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Factors contributing to the oxygen concentration over the Qinghai-Tibetan Plateau and its contribution rate calculation

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Science China Earth Sciences 2024年第2期67卷 497-509页

作者： Peijun SHI Ying ZHANG Yanqiang CHEN Wenquan ZHU Xiaokang HU Heyi YANG Lu JIANG yonggui ma Haiping TANG State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Key Laboratory of Environmental Change and Natural Disaster Ministry of EducationBeijing Normal UniversityBeijing100875China The Institute for Disaster management and Reconstruction Sichuan UniversityChengdu610065China Academy of Plateau Science and Sustainability People’s Government of Qinghai Province&Beijing Normal UniversityXining810016China

A decline in atmospheric oxygen concentration is projected in the 21st century given the background of global warming.The Qinghai-Tibetan Plateau is located at a high altitude,and thus,it faces a hypoxia challenge;however,knowledge of the factors contributing to its atmospheric oxygen concentration is still lacking.Here,we conducted joint observations of ecosystem oxygen production and carbon sinks and near-surface atmospheric oxygen concentrations on the Qinghai-Tibetan Plateau and meteorological elements at Beijing Fangshan Station.Using seasonal differences and statistical methods,we calculated the relative contribution rates of vegetation to changes in atmospheric oxygen concentration.Our results indicate that solar radiation,atmospheric humidity,and ecosystem oxygen consumption and production have a significant impact on the atmospheric oxygen concentration,and the impact shows temporal and spatial differences.Vegetation significantly impacts the oxygen concentration,with a contribution rate of 16.7%–24.5%,which is underestimated in existing research.Our findings provide important insights into the factors that influence atmospheric oxygen concentration and highlight the contribution of vegetation.To better understand the oxygen dynamics of the Qinghai-Tibetan Plateau,we recommend further field observations of soil respiration and vegetation photosynthesis to clarify the contributions of carbon storage,carbon sinks and other factors to the near-surface atmospheric oxygen concentration.

关键词： Qinghai-Tibetan Plateau Oxygen concentration Relative contribution rate Air temperature Vegetation

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Upper ocean near-inertial response to the passage of two sequential typhoons in the northwestern South China Sea

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Science China Earth Sciences 2019年第5期62卷 863-871页

作者： yonggui ma Shuwen ZHANG Yiquan QI Zhiyou JING College of Ocean and Meteorology Guangdong Ocean University Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology College of Oceanography Hohai University State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences

Fifty-seven days of moored current records are examined, focusing on the sequential passage of Typhoons Nesat and Nalgae separated by 5 days in the northwestern South China Sea. Both typhoons generated strong near-inertial waves(NIW) as detected by a moored array, with the near-inertial velocity to the right of the typhoon path significantly larger than to the left. The estimated vertical phase and group velocities of the NIW induced by Typhoon Nesat are 0.2 cm s^(-1) and 0.85 m h^(-1), respectively,corresponding to a vertical wavelength of 350 m. Both the vertical phase and group velocities of the NIW induced by Typhoon Nalgae are lower than those of Typhoon Nesat, with the corresponding vertical wavelength only one-half that of Nesat. The threshold values of induced near-inertial kinetic energy(NIKE) of 5 J m^(-3) reach water depths of 300 and 200 m for Typhoons Nesat and Nalgae, respectively, illustrating that the NIKE induced by Typhoon Nesat dissipated less with depth. Obvious blueshifts in the induced NIW frequencies are also detected. The frequency of NIW induced by Typhoon Nesat significantly increases at water depths of 100–150 m because of Doppler shifting, but decreases significantly at water depths of 100–150 m for Nalgae because of the greater influence of the background vorticity during the passage of Typhoon Nalgae.

