980 resultados para 1905


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The triblock copolymers, poly(styrene-b-isoprene-b-epsilon-caprolactone)s (PS-b-PI-b-PCL) have been synthesized successfully by combination of anionic polymerization and ring-opening polymerization. Diblock copolymer capped with hydroxyl group, PS-b-PI-OH was synthesized by sequential- anionic polymerization of styrene and isoprene and following end-capping reaction of EO, and then it was used as macro initiator in the ring-opening polymerization of CL. The results of DSC and WAXD show big effect of amorphous PS-b-PI on the thermal behaviors of PCL block in the triblock copolymers and the lower degree of crystalline in the triblock copolymer with higher molecular weight of PS-b-PI was observed. The real-time observation on the polarized optical microscopy shows the spherulite growth rates of PCL27, PCL328 and PS-b-PI-b-PCL344 are 0.71, 0.46 and 0.07 mu m s(-1), respectively. The atomic force microscopy (AFM) images of the PS90-b-PI66-b-PCL-(28) show the columns morphology formed by it's self-assembling.

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用真空电弧熔炼合成了稀土基AB2 型合金.真空电弧合成的稀土基AB2 型合金不具有Laves Phase 的单相结构,而是由多相组成.用XRD、SEM和XPS 对多次充/放电循环后电极合金结构、形貌进行了分析,用ICP-AES 分析电介质溶液中电极合金组成元素的含量,探索了稀土基AB2 型合金作为金属氢化物电极的衰变机理.实验结果表明:腐蚀是稀土基AB2 型合金氢化物电极合金结构变化和电化学性能衰变的主要原因.

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In addition to 10 known compounds (7-16), one new brominated diterpene, 10-hydroxykahukuene B (1), two new sesquiterpenes, 9-deoxyelatol (2) and isodactyloxene A (3), one new brominated C-15-acetogenin, laurenmariallene (4), and two new naturally occurring halogenated sesquiterpenes (5 and 6) that were previously obtained as intemediates in a biomimetic synthetic study of rhodolaureol and rhodolauradiol have been isolated and identified from the organic extract of the marine red alga Laurencia mariannensis. The structures of these compounds were established by spectroscopic methods. The antibacterial and antifungal activities of new compounds 1-4 were evaluated.

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本文根据中国科学院海洋研究所收藏的豆蟹科标本和国内外相关文献,进行了中国海域豆蟹科的分类学研究。作者克服了豆蟹科分类难度大,研究积累较少,种的界限不清等困难,在短期内初步查清了中国海域豆蟹科种类及分布情况,共记述5亚科12属 40种。发现4新记录属,9新记录种,和豆蟹属1未定种Pinnotheres sp.,丰富了中国海豆蟹科区系内容,列出了共栖种中国海域全部记录过的宿主。 作者对鉴定过程中出现的疑难问题:“中型三强蟹Tritodynamia intermedia Shen, 1935是否为霍氏三强蟹 Tritodynamia horvathi Nobili, 1905的同物异名” 进行了细致比较、研究,否定了通行多年的Sakai(1976)的“T. intermedia Shen为T. horvathi Nobili的次异名”的结论,肯定了二者均为有效种。 对中国海域豆蟹科种类地理分布初步研究表明其分布与日本海域和东南亚海域都有相似之处,但有显著不同:仅发现于中国海域而未见于日本海域的豆蟹属Pinnotheres多达8种:涨腹豆蟹Pinnotheres excussus Dai et al., 1980,球豆蟹Pinnotheres pilulus Dai et al., 1980,锯颚豆蟹Pinnotheres serrignathus Shen, 1932,宽豆蟹Pinnotheres dilatatus Shen, 1932,青岛豆蟹Pinnotheres tsingtaoensis Shen, 1932,海阳豆蟹Pinnotheres haiyangensis Shen, 1932,钝颚豆蟹Pinnotheres obtusidentata(Dai et al., 1980),光豆蟹Pinnotheres luminatus Dai et al., 1980);仅发现于中国海域的三强蟹属Tritodynamia有4种:福建三强蟹Tritodynamia fujianensis Chen, 1979,长腿三强蟹Tritodynamia longipropodum Dai et al., 1980,宽身三强蟹 Tritodynamia dilatatum Yang et Sun,1996和海南三强蟹 Tritodynamia hainanensis Dai et al.g, 1980;而未发现于中国海域的日本特有种多达13种。结果表明这一类群由于共栖和地域分化程度较高乃至地区性特有种数显著较多。 论文通过对豆蟹科系统分类和初步的动物地理学研究,搞清了中国海豆蟹科的种和分布、多样性及其宿主等基本情况。为今后研究豆蟹科种类生物学、生态学特性提供了基础资料。

