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Rare Metals 2009年第1期28卷 98-101页

作者： H. Hasannejad T. Shahrabi M. Aliofkhazraei Materials Engineering Department Faculty of EngineeringTarbiat Modares UniversityTehranIran

Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.

关键词： nano cerium oxide films acetic acid aluminum alloy electrochemical property microstructure

Spherical Logistic Distribution

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Communications in Mathematics and Statistics 2020年第2期8卷 151-166页

作者： M.Moghimbeygi M.Golalizadeh Department of Statistics Tarbiat Modares UniversityTehranIran

Some of the spherical distributions can be constructed through proper transformation of the densities on *** the logistic density on the Euclidean space has similar behavior to the normal distribution,it is of interest to extend it for spherical *** this paper,we introduce spherical logistic distribution on the unit sphere and then study relevant statistical inferences including parameters estimation through method of moments and maximum likelihood *** is shown that the spherical logistic distribution is a multimodal distribution with the marginal logistic density *** density has rotational symmetry property and this plays a key role to drive some important results related to first two *** investigate the proposed density in more details,some simulation studies along with analyzing real-life data are also considered.

关键词： Bessel function Logistic density Bimodality Spherical distribution Rotational symmetry

Comparative life table analysis of Tetranychus urticae （Acari Tetranychidae） on 14 soybean genotypes

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Insect Science 2011年第5期18卷 541-553页

作者： Amin Sedaratian Yaghoub Fathipour Saeid Moharramipour Department of Entomology Faculty of Agriculture Tarbiat Modares University Tehran Iran

The life table parameters of two-spotted spider mite （TSSM）, Tetranychus urticae Koch, on 14 soybean genotypes （Sari, Sahar, Tellar, Zane, Ks3494, LI7, Dpx, 032, 033, Clark, Hill, 127, Tms and Williams） were evaluated at 28 ±1℃, 65% ± 5% RH and a photoperiod of 16 ： 8 h L ： D. The survivorship data （lx） of adult females were fitted to the Weibull frequency distribution model in all genotypes tested. Based on the Weibull parameters, the survival curve was type I on all genotypes, which indicated that the mortality mostly occurred in old individuals. Furthermore, two mathematical models （Analytis and Enkegaard） were fitted to age-specific fecundity data （mx）. The highest intrinsic rate of increase （rm） was recorded on L17 （0.392） and the lowest values of this parameter were obtained on Tms （0.233）, Hill （0.236）, 032 （0.236）, 127 （0.237） and Clark （0.240）. In addition, net reproductive rate （R0） and finite rate of increase （λ） of the TSSM had the highest value on L17 as 45.521 and 1.475, respectively. The lowest values of these parameters were recorded on Tms as 12.149 and 1.258, respectively. Doubling time （DT） varied significantly on different genotypes and the shortest and longest values of this period were obtained on L17 and 032, respectively. Our findings revealed that Tms, Hill, 032, 127 and Clark were less suitable genotypes, suggesting that they are more resistant to the TSSM than the other genotypes.

关键词： fecundity life table parameters resistance soybean two-spotted spider mite

Coinfection of the secondary symbionts,Hamiltonella defensa and Arsenophonus *** to the performance of the major aphid pest,Aphis gossypii(Hemiptera:Aphididae)

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Insect Science 2020年第1期27卷 86-98页

作者： Aida Ayoubi Ali Asghar Talebi Yaghoub Fathipour Mohammad Mehrabadi Faculty of Agriculture Department of EntomologyTarbiat Modares UniversityTehranIran

Bacterial endosymbionts play important roles in ecological traits of *** this study,we characterize the bacterial endosymbionts of *** collected in Karaj,Iran and their role in the performance of the *** results indicated that beside Buchnera aphidicola,***,also harbors both Hamiltonella defensa and Arsenophonus *** PCR(qPCR)results revealed that the populations of the endosymbionts increased throughout nymphal development up to adult emergence;thereafter,populations of Buchnera and Arsenophonus were diminished while the density of *** constantly *** reduction caused prolonged development and no progeny ***,secondary symbiont reduction led to reduction of the total life span and intrinsic rate of natural increase as well as appearance of the deformed dead offspring in comparison with the control *** of the secondary symbionts did not affect parasitism rate of the aphid by the parasitic wasp Aphidius *** these findings showed that *** and Arsenophonus contributed to the fitness of *** by enhancing its performance,but not through parasitoid resistance.

