维普中文期刊产品整合服务
118篇 您的检索式:作者名="Weiming Zhao"
    题名 作者 年代 出处 被引量
1Precise orbit determination of Beidou Satellites with precise positioning显示文摘Chinese Beidou satellite navigation system constellation currently consists of eight Beidou satellites and can provide preliminary service of navigation and positioning in the Asia-Pacific Region.Based on the self-developed software Position And Navigation Data Analysis(PANDA) and Beidou Experimental Tracking Stations (BETS),which are built by Wuhan University,the study of Beidou precise orbit determination,static precise point positioning (PPP),and high precision relative positioning,and differential positioning are carried out comprehensively.Results show that the radial precision of the Beidou satellite orbit determination is better than 10 centimeters.The RMS of static PPP can reach several centimeters to even millimeters for baseline relative positioning.The precision of kinematic pseudo-range differential positioning and RTK mode positioning are 2-4 m and 5-10 cm respectively,which are close to the level of GPS precise positioning.Research in this paper verifies that,with support of ground reference station network,Beidou satellite navigation system can provide precise positioning from several decimeters to meters in the wide area and several centimeters in the regional area.These promising results would be helpful for the implementation and applications of Beidou satellite navigation system.SHI Chuang ZHAO QiLe LI Min TANG WeiMing HU ZhiGang LOU YiDong ZHANG HongPing NIU XiaoJi LIU JingNan 2012Science China Earth Sciences2012,55,7:61
2Early Paleozoic subduction of the Paleo-Asian Ocean: Geochronological and geochemical evidence from the Dashizhai basalts, Inner Mongolia显示文摘Zircon U-Pb results of basalt from the Dashizhai Town in Inner Mongolia, NE China, shows that the basaltic lava was erupted at 439±3 Ma, much older than the 'Permian basalts' as previously thought. These rocks show arc-type trace element patterns (i.e., Nb-Ta depletion and light REE and large ion lithophile element enrichment) and unradiogenic Sr and highly radiogenic Nd and Hf isotope compositions. They can be subdivided into two petrogenetic groups: Group 1 basalts have relatively high TiO2, MgO and compatible elements and low Sr and Th, characterized by mid-oceanic ridge basalt (MORB)-type Sr-Nd-Hf isotope compositions (87Sr/86Sr(i)=0.7028―0.7032, εNd(t)=+9.8-+11.2, εHf(t)=+16.1- +18.4). Group 2 has lower TiO2, MgO and compatible elements and higher Sr and Th, and relatively evolved Sr-Nd-Hf isotope compositions (87Sr/86Sr(i)=0.7037-0.7038, εNd(t)=+5.7-+7.3, εHf(t)=+12.6- +13.0). Both groups were interpreted as melts derived from a metasomatized mantle wedge formed during the subduction of Paleo-Asian Ocean. The mantle source for Group 1 was probably a highly isotopically depleted oceanic mantle modified by predominant slab fluids; whereas subducted sediments had an important contribution to the melting source for Group 2. The petrogenesis of the Dashizhai basalts provides clear evidence for early Paleozoic subduction of the Paleo-Asian Ocean, and the highly radiogenic Nd and Hf compositions in these rocks suggest that these lavas and their possible intrusive counterparts were one of the important components for Phanerozoic crustal growth. Our and previous studies on the 'Dashizhai Formation' volcanic rocks yield an unrealistic eruption range of 440-270 Ma for different rock types, we thus advise to disassemble the previously defined 'Dashizhai Formation' into multiple lithologic units and to reinterpret the spatial and temporal distributions of different volcano-sedimentary associations.GUO Feng FAN WeiMing LI ChaoWen MIAO LaiCheng ZHAO Liang 2009Science China Earth Sciences2009,52,7:37
3Optimization design and test of rice plug seedling transplanting mechanism of planetary gear train with incomplete eccentric circular gear and non-circular gears显示文摘In order to solve the problem of the high-speed mechanized transplanting of rice plug seedlings,the design requirements of transplanting mechanism for rice plug seedlings were analyzed and a kind of rice plug seedling transplanting mechanism of planetary gear train based on the drive with incomplete eccentric circular gear and non-circular gears was designed innovatively.The laboratory kinematics was examined.The working principle of the transplanting mechanism for rice plug seedlings was studied,kinematics analysis of the transplanting mechanism was carried out and its kinematic model was set up.A human-computer interaction optimization method was used to optimize the parameters of the transplanting mechanism.The computer aided analysis and optimization software of the transplanting mechanism based on Visual Basic 6.0 was developed.Through analyzing the influence of design variables on the optimization objectives of the transplanting mechanism,a set of parameters of the transplanting mechanism which meet the requirements of transplanting trajectory and posture for transplanting rice seedlings were obtained by means of human-computer interaction.The structure of the transplanting mechanism was designed according to this set of parameters,and its virtual prototype and physical prototype were set up and manufactured,respectively.The kinematic simulation test and high-speed photography kinematic test of the transplanting mechanism were conducted to obtain its kinematic performances,such as transplanting trajectory and posture.The results of bench test,simulation analysis and theoretical analysis were almost in agreement,which verified the correctness of the theoretical model and design results of the transplanting mechanism,indicating that the optimized transplanting mechanism can satisfy the requirements of transplanting rice seedlings and be applied in the rice plug seedling transplanter.Ye Bingliang Yi Weiming Yu Gaohong Gao Yang Zhao Xiong 2017International Journal of Agricultural and Biological Engineering2017,10,6:31
4Research on semi-solid slurry of a hypoeutectic Al-Si alloy prepared by low superheat pouring and weak electromagnetic stirring显示文摘The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak elec- tromagnetic stirring. The effects of pouring temperature and stirring power on the semi-solid slurry were investigated. The results indicated that the semi-solid slurry to satisfy rheocasting can be manufactured by low superheat pouring and weak electromagnetic stirring. The pouring temperature (or superheat) and the stirring power remarkably affected the morphology of primary α-Al and the size of primary α-Al, and there is no obvious effect of stirring time on primary α-Al. Compared with the samples made by low superheat pouring with no stirring, the nucleation rate, particle morphology and grain size of primary α-Al in A356 were markedly improved by low superheat pouring and weak electromagnetic stirring. On the condi- tion of weak electromagnetic stirring, the pouring temperature with low superheat can be suitably raised to reach the effec- tiveness obtained from the lower pouring temperature without stirring.LIU Zheng MAO Weiming ZHAO Zhengduo 2006Rare Metals2006,25,2:21
5Crustal evolution of the Shiwandashan area in South China:Zircon U-Pb-Hf isotopic records from granulite enclaves in Indo-Sinian granites显示文摘标明日期的 U-Pb 在东南的 Guangxi 省从 Shiwandashan 区域在 Jiuzhou peraluminous 花岗石从 metasedimentary granulite 被外国领地包围的土地在锆石上结合了 Hf 同位素分析,华南在这份报纸被介绍。结果证明这些 granulite 被外国领地包围的土地的 protoliths 主要由有一座山峰的碎屑状的材料在 822 妈变老的 Neo-Mesoproterozoic (5641061 妈) 组成。这些材料可能从在 Rodinian Supercontinent 的 Neoproterozoic 决裂期间是 emplaced 的火的岩石被导出。辅助沉积包括 Paleoproterozoic (17782227 妈) ,有最旧的 U-Pb 的甚至 Meso-Paleoarchean 材料在 3551ZHAO Liang GUO Feng FAN WeiMing LI ChaoWen QIN XiaoFeng LI HongXia 2010Chinese Science Bulletin2010,55,19:18
6Research and compilation of the Geomorphologic Atlas of the People's Republic of China (1:1,000,000)显示文摘Geomorphologic maps are one of the most fundamental materials of the natural environment. They have been widely used in scientific research,resource exploration and extraction,education and military affairs etc. An editorial committee was established in 2001 to collect materials for researching and compiling a set of new 1:1,000,000 geomorphologic atlas of China. A digital geomorphologic database was created with visual interpretation from Landsat TM/ETM imageries and SRTM-DEM etc. The atlas compiled from the database was finished. The main characteristics of the atlas are as follows:Firstly,Landsat TM/ETM imageries,published geomorphologic maps or sketches,geographical base maps,digital geological maps,and other thematic maps were collected,which were uniformly geometrically rectified,clipped into uniform sheets,and stored in the foundation database. Secondly,based on the legends of 15 sheets 1:1,000,000 maps published in the 1980s,a geomorphologic classification system was built by combining morphology and genesis types. The system comprised seven hierarchical layers:basic morphology,genesis,sub-genesis,morphology,micro-morphology,slope and aspect,material composition and lithology. These layers were stored in the database during visual image interpretation. About 2000 kinds of morpho-genesis and 300 kinds of morpho-structure were interpreted. Thirdly,the legend system was built,which included color,symbol bases and note bases etc.,compilation standards and procedures were developed,74 sheets of 1:1,000,000 covering all land and sea territories of China were compiled,the 1:1,000,000 geomorphologic atlas of the People's Republic of China was finished and published. The atlas will fill the blanks in national basic scale thematic maps,and the geomorphologic database could be applied widely in many fields in the future.CHENG Weiming ZHOU Chenghu CHAI Huixia ZHAO Shangmin LIU Haijiang ZHOU Zengpo 2011Journal of Geographical Sciences2011,21,1:17
7One-step synthesis and electromagnetic absorption properties of high entropy rare earth hexaborides(HE REB6)and high entropy rare earth hexaborides/borates(HE REB6/HE REB03)composite powders显示文摘Considering the emergence of severe electromagnetic interference problems,it is vital to develop electromagnetic(EM)wave absorbing materials with high dielectric,magnetic loss and optimized impedance matching.However,realizing the synergistic dielectric and magnetic losses in a single phase material is still a challenge.Herein,high entropy(HE)rare earth hexaborides(REB6)powders with coupling of dielectric and magnetic losses were designed and successfully synthesized through a facial one-step boron carbide reduction method,and the effects of high entropy borates intermedia phases on the EM wave absorption properties were investigated.Five HE REB6 ceramics including(Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6,(Ce0.2Hu0.2Sm0.2Er0.2Yb0.2)B6,(Ce0.2Y0.2Eu0.2Er0.2Yb0.2)B6,(Ce0.2Ya2Sm0.2Eu0.2Yb0.2)B6,and(Nd0.2Y0.2Sm0.2Eu0.2Yb0.2)B6 possess CsCl-type cubic crystal structure,and their theoretical densities range from 4.84 to 5.25 g/cm^(3).(Ce02Y0.2Sm0.2Er0.2Yb02)B6 powders with the average particle size of 1.86 jim were found to possess the best EM wave absorption properties among these hexaborides.The RLmin value of(Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6 reaches-33.4 dB at 11.5 GHz at thickness of 2 mm;meanwhile,the optimized effective absorption bandwidth(EAB)is 3.9 GHz from 13.6 to 17.5 GHz with a thickness of 1.5 mm.The introduction of HE REB03(RE=Ce,Y,Sm,Eu,Er,Yb)as intermediate phase will give rise to the mismatching impedance,which will further lead to the reduction of reflection loss.Intriguingly,the HEREB6/HEREB03 still possess wide effective absorption bandwidth of 4.1 GHz with the relative low thickness of 1.7 mm.Considering the better stability,low density,and good EM wave absorption properties,HE REB6 ceramics are promising as a new type of EM wave absorbing materials.Weiming ZHANG Biao ZHAO Huimin XIANG Fu-Zhi DAI Shijiang WU Yanchun ZHOU 2021Journal of Advanced Ceramics2021,10,1:15
8High entropy rare earth hexaborides/tetraborides(HE REB_(6)/HE REB_(4)) composite powders with enhanced electromagnetic wave absorption performance显示文摘The increasing electromagnetic hazards including electromagnetic interference and electromagnetic pollution,which were stemmed from massive usage of electromagnetic technology,have triggered widespread concerns.To cope with this challenge,electromagnetic wave absorbing materials with high performance are greatly needed.Composite construction has been widely applied in electromagnetic(EM)wave absorbing materials to achieve high permittivity,high permeability and impedance matching.However,high-temperature stability,oxidation and corrosion resistance are still unignorable issues.Herein,high entropy hexaborides/tetraborides(HE REB_(6)/HE REB_(4))composites with synergistic dielectric and magnetic losses were designed and successfully synthesized through a one-step boron carbide reduction method.The five as-prepared(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(4),(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(4),(Y_(0.2) Nd_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(4),(Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(4) and(Y_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2) Yb_(0.2))B_(4) contain two phases of HE REB_(6) and HE REB_(4).Among them(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Eu_(0.2) Er_(0.2))B_(4)(HE REB_(6)/HE REB_(4)-1)and(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(6)/(Y_(0.2) Nd_(0.2) Sm_(0.2) Er_(0.2) Yb_(0.2))B_(4)(HE REB_(6)/HE REB_(4)-2)exhibit excellent EM wave absorption properties.The optimal minimum reflection loss(RL_(m in))and effective absorption bandwidth(E_(AB))of HE REB_(6)/HE REB_(4)-1 and HE REB_(6)/HE REB_(4)-2 are–53.3 dB(at 1.7 mm),4.2 GHz(at 1.5 mm)and–43.5 dB(1.3 mm),4.2 GHz(1.5 mm),respectively.The combination of conducting HE REB_(4) with magnetism into HE REB_(6) as a second phase enhances dielectric and magnetic losses,which lead to enhanced EM wave absorption performance.Considering superior high-temperature stability,oxidation and corrosion resistance of HE REB_(6) and HE REB_(4),HE REB_(6)/HE REB_(4) composite ceramics are promising as a new type of high-performance EM wave absorbing materials.Weiming Zhang Biao Zhao Na Ni Huimin Xiang Fu-Zhi Dai Shijiang Wu Yanchun Zhou 2021Journal of Materials Science & Technology2021,,28:9
9Automatic extraction of lunar impact craters from Chang'E-1 satellite photographs显示文摘The distribution characteristics of the impact craters can provide a large amount of information on impact history and the lunar evolution process. In this research, based on the digital elevation model (DEM) data originating from Change'E-1 CCD stereo camera, three automatic extraction methods for the impact craters are implemented in two research areas: direct extraction from flooded DEM data (the Flooded method), object-oriented extraction from DEM data by using ENVI ZOOM function (the Object-Oriented method) and novel object-oriented extraction from flooded DEM data (the Flooded Object-Oriented method). Accuracy assessment, extracted degree computation, cumulative frequency analysis, shape and age analysis of the extracted craters combined display the following results. (1) The Flooded Object-Oriented method yields better accuracy than the other two methods in the two research areas; the extraction result of the Flooded method offers the similar accuracy to that of the Object-Oriented method. (2) The cumulative frequency curves for the extracted craters and the confirmed craters share a similar change trajectory. (3) The number of the impact craters extracted by the three methods in the Imbrian period is the largest and is of various types; as to their age earlier than Imbrain, it is difficult to extract because they could have been destroyed.WAN Cong CHENG WeiMing ZHOU ZengPo ZHAO ShangMin XIA Yao 2012Science China(Physics,Mechanics & Astronomy)2012,55,1:8
10Assessment of the immune responses to Treponema pallidum Gpd DNA vaccine adjuvanted with IL-2 and chitosan nanoparticles before and after Treponema pallidum challenge in rabbits显示文摘Syphilis is a multistage,sexually transmitted disease caused by the spirochete,Treponema pallidum(Tp).A significantly high incidence of syphilis has been reported in several countries,including China,and there is an urgent need for the development of efficacious vaccines against syphilis.DNA vaccines are a major breakthrough in the field of vaccination with several advantages over traditional vaccines.Animal model studies of Tp DNA vaccines have not been reported elsewhere but our previous reports describe the development of a single-gene Tp DNA vaccine and preclinical immunization study.In this study,chitosan(CS) nanoparticles were used as a vector and an interleukin-2 expression plasmid(pIL-2) as an adjuvant to enhance a TpGpd DNA vaccine candidate(pTpGpd) in a rabbit Tp skin challenge model.At week 8 after the first immunization,three rabbits from each group were used to determine cytokine measurements and spleen lymphocyte proliferation assay.pTpGpd in combination with pIL-2 wrapped with CS led to the greatest enhancement of anti-TpGpd antibodies and T-cell proliferation.During infection,levels of anti-TpGpd antibodies and T-cell proliferation were measured.Both the serum special IgG and IL-2,interferon-γ were significantly increased by the co-injection of the IL-2 plasmid compared with the injection of TpGpd DNA alone(P<0.05).Furthermore,IL-2 plasmid coinjection efficiently enhanced the antigen-specific lymphocyte proliferation response.Additionally,the ratios of positive skin lesions and ulcer lesions in groups immunized with pTpGpd were significantly lower than those of the pIL-2,CS or pIL-2 mixed with CS control groups(P<0.001).CS vectored and pIL-2 adjuvanted pTpGpd immunized animals exhibited the lowest rates of positive skin tests(8.33%) and ulcer lesions(4.17%) and the fastest recovery(42 d).These experiments indicate that co-injection of a pIL-2 plasmid with pTpGpd DNA vaccine wrapped with CS can significantly strengthen the long-term stability of immune response during infection,efficiently improve the protective effect against T.pallidum spirochetes infection and attenuate syphilitic lesion development.ZHAO FeiJun ZHANG XiaoHong LIU ShuangQuan ZENG TieBing YU Jian GU WeiMing ZHANG YueJun CHEN Xi WU YiMou 2013Science China(Life Sciences)2013,56,2:8
11Climate effects on an inland alpine lake in Xinjiang, China over the past 40 years显示文摘Inland lakes are important water resources in arid and semiarid regions. Understanding climate effects on these lakes is critical to accurately evaluate the dynamic changes of water resources. This study focused on the changes in Sayram Lake of Xinjiang, China, and addressed the effects of climate fluctuations on the inland lake based on long-term sequenced remote sensing images and meteorological data from the past 40 years. A geographic information system (GIS) method was used to obtain the hypsometry of the basin area of Sayram Lake, and estimation methods for evaporation from rising temperature and water levels from increasing precipitation were proposed. Results showed that: (1) Areal values of Sayram Lake have increased over the past 40 years. (2) Both temperature and precipitation have increased with average increases of more than 1.8℃ and 82 mm, respectively. Variation of the water levels in the lake was consistent with local climate changes, and the areal values show linear relationships with local temperature and precipitation data. (3) According to the hypsometry data of the basin area, the estimated lake water levels increased by 2.8 m, and the water volume increased by 12.9×10 8 m3 over the past 40 years. The increasing area of Sayram Lake correlated with local and regional climatic changes because it is hardly affected by human activities.HuiXia CHAI WeiMing CHENG ChengHu ZHOU ShangMin ZHAO HaiJiang LIU 2013Journal of Arid Land2013,5,2:7
