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Engineering Strategies for Suppressing the Shuttle Effect in Lithium–Sulfur Batteries 被引量:2
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作者 Jiayi Li Li Gao +7 位作者 Fengying Pan Cheng Gong Limeng Sun Hong Gao jinqiang zhang Yufei Zhao Guoxiu Wang Hao Liu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第1期187-221,共35页
Lithium–sulfur(Li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-elect... Lithium–sulfur(Li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value.Many methods were proposed for inhibiting the shuttle effect of polysulfide,improving corresponding redox kinetics and enhancing the integral performance of Li–S batteries.Here,we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of Li–S batteries.First,the electrochemical principles/mechanism and origin of the shuttle effect are described in detail.Moreover,the efficient strategies,including boosting the sulfur conversion rate of sulfur,confining sulfur or lithium polysulfides(LPS)within cathode host,confining LPS in the shield layer,and preventing LPS from contacting the anode,will be discussed to suppress the shuttle effect.Then,recent advances in inhibition of shuttle effect in cathode,electrolyte,separator,and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for Li–S batteries.Finally,we present prospects for inhibition of the LPS shuttle and potential development directions in Li–S batteries. 展开更多
关键词 Shuttle effect Designed strategies Li-S battery Lithium polysulfides
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Comparison between ozonesonde measurements and satellite retrievals over Beijing,China 被引量:2
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作者 jinqiang zhang Yuejian Xuan +5 位作者 Jianchun Bian Holger Vomel Yunshu Zeng Zhixuan Bai Dan Li Hongbin Chen 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第1期14-20,共7页
从2013年开始,作者团队使用自主研发电化学原理臭氧探空仪在华北平原北京地区进行每周一次观测.本研究首次使用2013-2019年期间北京地区臭氧探空数据评估Aqua卫星搭载大气红外探测仪(AIRS)和Aura卫星搭载微波临边探测器(MLS)反演垂直臭... 从2013年开始,作者团队使用自主研发电化学原理臭氧探空仪在华北平原北京地区进行每周一次观测.本研究首次使用2013-2019年期间北京地区臭氧探空数据评估Aqua卫星搭载大气红外探测仪(AIRS)和Aura卫星搭载微波临边探测器(MLS)反演垂直臭氧廓线,并对比臭氧探空,AIRS和Aura卫星搭载臭氧监测仪(OMI)臭氧柱总量结果.尽管臭氧探空与卫星反演垂直臭氧廓线在局部高度处差异较大,但整体来说两者较为接近(相对偏差大多<10%).臭氧探空,AIRS和OMI三种仪器测量臭氧柱总量的年变化特征较为一致,其年均臭氧柱总量分别为351.8±18.4 DU,348.8±19.5 DU和336.9±14.2 DU.后续对国内多站点观测数据分析将有助于进一步理解臭氧探空与卫星反演臭氧资料在不同区域的一致性. 展开更多
关键词 臭氧探空 卫星反演 垂直臭氧廓线 臭氧柱总量 华北平原
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Electrochemical Carbon Dioxide Reduction to Ethylene:From Mechanistic Understanding to Catalyst Surface Engineering 被引量:4
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作者 Junpeng Qu Xianjun Cao +7 位作者 Li Gao Jiayi Li Lu Li Yuhan Xie Yufei Zhao jinqiang zhang Minghong Wu Hao Liu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第10期382-415,共34页
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)provides a promising way to convert CO_(2)to chemicals.The multicarbon(C_(2+))products,especially ethylene,are of great interest due to their versatile indust... Electrochemical carbon dioxide reduction reaction(CO_(2)RR)provides a promising way to convert CO_(2)to chemicals.The multicarbon(C_(2+))products,especially ethylene,are of great interest due to their versatile industrial applications.However,selectively reducing CO_(2)to ethylene is still challenging as the additional energy required for the C–C coupling step results in large overpotential and many competing products.Nonetheless,mechanistic understanding of the key steps and preferred reaction pathways/conditions,as well as rational design of novel catalysts for ethylene production have been regarded as promising approaches to achieving the highly efficient and selective CO_(2)RR.In this review,we first illustrate the key steps for CO_(2)RR to ethylene(e.g.,CO_(2)adsorption/activation,formation of~*CO intermediate,C–C coupling step),offering mechanistic understanding of CO_(2)RR conversion to ethylene.Then the alternative reaction pathways and conditions for the formation of ethylene and competitive products(C_1 and other C_(2+)products)are investigated,guiding the further design and development of preferred conditions for ethylene generation.Engineering strategies of Cu-based catalysts for CO_(2)RR-ethylene are further summarized,and the correlations of reaction mechanism/pathways,engineering strategies and selectivity are elaborated.Finally,major challenges and perspectives in the research area of CO_(2)RR are proposed for future development and practical applications. 展开更多
关键词 Key steps in CO_(2)RR-ethylene Preferable reaction pathways Mechanism understanding Surface engineering strategies of Cu-based catalysts
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Two-dimensional nanomaterials confined single atoms: New opportunities for environmental remediation 被引量:1
