Artificially creating electrochemical sites by the induced copper dissolution with STM tips

[中文文摘]在电极电位稍负于其Nernst电位时 ,较正的探针电位可以诱导铜表面的局域刻蚀 ;同时 ,利用这一诱导刻蚀可以方便地人工构筑电极表面电化学活性位或特定的纳米结构 ,如现场构筑坑 (pit)、螺旋岛 (spiralisland)和岛 (island)等电化学活性位 ;并现场研究它们相关的 (电 )化学反应。[英文文摘]STM tip was found to be able to induce local dissolution of copper by applying a rather positive tip potential while the electrode is controlled at a cathodic potential of bulk copper deposition in dilute Cu 2+ solution. Furthermore, we present the possible artificially creating of electrochemical sites by using induced copper dissolution with STM tip. Spiral islands, normal islands and pits were easily created. The crystal growth on the artificial islands during the electrodeposition was followed.国家自然科学基金; 教育部高等学校博士点基金资助项目 (20173046)

400 Gbit/s FR4光收发模块的研究

如今数据中心的业务流量需求急剧上升，很多服务商早已开始着手400 Gbit/s以太网通信系统的建设。相比于100 Gbit/s光模块，400 Gbit/s光模块可提供更高的传输带宽以及更低的功耗和成本。针对上述需求，文章提出了一种应用于数据中心光通信网络系统的400 Gbit/s光收发模块设计方案。首先介绍了400 Gbit/s光模块的相关协议及标准，然后给出了模块的总体设计框架，主要从速率转换、发射、接收和监控4部分进行了阐述，最后对该模块进行了测试。测试结果表明，该模块符合各项协议与标准的规定，是一种能实现数据中心400 Gbit/s以太网传输的良好解决方案

In-stiu STM tip-induced localized etching of Ag(111)

[中文文摘]本文报道用现场扫描隧道显微镜技术 (in situSTM)研究Ag( 1 1 1 )电极表面局域刻蚀。实验表明 ,STM针尖可以诱导有Iˉ特性吸附的Ag( 1 1 1 )电极在其电化学稳定区发生表面局域刻蚀 ,刻蚀的发生与程度与针尖电位、样品电位及偏压等因素有紧密关系 ,刻蚀速度在偏压最小时达最大。刻蚀的发生也间接反映了电化学体系中的多重隧穿途径及其随电极电位的变化。[英文文摘]We reported STM tip induced localized etching of Ag(111)surface under electrochemical control. It has been shown that the induced etching by W tip can take place in the presence of I in alkaline solution at the potential where it is electrochemically stable without the tip involvement. The etching rate crucially depends on the tip electrode potential, which reaches maximum when bias voltage approaches zero. The influence of the tip materials, the tip potential as well as the sample potential was discussed, which indirectly indicate a multiple tunneling mechanism in the electrolyte.国家自然科学基金 (No.29833060); 国家教委优秀年轻教师基金; 教育部博士点基金资助项目

碳酸钙填充硅酮密封胶弹性回复性能研究初探

以α,ω-二羟基聚二甲基硅氧烷(107胶)、二甲基硅油(201)以及自制碳酸钙为主要原料制备了硅酮密封胶,研究了107胶分子量,二甲基硅油用量,碳酸钙的比表面积、表面改性以及微观形貌等对硅酮密封胶弹性回复性能的影响。实验结果表明,适当提高107胶黏度、增加硅油用量、降低碳酸钙比表面积、增加碳酸钙表面处理剂用量或采用形貌规整的立方形纳米碳酸钙,均有利于改善碳酸钙填充硅酮密封胶弹性回复性能

Application of Electrochemical Scanning Probe Microscopes in Characterization and Modification of Solid liquid Interfaces

