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A new diterpenoid from the stem bark of Populus davidiana

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Chinese Chemical Letters 2008年第9期19卷 1080-1082页

作者： xin feng zhang Xiang Li Byung Sun Min Ki Hwan Bae College of Forestry and Biotechnology Zhejiang Forestry University Hangzhou 311300 China Saskatoon Research Center Agriculture and Agri-Food Canada 107 Science Place SK Canada STN OX2 College of Pharmacy Catholic University ofDaegu Gyeongbuk 712-702 Republic of Korea College of Pharmacy Chungnam National University Daejeon 305-764 Republic of Korea

A new diterpenoid, named populusol A （1）, was isolated from the methanolic extraction of the stem bark of Populus davidiana. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HRFAB-MS s... 详细信息

关键词： Populus davidiana Diterpenoid Populusol A

Threshold Selection and Resource Allocation for Quantized Identification

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Journal of Systems Science & Complexity 2024年第1期37卷 204-229页

作者： WANG Ying LI xin ZHAO Yanlong zhang Ji-feng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper is concerned with the optimal threshold selection and resource allocation problems of quantized identification, whose aims are improving identification efficiency under limited resources. Firstly, the first-order asymptotically optimal quantized identification theory is extended to the weak persistent excitation condition. Secondly, the characteristics of time and space complexities are established based on the Cramér-Rao lower bound of quantized systems. On these basis, the optimal selection methods of fixed thresholds and adaptive thresholds are established under aperiodic signals, which answer how to achieve the best efficiency of quantized identification under the same time and space complexity. In addition, based on the principle of maximizing the identification efficiency under a given resource, the optimal resource allocation methods of quantized identification are given for the cases of fixed thresholds and adaptive thresholds, respectively, which show how to balance time and space complexity to realize the best identification efficiency of quantized identification.

关键词： Quantized output resource allocation system identification threshold selection.

A new salicin derivative from the stem bark of Populus davidiana

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Chinese Chemical Letters 2009年第11期20卷 1321-1323页

作者： xin feng zhang Xiang Li Zhu Yan Jin Ping Si Ki Hwan Bae College of Forestry and Bioscience Technology Zhejiang Forestry University Hangzhou 311300 China Saskatoon Research Center Agriculture and Agri-Food Canada 107 Science Place SK STN OX2 Canada College of Pharmacy Chungnam National University Daejeon 305-764 Republic of Korea

Phytochemical study on the BuOH-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of a new salicin derivative （1）, named davidianoside. The structure was elucidated on the basis of ext... 详细信息

关键词： Populus davidiana Salicin derivative Davidianoside

Davis's Inequalities for Two-Parameter Banach Space Valued Strong Martingales and Geometrical Properties of Banach Spaces

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Wuhan University Journal of Natural Sciences 2000年第2期5卷 131-136页

作者： YE Chen GAN Shi xin zhang feng College of Mathematics and Computer Science Wuhan UniversityWuhan 430072China

In this paper we investigated theL 1 norm inequalities of theP square and the maximal functions of two-parameterB-valued strong martingales, which can be applied to characterizep-smoothness andq-convexity of Banach sp... 详细信息

关键词： two parameterB valued strong martingale Davis’s inequality p smoothable q convexifiable

SYNTHESIS AND CHARACTERIZATION OF POLYSILOXANE CONTAINING OLIGO(OXYETHYLENE)SULFATE SALT

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Chinese Journal of Polymer Science 2000年第2期18卷 109-113页

作者： Shu-wen Hu Zheng-cheng zhang FanYi Shi-bi Fang xin-feng zhang Fu-mian Li Department of Chemistry, Peking University, Beijing 100871, China 中科院化学所北京北京大学北京

Solvent-free polymeric alkali-metal ion conductors, consisting of a comb-like polysiloxane with oligo(oxyethylene) side chains and pendant sulfate groups were synthesized by the hydrosilylation of allyl oligo(oxyethylene) sulfate salt and allyl methoxy oligo(oxyethylene) with poly(methylhydrosiloxane). The factors influncing the ionic conductivity of the resulting polymer such as the electrolyte content and the nature of the alkali-metal were investigated. The temperature dependence of conductivity was determined, and the ionic conductivity of the polymer follows the Vogel-Tammann-Fulcher (VTF) equation.

