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Frontiers of Structural and Civil Engineering 2023年第7期17卷 1100-1116页

作者： Ahmadreza RAMEZANI mohammad Reza ESFAHANI javad SABZI Faculty of Engineering Ferdowsi University of MashhadMashhadIran

The performance of a new fiber-reinforced cementitious matrix(FRCM)system developed using custom-designed mortar and fabrics is investigated in this *** behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete *** beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening,and four specimens are designed to investigate their shear *** parameters investigated for flexural strengthening are the number of layers,span/depth ratio,and the strengthening *** previous studies,custom fabrics with similar axial stiffness are used in all strengthening methods in this *** the shear-strengthened specimens,the effects of the span/depth ratio and strengthening system type(fiberreinforced polymer(FRP)or FRCM)are *** proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity,provides sufficient bonding with the substrate,and prevents premature failure *** the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former,cement-based mortar performs better than epoxy.

关键词： fiber-reinforced cementitious matrix flexural strengthening shear strengthening carbon fiber-reinforced polymer shear span

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Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative structure-property relationship

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Frontiers of Environmental Science & Engineering 2014年第5期8卷 683-692页

作者： Davoud BEIKNEJAD mohammad javad CHAICHI Faculty of Chemistry University of Mazandaran Babolsar 47416-95447 Iron

In this paper the photolysis half-lives of the model dyes in water solutions and under ultraviolet （UV） radiation were determined by using a continuous-flow spectrophotometric method. A quantitative structure- property relationship （QSPR） study was carried out using 21 descriptors based on different chemometric tools including stepwise multiple linear regression （MLR） and partial least squares （PLS） for the prediction of the photolysis half-life （t1/2） of dyes. For the selection of test set compounds, a K-means clustering technique was used to classify the entire data set, so that all clusters were properly represented in both training and test sets. The QSPR results obtained with these models show that in MLR-derived model, photolysis half-lives of dyes depended strongly on energy of the highest occupied molecular orbital （EHoMO）, largest electron density of an atom in the molecule （ED^＋） and lipophilicity （logP）. While in the model derived from PLS, besides aforementioned EHOMO and ED^＋ descriptors, the molecular surface area （Sm）, molecular weight （M-W）, electronegativity （X）, energy of the second highest occupied molecular orbital （EHoMO- 1） and dipole moment （μ） had dominant effects on logt1/2 values of dyes. These were applicable for all classes of studied dyes （including monoazo, disazo, oxazine, sulfo- nephthaleins and derivatives of fluorescein）. The results were also assessed for their consistency with findings from other similar studies.

关键词： dye photolysis half-life quantitative structure-property relationship continuous-flow stepwise multiple linear regression partial least squares

Relative T-Injective Modules and Relative T-Flat Modules

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Chinese Annals of Mathematics,Series B 2011年第4期32卷 497-506页

作者： mohammad javad NIKMEHR Farzad SHAVEISI Department of Mathematics Faculty of Science K. N. Toosi University of Technology Tehran Iran Department of Mathematics Razi University Kermanshah Iran

Abstract Let T be a Wakamatsu tilting module. A module M is called （n, T）-copure injective （resp. （n, T）-copure flat） if εT^1（N, M） = 0 （resp. Г1^T（N, M） = 0） for any module N with T-injective dimension at most n （see Definition 2.2）. In this paper, it is shown that M is （n, T）-copure injective if and only if M is the kernel of an In（T）-precover f ： A → B with A ∈ ProdT. Also, some results on Prod T-syzygies are presented. For instance, it is shown that every nth Prod T-syzygy of every module, generated by T, is （n, T）-copure injective.

关键词： Wakamatsu tilting module (n T)-Copure injective module (n T)-Copure fiat module T-Projective dimension T-Injective dimension

Numerical demonstration of three-dimensional terahertz metamaterials based on the causality principle

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Chinese Physics B 2014年第2期23卷 518-523页

作者： Saeid Jamilan javad Nourinia mohammad Naghi Azarmanesh Department of Electrical Engineering Urmia University

A parameter retrieval algorithm based on the causality principle and Kramers-Kronig （KK） relations is employed to calculate the effective parameters of three-dimensional （3D） metamaterials. Using KK relations, the branch selecting problem, which is the challenge of effective parameter retrieval method, can be removed. To reveal the validity of the proposed algorithm, the constitutive refractive index of a homogeneous polymide cube is extracted. The result is in excellent agreement with the intrinsic refractive index of the polymide. Finally, the two terahertz metamaterials with 3D structures are designed and their effective parameters are then retrieved using the proposed algorithm. Numerical simulations are performed using the fuiI-wave electromagnetic solver, CST Microwave Studio.

