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Chinese Physics B 2020年第4期29卷 179-189页

作者： s m Ngounou f B Pelap Unite de Recherche de mecanique et de modelisation des systèmes Physiques(UR-2 msP) Faculte des SciencesUniversite de DschangBP 69 DschangCameroun Unite de Recherche de matiere Condensee d'Electronique et de Traitement du signal(UR-mACETs) Faculte des SciencesUniversite de DschangBP 67 DschangCameroun

The dynamics of modulated waves in a nonlinear bi-inductance transmission line with dissipative elements are *** show the existence of two frequency modes and carry out intensive investigations on the low frequency *** to the multiple scales method,the behavior of these waves is investigated and the dissipative effects are *** appears that the dissipation coefficient increases with the carrier wave *** the continuous approximation,we derive that the propagation of these waves is governed by the complex Ginzburg-Landau equation instead of the Korteweg-de-Vries equation as previously *** studies of the dynamics of plane waves in the line reveal the existence of three additional regions in the dispersion curve where the modulational phenomenon is *** the low frequency mode,we demonstrate that the network allows the propagation of dark and bright *** findings are in perfect agreement with the analytical predictions.

关键词： dissipative bi-inductance network low frequency mode continuous approximation complex Ginzburg-Landau equation

Dynamics of high-frequency modulated waves in a nonlinear dissipative continuous bi-inductance network

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Chinese Physics B 2021年第6期30卷 193-205页

作者： s m Ngounou f B Pelap Unitéde Recherche de mécanique et de modélisation des systèmes Physiques(UR-2 msP) Facultédes SciencesUniversitéde DschangBP 69 DschangCameroun Unitéde Recherche de matière Condensée d'Electronique et de Traitement du signal(UR-mACETs) Facultédes SciencesUniversitéde DschangBP 67 DschangCameroun

This paper presents intensive investigation of dynamics of high frequency nonlinear modulated excitations in a damped bimodal lattice. The effects of the dissipation are considered through a linear dissipation coefficient whose evolution in terms of the carrier wave frequency is checked. There appears that the dissipation coefficient increases with the carrier wave frequency. In the linear limit and for high frequency waves, study of the asymptotic behavior of plane waves reveals the existence of two additional regions in the dispersion curve where the modulational phenomenon is observed compared to the lossless line. Based on the multiple scales method exploited in the continuum approximation using an appropriate decoupling ansatz for the voltage of the two different cells, it appears that the motion of modulated waves is described by a dissipative complex Ginzburg–Landau equation instead of a Korteweg–de Vries equation. We also show that this amplitude wave equation admits envelope and hole solitons in the high frequency mode. from basic sources, we design a programmable electronic generator of complex signals with desired characteristics, which delivers signals exploited as input waves for all our numerical simulations. These simulations are performed in the LTspice software that uses realistic components and give the results that corroborate perfectly our analytical predictions.

关键词： dissipative bi-inductance network high-frequency mode continuous approximation dissipative complex Ginzburg–Landau equation programmable electronic generator LT-Pspice observations

Getting physical with medical education:Exercise based virtual anatomy review classes for medical students

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World Journal of methodology 2025年第1期15卷 20-25页

作者： Nadeesha R samarasinghe Taniya s Nagpal michele L Barbeau Charys m martin Division of General surgery Faculty of MedicineUniversity of British ColumbiaVancouver V6T 1Z3BCCanada faculty of Kinesiology Sport and RecreationUniversity of AlbertaEdmonton T6G 2R3ABCanada Anatomy and Cell Biology University of Western OntarioLondon N6A 3K7ONCanada Department of Anatomy and Cell Biology Schulich School of Medicine and DentistryThe University of Western OntarioLondon N6A 3K7ONCanada

The benefits of regular physical activity are well ***,few studies have examined the effectiveness of integrating physical activity(PA)into curricula within a post-secondary *** investigate the incorporation of PA into medical curriculum,we developed a series of optional exercise-based review sessions designed to reinforce musculoskeletal(msK)anatomy course *** synchronous sessions were co-taught by a group fitness instructor and an anatomy *** fitness instructor would lead students through both strength and yoga style exercises,while the anatomy instructor asked questions about relevant anatomical structures related to course material previously *** the sessions,participants were asked to evaluate the classes on their self-reported exam preparedness in improving msK anatomy knowledge,PA levels,and mental *** participants completed surveys;a majority agreed that the classes increased understanding of msK concepts(90.0%)and activity levels(97.7%).many(70.0%)felt that the classes helped reduce *** majority of respondents(90.0%)agreed that the classes contributed to increased feelings of social ***,medical students saw benefit in PA based interventions to supplement msK course *** with increasing activity levels and promoting health behaviours,integrating PA into medical curriculum may improve comprehension of learning material,alleviate stress and foster social connectivity among medical students.

