Electrochemical Nucleation of Au on n-Type Semiconductor Silicon Electrode Surface

在成功实现半导体硅表面电沉积致密金膜的柠檬酸盐镀金实际应用体系中,运用循环伏安和电位阶跃法研究了Au在n型SI(111)电极表面的电沉积过程和成核机理.结果表明,在该体系中,Au在SI表面呈现不可逆电极过程,成核过电位达到250 M V;根据COTTrEll方程求得扩散系数d=(1.81±0.14)x10–4 CM2 S–1;运用SCHArIfkEr-HIllS(SH)理论模型对比分析拟合实验结果,表明Au在n型SI表面遵循扩散控制下的三维连续成核机理;通过扫描电子显微镜观察Au初期成核、生长形貌,进一步证实了Au的三维连续成核机制,并讨论了阶跃电位和阶跃时间对Au核形貌和密度的影响.Cyclic voltammetry and chronoamperometry have been used to investigate the mechanism of gold electrodeposition on the n-Si(111) electrode surface from a citrate bath, which had successfully applied to directly electroplate a dense gold film on the silicon surface.The results show that Au electrodeposition on the n-type silicon surface is an irreversible process, and the nucleation overpotential reaches 250 m V.According to Cottrell equation, the diffusion coefficient(D) is calculated to be(1.81 ± 0.14) × 10-4 cm2 s-1.The Scharifker-Hills(SH) model was used to analyze the experimental data.Agreement between the fitting curves and the theoretical curves confirms that the nucleation process of Au electrodeposition on the n-type silicon surface follows the progressive nucleation mechanism with three-dimensional growth under diffusion control.To further confirm the progressive nucleation mechanism, scanning electron microscopy(SEM) was used to observe the nucleation and growth of Au deposits at the initial stage of electrodeposition.The SEM results show that the morphology and density of the Au deposits are affected by the electrochemical deposition potential and time.国家重大科学仪器设备开发专项(2011YQ03012406); 国家自然科学基金界面电化学创新群体(21321062)及国家自然科学基金(21373172)资助项目~

人乳头瘤病毒假病毒制备方法的优化

人乳头瘤病毒假病毒可广泛应用于中和抗体鉴定和疫苗免疫性评估等研究.本研究对多质粒共转染293FT细胞生产HPV假病毒的方法进行了深入优化,结果显示不同的HPV结构蛋白表达质粒转染比例对于假病毒生产效率有显著的影响,HPV主要结构蛋白L1的表达水平是影响生产效率的主要因素,L2表达质粒的用量过高或过低均不利于假病毒的生产,而报告质粒的用量对假病毒生产效率的影响相对较小.综合比较显示,在该体系中L1和L2表达质粒和报告质粒以合适比例(如1∶1/10∶1/2)进行共转染可获得更为理想的生产效率.本研究同时也在293FT细胞中对磷酸钙转染方法进行了优化,通过磷酸钙与质粒用量的交叉配比试验获得了较优的转染条件.通过优化,建立了更为高效的HPV假病毒大量制备方法,在HPV16、HPV18、HPV6、HPV11假病毒生产中的应用结果显示较原方法可显著提高生产效率.本研究为HPV假病毒中和实验的规模化应用提供了有利条件

缝纫机针杆表面沉积含过渡层DLC薄膜及性能的研究

本文以C2H2为碳源，Ar气为辅助气体，采用新型离子束源和磁控溅射源的混合技术在缝纫机针杆上成功制备了具有不同过渡层的类金刚石薄膜，并表征了薄膜的表面形貌，测量了其硬度、结合力、摩擦系数，划痕法的结果表明，增加过渡层后薄膜的结合状况得到明显改善，DLC膜的硬度也得到了提高，摩擦磨损实验结果可以看出样品的摩擦系数均在0.1以下，可以极大地改善不锈钢针杆的摩擦性能

Effects of spring rainfall distribution on soil respiration in a coastal wetland of the Yellow River Delta

