检索结果-南通市图书馆

new family of single-component ni catalysts for ethylene polymerization to high and ultrahigh molecular weight polyethylene

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 2020年第6期63卷 753-754页

作者： Artem A.Antonov Wen-Hua Sun konstantin P.Bryliakov Boreskov Institute of Catalysis Pr.Lavrentieva 5Novosibirsk 630090Russia novosibirsk State University Pirogova 1Novosibirsk 630090Russia Key Laboratory of Engineering Plastics and Beijing national Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of SciencesBeijing 100190China CAS Research/Education Center for Excellence in Molecular Sciences University of Chinese Academy of SciencesBeijing 100049China

Since the milestone discovery of ni(II)salicylaldiminate catalysts by Grubbs and co-workers[1],nickel(II)complexes with n,n-and n,O-donor ligands have strengthened their lead in the search for highly active platforms for olefins homo-and copolymerization with various co-monomers,including those with polar groups,to achieve polymers with precisely controlled microstructures[2,3].

关键词： discovery catalysts co-monomers

Taxonomic Composition and Spatial Distribution of Meiofauna Community from a Sandy Intertidal Zone in Sishili Bay, Yellow Sea Coast (northern China)

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2022年第5期21卷 1389-1401页

作者： PAVLYUK Olga n TREBUKHOVA Yulia A SHCHERBAKOV Ilya A TARASOVA Tatiana S LUTAEnKO konstantin A CHEn Linlin SOnG Bo LI Xiaojing LI Baoquan A.V.Zhirmunsky national Scientific Center of Marine Biology Far Eastern BranchRussian Academy of SciencesVladivostok 690041Russia Yantai Institute of Coastal Zone Research Chinese Academy of SciencesYantai 264003China

The meiofauna composition and trophic groups of the nematode communities have been studied at a sandy intertidal zone in Sishili Bay along the Yantai coast(Yellow Sea,China).nematoda was dominant among the 11 groups of *** meiofaunal densities were low,ranging between 111±47 and 542±131 ind./10 cm^(2).Results obtained from the correlation analysis made it possible to determine several factors that influence species composition and ***,sediment granulometry significantly affected the *** highest abundance was found in fine-grained sediments(318.77±126 ind./10 cm^(2))com-pared to coarse-grained sediments(175±82 ind./10 cm2).nematodes were predominant in all studied sites.A total of 70 species be-longing to 52 genera and 18 families were identified in the study *** was a significant difference in nematode abundance(AnOVA,F=2.38,Pn the three *** communities were characterized by a high level of species diversity in sediments composed mainly of very-fine sands(>63μm),with dominant species belonging to the genus Bathylaimus,Ptycho-laimellus,Spirinia,and *** trophic groups were dominated by non-selective deposit feeders(40.7%)and epistrate feed-ers(41.29%).In contrast,the species composition in medium grain sands was characterized by a low species diversity index and a high Simpson dominance *** communities showed similar dominant species compositions belonging to a single genus Bathylaimus,Enoplolaimus,and Oncholaimus,and in terms of trophic structure-representatives of deposit feeders(46.15%),preda-tors,and omnivores(64.71%)*** divergence of meiofaunal community structures can be explained by abiotic factors such as sediment grain size,salinity,and organic carbon ***,sediment particle size can explain the diversity of nematodes at the level of in abundance,diversity indices,and trophic *** highest nematode density and diversity coincided with

关键词： meiofauna nematodes sandy intertidal zone sediment grain size Yellow Sea

On the winter enhancement of adaptive humoral immunity: hypothesis testing in desert hamsters (Phodopus roborovskii: Cricetidae, Rodentia) kept under long-day and short-day photoperiod

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2020年第3期15卷 232-247页

作者： nina Yu.VASILIEVA Anastasiya M.KHRUSHCHOVA Alexander V.KUPTSOV Olga n.SHEKAROVA Olga V.SOKOLOVA Dehua WAnG konstantin A.ROGOVIn Severtsov Institute of Ecology and Evolution RAS MoscowRussia Institute of Zoology Chinese Academy of Science Chaoyang DistrictBeijingChina

