检索结果-南通市图书馆

维普期刊数据库博看期刊

Tensile ratcheting behaviors of bronze powder filled polytetrafluoroethylene

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2013年第1期7卷 103-109页

作者： Wenjuan xu hong gao LiLan gao xu CHEN Yong WANG School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

A series of tensile and ratcheting experiments for compacted polytetrafluoroethylene （PTFE） and bronze filled PTFE （PTFE/bronze） were conducted on dynamic mechanical analyzer （DMA-Q800）. The effects of mean stress, stress amplitude and temperature on the ratcheting behaviors of PTFE and PTFE/bronze were investigated. It is found that the stress-strain response of PTFE/bronze is nonlinear and its elastic modulus is higher than that of pure PTFE. For uniaxial ratcheting test, the dissipation strain energy density （DSED） decreases rapidly in the first l0 cycles and approaches a constant after 20 cycles. The ratcheting strain and the DSED corresponding to 100 cycles increase with increasing mean stress, stress amplitude and temperature. Additionally, the DSED and ratcheting strain of PTFE/bronze are much lower than those of pure PTFE under the same experimental conditions. It is also found that both pure PTFE and PTFE/bronze present cyclic hardening characteristics. Above all, the addition of bronze can improve both the uniaxial tensile property and the cyclic property of PTFE.

关键词： bronze filled polytetrafluoroethylene (PTFE/ bronze) uniaxial tensile behavior ratcheting behavior dissipation strain energy density (DSED)

2-D NUMERICAL SIMULATION OF RADIONUCLIDE TRANSPORT IN THE LOWER YANGTZE RIVER

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第5期24卷 702-710页

作者： ZHANG Wan-shun ZHAO Yan-xin xu Yan-hong WANG Yong-gui xu gao-hong School of Resource and Environmental Science Wuhan University Wuhan 430079 China Bureau of Hydrology of Changjiang Water Resources Commission Wuhan 430010 China

The assessment of the radiological impact of the liquid discharges from nuclear power plants is a major issue for the envi- ronmental protection. In this study, a numerical model for the radionuclide transport in the aquatic environment is built, based on the hydrodynamic equations, including the complete set of Saint-Venant equations, the sediment transport equations, with consideration of several different particle sizes and the deposition and erosion of the suspended sediments, and the radionuclide transport equations The exchanges of radionuclides between water, suspended matter and bed sediments are described in terms of kinetic transfer coe- fficients. The model is used to simulate the transport of the radionuclides discharged from a planned nuclear power plant project to be sited along the lower Yangtze River. From the model results, one may see the detailed temporal-spatial evolution of the radio- nuclide contamination in the solution, in the suspended matter and in the bed sediments. The model can be used as a basic tool for studying the environmental impacts of the liquid discharges from nuclear facilities on a river system.

关键词： 2-D numerical model radionuclide Yangtze River sediment

Thermal Behavior,Nonisothermal Decomposition Reaction Kinetics of Mixed Ester Double-base Gun Propellants

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2008年第5期24卷 608-614页

作者： YI Jian-hua ZHAO Feng-qi xu Si-yu gao hong-xu HU Rong-zu Xi＇an Modern Chemistry Research Institute Xi＇an 710065 P. R. China

The thermal decomposition behavior and nonisothermal reaction kinetics of the double-base gun propellants containing the mixed ester of triethyleneglycol dinitrate（TEGDN） and nitroglycerin（NG） were investigated by thermogravimetry（TG） and differential thermogravimetry（DTG）, and differential scanning calorimetry（DSC） under the high-pressure dynamic ambience. The results show that the thermal decomposition processes of the mixed nitric ester gun propellants have two mass-loss stages. Nitric ester evaporates and decomposes in the first stage, and nitrocellulose and centralite II（C2） decompose in the second stage. The mass loss, the DTG peak points, and the terminated temperatures of the two stages are changeable with the difference of the mass ratio of TEGDN to NG. There is only one obvious exothermic peak in the DSC curves under the different pressures. With the increase in the furnace pressure, the peak temperature decreases, and the decomposition heat increases. With the increase in the content of TEGDN, the decomposition heat decreases at 0.1 MPa and rises at high pressure. The variety of mass ratio of TEGDN to NG makes few effect on the exothermic peak temperatures in the DSC curves at different pressures. The kinetic equation of the main exothermal decomposition reaction of the gun propellant TG0601 was determined as： dα/dt=1021.59（1-α）3e-2.60×104/T. The reaction mechanism of the process can be classified as chemical reaction. The critical temperatures of the thermal explosion（Tbe and Tbp） obtained from the onset temperature（Te） and the peak temperature（Tp） are 456.46 and 473.40 K, respectively. ΔS≠, ΔH≠, and ΔG≠ of the decomposition reaction are 163.57 J·mol^-1·K^-1, 209.54 kJ·mol^-1, and 133.55 kJ·mol^-1, respectively.

关键词： Mixed nitric ester gun propellant Triethyleneglycol dinitrate Thermal behaviors Nonisothermal decomposition reaction kinetics

High variability of the gvpA-gvpC region in Microcystis

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第11期17卷 1290-1295页

作者： xu Min, xu xudong, gao hong and Kong Renqiu(The State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China) State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Acad. of Sci. Wuhan 430072 China

Gas vesicles provide buoyancy to Microcystis and other common cyanobacterial bloom-forming species. gvpA and gvpC are structural genes encoding gas vesicle proteins. Phylogenetic analyses of 10 Microcystis strains/uncultured samples showed that gvpC and each intergenic segment of the gvpA-gvpC region can be divided into two types. The combination of different types of gvpC and intergenic segments is an important factor that diversifies this genomic region. Some Microcystis strains isolated in China possess a 172 to 176 bp sequence tag in the intergenic segment between gvpA and gvpC. The gvpA-gvpC region in Microcystis can be divided into at least 4 classes and more numbers of subclasses. Compared to rbcLX and other regions, the high variability of the gvpA-gvpC region should be more useful in identifying geographical isolates or ecotypes of Microcystis.

关键词： Microcystis gvpA-gvpC diversity

Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第3期8卷 497-513页

作者： JiaRui Wei Xiao Liu JiYao xu QinZeng Li hong gao State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Institute of Electromagnetic Wave School of PhysicsHenan Normal UniversityXinxiang Henan 453000China

We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)*** to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan *** land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper *** 40°N/S,the peaks were mainly above the topographic regions during the *** 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain *** the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from *** results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic *** found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S.

关键词： topography fine structures stratospheric gravity waves Constellation Observing System for Meteorology Ionosphere and Climate-2(COSMIC-2) dissipation layers

青稞酒糟中β-葡聚糖提取工艺优化及理化特性分析

在线全文

学校读者我要写书评

暂无评论

食品安全质量检测学报 2024年第5期15卷 180-188页

作者：李晶曹颖张彧格许洪高纪凤娣石莹鲁绯北京市营养源研究所有限公司北京100069 北京城市学院生物医药学部北京100094 河北省菊苣膳食纤维技术创新中心承德130826

目的探究青稞酒糟中β-葡聚糖提取工艺及其理化特性。方法通过单因素和响应面实验优化确定β-葡聚糖提取工艺。利用傅里叶红外光谱(Fourier transform infrared spectroscopy, FT-IR)和高效排阻色谱-示差折光检测器-多角度激光光散射... 详细信息

目的探究青稞酒糟中β-葡聚糖提取工艺及其理化特性。方法通过单因素和响应面实验优化确定β-葡聚糖提取工艺。利用傅里叶红外光谱(Fourier transform infrared spectroscopy, FT-IR)和高效排阻色谱-示差折光检测器-多角度激光光散射仪(high performance size exclusion chromatography-differential refraction detector-multi-angle laser light scatter, HPSEC-RID-MALLS)联用测定提取物中β-葡聚糖的结构和分子量,并对其加工特性及流变特性进行分析。结果青稞酒糟中β-葡聚糖最优提取条件为:料液比为1:11 (m:V)、pH 8.5、提取温度80℃、搅拌速度600 r/min、提取时间3.0 h,此条件下提取率为16.29%。FT-IR检测结果表明,提取样品中具有β-葡聚糖特征吸收峰。多糖重均分子量为7.84×10^(4)Da,在100~140℃高温条件和中性偏碱性条件下稳定,在碱性条件及低盐离子浓度条件下促进溶解。流变特性结果表明, β-葡聚糖水溶液表现出非牛顿流体的剪切稀化特性,其表观黏度存在浓度依赖性,具有固体弹性特性。结论从青稞酒糟中提取的β-葡聚糖具有较好的加工特性及流变性,为青稞酒糟的综合加工及增值化利用提供思路。

关键词：青稞酒糟 β-葡聚糖提取工艺分子量理化特性流变特性

Alloy/layer double hydroxide interphasic synergy via nano-heterointerfacing for highly reversible CO_(2)redox reaction in Li-CO_(2)batteries

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 5206-5215页

作者： Tianzhen Jian Wenqing Ma Jiagang Hou Jianping Ma Xianhong Li Haiyang gao Caixia xu hong Liu Institute for Advanced Interdisciplinary Research(iAIR) Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of ShandongSchool of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China Kyiv College at Qilu University of Technology Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China Shandong Sacred Sun Power Sources Co. Ltd.Qufu 273100China

