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Correlation of brain-derived neurotrophic factor to cognitive impairment following traumatic brain injury in rats

Neural Regeneration Research 2008年第11期3卷 1161-1167页

作者： dezhi Kang zhang Guo Department of Neurosurgery First Affiliated Hospital Fujian Medical University Fuzhou 350005 Fujian Province China

BACKGROUND： In vitro and in vivo studies have confirmed that brain-derived neurotrophic factor （BDNF） can promote survival and differentiation of cholinergic, dopaminergic and motor neurons, and axonal regeneration. BDNF has neuroprotective effects on the nervous system. OBJECTIVE： To explore changes in BDNF expression and cognitive function in rats after brain injury. DESIGN, TIME AND SETTING： The neuropathology experiment was performed at the Second Research Room, Department of Neurosurgery, Fujian Medical University （China） from July 2007 to July 2008. MATERIALS： A total of 72 healthy, male, Sprague Dawley, rats were selected for this study. METHODS： Rat models of mild and moderate traumatic brain injury were created by percussion, according to Feeney＇s method （n = 24, each group）. A bone window was made in rats from the sham operation group （n = 24）, but no attack was conducted. MAIN OUTCOME MEASURES： At days 1, 2, 4 and 7 following injury, BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was examined by immunohistochemistry （streptavidin-biotin-peroxidase complex method）. Changes in rat cognitive function were assessed by the walking test, balance-beam test and memory function detection. RESULTS： Cognitive impairment was aggravated at day 2, and recovered to normal at days 3 and 7 in rats from the mild and moderate traumatic brain injury groups. BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain was increased at 1 day, decreased at day 2, and then gradually increased in the mild and moderate traumatic brain injury groups. BDNF expression was greater in rats from the moderate traumatic brain injury group than in the sham operation and mild traumatic brain injury groups （P 〈 0.05）. CONCLUSION： BDNF expression in the rat frontal lobe cortex, hippocampus and basal forebrain is correlated to cognitive impairment after traumatic brain injury. BDNF has a protective effect on cognitive function in rats followi

关键词： brain-derived neurotrophic factor cognitive impairment traumatic brain injury

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Preparation and Interfacial Stability of SiC_f/Ti-6Al-4V Composites Fabricated Using Powder Coated Fiber Method

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Journal of Materials Science & Technology 2005年第6期21卷 903-908页

作者： Yanhua LI dezhi zhang Nanlin SHI Rui YANG Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China College of Environment and Chemical Engineering Dalian University Dalian 116622 China

SiCf/Ti-6Al-4V composites were fabricated by the powder-coated fiber method. The precursor fiber was prepared under the optimized parameter, and the composites were made using the vacuum hot pressure method. The influence of heat exposure time on products of thelinterfacial reaction was investigated using scanning electron microscope （SEM） and analytical transmission electron microscope （TEM） with energy dispersive spectrometer （EDS）. The main products are TiC and Ti5Si3 after vacuum exposing the samples at 700℃ for 50 h. The growth dynamics of interracial reaction products was analyzed quantitatively, which fitted the parabola rule. The activity energy of the reaction was 252 kJ·mol^-1.

关键词： Powder coated fiber SiCf/Ti-6Al-4V composites Interfacial reaction Kinetic Activity energy

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Interfacial Shear Strength Measurements of SiC Fiber-Reinforced Titanium Composites

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Journal of Materials Science & Technology 2005年第5期21卷 657-660页

作者： Yanhua LI Nanlin SHI dezhi zhang Rui YANG Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Collage of Environment and Chemical Engineering Dalian University Dalian 116622 China

A continuous loading push-out test technique was used to measure the interfacial shear strength of SiC fiber reinforced Ti matrix composites. The interfacial shear strength of samples as-fabricated and after heat exposed at 700 and 800℃ for 50 h was successfully determined. It has been found that the interfacial shear strength of the specimen exposed at 700℃ was higher than that of as-prepared and exposed samples at 800℃. The shear strength of the as-prepared samples was about 112.45 MPa, and increased to about 153.77 MPa after heat-treating at 700℃ for 50 h, but decreased to 133.11 MPa after treating at 800℃ for 50 h. Scanning electron microscope （SEM） was used to investigate the interfacial morphology of the samples. The brittle phase was the main products of interface for samples exposed at 800℃, and the interface was easily peeled off.

