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ELECTROSPINNING OF CYCLODEXTRIN FUNCTIONALIZED CHITOSAN/PVA NANOFIBERS AS A DRUG DELIVERY SYSTEM

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Chinese Journal of Polymer Science 2013年第10期31卷 1343-1351页

作者： Maryam Bazhban mahdi Nouri Javad Mokhtari Department of Textile Engineering Faculty of Engineering University of Guilan

A new type ofnanofibrous structure from chitosan bearing carboxymethyl-β-cyclodextrin （CS-g-β-CD） as a novel drug delivery system was synthesized by grafting carboxymethyl-β-cyclodextrin （CM β-CD） onto chitosan （CS） in the presence of water soluble 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide （EDC） as the condensing agent and N-hydroxysuccinimide （NHS）. Defect free mats containing CS-g-β-CD have been fabricated using electrospirming of an aqueous solution of poly（vinyl alcohol）（PVA）/CS-g-β-CD blends. The morphology and diameter of the electrospun nanofibers were examined by scanning electron microscopy （SEM）. The average fiber diameter was in the range of 130-210 run. SEM images showed that the morphology and diameter of the nanofibers were mainly affected by weight ratio of the blend at constant applied voltage. The results revealed that increasing CS-g-β-CD content in the blends decreases the average fiber diameter. It was observed that the PVA/CS-g-β-CD nanofibrous mat provided a slower release of the entrapped drug in compare to PVA/CS nanofibrous mat.

关键词： Chitosan βcyclodextrin Nanofibers Drug delivery.

Improved rate-distortion optimized video coding using non-integer bit estimation and multiple Lambda search

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Frontiers of Computer Science 2016年第1期10卷 157-166页

作者： Sio Kei IM Mohammad mahdi GHANDI MPI-QMUL Information Systems Research Centre Macao Polytechnic Institute Macao China Department of Electronic Systems Engineering University of Essex Colchestey CO4 3SQ UK

Many modern video encoders use the Lagrangian rate-distortion optimization （RDO） algorithm for mode deci- sions during the compression procedure. For each encoding stage, this approach involves minimizing a cost, which is a function of rate, distortion and a multiplier called Lambda. This paper proposes to improve the RDO process by applying two modifications. The first modification is to increase the ac- curacy of rate estimation, which is achieved by computing a non-integer number of bits for arithmetic coding of the syntax elements. This leads to a more accurate cost computation and therefore a better mode decision. The second modification is to search and adjust the value of Lambda based on the char- acteristics of each coding stage. For the encoder used, this paper proposes to search multiple values of Lambda for the intra-4x4 mode decision. Moreover, a simple shift in Lambda value is proposed for motion estimation. Each of these modi- fications offers a certain gain in RDO performance, and, when all are combined, an average bit-rate saving of up to 7.0% can be achieved for the H.264/AVC codec while the same concept is applicable to the H.265/HEVC codec as well. The extra added complexity is contained to a certain level, and is also adjustable according to the processing resources available.

关键词： rate distortion optimization Lambda adjust-ment non-integer bit estimation H.264/AVC H265/HEVCvideo coding

Resilient Fixed-Order Distributed Dynamic Output Feedback Load Frequency Control Design for Interconnected Multi-Area Power Systems

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IEEE/CAA Journal of Automatica Sinica 2019年第5期6卷 1139-1151页

作者： Ali Azarbahram Amir Amini mahdi Sojoodi the Department of Electrical and Computer Engineering Ferdowsi University of MashhadMashhadIran the Department of Electrical and Computer Engineering Concordia UniversityMontrealQCCanada the Faculty of Electrical and Computer Engineering Tarbiat Modares UniversityTehran14115-143Iran

The paper proposes a novel H∞ load frequency control(LFC) design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback(DOF) tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multiarea power systems which also include uncertainties and timevarying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality(LMI) method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed(and decentralized) controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.

关键词： Dynamic output feedback control interconnected multi-area power systems load frequency control linear matrix inequalities power system control

Ground motion record simulation for structural analysis by consideration of spectral acceleration autocorrelation pattern

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 195-202页

作者： Alireza Azarbakht mahdi Sadeghi Mehdi Mousavi Department of Civil Engineering Faculty of Engineering Arak University

A novel approach is introduced to generate simulated ground motion records by considering spectral acceleration correlations at multiple periods. Most of the current reliable Ground Motion Record(GMR) simulation procedures use a seismological model including source, path and site characteristics. However, the response spectrum of simulated GMR is somewhat different when compared with the response spectrum based on recorded GMRs. More specifi cally, the correlation between the spectral values at multiple periods is a characteristic of a record which is usually different between simulated and recorded GMRs. As this correlation has a signifi cant infl uence on the structural response, it is needed to investigate the consistency of the simulated ground motions with actual records. This issue has been investigated in this study by incorporating an optimization algorithm within the Boore simulation technique. Eight seismological key parameters were optimized in order to achieve approximately the same correlation coeffi cients and spectral acceleration between two sets of real and simulated records. The results show that the acceleration response spectra of the synthetic ground motions also have good agreement with the real recorded response spectra by implementation of the proposed optimized values.

