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Degeneration of foundation cushion species induced by ecological constraints can cause massive changes in alpine plant communities

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Science china(Life Sciences) 2024年第4期67卷 789-802页

作者： Jianguo Chen Xufang Chen Lishen Qian Yazhou Zhang Bo Li Honghua Shi Lu Sun Christian Schöb Hang Sun Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China College of Resources and Environment Yunnan Agricultural UniversityKunming 650500China Área de Biodiversidad y Conservación Universidad Rey Juan CarlosMóstoles 28933Spain

Foundational cushion plants can re-organize community structures and sustain a prominent proportion of alpine biodiversity,but they are sensitive to climate *** loss of cushion species can have broad consequences for associated *** potential plant community changes with the population dynamics of cushion plants remain,however,*** eight plant communities along a climatic and community successional gradient,we assessed cushion population dynamics,the underlying ecological constraints and hence associated plant community changes in alpine communities dominated by the foundational cushion plant Arenaria *** population dynamics of Arenaria are attributed to ecological constraints at a series of life history *** functions are constrained by increasing associated beneficiary plants;subsequent seedling establishment is constrained by temperature,water and light availability,extreme climate events,and interspecific competition;strong competitive exclusion may accelerate mortality and degeneration of cushion *** with cushion dynamics,species composition,abundance and community structure gradually *** cushion plants completely degenerate,previously cushion-dominated communities shift to relatively stable communities that are overwhelmingly dominated by *** warming may accelerate the degeneration process of *** of this foundational cushion plant will possibly induce massive changes in alpine plant communities and hence ecosystem functions in alpine *** assessment of the population dynamics of foundation species is critical for an effective conservation of alpine biodiversity.

关键词： alpine ecosystem biodiversity change climate change plant community dynamics foundation species global warming population dynamics

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Impacts of high temperature,relative air humidity,and vapor pressure deficit on the seed set of contrasting maize genotypes during flowering

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Journal of Integrative Agriculture 2024年第9期23卷 2955-2969页

作者： Xin Dong Baole Li Zhenzhen Yan Ling Guan Shoubing Huang Shujun Li Zhiyun Qi Ling Tang Honglin Tian Zhongjun Fu Hua Yang Chongqing Academy of Agricultural Sciences Chongqing 401329China College of Agronomy and Biotechnology China Agricultural UniversityBeijing 100193China

Heat stress is a major constraint to current and future maize production at the global *** and female reproductive organs both play major roles in increasing seed set under heat stress at flowering,but their relative contributions to seed set are *** this study,a 2-year field experiment including three sowing dates in each year and 20 inbred lines was *** set,kernel number per ear,and grain yield were all reduced by more than 80%in the third sowing dates compared to the first sowing *** viability,silk emergence ratio,and anthesis-silking interval were the key determinants of seed set under heat stress;and their correlation coefficients were 0.89^(***),0.65^(***),and-0.72^(***),*** pressure deficit(VPD)and relative air humidity(RH)both had significant correlations with pollen viability and the silk emergence *** RH can alleviate the impacts of heat on maize seed set by maintaining high pollen viability and a high silk emergence *** a warming climate from 2020 to 2050,VPD will decrease due to the increased *** on their pollen viability and silk emergence ratios,the 20 genotypes fell into four different *** group with high pollen viability and a high silk emergence ratio performed better under heat stress,and their performance can be further improved by combining the improved flowering pattern traits.

关键词： maize pollen viability silk emergence heat stress relative humidity

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KHCO_3 activated carbon microsphere as excellent electrocatalyst for VO^(2+)/VO_2^+ redox couple for vanadium redox flow battery

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Journal of Energy Chemistry 2019年第2期28卷 103-110页

作者： Chen Zhao Yuehua Li Zhangxing He Yingqiao Jiang Lu Li Fengyun Jiang Huizhu Zhou Jing Zhu Wei Meng Ling Wang Lei Dai School of Chemical Engineering North China University of Science and Technology State Key Laboratory Breeding Base of Nuclear Resources and Environment East China University of Technology Hebei Province Key Laboratory of Photocatalytic and Electrocatalytic Materials for Environment North China University of Science and Technology

In this paper,carbon microsphere prepared by hydrothermal treatment was activated by KHCO_3 at high temperature,and employed as the catalyst for VO^(2+)/VO_2^+redox reaction for vanadium redox flow battery(VRFB).Carbon microsphere can be etched by KHCO_3 due to the reaction between the pyrolysis products of KHCO_3 and carbon ***,KHCO_3 activation can bring many oxygen functional groups on carbon microsphere,further improving the wettability of catalyst and increasing the active *** electrocatalytic properties of carbon microsphere from hydrothermal treatment are improved by high temperature carbonization,and can further be enhanced by KHCO_3 *** carbon microsphere samples,the VO^(2+)/VO_2^+redox reaction exhibits the highest electrochemical kinetics on KHCO_3 activated *** cell using KHCO_3 activated carbon microsphere as the positive catalyst demonstrates higher energy efficiency and larger discharge capacity,especially at high current *** results reveal that KHCO_3 activated carbon microsphere is an efficient,low-cost carbon-based catalyst for VO^(2+)/VO_2^+redox reaction for VRFB system.

