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Two New Types of Conserved Quantities of Mei Symmetry for Holonomic Mechanical System

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Communications in Theoretical Physics 2008年第1期49卷 53-56页

作者： FANG jian-hui WANG Peng DING ning College of Physics Science and Technology China University of Petroleum Dongying 257061 China

Two new types of conserved quantities directly deduced by Mei symmetry of holonomic mechanical system are studied. The definition and criterion of Mei symmetry for holonomic system are given. A coordination function is introduced, the conditions under which the Mei symmetry can directly lead to the two types of conserved quantities and the forms of the two types of conserved quantities are obtained. An illustrative example is given. The result indicates that the coordination function can be selected properly according to the demand of the gauge function, thereby the gauge function can be found out more easily. Furthermore, since the choice of the coordination function has multiformity, much T more conserved quantity of Mei symmetry for holonomic mechanical system can be obtained.

关键词： holonomic mechanical system Mei symmetry new conserved quantity

Perturbation and Adiabatic Invariants of Mei Symmetry for Nonholonomic Mechanical Systems

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Communications in Theoretical Physics 2007年第4期47卷 594-596页

作者： DING ning FANG jian-hui WANG Peng College of Physical Science and Technology China University of Petroleum Dongying 257061 China

Based on the concept of adiabatic invariant, the perturbation and adiabatic invariants of the Mei symmetry for nonholonomic mechanical systems are studied. The exact invariants of the Mei symmetry for the system without perturbation are given. The perturbation to the Mei symmetry is discussed and the adiabatic invariants of the Mei symmetry for the perturbed system are obtained.

关键词： Mei symmetry perturbation adiabatic invariant nonholonomic mechanical system

Precise Evolutionary Asteroseismology of High-AmplitudeδScuti Star AE Ursae Majoris

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Research in Astronomy and Astrophysics 2022年第10期22卷 61-76页

作者： hui-Fang Xue Jia-Shu Niu jian-ning Fu Department of Physics Taiyuan Normal UniversityJinzhong 030619China Institute of Computational and Applied Physics Taiyuan Normal UniversityJinzhong 030619China Institute of Theoretical Physics Shanxi UniversityTaiyuan 030006China State Key Laboratory of Quantum Optics and Quantum Optics Devices Shanxi UniversityTaiyuan 030006China Department of Astronomy Beijing Normal UniversityBeijing 100875China

Stellar structure and evolution theory is one of the bases in modern *** inner structures and their evolutionary states can be precisely tested by asteroseismology,since the inner information is brought to the stellar surface by the global oscillating waves and becomes *** stellar evolutionary speed(i.e.,how long timescale does a star stay at a special evolution phase?),because of the insurmountable gap between the timescales of the evolutionary history of human civilization and a star,it can only be roughly tested by ensemble of stars in different evolutionary stages in most cases,and all the snapshots of these stars make up our global view of stellar *** effect of stellar evolution on the structure and the corresponding global size of a pulsating star will lead to tiny period variations of its pulsation modes,which are the most valuable indicators of its evolutionary state and can be used to test the stellar evolution theory by a single star rather than ensemble of ***,we report a High-AmplitudeδScuti star AE Ursae Majoris,which is located in the post main-sequence(MS)evolutionary stage and its observed linear period variation rate can be practically ascribed to its evolutionary *** result tests the stellar evolution theory from the pre-MS to post-MS with an unprecedented precision by a single star,and the framework can be extended to other type of pulsating stars to perform precise evolutionary asteroseismology,which aims to test the current stellar evolution theory in different evolutionary stages,discover the discrepancies between the theory and observations,and ultimately build a complete and precise stellar evolution theory to backtrack the history of each of these stars.

关键词： stars variables delta Scuti-stars evolution-stars oscillations(including pulsations)

Prevalence of Helicobacter pylori infection in Chinese military personnel:A cross-sectional,multicenter-based study

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World Journal of Gastroenterology 2025年第3期31卷 42-49页