Li-CO_(2)batteries are among the most intriguing techniques for balancing the carbon cycle,but are challenged by the annoyed thermodynamic barrier of the Li_(2)CO_(3)decomposition ***,we demonstrate the electrocatalytic performances of two-dimensional(2D)CoAl-layer double hydroxide(LDH)nanosheets can be significantly improved by trans-dimensional crosslinking with three-dimensional(3D)multilevel nanoporous(MP)-RuCoAl alloy(MP-RuCoAl alloy⊥CoAl-LDH).The MP-RuCoAl alloy⊥CoAl-LDH with multiscale pore channels and abundant nano-heterointerface is directly prepared by controllable etching Al from a Ru-Co-Al master alloy along with simultaneous partial oxidization of Al and Co *** MP-RuCoAl is composed of various intermetallic compounds and Ru with abundant grain boundaries,and forms numerous heterointerface with 2D CoAl-LDH *** multiscale porous metallic network benefits mass and electron transportation as well as discharge product storage and enables a rich multiphase reaction *** situ differential electrochemical mass spectrometry shows that the mass-to-charge ratio in the charging process is~0.733 which is consistent with the theoretical value of 3/4,stating that the reversible co-decomposition of Li_(2)CO_(3)and C can be achieved with the MP-RuCoAl alloy⊥*** Ketjen black(KB)/MP-RuCoAl⊥CoAl-LDH battery demonstrates a high cyclability for over 2270 h(227 cycles)with a lower voltage gap stabilized at~1.3 V at 200 mA·g^(−1).Our findings here provide useful guidelines for developing high efficiency transition metal based electrocatalysts by coupling with conductive porous substrate for impelling the development of practical Li-CO_(2)battery systems.

关键词： heterojunction interface nanoporous Li-CO_(2)battery dealloying

Nickel-catalyzed carbonylative four-component 1,4-dicarbofunctionalization of 1,3-enynes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第6期67卷 2029-2038页

作者： Yan Zhao Qi-Chao Shan hong Xin Pin gao xu Yang Xin-Hua Duan Li-Na Guo Department of Chemistry School of ChemistryXi’an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy StorageMaterials and DevicesMinistry of EducationXi’an Jiaotong UniversityXi’an710049China School of Electrical Engineering Xi’an Jiaotong UniversityXi’an710049China

An efficient Ni-catalyzed four-component 1,4-carbocarbonylation of 1,3-enynes with activated alkyl halides and arylboronic acids under atmospheric pressure of CO is *** tuning the electronic and steric effects of alkyl radicals,both electronrich and electron-deficient 1,3-enynes were compatible with this *** protocol features mild conditions,broad substrate scope,excellent functional group compatibility and facile gram-scale synthesis,providing a practical approach to the quaternary carbon center-containing allenyl *** study revealed that the acyl-NiIIspecies plays an important role in both the coupling and the alkyl radical generation processes.

关键词： Ni catalysis four-component 1 4-carbocarbonylation 1 3-enynes

Prominent removal of trace lead(Ⅱ)ions from polluted water by terephthalic acid reformed Al/Zn metal organic nanoflakes

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第1期84卷 81-88页

作者： Junhua Li Lingshu gao Junmao hong Xiaofeng Shi Sifang Kong Jingyu Wang Hassan Algadi Benbin xu Zhanhu Guo School of Chemistry and Chemical Engineering North University of ChinaTaiyuan030051China School of Traffic&Environment Shenzhen Institute of Information TechnologyShenzhen518172China Department of Electrical Engineering Faculty of EngineeringNajran UniversityNajran11001Saudi Arabia Mechanical and Construction Engineering Faculty of Engineering and EnvironmentNorthumbria UniversityNewcastle Upon TyneNE18STUK

Terephthalic acid reformed Al/Zn metal organic nanoflake was prepared and functionalized with trie-thylamine(T-AlZn).Without adding terephthalic acid,there was no product of metal organic nanoflake.T-AlZn has a remarkable performance in removing trace lead(Ⅱ)ions(Pb^(2+)).The adsorption equipoise with the removal rate≥97%was reached within 35 *** removal rates of T-AlZn for Pb^(2+)declined by only 16.73%after four *** adsorption of T-AlZn for Pb^(2+)follows the Langmuir isotherms model and pseudo-second-order dynamics *** utmost adsorption competence was calculated as 215.27 mg g^(-1).The T-AlZn adsorbent exhibits a bright prospect in the adsorption for Pb^(2+)and is a considerable candidate in the disposal of industrial sewage.

关键词： Metal organic complex Nanoflake Trace level Pb^(2+) Adsorption