检索结果-南通市图书馆

Journal of Iron and Steel Research International 2022年第5期29卷 819-835页

作者： J.l.Guo t.J.Chen State Key laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050GansuChina

the effects of H_(2)SO_(4)concentration and current in electrochemical corrosion on surface layer softening or plasticizing of Q235 steel bar and their effects on subsequent electrochemical cold drawing(ECD)were *** results indicate that the electrochemical corrosion can soften or plasticize the surface layer of Q235 steel bar and then make the subsequent ECD be conducted more *** softening degree and thickness of the surface layer are continuously enhanced with increasing corrosion rate,i.e.,increasing H_(2)SO_(4)concentration or current,due to the generation of more vacancy clusters in deeper regions of surface *** vacancy clusters then relax dislocations through being absorbed during ECD,and the formation and movement of additional dislocation flux are thereby enhanced,resulting in the further obvious decrease in the drawing *** is also due to the enhanced formation and movement of additional dislocation flux that the dislocation density and thus the hardness of the surface layer are decreased,as well as that the texture structure is *** behaviors are enhanced as the corrosion rate increases.

关键词： Electrochemical corrosion Electrochemical cold drawing Surface layer softening Vacancy Additional dislocation flux

Nonlinear-Optical Analogies in Nuclear-like Soliton Reactions:Selection Rules,Nonlinear tunneling and Sub-Barrier Fusion–Fission

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 Physics letters 2024年第8期41卷 1-7页

作者： t.l.Belyaeva V.N.Serkin Universidad Autonoma del Estado de Mexico Av.Instituto Literario 100C.P.50000TolucaMexico Benemerita Universidad Autonoma de Puebla Av.4 Sur 104C.P.72001PueblaMexico

the main goal of our study is to reveal unexpected but intriguing analogies arising between optical solitons and nuclear physics,which still remain hidden from *** consider the main cornerstones of the concept of nonlinear optics of nuclear reactions and the well-dressed repulsive-core *** the base of this model,we reveal the most intriguing properties of the nonlinear tunneling of nucleus-like solitons and the soliton selfinduced sub-barrier transparency *** describe novel interesting and stimulating analogies between the interaction of nucleus-like solitons on the repulsive barrier and nuclear sub-barrier *** main finding of this study concerns the conservation of total number of nucleons(or the baryon number)in nuclear-like soliton *** show that inelastic interactions among well-dressed repulsive-core solitons arise only when a“cloud”of“dressing”spectral side-bands appears in the frequency spectra of the *** property of nucleus-like solitons is directly related to the nuclear density distribution described by the dimensionless small shape-squareness *** the Fourier spectra of nucleus-like solitons are similar to the nuclear form *** show that the nuclear-like reactions between well-dressed solitons are realized by“exchange”between“particle-like”side bands in their spectra.

关键词： solitons soliton Nonlinear

Influences of residual stress and micro-deformation on microstructures and mechanical properties for ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy produced by laser powder bed fusion

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2021年第16期75卷 174-183页

作者： C.C.Zhang H.l.Wei t.t.liu l.Y.Jiang t.Yang W.H.liao National Joint Engineering Research Center of NC Forming technology and Equipment School of Mechanical EngineeringNanjing University of Science and TechnologyNanjing 210094China

laser powder bed fusion(lPBF)yields unique advantages during the fabrication of titanium *** the present work,ti-6.5 Al-3.5 Mo-1.5 Zr-0.3 Si alloy specimens with excellent mechanical performances were fabricated by *** as-built specimens displayed relatively high strength and ductility under modest volume energy densities(VEDs),whereas they manifested high strength with low ductility under high *** investigate the key reason of this phenomenon,the specimens were designed with two VEDs ranges of 60 J/mm^(3) and 85 J/mm^(3).Special attention was paid to the influences of residual stress and micro-deformation on microstructures and mechanical properties for the first *** results indicated that the residual stresses and relative density of the 60 J/mm^(3) range specimens were higher than that of the 85 J/mm3 range *** multiplication and dislocation movement promoted by the residual stress were hindered by the initialα’phase grain boundary(prior-α’GB),leading to the formation ofα’metastable *** mean tensile strength and elongation of the 60 J/mm^(3) range specimens were 1248.1 MPa and 12.3%,respectively,whereas the corresponding values for the 85 J/mm^(3) range specimens were 1405.3 MPa,5.0%,*** deformation,the strength and ductility of the specimens were first improved by lamellar structures generated from prior-α’phases,and then effectively enhanced by the interaction between the{10–12}twins and ***,pores significantly reduced the ductility;hence,high VED specimens with large twins and numerous large pores increased the strength and reduce the ductility.