12Theoretical analysis of a new segmented anchoring style in weakly cemented soft surrounding rock显示文摘According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large deformation. Firstly, a segmented mechanical model was established in which free and anchoring section of rock bolt were respectively arranged in different deformation zones. Then, stress and displacement in elastic non-anchoring zone, elastic anchoring zone, elastic sticking zone, softening sticking zone and broken zone were derived respectively based on neural theory and tri-linear strain softening constitutive model of soft rock. Results show that the anchoring effect can be characterized by a supporting parameter b. With its increase, the peak value of tangential stress gradually moves to the roadway wall, and the radial stress significantly increases, which means the decrease of equivalent plastic zone and improvement of confining effect provided by anchorage body. When b increases to 0.72, the equivalent plastic zone disappears, and stresses tend to be the elastic solutions. In addition, the anchoring effect on the displacement of surrounding rock can be quantified by a normalization factor δ.Zhao Zenghui Wang Weiming Wang Lihua 2016International Journal of Mining Science and Technology2016,26,3:7
13Growth of the Sayram Lake and retreat of its water-supplying glaciers in the Tianshan Mountains from 1972 to 2011显示文摘Inland lakes and alpine glaciers are important constituents of water resources in arid and semiarid regions. Understanding their variations is critical for both an accurate evaluation of the dynamic changes of water resources and the retrieval of climatic information. On the basis of earlier researches, this study investigated the growth of the Sayram Lake and the retreat of its water-supplying glaciers in the Tianshan Mountains using long-term sequenced remote sensing images. Our results show that over the past 40 years, the surface area and the water level of the lake has increased by 12.0±0.3 km2 and 2.8 m, respectively, and the area of its water-supplying glaciers has decreased continuously since the early 1970 s with a total reduction of about –2.13±0.03 km2. Our study has indicative significance to the research of regional climate change.CHENG Weiming WANG Nan ZHAO Shangmin FANG Yue ZHAO Min 2016Journal of Arid Land2016,8,1:6
14Achieving ultra-broadband electromagnetic wave absorption in high-entropy transition metal carbides (HE TMCs)显示文摘Electronic devices pervade everyday life,which has triggered severe electromagnetic(EM)wave pollution.To face this challenge,developing EM wave absorbers with ultra-broadband absorption capacity is critically required.Currently,nano-composite construction has been widely utilized to realize impedance match and broadband absorption.However,complex experimental procedures,limited thermal stability,and interior oxidation resistance are still unneglectable issues.Therefore,it is appealing to realize ultra-broadband EM wave absorption in single-phase materials with good stability.Aiming at this target,two high-entropy transition metal carbides(HE TMCs)including(Zr,Hf,Nb,Ta)C(HE TMC-2)and(Cr,Zr,Hf,Nb,Ta)C(HE TMC-3)are designed and synthesized,of which the microwave absorption performance is investigated in comparison with previously reported(Ti,Zr,Hf,Nb,Ta)C(HE TMC-1).Due to the synergistic effects of dielectric and magnetic losses,HE TMC-2 and HE TMC-3 exhibit better impedance match and wider effective absorption bandwidth(EAB).In specific,the exclusion of Ti element in HE TMC-2 endows it optimal minimum reflection loss(RL_(min))and EAB of−41.7 dB(2.11 mm,10.52 GHz)and 3.5 GHz(at 3.0 mm),respectively.Remarkably,the incorporation of Cr element in HE TMC-3 significantly improves the impedance match,thus realizing EAB of 10.5,9.2,and 13.9 GHz at 2,3,and 4 mm,respectively.The significance of this study lays on realizing ultra-broadband capacity in HE TMC-3(Cr,Zr,Hf,Nb,Ta),demonstrating the effectiveness of high-entropy component design in tailoring the impedance match.Weiming ZHANG Huimin XIANG Fu-Zhi DAI Biao ZHAO Shijiang WU Yanchun ZHOU 2022Journal of Advanced Ceramics2022,11,4:5
