53 research outputs found

    Contract Enforcement Efficiency and Production Organization Mode: Theoretical and Empirical Analysis of China’s Manufacturing Industry

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    当一家企业作为最终产品生产商获取中间投入品时,需要在不同的组织形式中做出选择。首先,企业可以并购中间投入品供应商,以垂直一体化的形式获得中间投入品,此时的投入品交易是在企业边界内进行的;其次,该企业还可以通过对等贸易的形式向独立的供应商购买中间投入品,即在企业的边界外进行交易。企业采取垂直一体化或外包形式是受到外部因素的影响,还是出于企业自身特征的考虑?近年来,越来越多的经济学家将国际贸易理论的主体缩小至产业乃至企业内贸易中,尝试回答企业生产组织决定方面的问题。Antràs(2003)首次构造了封闭经济的产权模型,说明当中间投入品供应商的投资不可签约时,通过垂直一体化能够更有效地控制中间投入品...The final product manufacturers need to make a choice from different organization forms when they want to obtain intermediate inputs. Companies can make acquisition of intermediate inputs suppliers to obtain the inputs by vertical integration, when the inputs transaction is carried out within the boundaries of the enterprise. Otherwise, the company could also trade with suppliers to purchase the i...学位:经济学硕士院系专业:经济学院_国际贸易学学号:1572011115185

    我国科技期刊媒体融合现状与发展方向

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    摘要【目的】调研国际科技期刊媒体融合发展现状,探寻我国科技期刊媒体深度融合发展方向。【方法】基于我国科技期刊实际、政策导向与专家意见,对我国科技期刊的媒体融合现状进行相关文献调研、案例分析对比。【结果】明确媒体融合概念、特点、发展历程及国内外发展状况,分析现阶段我国科技期刊融合进程中的不足,提出我国科技期刊媒体融合发展方向与着眼点。【结论】媒体融合具有帕累托效应,需尽早建立科技期刊融合效果评价体系; 相较于国外科技期刊集团化运作、立体化网络运营与矩阵化传播模式,我国科技期刊媒体融合具有自身特色,但融合质量参差不齐、运营管理薄弱; 可依据&ldquo;1 个总趋势、5 个特质、N 个创新点&rdquo;的思路促进我国科技期刊媒体融合的转型升级。</p

    双蒲散对慢性萎缩性胃炎大鼠胃黏膜细胞TGF-β1/Smad3信号通路的影响

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    目的 :观察双蒲散对慢性萎缩性胃炎的治疗作用以及胃黏膜细胞TGF/Smad信号通路的影响。方法 :40只SD大鼠随机分为正常组、模型组、双蒲散组和维酶素组,每组10只。采用N-甲基-N`-硝基-N-亚硝基胍(MNNG)方法复制慢性萎缩性胃炎大鼠模型,正常组不处理,模型组只造模不干预,其余两组造模16周后分别灌胃双蒲散和维酶素4周。光镜观察胃黏膜组织病理学,酶联免疫吸附法测定胃黏膜组织Bcl-2、P53、PCNA、Ag-NORs、EGF、TGF-β1与Smad3蛋白的表达。结果 :与正常组比较,模型组大鼠胃黏膜组织Bcl-2、P53、PCNA、Ag-NORs、EGF、TGF-β1的表达皆明显升高,Smad3皆显著下降(P<0.05);与模型组比较,双蒲散组大鼠胃黏膜组织Bcl-2、P53、PCNA、Ag-NORs、EGF、TGF-β1的表达皆明显下降,Smad3皆显著升高(P<0.05),其效应显著高于维酶素组。结论 :双蒲散可通过调节TGF-β1/Smad3信号通路调节慢性萎缩性胃炎大鼠胃黏膜细胞的增殖和凋亡,抑制胃黏膜细胞的异型增生,阻断慢性萎缩性胃炎向胃癌前病变发展。国家自然科学基金项目(81260556);; 江西省自然科学基金项目(20131512040019

    Separation and purification of catalpol from Radix Rehmanniae

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    An ultrasonic extraction technology of preparing catalpol from Radix Rehmanniae was optimized by a uniform experimental design.The optimum conditions for ultrasonic extraction were thus established: 68% (vol) ethanol aqueous solution as extraction solvent,the volume(ml) to mass(g) ratio of extraction solvent to feed of 5∶1,the ultrasonic treatment time of 36 min.The crude catalpol obtained from the optimized ultrasonic extraction technology was further purified by selective adsorption with macroporous resin.The adsorption capacities and desorption yields of ten kinds of macroporous resins for catalpol were investigated.The results showed that H103 resin possessed the best performance.The properties of dynamic adsorption and desorption of H103 resin for catalpol were subsequently investigated on adsorption column.The optimum conditions for adsorption and desorption were determined.The concentration of catalpol in the loaded sample solution was 6.15 mg·ml-1,the flow rate was 1.0 ml·min-1,the volumetric percentage of ethanol in the eluting solvent was 75%,the elution flow rate was 0.5 ml·min-1 and the elution volume was 3.33 BV(bed volume).Under the above conditions,the purity of catalpol product eluted from the column packed with H103 resin reached 62.39% while that of the crude catalpol was only 10.01%

