磁光电混合存储在数字档案资源长期保存中的应用研究

［目的／意义］存储载体的选择是数字档案资源长期保存的关键问题，磁光电混合存储是一种集磁存储、光存储和电存储的优点于一体的存储方式，探索其在数字档案资源长期保存中的应用具有较强的理论研究意义和实践指导价值。［方法／过程］通过对当前数字资源和数字档案长期保存研究现状的总结，提出载体选择是数字档案资源长期保存中的重要问题；梳理数字档案资源长期保存载体的相关标准、实践应用、常用载体适用性以及性能需求；介绍并分析磁光电混合存储在数字档案资源长期保存中的优势；以中国科学院档案馆的应用为案例，介绍磁光电混合存储在数字档案资源长期保存中的应用探索。［结果／结论］尽管磁光电混合存储尚存在标准不完善、软硬件仍需改善等不足之处，但其具有绿色节能、总体拥有成本低、存储寿命长、安全可靠、支持多种备份模式等多方面的优势，是符合数字档案资源特性和长期保存需求的最佳选择。</p

剖宫产术后感染相关因素的回顾性分析

目的回顾性分析剖宫产术后感染的相关因素。方法随机抽取行剖宫产的产妇病历347份,以术后感染为结局指标,应用Logistic单因素与多因素分析剖宫产术后感染的独立高危因素,以及不同给药方案(包括给药品种、给药时间、给药时机)对术后感染的影响。结果阴道试产、术中出血量大、产后出血量大以及盆腔粘连是术后感染的独立高危因素(P 24 h组、给药时机为断脐后组与术前组,其术后感染的差异无统计学意义(P> 0. 05)。结论术中出血量大、阴道试产、盆腔粘连等高危因素以及预防性抗菌药物使用与剖宫产术后感染均相关

Degradation of HPAM-containing wastewater with integrated process of UASB and immobilized microorganism reactor

随着聚合物驱油技术在油田的广泛推广,部分水解聚丙烯酰胺(HPAM)在为油田提高采收率的同时,对当地环境也产生了相当大的危害。本文在对含聚污水水质分析和可生化性分析的基础上对污水进行可生化性调整,运用“气浮-uASb-水解酸化-微生物固定化反应器“组合工艺对含聚污水进行了生化处理模拟实验。模拟实验分为静态模拟和动态模拟两部分。静态模拟实验中,降解6天后,聚丙烯酰胺降解率达到89.7%。动态模拟试验中,组合工艺处理2天以后,HPAM降解率为88.65%,原油总去除率为99.40%,出水COd总去除率为93.40%。利用扫描电镜(SEM)和红外光谱分析聚丙烯酰胺降解产物,显示HPAM由大分子物质断裂成小分子物质,HPAM的酰胺基转化为羧基。Polymer flooding technique has become an important method of enhanced oil recovery.But the application of partially hydrolyzed polyacrylamide(HPAM) in oilfield meets many environmental problems.Based on water analysis and biodegradability analysis of HPAM-containing wastewater,improved biodegradability of wastewater was achieved.Laboratory simulation treatment of wastewater was performed by the "flotation-up-flow anaerobic sludge bed(UASB)-hydrolysis acidificationimmobilized microorganism reactor" integrated process.There were two parts in simulation experiment,one was static,and the other was dynamic.After 2 d static biochemical treatment,the degradation ratio of HPAM in wastewater was up to 89.7%.And in dynamic simulation experiment,after 2 d treatment,the degradation ratio of HPAM was up to 88.65%,that of oil was 99.40%,that of COD was 93.40%.HPAM degradation products were analyzed by scanning electron microscopy(SEM) and infrared spectroscopy.The results showed that HPAM was transformed from bigger molecules into smaller molecules and acylamino group in HPAM was transformed into carboxyl group.国家863计划项目(2008AA06Z304

Essays on acquisition of newly listed firms and managerial compensation

This thesis consists of two essays in corporate finance, one on newly listed firms’ post-IPO activities as acquisition targets and the other on corporate executive compensation. In the first essay, I examine a large sample of U.S. newly listed firms to analyze their likelihood of becoming a takeover target. I find that 27 percent of newly listed firms are acquired within five years after the IPO, which is compared with the seasoned-firm counterpart of 17 percent. This difference is economically large, statistically significant, and robust to various firm and market characteristics controls. Several recent studies have reported newly listed firms’ active activities as an acquirer. Contributing to this literature, my finding further identifies an active role of IPO firms as a takeover target. My finding is consistent with the presumed motivation of firms’ going public for a “double-exit” strategy: To sell the shares through a takeover after the company goes public. Economic rationales for this strategy include advantages from auctioning off a minority stake to dispersed shareholders and more efficient bargaining in takeover negotiations due to increased share liquidity and reduced uncertainty after the IPO. Therefore, going public can be an optimal first step in the process of selling a company. In further support of this motivation, I find that IPO firms, as an acquisition target, receive higher takeover premiums than do comparable privately held targets and seasoned target firms. In conclusion, my findings are consistent with the double-exit strategy predicted by theory, suggesting that IPOs facilitate subsequent sales of the companies and that the strategy is economically justified. In the second essay, I study executive compensation under the Japanese corporate governance system. In March 2010, the Japanese regulator enacted the first legislation regarding the disclosure of director compensation to named individuals. With access to the first publicly available data for Japanese executives, I document comprehensive evidence on the level, structure, and mechanisms of CEO compensation. My findings reveal Japanese practices in CEO pay that differ from the well-known Anglo-American model in significant ways. Its distinct features include base salary dominance and unusually low levels of pay and pay variation. I also identify significant impacts on the compensation system of corporate governance and U.S. influence factors, such as keiretsu groups, financial institutions, US-style compensation committees, and cross-listing on US stock exchanges.published_or_final_versionEconomics and FinanceDoctoralDoctor of Philosoph

