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Numerical simulation and inversion of offshore area depth based on x-band microwave radar

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Acta Oceanologica Sinica 2015年第3期34卷 108-114页

作者： WANG Li WU Xiongbin PI Xiaoshan MA Ketao LIU Jianfei tian Yun Radio Oceanography Laboratory School of Electronic Information Wuhan University

A detection method of offshore area depth utilizing the x-band microwave radar is proposed. The method is based on the sea clutter imaging mechanism of microwave radar, and combined with dispersion equation of the liner wave theorem and least square method （LSM）, consequently get the inversion results of water depth in the detected region. The wave monitoring system OSMAR-X exploited by the Ocean State Laborato-ry, Wuhan University, based on a microwave radar has proven to be a powerful tool to monitor ocean waves in time and space. Numerical simulation and inversion of offshore area depth are carried out here; since JONSWAP model can give description of stormy waves in different growth phase, it is suitable for simulation. Besides, some results from measured data detected by OSMAR-X x-band radar located at Longhai of Fujian Province, China, validates this method. The tendency of the average water depths inferred from the radar images is in good agreement with the tide level detected by Xiamen tide station. These promising results suggest the possibility of using OSMAR-X to monitor operationally morphodynamics in coastal zones. This method can be applied to both shore-based and shipborne x-band microwave radar.

关键词： microwave radar offshore area depth JONSWAP model numerical simulation liner wave theorem

Virtual simulation analysis and verification of seed-filling mechanism for dipper hill-drop precision direct rice seeder

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International Journal of Agricultural and Biological Engineering 2017年第6期10卷 77-85页

作者： Wang Jinwu Zhou Wenqi tian Liquan Li Shuwei Zhang Zhao College of Engineering Northeast Agricultural UniversityHarbin 150030China College of Mechanical and Electrical Engineering Jinhua PolytechnicJinhua 321017China

In order to improve the seeder’seed-filling ability of the dipper hill-drop precision direct rice seeder,and to meet the mechanization requirement of high speed operation,the self-designed seeder was taken as the objective to explore its seed-filling mechanism and the movement status of rice seed in seed box from the perspective of *** force models of seed-filling process by dipper were established,and the influential regularity of its rotation speed to compressive resistance of seed population was analyzed as *** image processing Module-Clipping of discrete element simulation software EDEM was used in the virtual simulation analysis for the process of the seed filling into the dipper,and the velocity relation curve and the force changing curve between rotation speed and seeds were *** to the virtual experiment,the composite filling force of seeds,*** qualified rate on filled rice seed amounts was the largest when rotation speed was at 40 r/*** performance test bed of seeder was used to verify the simulation results,in which the qualified rate on scooped rice seed amounts was taken as the index,and six rotation speeds of seed-filling dipper were also selected for analysis of seed-filling ability of the *** results are as follows:with the increase of working speed,the qualified rate on filled rice seed amounts fluctuated with a trend of cosine curve,the largest value was 94.16%occurred when the rotation speed of seed-filling dipper was at 40 r/*** variation trend of simulation value was approximately consistent with that of verification *** study can provide a reference for the research and development of mechanical seeder.

关键词： precision direct rice seeding rice seed dipper seeder seed-filling performance EDEM force model

A Bilinear Bcklund Transformation and N-Soliton-Like Solution of Three Coupled Higher-Order Nonlinear Schrdinger Equations with Symbolic Computation

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Communications in Theoretical Physics 2008年第9期50卷 689-695页

作者： ZHU Hong-Wu tian Bo MENG Xiang-Hua LI Juan XU Tao School of Science P.O. Box 122 Beijing University of Posts and Telecommunications Beijing 100876 China Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China Hunan Meteorological Observatory Changsha 410007 China

A bilinear Baecklund transformation is presented for the three coupled higher-order nonlinear Schroedinger equations with the inclusion of the group velocity dispersion, third-order dispersion and Kerr-law nonlinearity, which can describe the dynamics of alpha helical proteins in living systems as well as the propagation of ultrashort pulses in wavelength-division multiplexed system. Starting from the Baecklund transformation, the analytical soliton solution is obtained from a trivial solution. Simultaneously, the N-soliton-like solution in double Wronskian form is constructed, and the corresponding proof is also given via the Wronskian technique. The results obtained from this paper might be valuable in studying the transfer of energy in biophysics and the transmission of light pulses in optical communication systems.

