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951.
Malvi B Panda C Dhar BB Gupta SS 《Chemical communications (Cambridge, England)》2012,48(43):5289-5291
An [Fe(III)(biuret-amide)] complex has been immobilized onto mesoporous silica nanoparticles via Cu(I) catalyzed azide-alkyne click chemistry. This hybrid material functions as an efficient peroxidase mimic and was successfully used for the quantitative determination of hydrogen peroxide and glucose via a one-pot colorimetric assay. 相似文献
952.
Kumar I Mir NA Gupta VK Rajnikant 《Chemical communications (Cambridge, England)》2012,48(55):6975-6977
A new method for asymmetric synthesis of 2,3-substituted pyrrolidines from N-PMP aldimines and succinaldehyde via formal [3+2] cycloaddition is reported. This reaction involves proline catalyzed direct Mannich reaction and acid catalyzed reductive cyclization with high yields (up to 78%) and excellent enantioselectivities (up to >99%). 相似文献
953.
R. K. Kotnala Rekha Gupta Jyoti Shah M. Abdullah Dar 《Journal of Sol-Gel Science and Technology》2012,64(1):149-155
Nano-crystals of Li0.35Zn0.3Fe2.35O4 ferrite have been synthesized using citrate precursor method. The sample synthesized was sintered at different temperatures in order to vary their crystallite size. The average crystallite size was found in the range 24?C57?nm by varying the temperature from 300 to 1,100?°C. X-ray diffraction measurements confirmed the formation of cubic spinel structure at all the sintering temperatures in this work. The high frequency performance of the ferrite samples were estimated by measuring the frequency dispersion of the dielectric constant, dielectric loss and ac electrical conductivity. The dielectric constant has been observed to show normal behavior with frequency and decreases with the decrease in crystallite size. It is also observed that decrease in dielectric constant depends on sintering temperature because of lithium evaporation at higher temperature. A low value of dielectric constant and dielectric loss has been found, which makes them applicable for high frequency applications by decreasing the skin effect. The impedance spectroscopy technique has been used to study the effect of grain and grain boundary on the electrical properties of Li0.35Zn0.3Fe2.35O4 ferrite. The analysis of data shows only one semi-circle corresponding to the grain boundary volume suggesting that the conduction mechanism takes place predominantly through grain boundary volume in the prepared samples. 相似文献
954.
Mahadik Satish A. Mahadik D. B. Parale V. G. Wagh P. B. Gupta Satish Venkateswara Rao A. 《Journal of Sol-Gel Science and Technology》2012,62(3):490-494
A facile route to methyltrimethoxysilane (MTMS) based recoverable superhydrophobic silica coatings with dual-scale roughness
obtained through the single step base catalyst sol–gel process. Superhydrophobic silica coatings have shown static water contact
angle near about 170 ± 1° and dynamic water contact angle up to 2 ± 1°. Superhydrophobic-superhydrophilic switching feature
also achieved by alternating heat treatment and bath surface modification with Trimethylchlorosilane (TMCS) at room temperature
(26 °C). Furthermore, the superhydrophobic state could be transformed into superhydrophilic state by slow rate heat treatment.
These studies present a very simple strategy for the fabrication of recoverable superhydrophobic surfaces. 相似文献
955.
Chetan K. Modi Parthiv M. Trivedi Sanjeev K. Gupta Prafulla K. Jha 《Journal of inclusion phenomena and macrocyclic chemistry》2012,74(1-4):117-127
A series of zeolite-Y encapsulated hybrid catalysts, [M(STCH)·xH2O]-Y have been prepared by encapsulating Schiff base complexes [where M?=?Mn(II), Fe(II), Co(II), Ni(II); (x?=?3) and Cu(II); (x?=?1); H2STCH?=?salicylaldehyde thiophene-2-carboxylic hydrazone] in zeolite-Y matrix by flexible ligand method. These hybrid materials have been characterized by various physico-chemical techniques such as ICP-OES, elemental analyses, (FT-IR and electronic) spectral studies, BET, scanning electron micrographs, thermal analysis and X-ray powder diffraction patterns. X-ray powder diffraction analysis reveals that the structural integrity of the mother zeolite in the hybrid material remained intact upon immobilization of the complex. Density functional theory is employed to calculate the relaxed structure, bond angle, bond distance, dihedral angle, difference of highest occupied molecular orbital and lowest unoccupied molecular orbital energies gap and electronic density of states of ligand and their neat transition metal complexes. The hybrid materials are active catalysts for the hydroxylation of phenol using hydrogen peroxide (30% H2O2) as an oxidant in order to selectively synthesize catechol or hydroquinone, amongst them [Cu(STCH)·H2O]-Y shown the highest % of selectivity towards catechol (81.3%). 相似文献
956.