Synthesis and Application of Carboxyl Functionalized Polystyrene Microspheres

通讯作者：[email protected][中文文摘]采用分散聚合法合成了粒径可控、单分散的聚苯乙烯微球,考察了单体苯乙烯和引发剂偶氮二异丁腈的浓度以及稳定剂聚乙烯基吡咯烷酮的分子量对微球粒径的影响.采用后修饰法对合成的空白微球进行表面羧基功能性修饰,耦联单克隆抗体的免疫测试结果表明微球表面结合探针分子的能力达到国际同类产品水准.[英文文摘]Microsphere-based assay is a powerful platform to carry out biological detection.The carboxyl functionalized,micro-sized polystyrene microsphere is important carrier in the microsphere-based assay.Mono-dispersed polystyrene particles with the size range of 2.0 μm to 7.0 μm were synthesized by dispersion polymerization.The surface of microspheres was carboxyl functionalized by post-modification.It is demonstrated that the functionalized polystyrene microsphere can be well-coupled with monoclonal antibodies with comparable performance achieved as that of commercial carboxyl polystyrene microspheres (Spherotech Inc.).国家基础科学人才培养基金(J0630429);2007年度教育部新世纪优秀人才支持计划;教育部留学回国人员科研启动基金;2006年度福建省新世纪优秀人才支持计划资

云南杨梅碳、氮、磷化学计量特征

碳(C)、氮(N)、磷(P)在植物生长和各种生理调节机能中发挥着重要作用。为研究云南灌丛生态系统C、N、P含量之间的关系以及植物生物量、土壤C、N、P含量与植物C、N、P含量的相互影响,该研究采用样地调查的方法,在云南省云南杨梅(Myrica nana)灌丛主要分布区设立了29个样地,通过测量样地中云南杨梅灌丛C、N、P含量,系统分析了云南杨梅C、N、P的计量规律。结果显示:1)研究区域云南杨梅根、茎、叶的C、N、P含量的平均值分别是45.94%、0.54%、0.03%,46.32%、0.58%、0.03%和49.05%、1.70%、0.06%(干质量),其中叶的C、N、P含量均显著高于茎和根。在根中C:N:P为1 531:18:1,在茎中C:N:P为1 544:19:1,而在叶中C:N:P为818:10:1,反映了云南杨梅不同部位元素计量不同的分配关系;2)云南杨梅叶片中C含量和N:P值随生物量的增加而降低,但只有叶片C含量与生物量的相关关系极显著,而N:P值与生物量的相关关系不显著。叶片中N含量和P含量随生物量的增加而升高,其中P含量与生物量的相关关系显著,N含量与生物量的相关关系不显著。云南杨梅叶的N:P(34.2)明显大于8,说明P是云南杨梅生长的限制因素。3)根的C、N、P含量与土壤中的P含量都有显著的相关性,其中N、P为极显著正相关,C为显著负相关;茎的C含量与土壤的C、N、P含量都显著负相关,且N、P含量的相关性极显著,而茎的P含量与土壤中的P含量极显著正相关;叶的P含量与土壤的C、N、P含量都极显著正相关,叶的C含量则与土壤的P含量极显著负相关。该研究结果可为西南高原灌丛生态系统的研究提供数据支持

Influence of Electrode Hydrophobicity on Performance of Alkaline Polymer Electrolyte Fuel Cells

本文报道H2-O2型碱性聚合物电解质燃料电池（APEFC）电极疏水性对放电性能的影响. 以季铵化聚砜（QAPS）或自交联型季铵化聚砜（xQAPS）碱性聚电解质（APE）作为隔膜和电极中的电解质（Ionomer）、聚四氟乙烯（PTFE）作为疏水添加剂调控催化层疏水性. 结果表明，阳极催化层疏水性的增强有利于提升电池放电性能，而阴极催化层疏水性适中时电池性能最优. 采用疏水性较强的xQAPS作为电解质并在阳极催化层中添加适量PTFE疏水剂，在60 oC和100%相对湿度的条件下，280 mA&middot;cm-2电流密度时，电池最高功率密度达132 mW&middot;cm-2.In the present work, we study the influence of the electrode hydrophobicity on the performance of alkaline polymer electrolyte fuel cells (APEFCs). QAPS or xQAPS is employed as the membrane and the ionomer, while PTFE is used as a hydrophobic additive in order to adjust the electrode hydrophobicity. We find that enhancing the hydrophobicity of anode can promote the performance of APEFCs, while a moderate hydrophobicity of cathode is required to achieve optimal performance. By using xQAPS as the electrolyte and adding some PTFE in the anode, a peak power density of 132 mW&middot;cm-2 can be obtained at a current density of 280 mA&middot;cm-2 when the APEFC single cell is operated under 100% RH at 60 &ordm;C.国家重点基础研究发展计划（No. 2012CB932800，No. 2012CB215500）、国家高技术研究发展计划（No. 2011AA050705）和国家自然科学基金（No. 20933004，No. 21125312）资助作者联系地址：武汉大学 化学电源材料与技术湖北省重点实验室，化学与分子科学学院，湖北 武汉 430072Author's Address: College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China通讯作者E-mail：[email protected]; [email protected]