关键词： Arsenophonus Buchnera aphidicola cotton aphid Hamiltonella defensa parasitism resistance

Inhibiting soil loss and runoff from small plots induced by an individual freeze-thaw cycle using three rangeland species

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International Soil and Water Conservation Research 2020年第3期8卷 228-236页

作者： Milad Hatefi Seyed Hamidreza Sadeghi Reza Erfanzadeh Morteza Behzadfar Department of Watershed Management Engineering Faculty of Natural ResourcesTarbiat Modares UniversityIran Department of Rangeland Management Faculty of Natural ResourcesTarbiat Modares UniversityNoorIran

This study investigated the role of three rangeland species *** trichophorum,Medicago sativa,and Lolium prenne on mitigating of effects of a freeze-thaw(FT)cycle on runoff generation and soil loss from small experimental *** plots(0.5×0.5m)were prepared in three replicates for control(i.e.,under a FT cycle only)and treatments(i.e.,individually planted with the study species and subject to a FT cycle).The treated plots were then placed at a slope of 20%and subjected to simulated rainfall with intensity of 70 mm h-1 and 30 min *** results of the study showed a significant effect(P<0.05)of the plants on controlling runoff and soil loss after a FT ***,the detrimental effects of the FT cycle due to performance of ice lenses and formation of an active melting layer in the soil surface were ameliorated by the presence of litter on the soil and root-binding effect of the *** to runoff increased by 54,111 and 10%,runoff volume decreased by 27,68 and 0.4%and soil loss changed by-34,-62,and+6.5%in the plots planted with ***,*** and ***,*** results of the current study indicated that *** had the maximum benefit on reducing runoff and soil loss from the plots undergoing a FT cycle.

关键词： Biological measures Frosted soil Plant binding effects Soil hydrology

Numerical and experimental study of twin-fluid two-phase internal-mixing atomizer to develop maximum entropy method

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Chinese Journal of Aeronautics 2020年第9期33卷 2281-2294页

作者： Alireza MOHAMMADI Fathollah OMMI Department of Mechanical Engineering.tarbiat modares university Tehran 14115-111Iran

This paper presents an analytical, numerical, and experimental study on atomization characteristics and droplet distribution of a twin-fluid two-phase internal mixing atomizer to develop a Maximum Entropy Method(MEM). A two-phase Eulerian-Lagrangian method is utilized for atomization modeling of the inside and outside atomizer. In order to modify energy and momentum sources in the MEM, parametric studies are performed, and experimental tests are carried out to verify the results by applying the shadowgraph method. An advanced test stand is developed to prepare a wide range of changes in atomization characteristics and mixing ratios. A high degree of consistency is found between numerical results from the developed MEM and experimental tests with different gas-phase pressures and liquid flow rates. The droplet diameter and velocity distribution are reviewed based on various Weber numbers, sources of energy, and momentum. Turbulence modeling assists to estimate the breakup length and time scale precisely in the developed MEM, and distribution ranges with mean values are achieved. With reference to a strong correlation between upstream turbulence flow and the developed MEM verified by experimental tests, an ideal droplet size and velocity distribution prediction is observed.

关键词： Atomization Droplet distribution Internal-mixing atomizer Maximum entropy method Shadowgraph technique Test stand

Increased photo-catalytic removal of sulfur using titania/MWCNT composite

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Journal of Central South university 2016年第5期23卷 1066-1070页

作者： Molood Barmala Abdolsamad Zarringhalam Moghadam Mohammad Reza Omidkhah Chemical Engineering Department Tarbiat Modares UniversityJalal Ale Ahmad Highway

Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic *** effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction rate and photo-catalytic removal efficiency of dibenzothiophene(DBT) from n-hexane solution was investigated using a 9 W UV *** results show that the addition of nanotubes improves the photo-catalytic properties of TiO_2 by two factors;however,the DBT removal rate versus MWCNT content is found to follow a bimodal *** factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT ***,large quantities of MWCNTs prevent light absorption by the solution and decrease removal *** contrast,a low dosage of MWCNT causes recombination of the electron holes,which also decreases the DBT removal *** optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 m L of sol.

