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Search Results: 1 - 10 of 31510 matches for " TIAN Zhong-qun "
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壳层厚度可调控的Ag@Pd@Pt纳米粒子的合成和甲酸电催化研究
Syntheses of Ag@Pd@Pt Nanoparticles with Tunable Shell Thickness for Electrochemical Oxidation of Formic Acid

林晓东,陈杜宏,田中群
LIN Xiao-dong
, CHEN Du-hong, TIAN Zhong-qun

- , 2016, DOI: 10.13208/j.electrochem.160569
Abstract: 摘要 在本课题组研究55 nm Au@Pd@Pt对甲酸电催化效果基础上,我们采用Ag取代Au制备55 nm Ag@Pd@Pt纳米粒子以降低催化剂的成本,并对甲酸的电催化行为进行研究. 研究表明:少量Pt的存在可大幅度提高催化剂的活性,当Pt的覆盖度为0.5 单原子层(ML)时,起始氧化电位最为靠前,氧化峰电流最大,这与Au@Pd@Pt纳米粒子对甲酸电催化行为类似. 与Au@Pd@Pt纳米粒子相比,其最佳起始氧化电位偏正0.05 V,但电催化活性并没有明显的降低. 通过改变催化剂比表面积研究甲酸的电催化行为,发现将9 nm Ag纳米粒子作为内核的9 nm Ag@Pd@Pt负载在活性炭中,在保持催化活性不变的情况下,碳载的催化剂价格可比55 nm Au@Pd@Pt纳米粒子降低220倍左右
水助催化氢分子在金纳米粒子上解离的理论研究
DFT Study of Water Assisted Hydrogen Dissociation on Gold Nanoparticles

陈家丽,张霞光,吴德印,田中群
CHEN Jia-li
, ZHANG Xia-guang, WU De-yin, TIAN Zhong-qun

- , 2018, DOI: 10.13208/j.electrochem.170918
Abstract: 摘要 金纳米粒子(GNPs)对氢分子(H2)的解离具有良好的催化活性. 本文研究了水分子对 GNPs 催化 H2 解离的影响. 对于H2在中性和带正电的金簇(Aunδ,n=3~5;δ = 0,1)上的反应,考虑当水簇((H2O)m,m = 1, 2, 3, 7)参与反应时 GNPs 催化H2的解离过程的热力学和动力学. 研究结果表明,水对 H2 在GNPs上的解离有助催化的作用,且水簇大小不同,水助催化 H2 在金簇上解离的机理也有所不同,其由氢氢键的均裂解离转化为氧化解离. 对两种机理所得的产物,作者计算了它们的 Raman 和 IR 光谱
表面增强拉曼光谱研究吸附电位对CO在Pt电极上氧化行为的影响
Effect of Adsorption Potential on CO Oxidation at Au@Pt Nanoparticles Electrodes, A Surface Enhanced Raman Spectroscopic Study

张普,卫怡,郑勇力,陈艳霞,田中群
ZHANG Pu
, WEI Yi, ZHENG Yong-li, CHEN Yan-xia, TIAN Zhong-qun

- , 2015, DOI: 10.13208/j.electrochem.150309
Abstract: 摘要 预吸附电势对CO在Pt上的氧化行为有重要影响. 在电势低于0.3 V(vs. RHE)下,预吸附的CO单层在Pt电极上0.4 V就开始氧化,并会在0.6 V左右出现1个较小的氧化峰,即所谓的“氧化前峰”,而在双电层电位区间饱和吸附的CO只有当电势正于0.6 V才氧
玻碳电极表面复合配位银电结晶机理研究
Complex Coordination Silver Electrocrystallization Mechanism on Glassy Carbon Electrode Surface

黄帅帅,刘诚,金磊,杨防祖,田中群,周绍民
HUANG Shuai-shuai
, LIU Cheng, JIN Lei, YANG Fang-zu, TIAN Zhong-qun, ZHOU Shao-min

