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A Note on the Anti-glitch of Magnetar SGR 1935+2154

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Research in Astronomy and Astrophysics 2023年第2期23卷 172-176页

作者： h.Tong School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China

The magnetar SGR 1935+2154 is reported to have an anti-glitch,accompanied by fast radio bursts,and transient pulsed radio *** the wind braking model,this triplet event tells people that(1) SGR 1935+2154 does not have a strong particle wind and can be approximated by magnetic dipole braking in the persistent state;(2) its antiglitch is due to an enhanced particle wind,similar to the first anti-glitch in magnetars;(3) its transient pulsed radio emission may be due to a decreasing emission beam during the outburst;(4) the enhanced particle acceleration potential and pulsar death line may not be the dominate factor.

关键词： stars magnetars-(stars:)pulsars general-(stars:)pulsars individual(SGR 1935+2154)

Design of logic process based low-power 512-bit EEPROM for UhF RFID tag chip

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Journal of Central South University 2010年第5期17卷 1011-1020页

作者：金丽妍 LEE J h KIM Y h Department of Electronic Engineering Changwon National University

A 512-bit EEPROM IP was designed by using just logic process based *** limit the voltages of the devices within 5.5 V,EEPROM core circuits,control gate(CG) and tunnel gate(TG) driving circuits,DC-DC converters:positive pumping voltage(VPP=4.75 V) ,negative pumping voltage(VNN=4.75 V) ,and VNNL(=VNN/2) generation circuit were *** addition,switching powers CG high voltage(CG_hV) ,CG low voltage(CG_LV) ,TG high voltage(TG_hV) ,TG low voltage(TG_LV) ,VNNL_CG and VNNL_TG switching circuit were supplied for the CG and TG driving ***,a sequential pumping scheme and a new ring oscillator with a dual oscillation period were *** reduce a power consumption of EEPROM in the write mode,the reference voltages VREF_VPP for VPP and VREE_VNN for VNN were used by dividing VDD(1.2 V) supply voltage supplied from the analog block in stead of removing the reference voltage generators.A voltage level detector using a capacitive divider as a low-power DC-DC converter design technique was *** result shows that the power dissipation is 0.34μW in the read mode,13.76μW in the program mode,and 13.66μW in the erase mode.

关键词： electrically erasable programmable read-only memory (EEPROM) logic process DC-DC converter ring oscillator sequential pumping scheme dual oscillation period radio frequency identification (RFID)

Mechanism of fracture in macro- and micro-scales in hollow centre cracked disc specimen

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Journal of Central South University 2015年第11期22卷 4426-4433页

作者： M.Eftekhari A.Baghbanan h.hashemolhosseini h.Amrollahi Department of Mining Engineering Isfahan University of Technology (IUT)

The hollow centre cracked disc(hCCD) specimen is one of the suggested alternative methods for determining the fracture toughness of rock. This work aims to investigate the fracture mechanism in hCCD in macro- and micro-scales using numerical methods, extended finite element method(X-FEM) and particle flow code(PFC) modeling, respectively. In the X-FEM, heaviside and near-tip enrichment functions are employed to consider the presence of the crack in the model. In PFC modeling the movement and interaction of stressed assemblies of rigid spherical particles are modeled using the distinct element method(DEM). A numerical code called MEX-FEM based on XFEM has been developed to simulate the problems involving crack. The models of pure modes I and Ⅱ in macro-scale are simulated in micro-scale. The results show that dimensionless stress intensity factors(YI, YⅡ) for pure modes I and Ⅱ increase by increasing the crack length ratio. The angle at which the pure mode Ⅱ occurs decreases by increasing the crack length ratio. In mixed mode I-Ⅱ, The value of YI decreases by increasing the crack angle, while the value of YⅡ increases to a given crack angle and then it decreases. Moreover, the fracture in micro-scale, unlike the macro-scale, includes a combination of different modes of fracturing.