关键词： metamaterial three-dimensional causality principle Kramers-Kronig relations

Peak displacement patterns for the performance-based seismic design of steel eccentrically braced frames

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 379-393页

作者： Ali Fakhraddini Hamed Saffari mohammad javad Fadaee Department of Civil Engineering Shahid Bahonar University of Kerman

Performance-based seismic design(PBSD) aims to assess structures at different damage states. Since damage can be directly associated to displacements, seismic design with consideration of displacement seems to be logical. In this study, simple formulae to estimate the peak floor displacement patterns of eccentrically braced frames(EBFs) at different performance levels subjected to earthquake ground motions are proposed. These formulae are applicable in a PBSD and especially in direct displacement-based design(DDBD). Parametric study is conducted on a group of 30 EBFs under a set of 15 far field and near field accelerograms which they scaled to different amplitudes to adapt various performance levels. The results of thousands of nonlinear dynamic analyses of EBFs have been post-processed by nonlinear regression analysis in order to recognize the major parameters that influence the peak displacement pattern of these frames. Results show that suggested displacement patterns have relatively good agreement with those acquired by an exact nonlinear dynamic analysis.

关键词： performance-based seismic design direct displacement-based design displacement pattern eccentrically braced frames steel building

Application of reliability-centered maintenance for productivity improvement of open pit mining equipment:Case study of Sungun Copper Mine

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Journal of Central South University 2014年第6期21卷 2372-2382页

作者： Amin Moniri Morad mohammad Pourgol-mohammad javad Sattarvand Department of Mining Engineering Sahand University of Technology Department of Mechanical Engineering Sahand University of Technology

Equipment plays an important role in open pit mining industry and its cost competence at efficient operation and maintenance techniques centered on reliability can lead to significant cost *** application of optimal maintenance process was investigated for minimizing the equipment breakdowns and downtimes in Sungun Copper *** results in the improved efficiency and productivity of the equipment and lowered expenses as well as the increased profit *** field operating data of 10 trucks are used to estimate the failure and maintenance profile for each component,and modeling and simulation are accomplished by using reliability block diagram *** analysis was then conducted to select proper probabilistic model for maintenance *** reliability of the system was evaluated and importance of each component was computed by weighted importance measure *** analysis led to identify the items with critical impact on availability of overall equipment in order to prioritize improvement ***,the availability of trucks was evaluated using Monte Carlo simulation and it is revealed that the uptime of the trucks is around 11000 h at 12000 operation ***,uncertainty analysis was performed to account for the uncertainty sources in data and models.

关键词： operating costs maintenance mining dump truck reliability availability uncertainty

Design and optimization of a nano-antenna hybrid structure for solar energy harvesting application

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Chinese Physics B 2021年第9期30卷 606-617页

作者： mohammad javad Rabienejhad Mahdi Davoudi-Darareh Azardokht Mazaheri Optics and Laser Science and Technology Research Center Malek Ashtar University of TechnologyShahinshahrIran Faculty of Science Department of PhysicsMalek Ashtar University of TechnologyShahinshahrIran Department of Physics University of IsfahanIran

A novel hybrid structure with high responsivity and efficiency is proposed based on an L-shaped frame nano-antenna(LSFNA)array for solar energy harvesting ***,two types of LSFNAs are designed and optimized to enhance the harvesting characteristics of traditional simple electric dipole nano-antenna(SEDNA).The LSFNA geometrical dimensions are optimized to have the best values for the required input impedance at three resonance wavelengths ofλ_(res)=10μm,15μm,and 20μ*** the LSFNAs with three different sizes are modeled like a planar spiral-shaped array(PSSA).Also,a fractal bowtie nano-antenna is connected with the PSSA in the array *** proposed hybrid structure consists of two main elements:(I)Three different sizes of the LSFNAs with two different material types are designed based on the thin-film metal-insulator-metal diodes that are a proper method for infrared energy harvesting.(Ⅱ)The PSSA gap is designed based on the electron field emission proposed by the Fowler-Nordheim theory for the array ***,the proposed device is *** results show that the PSSA not only has an averaged 3-time enhancement in the harvesting characteristics(such as return loss,harvesting efficiency,etc.)than the previously proposed structures but also is a multi-resonance wide-band ***,the proposed antenna takes up less space in the electronic circuit and has an easy implementation process.

