排序方式: 共有63条查询结果,搜索用时 31 毫秒
51.
Shadlaghani Arash Farzaneh Mahsa Shahabadi Mohammad Tavakoli Mohammad Reza Safaei Mohammad Reza Mazinani Iman 《Journal of Thermal Analysis and Calorimetry》2019,135(2):1429-1442
Journal of Thermal Analysis and Calorimetry - In this paper, the effect of internal serrated fins and eccentricity on natural convection heat transfer between annular spaces with the equivalent... 相似文献
52.
Majid Moghadam Iraj Mohammadpoor‐Baltork Shahram Tangestaninejad Valiollah Mirkhani Parvin Yazdani Saeedeh Ghorjipoor 《Heteroatom Chemistry》2009,20(3):131-135
Various types of aromatic aldehydes were efficiently converted to their corresponding 1,3‐dioxanes and 1,3‐dioxolane with 1,3‐propanediol and ethylene glycol, respectively, in the presence of catalytic amount of ZrO(OTf)2 in acetonitrile at room temperature. The catalyst can be reused several times without loss of its catalytic activity. Very short reaction times, selective acetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones, very mild reaction conditions, reusability of the catalyst, and easy workup are noteworthy advantages of this method. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:131–135, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20523 相似文献
53.
Mohammad Abbasi Najmeh Nowrouzi Saeedeh Ghassab Borazjani 《Tetrahedron letters》2017,58(45):4251-4254
A sulfur transfer reagent was produced in situ upon stirring a mixture of KCN and CS2 in DMF at r.t. for 15 min, which after heating with an alkyl halide or aryl halide and CuI gave the corresponding symmetric dialkyl or diaryl disulfide, respectively, in high to excellent yields. 相似文献
54.
Javad Safari Soheila Gandomi-Ravandi Saeedeh Shariat 《Journal of the Iranian Chemical Society》2016,13(8):1499-1507
In the present investigation, we have developed a novel technique to prepare azines using nano-WCl6 loaded on Montmorillonite K10 clay as a highly active catalyst. A variety of aldehydes and ketones were efficiently converted to the corresponding azines using catalytic amounts of nanosized WCl6/Mont. K10 under mild conditions. The nanostructures of WCl6 loaded on Mont. K10 as solid acid catalyst have been prepared by solid dispersion method. The advantages of this catalyst are rapid completion of the reactions, simplicity of performance, lack of pollution and mild and green reaction conditions. The morphologies, structure, and chemical components of parent and modified clay were successfully characterized using SEM, FT-IR, CV, XRD and EDX measurements. 相似文献
55.
In the present study, the adsorption and decomposition of diazomethane (DAZM) on the surface of (6,0) zigzag silicon carbide nanotube (SiCNT) are investigated using density functional theory calculations. The geometry structures of the three stable configurations, adsorption energies and electronic properties of DAZM adsorption on the surface of SiCNT are investigated. It was found that the DAZM molecule is decomposed over the surface of (6,0) SiCNT with activation energy (Eact) of 0.523 eV. The curvature effect on the adsorption energies of the DAZM molecule is also considered by studying (5,0) and (7,0) SiCNTs. The results display that DAZM adsorption over smaller diameter of SiCNT is thermodynamically more favourable than larger one. 相似文献
56.
57.
Suhaina Mohd Ibrahim Abdul Kadir Masrom Babak Mazinani Shahidan Radiman Farinaa Md Jamil Ali Beitollahi Nobuaki Negishi Noorhana Yahya 《Research on Chemical Intermediates》2013,39(3):1003-1014
Mesoporous TiO2 has been synthesized by the sol–gel method, using a nonionic triblock copolymer P123 as surfactant template under acidic conditions. The as-prepared samples were characterized by thermogravimetry–differential thermal analysis (TG–DTA), nitrogen absorption–desorption (BET), field emission scanning electron microscopy, and transmission electron microscopy. The photocatalytic activity of the mesoporous TiO2 was evaluated by degradation of methylene blue under high-intensity UV light irradiation; the amount of methylene blue was measured by UV–visible spectroscopy. TG–DTA analysis revealed that the surfactant had been removed partly in as-synthesized samples. BET analysis proved that all the samples retained mesoporosity with a narrow pore-size distribution (4.5–6.3 nm) and high surface area (103–200 m2/g). All calcined mesoporous TiO2 had high photocatalytic activity in the photodegradation of methylene blue. 相似文献
58.
