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SUSY QM in a One-Dimensional Box and Local Observable Quantities

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Chinese Physics Letters 2006年第8期23卷 1969-1972页

作者： Salvatore de Vincenzo escuela de fisica Facultad de Ciencias Universidad Central de Venezuela A.P. 47145 Caracas 1041-A Venezuela

We investigate several Hamiltonians for a free particle in a one-dimensional box, in the context of supersymmetric quantum mechanics. Specifically, we study this problem with the Neumann boundary condition, the periodic and antiperiodic boundary condition, and some mixed and complex boundary conditions. This is achieved by using an approach recently proposed which expresses the factorization of the partner Hamiltonians in terms of the probability density and current for the ground-state eigenfunction of one of them.

关键词： SUPERSYMMETRIC QUANTUM-MECHANICS BOUNDARY-CONDITIONS ENERGY-SPECTRA SUPERPOTENTIALS FACTORIZATION POTENTIALS PARTICLE SYSTEMS

First-principle calculations of magnetic properties of Ho_(6)(Fe,Mn)Bi_(2)compounds

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Rare Metals 2024年第11期43卷 6034-6047页

作者： Angel J.Garcia-Adeva Estibaliz Apinaniz Aritz Herrero Ivan R.Aseguinolaza Alberto Oleaga departamento de fisica Aplicada Escuela de Ingenieria de V itoria-GasteizUniversidad del Pais V asco UPV/EHU01006 V itoria-GasteizSpain departamento de fisica Aplicada Escuela de Ingenieria de BilbaoUniversidad del Pais V asco UPV/EHU48013 BilbaoSpain

The magnetic properties of Ho_(6)MnBi_(2)and Ho_(6)FeBi_(2)crystals are investigated by means of density functional *** materials are currently an active subject of research in the context of magnetic refrigeration applications since they exhibit a remarkable magnetocaloric *** this work,the equation of state,density of states and magnetic moments are calculated and compared with previous experimental results for these ***,the Curie temperatures for the paramagnetic to ferromagnetic phase transition observed in these systems are calculated from first *** the calculated quantities are in reasonable agreement with experimental data,which suggests that density functional theory could provide a reliable framework to theoretically investigate the magnetic properties of intermetallic ternary compounds.

关键词： Intermetallic compounds Rare earths Magnetic properties Magnetocaloric effect density functional theory Heisenberg model

Explicit Relations of Physical Potentials Through Generalized Hypervirial and Kramers' Recurrence Relations

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Communications in Theoretical Physics 2015年第6期63卷 682-686页

作者：孙国华董世海 Catedra CONACyT Centro de Investigacion en ComputacionInstituto Politecnico Nacional departamento de fisica Escuela Superior de Ffsica y MatematicasInstituto Politecnico Nacional

Based on a Hamfltonian identity, we study one-dimensional generalized hypervirial theorem, Blanchardlike （non-diagonal case） and Kramers＇（diagonal case） recurrence relations for arbitrary x^k which is independent of the central potential V（x）. Some significant results in diagonal case are obtained for special k in xk （k ≥2）. In particular, we find the orthogonal relation 〈n1｜n2〉 = δh1,n2 （k = 0）, 〈n1[V＇（x）｜n2〉 = （En1-En2）^2〈n1｜x｜n2〉（k = 1）, En = （n｜V＇（x）x/2｜n〉＋（n｜V（x）｜n〉（k = 2） and -4En（n｜x｜n） ~ 〈n｜V＇（x）x^2｜n〉＋ 4〈n｜V（x）x｜n〉 =0 （k=3）. The latter two formulas can be used directly to calculate the energy levels. We present useYul explicit relations for some well known physical potentials without requiring the energy spectra of quantum system.

关键词： Hamiltonian identity hypervirial relations Kramers' recurrence relation physical potentials

Spin Number Coherent States and the Problem of Two Coupled Oscillators

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Communications in Theoretical Physics 2015年第7期64卷 34-38页

作者： D.Ojeda-Guillén R.D.Mota V.D.Granados escuela Superior de fisica y Matemáticas Instituto Politécnico Nacional Ed. 9 Unidad Profesional Adolfo López Mateos escuela Superior de Ingenieria Mecánica y Eléctrica Unidad Culhuacán Instituto Politécnico Nacional

From the definition of the standard Perelomov coherent states we introduce the Perelomov number coherent states for any su(2) Lie algebra. With the displacement operator we apply a similarity transformation to the su(2)generators and construct a new set of operators which also close the su(2) Lie algebra, being the Perelomov number coherent states the new basis for its unitary irreducible representation. We apply our results to obtain the energy spectrum, the eigenstates and the partition function of two coupled oscillators. We show that the eigenstates of two coupled oscillators are the SU(2) Perelomov number coherent states of the two-dimensional harmonic oscillator with an appropriate choice of the coherent state parameters.

关键词： coherent states Lie algebras coupled oscillators

Influence of parameters on the microstructure of a duplex stainless steel joint welded by a GMAW welding process

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Progress in Natural Science:Materials International 2022年第4期32卷 415-423页

作者： Sandra Chacón-Fernández Antonio Portolés García Gerardo Romaní Labanda Universidad Politécnica de Madrid Escuela Técnica Superior de Ingenieros Industriales UPM

Duplex stainless steels（DSSs） are widely used in industry for their desirable properties. Any fusion welding technique modifies the microstructure and, consequently, the properties of the material. This paper presents a parametric study of the variables that determine the energy contribution（current, voltage and welding speed） and the structural modifications produced during gas metal arc welding. The analysis comprises metallographic study,phase balance, dimensioning of the weld beads and tensile and hardness tests. The influence of the variables studied on the thermal cycles obtained（temperatures reached and cooling rate） was determined by using a finite element model. The results showed that, in addition to the indicated parameters, the parameter power transfer per volume（W/m3） and the geometry in the bead must be controlled due to their influence on the heat flow distribution and phase balance.

