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Vertical marginal gap &retention of ceramic full coverage &inlay retained ceramic fixed partial dentures

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Open Journal of Stomatology 2011年第4期1卷 140-149页

作者： cherif mohsen Faculty of Dentistry Minia University

Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were construc- ted and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-pro- ximal inlay + proximal box), tub-shaped (occluso-pro- ximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shap- ed inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was signifi-cant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant dif-ference than the other two inlay retained FPDs de-signs. Conclusions: There was no significant differ- ence between full coverage FPDs, tub-shaped & pro- ximal box shaped inlay retained FPDs as regard ver- tical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrep- ancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical mar- ginal discrepancies were in the range of clinical ac- ceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs de- signs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay re- tained FPDs designs. There was no difference as re- gard retentive strengths between tub-shaped & pro- ximal box shaped inlay retained FPDs.

关键词： Inlay Retained FPDs Full Coverage FPDs Retentive Strengths Vertical Marginal Discrepancies

Corrosion effect on the flexural strength & micro-hardness of ips e-max ceramics

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Vertical marginal gap & retention of ceramic full coverage & inlay retained ceramic fixed partial dentures

Open Journal of Stomatology 2011年第2期

作者： cherif mohsen

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New results for a Lasota-Wazewska model

Open Journal of Stomatology 2011年第4期

作者： cherif mohsen

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International Journal of Biomathematics 2019年第2期12卷 143-162页

作者： Farouk cherif mohsen Miraoui MaPSFA LR11ES35ISSATUniversity of Sousse4002 SousseTunisia IPEIK University of Kairouan3100 KairouanTunisia LR11ES53Faculty of Sciences of Sfax University of SfaxTunisia

In nature there is no phenomenon that is purely periodic,and this gives the idea to consider the measure pseudo almost periodic *** this paper,by employing a suitable fixed point theorem,the proper ties of the measure pseudo almost periodic functions and differential inequality,we investigate the existence and uniqueness of the measure pseudo almost periodic solutions for some models of Lasota-Wazewska equation with measure pseudo almost periodic coefficients and mixed *** suppose that the linear part has almost periodic and the nonlinear part is assumed to be measure pseudo almost ***,the global attractivity and the exponential stability of the measure pseudo almost periodic solutions are also considered for the *** application,an illustrative numerical example is given to demonstrate the effectiveness of the obtained results.

关键词： Lasota Wazewska model measure pseudo almost periodic function fixed point theorem

Imaging of target with complicated motion using ISAR system based on IPHAF-TVA

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Chinese Journal of Aeronautics 2021年第2期34卷 252-264页

作者： Abdelkader ALI cherif Yong WANG Algerian Space Agency Satellite Development CenterOran 31000Algeria Research Institute of Electronic Engineering Technology Harbin Institute of TechnologyHarbin 150001China

The technique of imaging a target with a complicated motion using an Inverse Synthetic Aperture Radar(ISAR) system is an effective tool in the field of radar signal processing. After the translational compensation, the received signal reflected from the target can take the form of a multi-component Polynomial Phase Signal(m-PPS), and the high quality ISAR image can be provided via the combination between the estimated parameters of the m-PPS and the Range Instantaneous-Doppler technique(RID). For a target with a high maneuvrability, the occurrence of scatterers Migration Through Resolution Cell(MTRC), caused by the rotational movement could be appearing. That is why the variation in the amplitude of the echo during the time of observation cannot be neglected. The purpose of this study is the parameters estimation of the m-PPS signal with order three in the case of the Time Varying Amplitude(TVA). The Improved-version of the Product High-order Ambiguity Function(IPHAF) with TVA is proposed to improve the quality of the ISAR image compared with traditional techniques based on a constant amplitude;the experimental outcomes confirm that the new IPHAF-TVA method presented in this study is an effective technique to make the ISAR image very clear.