关键词： Typhoon Nesat Typhoon Nalgae Near-inertial waves Near-inertial kinetic energy Inertial wave propagation

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Infl uence of sequential tropical cyclones on phytoplankton blooms in the northwestern South China Sea

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Journal of Oceanology and Limnology 2021年第1期39卷 14-25页

作者： Tongyu WANG Shuwen ZHANG Fajin CHEN yonggui ma Chen JIANG Jie YU College of Oceanography and Meteorology Guangdong Ocean UniversityZhanjiang 524000China Institute of marine Science Shantou UniversityShantou 515063China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266000China

Upper ocean responses to the passage of sequential tropical cyclones over the northwestern South China Sea(SCS)in 2011 were investigated using satellite remote sensing data,Argo reanalysis data,and an array of mooring data.We found that the sea surface low temperature region lasted for more than 38 days and two phytoplankton blooms occurred after the passage of sequential tropical cyclones.The upper ocean cooling reached 2–5°C with a right-side bias was observed along the typhoon track to about 200 km.The maintenance of low temperature region and the two phytoplankton blooms were mainly driven by upwelling and near-inertial turbulence mixing induced by the sequential tropical cyclones.The fi rst phytoplankton bloom appeared on the 7 th day after the passage of the three tropical cyclones,and the chlorophyll-a(chl-a)concentration increased by 226%,which may be mainly driven by typhoons induced upwelling.The second phytoplankton bloom occurred on the 30 th day,the chl-a concentration increased by 290%.Further analysis suggested that only the typhoons with similar characteristics as Nesat and Nalgae can induce strong near-inertial oscillation(NIO).Strong turbulent mixing associated with the near-inertial baroclinic shear instability lasted for 26 days.The measured mean eddy diff usivity in the upper ocean was above 10-4 m 2/s after typhoon Nesat.Enhancement of the turbulent mixing in the upper ocean helped to transport nutrient-rich cold waters from the deep layer to the euphotic layer,and is a major mechanism for the long-term maintenance of low temperature region as well as the second phytoplankton bloom.

关键词： sequential tropical cyclones two phytoplankton blooms tropical cyclones induced upwelling turbulence mixing by the near-inertial baroclinic shear instability

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聚丙烯熔喷空气过滤材料表面仿生改性及性能

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高分子材料科学与工程 2024年第2期40卷 141-150页

作者：马文龙郝天煦张威王新亚李永贵陈明星河北科技大学纺织服装学院河北石家庄050018 福建省新型功能性纺织纤维及材料重点实验室(闽江学院) 福建福州350108

聚丙烯(PP)熔喷空气过滤材料的抗菌性能较差,细菌、霉菌等微生物会寄生于材料表面。文中利用仿生改性法,以单宁酸(TA)为抗菌改性剂、CuSO_(4)/H_(2)O_(2)为促进剂制备了具有优异抗菌性能的PP/TA熔喷空气过滤材料。分析讨论了TA改性溶液... 详细信息

聚丙烯(PP)熔喷空气过滤材料的抗菌性能较差,细菌、霉菌等微生物会寄生于材料表面。文中利用仿生改性法,以单宁酸(TA)为抗菌改性剂、CuSO_(4)/H_(2)O_(2)为促进剂制备了具有优异抗菌性能的PP/TA熔喷空气过滤材料。分析讨论了TA改性溶液浓度和CuSO_(4)/H_(2)O_(2)促进剂的加入对PP/TA熔喷空气过滤材料结构与性能的影响。结果表明,CuSO_(4)/H_(2)O_(2)促进剂的加入将TA改性时间从24 h缩短至40 min,并增强了PP/TA熔喷空气过滤材料的改性牢度。当TA浓度为6 g/L时,PP/TA熔喷空气过滤材料相较于PP熔喷空气过滤材料其过滤效率和压降分别提升了2.7%和4 Pa,水接触角降低了17.5°;且TA改性对PP熔喷空气过滤材料的驻极性能并无影响,驻极后PP/TA熔喷过滤材料的过滤效率为95.56%,压降为38 Pa,且具备良好的抗菌性能。同时,CuSO_(4)/H_(2)O_(2)促进剂的加入在材料表面引入了Cu^(2+),增强了抗菌效果。

