检索结果-南通市图书馆

Grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling

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32期91卷 251-261页

作者： Z.y.Zhao R.G.Guan y.f.shen P.K.Bai School of Materials Science and Engineering North University of ChinaTaiyuan 030051China bEngineering Research Center of Continuous Extrusion Ministry of EducationDalian Jiaotong UniversityDalian 116028China Key Laboratory for Anisotropy and Texture of Materials Northeastern UniversityShenyang 110004China

We elucidate the effect of lanthanum(La) on the grain refinement of Mg-3 Sn-1 Mn alloy during accumulative hot rolling. The lath-shaped Mg_(2) Sn phase in the Mg-3 Sn-1 Mn alloy is firstly broken and spheroidized,and then the size increases and coarsens with the increase of rolling reduction, most of Mg_(2) Sn move from grain boundary to grain and are homogeneously distributed within the matrix. However, the plate-shaped Mg Sn La compound in Mg-3 Sn-1 Mn-1 La gradually becomes fine, spheroidized, and homogeneously distributed. The grain sizes of Mg-3 Sn-1 Mn and Mg-3 Sn-1 Mn-1 La alloys become fine through dynamic recrystallization(DRX), though the grain refinement of Mg-3 Sn-1 Mn-1 La alloy is better compared to the Mg-3 Sn-1 Mn alloy. A large number of uniformly distributed spherical Mg Sn La compounds pin the dislocations, thus increasing the dislocation density. Hence, the driving force for DRX increases and promotes the formation of deformation bands and more twins, providing the sites for DRX nucleation and growth.

关键词： Mg alloy Grain refinement Dynamic recrystallization Accumulative hot rolling

High strength-superplasticity combination of ultrafine-grained ferritic steel:The significant role of nanoscale carbides

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24期83卷 131-144页

作者： J.W.Liang y.f.shen R.D.K.Misra P.K.Liaw Key Laboratory for Anisotropy and Texture of Materials(MOE) School of Materials Science and EngineeringNortheastern UniversityShenyang110004China The State Key Lab of Rolling&Automation Northeastern UniversityShenyang110819China Laboratory for Excellence in Advanced Steel Research University of Texas at El PasoTX79968USA Department of Materials Science and Engineering University of TennesseeKnoxvilleTN37996USA

There is currently a gap in our understanding of mechanisms that contribute to high strength and high plasticity in high strength UfG ferritic steel with nano-size fe3 C carbides in situations that involve combination of various strain rates and high *** this regard,we describe the mechanistic basis of obtaining high strength-high plasticity combination in an ultrafine-grained(UfG)(~500±30 nm)ferritic steel with nano-size carbides,which sustained large plastic deformation,exceeding 100%elongation at a temperature significantly below 0.5 of the absolute melting point(Tm).To address the missing gap in our knowledge,we conducted a series of experiments involving combination of strain rate and temperature effects in conjunction with electron microscopy and atom probe tomography(APT).Strain rate studies were carried out at strain rates in the range of 0.0017-0.17 s^(-1)and at different temperatures from 25℃to 600℃.Dynamic recrystallization occurred at 600℃,resulting in a significant decrease in yield and tensile ***,the UfG ferritic steels had an advantage in tensile strength(UTS)and elongation-to-failure(εf)at 600℃,especially at strain rate of 0.0017 s^(-1),with high UTSof 510 MPa and excellent low temperature(y(εf=110%).These mechanical properties are significantly superior compared to similar type of steels at identical temperature.A mechanistic understanding of mechanical behavior of UfG ferritic steels is presented by combining the effect of strain rate,temperature,and nano-size carbides.