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作者 Yu Yin Lei Shi +4 位作者 Shu zhang Xiaoguang Duan jinqiang zhang Hongqi Sun Shaobin Wang 《Nano Materials Science》 EI CAS CSCD 2023年第1期15-38,共24页
Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and stor... Two-dimensional(2D)supports confined single-atom catalysts(2D SACs)with unique geometric and electronic structures have been attractive candidates in different catalytic applications,such as energy conversion and storage,value-added chemical synthesis and environmental remediation.However,their environmental appli-cations lack of a comprehensive summary and in-depth discussion.In this review,recent progresses in synthesis routes and advanced characterization techniques for 2D SACs are introduced,and a comprehensive discussion on their applications in environmental remediation is presented.Generally,2D SACs can be effective in catalytic elimination of aqueous and gaseous pollutants via radical or non-radical routes and transformation of toxic pollutants into less poisonous species or highly value-added products,opening a new horizon for the contami-nant treatment.In addition,in-depth reaction mechanisms and potential pathways are systematically discussed,and the relationship between the structure-performance is highlighted.Finally,several critical challenges within this field are presented,and possible directions for further explorations of 2D SACs in environmental remediation are suggested.Although the research of 2D SACs in the environmental application is still in its infancy,this review will provide a timely summary on the emerging field,and would stimulate tremendous interest for designing more attractive 2D SACs and promoting their wide applications. 展开更多
关键词 Single-atom catalysis Two-dimensional material Advanced oxidation process Degradation Transformation Industrial wastewater
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Value-Added Products Derived from 15 Years of High-Quality Surface Solar Radiation Measurements at Xianghe,a Suburban Site in the North China Plain
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作者 Mengqi LIU Xuehua FAN +2 位作者 Xiang'ao XIA jinqiang zhang Jun LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第6期1132-1141,共10页
Surface solar radiation(SSR) is a key component of the energy budget of the Earth’s surface, and it varies at different spatial and temporal scales. Considerable knowledge of how and why SSR varies is crucial to a be... Surface solar radiation(SSR) is a key component of the energy budget of the Earth’s surface, and it varies at different spatial and temporal scales. Considerable knowledge of how and why SSR varies is crucial to a better understanding of climate change, which surely requires long-term measurements of high quality. The objective of this study is to introduce a value-added SSR dataset from Oct 2004 to Oct 2019 based on measurements taken at Xianghe, a suburban site in the North China Plain;two value-added products based on the 1-minute SSR measurements are developed. The first is clear sky detection by using a machine learning model. The second is cloud fraction estimation derived from an effective semiempirical method. A “brightening” of global horizontal irradiance(GHI) was revealed and found to occur under both clear and cloudy conditions. This could likely be attributed to a reduction in aerosol loading and cloud fraction. This dataset could not only improve our knowledge of the variability and trend of SSR in the North China Plain, but also be beneficial for solar energy assessment and forecasting. 展开更多
关键词 surface solar radiation clear sky detection cloud fraction North China Plain
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Intrinsic Mechanisms of Morphological Engineering and Carbon Doping for Improved Photocatalysis of 2D/2D Carbon Nitride Van Der Waals Heterojunction
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作者 jinqiang zhang Xiaoli Zhao +10 位作者 Lin Chen Shuli Li Haijun Chen Yuezhao Zhu Shuaijun Wang Yang Liu Huayang zhang Xiaoguang Duan Mingbo Wu Shaobin Wang Hongqi Sun 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第3期96-106,共11页
Van der Waals(VDW)heterojunctions in a 2D/2D contact provide the highest area for the separation and transfer of charge carriers.In this work,a top-down strategy with a gas erosion process was employed to fabricate a ... Van der Waals(VDW)heterojunctions in a 2D/2D contact provide the highest area for the separation and transfer of charge carriers.In this work,a top-down strategy with a gas erosion process was employed to fabricate a 2D/2D carbon nitride VDW heterojunction in carbon nitride(g-C_(3)N_(4))with carbon-rich carbon nitride.The created 2D semiconducting channel in the VDW structure exhibits enhanced electric field exposure and radiation absorption,which facilitates the separation of the charge carriers and their mobility.Consequently,compared with bulk g-C_(3)N_(4)and its nanosheets,the photocatalytic performance of the fabricated carbon nitride VDW heterojunction in the water splitting reaction to hydrogen is improved by 8.6 and 3.3 times,respectively,while maintaining satisfactory photo-stability.Mechanistically,the finite element method(FEM)was employed to evaluate and clarify the contributions of the formation of VDW heterojunction to enhanced photocatalysis,in agreement quantitatively with experimental ones.This study provides a new and effective strategy for the modification and more insights to performance improvement on polymeric semiconductors in photocatalysis and energy conversion. 展开更多
