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SYNTHESIS AND CHARACTERIZATION OF SCHIFF-BASE-CONTAINING POLYAMIDES

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Chinese Journal of Polymer Science 2011年第2期29卷 149-155页

作者： Mousa Ghaemy hossein Mighani Raouf Alizadeh Department of Chemistry Mazandaran UniversityBabolsarIran

A series of new Schiff base polyamides（PAs） were synthesized by polycondensation of benzilbisthiosemicarbazone diamine（LH6） with different commercially available aliphatic and aromatic diacid chlorides. The monomer and all the PAs were characterized by FTIR,^1H-NMR,and elemental *** prepared polyamides showed inherent viscosities in the range of 0.30-0.36 dL/g in DMF at 25℃,indicating their moderate molecular *** PAs were completely soluble in aprotic polar solvents such as dimethylformamide（DMF）,N-methylpyrolidone（NMP）, tetrachloroethane（TCE）,dimthylsulfoxide（DMSO） and also in H_2SO_4 and partially soluble in THF,acetone and chloroform at room *** analysis showed that these PAs were practically amorphous and exhibited 10%weight loss above 220℃.

关键词： Polyamides Schiff base polymers Solubility Thermal stability

Er^(3+) ion concentration effect on transient and steady-state behavior in Er^(3+):YAG crystal

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Chinese Physics B 2014年第10期23卷 248-253页

作者： Asadpour Seyyed hossein Rahimpour Soleimani H Department of Physics University of Guilan

The effect of Er3＋ ion concentration on transient and steady-state behavior in 45-nm Er3＋：YAG crystal is investigated. It is shown that by changing the signal field, the coherent field and the concentration of Er3＋ ions in the crystal, the absorption, dispersion, and group index of the weak probe field can be adjusted. Also, it is found that the probe absorption occurs in the presence of population inversion and probe amplification is obtained in the absence of population inversion.

关键词： Er3+ ion concentration absorption dispersion group index

Target optimization for a 10-MeV E-beam neutron converter

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Nuclear Science and Techniques 2010年第2期21卷 69-71页

作者： TABBAKH Farshid KHALAFI hossein Institute of Nuclear Science and Technology Irradiation and Application Research School Atomic Energy Organization of Iran Tehran Iran Institute of Nuclear Science and Technology Atomic Energy Organization of Iran Tehran *** Iran

Accelerator-based target design and optimization is an approach for neutron generation. The target plays an important role for a neutron source on an electron accelerator. For optimizing a neutron source using 10 MeV electron beams of Rhodotron-TT200, Pb, Ta, or W alloys with Be were calculated as photo-neutron converter. The neutron yield, flux and energy were simulated using the MCNPX code. The results indicate that a 10 MeV electron beam is capable of producing high-intensity neutron flux of 1013n·cm–2·s–1 with average energy of 0.8 MeV.

关键词：优化目标电子束中子源电子加速器中子通量平均能量生成方法中子产额

Coupled and splitting bedload sediment transport models based on a modified flux-wave approach

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International Journal of Sediment Research 2021年第1期36卷 38-49页

作者： hossein Mahdizadeh Soroosh Sharifi Department of Civil Engineering University of Birjand Department of Civil Engineering University of Birmingham

Numerical modeling of free-surface flow over a mobile bed with predominantly bedload sediment transport can be done by solving the shallow water and Exner equations using coupled and splitting *** coupled method uses a coupling of the governing equations at the same time step leading to a non-conservative *** splitting method solves the Exner and the shallow water equations in a separate manner,and is only capable of modeling weak free-surface and bedload *** the current study,an extended version of a Godunov-type wave propagation algorithm is presented for modeling of morphodynamic systems using both coupled and splitting *** the introduced coupled method the entire morphodynamic system is solved in the form of a conservation *** the splitting technique,a new wave Riemann decomposition is defined which enables the scheme to be utilized for mild and strong *** consider the bedload sediment discharge within the Exner equation,the Smart and Meyer-Peter & Miiller formulae are *** was found that the coupled solution gives accurate predictions for all investigated flow regimes including pro pagation over a dry-state using a Courant-Friedrichs-Lewy(CFL) number equal to ***,the splitting method was able to model all flow regimes with a lower CFL number of 0.3.

关键词： Bedload sediment transport Coupled solution Flux-wave method Shallow water equations Splitting technique Wave propagation algorithm

Cavity effect on Rayleigh wave dispersion and P-wave refraction

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Earthquake Engineering and Engineering Vibration 2021年第1期20卷 79-88页

作者： hossein Rahnema Sohrab Mirassi Giancarlo Dal Moro Department of Civil and Environmental Engineering Shiraz University of TechnologyShirazIran Department of Civil Engineering Shahrekord BranchIslamic Azad UniversityShahrekordIran Institute of Rock Structure and Mechanics Academy of Sciences of the Czech RepublicPragueCzech Republic

Sinkholes and cavities can represent serious hazards to human safety and urban infrastructures,cause roadbed subsidence,and so *** is therefore essential to evaluate various sinkholes in different depths and sizes to assess the risk of *** paper evaluates the effect of different cavities on Rayleigh-wave propagation and body(P)wave ***(R)wave propagation is analyzed according to the classical multi-channel analysis of surface waves(MASW)method also considering the R-wave *** seismic traces are computed by means of finite element modeling(FEM)for cavity and intrusion at different depths and ***,field acquisition data is used to verify the detection effect of a cavity on R-and *** results show that the presence of backscattered R-waves and the changes in the R-wave velocity spectrum can help in cavity *** possible evidence is represented by significant changes in the refraction travel times over the cavity *** can be concluded that the field data are in good agreement with the synthetic,and it could be effective to consider the results of both R-and P-wave analysis in order to efficiently identify the cavities.

