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Simultaneous Effects of Impurity and Electric Field on Entropy Behavior in Double Cone-Like Quantum Dot

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Communications in Theoretical Physics 2018年第1期69卷 95-100页

作者： r.Khordad h.r.rastegar Sedehi h.Bahramiyan Department of Physics College of Sciences Yasouj University Department of Physics Jahrom University Department of Optics and Laser Engineering Marvdasht Branch Islamic Azad University

In this work, the simultaneous effects of electric field and impurity on the non-extensive entropy of a GaAs/Ga;In;As double cone-like quantum dot that is grown on a Ga As wet layer are studied. The system is under an external electric field directed along the-x direction. First, we have solved the Schr¨odinger equation using the finite element method. Then, we have used the Tsallis formalism and calculated the entropy of the system for different temperatures, electric fields and impurity locations. It is found that the entropy decreases with increasing the electric field and temperature. Since the electric field directed along the-x direction, the entropy reduces when the impurity moves toward the left hand side.

关键词： entropy double quantum dot electric field

Barut-Girardello and Gilmore-Perelomov coherent states for pseudoharmonic oscillators and their nonclassical properties: Factorization method

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Chinese Physics B 2013年第8期22卷 421-428页

作者： M K Tavassoly h r Jalali Atomic and Molecular Group Faculty of Physics Yazd UniversityYazd Iran Photonics research Group Engineering Research Center Yazd UniversityYazd Iran The Laboratory of Quantum Information Processing Yazd UniversityYazd Iran

In this paper we try to introduce the ladder operators associated with the pseudoharmonic oscillator, after solving the corresponding Schrrdinger equation by using the factorization method. The obtained generalized raising and lowering operators naturally lead us to the Dirac representation space of the system which is much easier to work with, in comparison to the functional hilbert space. The SU（1, 1） dynamical symmetry group associated with the considered system is exactly established through investigating the fact that the deduced operators satisfy appropriate commutation relations. This result enables us to construct two important and distinct classes of Barut-Girardello and Gilmore-Perelomov coherent states associated with the system. Finally, their identities as the most important task are exactly resolved and some of their nonclassical properties are illustrated, numerically.

关键词： pseudoharmonic oscillator factorization method Barut-Girardello coherent states Gilmore-Perelomov coherent states nonclassical properties

Electro-optical properties and(E,F) phase diagram of fluorinated chiral smectic liquid crystals

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Chinese Physics B 2018年第10期27卷 570-577页

作者： r Zgueb h Dhaouadi T Othman Universite Tunis El-Manar Faculte des Sciences de Tunis Laboratoire de physique de la matiere molle et de modelisation electromagnetique (LP3ME) Campus Universitaire Farhat Hached 2092 Tunis Tunisie

Fluorinated smectic liquid crystals each with a biphenyl benzoate rigid core are investigated. Molecular structures of the studied compounds have difference only in fluorine position and the length of the carbon chain. Dielectric relaxation study and electro-optical measurements are carried out with the classical SSFLC geometry. The field-induced phase transitions are studied and the（E,T） phase diagram is established.

关键词： smectic liquid crystal dielectric relaxation electro-optical properties phase transition (E,T)phase diagram

Vibration of quadrilateral embedded multilayered graphene sheets based on nonlocal continuum models using the Galerkin method

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Acta Mechanica Sinica 2011年第6期27卷 967-976页

作者： h.Babaei A.r.Shahidi Department of Mechanical Engineering Isfahan University of Technology

Free vibration analysis of quadrilateral multilayered graphene sheets（MLGS） embedded in polymer matrix is carried out employing nonlocal continuum *** principle of virtual work is employed to derive the equations of *** Galerkin method in conjunction with the natural coordinates of the nanoplate is used as a basis for the *** dependence of small scale effect on thickness,elastic modulus,polymer matrix stiffness and interaction coefficient between two adjacent sheets is *** non-dimensional natural frequencies of skew,rhombic,trapezoidal and rectangular MLGS are obtained with various geometrical parameters and mode numbers taken into account,and for each case the effects of the small length scale are investigated.

关键词： Small scale Free vibration. Quadrilateral multilayered graphene sheet. Polymer matrix. Nonlocal elasticity theory

Field-dependent resistive transitions in YBa_2Cu_3O_(7-δ) thin films:Influence of the pseudogap on vortex dynamics

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Chinese Physics B 2015年第1期24卷 467-473页

作者： S h Naqib r S Islam Department of Physics University of RajshahiRajshahi-6205 Bangladesh

The nature of resistive transition of high-quality crystalline thin films of YBa2Cu3O7-δhas been studied under magnetic fields（h） applied along the c direction over a wide range of doped holes, p, in the Cu O2 planes. The field- and temperature-dependent in-plane resistivity, ρab（T, h）, has been analyzed within the thermally assisted flux-flow（TAFF）formalism. The flux activation energy, U（T, h）, has been extracted from this analysis. The low-T part of the ρab（T, h）data can be described by an activation energy having the functional form of U（T, h） =（1- t）m（h-0/h）β, where t = T /Tc（reduced temperature）, and h0 is a field scale that primarily determines the magnitude of U（T, h）. The temperature exponent, m, shows a systematic variation with p, whereas the field exponent, β, is insensitive to the p values and is close to unity. The h0, on the other hand, changes rapidly as p is varied. U（T, h） is linked to the pinning potential and consequently on the superconducting condensation energy. Since the normal state pseudogap directly affects superconducting condensation energy, a clear correspondence between h0 and the PG energy scale, ε g, is found. Possible implications of these results are discussed.

关键词： Y123 superconductors thermally assisted flux-flow model activation energy pseudogap

Childhood constipation as an emerging public health problem

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World Journal of Gastroenterology 2016年第30期22卷 6864-6875页

作者： Shaman rajindrajith Niranga Manjuri Devanarayana Bonaventure Jayasiri Crispus perera Marc Alexander Benninga Department of Paediatrics Faculty of Medicine University of Kelaniya Department of Physiology Faculty of Medicine University of Kelaniya Consultant Paediatrician Asiri Hospital Department of Paediatric Gastroenterology and Nutrition Emma Children’s Hospital Academic Medical Centre

Functional constipation(FC) is a significant health problem in children and contrary to common belief, has serious ramifications on the lives of children and their families. It is defined by the rome criteria which encourage the use of multiple clinical features for diagnosis. FC in children has a high prevalence(0.7%-29%) worldwide, both in developed and developing countries. Biopsychosocial risk factors such as psychological stress, poor dietary habits, obesity and child maltreatment are commonly identified predisposing factors for FC. FC poses a significant healthcare burden on the already overstretched health budgets of many countries in terms of out-patient care, in-patient care, expenditure for investigations and prescriptions. Complications are common and range from minor psychological disturbances, to lower health-related quality of life. FC in children also has a significant impact on families. Many paediatric clinical trials have poor methodological quality, and drugs proved to be useful in adults, are not effective in relieving symptoms in children. A significant proportion of inadequately treated children have similar symptoms as adults. These factors show that constipation is an increasing public health problem across the world with a significant medical, social and economic impact. This article highlights the potential public health impact of FC and the possibility of overcoming this problem by concentrating on modifiable risk factors rather than expending resources on high cost investigations and therapeutic modalities.

关键词： Constipation Public health risk factors Prevention

Tunneled biopsy is an underutilised,simple,safe and efficient method for tissue acquisition from subepithelial tumours

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World Journal of Clinical Cases 2021年第21期9卷 5822-5829页

作者： Andreas Koutsoumpas ruwan perera Adele Melton Jonathan Kuker Tilak Ghosh Barbara Braden Translational Gastroenterology Unit Oxford University Hospitals NHS Foundation TrustOxford OX39DUUnited Kingdom Senior School Magdalen College SchoolOxford OX40DZUnited Kingdom Translational Gastroenterology Unit Oxford University Hospital NHS Foundation TrustOxford OX39DUUnited Kingdom