关键词： Push-out test SiCf/Ti composites Powder coated fiber Interracial shear strength

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Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

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Nuclear Science and Techniques 2024年第3期35卷 53-69页

作者： Ruibo Li Jin-Long Jiao Hui Luo dezhi zhang Dengwang Wang Kai Wang Graduate School of China Academy of Engineering Physics Beijing 100193China Zhejiang Institute of Modern Physics Institute of AstronomySchool of PhysicsZhejiang UniversityHangzhou 310027China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXi’an 710024China

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe *** reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant *** blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray ***,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex *** this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray *** significantly reduces the dependence of the numerical simulation on the grid *** reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

关键词： X-ray irradiation Energy deposition Blow-off impulse Particle in cells

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Kinking-facilitated nano-crystallization in a shock compressed Mg-1Zn alloy

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Journal of Magnesium and Alloys 2023年第4期11卷 1162-1169页

作者： Yuxuan Liu Yangxin Li Qingchun Zhu Huan zhang Xixi Qi Duofei Zheng Yunliang Li dezhi zhang Xiaoqin Zeng National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong University200240 ShanghaiChina Northwest Institute of Nuclear Technology Xi’anShanxi710024China

The local deformation behavior and dynamic recrystallization of a shock compressed Mg-1Zn alloy was investigated through EBSD and *** dislocation slipping and twinning were locally suppressed during high strain-rate deformation,a more flexible kinking deformation was activated to adjusted local orientation and facilitate slipping and twinning within the ***,due to the slow heat dissipation that resulted in a local temperature elevating,the kink bands were evolved into deformation bands with recrystallized *** a finding provides a new perspective for kinking-facilitated nanocrystallization in Mg alloys and other anisotropic metallic materials.

关键词： Magnesium alloys Kinking Twinning Dynamic recrystallization Nanocrystallization

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Distribution pattern and driving factors of genetic diversity of passerine birds in the Mountains of Southwest China

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Avian Research 2022年第3期13卷 249-255页

作者： Yongbin Chang Gang Song dezhi zhang Chenxi Jia Ping Fan Yan Hao Yanzhu Ji Fumin Lei Key Laboratory of Zoological Systematics and Evolution Institute of ZoologyChinese Academy of SciencesBeijing100101China University of Chinese Academy of Sciences Beijing100049China Center for Excellence in Animal Evolution and Genetics Chinese Academy of SciencesKunming650223China

Genetic diversity is one of the three dimensions of biodiversity and fundamental to various life forms on the *** the distribution pattern of genetic diversity and its driving forces has been an important topic in ecology,biogeography and conservation biology since the last *** investigated the genetic diversity pattern of passerine birds in the Mountains of Southwest China,a global biodiversity hotspot with the highest species richness of birds in the entire Eurasia,and explored the influencing forces of environmental variables on genetic *** compiled 1189 Cytochrome b sequences of 27 passerine species from 152 geographic sites,covering the range of Mountains of Southwest China and its adjoining *** generated genetic diversity distribution maps using a grid-cell method based on nucleotide diversity and haplotype diversity *** further analyzed the variation pattern of the two indices along latitudinal,longitudinal,and elevational *** correlations between the two indices and environmental variables were also *** nucleotide diversity hotspots were mostly located in the southern Hengduan Mountains,while for haplotype diversity,three hotspots were detected:the southeast edge of the Qinghai-Tibetan Plateau,the southern Hengduan Mountains and the Qinling *** was no monotonic increasing or decreasing pattern in nucleotide diversity or haplotype diversity along latitudinal,longitudinal or elevational gradients except for altitudinal *** and model selection analyses detected multiple environmental variables in driving genetic diversity patterns,including temperature,precipitation,vegetation,human influence,longitude and altitude *** to the pattern of species richness,the nucleotide diversity pattern of passerine birds in the Mountains of Southwest China presents a decreasing trend from southwest to northeast,while the haplotype diversity pattern is more likely decreased from we

