检索结果-南通市图书馆

Peptides and polyketides isolated from the marine sponge-derived fungus Aspergillus terreus SCSIO 41008

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2019年第2期17卷 149-154页

作者： LUO Xiao-Wei LIN Yun LU yong-Jun zhou Xue-feng LIU yong-Hong CAS Key Laboratory of Tropical Marine Bio-resources and Ecology Guangdong Key Laboratory of Marine Materia MedicaSouth China Sea Institute of Oceanology Chinese Academy of Sciences University of Chinese Academy of Sciences School of Life Sciences Sun Yat-Sen University Biomedical Center of Sun Yat-Sen University

Two new isomeric modified tripeptides,aspergillamides C and D(compounds 1 and 2),together with fifteen known compounds(compounds 3-17),were obtained from the marine sponge-derived fungus Aspergillus terreus SCSIO *** structures of the new compounds,including absolute configurations,were determined by extensive analyses of spectroscopic data(NMR,MS,UV,and IR)and comparisons between the calculated and experimental electronic circular dichroism(ECD)*** I(compound 11)exhibited strong inhibitory effects against Mycobacterium tuberculosis protein tyrosine phosphatase B(MptpB)with the IC_(50) being 5.11±0.53μmol·L^(–1),and acted as a noncompetitive inhibitor based on kinetic analysis.

关键词： Aspergillus terreus Aspergillamides Polyketides MptpB inhibitor

Comprehensive Evaluation of Tobacco Ecological Suitability of Henan Province Based on GIS

在线全文

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2010年第4期9卷 583-592页

作者： CHEN Hai-sheng LIU Guo-shun YANG yong-feng YE Xie-feng SHI zhou National Tobacco Cultivation and Physiological and Biochemical Center Henan Agricultural University Zhengzhou 450002 P.R. China Zhejiang Tongji Science and Technology Vocational College Hangzhou 311231 P.R.China Institute of Agricultural Remote Sensing and Information Technology College of Environment and Resource Science Zhejiang University Hangzhou 310029 P.R.China

The growth of tobacco is sensitive to environment conditions. The tobacco production is strictly restricted by regional cultivated land. Based on the principal of hiberarchy analysis and fuzzy mathematics and the technique of geographic information system （GIS）, the comprehensive evaluation of tobacco ecology suitability were studied according to the actual circumstances of the whole Henan tobacco planting regions, China. The evaluation index system of tobacco ecology suitability of Henan tobacco planting regions was established by choosing 17 evaluation indexes from 3 respects of climate, soil and landform with Delphi method. Furthermore, the membership function was set up according to the effects of each ecology factors on the growth and quality of tobacco suitability. And the analytical hierarchy process （AHP） was used to determine the weight of indexes by using quantitative analysis. Then the tobacco ecology suitability map of Henan tobacco plantation was drawn with GIS software mapGIS. It is found that the most areas of the western and southern parts of Henan Province, China, are the highly suitable regions, accounting for 22.52% of Henan tobacco planting areas. It is because that there are medium air temperature, sunshine and rainfall, medium soil pH value, and high contents of soil organic matter in the regions. Moreover, the topography is hill and massif, and the height above sea level is between 150-800 m there. Some areas of the southern and middle parts of Henan Province are the suitable ones, accounting for 34.99% of Henan tobacco planting areas. It is because that there are enough rainfall, medium air temperature, high contents of available N and available K in the soil in these regions. There are less suitable regions in the northern and eastern parts of the investigated regions because of drought, too high pH value and CI in the soil and irrigation water, accounting for 35.54% of the whole areas. It can be conducted rapidly and correctly by combining

关键词： GIS flue-cured tobacco evaluation factors AHP ecology suitability

Design,Synthesis and Characterization of Coordination Polymer from[Cu(DMF)_(4)(SCN)_(2)]as a Precursor

