Mechanochemical Doping of Non-metallic Elements on Oxides and their Characterization

Doping of non-metallic element such as N and S into oxide has been conducted by means of a mechanochemical method. This method is composed of two steps : the first is co-grinding the mixture of oxides and the element in air, and the second is calcining the ground sample at about 400℃. The ground sample as well as the calcined sample was characterized by a set of analytical methods, such as X-ray diffraction (XRD), Infrared spectroscopy (IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS). The chemical bonding induced by the grinding allows the doping of non-metallic element into oxide structure, while this doping is not achieved by a mechanical mixing operation of both compounds. The prepared sample exhibits agglomerated states having primary grains in nanoscale. N doped ZnO nanocrystallites show high photocatalytic ability in antibacterial test. The calcined sample TiO_S_x under irradiation of visible light with wave-length over 510 nm has shown good performance for NO gas destruction, suggesting its high photocatalytic reactivity

X射线双星系统的探测

搜寻X射线双星并建立大规模样本是解决众多科学问题(如\"银河系中有多少黑洞X射线双星?黑洞和中子星之间有无质量间隙?球状星团中有无黑洞?\"等)的基础.爱因斯坦探针卫星拥有更灵敏的探测能力,将在运行的几年之中,预计可以发现一批新的中子星和黑洞X射线双星,研究其空间和动力学质量分布成为解决上述问题的关键.国家重点研发计划(编号:2016YFA040080X);;国家自然科学基金(编号:1133305);;中国科学院战略性先导科技专项(编号:XDA15052100,XDB23040000)资助项

中国超大城市空气污染和人体健康 (APHH-Beijing) 中英联合研究计划 最终报告

Chinese versio

审计质量与事务所规模脱臼

在世界范围内注册会计师行业陷入了信任危机的背景下，证监会出台16号“双审”规定，引发千层浪。本文则致力于从事实中寻求证据，利用Simunic审计公费研究框架，通过对比本土大型会计师事务所、本土小型会计师事务所、合作所的审计公费水平与审计质量差异，探讨我国上市公司审计市场结构的现状。 与以前文献相左，本文实证结果是，相对本土小所，本土大所未能提供更高质量的审计服务，而相对本土所，合作所只是收取了更高的审计公费，却没有表现出更高的独立性。当前我国本土所成了“长不大的婴儿”，其内因是我国上市公司缺乏对高独立性审计的自愿性需求。在这种内因和法律责任缺失等因素的作用下，合作所没能提供更佳的审计服务，直...When the audit industry got into a distrusted phase all over the world, CSRC (China Securities Regulatory Commission) enacted a law “No. 16”. The law, which called “Double Auditing System”, arose a lot of controversies. This paper uses the audit fees studying framework of Simunic, via the comparison of audit prices and product differentiation among large-scale native audit firms, small-scale nativ...学位：工商管理硕士院系专业：管理学院工商管理教育中心_工商管理硕士(MBA)学号：19991506

保证我国生态安全的科技战略对策

本文介绍了生态安全问题带给全人类的威胁和中国生态安全面临的主要问题,从三个方面提出了保证我国生态安全的科技战略对策:大力发展绿色科技减少资源和环境破坏,全面依靠科技进步促进生态保护和建设,科学地构建国家生态安全保证体系

卢卡·巴其阿勒及其对世界会计的历史贡献

1994年,世界各国都在隆重纪念“现代会计之父”——luCAPACIOlI(译成中文时,有卢卡·巴其阿勒、卢卡·帕乔利等不同译法)的薄记论发表500周年。500年来,世界会计理论和会计方法有了巨大发展,会计已由一门“艺术”而走向一门“科学”,会计职业也已成为世界上最伟大的职业之一。但所有这些进步和发展,都源于1494年出版的《算术、几何、比及比例概要》一书中的簿记论。本期刊载当代著名会计学家葛家澍教授、郭道扬教授,以及中国第一位会计学博士后研究学者王光远博士所写的纪念文章,以宏扬luCAPACIOlI精神,光大luCAPACIOlI思想,推动中国会计改革

纪念帕乔利复式簿记论建立我国财务会计概念结构

1494年,卢卡·帕乔利的《算术、几何、比及比例概要》在意大利威尼斯城出版发行,这部被史学家誉为集算术、几何、代数、财政数学和会计学于一体的大百科全书,揭开了会计文化的第一页,帕乔利也由此成为会计科学的鼻祖、会计文艺复兴的旗手。500

Understandability of Accounting Information:International Comparison,Influencing Factors and Countermeasures

可理解性是会计信息质量的基本特征之一,各国财务会计概念框架中对“可理解性“这一质量特征的阐述却不尽相同,其原因在于可理解性受到会计信息的固有特征、信息使用者的知识水平和理解能力,以及特定环境因素的影响。尽管如此,几乎所有关于会计信息质量特征的要求中都包括可理解性,fASb和IASb制定的联合概念框架也强调“可理解性“的重要性。在会计准则国际趋同的趋势下,加强对会计信息披露的监管、逐渐减少可供选择的会计处理方法并提供简化年度报告,致力于提高会计信息的透明度,对于各国来说都是积极而务实的选择。Understandability is one of the most basic qualitative characteristics of accounting information(AI).Within the conceptual framework of financial accounting different countries have come up with various interpretations of it,as a result of impacts from such factors as the inherent features of AI,different levels of education and comprehension on the part of information users,and specific environments and contexts.Almost all the requirements about qualitative characteristics of AI include understandability,which is also emphasized in the FASB/IASB Joint Conceptual Framework.This paper argues that,in the context of international convergence of accounting standards,it is constructive and practical for every country to strengthen their regulations on AI disclosure,gradually reduce their alternative accounting methods,and provide simplified annual reports with a view to increasing AI transparency

Synthesis of a Novel TADDOL Type Chiral Ligand with a Binaphthyl Backbone

以3 羟基萘 2 甲酸甲酯4为原料,通过Cu(II)催化的酚氧化偶联、外消旋化合物的拆分和格氏反应等关键步骤,经7步反应以25%的总收率合成了一种具有手性联二萘骨架的新型TADDOL配体12,其光学纯度达到98%.The TADDOLs are a class of chiral ligands which have attracted considerable attention in recent years.They have been widely used in asymmetric synthesis as chiral ligands for a number of asymmetric reactions.The preparation of a novel TADDOL type chiral ligand 3 (Ar=Ph) with a binaphthyl backbone is reported in this paper.The synthesis of this novel ligand started from methyl 3-hydroxy-naphthyl-2-carboxylate 4 by Cu(II) catalyzed oxidative coupling under an oxygen atmosphere.Resolution of the coupled racemic binaphthyl 5 by diastereo-derivatization salt formation followed by basification and acidification afforded the binaphthyl diacid (R)-9 with over 98% ee as determined by optical rotation and compared with the reported data.(R)-9 was converted to its bis-methyl ester (R)-5 by treatment with diazomethane in quantitative yield.The bis-methyl ester was further protected on the phenol hydroxy group by treatment with (chloromethyl)methyl ether (MOM-Cl).Further reaction of (R)-10 with excess phenyl magnesium bromide afforded the tetraphenyl diol (R)-11 in 84% yield.Final removal of the MOM protection by treatment with p-toluenesulfonic acid gave the required ligand (R)-12 in 65% yield.This synthesis was achieved in seven major reaction steps with an overall yield of 25% and the optical purity of ≥98%ee.The application of this ligand for asymmetric reactions will be reported in due course.教育部留学回国人员基金(无编号