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Investigation of Power Density Amplification in Stacked Triboelectric Nanogenerators

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Energy & Environmental Materials 2024年第5期7卷 368-375页

作者： Fan Shen Qin Zhang Hengyu Guo Chen Cao Ying Gong Junlei Wang Yan Peng Zhongjie Li School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444China Department of Applied Physics Chongqing UniversityChongqing 400044China Institute of Artificial Intelligence School of Future TechnologyShanghai UniversityShanghai 200444China School of Mechanical and Power Engineering Zhengzhou UniversityZhengzhou 450000China Shanghai Artificial Intelligence Laboratory Shanghai 200232China

In engineering practice,the output performance of contact separation TENGs(CS-TENGs)increases with the increase of tribo-pair area,which includes increasing the size of single layer CS-TENGs(SCS-TENGs)or the number of units(zigzag TENGs).However,such two strategies show significant differences in output power and power *** this study,to seek a universal CS-TENG design solution,the output performance of a SCS-TENG and a zigzag TENG(Z-TENG)is systematically compared,including voltage,current,transferred charge,instantaneous power density,and charging power *** relationship between contact area and output voltages is explored,and the output voltage equation is *** experimental results reveal that SCS-TENGs yield better performance than Z-TENGs in terms of voltage,power,and power density under the same total contact area.Z-TENGs show energy loss during the transfer of mechanical energy,and such loss is aggravated by the increasing number of *** instantaneous peak power of the SCS-TENG is up to 22 times that of the Z-TENG(45 cm^(2)).Furthermore,the power density of capacitor charging of SCS-TENGs is 131%of that of Z-TENGs,which are relatively close.Z-TENG is a feasible alternative when the working space is limited.

关键词： contact separation power density triboelectric nanogenerators zigzag

Standardized Volume Power Density Boost in Frequency-Up Converted Contact-Separation Mode Triboelectric Nanogenerators

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Research 2024年第2期2023卷 691-702页

作者： Zhongjie Li Chao Yang Qin Zhang Geng Chen Jingyuan Xu Yan Peng Hengyu Guo School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444P.R.China Institute of Artificial Intelligence Shanghai UniversityShanghai 200444P.R.China National Engineering Research Center of Turbo-Generator Vibration School of Energy and EnvironmentSoutheast UniversityNanjing 210096P.R.China institute of Microstructure Technology Karlsruhe Institute of TechnologyKarlsruhe 76344Germany Shanghai Artificial Intelligence Laboratory Shanghai 200444P.R.China Department of Applied Physics Chongqing UniversityChongqing 400044P.R.China

The influence of a mechanical structure's volume increment on the volume power density (VPD) of triboelectric nanogenerators (TENGs) is often neglected when considering surface charge density and surface power density. This paper aims to address this gap by introducing a standardized VPD metric for a more comprehensive evaluation of TENG performance. The study specifically focuses on 2 frequency-up mechanisms, namely, the integration of planetary gears (PG-TENG) and the implementation of a double-cantilever structure (DC-TENG), to investigate their impact on VPD. The study reveals that the PG-TENG achieves the highest volume average power density, measuring at 0.92 W/m^(3). This value surpasses the DC-TENG by 1.26 times and the counterpart TENG by a magnitude of 69.9 times. Additionally, the PG-TENG demonstrates superior average power output. These findings introduce a new approach for enhancing TENGs by incorporating frequency-up mechanisms, and highlight the importance of VPD as a key performance metric for evaluating TENGs.

关键词： increment neglected considering

Photoluminescence of C_(60) Single Crystals

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chinese Physics Letters 1995年第5期12卷 317-320页

作者： LI Chaorong WANG Gang ZHANG Jiaming MAI Zhenhong ZHAO Tienan XU Lu XIE Sishen Institute of Physics Academia SinicaBeijing 100080 Shanghai Institute of Technical Physics Academia SinicaShanghai 200083

The photoluminescence(PL)spectra of C_(60) single crystals grown under double temperature gradient(DTG)and single temperature gradient(STG)techniques were investigated at room *** results show that the PL emission intensity increases first and then decreases with increasing illuminated power density for the C_(60) single crystals grown by both DTG and STG ***,one main peak with a shoulder peak can be clearly distinguished at low illumination,while only one main peak without the shoulder peak can be seen at high *** main peak undergoes a continuous blue shift and broadening with the increase of illuminated power *** difference of PL emission energy at the same illumination density of DTG and STG samples may correlated with the degree of both the orientational disorder of C_(60) molecule and lattice *** Laue diffraction patterns show that the DTG sample has stronger strains and poorer crystalline quality than the STG sample.