We tested the winter immunity enhancement hypothesis(WIEH)on male desert hamsters(Phodopus roborovskii)kept under long-day(LD)and short-day(SD)*** assumed that under SD in a laboratory,the adaptive humoral immune responsiveness to the antigenic challenge would be enhanced due to the lack of winter physical stressors and food shortages and/or because of the action of an endogenous winter bolstering mechanism,while under LD the immune responsiveness would be suppressed by the activity of the reproductive *** results support the WIEH in *** did not find a difference in antibody production in response to sheep erythrocytes between SD and LD hamsters,but SD males had the lower number of granulocytes and the higher number of lymphocytes in white blood cell *** activity was lower in SD *** males demonstrated an increase in their mass-specific resting metabolic rate,their mass-specific maximal metabolic rate and their level of *** result of a generalized linear model analysis indicates the negative effect on secondary immunoresponsiveness to sheep erythrocytes of mid-ventral gland size,the organ characterizing individual reproductive quality,and designates a tradeoff between antibody production and reproductive *** mass-independent maximal metabolic rate also negatively affected antibody production,indicating a tradeoff between maximal aerobic performance and the adaptive immune *** higher stress in SD males seems to be the most likely reason for the lack of the effect of daylight duration on antibody production.

关键词： adaptive humoral immunity desert hamster photoperiodicity winter immunoenhancement

nucleation of dislocations and twins in fcc nanocrystals: Dynamics of structural transformations

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 Materials Science & Technology 2019年第1期35卷 201-206页

作者： Aleksandr V.Korchuganov Aleksandr n.Tyumentsev konstantin P.Zolnikov Igor Yu.Litovchenko Dmitrij S.Kryzhevich Elazar Gutmanas Shouxin Li Zhongguang Wang Sergey G.Psakhie Institute of Strength Physics and Materials Science of Siberian Branch of Russian Academy of Sciences national Research Tomsk State University Technion–Israel Institute of Technology Shenyang national Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

This paper reports on a molecular dynamics study of structural rearrangements in a copper nanocrystal during nucleation of plastic deformation under uniaxial tension. The study shows that the resulting nucleation of partial dislocations on the free surface and their glide occurs through local fcc→bcc→hcp transformations via consistent atomic displacements. We propose an atomic model for the generation of dislocations and twins based on local reversible fcc→bcc→fcc transformations, with the reverse one proceeding through an alternative system. The model gives an insight into possible causes and mechanisms of the generation of partial dislocations and mechanical twins in two and more adjacent planes of plastically deformed nanocrystals. The obtained data allow a better understanding of how plasticity is generated in nanostructured materials.

关键词： Lattice defects Dislocation nanotwin Atomic model Molecular dynamics simulations

Magnetic field hyperactivity during the early neoproterozoic: A paleomagnetic and cyclostratigraphic study of the Katav Formation, southern Urals, Russia

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2023年第4期14卷 42-56页

作者： Inessa V.Golovanova konstantin n.Danukalov Raushaniia Yu.Salmanova natalia M.Levashova nikita P.Parfiriev nina D.Sergeeva Joseph G.Meert Institute of Geology-Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences(IG UFRC RAS) Russia Geological Institute Russian Academy of SciencesMoscowRussia Department of Earth and Planetary Sciences Neil Opdyke Paleomagnetic LaboratoryUniversity of FloridaGainesvilleFL 32611United States