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A new species of Spionidae, Scolelepis (Scolelepis) daphoinos sp. nov., is described and illustrated from northern China seas. The species was frequently encountered and highly abundant on sand beaches, but rarely found in subtidal areas. It was formerly misidentified as S. (S.) squamata (Muller, 1806) in China but differed from the latter species in several details in morphology, including the presence of obvious reddish pigmentation patches and the absence of unidentate hooded hooks. Another two Scolelepis species, S. (S.) lingulata Imajima, 1992 and S. (S.) variegata Imajima, 1992, are reported for the first time from Chinese waters. Two species of Scolelepis, S. (S.) globosa Wu & Chen, 1964 and S. (S.) lefebvrei (Gravier, 1905), were reported previously; therefore, five species in this genus are known from China in total. A key to all Scolelepis species from Chinese waters is provided.

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A newly synthesized benzoic-triazole derivative 3,5-dimethylbenzoic acid [1,2,4]triazol-l-ylmethyl ester (DBT) was investigated as a corrosion inhibitor of mild steel in 1 M HCl solution using weight loss measurements, potentiodynamic polarization, SEM, and EIS methods. The results revealed that DBT was an excellent inhibitor, and the inhibition efficiencies obtained from weight loss and electrochemical experiments were in good agreement. Using the potentiodynamic polarization technique, the inhibitor was proved to have a mixed-type character for mild steel by suppressing both anodic and cathodic reactions on the metal surface. The number of water molecules (X) replaced by a molecule of organic adsorbate was determined from the Flory-Huggins, Dhar-Flory-Huggins, and Bockris-Swinkels substitutional adsorption isotherms applied to the data obtained from the gravimetric experiments performed on a mild steel specimen in 1 M HCl solution at 298 K.

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本文的目的在于讨论柔性制造系统(FMS)的长期计划中的任务混合比的问题,并提出了一个两级的递阶结构.下级用 Gcrshwin 提出的方法以确定任务转换频率,上一级则确定整个系统的任务混合比,从而提高整个系统的生产率.

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对贵阳地区一生境内不同生长条件(石生苔藓、无树冠、不同树冠类型以及同种树冠不同树冠厚度)下的细叶小羽藓(Haplocladium microphyllum(Hedw.)Broth)碳氮同位素进行了研究。不同生境的苔藓铲δ^13C和δ^15N值具有相似的变化趋势和明显的相关关系。石生苔藓δ^13C和δ^15N值比土生苔藓偏高指示了其相对干燥和受到干沉降控制的生境;树冠下方光照条件差、湿度高、缺少干沉降氮的输入是苔藓δ^13C和δ^15N值偏低的主要原因;而树冠类型、叶片形态、叶面性质造成树冠对大气沉降氮吸收能力的不同是三种树冠下方苔藓氮同位素组成差异的潜在因素。此外,同一树冠(桂花树Osmanthus fiagrans Lour.)下方苔藓的氮含量和碳氮同位素平均组成与树冠厚度呈线性关系。尤其是δ^15N的响应很好地反映了吸收过程中树冠厚度对大气沉降氮源同位素组成的控制作用。结果表明。苔藓δ^13C值能很好地指示苔藓的生境差异和生理响应(如光合作用能力和氮需求等);而δ^15N值在示踪氮源和反映不同树冠吸收过程的同位素分馏效应方面更具有优势,二者的相关关系是环境因素相互作用的重要线索。此外,细叶小羽藓Haplocladium microphyllum(Hedw.)Broth具有高效利用大气沉降氮和分布广泛等特点,可进一步应用于该地区大气氮沉降的指示或监测研究.

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http://www.archive.org/details/missionaryheroes00unknuoft

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http://www.archive.org/details/aretrospect00tayluoft

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Boston University Theological Library

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http://www.archive.org/details/thingsastheyarem00wilsuoft

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Boston University Theology Library

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This file contains a finding aid for the American Palestine Exploration Society Photograph Collection. To access the collection, please contact the archivist (asorarch@bu.edu) at the American Schools of Oriental Research, located at Boston University.