检索结果-南通市图书馆

NOX -Catalyzed Gas-Phase Activation of Methane: the Formation of Hydrogen

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2003年第2期12卷 90-92页

作者： Chaoxian Xiao, Zhen Yan, Yuan Koucollege of Chemistry and molecular Engineering, peking university, Beijing {3., china college of Chemistry and molecular Engineering Peking University

NO_x-catalyzed oxidation of methane without a solid catalyst wasinvestigated, and a hydrogen selectivity of 27% was obtained with an overall methane conversion of3.% and a free O_2 concentration of 1.7% at 700℃.

关键词： gas-phase oxidation methane activation methane nitrogen oxide hydrogen

The (⊿+2,2)-incidence coloring of outerplanar graphs

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2008年第5期18卷 575-578页

作者： Shudong Wanga,b,c, Jin Xu a,b, Fangfang Mac, Chunxiang Xua,b a institute of Software, School of Electronic Engineering and Computer science, peking university, Beijing {3., china b Key Laboratory of High Con dence Software Technologies, Ministry of Education, Beijing {3., china c college of Information science and Engineering, Shandong university of science and Technology, Qingdao 266510, china institute of Software School of Electronic Engineering and Computer Science Peking University Beijing 100871 China Key Laboratory of High Confidence Software Technologies Ministry of Education Beijing 100871 China college of Information science and Engineering Shandong University of Science and Technology Qingdao 266510 China

An incidence coloring of graph G is a coloring of its incidences in which neighborly incidences are assigned di erent colors. In this paper, the incidence coloring of outerplanar graphs is discussed using the techniques of exchanging colors and the double inductions from the aspect of con guration property. Results show that there exists a (D + 2,2)-incidence coloring in every outerplanar graph, where D is the maximum degree of outerplanar graph.

关键词： Incidence coloring Incidence chromatic number Outerplanar graph

Deposition features of Ni on self-assembled microtubule template from biolipid by electroless method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Chemistry 2004年第3期47卷 228-234页

作者： FU Yubin1,2, ZHANG Lide1, ZHENG Jiyong2, FU Shangang3.& ZHU Mingwei3.1. institute of Solid State Physics, Chinese Academy of sciences, Hefei 23.03., china 2. Luoyang Ship Material Research institute, Luoyang 47103., china 3. college of life science, Henan Normal university, Xinxiang 453.02, china 1. institute of Solid State Physics Chinese Academy of Sciences 230031 Hefei China 2. Luoyang Ship Material Research institute 471039 Luoyang China 3. college of life science Henan Normal University 453002 Xinxiang China

Diacetylenic glycero-phosphatidylcholine is a chiral molecule with amphiphilic property, and it can self-assembly into a lipid microtubular structure. The lipid microtubule is a stable structure formed by tightly wound helical ribbons, and the ribbon-wrapping patterns have a significant effect on their chemical deposition on the microtubules. The deposition of colloidal Pd catalyst occurs mainly on the helical edge of the wound helical ribbons to form helical deposition lines of colloidal Pd particles in the interior and exterior of the lipid microtubules, resulting in an uneven chemical deposition of Ni on the microtubules. Catalyzed by as-deposited colloidal Pd, metallized Ni microtubules are characterized by a helical form, which may be in relation to inner stress due to the thickness difference or the different deposition processes. The observation of microtom shows that metallized tubules have a hollow structure. Some metallized tubules have a kind of coaxial double layer structure observed in the direct experiment evidence, indicating that metallization can occur in the inner and outer surface of the lipid tubules. Both lipid microtubules and metallized microtubules can be used as vehicles for encapsulating biological active molecules to control their release and to develop micro-components in biological and mechanical systems. Keywords molecular self-assembly - lipid microtubules - helical pattern - site-specific deposition - electroless metallization

关键词： molecular self-assembly, lipid microtubules, helical pattern, site-specific deposition, electroless metallization.

