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121.
Zahra Jafari Chermahini Alireza Najafi Chermahini Hossein A. Dabbagh Behzad Rezaei Neda Irannejad 《Journal of the Iranian Chemical Society》2017,14(7):1549-1556
Di(1H-tetrazol-5-yl)methane is employed as a new electron acceptor group in the synthesis of two metal-free organic dyes containing triphenylamine donor group. Dye-sensitized nanocrystalline TiO2 solar cell (DSSC) applying these novel dyes is constructed for consideration of their photovoltaic properties. The electronic properties of the dyes are also considered with the aid of theoretical calculations. The DSSC constructed from 4-(2,2-di(1H-tetrazol-5-yl)vinyl)-N,N-diphenylaniline (T1) shows a short-circuit photocurrent density of 13.38 mA cm?2, an open circuit voltage of 578 mV, and a fill factor of 0.54, with a resulted solar energy-to-electricity conversion efficiency of 4.18% under simulated 1 sun irradiation (100 mW cm?2). This result reveals that the dye with the di(1H-tetrazol-5-yl)methane anchoring group injects more electrons to the conduction band of TiO2 in comparison with its analogs with single tetrazole ring in their anchoring group. It is found that in spite of a red-shift of the absorption spectrum resulted from the lengthening of the molecule, the dye with two di(1H-tetrazol-5-yl)methane groups gives lower performance than the dye with a single electron acceptor. 相似文献
122.
A modified pseudospectral method for solving trajectory optimization problems with singular arc
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Zahra Foroozandeh Mostafa Shamsi Vadim Azhmyakov Masoud Shafiee 《Mathematical Methods in the Applied Sciences》2017,40(5):1783-1793
This paper presents a direct method based on Legendre–Radau pseudospectral method for efficient and accurate solution of a class of singular optimal control problems. In this scheme, based on a priori knowledge of control, the problem is transformed to a multidomain formulation, in which the switching points appear as unknown parameters. Then, by utilizing Legendre‐Radau pseudospectral method, a nonlinear programming problem is derived which can be solved by the well‐developed parameter optimization algorithms. The main advantages of the present method are its superior accuracy and ability to capture the switching times. Accuracy and performance of the proposed method are examined by means of some numerical experiments. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
123.
Screen-printing is one of the most promising approaches towards simple, rapid and inexpensive production of biosensors. Disposable biosensors based on screen printed electrodes (SPEs) including microelectrodes and modified electrodes have led to new possibilities in the detection and quantitation of biomolecules, pesticides, antigens, DNA, microorganisms and enzymes. SPE-based sensors are in tune with the growing need for performing rapid and accurate in-situ analyses and for the development of portable devices. This review (with 226 refs.) first gives an introduction into the topic and then is subdivided into sections (a) on DNA sensors (including methods for the detection of hybridization and damage), (b) on aptasensors (for thrombin, OTA, immunoglobulins and cancer biomarkers), (c) on immunosensors (for microorganisms, immunoglobulins, toxins, hormones, lactoferrin and biomarkers), (d) on enzymatic biosensors (for glucose, hydrogen peroxide, various pharmaceuticals, neurotransmitters, amino acids, NADH, enzyme based sensors). Figure
This review first gives an introduction into the topic of screen-printed electrodes for biosensing and is subdivided into sections (a) on DNA sensors, (b) on aptasensors, (c) on immunosensors, (d) on enzymatic biosensors. It contains 226 references 相似文献
124.
Seyedeh Fatemeh Hojati Behrooz Maleki Zahra Beykzadeh 《Monatshefte für Chemie / Chemical Monthly》2011,14(3):87-91
Abstract
A simple and highly efficient method for synthesis of benzoxazoles, benzimidazoles, and oxazolo[4,5-b]pyridines is described. Condensation of orthoesters with o-substituted anilines or 2-amino-3-hydroxypyridine was performed in the presence of catalytic amounts of commercially available, inexpensive, and moisture-stable 1,3-dibromo-5,5-dimethylhydantoin under solvent-free conditions. The corresponding heterocycles were obtained in good to excellent yields. The main advantages of the present procedure are mild reaction conditions, short reaction times, high yields of products, easy work-up, and absence of solvent. 相似文献125.
126.
