检索结果-南通市图书馆

Science China(technological Sciences) 2009年第1期52卷 198-203页

作者： S. SUMAtHI S. BHAtIA k.t. lee A. R. MOHAMED School of Chemical Engineering Engineering Campus Universiti Sains Malaysia 14300 Nibong Tebal Pulau Pinang

this study examined the individual and simultaneous adsorption of SO{in{itx}} (SO{in{it2}}) and NO{in{itx}} (NO-NO{in{it2}}) on activated carbon prepared from waste palm shell. the adsorption process was examined in a fixed bed reactor at low temperatures (100\2-300\dgC). For individual adsorption without any catalytic activation, SO{in{itx}} showed good adsorption whereas NO{in{itx}} was very much poor. In the simultaneous adsorption of SO{in{itx}} and NO{in{itx}}, SO{in{itx}} showed greater adsorption affinity than NO{itx}. For palm shell activated carbon (PSAC) impregnated with metal catalyst (Ni and Ce) the concentration adsorbed profile showed that the amount of SO{in{itx}} adsorbed decreased regularly, while the amount of the adsorbed NO{in{itx}} increased irregularly. the properties of the pure and impregnated PSAC were analyzed by BEt, SEM and EDX. these investigations indicated that PSAC impregnated with metal catalyst is the determining factor in the adsorption of SO{in{itx}} and NO{in{itx}} simultaneously.

关键词： palm shell activated carbon flue gas SO_x NO_x

SOME EXACt SOLUtIONS OF 3-DIMENSIONAL ZERO-PRESSURE GAS DYNAMICS SYStEM

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2011年第6期31卷 2107-2121页

作者： k.t. Joseph Manas R. Sahoo School of Mathematics Tata Institute of Fundamental Research

the 3-dimensional zero-pressure gas dynamics system appears in the modeling for the large scale structure formation in the universe. the aim of this paper is to construct spherically symmetric solutions to the system. the radial component of the velocity and density satisfy a simpler one dimensional problem. First we construct explicit solutions of this one dimensional case with initial and boundary conditions. then we get special radial solutions with different behaviours at the origin.

关键词： zero-pressure gas dynamics spherically symmetric solutions

Mitigation of EDFA transient effects in variable duty cycle pulsed signals

在线全文

学校读者我要写书评

暂无评论

Defence technology（防务技术） 2019年第3期15卷 276-281页

作者： D. Meena k.t. Sarath Fredy Francis E. Dipin t. Srinivas Electronics and Radar Development Establishment (LRDE) DRDO Bangalore Karnataka 560093 India Model Engineering College Thrikkakara Cochin Kerala 682021 India Indian Institute of technology Madras Chennai Tamil Nadu 600036 India

We report the transient effects in Erbium Doped Fiber Amplifier (EDFA) systems for pulsed signals with different duty-cycles. the work includes the analysis using three different duty-cycles, 10%, 20% and 50%. A curve fitting technique is also proposed to predict the transients of any lesser duty-cycled pulse, once the transients of a larger duty-cycled pulse is known. Mathematical evaluation confirms the double exponential shape of transient distorted signal. Further, EDFA transient effect is experimentally verified on a Wavelength Division Multiplexed (WDM) link by multiplexing high and low bitrate modulated optical signals. We conclude the paper by proposing a transient suppression technique for variable dutycycle signals and analyzing its effectiveness with different wavelength spacing.

