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Gap solitons of spin–orbit-coupled Bose–Einstein condensates in PT periodic potential

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Chinese Physics B 2022年第1期31卷 140-145页

作者： S Wang Y h Liu T f Xu hebei Key Laboratory of Microstructural Material Physics School of ScienceYanshan UniversityQinhuangdao 066004China School of Science Yanshan UniversityQinhuangdao 066004China

We numerically investigate the gap solitons in Bose–Einstein condensates(BECs)with spin–orbit coupling(SOC)in the parity–time(PT)-symmetric periodic *** find that the depths and periods of the imaginary lattice have an important influence on the shape and stability of these single-peak gap solitons and double-peak gap solitons in the first band *** dynamics of these gap solitons are checked by the split-time-step Crank–Nicolson *** is proved that the depths of the imaginary part of the PT-symmetric periodic potential gradually increase,and the gap solitons become *** the different periods of imaginary part hardly affect the stability of the gap solitons in the corresponding parameter interval.

关键词： gap solitons spin–orbit coupling PT-symmetric periodic potential

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海面的小入射余角雷达后向散射

雷达与对抗 1992年第4期13卷 7-13,22页

作者： h.f.赫尔姆肯肖梁

利用位于夸贾林靶场的罗依-纳幕尔岛上的L、S和C波段雷达同时对小入射余角(<0.1°)雷达后向散射进行了一系列的测量。利用各种波形,以连续的1.26km的步长,记录了海情为3级和5级、距离从8km到60km时的相干数据。本文详细地介绍了入射余... 详细信息

利用位于夸贾林靶场的罗依-纳幕尔岛上的L、S和C波段雷达同时对小入射余角(<0.1°)雷达后向散射进行了一系列的测量。利用各种波形,以连续的1.26km的步长,记录了海情为3级和5级、距离从8km到60km时的相干数据。本文详细地介绍了入射余角很小、距离大大超过视距时的新的频谱测量结果。这些测量结果证明了来自视距之外的雷达回波的相干性,而且证明了净空对小入射余角海杂波数据的扰动的存在和影响。证明相干性是因为在60km的距离内存在着有意义的多卜勒频谱的缘故。可以看出,逆风谱在整个测量范围内是双峰的。一个分量以风速运动,另一个分量以接近1/4的风速运动。文中分别对每一个分量在逆风方向上的主极化和垂直极化作了分析。每一种极化的速度较慢的分量大致相等,而速度较快的分量相差10dB。速度较快的分量可看作是由同质的、各向同性的物体的折射率波动即净空的扰动引起的后向散射。文中把以高分辨率数据观测到的遮挡情况与一些新近的小入射余角后向散射模型的预测情况进行了比较。

关键词：海用雷达海杂波测量散射

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Bulk Al–Al_3Zr composite prepared by mechanical alloying and hot extrusion for high-temperature applications

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 937-942页

作者： E.Pourkhorshid M.h.Enayati S.Sabooni f.Karimzadeh M.h.Paydar Department of Materials Engineering Isfahan University of Technology Department of Materials Science and Engineering School of Engineering Shiraz University

Bulk Al/Al_3Zr composite was prepared by a combination of mechanical alloying(MA) and hot extrusion processes. Elemental Al and Zr powders were milled for up to 10 h and heat treated at 600℃ for 1 h to form stable Al_3Zr. The prepared Al_3Zr powder was then mixed with the pure Al powder to produce an Al–Al_3Zr composite. The composite powder was finally consolidated by hot extrusion at 550℃. The mechanical properties of consolidated samples were evaluated by hardness and tension tests at room and elevated temperatures. The results show that annealing of the 10-h-milled powder at 600℃ for 1 h led to the formation of a stable Al_3Zr phase. Differential scanning calorimetry(DSC) results confirmed that the formation of Al_3Zr began with the nucleation of a metastable phase, which subsequently transformed to the stable tetragonal Al_3Zr structure. The tension yield strength of the Al-10wt%Al_3Zr composite was determined to be 103 MPa, which is approximately twice that for pure Al(53 MPa). The yield stress of the Al/Al_3Zr composite at 300℃ is just 10% lower than that at room temperature, which demonstrates the strong potential for the prepared composite to be used in high-temperature structural applications.

关键词： aluminum matrix nanocomposites mechanical alloying hot extrusion aluminides powder metallurgy

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旅华岁月海伦·斯诺回忆录 1

旅华岁月海伦·斯诺回忆录

heat Convection Between Two Confocal Elliptic Tubes Placed at Different Orientations

1985年

作者：（美）斯诺（Snow h.f.）华谊译

根据纽约威廉·莫罗公司1984年版译出。书名原文: My china years : a memeir by helan foster Snow。

ISBN: (纸本)7003·111

根据纽约威廉·莫罗公司1984年版译出。书名原文: My china years : a memeir by helan foster Snow。

关键词：斯诺学科:生平事迹

来源：汇雅图书（南通市图书馆... 评论

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Advances in Applied Mathematics and Mechanics 2009年第5期1卷 639-663页

作者： f.M.Mahfouz h.M.Badr Department of Mechanical Engineering University of Engineering&TechnologyTaxilaPakistan Department of Mechanical Engineering King Fahd University of Petroleum&MineralsKFUPM Box#322DhahranSaudi Arabia

In this paper,transient and steady natural convection heat transfer in an elliptical annulus has been *** annulus occupies the space between two horizontal concentric tubes of elliptic *** resulting velocity and thermal fields are predicted at different annulus orientations assuming isothermal *** full governing equations of mass,momentum and energy are solved numerically using the fourier Spectral *** heat convection process between the two tubes depends on Rayleigh number,Prandtl number,angle of inclination of tube axes and the geometry and dimensions of both *** Prandtl number and inner tube axis ratio are fixed at 0.7 and 0.5,*** problem is solved for the two Rayleigh numbers of 104 and 105 considering a ratio between the two major axes up to 3 while the angle of orientation of the minor axes varies from 0 to 90◦.The results for local and average Nusselt numbers are obtained and discussed together with the details of both.f.ow and thermal *** isothermal heating conditions,the study has shown an optimum value for major axes ratio that minimizes the rate of heat transfer between the two *** important aspect of this paper is to prove the successful use of the fourier Spectral Method in solving confined flow and heat convection problems.

关键词： heat convection Elliptic tubes fourier spectral methods Rayleigh number Prandtle number

Do mantle plumes exist？

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Episodes 2006年第3期29卷 162-168页

作者： Ian h. Campbell Geoffrey f. Davies Research School of Earth Sciences The Australian National University Canberra ACT 0200 Australia

The physics of low Reynolds number plumes is well understood, which allows a number of testable predictions to be made about mantle plumes. They are predicted to originate from the core-mantle boundary and consist of a large head followed by a narrower tail. Millions of cubic kilometers of magma can be produced from a plume head. Rifting over a previously-emplaced plume head should produce a narrow zone of thickened oceanic crust along the rift margin. Initial eruption from a plume head should be preceded by -1,000 m of domal uplift. Picrites are expected to dominate the first eruptive products of a new plume and should be concentrated near the centre of the volcanic province. All of these predictions are confirmed by observations, and so provide strong support for the validity of the mantle plume hypothesis.

关键词：地幔热流柱数值模型俯冲作用深部构造

Numerical approach to the modelling of transient interaction of prospective combustor concepts and conventional high pressure turbines

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Propulsion and Power Research 2019年第1期8卷 1-12页

作者： f.Bakhtiari h.-P.Sch.f.er Technische University Darmstadt Institute of Gas Turbines and Aerospace PropulsionDarmstadt 64287HessenGermany

The Institute of Gas Turbines and Aerospace Propulsion at Technische Universitait Damstaxlt conducts research projects in the field of“combustor turbine interaction”(CTI).This paper presents numerical studies on the interaction between novel combustion concepts and conventional“high pressure turbine”(hPT)*** order to obtain higher efficiency and reduce emissions of jet engines,it is necessary to apply innovative and revolutionary *** most promising technical solutions are based on the cycle processes,employing“pressure gain combustion”(PGC)methods PGC methods provide a significant thermal efficiency enhancement and low NO_(x)-emission rates at the same *** investigations presented in this paper give information on the integrability of revolutionary combustion concepts into conventional engine *** paper aims at providing insight into the numerical modelling of the transient behaviour of prospective combustion outflow and its influence on the operation of hPTs,especially on the first *** focus is on the aerodynamic effects and loss mechanisms within the blade *** interaction between the two components plays an important *** study the performance under new conditions,an engine-like hPT geometry is *** study reveals a decrease in turbine efficiency with transient inflow conditions compared to a steady-state inflow *** decrease is primarily due to the interation between transient inflow and the loss mechanisms in the *** presented research was done as part of the project“Technologien fir REVolutionire Arbeits Prozesse”(TREVAP)

