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991.
“愉快教育”被中外教育家们认为是当今教育应达到的最高境界。本文仅就愉快教育理论的原则在教学实践中的体现略陈管窥之见,以期抛砖引玉。  相似文献   
992.
All organisms with oxygenic photosynthesis contain two photosystems:photosystem Ⅰ(PSⅠ)and photo-systemⅡ(PSⅡ),The minimal photosystem Ⅱ particles which are photochemically active contain three subunits:D1,D2 and cytochrome b559 (Cyt b559),The function of Cyt b559 remains unclear,We have successfully overxpressed the psbF gene,encoding the β subunit of Cyt b559,from a marine cyanobacterium Synechoccous sp.PCC 7002 as a fusion gene and obtained a redox-active from of Cyt b559,When the N-terminal GST protein of the fusion gene product was removed with thrombin ,the PsbF protein was still redox-active,suggesting that the recombinant PsbF can form dimer in Escherichia coli.The absorption spectra of either the oxidized from or the reduced form of both GST fusion protein and the purified PsbF dimer and the difference Spectra between the two forms are the same as that of the Cyt b559 isolated from the higher plants .Redox titration analysis of recombinant PsbF showed that the mid-point redox potential of the recombinant Cyt b559 was approximately 50 mV, which is close to the low potential of Cyt b559 ,The results are helpful to the understanding of locatlization and function of Cyt b559 on thylakoid membranes.Ⅰ  相似文献   
993.
By mixing various concentrations of poly (ethylene glycol), a series of poly(3,4-ethylenedioxythiophene)-poly(styeenesuffonate) composite thin films were prepared.The electrical conductivity of the PEDOT-PSS/PEG thin films was measured by the four-pcobe method. Experimental results showed that the inclusion of poly(ethylene glycol) influenced the electrical conductivity of PEDOT-PSS film significantly. With the increase of PEG concentrations, the electrical conductivity sharply increased to reach a maximum and then slowly decreased down. Furthermore, the PEG molecular weight and environment temperature also played important roles on the electrical conductivity of PEDOT-PSS/PEG thin films. A good linear relationship was found between in σDC and T^-1/2 within the entire temperature range detected.  相似文献   
994.
A Double Haploid (DH) population, 116 plants, derived from the cross between Japonica upland rice IRAT109 and paddy rice Yuefu, planted in PVC pipe under upland ecosystem in 2001 and 2002, was used in this study. Seven root traits, including basal root thickness (BRT), total root number (RN), maximum root length (MRL), root fresh weight (RFW), root dry weight (RDW), ratio of root fresh weight to shoot fresh weight (RFW/SFW) and ratio of root dry weight to shoot dry weight (RDW/SDW), were studied. Using index of drought resistance (IDR), the ratio of yield under upland ecosystem to yield under lowland ecosystem of DH lines, as the criteria of drought resistance, and correla-tion analysis between root traits and IDR, showed that BRT, MRL and RN were significantly correlated with IDR. High IDR lines had thicker BRT, longer MRL and less RN than low IDR lines. A molecular linkage map with 94 RFLP markers and 71 SSR markers covering 1535.1 cM was pro-duced. QTLs and G譋 interactions for BRT, RN, MRL, RFW, RDW, RFW/SFW and RDW/SDW were obtained based on the constructed molecular linkage map and soft-ware QTLmapper version 1.0. A total of 18 additive QTLs and 18 pairs of epistatic QTLs associated with root traits were detected. There were nine additive QTLs and two pairs of epistatic QTLs performed significant interactions with environment. Some QTLs with high general contribution and no G譋 interaction were obtained. Two pairs of epistatic QTLs mrl3 and mrl8, brt3 and brt11a controlling MRL and BRT had high general contributions of 21.51% and 13.03% respectively. An additive QTL and a pair of epistatic QTLs controlling RFW and RDW had high general contributions of 13.50% and 25.64% respectively. Marker assisted selec-tion (MAS) for rice drought resistance based on QTL with high general contribution, low G譋 interaction and tightly linkage with IDR were also discussed.  相似文献   
995.
Tian M  Alt FW 《Nature》2000,407(6800):31, 33
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996.
田鹏 《科学之友》2007,(10):143-144
从线的产生发展谈起,对原始彩陶图案中线条的各类抽象物质进行论述,分析了不同的线性、线质所造成的不同的形式美感.  相似文献   
997.
论述了山西青辣椒的主要病害识别方法,并就其防治方法作了介绍与探讨.  相似文献   
998.
初唐咏物诗不能被简单地视为南朝遗绪,它有力地促成了初唐诗歌声律的成熟,而风骨的产生也是以咏物诗为标志的,从这个意义上来说,咏物诗对盛唐诗歌高潮的到来起到了先导的作用。  相似文献   
999.
分析了Kovar合金与K4玻璃阳极焊的结合机理和主要工艺参数对连接过程的影响,提出了金属与玻璃的连接机理为电场和温度场作用下的离子迁移、复合氧化物过渡层的生成和沉积,电压、温度、压力及试样表面质量是影响离子迁移和结合的主要因素,相匹配的热膨胀系数是防止开裂保证良好连接的必要条件。  相似文献   
1000.
分析软件工程技术的现状,指出其中存在的一些问题,得出应用新技术的必要性.通过研究和实验,提出了在Visual Studio.Net中开发中同步工程的方法,以实现MDA和XP技术的融合,并以一个应用实例验证该方法的有效性.  相似文献   
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