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Analysis of Pressure Forcings for the Vertical Turbulent Fluxes in the Convective Boundary Layer at Gray Zone Resolutions

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Journal of Meteorological Research 2023年第6期37卷 841-854页

作者： Yahua WANG Xiaoping CHENG Jianfang FEI Bowen zhou College of Meteorology and Oceanography National University of Defense TechnologyChangsha410005China Key Laboratory of Electro-Optical Countermeasures Test and Evaluation Technology Luoyang471000China Key Laboratory for Mesoscale Severe Weather Ministry of EducationSchool of Atmospheric SciencesNanjing UniversityNanjing210000China

At kilometer and sub-kilometer resolutions,known as the numerical gray zone for boundary layer turbulence,the atmospheric boundary layer turbulence becomes partially resolved and partially subgrid-scale(SGS) in a numerical model,thus requiring scale-adaptive turbulence *** schemes are often built by modifying the existing parameterizations,either the planetary boundary layer(PBL) schemes or the large-eddy simulation(LES) closures,to produce the right SGS turbulent fluxes at gray zone ***,the underlying forcings responsible for the changes in the vertical turbulent fluxes are largely ignored in these *** study follows the original approach of Wyngaard(2004) and analyzes the turbulent buoyancy and momentum flux budgets,to gain a better understanding of the variations of flux forcings at gray zone *** investigation focuses on the pressure covariance term,which is one of the most dominant terms in the budget *** using the coarse-grained LES of a dry convective boundary layer(CBL) case as reference,two widely-used pressure covariance models are evaluated and optimized across the gray zone resolution *** optimized linear model is further evaluated a priori against another dry CBL case with a different bulk stability,and a shallow-cumulus-topped boundary layer *** model applies well to both cases,and notably shows good performance for the cloud *** on the analysis of the flux forcings and the optimized pressure model,a scale-adaptive turbulence model for the gray zone is derived from the steady-state flux budgets.

关键词： convective boundary layer gray zone flux budget pressure covariance turbulence parameterization

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Contributions of annual and semiannual tidal constituents to chart datum in the China seas and adjacent waters

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Acta Oceanologica Sinica 2023年第10期42卷 127-136页

作者： Yikai Feng Yanguang Fu Long Yang Dongxu zhou First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China

Global uniform chart datum(CD)surface construction is the basic upon which to realize various vertical datums transformation,and is of great importance for geospatial data expression under the same vertical ***,the CD level is computed by developing the function between tidal constituents’harmonic constants and time,i.e.,the lowest astronomical tide is taken as the lowest predicted tide level by adopting the major constituents over a 19-a *** CD surface prescribed in China is the theoretical lowest tide(TLT)and is calculated using 13 tidal constituents,i.e.,short-period(Q_(1),O_(1),P_(1),K_(1),N_(2),M_(2),S_(2),K_(2),M_(4),MS_(4)and M_(6))and long-period(Sa and Ssa)tidal *** the accuracy in determining short-period tidal constituents has improved gradually,the long-period tide has not been studied thoroughly owing to nonstationary and temporal *** studies have intended to evaluate the effect of Sa and Ssa tides in the determination of the TLT level for the purpose of determining a more accurate CD surface for the China seas and adjacent ***,the parameters of long-period tidal correction and long-period tidal correction rate were treated as the effect of both Sa and Ssa on the TLT,and the TOPEX/Poseidon and Jason series satellite altimetry data ranged from October 1992 to April 2022 were adopted to analyze the contribution of long-period tidal *** showed that the average long-period correction value is 10.10 cm(range from 8.57 cm to 14.98 cm),and that the average long-period tidal contribution rate is 14.56%(range from 9.09%to 23.97%)in the China seas and adjacent ***,data from 82 tide gauge station with at least a 1-a record of hourly observations were compared with satellite-derived *** concluded that the long-period tidal contribution should not be neglected in TLT ***,to reduce tidal datum uncertainty,accurate extraction of long-period tidal constit

关键词： tidal datum chart datum long-period tidal constituent lowest normal low water China seas and adjacent waters

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Capacity and Spatial Correlation Measurements of Compact MIMO Antennas

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China Communications 2021年第6期18卷 137-145页

作者： Dazhi Piao Meng Wang Jie Zuo Hao zhou School of Information and Communication Engineering Communication University of ChinaBeijing 100024China

The dual-port compact multiple-input multiple-output(MIMO)dipole antennas with close spacing d of 0.5λand 0.3λare designed,and some electromagnetic band gap(EBG)structures are inserted between them to reduce mutual *** MIMO antennas with d=0.5λand 0.3λ,and with different mutual couplings are fabricated and measured,the channel capacity and correlation coefficient(CC)are analyzed and compared in a rich multipath reverberation chamber(RC),an office and a conference *** show that if d is reduced from 0.5λto 0.3λ,in the RCs,channel capacities of all the antennas are very close to that of the *** channel,although the average CCs are increased from 0.168 in the nonlossy RC to 0.269 in the lossy *** the office and conference rooms,compared with the RC,the average capacities of those antennas get a slight reduction,however,in most cases,the capacity of d=0.5λis larger than that of d=0.3λ,and the antennas with EBG have a larger capacity compared with the antennas without EBG,with a corresponding reduction of CC.A non-line-of-sight(NLOS)scenario of through-the-wall is also investigated.