Sunil K. Arya Shibu Saha Jaime E. Ramirez-Vick Vinay Gupta Shekhar Bhansali Surinder P. Singh 《Analytica chimica acta》2012
Biosensors have shown great potential for health care and environmental monitoring. The performance of biosensors depends on their components, among which the matrix material, i.e., the layer between the recognition layer of biomolecule and transducer, plays a crucial role in defining the stability, sensitivity and shelf-life of a biosensor. Recently, zinc oxide (ZnO) nanostructures and thin films have attracted much interest as materials for biosensors due to their biocompatibility, chemical stability, high isoelectric point, electrochemical activity, high electron mobility, ease of synthesis by diverse methods and high surface-to-volume ratio. ZnO nanostructures have shown the binding of biomolecules in desired orientations with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes ZnO nanostructures suitable candidate for future small integrated biosensor devices. This review highlights recent advances in various approaches towards synthesis of ZnO nanostructures and thin films and their applications in biosensor technology. 相似文献
957.
RF sputtered p-type nickel oxide (NiO) thin film exhibiting tunable semiconductor character which in turns enhanced its functional properties. NiO thin film with high hole mobility is developed as a potential matrix for the realization of glucose biosensor. NiO thin film prepared under the optimized deposition conditions offer good electrical conductivity (1.5 × 10−3 Ω−1-cm−1) with high hole mobility (2.8 cm2 V−1 s−1). The bioelectrode (GOx/NiO/ITO/glass) exhibits a low value of Michaelis–Menten constant (Km = 1.05 mM), indicating high affinity of the immobilized GOx toward the analyte (glucose). Due to the high surface coverage (2.32 × 10−7 mol cm−2) of the immobilized enzyme on to the NiO matrix and its high electrocatalytic activity, the prepared biosensor exhibits a high sensitivity of 0.1 mA (mM−1-cm−2) and a good linearity from 25 to 300 mg dL−1 of glucose concentration with fast response time of 5 s. Various functional properties of the material (mobility, crystallinity and stress) are found to influence the charge communication feature of NiO thin film matrix to a great extent, resulting in enhanced sensing response characteristics. 相似文献
958.
Trichloromethyl phenyl ketone benzoylates primary and secondary aliphatic alcoholic groups in compounds also containing a phenolic group in the presence of 2–10 mol % of PMDETA organocatalyst at room temperature in high yields and excellent selectivity. It also shows the potential to selectively benzoylate primary alcoholic groups of aminoarylalkanols and primary-secondary diols as well as primary amino group of alkyl amines in the presence of aryl amines under similar conditions. A rationale for the selectivity and efficiency of the reaction has been provided. 相似文献
959.
In this article we obtain a new class of well behaved charged solutions by using particular forms of the metric potential
g
44 and electric intensity, which involves a parameter K. The metric describing the superdense stars joins smoothly with the Reissner-Nordstrom metric at the pressure free boundary.
This class of solutions describes well behaved charged fluid balls. The class of solutions gives range of parameter K (0.13≤K≤1.9999) for which the solution is well behaved hence, suitable for modeling of super dense star. The interior of the stars
possess there energy density, pressure, pressure-density ratio and velocity of sound to be monotonically decreasing towards
the pressure free interface. In view of the surface density 2×1014 gm/cm3, the maximum mass of the charged fluid balls and corresponding radius are 0.4711M
Θ and 7.0122 km. The red shift at the centre and boundary are found to be 0.1640 and 0.1100 respectively. 相似文献
960.
A set of three static fluid spheres once derived by Matese and Whitman (in Phys. Rev. D 22:1270, 1980) are charged by means of a particular electric intensity to obtain compact objects like white dwarfs, quark stars and neutron
stars etc. The charged objects so obtain and their neutral counterparts are analysed on astrophysical grounds. This revealed
that two of the charged spheres and one of the neutral seed solutions are well behaved. The corresponding red shift and adiabatic
index together with other physical entities like pressure, density and velocity of sound through the star models are studied
systematically. 相似文献