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Formation of Well-Mixed Warm Water Column in Central Bohai Sea During Summer: Role of High-Frequency Atmospheric Forcing

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Journal of Ocean University of China 2017年第6期16卷 945-952页

作者： MA Weiwei wan Xiuquan wanG Zhankun LIU Yulong wan kai College of Oceanic and Atmospheric Sciences Ocean University of China Qingdao 266100 P. R. China Physical Oceanography Laboratory/CIMST Ocean University of China and Qingdao National Laboratory for Marine Science and Technology Qingdao 266100 P. R. China National Centers for Environmental Information NOAA Silver Spring MD 20910 USA Earth System Science Interdisciplinary Center University of Maryland College Park MD 20740 USA National Marine Data and Information Service Tianjin 300171 P. R. China Beihai Offshore Engineering Survey Institute SOA Qingdao 266061 P. R. China

The influence of high-frequency atmospheric forcing on the formation of a well-mixed summer warm water column in the central Bohai Sea is investigated comparing model simulations driven by daily surface forcing and those using monthly forcing data. In the absence of high-frequency atmospheric forcing, numerical simulations have repeatedly failed to reproduce this vertically uniform column of warm water measured over the past 35 years. However, high-frequency surface forcing is found to strongly influence the structure and distribution of the well-mixed warm water column, and simulations are in good agreement with observations. Results show that high frequency forcing enhances vertical mixing over the central bank, intensifies downward heat transport, and homogenizes the water column to form the Bohai central warm column. Evidence presented shows that high frequency forcing plays a dominant role in the formation of the well-mixed warm water column in summer, even without the effects of tidal and surface wave mixing. The present study thus provides a practical and rational way of further improving the performance of oceanic simulations in the Bohai Sea and can be used to adjust parameterization schemes of ocean models.

关键词： Bohai Sea warm water column numerical simulation, high frequency forcing

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Sulfur-modified nickel selenide as an efficient electrocatalyst for the oxygen evolution reaction

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Journal of Energy Chemistry 2021年第11期30卷 198-203,I0005页

作者： kai wan Jiangshui Luo Xuan Zhang Palaniappan Subramanian Jan Fransaer Department of Materials Engineering KU LeuvenLeuven 3001Belgium College of Materials Science and Engineering Sichuan UniversityChengdu 610065SichuanChina

The sluggish four-electron transfer of the oxygen evolution reaction(OER)limits the performance of water ***,OER electrocatalysts based on earth-abundant elements are urgently *** doping has been an efficient approach to boost the intrinsic OER activity of the active sites by modifying the electronic ***,a simple anion substitution strategy is reported that increases the OER activity of nickel selenides via a one-step hydrothermal treatment of a metal–organic framework *** resulting S-substituted Ni_(3)Se_(4) nanoparticles display distortion of their crystal *** expected,the sulfur substitution modifies the electronic structure of Ni_(3)Se_(4) and leads to outstanding electrocatalytic *** the S-substituted Ni_(3)Se_(4) catalysts exhibit higher OER activities than the original Ni_(3)Se_(4).The optimized catalyst achieves a current density of 10 mA cm^(−2) at an overpotential of 275 mV with a Tafel slope of 64 mV dec^(−1) in 1.0 M *** addition to its electrochemical activity,the S-Ni_(3)Se_(4)-2 catalyst also exhibits good stability with only a 7.5%increase in overpotential at 50 mA cm^(−2) after 100 *** work demonstrates one strategy to modify the electronic structure of transition metal compounds by anion regulation.

关键词： Anion substitution Nickel selenide Electronic structure Oxygen evolution reaction

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Role of Stokes Drift in Ocean Dynamics Under Typhoon Conditions in the Bohai Sea

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Journal of Ocean University of China 2024年第1期23卷 33-45页

作者： LI Haoqian wan kai wanG Menghan DENG Zeng’an CAO Yu North China Sea Marine Forecasting Center Qingdao 266061China Shandong Provincial Key Laboratory of Marine Ecology and Environment&Disaster Prevention and Mitigation Qingdao 266061China North China Sea Offshore Engineering Survey Institute Qingdao 266061China School of Marine Science and Technology Tianjin UniversityTianjin 300072China South China Sea Marine Forecasting Center Guangzhou 510006China

