率SiGe／SiHBT的设计

详细地阐述了高频大功率SiGe／Si异质结双极晶体管（HBT）设计中的一些主要问题，主要包括器件的纵向设计中发射区、基区以及收集区中掺杂浓度、形貌分布、层厚的选择以及横向布局设计中的条宽、间隔的选择等。并对这些主要参数的选择给出了一些实用的建议