检索结果-南通市图书馆

Acta Metallurgica sinica(English letters) 2021年第2期34卷 196-204页

作者： s.bi b.l.Xiao Z.H.Ji b.s.liu Z.Y.liu Z.Y.Ma shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China school of Material science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China AVIC Manufacturing Technology Institute Beijing 100024China

High-energy ball milling(HEbM)combined with powder metallurgy route was used to fabricate carbon nanotube(CNT)reinforced 7055 Al *** powder morphology evolution processes(HEbM-1 and HEbM-2)were designed to investigate the dispersion and damage of CNTs during HEbM ***-1 evolution process involved powder fl attening,cold-welding and fracture,while HEbM-2 evolution process consisted of powder fl attening and *** HEbM-1,the repetitive fracture and cold-welding process was effective for dispersing ***,the powder fl attening process in HEbM-2 was unsuccessful in dispersing CNTs due to two reasons:(1)the thickness of fl aky Al powders exceeded the critical value,and(2)the clustered CNTs embedded in fl aky Al powders could not be *** of the broadening of D band and the appearance of a new defect-related D’band,product of I D/I G and full width half maximum of D band,rather than I D/I G,was used to evaluate the actual damage of *** indicates that the damage of CNTs was severe in powder fl attening and fracture stages,while the damage of CNTs was small in powder cold-welding stage.

关键词： Metal matrix composites Carbon nanotubes Powder evolution Dispersion and damage Powder metallurgy

Microstructures and Mechanical Properties of Vacuum brazed Ti3Al/TiAl Joints Using Two Ti-based Filler Metals

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2016年第4期32卷 372-380页

作者： H.s.Ren H.P.Xiong b.Chen s.J.Pang b.Q.Chen l.Ye Department of Material science and Engineering Beihang University Beijing 100191 China Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials Beijing 100095 China

Vacuum brazing of Ti3Al-based alloy to TiAI was firstly carried out by Ti-15Cu-15Ni （wt%） filler metal. A continuous Ti3Al band, Ti2Ni and Ti2Cu/Cu3Ti phases formed and the joint showed a shear strength of 53.8-112.4 MPa at room temperature. For the improvement of the joint strength, a new Ti--Zr--Cu--Ni--Fe filler alloy was designed, and its wettability on Ti3AI and TiA1 substrate was studied with the sessile drop method. After holding for 20 rain at 1010 ℃ the Ti--Zr--Cu--Ni--Fe filler showed a low contact angle of 20° and 21° on Ti3Al and TiAI substrate, respectively. The joint brazed with this novel filler mainly con- sisted of Ti-rich area, Ti3Al reaction layer and residual filler metal. With the increase of the brazing temperature, the amount of residual filler metal decreased and the TisAl reaction layer thickened. The Ti3Al/TiA1 joint brazed with Ti--Zr--Cu--Ni--Fe filler exhibited a lower hardness than that brazed with Ti--Cu--Ni filler. The corresponding joints brazed at 950 ℃ for 5 min presented the shear strength of 257.6± 33.6 MPa at room temperature and 304.8 ± 9.9 MPa at 600 ℃.

关键词： brazingTitanium aluminidesMicrostructureshear strength

Analytical solution of the blast Wave Problem in a Non-Ideal Gas

在线全文

学校读者我要写书评

暂无评论

Chinese Physics letters 2011年第11期28卷 152-154页

作者： l.P.singh s.D.Ram D.b.singh Department of Applied Mathematics Institute of TechnologyBanaras Hindu UniversityVaranasi-221005India

An analytical approach is used to construct the exact solution of the blast wave problem with generalized geometries in a non-ideal *** is assumed that the density ahead of the shock front varies according to a power of distance from the source of the blast ***,an analytical expression for the total energy in a non-ideal medium is derived.

