检索结果-南通市图书馆

IEEE/CAA Journal of Automatica sinica 2018年第1期5卷 360-366页

作者： m.D.s.Aliyu Department of Electrical Engineering King Faisal University Al-Ahsa 31982 Saudi Arabia IEEE

In this paper, we propose an iterative relaxation method for solving the Hamilton-Jacobi-Bellman-Isaacs equation(HJBIE) arising in deterministic optimal control of affine nonlinear systems. Local convergence of the method is established under fairly mild assumptions, and examples are solved to demonstrate the effectiveness of the method. An extension of the approach to Lyapunov equations is also discussed. The preliminary results presented are promising, and it is hoped that the approach will ultimately develop into an efficient computational tool for solving the HJBIEs.

关键词： Affine nonlinear system bounded continuous function convergence Hamilton-Jacobi-Bellman-Isaacs equation Lyapunov equation relaxation method Riccati equation

Dynamics of entanglement protection of two qubits using a driven laser field and detunings:Independent and common,markovian and/or non-markovian regimes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第4期27卷 170-177页

作者： s Golkar m K Tavassoly Atomic and molecular Group Faculty of PhysicsYazd University

Preventing quantum entanglement from decoherence effect is of theoretical and practical importance in the quantum information processing *** this regard,we consider the entanglement dynamics of two identical qubits where the qubits which are coupled to two independent（markovian and/or non-markovian） as well as a common reservoir at zero temperature are further interacted with a classical driving laser ***,we study the preservation of generated two-qubit entanglement in various situations using the concurrence *** is shown that by applying the classical driving field and so the possibility of controlling the Rabi frequency,the amount of entanglement of the two-qubit system is improved in the off-resonance condition between the qubit and the central cavity frequencies（central detuning） in both non-markovian and markovian *** the central detuning has a constructive role,the detuning between the qubit and the classical field（laser detuning） affects negatively on the entanglement *** obtained results show that long-living entanglement in the non-markovian reservoir is more accessible than in the markovian *** demonstrate that,in a common reservoir non-zero stationary entanglement is achievable whenever the two-qubit system is coupled to the reservoir with appropriate values of relative coupling strengths.

关键词： entanglement markovian and non-markovian reservoir Rabi frequency concurrence

mφller Energy-momentum Complex in General Relativity for Higher Dimensional Universes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2007年第7期24卷 1821-1824页

作者： m. Aygiin s. Aygiin i. Yflmaz H. Baysal i. Tarhan Department of Physics Art and Science Faculty Canakkale Onsekiz Mart University 17020 Canakkale Thrkey Department of secondary science and mathematics Education Faculty of Education~anakkale Onsekiz Mart University 17100 Canakkale Turkey

Using the mφ11er energy-momentum definition in general relativity （GR） we calculate the total energy-momentum distribution associated with （n 4- 2）-dimensional homogeneous and isotropic model of the universe. It is found that total energy of m^ller is vanishing in （n 4- 2） dimensions everywhere but n-momentum components of mφ11er in （n 4- 2） dimensions are different from zero. Also, we evaluate the static Einstein Universe, FRW universe and de sitter universe in four dimensions by using （n 4- 2）-type metric, then calculate the mφ11er energy-momentum distribution of these spacetimes. However, our results are consistent with the results of Banerjee and sen, Xulu, Radinschi, Vargas, Cooperstock-Israelit, A ygiin et al., Rosen, and Johri et al. in four dimensions.

关键词： Energy-momentum Relativity Dimensional

Laser-induced thermal lens study of the role of morphology and hydroxyl group in the evolution of thermal diffusivity of copper oxide

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 588-593页

作者： Riya sebastian m s swapna Vimal Raj s sankararaman Department of Optoelectronics University of KeralaTrivandrum 695581KeralaIndia

The paper explores the evolution of thermal behavior of the material by studying the variations in thermal diffusivity using the single beam thermal lens(TL) technique. For this purpose, the decomposition of Cu(OH)_(2) into CuO is studied in a time range up to 120 h, by subjecting the sample to morphological, structural, and spectroscopic characterizations. The time evolution of thermal diffusivity can be divided into three regions for demonstrating the dynamics of the reaction. When the reaction is complete, the thermal diffusivity is also found to be saturated. In addition to the morphological modifications,from rods to flakes, the variations in the amount of hydroxyl group are attributed to be responsible for the enhancement of base fluid's thermal diffusivity by 165%. Thus the study unveils the role of hydroxyl groups in the thermal behavior of CuO.