关键词： Combustor turbine interaction(CTI) Prospective combustor concepts Pressure gaincombus-tion(PGC) high pressureturbine(hPT) Transient computa-tional fluid dynamics(CfD)

heat transfer attributes of Al_(2)O_(3)-fe_(3)O_(4)/h_(2)O hybrid nanofluid flow over a yawed cylinder

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Propulsion and Power Research 2022年第3期11卷 416-429页

作者： P.M.Patil h.f.Shankar Department of Mathematics KLE Technological UniversityB V Bhoomaraddi CampusVidyanagarHubballi-580031India Department of Mathematics Karnatak UniversityPavate NagarDharawad-580003India

flow over yawed and unyawed blunt bodies often occurs in various engineeringapplications. The fluid flow over a yawed cylinder explains the practical significance of subseaapplications such as transference control, separating the boundary layer above submergedblocks, and suppressing recirculating bubbles. The current study uses viscous dissipation toanalyze the mixed convective hybrid nanofluid flow around a yawed cylinder. Unlike the stan-dard nanofluid model, which only considers one type of nanoparticle, this work considers thehybridization of two types of nanoparticles: alumina (Al_(2)O_(3)) and magnetite (fe_(3)O_(4)). A modelwas developed to investigate the heat transport behaviour of a hybrid nanofluid while account-ing for the solid volume fraction. The flow problem is modelled in terms of highly nonlinearpartial differential equations (NPDEs) subject to the appropriate boundary conditions. Thenappropriate non-similar transformations were used to non-dimensionalize the governing equa-tions. furthermore, the non-dimensional governing equations were solved using the finite dif-ference method (fDM) and the quasilinearisation technique. The effects of water andnanoparticle concentrations on the velocity and the temperature patterns were illustrated graph-ically. The hybrid nanofluid reduces the velocity distribution in the spanwise and chordwise di-rections while increasing the surface drag coefficient. The hybrid nanofluid’s fluid temperatureand energy transport strength was higher than the base fluid and nanofluid. Also, the temper-ature of the fluid rises as the energy transfer strength diminishes due to an increase in the Eckert number, which characterizes viscous dissipation. however, when the yaw angle increases in thechordwise and spanwise directions, so does the fluid’s velocity. The new outcomes werecompared to previously published research and were in good agreement.

关键词： Yawed cylinder Mixed convection hybrid nanofluid Eckert number finite difference method

Virtual representations of antique globes-new ways of touching the untouchable

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International Journal of Digital Earth 2008年第1期1卷 107-118,I0007页

作者： f.hruby A.Riedl h.Tomberger Department of Geography and Regional Research Cartography and GeoinformationUniversity of ViennaUniversita tsstrasse 71010 ViennaAustria

The starting point of this paper is the idea that a comprehensive understanding of the earth and its systems calls for consideration of bygone views of the *** facsimiles of antique globes in the form of digital globes provides a new opportunity to make such bygone world views accessible to a wide scientific ***,up to now,little practical experience in applying digital technology on globes has been *** these attempts by thorough synopsis,this article deduces a comprehensive approach on virtual representations of antique globes that can be described by the superordinate concept of virtual *** concept comprises facilities of data acquisition of the original globe,ways of visualising the digitised globe and its final cartographic *** that arise from this procedure are exemplified through both virtual hyperglobes and tactile *** findings on a 16th century earth globe are encouraging results of the presented virtual representation approach,which may offer a sustainable visualisation platform of interdisciplinary research.

关键词： 3D facsimile digital globe hyperglobe 3D visualisation digital restoration