242 research outputs found
Studies on the Effects of Supports and Metal Nanoparticle Sizes of Supported Catalysts for Asymmetric Hydrogenation of Aromatic Ketones and Hydrogenolysis of Sorbitol
潜手性底物的不对称加氢反应是获得高纯度手性化合物的重要手段之一。以芳香酮不对称加氢反应为例,Noyori等开发的[(R)-BINAP-Ru-(1R,2R)-DPEN]Cl2均相催化剂具有很高的催化活性和产物对映选择性,但是均相体系产物分离和催化剂循环使用困难,而均相催化剂的多相化是解决该矛盾的有效途径之一。 山梨醇是生物质开发过程12个重要平台分子之一,工业上可以通过葡萄糖加氢反应大量生产。其氢解产物乙二醇和丙二醇都是重要的化工原料,传统的生产工艺为烯烃先环氧化再水合的方法。生物质途径制备二元醇是石油化工途径的替代方法之一。目前,工业上应用的氢解催化剂多为贵金属催化剂,因此研发廉价、高效、可...Asymmetric hydrogenation of prochiral substrates is one of the effective methods to obtain high enantioselective compounds. The [(R)-BINAP-Ru-(1R,2R)-DPEN]Cl2 catalyst developed by Noyori was demonstrated as one of the effective homogeneous catalysts for the asymmetric hydrogenation of aromatic ketones. It exhibited not only excellent activity but also high ee value. However, the separation and re...学位:理学博士院系专业:化学化工学院化学系_物理化学(含化学物理)学号:1912005140308
金融资产管理公司对不良资产处置评估问题探析
本文在分析金融不良资产特点的基础上,对现有的几种不良资产处置评估方法作了深入的分析研究,探讨了金融资产管理公司在各种不同的不良资产处置方式下,各种评估方法的适用性,以增强评估过程的科学性和评估结果的准确性
An Analysis Of The Appraisal Issues In The Disposal Of Non-performing Financial Assets Held By AMC
1999年金融资产管理公司成立以后,我国确立了金融不良资产市场化处置的基本思路,面对我国不良资产处置的现实需要,以及目前我国现实的不良资产处置外部环境的制约,不良资产处置评估这一新领域中出现了诸多理论和实践问题。本文试图通过对当前我国金融资产管理公司不良资产处置评估过程中相关方面的经验总结及对存在的问题进行分析,探索完善不良资产处置评估的新的思路和方法,以期提高评估过程的科学性和评估结果的有效性。 本文的主体部分共分四章 第二章在明确界定金融不良资产概念边界的基础上,首先分析了金融资产管理公司所持有的金融不良资产的特点;其次探讨了金融不良资产的制度性成因及其主要的存在形式,并进一步分析了不...Non-performing assets have maintained a high proportion in the state-owned banks due to historical and institutional causes. In order to solve the large volume of non-performing assets that might lead to financial crisis and achieve the goal of optimizing bad asset recovery through the disposition by a special organization, the four financial assets management companies(AMC) were established whic...学位:经济学硕士院系专业:经济学院财政金融系_财政学(含税收学)学号:20011200
Study on Unoccupied Property Embezzlement
侵占脱离占有物罪是域外刑事法律中的一个罪名,是在对广义的侵占罪进行细分的基础上得到的、不同于委托物侵占罪的罪种。我国刑法第270条的两个条款统称为侵占罪。该条第2款规定遗忘物、埋藏物的侵占,类似于域外侵占脱离占有物罪的规定。但相比较域外立法,该条款在犯罪对象、法定刑设置等处存在一些不同。事实上,就第270条第2款的犯罪对象,以及该条款与该条第1款之间的关系等问题,我国刑法学界存在诸多争议。本文立足于我国刑法第270条第2款的规定,借鉴域外地区立法及学理论述,分析侵占脱离占有物罪的构成要件,提出对该条款规定的修订意见。本文意义在于,通过本文的分析和论述,区分普通的侵占罪和侵占脱离占有物罪,以科学...Unoccupied property Embezzlement is a crime in extraterritorial criminal law. It comes from subdivision of Embezzlement, which is different from entrusted property Embezzlement. Embezzlement is provided in Article 270 in Criminal Law of the People's Republic of China, and the Article contains two paragraphs, which are all called Embezzlement. Between this two, Paragraph 2 provides occupying lost p...学位:法学硕士院系专业:法学院法律系_刑法学学号:2005130038