关键词： stochastic method simulation ground motion random vibration site amplifi cation EXSIM program

Applying Sliding Mode Control to Suppress Double Frequency Voltage Ripples in Single-phase Quasi-Z-source Inverters

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 671-681页

作者： Jaber Merrikhi Ahangarkolaei mahdi Izadi Tohid Nouri Department of Electrical Engineering Sari BranchIslamic Azad UniversitySariIran Department of Electrical Engineering Shahriar BranchIslamic Azad UniversityShahriarIran

The inherent double-line frequency ripple(DFR)of the single-phase quasi-Z-Source inverter(qZSI)strongly affects performance and design of the whole system,which requires hardware improvement methods such as additional semiconductor components or increasing the volume of capacitors and *** a result,hardware solutions increase the price,and the volume and also reduces reliability of the *** this paper,as a non-hardware solution,a sliding mode control(SMC)method is presented to control the voltage of the qZSI *** suppress the DFR,a second-order harmonic is injected into the capacitor reference *** and experimental results show that the introduced controller will have satisfactory results in reducing the DFR without any hardware changes in the qZSI,such as increasing the volume of the capacitor and inductor,adding a semiconductor,or increasing the frequency.A simulation model and experimental prototype are provided to demonstrate the validation of the effectiveness of the proposed controller.

关键词： Double-frequency ripple quasi-Z-source inverter sliding mode control

Evolutionary algorithm for optimization of multilayer coatings

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Chinese Physics B 2018年第10期27卷 531-536页

作者： mahdi Ebrahimi Mohsen Ghasemi Zeinab Sajjadi Department of Physics Payame Noor University Department of Physics Faculty of SciencesShahrekord University Department of Computer & Mathematics Sheikhbahaee University

In this paper, a new evolutionary algorithm, the well-known imperialist competition algorithm, is proposed for optimizing the optical thin-films. In this method, the process is modeled of the competition between countries as imperialists and their colonizing of others as colonies. This algorithm could be an appropriate alternative to some of the more popular algorithms for optimizing the optical thin-films for good performance. The polarizer and edge filter for example are designed by using the imperialist competition algorithm method and the results are compared with those from two optimization high-performance methods： the genetic algorithm and differential evolutionary algorithm. Based on these results,the performance of the imperialist competition algorithm method shows that this algorithm is not sensitive to the change of its parameters and it can be an important advantage for quickly achieving a global optimal point. On the other hand the results show a better ratio of P-polarization transmittance to S-polarization transmittance in the design of a 1540-nm polarizer, which is more appropriate than the results from the other two methods. In the second design, an edge filter with a lower number of layers and more uniform bandpass spectrum than the counterparts of those methods is obtained. These results indicate that the imperialist competition algorithm is a robust method for optical thin-film designs.

关键词： multilayers optimization thin-film imperialist competition algorithm

Evaluation of Feasible Interlinking Converters in a Bipolar Hybrid Microgrid

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Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 305-314页

作者： Parviz Najafi Abbas Houshmand Viki mahdi Shahparasti the Department of Electrical Engineering K.N.Toosi University of TechnologyTehranIran the Department of Electrical Engineering Polytechnic University of CataloniaBarcelonaSpain

A bipolar hybrid microgrid is a new topology which benefits from the advantages of both alternating current(AC)and direct current(DC)*** AC/DC converter is the key of this topology which has the following characteristics:being able to provide two equal pole voltages in DC side;complying with the standards of current quality at AC side;being able to control active and reactive power independently in AC side,and transmitting bidirectional *** this paper,two categories of power converters including single-stage and two-stage converters are proposed for this topology.A new cost-effective control strategy is added to the control of general grid-connected converter for each interlinking converter,and the control of autonomous DC-link pole voltage for both candidates is *** simulations based on the designed control strategies are conducted to validate the function of control strategies under the operation conditions of different DC *** performances of two selected interlinking converters with balanced and unbalanced DC loads are *** power quality of microgrid and total harmonic distortion(THD)analysis are demonstrated in grid-tied and islanded ***,semiconductor power loss simulations based on a closed-loop thermal network simulation are ***,the mutual effects of power loss and initial junction temperature are investigated.

关键词： Bipolar hybrid microgrid interlinking converter DC-link voltage balancing power loss distribution

Damaging of cemented carbide end mill with different grain sizes:experimental and simulation

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Rare Metals 2021年第3期40卷 671-678页

作者： Ali Amirnasiri mahdi Shafiei Haghshenas Nader Parvin Department of Mining and Metallurgical Engineering Amirkabir University of Technology(AUT)Tehran ***Iran

The main purpose of the current study was to investigate the effects of the size of WC grains on the damage evolution of WC-Co junk *** finite element method(FEM) simulation results showed that the finegrain(FG) tool retained its cutting edges radii longer than the coarse-grain(CG) *** event leads to the larger wear rate in the CG ***,FEM analysis indicated that through increasing the feeding rate,the wear rate and the cutting forces increased as *** observation of worn tool surface revealed that the formation of micro-pits,micro-cracks,scratching grooves and broken WC grains was among the common signs of the damage for both CG and FG ***,it was found that the defects are more intensive in the CG *** can be due to the lower boundary strength and less WC connectivity in the CG milling *** finer grains also decreased the mean free path in the Co binder and impeded the micro-cracks propagation in the material.

关键词： Cemented carbide Junk mill FEM simulation Wear Grain size

Reliable control of discrete-time linear systems with actuator failure

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Journal of Control and Decision 2020年第4期7卷 345-358页

作者： Mohammad mahdi Share Pasand Department of Electrical and Electronics Faculty of ElectricalMechanical and Civil EngineeringStandard Research InstitutePO Box 31585-163AlborzIran

A sufficient condition is given for robust stability of a discrete linear system in which an arbitrary portion of input channel is permanently attenuated or disconnected due to actuator *** partial disconnection/attenuation of the control input,is modelled as uncertainty and dealt with via a robust control *** proposed method enables one to design a controller in such a way that the closed loop system remains stable when any combination of input signals is disconnected if the open loop system is stable and fulfils some additional *** is shown that the linear quadratic regulator can guarantee reliable closed loop with some specific choices for weighting *** result is extended to unstable systems by assuming additional constraints on the failed *** to previously established results,the proposed conditions are easier to verify and applicable to a wider class of *** example is also included.

关键词： Reliable control robust control linear matrix inequality actuator failure