Preparation and microstructure of CuO-CoO-MnO/SiO2 nanocomposite aerogels and xerogels as catalyst carriers

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2011年第4期21卷 330-335页

作者： Yue-qing ZHAO~1,Ying-hua LIANG~2,Xi-zhe ZHAO~3.Qian-yi JIA~4,Hong-sheng LI~4 1.college of Light Industry,Hebei United university,Tangshan 063.00,china 2.college of Chemical Engineering,Hebei United university,Tangshan 063.09,china 3.college of Printing and Packaging Engineering,Beijing institute of Graphic Communication,Beijing 102600,china 4.college of Materials science and Engineering,Hebei United university,Tangshan 063.09,china [a] college of Light Industry Hebei United University Tangshan 063000 China [b] college of Chemical Engineering Hebei United University Tangshan 063009 China [c] college of Printing and Packaging Engineering Beijing Institute of Graphic Communication Beijing 102600 China [d] college of Materials science and Engineering Hebei United University Tangshan 063009 China

CuO-CoO-MnO/SiO2nanocomposite aerogels and xerogels were prepared using tetraethyl orthosilicate（TEOS） as Si source,and aqueous solution of Cu,Co and Mn acetates as the precursor via sol-gel process,CO2supercritical drying（SCD） technique or ambient pressure drying *** microstructure of the CuO-CoO-MnO/SiO2nanocomposite aerogels and xerogels were characterized by field emission scanning electron microscopy（FE-SEM）,transmission electron microscopy（TEM） and X-ray diffraction（XRD）.The specific surface area,pore size and pore size distribution of the nanocomposite aerogels and xerogels were determined by the Brunauer-Emmett-Teller（BET） *** results showed that CuO-CoO-MnO/SiO2nanocomposite aerogels are porous,with a pore size distribution of 2-50 nm,an average pore size of 19.4 nm,a specific surface area of 3.4.9 m2/g and a particle size distribution of 10-150 nm,whereas the pore size distribution of CuO-CoO-MnO/SiO2composite xerogels is 1.7-128.6 nm,the average pore size is only 9.9 nm,the specific surface area is only 99.1 m2/g,and the particle size distribution is 100-500 *** structure of CuO-CoO-MnO/SiO2nanocomposite aerogels is favorable to increase the loading of catalysts.

关键词： composite aerogel composite xerogel catalyst carrier preparation microstructure

A taxonomic re-assessment in the Chinese Bupleurum(Apiaceae):Insights from morphology,nuclear ribosomal internal transcribed spacer,and chloroplast(trnH-psbA,matK) sequences

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systematics and Evolution 2011年第6期49卷 558-589页

作者： Chang-Bao WANG Xiang-Guang MA Xing-Jin HE(college of life science,Sichuan {3.,Chengdu 610064,china) (college of life science Sichuan University Chengdu 610064 China) *Correspondence: Xing-Jin HE *Correspondence: E-mail: xjhe@*** Tel.: 86-28-85415006 Fax: 86-28-85415006.

As one of the big genera in Apiaceae,Bupleurum *** received considerable attention from plant ***,there are still many gaps in our knowledge of this genus,especially of those species endemic to china that have often been excluded from previous *** spite of a few recent studies on the phylogeny and classification of the Chinese Bupleurum,the most essential problem of species delimitation still remains *** re-evaluate the taxonomy of the Chinese Bupleurum using morphological and molecular *** observations of living plants growing the field and herbarium specimens were made to understand the morphological variation and to ensure species identification for the molecular *** analyses were carried out on sequence data of nuclear ribosomal internal transcribed spacer(nrITS),trnH-psbA,and matK,using parsimony and Bayesian approaches to evaluate species *** of both nrITS and combined datasets of the three regions revealed the following results:(i)the Chinese Bupleurum species were divided into two major lineages;and(ii)most species were well defined,but some traditional inter-and infraspecific relationships were not *** results,along with the results of previous works support that the Chinese Bupleurum species were derived from two different lineages and should be placed in Neves and Watson’s subgenus *** detailed taxonomic re-assessment of several Chinese species resulted in new taxonomic recombinations with rank changes for three species:Bupleurum tenerum,***,and ***;new combination for one variety,*** ***;and the description of one variety and one species,*** *** and ***.

关键词： Chinese Bupleurum chloroplast sequences(trnH-psbA matK) morphology nrITS phylogenetic analyses taxonomy and new species.