关键词 carbon nitride Van der Waals heterojunctions enhanced electric field exposure improved radiation absorption photocatalytic water splitting promoted dynamics of charge carriers
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The Nature of Active Sites for Plasmon-Mediated Photothermal Catalysis and Heat-Coupled Photocatalysis in Dry Reforming of Methane
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作者 jinqiang zhang Liang Wang +15 位作者 Xiaoli Zhao Lei Shi Haijun Chen Shu zhang Peng zhang Shuaijun Wang Laichang zhang Yinfeng Wang Xiaoyuan Wang Yuezhao Zhu Huayang zhang Xiaoguang Duan Mingbo Wu Guosheng Shao Shaobin Wang Hongqi Sun 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第5期381-388,共8页
Solar energy-induced catalysis has been attracting intensive interests and its quantum efficiencies in plasmon-mediated photothermal catalysis(P-photothermal catalysis)and external heat-coupled photocatalysis(E-photot... Solar energy-induced catalysis has been attracting intensive interests and its quantum efficiencies in plasmon-mediated photothermal catalysis(P-photothermal catalysis)and external heat-coupled photocatalysis(E-photothermal catalysis)are ultimately determined by the catalyst structure for photo-induced energetic hot carriers.Herein,different catalysts of supported(TiO_(2)-P25 and Al_(2)O_(3))platinum quantum dots are employed in photo,thermal,and photothermal catalytic dry reforming of methane.Integrated experimental and computational results unveil different active sites(hot zones)on the two catalysts for photo,thermal,and photothermal catalysis.The hot zones of P-photothermal catalysis are identified to be the metal-support interface on Pt/P25 and the Pt surface on Pt/Al_(2)O_(3),respectively.However,a change of the active site to the Pt surface on Pt/P25 is for the first time observed in E-photothermal catalysis(external heating temperature of 700℃).The hot zones contribute to the significant enhancements in photothermal catalytic reactivity against thermocatalysis.This study helps to understand the reaction mechanism of photothermal catalysis to exploit efficient catalysts for solar energy utilization and fossil fuels upgrading. 展开更多
关键词 dry reforming of methane hot zones photothermal catalysis platinum-based catalysts
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Earth Summit Mission 2022:Scientific Expedition and Research on Mt.Qomolangma Helps Reveal the Synergy between Westerly Winds and Monsoon and the Resulting Climatic and Environmental Effects
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作者 Yaoming MA Weiqiang MA +22 位作者 Huaguang DAI Lei zhang Fanglin SUN jinqiang zhang Nan YAO Jianan HE Zhixuan BAI Yuejian XUAN Yunshuai zhang Yuan YUAN Chenyi YANG Weijun SUN Ping ZHAO Minghu DING Kongju ZHU Jie HU Bian Bazhuga Bai Juepingcuo Zhuo Ma Ren Qingnima Suo Langwangdui Yang Zong Haikun WEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第2期187-193,共7页
“Earth summit mission 2022”is one of the landmark scientific research activities of the Second Tibetan Plateau Scientific Expedition and Research(STEP).This scientific expedition firstly used advanced technology and... “Earth summit mission 2022”is one of the landmark scientific research activities of the Second Tibetan Plateau Scientific Expedition and Research(STEP).This scientific expedition firstly used advanced technology and methods to detect vertical meteorological elements and produce forecasts for mountain climbing.The“Earth summit mission 2022”Qomolangma scientific expedition exceeded an altitude of over 8000 meters for the first time and carried out a comprehensive scientific investigation mission on the summit of Mt.Qomolangma.Among the participants,the westerly–monsoon synergy and influence team stationed in the Mt.Qomolangma region had two tasks:1)detecting the vertical structure of the atmosphere for parameters such as wind,temperature,humidity,and pressure with advanced instruments for high-altitude detection at the Mt.Qomolangma base camp;and 2)observing extreme weather processes to ensure that members of the mountaineering team could successfully reach the top.Through this scientific expedition,a better understanding of the vertical structure and weather characteristics of the complex area of Mt.Qomolangma is gained. 展开更多