关键词： Inverse Synthetic Aperture Radar(ISAR) Maneuvering target Multi-component Polynomial Phase Signal(m-PPS) Product High-Order Ambiguity Function(IPHAF) Time Varying Amplitude(TVA)

Optimum allocation of FACTS devices in Fars Regional Electric Network using genetic algorithm based goal attainment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 478-487页

作者： mohsen GITIZADEH mohsen KALANTAR Center of Excellence for Power System Automation and Operation Department of Electrical Engineering Iran University of Science and TechnologyTehran 16844 Iran

This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensators (TCSCs) and static var compensators (SVCs) are the utilized FACTS devices. Our objectives are active power loss reduction, newly introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, were considered in the optimum allocation. A goal attainment method based on the genetic algorithm (GA) was used to approach the global optimum. The estimated annual load profile was utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. Fars Regional Electric Network was selected as a practical system to validate the performance and effectiveness of the proposed method. The entire investment of the FACTS devices was paid off and an additional 2.4% savings was made. The cost reduction of peak point power generation implies that power plant expansion can be postponed.

关键词： Flexible alternating current transmission system (FACTS) devices allocation Multi-objective optimization Geneticalgorithm (GA) Goal attainment

Effects of porous material on transient natural convection heat transfer of nano-fluids inside a triangular chamber

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1203-1213页

作者： mohsen Izadi Mechanical Engineering Department Faculty of EngineeringLorestan UniversityKhorramabadIran

This study numerically investigates the impact of porous materials,nano-particle types,and their concentrations on transient natural convection heat transfer of nano-fluid inside a porous chamber with a triangular *** governing equations of the two-phase mixture model are separated on the computational domain and solved using the Finite Volume Method,taking into account the Darcy–Brinkman model for porous *** was observed that convection heat transfer inside the triangular chamber consists of three stages named initial,transient,and *** features of each step are provided in *** results suggested that the use of a hybrid nano-fluid(water/aluminum oxide-cooper)inside a porous glass material and an increase in volume fraction of nano-particles have adverse effects on heat transfer *** contrast,as the nano-particle volume fraction of the single nano-fluid(water/aluminum oxide)inside the chamber increased,convection heat transfer rate *** the same time,it was observed that the use of both nano-fluids(single and hybrid)in the porous environment of the aluminum foam could improve convection.

关键词： Transient natural convection Mixture model Darcy-Brinlanan model Rayleigh-Benard instability Triangular chamber

Orbital electronic heat capacity of hydrogenated monolayer and bilayer graphene

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Chinese Physics B 2017年第2期26卷 375-381页

作者： mohsen Yarmohammadi Young Researchers and Elite Club Kermanshah Branch Islamic Azad University Kermanshah Ira

The tight-binding Harrison model and Green＇s function approach have been utilized in order to investigate the contribution of hybridized orbitals in the electronic density of states（DOS） and electronic heat capacity（EHC） for four hydrogenated structures, including monolayer chair-like, table-like, bilayer AA- and finally AB-stacked graphene. After hydrogenation, monolayer graphene and bilayer graphene are behave as semiconducting systems owning a wide direct band gap and this means that all orbitals have several states around the Fermi level. The energy gap in DOS and Schottky anomaly in EHC curves of these structures are compared together illustrating the maximum and minimum band gaps are appear for monolayer chair-like and bilayer AA-stacked graphane, respectively. In spite of these, our findings show that the maximum and minimum values of Schottky anomaly appear for hydrogenated bilayer AA-stacked and monolayer table-like configurations, respectively.

关键词： hydrogenated monolayer and bilayer graphene Harrison model electronic heat capacity density of states Green's function

Adaptive Output Feedback Regulation for a Class of Uncertain Feedforward Time-Delay Nonlinear Systems

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Journal of Systems Science & Complexity 2020年第3期33卷 604-621页

作者： BELFEKI mohsen University of Sfax IPEISRoute Menzel ChakerKM 0.5B.P.1172Sfax 3018Tunisia Department of mathematics Alkurmah University collegeTaif UniversitySaudi Arabia

This paper addresses the global output feedback regulation problem for a class of uncertain feedforward time-delay nonlinear *** to the previous works,the nonlinear functions in the class of systems under consideration are dominated by an input-output function multiplied by an unknown parameter and linear unmeasured *** using only one dynamic gain and an appropriate Lyapunov-Krasovskii functionals,it is shown that the closed-loop system is globally asymptotically ***,a numerical example is provided to illustrate the effectiveness of the proposed design scheme.

关键词： Adaptive regulation dynamic gain output feedback uncertain feedforward time-delay systems