论上市公司盈利的信息含量

在中国股票市场上 ,不仅未预期盈余具有信息含量 ,从各别年份来看 ,利润率的高低也会影响股票价格 ,因而 ,利润率本身也具有信息含量。在 1996年高利润率是利好消息 ,但到了 1998年却成了利差消息。 1997年回归结果表明 ,政府的干预和证监会加强监管对证券市场的规范起了重要的作用 ,证券管理部门对证券市场的管理应持之以恒 ,不能搞传统的一阵风的短期行为。尽管上市公司利润操纵现象较为普遍 ,个别公司影响恶劣 ,但投资者仍然以上市公司发布的财务信息为依据进行投资决策 ,这种情况下财务信息披露的规范显得尤为重要与急迫

Synthesis of high-index faceted Pt nanocrystals supported on carbon black and investigation of their electrocatalytic property

负载到碳基底上的铂族金属纳米粒子是直接醇类燃料电池(DAFC)难以替代的催化剂。以单晶面为模型催化剂的基础研究指出铂族金属高指数晶面由于含有高密度的台阶原子和扭结原子，其催化活性和稳定性明显优于{111}、{100}等低指数晶面。但是，由于高指数晶面具有很高的表面能，一般的方法很难制备由高指数晶面围成的铂纳米催化剂。 本论文运用我们研究组发展的金属纳米晶体表面结构控制和生长的电化学方波电位法，通过优化制备条件，以VulcanXC-72碳黑为载体制备了小粒径(与商业催化剂相当)、具有高指数晶面结构的Pt/C纳米晶催化剂（HIF-Pt/C）。此外，我们还初步探索了高指数晶面结构的Rh纳米晶体的制...Platinum-group metal nanoparticles supported on carbon are the irreplaceable catalysts in direct alcohol fuel cells (DAFC). Fundamental studies of single-crystal model catalysts have demonstrated that high-index faceted platinum-group nanocrystals with high density of atomic steps and kinks usually exhibit much higher catalytic reactivity and stability than those of low-index {111} and {100} facet...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：2052006115196

从会计本质看会计目标与会计职能

从会计本质看会计目标与会计职能●黄志忠对会计的职能与目标的界定，关系到会计能输出什么信息和应输出什么信息的问题，这恰恰是会计应解决的根本问题。因此，对这个问题的讨论是很有意义的。贵刊1995年11期、1996年第6期分别刊载了刘峰的文章《会计目标与职..

后危机时代福建外经贸的转型与发展

在由美国次贷危机所引发的全球金融危机中,福建省的对外经济贸易经受了严峻的考验,同时也暴露出一些不足。因此,在后危机时期,重新审视福建外贸发展的现状与存在的问题,分析后危机时期福建外经贸发展的新形势,探讨后危机时期福建外贸发展的思路与对策,不仅很有必要,而且意义重大

海洋浮游生物电子传递系统研究进展

国家自然科学基金!49636220;4977630

Studies on the Interactions between Bioactive Peroxovanadium Complexes Bearing Organic Ligands and Histidine

