Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Chiral Multidentate Aminophosphine Ligands/Iron Cluster

从廉价易得、绿色环保的铁簇合物Fe_3(CO)_(12)出发,开展了其与手性多齿胺膦配体(R,R,R,R)-PN_4H_6原位生成的催化体系在酮; 的不对称转移氢化中的应用研究.通过考察温度、添加剂等影响因素,探索最优的反应条件,并将其进一步应用于多种芳香酮的不对称转移氢化反应,得到高达96; % ee的对映选择性.As one of the most abundant metals on earth, iron is cheap and low toxicity. Herein we reported the asymmetric transfer hydrogenation of (ATH) ketones catalyzed by the system generated in situ from chiral multidentate aminophosphine ligand (R, R, R, R)-PN4H6 and Fe-3(CO)(12). The effects of temperature and additive on the ATH of propiophenone were examined. After optimizing the reaction conditions, we applied the catalytic system to the ATH of various aromatic ketones, obtaining the corresponding optical active alcohols with high enantioselectivities (up to 96% ee).National Natural Science Foundation of China [21173176, 21673190];; Fundamental Research Funds for the Central Universities [20720150040

基于系统可靠性的主动配电网置信容量评估

评估主动配电网的置信容量,可以充分利用新能源,为主动配电网的优化配置提供有效参考。以新增电源的有效载荷能力表征主动配电网的置信容量,建立基于等可靠性指标的评估模型。在蒙特卡..

内控质量与公司绩效:基于内部代理和信号传递理论的视角

本文根据内部代理理论,构建了公司内部治理机制——高质量内部控制提升公司绩效的理论框架。基于中国2007—2012年自愿进行内部控制审计的样本及控制样本,用无保留内部控制审计意见代表高质量内部控制,本文研究发现,内部控制质量高的公司与内部控制质量低的公司相比,尽管其财务绩效没有更好,但其市场绩效更好;并且,无保留内部控制审计意见针对财务报告内部控制,与无保留内部控制审计意见针对公司整体内部控制相比,其财务绩效无差异,但其市场绩效更好。进一步研究发现,高质量的内部控制尽管没有改善公司的财务绩效,但通过降低公司的内部代理成本、财务风险和市场风险向市场传递了好消息,间接提升了公司的市场绩效。本研究首次基于内部代理理论和信号传递理论探讨作为一种公司内部治理机制的内部控制如何作用于公司绩效。国家自然科学基金项目(71002045、71172054、71372075、71473211); 福建省社科项目(2011B211); 福建省高校新世纪优秀人才支持计划的资

基于并行小种群差分进化算法的水火电力系统短期优化调度

为解决水火电力系统短期发电优化调度中存在的问题,提出基于MPI平台的并行小种群差分进化算法。该算法将进化种群分为若干个小种群(单个种群规模为3~10个),每个进化种群由不同的CPU进程独立执行差分进化算法,并在种群间引入集合、分散操作以协调各小种群的寻优过程;为降低小种群初始化和进化过程中多样性的损失,引入正交化初始化方法和种群重构技术;最后以典型案例验证了算法的有效性。结果表明,该方法在求解精度、收敛速度和求解耗时上均较有竞争力。国家自然科学基金项目(61403321);;广东省自然科学基金项目(2014A030310003

Forward Osmosis Membrane Principle and Its Application Were Reviewed

正向渗透是一项新型的利用半透膜两侧溶液渗透压差作为驱动力的膜分离技术。文章介绍了正向渗透膜分离技术的原理和影响因素,对其在各个领域(包括海水淡化、废水处理、橙汁浓缩、水袋)的研究进展进行了综述。现有的研究表明,可用于正向渗透工艺的膜不同于常规的反渗透膜,需要从膜结构开发适合的膜组件;采用nH3和CO2制备提取液是目前研究中具有应用前途的方式之一,具有产水率高且易于分离浓缩的优点。Forward osmosis(FO) is a novel membrane separation technique which utilizes osmotic pressure differential as the driving force and themechanism features of forward osmosis process are introduced.The research progress in seawater desalination,orange juice concentrate,wastewater treatment,water bag is also reviewed.The research shows that FO membrane is different from RO membrane.Appropriate FO membrane should be developed by consideration of the membrane structure.The processing ammonia and carbon dioxide to prepare draw solution is one of the most promising processes,because of the high water flux and being easily separated

Regulation effect of exogenous nitric oxide on anti-oxidation system of Kandelia candel seedlings treated with NaCl