关键词：聚丙烯熔喷材料单宁酸仿生改性空气过滤性能抗菌性能

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Alloying engineering for thermoelectric performance enhancement in p-type skutterudites with synergistic carrier concentration optimization and thermal conductivity reduction

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Journal of Advanced Ceramics 2023年第3期12卷 539-552页

作者： Zhiyuan Liu yonggui Wang Ting Yang Zuju ma Huiyan Zhang Hailing Li Ailin Xia Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal materials Ministry of EducationAnhui University of TechnologyMaanshan 243002China School of materials Science and Engineering Anhui University of TechnologyMaanshan 243002China School of Environmental and materials Engineering Yantai UniversityYantai 264005China

The enhancements in thermoelectric(TE)performances of p-type skutterudites are usually limited due to the relatively low Seebeck coefficients owing to the higher carrier concentration and more impurity phases induced by inherent structural instability of a Fe-based skutterudite.As shown in this study,alloying engineering of Ni doping at Fe sites in a p-type CeFe_(3.8)Co_(0.2)Sb_(12)skutterudite can not only reduce the impurity phases with high thermal conductivity but also regulate the carrier concentration,and thus significantly increase the Seebeck coefficient.The thermal conductivity was largely suppressed due to the enhanced point defect phonon scattering and decreased hole concentration.As a result,a TE figure of merit ZT of the CeFe_(3.5)Ni_(0.3)Co_(0.2)Sb_(12)sample reached 0.8,which is approximately 50%higher than that of a Ni-free sample.Appropriate Ni doping can maintain a high ZT at a high temperature by controlling the reduction in a band gap.Therefore,a high average ZT close to 0.8 at 650–800 K for CeFe_(3.5)Ni_(0.3)Co_(0.2)Sb_(12)was obtained,which was comparable to or even higher than those of the reported Ce-filled Fe-based skutterudites due to the synergistic optimization of electrical and thermal performances.This study provides a strategy to synergistically optimize electrical–thermal performances of the p-type skutterudites by alloying engineering.

关键词： p-type skutterudite materials Ni doping synergistic optimization thermoelectric(TE)properties

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Improving long-term temperature bias stability of an integrated optical gyroscope employing a Si_(3)N_(4)resonator

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Photonics Research 2022年第7期10卷 1661-1668页

作者： CHANGKUN FENG yonggui ZHANG HONGHAO ma HUI LI LISHUANG FENG School of Instrumentation and Optoelectronics Engineering Beihang UniversityBeijing 100191China

The presence of polarization noise generated by the waveguide resonator limits the performance of a resonant integrated optical gyroscope(RIOG).Using silicon nitride(Si_(3)N_(4))to fabricate a waveguide with an ultralowaspect-ratio can result in a resonator that only supports light transmission in a single-polarization state,suppressing polarization noise.We successfully fabricated a Si_(3)N_(4)resonator with a bending radius of 17.5 mm,a finesse(F)of 150,a quality factor(Q)of 1.54×10^(7),and a propagation loss of 1.2 d B/m.The Si_(3)N_(4)resonator was used to construct a double closed-loop RIOG that showed long-term bias stability(3600 s)of 13.2°/h at room temperature,14.8°/h at 40℃,21.2°/h at 50℃,and 23.6°/h at 60℃.We believe this to be the best performance reported to date for a Si_(3)N_(4)resonator-based RIOG.This advancement paves the way for the wider application of RIOGs.

关键词： resonator polarization waveguide

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Energy band and charge-carrier engineering in skutterudite thermoelectric materials

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Chinese Physics B 2022年第10期31卷 208-219页

作者：刘志愿杨婷王永贵夏爱林马连波 Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal materials(Ministry of Education) Anhui University of TechnologyMaanshan 243002China School of materials Science and Engineering Anhui University of TechnologyMaanshan 243002China