关键词： EDFA transients WDM Variable duty cycle Suppression

An enhanced cosine-based visual technique for the robust tweets data clustering

在线全文

学校读者我要写书评

暂无评论

International Journal of Intelligent Computing and Cybernetics 2021年第2期14卷 170-184页

作者： Narasimhulu k. Meena Abarna k.t. Sivakumar B. Annamalai University ChidambaramIndiaand Rajeev Gandhi Memorial College of Engineering and technology NandyalIndia

Purpose-the purpose of the paper is to study multiple viewpoints which are required to access the more informative similarity features among the tweets documents,which is useful for achieving the robust tweets data clustering ***/methodology/approach-Let“N”be the number of tweets documents for the topics *** texts,punctuations and other symbols are removed,tokenization and stemming operations are performed in the initial tweets pre-processing ***-of-features are determined for the tweets;later tweets are modelled with the obtained bag-of-features during the process of topics *** of topics features are extracted for every tweet *** set of topics features of N documents are treated as *** key idea of the proposed work is to use multi-viewpoints in the similarity features *** following figure illustrates multi-viewpoints based cosine similarity computation of the five tweets documents(here N 55)and corresponding documents are defined in projected space with five viewpoints,say,v_(1),v_(2),v_(3),v4,and *** example,similarity features between two documents(viewpoints v_(1),and v_(2))are computed concerning the other three multi-viewpoints(v_(3),v4,and v5),unlike a single viewpoint in traditional cosine ***-Healthcare problems with tweets *** models play a crucial role in the classification of health-related tweets with finding topics(or health clusters)instead of finding term frequency and inverse document frequency(tF-IDF)for unlabelled ***/value-topic models play a crucial role in the classification of health-related tweets with finding topics(or health clusters)instead of finding tF-IDF for unlabelled tweets.

关键词： tweets data clustering topic models tF-IDF Similarity features Visual technique VAt cVAt MVCS-VAt

Generation of brain vascular heterogeneity:recent advances from the perspective of angiogenesis

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

Neural Regeneration Research 2025年第7期20卷 2013-2014页

作者： Nathanael J.lee Ryota L.Matsuoka Department of Neurosciences Lerner Research InstituteCleveland ClinicClevelandOHUSA Department of Molecular Medicine Cleveland Clinic Lerner College of MedicineCase Western Reserve UniversityClevelandOHUSA

Heterogeneous proper t i es of vascular endothelial cells in the brain:the brain displays large energy dynamics and consumption,and this high level of metabolic demands is fulfilled by a continuous supply of glucose and oxygen through its vascular *** vasculature consists of highly divergent blood vessel branches,giving rise to a dense network of capillaries that supply blood to all cells across the *** elaborated vascular network is thought to develop via angiogenesis,a process in which new blood vessels grow from pre-existing *** capillaries exhibit organotypic features distinct from other tissues and are formed primarily by two major endothelial cell(EC)types:those that form the semi-permeable blood-brain barrier(BBB)and those that develop highly permeable pores known as fenestrae(Matsuoka et al.,2022).the structural and functional differences between BBB and fenestrated vascular ECs represent a fundamental feature of brain vasculature and form the foundation for both brain function and homeostasis.

关键词： angiogenesis homeostasis network

Model with strong γ_4 t-violation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2008年第12期32卷 939-944页

作者： R. Friedberg t. D. lee Physics Department Columbia University New York NY 10027 U.S.A. China Center of Advanced Science and technology (CCASt/World Lab.) P.O. Box 8730

eAbstract We extend the t violating model of the paper on ＂Hidden symmetry of the CkM and neutrinomapping matrices＂ by assuming its t-violating phases X↑ and X↓ to be large and the same, with X = X↑ = X↓. In this case, the model has 9 real parameters： at, α↑,β↑,ξ↑,η↑t for the t-quark sector, α↓,β↓,ξ↓,η↓, for the sector and a common X- We examine whether these nine parameters are compatible with ten observables： the six quark masses and the four real parameters that characterize the CkM matrix （i.e., the Jarlskog invariant and three Eulerian angles）. We find that this is possible only if the t violating phase X is large, between -120^o to -135^o. In this strong t violating model, the smallness of theJarlskog invariant 3 × 10^-5 ismainly accounted for by the large heavy quark masses, with mc/mt〈ms/mb≈0.02, as well as the near completeoverlap of t and b quark, with （c｜b）=-0.04.

