阳离子调节光能在两个光系统之间分配的研究--PQ和光能分配的关系的探讨

本文报告了以下几点研究结果： 1．类囊体膜经非性有机溶剂正已烷抽提后，其Mg2+调节能量分配的效率下降;加入人工合成的PQ类似物如PQ2后Mg2+调节能量分配的效率可得到部分恢复。 2．对类囊体膜进行外电场电泳迁移率测定的结果表明，加入PQ2并不影响类囊体膜的表面净电荷密度。 3．应用PQ的竞争性抑制剂DBMIB的试验证明，DBMIB抑制Mg2+和Ca2+调节能量分配的效率，但不影响类囊体膜的表面净电荷密度。 4．在正已烷抽提过的类囊体中加入PQ2或在新鲜类囊体中加入DBMIB对类囊体膜的吸收光谱没有影响。PQ2和DBMIB可能对类囊体膜的粗结构影响不大。 5．类囊体膜处于等电点时，其表面净电荷密度不受Mg2+或Ca2+的影响（在我们所用的浓度范围内）。但在等电点下，仍能观察到Mg2+或Ca2+调节能量分配的效应。 根据实验结果，我们认为：阳离子对光能在两个系统之间分配的调节作用可能是通过两种不同机制进行的：其中之一与类囊体膜表面净电荷密度变化有关，另一种则与类囊体膜表面净电荷密度变化无关，而后者可能和PQ的活性和状态有关。

Gas properties as a limit to gas turbine performance

Although increasing the turbine inlet temperature has traditionally proved the surest way to increase cycle efficiency, recent work suggests that the performance of future gas turbines may be limited by increased cooling flows and losses. Another limiting scenario concerns the effect on cycle performance of real gas properties at high temperatures. Cycle calculations of uncooled gas turbines show that when gas properties are modelled accurately, the variation of cycle efficiency with turbine inlet temperature at constant pressure ratio exhibits a maximum at temperatures well below the stoichiometric limit. Furthermore, the temperature at the maximum decreases with increasing compressor and turbine polytropic efficiency. This behaviour is examined in the context of a two-component model of the working fluid. The dominant influences come from the change of composition of the combustion products with varying air/fuel ratio (particularly the contribution from the water vapour) together with the temperature variation of the specific heat capacity of air. There are implications for future industrial development programmes, particularly in the context of advanced mixed gas-steam cycles.

新型硅基蓝-紫光发光材料

本实用新型步及一种新型硅基蓝－紫光发光材料，该发光材料是在单晶硅基片层上设有发光层，在发光层上设有薄膜保护层；本实用新型的性能稳定且发光效率较高，另本实用新型可发出蓝－紫光。

An anionic antimicrobial peptide from toad Bombina maxima

Amphibian skin is a rich resource of antimicrobial peptides like maximins and maximins H from toad Bombina maxima. A novel cDNA clone encoding a precursor protein that comprises maximin 3 and a novel peptide. named maximin H5. was isolated from a skin cDNA library of B. maxima. The predicted primary structure of maximin H5 is ILGPVLGLVSDTLDDVLGIL-NH2,. Containing three aspartate residues and no basic amino acid residues. maximin H5 is characterized by an anionic property. Different from cationic maximin H peptides. only Gram-positive strain Staphylococcus aureus was sensitive to maximin H5. while the other bacteria] and fungal strains tested ere resistant to it. The presence of metal ions. like Zn2+ and Mg2+, did not increase its antimicrobial potency. Maximin H5 represents the first example of potential anionic antimicrobial peptides from amphibians, The results provide the first evidence that. together kith cationic antimicrobial peptides. anionic antimicrobial peptides may also exist naturally as part of the innate defense system. (C), 2002 Elsevier Science (USA). All rights reserved.

Study on the critical submergence of surface vortices and the design of anti-vortex intakes

Surface vortex behavior in front of the tunnel intake was investigated in this paper. The critical submergence of vortex was discussed based on the concept of 'critical spherical sink surface' (CSSS). The vortex formation and evolution at the tunnel intake were analyzed based on the theory of CSSS considering the effect of circulation. A theory was proposed to explain the surface vortex. The theoretical development was verified by the physical model experiments of Xiluodu hydropower station. The radial velocity and vortex circulation were considered as the main factors that influence the formation and evolution of surface vortex. Finally, an anti-vortex intake configuration was proposed to weaken the air-core vortex in front of the tunnel intakes of the hydraulic structures. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Differential population structuring and demographic history of two closely related fish species, Japanese sea bass (Lateolabrax japonicus) and spotted sea bass (Lateolabrax maculatus) in Northwestern Pacific

The Quaternary cold periods in the Northwestern Pacific are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in marine fishes. To estimate the demographic history and genetic structure of Lateolabrax macula

Mitochondrial control region and population genetic patterns of Nycticebus bengalensis and N-Pygmaeus

Bengal slow lorises (Nycticebus bengalensis) and pygmy slow lorises (Nycticebus pygmaeus) are nocturnal which creates difficulties to study them in the field. There is a scarcity of data on them and their population genetics are poorly understood. We sequ

鱼腥藻对氧敏感的固氮突变种

<正> 柱孢鱼腥藻(Anabaena cylindrica)和鱼腥藻7120(Anabaena 7120)(均为蓝藻植物)在空气中均能固定分子态氮.我们用紫外线和亚硝基胍分别对它们进行诱变、筛选,获得二株具异形胞而不能在空气中固定分子态氮的突变种.鱼腥藻-1(Anabaena-1)是鱼腥藻7120经紫外线诱变后得到的突变种,而鱼腥藻-2(Anabaena-2)是柱孢鱼腥藻经NTG诱变后获得的突变种.它们的异形胞频率(10～17.5%)高于野生种(5～9%).经二年多的连续传代培养表明突变表型是稳定的,自发