关键词： thermal diffusivity CuO thermal lens morphology hydroxyl group

In-situ fabrication of Al(Zn)-Al_2O_3 graded composite using the aluminothermic reaction during hot pressing

在线全文

学校读者我要写书评

暂无评论

International Journal of minerals,metallurgy and materials 2018年第7期25卷 832-839页

作者： s.m.a.haghi s.a.sajjadi a.babakhani Department of materials science and Engineering Engineering facultyFerdowsi University of MashhadMashhadIra

In INs study, the fabrication of multilayer AI（Zn）-A1203 with different volume fractions of A1203 was investigated. A1 and ZnO powders were milled by a plaaetaxy ball mill, after which five-layer functionally graded samples were produced flarough hot pressing at 580~C and 90 mPa pressure for 30 min. Formation of reinforcing A1203 particles occurred in the aluminum matrix via the aluminolkermic reaction. Determination of the ignition temperature of the aluminolkennic reaction was accomplished using differential lkermal and lkermo- gravimelric amlyses. scaaming electron microscopy, energy dispersive spectroscopy, and X-ray diffractometery amlyses were utilized to characterize the specimens. The lkermal amlysis results showed that the ignition temperatures for the aluminolkennic reaction of layers with the highest and lowest ZnO contents were 667 and 670~C, respectively. microslxuctural observation and chemical amlysis confirmed the fa- brication of AI（Zn）-A1203 functionally graded materials composites with precipitation of additional Zn in the matrix. moreover, nearly dense functionally graded samples demonstrated minimum and maximum hacdness values of HV 75 and HV 130, respectively.

关键词： metal-matrix composites functionally graded composites fllermogravimet^ic analysis powder processing sintering

Nonlinear continuous bi-inductance electrical line with dissipative elements:Dynamics of the low frequency modulated waves

在线全文

学校读者我要写书评

暂无评论

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

Corrosion Behaviour of Nickel in Chloroacetic Acids and its Inhibition

在线全文

学校读者我要写书评

暂无评论

Journal of materials science & Technology 2004年第1期20卷 121-125页

作者： s.m.Rashwan A.Emam s.m.Abd El-Wahab m.m.mohamed Chemistry Department Faculty of Science Suez Canal University Ismailia EgyptChemistry Department Faculty of Science Suez Canal University Ismailia EgyptChemistry Department Faculty of Science Ain Shams University Cairo EgyptChemistry Department Faculty of Science Suez Canal University Ismailia Egypt

Anodic dissolution behaviour of Ni in mono-, di- and trichloroacetic acids has been investigated by measuring current densities of Ni electrode (versus sCE) at different potentials. Effects of acid concentration, pH, scan rate and additive inhibitor on the potential were studied and they revealed that there is a considerable shift of potential. Potentiodynamic polarization measurements show that the corrosion rate of Ni in chloroacetic acid solutions increases by increasing the previous factors. However, by adding inhibitor, it decreases.

关键词： Corrosion Nickel Chloroacetic acids Inhibition

Effect of inertial acoustic cavitation on antibiotic efficacy in biofilms

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2021年第10期42卷 1397-1422页

作者： m.GHAsEmI s.sIVALOGANATHAN Department of Applied mathematics University WaterlooWaterloo N2L 3G1Canada

Bacterial biofilms can lead to chronic infections,increase tolerance to antibiotics and disinfectants,resistance to phagocytosis,and other components of the body’s immune *** formation is implicated in the persistence of staphylococcal infections and chronic Pseudomonas aeruginosa lung infections in cystic fibrosis(CF)patients(which can result from biofilm-growing mucoid strains).Conventional treatments utilize aggressive antibiotic prophylaxis/therapy to prevent/eliminate biofilms,followed by chronic suppressive ***,the use of enzymes to dissolve the biofilm matrix was investigated,in addition to quorum sensing inhibitors to increase biofilm susceptibility to ***,we propose a novel strategy,utilizing ultrasound-induced inertial cavitation,to increase antibiotic *** wall shear stress at the biofilm interface is calculated,and viscoplastic constitutive equations are used to examine the biofilm response to the mechanical *** simulations suggest that the maximum biofilm detachment occurs at high pressure/low frequency,and the mechanical disruption can affect the biochemical processes inside the biofilm resulting in vulnerability to antibiotics.

关键词： biofilm mechanical disruption mathematical model acoustic cavitation bubble collapse antibiotic

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

在线全文

学校读者我要写书评

暂无评论

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

Comprehensive investigation of stress intensity factors in rotating disks containing three-dimensional semi-elliptical cracks

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2017年第11期38卷 1565-1578页

作者： m.FAKOOR s.m.N.GHOREIsHI Faculty of New sciences and Technologies University of Tehran Tehran 14395-1561 Iran

Initiation and propagation of cracks in rotating disks may cause catastrophic failures. Therefore, determination of fracture parameters under different working con- ditions is an essential issue. In this paper, a comprehensive study of stress intensity factors （sIFs） in rotating disks containing three-dimensional （3D） semi-elliptical cracks subjected to different working conditions is carried out. The effects of mechanical prop- erties, rotational velocity, and orientation of cracks on sIFs in rotating disks under cen- trifugal loading are investigated. Also, the effects of using composite patches to reduce sIFs in rotating disks are studied. The effects of patching design variables such as mechanical properties, thickness, and ply angle are investigated separately. The modeling and analytical procedure are verified in comparison with previously reported results in the literature.

关键词： stress intensity factor (sIF) semi-elliptical crack rotating disk finite ele-ment analysis (FEA)