The effect of Stokes drift production(SDP),which includes Coriolis-Stokes forcing,Langmuir circulation,and Craik-Lei-bovich vortexes,on the upper ocean during typhoon passage in the Bohai Sea(BS),China,is investigated by using a coupled wave-current *** role of SDP in turbulent mixing and the further dynamics during the entire typhoon period are comprehensively *** results show that SDP greatly increases turbulent mixing at all depths under typhoon conditions by up to seven times that under normal weather *** generally strengthens sea surface cooling by more than 0.4℃,with the maximum reduction in sea surface temperature(SST)at the during-typhoon stage exceeding 2℃,which is approximately seven times larger than that under normal weather *** SDP-induced decrease in current speed can exceed 0.2ms^(-1),and the change in current direction is generally opposite the wind *** results suggest that Stokes drift depresses the effect of strong winds on currents by intensifying turbulent *** layer depth(MLD)is distinctly increased by O(1)during typhoons due to SDP and can deepen by more than *** addition,the continuous effects of SDP on SST,current,and MLD at the after-typhoon stage indi-cate a hysteretic response between SDP and typhoon actions.

关键词： Stokes drift production Langmuir turbulence rurbulent mixing typhoon coupled model

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Steric hindrance shielding viologen against alkali attack in realizing ultrastable aqueous flow batteries

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Journal of Energy Chemistry 2024年第10期97卷 529-534,I0011页

作者： Liwen wang kai wan Xianzhi Yuan Zhipeng Xiang Zhiyong Fu Zhenxing Liang Guangdong Provincial Key Laboratory of Fuel Cell Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510641GuangdongChina State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510641GuangdongChina Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center Jieyang 522000GuangdongChina

Viologens known as a kind of promising negolyte materials for aqueous organic redox flow batteries,face a critical stability challenge due to the S_N2 nucleophilic attack by hydroxide ions(OH-)during the battery *** this work,a N-cyclic quaternary ammonium-grafted viologen molecule,viz.1,1'-bis(4,4'-dime thylpiperidiniumyl)-4,4'-bipyridinium tetrachloride((DBPPy)Cl_(4)),is developed by the molecular engineering *** obtained(DBPPy)Cl_(4) molecule shows a decent solubility of 1.84 M and a redox potential of-0.52 V ***/AgCl,Experimental and theoretical results reveal that the grafted N-cyclic quaternary ammonium groups act as the steric hindrance to prevent nucleophilic attack by OH~-,increasing the alkali resistance of the electroactive *** symmetrical battery with 0.50 M(DBPPy)Cl4shows negligible decay during the 13-day cycling *** demonstration,the flow battery utilizing 1.0 M(DBPPy)Cl_(4) as the negolyte and 1-(1-oxyl-2,2',6,6'-tetramethylpiperidin-4-yl)-1'-(3-(trimethylammonio)propyl)-4,4'-bipyridinium trichloride as the posolyte exhibits a high capacity retention rate of 99.99%per cycle at 60 mA cm^(-2).

关键词： Aqueous organic flow batteries Viologen Stability Steric hindrance Alkali resistance

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Science Letters:Nitrogen doping of activated carbon loading Fe_2O_3 and activity in carbon-nitric oxide reaction

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 707-711页

作者： wan Xian-kai ZOU Xue-quan SHI Hui-xiang wanG Da-hui Institute of Environmental Engineering Zhejiang University Hangzhou 310027 China

Nitrogen doping of activated carbon loading Fe2O3 was performed by annealing in ammonia, and the activity of the modified carbon for NO reduction was studied in the presence of oxygen. Results show that Fe2O3 enhances the amount of surface oxygen complexes and facilitates nitrogen incorporation in the carbon, especially in the form of pyridinic nitrogen. The modified carbon shows excellent activity for NO reduction in the low temperature regime （〈500℃） because of the cooperative effect of Fe2O3 and the surface nitrogen species.