- , 2018, DOI: 10.13208/j.electrochem.180105
Abstract: 摘要 以具有实际应用价值的复合配位体系无氰镀银电解液为研究对象, 运用循环伏安和电位阶跃等实验方法, 结合 Scharifker-Hill 经典理论模型分析, 成功获得了Ag在玻碳电极(GCE)表面电沉积的成核机理及成核动力学参数, 并分析了温度对成核方式及成核动力学参数的影响. 结果表明, 该体系下Ag在GCE表面的电沉积是由扩散控制的不可逆过程, 遵循三维瞬时成核生长机理. 随着阶跃电位从-750 mV 负移至-825 mV, 峰值还原电流Im逐渐增大, 达到峰值还原电流所需时间tm逐渐缩短; 扩散系数D变化不大, 基本稳定在(7.61±0.34)×10-5 cm2·s-1; 成核密度数N0则从3.26 ×105 cm-2提高至10.2×105 cm-2. 银沉积初期的形貌观察, 验证了其三维瞬时成核生长机理. 提高温度可以显著改善电解液中具备活性的银配位离子的扩散能力, 缩短成核时间, 提升成核密度数N0.
Cyclic voltammetry and potential step methods were successfully used to study the electrochemical crystallization mechanism of silver deposition on glassy carbon electrode (GCE) in the practical cyanide-free silver plating electrolyte containing composite complexing agents. Scharifker-Hill (SH) theory was used to fitting the experimental data. The results showed that the electrodeposition of silver is a diffusion controlled irreversible electrode process according to three-dimensional instantaneous nucleation mechanism. When the step potential shifted from -750 mV to -825 mV, the peak deposition current Im was increased, while the induced nucleation time tm shortened. The calculated kinetic parameters showed that the diffusion coefficient (D) was basically constant, ranged (7.31 ±0.34) ×10-5 cm2·s-1, and the active nucleation sites density (N0) increased from 3.26 ±105 cm-2 to 10.2±105 cm-2. The morphologies for the initial deposition of Ag verified the three-dimensional instantaneous nucleation mechanism. Increasing the temperature could significantly improve the diffusion ability of the active silver coordination ions in the electrolyte, which shortened the nucleation time and enhanced the active nucleation sites density N0
SPR银金电极上光电化学反应和EC-SERS理论研究
Theoretical Study of Photoelectrochemical Reactions and EC-SERS on SPR Metallic Electrodes of Silver and Gold

吴元菲,庞 然,张 檬,周剑章,任 斌,田中群,吴德印
Wu Yuan-fei
, Pang Ran, Zhang Meng, Zhou Jian-zhang, Ren Bin, Tian Zhong-qun, Wu De-yin

- , 2016, DOI: 10.13208/j.electrochem.160149
Abstract: 摘要 随着纳米科学的发展,人们再次关注到金属电极上的光电化学研究. 这主要得益于币族金属纳米结构具有强的表面等离激元共振(SPR)效应,它能有效地将光从远场光转化为近场光,汇聚光能到金属表面区域,可以在表面产生强的光电场效应,或产生较长寿命的热电子-空穴载流子效应,或是更长时间尺度的热效应. 因此,SPR效应不仅产生了表面增强拉曼散射(SERS)效应,用于表征吸附分子,而且可能诱发表面化学反应,为在电化学界面实现光与电协同调控化学反应提供新思路. 本文首先回顾了金属电极上光电流理论的发展,然后总结了本研究组近年来将量子化学计算用于光电化学反应和SERS光谱研究的工作,并以在银金纳米结构电极上水合质子还原和芳香胺氧化为例,比较了热电子和热空穴参与光电化学反应的特点,揭示了SPR参与光电化学反应的本质.
At present photoelectrochemistry has received much concern back to nanostructures of noble metals from semiconductor electrodes. This is due to the surface plasmon resonance (SPR) effect of metallic nanostructures, which can effectively convert the far-field light to the near-field light and concentrate the photonic energy to the local surface area with high energy density. Thus, the different enhancement mechanisms, such as the local optical field enhancement, the formation of light generated hot carriers (hot electron-hole pairs), or the photothermal effect, have been proposed in literatures. On the basis of the SPR enhancement effect, the surface-enhanced Raman spectroscopy (SERS) can be used to characterize the surface species but also induce surface chemical reactions. This provides a new idea to study the synergic effect of light and electricity in electrochemical interfaces. The article first reviewed a brief history of photoelectrochemistry, and then summarized our work on the light splitting water to hydrogen molecules, the photo-driven surface catalytic coupling reactions of the p-aminothiophenol oxidation and the p-nitrothiophenol reduction in electrochemical interfaces. Finally, we presented a simple prospective on the relationship of the SPR and the hot electron-hole pairs to plasmon-enhanced photoelectrochemical reactions
硫酸盐体系三价铬沉积机理及镀层表征
Deposition Mechanism and Coating Characterization for the Trivalent Chromium Electrodeposition in Sulphate Electrolyte