关键词： Jarlskog invariant CkM matrix strong γ4 t-violation

Structural,magnetic,and acidic properties of cobalt ferrite nanoparticles synthesised by wet chemical methods

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2015年第3期4卷 199-205页

作者： Manju kURIAN Smitha tHANkACHAN Divya S.NAIR Aswathy E.k. Aswathy BABU Arathy tHOMAS Binu kRISHNA k.t. Department of Chemistry Mar Athanasius CollegeKothamangalam-686666India Department of Physics Mar Athanasius CollegeKothamangalam-686666India

A detailed investigation on the effect of preparation method on the structural,magnetic,and acidic properties of cobalt ferrite nanoparticles prepared by sol-gel and co-precipitation is *** acid and ethylene glycol were used as gelling agents,while sodium hydroxide and aqueous ammonia were used as precipitating *** resulting ferrites were calcined at 450℃ and 750℃.Sharper X-ray diffraction(XRD)peaks were observed for the samples calcined at 750℃,indicating greater crystallinity of the samples calcined at higher *** crystallite sizes fell in the ranges of 7.1-21.1 nm and 30.4-42.1 nm for the samples calcined at 450℃ and 750℃,*** infrared spectra revealed two main absorption bands,the high frequency bandν1 around 600 cm^(-1) and the low frequency bandν2 around 400 cm^(-1) arising from stretching vibrations of the oxygen bond with the metal in the tetrahedral(A)and octahedral(B)sites in the spinel *** of particles was observed in the scanning electron microscopy(SEM)*** parameters of CoFe_(2)O_(4) nanoparticles greatly depended on calcination temperature and preparation *** temperature programmed desorption(tPD)measurements indicated that weak acid sites predominate medium strength sites,while the number of strong acid sites is the *** acidity decreased for the samples calcined at higher *** results underline the effect of preparation conditions on the morphology,crystallite size,and magnetic properties of nano ferrites.

关键词： nano ferrites sol-gel technique co-precipitation magnetic property surface acidity

Effect of thermal Refining on Mechanical Properties of Annealed SAE 4130 by Multilayer GtAW

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 Iron and Steel Research International 2012年第7期19卷 71-78页

作者： I k lee C L Chung Y t lee Y t Chien Department of Materials Science and Engineering Da-Yeh University

During the first welding process in manufacturing a precise seam container, the steel material must first undergo a full annealing treatment. Multilayer welding operations are conducted and then applied with refining treatment to obtain the goal by hardening. the influence of thermal refining on mechanical properties of annealed SAE 4130 by multilayer GtAW （gas tungsten arc welding） was discussed. the AW （annealing＋welding） and AWSt （annealing＋welding＋solution＋tempering） occurred with a minimum hardness value at GGHAZ （grain growth heat affected zone） due to coarse grain growth~ the hardness occurred with sudden drops between the multilayer welding, but was still larger than the minimum value at HAZ （heat affected zone）. the welded joint efficiency of the AWSt was 89.9%, with the elongation reduced to 77.2% of ASt （annealing＋solution＋tempering）. the cross section of the tensile samples both appeared with a uniform dimple-shaped structure, and however the necking for ASt was greater than that for AWSt. the impact value for AWSt was 166.5% of ASt. Moreover, from microstructure observations, it was found that AWSt had a greater tendency to ductile failure than ASt. these results can be inferred., the process of steady pressure and the initial position of the precision tube breakage HAZ. However, when stress occurs instantly, HAZ can absorb more energy, therefore the initial damage does not occur.

关键词： thermal refining SAE 4130 multilayer welding GtAW

Crystallization and impact history of a meteoritic sample of early lunar crust(NWA 3163)refined by atom probe geochronology

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第5期10卷 1841-1848页

作者： L.F. White D.E. Moser k.t. tait B. Langelier I. Barker J.R. Darling Centre for Applied Planetary Mineralogy Department of Natural HistoryRoyal Ontario MuseumTorontoOntarioM5S 2C6Canada Department of Earth Sciences University of TorontoTorontoOntarioM5S 3B1Canada Department of Earth Sciences University of Western OntarioLondonN6A 5B7Canada Canadian Centre for Electron Microscopy McMaster UniversityHamiltonOntarioCanada School of Earth and Environmental Science University of PortsmouthPortsmouthUK

