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跳频系统中电荷泵锁相环的事件驱动仿真

系统工程与电子技术 2003年第8期25卷 925-927,945页

作者：苏彦锋王涛衣晓峰洪志良复旦大学微电子学系上海200433

为了快速仿真单片集成跳频系统中的电荷泵锁相环 ,在比较几种常见仿真方法的基础上 ,重点介绍了电荷泵锁相环的事件驱动模型 ,并针对这种模型的具体实现提出了一些改进。改进后的模型主要应用于跳频系统中频率合成锁相环的稳定性和建立... 详细信息

为了快速仿真单片集成跳频系统中的电荷泵锁相环 ,在比较几种常见仿真方法的基础上 ,重点介绍了电荷泵锁相环的事件驱动模型 ,并针对这种模型的具体实现提出了一些改进。改进后的模型主要应用于跳频系统中频率合成锁相环的稳定性和建立时间的快速仿真。

关键词：电荷泵锁相环跳频系统事件驱动行为级仿真

Effects of Bifidobacterium lactis BLa80 on fecal and mucosal flora and stem cell factor/c-kit signaling pathway in simulated microgravity rats

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World Journal of Gastroenterology 2025年第1期31卷 93-109页

作者： Ping Zhang ying Zhu Pu Chen Tong Zhou Zhe-yi Han Jun xiao Jian-feng Ma Wen Ma Peng Zang ying Chen Graduate School Hebei North UniversityZhangjiakou 075000Hebei ProvinceChina Key Laboratory of Aerospace Nutrition and Food Engineering China Astronaut Research and Training CenterBeijing 100094China Department of Gastroenterology The Air Force Medical CenterBeijing 100142China Department of Blood Transfusion Air Force Medical CenterBeijing 100142China

BACKGROUND Simulated microgravity environment can lead to gastrointestinal motility *** pathogenesis of gastrointestinal motility disorders is closely related to the stem cell factor(SCF)/c-kit signaling pathway associated with intestinal flora and Cajal stromal ***,intestinal flora can also affect the regulation of SCF/c-kit signaling pathway,thus affecting the expression of Cajal stromal *** cells are the pacemakers of gastrointestinal *** To investigate the effects of Bifidobacterium lactis(***)BLa80 on the intestinal flora of rats in simulated microgravity and on the gastrointestinal motility-related SCF/c-kit *** The internationally recognized tail suspension animal model was used to simulate the microgravity environment,and 30 rats were randomly divided into control group,tail suspension group and drug administration tail suspension group with 10 rats in each group for a total of 28 *** tail group was given *** BLa80 by intragastric administration,and the other two groups were given water intragastric administration,the concentration of intragastric administration was 0.1 g/mL,and each rat was 1 mL/***&eosin staining was used to observe the histopathological changes in each segment of the intestine of each group,and the expression levels of SCF,c-kit,extracellular signal-regulated kinase(ERK)and p-ERK in the gastric antrum of each group were detected by Western blotting and *** fecal flora and mucosal flora of rats in each group were detected by 16S *** Simulated microgravity resulted in severe exfoliation of villi of duodenum,jejunum and ileum in rats,marked damage,increased space between villi,loose arrangement,shortened columnar epithelium of colon,less folds,narrower mucosal thickness,reduced goblet cell number and crypts,and significant improvement after probiotic *** microgravity reduced the expressions of SCF and c-kit,and increased the express

关键词： Simulated microgravity Rat Intestinal flora Gastrointestinal motility Stem cell factor/c-kit signaling pathway

Oxidation behavior of in-situ Al_2O_3/TiAl composites at 900°C in static air

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 339-344页

作者： tao-tao Ai Fen wang xiao-ming feng Department of Materials Science and Engineering Shaanxi University of Technology Hanzhong 723003 China School of Materials Science and Engineering Shaanxi University of Science and Technology Xi＇an 710021 China

In-situ Al2O3/TiAl composites were successfully synthesized from the starting powders of Ti, Al, TiO2 and Nb2O5. The oxidation behavior of the composites at 900℃ in static air was investigated. The results indicate that the composite samples present a much lower oxidation mass gain. Under long-time intensive oxidation exposure, the formed oxide scale is multi-layer. The formation of the outer TiO2 layer is fine and dense, the internal Al2O3 scale has good adhesiveness with the outer TiO2 scale, and the TiO2＋Al2O3 mixed layer forming the protective oxide scale is favorable for the improvement of oxidation resistance. It is believed that the incorporation of Al2O3 particulates into the metal matrix decreases the coefficient of thermal expansion of the substrate, and forms a local three-dimensional network structure that can hold the oxide scale. The formation of the oxide scale with finer particle size, stronger adherence, less micro-defects and slower growth rate can contribute to the improvement of oxidation resistance. Nb element plays an important role in reducing the internal oxidation action of the materials, restraining the growth of TiO2 crystals and promoting the stable formation of the Al2O3-riched layer, which is beneficial to improve the oxidation properties.

关键词： intermetallic matrix composites alumina oxidation resistance scale spallation high temperature

Theoretical calculation and experimental study on the interaction mechanism between TKX-50 and AP

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Defence Technology（防务技术） 2020年第4期16卷 825-833页

作者： Jun tao xiao-feng wang Kun Zhang Xue-song feng The Second Department Xi'an Modern Chemistry Research InstituteXi'an 710065China

The combination of 5,5'-bistetrazole-1,1'-diolate(TKX-50) and ammonium perchlorate(AP) can make greater use of the chemical energy of TKX-50 based energetic *** research on the interaction mechanism between TKX-50 and AP is very important for designing TKX-50-AP compounds and judging the formation feasibility of composite particles,which can lay a theoretical foundation for the preparation of TKX-50-AP mixed crystals and the application of TKX-50 in propellant,propellant and ***,in order to research the interaction mechanism between TKX-50 and AP,density-functional theory calculation was applied to optimize three configurations of TKX-50-AP *** geometry structure,electrostatic potential and binding energy of the compounds were predicted,and the electronic density topological analysis was also carried *** TKX-50-AP mixed crystals structures were constructed,and the radial distribution function of H-O and H-N in mixed crystals was ***,solvent/non-solvent method was applied to prepare TKX-50-AP composites,and the infrared spectro scopy and the non-isothermal decomposition perfo rmance of the composites were *** show that the superposition of positive charges in TKX-50 molecule and negative charges in AP makes the electrostatic potential distributions of TKX-50-AP compounds different from that of TKX-50 and *** interaction energies of TKX-50-AP 1,TKX-50-AP 2 and TKX-50-AP 3 are 39.743 kJ/mol,61.206 kJ/mol and 27.702 kJ/mol,*** interaction between TKX-50 molecules and AP molecules in TKX-50-AP mixed crystals both depends on hydrogen bonds and van der Waals force,and the number and strength of hydrogen bonds are significantly greater than that of van der Waals *** composition of AP and TKX-50 makes the absorption peak of the five-membered rings and NH_3 OH^+ of TKX-50 shift to low wavenumber in the infrared *** general,TKX-50 interacts with AP via hydrogen bonds and va

关键词： 5,5'-bistetrazole-1,1'-diolate Ammonium perchlorate Density-functional theory Molecular dynamics Hydrogen bond

Recyclable Polyurea-Urethane Thermosets with De-Crosslinking Capability in Acetic Acid

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Chinese Journal of Polymer Science 2023年第6期41卷 859-865,I0006页

作者： Xinglei tao Wentian yi xiao-Qi Xu Yapei wang Key Laboratory of Advanced Light Conversion Materials and Biophotonics Department of ChemistryRenmin University of ChinaBejing 100872China

Covalent crosslinking points within thermosets generally result in excellent mechanical properties and solvent resistance yet lead to limited degradability and *** thermosets become degradable or recyclable if crosslinking points are cleavable or *** this principle,we report a kind of polyurea-urethane thermoset with borate ester as its crosslinking point to enable a controllable decrosslinking in response to acetate *** a thermoset presents remarkable mechanical properties as well as outstanding solvent resistance capability,due to the high crosslinking density and intermolecular hydrogen ***,the de-crosslinked product can be reporcessed to generate a brand new thermoplastic material.

关键词： material. crosslinking reversible

Improving the stability,lithium diffusion dynamics,and specific capacity of SrLi_(2)Ti_(6)O_(14)via ZrO_(2)coating

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Green Energy & Environment 2022年第1期7卷 53-65页

作者： Hong-Li Ding Hai-tao Yu xiao-dong wang Chen-feng Guo Bing Zheng ying Xie Ting-feng yi Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin150080China College of Material Science and Chemical Engineering Harbin Engineering UniversityHarbin150001China School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao066004China Institute of Advanced Electrochemical Energy&School of Materials Science and Engineering Xi'an University of TechnologyXi'anShaanxi710048China

SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully *** as-obtained composites are stacked by a series of particles with a pure phase structure and a good ***,ZrO_(2)coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI *** a result,the redox polarization was reduced,and the reversibility of the electrochemical reaction was ***,SLTO-ZrO_(2)-2 sample delivers a high initial lithiation capacity of 283.6 mA h g^(-1),and the values maintain at 251.7,228.0,207.4,175.3,and 147.7 mA h g^(-1)at the current densities of 0.13,0.26,0.54,1.31,and 2.62 A g^(-1),*** experiment also confirmed that SLTO materials coated with ZrO_(2)are suitable for high power density applications,and the lithiation specific energy efficiency of SLTO-ZrO_(2)-2 is 200%as high as that of pure SLTO at a power density of 1257 W kg^(-1).