关键词： laser powder bed fusion ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy Residual stress twin Mechanical properties

long-time Shoreline Monitoring of the Vellar Estuarine Complex,Southeast Coast of India:Using Multispectral Satellite Data

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2012年第6期23卷 900-907页

作者： l Senthilnathan E P Nobi t thangaradjou l Kannan Centre of Advanced Study in Marine Biology Faculty of Marine SciencesAnnamalai UniversityParangipettai-608502TamilnaduIndia

the present study was carried out to track the path of Vellar estuary over a period of 38 years （1970-2008） and also to detect the impact of tsunami on estuarine complex of the Vellar estuary. Visual interpretation techniques were employed by using muitispectral data of landsat tM （1991） and IRS-P6 lISS III （2004, 2006, and 2008） to delineate shoreline changes in the VeUar estuarine complex. Results clearly revealed the changes that occurred along the estuarine path over the period, and severe erosion was noticed in the seaward side of the MGR thittu and accretion, along the estuarine mouth. It is also visible that there is clear river path shift in the river course. Although the sandbar formation was seen with only little morphologic modification up to 2004, the Indian Ocean tsunami that struck this coast （26 December, 2004） distorted the sandbar of the Vellar estuarine mouth; however, the 2006 satel- lite images confirmed that the sandbar was formed again to its original structure as that of before the tsunami.

关键词： estuary geomorphology IRS-P6 lISS III shoreline tsunami India.

Multiscale and multiphysics explorations of the transient deposition processes and additive characteristics during laser 3D printing

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2021年第18期77卷 196-208页

作者： H.l.Wei F.Q.liu l.Wei t.t.liu W.H.liao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing.210094China State Key laboratory of Solidification Processing Northwestern Poly technical UniversityXi'an710072China

laser directed energy deposition(DED)involves complex physical processes,and the trial and error examinations are time consuming and cost *** research paradigm can be reshaped using advanced phenomenological models via computing the spatiotemporal variations of the build *** this work,multi-layer and multi-track laser DED of ti-6 Al-4 V were systematically explored on multiple scales including the 1D track,the 2D layer and the 3D full build considering the complex transport of energy,mass,and momentum in the moving freeform molten *** results showed that convex,nearflat,and wavy builds were generated using gradually larger hatch *** profiles of individual tracks and layers were extracted through the unique advantages of the *** individual tracks exhibited various patterns and rotated with specific inclinations to form distinct layer *** net increments of the deposit generated upon the printing of a new track during the continuous deposition process showed that the smaller hatch spacing caused higher overlap rate of horizontally adjacent tracks but lower remelting rate of vertically adjacent tracks in neighboring *** 3D numerical model was validated with corresponding experiments for various process *** scientific findings can provide useful insights for further researches of DED.

关键词： Additive manufacturing Multi-layer and multi-track Numerical model Build features Molten pool

Recent Advances in Catalytic Carbonylation Reactions in Alternative Reaction Media

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第4期42卷 406-429页

作者： Csaba Árvai lászló t.Mika Department of Chemical and Environmental Process Engineering Faculty of Chemical Technology and BiotechnologyBudapest University of Technology and EconomicsMűegyetem rkp.3H-1111 BudapestHungary

Since the discovery of the hydroformylation(oxo-synthesis or Roelen reaction)and the Reppe-reaction,the transition metal-catalyzed carbonylation reactions,providing versatile,facile,and even atom-economic methods for the selective incorporation of C=O functionality to various skeletons,have gained tremendous importance in synthetic organic chemistry from laboratories to industrial *** carbonylation of carbon-carbon multiple bonds,aromatic halides,triflates,etc.,in the presence of various nucleophiles has led the way to produce aldehydes,carboxylic acids,esters,amides,etc.,in the fine chemical ***,these protocols usually proceed in conventional,fossil-based,and usually toxic reaction ***,several attempts have been directed to developing efficient carbonylation methods in alternative,less harmful,non-fossil-based and even in renewable reaction *** this review,we overview the recent applications of alternative solvents such as water,biomass-based alcohols,γ-valerolactone(GVl),2-methyltetrahydrofuran(2-MetHF),ionic liquids(Ils),deep eutectic solvents(DES),alkyl levulinates,limonene,α-pinene,and dimethyl carbonate as well as fluorous media to improve efficiency,safety and environmentally benign nature of carbonylation protocols.

关键词： Carbonylation Catalysis Solvents Green chemistry Carbon monoxide transition metals Homogeneous catalysis Palladium

Nonplanar flow-induced vibrations of a cantilevered PIP structure system concurrently subjected to internal and cross flows

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

Acta Mechanica Sinica 2019年第6期35卷 1241-1256页

作者： Z.Y.liu t.l.Jiang l.Wang H.l.Dai Department of Mechanics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key laboratory for Engineering Structural Analysis and Safety Assessment Wuhan 430074China

Pipe-in-pipe(PIP)structures are widely used in offshore oil and gas pipelines to settle thermal insulation issues.A PIP structure system usually consists of two concentric pipes and one softer layer for thermal insulation *** total response of the system is related to the dynamics of both pipes and the interactions between these two concentric *** the current work,a theoretical model for flow-induced vibrations of a PIP structure system is proposed and analyzed in the presence of an internal axial flow and an external cross *** interactions between the two pipes are modeled by a linear distributed damper,a linear distributed spring and a nonlinear distributed spring along the pipe *** unsteady hydrodynamic forces due to cross flow are modeled by two distributed van der Pol wake *** nonlinear partial differential equations for the two pipes and the wake are further discretized by the aid of Galerkin’s technique,resulting in a set of ordinary differential *** ordinary differential equations are further numeri cally solved by using a fourth-order Runge-Kutta integration *** portraits,bifurcation diagrams,an Argand diagram and oscillation shape diagrams are plotted,showing the existence of a lock-in phenomenon and figure-of-eight *** PIP system subjected to cross flow displays some interesting dynamical behaviors different from that of a single-pipe structure.

