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Effects of interface bound states on the shot noise in normal metal–low-dimensional Rashba semiconductor tunnel junctions with induced s-wave pairing potential

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Chinese Physics B 2019年第5期28卷 268-275页

作者： Wen-Xiang Chen Rui-Qiang Wang Liang-Bin Hu Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication Engineering South China Normal University

We consider the effects of interface bound states on the electrical shot noise in tunnel junctions formed between normal metals and one-dimensional(1 D) or two-dimensional(2 D) Rashba semiconductors with proximity-induced s-wave pairing potential. We investigate how the shot noise properties vary as the interface bound state is evolved from a non-zero energy bound state to a zero-energy bound state. We show that in both 1 D and 2 D tunnel junctions, the ratio of the noise power to the charge current in the vicinity of zero bias voltage may be enhanced significantly due to the induction of the midgap interface bound state. But as the interface bound state evolves from a non-zero energy bound state to a zero-energy bound state, this ratio tends to vanish completely at zero bias voltage in 1 D tunnel junctions, while in 2 D tunnel junctions it decreases smoothly to the usual classical Schottky value for the normal state. Some other important aspects of the shot noise properties in such tunnel junctions are also clarified.

关键词： interface bound state tunnel junction shot noise

Meta-optics and bound states in the continuum

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Science Bulletin 2019年第12期64卷 836-842页

作者： Kirill Koshelev Andrey Bogdanov Yuri Kivshar Nonlinear Physics Centre Australian National UniversityCanberra ACT 2601Australia ITMO University St. Petersburg 197101Russia

We discuss the recent advances in meta-optics and nanophotonics associated with the physics of bound states in the continuum(BICs). Such resonant states appear due to a strong coupling between leaky modes in optical guiding structures being supported by subwavelength high-index dielectric Mieresonant nanoantennas or all-dielectric metasurfaces. First, we review briefly very recent developments in the BIC physics in application to isolated subwavelength particles. We pay a special attention to novel opportunities for nonlinear nanophotonics due to the large field enhancement inside the particle volume creating the resonant states with high-quality(high-Q) factors, the so-called quasi-BIC, that can be supported by the subwavelength particles. Second, we discuss novel applications of the BIC physics to alldielectric optical metasurfaces with broken-symmetry meta-atoms when tuning to the BIC conditions allows to enhance substantially the Q factor of the flat-optics dielectric structures. We also present the original results on nonlinear high-Q metasurfaces and predict that the frequency conversion efficiency can be boosted dramatically by smart engineering of the asymmetry parameter of dielectric metasurfaces in the vicinity of the quasi-BIC regime.

关键词： bound states in the continuum Meta-optics Second-harmonic generation Nanoresonator Metasurfaces

Upper bound analysis for deep tunnel face with joined failure mechanism of translation and rotation

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Journal of Central South University 2015年第11期22卷 4310-4317页

作者：许敬叔杜佃春杨子汉 School of Civil Engineering Central South University

A joined failure mechanism of translation and rotation was proposed for the stability analysis of deep tunnel face, and the upper bound solution of supporting force of deep tunnel was calculated under pore water pressure. The calculations were based on limit analysis method of upper bound theory, with the employment of non-associated Mohr-Coulomb flow rule. Nonlinear failure criterion was adopted. Optimized analysis was conducted for the effects of the tunnel depth, pore water pressure coefficient, the initial cohesive force and nonlinear coefficient on supporting force. The upper bound solutions are obtained by optimum method. Results are listed and compared with the previously published solutions for the verification of correctness and effectiveness. The failure shapes are presented, and results are discussed for different pore water pressure coefficients and nonlinear coefficients of tunnel face.

关键词： deep tunnel upper bound translation and rotation w

The upper bound function of nonadiabatic dynamics in parametric driving quantum systems

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Chinese Physics B 2019年第8期28卷 31-41页

作者： Lin Zhang Junpeng Liu School of Physics and Information Technology Shaanxi Normal University

The adiabatic control is a powerful technique for many practical applications in quantum state engineering,light-driven chemical reactions and geometrical quantum *** paper reveals a speed limit of nonadiabatic transition in a general time-dependent parametric quantum system that leads to an upper bound function which lays down an optimal criteria for the adiabatic *** upper bound function of transition rate between instantaneous eigenstates of a time-dependent system is determined by the power fluctuations of the system relative to the minimum gap between the instantaneous *** a parametric Hilbert space,the driving power corresponds to the quantum work done by the parametric force multiplying the parametric velocity along the parametric driving *** general two-state time-dependent models are investigated as examples to calculate the bound functions in some general driving schemes with one and two driving *** calculations show that the upper bound function provides a tighter real-time estimation of nonadiabatic transition and is closely dependent on the driving frequencies and the energy gap of the *** deviations of the real phase from Berry phase on different closed paths are induced by the nonadiabatic transitions and can be efficiently controlled by the upper bound *** the upper bound is adiabatically controlled,the Berry phases of the electronic spin exhibit nonlinear step-like behaviors and it is closely related to topological structures of the complicated parametric paths on Bloch sphere.