15Enabling highly efficient and broadband electromagnetic wave absorption by tuning impedance match in high-entropy transition metal diborides (HETMB_(2))显示文摘The advance in communication technology has triggered worldwide concern on electromagnetic wave pollution.To cope with this challenge,exploring high-performance electromagnetic(EM)wave absorbing materials with dielectric and magnetic losses coupling is urgently required.Of the EM wave absorbers,transition metal diborides(TMB2)possess excellent dielectric loss capability.However,akin to other single dielectric materials,poor impedance match leads to inferior performance.High-entropy engineering is expected to be effective in tailoring the balance between dielectric and magnetic losses through compositional design.Herein,three HE TMB2 powders with nominal equimolar TM including HE TMB2-I(TM=Zr,Hf,Nb,Ta),HE TMB2-2(TM=Ti,Zr,Hf,Nb,Ta),and HE TMB2-3(TM=Cr,Zr,Hf,Nb,Ta)have been designed and prepared by one-step boro/carbothermal reduction.As a result of synergistic effects of strong attenuation capability and impedance match,HE TMB2-1 shows much improved performance with the optimal minimum reflection loss(RL_(min))of-59.6 dB(8.48 GHz,2.68 mm)and effective absorption bandwidth(EAB)of 7.6 GHz(2.3 mm).Most impressively,incorporating Cr in HE TMB2-3 greatly improves the impedance match over 1-18 GHz,thus achieving the RLmin of-56.2 dB(8.48 GHz,2.63 mm)and the EAB of 11.0 GHz(2.2 mm),which is superior to most other EM wave absorbing materials.This work reveals that constructing high-entropy compounds,especially by incorporating magnetic elements,is effectual in tailoring the impedance match for highly conductive compounds,i.e.,tuning electrical conductivity and boosting magnetic loss to realize highly efficient and broadband EM wave absorption with dielectric and magnetic coupling in single-phase materials.Weiming ZHANG Fu-Zhi DAI Huimin XIANG Biao ZHAO Xiaohui WANG Na NI Rajamallu KARRE Shijiang WU Yanchun ZHOU 2021Journal of Advanced Ceramics2021,10,6:4
16Research and perspectives on geomorphology in China: Four decades in retrospect显示文摘Geomorphology is one of the main subdisciplines of geography.The research achievements and prospects in geomorphology have received considerable attention for a long time.In this paper,a general retrospect of geomorphologic research in China over the past 60 years was firstly addressed,especially the research progress during the last 40 years.Based on a summary of experience and a tendency of development,perspectives of geomorphologic research direction in the future were provided.It is concluded that the discipline of geomorphology has made great progress in the aspects of geomorphologic types,regionalization,as well as their subdisciplines such as dynamic geomorphology,tectonic geomorphology,climatic geomorphology,lithological geomorphology,palaeogeomorphology.We believe that persisting in the unity principle between morphological and genetic types would be conductive for the development of traditional landforms and integrated landforms.In addition,five perspectives aim to enhance China’s geomorphologicl research capacity were proposed.They are:(1)strengthening the research of basic geomorphologic theory and the research of integrated geomorphology to expand the research space;(2)focusing more on the research of geomorphologic structure and geomorphologic function to improve the application ability of geomorphology;(3)constructing a comprehensive resource,environmental,and geomorphologic information system and building a sharing platform to upgrade the intelligent information industry of geomorphology;(4)putting more efforts on the research of coastal geomorphology and marine geomorphology to assist the transformation of China from a maritime country to an ocean power;and(5)cultivating talents and constructing research teams to maintain a sustainable development of China’s geomorphologic research.CHENG Weiming LIU Qiangyi ZHAO Shangmin GAO Xiaoyu WANG Nan 2017Journal of Geographical Sciences2017,27,11:3
