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Effects of thinning on the understory light environment of different stands and the photosynthetic performance and growth of the reforestation species Phoebe bournei

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Journal of Forestry Research 2024年第1期35卷 12-28页

作者： Shicheng Su nianqing Jin Xiaoli Wei College of Forestry Guizhou UniversityGuiyang 550025People’s Republic of China Institute for Forest Resources and Environment of Guizhou Guizhou UniversityGuiyang 550025People’s Republic of China

Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the *** this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei *** canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following *** improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light *** the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral *** photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light *** a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal *** a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of *** seedlings,and a reduction increased light absorption and use capacity and height:diameter *** growth advantage transformed from diameter to height,enabling seedlings to access more *** findings suggest that the regeneration of shade-tolerant species such as *** could be enhanced if a targeted approach to thinning based on stand type was adopted.

关键词： Thinning Understory light environment Phoebe bournei Photosynthetic performance Growth performance

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Copper ions influence the toxicity of β-amyloid(1-42) in a concen-tration-dependent manner in a Caenorhabditis elegans model of Alzheimer’s disease

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Science China(Life Sciences) 2011年第6期54卷 527-534页

作者： LUO YunFeng ZHANG Jie liu nianqing LUO Yuan ZHAO BaoLu State Key Laboratory of Brain & Cognitive Science Institute of BiophysicsChinese Academy of SciencesBeijing 100101China Graduate University of Chinese Academy of Sciences Beijing 100049China Department of Cell Biology and Neuroscience Rutgers UniversityPiscatawayNJ 08854USA Synchrotron Radiation Laboratory Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of Pharmaceutical Sciences University of MarylandBaltimoreMD 21201USA

β-amyloid (Aβ) and copper play important roles in the pathogenesis of Alzheimer’s disease (AD).However,the behavioral correlativity and molecular mechanisms of Aβ and copper toxicity have been investigated less *** the present study,we investigated the interaction and toxicity of Aβ1-42 and copper in the Aβ1-42 transgenic Caenorhabditis elegans worm model *** data show that the paralysis behavior of CL2006 worms significantly deteriorated after exposure to 10-3 mol L-1 copper ***,the paralysis behavior was dramatically attenuated with exposure to 10-4 mol L-1 copper *** exogenous copper treatment also partially changed the homeostatic balance of zinc,manganese,and *** data suggest that the accumulation of reactive oxygen species (ROS) was responsible for the paralysis induced by Aβ and copper in *** ROS generation induced by Aβ and copper appear to be through sod-1,prdx-2,skn-1,hsp-60 and hsp-16.2 genes.

关键词：淀粉样蛋白铜离子浓度依赖性老年痴呆症毒性模型线虫阿尔茨海默氏症

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Vertical ozone profiles deduced from measurements of SBUS on FY-3 satellite

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Chinese Science Bulletin 2010年第10期55卷 943-948页

作者： HUANG FuXiang liu nianqing ZHAO MingXian WANG ShuRong HUANG Yu National Satellite Meteorological Center Beijing 100081 China Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing 100081 China National Key Laboratory of Applied Optics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China

The FY-3 satellite is a second-generation Chinese polar-orbit meteorological *** Solar Backscatter Ultraviolet Sounder (SBUS),one of the main payloads on the FY-3 satellite,is the first Chinese ozone-monitoring instrument on a meteorological *** part of the in-orbit validation of FY-3,we carried out a retrieval trial using measurements from SBUS during the period of 17-30 July,2008,and compared those data with measurements and retrieved profiles from the National Oceanic and Atmospheric Administration (NOAA) satellite SBUV/*** results show that the precision of the measurements and retrieved profiles are quite *** averaged relative difference percentages of the ozone profiles retrieved from SBUS and those from SBUV/2 are within ±7%.