关键词： hollow centre cracked disc(hCCD) extended finite e

Combustion synthesis, characterization and luminescence properties of barium aluminate phosphor

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Journal of Rare Earths 2014年第9期32卷 806-811页

作者： A.h. Wako F.B Dejene h.C Swart Department of Physics University of the Free State (Qwaqwa Campus) Department of Physics University of the Free State

The blue-green emitting Eu2＋ and Nd3＋ doped polycrystalline barium aluminate （BaAI204：Eu2＋,Nd3＋） phosphor, was prepared by a solution-combustion method at 500 ℃without a post-annealing process. The characteristic variation in the structural and luminescence properties of the as-prepared samples was evaluated with regards to a change in the Ba/A1 molar ratio from 0.1：1 to 1.4：1. The morphologies and the phase structures of the products were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, while the optical properties were investigated using ultra-violet （UV） and photoluminescence （PL） spectroscopy, respectively. The XRD and TEM results revealed that the average crystallite size of the BaAl2O4：Eu2＋,Nd3＋ phosphor was about 70 urn. The broad-band UV-excited luminescence of the phosphors was observed at 2max=500 um due to transitions from the 4f^65d1 to the 4f7 configuration of the Eu2＋ ion. The PL results indicated that the main peaks in the emission and excitation spectrum of phosphor particles slightly shifted to the short wavelength due to the changes in the crystal field due to the structure changes caused by the variation in the quantity of the Ba ions in the host lattice.

关键词： BaAl2O4:Eu2+,Nd3+ persistence luminescence Eu2+ and Nd3+ doping rare earths

Numerical Analysis of MhD Accelerator with Non-Equilibrium Air Plasma

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Plasma Science and Technology 2012年第12期14卷 1110-1115页

作者： M.ANWARI h.h.QAZI SUKARSAN N.hARADA Electrical Engineering Department Umm Al-Qura University Faculty of Electrical Engineering Universiti Teknologi Malaysia Faculty of Electrical Engineering Universitas Islam "45" Bekasi Department of Electrical Engineering Nagaoka University of Technology

Magnetohydrodynamic （MhD） accelerator is proposed as a next generation propulsion system. It can be used to increase the performance of a propulsion system. The objective of this study is to investigate the performance of MhD accelerator using non-equilibrium air plasma as working gas. In this study, the fundamental performance of MhD accelerator such as flow performance and electrical performance is evaluated at different levels of applied magnetic field using I-D numerical simulation. The numerical simulation is developed based on a set of differential equations with MhD approximation. To solve this set of differential equations the MacCormack scheme is used. A specified channel designed and developed at NASA Marshall Space Flight Centre is used in the numerical simulation. The composition of the simulated air plasma consists of seven species, namely, N2, N, O2, O, NO, NO＋, and e-. The performance of the non-equilibrium MhD accelerator is also compared with the equilibrium MhD accelerator.

关键词： MhD accelerator Faraday type connection non-equilibrium air plasma

Application of high silica zeolite ZSM-5 in a hybrid treatment process based on sequential adsorption and ozonation for VOCs elimination

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Journal of Environmental Sciences 2016年第3期28卷 59-68页

作者： hicham Zaitan Marie hélène Manero héctor Valdés Laboratoire de Chirmie de la Matiere Condensee(LCMC) Faculte des Sciences et TechniquesUniversite Sidi Mohamed Ben AbdellahB.P.2202FesMaroc Universite de Toulouse INPTUPSLaboratoire de Genie Chimique4Allee Emile MonsoF-31030 ToulouseFrance CNRS Laboratoire de Genie ChimiqueF-31030 ToulouseFrance Laboratorio de Tecnologias Limpias(F.Ingenieria) Universidad Catolica de la Santisima ConcepcionAlonso de Ribera 2850ConcepcionChile

In this study,a hydrophobic synthetic zeolite,namely ZSM-5 is chosen as an adsorbent/catalyst for toluene *** results showed that toluene adsorption onto ZSM-5 was favourable,following a Langmuir adsorption isotherm ***-5 zeolite was regenerated using gaseous ozone at low *** toluene was oxidised,releasing mainly CO_2 and h_*** of oxidation by-products such as acetic acid and acetaldehyde were formed and remained adsorbed after the oxidativate regeneration with *** four successive cycles of adsorption/ozonation,the adsorption efficiency was not affected（92%-99%）.These results showed that volatile organic compound（VOC）removal by adsorption onto ZSM-5 zeolite followed by ozone regeneration could be used as a promising hybrid process for the control of VOC emissions in terms of efficiency.

