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Polymeric piezoelectric accelerometers with high sensitivity,broad bandwidth,and low noise density for organic electronics and wearable microsystems

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Microsystems & Nanoengineering 2024年第3期10卷 63-74页

作者： Chang Ge Edmond Cretu The Department of Electrical and Computer Engineering The University of British ColumbiaVancouverBCCanada

Piezoelectric accelerometers excel in vibration *** the emerging trend of fully organic electronic microsystems,polymeric piezoelectric accelerometers can be used as vital front-end components to capture dynamic signals,such as vocal vibrations in wearable speaking assistants for those with speaking ***,high-performance polymeric piezoelectric accelerometers suitable for such applications are *** organic compounds such as PVDF have inferior properties to their inorganic counterparts such as ***,most existing polymeric piezoelectric accelerometers have very unbalanced performance *** often sacrifice resonance frequency and bandwidth for a flat-band sensitivity comparable to those of PZT-based accelerometers,leading to increased noise density and limited application *** this study,a new polymeric piezoelectric accelerometer design to overcome the material limitations of PVDF is *** new design aims to simultaneously achieve high sensitivity,broad bandwidth,and low *** samples were manufactured and characterized,demonstrating an average sensitivity of 29.45 pC/g within a±10 g input range,a 5%flat band of 160 Hz,and an in-band noise density of 1.4μg/√*** results surpass those of many PZT-based piezoelectric accelerometers,showing the feasibility of achieving comprehensively high performance in polymeric piezoelectric accelerometers to increase their potential in novel applications such as organic microsystems.

关键词： piezoelectric polymeric overcome

Selective extinction and habitat nestedness are the main drivers of lizard nestedness in the Zhoushan Archipelago

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Current Zoology 2024年第2期70卷 244-252页

作者： Minchu Zhang Chaonan Tang Qing Zhang Chengxiu Zhan Chuanwu Chen Yanping Wang Laboratory of island Biogeography and Conservation Biology College of Life SciencesNanjing Normal UniversityNanjing 210023China

Nested subset pattern(nestedness)is an important part of the theoretical framework of island biogeography and community ***,most previous studies often used nestedness metrics or randomization algorithms that are vulnerable to type I *** this study,we inves-tigated the nestedness of lizard assemblages on 37 islands in the Zhoushan Archipelago,*** used the line-transect method to survey species occurrence,abundance,and habitat types of lizards on 37 islands during 2 breeding seasons in 2021 and *** applied the nested metric WNODF and the conservative rc null model to control for type I error and quantify the significance of *** rank cor relations were used to evaluate the role of 4 habitat variables(island area,2 isolation indices,and habitat diversity)and 4 ecological traits(body size,geographic range size,clutch size,and minimum area requirement)in generating *** results of WNODF analyses showed that lizard assemblages were significantly *** habitat-by-site matrix estimated by the program NODF was also significantly nested,support-ing the habitat nestedness *** nestedness of lizard assemblages were significantly correlated with island area,habitat *** size,and minimum area ***,our results suggest that selective extinction and habitat nestedness were the main drivers of lizard nestedness in our *** contrast,the nestedness of lizard assemblages was not due to passive sampling or selective *** maximize the number of species preserved,our results indicate that we should protect both large islands with diverse habitats and species with largearea requirement and clutch size.

关键词： clutch size habitat nestedness lizards minimum area requirement nestedness selective extinction WNODF Zhoushan Archipelago.

Evolution of biomass particles during pelletization process

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Particuology 2024年第3期86卷 182-187页

作者： Hamid Rezaei Maryam Tajilrou Jun Sian Lee Kanages Singaraveloo Anthony Lau Shahab Sokhansanj Biomass and Bioenergy Research Group Department of Chemical and Biological EngineeringUniversity of British ColumbiaVancouverCanada

Pulverizing is an essential unit operation in co-firing biomass with *** are only compatible with pellet forms of fibrous biomass materials and crush them down to their original forming particle *** is why the data on the size distribution of the particles forming a biomass pellet is crucial to achieving optimum combustion *** current study determines the internal particle size distribution of pellets after wet disintegration,following Iso 17830 standard,and aims to suggest improvements to the mentioned standard based on new measured *** were carried out on white wood pellets(no bark)and brown wood pellets containing bark at four water temperatures:20,40,60,and 95℃,with or without *** particle size distribution of the pre-pelletizer wood particles was also measured and compared with particles in the formed *** water temperature of 20℃ was found to be adequate for the complete disintegration of pellets,and no mechanical stirring was *** 30% of particles in the disintegrated pellets were 0.5-1.0 *** changes the particle size distribution to smaller *** disintegrated bark pellets contained more fines than white pellets.

