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101.
K. Jalaiah K. Vijaya Babu K. Rajasekhar Babu V. Venkat Kumar R.V. Krishnaiah 《Chinese Journal of Physics (Taipei)》2018,56(5):2039-2051
The zirconium and copper co-substituted Ni0.75Zn0.25ZrxCuxFe2-2xO4 (where x?=?0.05, 0.1, 0.15, 0.2) ferrites have been prepared by sol-gel auto-combustion method. The XRD patterns provide the evidence of single phase cubic spinel structure. The theoretical and experimental lattice parameters have resemblance with increase dopant concentration. The sintered density and porosity show the opposite trend with dopant concentration. The FT-IR spectrum of prepared samples reveal cubic spinel with () space group. The wave numbers of tetrahedral and octahedral sites show agnate trend. The dielectric constant and loss factors decreased with increasing dopant concentration. The saturation magnetization and net magnetic moment have the identical trend with increasing dopant concentration. The coercive field is decreased with increasing dopant concentration. The Y–K angles are increased with increasing dopant concentration. The Q-factor in prepared samples, exhibit narrower frequency bands with increasing frequency. 相似文献
102.
Plasma-assisted functional films have significant potential in various engineering applications. They can be tailored to impart desired properties by bonding specific molecular groups to the substrate surface. The aim of this investigation was to develop a fundamental understanding of the atomic level growth, coverage and functional effectiveness of plasma nano-films on flat surfaces and to explore their application-potential for complex and uneven shaped nano-materials. In this paper, results on plasma-assisted nano-scale fluorocarbon films, which are known for imparting inertness or hydrophobicity to the surface, will be discussed. The film deposition was studied as a function of time on flat single crystal surfaces of silicon, sapphire and graphite, using microwave plasma. X-ray photoelectron spectroscopy (XPS) was used for detailed study of composition and chemistry of the substrate and coating atoms, at all stages of deposition. Atomic force microscopy (AFM) was performed in parallel to study the coverage and growth morphology of these films at each stage. Combined XPS and AFM results indicated complete coverage of all the substrates at the nanometer scale. It was also shown that these films grew in a layer-by-layer fashion. The nano-films were also applied to complex and uneven shaped nano-structured and porous materials, such as microcellular porous foam and nano fibers. It was seen that these nano-films can be a viable approach for effective surface modification of complex or uneven shaped nano-materials. 相似文献
103.
A cloud point extraction method has been developed using an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, BMiM PF(6)) for the determination of a widely studied cyanotoxin (microcystin leucine-arginine, MCLR) in natural waters. Extraction parameters such as sample pH, extraction temperature, extraction time, the amount of ionic liquid and the amount of extraction volume were investigated and optimized to achieve the maximum extraction efficiency. The results obtained indicated a good linearity with the correlation coefficient of 0.995 over the range of 0.5-50 μg L(-1). The relative standard deviation (RSD) of the method was 7.5% (n=6). The calculated method detection limit was 0.03 μg L(-1) (n=6). The practical applicability of the technique was demonstrated by analyzing water samples (n=9) collected from three different sites in local reservoirs. 相似文献
104.
Pilli NR Inamadugu JK Kondreddy N Karra VK Damaramadugu R Rao JV 《Biomedical chromatography : BMC》2011,25(8):943-951
A rapid and sensitive liquid chromatography–tandem mass spectrometric (LC‐MS/MS) assay method has been developed and fully validated for simultaneous quantification of donepezil and its active metabolite, 6‐o‐desmethyl donepezil in human plasma. Analytes and the internal standard were extracted from human plasma by liquid–liquid extraction technique using a 30:70 v/v mixture of ethyl acetate and n‐hexane. The reconstituted samples were chromatographed on a C18 column by using a 70:30 v/v mixture of acetonitrile and ammonium formate (5 mm , pH 5.0) as the mobile phase at a flow rate of 0.6 mL/min. The calibration curve obtained was linear (r ≥ 0.99) over the concentration range of 0.09–24.2 ng/mL for donepezil and 0.03–8.13 ng/mL for 6‐o‐desmethyl donepezil. The results of the intra‐day and inter‐day precision and accuracy studies were well within the acceptable limits. The proposed method was successfully applied for the estimation of the drug in real time plasma samples for pharmacokinetic studies. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
105.
Padmaja A Muralikrishna A Rajasekhar C Padmavathi V 《Chemical & pharmaceutical bulletin》2011,59(12):1509-1517
A new class of pyrrolyl/pyrazolyl arylaminosulfonylmethyl 1,3,4-oxadiazoles, 1,3,4-thiadiazoles, and 1,2,4-triazoles were prepared and tested for antimicrobial activity. Amongst the tested compounds, 5c displayed high antimicrobial activity. 相似文献
106.
