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BIFURCATION AND SPATIOTEMPORAL PATTERNS IN A HOMOGENEOUS DIFFUSION-COMPETITION SYSTEM WITH DELAYS

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International Journal of Biomathematics 2012年第6期5卷 19-41页

作者： JIA-fang ZHANG WAN-TONG LI XIANG-PING YAN School of Mathematics and Information Sciences Henan University Kaifeng Henan 575001 P. R. China School of Mathematics and StatisticsLanzhou University Lanzhou Gansu 730000 P. R. China Department of MathematicsLanzhou Jiaotong University Lanzhou Gansu 730070 P. R. China

A competitive LotkaVolterra reactiondiffusion system with two delays subject to Neumann boundary conditions is considered. It is well known that the positive con stant steady state of the system is globally asymptotically stable if the interspecies competition is weaker than the intraspecies one and is unstable if the interspecies com petition dominates over the intraspecies one. If the latter holds, then we show that Hopf bifurcation can occur as the parameters （delays） in the system cross some critical val ues. In particular, we prove that these Hopf bifurcations are all spatially homogeneous if the diffusive rates are suitably large, which has the same properties as Hopf bifur cation of the corresponding delayed system without diffusion. However, if the diffusive rates are suitably small, then the system generates the spatially nonhomogeneous Hopf bifurcation. Furthermore, we derive conditions for determining the direction of spatially nonhomogeneous Hopf bifurcations and the stability of bifurcating periodic solutions. These results indicate that the diffusion plays an important role for deriving the complex spatiotemporal dynamics.

关键词： LotKa-Volterra competition system time delay spatial diffusion Hopf bifur-cation periodic solution.

Preparation of Chitosan-based Microspheres for Rapid Hemostasis

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Paper And Biomaterials 2021年第1期6卷 41-49页

作者： Yan fang Peiyuan Li Weikang Zhou Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials ScienceFujian Normal UniversityFuzhouFujian Province350007China

Rapid control of heavy hemorrhaging is critical to save the life of injured ***,we developed a novel hemostat employing chitosan-based microspheres,which was prepared by sequential microemulsion of chitosan solution,sol-gel phase transition,and surface modification by 3,4-dihydroxyhydrocinnamic acid(HCA).HCA-modified chitosan microspheres(CSMS-HCA)displayed a porous structure,with a high specific surface area(~211.3 m^(2)/g),accelerating their rapid absorption of blood and concentrating red cells and *** CSMS-HCA exhibited much better in vitro and in vivo hemostatic efficacy than porous chitosan microspheres *** a rapid hemostat in the form of microspheres is highly effective in treating deep and irregular wounds,owing to easy accessibility to injured sites.

关键词： chitosan microspheres hemostasis wet-tissue adhesion

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Probiotics for preventing gestational diabetes in overweight or obese pregnant women:A review

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World Journal of Clinical Cases 2022年第36期10卷 13189-13199页

作者： Ya-fang Deng Li-Ping Wu Yan-Ping Liu Chinese Academy of Medical Sciences and Peking Union Medical College School of NursingBeijing 100730China Department of Clinical Nutrition Chinese Academy of Medical Sciences and Peking Union Medical College HospitalBeijing 100730China

Probiotics are live microorganisms that,when administered in adequate amounts,confer a health benefit to the *** probiotics or probiotic foods can be used to reduce the risk of diseases associated with aberrant gut microbiota *** incidence of gestational diabetes mellitus(GDM)has increased annually with the proportion of overweight and obese *** or obese pregnant women are at high risk of GDM and have obvious changes in gut microbiota compared with normal-weight pregnant *** probiotics or probiotic foods may alter gut microbiota in overweight or obese pregnant women and inhibit the expression of inflammatory factors,consequently resulting in weight loss and reduced insulin *** review discusses the mechanism of probiotics on GDM,as well as the dose,method and duration of probiotics use,and summarizes current evidence on probiotics in improving glucose metabolism and other maternal and infant outcomes in overweight/obese pregnant women.

关键词： Probiotics Gut microbiota Diabetes Gestational Overweight Obesity Maternal

A Unified Symmetry of Mechanical Systems with Variable Mass in Phase Space

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Communications in Theoretical Physics 2006年第3X期46卷 385-388页

作者： WANG Peng fang Jian-Hui ZHANG Peng-Yu, DING Ning College of Physics and Technology China University of Petroleum Dongying 257061 China

In this paper, the definition and the criterion of a unified symmetry of the mechanical system with variable mass in phase space are given. The Noether conserved quantity, the generalized Hojman conserved quantity, and Mei conserved quantity deduced from the unified symmetry are obtained. An example is given to illustrate the application of the results.