关键词： wave analytical assumed

Twinnability Predication for fcc Metals

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 Materials science & Technology 2011年第2期27卷 97-100页

作者： b.Q.li M.l.sui s.X.Mao shenyang National laboratory for Materials science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Institute of Microstructure and Properties of Advanced Materials Beijing University of TechnologyBeijing 100124China Department of Mechanical Engineering and Materials science University of PittsburghPittsburghPennsylvania 15261USA

Inherent twinnability of face-centered-cubic（fcc） metals was analyzed based on the direct competition between twinning partial dislocation nucleation and trailing partial dislocation nucleation,with which the twinnability of fcc metals can be simply expressed as function of the stacking-fault energy,the unstable stacking-fault energy,and the unstable twinningfault energy of fcc *** predicted twinnability ranking matched well with former experimental results and provided a physical insight to understand twinnability from crystallographic orientation and fault energy parameters.

关键词： Deformation twinning fcc metals Twinnability

Nonlinear vibration of an elastically restrained tapered beam

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1925-1930页

作者： KARIMPOUR s. GANJI s.s. bARARI A. IbsEN l.b. DOMAIRRY G. Department of Civil and Mechanical Engineering Babol University of TechnologyP.O.Box 484BabolIran Young Researchers Club Science and Research BranchIslamic Azad UniversityTehranIran Department of Civil Engineering Aalborg UniversitySohng rdsholmsvej 57DK-9000 AalborgAalborgDenmark

This paper presents the analytical simulation of an elastically restrained tapered cantilever beam using the energy balance method(EbM) and the iteration perturbation method(IPM).To assess the accuracy of solutions,we compare the results with the harmonic balance method(HbM).The obtained results from EbM and IPM are in excellent agreement with HbM *** results show that both methods can be easily extended to other nonlinear oscillations and it can be predicted that both methods can be found widely applicable in engineering and physics.

关键词： energy balance method (EbM) iteration perturbation method (IPM) nonlinear oscillation

brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs Víctor Cilleros-Mañé laia Just-borràs Marta balanyà-segura Aleksandra Polishchuk laura Nadal Marta Tomàs Carolina silvera-simón Manel M.santafé Maria A.lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase b receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated Trkb/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through l-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorb

Mechanical properties of gas hydrate-bearing sediments during hydrate dissociation

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica sinica 2018年第2期34卷 266-274页

作者： X.H.Zhang D.s.luo X.b.lu l.l.liu C.l.liu Institute of Mechanics Chinese Academy of SciencesBeijing 100190China College of Engineering University of Chinese Academy of SciencesBeijing 100049China Key laboratory of Gas Hydrate Ministry of Land and ResourcesQingdao 266071China Qingdao Institute of Marine Geology Qingdao 266071China

The changes in the mechanical properties of gas hydrate-bearing sediments(GHbs) induced by gas hydrate(GH) dissociation are essential to the evaluation of GH exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GHbs at a given GH saturation under the non-dissociated condition. In this paper, GHbs was formed by the gas saturated method, GH was dissociated by depressurization until the GH saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with GH dissociation, and the modulus decreases by 50% –75%. simplified relationships for the modulus, cohesion, and internal friction angle with GH dissociated saturation were presented.

关键词： Gas hydrate-bearing sediments Dissociation Mechanical properties shear strength Triaxial test

Petrogenesis of carbonatitic lamproitic dykes from sidhi gneissic complex,Central India

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第2期9卷 531-547页

作者： M.satyanarayanan D.V.subba rao M.l.Renjith s.P.singh E.V.s.s.K.babu M.M.Korakoppa CsIR-National Geophysical Research Institute Hyderabad 500007India Geological survey of India Hyderabad 500068India Department of Geology Bundelkhand UniversityJhansi 284128India NCEGR Geological Survey of IndiaBengaluru 560070India