在合成和表征了 4种具有较强生物活性双过氧钒配合物K3 [VO(O2 ) 2 (ox) ]·2H2 O ,Na[VO(O2 ) 2 (bipy) ]·5H2 O ,K[VO(O2 ) 2 (phen) ]·3H2 O和K2 [VO(O2 ) 2 (pic) ]·2H2 O [分别缩写为pV(ox) ,pV(bipy) ,pV(phen)和pV(pic) ,其中ox为草酸根 ,bipy为 2 ,2′ 联吡啶 ,phen为邻菲咯啉 ,pic为 2 羧酸吡啶负离子 ]的基础上 ,利用多种NMR技术和电喷雾质谱 (ESI MS)研究了这 4种含有机配体双过氧钒配合物与组氨酸 (His)在溶液中的相互作用以及反应物浓度、时间、pH等对相互作用体系的影响 .51VNMR跟踪监测的结果表明 :双过氧钒配合物pV(ox)和pV(pic)与His在中性水溶液中存在强配位相互作用 ,而pV(bipy)和pV(phen)与His在中性水溶液中无明显作用 .我们还利用谱学方法确定了pV(ox)和His相互作用后所生成产物是pV(ox)分别与His咪唑基上的 3 N和 1 N配位的一对异构体. 　In order to explore the structure2activity relationship and molecular mechanism of the specific recognition between peroxovanadium (pV) complexes bearing organic ligands and the target enzymes of tyrosine phosphatase , several NMR techniques and ESI2MS were used to study the interactions of four pV complexes {pV(ox) , pV ( bipy) , pV (phen) and pV (pic) , where pV = [VO (O2 ) 2L ] n - , in which L = oxalic acid dianion (ox) , bipyridine (bipy) , 1 ,102phenanthroline (phen) , and pyridine222carboxylic acid (pic) } towards histidine. Strong coordination interactions between imidazole of histidine and vanadium of pV(ox) or pV(pic) were observed in neutral solution , while there are not obvious interactions between histidine and pV(bipy) or pV(phen) . All 13C and 1H NMR signals of 1∶1 stoichiometric mixture of pV(ox) and histidine were assigned. Spectroscopic studies demonstrated that new complexes in the mixture of pV(ox) and histidine are a pair of isomers in which the vanadium in pV(ox) binding to the 32N and 12N of the imidazole ring. Moreover , the results of effective factors on the interaction system indicated that the new isomers were stable under the condition of physiological pH and the structure2activity relationship of these pV complexes may be relevant to their specific recognition towards histidine residues in tyrosine phosphatase.国家自然科学基金 (Nos.2 0 172 0 42 ,2 9832 0 2 0 )资助项

倏逝场作用氧化石墨烯大能量耗散孤子锁模双包层光纤激光器

报道了倏逝场作用氧化石墨烯的可饱和吸收体用于锁模掺镱双包层光纤激光器,产生大能量151.54nJ耗散孤子.利用熔锥光纤倏逝场诱导沉积氧化石墨烯方法,所制备的可饱和吸收体不仅拥有耐高功率、光纤兼容等优点;而且,熔锥光纤引入光带通滤波,有益于耗散孤子在光纤激光腔中形成.同时结合光纤包层泵浦技术,高脉冲能量耗散孤子在锁模掺镱双包层光纤激光器中被获得,产生的耗散孤子单脉冲能量高达151.54nJ,重复频率271.4kHz,信噪比57dB.国家自然科学基金(61275050);高等学校博士学科点专项科研基金(20120121110034

LBO的腔内倍频特性研究

从倍频转换效率公式和腔内倍频的稳定态条件出发,得到倍频波的功率密度公式,进而得出倍频晶体最佳长度和倍频波最大功率密度的表达式。以LBO晶体Ⅰ类临界相位匹配腔内倍频946 nm为例,根据倍频波的功率密度公式,从理论上讨论了LBO长度、功率密度比对倍频波功率密度的影响,为LBO倍频产生473 nm蓝光实验提供了理论指导。虽然这里只是讨论了LBOⅠ类临界相位匹配倍频946 nm,但对所有腔内倍频实验(不同倍频晶体或不同倍频频率)具有借鉴作用

Studies on the interactions between bioactive peroxovanadium complexes bearing organic ligands and histidine

In order to explore the structure-activity relationship and molecular mechanism of the specific recognition between peroxovanadium. (pV) complexes bearing organic ligands and the target enzymes of tyrosine phosphatase, several NMR techniques and ESI-MS were used to study the interactions of four pV complexes {pV(ox), pV(bipy), pV(phen) and pV(pic), where pV=[VO(O-2)(2)L](n-), in which L=oxalic acid dianion (ox), bipyridine (bipy), 1, 10-phenanthroline (phen), and pyridine-2-carboxylic acid (pic)} towards histidine, Strong coordination interactions between imidazole of histidine and vanadium of pV(ox) or pV(pic) were observed in neutral solution, while there are not obvious interactions between histidine and pV(bipy) or pV (phen). All C-13 and H-1 NMR signals of 1:1 stoichiometric mixture of pV (ox) and histidine were assigned. Spectroscopic studies demonstrated that new complexes in the mixture of pV (ox) and histidine are a pair of isomers in which the vanadium in pV(ox) binding to the 3-N and 1-N of the imidazole ring. Moreover, the results of effective factors on the interaction system indicated that the new isomers were stable under the condition of physiological pH and the structure-activity relationship of these pV complexes may be relevant to their specific recognition towards histidine residues in tyrosine phosphatase