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Characteristics of atmospheric nitrous oxide observed at Mt.Waliguan GAW global station in the inland Eurasia during eighteen years

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Science China Earth Sciences 2024年第1期67卷 92-104页

作者： Miao LIANG shuangxi FANG Lixin liu Yong ZHANG Jianqiong WANG Shuo liu Hongyang WANG Liangchun DENG Meteorological Observation Centre(MOC) China Meteorological Administration(CMA)Beijing 100081China College of Environment Zhejiang University of TechnologyHangzhou 310014China Mt.Waliguan Background Station China Meteorological Administration(CMA)Xining 810001China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Center for Environmental Progress Wuhan 430070China

This study presents atmospheric N_(2)O mole fractions measured from discrete air samples from 2001 to 2018 at Mt.Waliguan(WLG)station(36°17′N,100°54′E,3816 m asl)in China,which is a global background station of the World Meteorological Organization/Global Atmosphere Watch Programme(WMO/GAW)in central Eurasia.Observed N_(2)O characteristics of annual means,interannual variability,and seasonal cycles were investigated.Our results show that N_(2)O at WLG possess a distinct increasing trend and a statistically significant seasonal cycle,with an average growth rate of 0.9±0.01 ppb yr^(−1)(1σ)(1ppb=10^(−9)),which is close to the global mean.The detrended seasonal cycle shows a trough of−0.25±0.04(1σ)ppb in June and a peak of 0.13±0.07(1σ)ppb in September,with an amplitude of 0.38 ppb.The pattern is due to combined effects of variation in surface sources,vertical convection within the boundary layer and stratosphere to troposphere transportation(STE).The interannual variability in growth rate was partly driven by quasi-biennial oscillation(QBO)of tropical zonal wind through stratospheric transport into the troposphere.According to a cluster analysis of back trajectories and the corresponding average N_(2)O load,most air masses cover arid and semi-arid areas in inner Asia with low N_(2)O emissions,indicating that the atmospheric N_(2)O at the WLG represents the background N_(2)O level in central Eurasia.

关键词： Nitrous oxide(N_(2)O) Observation Long-term trend Seasonal variation Interannual variability

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Strategies and prospects for melatonin to alleviate abiotic stress in horticultural plants

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Horticultural Plant Journal 2024年第3期10卷 601-614页

作者： Xiaoyun Wang Meng Cao Hongxin Li Ying liu shuangxi Fan Na Zhang Yangdong Guo College of Horticulture China Agricultural UniversityBeijing100193China College of Plant Science and Technology Beijing University of AgricultureBeijing102206China Beijing Bei Nong Enterprise Management Co. Ltd.Beijing102206China Sanya Institute of China Agricultural University SanyaHainan572000China

Melatonin is a conserved pleiotropic molecule in animals and plants.Melatonin is involved in many development processes and stress responses;thus,exploring its function in plants,particularly in horticultural plants,has become a rapidly developing field.Many studies have revealed that phytomelatonin acts as a plant biostimulant and increase its tolerance to various abiotic stressors,including extreme temperature,drought,osmotic disturbance,heavy metals,and ultraviolet(UV).Melatonin appears to have roles in the scavenging of reactive oxygen species(ROS)and other free radicals,affecting the primary and secondary metabolism of plants,regulating the transcripts of stress-related enzymes and transcription factors,and crosstalk with other hormones under different environmental conditions.This pleiotropy makes phytomelatonin an attractive regulator to improve resistance to abiotic stress in plants.The recent discovery of the potential phytomelatonin receptor CAND2/PMTR1 and the proposition of putative models related to the phytomelatonin signaling pathways makes phytomelatonin a new plant hormone.Based on relevant studies from our laboratory,this review summarizes the phytomelatonin biosynthetic and metabolic pathways in plants and the latest research progress on phytomelatonin in abiotic stress of horticultural plants.This study will provide a reference for elucidating the regulatory mechanism of phytomelatonin affecting the resistance to abiotic stress in plants.