[中文文摘]固－液界面（主要指电化学界面）是进行物理化学过程的重要场所，而界面的微观结构起着十分关键的作用．电化学扫描探针显微镜（ＥＣＳＰＭ）已成为研究固－液界面结构的有力的工具．主要包括电化学扫描隧道显微镜（ＥＣＳＴＭ）、电化学原子力显微镜（ＥＣＡＦＭ）和扫描电化学显微镜（ＳＥＣＭ）．结合实验室近年来的研究工作和最新结果，从方法论的角度讨论ＥＣＳＰＭ特点、固－液体系在ＥＣＳＰＭ表面研究和表面修饰加工中所具有的独特优势以及研究动向．[英文文摘]The microscopic structure of the solid liquid interfaces (mainly the electrochemical interfaces) plays important roles to physico chemical processes taking place in the interfaces. Electrochemical scanning probe microscopes (ECSPM) have become one of the most powerful techniques for studies of solid liquid interfaces. Electrochemical scanning tunneling microscopy (ECSTM),electrochemical atomic force microscopy (ECAFM) and scanning electrochemical microscopy (SECM) are the major techniques under the catego ry of ECSPM. Based on authors’work, the paper has described unique advantages of ECSPM in characterizat ion and modification of so lid-liquid interfaces from the methodo logical point of view.国家自然科学基金, 国家教委优秀年轻教师基金

STUDIES ON THE NATURE OF SMPI AND PROMOTER ACTION IN Rh-Nb_2O_5/SiO_2 CATALYSTS FOR SYNGAS CONVERSION TO ETHANOL

[中文摘要]使用负载型催化剂由合成气制乙醇是一碳化学研究的一个重要发展。本实验室前已报道用化学反应法检验出Rh-Nb_2O_5/SiO_2表面上除了铑位外同时还存在氧化铌位。本文为兰部分工作所组成:(1)进一步用氢还原过的Nb_2O_5/SiO_2催化乙炔聚合成聚乙炔的化学方法推断Rh-Nb_2O_5/SiO_2上可能存在着Nb—H键。(2)用FTIR法检测上述催化剂的红外光谱吸收带,1740(w)cm~(-1)为V_(Rh-H),1560cm~(-1)(broad,m)、1269cm~(-1)(s)为与Nb—H有关的吸收,后者可能属于桥式的吸收。(3)XPS检测出合成气处理的Rh-Nb_2O_5/SiO_2表面上存在Rh~0、Rh~Ⅰ、Nb~Ⅴ、Nb~Ⅳ和两种不同的沉积碳。根据这些结果,提出活性中心可能为A(参见正文图3)简写为B(见图3),CO转化的主要途径是而后C—O还原断裂生成=,再与偶联为,最后还原为乙醇或乙醛。根据实验结果对本体系催化剂中SMPI和助催剂作用的实质作了讨论。[英文摘要]Syngas conversion to ethanol by supported catalysts is an important progress in C_1 chemistry.It has been reported by our laboratory that Rh sites and niobia sites coexisted on Rh-Nb_2O_5/SiO_2 catalysts as detected by means of reaction chemi- stry involving the catalytic aromatization and polymerization of acetylene on such catalysts.This paper reports a further study consisting of the following three parts: (1)The probable existence of Nb-H bonds on hydrogen-reduced Rh-Nb2O5/SiO2 was deduced from the catalytic activity toward polymerization of acetylene to polyacetylene and the loss of catalytic activity toward cyclotrimerization of acetylene of such catalysts.(2)The FTIR spectra of the above mentioned catalysts were studied.The peak at 1740 cm-1(vw) may be assigned to VRh-H,that at 1560 cm-1 (m,broad) to VNh-H,while that at 1269 cm-1 (s) most probably to a bridging species,Rh-H-Nb.(3)The existence of Rh0,RhI,Nbv,NbIV and two types of carboneceous deposits on syngas treated Rh-Nb2O5/SiO2 catalysts was detected by XPS;A model of active center,A(cf.Fig.3)(abbr.B),formed by partial reduction of niobia through hydrogen spillover and "wetting" or partial coating of the surfaces of rhodium particles (Rh0xRhIY)by the partially reduced niobia,has been proposed.By analogy with knomn organometallic chemistry,the major reaction pathway might involve migratory insertion of chemisorbed species C to form E,hydrogenation to F cis-coupling with CO to form coordinated ketene,and further hydrogenation to ethanol or aldehyde with simultaneous regeneration of the active site by hydrogenation and elimination of H2O;while methane CH4 was produced by hydrogenation and elimination of H2O;while methane CH4 was produced by hydrogenation of the coordinated carbence CH2 in a secondary reaction pathway.The true nature of SMPI in the present system has also been discussed.中国科学院科学基金资助的课

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies