检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

communications in theoretical Physics 2010年第3期53卷 575-578页

作者： K. Fakhar t. Hayat cheng Yi N. Amin Department of Mathematics Faculty of Science Universiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia Department of Mathematics Universily of Science and technology of china Hefei Anhui 230026 China

this note looks at the two similarity solutions of the Navier-Stokes equations in polar coordinates. In the second solution an initial value problem is reduced into generalized stationary KDV and hence integrable.

关键词： Navier Stokes equation symmetry solutions stationary I4DV

Microstructural evolution of Infrared Brazed cP-ti Using ti-cu-Ni Brazes

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2011年第2期27卷 131-138页

作者： c.t.chang t.Y.Yeh R.K.Shiue c.S.chang Department of Mechanical engineering National Hualien Industrial Vocational Senior High SchoolHualien 970TaiwanChina Department of Materials Science and engineering National Taiwan UniversityTaipei 106TaiwanChina engineered Materials Solutions 39 Perry AvenueMS 4-1AttleboroMA 02703-2410USA

Microstructural evolution of infrared vacuum brazed cP-ti using two ti-based braze alloys,ti-15cu-15Ni and ti-15cu-25Ni,has been *** infrared brazed joint consisted of eutectic ti 2 cu/ti 2 Ni intermetallic compounds and ti-rich *** eutectic ti 2 cu/ti 2 Ni intermetallic compounds disappeared from the joint after being annealed at 900 c for 1 *** contrast,the depletion rate of both cu and Ni from the braze alloy into cP-ti substrate at 750 c annealing was greatly decreased as compared with that annealed at 900 *** ti 2 cu/ti 2 Ni phases were observed even if the specimen was annealed at 750 c for 15 *** the Ni content of the ti-15cu-25Ni braze alloy is much higher than that of the ti-15cu-15Ni alloy,the amount of eutectic ti 2 cu/ti 2 Ni phases in ti-15cu-25Ni brazed joint is more than that in ti-15ci-15Ni brazed ***,similar microstructural evolution can be obtained from the infrared brazed joint annealed at various temperatures and/or time for both filler metals.

关键词： Infrared Brazing cP-ti ti-cu-Ni fillers Microstructure

Féeton(B-L gauge boson)dark matter for the 511-keV gamma-ray excess and the prediction of low-energy neutrino flux

在线全文

学校读者我要写书评

暂无评论

chinese Physics c 2024年第8期48卷 76-82页

作者： Jie Sheng Yu cheng Weikang Lin tsutomu t.Yanagida tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityChina Key Laboratory for Particle Astrophysics and cosmology(MOe)&Shanghai Key Laboratory for Particle Physics and cosmology Shanghai Jiao Tong UniversityShanghai 200240China South-Western Institute For Astronomy Research Yunnan UniversityKunming 650500China Kavli IPMU(WPI) UTIASUniversity of TokyoKashiwa277-8583Japan

the féeton is the gauge boson of the U(1)_(B−L) gauge *** the gauge coupling constant is extremely small,the féeton becomes a candidate for dark *** show that its decay to a pair of an electron and a positron explains the observed Galactic 511-keV gamma-ray excess in a consistent *** féeton dark matter decays mainly into pairs neutrino and *** low-energy experiments with improved directional capability will enable capturing these neutrino *** seesaw-motivated parameter space predicts a relatively short féeton lifetime that is comparable to the current cosmological constraint.

关键词： feeton 511-keV gamma-ray excess low-energy neutrino

evaluation of hydrogeochemical characteristics of groundwater in parts of the lower Benue trough,Nigeria

在线全文

学校读者我要写书评

暂无评论

chinese Journal Of Geochemistry 2010年第4期29卷 398-406页

作者： Nganje t.N. Adamu c.I. Ugbaja A.N. Amah A.e. Department of Geology University of Calabar

the aim of this work is to evaluate the hydrogeochemical characteristics of groundwater in parts of the lower Benue through in Nigeria as well as to evaluate the variation in groundwater chemistry data and the suitability of the groundwater for drinking and other domestic *** was based on chemical analyses of 44 water samples from existing wells and boreholes in the study *** the statistical analysis(wide ranges,median and standard deviation),it is obvious that there are significant variations in the quality/composition of groundwater in the period of *** calculated SAR,Na% and RSc values indicated that the water is of excellent to good quality and is suitable for *** and HcO3 are dominant with respect to the chemical composition of the *** the basis of water chemistry,hydrochemical indices and factor analysis the dominant controls or processes affecting the distribution of geochemical variables in the study area have been shown to be water/rock interaction which is mainly controlled by carbonate and silicate dissolution as well as anthropogenic influence to a lesser *** processes include cation exchange reactions and reverse ion exchange to a minor extent.

