Current Efficiency and Deposit Microhardness of Nickel-Tungsten Alloy Electrodeposition

通过调节镀液中不同的 nI/ W 比例、温度和沉积电流密度，研究在焦磷酸盐体系中镍钨合金电沉积的电流效率、沉积层组成和显微硬度。实验结果表明：合金共沉积的电流效率不高。为了尽量提高合金的沉积电流效率，主要途径宜增大镀液中硫酸镍和钨酸钠的浓度；提高合金沉积电流密度，降低镀液中［ nI］/［ W］ 比例，则镀层中的钨含量增大；合金沉积层的显微硬度随镀层中的 W 含量提高而增大。Current efficiency, deposit composition and microhardness of nickel-tungsten alloy electrodeposition in pyrophosphorus bath were studied by adjusting Ni/W ratio in plating solution, temperature and deposition current density.The results showed that the current efficiency of the alloy codeposition was not high.For the purpose to raise current efficiency as far as possible the suitable solution was to increase the concentration of nickel sulfate and sodium tungstate in the bath, Tungsten content in the alloy deposit can be increased by raising electrodeposition current density and decreasing [Ni]/[W] ratio in the plating solution.The microhardness of the alloy deposit increases with the raise of tungsten content in the deposit.国家自然科学基

基于差分统计方法的舌象纹理特征的分析与识别

为探讨舌诊客观化的方法,依据中医纹理判断的特点,针对舌象纹理特征分析,应用灰度差分统计方法,从对比度(CON) 、角度方向二阶矩(ASM) 、熵(ENT) 、平均值(MEAN) 四个参数,进行舌象纹理的量化和定义分类,并尝试将舌质老嫩的判别方法应用与临床舌质的判别,总体识别率为74 %。上海市教育青年基金资助项目(02CK22

钼酸盐柠檬酸盐络合物及有机酸对棕色固氮菌生长的影响

将经过0.9%NaCl溶液处理8h的棕色固氮菌(AzotobactervinelandiiOP)作为菌种分别接入Burk′s培养基和用不同有机酸替代柠檬酸三钠或用不同等摩尔的钼络合物替代钼酸钠的各种改良的Burk′s培养基中,分别测定菌体生长曲线和固氮活性.结果发现,与Burk′s培养基相比,以高柠檬酸、苹果酸、马来酸替代柠檬酸三钠或以K6[Mo2O5(cit)2]·5H2O、K4[Mo2O5(Hcit)2]·4H2O和Na2[MoO2(Hcit)]·3H2O替代柠檬酸三钠和钼酸钠的培养基能促进菌体的生长;以乙醇酸替代柠檬酸三钠的培养基则会抑制固氮菌的生长;各种培养条件下菌体细胞的C2H2还原活性表现了类似的规律.讨论了固氮酶活性中心FeMoco在装配过程中钼的可能运输方式和装配机理

正常及异常牙周膜在不同载荷作用下应力分布的研究——应用三维有限元计算

本文应用三维有限元研究了正常及异常牙周膜在不同载荷作用下的应力分布,得到牙周膜的应力分布规律。(1)通过牙体生理中心(几何中心)的力,应力分布最均匀,以压应力为主,对牙周膜有利;(2)其它类型的力均可使牙周膜受力不均匀,以与牙长轴呈90°角的侧向力危害严重,可同时产生较大的压应力和拉应力;(3)牙周膜内应力值随牙槽骨高度降低而增高,尤以根尖区和牙槽嵴顶区变化剧烈;(4)外力方向、作用点位置对异常牙周膜应力值有明显影响

Electrocrystallization Mechanism、 Structure and Microhardness of Ni-W-P Alloy Eletrodeposits

应用循环伏安、恒电位阶跃和 X射线衍射（ XRD）等方法研究了 Ni-W-P合金电沉积特点和镀层结构与显微硬度 .结果表明，在以柠檬酸铵为配体的溶液中， Ni-W-P合金沉积层较 Ni-W合金有较低的电化学活性 .根据电位阶跃的 i～ t曲线分析表明，在玻碳电极上 Ni-W-P合金电结晶过程遵从扩散控制瞬时成核三维成长模式进行，随着过电位的增加，电极表面上晶核数增多 . XRD试验结果表明， Ni-W-P合金镀层呈现明显的非晶态特征 .所获得的 Ni-W-P合金电沉积层的显微硬度在 450 kg· mm－ 2左右 .The electrodeposition characteristics,structure and microhardness of Ni-W-P alloy have been studied by the methods of cyclic voltammetry, potentiostatic step and X-ray diffraction(XRD). The results showed that Ni-W-P alloy electrodeposit obtained from the solution containing ammonium citrate as complexing agent presented lower electrochemical activity compared with Ni-W alloy electrodeposit. Based upon the i～ t curves of potentiostatic step, it was revealed that electrocrystallization of Ni-W-P alloy on glassy carbon electrode followed the mechanism of instantaneous nucleation and three dimensional growth with diffusion controll.The crystal nucleus number on the surface of electrode was raised by the increase of overpotential.XRD experimental results showed that the Ni-W-P alloy electrodeposits obtained were obviously of the amorphous structure, and the microhardness of the alloy was about 450 kg/mm2 at the stated plating solution and conditions.国家自然科学基金!(29773039

牙根尖区应力分布的三维有限元计算

本文应用三维有限元分析了牙周膜的应力分布。重点讨论了根尖区应力分析结果及其对临床解释病因及对诊断的意义。本文将右下第一恒磨牙有限元模型划分为210个单元及1612个节点(用20节点等参元),分析了11种典型受力状况,得出以下结论:(1)在(牙合)面上通过牙周膜几何中心的各种外力在根尖区产生的应力分布均匀,且应力值较小,无拉应力产生;(2)在计算的11种典型载荷中有三种载荷应力分布危害性最大

