检索结果-南通市图书馆

A Comparison Study of Synkinematic Illite Isolation,Quantitative X-ray Powder Diffraction,and K-Ar Dating for Direct Fault Gouge Analyses

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2023年第2期97卷 636-650页

作者： zheng Yong LI Haibing LI Junjie ZHANG Guohe SI Jialiang Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Jiangsu Donghai Continental Deep Hole Crustal Activity National Observation and Research Station DonghaiJiangsu 222300China Beijing Research Institute of Uranium Geology Beijing 100029China Military and Civilian Integration Geological Survey Center Chengdu 610000China

K-Ar dating of synkinematic illite is increasingly recognized as a central method to constrain the timing of shallow crustal *** of efficient sample preparation and quantitative identification of illite polytypes are critical to acquiring K-Ar isotope data for authigenic *** this respect,we compared the commonly used clay size separation method through centrifugation with vacuum filtration technology,showing that the former is prone to extract fractions with finer particle sizes under similar conditions,thus improving the error in the authigenic end-member ***,we demonstrated that the side-packed mounting method for X-ray diffraction analysis can significantly enhance the randomness in powder samples,thus improving the quantification accuracy compared with the front-packed and back-packed *** validity of our quantification method was confirmed by comparing Profex■modeling patterns with a suite of synthetic mixtures of known compositions,yielding an average analytical error of 3%.Dating results of these artificial mixtures and the reference materials indicated that a large range in percentages of detrital illite and a sufficient amount of age data will produce reliable results for ages of both extrapolated ***,if the range is limited,the extrapolated age close to those of datasets is still reliable.

关键词： illite polytypes fault gouge clay size separation mounting method Profex■ extrapolated K-Ar age

On Dynamic Channel Emulation in Sector MPAC for Over-the-Air Testing of Beamformed Massive MIMO Devices

在线全文

学校读者我要写书评

暂无评论

China Communications 2023年第4期20卷 41-56页

作者： Xiaochen Chen Heng Wang Weimin Wang zheng Liu Yuanan Liu China Academy of Information and Communications Technology Beijing 100191China Beijing Key Laboratory of Work Safety Intelligent Monitoring Department of Electronic EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China

In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel *** the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational *** the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading *** standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed *** simulation results show that more competent active probes are selected with the proposed method compared to the conventional ***,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical ***,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active *** satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.

关键词： beamforming channel emulation massive MIMO device multiple probe anechoic chamber(MPAC) over-the-air testing

Research and application of reanalysis data for radio astronomical site testing

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第12期20卷 279-286页

作者： Ming-Shuai Li Rui Li Na Wang Xing-Wu zheng Xinjiang Astronomical Observatory Chinese Academy of Sciences830011 UrumqiChina Key Laboratory of Radio Astronomy Chinese Academy of Sciences210034 NanjingChina School of Astronomy&Space Science Nanjing UniversityNanjing 210093China

Selecting a good site for ground-based astronomy is very important. Based on the ERA-Interim global reanalysis data, this paper studied the atmospheric conditions of the Qitai Telescope(QTT) site from the aspects of absolute humidity, mixing ratio and precipitable water vapor(PWV). Error estimations of meteorological parameters are also analyzed. These primary results show that the QTT site has obvious advantages in terms of conditions with much less atmospheric water vapor than two well-known existing sites with 100-meter-aperture radio telescopes in the world. In addition, due to the influence of atmospheric water vapor on radio observations, the atmospheric transmittance for each frequency band of the site are simulated, and the atmospheric opacity is also calculated as well as Planck radiation brightness. Based on these results, the effective observational time of different bands is further estimated.

关键词： site testing opacity radiative transfer

Distribution pattern and geochemical analysis of rare earth elements in deep-ocean sediments

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2021年第1期39卷 79-88页

作者： Jingxi LI Chengjun SUN Fenghua JIANG Fenglei GAO Yifan zheng Key Laboratory of Marine Eco-environmental Science and Technology Marine Bioresource and Environment Research CenterFirst Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory of Marine Drugs and Bioproducts Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