关键词： temperature. density. illumination

Advances in longitudinal studies of amnestic mild cognitive impairment and Alzheimer's disease based on multi-modal MRI techniques

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Neuroscience Bulletin 2014年第2期30卷 198-206页

作者： Zhongjie Hu Liyong Wu Jianping Jia Ying Han Department of Neurology Xuan Wu Hospital Capital Medical University Postgraduates Institute Capital Medical University Alzheimer's Disease Center Beijing Institute for Brain Disorders

Amnestic mild cognitive impairment （aMCI） is a prodromal stage of Alzheimer＇s disease （AD）, and 75%-80% of aMCI patients finally develop AD. So, early identification of patients with aMCI or AD is of great significance for prevention and intervention. According to cross-sectional studies, it is known that the hippocampus, posterior cingulate cortex, and corpus callosum are key areas in studies based on structural MRI （sMRI）, functional MRI （fMRI）, and diffusion tensor imaging （DTI） respectively. Recently, longitudinal studies using each MRI modality have demonstrated that the neuroimaging abnormalities generally involve the posterior brain regions at the very beginning and then gradually affect the anterior areas during the progression of aMCI to AD. However, it is not known whether follow-up studies based on multi-modal neuroimaging techniques （e.g., sMRI, fMRI, and DTI） can help build effective MRI models that can be directly applied to the screening and diagnosis of aMCI and AD. Thus, in the future, large-scale multi-center follow-up studies are urgently needed, not only to build an MRI diagnostic model that can be used on a single person, but also to evaluate the variability and stability of the model in the general population. In this review, we present longitudinal studies using each MRI modality separately, and then discuss the future directions in this field.

关键词： magnetic resonance imaging amnestic mild cognitive impairment Alzheimer's disease multi-modality longitudinal studies

Radiation Effect of Neutrons in a Reactor on Polyurethane

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Journal of Wuhan University of Technology(Materials science) 2010年第6期25卷 966-968页

作者：黄玮 Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics

The radiation effect of neutrons in a reactor on polyurethane was *** gases produced by irradiated samples were analyzed by gas chromatography,and the dynamic mechanical and compression properties of the samples were also *** positron annihilation lifetime of irradiated samples was measured at room temperature in *** experimental results indicate that gas chromatography is a powerful tool to quantitatively analyze the gas products from neutron-irradiated polyurethane and characterizes the chemical changes in the *** the changes in microstructure determined from the PAL correlate well with the measurements of the mechanical properties by dynamic mechanical analysis（DMA）.

关键词： neutrons in a reactor polyurethane radiation effect

Novel models for simulating maize growth based on thermal time and photothermal units: Applications under various mulching practices

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Journal of Integrative Agriculture 2023年第5期22卷 1381-1395页

作者： LIAO Zhen-qi ZHENG Jing FAN Jun-liang PEI Sheng-zhao DAI Yu-long ZHANG Fu-cang LI Zhi-jun Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of EducationNorthwest A&F UniversityYangling 712100P.R.China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041P.R.China

Maize (Zea mays L.) is one of the three major food crops and an important source of carbohydrates for maintaining food security around the *** height (H),stem diameter (SD),leaf area index (LAI) and dry matter (DM) are important growth parameters that influence maize ***,the combined effect of temperature and light on maize growth is rarely considered in crop growth *** maize growth models based on the modified logistic growth equation (Mlog) and the Mitscherlich growth equation (Mit) were proposed to simulate the H,SD,LAI and DM of maize under different mulching practices based on experimental data from 2015–*** the accumulative growing degree-days (AGDD),helio thermal units (HTU),photothermal units (PTU) or photoperiod thermal units (PPTU,first proposed here) was used as a single driving factor in the models;or AGDD was combined with either accumulative actual solar hours (ASS),accumulative photoperiod response (APR,first proposed here) or accumulative maximum possible sunshine hours (ADL) as the dual driving factors in the *** model performances were evaluated using seven statistical indicators and a global performance *** results showed that the three mulching practices significantly increased the maize growth rates and the maximum values of the growth curves compared with *** the four single factor-driven models,the overall performance of the Mlog_(PTU)Model was the best,followed by the Mlog_(AGDD)*** Mlog_(PPTU)Model was better than the Mlog_(AGDD)Model in simulating SD and *** the 10 models,the overall performance of the Mlog_(AGDD–APR)Model was the best,followed by the Mlog_(AGDD–ASS)***,the Mlog_(AGDD–APR)Model performed the best in simulating H and LAI,while the Mlog_(AGDD–ADL)and Mlog_(AGDD–ASS)models performed the best in simulating SD and DM,*** conclusion,the modified logistic growth equations with AGDD and either APR,ASS or ADL as the dual driving

