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Analysis on the positioning precision of CAPS

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Science china(physics,Mechanics & Astronomy) 2009年第3期52卷 328-332页

作者： JI YuanFa1,2 & SUN XiYan1,2 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012. china 2 Applied Science and technology college, guilin university of Electronic technology, guilin 541004, china National Astronomical Observatories Chinese Academy of Sciences Beijing China Applied Science and technology college Guilin University of Electronic Technology Guilin China

As a newly developed satellite positioning system, the Chinese Area Positioning System (CAPS) is a typical direct sequence spread spectrum ranging system like GPS. The positioning precision of such navigation signals depends on many factors, including the pseudo-code rate, the signal to noise ratio, the processing methods for tracking loops and so on. This paper describes the CAPS link budget, the solution approach for CAPS positioning, focusing on the autocorrelation function feature of C/A code signals. The CAPS signal measurement precision is studied by the software approach together with theoretical analysis of the range resolution. Because the conventional Delay Lock Loop (DLL) is vul- nerable to the impact of noise, a narrow correlator and multiple correlators as well as the corresponding discrimination methods of phases are proposed, which improves the robustness of DLL and the code-phase resolution of the measurement. The results show that the improvement of the DLL structure and the discrimination method are the most important way to improve the ranging resolution. Theoretical analysis and experimental results show that a CAPS receiver could reach a 20-m positioning precision by using three satellites with a supported height from an altimeter.

关键词： satellite navigation receiver narrow correlation tracking loop

Investigation of nano-talc as a filling material and a reinforcing agent in high density polyethylene (HDPE)

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Rare Metals 2006年第Z1期25卷 422-425页

作者： CHEN Nanchun MA Lei ZHANG Tao Center for Material Engineering Guilin Institute of Technology Guilin 541004 China Key Laboratory of Nonferrous Materials and Processing technology Ministry of Education Guilin Institute of Technology Guilin 541004 China Department of Physics and Information Technology Yulin Teachers'' College Yulin 537000 China Center for Material Engineering Guilin Institute of Technology Guilin 541004 China Key Laboratory of Nonferrous Materials and Processing technology Ministry of Education Guilin Institute of Technology Guilin 541004 China

An experiment of producing high density polyethylene (HDPE) nano-composite filled with 4wt.% talc was presented. Acting as filler and a reinforcing agent in the HDPE, talc powder, sized at around 5 μm, was surface-treated with aluminum diethylene glycol dinitrate coupling agent before adding to the HDPE. Analyses of the reinforced HDPE nano-composite show significant improvement in its mechanical properties including, tensile strength (>26 MPa), break elongation (22 MPa), and friction coefficients<0.11. The results demonstrate that, after surface-treated, talc can be used as a promising filling material and a reinforcing agent in making HDPE nano-composite.

关键词： HDPE talc filling material reinforcing agent nano-composite mechanical properties

Gamma-ray bursts in the Swift-Fermi era:Confronting data with theory

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Science china(physics,Mechanics & Astronomy) 2010年第S1期53卷 14-23页

作者： LIANG EnWei Physical Science & technology college,guangxi university,Nanning 530004,china Physical Science & technology college Guangxi University Nanning China

With the prompt slewing capability of the X-ray and UV-optical telescopes onboard the Swift mission and with the gamma-ray large area telescope onboard the Fermi mission,gamma-ray bursts(GRBs) are now accessible in a full time window and in all electromagnetic wavelengths for the *** observational breakthroughs have been made in recent years.I present here a brief review of some observational breakthroughs with the two missions,focusing on how these breakthroughs have revolutionized our understanding of the nature of this phenomenon and puzzles as well as challenges of confronting the conventional models with data.

关键词： radiation mechanism gamma rays bursts high energy phenomenon

A new grid-associated algorithm in the distributed hydrological model simulations

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Science china(Technological Sciences) 2010年第1期53卷 235-241页

作者： XU Rui1,2,HUANG XiaoXue1,LUO Lin1 & LI ShaoCai3 1 State Key Laboratory of Hydraulics and Mountain River Engineering college of Architecture and Environment,Sichuan university,Chengdu 610065,china 2 college of Electronic Engineering,guilin university of Electronic technology,guilin 541004,china 3 college of Life Sciences,Sichuan university,Chengdu 610065,china State Key Laboratory of Hydraulics and Mountain River Engineering college of Architecture and Environment Sichuan University Chengdu China college of Electronic Engineering Guilin University of Electronic Technology Guilin China college of Life Sciences Sichuan University Chengdu China

This paper presents a new grid-associated algorithm to improve the performance of a D8 algorithm based distributed hydrological model *** algorithm is based on the well known single-flow D8 algorithm of grid *** algorithm allocates calculation priorities according to the distance between the units and the outlet,then carries out the ergodic computations of the hydrological units according to the priority *** the parallelized algorithm,a standard thread-level shared memory system for parallel programming(OpenMP-Open specifications for Multi Processing) was introduced,and the parallel coding was implemented in C lan-guage.A case study showed that the absolute speed-up ratio of the grid-associated algorithm is 1.64 over the original D8 algorithm,and the linear speed-up ratio of the parallel associated algorithm is 2.42 under 4 *** parallel grid-associated algorithm can be applied to a variety of research fields that use the grid method.