    我国科技期刊媒体融合制约因素及突破路径探析

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    目的 分析并探讨我国科技期刊媒体深度融合的制约因素及突破路径。方法 通过文献调研、案例分析与对比,基于政策导向、专家意见及期刊现实情况,对期刊的发展现状进行归纳与分析。结果 系统梳理了制约我国科技期刊媒体融合的4个主要因素,提出可从5个方面进行融合转型升级路径探索。 结论 制约我国科技期刊媒体融合的因素主要包括管理机制与相关政策、人才与团队构建、先进技术与内容产品、发展资金等。要实现科技期刊与新媒体的深度融合,应坚持&ldquo;五位一体&rdquo;的融合路径:坚持正确的理念、思维及意识;组建&ldquo;领军人才+专才&rdquo;的团队或联盟;构建立体化网络平台与全媒体产业链,形成传播媒体矩阵;用技术外包实现近期内容创新,同时加大技术自主研发力度,以掌握深度融合的主动权;管理运营要注重顶层设计、资源有效配置、利用最大化,促进科技期刊事业的可持续发展。</p

    CdS量子点表面巯基酸分子排列方式的宽带和频光谱研究

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    巯基酸是一种常用的量子点表面配体,对量子点的光电属性和催化活性具有重要影响。用宽带和频光谱(BB-SFG)研究巯基酸分子(HS-(CH2)n-COOH,n = 2,5,10)在金膜和硫化镉(CdS)量子点表面的排列方式。结果表明:在金表面上3种自组装巯基酸单分子膜,都可以检测到与巯基和羧基相连的两个亚甲基的C-H振动和频谱峰。而在CdS量子点表面,短链的HS-(CH2)2-COOH和HS-(CH2)5-COOH处于较无序的混乱包覆状态,检测不到C-H振动和频谱峰;但长链的HS-(CH2)10-COOH在CdS量子点表面是较有序的类似反胶束状的排列,可以检测到与羧基相连的亚甲基的C-H振动谱峰。国家重点研发计划项目(2017YFA0206500,2016YFA0200702)国家自然科学基金(21327901)

    The Long March Spirit of Youth's Development

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    长征是中国共产党领导人民和军队进行英勇斗争的伟大史诗,在这一过程中形成的长征精神,是中国共产党在革命实践中历练出的一笔宝贵的精神财富。青年是国家的未来,民族的希望,在新时期弘扬长征精神,应该赋予它以新的时代内涵,要以其独特的魅力和德育价值,教育和引导当代青年,树立正确的价值观、人生观、世界观,做一个合格的社会主接班人。The Long March is a great epic that the Communist Party of China led his people and army made a heroic fight with the enemy,and the Long March spirit which formed in this process,is a precious wealth of the Chinese Communist Party in the long revolutionary practice.Youth are not only the future of our country,but also the hope of our nations,so in the new era,the Long March spirit should be given a new meaning when we promote it,it should be used to educate and guide the contemporary youth with its unique charm and moral value,and to build a correct values,outlook on life,world outlook,and finally to be a qualified socialist successors

    共聚物Pluronic P103对牛血清白蛋白荧光光谱的猝灭

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    应用静态荧光光谱研究了嵌段共聚物PluronicP103对牛血清白蛋白(BSA)荧光光谱的猝灭。研究表明,PluronicP103对BSA的荧光有猝灭作用,动态猝灭是引起BSA荧光猝灭的主要原因。发现嵌段共聚物PluronicP103在水溶液中的蔟集状态影响其与BSA的相互作用,以胶团形式存在的PluronicP103对BSA的猝灭作用更强

    共聚物Pluronic P103对牛血清白蛋白荧光光谱的猝灭

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    应用静态荧光光谱研究了嵌段共聚物Pluronic P103对牛血清白蛋白(BSA)荧光光谱的猝灭。研究表明,Pluronic P103对BSA的荧光有猝灭作用,动态猝灭是引起BSA荧光猝灭的主要原因。发现嵌段共聚物Pluronic P103在水溶液中的蔟集状态影响其与BSA的相互作用,以胶团形式存在的Pluronic P103对BSA的猝灭作用更强

    共聚物Pluronic P103对牛血清白蛋白荧光光谱的猝灭

    No full text
    应用静态荧光光谱研究了嵌段共聚物Pluronic P103对牛血清白蛋白(BSA)荧光光谱的猝灭。研究表明,Pluronic P103对BSA的荧光有猝灭作用,动态猝灭是引起BSA荧光猝灭的主要原因。发现嵌段共聚物Pluronic P103在水溶液中的蔟集状态影响其与BSA的相互作用,以胶团形式存在的Pluronic P103对BSA的猝灭作用更强
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