关键词：水文地球化学特征饮用地下水尼日利亚离子交换反应水化学指标海槽评价特别行政区

Raman Spectroscopy of Garnet-group Minerals

在线全文

学校读者我要写书评

暂无评论

chinese Journal Of Geochemistry 1994年第2期13卷 176-183页

作者：彭明生李迪恩 H.K.MAO e.c.t.cHAO Division of Quantum Mineralogy Department of Geology Central University of Technology Changsha China Geophysical Laboratory Carnegie Institution of Washington Washington D.C. USA U. S. Geological Survey 959 National Center Reston Virginia USA

the Raman spectra of the natural end members of the garnet-group minerals, which include pyrope, almandine and spessarite of Fe-Al garnet series and grossularite, andradite and uvarovite of ca-Fe garnet series, have been studied. Measured Raman spectra of these minerals are reasonably and qualitatively assigned to the intemal modes, translational and rotatory modes of SiO4 tetrahedra,as well as the translational motion of bivalent cations in the X site. the stretch and rotatory Alg modes for the Fe-Al garnet series show obvious Raman shifts as compared with those for the ca-Fe garnet series, owing to the cations residing in the X site connected with SiO4 tetrahedra by sharing the two edges. the Raman shifts of all members within either of the series are attributed mainly to the properties of cations in the X site for the Fe-Al garnet series and in the Y site for the ca-Fe gamet series.

关键词：拉曼光谱石榴石榴子石铁铝榴石晶体结构

emissions from the combustion of eucalypt and pine chips in a fluidized bed reactor

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2016年第4期28卷 246-258页

作者： e.D.Vicente L.A.c.tarelho e.R.teixeira M.Duarte t.Nunes c.colombi V.Gianelle G.O.da Rocha A.Sanchez de la campa c.A.Alves centre for environmental and Marine Studies Department of Environment and PlanningUniversity of Aveiro Regional centre for Air Quality Monitoring Environmental Monitoring Sector ARPA Federal University of Bahia Chemical Institute40170-290Campus de Ondina centre for Research in Sustainable chemistry (cIQSO) Joint Research Unit to CSIC "Atmospheric Pollution"University of HuelvaCampus El Carmen

Interest in renewable energy sources has increased in recent years due to environmental concerns about global warming and air pollution,reduced costs and improved efficiency of *** the european Union（eU）energy directive,biomass is a suitable renewable *** aim of this study was to experimentally quantify and characterize the emission of particulate matter（PM（2.5））resulting from the combustion of two biomass fuels（chipped residual biomass from pine and eucalypt）,in a pilot-scale bubbling fluidized bed（BFB）combustor under distinct operating *** variables evaluated were the stoichiometry and,in the case of eucalypt,the leaching of the *** cO and PM（2.5）emission factors were lower when the stoichiometry used in the experiments was higher（0.33±0.1 g cO/kg and 16.8±1.0 mg PM（2.5）/kg,dry gases）.the treatment of the fuel by leaching before its combustion has shown to promote higher PM（2.5）emissions（55.2±2.5 mg/kg,as burned）.Organic and elemental carbon represented 3.1 to 30 wt.% of the particle mass,while carbonate（cO3^（2-））accounted for between 2.3 and 8.5 wt.%.the particulate mass was mainly composed of inorganic matter（71% to 86% of the PM（2.5）mass）.compared to residential stoves,BFB combustion generated very high mass fractions of inorganic *** was the water soluble ion in higher concentration in the PM（2.5）emitted by the combustion of eucalypt,while calcium was the dominant water soluble ion in the case of pine.