The binary CoSb_(3) skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit, ZT, is very low. The thermal conductivity of CoSb_(3) materials can be significantly reduced through phonon engineering, such as low-dimensional structure, the introduction of nano second phases,nanointerfaces or nanopores, which greatly improves their ZT values. The phonon engineering can optimize significantly the thermal transport properties of CoSb_(3)-based materials. However, the improvement of the electronic transport properties is not obvious, or even worse. Energy band and charge-carrier engineering can significantly improve the electronic transport properties of CoSb_(3)-based materials while optimizing the thermal transport properties. Therefore, the decoupling of thermal and electronic transport properties of CoSb_(3)-based materials can be realized by energy band and charge-carrier engineering. This review summarizes some methods of optimizing synergistically the electronic and thermal transport properties of CoSb_(3) materials through the energy band and charge-carrier engineering strategies. Energy band engineering strategies include band convergence or resonant energy levels caused by doping/filling. The charge-carrier engineering strategy includes the optimization of carrier concentration and mobility caused by doping/filling, forming modulation doped structures or introducing nano second phase. These strategies are effective means to improve performance of thermoelectric materials and provide new research ideas of development of high-efficiency thermoelectric materials.

关键词： CoSb_(3)-based skutterudite materials energy band engineering charge-carrier engineering thermoelectric properties

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Built‑In Electric Field‑Driven Ultrahigh‑Rate K‑Ion Storage via Heterostructure Engineering of Dual Tellurides Integrated with Ti_(3)C_(2)T_(x)MXene

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纳微快报:英文版 2023年第12期15卷 127-140页

作者： Long Pan Rongxiang Hu Yuan Zhang Dawei Sha Xin Cao Zhuoran Li yonggui Zhao Jiangxiang Ding Yaping Wang ZhengMing Sun Key Laboratory of Advanced Metallic materials of Jiangsu Province School of Materials Science and EngineeringSoutheast UniversityNanjing 211189People’s Republic of China Department of Chemistry University of ZurichWinterthurerstrasse 190CH‑8057 ZurichSwitzerland School of materials Science and Engineering Anhui University of TechnologyMa’anshan 243002AnhuiPeople’s Republic of China

Exploiting high-rate anode materials with fast K+diffusion is intriguing for the development of advanced potassium-ion batteries(KIBs)but remains unrealized.Here,heterostructure engineering is proposed to construct the dual transition metal tellurides(CoTe_(2)/ZnTe),which are anchored onto two-dimensional(2D)Ti_(3)C_(2)T_(x)MXene nanosheets.Various theoretical modeling and experimental findings reveal that heterostructure engineering can regulate the electronic structures of CoTe_(2)/ZnTe interfaces,improving K+diffusion and adsorption.In addition,the different work functions between CoTe_(2)/ZnTe induce a robust built-in electric field at the CoTe_(2)/ZnTe interface,providing a strong driving force to facilitate charge transport.Moreover,the conductive and elastic Ti_(3)C_(2)T_(x)can effectively promote electrode conductivity and alleviate the volume change of CoTe_(2)/ZnTe heterostructures upon cycling.Owing to these merits,the resulting CoTe_(2)/ZnTe/Ti_(3)C_(2)T_(x)(CZT)exhibit excellent rate capability(137.0 mah g^(-1)at 10 A g^(-1))and cycling stability(175.3 mah g^(-1)after 4000 cycles at 3.0 A g^(-1),with a high capacity retention of 89.4%).More impressively,the CZT-based full cells demonstrate high energy density(220.2 Wh kg^(-1))and power density(837.2 W kg^(-1)).This work provides a general and effective strategy by integrating heterostructure engineering and 2D material nanocompositing for designing advanced high-rate anode materials for next-generation KIBs.

