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A native herbaceous community exerts a strong allelopathic effect on the woody range-expander Betula fruticosa

Journal of Plant Ecology 2024年第4期17卷 131-140页

作者： Lichao Wang Ayub M.o.oduor Yanjie liu State Key Laboratory of Black Soils Conservation and Utilization Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China University of Chinese Academy of Sciences Beijing 100049China Department of Applied Biology Technical University of KenyaNairobiKenya

Biological invasions by alien and range-expanding native plant species can suppress native plants through ***,the homeland security hypothesis suggests that some native plants can resist invasion by producing allelopathic compounds that inhibit the growth of invasive *** research has focused on allelopathic interactions between individual native and invasive plant species,with less emphasis on how allelopathy helps entire native communities resist ***,limited knowledge exists about allelopathic interactions between range-expanding native species and recipient native communities,and their influence on invasion *** bridge this knowledge gap,we conducted two greenhouse competition experiments to test reciprocal allelopathic effects between a native woody range-expanding species,Betula fruticosa,and a community of four native herbaceous species(Sanguisorba officinalis,Gentiana manshurica,Sium suave and Deyeuxia angustifolia)in *** assessed whether *** and the native community differed in their competitive effects and responses,and whether these were influenced by activated carbon,which neutralizes allelochemicals in the *** carbon reduced the suppressive effects of the native community on the above-ground biomass of ***,which indicates that the native community exerted a strong allelopathic effect on *** contrast,activated carbon only marginally enhanced the suppressive effects of *** on the native community,which indicates that allelopathy is not the primary mechanism by which *** exerts its ***,these findings support the homeland security hypothesis and suggest that biotic resistance from the native herbaceous community may limit the invasion success of the woody range-expander ***.

关键词： allelochemicals competition encroachment global change non-native shrub

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3D printing of poly(ethyleneimine)-functionalized Mg-Al mixed metal oxide monoliths for direct air capture of Co_(2)

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Journal of Energy Chemistry 2024年第9期96卷 491-500页

作者： Qingyang Shao Zhuozhen Gan Bingyao Ge Xuyi liu Chunping Chen Dermot o’Hare Xuancan Zhu Research Center of Solar Power&Refrigeration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Chemistry Research Laboratory Department of ChemistryUniversity of OxfordOxford OX13TAUK

Direct air capture(DAC)of Co_(2)plays an indispensable role in achieving carbon-neutral goals as one of the key negative emission *** large air flows are required to capture the ultradilute Co_(2)from the air,lab-synthesized adsorbents in powder form may cause unacceptable gas pressure drops and poor heat and mass transfer efficiencies.A structured adsorbent is essential for the implementation of gas-solid contactors for cost-and energy-efficient DAC *** this study,efficient adsorbent poly(ethyleneimine)(PEI)-functionalized Mg-Al-Co_(3)layered double hydroxide(LDH)-derived mixed metal oxides(MMos)are three-dimensional(3D)printed into monoliths for the first time with more than 90%adsorbent *** printing process has been optimized by initially printing the LDH powder into monoliths followed by calcination into MMo *** structure exhibits a 32.7%higher specific surface area and a 46.1%higher pore volume,as compared to the direct printing of the MMo powder into a *** impregnation of PEI,the monolith demonstrates a large adsorption capacity(1.82 mmol/g)and fast kinetics(0.7 mmol/g/h)using a Co_(2)feed gas at 400 ppm at 25℃,one of the highest values among the shaped DAC *** of the amino-polymers during the post-printing process affects the diffusion of Co_(2),resulting in slower adsorption kinetics of pre-impregnation monoliths compared to post-impregnation *** optimal PEI/MeoH ratio for the post-impregnation solution prevents pores clogging that would affect both adsorption capacity and kinetics.

关键词： 3D printing Mixed metal oxides Amine functionalization Structured adsorbent Direct air capture

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Assimilation of GoES-R Geostationary Lightning Mapper Flash Extent Density Data in GSI 3DVar, EnKF, and Hybrid En3DVar for the Analysis and Short-Term Forecast of a Supercell Storm Case

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Advances in Atmospheric Sciences 2024年第2期41卷 263-277页

作者： Rong KoNG Ming XUE Edward R.MANSELL Chengsi liu Alexandre o.FIERRo Center for Analysis and Prediction of Storms Norman Oklahoma 73072U.S.A University of oklahoma Norman Oklahoma 73072U.S.A NoAA/National Severe Storms Laboratory NormanOklahoma 73072U.S A.4Zentralanstalt für Meteorologie und Geodynamik Department of Forecasting Models-ZAMGVienna 1190Austria