关键词： Energy storage Vanadium redox flow battery Carbon microsphere KHCO3 Etching

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Effects of growth temperature on μc-Si:H films prepared by plasma assistant magnetron sputtering

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Rare Metals 2012年第2期31卷 193-197页

作者： Su, Yuanjun Dond, Chuang Zhu, Ming Xu, Jun Fan, Penghui Key Laboratory of Materials Modification by Laser Ion and Electron Beams Ministry of Education Dalian University of Technology Dalian 116024 China Nissin Electric-Dalian University of Technology Joint R&D Center Dalian University of Technology Dalian 116024 China

Hydrogenated microcrystalline silicon thin films (μc-Si:H) were deposited by plasma assistant magnetron sputtering in Ar-H 2 gas mixture. The effects of growth temperature from 150 to 450 C on properties of deposited Si films were investigated at two different hydrogen diluted gases with [H 2 ]/([Ar]+[H 2 ]) of 10% and 50% at 3 Pa. The crystallinity of Si films examined by Raman scattering exhibited higher degrada- tion by lowering growth temperature from 250 to 150 C in low hydrogen diluted gas of 10% than that in high hydrogen diluted gas of 50%. The IR absorption band around 845 and 890 cm 1 as well as calculated concentration of bonded hydrogen showed more obvious decrease of samples deposited in low hydrogen diluted gas of 10% than that in high hydrogen diluted gas of 50%. The optical band gasps of both groups of samples measured by ultraviolet-visible optical absorption were decreased with increasing temperature in both gas conditions.

关键词： microcrystalline silicon Raman scattering hydrogen-silicon bonding optical band gap

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High-pressure structure and elastic properties of tantalum single crystal:First principles investigation

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Chinese Physics B 2016年第12期25卷 350-356页

作者：顾建兵王臣菊张旺玺孙斌刘国群刘丹丹杨向东 School of Materials and Chemical Engineering Zhongyuan University of Technology College of Science Zhongyuan University of Technology Institute of Atomic and Molecular Physics Sichuan University

Since knowledge of the structure and elastic properties of Ta at high pressures is critical for addressing the recent controversies regarding the high-pressure stable phase and elastic properties, we perform a systematical study on the highpressure structure and elastic properties of the cubic Ta by using the first-principles method. Results show that the initial body-centered cubic phase of Ta remains stable even up to 500 GPa and the high-pressure elastic properties are excellent/y consistent with the available experimental results. Besides, the high-pressure sound velocities of the single- and polycrystals Ta are also calculated based on the elastic constants, and the predications exhibit good agreement with the existing experimental data.

关键词： high-pressure structure elastic properties sound velocities density functional theory

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Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

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Chinese Physics B 2016年第11期25卷 526-529页

作者：刘文峰张敏刚张克维张海杰许小红柴跃生 School of Materials Science and Engineering Institute of Advanced Materials Taiyuan University of Science and Technology Institute of Materials Chemistry Shanxi Normal University

Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si（100） substrates,and subsequently annealed in vacuum at different temperatures for different *** is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta ***,the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the *** high coercivity of 24.1 kOe（1 Oe = 79.5775 A/m） and remanence ratio（remanent magnetization/saturation magnetization）of 0.94 can be obtained in a Ta/Nd（250 nm）/NdFeB（600 nm）/Nd（250 nm）/Ta film annealed for 3 min at 1023 *** addition,the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as *** excellent thermal stability can be achieved in a Ta/Nd（250 nm）/NdFeB（600 nm）/Nd（250 nm）/Ta film annealed at1023 K.

