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991.
The elastic constants of nine transition metals and four rare-earths and actinides are calculated using the ion-ion interaction
defined by us recently. The volume contribution to elastic moduli is calculated by exploiting the density dependence of the
screening function. The calculated volume contribution to bulk modulus is found to vary between 17.1% and 62.4% for a number
of metals, which is quite significant and play an important role for describing quantitatively the violation of the Cauchy
ratio for these metals. 相似文献
992.
A straightforward synthesis of propargyl alcohols from alkynyl iodides and carbonyl compounds using zinc is described. 相似文献
993.
J.S. Yadav B.V. Subba Reddy Ch. Sreelakshmi G.G.K.S. Narayana Kumar A. Bhaskar Rao 《Tetrahedron letters》2008,49(17):2768-2771
Enzymatic reduction of 2-substituted tetrahydropyran-4-ones with Daucus carota, plant cells as biocatalyst occurred in water under extremely mild and environmentally benign conditions giving a 1:1 mixture of diastereoselectively (2R,4S)- and (2S,4S)-2-aryl- or 2-alkyl-tetrahydropyranols in high yields. 相似文献
994.
Emission spectrum of DyO molecule has been photographed under high resolution in the wavelength region 5000 to 6300 A. The observed bands have been arranged into three different band systems. The rotational structure in the (0, 0) band of system I is partially resolved and analysed. Isotopic shifts have been calculated for various isotopic molecules and compared with observations. Electronic states involved in the transitions have been discussed. 相似文献
995.
The electrochemical synthesis of muscalure, (Z)-9-tricosene( 1 ), has been carried out by coelectrolysis of erucic acid ( 2 ) and propionic acid ( 3 ) in an undivided cell in methanol. To optimize the yield of the cross coupled product 1 , the reaction has been studied in detail by varing different parameters, viz., electrode material, current density, molar ratio of 2 to 3 , degree of partial neutralization and quantity of water in methanol. 相似文献
996.
Satyendra SinghB.C. Yadav Rajiv PrakashBharat Bajaj Jae Rock lee 《Applied Surface Science》2011,257(24):10763-10770
Present paper reports the preparation and characterization of nanorods and mixed shaped (nanospheres/nanocubes) copper ferrite for liquefied petroleum gas (LPG) sensing at room temperature. The structural, surface morphological, optical, electrical as well as LPG sensing properties of the copper ferrite were investigated. Single phase spinel structure of the CuFe2O4 was confirmed by XRD data. The minimum crystallite size of copper ferrite was found 25 nm. The stoichiometry was confirmed by elemental analysis and it revealed the presence of oxygen, iron and copper elements with 21.91, 12.39 and 65.70 atomic weight percentages in copper ferrite nanorods. The band gap of copper ferrite was 3.09 and 2.81 eV, respectively for nanospheres/nanocubes and nanorods. The sensing films were made by using screen printing technology and investigated with the exposure of LPG. Our results show that the mixed shaped CuFe2O4 had an improved sensing performance over that of the CuFe2O4 nanorods, of which a possible sensing mechanism related to a surface reaction process was discussed. Sensor based on mixed shaped copper ferrite is 92% reproducible after one month. The role of PEG in the synthesis for obtaining nanospheres/nanocubes has also been demonstrated. 相似文献
997.
Amit KumarK.L. Yadav 《Physica B: Condensed Matter》2011,406(9):1763-1766
The mixed spinel-perovskite composites of xMnFe2O4-(1-x)BiFeO3 with x=0, 0.1, 0.2, 0.3 and 0.4 were prepared by solid state reaction method. The structure and grain size were examined by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The XRD results showed that the composites consisted of spinel MnFe2O4 and perovskite BiFeO3 phases after being calcined at the temperature 950 °C for 2 h. The grain size ranged from 0.8 to 1 μm. Magnetization was found to increase with increasing concentration of ferrite content. The variation of dielectric constant and dielectric loss with frequency showed dispersion in the low frequency range. Magnetocapacitance was also observed in the prepared composites, which may be the sign of magnetoelectric coupling in the synthesized composites at room temperature. 相似文献
998.
