The study about IPO earnings management 、short-term change of accounting firms and performance variation

本文以上市公司IPO年度的盈余管理为出发点，旨在探讨不同程度和不同类型的盈余管理是否会对IPO后两年内的会计师事务所变更产生不同的影响，并研究了这些发生了事务所变更的上市公司在IPO后三年的业绩变化情况。 上市公司在IPO过程中普遍存在盈余管理行为，并且成功的盈余管理往往需要会计师事务所的配合。真实盈余管理下公司改变了实质的经营活动，一般不会涉嫌会计处理问题，而需要事务所网开一面甚至是提供决策帮助的，主要是应计盈余管理。 IPO盈余管理行为得到了会计师事务所的纵容甚至是帮助的上市公司，往往在成功上市之后有更换事务所的动机，并且站在事务所的角度，也有不再为其提供审计服务的考虑，因此有不少上市...This paper starts with the phenomenon that most listed companies manage earnings at their IPO years, aiming at probing whether different levels and different kinds of earnings management may have different affects on the change of accounting firms within the subsequent 2 years.Besides,this paper also researches on those companies’s operating performance within 3 three years after their IPO. ...学位：会计硕士院系专业：管理学院_会计硕士学号：1752013115119

Direct Electrochemistry of Hemoglobin on the Electrode Modified with DDAB and SWCNT

使用掺合单壁碳纳米管(SWCNT)的不溶性表面活性剂双十二烷基二甲基溴化铵(DDAB)修饰玻碳电极,并将血红蛋白(Hb)固定在修饰膜中制得了稳定的固载Hb的修饰电极.循环伏安和交流阻抗测试表明,固定在电极上的Hb是一个受吸附控制的可逆电子传递过程.该氧化还原过程的CV扫描峰电位与溶液pH值成良好的线性关系,斜率39 mV/pH,表明在发生Hb直接电子传递反应的同时伴随有质子参与反应.掺合SWCNT的类生物膜修饰电极较之不掺合SWCNT的修饰电极对氧气的还原具有更好的催化作用.并以SWCNT掺合量为1 mg.mL-1的DDAB修饰电极性能最佳.Hemoglobin(Hb) was immobilized onto the surface of glassy carbon electrode with the single-wall carbon nanotubes and surfactant didodecyldimethylamonium bromide(DDAB) modified previously and its electrochemical behaviors have been investigated by cyclic voltammetry.A pair of well-defined redox peaks has been obtained.Cyclic voltammetry and electrochemical impedance spectroscopy(EIS) were also used to study on the effect of different concentration of SWCNT in DDAB.The result shows that the 1 mg/mL is the best choice.The dependence of E0' on solution pH with the slope of 39 mV/pH,indicated that redox of the Hb is a one electron reaction with two protons transfer.The results also showed that the immobilized Hb keeped its electrocatalytic activity toward the reduction of O2.作者联系地址：上海师范大学生命与环境科学学院化学系;Author's Address: Department of Chemistry,Shanghai Normal University,Shanghai 200234,Chin

Direct Electrochemistry of Chloroperoxidase at GC Electrode Modified with SWNTs

将氯过氧化物酶固定到单壁碳纳米管修饰玻碳电极,其循环伏安曲线出现一对准可逆氧化还原峰,说明碳纳米管能够很好地促进氯过氧化物酶在电极表面的直接电子传递.该过程与溶液pH值有关,可指认氯过氧化物酶在电极表面发生的是一电子一质子传递反应.该修饰电极制作简单,性能稳定,且对氧还原具有很好的电催化效应.The chloroperoxidase(CPO) was immobilized onto the surface of SWNTs modified electrodes.The electrochemical behaviors of modified electrode have been investigated by cyclic voltammetry.The appearance of a pair of well-defined redox peaks in the CV curve indicated that SWNTs can promote the electron transfer reaction of CPO.The results of cyclic voltammetry in PBS of different pH,from 3~9,showed that the reaction of CPO on the modified electrode was with equal numbers of electron and protein.This readily prepared SWNTs modified electrode showed excellent stability and good catalysis to O2.作者联系地址：上海师范大学化学系;Author's Address: Department of Chemistry,Shanghai Normal University,Shanghai 200234,Chin