The content and distribution pattern of rare earth elements(REEs)in surface sediments from the Eastern and Western Pacifi c Ocean,the Northern and Southern Atlantic Ocean,and the Southwestern Indian Ocean were explored and the resources and geochemical characteristics of REEs in deep-ocean sediments from diff erent oceans were *** total REE abundances(ΣREE)in the diff erent oceans ranged as follows:Eastern Pacifi c,56.88–500.02μg/g;Western Pacifi c,290.68–439.94μg/g;Northern Atlantic,55.33–154.90μg/g;Southern Atlantic,40.83–69.30μg/g;and Southwestern Indian Ocean,20.24–64.76μg/*** corresponding LREE(La-Eu)/HREE(Gd-Lu)average values were 5.18,5.86,9.01,5.21,and 4.59,which indicated that the light REEs were all evidently enriched.δEu andδCe showed slight Eu-negative anomalies and signifi cant Ce-positive anomalies in all *** the contents of REEs in the sediments varied among the diff erent oceans,the distribution patterns of REEs were similar,and the correlation coeffi cient was greater than *** the Eastern Pacifi c sediments,ΣREE showed a signifi cantly positive correlation with Co,Cu,Zn,Mn,Mo and a weak correlation with *** the Western Pacifi c and Southern Atlantic sediments,ΣREE presented no obvious correlation and a weakly negative correlation with Co,Cu,Zn,Mn,Mo and Fe,respectively.ΣREE in the Southwestern Indian Ocean sediments positively correlated with Cu,Zn,Mn,Mo,Fe,and had a weakly negative correlation with Co.

关键词： rare earth elements(REE)geochemistry distribution pattern REE fractionation marine sediment

Mesoscopic Analysis of Deformation Heterogeneity and Recrystallization Microstructures of a Dual-Phase Steel Using a Coupled Simulation Approach

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2021年第6期34卷 777-788页

作者： Chunni Jia Gang Shen Wenxiong Chen Baojia Hu Chengwu zheng Dianzhong Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Mechanical Engineering Suzhou University of Science and TechnologySuzhou 215009China

Microstructure-based numerical modeling of the deformation heterogeneity and ferrite recrystallization in a cold-rolled dual-phase(DP)steel has been performed by using the crystal plasticity finite element method(CPFEM)coupled with a mesoscale cellular automaton(CA)*** microstructural response of subsequent primary recrystallization with the deformation heterogeneity in two-phase microstructures is *** simulations demonstrate that the deformation of multi-phase structures leads to highly strained shear bands formed in the soft ferrite matrix,which produces grain clusters in subsequent primary *** early impingement of recrystallization fronts among the clustered grains causes mode conversions in the recrystallization *** predictions regarding the grain size,microstructure morphology and kinetics can be made by comparison with the experimental *** influence of initial strains on the recrystallization is also obtained by the simulation approach.

关键词： Dual-phase steel Primary recrystallization Deformation heterogeneity Crystal plasticity finite element method Cellular automaton

Development of a biomechanical model for dynamic occlusal stress analysis

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2021年第3期13卷 292-299页

作者： zheng Duanmu Lu Liu Qi Deng Yuanyuan Ren Meiqing Wang Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument Beijing Information Science and Technology UniversityBeijingChina Department of Oral Anatomy and Physiology and TMD School of StomatologyAir Force Medical UniversityXi’anChina

The use of traditional finite element method(FEM)in occlusal stress analysis is limited due to the complexity of musculature *** present purpose was to develop a displacement boundary condition(DBC)-FEM,which evaded the muscle factor,to predict the dynamic occlusal *** geometry of the DBC-FEM was developed based on the scanned plastic casts obtained from a *** electrognathographic and video recorded jaw positional messages were adopted to analyze the dynamic occlusal *** volunteer exhibited asymmetrical lateral movements,so that the occlusal stress was further analyzed by using the parameters obtained from the right-side eccentric movement,which was 6.9 mm long,in the stress task of the left-side eccentric movement,which was 4.1 mm ***,virtual occlusion modification was performed by using the carving tool software aiming to improve the occlusal morphology at the loading sites.T-Scan Occlusal System was used as a control of the in vivo detection for the location and strength of the occlusal *** obtained from the calculation using the present developed DBC-FEM indicated that the stress distribution on the dental surface changed dynamically with the occlusal *** with the T-Scan recordings,the right-side molars always showed contacts and higher levels of *** the leftside eccentric movement trace by the right-side one enhanced the simulated stress on the right-side molars while modification of the right-side molars reduced the simulated *** present DBC-FEM offers a creative approach for pragmatic occlusion stress prediction.

关键词： stress dynamic DBC

Hybrid gray wolf optimization-cuckoo search algorithm for RFID network planning

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2021年第6期28卷 91-102页

作者： Quan Yixuan zheng Jiali Xie Xiaode Lin Zihan Luo Wencong School of Computer Electrics and InformationGuangxi UniversityNanning 530004China Guangxi Key Laboratory of Multimedia Communications and Network Technology Guangxi UniversityNanning 530004China

In recent years,with the rapid development of Internet of things(IoT)technology,radio frequency identification(RFID)technology as the core of IoT technology has been paid more and more attention,and RFID network planning(RNP)has become the primary *** with the traditional methods,meta-heuristic method is widely used in *** at the target requirements of RFID,such as fewer readers,covering more tags,reducing the interference between readers and saving costs,this paper proposes a hybrid gray wolf optimization-cuckoo search(GWO-CS)*** method uses the input representation based on random gray wolf search and evaluates the tag density and location to determine the combination performance of the reader's propagation *** with particle swarm optimization(PSO)algorithm,cuckoo search(CS)algorithm and gray wolf optimization(GWO)algorithm under the same experimental conditions,the coverage of GWO-CS is 9.306%higher than that of PSO algorithm,6.963%higher than that of CS algorithm,and 3.488%higher than that of GWO *** results show that the GWO-CS algorithm cannot only improve the global search range,but also improve the local search depth.

关键词： radio frequency identification(RFID) gray wolf optimization(GWO)algorithm cuckoo search(CS)algorithm dynamic adjustment of discovery probability directional mutation

同方期刊数据库

Propagating slow sausage waves in a sunspot observed by the New Vacuum Solar Telescope

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第8期20卷 157-162页

作者： Song Feng zheng Deng Ding Yuan Zhi Xu Xiao Yang Faculty of Information Engineering and Automation Kunming University of Science and TechnologyKunming 650500China Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518055China Yunnan Observatories Chinese Academy of SciencesKunming 650011China

A sunspot is an ideal waveguide for a variety of magnetohydrodynamic waves,which carry a significant amount of energy to the upper atmosphere and could be used as a tool to probe the magnetic and thermal structure of a *** this study,we used the New Vacuum Solar Telescope and took highresolution image sequences simultaneously in both Ti O(7058±10?A)and Hα(6562±2.5?A)*** extracted the area and total emission intensity variations of sunspot umbra and analyzed the signals with synchrosqueezing *** found that the area and emission intensity varied with both three and five minute ***,the area and intensity oscillated in phase with each other,this fact hold in both Ti O and Hα*** interpret this oscillatory signal as a propagating slow sausage *** propagation speed is estimated at about 8 km s^-*** infer that this sunspot's umbra could have temperature as low as 2800–3500 K.

关键词： Sun:sunspot Sun:oscillations magnetohydrodynamics(MHD) methods:data analysis

Cooperative Caching for Scalable Video Coding Using Value-Decomposed Dimensional Networks

在线全文

学校读者我要写书评

暂无评论

China Communications 2022年第9期19卷 146-161页

作者： Youjia Chen Yuekai Cai Haifeng zheng Jinsong Hu Jun Li Fujian Key Lab for Intelligent Processing and Wireless Transmission of Media Information College of Physics and Information EngineeringFuzhou UniversityFuzhou 350000China School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210000China

Scalable video coding(SVC)has been widely used in video-on-demand(VOD)service,to efficiently satisfy users’different video quality requirements and dynamically adjust video stream to timevariant wireless *** the 5G network structure,we consider a cooperative caching scheme inside each cluster with SVC to economically utilize the limited caching storage.A novel multi-agent deep reinforcement learning(MADRL)framework is proposed to jointly optimize the video access delay and users’satisfaction,where an aggregation node is introduced helping individual agents to achieve global observations and overall system ***,to cope with the large action space caused by the large number of videos and users,a dimension decomposition method is embedded into the neural network in each agent,which greatly reduce the computational complexity and memory cost of the reinforcement *** results show that:1)the proposed value-decomposed dimensional network(VDDN)algorithm achieves an obvious performance gain versus the traditional MADRL;2)the proposed VDDN algorithm can handle an extremely large action space and quickly converge with a low computational complexity.

关键词： cooperative caching multi-agent deep reinforcement learning scalable video coding value-decomposition network