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Search Results: 1 - 10 of 76160 matches for " YANG Fang-zu "
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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
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
Reversibility of Temperature-Induced Liquid Transition in Pb26Sn42Bi32 Melt: Experimental Evidence with Electrical Property

ZU Fang-Qiu,YU Jin,XU Wei,ZHANG Yan,YANG Hui-Zhen,

中国物理快报 , 2008,
Abstract: Exploring nature of liquid structures and properties is becoming more interesting in various fundamental and applied fields. With different resorts including the resistivity method, temperature-induced liquid--liquid structure transitions (TI-LLST) have been suggested and verified to occur in some liquidalloys, while the reversibility of TI-LLST has rarely been examined as yet. Unlike some other investigated liquid alloys, here we show that electrical resistivity of Pb26Sn42Bi32 melt exhibit an anomalous change in the first heating run and a reversible change in the following cooling and heating cycles. Taking account of the structural sensitivity of electrical resistivity, the abnormal patterns suggest two sorts of TI-LLST that are irreversible andreversible in the liquid ternary alloy, respectively. This interesting phenomenon together with other growing evidence imply that liquid structures and their change characteristics are multiform and complex.
The relationship between the intensity of summer southwest monsoon over northwest Pacific and the circulation patterns of the southern hemisphere
北半球夏季西北太平洋热带地区西南季风强弱变化与南半球环流型的关系