关键词： Activated carbon Nitric oxide Doping Iron oxides Catalytic reduction

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Tidal Effects on the Bottom Thermal Front of North Yellow Sea Cold Water Mass near Zhangzi Island in Summer 2009

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Journal of Ocean University of China 2019年第4期18卷 751-760页

作者： XIA Yingying BAO Xianwen SONG Dehai DING Yang wan kai YAN Yuhan Key Laboratory of Physical Oceanography Ministry of Education Ocean University of China and Qingdao National Laboratory for Marine Science and Technology Qingdao 266100 China College of Oceanic and Atmospheric Sciences Ocean University of China Qingdao 266100 China Beihai Offshore Engineering Survey Institute State Oceanic Administration Qingdao 266061 China

Three seabed-mounted TD/CTD chains and two upward-looking acoustic Doppler current profilers (ADCPs) in the southwest of Zhangzi Island are used and a simultaneous cruise observation in the northern North Yellow Sea (NYS) is conducted to study temperature variation in the bottom thermal front zone of the NYS Cold Water Mass (NYSCWM) during the summer of 2009. In the flood-ebb tidal cycles, the bottom temperature decreases (increases) during flood (ebb) tides, which are dominated by the tidal-current induced horizontal advection. The ebb tide-induced temperature increase is larger than the flood tide-induced tempera- ture decrease due to seasonal warming. In the spring-neap tidal cycles, the temperature and the vertical temperature structure show notable fortnightly variation from 16 July to 25 August. The bottom temperature increases from neap to spring tides and decreases from spring to neap. The Richardson number demonstrates strengthened vertical mixing during spring tides but enhanced stratifica- tion during neap tides. The spring-neap variation in vertical shear caused by tidal current is the dominant factor that induces the fort- nightly variation in vertical mixing and thus bottom temperature.

关键词： tidal effect North Yellow Sea Cold Water Mass temperature variation Zhangzi Island thermal front

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Low temperature purification method for the determination of abamectin and ivermectin in edible oils by liquid chromatographytandem mass spectrometry

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Chinese Chemical Letters 2014年第4期25卷 635-639页

作者： Jian-Xiang Huang Da-Hai Lu kai wan Fu-Hua wang Public Monitoring Center for Agro-Product Guangdong Academy of Agricultural Sciences

In this study, a method based on low temperature purification （LTP） coupled with liquid chromatography-tandem mass spectrometry （LC-MS/MS） was developed for the determination of abamectin （ABA） and ivermectin （IVR） in edible oils. ABA and IVR were extracted using conventional liquid-liquid extraction followed by purification via precipitation of interfering fatty components at low temperature without an additional cleanup step. LTP is simple, easy to use, labour-saving and cost effective, and requires reduced amounts of organic solvent. The linear ranges of ABA and IVR were 5- 1000 t^g/L using matrix-matched standards. Limits of detection （LOD） and limits of quantification （LOQ） were in the range of 0.1-0.4 i^g/kg and 0.3-1.3 p^g/kg, respectively. The LOQs were below the strictest maximum residue limits established by Codex Alimentarius Commission. Recoveries at three spiked levels of 10, 20 and 100 i^g/kg in peanut oil, corn oil, olive oil, soybean oil and lard ranged from 71.1% to 119.3% with relative standard deviations of 3.2%-10.3%, which were in agreement with those obtained by the solid phase extraction method. The proposed method was utilized in the analysis of 10 edible oil samples from local market and neither ABA nor IVR was detected. As far as we know, this is the first time that LTP is applied to the determination of avermectins in edible oils.

关键词： Low temperature purification Abamectin Ivermectin Edible oil Liquid chromatography-tandem massspectrometry

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Science Letters:Effect of nitrogen doping on the reduction of nitric oxide with activated carbon in the presence of oxygen

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 113-117页

作者： Xian-kai wan Hui-xiang SHI Xue-quan ZOU Peng GE Da-hui wanG Institute of Environmental Engineering Zhejiang University Hangzhou 310027 China

Nitrogen doping of activated carbon （AC） was performed by annealing both in ammonia and nitric oxide, and the activities of the modified carbons for NO reduction were studied in the presence of oxygen. Results show that nitrogen atoms were incorporated into the carbons, mostly in the form of pyridinic nitrogen or pyridonic nitrogen. The effect of nitrogen doping on the activities of the carbons can be ignored when oxygen is absent, but the doped carbons show desirable activities in the low temperature regime （≤500 ℃） when oxygen is present. The role of the surface nitrogen species is suggested to promote the formation of NO2 in the presence of oxygen, and NO2 can facilitate decomposition of the surface oxygen species in the low temperature regime