关键词 EARTH ALTITUDE weather
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Dynamic and Thermodynamic Features of Low and Middle Clouds Derived from Atmospheric Radiation Measurement Program Mobile Facility Radiosonde Data at Shouxian, China 被引量:7
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作者 jinqiang zhang Hongbin CHEN +1 位作者 Xiang'ao XIA Wei-Chyung WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第1期21-33,共13页
By using the radiosonde measurements collected at Shouxian,China,we examined the dynamics and thermodynamics of single- and two-layer clouds formed at low and middle levels.The analyses indicated that the horizontal w... By using the radiosonde measurements collected at Shouxian,China,we examined the dynamics and thermodynamics of single- and two-layer clouds formed at low and middle levels.The analyses indicated that the horizontal wind speed above the cloud layers was higher than those within and below cloud layers.The maximum balloon ascent speed(5.3 m s^-1) was located in the vicinity of the layer with the maximum cloud occurrence frequency(24.4%),indicating an upward motion(0.1-0.16 ms^-1).The average thickness,magnitude and gradient of the temperature inversion layer above single-layer clouds were117±94 m,1.3±1.3℃ and 1.4±1.5℃(100 m)^-1,respectively.The average temperature inversion magnitude was the same(1.3℃) for single-low and single-middle clouds;however,a larger gradient[1.7±1.8℃(100 m)^-1]and smaller thickness(94±67 m) were detected above single-low clouds relative to those above single-middle clouds[0.9±0.7℃(100 m)^-1 and157±120 m].For the two-layer cloud,the temperature inversion parameters were 106±59 m,1.0±0.9℃ and 1.0±1.0℃(100 m)^-1 above the upper-layer cloud and 82 ± 60 m,0.6±0.9℃ and 0.7±0.6℃(100 m)^-1 above the low-layer cloud.Absolute differences between the cloud-base height(cloud-top height) and the lifting condensation level(equilibrium level)were less than 0.5 km for 66.4%(36.8%) of the cases analyzed in summer. 展开更多
关键词 RADIOSONDE cloud dynamics THERMODYNAMICS
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Analysis of Low-level Temperature Inversions and Their Effects on Aerosols in the Lower Atmosphere 被引量:2
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作者 Jun LI Hongbin CHEN +4 位作者 Zhanqing LI Pucai WANG Xuehua FAN Wenying HE jinqiang zhang 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第11期1235-1250,共16页
High-quality and continuous radiosonde, aerosol and surface meteorology datasets are used to investigate the statistical characteristics of meteorological parameters and their effects on aerosols. The data were collec... High-quality and continuous radiosonde, aerosol and surface meteorology datasets are used to investigate the statistical characteristics of meteorological parameters and their effects on aerosols. The data were collected at the Atmospheric Radiation Measurement Southern Great Plains climate research facility during 2000–15. The parameters and vertical distribution of temperature inversion layers were found to have strong diurnal and seasonal changes. For surface-based temperature inversion (SBI), the mean frequency and depth of temperature inversion layers were 39.4% and 198 m, respectively. The temperature difference between the top and bottom of SBI was 4.8℃, and so the temperature gradient was 2.4℃(100 m)^-1. The detailed vertical distributions of temperature inversion had been determined, and only the temperature inversion layers below 1000 m showed diurnal and seasonal variations. Mean surface aerosol number concentrations increased by 43.0%, 21.9% and 49.2% when SBIs were present at 0530, 1730 and 2330 LST, respectively. The effect of SBI on surface aerosol concentration was weakest in summer (18.1%) and strongest in winter (58.4%). During elevated temperature inversion events, there was no noticeable difference in surface aerosol number concentrations. Temperature differences and temperature gradients across SBIs correlated fairly well with aerosol number concentrations, especially for temperature gradients. The vertical distribution of aerosol optical properties with and without temperature inversions was different. Surface aerosol measurements were representative of the air within (below), but not above, SBIs and EIs. These results provide a basis for developing a boundary layer aerosol accumulation model and for improving radiative transfer models in the lower atmosphere. 展开更多
关键词 temperature INVERSION AEROSOL LOWER ATMOSPHERE VERTICAL distribution
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Intensive Radiosonde Measurements of Summertime Convection over the Inner Mongolia Grassland in 2014:Difference between Shallow Cumulus and Other Conditions 被引量:2