关键词： compact MIMO antenna channel capacity spatial correlation measurement

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Almost Periodic Solutions by the Harmonic Balance Method

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Acta Mathematicae Applicatae Sinica 2022年第4期38卷 943-954页

作者： Ji-feng CHU Zuo-huan ZHENG Zhe zhou Department of Mathematics Shanghai Normal UniversityShanghai 200234China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China College of Mathematics and Statistics Hainan Normal UniversityHaikou 571158China

We consider non-autonomous ordinary differential equations in two *** is the one-dimensional case that admits a condition of hyperbolicity,and the other one is the higher-dimensional case that admits an exponential *** differential equations of this kind,we give a rigorous treatment of the Harmonic Balance Method to look for almost periodic solutions.

关键词： almost periodic solution Harmonic balance method exponential dichotomy

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Impact of food to microorganism ratio and alcohol ethoxylate dosage on methane production in treatment of low-strength wastewater by a submerged anaerobic membrane bioreactor

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Frontiers of Environmental Science & Engineering 2017年第6期11卷 47-57页

作者： Yulun Nie Xike Tian Zhaoxin zhou Yu-You Li Faculty of Material Science and Chemistry China University of Geosciences Wuhan 430074 China Department of Civil and Environmental Engineering Graduate School of Engineering Tohoku University 6-6-06 Aza-Aoba Aramaki Aoba-ku Sendai Miyagi 980-8579 Japan

The effects of food to microorganism （FIM） ratio and alcohol ethoxylate （AE） dosage on the methane production potential were investigated in treatment of low-strength wastewater by a submerged anaerobic membrane bioreactor （SAnMBR）. The fate of AE and its acute and/or chronic impact on the anaerobic microbes were also analyzed. The results indicated that AE had an inhibitory effect to methane production potential （lag-time depends on the AE dosage） and the negative effect attenuated subsequently and methane production could recover at FIM ratio of 0.088-0.357. VFA measurement proved that AE was degraded into small molecular organic acids and then converted into methane at lower FIM ratio （FIM 〈 0.158）. After long-term acclimation, anaerobic microbe could cope with the stress of AE by producing more EPS （extracellular polymeric substances） and SMP （soluble microbial products） due to its self-protection behavior and then enhance its tolerance ability. However, the methane production potential was considerably decreased when AE was present in wastewater at a higher FIM ratio of 1.054. Higher AE amount and FIM ratio may destroy the cell structure of microbe, which lead to the decrease of methane production activity of sludge and methane production potential.

关键词： Anaerobic membrane bioreactor AnMBR F/M ratio Surfactant Wastewater Methane production Influence

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Dynamic interactions of an integrated vehicle–electromagnetic energy harvester–tire system subject to uneven road excitations

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Acta Mechanica Sinica 2017年第2期33卷 440-456页

作者： Jing Tang Xing Zhe Sun Sulian zhou Mingyi Tan Fluid Structure Interactions Group FEEUniversity of Southampton College of Shipbuilding Engineering Harbin Engineering University

An investigation is undertaken of an integrated mechanical-electromagnetic coupling system consisting of a rigid vehicle with heave, roll, and pitch motions, four electromagnetic energy harvesters and four tires subject to uneven road excitations in order to improve the passengers' riding comfort and harvest the lost engine energy due to uneven roads. Following the derived mathematical formulations and the proposed solution approaches, the numerical simulations of this interaction system subject to a continuous sinusoidal road excitation and a single ramp impact are completed. The simulation results are presented as the dynamic response curves in the forms of the frequency spectrum and the time history, which reveals the complex interaction characteristics of the system for vibration reductions and energy harvesting performance. It has addressed the coupling effects on the dynamic characteristics of the integrated system caused by: (1) the natural modes and frequencies of the vehicle; (2) the vehicle rolling and pitching motions; (3) different road excitations on four wheels; (4) the time delay of a road ramp to impact both the front and rear wheels, etc., which cannot be tackled by an often used quarter vehicle model. The guidelines for engineering applications are given. The developed coupling model and the revealed concept provide a means with analysis idea to investigate the details of four energy harvester motions for electromagnetic suspension designs in order to replace the current passive vehicle isolators and to harvest the lost engine energy. Potential further research directions are suggested for readers to consider in the future.

关键词： Vibration-energy-harvesters Electromagnetic suspensions Mechanical electromagnetic interactions Vehicle dynamics Vibration isolations

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Is the East Asian flora ancient or not?