Effects of Salinity and Waterlogging on Seedling Growth of Mangrove Heritiera littoralis
采用盆栽试验,探讨盐度和水渍对2月龄红树植物银叶树生长的影响。结果表明,银叶树幼苗的耐盐临界值在25‰左右,低于25‰的中低盐度,有利于其幼苗的生长和生物量累积,而高于25‰的高盐度环境,将抑制甚至威胁银叶树幼苗的生存。盐度和水渍对银叶树幼苗生长有联合影响:水渍对于高盐度下的银叶树幼苗有快速致死的作用,而对中低盐度的幼苗并未有显著影响。研究结果表明:要避免将其幼苗种植在高盐度区域,并避免在较低潮位的海滩种植。Potted plant experiments were used to investigate the effects of salinity on growth parameters of H.littoralis seedlings.Results showed that 25‰ salinity approached the limit of salt tolerance for seedlings.Salinity below 25‰ was conductive to its growth and biomass accumulation,and salinity beyond 25‰ would inhibit its growth or even threaten its survival.Combined effects of salinity and waterlogging were also examined on these seedlings.Waterlogging rapidly resulted in seedlings' death under high salinity,but if salinity was low to mediate,there were not differences in growth rates between different salinities.The research suggested this species cannot be replanted in coastal intertidal zones with high salinity and low tide level.国家自然科学基金项目(41276077
X波段阶梯阻抗微带带通滤波器设计
设计了一款X波段的多模带通滤波器,并给出了仿真与实验结果。采用恒定阻抗枝节加载3个阶梯阻抗枝节的方式,构成滤波器的主体;利用表面电流分布图获得影响带内极点分布的枝节参数,通过调整阶梯阻抗枝节参数优化滤波性能。为实现更好的带外抑制能力,滤波器两端各串联一对平行耦合线,在14 GHz引入一个传输零点。实验测试结果显示,所设计滤波器的中心频率为9.76 GHz,带宽为2.4 GHz,30 dB/3 dB矩形系数为1.63,相对带宽为25%,带内插入损耗大部分小于1 dB,大部分回波损耗高于15 dB,与仿真结果较为吻合。国家自然科学基金资助项目(61601393);;福建省自然科学基金资助项目(2016J01321);;极高频复杂系统国防重点学科实验室开发基金资助项
电子商务环境下制造商与零售企业广告合作研究
电子商务环境下零售企业合作广告问题研究是通过改进前人关于地方性广告对市场影响的假设模型,用非线性函数替代传统模型中的固定增量,以接近市场的真实博弈情境;通过对上下游零售企业与制造商双方边际利润与产品价格弹性系数等相关经济参数的计算,分析各因素对参与方产生的影响并对部分结论进行实证分析
Study on Nitrification Behavior of Aerated Biofilter with Oyster Shell Carrier
贝壳粗糙的表面及其含有的大量碳酸钙,可作为生物膜的载体及硝化反应的碱度来源。以海产弃物贝壳为生物膜载体,通过改变进水氨氮浓度及pH值,考察了贝壳填料曝气生物滤池的硝化脱氮规律。结果表明:对于氨氮<120 mg/L的原水,贝壳溶解提供的碱度能够满足硝化反应的需要,因此硝化反应进行得比较完全,对氨氮的去除率不受进水氨氮浓度的影响,可达90%以上;而当进水氨氮浓度达240 mg/L时,因贝壳溶解提供的碱度不能完全满足硝化反应之所需,硝化反应将停滞,但对氨氮的去除率仍可达65%左右。此外,进水pH值对贝壳填料曝气生物滤池去除氨氮的效果及出水pH值基本没有影响。Oyster shell contains a large amount of CaCO_3, which supplies the alkalinity source for biological nitrification process.The nitrification behaviors in aerated biofilter with oyster shell as biofilm carrier were investigated under different ammonia concentrations and pH values.The results indicate that the biofilter with oyster shell carrier shows better nitrification performance.Without additional alkalinity supply,the ammonia removal efficiency in the biofilter can reach more than 90% when influent ammonia concentration is not above 120 mg/L.However,when the influent ammonia concentration increases to 240 mg/L,ammonia removal efficiency decreases to 65% due to the limitation of alkalinity supply from shell for nitrification need.The influent pH value does not affect the nitrification efficiency and effluent pH value.福建省自然科学基金资助项目(DO210004
- …
