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Method for converting in-situ gamma ray spectra of a portable Ge detector to an incident photon flux energy distribution based on Monte Carlo simulation

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Nuclear Science and Techniques 2008年第6期19卷 358-364页

作者： Boubaker ASKRI adel TRABELSI Brahim BACCARI Unité de Physique Nucléaire et des Hautes énergies Faculté des Sciences de Tunis2092 TunisTunisia Centre National de Sciences et de Technologies Nucléaires Sidi ThabetTunisia

A matrix stripping method for the conversion of in-situ gamma ray spectrum, obtained with portable Ge detector, to photon flux energy distribution is proposed. The detector response is fully described by its stripping matrix and full absorption efficiency curve. A charge collection efficiency function is introduced in the simulation to take into account the existence of a transition zone of increasing charge collection after the inactive Ge layer. Good agreement is obtained between simulated and experimental full absorption efficiencies. The characteristic stripping matrix is determined by Monte Carlo simulation for different incident photon energies using the Geant4 toolkit system. The photon flux energy distribution is deduced by stripping the measured spectrum of the partial absorption and cosmic ray events and then applying the full absorption efficiency curve. The stripping method is applied to a measured in-situ spectrum. The value of the absorbed dose rate in air deduced from the corresponding flux energy distribution agrees well with the value measured directly in-situ.

关键词：蒙特卡罗模拟锗探测器伽马射线拆模仿式

Predictive control of a chaotic permanent magnet synchronous generator in a wind turbine system

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Chinese Physics B 2015年第1期24卷 177-183页

作者： Manal Messadi adel Mellit Karim Kemih Malek Ghanes LRE Laboratory Jijel University BP 98 ouled Aissa Jijel Algeria L2EI laboratory Jijel University BP 98 ouled Aissa Jijel Algeria ECS-ENSEA cergy-pontoise France 6 avenue du Ponceau 95014 Cergy-Pontoise Cedex

This paper investigates how to address the chaos problem in a permanent magnet synchronous generator（PMSG） in a wind turbine system. Predictive control approach is proposed to suppress chaotic behavior and make operating stable;the advantage of this method is that it can only be applied to one state of the wind turbine system. The use of the genetic algorithms to estimate the optimal parameter values of the wind turbine leads to maximization of the power ***, some simulation results are included to visualize the effectiveness and robustness of the proposed method.

关键词： permanent magnet synchronous generator chaotic system genetic algorithm predictive control

Digital compass for multi-user beam access in mmWave cellular networks

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数字通信与网络:英文版 2023年第4期9卷 879-886页

作者： adel Aldalbahi Nazli Siasi Asim Mazin Mohammed A.Jasim Department of Electrical Engineering King Faisal UniversityAl-Ahsa34221Saudi Arabia School of Computing DePaul UniversityChicagoIL60604USA Department of Electrical Engineering University of South FloridaTampaFL33620USA School of Engineering and Technology University of WashingtonTacomaWA98402USA

Beamforming in stand-alone Millimeter-Wave(mmWave)communications results in prolonged access times and latencies due to the increased number of measurements required to determine the optimal beam directions at the Mobile Station(MS)and Base Station(BS),returning the highest received signal ***,dynamic and fast access schemes that meet the Third-Generation Partnership Project(3GPP)specifications are required ***,in this paper,a novel initial access scheme is proposed for multiple MS users by leveraging for the first time a digital compass in the access ***,when a new MS joins the footprint of a BS,it probes the channel for beacon signaling about the BS direction,i.e.,broadcasted by a neighboring MS that completed beam association at previous time ***,a digital compass is utilized to adjust the coordinates of the BS according to the location of the new *** proposed scheme is applied for a single and multi-user settings at various broadcasting *** includes a single associated MS user that broadcasts information to a single incoming MS user,a single user that broadcasts signals to multiple incoming users,or all multiple associated users broadcast to multiple incoming ***,the proposed schemes yield in notable efficiency in terms of the computational complexity,access times,power and energy consumption as compared to existing access ***,high success rates are achieved at the detriment of relatively higher cost.