A novel model-free approach for reconstruction of time-delayed gene regulatory networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

中国科学：生命科学英文版 2006年第2期49卷 190-200页

作者： JIANG Wei1,2, LI Xia1,2,3.4, GUO Zheng1,2,3. LI Chuanxing1, WANG Lihong1 & RAO Shaoqi1,5 1. Department of Bioinformatics, Harbin Medical university, Harbin 150086, china 2. Department of Computer science, Harbin {3. of Technology, Harbin 150080, china 3. School of life science and Technology, Tongji university, Shanghai 200092, china 4. Biomedical Engineering {3., Capital university of Medical sciences, Beijing 100054, china 5. Departments of Cardiovascular {13. and molecular Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA Department of Bioinformatics Harbin Medical University Harbin 150086 China Department of Computer science Harbin Institute of Technology Harbin 150080 China School of life science Technology Tongji University Shanghai 200092 China Biomedical Engineering institute Capital University of Medical Sciences Beijing 100054 China Departments of Cardiovascular medicine molecular Cardiology Cleveland Clinic Foundation Cleveland Ohio 44195 USA

Reconstruction of genetic networks is one of the key scientific challenges in functional genomics. This paper describes a novel approach for addressing the regulatory dependencies be-tween genes whose activities can be delayed by multiple units of time. The aim of the proposed ap-proach termed TdGRN (time-delayed gene regulatory networking) is to reversely engineer the dy-namic mechanisms of gene regulations, which is realized by identifying the time-delayed gene regu-lations through supervised decision-tree analysis of the newly designed time-delayed gene expres-sion matrix, derived from the original time-series microarray data. A permutation technique is used to determine the statistical classification threshold of a tree, from which a gene regulatory rule(s) is ex-tracted. The proposed TdGRN is a model-free approach that attempts to learn the underlying regula-tory rules without relying on any model assumptions. Compared with model-based approaches, it has several significant advantages: it requires neither any arbitrary threshold for discretization of gene transcriptional values nor the definition of the number of regulators (k). We have applied this novel method to the publicly available data for budding yeast cell cycling. The numerical results demonstrate that most of the identified time-delayed gene regulations have current biological knowledge supports.

关键词： gene regulatory networks, time delayed, decision tree.

Carbon isotope ratios of C_(4) plants in loess areas of North china

在线全文

学校读者我要写书评

暂无评论

science china Earth sciences 2006年第1期49卷 97-102页

作者： WANG Guoan1,2,3. HAN Jiamao 2, ZHOU Liping3. XIONG Xiaogang4, TAN Ming2, WU Zhenhai5 & PENG Jun6 1. Department of Plant Nutrition, china Agricultural university, Beijing 100094, china 2. {3. of Geology and Geophysics, Chinese Academy of sciences, Beijing 100029, china 3. college of Environmental sciences, MOE Laboratory for Earth Surface Processes, peking university, Beijing 100871, china 4. {3. of Botany, Chinese Academy of sciences, Beijing 100093. china 5. Northwest Sci-Tech university of Agriculture and Forestry, Yangling 712100, china 6. Network Center, china Agricultural university, Beijing 100094, china 1. Department of Plant Nutrition China Agricultural University Beijing 100094 China 2. institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 3. college of Environmental sciences MOE Laboratory for Earth Surface Processes Peking University Beijing 100871 China 4. institute of Botany Chinese Academy of Sciences Beijing 100093 China 5. Northwest Sci-Tech university of Agriculture and Forestry Yangling 712100 China 6. Network Center China Agricultural University Beijing 100094 China

Carbon isotope ratios (δ^(13.C) of 89 C_4 plant samples were determined fromthe loess area in North china. δ^(13.C values vary between -10.5per thousand and -14.6per thousandwith a mean of -12.6per thousand. Along a precipitation gradient from the semi-moist area to thesemiarid area, then to the arid area, the δ^(13.C values of C_4 plants show a slight decreasingtrend. The δ^(13.C values of C_4 plants in the dry season are found lower than those in the wetseason. These trends are opposite to those observed for C_3.species.

关键词： C4 plants, carbon isotope ratios, loess area.