Capabilities to assimilate Geostationary operational Environmental Satellite “R-series ”(GoES-R) Geostationary Lightning Mapper(GLM) flash extent density(FED) data within the operational Gridpoint Statistical Interpolation ensemble Kalman filter(GSI-EnKF) framework were previously developed and tested with a mesoscale convective system(MCS) case. In this study, such capabilities are further developed to assimilate GoES GLM FED data within the GSI ensemble-variational(EnVar) hybrid data assimilation(DA) framework. The results of assimilating the GLM FED data using 3DVar, and pure En3DVar(PEn3DVar, using 100% ensemble covariance and no static covariance) are compared with those of EnKF/DfEnKF for a supercell storm case. The focus of this study is to validate the correctness and evaluate the performance of the new implementation rather than comparing the performance of FED DA among different DA schemes. only the results of 3DVar and pEn3DVar are examined and compared with EnKF/DfEnKF. Assimilation of a single FED observation shows that the magnitude and horizontal extent of the analysis increments from PEn3DVar are generally larger than from EnKF, which is mainly caused by using different localization strategies in EnFK/DfEnKF and PEn3DVar as well as the integration limits of the graupel mass in the observation operator. overall, the forecast performance of PEn3DVar is comparable to EnKF/DfEnKF, suggesting correct implementation.

关键词： GoES-R lightning data assimilation EnKF EnVar

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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 ***,it is difficult to reasonably allocate frequency-regulation resources due to a lack of coordination mechanisms between wind farms and the MTDC ***,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 ***,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 *** 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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Interface engineering of Co_(9)S_(8)/SnS heterostructure as a high-performance anode for lithium/sodium-ion batteries

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Rare Metals 2024年第2期43卷 612-623页

作者： Jia Luo Shi-Li Xiang Dan-Yang Han An liu João Cunha Gang-Yong Li Zhao-Hui Hou Hong Yin School of Chemistry and Chemical Engineering Key Laboratory of Hunan Province for Advanced Carbon-based Functional MaterialsHunan Institute of Science and TechnologyYueyang414006China Hubei Jiufengshan Laboratory Wuhan430206China International Iberian Nanotechnology Laboratory(INL) Av.Mestre Jose Veiga4715-330BragaPortugal

Transition metal sulfide(TMS)anodes exhibit the characteristics of phase stability and high capacity for lithium/sodium-ion batteries(LIBs/SIBs).However,the TMS anodes often suffer from poor electronic conductivity,low ionic diffusion and large volume expansion during Li/Na-ion intercalation significantly impairing the Li/Na-storage ***,a long chain heterostructure composed of the Co_(9)S_(8) and SnS are first reported,which can generate rich phase interfaces,and small crystal *** unique structure can facilitate the properties of reactivity,conductivity and ionic *** addition,the heterostructure surface is modified by the N-doped carbon(N-DC@(CoSn)S),successfully improving the structural *** synergistic effects of Co_(9)S_(8)/SnS heterostructure and coated carbon layer effectively increase the capacity and cycling *** N-DC@(CoSn)S anode delivers enhanced high specific capacities of 820.6 mAh·g^(−1) at 1.0 A·g^(–1) after 500 cycles for LIBs and 339.2 mAh·g^(–1)at 0.5 A·g^(–1) after 1000 cycles for SIBs,*** work is expected to provide a material design idea for preparing LIBs/SIBs with high capacity and long cycling life.

关键词： Interface engineering Long chain heterostructure High capacity Cycling stability Li Na-ion batteries

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Progress of Lyman-alpha-based beam emission spectroscopy(Ly BES)diagnostic on the HL-2A tokamak

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Plasma Science and Technology 2024年第3期26卷 118-125页

作者：周艺轩余羿许敏柯锐聂林徐皓赵光义刘灏袁子豪肖晨雨李继全肖池阶 the HL-2A Team Southwestern Institute of Physics Chengdu 610041People's Republic of China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082People's Republic of China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China

An edge Lyman-alpha-based beam emission spectroscopy(LyBES)diagnostic,using a heating NBI(neutral beam injection)system,is currently under development on the HL-2A *** 20-channel edge LyBES,which is intended to measure the density fluctuation in plasma edge(from R=1960 mm to R=2026 mm)with an improved spatial resolution of 3.3 mm,is a complement to the existing conventional beam emission spectroscopy(BES)*** this article,we introduce the progress of LyBES diagnostic,including the collection optics,the monochromator,and the detector *** reflectance of the collection mirrors is measured to be~82%at 122 nm,and the aberration geometrical radius of the collection optics is tested to be~150μm in the aimed *** linear dispersion of the LyBES monochromator is designed to be~0.09 nm mm^(-1).The bandwidth of the detector system with the 5×10^(7)V A^(-1)preamplifier gain is measured to be~280 kHz,and the peak-to-peak noise of the detector system is tested to be~16 *** finalized design,components development and testing of the LyBES diagnostic have been completed at present,and an overall performance of the LyBES diagnostic is to be confirmed in the next HL-2A campaign.