Effects of Nicotinic Acid on Copper Electrodeposition in Acid Sulphate

对溶液A:0.8mol·L-1硫酸铜,0.6mol·L-1硫酸,5.0×10-5mol·L-1氯离子,1.0×10-4mol·L-1聚乙二醇的溶液,溶液B:在溶液A中加入2.0×10-2mol·L-1烟酸,pH为0.5,运用循环伏安和计时安培法研究玻碳电极上铜的电沉积行为.结果表明,铜的电沉积过程经历了晶核形成过程,其电结晶按瞬时成核和三维生长方式进行.烟酸的加入对铜的电沉积具有阻化作用,但不改变铜的电结晶机理.沉积层的X射线衍射表明Cu为面心立方结构,在烟酸存在下沉积层出现(220)高择优取向,这可能是烟酸在Cu(220)晶面上发生强烈吸附作用的结果.Initial stages of electrodeposition of copper on glassy carbon electrode from 0.8 mol·L-1 copper sulphate electrolyte solution containing 2.0×10-2 mol·L-1 nicotinic acid are studied using cyclic voltammetry and chronoamperometry.The results show that nicotinic acid (NA) produces an inhibition of copper deposition,probably related to the adsorption of nicotinic acid.The initial deposition kinetics corresponds to a model including instantaneous nucleation and diffusion controlled growth.The X ray diffraction results indicate that copper deposits exhibit face centered cubic structure and (220) highly preferred orientation.Nicotinic acid produces uniform and smooth surfaces of copper deposit.国家自然科学基金(20073037)和厦门大学科学研究基金资助项

Effect of Electrolyte Composition on Electrodeposition of Ni-W Alloy

采用电化学、分光光度、X 射线衍射和金相显微技术等方法研究nI-W 合金电沉积电流效率、沉积层的组成、结构和表面形态。结果表明，随着镀液中钨酸钠浓度提高，合金沉积层中的W 含量变化不大，沉积电流效率提高；形成置换固溶体的合金沉积层X 射线衍射（Xrd）峰强度降低，趋于矮胖，2θ向低角度偏移；引起（111）晶面间距、晶胞参数和晶格畸变的增大，而显微晶粒尺寸减小；合金沉积层的电结晶生长形态逐渐呈均匀排列的团粒状。The effects of sodium tungstate contents on the current efficiency, composition, structure and morphology of Ni\|W alloy electrodeposit obtained in citrate bath were studied by electrochemistry, spectrophotometry, X\|ray diffraction and metallographic methods.It was shown that by the increase of sodium tungstate content in electrolyte, W content in the electrodeposit tended to a slightly change, current efficiency to raise and XRD peak intensity to decrease.The morphology of the deposit assumed even arranged granular structure.国家自然科学基金!资助项目（项目批准号：29773039

Structure and Property of Ni-W-B Alloy Electrodeposits Before and After Heat Treatment

采用电化学技术、 XPS、 DSC、 XRD等方法研究 Ni-W-B合金电沉积及热处理前后合金镀层的结构和显微硬度 .结果表明，在 Ni-W-B合金电沉积过程中伴随着化学沉积镍等过程以及 Na2B4O7在镀层中的夹杂； Ni-W和 Ni-W-B合金电沉积层分别表现为纳米晶结构和非晶态结构；热处理过程中合金电沉积层发生晶粒粗化过程以及 Ni-W-B合金镀层发生新相形成过程，产生 Ni4W和镍硼化物如 Ni2B、 Ni3B等沉淀物； 400℃热处理 2 h后 Ni-W合金镀层有最大的显微硬度达 919.8 kg· mm－ 2，而在 500℃下 Ni-W-B合金有最大的硬度达 1132.2 kg· mm－ 2.The structure and microhardness of Ni-W-B alloy were studied by means of electrochemical techniques, XPS, DSC and XRD before and after heat treatment. The results showed that the process of Ni-W-B alloy electrodeposition was accompanied by the chemical deposition of Ni and adulteration of Na2B4O7 in the deposit. Ni-W alloy presented in nanocrystalline structure and Ni-W-B in amorphous structure were both coarsened in grain size and led to the evolution of Ni4W, and precipitation of Ni－ B compound such as Ni2B, Ni3B in Ni-W-B alloy after heat treatment. The maximum microhardness could be observed for Ni-W alloy at the value of 919.8 kg· mm－ 2 after heat treatment for 2 hours at temperature of 400℃ and Ni-W-B alloy at 1132.2 kg· mm－ 2 (500℃ , 2 hrs).国家自然科学基金资助项目! (29773039) &

Effect of Current Density on the Composition, Structure and Morphology of Ni W Alloy Electrodeposit

采用分光光度法、X射线衍射和金相显微镜等方法研究在焦磷酸盐体系中，电流密度影响下所获得的nI-W合金电沉积层的组成、结构和表面形态.结果表明，随着电流密度的提高，合金沉积层中的W含量增大；形成置换固溶体的合金沉积层晶格参数涨大、晶格畸变度增大、而显微晶粒尺寸减小；合金沉积层的电结晶生长形态均呈现整齐的团粒状生长特征.讨论了上述实验结果.The effect of current density on the composition, structure and morphology of Ni W alloy electrodeposit obtained in pyrophosphate bath were studied by the methods of spectrophotometry, X ray diffraction and metallurgical microscope.The results show that, by the increment of the cathodic current density,the alloy electrodeposit was formed in displacemental solid solution, and that, with W content raised,lattice parameter expanded,and lattice distortion increased, whereas grain size decreased.All the morphologies of the deposits were presented in neat granular structure in the growth of electrocrystallization.The results were discussed.国家自然科学基