关键词： Wood pellets Particle sizes distribution Wet disintegration Stirring Water temperature

Analyzing the Wind-Dominant Electricity Market under Coexistence of Regulated and Deregulated Power Trading

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Energy Engineering 2024年第8期121卷 2093-2127页

作者： Yirui Li Dongliang Xiao Haoyong Chen Weijun Cai Josue Campos do Prado School of Electric Power South China University of TechnologyGuangzhou510641China School of Engineering and Computer Science Washington State University VancouverVancouver98686USA School of Automation Guangdong University of TechnologyGuangzhou510006China

Currently,both regulated and deregulated power trading exist in China’s power system,which has caused imbalanced funds in the electricity *** this paper,a simulation analysis of the electricity market with wind energy resources is conducted,and the calculation methods of unbalanced funds are investigated *** detail,the calculation formulas of unbalanced funds are illustrated based on their definition,and a two-track electricity market clearing model is ***,the concept of the dual-track system is explained,and the specific calculation formulas of various types of unbalanced funds are ***,considering the renewable energy consumption,the market clearing model based on DC power flow is constructed and solved;by combining fitting methods of mid-and long-term curves,the unbalanced funds are calculated based on clearing results and formulas.

关键词： Dual-track system electricity market renewable energy unbalanced funds

Precision tuning of highly efficient Pt-based ternary alloys on nitrogen-doped multi-wall carbon nanotubes for methanol oxidation reaction

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Journal of Energy Chemistry 2024年第1期88卷 242-251,I0006页

作者： Xingqun Zheng Zhengcheng Wang Qian Zhou Qingmei Wang Wei He Shun Lu College of Safety Engineering Chongqing University of Science&TechnologyChongqing 401331China College of Chemistry and Chemical Engineering Chongqing UniversityChongqing 400044China School of Chemistry and Chemical Engineering Guizhou UniversityGuizhou 550025GuiyangChina Department of Chemistry University of Rhode IslandKingston 02881Rhode IslandUnited States Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China

The electrochemical methanol oxidation is a crucial reaction in the conversion of renewable *** enable the widespread adoption of direct methanol fuel cells(DMFCs),it is essential to create and engineer catalysts that are both highly effective and robust for conducting the methanol oxidation reaction(MOR).In this work,trimetallic PtCoRu electrocatalysts on nitrogen-doped carbon and multi-wall carbon nanotubes(PtCoRu@NC/MWCNTs)were prepared through a two-pot synthetic *** acceleration of CO oxidation to CO_(2) and the blocking of CO reduction on adjacent Pt active sites were attributed to the crucial role played by cobalt atoms in the as-prepared *** precise control of Co atoms loading was achieved through precursor *** physicochemical techniques were employed to analyze the morphology,element composition,and electronic state of the *** investigations and theoretical calculations confirmed that the Pt_(1)Co_(3)Ru_(1)@NC/MWCNTs exhibit excellent electrocatalytic performance and durability for the process of *** enhanced MOR activity can be attributed to the synergistic effect between the multiple elements resulting from precisely controlled Co loading content on surface of the electrocatalyst,which facilitates efficient charge *** interaction between the multiple components also modifies the electronic structures of active sites,thereby promoting the conversion of intermediates and accelerating the MOR ***,achieving precise control over Co loading in PtCoRu@NC/MWCNTs would enable the development of high-performance catalysts for DMFCs.

关键词： Ternary alloys Electrocatalysts Methanol oxidation reaction Electron transfer Theoretical calculations

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SRMD:Sparse Random Mode Decomposition

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Communications on Applied Mathematics and Computation 2024年第2期6卷 879-906页

作者： Nicholas Richardson Hayden Schaeffer Giang Tran university of Waterloo WaterlooONCanada university of British Columbia VancouverBCCanada university of California Los AngelesCAUSA

Signal decomposition and multiscale signal analysis provide many useful tools for timefrequency *** proposed a random feature method for analyzing time-series data by constructing a sparse approximation to the *** randomization is both in the time window locations and the frequency sampling,which lowers the overall sampling and computational *** sparsification of the spectrogram leads to a sharp separation between time-frequency clusters which makes it easier to identify intrinsic modes,and thus leads to a new data-driven mode *** applications include signal representation,outlier removal,and mode *** benchmark tests,we show that our approach outperforms other state-of-the-art decomposition methods.