关键词： adiabatic dynamics parametric driving upper bound function

bound lipids in lacustrine sediments in Guchenghu Lake, East China

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Chinese Science Bulletin 1997年第21期42卷 1817-1820页

作者： Zhang, G Sheng, GY Fu, JA Chinese Acad Sci Guangzhou Inst Geochem Guangzhou 510640 Peoples R China

BIOMARKERS used as indicators of the paleoclimatic and paleoenvironmental changes are re-quired to be bio-specific in origin and be stable in the early diagenesis process. The input ofplenty of land-derived organics, as well as possible changes in the early diagenesis process,made the lipid composition of inland lacustrine sediments more complicated, and, as a result,the bio-indicating significance of some biomarkers often become obscured. Except for

关键词： bound lipids composition sources paleoenvironmental changes.

Combined load bearing capacity of rigid piles embedded in a crossanisotropic clay deposit using 3D finite element lower bound

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 717-737页

作者： Ardavan Izadi Reza Jamshidi Chenari Department of Civil Engineering Faculty of EngineeringUniversity of GuilanRashtGuilanIran

In this study,an iterative-based three-dimensional finite element lower bound in association with the second-order cone programming method is adopted to evaluate the limit load of a single pile embedded in cross-anisotropic soils under general loading *** lower bound solutions of the pile embedded in an anisotropic soil deposit can be found by formulating the element equilibrium,equilibrium of shear and normal stresses along discontinuities,boundary conditions,yield function,and optimizing the objective function through the second-order cone programming method in conjunction with an iterative-based update procedure.A general loading condition is considered to profile the expansion of the safe load in the vertical-horizontal-moment(V-H-M)*** results of this study are compared and validated against three different cases including an isotropic lateral loading,anisotropic end bearing capacity,and a pile embedded in an isotropic soil deposit under general loading condition.A parametric study is conducted to evaluate the impact of different influencing *** was found that the effect of anisotropy on the variation of lateral limit load of a single pile is more pronounced than the corresponding vertical and bending moment limit loads,whereas the interface properties have more significant effects on the vertical and bending moment limit loads in comparison to the lateral limit load.

关键词： Rigid pile Cross-anisotropy Clay Combined loading Three-dimensional finite element lower bound

UPPER bound METHOD FOR SINTERED POWDER MATERIALS IN PLANE STRAIN

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中国有色金属学会会刊：英文版 1994年第2期4卷 86-91页

作者： Hua, Lin Zhao, Zhongzhi Wuhan Inst of Technology Wuhan China

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关键词： sintered powder material upper bound method plane strain

On the Role of Differentiation Parameter in a bound State Solution of the Klein-Gordon Equation

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Communications in Theoretical Physics 2019年第3期71卷 267-273页

作者： B.C.Lütfüo?lu Department of Physics Faculty of Science Akdeniz University Department of Physics Faculty of Science University of Hradec Králové

Recently, the bound state solutions of a confined Klein-Gordon particle under the mixed scalar-vector generalized symmetric Woods-Saxon potential in one spatial dimension have been investigated. The obtained results reveal that in the spin symmetric limit discrete spectrum exists, while in the pseudo-spin symmetric limit it does *** this manuscript, new insights and information are given by employing an analogy of the variational principle. The role of the difference of the magnitudes of the vector and scalar potential energies, namely the differentiation parameter,on the energy spectrum is examined. It is observed that the differentiation parameter determines the measure of the energy spectrum density by modifying the confined particle's mass-energy in addition to narrowing the spectrum interval length.

关键词： Klein-Gordon equation generalized symmetric Woods-Saxon potential bound st ate spectrum spin symmetry limit analytic solutions

The Buchdahl stability bound in Eddington-inspired Born-Infeld gravity

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Chinese Physics C 2019年第8期43卷 86-92页

作者： Wei-Xiang Feng Chao-Qiang Geng Ling-Wei Luo Department of Physics and Astronomy University of CaliforniaRiversideCalifornia 92521 Department of Physics National Tsing Hua UniversityHsinchu 300 Physics Division National Center for Theoretical SciencesHsinchu 300 Synergetic Innovation Center for Quantum Effects and Applications (SICQEA) Hunan Normal UniversityChangsha 410081 Institute of Physics Academia SinicaTaipei 11529

We give the Buchdahl stability bound in Eddington-inspired Born-Infeld(EiBI)*** show that this bound depends on an energy condition controlled by the model parameter *** this bound,we can constrain κ≤10~8 m^2 if a neutron star with a mass around 3 M is observed in the *** addition,to avoid the potential pathologies in EiBI,a Hagedorn-like equation of state associated with κ at the center of a compact star is inevitable,which is similar to the Hagedorn temperature in string theory.

关键词： Eddington-inspired Born-Infeld gravity Buchdahl stability bound Hagedom-like equation of state compact stars