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2014年第12期32卷 1287-1293页

作者： Xiaotong Liu feng zhou Qiuxuan zhou Lihua Wang yong Zhang Qingfeng Xu Jianmei Lu Key Laboratory of Key Laboratory of the National Petroleum and Chemical Industry for Organic Waste Water Disposal by Absorption Technology Soochow UniversitySuzhouJiangsu 215123China Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsu 215123China

This paper is focused on investigation of coordination polymers constructed by Cu(II)and rigid pyridyl ligands,such as 4,4'-bipyridyl-1,2,4-triazole(Hpytz)and 1,10-phenanthroline(phen)from a mononuclear precursor[Cu(DMF)_(4)(NCS)_(2)](1).As expected,the complex was self-assembled with phen to form a 1D double-stranded chain of[Cu(phen)(μ-SCN)_(2)]∞(2),with Hpytz to form 1D zigzag chain of[Cu_(2)(μ-Hpytz)_(2)(NCS)_(2)(DMF)_(2)(μ-SCN)_(2)]∞(3)in which thiocyanate anion linked the Cu-μ-Hpytz-Cu chain into an infinite 2D network via weak Cu…S *** treat 3 with the bridged anion dca,a novel 3D framework[Cu(μ-Hpytz)(μ-dca)(μ-SCN)]∞(4)was obtained in which Cu-μ-Hpytz-Cu chain is preserved and both thiocyanate anion and dicyanamide(dca)act as bridging *** addition,complex 3 was applied as a metal catalyst in polymerization of MMA in aqueous solution at room temperature.

关键词： copper molecular design dipyridyl triazole ligand crystal structure

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

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

Acta Metallurgica Sinica(English Letters) 2019年第4期32卷 517-525页

作者： Peng Liu Zhao-Kuang Chu yong Yuan Dao-Hong Wang Chuan-yong Cui Gui-Chen Hou Yi-zhou zhou Xiao-feng Sun Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Xi'an Thermal Power Research Institute Co.Ltd. Jiangsu Feiyue Pump Group Co.Ltd.

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous *** with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.

关键词： Austenitic heat resistant steel Microstructure Mechanical property Fracture mode

Inhibitory effects of EGFR antisense oligodeoxynucleotide in human colorectal cancer cell line

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2000年第5期6卷 747-749页

作者： yong He Jun zhou Jin Sheng Wu Ke feng Dou Department of Hepatobiliary Surgery Xijing Hospitalthe Fourth Military Medical UniversityXi’an 710032China Department of Pathology Qindu Hospitalthe Fourth Military Medical UniversityXi’anChina Department of General Surgery Tangdu Hospitalthe Fourth Military Medical UniversityXi’an China

INTRODUCTIONEpidermal-growth-factor receptor(EGFR) is apolypeptide with 1186 amino acids,which binds toEGF family growth *** major naturalligands in the family interact with EGFR:one isEGF,the other is transforming growth factor-α(TGF-α).When EGF or TGF-α,binds to EGFR,tyrosine kinase activity is induced which in turntriggers a series of events regulating the *** importance of EGFR in growthregulating pathways was confirmed by the fact

关键词： colorectal neoplasms oligonucleotides antisense epidermal growth factor receptor gene therapy liposomes flow cytometry

Low-dimensional chaos and fractal properties of long-term sunspot activity

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

Research in Astronomy and Astrophysics 2014年第1期14卷 104-112页

作者： Shuang zhou yong feng Wen-Yuan Wu Yi Li Jiang Liu Chongqing Key Laboratory of Automated Reasoning and Cognition Chongqing Institute of Green and Intelligent TechnologyChinese Academy of Sciences University of Chinese Academy of Sciences

Two primary solar-activity indicators- sunspot numbers （SNs） and sunspot areas （SAs） in the time interval from November 1874 to December 2012 - are used to determine the chaotic and fractal properties of solar activity. The results show that （1） the long-term solar activity is governed by a low-dimensional chaotic strange attractor, and its fractal motion shows a long-term persistence on large scales; （2） both the fractal dimension and maximal Lyapunov exponent of SAs are larger than those of SNs, implying that the dynamical system of SAs is more chaotic and complex than SNs; （3） the predictions of solar activity should only be done for short- to mid-term behaviors due to its intrinsic complexity; moreover, the predictability time of SAs is obviously smaller than that of SNs and previous results.