He Shi-xiu,Yang Zu-fang,
何诗秀
,杨祖芳

大气科学 , 1981,
Abstract: 本文分析了1978年夏季西北太平洋西南季风的强弱变化与南半球500mb环流形势的关系,发现当南半球出现经向环流型时,西南季风相应增强,反之,出现纬向环流型时,西南季风则减弱。 在南半球稳定的经向环流形势控制下,冷空气可以影响到低纬地带,高空长波槽后冷高压北侧的东南大风在其相对固定的通道上形成一股强而持久的越赤道气流,在北半球环流条件有利的情况下,这股越赤道气流可以在西北太平洋上转向成西南气流,导致该地区西南季风增强。由于南半球的长波槽容易在澳洲大陆东西两岸同时停滞加深,因此越赤道气流的路径则相对集中在这两
MiR-132 Suppresses the Migration and Invasion of Lung Cancer Cells via Targeting the EMT Regulator ZEB2
Jiacong You, Yang Li, Nianzhen Fang, Bin Liu, Lingling Zu, Rui Chang, Xuebing Li, Qinghua Zhou
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0091827
Abstract: MicroRNAs (miRNAs) are small, non-coding RNAs which can function as oncogenes or tumor suppressor genes in human cancers. Emerging evidence reveals that deregulation of miRNAs contributes to the human non-small cell lung cancer (NSCLC). In the present study, we demonstrated that the expression levels of miR-132 were dramatically decreased in examined NSCLC cell lines and clinical NSCLC tissue samples. Then, we found that introduction of miR-132 significantly suppressed the migration and invasion of lung cancer cells in vitro, suggesting that miR-132 may be a novel tumor suppressor. Further studies indicated that the EMT-related transcription factor ZEB2 was one direct target genes of miR-132, evidenced by the direct binding of miR-132 with the 3′ untranslated region (3′ UTR) of ZEB2. Further, miR-132 could decrease the expression of ZEB2 at the levels of mRNA and protein. Notably, the EMT marker E-cadherin or vimentin, a downstream of ZEB2, was also down-regulated or up-regulated upon miR-132 treatment. Additionally, over-expressing or silencing ZEB2 was able to elevate or inhibit the migration and invasion of lung cancer cells, parallel to the effect of miR-132 on the lung cancer cells. Meanwhile, knockdown of ZEB2 reversed the enhanced migration and invasion mediated by anti-miR-132. These results indicate that miR-132 suppresses the migration and invasion of NSCLC cells through targeting ZEB2 involving the EMT process. Thus, our finding provides new insight into the mechanism of NSCLC progression. Therapeutically, miR-132 may serve as a potential target in the treatment of human lung cancer.
Detecting Scale-Dependence of Bias from APM-BGC Galaxies
Li-Zhi Fang,Zu-Gang Deng,Xiao-Yang Xia
Physics , 1998, DOI: 10.1086/306220
Abstract: We present an investigation of the scale-dependence of bias described by the linear model: $(\delta \rho({\bf x})/\bar{\rho})_{g} = b (\delta \rho(x)/\bar{\rho})_{m}$, $b$ being the bias parameter, and $\rho({\bf x})_{g}$ and $\rho({\bf x})_{m}$ are the galaxy number density and mass density, respectively. Using a discrete wavelet decomposition, we show that the behavior of bias scale-dependence cannot be described by one parameter $b$. In the linear bias model the scale-dependence should be measured by the $j$-spectra of wavelet-coefficient-represented bias parameters $\tilde{b}^{(n)}_j$ and $b_j^{(n)}$, $n$ being positive integers. Because $\tilde{b}^{(n)}_j$ with different $n$ are independent from each other, a systematic analysis of the $j$-spectra of $\tilde{b}^{(n)}_j$ and $b_j^{(n)}$ is necessary. We performed a $j$-spectrum analysis for samples of elliptical and lenticular (EL), and spiral (SP) galaxies listed in the APM bright galaxy catalog. We found that, for statistics of two-point correlation functions or DWT power spectrum, the scale-independence holds within 1 $\sigma$. However, the bias scale-dependence becomes substantial when phase-sensitive statistics (e.g. $\tilde{b}^{(n)}_j$ with $n>2$ or $b_j^{(n)}$) are applied. These results indicate that the bias scale-dependence has the same origin as the non-Gaussianity of galaxy distributions. This is generally consistent with the explanation that the bias scale-dependence originated from non-linear and non-local relationship between galaxy formation and their environment.
北半球夏季西北太平洋热带地区西南季风强弱变化与南半球环流型的关系
何诗秀 He Shi-xiu,杨祖芳 Yang Zu-fang
大气科学 , 1981, DOI: 10.3878/j.issn.1006-9895.1981.01.06
Abstract: 本文分析了1978年夏季西北太平洋西南季风的强弱变化与南半球500mb环流形势的关系,发现当南半球出现经向环流型时,西南季风相应增强,反之,出现纬向环流型时,西南季风则减弱。在南半球稳定的经向环流形势控制下,冷空气可以影响到低纬地带,高空长波槽后冷高压北侧的东南大风在其相对固定的通道上形成一股强而持久的越赤道气流,在北半球环流条件有利的情况下,这股越赤道气流可以在西北太平洋上转向成西南气流,导致该地区西南季风增强。由于南半球的长波槽容易在澳洲大陆东西两岸同时停滞加深,因此越赤道气流的路径则相对集中在这两
Application of a Dynamic Identity Authentication Model Based on an Improved Keystroke Rhythm Algorithm  [PDF]
Wenchuan YANG, Fang FANG
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.28082
Abstract: Keystroke rhythm identification, which extracts biometric characteristics through keyboards without addi-tional expensive devices, is a kind of biometric identification technology. The paper proposes a dynamic identity authentication model based on the improved keystroke rhythm algorithm in Rick Joyce model and implement this model in a mobile phone system. The experimental results show that comparing with the original model, the false alarm rate (FAR) of the improved model decreases a lot in the mobile phone system, and its growth of imposter pass rate (IPR) is slower than the Rick Joyce model’s. The improved model is more suitable for small memory systems, and it has better performance in security and dynamic adaptation. This improved model has good application value.
Extraction kinetics of phenol with N, N-di (1-methyl-heptyl)acetamide-kerosene using hollow fiber membrane extractor
YANG Zhu xian,DU Hui fang,SUN Xian bo,XIA Ye,ZHOU Zu ming,
YANG Zhu-xian
,DU Hui-fang

环境科学学报(英文版) , 2001,
Abstract: Extraction kinetics of phenol with N,N di(1 methyl heptyl) acetamide kerosene using hollow fiber membrane extractor has been studied. The rate regularities and kinetic types of forward and backward extraction were obtained respectively by determining the forward and backward extraction rate under various experimental conditions. The mass transfer mechanism was discussed. Both the forward and backward extraction of phenol might be controlled by diffusion processes, and the diffusion resistance for both forward and backward extraction mainly exists in aqueous phase. In addition, ways to optimize the extraction process of phenol were discussed as well.
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