关键词： Abiotic stress Biostimulant Horticultural plants Phytomelatonin

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Compliant Iontronic Triboelectric Gels with Phase-Locked Structure Enabled by Competitive Hydrogen Bonding

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Nano-Micro Letters 2024年第9期16卷 180-194页

作者： Guoli Du Yuzheng Shao Bin Luo Tao liu Jiamin Zhao Ying Qin Jinlong Wang Song Zhang Mingchao Chi Cong Gao Yanhua liu Chenchen Cai Shuangfei Wang shuangxi Nie School of Light Industry and Food Engineering Guangxi UniversityNanning 530004People’s Republic of China

Rapid advancements in flexible electronics technology propel soft tactile sensing devices toward high-level biointegration,even attaining tactile perception capabilities surpassing human skin.However,the inherent mechanical mismatch resulting from deficient biomimetic mechanical properties of sensing materials poses a challenge to the application of wearable tactile sensing devices in human-machine interaction.Inspired by the innate biphasic structure of human subcutaneous tissue,this study discloses a skin-compliant wearable iontronic triboelectric gel via phase separation induced by competitive hydrogen bonding.Solvent-nonsolvent interactions are used to construct competitive hydrogen bonding systems to trigger phase separation,and the resulting soft-hard alternating phase-locked structure confers the iontronic triboelectric gel with Young’s modulus(6.8-281.9 kPa)and high tensile properties(880%)compatible with human skin.The abundance of reactive hydroxyl groups gives the gel excellent tribopositive and self-adhesive properties(peel strength>70 N m^(−1)).The self-powered tactile sensing skin based on this gel maintains favorable interface and mechanical stability with the working object,which greatly ensures the high fidelity and reliability of soft tactile sensing signals.This strategy,enabling skin-compliant design and broad dynamic tunability of the mechanical properties of sensing materials,presents a universal platform for broad applications from soft robots to wearable electronics.

关键词： Triboelectric nanogenerator Cellulose Triboelectric gel Self-powered sensor Energy harvesting

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Current status and prospects of terminal guidance laws for intercepting hypersonic vehicles in near space:a review

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第5期24卷 387-403页

作者： shuangxi liu Binbin YAN Wei HUANG Xu ZHANG Jie YAN Unmanned System Research Institute Northwestern Polytechnical UniversityXi'an 710072China School of Astronautics Northwestern Polytechnical UniversityXi'an 710072China Science and Technology on Scramjet Laboratory School of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China

The unique performance advantages of hypersonic vehicles represent a critical challenge for existing defense systems.To facilitate defensive operations against hypersonic vehicles in near space,this paper systematically discusses both the advantages of these vehicles and the difficulties in intercepting them.Focusing on the state-of-the-art terminal guidance laws for intercepting hypersonic vehicles in near space,we examine research progress in the area of single-and multi-interceptor cooperative guidance laws and summarize their advantages and disadvantages.We also highlight future research directions for developing an effective terminal guidance law for multi-interceptor cooperative interception of hypersonic vehicles,based on four aspects:the information domain,space domain,physical domain,and effect-cost ratio.The findings provide a reference for further research into near-space interceptor terminal guidance technologies.

关键词： Hypersonic vehicles Guidance law Cooperative guidance Near space

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ZnFe_(2)O_(4)/BiVO_(4)Z-scheme heterojunction for efficient visible-light photocatalytic degradation of ciprofloxacin

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Frontiers of Chemical Science and Engineering 2023年第11期17卷 1728-1740页

作者： Beibei Wang Kejiang Qian Weiping Yang Wenjing An Lan-Lan Lou shuangxi liu Kai Yu MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Technology for Complex Transmedia PollutionCollege of Environmental Science and EngineeringNankai UniversityTianjin 300350China Institute of New Catalytic Materials Science School of Materials Science and EngineeringNational Institute of Advanced MaterialsNankai UniversityTianjin 300350Chin

A novel Z-scheme ZnFe_(2)O_(4)/BiVO_(4)heterojunction photocatalyst was successfully synthesized using a convenient solvothermal method and applied in the visible light photocatalytic degradation of ciprofloxacin,which is a typical antibiotic contaminant in wastewater.The heterostructure of as-synthesized catalysts was confirmed using X-ray diffraction,scanning electron microscopy,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations.Compared with the singlephase counterparts,ZnFe_(2)O_(4)/BiVO_(4)demonstrated considerably enhanced photogenerated charge separation efficiencies because of the Z-scheme transfer mechanism of electrons between the composite photocatalysts.Consequently,the 30%ZnFe_(2)O_(4)/BiVO_(4)catalyst afforded a degradation rate of up to 97%of 20 mg/L ciprofloxacin under 30 min of visible light irradiation with a total organic carbon removal rate of 50%,which is an excellent activity compared with ever reported BiVO_(4)-based catalysts.In addition,the liquid chromatography-mass spectrometry and quantitative structure-activity relationships model analyses demonstrated that the toxicity of the intermediates was lower than that of the parent ciprofloxacin.Moreover,the as-synthesized ZnFe_(2)O_(4)/BiVO_(4)heterojunctions were quite stable and could be reused at least four times.This study thus provides a promising Z-scheme heterojunction photocatalyst for the efficient removal and detoxication of antibiotic pollutants from wastewater.