Changes of rainfall seasonal pattern would affect carbon cycling in coastal wetlands by influencing the transport of water and salt in soils. Seed germination and plant growth in coastal wetlands are sensitive to rainfall availability in spring,but the underlying mechanism of spring rainfall distribution on soil respiration is still unclear. An in-situ spring rainfall control field experiment with five treatments (+73%,+56%,control,-56% and -73% in spring,but the annual total rainfall remained the same) were set up to explore the effects of spring rainfall distribution on soil respiration of a coastal wetland on the Yellow River Delta. Soil water content in spring significantly increased with the increasing rainfall partitioning in spring,while that in autumn significantly decreased. The seasonal variation of soil salinity was opposite to soil moisture, and soil salinity showed strongest fluctuations in spring compared with other seasons. The total belowground biomass and the proportion of belowground biomass in deep soil layer increased with the increasing spring rainfall partitioning,while the proportion of belowground biomass in shallow soil layer showed an opposite pattern. Mean annual soil respiration rate was decreased with the decreasing spring rainfall partitioning,and was significantly different between +73% and -73% treatments (P<0.05). Soil respiration rate differed among different seasons. Soil respiration rate in spring and summer increased with the increasing rainfall partitioning in spring,but decreased in autumn and winter. However,the positive effect of increased spring rainfall partitioning on soil respiration in spring and summer was much greater than the negative effect in autumn and winter. Mean annual soil respiration was closely related to soil moisture and soil salinity in spring,and remarkably affected by the proportion of belowground biomass of different soil layers and total belowground biomass

透视“大宇神话”

一、大宇集团的基本情况韩国第二大企业集团大宇集团1999年11月1日向新闻界正式宣布,该集团董事长金宇中以及14名下属公司的总经理决定辞职,以表示"对大宇的债务危机负责,并为推行结构调整创造条件"。韩国媒体认为,这意味着"大宇集团

三次采油用烷基苯磺酸盐弱碱体系的研究

通过对抚顺洗涤剂化学厂的烷基苯进行切割处理，合成了平均烷基碳链长度为C14、C17、C20、C23，的烷基苯磺酸钠。经过复配，在弱碱（Na2CO3）条件下研究了大庆三厂油／水的界面张力、稳定性和驱油效率。结果表明：以平均烷基碳链长度在17左右的烷基苯磺酸盐为主剂进行复配后，得到的样品可以在弱碱条件下，使大庆三厂的油／水界面张力在较宽的碱质量分数w（Na2CO3）=0．2％～0．8％及表面活性剂质量分数w（表面活性剂）：0．025％-0．2％条件下维持在超低水平（10^-3mN／m），并能保持长期稳定，驱油效率比水驱提高20％以上

三次采油用烷基苯磺酸盐弱碱体系的研究

通过对抚顺洗涤剂化学厂的烷基苯进行切割处理，合成了平均烷基碳链长度为C14、C17、C20、C23，的烷基苯磺酸钠。经过复配，在弱碱（Na2CO3）条件下研究了大庆三厂油／水的界面张力、稳定性和驱油效率。结果表明：以平均烷基碳链长度在17左右的烷基苯磺酸盐为主剂进行复配后，得到的样品可以在弱碱条件下，使大庆三厂的油／水界面张力在较宽的碱质量分数w（Na2CO3）=0．2％～0．8％及表面活性剂质量分数w（表面活性剂）：0．025％-0．2％条件下维持在超低水平（10^-3mN／m），并能保持长期稳定，驱油效率比水驱提高20％以上

三次采油用烷基苯磺酸盐弱碱体系的研究

通过对抚顺洗涤剂化学厂的烷基苯进行切割处理，合成了平均烷基碳链长度为C14、C17、C20、C23，的烷基苯磺酸钠。经过复配，在弱碱（Na2CO3）条件下研究了大庆三厂油／水的界面张力、稳定性和驱油效率。结果表明：以平均烷基碳链长度在17左右的烷基苯磺酸盐为主剂进行复配后，得到的样品可以在弱碱条件下，使大庆三厂的油／水界面张力在较宽的碱质量分数w（Na2CO3）=0．2％～0．8％及表面活性剂质量分数w（表面活性剂）：0．025％-0．2％条件下维持在超低水平（10^-3mN／m），并能保持长期稳定，驱油效率比水驱提高20％以上