关键词：气象卫星臭氧监测测量数据垂直剖面紫外线探测器配置文件卫星探测器极地轨道

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Compositional change in human enamel irradiated with MIR free electron laser

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Chinese Science Bulletin 2001年第23期46卷 2016-2018页

作者： liu nianqing LI Yonggui ZHU Junbiao ZHANG Liwen WANG Mingkai WU Gang YANG Xueping Li Guangcheng Huang Yuying DONG Yanmei GAO Xuejun Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039China Stomatological College Peking UniversityBeijing 100081China 不详

The purpose of this study was to investigate compositional changes in human enamel irradiated with the free electron laser (FEL). The exposure on dental enamel at the wavelength of 9.64 μm was observed with the Beijing free electron laser. The distribution of elements in the irradiated or non-irradiated enamel was measured by scanning electron microscope (SEM) with energy-dispersive spectroscopy and synchrotron radiation X-ray fluorescence (SRXRF) in Beijing Synchrotron Radiation Facility (BSRF). The results showed that the P/Ca ratio in the ablation region of enamel at the maximum wavelength of infrared absorption was obviously smaller than that at the non-maximum wavelength. In the ablation region the ratios of P/Ca and Ca/Sr were smaller than those in the non-ablation region. The distributions of P, Ca and Sr in the ablation region were heterogeneous due to the element change caused by FEL irradiation.

关键词： human enamel Beijing free electron laser synchrotron radiation X-ray fluorescence ablation element distribution.

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一维管网与二维地表双向耦合的城市暴雨内涝模拟

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同济大学学报（自然科学版） 2024年第2期52卷 223-231页

作者：郑茂辉姚帅周念清刘俊兵同济大学上海防灾救灾研究所上海200092 同济大学城市安全风险监测预警应急管理部重点实验室上海200092 同济大学水利工程系上海200092

为快速、准确模拟城市暴雨内涝演化过程,提出一种排水管网与上覆地表动态水力交互方法,构建了一维管网模型(SWMM)与二维水动力(LISFLOOD-FP)双向耦合的模型,解决了一维管网和二维地表的双向流量交换和时间同步难题。以上海外高桥地区为... 详细信息

为快速、准确模拟城市暴雨内涝演化过程,提出一种排水管网与上覆地表动态水力交互方法,构建了一维管网模型(SWMM)与二维水动力(LISFLOOD-FP)双向耦合的模型,解决了一维管网和二维地表的双向流量交换和时间同步难题。以上海外高桥地区为例,采用两次短历时降雨过程对耦合模型进行校准和验证,比较分析了单向、双向耦合的淹没范围与水深变化。结果表明:双向耦合模拟精度较高,在研究区具有良好的适用性;对于占比80%以上的轻度(0.3 m)积水区,单向耦合模拟结果趋于严重,该比值分别增至1.88和2.1。所构建的双向耦合模型能够揭示城区内涝积水、扩散及消退的全过程,可用于城市暴雨内涝推演,为内涝治理和灾害防御提供科学依据。

关键词：城市暴雨内涝排水管网双向耦合流量交互时间同步

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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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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),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 ***: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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Revealing the role of electrode potential micro-environments in single Mn atoms for carbon dioxide and oxygen electrolysis

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Nano Research 2024年第9期17卷 7957-7966页

作者： Pengcheng liu anyi liu Kaili Wang Shuai Shi Mengmeng Jin Jingxiu liu Tao Qin Qian liu Xijun liu Jia He Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry and Chemical EngineeringInstitute of New-Energy Materials and Low-Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China School of Chemistry and Chemical Engineering and Environmental Engineering Weifang UniversityWeifang 261061China Department of Electrical Engineering and Automation Luoyang Institute of Science and TechnologyLuoyang 471023China Institute for Advanced Study Chengdu UniversityChengdu 610106China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured MaterialsSchool of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China

Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread *** we construct the well-defined Mn single-atom(MnSA)catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions(CO_(2)RR)and oxygen reduction reactions(ORR).MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90%at-0.9 V for CO_(2)RR and higher H_(2)O_(2)yield from 0.1 to 0.6 V with excellent ORR *** functional theory(DFT)calculations based on constant potential models were performed to study the mechanism of MnSA on CO_(2)*** thermodynamic energy barrier of CO_(2)RR is lowest at-0.9 V *** hydrogen electrode(RHE).Similar DFT calculations on the H_(2)O_(2)yield of ORR showed that the H_(2)O_(2)yield at 0.2 V was *** study provides a reasonable explanation for the role of electrode potential micro-environments.

关键词： electrode potential micro-environments Mn single-atom catalyst carbon dioxide reduction reaction oxygen reduction reaction constant potential models

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