关键词： R-wave velocity spectrum P-wave refraction cavity intrusion backscattered waves finite element modeling(FEM) MASW method

Efficient Wind Turbine Generation Planning for Decreasing Distribution System Company Payments in Real Applications

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Journal of Modern Power Systems and Clean Energy 2022年第1期10卷 81-90页

作者： Mohammad Hasan Hemmatpour Mohammad hossein Rezaeian Koochi Electrical Engineering Department Faculty of EngineeringJahrom UniversityJahromIran Department of Electrical Engineering Shahid Bahonar University of KermanKermanIran

Wind energy has posed new challenges in both transmission and distribution systems owing to its uncertain nature. The effect of wind turbines (WTs) on the actual payments charged by upstream networks to distribution system companies (DISCOs) is one challenge. Moreover, when the grid-connected inverters of WT operate in the lead or lag modes, WTs absorb or inject reactive power from the system. This paper proposes an approach to assess the importance of operation modes of WTs to minimize the costs by DISCOs in the presence of system uncertainties. Accordingly, an optimization problem is formulated to minimize the costs to DISCO by determining the optimal locations and sizes of WTs in optimally reconfigured distribution systems. In addition, an improved vector-based swarm optimization (IVBSO) algorithm is proposed because it is highly suitable for vector-based problems. Two distribution systems are used in the simulations to evaluate the proposed algorithm. Firstly, the capabilities of the IVBSO algorithm to determine better solutions over other heuristic algorithms are confirmed using the IEEE 33-bus test system. Secondly, the BijanAbad distribution system (BDS) is used to demonstrate the effectiveness of the proposed optimization problem. Accordingly, the distribution system model, cumulative distribution function of wind speed, and load profile are all extracted from the actual data of the BijanAbad region. Finally, the optimization problem is applied to BDS in both the lead and lag modes of WTs. Results indicate that the total costs of DISCO are lower when WTs operate in the lag mode than in the lead mode.

关键词： Distribution system companies(DISCOs) improved vector-based swarm optimization(IVBSO) reconfiguration wind turbine operation mode

Stresses induced by post-tensioned anchor in jointed rock mass

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Journal of Central South University 2015年第4期22卷 1463-1476页

作者： Alan Showkati Parviz Maarefvand hossein Hassani Faculty of Mining and Metallurgical Engineering Amirkabir University of Technology

A new analytical study on stresses around a post-tensioned anchor in rocks with two perpendicular joint sets is presented. The assumptions of orthotropic elastic rock with plane strain conditions are made in derivation of the formulations. A tri-linear bond-slip constitutive law is used for modeling the tendon-grout interface behavior and debonding of this interface. The bearing plate width is also considered in the analysis. The obtained solutions are in the integral forms and numerical techniques that have been used for evaluation. In the illustrative example given, the major principal stress is compressive in the anchor free zone and compressive stress concentrations of 815 k Pa and 727 k Pa(for the anchor load of 300 k N) are observed under the bearing plate and the bond length proximal end, respectively. However, large values of tensile stresses with the maximum of-434 k Pa are formed at the bond length distal end. The results obtained using the proposed solution are compared very those of numerical method(FEM).

关键词： post-tensioned anchor jointed rock stress distribution analytical solution tri-linear bond-slip model bond length bearing plate

Effects of Annealing on the Fabrication of Al-TiAl3 Nanocomposites Before and After Accumulative Roll Bonding and Evaluation of Strengthening Mechanisms

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 636-650页

作者： Zohreh Yazdani Mohammad Reza Toroghinejad hossein Edris Department of Materials Engineering Isfahan University of Technology84156-83111 IsfahanIran

The strengthening mechanisms of Al-TiAl_(3) nanocomposite, fabricated using cold roll bonding, annealing, and accumulative roll bonding(ARB) on Al sheets sandwiching with pure Ti powder were investigated in the present study. With annealing at 590 ℃ for 2 h, TiAl_(3) intermetallic compound was formed. After subsequent ARB process up to 5 cycles, final composite consists of ultrafine Al grains of less than 500 nm with TiAl_(3) particles larger than 200 nm. The strength and hardness of the final composite are 2.5 and 3.5 times the initial values, with an ultimate tensile strength of 400 MPa, which is dominated by grain-boundary strengthening due to the ultrafine Al grains, and Orowan strengthening due to the small TiAl_(3) particles. For comparison, an alternative fabrication route of cold roll bonding–ARB–annealing was also studied. This study showed that annealing before ARB is a critical factor in producing an ultrafine grain structure containing TiAl_(3) particles.

关键词： Composite Annealing Strength Microstructure Al

Zn(NO_3)_2·6H_2O/2,4,6-trichloro-1,3,5-triazine(TCT) a mild and selective system for nitration of phenols

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Chinese Chemical Letters 2010年第4期21卷 403-406页

作者： Firouzeh Nemati hossein Kiani Department of Chemistry Faculty of ScienceSemnan UniversitySemnanIran

Certain phenols and naphthols were nitrated regioselectively with Zn(NO)·6HO/TCT in acetonitrile as solvent at room temperature and short reaction time in good *** reaction condition was *** is a cheap and commercial... 详细信息

关键词： Nitration Phenols 2 4 6-Trichloro-l 3 5-triazine Regioselective