关键词： SrLi_(2)Ti_(6)O_(14) ZrO_(2)coating Structural stability Anode material Electrochemical performance

Analysis of the anti-T2DM components in dichloromethane fraction of Schisandra sphenanthera and its mechanism

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Traditional Medicine Research 2025年第1期10卷 27-43页

作者： Shi-Bo feng Hai-Hui Jiang Hui-Li Kang yi Jiang Hua-Wei Zhang xiao-Mei Song Yu-Ze Li Wen-Li Huang Dong-Dong Zhang Chong Deng School of Pharmacy Shaanxi University of Chinese MedicineXianyang 712046China School of Pharmacy and Shaanxi Qinling Application Development and Engineering Center of Chinese Herbal Medicine Shaanxi University of Chinese MedicineXianyang 712046China Key Laboratory for Research and Development of“Qin Medicine”of Shaanxi Administration of Traditional Chinese Medicine Xianyang 712046China Shaanxi Key Laboratory of Research and Application of“Taibai Qi Yao” Xianyang 712046China

Background:The type 2 diabetes mellitus(T2DM)pharmacodynamic study of various parts of Schisandra sphenanthera was conducted in the previous stage,and it was found that dichloromethane extracted part(SDP)had a significant hypoglycemic ***,the components of SDP were analyzed,and the specific mechanism of its anti-T2DM was ***:We used a high-fat,high-sugar diet in combination with streptozotocin to induce a T2DM rat model,and the model rats were divided into two groups according to body weight and blood ***,oral glucose tolerance test,fasting blood glucose,low density lipoprotein cholesterol,superoxide dismutase,insulin,glycated hemoglobin,total cholesterol,nonesterified free fatty acids,alanine aminotransferase,high-density lipoprotein cholesterol,aspartate aminotransferase,malondialdehyde,and glutathione peroxidase were measured,organ indices were calculated,and pathological sections of pancreas and liver were *** 16S rRNA V3–V4 region of intestinal flora was sequenced to explore the effect of SDP on biochemical indicators and intestinal *** on the above indicators,the anti-T2DM mechanism of SDP in Schisandra sphenanthera was ***:After six weeks of administration,the biochemical indices of diabetic rats were diminished compared to the control *** SDP could significantly increase the gut microbialα-diversity index,resulting in significant changes in the flora of T2DM rats,with increased richness and diversity,reduced harmful flora,and significantly back-regulated the levels of acetic acid,propionic acid,and butyric ***:SDP can improve the symptoms associated with elevated blood glucose,dyslipidemia,elevated fasting insulin levels,and damaged glucose tolerance in *** against T2DM may be through the control of intestinal flora to normalize and exert anti-diabetic effect;its main active components may be lignans and terpenoids.

关键词： Schisandra sphenanthera T2DM intestinal flora HPLC

Effects of Substrate Crystallographic Orientations on Microstructure in Laser Surface-Melted Single-Crystal Superalloy:Theoretical Analysis

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Acta Metallurgica Sinica(English Letters) 2016年第8期29卷 763-773页

作者： Guo-Wei wang Jing-Jing Liang yi-Zhou Zhou tao Jin xiao-feng Sun Zhuang-Qi Hu Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

A geometric analysis technique for crystal growth and microstructure development in single-crystal welds had been previously *** the effect of welding conditions on the tendency of stray grains formation during solidification was *** the present work,these analytical methods were further *** with an original vectorization method,a 3D Rosenthal solution was used to determine thermal conditions of the ***,the dendrite growth orientation,the dendrite growth velocity and the thermal gradient along dendrite direction were calculated and lively ***,the tendency of stray grains formation in the solidification front was forecasted and its distribution was presented with a 3D *** results indicate that substrate orientation has some impacts on the crystal growth pattern,dendrite growth velocity,distribution of thermal gradient and stray *** on the research methods proposed in this work,any substrate crystallographic orientation can be studied,and predicted stray grains distribution can be visualized.

关键词： Single crystal Laser surface remelting Weld repair Modeling Stray grains distribution

Novel scheme for interference avoidance in cognitive radio based cellular networks

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The Journal of China Universities of Posts and Telecommunications 2012年第1期19卷 69-76页

作者： wang Sai XU xiao-dong CHEN Xin tao xiao-feng wang Qiang Wireless Technology Innovation Institute Key Laboratory of Universal Wireless CommunicationMinistry of Education Beijing University of Posts and TelecommunicationsBeijing 100876China.

The cognitive radio （CR） technology is believed to improve the spectrum efficiency. However, the interference problem has become a critical issue due to the coexistence of primary systems and CR systems. In this paper, the interferences in CR based cellular networks are discussed. Interference scenarios are analyzed, considering different interference sources. Meanwhile, an improved model named ＇Cognitive Interference Ring＇ is introduced to describe the interference range of each secondary user （SU）. Depending on the above analysis, graph coloring based dynamic power allocation （GCDPA） scheme is proposed for interference avoidance. Simulation results demonstrate that in CR based cellular networks, the interferences to primary users （PUs） can be effectively mitigated with the proposed GCDPA scheme, and the system throughput and power efficiency are both improved.

关键词： CR interference analysis interference avoidance graph coloring power allocation cellular networks