检索结果-南通市图书馆

η-production on the proton via electromagnetic and hadronic probes

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2009年第12期33卷 1175-1182页

作者： B. Saghai j. Durand B. julia-Diaz 何军 t.-S. H. Lee t. Sato Institut de Recheche sur les lois Fondamentales de l’Univers DSM/Irfu CEA-Saclay 91191 Gif-sur-Yvette France 2. Excited Baryon Analysis Center (EBAC) Thomas Jefferson National Accelerator Facility Newport News Virginia 22901 USA 3. Departament d'Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos Universitat de Barcelona E-08028 Barcelona Spain 4. Institute of Modern Physics Chinese Academy of Sciences physics Division Argonne National Laboratory Argonne Illinois 60439 USA Department of physics Osaka University Toyonaka Osaka 560-0043 Japan

the reactions π-p→ηn and γp→ηp are investigated within a dynamical coupled-channels model of meson production reactions in the nucleon resonance region. the meson-baryon channels included are πN, ηN, π-, σN, and ρN. the direct η-photoproduction process is studied within a formalism based on a chiral constituent quark model approach, complemented with a one-gluon-exchange mechanism, to take into account the breakdown of the SU(6)O(3) symmetry. In the models search, the following known nucleon resonances are embodied: S11(1535), S11(1650), p11(1440), p11(1710), p13(1720), D13(1520), D13(1700), D15(1675), and F15(1680). Data for the π-p→ηn reaction from threshold up to a total center-of-mass energy of W ≈ 2 GeV are satisfactorily reproduced. For the photoproduction channel, two additional higher mass known resonances, p13(1900) and F15(2000), are also considered. However, reproducing the data for γp→ηp requires, within our approach, two new nucleon resonances, for which we extract mass and width.

关键词： multichannel scattering meson production baryon resonances

Magnetocaloric effect in ErNi2 melt-spun ribbons

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 Rare Earths 2020年第6期38卷 612-616页

作者： j.L.Sanchez Llamazares p.Ibarra-Gaytan C.F.Sanchez-Valdes D.Rlos-jara p.Alvarez-Alonso Instituto potosino de Investigacion Ciendfica y tecnoldgica A.C. Camino a la Presa San Jose 2055Col.Lomas 4San Luis Potosi.S.LP.78216Mexico CpM-tIp University Pavol Jozef SafarikPark Angelinum 9.04154 KosiceSlovakia Division Multidisciplinaria Ciudad UniversitariaUniversidad Aurdnoma de Ciudad Juarez(UACJ)Calle Jose de Jesus Macias Delgado#18100Ciudad Juarez 32579Chihuahua.Mexico Departamento de Fisica Universidad de OviedoCalvo Sotelo s/n33007 OviedoSpain

ErNi2 ribbons were produced by rapid solidification using the melt spinning *** structural,magnetic and magnetocaloric properties in the as-solidified state were studied by X-ray diffraction,scanning electron microscopy,magnetization and specific heat *** are single phase with the MgCu2-type crystal structure,a Curie temperature tC of 6.8 K and a saturation magnetization at2 K and 5 t of 124.0 A·m2/*** a magnetic field change μ0△H of 5 t(2 t) ribbons show a maximum magnetic entropy change |△SMpeak| of 24.1(16.9) j/(kg·K),and an adiabatic temperature change △tadmax of8.1(4.4) K;this is similar to the previously reported literature for bulk alloys that were processed through conventional melting techniques followed by prolonged thermal *** addition,the samples also show slightly wider △SM(t) curves with respect to bulk alloys leading to a larger refrigerant capacity.

关键词： ErNi2 Laves phase Melt-spun ribbons Magnetic entropy change Adiabatic temperature change Rare Earths

Charmed baryon resonances with heavy-quark symmetry

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2009年第12期33卷 1323-1326页

作者： L. tolos C. Garcia-Recio V. K. Magas t. Mizutani j. Nieves A. Ramos L. L. Salcedo theory Group KVI University of Groningen Zernikelaan 25 9747 AA Groningen The Netherlands Departamento de Física Atómica Molecular y Nuclear Universidad de Granada E-18071 Granada Spain Departament d'Estructura i Constituents de la matèria and Institut de Ciències del Cosmos Universitat de Barcelona E-08028 Barcelona Spain Department of physics Virginia Polytechnic Institute and State University Blacksburg VA 24061 USA Instituto de Física Corpuscular (centro mixto CSIC-UV) Institutos de Investigación de Paterna Aptdo. 22085 E-46071 Valencia Spain

We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as Ac（2595）, Ac（2660）, Ec（2902） or Ac（2941）, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU（4） schemes.