关键词： UfG ferritic steel Strain rate Temperature Nano-size precipitate Low temperature superplasticity

Rational Solutions of first Order Algebraic Ordinary Differential Equations

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第2期37卷 567-580页

作者： fENG Shuang shen Liyong School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjing 211816China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Let f(t,y,y')=∑ _(i=0)^(n )a_(i)(t,y)y'^(i)=0 be an irreducible first order ordinary differential equation with polynomial *** in 1998 proved that there exists a constant C such that every rational solution of f(t,y,y')=0 is of degree not greater than *** show that this degree bound C depends not only on the degrees of f in t,y,y' but also on the coefficients of f viewed as the polynomial in t,y,y'.In this paper,the authors show that if f satisfies deg(f,y)f,y')or n max i=0{deg(a_(i),y)−2(n−i)}>0,then the degree bound C only depends on the degrees of f in t,y,y',and furthermore we present an explicit expression for C in terms of the degrees of f in t,y,y'.

关键词： Degree bound first order AODE height rational solution

同方期刊数据库

Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong fu Junjun shen Uceu f.H.R.Suhuddin Björn Wiese yuanding Huang Min Wang Jorge f.dos Santos Jean Pierre Bergmann Benjamin Klusemann Solid State Materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany functional Magnesium Materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied Materials and Manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain Mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CfP)”,was *** CfP,defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were *** to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process *** compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear *** the base material to the rod,the material experienced three stages,*** by the tool,upward flow with additional tilt,followed by upward *** microstructural evolution was revealed by“stop-action”*** microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRX)as well as particle stimulated nucleation,while that within the rod is related to DRX combined with grain growth.

关键词： Constrained friction processing Magnesium alloys Microstructure Mechanical properties Grain refinement Plastic deformation

Recursive filtering for Stochastic Systems With filter-and-forward Successive Relays

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1202-1212页

作者： Hailong Tan Bo shen Qi Li Hongjian Liu School of Mathematics-Physics and finance Anhui Polytechnic UniversityWuhu 241000China Anhui future Technology Research Institute Anhui Polytechnic UniversityWuhu 241000China College of Information Science and Technology Donghua UniversityShanghai 201620China Engineering Research Center of Digitalized Textile and fashion Technology Ministry of EducationShanghai 201620China School of Information Science and Engineering Hangzhou Normal UniversityHangzhou 311121China

In this paper,the recursive filtering problem is considered for stochastic systems over filter-and-forward successive relay(ffSR)*** ffSR is located between the sensor and the remote filter to forward the *** the successive relay,two cooperative relay nodes are adopted to forward the signals alternatively,thereby existing switching characteristics and inter-relay interferences(IRI).Since the filter-and-forward scheme is employed,the signal received by the relay is retransmitted after it passes through a linear *** objective of the paper is to concurrently design optimal recursive filters for ffSR and stochastic systems against switching characteristics and IRI of ***,a uniform measurement model is proposed by analyzing the transmission mechanism of ***,novel filter structures with switching parameters are constructed for both ffSR and stochastic *** the help of the inductive method,filtering error covariances are presented in the form of coupled difference ***,the desired filter gain matrices are further obtained by minimizing the trace of filtering error ***,the stability performance of the filtering algorithm is analyzed where the uniform bound is guaranteed on the filtering error ***,the effectiveness of the proposed filtering method over ffSR is verified by a three-order resistance-inductance-capacitance circuit system.

关键词： filtering successive stochastic

A Coordinate-free Approach to the Design of Generalized Griffis-Duffy Platforms

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第3期37卷 95-103页

作者： Chengwei shen Xu Pei Lubin Hang Jingjun yu College of Optical Mechanical and Electrical EngineeringZhejiang A&F UniversityHangzhou 311300China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China

Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes *** remaining permanently in a singularity are beneficial for linearto-rotary motion ***-Duffy(GD)platform is a mobile structure admitting a Bricard *** this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed *** generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same *** to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD ***,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.