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作者 Hongrong SHI Hongbin CHEN +4 位作者 Xiang'ao XIA Xuehua FAN jinqiang zhang Jun LI Chao LING 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第6期783-790,共8页
Using radiosonde measurements from 26 July to 30 July 2014 at Baiqi over the Inner Mongolia grassland of China, the vertical structure of shallow cumulus (SCu) clouds and associated environmental conditions were inv... Using radiosonde measurements from 26 July to 30 July 2014 at Baiqi over the Inner Mongolia grassland of China, the vertical structure of shallow cumulus (SCu) clouds and associated environmental conditions were investigated. The cloud base height and the cloud top height of SCu was 3.4 km and 5 km, respectively. The temperature of the SCu layer was less than 0℃. The horizontal advection of specific humidity was smaller than the vertical transport in the atmosphere below 5 km. Above 5 km, the thermodynamic structure of the atmosphere remained stable. At the interface of the cloud layer and free air atmosphere, there was obvious wind shear and a temperature inversion (-2.9~C). Comparisons of environmental parameters associated with cumulus congestus, rain and clear days, showed that the formation of SCu was characterized by a higher Bowen ratio (high sensible heat flux and low latent heat flux), which indicated intensive turbulence in the boundary layer. The formation of SCu was associated with the boundary layer height exceeding the lifting condensation level. The maintenance of SCu was likely associated with the lower convective available potential energy, weak wind shear, and weak subsidence of the synoptic system, which did not favor the dramatic vertical development of SCu and thereby the transformation of SCu to cumulus congestus. 展开更多
关键词 shallow cumulus sounding measurement environmental parameter Inner Mongolia grassland
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A multi-location joint field observation of the stratosphere and troposphere over the Tibetan Plateau 被引量:2
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作者 jinqiang zhang Yi Liu +11 位作者 HongBin Chen ZhaoNan Cai ZhiXuan Bai LingKun Ran Tao Luo Jing Yang YiNan Wang YueJian Xuan YinBo Huang XiaoQing Wu JianChun Bian DaRen Lu 《Earth and Planetary Physics》 CSCD 2019年第2期87-92,共6页
The unique geographical location and high altitude of the Tibetan Plateau can greatly influence regional weather and climate.In particular, the Asian summer monsoon(ASM) anticyclone circulation system over the Tibetan... The unique geographical location and high altitude of the Tibetan Plateau can greatly influence regional weather and climate.In particular, the Asian summer monsoon(ASM) anticyclone circulation system over the Tibetan Plateau is recognized to be a significant transport pathway for water vapor and pollutants to enter the stratosphere. To improve understanding of these physical processes, a multi-location joint atmospheric experiment was performed over the Tibetan Plateau from late July to August in 2018, funded by the fiveyear(2018–2022) STEAM(stratosphere and troposphere exchange experiment during ASM) project, during which multiple platforms/instruments—including long-duration stratospheric balloons, dropsondes, unmanned aerial vehicles, special sounding systems, and ground-based and satellite-borne instruments—will be deployed. These complementary methods of data acquisition are expected to provide comprehensive atmospheric parameters(aerosol, ozone, water vapor, CO_2, CH_4, CO, temperature, pressure,turbulence, radiation, lightning and wind); the richness of this approach is expected to advance our comprehension of key mechanisms associated with thermal, dynamical, radiative, and chemical transports over the Tibetan Plateau during ASM activity. 展开更多
关键词 TIBETAN PLATEAU Asian summer MONSOON STRATOSPHERE and troposphere exchange
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Controllable synthesis of a hollow Cr2O3 electrocatalyst for enhanced nitrogen reduction toward ammonia synthesis 被引量:1
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作者 Lei Shi Yu Yin +7 位作者 Hong Wu Rajan Arjan Kalyan Hirani Xinyuan Xu jinqiang zhang Nasir Rafique Abdul Hannan Asif Shu zhang Hongqi Sun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第1期358-365,共8页