Granulitic lunar meteorites offer rare insights into the timing and nature of igneous,metamorphic and impact processes in the lunar *** dating the different events recorded by these materials is very challenging,however,due to low trace element abundances (***,Nd,Lu,Hf),rare micrometerscale U-th-bearing accessory minerals,and disturbed Ar-Ar systematics following a multi-stage history of shock and thermal *** we report on micro-baddeleyite grains in granulitic mafic breccia NWA 3163 for the first time and show that targeted microstructural analysis (electron backscatter diffraction) and nanoscale geochronology (atom probe tomography) can overcome these barriers to lunar chronology.A twinned (-90°/) baddeleyite domain yields a 232th/208Pb age of 4328 ± 309 Ma,which overlaps with a robust secondary ion mass spectrometry (SIMS) 207Pb/206Pb age of 4308± 18.6 Ma and is interpreted here as the crystallization age for the igneous protolith of NWA 3163.A second microstructural domain,th,contains patchy overprinting baddeleyite and yields a th-Pb age of 2175± 143 Ma,interpreted as dating the last substantial impact event to affect the *** finding demonstrates the potential of combining microstructural characterization with nanoscale geochronology when resolving complex P-t-t histories in planetary materials,here yielding the oldest measured crystallization age for components of lunar granulite NWA 3163 and placing further constraints on the formation and evolution of lunar crust.

关键词： Baddeleyite U-th-Pb isotopes EBSD Atom probe tomography Geochronology Northwest Africa 3163

Inhibitory actions of mibefradil on steroidogenesis in mouse Leydig cells： involvement of Ca^2＋ entry via the t-type Ca^2＋ channel

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2010年第6期12卷 807-813页

作者： Jae-Ho lee Jong-Uk kim Changhoon kim Churl k. Min Institute of tissue Regeneration Engineering Dankook University Cheonan 330714 South Korea Department of Molecular Sciences and technology Ajou University Suwon 443749 South Korea Division of Cardiology Department of Medicine Emory University Atlanta GA 30322 USA Department of Biological Sciences Aj ou University Suwon 443749 South Korea

Intracellular cAMP and Ca^2＋ are involved in the regulation of steroidogenic activity in Leydig cells, which coordinate responses to luteinizing hormone （LH） and human ehorionic gonadotropin （hCG）. However, the identification of Ca^2＋ entry implicated in Leydig cell steroidogenesis is not well defined. the objective of this study was to identify the type of Ca^2＋ channel that affects Leydig cell steroidogenesis. In vitro steroidogenesis in the freshly dissociated Leydig cells of mice was induced by hCG incubation. the effects of mibefradil （a putative t-type Ca^2＋ channel blocker） on steroidogenesis were assessed using reverse transcription （Rt）-polymerase chain reaction analysis for the steroidogenic acute regulatory protein （StAR） mRNA expression and testosterone production using radioimmunoassay. In the presence of 1.0 mmol L-1 extracellular Ca^2＋, hCG at 1 to 100 IU noticeably elevated both StAR mRNA level and testosterone secretion （P 〈 0.05）, and the stimulatory effects of hCG were markedly diminished by mibefradil in a dose-dependent manner （P 〈 0.05）. Moreover; the hCG-induced increase in testosterone production was completely removed when external Ca^2＋ was omitted, implying that Ca entry is needed for hCG-induced steroidogenesis. Furthermore, a patch-clamp study revealed the presence of mibefradil-sensitive Ca^24- currents seen at a concentration range that nearly paralleled those inhibiting steroidogenesis. Collectively, Our data provide evidence that hCG-stimulated steroidogenesis is mediated at least in part by Ca^2＋ entry carried out by the t-type Ca^2＋ channel in the Leydig cells of mice.

关键词： Leydig cells mibefradil StAR steroidogenesis t-type Ca^2+ channel