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National Science Review 2018年第6期5卷 920-932页

作者： Yong-Sheng Chen Tao Deng Zhuo zhou Hang Sun Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of Sciences College of Life Science Northeast Agricultural University University of Chinese Academy of Sciences

The East Asian flora(EAF) is a key biodiversity hotspot for understanding the origin and evolution of Northern Hemisphere floras, but there is an ongoing debate on whether it is a museum or a cradle for seed plants. Within the EAF, two main floras, the Sino-Himalayan Flora(mainly the Rhododendron Flora) and the Sino-Japanese Flora(mainly the Metasequoia Flora), have been recognized. Previous studies suggested that the EAF is ancient and the Metasequoia Flora is older than the Rhododendron Flora. To test this hypothesis, we synthesized molecular as well as fossil data on seed plants, focusing on the biogeographical origins and historical evolution of the EAF. We compared the ages of its two constituent floras, and examined the impact of the Asian monsoon and other environmental changes on the development of EAF through meta-analysis. Our results suggest that the EAF might be relatively young, with most of its clades originating since the Miocene. The Rhododendron Flora and the Metasequoia Flora are probably of a similar age. The formation and development of the Asian monsoon might have been the main factors that have driven the evolution of EAF. In the Rhododendron Flora, the north-south mountain chains increased the concentration of species and reduced extinction, and the barriers between the east and west have resulted in species differentiation, which triggered it to become a diversity center. The EAF appears to have multiple biogeographical origins, having closely affiliated not only with other floras in the Northern Hemisphere, but also with Gondwanan floras.

关键词： Asian monsoon East Asian Flora Metasequoia Flora Rhododendron Flora temporal and spatial evolution

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Micro defects formation and dynamic response analysis of steel plate of quasi-cracking area subjected to explosive load

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Defence Technology（防务技术） 2024年第1期31卷 580-593页

作者： Zheng-qing zhou Ze-chen Du Xiao Wang Hui-ling Jiang Qiang zhou Yu-long Zhang Yu-zhe Liu Pei-ze Zhang Research Institute of Macro-Safety Science University of Science and TechnologyBeijing100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China School of Mechanical Engineering Nantong UniversityNantong226019China China North Industry Advanced Technology Generalization Institute Beijing100089China China Academy of Ordnance Science China

As the protective component,steel plate had attracted extensive attention because of frequently threats of explosive *** this paper,the evolution of microstructure and the mechanism of damage in the quasi-cracking area of steel plate subjected to explosive load were discussed and the relationships between micro defects and dynamic mechanical response were *** the explosion experiment,five observation points were selected equidistant from the quasi-cracking area of the section of the steel plate along the thickness direction,and the characteristics of micro defects at the observation points were analyzed by optical microscope(OM),scanning electron microscope(SEM) and electron backscattered diffraction(EBSD).The observation result shows that many slip bands(SBs) appeared,and the grain orientation changed obviously in the steel plate,the two were the main damage types of micro *** addition,cracks,peeling pits,grooves and other lager micro defects were appeared in the lower area of the *** stress parameters of the observation points were obtained through an effective numerical *** mechanism of damage generation and crack propagation in the quasicracking area were clarified by comparing the specific impulse of each observation point with the corresponding micro *** result shows that the generation and expansion of micro defects are related to the stress area(*** upper compression area,the neutral plane area,and the lower tension area).The micro defects gather and expand at the grain boundary,and will become macroscopic damage under the continuous action of tensile ***,the micro defects at the midpoint of the section of the steel plate in the direction away from the explosion center(*** horizontal direction) were also *** was found that the specific impulse at these positions were much smaller than that in the thickness direction,the micro defects were only SBs and a few micro cracks,and the those decrea

关键词： Explosive load Quasi-cracking area Micro defects Steel plate Dynamic response Numerical simulation

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Analysis of a rainwater harvesting system for domestic water supply in zhoushan,China

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 342-348页

作者： Yong-chao zhou Wei-yun SHAO Tu-qiao ZHANG Institute of Municipal Engineering Zhejiang University Hangzhou 310058 China

The domestic rainwater harvesting system (DRHS) is an important freshwater source for zhoushan,China to meet water demands. A computer model has been generated to analyze the performance of the DRHS with different ratios of D/(AR) (water demand/average annual collected runoff) and S/(AR) (storage capacity/average annual collected runoff). The performance of the DRHS was analyzed by means of the model simulation,which is described by its water shortage rate (WSR) and water loss rate (WLR). Using the data,a set of dimensionless design calculation chart is introduced. When the water demand and requirement of the design are known,the established chart can be used to easily determine the storage capacity and catchment (roof and other surface) area required to achieve a desired performance level.

关键词： Domestic rainwater harvesting system (DRHS) Performance Simulation zhoushan

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Symmetric Periodic Noncollision Solutions for N-Body-Type Problems

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Acta Mathematica Sinica,English Series 1995年第1期11卷 37-43页

作者： Zhang Shiqing zhou Qing Department of Applied Mathematics Chongqing University Chongqing People's Republic of China Department of Mathematics East China Normal University Shanghai People's Republic of China

Using the calculus of variations in the large,especially computing the category of the symmetric configuration space of symmetric N-body-type problems,we prove the existence of infinitely many symmetric noncollision periodic solutions about the symmetric and nonau- tonomous N-body-type problems under the assumptions that the symmetric potentials satisfy the strong force condition of Gordon.

关键词： Math Symmetric Periodic Noncollision Solutions for N-Body-Type Problems lim body

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