关键词： annealing NdFeB annealed coercivity magnetization magnetron sputtering vacuum subsequently magnetometer

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Preparation of ZnO/GO composite material with highly photocatalytic performance via an improved two-step method

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Chinese Chemical Letters 2013年第6期24卷 518-520页

作者： Ya-Li Chen Chun-E.Zhang Chao Deng Peng Fei Ming Zhong Bi-Tao Su Key Laboratory of Eco-Environment-Related Polymer Materials Ministry of Education of ChinaKey Laboratory of Polymer Materials of Gansu ProvinceCollege of Chemistry and Chemical EngineeringNorthwest Normal University

ZnO/graphene oxide（ZnO/GO） composite material,in which ZnO nanoparticles were densely coated on the GO nanosheets,was successfully prepared by an improved two-step method and characterized by IR, XRD,TEM,and UV-vis *** improved photocatalytic property of the ZnO/GO composite material,evaluated by the photocatalytic degradation of methyl orange（MO） under UV irradiation,is ascribed to the intimate contact between ZnO and GO,the enhanced adsorption of MO,the quick electron transfer from excited ZnO particles to GO sheets and the activation of MO molecules viaπ-πinteraction between MO and GO.

关键词： ZnO/GO composite material Improved two-step method Characterization Enhanced adsorptive and photocatalytic property

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Effects of ion bombardment on microcrystalline silicon growth by inductively coupled plasma assistant magnetron sputtering

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Science china(Physics,Mechanics & Astronomy) 2012年第11期55卷 2070-2075页

作者： HE YangYang SU YuanJun ZHU Ming CAO BaoSheng DONG Bin School of Physics and Materials Engineering Dalian Nationalities UniversityDalian 116600China Key Laboratory of Materials Modification by Laser Ion and Electron BeamsDalian University of TechnologyMinistry of EducationDalian 116024China

Hydrogenated microcrystalline silicon （mc-Si：H） thin films were deposited by inductively coupled plasma assistant magnetron sputtering （ICP-MS） in an Ar-H2 gas mixture. The role of ion bombardment in the growth of mc-Si：H films was studied with increasing negative bias voltages on the substrate holder from 0 to -100 V. Raman scattering, X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy and transmission electron microscopy （TEM） were performed to investigate the microstructure changes of deposited Si films. Raman scattering showed that the high energy ion bombardment resulted in crystalline degradation of Si films. The XRD results showed the decrease and even elimination of preferential growth orientation of crystalline Si films with ion bombardment energy increase. The SiH bonding configuration changes and the increase of bonded hydrogen concentration were determined with the analysis of FTIR spectra. Furthermore, the dramatic evolution of cross-sectional morphology of Si thin films was detected by TEM observation.

关键词： hydrogenated microcrystalline silicon ion bombardment magnetron sputtering silicon-hydrogen bonding configuration

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Spin-polarized electronic properties of NiHe_(0.25) under pressure

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Chinese Physics B 2009年第3期18卷 1201-1206页

作者：伞晓娇刘志明马琰铭崔田刘冰冰邹广田 National Laboratory of Superhard Materials Jilin University Center for Condensed Matter Science and Technology Department of PhysicsHarbin Institute of Technology

This paper studies the effects of He atom on the spin-polarized electronic properties of nickel under pressures using ab initio pseudopotential plan-wave method. Under high pressures, the compound of NiHeo.25 can exist and helium- bubble can not create in Ni. A pressure-induced ferromagnetic to paramagnetic phase transition has been predicted in NiHeo.25 at about 218 GPa. It is found that under pressures, the magnetic property of Ni atoms is more strongly affected by He atom than by H atom and that the behaviour of He atom in Ni are completely different from that of H atom, like the bonding characteristics and the electron transfer.

关键词： plane-wave method interaction potential electronic structure

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Study of the influences of rotary table speed on stick-slip vibration of the drilling system

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Petroleum 2015年第4期1卷 382-387页

作者： Liping Tang Xiaohua Zhu Changshuai Shi Jian Tang Daping Xu School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China Department of Gas Tarim Oilfield CompanyKorlaXinjiang 841000China School of Mechanical Engineering Sichuan University of Science and EngineeringZigongSichuan 643000China

Stick-slip vibration presents one of the major causes of drilling problems,such as premature tool failures,low drilling efficiency and poor wellbore *** objective of this work is to investigate the influences of rotary table speed(RTS)on stick-slip phenomenon of the drilling *** this study,the drilling system is treated as a lumped torsional pendulum model of which the bit/rock interaction is regarded as Coulomb *** analyzing cases with different RTS,two types of vibrations on the bit are found:stick-slip vibration and uniform *** an increase in the RTS,the stick-slip vibration on the drill bit disappears once the RTS arrives at its critical *** the cases that stick-slip vibrations occur,the phase trajectories converge toward a limit *** the cases that stick-slip vibration does not appear,the drill bit tends to stabilize at a uniform motion and the phase trajectories correspond to contracting spirals observed in the phase plane.

关键词： Stick-slip vibration Rotary table speed Drillstring Drill bit Frictional torque Limit cycle

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