后趋同时代的权益资本成本异质性分析

本文以我国A股上市公司会计准则趋同前后的数据为样本,采用多元回归方法和双重差分分析,并控制了股权分置改革的影响,对趋同后权益资本成本的下降进行异质性分析,并检验引致异质性的潜在制约因素。研究发现趋同后国有控股公司比非国有控股公司的权益资本成本下降得更多,制度环境和管理层动机是制约非国有控股公司受益于会计准则国际趋同的重要因素。本研究厘清了会计准则国际趋同的作用机理,拓展了我国会计准则国际趋同经济后果研究。为转轨经济体有效实施会计准则国际趋同策略提供了框架思路,监管层必须注重推进外部市场化建设,并加强对管理层盈余管理的监管。国家社会科学基金重点项目(13AJY005、17BGL067);;教育部人文社会科学重点研究基地重大项目(16JJD790035);;福建省社科基金(FJ2016B243);;国家自然科学基金(71402114)的资

基于双岛结构的多晶硅纳米薄膜压力传感器

为解决传统半导体压力传感器温度特性差、非线性度高等问题,设计一种基于双岛结构的多晶硅纳米薄膜压力传感器。利用有限元分析软件分析硅膜结构的应力分布规律,确定力敏电阻的最佳布局,进一步提高了传感器的灵敏度。这种压力传感器兼具温度特性好、灵敏度高、线性度好等综合性能。福建省科技厅引导性(重点)项目(2017H032);;莆田学院激光精密加工工程技术研究中心开放基金项目(2016JZA014

中央苏区图书馆文献资源的采集工作研究

中央苏区时期,面对敌人的经济封锁和刚起步的图书出版发行工作,图书馆文献资源采集工作异常艰难。在党和苏维埃政府颁布的一系列法规和指令下,中央苏区的工作者明确了文献资源的采集原则,开拓多方渠道加强了文献资源采集工作,为当今图书馆文献资源采集工作提供借鉴和参考

基于词向量空间的大规模中文语义网络构建与复杂性分析

当前对于汉语语义层次的语言网络研究方法仅限于静态词典生成以及人工手动生成两种方法,具有很大的局限性。对此,该文从大规模语料库生成的语义空间出发,结合语义空间丰富的语义信息和义类词典资源,提出一种新颖的基于分布语义的语义网络构建策略,并在此基础上探究了由不同性质的语义空间所构建的语义网络的统计特性。相比前人的方法,该文提出的方法优势在于无需依赖人工标注,支持大规模动态语料的网络自动构建。实验结果表明,语义网络具有复杂网络两个典型的特性:小世界效应和无标度特性。此外,由于语义网络描述的是词之间最为本质的语义关系,与不同文体中的措辞、使用习惯、风格等不存在直接的关系,因此当语义网络节点到达一定规模时,语义网络的某些统计特性可能会趋于一致

Ge/GeO/多层石墨纳米复合物锂离子电池负极材料性能研究

由于其高容量、快速锂离子扩散速率和高电导性的优点,锗被认为是一种非常有前景的锂离子电池负极材料.本研究利用GeO2和石墨作为前驱体,通过水热法制备Ge/GeO/多层石墨复合物并将其应用于锂离子电池负极材料进行电化学性能研究.实验结果表明,Ge/GeO2纳米粒子的粒径约为40 nm.该复合物电极的第一次充放电容量分别是2045和1146 mA h g.1,库仑效率为56.0%.50圈充放电循环后,当电压范围为0.01.50 V时,容量保持在1008 mAhg.倍率实验表明,该电极在1C(1C=1000mAg)和2 C倍率大电流下,虽然容量略有衰减,但仍保持790和710 mAhg的高容量.教育部新世纪优秀人才计划(编号:NCET-13-0879)；福建省闽江学者特聘教授计划；泉州市桐江学者特聘教授计划；福建省自然科学基金(编号:2016J01069)资助项目

Application of Ti/RuO2-IrO2-SnO2-Sb2O5 Anode in Rural Drinking Water Disinfection