关键词： charmed baryon resonances heavy-quark symmetry SU(8) and SU(4) spin-flavor symmetry

targets for high repetition rate laser facilities:needs,challenges and perspectives

在线全文

学校读者我要写书评

暂无评论

High power Laser Science and Engineering 2017年第3期5卷 10-40页

作者： I.prencipe j.Fuchs S.pascarelli D.W.Schumacher R.B.Stephens N.B.Alexander R.Briggs M.Büscher M.O.Cernaianu A.Choukourov M.De Marco A.Erbe j.Fassbender G.Fiquet p.Fitzsimmons C.Gheorghiu j.Hund L.G.Huang M.Harmand N.j.Hartley A.Irman t.Kluge Z.Konopkova S.Kraft D.Kraus V.Leca D.Margarone j.Metzkes K.Nagai W.Nazarov p.Lutoslawski D.papp M.passoni A.pelka j.p.perin j.Schulz M.Smid C.Spindloe S.Steinke R.torchio C.Vass t.Wiste R.Zaffino K.Zeil t.tschentscher U.Schramm t.E.Cowan Lawrence Berkeley National Laboratory USA 25Institute of Microelectronics of Barcelona National Center of Microelectronic Spanish Research Council Spain 26University of St. Andrews UK

A number of laser facilities coming online all over the world promise the capability of high-power laser experiments with shot repetition rates between 1 and 10 Hz. target availability and technical issues related to the interaction environment could become a bottleneck for the exploitation of such facilities. In this paper, we report on target needs for three different classes of experiments: dynamic compression physics, electron transport and isochoric heating, and laser-driven particle and radiation sources. We also review some of the most challenging issues in target fabrication and high repetition rate operation. Finally, we discuss current target supply strategies and future perspectives to establish a sustainable target provision infrastructure for advanced laser facilities.

关键词： high-energy density physics target design and fabrication

EStImatION OF A SOURCE tERM IN A QUASI StEADY tWO-DIMENSIONAL HEAt tRANSFER pROBLEM: AppLICAtION tO AN ELECtRON BEAM WELDING

在线全文

学校读者我要写书评

暂无评论

ESTIMATION OF A SOURCE TERM IN A QUASI STEADY TWO-DIMENSIONA...

Habitat specialization and phylogenetic structure of tree species in a coastal Brazilian white-sand forest

湖北省暨武汉焊接学会成立二十五周年2005年焊接学术年会

作者： p．Le Masson E.Artioukhine t．Loulou p．Rogeon M．Carin M．Dumons j．Costa LEt2E/EtM:Laboratoire d’Etudes thermique Energétique et Environnement／Equipe thermophysique et matériaux.Université de Bretagne Sud Institut FEMtO-St Centre Energétique Environnement．Ecole des Mines d’Albi

In the previous work [1], we have analyzed the feasibility of the estimation for a source term S(x, z,t) in a transversal section. the present study is concerned with a two-dimensional inverse phase change problem. the goal is the estimation of the dissipated heat flux in the liquid zone (reconstruction of a source term in the energy equation) from experimentally measured temperatures in the solid zone. this work has an application in the electron beam welding of steels of thickness about 8 cm. the direct thermo-metallurgical problem is treated in a quasi steady two-dimensional longitudinal section (x,y). the beam displacement is normally in the y direction. But in the quasi steady simulation, the beam is steady in the study section. the sample is divided in the axial direction Z in few sections. At each section, a source term is defined with a part of the beam and creates a vaporized zone and a fused zone. the goal of this work is the rebuilding of the complete source term with the estimations at each section. In this paper we analyze the feasibility of the estimation. For this work, we use only the simulated measurements without noise.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

journal of plant Ecology 2014年第2期7卷 134-144页

作者： Alexandre A.de Oliveira Alberto Vicentini jerome Chave Camila de t.Castanho Stuart j.Davies Adriana M.Z.Martini Renato A.F.Lima Ricardo R.Ribeiro Amaia Iribar Vinicius C.Souza Instituto de Biociências Universidade de São PauloRua do Matão321Travessa 14São PauloSP 0550890Brazil Instituto Nacional de pesquisas da Amazônia Av.AndréAraújo2936CP 478.ManausAM 69060001Brazil Evolution et DiversitéBiologique Bâtiment 4R1 UniversitéPaul Sabatier118 route de Narbonne31062 ToulouseFrance Smithsonian tropical Research Institute PO Box 37012WashingtonDC 20013-7012USA ESALQ Universidade de São Paulo.Avenida Pádua Dias11PiracicabaSP 13418900Brazil

Aims the coastal Brazilian rainforest on white-sand(restinga)ranks among the most fragmented forest types in the tropics,owing to both the patchy distribution of sandy soils and widespread coastal development *** we study the environmental and evolutionary determinants of a forest tree assemblage at a single restinga forest in Southeastern *** also explore the ability of competing hypotheses to explain the maintenance of species diversity in this forest type,which includes contrasting extremes of edaphic conditions associated with flooding *** the study was conducted in a white-sand forest permanent plot of 10.24 ha on the coastal plain of Southeastern *** plot was divided into 256 quadrats of 20×20 m,which were classified into two main edaphic habitats(flooded and drained).trees with a diameter≥1 cm at breast height were *** assembled DNA sequence data for each of the 116 morphospecies recognized using two chloroplast markers(rbcL and matK).A phylogenetic tree was obtained using the maximum likelihood method,and a phylogenetic distance matrix was produced from an ultrametric *** analyzed similarity in floristic composition and structure between habitats and related them to cross-plot distances using permutation *** model torus shift simulations were performed to obtain a statistical significance level for habitat association for each *** phylogenetic structure for the two habitats and for each 20×20 m quadrat was calculated using the mean phylogenetic distance weighted by species abundance and checked for significance using the standardized effect size generated by 5000 randomizations of phylogenetic tip *** Findings Our results indicate that partitioning among edaphic habitats is important for explaining species distributions and coexistence in restinga *** distributions within the plot were found to be non-random:there was greater floristic similarity within than betwe

