检索结果-南通市图书馆

Simulation on C/A codes and analysis of GPS/pseudolite signals acquisition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2009年第5期52卷 1459-1462页

作者： ZHANG Lei shanghai institute of Technical physics,chinese academy of sciences,shanghai 200083,china shanghai institute of Technical physics Chinese Academy of Sciences Shanghai 200083 China

The global positioning system(GPS) is an extremely mature technique in the navigation and position-ing ***,there are still some limits in some aspects and for some special ***-cially,the performance of GPS needs to be improved with technological *** a GPS-like ground transmitter,the pseudolite provides a new research direction to achieve high positioning ac-curacy and *** this paper,we describe the core technologies of designing and simulation on the coarse acquisition codes in constructing the pseudolite *** the GPS/pseudolite integration system,the signal PRN 36 of the pseudolite and the GPS satellites signals are acquired in the modified receiver based on the computer software *** is shown that the pseudolite technology is ideally suited to augment the GPS alone and provide greater integrity,availability,and continuity of the navi-gation positioning system,especially for indoor use.

关键词： GPS pseudolite coarse acquisition(C/A) code acquisition

Simulations for optimization of SSRF BPM

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2003年第4期14卷 222-225页

作者： YANG Nuo, LIU Gui-Min (shanghai institute of applied physics, the chinese academy of sciences, shanghai 2.1800) shanghai institute of applied physics the Chinese Academy of Sciences 上海 201800

The wake field, impedance and output signal for SSRF BPM have been calculated and analyzed by us-ing the numerical simulation code of MAFIA. The narrow-band impedance of BPM arising from formation of reso-nance in its cavity like structure either is harmful to beam or limits the performance of BPM itself, and should be re-duced to tolerable levels. The calculated results show that there are three main peaks in the impedance spectrum ofthe SSRF BPM prototype, and two of which are above the limit. After lots of simulations for different shapes of theBPM button, a new structure of SSRF BPM have been found, and there is only one main peak, which is under thelimit, in the impedance spectrum. Its output signal also meets the requirement.

关键词：数值模拟耦合阻抗 BPM 上海同步加速器辐射装置 SSRF 束定位监视器 MAFIA模型

Experimental research on the residual magnetization of a rare-earth permanent magnet for a cryogenic undulator

在线全文

学校读者我要写书评

暂无评论

chinese physics B 2013年第7期22卷 180-182页

作者：何永周 shanghai institute of applied physics Chinese Academy of Sciences

The magnetic properties of commercial polycrystalline Nd2Fe14B （N50M,N45H,N40SH,N35EH） and Sm2Co17（XG30/20,XG26/25,XG22/20） magnets at cryogenic temperatures were tested by using a comprehensive physical properties measurement system （PPMS）. The results show that the spin tilt temperature Tst of Nd2Fe14B magnets is closely related to intrinsic coercivity Hci , N50M and N45H with smaller Hci show a residual magnetization jump at 235K and 225K, respectively. For Sm2Co17 magnets, in 50-300 K, with temperature decreasing, residual magnetization Mrc shows a nearly linear increase, while in 10-50 K, Mrc has little change. The research results provide a reference for cryogenic undulators and other high-precision cryogenic devices.

关键词： Nd2Fe14B and Sm2Co17 spin reorientation residual magnetization intrinsic coercivity

Synthesis of O-(2-[^(18)F]fluoroethyl)-L-tyrosine and its biological evaluation in B16 melanoma-bearing mice as PET tracer for tumor imaging

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2007年第2期50卷 276-283页

作者： WANG MingWei,YIN DuanZhi,LI ShiQiang & WANG YongXian Radiopharmaceutical Centre,shanghai institute of applied physics,chinese academy of sciences,shanghai 2.1800,china 1. Radiopharmaceutical Centre Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China

O-(2-[18F]fluoroethyl) -L-tyrosine([18F]FET) ,a fluorine-18 labeled analogue of tyrosine,has been syn-thesized and biologically evaluated in tumor-bearing mice. The whole synthesis procedure is com-pleted within 50 min. The radiochemical yield is about 40%(no decay corrected) and radiochemical purity more than 97% after simplified solid phase extraction. [18F]FET shows rapid,high uptake and long retention in the tumor as well as low uptake in the brain. The ratios of tumor-to-muscle(T/M) and tumor-to-blood(T/B) of [18F]FET are similar to those of [18F]FDG,but the ratios of tumor-to-brain(T/Br) are 2-3 times higher than that of [18F]FDG. Autoradiography of [18F]FET demonstrates a remarkable accumulation in melanoma with high contrast. It appears to be a probable competitive candidate for melanoma imaging with PET.

