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Hydraulic properties and drought response of a tropical bamboo (Cephalostachyum pergracile)

Plant Diversity 2024年第3期46卷 406-415页

作者： Wanwalee Kongjarat Lu Han Amy Ny Aina Aritsara shu-Bin zhang Gao-Juan Zhao Yong-Jiang zhang Phisamai Maenpuen Ying-mei Li Yi-Ke Zou Ming-Yi Li Xue-Nan Li Lian-Bin Tao Ya-Jun Chen CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesYunnan 666303China University of the Chinese Academy of Sciences Beijing 100049China T-STAR Core Team Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesYunnan 666303China School of Biology and Ecology University of MaineOronoMEUSA Climate Change Institute University of MaineOronoME 04469USA School of Biological and Chemical Science Pu’er UniversityXueyuan RoadYunnan 665000China Institute of Ecology and Geobotany School of Ecology and Environmental SciencesYunnan UniversityKunmingYunnan 650091China School of Ecology and Environment Southwest Forestry UniversityKunmingYunnan 650224China Yuanjiang Savanna Ecosystem Research Station Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesYuanjiangYunnan 653300China

Bamboo plants are an essential component of tropical ecosystems,yet their vulnerability to climate extremes,such as drought,is poorly understood due to limited knowledge of their hydraulic *** pergracile,a commonly used tropical bamboo species,exhibited a substantially higher mortality rate than other co-occurring bamboos during a severe drought event in 2019,but the underlying mechanisms remain *** study investigated the leaf and stem hydraulic traits related to drought responses,including leaf-stem embolism resistance(P50leaf;P50stem) estimated using optical and X-ray microtomography methods,leaf pressure-volume and water-releasing ***,we investigated the seasonal water potentials,native embolism level(PLC) and xylem water source using stable *** found that *** exhibited strong resistance to embolism,showing low P50leaf,P50stem,and turgor loss point,despite its rapid leaf water ***,its leaves displayed greater resistance to embolism than its stem,suggesting a lack of effective hydraulic vulnerability segmentation(HVS) to protect the stem from excessive xylem *** the dry season,approximately 49% of the water was absorbed from the upper 20-cm-deep soil ***,significant diurnal variation in leaf water potentials and an increase in midday PLC from 5.87±2.33% in the wet season to 12.87±4.09%in the dry season were *** summary,this study demonstrated that the rapid leaf water loss,high reliance on surface water,and a lack of effective HVS in *** accelerated water depletion and increased xylem embolism even in the typical dry season,which may explain its high mortality rate during extreme drought events in 2019.

关键词： Climate change Drought Hydraulic safety Hydraulic vulnerability segmentation Stable isotope Tree mortality

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Simulation of fire emergency evacuation in a large-passenger-flow subway station based on the on-site measured data of Shenzhen Metro

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Transportation Safety and Environment 2024年第1期6卷 47-55页

作者： Hua Chen Chenyang zhang Jieyu zhang Ya shu Xinjian Qi Chaozhe Jiang Sichuan FAST Fire Safety Assessment Co. LTD.Chengdu 610036SichuanChina School of Transportation and Logistics Southwest Jiaotong UniversityChengdu 611756SichuanChina Sichuan Fire Research Institute of MEM Chengdu 610036SichuanChina Shenzhen Metro Group Co. LTD.Shenzhen 518026GuangdongChina

Because of its large capacity,high efficiency and energy savings,the subway has gradually become the primary mode of transportation for citizens.A high density of passengers exists within a large-passenger-flow subway station,and the number of casualties and injuries during a fire emergency is *** this paper,Pathfinder software and on-site measured data of Pingzhou station in Shenzhen(China)were utilized to simulate a fire emergency evacuation in a large-passenger-flow subway *** Required Safe Egress Time(RSET),number of passengers and flow rates of stairs and escalators were analysed for three fire evacuation scenarios:train fire,platform fire and hall *** evacuation time of the train fire,which was 1173 s,was the longest,and 3621 occupants needed to evacuate when the train was fully *** could not complete the evacuation within 6 mins in all three fire evacuation scenarios,which does not meet the current standard requirements and *** changing the number of passengers and the number of stairs for evacuation,the flow rate capacity and evacuation time were explored,which have reference values for safety management and emergency evacuation plan optimization during peak hours of subway operation.

