22 research outputs found

    国外生产者服务贸易自由化与经济增长关系的文献综述

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    生产者服务贸易自由化的发展为研究贸易自由化与经济增长关系提出了新的研究课题。国外学者从理论与实证两方面对生产者服务贸易自由化与一国经济增长的关系进行了大量研究,本文则从生产者服务贸易对经济增长的影响机理方面对这些研究进行梳理和总结,并认为这些理论对中国经济增长具有重要启示

    生产者服务进口对我国制造业全要素生产率的影响分析

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    文章首先分析了生产者服务进口贸易促进工业企业全要素生产率的渠道,并利用理论模型进一步论证了进口的优质生产者服务的种类增加有利于促进工业企业全要素生产率的增长。在理论分析基础上,运用1998—2008年数据进行实证检验,发现我国生产者服务进口贸易对我国大中型工业企业的全要素生产率有显著促进作用,并且发现运输服务进口比新兴的生产者服务进口更能促进工业企业全要素生产率的增长。最后提出若干政策建议

    The Study on the Effect of China’s Development of Producer Service Trade and its Liberalization on Economic Growth

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    随着生产者服务贸易迅速发展,生产者服务贸易自由化趋势不可逆转。面临这种国际形势,我国生产者服务业逐步对外开放。生产者服务业的开放势必对我国经济增长产生重要影响。目前,中国是世界第二大制造国,在相当一段时间内制造业依然是中国经济增长的主要动力。但是中国的制造业一直是以资源能源和廉价劳动力为代价的粗放型发展模式,在全球制造业产业链中处于低附加值产业链下游地位,中国的制造业需要具有知识性与创新性特点的生产者服务业来实现产业升级,而中国的生产者服务业发展又相当滞后,在这种情况下,研究生产者服务贸易自由化对我国经济增长的影响,对于转变我国经济增长方式从而实现经济可持续发展具有重要理论与现实意义。 本文...With the rapid development of trade in producer services, trade liberalization in producer services has become irreversible. Under this circumstance, China’s producer services industry has progressively opened to the outside world. And the opening of the industry will have an important effect on China’s economic growth. China, at present the 2nd top manufacturing country in the world, will have ma...学位:经济学博士院系专业:经济学院_服务贸易学学号:1572007015355

    生产者服务业FDI促进我国资本积累的理论与实证分析

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    文章分析了生产者服务业fdI促进资本积累的机制,并用理论模型加以论证。在理论分析的基础上,利用2005年~2011年间省级面板数据实证检验了我国生产者服务业fdI对我国国内投资的影响,发现前期生产者服务业fdI在全国范围及东部地区对国内投资产生了促进作用,而对中西部地区的投资则产生了挤出效应。因此,我国应进一步加大生产者服务业fdI的引资力度,进一步加强生产者服务业与制造业的产业关联度。福建省社会科学规划项目(项目号:2013B182

    数值优化3~5 μm中红外ZBLAN光纤拉曼激光器的研究

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    3~5μm中红外激光在国防、医疗、自由空间光通信及材料加工等领域具有重要的应用价值。本文提出利用发展较成熟的2.7~2.9μm掺Er激光作为拉曼抽运源,ZBLAN光纤作为拉曼增益介质,为获得激射波长灵活、结构紧凑的3~5μm中红外激光提供一种可行方法。依据光纤拉曼激光器的非线性耦合方程组,数值分析并优化设计了3~5μm中红外ZBLAN光纤一级/二级拉曼激光器。主要研究了ZBLAN光纤长度和输出镜反射率等参数对拉曼激光阈值及输出功率的影响。数值结果表明:1)拉曼阈值随着输出镜反射率的增大而明显下降,且存在最优的ZBLAN光纤长度使一级拉曼阈值最低(4.15 W);2)为获得最高拉曼激光输出功率,最优输出镜反射率分别为84%~98%(一级)和42%~60%(二级),最优ZBLAN光纤长度分别为6.7~8.9 m(一级)和1.5~2.4 m(二级),最优斜率效率分别高达72.36%(一级)和34.06%(二级)。研究工作在一定程度上可为实验研究此类中红外拉曼激光器提供理论指导。国家自然科学基金(61107038);厦门大学大学生创新创业实训项