关键词： [18F]FET [18F]FDG PET imaging melanoma autoradiography

X-ray Powder Diffraction Pattern of Bi_4(SiO_4)_3

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第2期13卷 145-148页

作者： Hongchao LIU Changlin KUO (shanghai institute of Ceramics, chinese academy of sciences, shanghai 200050, china) shanghai institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figure-of-merits, which qualify agreement between observed and calculated relative intensities. F30 is 158.90 (0.0059, 32), intensity figure of merit Rint is 8.7, I20(17), 8.0. The values of figure-of-merits show that the data of JCPDS cards are distorted. Both the experimental and calculated peak positions and heights are listed in detail.

关键词： SiO4 X-ray Powder Diffraction Pattern of Bi4 Bi

Valence Distribution in AT_xV_(6-X)O_(11) Compounds

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1999年第6期15卷 551-554页

作者： Hongchao LIU and Changlin KUO(shanghai institute of Ceramics, chinese academy of sciences, shanghai 200050, china) chinese Acad Sci Shanghai Inst Ceram Shanghai 200050 Peoples R China

The distribution of trivalent and tetravalent cations in several ATxV6-xO11 compounds was quantitatively studied by the bond valence method. In SrV6O11, the M(3) sites were mainly occupied by trivaient cations; while M(1) and M(2) sites were shared by trivalent and tetravalent cations, the relative content of tetravalent at M(1) sites was higher than at M(2) sites. During substitution process, the trivalent cations preferred to occupy M(3) sites, tetravalent ones preferred to occupy M(2) sites. The occupancy of trivalent and tetravalent cations at M sites would change with the substitution

关键词： AT X)O Valence Distribution in AT_xV Compounds

Cytotoxicity of carbon nanotubes

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2008年第11期51卷 1021-1029页

作者： ZHU Ying1,2 & LI WenXin1 1 Laboratory of Nano-biology and Medicine, shanghai institute of applied physics, chinese academy of sciences, shanghai 2.1800, china 2 Graduate School of chinese academy of sciences, Beijing 100049, china 1. Laboratory of Nano-biology and Medicine Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China 2. Graduate School of chinese academy of sciences Beijing 100049 China

With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained, lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However, experimental information obtained thus far on CNTs' cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTs in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs' cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

关键词： carbon nanotubes (CNTs) cell bio-security

Conus Peptides-A Rich Pharmaceutical Treasure

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2004年第11期36卷 713-723页

作者： Cheng-Zhong WANG and Cheng-Wu CHIinstitute of Biochemistry and Cell Biology, shanghai institute of Biological sciences, the chinese academy of sciences, shanghai 200031, china institute of Neuroscience, the chinese academy of sciences, shanghai 200031, china institute of Protein Research, Tongji University, shanghai 200092, china institute of Biochemistry and Cell Biology Shanghai Institute of Biological Sciences the Chinese Academy of Sciences institute of Neuroscience the Chinese Academy of Science institute of Protein Research Tongji University

Marine predatory cone snails (genus Conus) with over 500 species represent what is arguably the largest single genus of marine animals alive today. All Conus are venomous and utilize a complex mixture of Conus peptide... 详细信息

关键词： Conus peptide conotoxin neuropathic disorder pharmaceutical potency

Formation and Oxidation Resistance of Silicide Coatings for Mo and Mo-Based Alloys

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2001年第4期17卷 479-481页

作者： Yu WANG , Yunpeng LI and Xingfang HU shanghai institute of Ceramics, chinese academy of sciences, shanghai 200050, china chinese Acad Sci Shanghai Inst Ceram Shanghai 200050 Peoples R China

The forming process of silicide coatings on pure Mo and Mo-base alloys, obtained by the gas- phase deposition method. has been studied by examining the microstructure of coatings and the relationship between coating thickness and process parameters. It was shown that the growth of coatings was diffusion-controlled, the diffusion of silicon to be coated into Mo or Mo-base alloys was mainly responsible for the formation of silicide. The relationship between initial silicide thickness and oxidation resistance was also investigated, and the equation of service life of the coatings at high temperature in air is presented.

关键词： Mo Formation and Oxidation Resistance of Silicide Coatings for Mo and Mo-Based Alloys