Razieh FAZAELI Hamid ALIYAN Shadpour MALLAKPOUR Zahra RAFIEE Maryam BORDBAR 《催化学报》2011,32(4):582-588
A novel compound constructed from polyoxometalate (H3PW12O40,PW12) and poly(amidoamine) (PA) was prepared at room temperature in an aqueous solution by an impregnation method.A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by the reaction between chalcone and phenylhydrazine in the presence of the title compound,PW12/PA,in high yields.The structures of the compounds obtained were determined by IR and 1H NMR spectra. 相似文献
127.
The present study reports the development, validation and application of a new green liquid chromatographic method for the determination of glutathione (GSH) in vegetable samples. In this work we introduce—for the first time—ethyl propiolate (EP) as an advantageous post-column derivatization reagent for thiolic compounds. GSH (tR = 6.60 min) and N-acetylcysteine (NAC, internal standard) (tR = 11.80 min) were separated efficiently from matrix endogenous compounds by using a 100% aqueous mobile phase (0.1%, v/v CH3COOH in 1 mmol L−1 EDTA, QV = 0.5 mL min−1) and a Prevail® reversed phase column that offers the advantage of stable packing material in aqueous mobile phases. The parameters of the post-column reaction (pH, amount concentration of the reagent, flow rates, length of the reaction coil and temperature) were studied. The linear determination range for GSH was 1–200 μmol L−1 and the LOD was 0.1 μmol L−1 (S/N = 3). Total endogenous GSH was determined in broccoli, potato, asparagus and Brussels sprouts using the standards addition approach. The accuracy was evaluated by both recovery experiments (R = 91–110%) and comparison to an o-phthalaldehyde/glycine corroborative post-column derivatization fluorimetric method. 相似文献
128.
Arash Ghorbani-Choghamarani Hamid Goudarziafshar Mohsen Nikoorazm Zahra Naseri 《中国化学快报》2011,22(12):1431-1434
A mixture of guanidinium nitrate and silica sulfuric acid acts as mild and heterogeneous media for the efficient mono nitration of phenolic compounds in dichloromethane at room temperature. 相似文献
129.
Zahra Shariatinia Mauricio F. Erben Carlos O. Della Védova Majid Abdous Saman Azodi 《Structural chemistry》2011,22(6):1347-1352
Intermolecular interactions between α-, β-glucose, and methacrylic acid (MAA) have been investigated. Twenty-two possible
conformations have been optimized at the DFT(B3LYP) level of theory with the 6-31G(d) basis set. The geometrical parameters
for the most stable configurations of hydrogen bonding sites in the optimized systems have been determined. The binding energies
ΔE
bind have been calculated at the MP2/6-311++G(d,p) level of approximation taking into account the basis set superposition error
(BSSE) and the zero-point vibrational energies corrections. Results indicate that the most stabilized complexes form hydrogen
bonds either through carboxylic and hemiacetal oxygen atoms acting as proton acceptors. Both, α- and β-anomers are studied
in the pyranose six-membered ring. In all complexes, the nuclear quadrupole coupling constants (χ) for 17O nuclei were obtained about 10.0 MHz, while for the 2H atoms they vary from ≈200.0 to ≈350.0 kHz. 相似文献
130.
Jalilehvand F Amini Z Parmar K Kang EY 《Dalton transactions (Cambridge, England : 2003)》2011,40(47):12771-12778
The complex formation between Cd(II) ions and N-acetylcysteine (H(2)NAC) in aqueous solution was investigated using Cd K- and L(3)-edge X-ray absorption and (113)Cd NMR spectroscopic techniques. Two series of 0.1 M Cd(II) solutions with the total N-acetylcysteine concentration c(H2NAC) varied between 0.2-2 M were studied at pH 7.5 and 11.0, respectively. At pH = 11 a novel mononuclear [Cd(NAC)(4)](6-) complex with the average Cd-S distance 2.53(2) ? and the chemical shift δ((113)Cd) = 677 ppm was found to dominate at a concentration of the free deprotonated ligand [NAC(2-)] > 0.1 M, consistent with our previous reports on cadmium tetrathiolate complex formation with cysteine and glutathione. At pH 7.5 much higher ligand excess ([HNAC(-)] > 0.6 M) is required to make this tetrathiolate complex the major species. The (113)Cd NMR spectrum of a solution containing c(Cd(II)) = 0.5 M and c(H2NAC) = 1.0 M measured at 288 K showed three broad signals at 421, 583 and 642 ppm, which can be attributed to CdS(3)O(3), CdS(3)O and CdS(4) coordination sites, respectively, in oligomeric Cd(II)-NAC species with single thiolate bridges between the cadmium ions. 相似文献