关键词： phase space variable mass system unified symmetry conserved quantity

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Corporate Endowment Insurance Fee Reduction and Employee Wages:Evidence from China

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China & World Economy 2023年第2期31卷 192-222页

作者： Xufei Zhang Hongsheng fang Lin Guo School of Economics Zhejiang UniversityChina School of Management Weifang Medical UniversityChina

To stimulate economic growth,the Chinese government implemented three consecutive policies between 2016 and 2019 to reduce the corporate endowment insurance contribution ratio(CEICR),the highest payment item for Chinese *** China's CEICR reduction policies as a quasi-natural experiment,this paper evaluates the impact of corporate payment burden reduction on employee ***,reducing CEICR appears to prompt companies to increase employee *** cash flow is a possible channel of ***,the positive effect is found to be more pronounced in companies that are more labor intensive,performing better in labor payment compliance,and located in regions with higher pressure for elderly *** paper offers evidence in favor of implementing CEICR reduction policies from the perspective of improving the well-being of employees.

关键词： corporate endowment insurance contribution ratio corporate endowmen insurance fee employee wages fee reduction policies

Beam Measurement System in NSRL

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Journal of Systems Engineering and Electronics 2000年第3期11卷 9-13页

作者： Sun, Baogen Lu, Ping Wang, Junhua fang, Zhigao Liu, Jianhong Univ of Science and Technology of China Hefei China

This paper describes the beam measurement system for the accelerator of the National Synchrotron Radiation Laboratory (NSRL). The design considerations of the beam measurement instrumentation system for the NSRL are aided by the commissioning of the machine and provide sufficient machine parameters for machine study as well as the common operation. The beam measurement system includes the part for the linac and transport line and the part for the storage ring. The measurement results are presented in the paper.

关键词： Fluorescent screens Parameter estimation Synchrotron radiation Transport properties

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Changes of corneal central thickness of aphakia following congenital cataract surgery under the first six months of life

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International Journal of Ophthalmology(English edition) 2011年第1期4卷 78-80页

作者： Wei Xiao Xiao-fang Liang and Jia-Jun Sun Department of Ophthalmology Shengjing Hospital of China Medical University Shenyang 110004 Liaoning Province China

AIM: To observe the central corneal thickness (CCT) changes in infants and young children who had been undergone bilateral congenital cataract surgery, and to compare the changes with normal control group which was selected from healthy population. METHODS: A cross section case-control study contained 28 cases (56 eyes) of bilateral aphakia (aphakic group) due to congenital cataract surgery combining with posterior continuous curvilinear capsulorhexis and with anterior vitrectomy during 2-6 months after birth. Fourteen children (28 eyes) of age-sex matched with the aphalic group were selected as normal control group. CCT and intraocular pressure (TOP) were measured postoperatively and the results were compared between groups. RESULTS: The mean CCT was 653.5 +/- 82.4 mu m in the aphakic group and 579.6 +/- 39.2 mu m in the control group, with a significant difference (P=0.000). The mean value of TOP in aphakic group (22.0 +/- 1.6mmHg) was greater than that of control group (16.9 +/- 2.1mmHg), P=0.023. There was a negative correlation between age and CCT in normal control group (r=-0.531, P=0.026), and there was no correlation in bilateral aphakia group (r=-0.324, P=0.165). CONCLUSION: Aphakic children due to congenital cataract surgery have a greater CCT than normal children. It is necessary to consider CCT in evaluating IOP for children after congenital cataract surgery.

关键词： congenital cataract surgery aphaka central corneal thickness introcular pressure

Effects of Ce,Y,and Sm doping on the thermoelectric properties of Bi2Te3 alloy

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Progress in Natural Science:Materials International 2013年第4期23卷 408-412页

作者： fang Wu Hongzhang Song Jianfeng Jia Xing Hu School of Physical Engineering Zhengzhou University Department of Physics Henan Institute of Education

Nanopowders of elements doped Bi2Te3thermoelectric alloy R0.2Bi1.8Te3(R Ce,Y and Sm)were synthesized by the hydrothermal *** nanopowders were hot-pressed into pellets and their thermoelectric properties were *** results show that Ce,Y,and Sm doping has signifcant effects on the morphologies of the synthesized nanopowders and thermoelectric *** the doping elements,Ce doping is a superiority *** the electrical conductivity and Seebeck coeffcient are not improved much by Ce doping,the thermal conductivity is supressed *** a result the fgure of merit(ZT) of Ce0.2Bi1.8Te3is improved and reaches 1.29 at 398 K,which is higher than the Bi2Te3ingots made by the traditional zone-melting method

关键词： Elements doped R0.2Bi1.8Te3 Morphologies Figure of merit

Treatment of portal vein tumor thrombus using ^(125)Iodine seed implantation brachytherapy

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World Journal of Gastroenterology 2010年第38期16卷 4876-4879页

作者： Lin Zhang Wei Mu Cun-fang Hu Xue-Quan Huang Department of Interventional Radiology Southwest Hospital Third Military Medical University Chongqing 400038China

We reported two cases of liver metastasis with portal vein tumor thrombus that developed after liver transplantation for hepato cellular carcinoma (HCC). Both the patients were women aged 43 and 55 years, who had live... 详细信息

关键词： Computed tomography-guided