关键词： Sparse random features Signal decomposition Short-time Fourier transform

Unexpected divergence in magnetoreceptor MagR from robin and pigeon linked to two sequence variations

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Zoological Research 2024年第1期45卷 69-78页

作者： Shun Wang Peng Zhang Fan Fei Tianyang Tong Xiujuan Zhou Yajie Zhou Jing Zhang Mengke Wei Yanqi Zhang Lei Zhang Yulong Huang Lin Zhang Xin Zhang Tiantian Cai Can Xie Institutes of Physical Science and Information Technology Anhui UniversityHefeiAnhui 230039China High Magnetic Field Laboratory Hefei Institutes of Physical ScienceChinese Academy of SciencesScience IslandHefeiAnhui 230031China Science island Branch of Graduate School University of Science and Technology of ChinaHefeiAnhui 230036China Department of Anatomy Anhui Medical UniversityHefeiAnhui 230032China Department of Mechanical and Aerospace Engineering University at BuffaloState University of New YorkBuffaloNY 14260 USA International Magnetobiology Frontier Research Center Science IslandHefeiAnhui 230031China

Birds exhibit extraordinary mobility and remarkable navigational skills,obtaining guidance cues from the Earth’s magnetic field for orientation and long-distance *** species also show tremendous diversity in navigation strategies,with considerable differences even within the same taxa and among individuals from the same *** highly conserved iron and iron-sulfur cluster binding magnetoreceptor(MagR)protein is suggested to enable animals,including birds,to detect the geomagnetic field and navigate ***,MagR is also implicated in other functions,such as electron transfer and biogenesis of iron-sulfur clusters,raising the question of whether variability exists in its biochemical and biophysical features among species,particularly *** the current study,we conducted a comparative analysis of MagR from two different bird species,including the migratory European robin(Erithacus rubecula)and the homing pigeon(Columba livia).Sequence alignment revealed an extremely high degree of similarity between the MagRs of these species,with only three sequence ***,two of these variations underpinned significant differences in metal binding capacity,oligomeric state,and magnetic *** findings offer compelling evidence for the marked differences in MagR between the two avian species,potentially explaining how a highly conserved protein can mediate such diverse functions.

关键词： Homing and migration Animal navigation Magnetoreceptor(MagR) Diverse navigation pattern Conserved protein

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Enhanced conductivity and weakened magnetism in Pb-doped Sr2IrO4

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Chinese Physics B 2024年第1期33卷 696-701页

作者：岳智来甄伟立牛瑞焦珂珂朱文卡皮雳张昌锦 High Magnetic Field Laboratory Hefei Institutes of Physical ScienceChinese Academy of Sciences Science island Branch of Graduate School University of Science and Technology of China Collaborative Innovation Center of Advanced Microstructures Nanjing University

Group IV element Pb has been selected as the dopant to dope at the Sr site of Sr2IrO4. It is exciting to find that the single-phase crystal structure could be maintained with a high Pb doping level of up to x=0.3 in Sr2-xPbxIrO4. The mapping data obtained from energy-dispersive x-ray spectroscopy analyses give solid evidence that the Pb ions are uniformly distributed in the Sr2IrO4matrix. The incorporation of Pb leads to a moderate depression of the canted antiferromagnetic ordering state. The electrical conductivity could be greatly enhanced when the Pb doping content is higher than x=*** present results give a fresh material base to explore new physics in doped Sr2IrO4systems.

关键词： iridates doping conductivity magnetism

Drivers of spatial structure in thinned forests

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Forest Ecosystems 2024年第2期11卷 202-213页

作者： Zichun Wang Yaoxiang Li Guangyu Wang Zheyu Zhang Ya Chen Xiaoli Liu Rundong Peng College of Mechanical and Electrical Engineering Northeast Forestry UniversityHarbin150040China Department of Forest Resources Management University of British ColumbiaVancouverCanada

Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ***,previous research on forest management has often overlooked the importance of ***:Our objectives were to define the direction of structure-based forest ***,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning ***,the drivers of forest structural change were ***:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last *** component analysis (PCA)identified relationships among factors determining forest spatial *** structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after ***:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest ***,only moderate thinning (20%–35%trees removed) created a reasonable spatial *** dead trees were clustered,and they were hardly affected by thinning ***,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy ***:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.

关键词： Thinning Natural secondary forest Spatial structure Dynamic changes Growth factors Structural equation modeling

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