排序方式: 共有52条查询结果,搜索用时 15 毫秒
41.
B. Jaleh S. Mohammadtaheri N. Shahbazi S. Azizian 《International Journal of Polymer Analysis and Characterization》2015,20(8):733-742
In this work, polycarbonate-TiO2 nanocomposite films were prepared with different percentages. The aim was to consider the effect of O2 LF plasma (50 Hz) on the hydrophilicity, surface energy, and surface morphology of polycarbonate and polycarbonate-TiO2 nanocomposite. Structure of samples was determined by using X-ray diffraction analysis. In comparison with the reference sample, the samples’ structure did not change after plasma treatment. Surface properties of polycarbonate and polycarbonate-TiO2 nanocomposite films were studied by X-ray photoelectron spectroscopy (XPS), contact angle measurement, atomic force microscopy (AFM), and Vickers microhardness tester. XPS analysis showed that the surface of samples became more oxidized due to plasma treatment. The water contact angle significantly decreased from 88° to 15° after plasma treatment. It was observed that the hardness of the nanocomposite films was not modified after plasma treatment. 相似文献
42.
Copolymers are among the most promising substances used in the preparation of drug/gene delivery systems. Different categories of copolymers, including block copolymers, graft copolymers, star copolymers and crosslinked copolymers, are of interest in drug delivery. A variety of nanostructures, including polymeric micelles, polymersomes and hydrogels, have been prepared from copolymers and tested successfully for their drug delivery potential. The most recent area of interest in this field is smart nanostructures, which benefit from the stimuli-responsive properties of copolymeric moieties to achieve novel targeted drug delivery systems. Different copolymer applications in drug/gene delivery using nanotechnology-based approaches with particular emphasis on smart nanoparticles are reviewed. 相似文献
43.
Mixed‐Halide CH3NH3PbI3−xXx (X=Cl,Br, I) Perovskites: Vapor‐Assisted Solution Deposition and Application as Solar Cell Absorbers
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Rahime Sedighi Dr. Fariba Tajabadi Saeed Shahbazi Somayeh Gholipour Dr. Nima Taghavinia 《Chemphyschem》2016,17(15):2382-2388
There have been recent reports on the formation of single‐halide perovskites, CH3NH3PbX3 (X=Cl, Br, I), by means of vapor‐assisted solution processing. Herein, the successful formation of mixed‐halide perovskites (CH3NH3PbI3?xXx) by means of a vapor‐assisted solution method at ambient atmosphere is reported. The perovskite films are synthesized by exposing PbI2 film to CH3NH3X (X=I, Br, or Cl) vapor. The prepared perovskite films have uniform surfaces with good coverage, as confirmed by SEM images. The inclusion of chlorine and bromine into the structure leads to a lower temperature and shorter reaction time for optimum perovskite film formation. In the case of CH3NH3PbI3?xClx, the optimum reaction temperature is reduced to 100 °C, and the resulting phases are CH3NH3PbI3 (with trace Cl) and CH3NH3PbCl3 with a ratio of about 2:1. In the case of CH3NH3PbI3?xBrx, single‐phase CH3NH3PbI2Br is formed in a considerably shorter reaction time than that of CH3NH3PbI3. The mesostructured perovskite solar cells based on CH3NH3PbI3 films show the best optimal power conversion efficiency of 13.5 %, whereas for CH3NH3PbI3?xClx and CH3NH3PbI3?xBrx the best recorded efficiencies are 11.6 and 10.5 %, respectively. 相似文献
44.
J. Shahbazi Mojarrad H. Nazemiyeh F. Kaviani 《Journal of the Iranian Chemical Society》2010,7(1):171-179
Most of the known effects of angiotensin II are mediated via AT1 receptor by increasing intracellular Ca2+ by influx of extracellular Ca2+. Combination therapies of angiotensin receptor blocker (ARB) with calcium channel blocker (CCB) which act through L-type calcium channel have beneficial therapeutic and protective effects on cardiovascular system. Thus, it was hypothesized that merging the key structural elements present in an AT1 receptor antagonist (telmisartan) with key structural elements in 1,4-dihydropyridine calcium channel blockers (nifedipine) would yield a compound with dual activity for both receptors. This strategy led to the design and synthesis of dialkyl 1,4-dihydro-2,6-dimethyl-4-[2-n-alkyl-1-[(2′-carboxybiphenyl- 4-yl)methyl]imidazole-4(or 5)-yl]-3,5-pyridinedicarboxylates (4 and 6). The synthesis of compounds 4 and 6 was accomplished through the reaction of 2-n-alkyl-1-[(2′-carbomethoxybiphenyl-4-yl)methyl]imidazole-4(or 5)-carboxaldehydes with alkyl acetoacetate followed by regioselctive hydrolysis of carboethoxybiopheny to carboxybiphenyl that are essential for ARB activity. It is suggested that existence of hindrance by substituted groups prevent hydrolysis of esteric groups on dihydropyridine ring. The structures of the compounds were characterized by 1H-nuclear magnetic resonance, infrared and mass spectroscopy. 相似文献
45.
46.