闫慧,黄帅帅,杨防祖,田中群,周绍民
YAN Hui
,HUANG Shuai-shuai,YANG Fang-zu,TIAN Zhong-qun, ZHOU Shao-min

- , 2018, DOI: 10.13208/j.electrochem.170441
Abstract: 摘要 在新研发的硫酸盐三价铬镀厚铬的镀液体系中, 运用线性扫描伏安法(LSV)和循环伏安法(CV)对三价铬在铜电极表面的电沉积过程进行研究, 并运用X射线荧光测厚仪、扫描电子显微镜(SEM)、X射线能量色散谱(EDS)、X射线衍射仪(XRD)、显微硬度计和Tafel曲线表征铬镀层厚度、形貌、组成、结构、显微硬度及在3.5wt% NaCl溶液中的耐蚀性. 结果表明, 在该体系中三价铬的沉积过程分两步进行(Cr3+ + e → Cr2+ , Cr2+ + 2e → Cr), 第一步得到1个电子, 受电化学过程和扩散过程共同控制, 第二步得到2个电子, 为扩散控制下的不可逆过程; 该镀层为瘤状纳米晶结构, 镀层中含有少量的铁元素(1.10 wt%), 显微硬度达到789.2 Hv, 镀层在3.5wt% NaCl溶液中的腐蚀电位(Ecorr)为-0.29 V, 腐蚀电流密度(jcorr)为9.26×10-5 A·dm-2.
Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were used to study the electrodeposition mechanism of trivalent chromium on a copper electrode in the novel sulphate electrolyte for thick trivalent chromium plating. The thickness, morphology, composition, microhardness, and structure, as well as the corrosion resistance in 3.5wt% NaCl solution of the trivalent chromium coatings were investigated by X-ray fluorescence gage, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), microhardness tester, X-ray diffraction (XRD) and Tafel curve measurements. The results showed that the electrodeposition of trivalent chromium involved two consecutive one electron reduction steps. The first step, Cr3+ + e → Cr2+,is controlled by the electrochemical reduction and diffusion processes, and the second step, Cr2+ + 2e → Cr, is an irreversible process under the diffusion control. The trivalent chromium coating exhibited nodular nanocrystalline structure and contained a small amount of iron (1.10wt%). The microhardness of the coating reached to 789.2 Hv. The corrosion potential (Ecorr) and corrosion current density (jcorr) of the coating in 3.5wt% NaCl solution were determined to be -0.29 V and 9.26×10-5 A·dm-2, respectively
玻碳电极表面因瓦合金的电化学成核机理
Electrochemical Nucleation of Invar Alloy on Glassy Carbon Electrode

黄先杰,闫慧,黄帅帅,杨防祖,田中群,周绍民
HUANG Xian-jie
, YAN Hui, HUANG Shuai-shuai, YANG Fang-zu, TIAN Zhong-qun, ZHOU Shao-min