17Highly stable and antifouling graphene oxide membranes prepared by bio-inspired modification for water purification显示文摘Graphene oxide(GO)membranes show great potential in molecular separation for water treatment.However,the inferior stability of GO membranes is a major bottleneck for practical applications.In this study,bio-inspired polydopamine(PDA)deposition is reported for enhancing the stability of GO membranes.Through simple and mild immersion,PDA is self-polymerized on GO membranes.The blocking of PDA chains to membrane defects improves the rejections for various molecules.Because the inherently strong adhesion and crosslinking of PDA greatly strengthen the interactions of substrates to GO layers and the binding force of GO nanosheets,the prepared PDA-GO membranes exhibit impressive long-te rm stability in cross-flow filtration,and maintain good nanofiltration perfo rmance at various feed pressures,tangential velocities,and eve n after external scratching.Moreover,because the deposited PDA layers obstruct the direct contact between GO and contaminants,the antifouling property of the PDA-GO membranes increases substantially,with recovery ratio about 98%.Weiming Zhong Yuyu Zhang Ling Zhao Wanbin Li 2020Chinese Chemical Letters2020,31,10:3
18Periurethral Injection of Autologous Adipose-Derived Stem Cells with Controlled-Release Nerve Growth Factor for the Treatment of Stress Urinary Incontinence in a Rat Model显示文摘Weiming Zhao Cheng Zhang Chengjun Jin Zijian Zhang Deling Kong Wanhai Xu Youcheng Xiu 2010European Urology2010,,1:2
19Nitrogen runoff dominates water nitrogen pollution from rice-wheat rotation in the Taihu Lake region of China显示文摘Xu Zhao Yang Zhou Ju Min Shenqiang Wang Weiming Shi Guangxi Xing 2012Agriculture Ecosystems and Environment2012,,:2
20A survey of HIV infection and related high-risk factors among men who have sex with men in Suzhou,Jiangsu,China显示文摘A cross-sectional study using the snowball sampling method was conducted in May 2008 to investigate human immunodeficiency virus (HIV) infection status and related high risk factors among men who have sex with men (MSM) in Suzhou city of Jiangsu province. The researchers carried out a face-to-face questionnaire interview among MSM, and collected their blood samples to test for HIV and other sexually transmitted diseases (STDs). Among the 280 respondents, 91.1% had homosexual acts in the past 6 months and 87.5% had multiple homosexual partners; 46.4% had heterosexual sex in the past 6 months and 33.1% had multiple heterosexual partners. The rate of continued condom use was 44.3% in homosexual sex in the past 6 months, while the rate in heterosexual sex was 33.9%. Laboratory test results showed that the prevalences of HIV and syphilis were 7.1% (20/280) and 15.0% (42/280), respectively, but no HCV-positive person was found. In the multivariate logistic regression model, subjects with a monthly income of more than RMB $ 1,000 (OR=4.83,95% CI=1.44-16.22), subjects who often went to bars for sexual partners (OR=2.25, 95%CI=1.21-4.20), and subjects who had more than one sexual partner in the past 6 months (OR=0.49, 95%CI=0.25-0.97) and had sex with fixed sexual partners in the past 6 months (OR=0.42, 95%CI=0.25-0.75) were significantly associated with the rate of continued condom use in homosexual sex in the past 6 months. Unprotected sex and multiple sexual partners were more common among MSM in Suzhou city; furthermore, the prevalences of HIV infection and syphilis were relatively high. HIV preventive measures should be designed to address these risk factors and control the spread of HIV among MSM.Hongling Bai Xiping Huan Weiming Tang Xin Chen Hongjing Yan Xiaoyan Liu Haitao Yang Zhihang Peng Xiuping Zhao Rongbin Yu Hao Yu Feng Chen 2011The Journal of Biomedical Research2011,25,1:2
返回顶部 每页显示:
共6页 首页 上一页 第1页 下一页 末页 /6 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费