Institutional Environment, CEO Demographic Characteristics and Corporate Cash Holdings

本文实证研究了制度环境、CEO背景特征对现金持有行为的影响。研究结果发现,CEO学历越高、任期越短,以及不具有金融、会计或经济管理类专业背景的公司的现金持有量更高;CEO年龄对现金持有量并没有显著影响。进一步研究发现,在不同制度环境(市场化进程和产权性质)下,CEO背景特征对现金持有量的影响存在较大差异。本文的研究结论丰富了现金持有量影响因素方面的文献,拓展了高层梯队理论在公司财务领域中的应用。The extant literature ignores the influence of idiosyncratic manager-specific features on corporate decisions such as cash holdings, and more and more scholars are focusing on how executives' characteristics influence corporate behaviors due to their heterogeneity.This paper examines the impact of CEO demographic characteristics on corporate cash holdings as well as the different effects under different institutional environment.Our empirical results suggest that corporate cash holdings are positively associated with CEO educational level, and negatively associated with CEO tenure.Besides, CEOs with professional background of finance, accounting, economic and management hold less cash.In a further study of introducing the marketization process and enterprise property variables, we find that there is some difference in the relationship between CEO demographic characteristics and corporate cash holdings under different institutional environment.Arguably, the above conclusion enriches previous literature on the determinants of corporate cash holdings, and expands the application of Upper Echelons Theory in the field of corporate finance.国家自然科学基金项目(71302072

高转速气驱研抛装置设计及研抛特性研究

针对传统磨削中电主轴体积大和转速低的问题,设计了一种高转速、小体积气驱研抛装置。通过理论计算对轴承承载力进行了分析,并在有限元软件中建立了装置的仿真模型,对装置刚度、固有频...福建省科技计划项目(2017H0036

NMR Studies on Interactions between Diperoxovanadate Complex and 3-Substituted Pyridines

为探讨有机配体上取代基团对反应平衡的影响,在模拟生理条件下(0.15mol/LNaCl溶液),应用多核(1H、13C和51V)多维(DOSY)以及变温NMR技术研究双过氧钒配合物[OV(O2)2(D2O)]-/[OV(O2)2(HOD)]-(简写为dpV)与3-取代吡啶的相互作用,并首次报道了一些物种的NMR化学位移.dpV与有机配体的反应性从强到弱的顺序为:吡啶>烟酸根>烟酸甲酰胺≈烟酸甲酯,这说明吡啶环上取代基影响反应平衡.竞争配位导致一系列新的6配位的过氧钒物种生成.密度泛函计算结果合理地解释了实验结果,并表明溶剂化效应在反应中起重要作用.To understand the substituting group effects of organic ligands on the reaction equilibrium, the interactions between a diperoxovanadate complex [OV(O2)2(D2O)]-/[OV(O2)2(HOD)]- (abbr. dpV) and a series of 3-substituted pyridines in solution were explored using multinuclear (1H, 13C, and 51V) magnetic resonance, DOSY, and variable temperature NMR in 0.15 mol/L NaCl ionic medium for mimicking the physiological condition. Some direct NMR data were given for the first time. The reactivity among the 3-substituted pyridines towards dpV takes the order of pyridine>nicotinate>N-methyl nicotinamide≈ methyl nicotinate. The competitive coordination results in the formation of a series of new six-coordinated peroxovanadate species [OV(O2)2L]n- (L=3-substituted pyridines, n=1 or 2). The results of density func-tional calculations provided a reasonable explanation of the relative reactivity of the 3-substituted pyridines. Solvation effects play an important role in these reactions.国家自然科学基金(Nos.20772027,20803020);; 973子课题(No.2003CB716005);; 湖南省自然科学基金(No.06JJ30004);; 中国博士后科学基金(No.20070410805);; 湖南省教育厅青年项目(No.06B028);; 固体表面物理化学国家重点实验室资助项目;; 湖南科技大学博士基金(No.E-55107)资助项

