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51.
Ramin Ghahremanzadeh Mojtaba Mirhosseini Moghaddam Ayoob Bazgir Mohammad Mehdic Akhondi 《中国化学》2012,30(2):321-326
A four‐component reaction in the presence of Alum [KAl(SO4)2·12H2O] as an inexpensive and reusable catalyst using the ionic liquid as an effective green reaction media is reported. 相似文献
52.
53.
Maliheh Khatibi Moghaddam Amir Reza Attari Mir Mojtaba Mirsalehi 《Photonics and Nanostructures》2010,8(1):47-53
We investigate a photonic crystal (PC) waveguide coupler which is formed by two closely spaced linear waveguides in a two-dimensional triangular lattice of air holes. Our study shows that shifting one row of the air holes between the waveguides affects the dispersion curves of the guided modes and if the triangular lattice of air holes between the waveguides is replaced by a rectangular lattice, this modification results in an ultra-short coupling structure with coupling length less than 3a, where a is the lattice constant. Also, we investigate the effect of changing the radii of air holes that are adjacent to or between the waveguides on the coupling length and show that increasing the radius of air holes between the waveguides decreases the coupling length. We analyze the output spectrum of an ultra-short channel drop filter designed based on this structure. 相似文献
54.
The purpose of this study was to investigate the effect of three vitrification procedures [conventional straw (CS), open pulled straw (OPS) and closed pulled straw (CPS)] on the development of two-cell mouse embryos. Two-cell mouse embryos were randomly divided into vitrified and non-vitrified control groups. Embryos in the vitrified group were cryopreserved within a combination of 5.5 M ethylene glycol and 1M sucrose as cryoprotectants, loaded within three different straws (CS, OPS and CPS) and warmed in stepwise sucrose solutions. The survived embryos from each procedure were cultured in human tubal fluid (HTF). The non-vitrified control embryos were also cultured in the same manner. The rates of the development in all the groups were daily determined and statistically compared. On day 4 of the cultivation period, several expanded blastocysts from each group were randomly selected and stained either with propidium iodide (PI) and bisbenzimide or with terminal transferase- mediate DNA end labeling (TUNEL) Technique. The mean number of the inner cell mass (ICM), trophoectoderm (TE), necrotic and apoptotic cells were counted and statistically compared. The survival rate of embryos in CPS was significantly higher than that in OPS and CS. The rate of hatched blastocysts did not differ in the three vitrification procedures, but in comparison with that of the control, CS and OPS showed a significant reduction. The mean number of ICM and TE decreased in CS and OPS, whereas in CPS it was almost identical to that of the control. The incidence of apoptosis and necrosis appeared to be almost similar in all the groups. In conclusion, CPS seems to be an effective, easy and rapid method for the cryopreservation of two-cell mouse embryos. 相似文献
55.
Gholam‐Reza Nejabat Mehdi Nekoomanesh Hassan Arabi Hamid Salehi‐Mobarakeh Gholam‐Hossein Zohuri Mojtaba Omidvar Stephen A. Miller 《Journal of polymer science. Part A, Polymer chemistry》2013,51(3):724-731
Various elastomeric polypropylenes (PPs) are synthesized through homogeneous propylene polymerization with metallocene catalyst (2‐PhInd)2ZrCl2 in the presence of different cocatalyst mixtures: triethylaluminum (TEA)/methylaluminoxane (MAO) or triisobutylaluminum (TIBA)/MAO in the range of AlAlR3/AlMAO = 0.0–0.9. The cocatalyst formulation impacts the resultant polymer microstructure and the thermal and dynamic mechanical properties of the produced PPs. 13C NMR analysis of the polymers reveals essentially atactic PP, with mmmm = 7.9%, when AlAlR3/AlMAO = 0.0. The mmmm pentad content is maximized when AlAlR3/AlMAO = 0.8; for TIBA, mmmm = 23.5%; and for TEA, mmmm = 17.6%. Differential scanning calorimetry analysis and dynamic mechanical thermal analysis corroborate these findings. Specifically, Tm, ΔHm, and Tg are essentially maximized under these conditions, and the minimum damping is observed for AlAlR3/AlMAO = 0.6–0.8. 1H NMR analysis of the mixtures of catalyst and cocatalysts (without monomer) shows very minor differences for [Zr]:AlAlR3 in the range of 1:1–1:5. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
56.