关键词： habitat association torus-translation test phylogenetic community structure niche partitioning edaphic condition

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

透明蓝宝石高压相平衡池及其应用

石油化工 1989年第10期18卷 681-684页

作者：高光华 j.L.Daridon H.Saint-Guirons p.Xans 清华大学化学工程系 Laboratoire de physique des matériaux Industriels

主要描述了全透明高压相平衡池。该池全部用人造蓝宝石制造,其最大工作压力为50Mpa,工作温度为20—200℃。应用该装置,可以目测混合物的相态变化和测定 p-V-t 关系。本文还就 CH_4-C_(16)H_(34)二元体系汽液相界的测定具体阐明其应用。

关键词：蓝宝石相平衡池高压相平衡

Human adipose derived stem cells are superior to human osteoblasts (HOB) in bone tissue engineering on a collagen-fibroin-ELR blend

在线全文

学校读者我要写书评

暂无评论

Bioactive materials 2017年第2期2卷 71-81页

作者： Esen Sayin Rosti Hama Rashid joséCarlos Rodríguez-Cabello Ahmed Elsheikh Erkan türker Baran Vasif Hasirci MEtU Department of BiotechnologyAnkaraTurkey BIOmatEN METU Center of Excellence in Biomaterials and Tissue EngineeringDumlupinar Blvd No:106800 AnkaraTurkey University of Liverpool School of EngineeringL693GH LiverpoolUK BIOFORGE CIBER-BBNCampus“Miguel Delibes”Edificio LUCIAUniversidad de ValladolidPaseo Belen 1947011 ValladolidSpain MEtU Department of Biological SciencesAnkara06800Turkey

the ultrastructure of the bone provides a unique mechanical strength against compressive, torsional andtensional stresses. An elastin-like recombinamer (ELR) with a nucleation sequence for hydroxyapatitewas incorporated into films prepared from a collagen-silk fibroin blend carrying microchannel patternsto stimulate anisotropic osteogenesis. SEM and fluorescence microscopy showed the alignment ofadipose-derived stem cells (ADSCs) and the human osteoblasts (HOBs) on the ridges and in the groovesof microchannel patterned collagen-fibroin-ELR blend films. the Young's modulus and the ultimatetensile strength (UtS) of untreated films were 0.58 ± 0.13 Mpa and 0.18 ± 0.05 Mpa, respectively. After 28days of cell culture, ADSC seeded film had a Young's modulus of 1.21 ± 0.42 Mpa and UtS of0.32 ± 0.15 Mpa which were about 3 fold higher than HOB seeded films. the difference in Young'smodulus was statistically significant (p: 0.02). ADSCs attached, proliferated and mineralized better thanthe HOBs. In the light of these results, ADSCs served as a better cell source than HOBs for bone tissueengineering of collagen-fibroin-ELR based constructs used in this study. We have thus shown theenhancement in the tensile mechanical properties of the bone tissue engineered scaffolds by usingADSCs.

关键词： Adipose-derived stem cells Human osteoblasts tissue engineering Bone Mechanical properties

Synthesis and optical properties of nanosized CdS prepared in a quaternary CtAB/n-hexanol/n-heptane/water reverse micelle

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

Chinese Science Bulletin 2001年第22期46卷 1873-1877页

作者： Zhang, j Sun, LD Qian, C Liao, CS Yan, CH peking Univ PKU HKU Joint Lab Rare Earth Mat & Bioinorgan Chem State Key Lab Rare Earth Mat Chem & Applicat Beijing 100871 Peoples R China

Quaternary water-in-oil reverse micelles consisting of cetyltrimethylammonium bromide (CtAB), n-hexanol, n-heptane and water were prepared and characterized. the optimized reaction conditions were determined, and monodispersed droplets of the reverse micelles were used as microreactors to synthesize CdS nanoparticles. By using transmission electron microscopy (tEM), UV-Vis spectroscopy and fluorescence spectroscopy, the influences of the reverse micelle components on the size, size distribution, morphology, stability and optical properties of CdS nanoparticles were investigated. CdS nanoparticles with narrow size distribution were obtained and the size range is 6-8 nm when W=24 (W=[water]/[CtAB]), F=5.27 (p=[n-hexanol]/ [CtAB]), [CtAB]=0.2 mol/L, [Cd2+] and [S2-] are 8.45×10-4 mol/L.

关键词： reverse micelles CdS nanoparticles optical properties.