关键词： coupled higher-order nonlinear Schroedinger equations Baecklund transformation soliton solution Wronskian technique symbolic computation

Preparation and Properties of Eco-Friendly Aerated Concrete Utilizing High-Volume Fly Ash with MgO and CaO Activators

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Journal of Renewable Materials 2022年第12期10卷 3335-3350页

作者： Xiaoling Qu Xingshuo Yang Siqi li Changan tian Zaibo Li Zhiguang Zhao School of Chemistry and Civil Engineering Shaoguan University Shaoguan512005China

The associated MgO in limestone is believed to affect the volume stability of cementitious materials at room tem-perature,which limits the utilization of low grade *** this study,MgO was used as an alkali activator instead of partial CaO to prepare the aerated concrete under hydrother mal *** expansion process was studied to evaluate the influence of the raw materials on the gas forming stability of the *** pore structure(porosity,pore size and its distribution)was analyzed by the image *** physic mechanical properties(density,strength,thermal properties)of concrete with the addition of MgO were comprehensively ***,the mineral compositions and morphology of the hydration products were analyzed to demonstrate the infuence mechanism of MgO on the mechanical *** results show that the final expansion rate of the slurry decreases with MgO content.A reasonable MgO content,ie,MgO/(MgO+CaO)<20%,con-tributes to improve the compressive strength,attributing to an increased reaction rate to C-S-H gel and *** addition of MgO causes the thermal conductivity and specific heat to *** pore structure is mainly related to the amount of air entraining *** study has a significance for the further utilization of magnesium-rich carbonates in the autoclaved building products.

关键词： Fly ash aerated concrete,strength thermal properties pore structure

The Memory Orchestra:Contribution of Astrocytes

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Neuroscience Bulletin 2023年第3期39卷 409-424页

作者： Yi-Hua Chen Shi-Yang Jin Jian-Ming Yang tian-Ming Gao State Key Laboratory of Organ Failure Research Key Laboratory of Mental Health of the Ministry of EducationGuangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired IntelligenceGuangdong Province Key Laboratory of Psychiatric DisordersDepartment of NeurobiologySchool of Basic Medical SciencesSouthern Medical UniversityGuangzhou 510515China

For decades,memory research has centered on the role of neurons,which do not function in ***,astrocytes play important roles in regulating neuronal recruitment and function at the local and network levels,forming the basis for information processing as well as memory formation and *** this review,we discuss the role of astrocytes in memory functions and their cellular underpinnings at multiple time *** summarize important breakthroughs and controversies in the field as well as potential avenues to further illuminate the role of astrocytes in memory processes.

关键词： Astrocytes Learning and memory GPCR Calcium signal Plasticity

Modeling the Warming Impact of Urban Land Expansion on Hot Weather Using the Weather Research and Forecasting Model: A Case Study of Beijing, China

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Advances in Atmospheric Sciences 2018年第6期35卷 723-736页

作者： Xiaojuan LIU Guangjin tian Jinming FENG Bingran MA Jun WANG Lingqiang KONG State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University School of Government Beijing Normal University CAS Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences

The impacts of three periods of urban land expansion during 1990–2010 on near-surface air temperature in summer in Beijing were simulated in this study, and then the interrelation between heat waves and urban warming was assessed. We ran the sensitivity tests using the mesoscale Weather Research and Forecasting model coupled with a single urban canopy model,as well as high-resolution land cover data. The warming area expanded approximately at the same scale as the urban land expansion. The average regional warming induced by urban expansion increased but the warming speed declined slightly during 2000–2010. The smallest warming occurred at noon and then increased gradually in the afternoon before peaking at around 2000 LST—the time of sunset. In the daytime, urban warming was primarily caused by the decrease in latent heat flux at the urban surface. Urbanization led to more ground heat flux during the day and then more release at night, which resulted in nocturnal warming. Urban warming at night was higher than that in the day, although the nighttime increment in sensible heat flux was smaller. This was because the shallower planetary boundary layer at night reduced the release efficiency of near-surface heat. The simulated results also suggested that heat waves or high temperature weather enhanced urban warming intensity at night. Heat waves caused more heat to be stored in the surface during the day, greater heat released at night, and thus higher nighttime warming. Our results demonstrate a positive feedback effect between urban warming and heat waves in urban areas.