作者： Han-Chen Min Chun-Yan Zhang Fang-Yu Wang Xiao-hui Yu Shan-Hong Tang Hong-Wu Zhu Ya-Gang Zhao Ji-Luo Liu jian Wang Jing-Han Guo Xiao-Mei Zhang Yun-Sheng Yang Chinese People’s Liberation Army Medical School Chinese People’s Liberation Army General HospitalBeijing 100853China Department of Gastroenterology and Hepatology The First Medical CenterChinese People’s Liberation Army General HospitalBeijing 100853China Sixth Healthcare Department The Second Medical CenterChinese People’s Liberation Army General HospitalBeijing 100853China Department of Gastroenterology The 940th Hospital of Joint Logistic Support Force of Chinese People’s Liberation ArmyLanzhou 730050Gansu ProvinceChina Department of Gastroenterology General Hospital of Western Theater CommandChengdu 610011Sichuan ProvinceChina Department of Gastroenterology General Hospital of Southern Theater CommandGuangzhou 510010Guangdong ProvinceChina Department of Epidemiology Naval Medical UniversityShanghai 200433China School of Medicine Nankai UniversityTianjin 300071China National Clinical Research Center for Geriatric Diseases Chinese People’s Liberation Army General HospitalBeijing 100853China

BACKGROUND Helicobacter pylori(***)infection is a prevalent disease encountered in military internal medicine and recognized as the main cause of dyspepsia,gastritis,and peptic ulcer,which are common diseases in military *** guidelines in China state all patients with evidence of active infection with *** are offered ***,the prevalence of *** infection and its regional distribution in the military population remain unclear,which hinders effective prevention and treatment *** the prevalence of *** infection in the military population will aid in the development of customized strategies to better manage this infectious *** To investigate the prevalence of *** infection in the Chinese military population in different geographic *** This multicenter,retrospective study included 22421 individuals from five tertiary hospitals located in north,east,southwest,and northwest cities of *** infection was identified using the urea breath test,which had been performed between January 2020 and December *** Of the 22421 military service members,7416(33.1%)were urea breath *** highest prevalence of *** was in the 30-39 years age group for military personnel,with an infection rate of 34.9%.The majority of infected subjects were younger than 40-years-old,accounting for 70.4%of the infected *** individuals serviced in Lanzhou and Chengdu showed a higher infection prevalence than those in Beijing,Nanjing,and Guangzhou,with prevalence rates of 44.3%,37.9%,29.0%,31.1%,and 32.3%,*** *** infection remains a common infectious disease among military personnel in China and has a relatively high prevalence rate in northwest China.

关键词： Helicobacter pylori Prevalence Military personnel Urea breath test Multicenter study

Effects of SiO_(2) on the preparation and metallurgical properties of acid oxidized pellets

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 629-636页

作者： jian-guang Lu Chen-chen Lan Qing Lyu Shu-hui Zhang jian-ning Sun School of Metallurgy Northeastern UniversityShenyang 110819China College of Metallurgy and Energy North China University of Science and TechnologyTangshan 063009China HBIS Group Hansteel Company Handan 05600China

The effects of SiO_(2) content on the preparation process and metallurgical properties of acid oxidized pellets, including compressive strength, reduction, and softening–melting behaviors, were systematically *** structures, elemental distribution, and pore size distribution were varied to analyze the mechanism of the *** results show that with an increase in SiO_(2) content from 3.51 wt%to 7.18 wt%, compressive strength decreases from 3150 N/pellet to 2100 N/pellet and reducibility decreases from 76.5% to 71.4%.The microstructure showed that pellets with high SiO_(2) content contained more magnetite in the mineralogical ***, some liquid phases appeared, which hindered the continuous crystallization of ***, the softening–melting properties of the pellets clearly deteriorated as the SiO_(2) content *** increasing SiO_(2) content, the temperature range of the softening–melting zone decreased, and the maximum differential pressure and the comprehensive permeability index increased *** acid oxidized pellets are used as the raw materials for blast furnace smelting, it should be combined with high basicity sinters to improve the softening–melting behaviors of the comprehensive charge.

关键词： acid oxidized pellets SiO_(2)content metallurgical property mineralogical structure

Hydrodynamic performance of flexible risers subject to vortex-induced vibrations

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Journal of Hydrodynamics 2013年第1期25卷 156-164页

作者： ZHANG hui YANG jian-min XIAO Long-fei LU Hai-ning State Key Laboratory of Ocean Engineering Shanghai Jiaotong University

The Vortex-Induced Vibration （VIV） displacements are determined from both the measured accelerations and strains in a series of VIV experiments. Based on the results, the forces in the longitudinal, transversal and tangential directions are estimated by using the finite element method with and without considering the interactions between adjacent elements. The numerical simulation indicates that the method considering the interactions performs better in the estimation of the forces. The component of the transversal force in phase with the acceleration is associated with the added mass coefficient. The estimated added mass coefficients take abnormally high values at the locations where the displacements are small. An improved formula based on the L＇Hospital＇s rule is pro- posed to deal with this problem. The results show the advantage of this formula in estimating the added mass coefficients at the loca- tions with small VIV displacements.

