WTO Accession and Performance of Chinese Manufacturing Firms

王璐航系厦门大学经济学科2012年新引进的助理教授，博士毕业于加拿大多伦多大学经济系，主要研究兴趣为中国经济、国际贸易与应用微观经济学。其论文曾在比较经济学国际重要期刊Journal of Comparative Economics上发表。本次王璐航发表在《美国经济评论》的论文利用中国加入WTO带来的关税变化研究中国最终产品以及中间投入品的市场开放对于制造业绩效的影响。研究发现最终产品关税的降低一方面压缩了大企业的价格加成，另一方面推动了行业生产效率的提高。与其他国家的经验不同，中国行业效率提升的主要原因是竞争机制的强化进而筛选出了更好的新企业进入。伴随着中间品关税的降低，中国的中间品进口增长有限，但是中间品价格大幅下降。得益于由此带来的成本降低，企业提高了加成率。中间品市场的变化也对新进入企业的生产效率有正的贡献。该文也是厦大经济学科“海归”教师在国际顶级期刊发表研究中国经济问题的众多学术论文的一个典型代表。【Abstract】China’s policy-makers argued that WTO accession and the accompanying trade liberalization would have a beneficial impact on the domestic economy. China’s import tariffs differed tremendously across industry in the earlier years, but converged to an almost uniform low level after WTO entry. We exploit sectoral variation in the extent of tariff reduction to identify the impact of increased import competition on firm performance and its contribution to the significant productivity growth over the 1995–2007 period. We find evidence of strong downward pressure on prices and mark-ups, but limited evidence that imports took away market share from domestic firms. Furthermore, much of the effects on sectoral productivity come from changes at the extensive margin. Sectors that liberalized most tend to attract especially productive entrants, private firms in particular, which can be rationalized by an increase in the minimum productivity threshold needed to survive in these sectors.seminar participants at Columbia University, the Universities of Zurich, Nottingham, and Frankfurt, and several conferences for comments. Funding by SSHRC, ERC and CFI/OIT is gratefully acknowledged

中国入世与出口增长:关于关税不确定性影响的再检验

近期一些文献发现以潜在关税上升空间衡量的关税不确定性的下降对中国加入WTO之后的出口有显著的促进作用。本文利用多重差分的方法在更加宽松的回归模型设定下对这一结论的稳健性进行...中央高校基本科研业务费专项资金资助(ZK1031

激光空泡诱导自由面水花动力学特性研究

空泡与自由面相互作用涉及自由面的强非线性变化和空泡非定常演化,是前沿的基础科学问题。本研究以单空泡与自由面的相互作用为研究对象,以理论分析与实验观测为主要研究手段,建立了自由面约束下空泡溃灭动力学模型,分析了近自由面空泡溃灭和运动规律,发展了空泡运动影响下自由面大变形和飞溅的理论计算方法

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Artificial micro/nanomotors using active particles hold vast potential in applications such as drug delivery and microfabrication. However, upgrading them to micro/nanorobots capable of performing precise tasks with sophisticated functions remains challenging. Bubble microthruster (BMT) is introduced, a variation of the bubble-driven microrobot, which focuses the energy from a collapsing microbubble to create an inertial impact on nearby target microparticles. Utilizing ultra-high-speed imaging, the microparticle mass and density is determined with sub-nanogram resolution based on the relaxation time characterizing the microparticle's transient response. Master curves of the BMT method are shown to be dependent on the viscosity of the solution. The BMT, controlled by a gamepad with magnetic-field guidance, precisely manipulates target microparticles, including bioparticles. Validation involves measuring the polystyrene microparticle mass and hollow glass microsphere density, and assessing the mouse embryo mass densities. The BMT technique presents a promising chip-free, real-time, highly maneuverable strategy that integrates bubble microrobot-based manipulation with precise bioparticle mass and density detection, which can facilitate microscale bioparticle characterizations such as embryo growth monitoring. This work demonstrates a substantial progress of using swimming microrobots to perform precise tasks with sophisticated functions. This magnetic-field-guided bubble microthruster technique presents a promising chip-free, real-time, highly maneuverable strategy that integrates bubble microrobot-based manipulation with precise bioparticle mass and density detection with sub-nanogram resolution. This technique can facilitate microscale bioparticle characterizations such as embryo growth monitoring. imag

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We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies