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113篇 您的检索式:作者名="Weixing Zhang"
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1Modeling the global ionospheric total electron content with empirical orthogonal function analysis显示文摘In the present work we model the global ionospheric total electron content (TEC) with the analysis of empirical orthogonal functions (EOF). The obtained statistical eigen modes, which makeup the modeled TEC, consist of two factors: the eigen vectors mapping TEC patterns at latitude and longitude (or local time LT), and the corresponding coefficients displaying the TEC variations in different time scales, i.e., the solar cycle, the yearly (annual and semiannual) and the diurnal universal time variations. It is found that the EOF analysis can separate the TEC variations into chief processes and the first two modes illustrate the most of the ionospheric climate properties. The first mode contains both the semiannual component which shows the semiannual ionospheric anomaly and the annual component which shows the annual or non-seasonal ionospheric anomaly. The second mode contains mainly the annual component and shows the normal seasonal ionospheric variation at most latitudes and local time sectors. The annual component in the second mode also manifests seasonal anomaly of the ionosphere at higher mid-latitudes around noontime. It is concluded that the EOF analysis, as a statistical eigen mode method, is resultful in analyzing the ionospheric climatology hence can be used to construct the empirical model for the ionospheric climatology.WAN WeiXing DING Feng REN ZhiPeng ZHANG ManLian LIU LiBo NING BaiQi 2012Science China(Technological Sciences)2012,55,5:15
2Grid Forming Converters in Renewable Energy Sources Dominated Power Grid:Control Strategy,Stability,Application,and Challenges显示文摘The renewable energy sources(RESs)dominated power grid is an envisaged infrastructure of the future power system,where the commonly used grid following(GFL)control for grid-tied converters suffers from lacking grid support capability,low stability,etc.Recently,emerging grid forming(GFM)control methods have been proposed to improve the dynamic performance and stability of grid-tied converters.This paper reviews existing GFM control methods for the grid-tied converters and compares them in terms of control structure,grid support capability,fault current limiting,and stability.Considering the impact of fault current limiting strategies,a comprehensive transient stability analysis is provided.In addition,this paper explores the typical applications of GFM converters,such as AC microgrid and offshore wind farm high-voltage direct current(OWF-HVDC)integration systems.Finally,the challenges to the GFM converters in future applications are discussed.Haobo Zhang Wang Xiang Weixing Lin Jinyu Wen 2021Journal of Modern Power Systems and Clean Energy2021,9,6:15
3A review of road extraction from remote sensing images显示文摘As a significant role for traffic management,city planning,road monitoring,GPS navigation and map updating,the technology of road extraction from a remote sensing(RS) image has been a hot research topic in recent years.In this paper,after analyzing different road features and road models,the road extraction methods were classified into the classification-based methods,knowledge-based methods,mathematical morphology,active contour model,and dynamic programming.Firstly,the road features,road model,existing difficulties and interference factors for road extraction were analyzed.Secondly,the principle of road extraction,the advantages and disadvantages of various methods and research achievements were briefly highlighted.Then,the comparisons of the different road extraction algorithms were performed,including road features,test samples and shortcomings.Finally,the research results in recent years were summarized emphatically.It is obvious that only using one kind of road features is hard to get an excellent extraction effect.Hence,in order to get good results,the road extraction should combine multiple methods according to the real applications.In the future,how to realize the complete road extraction from a RS image is still an essential but challenging and important research topic.Weixing Wang Nan Yang Yi Zhang Fengping Wang Ting Cao Patrik Eklund 2016Journal of Traffic and Transportation Engineering(English Edition)2016,3,3:9
4Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool显示文摘Chang’E-4 landed in the South Pole-Aitken(SPA)basin,providing a unique chance to probe the composition of the lunar interior.Its landing site is located on ejecta strips in Von Karm´an crater that´possibly originate from the neighboring Finsen crater.A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission operations.In situ spectra of the regolith have peak band positions at 1 and 2μm,similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper,which confirms that the regolith’s composition of the landing area is mostly similar to that of Finsen ejecta.The rock spectrum shows similar band peak positions,but stronger absorptions,suggesting relatively fresh exposure.The rock may consist of 38.1±5.4%low-Ca pyroxene,13.9±5.1%olivine and 48.0±3.1%plagioclase,referred to as olivine-norite.The plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle,but representative of the lunar lower crust.Alternatively,the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle materials.This scenario is consistent with fast-cooling thermal conditions of a shallow melt pool,indicated by the fine to medium-sized texture(<3 mm)of the rock and the SPA-impact melting model[Icarus 2012;220:730–43].Honglei Lin Zhiping He Wei Yang Yangting Lin Rui Xu Chi Zhang Meng-Hua Zhu Rui Chang Jinhai Zhang Chunlai Li Hongyu Lin Yang Liu Sheng Gou Yong Wei Sen Hu Changbin Xue Jianfeng Yang Jie Zhong Xiaohui Fu Weixing Wan Yongliao Zou 2020National Science Review2020,7,5:9
5Joint calibration algorithm for gain-phase and mutual coupling errors in uniform linear array显示文摘The effect of gain-phase perturbations and mutual coupling significantly degrades the performance of digital array radar(DAR). This paper investigates array calibration problems in the scenario where the true locations of auxiliary sources deviate from nominal values but the angle intervals are known. A practical algorithm is proposed to jointly calibrate gain-phase errors and mutual coupling errors. Firstly, a simplified model of the distortion matrix is developed based on its special structure in uniform linear array(ULA). Then the model is employed to derive the precise locations of the auxiliary sources by one-dimension search. Finally, the least-squares estimation of the distortion matrix is obtained. The algorithm has the potential of achieving considerable improvement in calibration accuracy due to the reduction of unknown parameters. In addition,the algorithm is feasible for practical applications, since it requires only one auxiliary source with the help of rotation platforms. Simulation results demonstrate the validity, robustness and high performance of the proposed algorithm. Experiments were carried out using an S-band DAR test-bed.The results of measured data show that the proposed algorithm is practical and effective in application.Li Weixing Lin Jianzhi Zhang Yue Chen Zengping 2016Chinese Journal of Aeronautics2016,29,4:9
6Effects of afforestation on soil carbon turnover in China's subtropical region显示文摘Afforestation in China's subtropics plays an important role in sequestering CO2 from the atmosphere and in storage of soil carbon (C). Compared with natural forests,plantation forests have lower soil organic carbon (SOC) content and great potential to store more C. To better evaluate the effects of afforestation on soil C turnover,we investigated SOC and its stable C isotope (δ13C) composition in three planted forests at Qianyanzhou Ecological Experimental Station in southern China. Litter and soil samples were collected and analyzed for total organic C,δ13C and total nitrogen. Similarly to the vertical distribution of SOC in natural forests,SOC concentrations decrease exponentially with depth. The land cover type (grassland) before plantation had a significant influence on the vertical distribution of SOC. The SOC ?13C composition of the upper soil layer of two plantation forests has been mainly affected by the grass biomass 13C composition. Soil profiles with a change in photosynthetic pathway had a more complex 13C isotope composition distribution. During the 20 years after plantation establishment,the soil organic matter sources influenced both the δ13C distribution with depth,and C replacement. The upper soil layer SOC turnover in masson pine (a mean 34% of replacement in the 10 cm after 20 years) was more than twice as fast as that of slash pine (16% of replacement) under subtropical conditions. The results demonstrate that masson pine and slash pine plantations cannot rapidly sequester SOC into long-term storage pools in subtropical China.WANG Shaoqiang LIU Jiyuan ZHANG Cheng YI Chuixiang WU Weixing 2011Journal of Geographical Sciences2011,21,1:8
7Power generation and heat sink improvement characteristics of recooling cycle for thermal cracked hydrocarbon fueled scramjet显示文摘In order to further investigate how much fuel heat sink could be increased and how much power generation could be obtained by using recooling cycle for a regeneratively cooled scramjet,the energy conversion from heat to electricity and the fuel heat sink increase in recooling cycle are experimentally investigated for fuel conversion rate and components of gas cracked fuel products at different fuel temperatures.The results indicate that the total fuel heat sink(i.e.,physical+chemical+recooling) of a recooling cycle is obviously higher than the heat sink of fuel itself,and the maximum heat sink increment is as high as 0.4 MJ/kg throughout the recooling cycle.Furthermore,the cracked fuel mixture has a significant capacity of doing work.The thermodynamic power generation scheme,which adopts the cracked fuel gas mixture as the working fluid,is a potential power generation cycle,and the maximum specific power generation is about 500 kW/kg.Turbine-pump scheme using cracked fuel gas mixture is also a potential fuel feeding cycle.BAO Wen QIN Jiang ZHOU WeiXing ZHANG Duo YU DaRen 2011Science China(Technological Sciences)2011,54,4:6
8SIRT1 rs3758391 and Major Depressive Disorder: New Data and Meta-Analysis显示文摘Dear Editor,It is known that genetic factors play important roles in the pathophysiology of major depressive disorder (MDD).However, its genetic mechanism is still unknown.Recently, the CONVERGE consortium performed wholegenome sequencing in a homogenous Chinese sample(5303 MDD patients and 5337 controls) and one locus near the silent mating type information regulation 2 homologWei Tang Yan Chen Xinyu Fang Yewei Wang Weixing Fan Chen Zhang 2018Neuroscience Bulletin2018,34,5:5
9Microelectronics-embedded channel bridging and signal regeneration of injured spinal cords显示文摘Due to the dificulty in spinal cord regeneration with biological methods,the microelectronic neural bridge,a new concept based on microelectronic technology,is presented.The microelectronic system has been realized in the forms of hybrid and integrated circuits.The integrated circuits forneural signal detection,stimulation,and regeneration are realized in a CMOS process.In animal experiments with 100 toads,48 rats,and 3 rabbits,nerve signals have been successfully detected from spinal cords and sciatic nerves,and functional electrical stimulation has been carried out for spinal cords and sciatic nerves.When the microelectronic system is bridged between the controlling and stimulated nerve,the relevant motion of legs and nerve signal waveforms,which are stimulated by the evoked or spontaneous nerve signal through such a system,have been observed.Therefore,the feasibility of the presented method was demonstrated.Zhigong Wang Xiaosong Gu Xiaoying Lǔ Zhenglin Jiang Wenyuan Li Guangming Lǔ Yufeng Wang Xiaoyan Shen Xintai Zhao Huiling Wang Zhenyu Zhang Hongmei Shen Yang Wu Weixing Shen Jingyang Zhang Dong Chen Xiaoyi Mao Huaxiang Shen 2009Progress in Natural Science:Materials International2009,19,10:5
10Photonic spin Hall effect on the surface of anisotropic two-dimensional atomic crystals显示文摘We examine the spin-orbit interaction of light and photonic spin Hall effect on the surface of anisotropic two-dimensional atomic crystals. As an example, the photonic spin Hall effect on the surface of black phosphorus is investigated. The photonic spin Hall effect manifests itself as the spin-dependent beam shifts in both transverse and in-plane directions. We demonstrate that the spin-dependent shifts are sensitive to the orientation of the optical axis, doping concentration, and interband transitions. These results can be extensively extended to other anisotropic two-dimensional atomic crystals. By incorporating the quantum weak measurement techniques, the photonic spin Hall effect holds great promise for detecting the parameters of anisotropic two-dimensional atomic crystals.WENSHUAI ZHANG WEIJIE WU SHIZHEN CHEN JIN ZHANG XIAOHUI LING WEIXING SHU HAILU LUO SHUANGCHUN WEN 2018Photonics Research2018,6,6:4
11Preliminary experimental results by the prototype of Sanya Incoherent Scatter Radar显示文摘In the past decades,the Incoherent Scatter Radar(ISR)has been demonstrated to be one of the most powerful instruments for ionosphere monitoring.The Institute of Geology and Geophysics at the Chinese Academy of Sciences was founded to build a state-ofthe-art phased-array ISR at Sanya(18.3°N,109.6°E),a low-latitude station on Hainan Island,named the Sanya ISR(SYISR).As a first step,a prototype radar system consisting of eight subarrays(SYISR-8)was built to reduce the technical risk of producing the entire large array.In this work,we have summarized the preliminary experimental results based on the SYISR-8.The amplitude and phase among 256 channels were first calibrated through an embedded internal monitoring network.The mean oscillation of the amplitude and phase after calibration were about 1 dB and 5°,respectively,which met the basic requirements.The beam directivity was confirmed by crossing screen of the International Space Station.The SYISR-8 was further used to detect the tropospheric wind profile and meteors.The derived winds were evaluated by comparison with independent radiosonde and balloon-based GPS measurements.The SYISR-8 was able to observe several typical meteor echoes,such as the meteor head echo,range-spread trail echo,and specular trail echo.These results confirmed the validity and reliability of the SYISR-8 system,thereby reducing the technical risk of producing the entire large array of the SYISR to some extent.XinAn Yue WeiXing Wan Han Xiao LingQi Zeng ChangHai Ke BaiQi Ning Feng Ding BiQiang Zhao Lin Jin Chen Li MingYuan Li JunYi Wang HongLian Hao Ning Zhang 2020Earth and Planetary Physics2020,4,6:3
12Diagnostic value of whole-body MRI with diffusion-weighted sequence for detection of peritoneal metastases in colorectal malignancy显示文摘Objective:To assess the diagnostic accuracy of whole-body MRI using diffusion-weighted sequence(WB-DWI)to determine the peritoneal cancer index(PCI)in correlation with surgical and histopathological findings.Methods:Twenty-seven patients underwent preoperative WB-MRI,followed by cytoreductive surgery for primary tumors of the appendix(n=15),colorectum(n=12),and associated peritoneal disease.A total of 351 regions were retrospectively reviewed.The sensitivity,specificity,and accuracy were calculated at 13 anatomical sites.The WB-DWI PCI and PCI type were compared with surgical and histopathological findings.Results:No statistical difference was found between the WB-DWI PCI and surgical PCI(P=0.574).WB-DWI correctly predicted the PCI type in 24 of 27 patients with high accuracy(88.9%),including 10 of 10 patients with small-volume tumor,12 of 14 with moderate-volume tumor,and 2 of 3 with large-volume tumor.WB-DWI correctly depicted tumors in 163 of 203 regions,with 40false-negative and 23 false-positive regions.The overall sensitivity,specificity,and accuracy of WB-DWI for the detection of peritoneal tumors were 80.3%,84.5%,and 82.1%,respectively.For lesions<0.5 cm in diameter,WB-DWI demonstrated good sensitivity(69.4%).Conclusions:WB-DWI accurately predicted PCI before surgery in patients undergoing evaluation for cytoreductive surgery.Huan Zhang Weixing Dai Caixia Fu Xu Yan Alto Stemmer Tong Tong Guoxiang Cai 2018Cancer Biology & Medicine2018,15,2:3
13Trifolirhizin induces autophagy-dependent apoptosis in colon cancer via AMPK/mTOR signaling显示文摘Dear Editor,Colorectal cancer(CRC)is one of the most frequent diseases with high mortality around the world.Conventional treatments of CRC remain unsatisfactory due to the increasing recurrence rate and adverse reactions including neutropenia,drug resistance,etc.Recently,autophagy has been shown to be involved in regulating cancer development and progression by regulating apoptosis through pro-apoptosis proteins including caspases,in addition to being a potential target for cancer therapeutic intervention.1 Trifolirhizin(Supplementary Fig.S1a)is a natural flavonoid glycosides isolated from Sophora flavescens as well as a bioactive constituent of Xian-Lian-Ke-Li,a commercial traditional Chinese medicine for the cancer prevention.Numerous evidence manifested that trifolirhizin inhibited proliferative activity in melanoma B16 cell,lung cancer H23 cell,human ovarian A2780 cell,and human gastric cancer cell MKN45.2 However,its pharmacological effect and mechanism on CRC remain elusive.Herein,we evaluated the effect of trifolirhizin on autophagy and apoptosis on CRC as well as its related mechanisms,in order to provide evidence to develop a potential agent with less adverse effect in treating CRC.Dongdong Sun Weiwei Tao Feng Zhang Weixing Shen Jiani Tan Liu Li Qinghai Meng Yugen Chen Ye Yang Haibo Cheng 2020Signal Transduction and Targeted Therapy2020,5,1:3
14Highly Efficient Surface-Search Algorithm for Adaptive FIR Filtering显示文摘ZHANG Bin ZHENG Weixing FENG Dazheng 2007Chinese Journal of Electronics2007,16,2:2