研究了外源一氧化氮(NO)供体硝普钠(SNP)对NaCl处理下红树植物秋茄(Kan-deliacandel)幼苗叶片中抗氧化酶活性、抗氧化物质及脯氨酸含量的影响。结果表明:NaCl处理下,秋茄幼苗叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)等4种活性氧清除酶的活性均受到明显抑制(P<0.05),SNP可以不同程度地恢复SOD、POD、CAT的活性,但对APX活性影响不大;SNP提高谷胱甘肽(GSH)及类胡萝卜素(Car)的含量,促进脯氨酸含量的上升,显著降低叶片中过氧化氢(H2O2)和丙二醛(MDA)的累积。表明外源NO可以缓解NaCl处理诱导的秋茄幼苗叶片氧化损伤,降低膜脂过氧化水平,有利于秋茄适应盐生环境。By using sodium nitroprusside(SNP)as the donor of exogenous nitric oxide,this paper studied its effects on the antioxidant enzyme activities,anti-oxidation substances,and proline content in the leaves of Kandelia candel seedlings treated with NaCl.The results showed that after treated with NaCl,the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and ascorbate peroxidase(APX)in K.candel seedling leaves were depressed significantly(P<0.05),while SNP could recover the activities of SOD,POD and CAT to different degrees but showed little effect on APX.SNP increased the contents of glutathione(GSH)and carotenoid(Car),promoted the production of proline,and decreased the accumulation of H2O2 and malondialdehyde(MDA)significantly.It was indicated that SNP could relieve the oxidation damages induced by NaCl via decreasing the level of membrane lipid peroxidation in K.candel leaves,and facilitate K.candel to adapt to saline environment.国家自然科学基金项目(30670317和39970438);; 厦门大学新世纪优秀人才支持计划项目(0000-X07115)资

宝黛相争 谁伴宝玉欧洲游?

部门经理应当如何处理公与私的矛盾?领导面对复杂的人际关系,应该采取何种处事原则?家族企业中的空降CEO,如何应对各种人事矛盾避免引火烧身

Accrual Reliability,Earnings Persistence and their Capital Market Reactions

本文将资产负债项目的可靠性和盈余的持续性相联系,并探讨资本市场能否解读这种联系。首先,理论分析表明可靠性更差的资产负债项目导致盈余的持续性更低。其次对应计项目进行分类并评价其可靠性。最后,证据表明,更不可靠的应计项目导致盈余的持续性更低,并且资本市场没有充分预期到这种联系从而作出错误反应。这些结果说明,在财务报表中确认可靠性更低的应计项目会导致更大的成本,相关性的获得不应以牺牲可靠性为代价。This essay links accrual reliability to earnings persistence,and explores whether the capital market can read these linkages.First,we establish a model aiming to indicate that less reliable accruals lead to lower earnings persistence.Second,we carry out a complete balance sheet classification of accruals,and rate each based on the reliability of the respective accruals.Last,evidence shows that less reliable accruals lead to lower earnings persistence and that investors do not fully expect this lower earnings persistence.Accordingly,there are substantial costs associated with recognizing less reliable accruals in financial statements,and we should not achieve relevance at the expense of reliability.教育部人文社会科学重点研究基地资金资助,项目批准号06JJD63001

The Study of Chlorella vulgaris Harvesting Using Foam Separation

考察了泡沫分离法采收小球藻的可行性,研究了不同表面活性剂、表面活性剂用量、藻液PH值、藻液原液体积、分离气速等因素对泡沫分离法采收小球藻的影响.结果表明,在本实验中构建的泡沫分离装置条件下采用泡沫分离法收集小球藻时,以十六烷基三甲基溴化铵为表面活性剂,且在其用量为0.25g/l、藻液PH为11、分离原液体积为200Ml和分离气体流速为70Ml/MIn时,富集比和分离率相对较高,富集比和分离率分别为8.39和99%,小球藻的泡沫分离收集效果最好.The Chlorella vulgaris harvesting using foam separation was studied in this work.The optimum surfactant and the optimum concentration of surfactants were investigated,as well as the optimum pH,volume of algae culture and the gas velocity.The results showed that the cetyl trimethyl ammonium bromide was the best surfactant in the study and the optimum surfactant concentration was 0.25g/L.Additionally,the optimum volume of algae culture was 200 mL,the optimum pH was 11 and the gas velocity was70mL/min,under which the higher enrichment ratio and the isolation rate were up to 8.39 and 99%,respectively.国家自然科学基金(21406185); 福建省科技计划重点项目(2013H0043