关键词： Biomass combustion Fluidized bed PM2.5emissions chemical composition

Structural modeling of sandwich structures with lightweight cellular cores

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2007年第5期23卷 545-559页

作者： t.Liu Z.c.Deng t.J.Lu Department of engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China MOe Key Laboratory of Strength and Vibration School of AerospaceXi'an Jiaotong UniversityXi'an 710049China

An effective single layered finite element （Fe） computational model is proposed to predict the structural behavior of lightweight sandwich panels having two dimensional （2D） prismatic or three dimensional （3D） truss cores. three different types of cellular core topology are considered： pyramidal truss core （3D）, Kagome truss core （3D） and corrugated core （2D）, representing three kinds of material anisotropy： orthotropic, monoclinic and general anisotropic. A homogenization technique is developed to obtain the homogenized macroscopic stiffness properties of the cellular core. In comparison with the results obtained by using detailed Fe model, the single layered computational model can give acceptable predictions for both the static and dynamic behaviors of orthotropic truss core sandwich panels. However, for non-orthotropic 3D truss cores, the predictions are not so well. For both static and dynamic behaviors of a 2D corrugated core sandwich panel, the predictions derived by the single layered computational model is generally acceptable when the size of the unit cell varies within a certain range, with the predictions for moderately strong or strong corrugated cores more accurate than those for weak cores.

关键词： cellular material Sandwich panel Homogenization Finite element

Geometry-based mass grading of mango fruits using image processing

在线全文

学校读者我要写书评

暂无评论

Information Processing in Agriculture 2017年第2期4卷 150-160页

作者： M.A.Momin M.t.Rahman M.S.Sultana c.Igathinathane A.t.M.Ziauddin t.e.Grift Department of Farm Power and Machinery Bangladesh Agricultural UniversityMymensingh 2202Bangladesh Department of Agricultural and Biosystems engineering North Dakota State University1221 Albrecht BoulevardFargoND 58102USA Department of Agricultural and Biological engineering University of Illinois at Urbana-ChampaignUrbanaILUSA

Mango(Mangifera indica)is an important,and popular fruit in ***,the post-harvest processing of it is still mostly performed manually,a situation far from satisfactory,in terms of accuracy and *** automate the grading of mangos(geometry and shape),we developed an image acquisition and processing system to extract projected area,perimeter,and roundness *** this system,images were acquired using a XGA format color camera of 8-bit gray levels using fluorescent *** image processing algorithm based on region based global thresholding color binarization,combined with median filter and morphological analysis was developed to classify mangos into one of three mass grades such as large,medium,and *** system achieved an accuracy of 97% for projected area and Feret diameter,79% for perimeter,and 36% for *** achieve a finer grading,two different grading features could be used in *** image grading system is simple and efficient and can be considered a suitable first stage to mechanizing the commercial grading of mangos in ***,the method has the potential to be applied to other crops with suitable adjustments.

关键词： Horticultural crops Quality Sorting

Does supplier concentration matter to investors during the cOV1D-19 crisis:evidence from china?

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

Financial Innovation 2022年第1期8卷 2289-2316页

作者： Louis t.W.cheng Jack S.c.Poon Shaolong tang Jacqueline Wenjie Wang School of Business The Hang Seng University of Hong KongHong KongChina School of Accounting and Finance of the Hong Kong Polytechnic University Hong KongChina Division of Business and Management Beijing Normal University-Hong Kong Baptist UniversityUnited International CollegeZhuhaiChina

the literature shows that investor attention to customer–supplier disclosure increases when suppliers’information arrival is *** to the widespread of city lockdowns in china and the implementation of social distancing to control the cOVID-19 pandemic,investor attention to potential disruption of the supply chain spikes,leading to a price devaluation for firms with high supplier concentration *** find that a higher degree of supplier concentration is related to more serious stock price declines over the short-term and medium-term windows right after the Wuhan *** result lends support to the argument that the concentration risk of suppliers is a significant consideration for china stock market investors,especially under the potential financial distress at the firm level induced by the cOVID-19 crisis.

关键词： cOVID-19 Supplier concentration Supplier disclosure Stock price effect Industry neutral portfolio