关键词： Adsorption Ozone Toluene VOCs Zeolite

Influence of Zn^(2+)or Cu^(2+) on Reduction and Recalcination Behavior of Fe_2TiO_5

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Journal of Materials Science & Technology 2007年第5期23卷 697-702页

作者： M.Bahgat M.h.Khedr h.S.Abdelmaksoud CMRDI P.O.Box 87-HelwanCairoEgypt Chemistry Department Faculty of ScienceBenisuef UniversityEgypt

Fe2O3, TiO2, CuO and ZnO powders were mixed according to the formula of （1-x）TiO2 xCuO-Fe2O3 or （1-x）TiO2 xZnO-Fe2O3 （x=0, 0.2 0.4, 0.6, 0.8, 1）, and well ball-milled with h2O for 3 h to ensure homogeneity of the powdered solids, then fired at 1200℃ for 4 h. The fired samples were reduced at 500℃ with hydrogen gas. The reduced samples were subjected to recalcination at 500℃ in CO2 atmosphere. Both of fired, reduced and calcined samples were characterized by X-ray diffraction, vibrating sample magnetometry, reflected light microscopy and scanning electron microscopy. Different phases were formed after firing of Cu^＋2 or Zn^2＋ substituted Fe2TiO5. Magnetization （Bs） of the formed phases after firing are very low corresponding to diluted magnetic semiconductors （DMS） and increases with increasing the substituted cations （Cu^＋2 or Zn^2＋）. The reduction of the fired samples enhanced the Bs values whereas the reducibility increases with increasing the Cu^＋2 or Zn^2＋ content. Samples show different tendency toward CO2 decomposition which is very important for environmental minimization for CO2.

关键词： Nanosized ferrite Titanate Reduction Magnetic properties Reduction-recalcin-ation CO2 decomposition

Exact solution for the unsteady flow of a semi-infinite micropolar fluid

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Acta Mechanica Sinica 2011年第3期27卷 354-359页

作者： h.h. Sherief M.S. Faltas E.A. Ashmawy Department of Mathematics Faculty of ScienceAlexandria University

The unsteady motion of an incompressible micropolar fluid filling a half-space bounded by a horizontal infinite plate that started to move suddenly is considered. Laplace transform techniques are used. The solution in the Laplace transform domain is obtained by using a direct approach. The inverse Laplace transforms are obtained in an exact manner using the complex inversion formula of the transform together with contour integration techniques. The solution in the case of classical viscous fluids is recovered as a special case of this work when the micropolarity coecient is assumed to be zero. Numerical computations are carried out and represented graphically.

关键词： Unsteady motion . Laplace transform . Microp-olar fluid

Fundamental solutions for axi-symmetric translational motionof a microstretch fluid

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Acta Mechanica Sinica 2012年第3期28卷 605-611页

作者： h.h.Sherief M.S.Faltas E.A.Ashmawy Department of Mathematics Faculty of ScienceAlexandria University

The fundamental solution for the axi-symmetric translational motion of a microstretch fluid due to a concen- trated point body force is obtained. A general formula for the drag force exerted by the fluid on an axi-symmetric rigid par- ticle translating in it is then deduced. As an application to the obtained drag formula, this paper has discussed the problem of creeping translational motion of a rigid sphere in a mi- crostretch fluid. The slip boundary condition on the surface of the spherical particle is applied. The drag force and the other physical quantities are obtained and represented graph- ically for various values of the micropolarity and slip param- eters.

关键词： Drag force Fundamental solution Mi-crostretch fluid Slip condition