As a fascinating alternative to the energy-intensive Haber-Bosch process,the electrochemically-driven N_(2) reduction reaction(NRR)utilizing the N_(2) and H_(2)O for the production of NH3 has received enormous attenti... As a fascinating alternative to the energy-intensive Haber-Bosch process,the electrochemically-driven N_(2) reduction reaction(NRR)utilizing the N_(2) and H_(2)O for the production of NH3 has received enormous attention.The development and preparation of promising electrocatalysts are requisite to realize an efficient N_(2) conversion for NH3 production.In this research,we propose a template-assisted strategy to construct the hollow electrocatalyst with controllable morphology.As a paradigm,the hollow Cr_(2)O_(3) nanocatalyst with a uniform size(~170 nm),small cavity and ultrathin shell(~15 nm)is successfully fabricated with this strategy.This promising hollow structure is favourable to trap N_(2) into the cavity,provides abundant active sites to accelerate the three-phase interactions,and facilitates the reactant transfer across the shell.Attributed to these synergetic effects,the designed catalyst displays an outstanding behaviour in N_(2) fixation for NH3 production in ambient condition.In the neutral electrolyte of 0.1 mol·L^(-1) Na_(2)SO_(4),an impressive electrocatalytic performance with the NH3 generation rate of 2.72μg·h^(-1)·cm^(-2) and a high FE of 5.31%is acquired respectively at-0.85 V with the hollow Cr_(2)O_(3) catalyst.Inspired by this work,it is highly expected that this approach could be applied as a universal strategy and extended to fabricating other promising electrocatalysts for realizing highly efficient nitrogen reduction reaction(NRR). 展开更多
关键词 Hollow structure Electrocatalytic N_(2)fixation NH_(3)synthesis Template-assisted strategy Ambient condition
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A Comparison of Cloud Layers from Ground and Satellite Active Remote Sensing at the Southern Great Plains ARM Site 被引量:1
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作者 jinqiang zhang Xiang'ao XIA Hongbin CHEN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第3期347-359,共13页
Using the data collected over the Southern Great Plains ARM site from 2006 to 2010, the surface Active Remote Sensing of Cloud (ARSCL) and CloudSat-CALIPSO satellite (CC) retrievals of total cloud and six specifie... Using the data collected over the Southern Great Plains ARM site from 2006 to 2010, the surface Active Remote Sensing of Cloud (ARSCL) and CloudSat-CALIPSO satellite (CC) retrievals of total cloud and six specified cloud types [low, midlow (ML), high-mid-low (HML), mid, high-mid (HM) and high] were compared in terms of cloud fraction (CF), cloud-base height (CBH), cloud-top height (CTH) and cloud thickness (CT), on different temporal scales, to identify their respective advantages and limitations. Good agreement between the two methods was exhibited in the total CF. However, large discrepancies were found between the cloud distributions of the two methods at a high (240-m) vertical grid spacing. Compared to the satellites, ARSCL retrievals detected more boundary layer clouds, while they underestimated high clouds. In terms of the six specific cloud types, more low- and mid-level clouds but less HML- and high-level clouds were detected by ARSCL than by CC. In contrast, the ARSCL retrievals of ML- and HM-level clouds agreed more closely with the estimations from the CC product. Lower CBHs tended to be reported by the surface data for low-, ML- and HML-level clouds; however, higher CTHs were often recorded by the satellite product for HML-, HM- and high-level clouds. The mean CTs for low- and ML-level cloud were similar between the two products; however, the mean CTs for HML-, mid-, HM- and high-level clouds from ARSCL were smaller than those from CC. 展开更多
关键词 surface SATELLITE active remote sensing CLOUD
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Evaluation of multiple surface irradiance-based clear sky detection methods at Xianghe—A heavy polluted site on the North China Plain 被引量:1
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作者 Mengqi Liu jinqiang zhang Xiangao Xia 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第2期7-12,共6页
Surface irradiance measurements with high temporal resolution can be used to detect clear skies,which is a critical step for further study,such as aerosol and cloud radiative effects.Twenty-one clear-sky detection(CSD... Surface irradiance measurements with high temporal resolution can be used to detect clear skies,which is a critical step for further study,such as aerosol and cloud radiative effects.Twenty-one clear-sky detection(CSD)methods are assessed based on five years of 1-min surface irradiance data at Xianghe—a heavily polluted station on the North China Plain.Total-sky imager(TSI)discrimination results corrected by manual checks are used as the benchmark for the evaluation.The performance heavily relies on the criteria adopted by the CSD methods.Those with higher cloudy-sky detection accuracy rates produce lower clear-sky accuracy rates,and vice versa.A general tendency in common among all CSD methods is the detection accuracy deteriorates when aerosol loading increases.Nearly all criteria adopted in CSD methods are too strict to detect clear skies under polluted conditions,which is more severe if clear-sky irradiance is not properly estimated.The mean true positive rate(CSD method correctly detects clear sky)decreases from 45%for aerosol optical depth(AOD)≤0.2%to 6%for AOD>0.5.The results clearly indicate that CSD methods in a highly polluted region still need further improvements. 展开更多