BACKGrOUND Tissue acquisition from subepithelial lesions is often attempted by endoscopic ultrasound(EUS)-sampling as conventional endoscopic biopsy usually fails to reach deeper layers of the gastrointestinal *** To investigate the utilisation,safety and diagnostic yield of an intensified“biteon-bite”tunnel biopsy *** In this retrospective cohort study,all patients presenting with subepithelial masses in the upper gastrointestinal tract from March 2013 to July 2019 were *** were analysed for size and location of the subepithelial mass,use of intensified tunnel biopsy protocol(more than 10 double bite-on-bite biopsies)or superficial conventional biopsies,histology and imaging results,occurrence of readmission and adverse events after *** Two hundred and twenty-nine patients with subepithelial lesions were *** conventional biopsies were taken in 117 patients and were diagnostic only in one lipoma(0.9%).Tunnel biopsies taken in 112/229(48.9%)patients were significantly more likely to provide histological diagnosis(53.6%;Pr lesions≥10mm the diagnostic yield of tunnel biopsies further increased to 41/67(61.2%).No immediate or delayed complications were *** 8 of the 51 endoscopists(15.7%)regularly attempted tunnel *** Tunnel biopsy is a simple,safe and efficient but underutilised diagnostic modality for tissue acquisition in subepithelial *** should be routinely attempted at the initial endoscopy.

关键词： Gastrointestinal stromal tumour Fine needle biopsy Lipoma Immunohistology Neuroendocrine tumours Fine needle biopsy

Bistability in a hybrid Optomechanical System under the Effect of a Nonlinear Medium

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Chinese Physics Letters 2017年第8期34卷 71-75页

作者： A. Asghari Nejad h. r. Askari h. r. Baghshahi Department of Physics Faculty of Science Vali-e-Asr University of Rafsanjan Rafsanjan 77176 Iran

We investigate a hybrid optomechanical system consisting of two coupled cavities, one of them is composed of two-end fixed mirrors （called the traditional cavity）, and the other has a one-end oscillating mirror （named as the optomechanical cavity）. A Kerr medium is inside the traditional cavity to enhance the nonlinearity due to the fact that it can cause observing of bistable behavior in intracavity intensity for the optomechanical cavity. The hamiltonian of the system is written in a rotating frame and its dynamics is described by quantum Langevin equations of motion. Our proposed system exhibits unconventional plots for the mean photon number of the optomechanical cavity which are not observed in previous works. The present results show a deep effect of the Kerr medium on optical bistability of intracavity intensity for the optomechanical cavity. Also, coupling strength of the cavities can effectively change the stability of the system.

关键词： Bistability in a hybrid Optomechanical System under the Effect of a Nonlinear Medium

Effect of Initial Grain Size on the hot Deformation Behavior and Microstructural Evolution of Pure Copper

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 662-678页

作者： h.r.rezaei Ashtiani A.A.Shayanpoor School of Mechanical Engineering Arak University of Technology38135-1177ArakIran

The influences of initial grain size(IGS)with 20μm and 50μm on the hot flow behavior and microstructural changes of pure copper were investigated using hot compression tests at a temperature range of 623–1073 K and strain rate range of 0.001–0.1 s^(-1).The effects of critical stress and corresponding critical strain were studied based on the internal and external processing *** critical stress and strain decreased with increasing temperature and decreasing strain *** investigation results of the microstructure and true strain–stress diagrams showed that dynamic recovery,dynamic recrystallization(DrX),and twinning mechanisms were caused during the hot deformation of pure *** evolution indicated some DrXed fine-grain took place around grain boundary of hot deformed samples with IGS of 20μm whereas DrXed fine-grain took place in interior grains for samples with larger *** results also showed that grain growth is also dependent on IGS as the grain growth rate for samples with the larger IGS is greater than the smaller *** critical strain rate and the temperature were obtained at 0.01 s^(-1) and 973 K,respectively,for the sudden change in the grain growth ***,twinning highly depended on IGS which almost did not happen in fine grain size while the volume fraction of twinning increased with increasing grain size.

关键词： Initial grain size hot deformation Pure copper Microstructure Dynamic recrystallization(DrX) Twinning