关键词： photo oxidation desulfurization sol-gel titania multi wall carbon nano tube (MWCNT)

A New Approach to Plane Failure of Rock Slope Stability Based on Water Flow Velocity in Discontinuities for the Latian Dam Reservoir Landslide

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Journal of Mountain Science 2011年第2期8卷 124-130页

作者： Morteza AHMADI Majid ESLAMI Department of Mining Engineering Tarbiat Modares University Ghaem Consulting Engineers

The stability of slopes is always of great concern in the field of rock engineering. The geometry and orientation of pre-existing discontinuities show a larger impact on the behavior of slopes that is often used to describe the measurement of the steepness, incline, gradient, or grade of a straight line. One of the structurally controlled modes of failure in jointed rock slopes is plane failure. There are numerous analytical methods for the rock slope stability including limit equilibrium, stress analysis and stereographic methods. The limiting equilibrium methods for slopes under various conditions against plane failure have been previously proposed by several investigators. However, these methods do not involve water pressure on sliding surfaces assessments due to water velocity and have not yet been validated by case study results. This paper has tried to explore the effects of forces due to water pressure on discontinuity surfaces in plane failure through applying the improved equations. It has studied the effect of water flow velocity on sliding surfaces in safety factor, as well. New equations for considering water velocity (fluid dynamics) are presented. To check the validity of the suggested equations, safety factor for a case study has been determined. Results show that velocity of water flow had significant effect on the amount of safety factor. Also, the suggested equations have higher validity rate compared to the current equations.

关键词： Plane Failure Limit Equilibrium Safety Factor Water Velocity

Narrow-band interference suppression in Time-Division-Duplex CDMA systems using preprocessing techniques

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Journal of Systems Engineering and Electronics 2008年第5期19卷 893-895页

作者： Paeiz Azmi Nooshin Tavakkoli Dept. of Electrical Engineering Tarbiat Modares Univ

This letter presents two preprocessing techniques for narrow-band interference （NBI） rejection in Time- Division-Duplex （TDD） CDMA systems. In the proposed methods, at the transmitter, by using Karhaunen-Loeve Transform and Discrete Fourier Transform, the transmitted power is set to zero in the directions of the eigenvectors that will be severely contaminated by NBI; and therefore less part of the transmitted energy will be polluted by NBI in channel. The processing is transferred from receiver to transmitter, and thus the complexity of the receiver is significantly reduced. It is assumed that channel state information can be estimated at the transmitter because in symmetric TDD systems each receiver in turn also acts as a transmitter.

关键词： CDMA narrow-band interference pre-processing

Sediment contribution from different geologic formations and land uses in an Iranian small watershed,case study

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International Journal of Sediment Research 2017年第2期32卷 210-220页

作者： Seyed Hamidreza Sadeghi Saeed Najafi Alireza Riyahi Bakhtiari Department of Watershed Management Engineering Faculty of Natural ResourcesTarbiat Modares University Department of Environmental Sciences Faculty of Natural ResourceTarbiat Modares University

Many intra and extra problems occurred due to unsustainable human use of natural resources leading to increasing sediment loads in the ***,few studies have been comprehensively conducted in progressing countries to prioritize sediment sources from different points of views,particularly in some countries like Iran where such valuable information is essential for proper watershed resources *** present study was therefore planned to assess the importance of potential sediment sources viz.,spatial sources(geologic units) and source types(land use units) in sediment yield in Idelo watershed as one of the important sub-watersheds of Sefidrood large Watershed in Zanjan Province,Iran,using composite *** addition,the results of the sediment fingerprinting approach were compared with those of field measurement data obtained from studying soil erosion types(viz.,sheet,rill and gully erosion).Toward this attempt,16 tracers were detected in different geologic units and land uses and the sediment yielded at the watershed *** results showed that the composite fingerprints of the different geologic units comprising As,N,Cu,Zn,OC and Co tracers could correctly distinguish 86% of the sediment source *** red gypsiferous marl contributed 85 percent in sediment *** regard to source types,the optimum composite fingerprint encompassed only N and Cu and provided a discriminatory efficiency of 90%.Besides that,the rangelands with 48.8% study area coverage had a significant contribution of 88% in sediment *** field measurements confirmed the reliability of results of fingerprinting approach in apportioning watershed scale sediment sources on the base of consistency of the two sets of *** was also understood from the results,besides successful applicability of composite fingerprinting in assessing the provenance of the sediment yielded at the watershed outlet that the geologic formations and land use types played differe

关键词： Composite fingerprinting Multivariate mixing model Soil erosion Spatial sources Source types