NMR Studies on Interactions between Diperoxovanadate and Imidazole-like Ligands

为探讨咪唑环上取代基团对反应平衡的影响,在模拟生理条件(0.15 mol·L~(-1)NaCl溶液)下,应用多核(~1H、~(13)C和~(51)V)、扩散排序谱(DOSY)以及变温NMR等谱学技术研究双过氧钒配合物NH_4[OV(O_2)_2{2-(2'-Pyri-dine)- [midazole}]·4H_2O(简写为bpV(Imi-Py))和咪唑类配体(咪唑、2-甲基-咪唑、4-甲基-咪唑和组氨酸)的相互作用,其从强到弱的顺序为咪唑≈4-甲基-咪唑>2-甲基-咪唑>组氨酸.研究结果表明,咪唑环上取代基团空间位阻对反应平衡产生较大影响,同时竞争配位的结果导致新的6配位过氧物种[OV(O_2)_2L]~-(L为咪唑类配体)的生成,当配体为4-甲基-咪唑和组氨酸时,生成的则是一对异构体.To understand the substituting effects of imidazole ring on the reaction equilibrium,the interactions between diperoxovanadate complex NH_4[OV(O_2)_2{2-(2'-Pyridine)-Imidazole}]·4H_2O (abbr.bpV(Imi-Py)) and a series of imidazole-like ligands (imidazole,2-methyl-imidazole,4-methyl-imidazole,and histidine) in solution were explored using multinuclear (~1H,~(13)C,and ~(51)V) magnetic resonance,diffusion ordered spectroscopy (DOSY),and variable temperature NMR in 0.15 mol·L~(-1) NaCl ionic medium for mimicking the physiological conditions.The experimental results indicated that the activities of bpV(Imi-Py) and organic ligands were as follows:imidazole≈4-methyl-imidazole>2-methyl- imidazole>histidine.The stedc effect of the organic ligands affects the reaction equilibrium.At the same time,new six- coordinated peroxovanadate species [OV(O_2)_2L]-(L=imidazole-like ligands) were formed due to the competitive coordination between 2-(2'-pyridyl)-imidazole and the imidazole-like ligands.When the ligand was 4-methyl- imidazole or histidine,a pair of isomers was formed.国家自然科学基金(20772027);; 973子课题(2003CB716005);; 湖南省自然科学基金(06JJ30004);; 中国博士后科学基金(20070410805);; 湖南省教育厅青年项目(068028);; 卫生部(福建省)卫生教育联合攻关计划(3502220051027);; 厦门市重大疾病攻关研究基金(Wkj2005-2-019);; 固体表面物理化学国家重点实验室开放基金和湖南科技大学博士基金(E55107)资

半群OPP IE*（X）的秩

设X为有限全序集,E为X上的凸等价关系.令OPP IE*（X）为所有E类方向保序变换所构成的半群,得到了OPP IE*（X）的秩

可调光功率分配器的应用

介绍了光迅科技有限责任公司研发的宽范围可调光功率分配器,描述了该产品在光纤到户（FTTH）、光线路保护和各种光网络中的可能应用

Application of Industrial Wireless Technology Based on WIA-PA in the Simulation & Optimization of Circulating Water System

本文介绍了基于WIA-PA的工业无线网络技术在循环水模拟优化系统中的应用案例。文中分别介绍了循环水系统模型、WIA-PA工业无线网络架构及应用无线网络技术进行数据采集与通讯的循环水系统管控平台。工业无线网络技术所具备的易安装、低成本等优点在该系统中得到了很好地发挥

Effects of Y~(3+) Dopant on the Photoinduced Superhydrophilicity of Thin Nanostructured Titania Films and its Mechanism

