A Preliminary Study of Influence of the Chain Length of Alkanethiols on the Electrochemical Behavior of Redox Self-Assembled Multilayer Thin Films

以烷基硫醇和二茂铁衍生物构建的氧化-还原自组装多层膜为模型体系,研究烷基硫醇分子链长对多层膜电化学行为的影响.实验表明,二茂铁基团和电极之间的电子传递反应速率随两者距离的增加呈现指数级下降的趋势;烷基硫醇分子链长对自组装膜电化学行为的影响于不同情况下表现不同.本实验条件下,当多层膜上的电活性基团与电极比较接近时,长链分子自组装膜呈现较强的电化学响应.而当电极与电活性基团之间的距离较远时,短链烷基硫醇分子自组装膜呈现较强的电化学响应.Alkanethiols and ferrocene derivates were used to construct redox self-assembled double-or triplex-layer thin films, which acted as a model of redox self-assembled multilayer thin films (SAMTFs) to study the in-fluence of alkanethiols chain length on the electrochemical behavior of the SAMTFs. The rate of electron transferreaction decreased exponentially with the distance between the Fc groups and the underlying electrodes. The in-fluence of chain length on the electrochemical behaviors of the SAMTFs was inconsistent under different situa-tions. On the experimental situation of this work, when electroactive groups were closer to the electrodes,SAMTFs by longer chains of alkanethiols displayed stronger electrochemical responses, while when distance be-tween electroactive groups and electrodes was extended, SAMTFs by shorter chain would present more obviouselectrochemical responses.作者联系地址：中国科学院研究生院化学系,中国科学院研究生院化学系 北京100049 ,北京100049Author's Address: Department ofChemistry, Graduate School, Chinese Academy ofSciences, Beijing100049, Chin

Electrocatalytic Oxidation of Formic Acid on Pd/Ni Heterostructured Catalyst

通过两步还原法制备了Pd/Ni双金属催化剂.由于金属Pd原子在先行还原的Ni纳米粒子表面的外延生长以及其在Ni表面及Pd表面生长表现出的吉布斯自由能差异，最终导致了异结构Pd/Ni纳米粒子的形成.高分辨电子透射显微镜结果证实了异结构的存在，然而X射线衍射测量表明Pd/Ni纳米粒子具有类似于Pd的面心立方结构.制备的Pd/Ni纳米粒子与同等条件下合成的Pd纳米粒子相比对甲酸氧化呈现了更高的电催化活性，而且电催化稳定性也要明显优于纯Pd纳米粒子，证明Pd/Ni双金属催化剂是可选的直接甲酸燃料电池阳极催化剂.双金属催化剂对甲酸氧化电催化活性和稳定性增强可能是Ni原子的修饰改变了Pd粒子表面配位不饱和原子的电子结构所致.A Pd/Ni bimetallic nanostructured electrocatalyst was fabricated via a two-step reduction route. Owing to an epitaxial growth of Pd atoms on the surface of Ni nanoparticles, heterostructured Pd/Ni nanocomposites were formed and verified by high resolution transmission electron microscopy combined with energy-dispersion X-ray spectroscopy. X-ray diffraction confirmed that the as-prepared Pd/Ni nanocomposites possessed a single face-centered-cubic (fcc) Pd structure, probably due to a weaker diffraction intensity of metallic Ni and/or overlapping by that of Pd. The intrinsic catalytic activity on the Pd/Ni is higher than that on the Pd. Moreover, the durability of formic acid oxidation on the Pd/Ni was much enhanced over the Pd nanoparticles. The change in electronic structure of the surface coordination unsaturated Pd atoms and the possible dissolution of Ni species from the Pd/Ni heterostructure may account for such an improved durability for formic acid oxidation.This work was supported by the National Basic Research Program of China (973 Program) (No. 2012CB932800), the Natural Science Foundation of China (No. 21073219), Shanghai Science and Technology Committee (No. 11DZ1200400) and the Knowledge Innovation Engineering of the CAS (No. 12406, 124091231).This work was supported by the National Basic Research Program of China (973 Program) (No. 2012CB932800), the Natural Science Foundation of China (No. 21073219), Shanghai Science and Technology Committee (No. 11DZ1200400) and the Knowledge Innovation Engineering of the CAS (No. 12406, 124091231).作者联系地址：1. 中国科学院上海高等研究院，上海 201210；2. 中国科学院研究生院，北京 100039Author's Address: 1. Shanghai Advanced Research Institute, Chinese Academy of Sciences CAS, Shanghai 201210, China; 2. Graduate School of the CAS, Beijing 100039, China通讯作者E-mail：[email protected] & [email protected]

Impact of Urbanization Intervention on Investment Efficiency of Enterprises:Evidence from Listed Companies

张亦春，厦门大学经济学院教授、博士生导师；周杰峰，厦门大学经济学院博士研究生。【中文摘要】在我国,地方政府是城镇化建设的主力，为了追求经济增长等目标，地方政府具有引导企业加大投资，以推动城镇化的相关建设的冲动。土地是重要的生产资料,且土地出让市场由地方政府所垄断,所以地方政府通过干预土地市场，可能影响到企业的投资效率。以我国2003—2013年A股上市公司的数据进行实证研究，结果表明,提高每单位土地出让面积的就业人口，会显著降低企业因为现金流富余引发的过度投资，而且股权分散度高的企业和非国有企业，受到的影响会更加显著。因此,限制地方政府的土地出让行为,能够一定程度上改善企业的投资效率。 【Abstract】In China，local governments are the main force of urbanization. In order to pursue the gal of economic growth，local governments have the impulse to gide enterprises to increase their investment to promote the related construction of urbanization.As land is an important means of production and the land transfer market is monopolized by local governments ，local governments may interfere with the efficiency of enterprises’investment by intervening in the land market. With the data of China's A-share listed companies from 2003 to 2013，the empirical results show that by increasing the employed population per unit area of land transfer，over-investment caused by surplus cash flow can be significantly reduced. Further research shows that enterprises with highly dispersed shareholding and non-state-owned enterprises，will be influenced more significantly.Therefore，restricting the land transfer of local governments can improve the investment efficiency of enterprises to a certain extent.教育部人文社科重点研究基地重大项目“中国的经济增长与经济发展”（11JJD790046);福建省社科基金一般项目“非平衡系统演化博弈与金融风险跨国分摊研究”（2009B2003