关键词： Environmental variables Genetic diversity pattern Mountains of Southwest China Passerine birds

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Microstructural Changes of T1-6A1-4V Matrix by the Incorporation of Continuous SiC Fibers

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Journal of Materials Science & Technology 2006年第4期22卷 452-454页

作者： Yuechun FU Nanlin SHI dezhi zhang Rui YANG Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

In SiC（f）/Ti-6Al-4V composites, the microstructure of the matrix close to the fiber was different from that of the fiber-less material. Microstructure observations show that a layer of fine grains was located adjacent to the fiber, and more dislocations and faults were found in this region. Higher recrystallization nucleation rate due to the undeformed SiC fiber and thermal residual stress induced during cooling from the fabrication temperature caused the microstructural changes of the matrix. Hardness measurement indicates that the matrix in the fiber neighborhood was strengthened, and the strengthening effect decreased with distance away from the fiber.

关键词： Matrix strengthening Ti-6Al-4V powder SiC fiber Metal-matrix composites

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卫星扩频应答机的伪码快捕方法

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北京航空航天大学学报 2010年第9期36卷 1017-1020,1025页

作者：冯文全张德智北京航空航天大学电子信息工程学院北京100191

在低地球轨道通信系统中,由于系统的高动态,使扩频应答机接收的信号附加了几十千赫兹的多普勒频移,传统的伪码捕获方法很难完成捕获.对此提出了一种部分相关和FFT(Fast Fourier Transform)相结合的捕获方法,利用FFT补偿多普勒造成的相... 详细信息

在低地球轨道通信系统中,由于系统的高动态,使扩频应答机接收的信号附加了几十千赫兹的多普勒频移,传统的伪码捕获方法很难完成捕获.对此提出了一种部分相关和FFT(Fast Fourier Transform)相结合的捕获方法,利用FFT补偿多普勒造成的相关峰损失,在搜索码相位的同时得到多普勒频移的估计,减少了捕获时间.给出了捕获系统的结构,分析了FFT对相关峰的补偿性能,给出了部分相关和FFT的参数设计方法,使用了自适应门限技术,以满足输入信号载噪比大幅变化的情况下实现伪码的捕获判决.理论分析和仿真结果表明:该方法可以在高多普勒频移和低载噪比环境下实现伪码的快速捕获,比其他快捕方法占用更少的FPGA(Field Programmable Gate Arrays)资源.

关键词：扩频通信应答机多普勒影响快速傅里叶变换

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论原始宗教信仰中体育元素的表达——以萨满教为例

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体育与科学 2013年第2期34卷 38-41页

作者：张德智西安建筑科技大学体育系

对萨满教祭祀仪式中体育元素的表达进行研究,认为部分少数民族体育的起源与原始宗教活动有着密切的关系,萨满教中的祭祀仪式孕育了宗教体育活动的产生,萨满教信仰进一步促进了祭祀体育活动的完善和发展;宗教仪式中的体育活动体现了浓郁... 详细信息

对萨满教祭祀仪式中体育元素的表达进行研究,认为部分少数民族体育的起源与原始宗教活动有着密切的关系,萨满教中的祭祀仪式孕育了宗教体育活动的产生,萨满教信仰进一步促进了祭祀体育活动的完善和发展;宗教仪式中的体育活动体现了浓郁的原始宗教色彩;祖先崇拜,自然崇拜,图腾崇拜以及禳祓、脱灾、祈福仪式是少数民族体育元素表达的重要载体;渔猎文明与神话传说在凝聚族群意识的同时也促进了少数民族传统体育的价值认同。

关键词：原始宗教萨满图腾崇拜祖先崇拜自然崇拜宗教仪式体育

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Fe_3Al基合金力学性能的各向异性研究

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钢铁 1998年第11期33卷 54-56页

作者：张德志职任涛肖纪美北京科技大学

研究了Ｆｅ３Ａｌ基合金抗拉性能与拉伸取向的关系。结果表明，各向异性明显，沿轧向的伸长率明显高于其它取向。

关键词： Fe3Al 力学性能各向异性伸长率

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