采用热分解法制备了一种新型高效析氯阳极Ti/RuO2-IrO2-SnO2-Sb2O5,将其应用于农村饮用水消毒频繁停开、低电解液浓度的特殊工况下,并与Ti/RuO2-SnO2-Sb2O5、Ti/RuO2-TiO2、Ti/RuO2-TiO2-IrO2三种析氯阳极进行性能对比。通过SEM、EDS、XRD等方法表征测试阳极表面形貌、元素及组成,考察了氯化钠浓度、电流密度、停开频率对阳极析氯效果和寿命的影响。研究发现,Ti/RuO2-IrO2-SnO2-Sb2O5阳极活性强、稳定性高;阳极涂层各组分高度融合为固溶体,结构致密,稳定性强;在15 g·L-1 NaCl、400 A·m-2电流密度、20℃条件下,Ti/RuO2-IrO2-SnO2-Sb2O5阳极电解的电流效率达到91.55%;频繁停开、强化电解条件下寿命达到231 h,是Ti/RuO2-TiO2阳极的77倍,预估在400 A·m-2电流密度下能够使用20年。Sodium hypochlorite disinfection has many advantages, including reliable operation, low cost, easily available raw materials. It is, therefore, suitable for disinfection of drinking water in remote rural areas. The service life and chlorine evolution efficiency of the anode are the main factors restricting the performance of the sodium hypochlorite generator. The special conditions of frequent shutdown and low electrolyte concentration in the rural drinking water application also put forward high requirements on the performance of the anode. In this study, Ti/RuO2-IrO2-SnO2-Sb2O5,a new-type and efficient chlorine evolution anode, was prepared by thermal decomposition method and further applied to disinfection of drinking water in rural areas. Comparison was also made between this anode with Ti/RuO2-SnO2-Sb2O5, Ti/RuO2-TiO2 and Ti/RuO2-TiO2-IrO2 anodes. The surface morphology, elements and composition of the anodes were examined by SEM, EDS and XRD. The effects of sodium chloride concentration, current density and shutdown frequency on chlorine evolution efficiency and lifetime of the anodes were also investigated. It was found that the Ti/RuO2-IrO2-SnO2-Sb2O5 electrode exhibited strong activity and high stability, and its coating components were highly fused into a solid solution with dense structure and great stability. The current efficiency of Ti/RuO2-IrO2-SnO2-Sb2O5 anode reached 91.55% in 15 g·L-1 NaCl solution at 400 A·m-2 and 20℃. In the enhanced electrolysis lifetime experiment, the service lifetime of Ti/RuO2-IrO2-SnO2-Sb2O5 anode reached 231 h, which was 77 times longer than that of Ti/RuO2-TiO2 anode. It was estimated that the Ti/RuO2-IrO2-SnO2-Sb2O5 anode could be used for 20 years under the current density of 400 A·m-2. Therefore, compared with the traditional electrode materials, Ti/RuO2-IrO2-SnO2-Sb2O5 achieved higher chlorine evolution efficiency and stability. It could be used for a long time in the condition of frequent shutdown and low electrolyte concentration. Besides, it could greatly reduce the equipment operation cost, the raw material feeding frequency and the impurities introduction. Thus, the Ti/RuO2-IrO2-SnO2-Sb2O5 anode developed in this studymight be suitable for rural drinking water disinfection application.国家重点研发计划项目(2019YFC0408800)通讯作者:陈雪明E-mail:[email protected]:Xue-MingChenE-mail:[email protected]浙江大学环境与资源学院,浙江 杭州 310058College of Environmental & Resource Sciences of Zhejiang University, Hangzhou 310058, Zhejiang, Chin

Electrochemical fabrication and interfacial charge-transfer process of Ni/GaN(0001) electrodes

The electrodeposition of Ni on single-crystal n-GaN(0001) film from acetate solution was investigated using scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analysis, atomic force microscopy, and electrochemical techniques. The as-deposited Ni/n-GaN(0001) had a flat band potential of U-fb = -1.0 V vs. Ag/AgCl, which was much lower than that of bare GaN(0001). That is, a more feasible charge-transfer process occurred at the Ni/n-Ga(0001) interface. On the basis of a Tafel plot, an exchange current density of similar to 166 x 10(-4) mA cm(-2) was calculated. The nuclei density increased when the applied potential was varied from -0.9 V to -1.2 V and, eventually the whole substrate was covered. In addition, the current transient measurements revealed that the Ni deposition process followed instantaneous nucleation in 5 mM Ni(CH3COO)(2) + 0.5 M H3BO3

Study on Schottky barrier of 4H-SiC at different anealing temperature

采用磁控溅射的方法在4H-SiC样品上分别沉积四种金属薄膜(Ag,Cu,Ni,Cr)形成Schottky 接触,研究了不同温度退火对Schottky势垒高度的影响。通过对样品的I-V测试结果的拟合,得到各金属/4H-SiC Schottky接触的势垒高度以及理想因子。在反向偏压100V下,样品的反向漏电流小于10-10A,说明样品的反向特性良好。样品经过不同温度的退火后,发现Cu、Ni与4H-SiC的势垒高度(SBH)随退火温度的升高而提高,超过某一温度,其整流特性变差; Ag、Cr的SBH在退火后降低。SBH与金属功函数呈线性关系(Cr金属除外),斜率为0.11。Schottky barriers were formed by sputtering the metals on the front side of 4H-SiC(Si face) by magnetron sputtering to study the rectifying characteristics of the contacts between the metals and 4H-SiC. The infections of the annealing under different temperature were also studied. Schottky barrier height (SBH) of metal/4H-SiC was evaluated from I-V measurements. Under a reverse voltage about 100 V, the reverse leaky current is below 0.1 nA. After annealed, the SBH of Cu/, Ni/4H-SiC was increased, but the SBH of Cr/, Ag/4H-SiC contact was decreased. The relationship between the work function of metals and the SBH was presented. The barrier height depends on the metal work function with slopes of 0.1 to 0.2 (except metal Cr).福建省厦门市科技项目(3502Z20031076

