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Responses of the Zhe-Min coastal current adjacent to Pingtan Island to the wintertime monsoon relaxation in 2006 and its mechanism

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Science China Earth Sciences 2013年第3期56卷 386-396页

作者： PAN AiJun WAN XiaoFang guo xiaogang JING ChunSheng The Third Institute of Oceanography Ocean Dynamics Laboratory

In conjunction with synchronous remotely sensed winds and sea surface temperature(SST),the spatiotemporal features of the Zhe-Min coastal current(ZMCC),especially responses of the ZMCC adjacent to Pingtan Island(PT) to the wintertime monsoon relaxation in 2006 and corresponding mechanism are investigated based on the field observations.In situ data are acquired from Conductivity-Temperature-Depth(CTD) cruise and Bottom-Mounted Moorings(BMM),which are conducted during a comprehensive survey for the Chinese Offshore Investigation and Assessment Project in winter 2006.It is revealed that the ZMCC is well mixed vertically in winter 2006.The ZMCC(<14°C) recedes during the relaxation of the wintertime monsoon and is accompanied by the enhanced northward shift of the warm,saline Taiwan Strait Mixed Water(TSMW,higher than 14°C and is constituted by the Taiwan Strait Warm Water and the Kuroshio Branch Water).And greatly enhanced southward intrusion of the ZMCC can be detected when the wintertime monsoon restores.Correspondingly,the thermal interface bounded by the ZMCC and the TSMW moves in the northwest/southeast direction,leading to periodic warm/cold reversals of the near-seabed temperature adjacent to the PT.By EOF(Empirical Orthogonal Function) analysis of the large-scale wind fields and wavelet power spectrum analysis of the water level,ocean current and the near-seabed temperature,responses of the ZMCC off the PT to wintertime monsoon relaxation are suggested to be attributed mainly to the southward propagating coastally trapped waves triggered by the impeding atmospheric fronts.As a result,ocean current and near-seabed temperature demonstrate significant quasi-5 d and quasi-10 d subtidal oscillations.By contrast,the onshore/offshore water accumulation resulted from Ekman advection driven by the local winds has minor contributions.

关键词：季风期平潭岛冬季松弛浙闽沿海机制电流海底温度

The spatio-temporal variation of wintertime subtidal currents in the western Taiwan Strait

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Acta Oceanologica Sinica 2017年第11期36卷 4-13页

作者： SHEN Junqiang QIU Yun guo xiaogang PAN Aijun ZHOU Xiwu Third Institute of Oceanography State Oceanic Administration Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology

A new data set of observations by six cruises of ship-mounted acoustic doppler current profiler（SADCP） and three 40 d long bottom-mounted ADCPs（BADCPs） is employed to reveal the spatiotemporal variability of tidal and subtidal currents in the western Taiwan Strait（TWS） during winter season. The results confirm the existence of intense cotidal lines for M2 tidal current, which is located north of 25°N. In this case, no existence of an amphidromic point can be identified. It is also revealed that the counter-wind current（CWC） can extend through the whole western TWS and even occupy the entire water column during winter monsoon relaxation. However,this CWC is observed to be thoroughly overwhelmed by the downwind China coastal current（CCC） during the two big monsoon bloom events in the winter of 2007, and the CCC consequently extends southward throughout the western TWS instead. Most importantly, the variation of the spatial extent for the CWC and the CCC in the western TWS is found to be well explained by the first two modes of the vector empirical orthogonal function（VEOF） analysis, that is, it is mainly controlled by a wind-driven quasi barotropic current as the first mode and slightly modulated by a relatively weak background current with a first-order baroclinic structure as the second mode.

关键词： counter-wind current China coastal current M2 tidal current Taiwan Strait winter season

Seasonal variation of surface currents in the southwestern Taiwan Strait observed with HF radar

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Chinese Science Bulletin 2008年第15期53卷 2385-2391页

作者： ZHU DaYong LI Li LI Yan guo xiaogang Department of Oceanography Xiamen University Xiamen 361005 China The Third Institute of Oceanography State Oceanic Administration Xiamen 361005 China State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China

Long-term measurements from a pair of High-Frequency radar systems deployed near the coast of southern Fujian Province showed that surface currents in the southwestern Taiwan Strait were com-posed mainly of the monsoon-driven, seasonal fluctuation of longshore current and a persistent northeastward background flow with speeds around 10 cm/s. Measurements from bottom-moored ADCPs further indicated that below the surface Ekman layer longshore currents also directed to the north all year round.