关键词： Welding Heat input GMAW Duplex stainless steels (DSS) Finite element model (FEM)

Skew-symmetric Elements in Nonlinear Involutions in Group Rings

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Algebra Colloquium 2015年第2期22卷 321-332页

作者： A.P. Raposo escuela Universitaria de Arquitectura Tecnica Universidad Politecnica de Madrid Madrid Spain

Given an involution in a group G, it can be extended in various ways to an involution in the group ring RG, where R is a ring, not necessarily commutative. In this paper nonlinear extensions are considered and necessary and sufficient conditions are given on the group G, its involution, the ring R and the extension for the set of skew-symmetric elements to be commutative and for it to be anticommutative.

关键词： group ring involution skew-symmetric element

AN OPTIMAL CONTROL PROBLEM FOR A LOTKA-VOLTERRA COMPETITION MOdeL WITH CHEMO-REPULSION

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Acta Mathematica Scientia 2024年第2期44卷 721-751页

作者： Diana I.HERNÁNdeZ Diego A.RUEDA-GOMEZ Élder J.VILLAMIZAR-ROA Universidad Industrial de Santander Escuela de MatemáticasA.A.678BucaramangaColombia

In this paper we study a bilinear optimal control problem for a diffusive Lotka-Volterra competition model with chemo-repulsion in a bounded domain of ℝ^(ℕ),N=2,*** model describes the competition of two species in which one of them avoid encounters with rivals through a chemo-repulsion *** prove the existence and uniqueness of weak-strong solutions,and then we analyze the existence of a global optimal solution for a related bilinear optimal control problem,where the control is acting on the chemical ***,we derive first-order optimality conditions for local optimal solutions using the Lagrange multipliers ***,we propose a discrete approximation scheme of the optimality system based on the gradient method,which is validated with some computational experiments.

关键词： Lotka-Volterra chemo-repulsion optimal control optimality conditions

The first meteorological observations at a tropical high elevation site:Antisana,1846

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Journal of Mountain Science 2016年第6期13卷 1047-1055页

作者： Aria Ma M.FARRONA Fernando DOMINGUEZ-CASTRO Ma Cruz GALLEGO Jose M.VAQUERO departamento de fisica Facultad de CienciasUniversidad de ExtremaduraBadajoz 06071Spain Instituto de fisica de Cantabria(UC-CSIC) Santander 39005Spain departamento de Ingenieria Civily Ambiental Escuela Politecnica NacionalQuito 170112Ecuador Instituto Nacional de Meteorologiae Hidrologia Quito 170135Ecuador instituto universitario de investigación del agua cambio climático y sostenibilidad (iacys) universidad de extremaduraBadajoz 06071，Spain departamento de física centro universitario de mérida universidad de extremaduraMerida 06800Spain

Antisana is a stratovolcano with an associated glacier located in the Ecuadorian Andes. Dr Aguirre made meteorological readings every day, at every hour from sunrise to sunset, from december 1845 to december 1846, at Antisana using a meteorological station at 4060 mamsl （meters above mean sea level）. Unfortunately, only the monthly average data have been preserved. These meteorological data are here studied and compared with the closest modern stations for monthly values of temperature, rainfall, and pressure. According to these comparisons, the year 1846 was rainy and cold in comparison with the current climate. Moreover, these observations have been useful to help resolve a debate about a possible E1Nifio event in 1846 with the high precipitation in Antisana and Quito in 1846 discarding the occurrence of an E1 Nifio event. The probable occurrence of a La Nifia event is discussed. These data are the earliest known systematic instrumental meteorological observations taken at above 4000 mamsl.

关键词： Early instrumental records Glacier Pastclimate conditions

Stress tensors and quantification of fracture patterns to analyze connectivity and potential fluid flow in a mesa landform of the Northern Andes

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Journal of Mountain Science 2024年第1期21卷 271-291页

作者： GARCÍA-ARIAS Sergio VELANDIA Francisco ALVAREZ Angélica SANABRIA-GÓMEZ JoséD TARAZONA Yessenia VARGAS María Camila escuela de Geología Universidad Industrial de SantanderCra.27 Calle 9BucaramangaColombia escuela de Física Universidad Industrial de SantanderCra.27 Calle 9BucaramangaColombia

This work applies stress tensors inversions and quantification of fracture patterns along the Mesa de Los Santos, in the Eastern Cordillera of Colombia, to better understand the potential fluid flow. It thus contributes to the conceptual hydrogeological model. The area was subdivided into three blocks, separated by the NW Potreros and the Los Santos faults, having minor inner faults of different orientations. This separation facilitates the analysis of the fractures measured in the field, which in general show high dip angles and a conjugate geometry in the northern block, tension fractures(Mode I) in the central block, and a random distribution in the southwestern block. WinTensor treatment of slickensides yielded a maximum horizontal stress(SHmax) of 111o, which coincides with the WNW-ESE tensor observed from the conjugate and tension joints. We then used Frac Pa Q to generate interpolation maps of fracture intensity and density. The maps show the highest values in the central block and the lowest in the northern block,where the precipitation is higher, causing intensive rock weathering and homogenization of the fracture planes. Although the highest values of connectivity by line are found to the south of the mesa, we suggest the possibility of greater flow from the recharge zone(NE) along bedding planes and open NW-SE fractures.

关键词： Mesa de Los Santos Colombia Win-Tensor FracPaQ Strike-slip faults Fractured aquifers