[中文文摘]用溶胶-凝胶法和浸渍-提拉法工艺,在玻璃表面上制备了均匀、透明的钇离子(Y3+)掺杂二氧化钛纳米薄膜。用XRD分析了样品的晶相及其与热处理温度的关系,用X射线光电子能谱(XPS)分析了薄膜表面氧的状态,用可见光吸收光谱分析了涂膜层数对透光率的影响,用接触角仪测定了其亲水性。研究了Y3+掺杂本身和具体的掺杂量、光照强度和时间对薄膜亲水性的影响。研究结果表明,掺杂Y3+的二氧化钛纳米薄膜,在物质的量分数x(Y3+/Ti4+)=1.5%时,经紫外光照30min或自然光照1h后,与水的接触角小于5°,表现出超亲水性;与纯二氧化钛纳米薄膜相比,其超亲水性对光诱导更为敏感;在有实用意义的超亲水性的稳定方面也有明显的改善;这应部分地与固体化学所描述的Y3+掺杂所造成固定、额外并且是高浓度的氧空位有关。[英文文摘]Homogeneous and transparent thin nanostructured titania films doped by Y3+were prepared on glass substrates by sol gel processing and dip coating technique. The films were characterized by XRD, XPS and visible absorption spectra. The hydrophilicity of the films was determined by measuring the water contact angles for the films. The effects of Y3+doping, the quantities of Y3+dopant, and the intensity and the time of light illumination on hydrophilicity of the films were studied. The results revealed that the film at a mole percent of x(Y3+ /Ti4+)=1.5% had a water contact angle of less than 5 after UV illumination for 30min or sunlight for 1h, showing superhydrophilicity, compared with the pure titania ones.This might partly be relative with the fixed, extra and highly concentrated oxygen vacancied resulted from Y3+ doping,the mechanics of which were as described in the solid state chemistry

NMR and Theoretical Studies on Interactions between Biperoxovanadate and 4,4'-bipyridine

在模拟生理条件下(0.15mol/LNaCl溶液),应用多核(1H和51V)多维(DOSY)NMR以及变温技术等谱学方法研究双过氧钒配合物[OV(O2)(2D2O)]-/[OV(O2)(2HOD)](-简写为bpV)与4,4'-联吡啶(简写为bipy)的相互作用.竞争配位的结果,导致溶液中既有6配位的过氧钒物种[OV(O2)(2bipy)]-的生成,还有([OV(O2)2)(2bipy)]2(-6配位)的存在.采用密度泛函理论(B3LYP方法),在3-21+G*水平下计算表明,bipy和bpV生成[OV(O2)(2bipy)]-和([OV(O2)2)(2bipy)]2-的ΔG分别为-53.35和-55.85kJ/mol,较好地支持了实验结果.The interaction between diperoxovanadate complex [OV(O2)2(D2O)]-/[OV(O2)2(HOD)]- (abbr. bpV) and 4,4′-bipyridine (abbr. bipy) in solution were explored using multinuclear (1H and 51V) magnetic resonance, DOSY, and variable temperature NMR in 0.15 mol/l NaCl ionic medium for mimicking the physiological conditions. Competitive coordination interactions result in two new six-coordinated peroxovanadate species, [OV(O2)2(bipy)]- and [(OV(O2)2)2(bipy)]2-, respectively. The density functional theory calculations based on 3-21+G* indicated that the free energies of the form of [OV(O2)2(bipy)]- or [(OV(O2)2)2(bipy)]2- is -53.35 and -55.85 kJ/mol, which provided a reasonable explanation on the experimental results.国家自然科学基金资助项目(20772027);; 973子课题(2003CB716005);; 湖南省自然科学基金资助项目(06JJ30004);; 中国博士后基金(20070410805);; 湖南省教育厅青年项目(06B028);; 卫生部(福建省)卫生教育联合攻关计划(3502Z20051027);; 厦门市重大疾病攻关研究基金资助项目(Wkj2005-2-019);; 固体表面物理化学国家重点实验室开放基金资助项

Optimum design of PID controllers using only a germ of intelligence

The social foraging behaviour theories of many species provide us with consistent hints to algorithmic approaches for the design of powerful intelligent optimization technology, with direct applications in a high variety of social sciences and engineering fields. In this paper a novel design method for determining the optimal proportional-integral-derivative (PID) controller parameters based on the foraging behaviour of E. coli bacteria is proposed. Bacterial foraging (BF) scheme is selected since it represents an earlier proposal for distributed optimization and control based on natural foraging capacities. The PID controller designed using this method is called the BF-PID controller. In order to assist estimating the performance of the proposed BF-PID controller, a new time-domain performance criterion function was also introduced. To show the validity of the proposed method, two typical control systems were tested. Comparisons with the genetic algorithm (GA) are presented and discussed