关键词： heat wave numerical simulation urbanization surface heat flux WRF UCM

Diversity and conservation of Chinese wild begonias

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Plant Diversity 2018年第3期40卷 75-90页

作者： Daike tian Yan Xiao Yi Tong Naifeng Fu Qingqing Liu Chun Li Shanghai Chenshan Plant Science Research Center of Chinese Academy of Sciences Shanghai Chenshan Botanical Garden Shanghai 201602 China Shanghai Key Laboratory of Plant Functional Genomics and Resources Shanghai 201602 China Lushan Forestry Bureau Ya'an 625600 Sichuan China

Begonia, one of the most diverse plant taxa and the fifth or sixth largest angiosperm genus, consists of over1800 accepted species. The number of species recognized within this genus has greatly increased over the past 20 years, rising from 80 to 200 species in China alone. Based on recent field surveys, the number of begonia species in China is predicted to be between 250 and 300. Given the large number of begonia species that still remain to be described, further taxonomical work is urgently required. This is especially true for Chinese Begonia, in which there is a huge diversity of habitat, habit, plant size, leaf type, flower and fruit morphology, and most species are narrowly distributed in isolated habitats that are subject to negative disturbances from climate change, as well as agricultural and industrial activities. Although the conservation status for the majority of species has been evaluated using the standards of the International Union for Conservation of Nature, the results don't represent the truth in many species, and also about11.5% of which are data-absent. In addition, illegal collection and over-harvesting of wild begonias for ornamental or medicinal use has increased due to the rapid development of internet commerce. Far more often than predicted, these species should be categorized as rare and endangered and require immediate protection. Ex situ conservation of Chinese begonias started in 1995 and over 60% of the total species have been so far introduced into cultivation by several major botanical gardens in China. However, only few research institutions, limited funds and human resources have been involved in Begonia conservation;moreover, no project has conducted reintroduction. Therefore, more conservation-based work remains to be done. Improved conservation of Chinese begonias in the future depends on further field survey, an improved understanding of population diversity, and integrative approaches, including in situ and ex situ conservat

关键词： Begonia Germplasm Diversity Conservation Taxonomic status China

Propulsion Principles of Water Striders in Sculling Forward through Shadow Method

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Journal of Bionic Engineering 2018年第3期15卷 516-525页

作者： Hongyu Lu Yelong Zheng Wei Yin Dashuai Tao Noshir Pesika Yonggang Meng Yu tian State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Precision Measuring Technology and Instrument Tianjin University Tianjin 300072 China Lubrication and Friction Testing Center Tianjin Research Institute for Advanced Equipment Tsinghua University Tianjin 300300 China Chemical & Biomolecular Engineering Department Tulane University New Orleans 70112 USA

Semi-aquatic arthropods skate on water surfaces with synergetic actions of their legs. The sculling forward locomotion of water striders was observed and analyzed in situ to understand and reproduce the abovementioned feature. The bright-edged elliptical shadows of the six legs of a water strider were recorded to derive the supporting force distributions on legs. The propulsion principles of water striders were quantitatively disclosed. A typical sculling forward process was accomplished within approximately 0.15 s. Water striders lifted their heads slightly and supported their weight mainly by the two driving legs to increase the propulsion force and reduce the water resistance during the process. The normalized thrust-area ratio （defined as the ratio of the propulsion force to the projected area） was usually lower than 0.4 after sculling for approximately 0.08 s. The entire normal supporting force remained nearly constant during a stroke to reduce the mass center fluctuation in the normal direction. In addition, water striders could easily control the locomotion direction and speed through the light swinging of the two hind legs as rudders. These sculling principles might inspire sophisticated biomimetic wa- ter-walking robots with high propulsion efficiency in the future.

关键词： shadow method water strider sculling forward locomotion propulsion principle

New technology for recycling materials from oily cold rolling mill sludge

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1141-1147页

作者： Bo Liu Shen-gen Zhang Jian-jun tian De-an Pan Ling Meng Yang Liu Institute for Advanced Materials and Technology University of Science and Technology Beijing

Oily cold rolling mill （CRM） sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of ＂hydrometallurgical treatment ＋ hydrothermal synthesis＂ was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide （MIO） pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints （ISO 10601-2007）. This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.

关键词： cold rolling mills sludge disposal hydrometallurgy hydrothermal synthesis recycling, waste utilization