关键词： Transition metal tellurides Heterostructures Built-in electric field Potassium-ion batteries Anode material

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The uptake diversity of soil nitrogen nutrients by main plant species in Kobresia humilis alpine meadow on the Qinghai-Tibet Plateau

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Science China Earth Sciences 2012年第10期55卷 1688-1695页

作者： WANG WenYing ma yonggui XU Jin WANG HuiChun ZHU JinFu ZHOU HuaKun Department of Life and Geography Sciences Qinghai Normal University Xining 810008 China Northwest Institute of Plateau Biology Chinese Academy of Sciences Xining 810008 China Center for Agricultural Resources Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences Shijiazhuang 050021 China

We studied the uptake of ammonium,nitrate,and a variety of amino acids by alpine plant species in the Kobresia humilis alpine meadow ecosystem in situ.We examined the extent of niche separation in uptake of N source by different plant species in alpine communities,and investigated the contribution of symbiotically fixed N to the total N in alpine meadow.The results are(1) δ 15 N natural abundance values of 13 plant species lie between 2.680‰ and 5.169‰,and the scope is 7.849‰.(2) Leguminous plants,such as Trigonella ruthenica,Gueldenstaedtia diversiffolia,and Oxytyopis ochrocephala,and non-leguminous plant Gentiana straminea uptake low amounts of 15 N labeled ammonium,nitrate,glycine or aspartate in soil.(3) As far as the plant uptake of organic N is concerned,Kobresia humilis,Poa pratensis,and Gentiuna spathutifolta can effectively uptake organic nitrogen,and about 37%-40% of the nitrogen of these species comes from soil organic nitrogen sources(such as glycine and aspartate).Stipa aliena can effectively uptake nitrate,and 60% of its nitrogen comes from soil nitrate.Potentilla anserina,Poa pratensis,and Thalictrum alpinum can effectively absorb ammonium in comparason to other plant species in the meadow,and about 25%-27% of the nitrogen in these plants comes from soil ammonium.(4) The contribution of leguminous fixed N to total N is 7.48%-9.26% in Kobresia humilis alpine meadow.(5) These data show many plant species of alpine meadow may effectively utilize dissolved organic nitrogen such as amino acids,and these plants have diverse ways to uptake soil nitrogen in alpine meadows.Based on the results we can partly explain why there are abundant biodiversities and how plants at alpine habitat utilize the limited soil N sources.

关键词：高寒草甸生态系统土壤有机氮植物吸收氮素养分矮嵩草物种多样性青藏高原土壤硝酸盐

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盐碱演化环境下高压实GMZ膨润土膨胀变形特性

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岩土工程学报 2023年第4期45卷 690-698页

作者：陈永贵刘聪马婧孙曌叶为民王琼同济大学岩土及地下工程教育部重点实验室上海200092 同济大学土木工程学院地下建筑与工程系上海200092

高放射性废物深地质处置库中,混凝土材料在地下水和辐射热的长期耦合作用下,不断衰解生成高碱性物质,进而影响高压实膨润土的膨胀变形特性,危及处置库运行安全。针对中国北山处置场地下水特征对缓冲/回填材料高压实高庙子(GMZ)膨润土变... 详细信息

高放射性废物深地质处置库中,混凝土材料在地下水和辐射热的长期耦合作用下,不断衰解生成高碱性物质,进而影响高压实膨润土的膨胀变形特性,危及处置库运行安全。针对中国北山处置场地下水特征对缓冲/回填材料高压实高庙子(GMZ)膨润土变形特性的影响,分别配制北山地下水(BSW)、早期混凝土衰解液(YCW)和后期混凝土衰解液(ECW),开展了盐碱演化环境下高压实GMZ膨润土的一维膨胀变形试验,获取了初试干密度(1.50,1.60,1.70,1.80 g/cm^(3))和上覆荷载(0.1,0.2,0.4 MPa)对膨润土变形的影响规律。结果表明:随着BSW、YCW和ECW 3种溶液相继入渗,高压实膨润土的稳定膨胀变形率不断增加,但增加值逐渐减小;当YCW和ECW入渗时,稳定膨胀变形率的增加值随干密度增加而减小,随荷载增大而减小。基于压汞试验结果,阐明了盐碱演化环境下高压实膨润土持续膨胀的微观机理。研究成果可为中国处置库缓冲/回填材料的选择和工程屏障设计提供依据。

关键词： GMZ膨润土膨胀变形盐碱演化环境干密度上覆荷载

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