关键词： distributed hydrological model grid-association algorithm OpenMP parallel computing

The new insights of hyperbaric oxygen therapy:focus on inflammatory bowel disease

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Precision Clinical Medicine 2024年第2期7卷 159-169页

作者： Leilei Chen Yan Wang Huihui Zhou Yi Liang Fengqin Zhu guangxi Zhou Cheeloo college of Medicine Shandong UniversityJinan 250012China Department of Gastroenterology Affliated Hospital of jining Medical University Jining Medical UniversityJining 272000China Department of Hyperbaric Oxygen Affliated Hospital of jining Medical UniversityJining Medical UniversityJining 272000China

Inflammatory bowel diseases(IBD),with an increasing incidence,pose a significant health *** there have been significant advances in the treatment of IBD,more progress is still *** oxygen therapy(HBOT)has been shown to treat a host of conditions such as carbon monoxide poisoning,decompression sickness,and gas *** the last few years,there has been an increase in research into the use of HBOT as an adjunct to conventional treatment for *** research has shown that HBOT may exert its therapeutic effects by decreasing oxidative stress,inhibiting mucosal inflammation,promoting ulcer healing,influencing gut microbes,and reducing the incidence of IBD *** paper aims to provide a comprehensive review of experimental and clinical trials exploring HBOT as a supplement to IBD treatment strategies.

关键词： hyperbaric oxygen therapy inflammatory bowel disease mucosal inflammation

Research progress in the study of atmospheric pressure glow barrier discharge

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Progress in Natural Science:Materials International 2007年第3期17卷 247-253页

作者： LI Xuechen, DONG Lifang and JIA Pengying (college of physics Science and technology, Hebei university, Baoding 071002, china) college of physics Science and technology Hebei University Baoding 071002 China

Atmospheric pressure glow barrier discharge (APGBD) can operate at high pressure, and so vacuum device is not necessary. Furthermore, the produced plasma by APGBD has moderate electron temperature and density besides good uniformity. Therefore, APGBD has extensive potential applications in industry and has been becoming a hot issue in the research of low temperature plasma. In this paper, the main problems in the study of atmospheric pressure glow discharge generated by dielectric barrier discharge, including the experimental setup, judging criterion, discharging conditions, physical mechanisms, and parameter diagnoses, are discussed, and further research prospects of APGBD are proposed.

关键词： atmospheric pressure glow discharge dielectric barrier discharge low temperature plasma.

Virtualities of quark and gluon in QCD vacuum

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Science china(physics,Mechanics & Astronomy) 2008年第10期51卷 1439-1447页

作者： ZHOU LiJuan1, QIN SongMei2, WU Qing3 & MA WeiXing4 1 Collaboration Group of Hadron physics and Non-perturbative QCD Study, guangxi university of Tech- nology, Liuzhou 545006, china 2 Department of physics, guangxi university, Nanning 540003, china 3 Department of physics, Qingdao university, Qingdao 266071, china 4 Institute of High Energy physics, Chinese Academy of Sciences, Beijing 100049, china Collaboration Group of Hadron physics and Non-perturbative QCD Study Guangxi University of Technology Liuzhou China Department of physics Guangxi University Nanning China Department of physics Qingdao University Qingdao China Institute of High Energy physics Chinese Academy of Sciences Beijing China

The non-local vacuum condensates of quantum chromodynamics (QCD) describe the distributions of quarks and gluons in the non-perturbative QCD vacuum state. Physically, this means that vacuum quarks and gluons have a nonzero mean-squared momentum in the vacuum, called virtuality. The quark virtuality is given by the ratio of the local quark-gluon mixed vacuum condensate to the quark local vacuum condensate. The gluon virtuality is expressed by gluon vacuum condensates and four-quark vacuum condensates. We study the two virtualities by solving Dyson-Schwinger Equations and calculating quark and gluon vacuum condensates. Our theoretical results for quark virtuality are in good agreement with many other theoretical model predictions such as QCD sum rules and lattice QCD calculations. Our calculation on gluon virtuality is initial and the results are quite interesting.

关键词： quark gluon virtuality QCD vacuum condensate non-perturbative QCD

Noether-Form Invariance of Nonholonomic Controllable Mechanical Systems in Phase Space

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Communications in Theoretical physics 2007年第7期48卷 23-26页

作者： XIA Li-Li LI Yuan-Cheng college of physics Science and technology,china university of Petroleum,Dongying 257061,china college of physics Science and technology China University of Petroleum Dongying 257061 China

In this paper,we study the Noether-form invariance of nonholonomic mechanical controllable systems inphase *** of motion of the controllable mechanical systems in phase space are *** definitionand the criterion for this system are presented.A new conserved quantity and the Noether conserved quantity deducedfrom the Noether-form invariance are *** example is given to illustrate the application of the results.

关键词： nonholonomic controllable mechanical system phase space Noether-form invariance conserved quantity

X-ray flares of γ-ray bursts: Quakes of solid quark stars?

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Science china(physics,Mechanics & Astronomy) 2009年第2期52卷 315-320页

作者： XU RenXin1 & LIANG EnWei2 1 School of physics and State Key Laboratory of Nuclear physics and technology, Peking university, Beijing 100871, china 2 Department of physics, guangxi university, Nanning 530004, china School of physics and State Key Laboratory of Nuclear physics and technology Peking University Beijing China Department of physics Guangxi University Nanning China

A star-quake model is proposed to understand X-ray flares of both long and short γ-ray bursts (GRBs) in a solid quark star regime. Two kinds of central engines for GRBs are available if pulsar-like stars are actually (solid) quark stars, i.e., the SNE-type GRBs and the SGR-type GRBs. It is found that a quark star could be solidified about 103 to 106 s later after its birth if the critical temperature of phase transi- tion is a few Metga-electron-volts, and then a new source of free energy (i.e., elastic and gravitational ones, rather than rotational or magnetic energy) could be possible to power GRB X-ray flares.

关键词： γ-rays bursts: X-rays neutron stars elementary particles