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排序方式: 共有250条查询结果,搜索用时 23 毫秒
71.
Yan Shu-Rong Kalbasi Rasool Karimipour Aliakbar Afrand Masoud 《Journal of Thermal Analysis and Calorimetry》2021,145(5):2809-2816
Journal of Thermal Analysis and Calorimetry - In this study, the efficacy of adding nanoparticles of MWCNTs to the base fluid of paraffin on the thermal conductivity has been investigated.... 相似文献
72.
Rostami Sara Toghraie Davood Shabani Behrooz Sina Nima Barnoon Pouya 《Journal of Thermal Analysis and Calorimetry》2021,143(2):1097-1105
Journal of Thermal Analysis and Calorimetry - In this paper, artificial neural networks (ANNs) are developed to predict the thermal conductivity ( $$k_{\text{nf}}$$ ) of multi-walled carbon... 相似文献
73.
Elaheh Nourbala Tafti Ali Mohammad Haji Shabani 《International journal of environmental analytical chemistry》2017,97(5):444-455
A simple, sensitive and reliable method has been developed for separation and preconcentration of chromium (VI) from aqueous samples before determination by electrothermal atomic absorption spectrometry. The method is based on the extraction of the hydrophobic complex of chromium (VI) with ammonium pyrrolidine dithiocarbamate in the coacervates made up of decanoic acid reverse micelles in the water–tetrahydrofuran mixture. Parameters affecting the extraction efficiency of the analyte were studied and optimised. Under the optimum conditions, the linear range, enhancement factor, the limit of detection and limit of quantification were found to be 0.008–0.4 µg L?1, 127, and 1.8 ng L?1 and 6.0 ng L?1, of Cr(VI), respectively. The relative standard deviation at the concentration level of 0.1 µg L?1 Cr(VI) (n = 6) was 4.2%. Total chromium was determined after the oxidation of Cr(III) to Cr(VI) with permanganate in acidic medium. The method was successfully applied to the determination of chromium species in water and human serum samples. 相似文献
74.
Elahe Kazemi Ali Mohammad Haji Shabani Parisa Sadat Hashemi 《International journal of environmental analytical chemistry》2017,97(8):743-755
This study describes the successful sequential modification of multi-walled carbon nanotube (MWCNT) by Fe3O4 magnetic nanoparticles and 2-mercaptobenzothiazole (MBT) followed by its application as a novel sorbent for simultaneous magnetic solid phase microextraction of lead and cadmium. Fourier transform infrared spectroscopy and scanning electron microscopy were employed to confirm the chemical surface modification of the MWCNT. The ions retained on the 2-MBT/magnetic nanoparticles modified MWCNTs were eluted with 1.0 mL of nitric acid (0.8 mol L?1) in methanol solution and determined by the flame atomic absorption spectrometry. All parameters affecting the extraction condition were thoroughly investigated and optimised. Under the optimised condition preconcentration factor of 150.0, enhancement factors of 149.0 and 149.2 and limits of detection of 0.21 and 0.01 µg L?1 were achieved for lead and cadmium, respectively. Using the prepared magnetic nanocomposite, the possible interference of other common ions associated with lead and cadmium determination was effectively avoided and the method was successfully applied to the simultaneous determination of the target ions in various environmental water samples. 相似文献
75.
Mohammad Mirak Morteza Alizadeh Erfan Salahinejad Rasool Amini 《Surface and interface analysis : SIA》2015,47(2):176-183
In this work, zinc–hydroxyapatite (Zn–HA) and zinc–hydroxyapatite–titania (Zn–HA–TiO2) nanocomposite coatings were electrodeposited onto a NiTi shape memory alloy, using a chloride zinc plating bath. The structure of the composite coatings was characterized by X‐ray diffraction, scanning electron microscopy and high‐resolution transmission electron microscopy. According to the results, the Zn–HA–TiO2 coating exhibited a plate‐like surface morphology, where the addition of the nanoparticles caused to an increase in roughness. It was also found that due to applying a proper stirring procedure during co‐deposition, a homogenous dispersion of the nanoparticles in the coatings was achieved. Also, the addition of the TiO2 nanoparticles to the Zn–HA–TiO2 coating enhanced the microhardness and wear resistance. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
76.