Aripiprazole versus other atypical antipsychotics for schizophrenia

BACKGROUND: In most western industrialised countries, second generation (atypical) antipsychotics are recommended as first line drug treatments for people with schizophrenia. In this review we specifically examine how the efficacy and tolerability of one such agent - aripiprazole - differs from that of other comparable second generation antipsychotics. OBJECTIVES: To evaluate the effects of aripiprazole compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses. SEARCH METHODS: We searched the Cochrane Schizophrenia Group Trials Register (November 2011), inspected references of all identified studies for further trials, and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information. SELECTION CRITERIA: We included all randomised clinical trials (RCTs) comparing aripiprazole (oral) with oral and parenteral forms of amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone or zotepine for people with schizophrenia or schizophrenia-like psychoses. DATA COLLECTION AND ANALYSIS: We extracted data independently. For dichotomous data we calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. Where possible, we calculated illustrative comparative risks for primary outcomes. For continuous data, we calculated mean differences (MD), again based on a random-effects model. We assessed risk of bias for each included study. MAIN RESULTS: We included 12 trials involving 6389 patients. Aripiprazole was compared to olanzapine, risperidone and ziprasidone. All trials were sponsored by an interested drug manufacturer. The overall number of participants leaving studies early was 30% to 40%, limiting validity (no differences between groups).When compared with olanzapine no differences were apparent for global state (no clinically important change: n = 703, 1 RCT, RR short-term 1.00 95% CI 0.81 to 1.22; n = 317, 1 RCT, RR medium-term 1.08 95% CI 0.95 to 1.22) but mental state tended to favour olanzapine (n = 1360, 3 RCTs, MD total Positive and Negative Syndrome Scale (PANSS) 4.68 95% CI 2.21 to 7.16). There was no significant difference in extrapyramidal symptoms (n = 529, 2 RCTs, RR 0.99 95% CI 0.62 to 1.59) but fewer in the aripiprazole group had increased cholesterol levels (n = 223, 1 RCT, RR 0.32 95% CI 0.19 to 0.54) or weight gain of 7% or more of total body weight (n = 1095, 3 RCTs, RR 0.39 95% CI 0.28 to 0.54).When compared with risperidone, aripiprazole showed no advantage in terms of global state (n = 384, 2 RCTs, RR no important improvement 1.14 95% CI 0.81 to 1.60) or mental state (n = 372, 2 RCTs, MD total PANSS 1.50 95% CI -2.96 to 5.96).One study compared aripiprazole with ziprasidone (n = 247) and both the groups reported similar change in the global state (n = 247, 1 RCT, MD average change in Clinical Global Impression-Severity (CGI-S) score -0.03 95% CI -0.28 to 0.22) and mental state (n = 247, 1 RCT, MD change PANSS -3.00 95% CI -7.29 to 1.29).When compared with any one of several new generation antipsychotic drugs the aripiprazole group showed improvement in global state in energy (n = 523, 1 RCT, RR 0.69 95% CI 0.56 to 0.84), mood (n = 523, 1 RCT, RR 0.77 95% CI 0.65 to 0.92), negative symptoms (n = 523, 1 RCT, RR 0.82 95% CI 0.68 to 0.99), somnolence (n = 523, 1 RCT, RR 0.80 95% CI 0.69 to 0.93) and weight gain (n = 523, 1 RCT, RR 0.84 95% CI 0.76 to 0.94). Significantly more people given aripiprazole reported symptoms of nausea (n = 2881, 3 RCTs, RR 3.13 95% CI 2.12 to 4.61) but weight gain (7% or more of total body weight) was less common in people allocated aripiprazole (n = 330, 1 RCT, RR 0.35 95% CI 0.19 to 0.64). Aripiprazole may have value in aggression but data are limited. This will be the focus of another review. AUTHORS' CONCLUSIONS: Information on all comparisons are of limited quality, are incomplete and problematic to apply clinically. Aripiprazole is an antipsychotic drug with a variant but not absent adverse effect profile. Long-term data are sparse and there is considerable scope for another update of this review as new data emerges from the many Chinese studies as well as from ongoing larger, independent pragmatic trials