基础教育课程改革背景下的公民教育课程探微——公民教育社区服务活动课程概述

在基础教育课程改革背景下,学校公民教育课程化成为公民教育理论和实践界的焦点。本文初步阐述了适合于我国基础教育改革背景的公民教育课程之一——公民教育社区服务活动课程——的性质,特点,内容和实施等问题。     

基于嵌入式系统的听觉与时间知觉测试仪

依据实验心理学对听觉测试与时间知觉测试的要求,设计开发了一种以嵌入式微控制器LPC2214为硬件核心,以实时操作系统μC/OS-Ⅱ为软件开发平台的"听觉与时间知觉测试仪".在此基础上,实现了测试仪的硬件电路和软件程序,并完成了仪器的原理样机调试.     

Effect of Mn cluster on the formation of superoxide radicals in photoinhibition of photosystem Ⅱ

To further realize the action of superoxide radicals (O₂^{− .}) in photoinhibition of photosystem Ⅱ (PSⅡ), we employed 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap, associated with EPR spectroscopy, to study the effect of illumination time on O₂^{− .} formation during high light photoinhibition in PSⅡ membranes and Mn-depleted PSⅡ membranes. Results indicated that the removal of Mn cluster from PS
membranes has a strong influence on the dynamics of superoxide formation. The relative mechanism was also discussed. These novel findings may further promote the studies of the structure and function of PSⅡ and the mechanism of photoinhibition.     

Pedogenesis affecting the Matuyama-Brunhes polarity transition recorded in Chinese loess?

A detailed record of the Matuyama-Brunhes (M-B) transition has been obtained from the loess unit 8 (L8) at Duanjiapo (34.2°N, 109.2°E),Shannxi Province of China. An investigation of the rock magnetic properties using hysteresis loops, thermomagnetic analyses identifies pseudo- single domain magnetite as the main carrier of the remanence, with a small contribution from maghemite and hematite. The paleo-direction records obtained reveal: (ⅰ) The M-B transition was recorded in the middle and lower part of L8, and comprises of five fast reversals. (ⅱ) The duration of the M-B polarity transition related to the directional change is about 4800 a. (ⅲ) The virtual geomagnetic pole (VGP) path during the transition is confined over Africa, peaked 90° away from the sampling site, in contrast with the results obtained from the Weinan loess section. The different VGPs are probably attributed to the pedogenesis.     

Subcellular localization of the stripe disease-specific protein encoded by rice stripe virus (RSV) in its vector, the small brown planthopper,Laodelphax striatellus

The stripe disease-specific protein (SP) encoded by the rice stripe virus (RSV) was successfully used as a localization signal of the virus in its vector, the small brown lanthopper,Laodelphax striatellus Fallen. Immunogold particles in large numbers were detected in various parts of the viruliferous females: the ovum, surface of chorion, the midgut lumen, and the columnar cells. Whereas there was none of these particles in the non-viruliferous females and males, and testis of viruliferous males. Endosymbionts (mycetocytes) were abundant, harboring ovaries of both viruliferous and non-viruliferous females, but none in the testis of males. The results provided us with the direct proof that RSV is a ciruculative and propagative plant virus and it was transovarially transmitted alongside with endosymbionts of its vector. Therefore, we deem it a nice lead for future studies on the mechanism of RSV transmission and functioning of its viral proteins.     

Excitation energy distribution between two photosystems inPorphyra yezoensis and its significance in photosynthesis evolution

Comparative investigation on energy distribution between two photosystems were carried out in the sporo- phytes and gametophytes of Porphyra yezoensis. By perfor- ming 77 K fluorescence spectra, we suggested that there probably existed a pathway for energy transfer from PSⅡ to PSⅠ to redistribute the absorbed energy in gametophytes, while no such a way or at minor level in sporophytes. Electron transfer inhibitor DCMU blocked the energy transfer from PSⅡ to PSⅠ in gametophytes, but no obvious effects on sporophytes. These indicated that excitation energy distribution between two photosystems in gametophytes was more cooperative than that in sporophytes. These data in ontogenesis reflected the evolution process of photosynthetic organisms and supported the hypothesis of independent evolution of each photosystem.     

用改进的多区模型计算柴油机中的燃烧和排放

在广安博之直喷式柴油机多区燃烧模型的基础上,改进了燃油雾滴的运动和蒸发模型,以及碳烟的生成与氧化模型,增加了缸内挤流和涡流模型、油滴碰壁和反弹模型,计算结果表明,改进后的油束运动模型比原模型更加合理,较好地解决了空气卷吸问题,在不同转速和负菏工况下均能获得令人满意的精度,能够反映缸内与各区内的燃烧与排放物生成情况,用改进的多区模型可以较好地研究直喷式柴油机的工作过程及其排放。     

渗透胁迫和外源ABA对旱生植物梭梭幼苗某些生理性状的影响

梭梭幼苗在H氏平衡溶液中培养至第4天时,其细胞膜透性、可溶性糖和脯氨酸含量均出现明显的转折变化;甘露醇溶液渗透胁迫引起幼苗的细胞膜电解质渗漏率下降,脯氨酸含量大幅度升高,可溶性糖含量则呈现交替变化;外源ABA则以对上生理指标有不同的影响。因此其作用机制可能与渗透胁迫无直接的相关性。     

二分单纯形算法中子规划的改进

二分单纯形算法中,线性规划问题的最优解是通过求解一系列子问题来实现的,本文针对二分单纯形算法中的子规划问题作进一步研究,提出了一个新的了规划问题来改善问题的不可行性,并确定出了相应的主元旋转规则,给出了相应的子算法,同时进行了数值实验,实验结果表明,调用新子算的二分法与原始二分法相比,迭代次数和计算时间均有所改善,可视为原始二分算法的一种改进算法。     

Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+delta.

Magnetic interactions and magnetic impurities are destructive to superconductivity in conventional superconductors. By contrast, in some unconventional macroscopic quantum systems (such as superfluid 3He and superconducting UGe2), the superconductivity (or superfluidity) is actually mediated by magnetic interactions. A magnetic mechanism has also been proposed for high-temperature superconductivity. Within this context, the fact that magnetic Ni impurity atoms have a weaker effect on superconductivity than non-magnetic Zn atoms in the high-Tc superconductors has been put forward as evidence supporting a magnetic mechanism. Here we use scanning tunnelling microscopy to determine directly the influence of individual Ni atoms on the local electronic structure of Bi2Sr2CaCu2O8+delta. At each Ni site we observe two d-wave impurity states of apparently opposite spin polarization, whose existence indicates that Ni retains a magnetic moment in the superconducting state. However, analysis of the impurity-state energies shows that quasiparticle scattering at Ni is predominantly non-magnetic. Furthermore, we show that the superconducting energy gap and correlations are unimpaired at Ni. This is in strong contrast to the effects of non-magnetic Zn impurities, which locally destroy superconductivity. These results are consistent with predictions for impurity atom phenomena derived from a magnetic mechanism.