Further study of sources of the imported cobalt-blue pigment used on Jingdezhen porcelain from late 13.to early 15 centuries

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2008年第3期51卷 249-259页

作者： DU Feng1 & SU BaoRu2 1 institute of Chemistry & molecular Engineering, Qingdao university of {3. & Technology, Qingdao 266000, china 2 college of Information {3. Technology, Qingdao university of {3. & Technology, Qingdao 266000, china institute of Chemistry & molecular Engineering Qingdao University of Science & Technology Qingdao 266000 China college of Information science Technology Qingdao University of Science & Technology Qingdao 266000 China

Based on the conclusion of modern scientific analysis: the cobalt-blue pigment applied on Jingdezhen official porcelain during Yuan Dynasty and prior to Xuande reign of Ming Dynasty (1271―1425) contains high iron and low manganese con- tents, and the cobalt during Xuande and after Xuande periods (after 1426) of Ming Dynasty contains high manganese and low iron contents, in combination with the traditional archaeological method, the related historical textual records were in- vestigated and analyzed, the imported cobalt employed on Jingdezhen official porcelain was studied comprehensively, systematically and logically. In fact, 'Su Ma Li Qing' (Samarra-blue) and 'Su Bo Ni Qing' (Sumatra-blue) are definitely different cobalt ores originated in different places, because of their very similar translitera- tions in Chinese, the confusion has appeared in ancient books for more than 400 years, which considered 'Su Ma Li Qing' and 'Su Bo Ni Qing' as the same co- balt-blue pigment. In this article the mistake was corrected, the possible producing places and the approximate eras of the two pigments imported to china and used at Jingdezhen were also suggested.

关键词： imported cobalt-blue pigments employed on official blue-and-white porcelain Yuan Dynasty early Ming Dy- nasty Mn/Fe content ratio Su Ma Li Qing (Samarra-blue) Su Bo Ni Qing (Sumatra-blue) scientific archae- ological research transliteration

LOD score exclusion analyses for candidate disease susceptibility genes using case-parents design

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2006年第1期16卷 30-38页

作者： DENG Hongwen1,2,3.and GAO Guimin2,4 (1.Laboratory of molecular and Statistical Genetics, college of life {3.s, Hunan Normal university, Changsha 410081, china 2.Osteoporosis Research Center, Creighton university Medical Center, Omaha NE 6813., USA 3. Department of Biomedical {3.s, Creighton university, Omaha NE 6813., USA 4. Virginia Bioin format ics institute and Department of Statistics, Virginia Polytechnic institute and State university, Blacksburg VA 24061-03.5, USA) [a]Laboratory of molecular and Statistical Genetics College of Life Sciences Human National University Changsha China [b]Osteoporosis Research Center Creighton University Medical Center Omaha NE USA [c]Department of Biomedical sciences Creighton University Omaha NE USA [d]Virginia Bioinformatics institute and Department of Statistics Virginia Polytechnic Institute and State University Blacksburg VA USA

The focus of almost all the association studies of candidate genes is to test for their importance. We recently developed a LOD score approach that can be used to test against the importance of candidate genes for complex diseases and quantitative traits in random samples. As a complementary method to regular association analyses, our LOD score approach is powerful but still affected by the population admixture, though it is more conservative. To control the confounding effect of population heterogeneity, we develop here a LOD score exclusion analysis using case-parents design, the basic design of the transmission disequilibrium test (TDT) approach that is immune to population admixture. In the analysis, specific genetic effects and inheritance models at candidate genes can be analyzed and if a LOD score is ≤ - 2. 0, the locus can be excluded from having an effect larger than that specified. Simulations show that this approach has reasonable power to exclude a candidate gene having small genetic effects if it is not a disease susceptibility locus (DSL) with sample size often employed in TDT studies. Similar to association analyses with the TDT in nuclear families, our exclusion analyses are generally not affected by population admixture. The exclusion analyses may be implemented to rule out candidate genes with no or minor genetic effects as supplemental analyses for the TDT. The utility of the approach is illustrated with an application to test the importance of vitamin D receptor (VDR) gene underlying the differential risk to osteoporosis.

关键词： association studies candidate genes case-parents design disease susceptibility locus exclusion mapping LOD score.