关键词： density fluctuation Ly BES BES vacuum ultraviolet

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A Novel Design of a Pre-separation Panel Structure to Protect Against the Impact of an Explosion in an Aircraft Plenum Chamber

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Acta Mechanica Solida Sinica 2024年第1期37卷 166-180页

作者： Zongxing liu Xiang Yang Jun liu School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China CoMAC Shanghai Aircraft Design and Research Institute Shanghai 201210China

To reduce the damage of the pressurizing panel structure of a fuselage caused by an explosion at the“least risk bomb location”in an aircraft structure,a new pre-separation panel structure was designed to resist blast ***,the dynamic strain response and morphology of impact damage of the new pre-separation panel were measured in an impact damage ***,the commercial software LS-DYNA was used to calculate the propagation of the blast shock wave,and the results were compared with empirical equations to verify the rationality of the numerical calculation ***,the fluid–structure coupling method was used to calculate the damage process of the pre-separation panel structure under the impact of an explosion wave and an impact *** calculated results were in good agreement with the test results,which showed the rationality of the calculation method and the *** residual strength of the damaged pre-separation panel was significantly higher than that of the original damaged *** results show that the new pre-separation panel structure is reasonable and has certain significance for guiding the design of plenum chambers with strong resistance to implosion for aircraft fuselages.

关键词： Pre-separation panel structure Explosive response Residual strength Aircraft plenum chamber Least risk bomb location

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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 ***: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 ***:Sixteen RCTs with a cumulative sample size of 1178 cases were *** these,964 patients were included in 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),Pontrol group in improving the visual analog scale scores[standard mean difference(SMD)=0.62,95%CI(0.53,0.71),Por to the control group in improving Numerical Rating Scale(NRS)symptom scores[oR=7.31,95%CI(3.36,15.94),Po 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 ***:AM is more effective than other treatments or pharmacotherapy alone in the treatment of pregnancy-related symptoms,and is relatively ***,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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Stochastic Unit Commitment with High-Penetration offshore Wind Power Generation in Typhoon Scenarios

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 535-546页

作者： Yanqi liu Dundun liu Hongcai Zhang State Key Laboratory of Internet of Things for Smart City and Department of Electrical and Computer Engineering University of MacaoMacao 999078China University of Macao Zhuhai UM Science and Technology Research Institute ZhuhaiChina

To tackle the energy crisis and climate change,wind farms are being heavily invested in across the *** China's coastal areas,there are abundant wind resources and numerous offshore wind farms are being *** secure operation of these wind farms may suffer from typhoons,and researchers have studied power system operation and resilience enhancement in typhoon ***,the intricate movement of a typhoon makes it challenging to evaluate its spatial-temporal *** published papers only consider predefined typhoon trajectories neglecting *** address this challenge,this study proposes a stochastic unit commitment model that incorporates high-penetration offshore wind power generation in typhoon *** adopts a data-driven method to describe the uncertainties of typhoon trajectories and considers the realistic anti-typhoon mode in offshore wind farms.A two-stage stochastic unit commitment model is designed to enhance power system resilience in typhoon *** formulate the model into a mixed-integer linear programming problem and then solve it based on the computationally-efficient progressive hedging algorithm(PHA).Finally,numerical experiments validate the effectiveness of the proposed method.

关键词： Unit commitment two-stage stochastic programming offshore wind farm typhoon

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Devolatilization of high viscous fluids with high gravity technology

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Chinese Journal of Chemical Engineering 2024年第7期71卷 249-257页

作者： Jibing Qi Youzhi liu Yandong liu Taiyuan University Taiyuan 030032China Shanxi Province Key Laboratory of Higee-oriented Chemical Engineering North University of ChinaTaiyuan 030051China

Volatile organic compounds(VoCs)are generally toxic and harmful substances that can cause health and environmental *** removal of VoCs from polymers has become a key *** effective devolatilization to remove VoCs from high viscous fluids such as polymer is necessary and is of great *** this study,the devolatilization effect of a rotating packed bed(RPB)was studied by using polydimethylsiloxane as the viscous fluid and acetone as the *** devolatilization rate and liquid phase volume(KLa)have been *** results indicated that the optimum conditions were the high-gravity factor of 60,liquid flow rate of 10 L·h^(-1),and vacuum degree of 0.077 *** dimensionless correlation of KLa was established,and the deviations between predicted and experimental values were less than±28%.The high-gravity technology will result in lower mass transfer resistance in the devolatilization process,enhance the mass transfer process of acetone,and improve the removal effect of *** work provides a promising path for the removal of volatiles from polymers in combination with high-gravity *** can provide the basis for the application of RPB in viscous fluids.

关键词： High-gravity technology Devolatilization rate High viscous fluid Volatile organic compounds(VoCs)

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