关键词 Clear-sky detection methods Surface irradiance POLLUTION Total-sky imager
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Data-driven Estimation of Cloud Effects on Surface Irradiance at Xianghe,a Suburban Site on the North China Plain
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作者 Mengqi LIU jinqiang zhang +2 位作者 Hongrong SHI Disong FU Xiang'ao XIA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第12期2213-2223,共11页
Clouds are a dominant modulator of the energy budget.The cloud shortwave radiative effect at the surface(CRE)is closely related to the cloud macro-and micro-physical properties.Systematic observation of surface irradi... Clouds are a dominant modulator of the energy budget.The cloud shortwave radiative effect at the surface(CRE)is closely related to the cloud macro-and micro-physical properties.Systematic observation of surface irradiance and cloud properties are needed to narrow uncertainties in CRE.In this study,1-min irradiance and Total Sky Imager measurements from 2005 to 2009 at Xianghe in North China Plain are used to estimate cloud types,evaluate cloud fraction(CF),and quantify the sensitivities of surface irradiance with respect to changes in CF whether clouds obscure the sun or not.The annual mean CF is 0.50,further noting that CF exhibits a distinct seasonal variation,with a minimum in winter(0.37)and maximum in summer(0.68).Cumulus occurs more frequently in summer(32%),which is close to the sum of the occurrence of stratus and cirrus.The annual CRE is–54.4 W m^(–2),with seasonal values ranging from^(–2)9.5 W m^(–2)in winter and–78.2 W m^(–2)in summer.When clouds do not obscure the sun,CF is a dominant factor affecting diffuse irradiance,which in turn affects global irradiance.There is a positive linear relationship between CF and CRE under sun-unobscured conditions,the mean sensitivity of CRE for each CF 0.1 increase is about 1.2 W m^(–2)[79.5°<SZA(Solar Zenith Angle)<80.5°]to 7.0 W m^(–2)(29.5°<SZA<30.5°).When clouds obscure the sun,CF affects both direct and diffuse irradiance,resulting in a non-linear relationship between CF and CRE,and the slope decreases with increasing CF.It should be noted that,although only data at Xianghe is used in this study,our results are representative of neighboring areas,including most parts of the North China Plain. 展开更多
关键词 cloud radiative effect solar radiation cloud fraction cloud-radiation interaction
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Stratospheric balloon-based dropsonde technology:Development and preliminary assessment over the Tibetan Plateau
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作者 jinqiang zhang Hongbin Chen +5 位作者 Yunfei Du Wenzheng Shao Runping Zeng Keping Zhu Yi Liu Yuejian Xuan 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第3期30-35,共6页
To complement the atmospheric profile measurements under complex geographical environments and extreme weather conditions,a stratospheric balloon-based dropsonde technology,which is carried by a stratospheric balloon ... To complement the atmospheric profile measurements under complex geographical environments and extreme weather conditions,a stratospheric balloon-based dropsonde technology,which is carried by a stratospheric balloon platform from the Earth's surface to the upper troposphere and lower stratosphere(UTLS)to release the dropsonde for measurements,is independently developed and preliminarily assessed over the Tibetan Plateau(TP)in this study.The dropsonde system is mainly composed of the dropsonde chamber,dropsonde with a parachute,data receiving and communication antennas,dropsonde-releasing device,and GPS(Global Positioning System)modules.The dropsonde measurements can be sent in real time through satellite communication links and by radio signals to a data receiver at the ground control center for storage and processing.A total of eight dropsondes aboard the stratospheric balloon were successfully released during the TP campaign in 2020.A preliminary assessment was conducted based on a case comparison between the dropsonde and radiosonde measurements,which indicated that the dropsonde technology we developed can generally provide reasonable atmospheric profiles.However,further efforts are still required to improve the detection performance of the dropsonde sensors after long-term locating in the UTLS and to assess the accuracy and precision of the detection technology more carefully. 展开更多
关键词 Dropsonde technology Stratospheric balloon DEVELOPMENT Atmospheric profile Tibetan Plateau