关键词： Millimeter wave Initial beam access Electronic compass Beamforming Access times Energy consumption

A two-dimensional lithospheric magnetic anomaly field model of Egypt using the measurements from Swarm satellites

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Geodesy and Geodynamics 2021年第3期12卷 229-238页

作者： adel Fathy Essam Ghamry Physics Department Faculty of ScienceFayoum UniversityEgypt National Research Institute of Astronomy and Geophysics 11421HelwanCairoEgypt

We use magnetic field data observed by the Swarm mission from 2014 to 2020 to construct,for the first time,a two-dimensional(2 D)lithospheric magnetic anomaly model of Egypt and its surrounding *** data during quiet geomagnetic conditions has been expanded in terms of the Legendre polynomial in harmonic terms N=*** damped least square method has been used to estimate the model coefficients based on the lithospheric magnetic *** data at two different altitudes(438-448 km and 503-511 km)were compared with the CHAOS *** exhibit that the 2 D model is superior to the CHAOS model in the capability of extracting more information about small-scale crustal anomaly *** low altitudes(438-448 km),the strength of the anomaly field increases,but the noise of the external fields has greatly reduced at high altitudes(503-511 km).Besides,the magnetic anomaly field at low altitudes has illuminated short-scale anomalies that didn’t appear at high *** the total and vertical magnetic anomaly vectors showed their ability to reveal tectonic structures compared with Moho depth map and the geological maps.

关键词： Damped inverse theory Swarm satellites Lithospheric magnetic anomaly field Legendre polynomial Egypt

Carbon nanotube-based nanoelectromechanical resonatoras mass biosensor

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Chinese Physics B 2020年第7期29卷 583-587页

作者： Ahmed MElseddawy adel HPhillips Ahmed S Bayoumi Faculty of Graduate Studies University of WindsorWindsorOntarioCanada Faculty of Engineering Ain-Shams UniversityCairoEgypt Faculty of Engineering Kafr-Elsheikh UnversityKafr-ElsheikhEgypt

The use of single walled carbon nanotube-based nanoelectromechanical system(NEMS)resonator to sense the biomolecules'mass is investigated under the influence of an external ac-field.A single walled carbon nanotube(SWCNT)cantilever has been proposed and studied if the mass is attached at the tip or various intermediate *** shift of the resonant frequency and the quality factor have been investigated and show high sensitivity to the attached mass of biomolecule and its *** proposed SWCNT-based NEMS resonator is a good candidate for sensing and tracing biomolecules'mass as concentration of acetone in human exhale,resulting in a painless,correct,and simple diabetics'diagnosis.

关键词： single walled carbon nanotube nanoelectromechanical system resonator ac-field biomolecule

LES of rotating film-cooling performance in a 1-1/2 turbine stage

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Propulsion and Power Research 2019年第2期8卷 85-107页

作者： Nabeel Al-Zurfi adel Nasser Mechanical Engineering Department Faculty of EngineeringUniversity of KufaNajafIraq School of Mechanical Aerospace and Civil EngineeringThe University of ManchesterManchesterM139PLUK

The large eddy simulation method was employed to investigate the film-cooling performance in a low-speed rotor blade of a 1-1/2 turbine *** rotor blade height and axial chord length were 99 mm and 124.3 mm,*** rows of film holes were placed on the rotor blade surface,one each on the pressure and suction *** row had three cylindrical film holes with a diameter of 4 mm and a tangential injection angle of 28°on the pressure side and 361 on the suction *** Reynolds number was fixed at Re=1.92×10^(5)and the coolant-to-mainstream density ratio(DR)was about *** were carried out for three different rotating speeds of 1800,2100,and 2400 rpm with the blowing ratio(BR)varying from 0.3 to *** commercial CFD code STAR-CCM+was used to run the simulations using the WALE subgrid-scale model for modelling the *** results show that on the pressure side,the film coverage and filmcooling effectiveness decrease with increasing rotation number(Ro)and increase with increasing blowing ratio(BR).A higher Ro and lower BR result in a stronger film *** film injection with higher BR produces better film *** film deflects centrifugally where the deflection becomes greater with increasing *** the suction side,the film coverage and film-cooling effectiveness increase with increasing either Ro or BR and a centripetal deflection of the film is *** deflection of the film path could be amplified by either increasing the Ro at a constant BR or decreasing the BR at a constant *** the rotation weakens the film deflection towards the hub on the suction ***,it was found that both rotation number and blowing ratio play significant roles in determining the film-cooling effectiveness distributions of the rotor blade surface.

