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Coexistence and fluctuations phenomena with Davidson-like potentials in quadrupoleoctupole deformed nuclei

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Communications in Theoretical Physics 2021年第3期73卷 105-118页

作者： M M hammad w h Mansour E M El-Maghraby h A Motaweh Ayman A Aly Faculty of Science Mathematics DepartmentDamanhour UniversityEgypt Faculty of Science Physics DepartmentDamanhour UniversityEgypt

The energy spectra of three types of two-dimensional potentials(we will call them‘Davidson-like potentials’(DLPs)),characterized by four minima separated by barriers,are *** predictions for spectra and wave functions are obtained by using the nine-point finite-difference *** these potentials,with the existence of a single configuration,a transition of spectra,as a function of barrier height,is covered from tunneling splitting modes to fluctuations phenomena,with equal peaks wave functions,crossing to the spectra of purely anharmonic oscillator potentials(AOPs).A different type of phase transition occurs when two(or more)configurations *** the change of the parameters,a transition of spectra is covered from coexistence phenomena of two distinct quantum tunneling modes to fluctuations phenomena,with unequal peaks wave functions,crossing to the spectra of purely *** DLPs,a particular application of the coherent quadropole-octupole model to describe energy bands with alternating parity of the nuclei^(100)Mo,^(146,148)Nd,^(148,150)Sm,^(220)Ra,^(220,222)Rn,and^(220,222)Th is *** global parametrization of the model for the selected nuclei is achieved.

关键词： quantum phase transitions fluctuations phenomena coherent quadrupole-octupole motion model coexistence phenomena

Nanophase Decomposition of a Zn-Al Based Alloy Zn_(68)Al_(10)Cu_(22)

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Journal of Materials Science & Technology 2004年第6期20卷 687-690页

作者： Y.h.Zhu w.B.Lee S.To Advanced Materials Research Center Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong ChinaAdvanced Materials Research Center Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong ChinaAdvanced Materials Research Center Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong China

The nanostructural evolution and phase transformation of the films of a Zn-Al based alloy (Zn68Al10Cu22 in wt pct) have been studied by using X-ray diffraction and scanning electron microscopy. Nanostructural thin films of the Zn-AI based alloy were produced by using an electron beam deposition technique. It was found that a nanocrystalline phase η'n had a strong preferred crystal orientation at (0002) crystal planes in the as-deposited films. During ageing at 220℃, the decomposition of nanophase η'n started with clustering to form Z-zones, and transitionai phase, which was accompanied by an eutectoid decomposition of the η'n phase: η'n β'eut T'. Decomposition, such as clustering and the formation of the Z-zones, and the transitionai phase etc. were observed in the nanophase β'eut. The formation and the decomposition of the transitionai phase of micrometers in size were involved in the decomposition of the main nanophase η'n. The mechanism of the Z-zones formation and the stability of nanophases were discussed.

关键词： Ageing Nanostructure Nanophase stability Zn-Al based alloy film

Study of Thermal and hydraulic Performances of Circular and Square Ribbed Rough Microchannels Using LBM

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Journal of Thermal Science 2015年第6期24卷 549-556页

作者： M.A.Taher h.D.Kim Y.w Lee Department of Mechanical and Automotive Engineering Pukyong National University Department of Mechanical Engineering Andong National University

The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this *** micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is *** roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel *** friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness *** thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of *** results have been compared with previous published works and it is found to be in very good agreement.

关键词： Lattice-Boltzmann Friction factor Knudsen number Surface Roughness

NUMERICAL MODELING OF DONGZhUANG RESERVOIR ON JING RIVER

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Journal of hydrodynamics 2001年第2期13卷 68-71页

作者： Yang, M. Zhang, h.Y. Zhang, J.h. Zhang, h.w. Dept. 5 Beijing Univ. of Aero. and Astron. Beijing 100084 China

The Dongzhuang Reservoir will be constructed on the Jing River, which is laden with the highest sediment concentration in the world. The sediment problem is a key challenge for the reservoir design and management. This paper presents essential data, details of sediment scour and siltation calculated by the numerical modeling based on new fundamental equations. Calculated results prove that the reservoir could preserve long-term storage capacity with the operation was offered by the design department.

关键词： Flow of fluids Mathematical models Sediments Storage (materials)

Trajectory Generation for Autonomous Soaring UAS

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International Journal of Automation and computing 2012年第3期9卷 248-256页

作者： J. h. A. Clarke w. h. Chen Department of Aeronautical and Automotive Engineering Loughborough University

As unmanned aerial vehicles are expected to do more and more advanced tasks, improved range and persistence is required. This paper presents a method of using shallow layer cumulus convection to extend the range and duration of small unmanned aerial vehicles. A simulation model of an X-models XCalubur electric motor-glider is used in combination with a refined 4D parametric thermal model to simulate soaring flight. The parametric thermal model builds on previous successful models with refinements to more accurately describe the weather in northern Europe. The implementation of the variation of the MacCready setting is discussed. Methods for generating efficient trajectories are evaluated and recommendations are made regarding implementation.