    Numerical Optimization of 3~5 μm Mid-Infrared ZBLAN Fiber Raman Lasers

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    3~5μM中红外激光在国防、医疗、自由空间光通信及材料加工等领域具有重要的应用价值。本文提出利用发展较成熟的2.7~2.9μM掺Er激光作为拉曼抽运源,zblAn光纤作为拉曼增益介质,为获得激射波长灵活、结构紧凑的3~5μM中红外激光提供一种可行方法。依据光纤拉曼激光器的非线性耦合方程组,数值分析并优化设计了3~5μM中红外zblAn光纤一级/二级拉曼激光器。主要研究了zblAn光纤长度和输出镜反射率等参数对拉曼激光阈值及输出功率的影响。数值结果表明:1)拉曼阈值随着输出镜反射率的增大而明显下降,且存在最优的zblAn光纤长度使一级拉曼阈值最低(4.15 W);2)为获得最高拉曼激光输出功率,最优输出镜反射率分别为84%~98%(一级)和42%~60%(二级),最优zblAn光纤长度分别为6.7~8.9 M(一级)和1.5~2.4 M(二级),最优斜率效率分别高达72.36%(一级)和34.06%(二级)。研究工作在一定程度上可为实验研究此类中红外拉曼激光器提供理论指导。3~5 μm mid- infrared lasers have attracted much attentions due to their wide applications in defences, medicine, free-space optical communication and materials processing.A new scheme for obtaining a3~5 μm flexible-wavelength, compact mid-infrared Raman fiber laser is proposed, using a 2.7~2.9 μm Erdoped fiber laser as Raman pump source and a ZBLAN fluoride fiber as Raman gain medium.Based on the nonlinear coupling equations of Raman fiber lasers, the 3~5 μm mid- infrared ZBLAN fiber 1st/2nd- order Raman lasers are numerically analyzed and optimized.The theoretical optimization is mainly focused on the effects of ZBLAN fiber length and output-mirror reflectivity on the Raman laser threshold and output power.The numerical results show: 1) the Raman laser threshold significantly reduces with the increase of the outputmirror reflectivity, and there always exists the optimized ZBLAN fiber length for the lowest Raman threshold(4.15 W); 2) in order to obtain the high-power Raman laser output, the optimized reflectivities of output mirror are 84~98%(1st-order) and 42~60%(2nd-order), the optimized ZBLAN fiber lengths are 6.7~8.9 m(1st-order)and 1.5~2.4 m(2nd-order), respectively.The optimized slope conversion efficiencies can be as high as 72.36%(1st-order) and 34.06%(2nd-order).These results could provide a theoretical guidance for such mid-infrared fiber Raman lasers.国家自然科学基金(61107038); 厦门大学大学生创新创业实训项

    Research on intermode-beating mode-locked cascaded Raman fiber lasers

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    摘要 光纤激光器因具有易集成化、光束质量好、输出波长可调谐及高转化效率等众多优点,受到广泛研究。与传统稀土掺杂光纤激光器相比,拉曼光纤激光器具有以下特点:1)只要给定恰当的拉曼泵浦源和拉曼增益介质,便能够获得任意波长的激射;2)运用级联拉曼增益,能将激光输出波长扩展到更广泛的新波段。为了获得脉冲激光,常常需要用到调Q或锁模技术。调Q可以获得大的单脉冲能量,而要想获得超短脉冲通常需要用到锁模机制。常用锁模技术需要的外在条件比较多,主动锁模需要在腔内插入调制器或电光晶体等。而被动锁模常常需要借助于可饱和吸收体,且锁模波长主要受限于光纤中的掺杂介质。因此,人们一直在探索自锁模的机制,即无需专门的锁...Abstract Fiber lasers have been widely studied because of its easy integration, good beam quality, tunable output wavelength, high efficiency and so on. Compared with those conventional rare-earth-doped fiber lasers, Raman fiber lasers have the following characteristics: 1) only if the appropriate Raman pump sources and the Raman gain medium are given, it can emit any wavelength lasing, 2) using ...学位:工学硕士院系专业:信息科学与技术学院_光学工程学号:2312012115289

    一种用于原始生殖细胞靶向突变的转基因载体及制备方法和用途

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    本发明公开了一种用于原始生殖细胞靶向突变的转基因载体及制备方法和用途。将本发明提供的载体pTol2(UAS:Cas9)导入单细胞期斑马鱼胚胎,获得的Tg(UAS:Cas9)品系与Tg(kop:KalTA4品系)雌鱼杂交后,获得的杂交胚胎能够在斑马鱼原始生殖细胞中高效、特异、持续表达Cas9基因。在制备突变品系时,以Tg(UAS:Cas9)雄鱼与Tg(kop:KalTA4)雌鱼杂交胚胎作为受体胚胎,直接注射靶向基因的gRNA后,能够有效减少体细胞突变,从而增加注射的P0代胚胎的成活率,同时P0代成鱼能够有效的传递突变,具有广泛应用前景。</p

    First principles study on the structural, electronic, and optical properties of Sc-doped AlN

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    Based on the density functional pseudo-potential method, the structural properties, the band structure, the density of states and the optical properties of the pure and Sc-doped AlN are calculated. The calculation results indicate that the defect of Sc(Al) exists steadily with a certain solubility in the doped system. Sc substitution of the Al site induces effective reduction of the band gap of AlN and the band gap being continuously reduced when increasing Sc concentrations. The existence of the strong hybridization between Sc 3d and N 2p indicates the transport of electrons from Sc atoms to N atoms. Besides, it is shown that the insertion of Sc atom leads to redshift of the optical absorption edge. The intensity of both the imaginary part of the dielectric function and the optical absorption of Al1 - x Sc (x) N are found to decrease with increasing Sc concentrations in the low energy range
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