关键词： Rotor blade Large eddy simulation Film-cooling effectiveness Turbulence Rotation Subgrid-scale

Effect of sintering temperature on microstructure and electrical properties of Sr_(1-x)(Na_(0.5)Bi_(0.5))_(x)Bi_(2)Nb_(2)O_(9) solid solutions

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Journal of Advanced Ceramics 2014年第1期3卷 17-30页

作者： Hana NACEUR adel MEGRICHE Mohamed EL MAAOUI Laboratory of Applied Mineral Chemistry Department of ChemistryFaculty of SciencesUniversity Tunis ElManarCampus 2092TunisTunisia

In this study,we investigated the effect of sintering temperature on densification,grain size,conductivity and dielectric properties of Sr_(1-x)(Na_(0.5)Bi_(0.5))_(x)Bi_(2)Nb_(2)O_(9) ceramics,prepared by hydrothermal *** were sintered at different *** increased with sintering temperature,reaching up to 96%at 800℃.A grain growth was observed with increasing sintering *** spectroscopy analyses of the sintered samples at various temperatures were *** in dielectric constant and in Curie temperature with sintering was *** conductivity and activation energy were calculated and attributed to the microstructural factors.

关键词： ceramics sintering light scattering dielectric properties

Corneal collagen crosslinking in keratoconus and other eye disease

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International Journal of Ophthalmology(English edition) 2015年第2期8卷 407-418页

作者： adel Alhayek Pei-Rong Lu Department of Ophthalmology the First Affiliated Hospital of Soochow University

Keratoconus is a condition characterized by biomechanical instability of the cornea, presenting in a progressive, asymmetric and bilateral way. Corneal collagen crosslinking(CXL) with riboflavin and Ultraviolet-A(UVA) is a new technique of corneal tissue strengthening that combines the use of riboflavin as a photo sensitizer and UVA irradiation. Studies showed that CXL was effective in halting the progression of keratoconus over a period of up to four years. The published studies also revealed a reduction of max K readings by more than 2 D, while the postoperative spherical equivalent(SEQ) was reduced by an average of more than 1 D and refractive cylinder decreased by about1 D. The major indication for the use of CXL is to inhibit the progression of corneal ecstasies, such as keratoconus and pellucid marginal degeneration. CXL may also be effective in the treatment and prophylaxis of iatrogenic keratectasia, resulting from excessively aggressive photo ablation. This treatment has been used to treat infectious corneal ulcers with apparent favorable results. Most recent studies demonstrate the beneficial impact of CXL for iatrogenic ecstasies, pellucid marginal degeneration, infectious keratitis, bullous keratopathy and ulcerative keratitis. Several long-term and short-term complications of CXL have been studied and documented. The possibility of a secondary infection after the procedure exists because the patient is subject to epithelial debridement and the application of a soft contact lens. Formation of temporary corneal haze,permanent scars, endothelial damage, treatment failure,sterile infiltrates, bullous keratopathy and herpes reactivation are the other reported complications of this procedure.

关键词： keratoconus collagen corneal cross-linking ultraviolet radiation and riboflavin

Gas condensate reservoirs: Characterization and calculation of dew-point pressure

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Petroleum Exploration and Development 2020年第5期47卷 1091-1102页

作者： ALAROUJ Mutlaq ALOMAIR Osamah ELSHARKAWY adel Petroleum Engineering Department College of Engineering&PetroleumKuwait UniversityPO Box 5956Safat 13060Kuwait

A large data bank of more than 700 gas-condensate samples collected from literature and experiments was *** this basis,empirical correlations and equations of state commonly used to calculate dew-point pressure(DPP)were evaluated.A new model for estimating DPP was *** the empirical correlations and the Peng-Robinson state equation were compared,and sensitivity of parameters was *** current standards used to identify gas condensate were evaluated and found to be not accurate *** Peng-Robinson state equation has no unique solution and is affected by multiple factors such as the characterization of C7+components and the splitting *** Nemeth-Kennedy correlation has the highest accuracy when applied to the data bank established in this study,followed by Elsharkawy correlation and Godwin *** Shokir correlation cannot be used for samples without C7+components,it is therefore the lowest in *** newly proposed model has an average absolute error,root mean square error and coefficient of determination of 7.5%,588,and 0.87,respectively,and is better than the above four correlations *** proposed model proved to be more accurate and valid when compared to experimental results and simulation with the Peng-Robinson state equation.

关键词： gas condensate reservoir dew-point pressure empirical relation equation of state