关键词： methods: data analysis -- Sun: activity -- Sun: sunspots

Tsallis Entropy Based q-Gaussian Density Model and Its Application in Measurement Accuracy Improvement

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2017年第1期15卷 77-82页

作者： Xuan Xie Xi-feng Li Qi-Zhong zhou yong-Le Xie School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 610054China

The central limit theorem guarantees the distribution of the measurand is Gaussian when the number of repeated measurement is infinity, but in many practical cases, the number of measurement times is limited to a given number. To overcome this contradiction, this paper firstly carries out the maximum likelihood estimation for parameter q in qGaussian density model developed under the maximum Tsallis entropy principle. Then the q-Gaussian probability density function is used in the particle filter to estimate and measure the nonlinear system. The estimated parameter q is related to the ratio between the measurement variance and the given variance, which indicates that the measurement accuracy cannot be improved if we only increase the repeated measurement times. Via using the proposed q-Gaussian density model,the measurement error（the average mean square error）of the estimation results can be reduced to a considerable level where the number of repeated measurement is limited. The experimental example is given to verify the proposed model and the measurement results prove the correctness and effectiveness of it.

关键词： variance entropy overcome infinity likelihood guarantees sequentially verify carries contradiction

BLOCK ITERATIVE METHODS FOR LINEAR ALGEBRAIC EQUATION AND DOMAIN DECOMPOSITION METHOD FOR INCOMPRESSIBLE VISCOUS FLOW

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2002年第4期14卷 73-80页

作者： Ren, An-Lu Zou, Jian-feng zhou, yong-Xia Li, Guang-Wang Dept. of Mech. Zhejiang Univ. Hangzhou 310027 China

It was proved numerically that the Domain Decomposition Method CDDM) with one layer overlapping grids is identical to the block iterative method of linear algebra equations. The results obtained by using DDM could be in reasonable agreement with the results of full-domain simulation. With the three dimensional solver developed by the authors, the flow field in a pipe was simulated by using the full-domain DDM with one layer overlapping grids and with patched grids respectively. Both of the two cases led to the convergent solution. Further research shows the superiority of the DDM with one layer overlapping grids to the DDM with patched grids. A comparison between the numerical results obtained by the authors and the experimental results given by Enayet[3] shows that the numerical results are reasonable.

关键词： Computational fluid dynamics Computer simulation Iterative methods Linear equations Viscous flow

Experimental research on blast power of fiber reinforced anti-hard target warhead

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2017年第3期13卷 212-218页

作者： Bin Liang Jie-qun zhou Gao-peng feng yong-gang Lu Institute of Systems Engineering China Academy of Engineering Physics

Fiber reinforced anti-hard-target warhead is a new-type sample munition, which is only designed based on theoretical analysis and numerical simulation in laboratory. This warhead consists of carbon composite casings and high explosive, which can greatly reduce the damage to objects outside the damage range. In order to evaluate its blasting damage effect on concrete target, the three types of charges were researched by means of experiment, which are bare charge, charge with carbon composite material shell and charge with steel shell. Experimental results show that the peak overpressure of charge with carbon fiber composite shell is higher than that of charge with steel shell, but is lower than that of bare charge in the case of the same TNT equivalence. No fragments and fragment effect exist for distant target under the condition of charge with carbon fiber composite shell. However, the experimental result of the charge with steel shell is completely contrary. According to the blast effect in the concrete target, the charge with carbon composite material shell is optimal in matched impedance and detonation ***, the effective energy produced by the detonation of explosive with carbon composite material shell is the largest.

关键词：爆炸效应威力试验纤维增强战斗部碳纤维复合材料复合材料壳体爆破损伤混凝土靶