关键词： medical education musculoskeletal Anatomy Exercise Online learning

Analytical study of Cattaneo–Christov heat flux model for a boundary layer flow of Oldroyd-B fluid

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Chinese Physics B 2016年第1期25卷 657-662页

作者： f m Abbasi m mustafa s A shehzad m s Alhuthali T Hayat Department of mathematics Comsats Institute of lnformaHon TechnologyIslamabad 44000Pakistan school of Natural sciences(sNs) National University of Science and Technology(NUST)Islamabad 44000Pakistan Department of mathematics Comsats Institute of/nformation TechnologySahiwa157000Pakistan NAAm Research Group Department of MathematicsFaculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia Department of mathematics Quaid-I-Azam University 45320Islamabad 44000Pakistan

We investigate the Cattaneo-Christov heat flux model for a two-dimensional laminar boundary layer flow of an incompressible Oldroyd-B fluid over a linearly stretching sheet. mathematical formulation of the boundary layer problems is given. The nonlinear partial differential equations are converted into the ordinary differential equations using similarity transformatioris. The dimensionless velocity and temperature profiles are obtained through optimal homotopy analysis method （OHAm）. The influences of the physical parameters on the velocity and the temperature are pointed out. The results show that the temperature and the thermal boundary layer thickness are smaller in the Cattaneo-Christov heat flux model than those in the fourier＇s law of heat conduction.

关键词： Oldroyd-B fluid Cattaneo-Christov heat flux nonlinear analysis

Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAmI m.EfTEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(fGm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the fGm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of fGm composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in fGm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

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Compton profiles of NiO and TiO_2 obtained from first principles GWA spectral function

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Chinese Physics B 2016年第6期25卷 407-415页

作者： s m Khidzir m f m Halid W A T Wan Abdullah Department of Physics Universiti of Malaya

In this work,we first use momentum density studies to understand strongly correlated electron behavior,which is typically seen in transition metal *** observe that correlated electron behavior as seen in bulk NiO is due to the fermi break located in the middle of overlapping spectral functions obtained from a GW（G is Green’s function and W is the screened Coulomb interaction） approximation（GWA） calculation while in the case of TiO2 we can see that the origin of the constant momentum distribution in lower momenta is due to a pile up of spectra before the fermi *** observations are then used to compare our calculated Compton profiles with previous experimental studies of fukamachi and *** calculations for NiO are observed to follow the same trend as the experimental profile but it is seen to have a wide difference in the case of TiO2 before the fermi *** ground state momentum densities differ significantly from the quasiparticle momentum density,thus stressing the importance of the quasiparticle wave function as the input for the study of charge density and the electron localization *** we perform a calculation of the quasiparticle renormalization function,giving a quantitative description of the discontinuity of the GWA momentum density.

关键词： elastic and Compton scattering density functional theory local density approximation gradient and other corrections elements oxides nitrides borides carbides chalcogenides

Band structure,fermi surface,elastic,thermodynamic,and optical properties of AlZr3,AlCu3,and AlCu2Zr:first-principles study

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Chinese Physics B 2016年第8期25卷 103-112页

作者： Parvin R Parvin f Ali m s Islam A K m A Department of Physics Rajshahi University Rajshahi-6205 Bangladesh Department of Physics Pabna University of Science and Technology Pabna 6600 Bangladesh International Islamic University Chittagong 154/A College Road Chittagong-4203 Bangladesh

The electronic properties（fermi surface,band structure,and density of states（DOs）） of Al-based alloys Alm3（m=Zr and Cu） and AlCu2Zr are investigated using the first-principles pseudopotential plane wave method within the generalized gradient approximation（GGA）.The structural parameters and elastic constants are evaluated and compared with other available ***,the pressure dependences of mechanical properties of the compounds are *** temperature dependence of adiabatic bulk modulus,Debye temperature,specific heat,thermal expansion coefficient,entropy,and internal energy are all obtained for the first time through quasi-harmonic Debye model with phononic effects for T = 0 K-100 *** parameters of optical properties（dielectric functions,refractive index,extinction coefficient,absorption spectrum,conductivity,energy-loss spectrum,and reflectivity） of the compounds are calculated and discussed for the first *** reflectivities of the materials are quite high in the IR-visible-UV region up to ~ 15 eV,showing that they promise to be good coating materials to avoid solar *** of the properties are also compared with those of the Al-based Ni3 Al compound.

关键词： first principle calculations fermi surface elastic moduli entropy and internal energy optical properties

friction and wear properties of nano-si3N4/nano-siC composite under nanolubricated conditions

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Journal of Advanced Ceramics 2016年第2期5卷 145-152页

作者： m.s.CHAROO m.f.WANI Centre for Tribology Mechanical Engineering Department National Institute of Technology Srinagar(J&K) 190006 India

friction and wear properties of nano-si3N4/nano-siC composite were studied under nanolubricated conditions. mineral oil mixed with nanoparticles of diamond was used as lubricant. A friction coefficient of 0.043 and a ... 详细信息

friction and wear properties of nano-sisub>3sub>Nsub>4sub>/nano-siC composite were studied under nanolubricated conditions. mineral oil mixed with nanoparticles of diamond was used as lubricant. A friction coefficient of 0.043 and a wear coefficient of 4.2×10sup>-7sup> were obtained for nano-sisub>3sub>Nsub>4sub>/nano-siC composite under normal load of 600 N with mineral oil + 0.5 wt% nanodiamond, whereas a friction coefficient of 0.077 and a wear coefficient of 10.3×10sup>-7sup> were obtained for nano-sisub>3sub>Nsub>4sub>/nano-siC composite under normal load of 600 N with mineral oil. 3D surface profilometer was used to study the surface morphology of wear scars. scanning electron microscopy (sEm) and X-ray diffraction (XRD) studies were conducted to illustrate reduction in friction and wear.

关键词： nano-ceramics nanolubrication nano-si3N4/nano-siC friction wear

New Aspects of field Entropy squeezing as an Indicator for mixed state Entanglement in an Effective Two-Level system with stark shift

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Chinese Physics Letters 2011年第12期28卷 24-27页

作者： s.Abdel-Khalek m.m.A.Ahmed A-s f.Obada Department of mathematics Faculty of ScienceSohag University82524 SohagEgypt Department of mathematics Faculty of ScienceTaif University21974 TaifSaudi Arabia Department of mathematics Faculty of ScienceAl-Azhar UniversityNasr City11884 CairoEgypt

We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic field,initially prepared in a coherent *** entropy squeezing as an indicator of the entanglement in a mixed state system is *** temporal evolution of the negativity,Wehrl entropy,Wehrl phase distribution and field entropy squeezing are *** results highlight the important roles played by both the stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy,Wehrl phase distribution and field entropy squeezing.

关键词： state entropy system

OPTImIZATION Of THE sYNTHEsIs Of ACRYLAmIDE HYDROGEL BY γ-RAY IRRADIATION

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Chinese Journal of Polymer science 2004年第3期22卷 253-258页

作者： m.A. Chowdhury m.m. Alam m.f. mina f. Akhtar s.E. Kabir Department of Chemistry Faculty of Science Jahangir Nagar University Dhaka BangladeshNRCD INST AERE GPO Box-3787 Dhaka Bangladesh NRCD INST AERE GPO Box-3787 Dhaka Bangladesh NRCD INST AERE GPO Box-3787 Dhaka Bangladesh Department of Chemistry Faculty of Science Jahangir Nagar University Dhaka Bangladesh

Hydrogels have been synthesized from 10%, 20%, 30%, 40%, 50% and 60% aqueous solutions of acrylamide monomer by gamma radiation employing doses in the range of 0.2-30 kGy from a Co-60 source. The effect of solution concentration, γ-ray dose, pH and time was studied in order to observe the optimizing conditions in the characterization of hydrogels. Gel fraction increases with dose for all concentrations indicating hundred-percentage conversion of gel at doses 5 kGy for homogenous solutions in the range of 20%-50% concentration. On the other hand, 10% solution provides conversion less than 86% even at 30 kGy, whereas 60% monomer makes an inhomogeneous solution which stile gives about 100% gel fraction. swelling of hydrogels under water with respect to time varies with both the doses and concentrations due to the change of crosslinking density in the gels. The maximum volume change of hydrogels during swelling and water desorption mainly occurs within 24 h. swelling is also enhanced with the rise of pH due to change of ionic content of the solvent. Considering the amount of gel fraction and the properties of hydrogel, the samples prepared from 20% solution at 5 kGy show better results. moreover, the effect of bacteria on hydrogel was found to be nil, suggesting a prohibition of growth of microorganism in it.

关键词： Hydrogel Acrylamide γ-radiation swelling microorganism