We present a detailed magnetostratigraphic and cyclostratigraphic profile through the Riphean(Tonian)Katav Formation in the southern *** study confirms the primary nature of the magnetization in these *** cyclostratigraphic study identified several orbital periods including the 405 ka long *** allows us to quantify the reversal frequency in the Katav and our estimates range of 7–12 reversals per million *** on our study,we identify an interval of magnetic field reversal hyperactivity in the neoproterozoic *** estimates for the Katav are contentious and range somewhere between 800 Ma and 900 Ma based on carbonate Pb-Pb ages and stable isotope *** paleomagnetic poles obtained in this study of the Katav(and overlying Inzer)Formation do not fit anywhere on the Baltica apparent polar wander path between 1100 Ma and 900 ***,they lie 90away from the 900 Ma segment of the *** tentatively estimate their age to be closer to 800 Ma and perhaps confirm a previously hypothesized pulse of rapid true polar wander between 825 Ma and 790 Ma.

关键词： Magnetostratigraphy Cyclostratigraphy Hyperactive reversal True polar wander Tonian

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

溶液中蛋白质的气液荷电萃取电离质谱研究

分析化学 2017年第12期45卷 1937-1943页

作者：寇伟张华 konstantin Chingin 陈焕文吉林大学无机合成与制备化学国家重点实验室东华理工大学江西省质谱科学与仪器重点实验室

利用自主研制的气液荷电萃取电离装置实现了溶液中蛋白组分的荷电萃取电离直接质谱分析。系统考察了所用气体种类、气泡路径长度、溶液电压、气压等条件对溶液中溶菌酶等蛋白荷电萃取电离的影响,以期得到最佳蛋白质信号。在以CO;为萃取... 详细信息

利用自主研制的气液荷电萃取电离装置实现了溶液中蛋白组分的荷电萃取电离直接质谱分析。系统考察了所用气体种类、气泡路径长度、溶液电压、气压等条件对溶液中溶菌酶等蛋白荷电萃取电离的影响,以期得到最佳蛋白质信号。在以CO;为萃取气体、气泡路径长度32 cm、溶液电压+2 k V、气压0.05 MPa条件下,溶菌酶在水、纯水稀释200倍尿液、未稀释尿液中的浓度分别为1×10;mol/L、1×10;mol/L、1×10;mol/L时获得谱图信噪比（S/n≥3）类似,信号强度不受样品管内径大小影响,所用尿液最小体积为6 m L,但对珍稀样品可进一步减少用量。与ESI-MS相比,本方法获得更多低价态蛋白质离子,对溶液中的小分子基体、无机盐具有更强的耐受性,且辣根过氧化物酶经气液苛电萃取电离能保留53.9%活度。本方法具有无需复杂样品预处理、无化学试剂污染的特点,有望为分析复杂基质中蛋白质提供一种新方法。

关键词：蛋白样品气泡荷电萃取电离质谱分析

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2020年第22期26卷 2931-2947页

作者： Tea L Laursen Thomas D Sandahl konstantin Kazankov Jacob George Henning Gronbæk Department of Hepatology and Gastroenterology Aarhus University HospitalAarhus N DK-8200Denmark Storr Liver Centre Westmead Institute for Medical ResearchWestmead HospitalSydney NSW 2145Australia University of Sydney Sydney NSW 2145Australia

More than five years ago,the treatment of hepatitis C virus infection was revolutionized with the introduction of all-oral direct-acting antiviral(DAA)*** proved highly efficient in curing patients with chronic hepatitis C(CHC),including patients with *** new DAA treatments were alleged to induce significant improvements in clinical outcome and prognosis,but the exact cause of the expected benefit was ***,little was known about how the underlying liver disease would be affected during and after viral *** this review,we describe and discuss the liver-related effects of the new treatments in regards to both pathophysiological aspects,such as macrophage activation,and the time-dependent effects of therapy,with specific emphasis on inflammation,structural liver changes,and liver function,as these factors are all related to morbidity and mortality in CHC *** seems clear that antiviral therapy,especially the achievement of a sustained virologic response has several beneficial effects on liver-related parameters in CHC patients with advanced liver fibrosis or *** seems to be a timedependent effect of DAA therapy with viral clearance and the resolution of liver inflammation followed by more discrete changes in structural liver *** improvements lead to favorable effects on liver function,followed by an improvement in cognitive dysfunction and portal ***,the data provide knowledge on the several beneficial effects of DAA therapy on liverrelated parameters in CHC patients suggesting short-and long-term improvements in the underlying disease with the promise of an improved longterm prognosis.