关键词： Vortex-Induced Vibration (VIV) flexible risers hydrodynamic force added mass coefficient

Modulating conductivity type of cuprous oxide（Cu2O） films on copper foil in aqueous solution by comproportionation

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Journal of Materials Science & Technology 2019年第8期35卷 1570-1577页

作者： Changwei Tang Xiaohui ning jian Li hui-Lin Guo Ying Yang Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of EducationCollege of Chemistry & Materials ScienceNorthwest UniversityXi'an 710127 China National Demonstration Center for Experimental Chemistry Education Northwest UniversityXi'an 710127 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049 China

Cuprous oxide(Cu2O)is an attractive material for photoelectrochemical(PEC)hydrogen production or photovoltaic application,because of its appropriate band gap,low material cost and *** this paper,Cu2O films were obtained by comproportionation in acid cupric sulfate solutions with varying concentrations of potassium *** and electrochemical experiments,such as zero-bias photocurrent responses,voltammograms,and Mott-Schottky measurements,show that the Cu2O films grown in low(≤0.75 mol dm^–3)and high(≥1.00 mol dm^–3)nitrate ion concentrations presented n-type and p-type conductivity,*** circuit potential and polarization behavior were monitored to investigate the mechanism of modulating conductivity *** ions consume protons in the plating solution during comproportionation with different concentrations of nitrate ions creating different pH at the Cu2O/solution *** gradient leads to the transformation of Cu2Ofilms conductivity changing from n-type to p-type with increasing the concentration of nitrate ions in the plating *** method could be used to fabricate homojunction electrode on metal substrate for PEC hydrogen production or photoelectric application.

关键词： Cuprous oxide(Cu2O) Comproportionation Semiconductor films Tuning conductivity Photoelectrochemical cell

A local pseudo arc-length method for hyperbolic conservation laws

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Acta Mechanica Sinica 2014年第6期30卷 956-965页

作者： Xing Wang Tian-Bao Ma hui-Lan Ren jian-Guo ning State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology

A local pseudo arc-length method（LPALM）for solving hyperbolic conservation laws is presented in this *** key idea of this method comes from the original arc-length method,through which the critical points are bypassed by transforming the computational *** method is based on local changes of physical variables to choose the discontinuous stencil and introduce the pseudo arc-length parameter,and then transform the governing equations from physical space to arc-length *** order to solve these equations in arc-length coordinate,it is necessary to combine the velocity of mesh points in the moving mesh method,and then convert the physical variable in arclength space back to physical *** examples have proved the effectiveness and generality of the new approach for linear equation,nonlinear equation and system of equations with discontinuous initial ***-oscillation solution can be obtained by adjusting the parameter and the mesh refinement number for problems containing both shock and rarefaction waves.

关键词： Numerical method Local pseudo arc-length method Hyperbolic conservation laws Mesh adaptation

Hole transport and phonon scattering in epitaxial PbSe films

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 137-142页

作者： jian-xiao SI hui-zhen WU Tian-ning XU Chun-fang CAO Department of Physics Zhejiang University Hangzhou 310027 China College of Physics and Mathematics Zhejiang Normal University Jinhua 321004 China

The combined characterizations of mobility and phonon scattering spectra allow us to probe hole transport process in epitaxial PbSe crystalline films grown by molecular beam epitaxy (MBE). The measurements of Hall effect show p-type con- ductivity of PbSe epitaxial films. At 295 K, the PbSe samples display hole concentrations of (5～8)×1017 cm–3 with mobilities of about 300 cm2/(V·s), and at 77 K the hole mobility is as high as 3×103 cm2/(V·s). Five scattering mechanisms limiting hole mobilities are theoretically analyzed. The calculations and Raman scattering measurements show that, in the temperatures between 200 and 295 K, the scattering of polar optical phonon modes dominates the impact on the observed hole mobility in the epitaxial PbSe films. Raman spectra characterization observed strong optical phonon scatterings at high temperature in the PbSe epitaxial films, which is consistent with the result of the measured hole mobility.

关键词： Electrical properties of PbSe Mobility Scattering mechanism