关键词： hydrosilylation electrolytes ionic conductivity

Prospects for weighing neutrinos in interacting dark energy models using joint observations of gravitational waves andγ-ray bursts

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Chinese Physics C 2024年第9期48卷 225-233页

作者： Lu feng Tao Han Jing-Fei zhang xin zhang College of Physical Science and Technology Shenyang Normal UniversityShenyang 110034China Key Laboratory of Cosmology and Astrophysics(Liaoning Province)&Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of Education) Northeastern UniversityShenyang 110819China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China

Cosmological observations can be used to weigh neutrinos,but this method is model-dependent,with results relying on the cosmological model *** we consider interactions between dark energy and dark matter,the neutrino mass constraints differ from those derived under the standard *** the contrary,gravitational wave(GW)standard siren observations can measure absolute cosmological distances,helping to break parameter degeneracies inherent in traditional cosmological observations,thereby improving constraints on neutrino *** paper examines the constraints on neutrino mass within interacting dark energy(IDE)models and explores how future GW standard siren observations could enhance these *** multi-messenger GW observations,we consider the joint observations of binary neutron star mergers by third-generation ground-based GW detectors and shortγ-ray burst observations by missions similar to the THESEUS satellite *** current cosmological observations(CMB+BAO+SN),we obtain an upper limit on the neutrino mass in the IDE models of 0.15(or 0.16)*** the inclusion of GW data,the upper limit on the neutrino mass improves to 0.14 *** indicates that in the context of IDE models,the improvement in neutrino mass constraints from GW observations is relatively ***,GW observations significantly enhance the constraints on other cosmological parameters,such as matter density parameter,the Hubble constant,and coupling strength between dark energy and dark matter.

关键词： interacting dark energy neutrino mass gravitational wave standard siren cosmology

Synchronous deprotonation–protonation for mechanically robust chitin/aramid nanofibers conductive aerogel with excellent pressure sensing, thermal management, and electromagnetic interference shielding

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Nano Research 2024年第3期17卷 2038-2049页

作者： xinxin zhang Kunpeng Qian Jianhui Fang Sineenat Thaiboonrod Miao Miao xin feng Department of Chemistry College of SciencesShanghai UniversityShanghai 200444China Research Center of Nano Science and Technology College of SciencesShanghai UniversityShanghai 200444China School of Materials Sciences and Engineering Shanghai UniversityShanghai 200444China National Nanotechnology Center(NANOTEC) National Science and Technology Development Agency(NSTDA)Thailand Science ParkPathum Thani 12120Thailand

Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors,electromagnetic shielding,and so ***,the poor mechanical properties of the emerging nanofibers-based aerogels are limited in practical *** this work,we developed a synchronous deprotonation–protonation method in the KOH/dimethyl sulfoxide(DMSO)system at room temperature for achieving chitin cross-linked aramid nanofibers(CANFs)rather than chitin nanofibers(ChNFs)and aramid nanofibers(ANFs)separately by using chitin and aramid pulp as raw *** freeze-drying process,the cross-linked chitin/aramid nanofibers(CA)aerogel exhibited the synergetic properties of ChNF and ANF by the dual-nanofiber compensation *** mechanical stress of CA aerogel was 170 kPa at 80%compressive strain,increased by 750%compared with pure ChNF ***,the compressibility of CA aerogel was somewhat improved compared to ANF *** enhancement verified that the crosslinking reaction between ANF and ChNF during the synchronous deprotonation process was ***,the conductive aerogels with uniform porous structure(CA-M)were successfully obtained by vacuum impregnating CA aerogels in Ti_(3)C_(2)T_(x) MXene solution,displaying low thermal conductivity(0.01 W/(m·K)),high electromagnetic interference(EMI)shielding effectiveness(SE)(75 dB),flame retardant,and heat ***,the as-obtained CA-M aerogels were also applied as a pressure sensor with excellent compression cycle stability and superior human motion monitoring *** a result,the dual-nanofiber based conductive aerogels have great potentials in flexible/wearable electronics,EMI shielding,flame retardant,and heat insulation.