关键词： Unmanned aerial vehicles (UAV) unmanned aerial systems (UAS) soaring trajectory thermal optimal heuristic

SIMULATION OF ThE MAGNETIZATION REVERSAL PROCESS OF RECTANGLE-ShAPED NiFe FILM ELEMENTS UNDER AN ORThOGONAL MAGNETIC FIELD

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 642-646页

作者： w.L. Zhang R.J. Tang w.X. Zhang B. Peng h. C. Jiang h.w. Zhang School of Microelectronics and Solid-state Electronics University of Electronic Science and Technology of China Chengdu 610054 China

The magnetization reversal process of nano-size rectangle-shaped NiFe film elements with different aspect ratios have been investigated under the orthogonally applied magnetic fields by micromagnetic simulation. Different magnetization reversal modes can appear depending on whether the bias field is applied or not. when there is no bias field, double “C” state is the initial reversal state. however, when there is a bias field, “S” state is the starting mode. The larger the aspect ratio is, the larger the switching field is. But, when the aspect ratio is larger than 3, the increase of the switching field ceases. These results can provide useful information to the application of the patterned NiFe film with rectangular elements.

关键词： NiFe film element micromagnetics aspect ratio magnetization reversal,switching field

Thickness-dependent mechanical properties of nacre in Cristaria plicata shell:Critical role of interfaces

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Journal of Materials Science & Technology 2020年第9期44卷 1-8页

作者： S.M.Liang h.M.Ji X.w.Li Department of Materials Physics and Chemistry School of Materials Science and EngineeringKey Laboratory for Anisotropy and Texture of MaterialsMinistry of EducationNortheastern UniversityShenyang110819China

The thickness dependence of mechanical properties of nacre in Cristaria plicata shell was studied under three-point bending *** results show that the mechanical behavior of nacre exhibits a strong thickness *** bending strength firstly increases with the increase of specimen thickness and then becomes roughly constant as the thickness reaches a certain value of∼***,the mean value of work per unit volume increases constantly with increasing specimen thickness;meanwhile,the cracking mode changes from penetration into the platelets to deflection along the *** theoretical analyses indicate that the thickness-dependent mechanical properties of nacre are mainly caused by the variation in the number of inter-lamellar *** more the number of inter-lamellar interfaces is,the higher the strength and work of fracture of nacre under bending tests will ***,as the number of inter-lamellar interfaces reaches a certain value(e.g.,in the present specimen with 2.5mm thickness),the strength tends to remain constant,while the work of fracture still ***,the present research findings are expected to provide a valuable guidance for the interfacial design of nacre-like materials with high strength and toughness.

关键词： Cristaria plicata shell Nacre Mechanical property Thickness Interface

A high-strength and high-toughness nacreous structure in a deep-sea Nautilus shell:Critical role of platelet geometry and organic matrix

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Journal of Materials Science & Technology 2021年第29期88卷 189-202页

作者： S.M.Liang h.M.Ji X.w.Li Department of Materials Physics and Chemistry School of Materials Science and EngineeringNortheastern UniversityShenyang110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819China Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang110819China

To explore the differences in mechanical behavior of nacre between shells that live in different water depths,the microstructures,phase composition and related mechanical properties of nacre under indentation,three-point bending and shear tests in deep-sea Nautilus and freshwater Cristaria plicata shells were systematically *** is found that the nacreous structure in Nautilus shell exhibits an outstanding combination of high strength and high toughness compared with that in *** shell,attributing to its larger aspect ratio of platelet and interfacial shear ***,the interfacial resistance is mainly generated from the adhesion of organic matrix and friction caused by nano-asperities on platelet *** to the interfacial resistance model,the stiction force originated from organic matrix adhesion is sensitive to its content,and the friction force produced by nano-asperities presents a positive correlation with their distribution density and ***,the higher content of organic matrix of nacre with denser and larger nano-asperities on platelet surfaces in Nautilus shell contributes to a higher interfacial ***,it is the coupled effects of platelet geometries(*** ratio and nano-asperity)and organic matrix that result in the high-strength and high-toughness nacreous structure in Nautilus shell,which is thus more conductive to inhabit in the deep sea with extremely high *** present research findings are expected to provide beneficial references for the design of strong and tough nacre-inspired materials with appropriate platelet geometry and content of soft phase.

关键词： Deep-sea Nautilus shell Nacre Mechanical property Platelet geometry Organic matrix

Composition and size dependent torsion fracture of metallic glasses

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Journal of Materials Science & Technology 2021年第23期82卷 153-160页

作者： J.Dong J.Shen Y.h.Sun h.B.Ke B.A.Sun w.h.wang h.Y.Bai Institute of Physics Chinese Academy of SciencesBeijing100190PR China College of Materials Science and Opto Electronic Technology University of Chinese Academy of SciencesBeijing100049PR China Songshan Lake Materials Laboratory DongguanGuangdong523808PR China

The fracture of metallic glasses(MGs)of different compositions and sizes down to micrometers under torsion loading were systematically *** to the flat shear fracture along the circumferential plane as commonly supposed under torsion,we find that the torsion fracture of metallic glasses can deviate from flat shear plane,and the fracture angle is closely dependent on the composition and the size of MG *** a conversion method,we show that the torsion fracture of both millimeterand micrometer-sized MGs can be described by the ellipse fracture criterion as originally proposed for the tension *** deviation from the circumferential shear plane under torsion is further shown to intrinsically relate to the fracture toughness of *** tougher MG tends to have a smaller fracture angle with respect to the maximum shear plane,and vice versa,indicating a correlation between the fracture toughness and pressure/normal stress sensitivity in *** results provide new insights on the fracture mechanism and are helpful to design and control the deformation and fracture behavior of MGs under torsion loading.

关键词： Metallic glasses Torsion fracture Pressure sensitivity Fracture toughness