15TIME-IGGCAS model validation:Comparisons with empirical models and observations显示文摘The TIME-IGGCAS (Theoretical Ionospheric Model of the Earth in Institute of Ge- ology and Geophysics, Chinese Academy of Sciences) has been developed re- cently on the basis of previous works. To test its validity, we have made compari- sons of model results with other typical empirical ionospheric models (IRI, NeQuick-ITUR, and TItheridge temperature models) and multi-observations (GPS, Ionosondes, Topex, DMSP, FORMOSAT, and CHAMP) in this paper. Several conclu- sions are obtained from our comparisons. The modeled electron density and elec- tron and ion temperatures are quantitatively in good agreement with those of em- pirical models and observations. TIME-IGGCAS can model the electron density variations versus several factors such as local time, latitude, and season very well and can reproduce most anomalistic features of ionosphere including equatorial anomaly, winter anomaly, and semiannual anomaly. These results imply a good base for the development of ionospheric data assimilation model in the future. TIME-IGGCAS underestimates electron temperature and overestimates ion tem- perature in comparison with either empirical models or observations. The model results have relatively large deviations near sunrise time and sunset time and at the low altitudes. These results give us a reference to improve the model and enhance its performance in the future.YUE XinAn WAN WeiXing LIU LiBo NING BaiQi ZHAO BiQiang ZHANG ManLian 2008Science China(Technological Sciences)2008,51,3:2
16CPT-FDR: An Approach to Translating PPDDL Conformant Planning Tasks into Finite-Domain Representations显示文摘LI Weisheng ZHANG Zhen WANG Weixing 2012Chinese Journal of Electronics2012,21,1:2
17Biomarkers in the early period of acute myocardial infarction in rat serum and protective effects of Shexiang Baoxin Pill using a metabolomic method显示文摘Peng Jiang Weixing Dai Shikai Yan Zhongliang Chen Ruilin Xu Jianmi Ding Li Xiang Shuping Wang Runhui Liu Weidong Zhang 2011Journal of Ethnopharmacology2011,,2:2
18Experimental study on enhancement of the metastatic potential of portal vein tumor thrombus-originated hepatocellular carcinoma cells using portal vein serum显示文摘Objective: Portal vein metastasis of hepatocellular carcinoma(HCC) results in a poor prognosis and seriously affects the survival rate of patients. The mechanism underlying the formation of portal vein tumor thrombus(PVTT) is complex and is not yet fully understood. This study was conducted to investigate the impact of portal vein blood on the proliferation, metastasis, invasion and apoptosis of PVTT cells and to explore its possible mechanisms, which was expected to lay a foundation for ascertaining the mechanism underlying the portal vein metastasis of HCC.Methods: Peripheral blood and portal vein blood were collected from patients with HCC, and the sera from these two sources were used to culture the PVTT-originated HCC cell line CSQT-2. The cells were collected after 24 h, and flow cytometry was performed to detect cell proliferation, cell cycle stages and apoptosis. Transwell migration and invasion assays were applied to detect the metastasis and invasion of the cells in each group. The changes in the expression of MMP-2 and MMP-9 in cells were detected via Western blotting. The contents of IL-12, IFN-γ, IL-1β, IL-2 and TNF-α in the two groups of sera were quantified using corresponding kits. Results: Compared with the group of cells cultured with peripheral serum, the cells cultured with portal vein serum showed significantly lower apoptosis(P<0.01), significantly enhanced cell metastasis and invasion(P<0.01), whereas cell proliferation and the stages of the cell cycle did not differ significantly(P>0.05). A significantly increased expression level of MMP-2 has been observed in tumor cells treated portal vein serum. In addition, compared with peripheral serum, the content of IL-12 was significantly decreased in portal vein serum(P<0.05), while the contents of IFN-γ, IL-1β, IL-2, and TNF-α did not differ significantly(P>0.05). Conclusions: Portal vein serum from HCC patients could inhibit the apoptosis of PVTT-originated HCC cells and promote cell metastasis and invasion. This effect may be related to the lower level of IL-12 in portal vein serum.Yufu Tang Hongming Yu Long Zhang Kang Wang Weixing Guo Jie Shi Shupeng Liu Mengchao Wu Hongyang Wang Shuqun Cheng 2014Chinese Journal of Cancer Research2014,26,5:2
19Chemical fingerprinting of Liuwei Dihuang Pill and simultaneous determination of its majorbioactive constituents by HPLC coupled with multiple detections of DAD, ELSD and ESI-MS显示文摘Ye Ji Zhang Xi Dai Weixing 2009J Pharm Biomed Anal2009,49,3:1
20The synthesis and characterization of thiophene derivative polymers显示文摘Chen Weixing Zhang Suyan Ma Aijie 2011Adv Mater Res2011,,4:1
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