关键词：台湾海峡 HF雷达气流季节变化

Responses of Guangdong coastal upwelling to the summertime typhoons of 2006

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Science China Earth Sciences 2012年第3期55卷 495-506页

作者： PAN AiJun guo xiaogang XU JinDian HUANG Jiang WAN XiaoFang Ocean Dynamics Laboratory Third Institute of OceanographyState Oceanic Administration(TIOSOA)Xiamen 361005China

The effects of typhoon intrusion on the Guangdong coastal upwelling system were investigated on the basis of in situ CTD (conductivity-temperature-depth) cruise observations and especially upward-looking ADCP (Acoustic Doppler Current Profil- ers) measurements obtained from a comprehensive survey of the Guangdong coastal region carried out by the Chinese Off-shore Investigation and Assessment Project in the summer of 2006. It was found that northeastward geostrophic advection driven by the summer monsoon has a significant near-seabed onshore component adjacent to Shantou, which in conjunction with upper-level offshore Ekman flow, constitutes the canonical Guangdong coastal upwelling system. Further analyses suggested that the Guangdong coastal upwelling system is sensitive to subtle changes in the typhoon intensity and migration pathway. On one hand, as a typhoon approaches from north of the upwelling system (e.g. Typhoon 0604 (Bilis) and Typhoon 0605 (Kaemi)) in the early phase of intrusion, the enhanced southwesterly leads to exceptional enhancement of the onshore flow; i.e., enhanced upwelling. Afterward, irrespective of the forced ocean responses resulting from the stronger local winds (Typhoon 0604) or the moderate typhoon-induced inertial oscillations (Typhoon 0605), the situation is not conducive to sustaining a stable, persistent upwelling system. On the other hand, when there is typhoon intrusion south of the upwelling system (e.g. Typhoon 0606 (Prapiroon)), the favorable southwesterly tends to be substituted by an anomalous northeasterly, which destroys the traditional coastal upwelling pattern. However, the canonical upwelling system tends to recover within 1-2 days of the typhoon passing.

关键词：台风强度广东沿海夏季季风反应上升流 ADCP 评估项目沿海地区

机器人使用与职业伤害——理论机制与中国证据

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人口与经济 2024年第2期 89-103页

作者：何小钢郭晓斌刘叩明江西财经大学应用经济学院(数字经济学院) 江西南昌330013 暨南大学产业经济研究院广东广州510632

党的二十大报告指出要把保障人民健康放在优先发展的战略位置,与此同时工业机器人的广泛应用对职业伤害的影响日益受到关注。基于全国人口普查数据、国际机器人联合会数据、区域层面工伤数据与中国劳动力动态调查数据,系统地考察了机器... 详细信息

党的二十大报告指出要把保障人民健康放在优先发展的战略位置,与此同时工业机器人的广泛应用对职业伤害的影响日益受到关注。基于全国人口普查数据、国际机器人联合会数据、区域层面工伤数据与中国劳动力动态调查数据,系统地考察了机器人使用对职业伤害的影响效果与作用机制。研究发现,机器人使用显著减少了职业伤害,结论在内生性处理、替换被解释变量、排除国际贸易的影响和排除某些行业趋势的影响等一系列稳健性检验下仍然成立。异质性分析表明,机器人使用能够显著降低工作场所内和机器人使用后期的职业伤害,但对工作场所外和机器人使用前期的影响不显著。相较于在制造业就业比例较低的地区,机器人使用对职业伤害的影响在制造业就业比例较高地区的作用更大。机制分析发现,任务的重新分配和工作条件的改善是机器人使用影响职业伤害的重要渠道。具体而言,机器人使用一方面可以取代高体力、高风险任务,推动这些工人从事体力强度较低、受伤风险较低的任务和职业;另一方面有助于减少工作时长、降低工作强度和优化工作环境,从而改善工作条件。研究为通过智能制造转型提升劳动者职业健康提供了中国的经验证据,为“健康中国”战略目标的实现提供了可行的路径。

关键词：机器人使用任务重配工作条件职业伤害

Inward particle transport driven by biased endplate in a cylindrical magnetized plasma

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Plasma Science and Technology 2024年第3期26卷 126-130页

作者：盖跃徐田超肖池阶郭志彬王晓钢何任川杨肖易张祖煜袁瑞鑫 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China Department of Physics Harbin Institute of TechnologyHarbin 150001People's Republic of China

The inward particle transport is associated with the formation of peaked density profiles,which contributes to improve the fusion rate and the realization of steady-state discharge.The active control of inward particle transport is considered as one of the most critical issues of magnetic confinement fusion.Recently,it is realized preliminarily by adding a biased endplate in the Peking University Plasma Test(PPT)device.The results reveal that the inward particle flux increases with the bias voltage of the endplate.It is also found that the profile of radial electric field(Er)shear is flattened by the increased bias voltage.Radial velocity fluctuations affect the inward particle more than density fluctuations,and the frequency of the dominant mode driving inward particle flux increases with the biased voltage applied to the endplate.The experimental results in the PPT device provide a method to actively control the inward particle flux using a biased endplate and enrich the understanding of the relationship between E_(r)×B shear and turbulence transport.