Theoretical calculation and prediction for experimental design to obtain spin crossover complexes
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Farsheed Shahbazi‐Raz Maryam Adineh Nasser Safari Mansour Zahedi 《International journal of quantum chemistry》2016,116(15):1179-1186
DFT methods were utilized to study SCO complexes. [Fe(2btz)2(NCX)2] (2btz = 2,2′‐bithiazoline, X = S ( 1 ) and Se ( 2 )), [Fe(phen)2(NCX)2] (phen = 1,10‐phenantroline, X = S ( 3 ) and Se ( 4 )), and [Fe(bpy)2(NCS)2] ( 5 ) (bpy = 2,2′‐bipyridine) compounds, which have experimentally shown SCO behavior, were calculated. B3LYP, B3LYP*, OPBE, and OLYP with 6‐31G* and 6‐311 + G** basis sets were employed to calculate the ΔEHS/LS energy gap as a clue to find complexes with SCO behavior. It is found that calculated result by B3LYP* with c3 = 0.14 and OPBE methods and 6‐31G* basis set are in agreement with experimentally observed SCO complexes. Then, newly designed Fe(N‐N)2(X)2 complexes, where N‐N are bidentate nitrogen donor chelating ligands and X= SCN‐, SeCN‐, Cl‐, Br‐, I‐, were chosen to see their potential to be SCO compounds. ΔEHS/LS for potential SCO complexes are estimated from 0.8 to 6.5 kcal/mol in B3LYP* and 0.6–5.7 kcal/mol in OPBE. These calculations suggest [Fe(bpy)2(NCSe)2], [Fe(5dmbpy)2(NCS)2], and [Fe(3‐BrPhen)2(NCSe)2] compounds have the ability to show SCO behavior. © 2016 Wiley Periodicals, Inc. 相似文献
47.
The separation of lactic acid from lactose in the ultrafiltration permeate of cheese whey broth was studied using a cross-flow
nanofiltration membrane unit. Experiments to test lactic acid recovery were conducted at three levels of pressure (1.4, 2.1,
and 2.8 MPa), two levels of initial lactic acid concentration (18.6 and 27 g/L), and two types of nanofiltration membranes
(DS-5DK and DS-5HL). Higher pressure caused significantly higher permeate flux and higher lactose and lactic acid retention
(p<0.0001). Higher initial lactic acid concentrations also caused significantly higher permeate flux, but significantly lower
lactose and lactic acid retention (p<0.0001). The two tested membranes demonstrated significant differences on the permeate flux and lactose and lactic acid retention.
Membrane DS-5DK was found to retain 100% of lactose at an initial lactic acid concentration of 18.6 g/L for all the tested
pressures, and had a retention level of 99.5% of lactose at initial lactic acid concentration of 27 g/L when the pressure
reached 2.8 MPa. For all the test when lactose retention reached 99–100%, as much as 64% of the lactic acid could be recovered
in the permeate. 相似文献
48.
Amir Akbari Sarah Maghsoodi Amirhossein Shahbazi Kootenaei 《Journal of Dispersion Science and Technology》2019,40(1):17-24
This research aimed to evaluate the thermal viscosity, stability, conductivity and density of coolants including PEG-functionalized graphene nanoplatelets (GNPs) and gum Arabic (GA)-treated GNPs as a base fluid at various temperatures and concentrations. The present study explores the impacts of GNPs functionalized with poly ethylene glycol (PEG) on the colloidal stability and thermophysical properties of water-based PEG-functionalized GNPs suspensions as a new generation of heat transfer fluids. To this end, PEG-functionalized GNPs as a covalent sample and GA-treated GNPs were synthesized and their colloidal stabilities were traced via UV–vis spectrometry. After functionalized, colloidal stability results indicate less sedimentation for covalent samples (less than 10%) that that of noncovalent one (almost 20%) after a 15-day period. In addition, all the thermophysical properties e.g. thermal conductivity, density and viscosity were measured experimentally. Further, it has shown that by loading PEG-functionalized GNPs in the water, the increasing rate of the density and viscosity is not significant, while water-based GA-treated GNPs nanofluids showed higher rates of increase. Interestingly, the water-based PEG-functionalized GNP nanofluids at very low concentration significantly increase the thermal conductivity in comparison with that of non-covalent nanofluid at the same concentration and temperature and defiantly water. 相似文献
49.
Semicontinuous production of lactic acid from cheese whey using free cells of Bifidobacterium longum with and without nanofiltration was studied. For the semicontinuous fermentation without membrane separation, the lactic acid productivity of the second and third runs is much lower than the first run. The semicontinuous fermentation with nanoseparation was run semicontinuously for 72 h with lactic acid to be harvested every 24 h using a nanofiltration membrane unit. The cells and unutilized lactose were kept in the reactor and mixed with newly added cheese whey in the subsequent runs. Slight increase in the lactic acid productivity was observed in the second and third runs during the semicontinuous fermentation with nanofiltration. It can be concluded that nanoseparation could improve the lactic acid productivity of the semicontinuous fermentation process. 相似文献
50.
The combination of aromatic aldehydes, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS] and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide [TBBDA] leads to the formation of highly substituted tetrahydropyridines. In this way, a series of pharmacologically interesting substituted piperidine derivatives were obtained in moderate to high yields at room temperature. 相似文献