Navid Amini Saeedeh Mazinani Seyed-Omid Ranaei-Siadat Mohammad Reza Kalaee Saeed Hormozi Kaveh Niknam Nasrin Firouzian 《Applied biochemistry and biotechnology》2013,170(1):91-104
In this work, polyacrylamide/multi-walled carbon nanotubes (MWCNT) solution is electrospun to nanocomposite nanofibrous membranes for acetylcholinesterase enzyme immobilization. A new method for enzyme immobilization is proposed, and the results of analysis show successful covalent bonding of enzymes on electrospun membrane surface besides their non-covalent entrapment. Fourier transform infrared spectroscopy, mechanical and thermal investigations of nanofibrous membrane approve successful cross-linking and enzyme immobilization. The enzyme relative activity and kinetic on both pure and nanocomposite membranes is investigated, and the results show proper performance of designed membrane to even improve the enzyme activity followed by immobilization compared to free enzyme. Scanning electron microscopy images show nanofibrous web of 3D structure with a low shrinkage and hydrogel structure followed by enzyme immobilization and cross-linking. Moreover, the important role of functionalized carbon nanotubes on final nanofibrous membrane functionality as a media for enzyme immobilization is investigated. The results show that MWCNT could act effectively for enzyme immobilization improvement via both physical (enhanced fibers’ morphology and conductivity) and chemical (enzyme entrapment) methods. Figure
Mechanism for APTS surface modification of nanofibrous nanoweb for enzyme immobilization 相似文献
59.
A suite of branched-chain pyrogallol[4]arene (Pg) macrocycles, most of which show activity in bilayer membranes, has been prepared and studied by X-ray crystallography. The little-known branched side-chain Pgs include 2-propyl, 2-butyl, 2-pentyl, 3-pentyl, 3-heptyl, 4-heptyl, 5-nonyl and cyclohexyl. The Pgs form self-assembled structures having bilayer, capsule or, in one case, a nanotube morphology. The nanotube structure observed for C-(di-n-ethyl)pyrogallol[4]arene was confirmed by X-ray structure analysis and by transmission and scanning electron microscopies. 相似文献
60.
Babak Mazinani Ali Beitollahi Abdul Kadir Masrom Noorhana Yahya Thomas S. Y. Choong Suhaina Mohd Ibrahim Jafar Javadpour 《Research on Chemical Intermediates》2012,38(8):1733-1742
TiO2?CSiO2 mesoporous materials were synthesised by deposition of TiO2 nanoparticles prepared by the sol?Cgel method on to the internal pore surface of wormhole-like mesoporous silica. In this work we synthesised wormhole-like mesoporous silica of different surface area by changing the hydrothermal temperature (70, 100, or 130?°C). Subsequent to this, titania solution was deposited on to the inner surface of the pores and this was followed by calcination at different temperatures (400, 600, or 800?°C). The effect of different hydrothermal and calcination temperature on the photocatalytic properties was evaluated. The samples were characterized by N2-sorption, X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The effect of different hydrothermal and calcination temperatures on the photocatalytic properties was evaluated by measuring the degradation of methylene blue in aqueous solution under UV light irradiation (mercury lamp, 125?W). The results indicated that appropriate surface area and degree of crystallinity are two important factors for obtaining high photocatalytic efficiency. Samples prepared at a hydrothermal temperature of 100?°C and calcined at 800?°C had the best photocatalytic performance, because of the highest surface area and high crystallinity. 相似文献