Capping effect of GaAsSb and InGaAsSb on the structural and optical properties of type II GaSb/GaAs quantum dots

<div class="aip-paragraph">We systematically study the influence of group V intermixing on the structural and optical properties of type II GaSb/GaAs quantum dots (QDs) capped by selected capping layers. Compared to GaSb QDs capped directly by a GaAs layer, we observe a strong enhancement of photoluminescence (PL) intensity and a significant red-shift of the photoluminescence peak energy to 1.35&thinsp;<em class="emphitalic">&mu;</em>m at 300&thinsp;K by the introduction of a GaAsSb capping layer. In addition, Z-contrast cross sectional transmission electron microscopy shows Sb segregation and group V mixing is greatly suppressed by GaAsSb or InGaAsSb capping layers. The new capping layers offers the possibility of controlling optical properties of type II GaSb/GaAs quantum dots and this opens up new means for achieving high efficient GaSb/GaAs quantum dot solar cell.</div

Inverse Kinematic Solution and Simulation for ROVs-Manipulators System

It is proposed to use anchor manipulators to provide a stable operating environment for underwater remotely operated vehicles (ROVs) in this paper. The kinematics equation of ROVs-Manipulators system is modeled and the motion planning of ROVs-Manipulators system (ROVMS) is described, then, a task-priority redundancy inverse kinematic solution technique based on weighted-least norm (WLN) solution is developed which address twofold aims-one for avoiding joint limit and controlling the manipulator end-effectors position, and other for limiting configuration of the ROVs vehicle. Computational aspects of the solutions are also considered in view of real-time implementation of a kinematic control algorithm. The method is applied to ROVs mounded with a five-degree-of-freedom SIWR-II Underwater-manipulator. The results from computer simulations demonstrate its effectiveness

Study of manipulator operations maneuvered by a ROV in virtual environments

It is extremely difficult to operate an underwater manipulator carried on a remotely operated vehicle (ROV) in the deep sea. In order to investigate underwater manipulator operations maneuvered by a remotely operated vehicle (ROV), this paper develops a virtual underwater manipulator and its carrier, the ROV, via the three-dimensional simulator &ldquo;Webots&rdquo; to animate operational tasks. The ROV model refers to the structure of a typical ROV which operates below the ocean&#39;s surface down to 1000&nbsp;m, while the graphical and kinematic models of the manipulator refer to a master-slave servo hydraulic manipulator with 7 functions, consisting of six degrees of freedom (DOFs) and a parallel gripper for manipulations. This study uses the virtual platform to challenge an operator to conduct different tasks by using the manipulator, including two switch-based and one master arm-based operation, and combined by remote and autonomous operations. When conducting the operations, we have considered uncertain external disturbances that stem from subsea environments. In order to demonstrate the feasibility and effectiveness of the virtual platform, we have designed two typical underwater operational tasks for training the operator: grasping a machine part in a basket, and making a circle at a specified position on the seabed. The tasks are completed by coordinating the underwater manipulator, the submersible vehicle, and a pan-tilt camera. Three operators were invited for the training operations, and their operating results are presented

Regional Cooperation and the National Business Environment:Based on a Study of the China-ASEAN Collaboration on the BRI

李一平，厦门大学东南亚研究中心/“一带一路”研究院教授、博士生导师，历史学博士；罗晶晶，厦门大学东南亚研究中心/“一带一路”研究院博士研究生；张海峰，南京财经大学财政与税务学院讲师，经济学博士。【中文摘要】作为国际合作2.0升级版的“一带一路”倡议，对沿线国家经济发展产生何种影响是非常值得研究的前沿话题。从国家营商环境改善角度，以世界银行公布的数据为基础对东盟十国营商环境进行分析，首次利用双重差分法研究共建“一带一路”对沿线东盟十国营商环境的影响可以发现，共建“一带一路”对改善沿线国家营商环境具有显著促进作用，且共建力度越强、对华经贸 合作规模越大的国家，其营商环境提升越明显。研究结论有助于国家和企业明晰投资区位，增加企业和市场主体对“一带一路”沿线国家的投资意愿和动力，也为实现沿线国家间投资贸易便利化,实现“ 一带一路”利益共同体的战略目标提供理论支持。 【Abstract】The impact of the Belt and Road Initiative (BRI) on the economic development of the participant countries in Southeast Asia is a new frontier of research. Utilizing the World Bank's data，this article examines the contribution of the BRI to the improvement of the business environment in ASEAN countries. To the best knowledge of the author，this is the first project that has employed the Differences-in-Differences method to analyze the impact of BRI collaboration on the business environment of the ten ASEAN countries. The study has found that BRI collaboration has significantly improved the business environment of the countries along the route. Closer collaborative efforts and broader economic cooperation with China mean greater improvements in the business environment of these countries. The article finds the BRI has helped enterprises identify investment locations and increased the willingness and motivation of enterprises and economic entities to invest in the countries along the BRI. Furthermore，this paper provides theoretical guidelines and empirical evidence to reduce investment and trade barriers among the countries along the BRI as well as to build a community with a shared future for mankind.福建省教育厅“一带一路”与东南亚研究院智库项目