992 resultados para WF 668


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本文试制了铜电极并对碘离子在铜电极上阴极溶出伏安法的各种条件进行了研究。分析了海生物中碘。用三角波循环伏安法观察了电极反应过程。

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比较了用稀土和白川催化体系,制备的70%顺式含量及全反式聚乙炔的拉曼光谱及其随激发光源波长的变化。报道了用稀土催化体系制备的可溶性聚乙炔的拉曼光谱。这些实验结果支持导致反式聚乙炔拉吏异常的主要原因是反式聚乙炔链段共轭长度分散的解释。

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Molecular markers were used to identify and assess cultivars of Laminaria Lamx. and to delineate their phylogenetic relationships. Random amplified polymorphic DNA (RAPD) analysis was used for detection. After screening, 11 primers were selected and they yielded 133 bands in all, of which approximately 99.2% were polymorphic. The genetic distances between gametophytes ranged from 0.412 to 0.956. Two clusters were formed with the unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on the simple matching coefficient. All cultivars of Laminaria japonica Aresch. used for breeding in China fell into one cluster. L. japonica from Japan, L. saccharina (L.) Lam., and L. angustata Kjellm. formed the other cluster and showed higher genetic variation than L. japonica from China. Nuclear ribosomal DNA (rDNA) sequences, including internal transcribed spacers (ITS1 and ITS2) were studied and aligned. The nucleotides of the sequences ranged from 634 to 668, with a total of 692 positions including TTS1, ITS2, and the 5.8S coding region. The phylogenetic tree obtained by the neighbor-joining method favored, to some extent, the results revealed by RAPD analysis. The present study indicates that RAPD and ITS analyses could be used to identify and assess Laminaria germplasm and to distinguish some species and, even intraspecies, in Laminaria.

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本文以鲜活饵料赤子爱胜蚓(Eisenia foetida)为研究对象,从营养学和免疫学的角度研究探讨了蚯蚓对对虾生长和抗病力的影响,为目前虾病问题的解决进行了有益的探索,为蚯蚓在规模化养殖生产中的推广应用提供了参考和依据。主要研究结果如下: 1、以鲜活饵料赤子爱胜蚓为主,双齿围沙蚕(Perinereis aibuhitensis)和人工配合饵料为对照,比较研究了凡纳滨对虾(Litopenaeus vannamei)摄食不同饵料的生长和免疫指标的差异。结果表明:沙蚕和蚯蚓单独投喂或与人工饵料配合投喂都可显著提高凡纳滨对虾的生长速率,提高对虾肌肉蛋白的营养价值,但用沙蚕单独投喂的对虾成活率较低。在增强对虾的免疫功能方面,蚯蚓和沙蚕与人工饵料配合投喂优于蚯蚓和沙蚕单独投喂,同时蚯蚓的饵料效果优于沙蚕。 2、采用鲜活饵料赤子爱胜蚓和人工配合饵料的不同配比投喂处于健康状态下的中国明对虾(Fenneropenaeus chinensis)幼虾,研究了其生长和免疫特征。结果表明:在人工饵料中配合投喂1/4的蚯蚓(干重)可显著加快中国明对虾的生长速率,增加对虾肌肉蛋白质含量,提高对虾肌肉蛋白的营养价值,减少脂肪含量,但对处于健康状态下的中国明对虾幼虾免疫功能的增强无明显效果。 3、考虑到对虾规模化养殖的可行性,采用冰冻蚯蚓赤子爱胜蚓和人工饵料的不同配比投喂处于非健康状态下的凡纳滨对虾,测定分析对虾的生长、营养成分和免疫指标,结果表明:蚯蚓投喂量(干重)占日投喂量的1/4时可以显著提高对虾的生长速率,增加对虾营养,增强对虾免疫功能,提高对虾成活率。 我国蚯蚓资源丰富,来源广泛,研究证实,以蚯蚓作为对虾饵料可增加对虾营养,促进对虾生长,提高机体免疫力,是对虾规模化养殖生产中的优质绿色动物性饵料。

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采用反相高效液相色谱法同时分离和测定了龙胆科獐牙菜属的川西獐牙菜和抱茎獐牙菜中几种酮的含量.色谱柱为Kromasil C_(18)(250 mm * 4.60 mm i.d., 5 μm),流动相为甲醇-0.1%的磷酸水溶液(体积比为73∶27),流速1 mL/min,检测波长260 nm,柱温20 ℃.实验结果表明,该方法具有很好的线性关系与精密度,方法简单、准确、实用性强.

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In the present paper, a 60 h life-time test of a direct ethanol fuel cell (DEFC) at a current density of 20 mA cm(-2) (the beginning 38 h) and 40 mA cm(-2) (the last 22 h) was carried out. After the life-time test, the MEA could not achieve the former performance. X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX) were employed to characterize the anode and cathode catalyst before and after the life-time test. The XRD and TEM results showed that the particle size of the anode catalyst increased from 2.3 to 3.3 nm and the cathode from 3.0 to 4.6 nm. The EDX results of PtSn/C anode catalysts before and after the life-time test indicated that the content of the oxygen and tin, especially the content of the platinum, decreased prominently after the life-time test. The results suggest that the agglomeration of electrocatalysts, the destruction of the anode catalyst together with the fuel/water crossover from anode to cathode concurrently contribute to the performance degradation of the DEFC. (C) 2005 Elsevier B.V. All rights reserved.

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This is an author-created, un-copyedited version of an article accepted for publication in Acta Physica Polonica A. The Version of Record is available online at http://przyrbwn.icm.edu.pl/APP/PDF/118/a118z2p31.pdf

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http://www.archive.org/details/johninnocent00canduoft