关键词： Chronic hepatitis C Antiviral treatment Inflammation Liver fibrosis Liver cirrhosis Metabolic liver function Galactose elimination capacity Urea synthesis capacity Portal hypertension Hepatic encephalopathy

Optimization, Spectroscopic(FT-IR, Excited States, UV/Vis) Studies, FMO, ELF, LOL, QTAIM and nBO Analyses and Electronic Properties of Two new Pyrimidine Derivatives

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2019年第10期38卷 1615-1639,1609页

作者： SIYAMAK Shahab MASOOME Sheikhi LIUDMILA Filippovich ZAnnA Ignatovich konstantin Laznev ALEXAnDER Muravsky RADWAn Alnajjar SADEGH Kaviani Belarusian State University I SEI BSUMinskRepublic of Belarus Institute of Physical Organic Chemistry National Academy of Sciences of Belarus13 Surganov Str.Minsk 220072 Institute of Chemistry of new Materials National Academy of Sciences of Belarus36 Skarina Str.Minsk 220141 Young Researchers and Elite Club Gorgan BranchIslamic Azad UniversityGorganIran Department of Chemistry Faculty of ScienceUniversity of BenghaziBenghaziLibya Department of Chemistry University of Cape TownRondebosch 7701South Africa Department of Chemistry Ferdowsi University of MashhadMashhadIran

In the given research,the molecular structures of two new compounds,4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-amine(PM-1)and n-(4-((E)-3-(dimethylamino)styryl)-6-((E)-4-(dimethylamino)styryl)pyrimidine-2-yl)-4,6-dichloro 1,3,5-1,3,5-triazin-2-amine(PM-2),have been studied with the use of density functional theory(DFT/B3LYP/MidiX)in dimethylformamide(DMF)for the first *** electronic spectra of the new compounds in a DMF solvent were carried out by temporally dependent density functional theory(TD-DFT)*** computed absorption spectral data of the title compounds are in good agreement with the experimental data,thus allowing an assignment of the UV/Vis *** equilibrium geometry,the HOMO and LUMO molecular orbitals,excitation energies,oscillator strengths and natural Bond Orbital(nBO)analysis for the molecules have also been calculated and ***-IR spectra of the title molecules are recorded and *** electron location function(ELF),localized orbital locator(LOL)and quantum theory of atoms in molecules(QTAIM)analyses were also carried *** the basis of polyvinyl alcohol(PVA)and synthesized molecules,polarizer for UV/Vis region of the spectrum has been developed.

关键词： pyrimidine DFT UV/Vis spectrum TD-DFT polarization QTAIM analysis

Formation of Rutile nanoparticles from the Condensed Disperse Phase at a Surface of High-Temperature Particles

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science and Engineering 2013年第4期3卷 251-262页

作者： nikolay Kh. Kopyt konstantin Semenov nikolay n. Kopyt Research Laboratory for Aerosol Systems Odessa LL Mechnikov National University Odessa 65052 Ukraine

The photos, which are done by electron microscope, of the condensed disperse phase, surrounding high-temperature metal particles are presented. The dependence of concentration of condensed dispersive phase which surrounds a high-temperature metal particle upon the temperature of the particle was obtained. The dependence of concentration of electrons in condensed dispersive phase upon the temperature of the particle was studied. The dependence of an equilibrium charge of a metal particle surrounded with condensed disperse phase on the temperature of a particle in a positive and negative region is presented. The dependence of a charge of a metal particle on time at the fixed temperature is obtained.

关键词： nanoparticles nanotechnologies particles of the titanium.