关键词： fire emergency evacuation large-passenger-flow subway station on-site measured data Pathfinder

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Both host and diet shape bacterial communities of predatory mites

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Insect Science 2024年第2期31卷 551-561页

作者： Hong Yan Endong Wang Guo-shu Wei Bo zhang Xuenong Xu Institute of Plant Protection Chinese Academy of Agricultural SciencesBejingChina College of Plant Protection Hebei Agricultural UniversityBaodingHebei ProvinceChina Key Laboratory of Natural Enemies Insects Ministry of Agriculture and Rural AffairsBeijingChina

Microbial communities,derived from food,ambient,and inner,can affect host ecological adaption and *** with most phytophagous arthropods,predators may have more opportunities to develop specific microbiota depending on the level of prey *** explore how diet sources affect host microbial communities and vary across predator species,we considered 3 types of predators from Phytoseiidae(Acari:Mesostigmata):polyphagous(Amblyseius orientalis Ehara,Neoseiulus barkeri Hughes,and Amblyseius swirski Athias-Henrio),oligophagous(Neoseiulus californicus McGregor),and monophagous(Phytoseiulus persimilis Athias-Henriot)predatory *** polyphagous species were fed on 2 types of diets,natural prey and alternative *** using 16S rRNA sequencing,we found that diet was the main source of microbiota in predatory mites,while there was no clear pattern affected by prey *** 3 polyphagous predators,host species had a larger impact than prey on microbial *** *** or *** which showed consistency in their microbiota,prey switching significantly affectedβ-diversity of bacterial composition in ***,with 56%of the microbial *** short,our results confirmed the substantial influence of diet on host microbial construction in predatory species,and highlighted species differences in shaping the microbiota which are not necessarily related to prey specialization.

关键词： diet switching feeding habits host-microbial interactions invertebrate microbiota 16S rRNA

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Highly Red Emissive Conjugated Homopolymers Based on Double B←N Bridged Bipyridine Unit

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Chinese Journal of Polymer Science 2024年第8期42卷 1029-1037页

作者： Yu-Yue Gao Kai-Yuan zhang shu-Meng Wang Hui Tong Jun Liu State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Conjugated homopolymers based on six-member rings,e.g.,polyfluorene,always exhibit blue emission and conjugated homopolymers based on five-member rings,e.g.,polythiophene,can give red emission with low *** this work,we report a series of new conjugated homopolymers based on six-member rings with high-efficiency deep-red *** repeating units of the red light emitting homopolymers are double B←N bridged bipyridine(BNBP)with the boron atoms functionalized with diphenyl,borafluorene,and 2,7-di-tert-butyl-borafluorene groups,*** relationship between the chemical structures and the opto-electronic properties of the monomers and the homopolymers has been systematically *** three polymers emit pure red light(λ_(max)=656 nm)or deep red light(λ_(max)=693 nm)with fluorescence quantum efficiency in solution higher than 60%.The polymers can be used as the emitters in solution-processed organic light-emitting diodes with red emission and decent device *** work indicates a new strategy to design highly efficient light emitting conjugated polymers.