关键词： synchronous deprotonation–protonation electromagnetic interference(EMI)shielding flame retardant heat insulation pressure sensing

Central environmental protection inspection and carbon emission reduction: A tripartite evolutionary game model from the perspective of carbon neutrality

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Petroleum Science 2024年第3期21卷 2139-2153页

作者： Zhen-Hua zhang Dan Ling Qin-xin Yang Yan-Chao feng Jing Xiu School of Economics Lanzhou UniversityLanzhou 730000GansuChina Institute of Green Finance Lanzhou UniversityLanzhou 730000GansuChina School of Management Lanzhou UniversityLanzhou 730000GansuChina School of Business Zhengzhou UniversityZhengzhou 450001HenanChina Institute of Economics Jilin Academy of Social SciencesChangchun130033JilinChina

Since the carbon neutrality target was proposed,many countries have been facing severe challenges to carbon emission reduction *** study is conducted using a tripartite evolutionary game model to explore the impact of the central environmental protection inspection(CEPI)on driving carbon emission reduction,and to study what factors influence the strategic choices of each party and how they interact with each *** research results suggest that local governments and manufacturing enterprises would choose strategies that are beneficial to carbon reduction when CEPI *** the initial willingness of all parties increases 20%,50%—80%,the time spent for the whole system to achieve stability decreases from 100%,60%—30%.The evolutionary result of“thorough inspection,regulation implementation,low-carbon management”is the best strategy for the tripartite evolutionary ***,the smaller the cost and the larger the benefit,the greater the likelihood of the three-party game stability strategy *** study has important guiding significance for other developing countries to promote carbon emission reduction by environmental policy.

关键词： Central environmental protection inspection Local government Manufacturing enterprise Tripartite evolutionary game Carbon emission reduction

Exceptional electrostrain with minimal hysteresis and superior temperature stability under low electric field in KNN-based lead-free piezoceramics

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Journal of Advanced Ceramics 2024年第3期13卷 364-372页

作者： Huan Liu Yijin Hao Ziqi Yang Tianyi feng Bin Su xin zhang Mengping Xue Bo-Ping zhang Jing-feng Li Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant ***,attaining a high electrostrain with remarkable temperature stability and minimal hysteresis under low electric fields has remained a significant *** address this long-standing issue,we have employed a collaborative approach that combines defect engineering,phase engineering,and relaxation *** LKNNS-6BZH ceramic,when sintered at T_(sint)=1170℃,demonstrates an impressive electrostrain with a d_(33) value of 0.276%and 1379 pm·V^(-1)under 20 kV·cm^(-1),which is comparable to or even surpasses that of other lead-free and Pb(Zr,Ti)O_(3)***,the electrostrain performance of this ceramic remains stable up to a temperature of 125℃,with the lowest hysteresis observed at 9.73%under 40 kV·cm^(-1).These excellent overall performances are attributed to the presence of defect dipoles involving V′_(A)-V∙∙_(O) and B′_(Nb)-V∙∙O,the coexistence of R-O-T multiphase,and the tuning of the trade-off between long-range ordering and local *** work provides a lead-free alternative for piezoelectric actuators and a paradigm for designing piezoelectric materials with outstanding comprehensive performance under low electric fields.

关键词： lead-free piezoelectric ceramics temperature stability electrostrain potassium sodium niobate low hysteresis