共查询到19条相似文献,搜索用时 140 毫秒
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对利用乙醛酸、苯酚、邻苯二甲酰亚胺合成DL-对羟基苯甘氨酸的方法进行了研究.最佳工艺条件为:原料摩尔比乙醛酸∶苯酚∶邻苯二甲酰亚胺=1.0∶1.2∶1.2,十八烷基二甲基苄基氯化铵为催化剂,用量为乙醛酸质量的2%,反应时间为8 h,反应温度为60℃,收率达83%以上,产品纯度为99%以上. 相似文献
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乙醛酸的生产及其市场需求 总被引:2,自引:1,他引:2
在文介绍了乙醛酸在精细化学品合成中的典型应用和乙醛酸的基本生产方法,并比较了不同生产方法的各自特点,同时分析了乙醛酸的市场情况,指出了高质量乙醛酸将具有良好的市场前景。 相似文献
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简单介绍乙醛酸的性质和生产方法,重点介绍乙醛酸下游芳香醛及其衍生产品在香料、医药,农用化学品等方面的应用,并分析了这些产品的国内市场现状与趋势。 相似文献
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以—水乙醛酸和尿素为原料,对甲基苯磺酸—磷酸构成的复合酸作为催化剂,利用微波辅助加热技术,经环化缩合反应制备了医药和有机合成中间体及日化助剂尿囊素。研究表明,微波辅助加热可以有效地提高反应效率,反应中的微波辐射功率以500-700W为宜;在微波辐射功率为650W时,微波加热反应15min后尿囊素收率可达60%左右,结果相当于普通加热方式加热反应6h的效果。产品经元素分析、熔点测定、红外光谱表征并用滴定法测定其纯度,尿囊素含量在98%以上。 相似文献
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Philipp Ehrl 《The journal of international trade & economic development》2018,27(3):235-266
The present paper tackles the question whether firms in a middle-wage country offshore production to save labor costs or if they onshore tasks that were offshored from high-wage countries. To distinguish which is the empirically more relevant case, I analyze the effect of importing intermediate inputs on the labor composition using matched employer–employee data and information on trade transactions from the universe of Brazilian firms. Propensity score matching indicates that an intermediate import expansion at the extensive margin leads to employment growth, higher intensities in routine and non-routine manual tasks and an increased share of intermediates exports. These findings thus point out that Brazil's intermediate imports predominantly represent onshored tasks. This result holds regardless of whether intermediate imports from high- or low-wage countries are considered. In line with theoretical considerations, the data show that Brazil's comparative advantage is in medium-complex and routine manual intensive production stages. 相似文献
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文章基于Ngo Van Long等(2005)的分析框架,分析了生产性服务贸易影响中间产品贸易的内在机理。然后,运用中国中间产品贸易1998~2009年的分行业面板数据进行回归,结果显示:生产性服务的进口能促进中间产品的出口,对中间产品进口影响不显著;生产性服务进口对中、低技术密集型中间产品出口的影响较为明显;生产性服务贸易自由化程度的提高使低技术密集型中间产品的出口增加,高技术密集型中间产品的出口减少。 相似文献
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科学刻画逆比较优势进口高技术含量中间品对生产技术革新的影响效应能为制定科学进口国外中间品和提升生产技术革新速度方面的政策提供有益参考,以剖析上述效应为目标的多维细致检验结果表明:首先,制造型和服务型中间品进口技术含量逆比较优势指数对生产技术革新的影响效应呈现倒U型,进口约2.5倍于自身比较优势水平技术含量的中间品能最大化中间品进口的生产技术革新功能,这一结论在多层面检验中均稳健成立。其次,中国中间品进口技术含量逆比较优势指数处于倒U型顶点的左侧正效应区间。对于动态比较优势持续提升的中国而言,在处理好“卡脖子”风险的基础上,可适度提升中间品进口技术含量,以更好地发挥中间品进口的生产技术革新功能。最后,倒U型效应具有非常强的稳定性,多维外部冲击均无法撼动倒U型效应。为此,倒U型效应可谓协调中间品进口和生产技术革新间关系的“铁律”。 相似文献
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我国商业银行中间业务创新研究 总被引:4,自引:0,他引:4
中间业务创新是商业银行自身发展的内在要求 ,也是商业银行应对国内国际激烈竞争的外在要求。本文在对中间业务范围界定的基础上 ,重点分析了我国商业银行中间业务创新发展的主要障碍 ,并提出中间业务创新发展的若干对策。 相似文献
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Denis Stijepic 《The journal of international trade & economic development》2018,27(1):102-122