关键词： Conjugated homopolymers Double B←N bridged bipyridine(BNBP) Deep-red emission High fluorescent efficiency

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Anti-aging performance improvement and enhanced combustion efficiency of boron via the coating of PDA

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Defence Technology（防务技术） 2024年第3期33卷 399-410页

作者： shuai Ma Qinghai shu Mengyang zhang Hongyu Huang Yansong Shi Xijuan Lv shuai Zhao School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement(MOE) Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic SystemsSchool of PhysicsBeijing Institute of TechnologyBeijing100081China Tangshan Research Institute of Beijing Institute of Technology Tangshan063000HebeiChina

Boron is an ambitious fuel in energetic materials since its high heat release values,but its application is prohibited by low combustion efficiency and oxidization during *** polydopamine(PDA)was introduced into boron particles,investigating the impact of PDA content on the energetic behavior of *** results indicated that the PDA coating formed a fishing net structure on the surface of boron *** heat release results showed that the combustion calorific value of B@PDA was higher than that of the raw ***,the actual combustion heat of boron powder in B@10%PDA increased by 38.08%.Meanwhile,the DSC peak temperature decreased by 100.65℃under similar oxidation rate compared to raw ***,the B@PDA@AP and B@AP composites were prepared,and their combustion properties were *** was demonstrated that B@10%PDA@AP exhibited superior performance in terms of peak pressure and burning time,*** peak pressure is 12.43 kPa more than B@AP and burning time is 2.22 times higher than B@***,the coating of PDA effectively inhibits the oxidization of boron during storage and enhances the energetic behavior of boron and corresponding composites.

关键词： Boron particles Polydopamine Anti-aging performance improvement Heat release

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Elaborative collection of condensed combustion products of solid propellants:Towards a real Solid Rocket Motor(SRM)operational environment

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Chinese Journal of Aeronautics 2024年第1期37卷 77-88页

作者： Wenchao zhang Zhimin FAN Dongliang GOU Yao shu Peijin LIU Aimin PANG Wen AO National Key Laboratory of Solid Rocket Propulsion Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Aerospace Chemical Power Laboratory Xiangyang 441003China

A novel constant-pressure and constant-quenching distance Condensed Combustion Products(CCPs)collection system was developed,coupled with a timing control system,to collect the CCPs formed in the course of burning of aluminum-based composite *** effects of adiabatic graphite plating,collection zone,quenching distance,time series of collection,and propellant burning rate on the microscopic morphology,particle size distribution and unburned aluminum content of CCPs were *** was verified that the graphite plating can provide a high-fidelity high-temperature environment for propellant *** combustion efficiency is improved by 2.44% compared to the bare propellant *** time series of collection has a significant effect on the combustion efficiency of aluminum,and the combustion efficiency of aluminum in the thermal state(1.2-2.4 s)is 2.75% higher than that in the cold state(0-1.2 s).Similarly,the characteristics of the CCPs in different collection zones are *** the quenching distance of 5 mm,the combustion efficiency of aluminum in the core zone(85.39%)is much lower than that in the outer zone(92.07%),while the particle size of the CCPs in the core zone(172μm)is larger than that in the outer zone(41μm).This indicates that the core zone is more likely to produce large-sized and incompletely burned agglomerates during the propellant combustion *** burning rates also lead to a significant difference in particle size distribution and combustion *** burning rates result in higher combustion efficiency.A detailed sequence of the elaborative collection process of CCPs is proposed,mainly including the setting of ignition delay time,burning rate,working pressure,plating length and time series of *** findings of this study are expected to provide a reliable tool for the evaluation of the combustion efficiency of solid propellants.

关键词： Composite propellants Condensed combustion products Aluminum Combustion efficiency Particle size distribution

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Aerodynamic/stealth design of S-duct inlet based on discrete adjoint method

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 725-746页

作者： Jun DENG Ke ZHAO Lin ZHOU Wei zhang Bowen shu Jiangtao HUANG Zhenghong GAO School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Aerospace Technology Institute of China Aerodynamic Research and Development CenterMianyang 621000Sichuan ProvinceChina

It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very *** this study,an aerodynamic/stealth optimization design method for an S-duct inlet is *** upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow *** multilevel fast multipole algorithm(MLFMA)is utilized for the stealth adjoint equation.A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth *** the aerodynamic and stealth characteristics of the inlet are effectively ***,the optimization results are analyzed,and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and crosssectional *** S-duct is smoothed,and the cross-sectional area is increased to improve the aerodynamic characteristics,while it is completely opposite for the stealth *** radar cross section(RCS)is reduced by phase cancelation for low frequency *** method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system.