关键词： inward particle transport biased endplate turbulent transport

Numerical study on the restriction speed of train passing curved rail in cross wind

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Science China(Technological Sciences) 2009年第7期52卷 2037-2047页

作者： CHEN RuiLin ZENG QingYuan ZHONG XinGu XIANG Jun guo xiaogang ZHAO Gang School of Civil Engineering&Mechanics Xiangtan UniversityXiangtan 411105China School of Civil Architecture Central South UniversityChangsha 410075China School of Civil Engineering Hunan University of TechnologyXiangtan 411201China AMEC Toronto M5A5G7Canada

The results of numerical investigations of aerodynamic forces and moment coefficients of flow passing a simplified train geometry under different wind speeds are summarized. To compute numerically the different coefficients, the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations, combined with the k-ε turbulence model, were solved using finite volume technique. The pres-sure-velocity fields were coupled using the SIMPLE algorithm. At each iteration the pressure correction was obtained by solving a velocity divergence-derived Poisson-like equation. With the computed aerodynamic forces, the formula of the restriction speed at which the train passed curved rail in cross wind was deduced to analyse the influences of aerodynamic forces on the restriction speed. Results of numerical investigations showed that aerodynamic lift and overturn moment increased more and more rapidly with train speed and wind speed. The enhancement trends showed nonlinear phenomena and enhanced risk in the course of train movement. When the train travels at a high speed and encounters a huge cross wind, the influence involved by nonlinear risk increment will extremely impair safety of train. The following conclusion can also be drawn: The effect of aerodynamic lift makes restriction speed reduce, however, the influences of aerodynamic drag to the limit train speed rest on the direction of wind flow. When the wind blows from inner rail to outer rail, aerodynamic forces shall reduce the restriction speed, by contraries, when the wind blows from outer rail to inner rail, aerodynamic forces shall increase the restriction speed.

关键词： cross wind aerodynamic performance finite volume method turbulence model restriction speed curved rail

Laboratory observation of electron energy distribution near three-dimensional magnetic nulls

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Plasma Science and Technology 2024年第3期26卷 46-52页

作者：何任川徐田超杨肖易肖池阶张祖煜袁瑞鑫王晓钢郭志彬余修铭盖跃 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China Department of Physics Harbin Institute of TechnologyHarbin 150001People's Republic of China

The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection process.To explore electron acceleration in a 3D magnetic null topology,we constructed a pair of 3D magnetic nulls in the PKU Plasma Test(PPT)device and observed acceleration of electrons near magnetic nulls.This study measured the plasma floating potential and ion density profiles around the 3D magnetic null.The potential wells near nulls may be related to the energy variations of electrons,so we measured the electron distribution functions(EDFs)at different spatial positions.The axial variation of EDF shows that the electrons deviate from the Maxwell distribution near magnetic nulls.With scanning probes that can directionally measure and theoretically analyze based on curve fitting,the variations of EDFs are linked to the changes of plasma potential under 3D magnetic null topology.The kinetic energy of electrons accelerated by the electric field is 6 eV(v_(e)~7v_(Alfvén-e))and the scale of the region where accelerating electrons exist is in the order of serval electron skin depths.

关键词： electron acceleration EEDF 3D magnetic null magnetic reconnection

国际大宗商品价格波动对中国金融市场的风险溢出效应

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中国西部 2024年第1期 85-95页

作者：郭娜石艳菲郭小刚天津财经大学金融学院天津300222 中电建(北京)基金管理有限公司北京100048

文章采用TVP-VAR-DY模型考察了国际大宗商品与我国金融市场间的时变波动溢出效应。研究发现:(1)静态溢出效应分析表明,国际大宗商品市场与我国商品市场间的双向波动溢出效应最大,其次为股票市场。(2)方向性溢出效应分析表明,与极端风险... 详细信息

文章采用TVP-VAR-DY模型考察了国际大宗商品与我国金融市场间的时变波动溢出效应。研究发现:(1)静态溢出效应分析表明,国际大宗商品市场与我国商品市场间的双向波动溢出效应最大,其次为股票市场。(2)方向性溢出效应分析表明,与极端风险事件关联性更高的国际大宗商品市场以及我国商品和股票市场呈现更加显著的时变特征。(3)净溢出和净配对溢出效应表明,国际大宗商品市场、我国商品和股票市场属于风险的净传递者,且国际大宗商品市场与我国商品、外汇、股票市场的净配对溢出指数更高。

关键词：国际大宗商品中国金融市场风险溢出 TVP-VAR-DY模型