Structural changes, i.e. long-run changes in the agriculture-manufacturing-services-structure, are a key property of growth and development processes with massive impacts on economy and society and are part of actual debates regarding policy in developing and developed economies. While traditional literature has attempted to explain structural changes by using autarkic models, recent literature has emphasised the importance of deriving theories of structural change using open economy settings. We elaborate on the impacts of intermediate trade on sector structure. In particular, we study how import of intermediate products, which is increasingly feasible due to improvements in transport technology and political integration, affects sector structure in a multi-sector growth model with capital accumulation. This topic has not been studied in the previous literature on structural change in open economies, despite the fact that intermediate imports and capital accumulation are central aspects of modern developing and developed economies. We show that the impacts of intermediate trade on sector structure depend on three factors: productivity gains from trade, specialisation in international trade and development stage. Depending on the constellation of these factors, intermediate trade may accelerate, decelerate or have no effect on structural change. Thus, the effects of intermediate trade may vary strongly across countries. 相似文献
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在产品内国际分工的条件下,中间产品贸易在全部贸易中的比重日益提高,尤其我国工业行业的中间产品贸易更是发展迅速。基于中间产品贸易,国际生产体系的新格局导致了生产向垂直专业化方向发展,依据Hummels等(2001)对垂直专业化比率的计算方法,测算到工业行业出口贸易的垂直专业化程度。本文检验了外国直接投资与垂直专业化生产和中间产品贸易之间的关系,得出外国直接投资分别与垂直专业化生产和中间产品贸易具有单向的因果关系,并且三者之间存在着长期稳定的协整关系。 相似文献
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《Metroeconomica》2018,69(1):195-223
We investigate the impacts on the skill premium and on economic growth in an innovator‐imitator general equilibrium growth model assuming: (a) directed technological change; (b) international trade of intermediate goods; (c) internal costly investment in both physical capital and R&D; and (d) complementarities between intermediate goods in aggregate production. With trade of intermediate goods, the complementarities degree and investment costs influence the economic growth of both countries, but do not affect the countries' skill premia, which are directed by technological knowledge. Additionally, in agreement with related empirical literature, openness to trade of intermediate goods leads to a higher equilibrium skill premium in both countries, whereas its impact on the common growth rate can vary in sign. 相似文献
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我国中间产品贸易探析 总被引:1,自引:0,他引:1
近年来我国中间产品贸易发展迅速,中间产品贸易已成为我国进出口贸易的重要组成部分.文章从比较优势、垂直专业化、价值链及市场内部化等角度阐述了中间产品贸易产生的理论基础,客观地分析了中间产品贸易产生的现实条件和近年来我国中间产品贸易的发展状况,在此基础上提出中间产品贸易的发展将对我国经济及对外贸易发展所产生的具体影响. 相似文献
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“八五”、“九五”期间,我国萘系中间体发展速度强劲。目前我国已成为萘系中间体主要生产、消费和出口国。但是生产能力过剩、产品结构不合理和环保法规的日趋严格对我国萘系有机中间体发展带来巨大的压力,因此加大技术进步、调整产品结构、改变经营观念、严格治理污染和开拓国际市场将是我国萘系有机中间体21世纪的发展主要措施。 相似文献