活性炭负载硫化锡纳米颗粒作为高效可重复使用Lewis酸催化剂催化三组分一锅法合成4H-吡喃[2,3-c]吡唑衍生物(英文) 总被引:1,自引:0,他引:1
Tin sulfide nanoparticles(SnS -NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon(AC) and were investigated using field-emission scanning electron mi-croscopy(FE-SEM), transmission electron microscopy(TEM), X-ray diffraction, reflective ultravio-let-visible spectrophotometry, and spectrofluorimetry. Calculations based on the SEM and TEM images showed that the sizes of the SnS -NPs immobilized on the AC were 30–70 nm. The prepared nanocomposite was used as a heterogeneous Lewis acid catalyst for the three-components one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol at 80 ℃. The reactions were efficiently performed in the presence of the prepared catalyst in short reaction times, and gave the desired products in high yields. This catalyst can be easily recovered by simple filtration and recycled up to eight consecutive times without significant loss of its efficiency. 相似文献
77.
The effect of temperature and slice thickness on drying kinetics tomato in the infrared dryer 总被引:1,自引:0,他引:1
In this study thin layer drying of tomato slices were investigated in the infrared dryer. Drying rate increased with increasing temperature and reduction thickness and thus reduced the drying time. The effective diffusivity increased with increasing temperature and with increasing thickness of the samples. The effective diffusivity values changed from 1.094 × 10?9 to 4.468 × 10?9 m2/s and for activation energy varied from 110 to 120 kJ/mol. The best model for drying process of tomato slices was Midilli model. 相似文献
78.
Fundamental Study of Pore Scale Mechanisms in Microbial Improved Oil Recovery Processes 总被引:1,自引:0,他引:1
A fundamental study of microscopic mechanisms and pore-level phenomena in the Microbial Improved Oil Recovery method has been
investigated. Understanding active mechanisms to increase oil recovery is the key to predict and plan MIOR projects successfully.
This article presents the results of visualization experiments carried out in a transparent pore network model. In order to
study the pore scale behavior of bacteria, dodecane and an alkane oxidizing bacterium, Rhodococcus sp. 094, suspended in brine, are examined for evaluating the performance of bacterial flooding in the glass micromodel. The
observations show the effects of bacteria on remaining oil saturation, allowing us to get better insight on the mechanisms.
Bacterial mass composed of bacteria and bioproducts growth in the fluid interfaces and pore walls have been recorded and are
presented. No gas is observed throughout any of the experiments. The biomass blocks some pores and pore-throats, and thereby
changing the flow pattern. As a consequent, the flow pattern change together with the previously proposed mechanisms, including
the interfacial tension reduction and wettability changes are recognized as active mechanisms in the MIOR process. 相似文献
79.
2, 3-Dihydroquinazolin-4 (1H)-ones have been synthesized in the high to excellent yields via condensation of 2-aminobenzamide with aldehydes and ketones in the presence of catalytic amount of ZrCl4 in EtOH at room temperature. Mild reaction conditions, clean reaction media, simple workup and easy purification are advantages of this methodology. 相似文献
80.
Abdul Malik Nighat Afza Shazia Yasmeen Mohammad Aijaz Anwer Muhammad Irfan Ali Rasool Bakhsh Tareen 《Helvetica chimica acta》2011,94(1):163-168
Hertidins A–E ( 1 – 5 , resp.), new eremophilenolide‐type sesquiterpenes, have been isolated from the AcOEt‐soluble fraction of Hertia intermedia. Structures of 1 – 5 were elucidated on the basis of extensive spectroscopic studies. 相似文献