关键词： Generalized Griffis-Duffy platforms Self-motion Inversion Coordinate-free determination Manipulator design

An mmWave Dual-Band Integrated Substrate Gap Waveguide Single Cavity filter with frequency Selectivity

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

China Communications 2024年第1期21卷 188-199页

作者： Qiuhua Lin Dongya shen Lihui Wang Zhiyong Luo School of Electronics and Communication Engineering Sun Yat-sen UniversityShenzhen 518107China School of Information Science and Engineering Yunnan UniversityKunming 650091China Pengcheng Laboratory Shenzhen 518107China shenzhen Key Laboratory of Navigation and Communication Integration Shenzhen 518107China

A novel dual-band ISGW cavity filter with enhanced frequency selectivity is proposed in this paper by utilizing a multi-mode coupling *** cavity is designed to control the number of modes,and then the ports are determined by analyzing the coupling relationship between these selected *** synthesizing the coupling matrix of the filter,a nonresonating node(NRN)structure is introduced to flexibly tune the frequency of modes,which gets a dualband and quad-band filtering response from a tri-band filter no the ***,a frequency selective surface(fSS)has been newly designed as the upper surface of the cavity,which significantly improves the bad out-of-band suppression and frequency selectivity that often exists in most traditional cavity filter designs and *** results show that its two center frequencies are f01=27.50 GHz and f02=32.92GHz,*** with the dual-band filter that there is no the fSS metasurface,the out-of-band suppression level is improved from measured 5 dB to18 dB,and its finite transmission zero(fTZ)numbers is increased from measured 1 to 4 between the two designed *** with the tri-band and quadband filter,its passband bandwidth is expanded from measured 1.17%,1.14%,and 1.13% or 1.31%,1.50%,0.56%,and 0.57% to 1.71% and 1.87%.In addition,the filter has compact,small,and lightweight characteristics.

关键词： coupling topology frequency selectivity non-resonating node(NRN) out-of-band suppression single ISGW cavity filter

Corrosion behavior and protection mechanism of carbon steel coated with ethylene chlorotrifluoroethylene(ECTfE)

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 502-515页

作者： Peihu shen Jun WEN Biqin DONG Hedong LI Minjia WANG School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou310018China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen518061China Zhejiang Research Institute of Chemical Industry Co. Ltd.Hangzhou310023China

Ethylene chlorotrifluoroethylene(ECTfE)coating was applied to the surface of carbon steel through electrostatic spraying and low-temperature heat *** morphology and structure of the coating were analyzed using various characterization *** electrochemical data of the coated steel soaked in 3.5%(mass fraction)NaCl solution for 90 d at different periods were also *** findings indicate that the outer surface of the coating remains structurally stable before and after soaking.f can diffuse into the steel substrate,facilitating the bonding between the coating and the steel substrate,but the free f also induces a weakening effect on the crystalline *** to the thickness of the coating edge and the susceptibility to infiltration of the corrosive medium,under-film micro-zone corrosion occurs at a slow *** soaking for 90 d,the impedance modulus measures approximately 10^(4)Ω·cm^(2),and the open circuit potential(OCP)is−0.61 *** self-corrosion current density is 1.13×10^(−6)A/cm^(2),resulting in a calculated coating protection rate of 99.29%.In summary,despite edge corrosion occurring,the ECTfE coating provides excellent corrosion protection.

关键词： Coating fluorine resin Edge corrosion Corrosive behavior Electrochemical performance

Pd-Catalyzed Highly Regioselective Hydroesterification of Terminal Alkyl Olefins with formates

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 Journal of Chemistry 2024年第12期42卷 1381-1386页

作者： Junhua Li Tianci shen yan yang yian Shi Jiangsu Key Laboratory of Advanced Catalytic Materials&Technology Schoolof Petrochemical EngineeringInstitute of Natural and Synthetic Organic ChemistryChangzhou UniversityChangzhouJiangsu 213164China

Comprehensive Summary A Pd-catalyzed regioselective hydroesterification of alkyl terminal olefins with aryl formates is described.A wide variety of linear carboxylic esters bearing various functional groups can be obtained in good yields with high regioselectivities under mild reaction conditions by using 1,2-DTBPMB or(p-f-Ph)3P as *** reaction process is operationally simple and requires no handling of toxic CO or strong *** resulting aryl esters can be readily converted to other carboxylic acid derivatives.

关键词： Alkenes Regioselectivity Carbonylation Hydroesterification formates