Mohammad Mahdi Najafpour Mojtaba Amini Mojtaba Bagherzadeh Davar M. Boghaei Vickie McKee 《Transition Metal Chemistry》2010,35(3):297-303
A manganese(II) complex of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) has been synthesized and characterized by single-crystal
X-ray diffraction, elemental analyses, IR, and UV–Vis spectroscopic techniques. Oxidation of alcohols to their corresponding
aldehydes and ketones was conducted by this catalyst using oxone (2KHSO5·KHSO4·K2SO4) as an oxidant under biphasic reaction conditions (CH2Cl2/H2O) and tetra-n-butylammonium bromide as phase transfer agent under air at room temperature. Easy preparation, mild reaction conditions,
high yields of the products, short reaction times, no further oxidation to the corresponding carboxylic acids, high selectivity
and inexpensive reagents make this catalytic system a useful oxidation method for aliphatic and benzylic alcohols. 相似文献
57.
58.
Reza Karimi Shervedani Saied Mohsen Siadat‐Barzoki Mojtaba Bagherzadeh 《Electroanalysis》2010,22(9):969-977
A new sensor, gold‐6‐amino‐2‐mercaptobenzothiazole (6A2MBT), was fabricated via a self‐assembly procedure. Electrochemical properties of the monolayer were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The modified electrode showed excellent antifouling property against the oxidation products of DA, allowed us to construct a dynamic calibration curve with two linear parts, 1.00×10?6 to 3.72×10?4 and 3.72×10?4 to 6.42×10?4 M DA, with correlation coefficients of 0.997 and 0.992 and a detection limit of 1.57×10?7 M DA by using differential pulse voltammetry (DPV), respectively. Finally, the performance of the Au‐6A2MBT modified electrode was successfully tested for electrochemical detection of DA in a pharmaceutical sample. 相似文献
59.
Malek T. Maghsoodlou Nourallah Hazeri Sayed M. Habibi-Khorassani Reza Heydari Ghasem Marandi Mojtaba Lashkari Khatereh Bagherpour Zahra Gharechaei 《Monatshefte für Chemie / Chemical Monthly》2010,39(5):351-356
Abstract
Synthesis of five phosphonato esters has been accomplished via reaction between dimethyl acetylenedicarboxylate and triphenyl phosphite in the presence of biological compounds such as theophylline, 4-hydroxypyrimidine, 2H-3,1-benzoxazine-2,4(1H)-dione, 2-chloroaniline, or 3-nitroaniline at ambient temperature. The configuration of the compounds was determined on the basis of coupling constants emerging from the Karplus equation. 相似文献60.
A new method, based on the concepts of matrix analysis as well as the learning capabilities of neural networks, for the analysis of nonlinear trusses under dynamic loading is presented. The method can be applied to static trusses too. While there have been attempts in the past to use neural networks to identify and model different structures based on data measured on structural response directly, the main feature and advantage of this new method is in its capability to model a nonlinear truss by assembling the data collected on the response of its members. The basics of the method are: (1) for each truss member, a neural network is trained to learn and simulate its load-response behavior, (2) the member neural networks are then assembled to build another neural network which can simulate the load-response behavior of the whole truss. Noticing test at member level is generally easier than at structure level, this can make the building of a neural network to simulate the response of the truss more affordable. Also this has potential application when it is hard to find a mathematical model from experimental data to describe the internal force vector for a truss, as well as identification and control of trusses where precise modeling of the structure is a key point to the success of the application. Prandtl Neural Network, developed recently by the authors for modeling of nonlinear hysteretic materials, has been improved and used in this study too. The improved version has been called Prandtl-2 Neural Network (PNN2) in this paper. The method has been applied to the static and dynamic analysis of a 3-bar and a 10-bar benchmark truss successfully, the results of which are reported in this paper. 相似文献