关键词： S-duct inlet aerodynamic/stealth optimization design discrete adjoint upwind scheme multilevel fast multipole algorithm(MLFMA)

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Local search yields a PTAS for fixed-dimensional k-means problem with penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 351-362页

作者： Fan Yuan Da-Chuan Xu Dong-Lei Du Dong-mei zhang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China Faculty of Management University of New BrunswickFrederictonNB E3B 9Y2Canada School of Computer Science and Technology Shandong Jianzhu UniversityJinan 250101ShandongChina

We study a problem called the k-means problem with penalties(k-MPWP),which is a natural generalization of the typical k-means *** this problem,we have a set D of client points in R^(d),a set F of possible centers in R^(d),and a penalty cost Pj>O for each point j∈*** are also given an integer k which is the size of the center point *** want to find a center point set S■F with size k,choose a penalized subset of clients P■D,and assign every client in D\P to its open *** goal is to minimize the sum of the squared distances between every point in D\P to its assigned centre point and the sum of the penalty costs for all clients in *** using the multi-swap local search technique and under the fixed-dimensional Euclidean space setting,we present a polynomial-time approximation scheme(PTAS)for the k-MPWP.

关键词： Approximation algorithm k-means Local search Penalty

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Global Spillovers of China's Monetary Policy

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China & World Economy 2024年第3期32卷 1-30页

作者： Wenni Lei Dongzhou mei Mi zhang School of Economics Minzu University of ChinaChina School of International Trade and Economics Central University of Finance and EconomicsChina

Spillovers from China's monetary policy have become increasingly obvious with China's growing importance in the global economy and its close economic and trade ties with the *** study establishes a proxy structure vector autoregression model to investigate the magnitude and transmission channel of spillovers from China to global and regional economies,taking advantage of high-frequency changes in asset prices in the financial markets to identify monetary policy *** analysis reveals that China's monetary policy can affect the global economy by influencing international trade and commodity prices but there is no evidence of China's monetary policy affecting global financial *** in China's monetary policy can cause a decline in world output whereas expansion in monetary policy can support global trade and *** study also finds that the response of emerging Asian economies to China's monetary policy shock was nearly twice that of developed economies,while the transmission path did not *** results of this study are consistent with the stylized fact that China's monetary policy plays an important role in the global trade and commodity cycle,although it does not drive the global financial cycle.

关键词： China's monetary policy commodity prices external instruments global trade spillovers

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Prediction for permeability index of blast furnace based on VMD-PSO-BP model

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Journal of Iron and Steel Research International 2024年第3期31卷 573-583页

作者： Xiao-jie Liu Yu-jie zhang Xin Li Zhi-feng zhang Hong-yang Li Ran Liu shu-jun Chen School of Metallurgy and Energy North China University of Science and TechnologyTangshan 063210HebeiChina Chengde Branch HBIS Group Co.Ltd.Chengde 067000HebeiChina

The permeability index is one of the important production indicators to monitor the operation of blast *** is crucial to grasp the trends of changes in the new permeability index in *** the complex vibration spectrum of the permeability index,a prediction model of the permeability index based on the VMD-PSO-BP(variational mode decomposition-particle swarm optimization-back propagation)method was ***,the key factors that affect the permeability index of blast furnace were studied from multiple ***,the permeability index was divided into multiple sub-modes based on the difference of frequency bands by the VMD algorithm,and a PSO-BP prediction model was established for each ***,the prediction results of each sub-mode were summed to obtain the final *** results show that the composite prediction accuracy by using the VMD algorithm is 3%higher than that of the traditional prediction method,which has better applicability.

关键词： Big data-Blast furnace Air permeability Variational mode decomposition Particle swarm optimization Back propagation Model prediction

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