Subba Rao Devineni Srinivasulu Doddaga Rajasekhar Donka Naga Raju Chamarthi 《中国化学快报》2013,24(8):759-763
CeCl3·7H2O supported on silica(CeCl3·7H2O-SiO2) is used as a heterogeneous,efficient and recyclable catalyst for a three component one-pot reaction of an amine,aldehydes and diethyl phosphite to synthesizeα-diaminophosphonate derivatives under microwave irradiation exploiting neat reaction conditions.Tenα-diaminophosphonates(6a-j) of 4,4’-sulfonyldianiline(Dapsone)(3) were synthesized and structural elucidation was confirmed by spectral data.Antifungal and antioxidant activities were evaluated include minimum inhibitory concentrations and IC50 values,respectively of the titled compounds.Compounds 6h,6i exhibited promising antioxidant activity at lower IC50 values 53.7μg/mL, 53.2μg/mL,respectively as compared with standard IC50 value 51.6μg/mL. 相似文献
107.
M. Varalakshmi D. Srinivasulu D. Rajasekhar C. Naga Raju S. Sreevani 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):106-112
Abstract A new class of diethyl(3,5-dibromo-4-hydroxyphenylamino) (substituted phenyl/heterocyclic) methylphosphonates 4(a–j) has been synthesized by one-pot three component simultaneous reaction (Kabachnik–Fields) of 4-amino-2,6-dibromophenol 1, substituted heterocyclic/phenyl aldehydes 2(a–j), and diethylphosphite 3 using a Lewis acid catalyst, CeCl3·7H2O (5 mol%) under microwave irradiation as well as conventional conditions. It was observed that microwave irradiation method is more facile, efficient, and advantageous with respect to reaction time and yields. The structures of all the synthesized compounds were supported by analyzing IR, 1H/13C/31P NMR, and mass spectral data. The synthesized compounds were screened for their in vitro antimicrobial and antioxidant activities. 相似文献
108.
Abdallah A. Shaltout Maram M. Dabi Doaa A. Said Mousa A. Allam Sameh I. Ahmed 《X射线光谱测定》2022,51(3):214-229
Low calcium oxalate urinary stones from the kidney, bladder, and ureter have been collected from the arid area (Taif, Saudi Arabia). After careful washing and drying of the collected stones, the samples were converted into a contamination-free homogenous fine powder with a particles' size smaller than 50 μm. The processed urinary stone powders were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), laboratory setup and synchrotron radiation X-ray diffraction (XRD), and energy-dispersive X-ray fluorescence (EDXRF). The activated function groups, quantitative phase analysis, and the semi-quantitative elemental analysis of the present urinary stones were identified. Seventeen elements were measured in most of the urinary stone samples. The significant elements are Ca, P, S, Cl, Zn, K, Fe, and Cu, whereas other elements were found alternatively in a few number of urinary stone samples. It was recognized that Ca exists with low concentration, which indicates the presence of different calcium phases even with low percentages. In 33% of the urinary stones, the phosphorus (P) was not measured, but there were high concentrations of sulfur (S) and low concentrations of Ca up to 2.15 ± 0.05%. The ATR-FTIR results indicate that the most compounds of the present urinary stones were urea and cystine combined with low ratios of calcium oxalate and calcium phosphate compounds. The quantitative phase analysis of the XRD of selected samples proves the presence of the cystine, urea, and calcium oxalate phases with different weight percent. 相似文献
109.
Chittoor Rajasekhar Suram Durgamma Adivireddy Padmaja 《Journal of heterocyclic chemistry》2014,51(6):1727-1734
A new class of pyrazolyl/isoxazolyl‐oxazolines and thiazolines was synthesized from simple substrate E‐aroylethenesulfonylacetic acid methyl ester with the aid of the samarium(III) chloride catalyst and 1,3‐dipolar cycloaddition methodology. 相似文献
110.
Recent advances in the use of graphene-family nanoadsorbents for removal of toxic pollutants from wastewater 总被引:1,自引:0,他引:1
Adsorption technology is widely considered as the most promising and robust method of purifying water at low cost and with high-efficiency. Carbon-based materials have been extensively explored for adsorption applications because of their good chemical stability, structural diversity, low density, and suitability for large scale production. Graphene – a single atomic layer of graphite – is the newest member in the family of carbon allotropes and has emerged as the “celeb” material of the 21st century. Since its discovery in 2004 by Novoselov, Geim and co-workers, graphene has attracted increased attention in a wide range of applications due to its unprecedented electrical, mechanical, thermal, optical and transport properties. Graphene's infinitely high surface-to-volume ratio has resulted in a large number of investigations to study its application as a potential adsorbent for water purification. More recently, other graphene related materials such as graphene oxide, reduced graphene oxide, and few-layered graphene oxide sheets, as well as nanocomposites of graphene materials have also emerged as a promising group of adsorbent for the removal of various environmental pollutants from waste effluents. In this review article, we present a synthesis of the current knowledge available on this broad and versatile family of graphene nanomaterials for removal of dyes, potentially toxic elements, phenolic compounds and other organic chemicals from aquatic systems. The challenges involved in the development of these novel nanoadsorbents for decontamination of wastewaters have also been examined to help identify future directions for this emerging field to continue to grow. 相似文献