关键词： thermal time accumulative growing degree-days helio thermal units photothermal units growth model

Relativistic Multichannel Theory:Doubly Excited States of Atomic Helium

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chinese Physics Letters 1998年第3期15卷 175-177页

作者： ZOU Yu FANG Quan-yu LI Jia-ming Institute of Applied Physics and Computational Mathematics Beijing 100088 Center of Atomic and Molecular sciences Department of PhysicsTsinghua UniversityBeijing 100084 Institute of Physics Chinese Academy of SciencesBeijing 100080

In the report,the recently developed relativistic multichannel theory(RMCT)is a full relativistic non-perturbative method and can be applied to the high-Z atomic ions which have given rise to some recent interests because of researches of inertial confinement fusion and x-ray *** on the RMCT,the positions and widths of doubly excited sp2n^(+),sp2n^(-),and 2pnd ^(1)P_(1) resonances are calculated,which are in agreement with the recent experimental *** sets up a sound foundation on which the RMCT should be applicable to high Z atomic ions.

关键词： relativistic excited positions

A Remark on the Mallat Pyramidal Algorithm of Wavelet Analysis

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Communications in Nonlinear science and Numerical Simulation 1997年第4期2卷 240-243页

作者： Xianbin LI &1 Houqiang LI &2 Fuquan WANG &3Jing DING 1 (Dept.of Physics,Sichuan Union University,Chengdu6 1 0 0 6 4,P.R.China) 2 (Dept.of Math.Sichuan teacher’s College,Nanchong6 370 0 2 P.R.China) 3(Dept.of Hydrology,Sichuan Union University.Chengdu6 Department of Physics Sichuan Union University Chengdu 610064 China Department of Mathematics Sichuan Teacher's College Nanchong 637002 China Department of Hydrology Sichuan Union University Chengdu 610065 China

The exact relationships between the lenthgs of scale sequences and wavelet sequences in the Mallat pyramidal algorithm for computing wavelet trans- form coefficients are obtained,and the maximum possible scale of arbi... 详细信息

关键词： wavelet transform Mallat pyramidal algorithm decomposition reconstruction

Effect of experimental warming on soil respiration under conventional tillage and no-tillage farmland in the North China Plain

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Journal of Integrative Agriculture 2017年第4期16卷 967-979页

作者： TU Chun LI Fa-dong QIAO Yun-feng ZHU Nong GU Cong-ke ZHAO Xin Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101P.R.China University of chinese Academy of science Beijing 100049P.R.China

Understanding the response of soil respiration to global warming in agro-ecosystem is crucial for simulating terrestrial carbon （C） cycle. We conducted an infrared warming experiment under conventional tillage （CT） and no-tillage （NT） farmland for winter wheat and summer maize rotation system in North China Plain （NCP）. Treatments include CT with and without warming （CTW and CTN）, NT with and without warming （NTW and NTN）. The results indicated that warming had no sig- nificant effect on soil moisture in irrigated farmland of NCP （P〉0.05）. The elevated average soil temperature of 1.1-116℃ in crop growing periods could increase annual soil CO2 emission by 10.3% in CT filed （P〉0.05）, but significantly increase it by 12.7% in NT field （P〈0.05）, respectively. The disturbances such as plowing, irrigation and precipitation resulted in the obvious soil CO2 emission peaks, which contributed 36.6-40.8% of annual soil cumulative CO2 emission. Warming would enhance these soil CO2 emission peaks; it might be associated with the warming-induced increase of autotrophic respiration and heterotrophic respiration. Compared with un-warming treatments, dissolved organic carbon （DOC） and soil microbial biomass carbon （MBC） in warming treatments were significantly increased by 11.6-23.4 and 12.9-23.6%, respectively, indicating that the positive responses of DOC and MBC to warming in both of two tillage systems. Our study highlights that climate warming may have positive effects on soil C release in NCP in association with response of labile C substrate to warming.

关键词： global warming conventional tillage no-tillage soil respiration dissolved organic carbon soil microbial biomasscarbon