Petrographic, mineral chemical and whole-rock geochemical characteristics of two newly discovered lamproitic dykes(Dyke 1 and Dyke 2) from the sidhi Gneissic Complex(sGC), Central India are presented here. both these dykes have almost similar sequence of mineral-textural patterns indicative of:(1) an early cumulate forming event in a deeper magma chamber where megacrystic/large size phenocrysts of phlogopites have crystallized along with subordinate amount of olivine and clinopyroxene;(2) crystallization at shallow crustal levels promoted fine-grained phlogopite, K-feldspar, calcite and Fe-Ti oxides in the groundmass;(3) dyke emplacement related quench texture(plumose K-feldspar, acicular phlogopites) and finally(4) post emplacement autometasomatism by hydrothermal fluids which percolated as micro-veins and altered the mafic phases. Phlogopite phenocrysts often display resorption textures together with growth zoning indicating that during their crystallization equilibrium at the crystal-melt interface fluctuated multiple times probably due to incremental addition or chaotic dynamic self mixing of the lamproitic magma. Carbonate aggregates as late stage melt segregation are common in both these dykes, however their micro-xenolithic forms suggest that assimilation with a plutonic carbonatite body also played a key role in enhancing the carbonatitic nature of these dykes. Geochemically both dykes are ultrapotassic(K_2 O/Na_2 O: 3.0-9.4) with low CaO, Al_2 O_3 and Na_2 O content and high siO_2(53.3-55.6 wt.%)and K_2 O/Al_2 O_3 ratio(0.51-0.89) characterizing them as high-silica lamproites. Inspite of these similarities, many other features indicate that both these dykes have evolved independently from two distinct magmas. In dyke 1, phlogopite composition has evolved towards the minette trend(Al-enrichment) from a differentiated parental magma having low MgO, Ni and Cr content; whereas in dyke 2, phlogopite composition shows an evolutionary affinity towards the lamproit

关键词： lamproite Phlogopite Carbonate aggregates Metasomatized mantle sidhi Gneissic Complex Central India

High mechanical strengths and ductility of stainless steel 304l fabricated using selective laser melting

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2019年第2期35卷 388-394页

作者： Q.b.Nguyen Z.Zhu F.l.Ng b.W.Chua s.M.l.Nai J.Wei singapore Institute of Manufacturing Technology Institute of Research and Development Duy Tan University

Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 l fully dense samples were successfully printed using the 3 D systems – ProX 300 printing machine. The ductility and tensile yield strength were almost two and three times higher compared to those of AsTM cast's alloy. Honey comb like nano-cellular structure with different orientation was observed in the fine grains(~4μm) due to fast cooling rate. In addition, the formation of martensite phase in random grains is also a contributor to the strengths. Furthermore, negative residual stresses in the build and horizontal directions were detected and assisted further increase in the tensile strength. Fractography revealed the ductile feature of plastic deformation and the crack openings at unmelted particles or pores.

关键词： Additive manufacturing stainless steel Powder selective laser melting

Replica symmetry breaking in 1D Rayleigh scattering system:theory and validations

在线全文

学校读者我要写书评

暂无评论

light(science & Applications) 2024年第9期13卷 1757-1765页

作者： Yifei Qi longqun Ni Zhenyu Ye Jiaojiao Zhang Xingyu bao Pan Wang Yunjiang rao Ernesto P.Raposo Anderson s.l.Gomes Zinan Wang Key lab of Optical Fiber sensing&Communications University of Electronic Science and Technology of China(UESTC)ChengduChina laboratório de Física Teórica e Computacional Departamento de FísicaUniversidade Federal de Pernambuco50670-901 RecifePernambucoBrazil Departamento de Física Universidade Federal de PernambucoRecifePernambucoBrazil

spin glass theory,as a paradigm for describing disordered magnetic systems,constitutes a prominent subject of study within statistical *** symmetry breaking(Rsb),as one of the pivotal concepts for the understanding of spin glass theory,means that under identical conditions,disordered systems can yield distinct states with nontrivial *** fiber laser(RFl)based on Rayleigh scattering(Rs)is a complex disordered system,owing to the disorder and stochasticity of *** this work,for the first time,a precise theoretical model is elaborated for studying the photonic phase transition via the platform of Rs-based RFl,in which we clearly reveal that,apart from the pump power,the photon phase variation in RFl is also an analogy to the temperature term in spin-glass phase transition,leading to a novel insight into the intrinsic mechanisms of photonic phase *** addition,based on this model and real-time high-fidelity detection spectral evolution,we theoretically predict and experimentally observe the mode-asymmetric characteristics of photonic phase transition in Rs-based *** finding contributes to a deeper understanding of the photonic Rsb regime and the dynamics of Rs-based RFl.

关键词： transition. symmetry breaking