关键词： Cantilevered PIP structure theoretical model Flow-induced vibration Cross flow Internal flow

Nonlinear stability of advanced sandwich cylindrical shells comprising porous functionally graded material and carbon nanotube reinforced composite layers under elevated temperature

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

Applied Mathematics and Mechanics(English Edition) 2021年第9期42卷 1327-1348页

作者： H.V.tUNG l.t.N.tRANG Faculty of Civil Engineering Hanoi Architectural UniversityHa Noi 10000Viet Nam Faculty of Civil Engineering University of Transport TechnologyHa Noi 10000Viet Nam

the nonlinear stability of sandwich cylindrical shells comprising porous functionally graded material(FGM) and carbon nanotube reinforced composite(CNtRC)layers subjected to uniform temperature rise is investigated. two sandwich models corresponding to CNtRC and FGM face sheets are proposed. Carbon nanotubes(CNts) in the CNtRC layer are embedded into a matrix according to functionally graded distributions. the effects of porosity in the FGM and the temperature dependence of properties of all constituent materials are considered. the effective properties of the porous FGM and CNtRC are determined by using the modified and extended versions of a linear mixture rule, respectively. the basic equations governing the stability problem of thin sandwich cylindrical shells are established within the framework of the Donnell shell theory including the von K’arm’an-Donnell nonlinearity. these equations are solved by using the multi-term analytical solutions and the Galerkin method for simply supported *** critical buckling temperatures and postbuckling paths are determined through an iteration procedure. the study reveals that the sandwich shell model with a CNtRC core layer and relatively thin porous FGM face sheets can have the best capacity of thermal load carrying. In addition, unlike the cases of mechanical loads, porosities have beneficial effects on the nonlinear stability of sandwich shells under the thermal load. It is suggested that an appropriate combination of advantages of FGM and CNtRC can result in optimal efficiency for advanced sandwich structures.

关键词： carbon nanotube reinforced composite(CNtRC) porous functionally graded material(FGM) thermal instability cylindrical shell advanced sandwich model

Behavioral and olfactory responses of grasshopper hatchlings, Melanoplus sanguinipes, to plant odours and volatile compounds

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2004年第2期49卷 136-141页

作者： KANGle t.l.Hopkins StateKeylaboratoryofIntegratedManagementofPestInsects&Rodents.InstituteofZoology ChineseAcademyofSciencesBeijing100080China DepartmentofEntomology KansasStateUniversityManhattanKS66506USA

Behavior and olfactory responses of grasshopper hatchlings, Melanoplus sanguinipes (F.), to odours from plant foliage and volatile compounds were tested using a glass Y-tube olfactometer and electroantennogram (EAG)techniques respectively. In single choice trials, newly hatched hoppers were much more sensitive to the odour from intact leaves and chopped foliage of ryegrass and wheat than other plants. Chopped sorghum leaves, but not stem-cut sorghum,were also significantly attractive. the orientation responses of grasshopper hatchlings to these plants were highly consistent with those of last instar hoppers and adults. When ryegrass was employed as the control, the odour from stem-cut alfalfa was more attractive. there was no significant difference in hopper orientation responses to the odours from chopped seedlings of sorghum, alfalfa, wheat or ***, significantly more hoppers preferred the chopped ryegrass control to chopped louisanna sage. Measurement of the EAG response of first instar hoppers to these plant odours showed that the odour of louisanna sage elicited the greatest response amplitudes. In olfactory tests using different volatile components, Z-3-hexenol, E-3-hexenol,Z-hex-3-enyl acetate, E-2-hexenal and hexenal gave greater EAG responses than geraniol and 1-octen-3-ol. these results are also consistent with comparable data from adults. Newly hatched grasshoppers had similar EAG response profiles to plant materials and chemicals to those of adults, although the absolute EAG values of young hoppers were much lower than those of adults. therefore, newly hatched hoppers were able to distinguish plants from an air control, and even host plants from non-host plants, and the feeding experience of hoppers probably has little influence on their subsequent ability as adults to identify and locate food plants.

关键词：嗅觉蝗虫挥发性化合物植物保护

BESt APPROXIMAtION FOR WEIERStRASS tRANSFORM CONNECtED WItH SPHERICAl MEAN OPERAtOR

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2012年第2期32卷 455-470页

作者： l.t.Rachdi N.Msehli Département de Math'ematiques Facult'e des Sciences de Tunis2092 El-ManarTunisia Département de Mathématiques et d'informatique Institut National des Sciences Appliquées et de Technologie de Tunis1080 TunisTunisia

Using reproducing kernels for Hilbert spaces, we give best approximation for Weierstrass transform associated with spherical mean operator. Also, estimates of extremal functions are checked.

关键词： Weierstrass transform spherical mean operator best approximation repro-ducing kernel extremal function