关键词： field electron emission infrared metal-insulator-metal(MIM)diode nano-antenna photovoltaic effects rectification solar energy harvesting

Design and optimization of nano-antenna for thermal ablation of liver cancer cells

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Chinese Physics B 2021年第4期30卷 574-585页

作者： mohammad javad Rabienejhad Azardokht Mazaheri Mahdi Davoudi-Darareh Optics and Laser Science and Technology Research Center Malek Ashtar University of TechnologyShahinshahrIran Department of Physics University of IsfahanIran Faculty of Science Malek Ashtar University of TechnologyShahinshahrIran

One method of cancer therapy is to utilize nano-antenna for thermal *** this method,the electromagnetic waves emitted from the nano-antenna are absorbed by the tissue and lead to heating of cancer *** temperature of cancer cells reaches a threshold,they will begin to *** this purpose,an L-shaped frame nano-antenna(LSFNA) is designed to introduce into the biological ***,the radiation characteristics of the LSFNA such as near and far-field intensities,directivity,and sensitivity to its gap width are studied to the optimization of the *** bio-heat and Maxwell equations are solved using the finite element *** prevent damage to healthy tissues in this method,the antenna radiation must be completely controlled and performed ***,penetration depth,special absorption rate,temperature distribution,and the fraction of tissue necrosis are analyzed in the biological *** is why the design and optimization of the nano-antennas as a radiation source is ***,a pulsed source is used to excite the ***,focusing and efficiency of the nano-antenna radiation on the cancer cell is tuned using an adjustable liquid crystal *** focus of this lens is changing under an electric field applied to its surrounding cathode.

关键词： cancer therapy directivity far-field intensity hyperthermia liver cancer nano-antenna thermalablation tunable liquid crystal lens

A Chebyshev/Legendre polynomial interpolation approach for fingerprint orientation estimation smoothing and prediction

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第12期11卷 976-988页

作者： Ashkan TASHK mohammad Sadegh HELFROUSH mohammad javad DEHGHANI Faculty of Electrical Engineering Shiraz University of Technology Shiraz Iran

We introduce a novel coarse ridge orientation smoothing algorithm based on orthogonal polynomials, which can be used to estimate the orientation field (OF) for fingerprint areas of no ridge information. This method does not need any base information of singular points (SPs). The algorithm uses a consecutive application of filtering-and model-based orientation smoothing methods. A Gaussian filter has been employed for the former. The latter conditionally employs one of the orthogonal polynomials such as Legendre and Chebyshev type I or II, based on the results obtained at the filtering-based stage. To evaluate our proposed method, a variety of exclusive fingerprint classification and minutiae-based matching experiments have been conducted on the fingerprint images of FVC2000 DB2, FVC2004 DB3 and DB4 databases. Results showed that our proposed method has achieved higher SP detection, classification, and verification performance as compared to competing methods.

关键词： Coherence Consistency Fingerprint orientation Legendre/Chebyshev orthogonal polynomials

Performance analysis of a tuned point absorber using SPH calm water and wave tank simulations

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Journal of Ocean Engineering and Science 2024年第5期9卷 409-436页

作者： Kaveh Soleimani mohammad javad Ketabdari Department of Maritime Engineering Amirkabir University of TechnologyTehranIran

In this paper,two smoothed particle hydrodynamics(SPH)models,namely SPH-W and SPH-C were used to evaluate the motion response of a point absorber wave energy converter(WEC).In the SPH-W model,a long wave flume was constructed and a long simulation was performed to obtain the motion response of the *** the SPH-C model,the SPH method is only used to find the hydrodynamic coefficients of the device by analysing a few seconds of free-decaying motion of WEC in calm water in a much smaller numerical ***,these coefficients were inserted in the equation of motion of a heaving WEC that was solved using a 4th order Runge-Kutta(ODE45)solver in ***,the energy conservation property of the WCSPH model was examined through a standing wave benchmark ***,the wavepoint absorber interaction was *** the simulation time for SPH-C model is much smaller than that of SPH-W,it gave almost similar results for the motion response of *** two models were used to evaluate the effects of the control force and the draft of a cone-cylinder point absorber on its hydrodynamic *** results showed that compared to the effect of the supplementary inertia,changes in the draft of the WEC have a small influence on its hydrodynamic *** buoy draft has an inverse relationship with both added mass and damping ***,increasing the supplementary mass increases the added mass and decreases the hydrodynamic damping coefficients.

关键词： Point absorber Power take-off Control forces SPH wave tank test SPH calm water test DualSPHysics