Cadmium sulfide thin films have been deposited on glass substrates by simple and cost effective chemical bath deposition technique. Triethanolamine was used as a complexing agent. The preparative parameters like ion concentration, temperature, pH, speed of substrate rotation and deposition time have been optimized for good quality thin films. The ‘as-grown’ films are characterized for structural, electrical, optical and photoelectrochemical (PEC) properties. The X-ray diffraction (XRD) studies reveal that the films are polycrystalline in nature. Energy-dispersive analysis by X-ray (EDAX) shows that films are cadmium rich. Uniform deposition of CdS thin films on glass substrate is observed from scanning electron microscopy (SEM) and atomic force microscopy (AFM) micrographs. Optical studies reveal a high absorption coefficient (104 cm−1) with a direct type of transition. The band gap is estimated to be 2.47 eV. The film shows n-type conduction mechanism. The photoelectrochemical (PEC) cell with CdS thin film as a photoanode and sulfide/polysulfide (1 M) solution as an electrolyte have been constructed and investigated for various cell parameters. The solar to electrical conversion efficiency (η) and fill factor (ff) are found to be 0.049% and 0.36, respectively. 相似文献
999.
Renu Yadav Nitin Labhsetwar Swati Kotwal Sadhana Rayalu 《Journal of nanoparticle research》2011,13(1):263-271
Nanoparticle technology is being increasingly used in environmental sciences. We prepared single enzyme nanoparticle (SEN)
by modifying the surface of carbonic anhydrase (CA) with a thin layer of organic/inorganic hybrid polymer. SEN-CA appears
to be improving the stability of free enzyme. CA, as ubiquitously found enzyme, is involved in gaseous CO2 sequestration and is being looked as a promising candidate for combating global warming. We report here physical characterization
of SEN-CA using transmission electron microscope (TEM), Fourier-transform infrared analysis (FTIR), X-ray diffraction analysis
(XRD), and energy dispersive X-ray (EDX). Average size of SEN-CA particles appears to be in the range of 70–80 nm. We also
report the effect of SEN formation on the kinetic parameters of free CA such as Michaelis–Menten constant (K
m), maximum reaction velocity (V
max), and storage stability of free CA and SEN-CA. The V
max of SEN-CA (0.02857 mmol/min/mg) and free enzyme (0.02029 mmol/min/mg) is almost similar. K
m has decreased from 6.143 mM for SEN-CA to 1.252 mM for free CA. The stabilization of CA by SEN formation results in improved
the half-life period (up to 100 days). The formation of carbonate was substantiated by using gas chromatography (GC). The
conversion of CO2 to carbonate was 61 mg of CaCO3/mg of CA and 20.8 mg of CaCO3/mg of CA using SEN-CA and free CA, respectively. 相似文献
1000.
Srivastava S Awasthi R Gajbhiye NS Agarwal V Singh A Yadav A Gupta RK 《Journal of colloid and interface science》2011,359(1):104-111
In this study, we describe the development of a facile and effective route for the synthesis of Fe(3)O(4)-based T(1) contrast agent, which can be useful for in vivo magnetic resonance (MR) imaging. Citrate-coated Fe(3)O(4) nanoparticles (6 nm) with a narrow size distribution were synthesized by "one-pot green chemistry route" in diethylene glycol (DEG) solvent. The synthesized nanoparticles were characterized by different analytical techniques including XRD, TEM, HRTEM, and FTIR. At room temperature, nanoparticles exhibited superparamagnetic nature with high saturation magnetization. The longitudinal (r(1)) and transverse (r(2)) relaxivities were found to be 35.45 and 51.81 mM(-1)s(-1), respectively. Contrast agent developed by this method showed a relatively higher longitudinal relaxivity (r(1)) and the lowest relaxivity ratio (r(2)/r(1)=1.46) at 3T MR field. The anionic nature of citric acid facilitated non-specific internalization without impairment of cell viability and functionality. The in vitro studies showed both phagocitic and non-phagocytic uptake of these NPs. In vivo MR imaging of swine showed both T(1) and T(2) contrast effect. 相似文献