关键词： ZnFe_(2)O_(4)/BiVO_(4) Z-scheme heterojunction photocatalytic degradation ciprofloxacin

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Application of activated carbon derived from scrap tires for adsorption of Rhodamine B

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Journal of Environmental Sciences 2010年第8期22卷 1273-1280页

作者： Li Li shuangxi liu Tan Zhu Institute of New Catalytic Materials Science College of Chemistry Nankai University Tianjin 300071 China College of Environmental Science and Engineering Nankai University Tianjin 300071 China

Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char （APTC） for Rhodamine B （RhB）. Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little effect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.

关键词： activated pyrolytic tire char Rhodamine B adsorption isotherm thermodynamics

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Effectiveness and safety of acupuncture in treatment of pregnancyrelated symptoms:a systematic review and Meta-analysis

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Journal of Traditional Chinese Medicine 2024年第1期44卷 16-26页

作者： liu Tingting liu Tongou liu Mingfu School of Traditional Chinese Medicine Clinical Medicine Hubei University of Traditional Chinese MedicineWuhan 430000China First Clinical College of Hubei University of Traditional Chinese Medicine Wuhan 430000China Department of Acupuncture and Tuina Affiliated Hospital of Hubei University of Traditional Chinese MedicineHubei Provincial Hospital of Traditional Chinese MedicineWuhan 430000China

OBJECTIVE:To systematically evaluate the efficacy and safety of acupuncture(AM)in the treatment of pregnancyrelated symptoms such as acute vomiting during pregnancy.METHODS:We comprehensively searched the available literature up to November 2021,including Pub Med,Embase,Cochrane Library,Chinese Biomedical Literature Database,and China National Knowledge Infrastructure Database,for randomized controlled trials(RCTs)on AM for the treatment of severe vomiting,insomnia,pharyngeal and pelvic pain,mood abnormalities,and dyspepsia during pregnancy.RESULTS:Sixteen RCTs with a cumulative sample size of 1178 cases were included.Of these,964 patients were included in the Meta-analysis.The Meta-analysis results showed that AM was more efficient than Western medicine in treating discomfort during pregnancy[odds ratio(OR)=1.19,95%confidence interval(CI)(1.11,1.28),P<0.01].AM was better than the control group in improving the visual analog scale scores[standard mean difference(SMD)=0.62,95%CI(0.53,0.71),P<0.01].AM was superior to the control group in improving Numerical Rating Scale(NRS)symptom scores[OR=7.31,95%CI(3.36,15.94),P<0.01].There was no significant difference in adverse effects between the AM and sham-AM groups and the analgesic drug group[OR=0.70,95%CI(0.39,1.28),P=0.25],but the treatment and control groups had mild adverse effects with a low incidence.CONCLUSIONS:AM is more effective than other treatments or pharmacotherapy alone in the treatment of pregnancy-related symptoms,and is relatively safe.However,the quality of the included trials was rather poor,and high-quality studies are required to confirm our findings.

关键词： acupuncture pregnancy nausea vomiting sleep initiation and maintenance disorders low back pain pelvic pain mood abnormalities Meta-analysis systematic review

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Removal of Cr(Ⅵ)by glutaraldehyde-crosslinked chitosan encapsulating microscale zero-valent iron:Synthesis,mechanism,and longevity

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Journal of Environmental Sciences 2024年第8期142卷 115-128页

作者： Yijun Duan Fang liu Xiang liu Miao Li School of Environment Tsinghua UniversityBeijing 100084China Transportation Institute of Inner Mongolia University Hohhot 010070China