- , 2017, DOI: 10.13208/j.electrochem.160318
Abstract: 摘要 在弱酸性因瓦合金(含镍质量分数为32~36 % 的镍铁合金)镀液中, 以线性扫描伏安法、循环伏安法和恒电位阶跃法对因瓦合金在玻碳电极表面的电沉积过程及其成核机理进行研究. 结果表明, 在该体系下, 因瓦合金在玻碳电极表面的电结晶属于扩散控制下的不可逆电极过程. 运用Scharifker-Hills理论模型(SH)拟合实验数据表明, 因瓦合金在玻碳电极表面的共沉积更加符合三维瞬时成核的成核规律. 运用Heerman-Tarallo理论模型(HT)分析得到因瓦合金在玻碳电极表面的成核生长的动力学参数, 当阶跃电位从-1.11 V变化至-1.17 V (vs SCE), 成核密度数(N0)由0.72×105 cm-2提高至1.91×105 cm-2, 成核速率常数(A)从 40.35 s-1增至 194.38 s-1, 扩散系数(D)为(7.67±0.15)×10-5 cm2?s-1, 变化不大.
Abstract: The linear sweep voltammetry, cyclic voltammetry and potential step methods were used to study the electrodeposition mechanism of Invar nickel-iron alloy (the mass fraction of nickel was 32~36%) on glassy carbon electrode surface in the weak acidic bath. The results demonstrate that the electrodeposition is was a diffusion controlled irreversible electrode process in this system. The Scharifker-Hill (SH) theory theoritic model (SH) were was used employed to fitting the experimental data and the result shows that the codeposition of Invar alloy on glassy carbon electrode surface conformed to the diffusion controlled three-dimensional instantaneous nucleation mechanism. The kinetic parameters were obtained by the Heerman-Tarallo (HT) theory theoretic model (HT). When the step potential shifted from -1.11 V to -1.17 V, the active nucleation sites density (N0) increased from 0.72×105 cm-2 to 1.91 ×105 cm-2. The nucleation rate constant (A) raised from 40.35 s-1 to 194.38 s-1 and the diffusion coefficient (D) was(7.67±0.15)×10-5 cm2?s-1, remaining basically constant
Activation of macrophage nuclear factor-κB and induction of inducible nitric oxide synthase by LPS
Ying-Hua Li, Zhong-Qun Yan, Annelie Brauner, Kjell Tullus
Respiratory Research , 2002, DOI: 10.1186/rr173
Abstract: Griess reaction was used to measure the nitrite level. Western blot and a semi-quantitative RT-PCR were performed to detect iNOS expression. Electrophoretic mobility shift assay (EMSA) was performed to analyze the activation of NF-κB.We found that LPS stimulated the rat alveolar macrophages to produce NO in a dose (≥10 ng/ml) and time dependent manner (p < 0.05). This effect was further enhanced by IFN-γ (≥10 IU/ml, p < 0.05), but was attenuated by budesonide (10-4–10-10 M) and dexamethasone (10-4–10-6 M) (p < 0.05). The mRNA and protein levels of iNOS were also induced in response to LPS and attenuated by steroids. LPS triggered NF-κB activation, a mechanism responsible for the iNOS expression.Our findings imply that Gram-negative bacterial infection and the inflammatory responses are important factors in the development of CLD. The down-regulatory effect of steroids on iNOS expression and NO production might explain the beneficial effect of steroids in neonates with CLD.Chronic lung disease (CLD) of prematurity, previously described as bronchopulmonary dysplasia by Northway and co-workers in 1967 [1], is a prolonged respiratory illness often needing long-time care such as prolonged ventilation, with up to one years oxygen dependency. The definition of CLD was later modified to encompass all forms of acute pulmonary injury during the first week of life, leading to a dependency on supplemental oxygen at a later stage (36 weeks of postconceptional age). The etiology of CLD is multifactorial and not fully understood. The development of CLD is characterized by an initial increase of inflammatory cells [2] and mediators [3,4]. Extensive release of proinflammatory cytokines, lipid mediators and other inflammatory mediators in neonates seems to play an important role in the maintenance of the inflammatory response in premature infants [2,5]. During later phases there is a dominance of lung fibrosis.Administration of steroids to infants with CLD, or those at high risk of d
Adaptive online retail Web site based on CA extended model
基于扩展元胞自动机的在线零售站点的自适应

WU Xiao-lan,WANG Zhong-qun,LIU Tao,WANG Yong,
吴小兰
,王忠群,刘涛,王勇

计算机应用 , 2006,
Abstract: In online retail, the conflict between the different interests of all customers to different commodities and the commodity classification structure of Web site will make most customers access overabundant Web pages. To solve the problem, building a Hidden Markov Model(HMM) to make the Web site adjust itself according to the users' visits to Web sites is one of the ways. Based on the initialization of hidden Markov Model, same results can be achieved by utilizing the theories of cellular automata extended model and less time was spent. This throws some light on the adaptation of Web site based on CA extended model.
A Mobile Agent Communication Algorithm
一种移动Agent通信算法

WANG Zhong-Qun,TAO Xian-Ping,FENG Xin-Yu,
王忠群
,陶先平,冯新宇

软件学报 , 2003,
Abstract: An algorithm based on communication algorithm in the Mogent system is presented in this paper. In this algorithm, address registration and multicasting are used by means of address-book so that it is more efficient, and suitable for many kinds of patterns of migration and communication and has a better solution to the troubles with mobile Agent communication.
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