关键词： Activated carbon (AC) Nitric oxide Doping Reduction

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Observed characteristics of tidal currents and mean flow in the northern Yellow Sea

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Journal of Oceanology and Limnology 2019年第2期37卷 461-473页

作者： BI Congcong BAO Xianwen DING Yang ZHANG Cong wanG Yu SHEN Biao wan kai College of Oceanic and Atmospheric Sciences Ocean University of China Qingdao 266100 China Physical Oceanography Laboratory/CIMST Ocean University of China and Qingdao National Laboratory for Marine Science and Technology Qingdao 266100 China The First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology Qingdao 266000 China National Marine Environmental Monitoring Center State Oceanic Administration Dalian 116023 China Beihai Off shore Engineering Survey Institute State Oceanic Administration Qingdao 266061 China

Several bottom-mounted Acoustic Doppler Current Profiler (ADCP) moorings were deployed in the northern Yellow Sea (NYS) during the four seasons of 2006–2007 and also the summertime of 2009. A synthesis analysis on the time-continuous records was performed to examine the characteristics and variations of tidal currents and mean flow over the observation period at these stations. Tidal currents accounted for ~75% of the total kinetic energy, with the absolute dominance of M2 constituent. Visible vertical variations of tidal flow were found on all sites, featured by the decrease of amplitude, increase of rotation rate as well as a decreasing trend of the phase for M2 component with depth. A notable exception was in the central NYS, where the maximum tidal currents occurred in the upper or middle layers (~20–40 m) instead of near the surface (<10 m). The observed mean flow was relatively weak, smaller than 15 cm/s. Velocity on the northern end of Yellow Sea Trough (YST) was characterized by low magnitude and an obvious layered structure vertically. In the Bohai Strait (BS) and the northern slope area, the currents weakened and the flow direction presented a major trend to deflect counterclockwise with depth in most observations. Summertime cyclonic circulation around the Yellow Sea Cold Water Mass (YSCWM), its intensification on the frontal zone and the Yellow Sea Warm Current (YSWC) for the winter season were all evident by our direct current measurements. However, the details of water exchange through the BS appeared partly diff erent from the traditionally-accepted pattern. The vertical diff erences of tidal and mean flow were larger in summer than that in winter, implying the influence of thermal structure to the local currents. Aff ected by the water stratification, mean flow usually reached its maximum near the thermocline in spring and summer, while showing a nearly uniform vertical distribution during winter.

关键词： northern Yellow Sea moored current measurements tidal currents mean flow thermal structure

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Temporal-spatial analysis of cyromazine in cowpea using liquid chromatography–mass spectrometry coupled with mass spectrometry imaging

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Food Quality and Safety 2023年第3期7卷 466-473页

作者： Xuemei Tang Congling Huang Jianxiang Huang Jiale wang Zhiting Chen Yan Chen Zemiao Xiao kai wan Institute of Quality Standard and Monitoring Technology for Agro-Products of Guangdong Academy of Agricultural Sciences Key Laboratory of Testing and Evaluation for Agro-Product Safety and Quality(Guangzhou)Ministry of Agriculture and Rural AffairsNational Reference Laboratory for Agricultural Testing(Pesticide Residues)GuangzhouChina

Background:Cowpea(Vigna unguiculata ***.)is an economically important *** is nutritious and popular with ***,it has been listed as one of the agricultural products of critical concern about safety in China and cyromazine is the major risk ***:This study analyzed the dissipation and permeation kinetics of cyromazine residue in cowpea,to offer a scientific basis for the rational use of pesticide and ensure the safety of agricultural *** and methods:The dissipation and residue level of the systemic insecticide cyromazine on cowpea under field and stored conditions were ***,the spatial distribution of cyromazine was studied using mass spectrometry imaging to visualize the dynamic processes of permeation and migration in the tissues post pesticide ***:The dissipation processing of cyromazine in cowpea was shown to follow the first-order kinetics and half-life was 7.76 d in the *** cowpea,the permeation and migration rate of cyromazine was faster than that in kidney beans and accumulation was mainly in the *** is not safe to apply cyromazine to cowpeas with reference to the application method on kidney ***:These findings present vital data for the determination of risks linked with cowpea consumption and pesticide intake.

关键词： Cyromazine cowpea mass spectrometry imaging pesticide residue

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