Microscale zero-valent iron(mZVI)has shown great potential for groundwater Cr(Ⅵ)remediation.However,low Cr(Ⅵ)removal capacity caused by passivation restricted the wide use of mZVI.We prepared mZVI/GCS by encapsulating mZVI in a porous glutaraldehydecrosslinked chitosan matrix,and the formation of the passivation layer was alleviated by reducing the contact between zero-valent iron particles.The average pore diameter of mZVI/GCS was 8.775 nm,which confirmed the mesoporous characteristic of this material.Results of batch experiments demonstrated that mZVI/GCS exhibited high Cr(Ⅵ)removal efficiency in a wide range of pH(2-10)and temperature(5-35℃).Common groundwater coexisting ions slightly affected m ZVI/GCS.The material showed great reusability,and the average Cr(Ⅵ)removal efficiency was 90.41%during eight cycles.In this study,we also conducted kinetics and isotherms analysis.Pseudo-second-order model was the most matched kinetics model.The Cr(Ⅵ)adsorption process was fitted by both Langmuir and Freundlich isotherms models,and the maximum Langmuir adsorption capacity of m ZVI/GCS reached243.63 mg/g,which is higher than the adsorption capacities of materials reported in most of the previous studies.Notably,the column capacity for Cr(Ⅵ)removal of a mZVI/GCS-packed column was 6.4 times higher than that of a mZVI-packed column in a 50-day experiment.Therefore,mZVI/GCS with a porous structure effectively relieved passivation problems of mZVI and showed practical application prospects as groundwater Cr(Ⅵ)remediation material with practical application prospects.

关键词： Chitosan Glutaraldehyde mZVI Cr(Ⅵ) Groundwater

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Spontaneous migration induced Co nanokarstcave encapsulated in N-doped carbon hybrids for efficient oxygen electrocatalyst

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Nano Research 2021年第12期14卷 4569-4576页

作者： Xuemin Wang Ming liu Hang Zhang Sihao Yan Cui Zhang shuangxi liu School of Materials Science and Engineering Institute of New Catalytic Materials ScienceNankai UniversityTianjin300350China National Institute for Advanced Materials Nankai UniversityTianjin300350China Key Laboratory of Advanced Energy Materials Chemistry Ministry of EducationNankai UniversityTianjin300071China Collaborative Innovation Center of Chemical Science and Engineering Tianjin300072China

Despite the extensive application of porous nanostructures as oxygen electrocatalysts, it is challenging to synthesize single-metal state materials with porous structures, especially the ultrasmall ones due to the uniform diffusion of the same metal. Herein, we pioneer demonstrate a new size effect-based controllable synthesis strategy for the homogeneous Co nanokarstcaves assisted by Co-CN hybrids (CCHs). The preferential migration of cobalt atoms on the surface of small size zeolitic imidazolate framework (ZIF) with high surface energy during pyrolysis is the key factor for the formation of nanokarstcave structure. Furthermore, graphene can act as a diffusion barrier to prevent the agglomeration of nanoparticles in the synthesis process, which also plays an important role in the formation of porous nanostructures. In alkali media, CCHs achieve overpotential of 287 mV (@10 mA·cm^(−2)) for oxygen evolution reaction (OER) and a half wave potential of 0.86 V (vs. RHE) for oxygen reduction reaction (ORR).

关键词： size effect spontaneous migration Co nanokarstcave oxygen electrocatalyst multicomponent synergy

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Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 275-286页

作者： Haoyu liu Chongru liu North China Electric Power University Beijing 102206China

Frequency regulation of voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC)system with offshore wind farms enhances the frequency stability by compensating the power for a disturbed AC system.However,it is difficult to reasonably allocate frequency-regulation resources due to a lack of coordination mechanisms between wind farms and the MTDC system.Moreover,it is difficult for the frequency control of the wind farms to manage changes in wind speed;and the risk of wind-turbine stalls is high.Thus,based on the kinetic energy of wind turbines and the power margin of the converters,the frequency-regulation capability of wind turbines is evaluated,and a dynamic frequency-support scheme considering the real-time frequency-support capability of the wind turbines and system frequency evolution is proposed to improve the frequency-support performance.A power adaptation technique at variable wind speeds is developed;the active power in the frequency-support stage and restoration stage is switched according to the wind speed.A hierarchical zoning frequency-regulation scheme is designed to use the frequency-regulation resources of different links in the MTDC system with wind farms.The simulation results show that the novel frequency-regulation strategy maintains frequency stability with wind-speed changes and avoids multiple frequency dips.

关键词： Wind generation voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC) frequency regulation cooperative control adaptive control variable wind speed

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