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Impacts of the atmospheric apparent heat source over the Tibetan Plateau on summertime ozone vertical distributions over Lhasa
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作者 Wenjun Liang Zhen Yang +8 位作者 Jiali Luo Hongying Tian Zhixuan Bai Dan Li Qian Li jinqiang zhang Haoyue Wang Bian Ba Yang Yang 《Atmospheric and Oceanic Science Letters》 CSCD 2021年第3期66-71,共6页
The Tibetan Plateau(TP)is an area sensitive to climate change,where the ozone distribution affects the atmospheric environment of the TP and its surrounding regions.The relatively low total column ozone over the TP in... The Tibetan Plateau(TP)is an area sensitive to climate change,where the ozone distribution affects the atmospheric environment of the TP and its surrounding regions.The relatively low total column ozone over the TP in boreal summer and its spatiotemporal variations have received extensive attention.In this study,five-year balloon-borne measurements of ozone over Lhasa in boreal summer are used to investigate the influences of the apparent heat source(Q1)on the ozone vertical structure over the plateau.The mechanisms for the above processes are also explored.The results show that the tropospheric ozone mixing ratio over Lhasa decreases when the total atmospheric Q1 in the troposphere over the TP is relatively high.Strengthened ascending motions are accompanied by enhanced Q1 over the main TP region.Consequently,the tropospheric ozone mixing ratio over Lhasa decreases when Q1 is higher in summer,which is attributed to the upward transport of the ozone-poor surface air. 展开更多
关键词 OZONE Tibetan Plateau Atmospheric apparent heat source Ascending motion
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基于分块复合注意力的无人机小目标检测算法 被引量:1
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作者 于傲泽 魏维伟 +2 位作者 王平 张金强 柯文雄 《航空学报》 EI CAS CSCD 北大核心 2024年第14期42-52,共11页
针对常规目标检测算法在无人机小目标检测任务上特征提取难度大而导致检测精度低的问题,提出一种基于分块复合注意力的无人机小目标检测算法。首先,提出一种即插即用的分块复合注意力模块(PWCA),输入特征在空间维度切分成局部特征块,在... 针对常规目标检测算法在无人机小目标检测任务上特征提取难度大而导致检测精度低的问题,提出一种基于分块复合注意力的无人机小目标检测算法。首先,提出一种即插即用的分块复合注意力模块(PWCA),输入特征在空间维度切分成局部特征块,在局部特征块上提取通道注意力权重,加强通道信息在局部空间特征上的区分度,提高网络细粒度以适应小目标检测场景,然后融合输入特征与聚焦后的特征,并进一步挖掘空间注意力,关注网络中有效特征信息。其次,抛弃基线网络基于跨步卷积的下采样形式,结合PWCA提出自适应交错下采样模块(AID),根据重要程度自适应地分配下采样后的特征权重,减少下采样过程中小目标的信息损失。最后,对主干及特征融合网络进行轻量化设计,减少计算量并新增针对小目标的大尺寸特征图检测分支,优化了特征图的流动方向,丰富不同尺度特征图的语义信息,增强特征的表达能力,并保证实时性。针对性地采用Soft-NMS算法解决目标遮挡重叠时的漏检问题,提升检测效果。在公开数据集VisDrone2019上验证改进算法的有效性,与YOLOv5s目标检测算法相比,改进后算法最终的mAP0.5比YOLOv5s基线算法提升了11.81%,mAP0.5:0.95提升了10.91%,模型参数减少59%,网络在无人机小目标检测任务上能够较好地兼顾检测精度与推理速度,具有较大的实用意义。 展开更多
关键词 无人机 YOLOv5 小目标检测 注意力机制 下采样 特征融合
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The Earth Summit Mission-2022:Successful ozone soundings contribute to source identification in the north Mt.Qomolangma region 被引量:1
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作者 jinqiang zhang Chunxiang Ye +11 位作者 Yuejian Xuan Zhixuan Bai Weili Lin Dan Li Lingkun Ran Baofeng Jiao YaomingMa Weiqiang Ma Nan Yao Yunshu Zeng Daren Lv Tong Zhu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第2期412-421,共10页
As part of“The Earth Summit Mission-2022”during the second Tibetan Plateau Scientific Expedition and Research(STEP)in April and May 2022,we conducted the ozone sounding experiment(an ozonesonde mated to a radiosonde... As part of“The Earth Summit Mission-2022”during the second Tibetan Plateau Scientific Expedition and Research(STEP)in April and May 2022,we conducted the ozone sounding experiment(an ozonesonde mated to a radiosonde)at Mt.Qomolangma Base Camp(MQBC;86.85°E,28.14°N;5200 m),a location at an extremely high altitude.A total of ten sounding profiles were obtained between April 30 and May 06,2022,of which seven profiles were above35 km in altitude,with a maximum detection altitude up to 39.0 km.This study presents the temporal variation and vertical distributions of atmospheric temperature,humidity,and ozone during the MQBC campaign.The averaged ozone concentration was high(68.3 ppbv)at the surface and then increased smoothly until peaking(~110 ppbv)in the middle troposphere(approximately 10 km),and afterward,the ozone concentration increased rapidly from the upper troposphere to a maximum of~10 ppmv at~30 km.The enhanced ozone concentration in the middle troposphere was associated with the blocking high pressure,and transport from the southern flank of the Himalayas occurred during the campaign period.The average total ozone column was 291.9±21.4 DU for the seven profiles exceeding 35km in altitude.The ozonesonde measurements were also compared with the vertical ozone profiles retrieved from the space-borne ozone products from the Microwave Limb Sounder(MLS)onboard the Aura satellite and the Atmospheric Infrared Sounder(AIRS)onboard the Aqua satellite. 展开更多
关键词 Ozone soundings Mt.Qomolangma Vertical ozone structure Ozone source Satellite data
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