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101.
Zhao T Shinde SR Ogale SB Zheng H Venkatesan T Ramesh R Das Sarma S 《Physical review letters》2005,94(12):126601
An external electric field induced reversible modulation of a room temperature magnetic moment and coercive field is achieved in an epitaxial and insulating thin film of dilutely cobalt-doped anatase TiO2. This first demonstration of an electric field effect in any oxide-based diluted ferromagnet is realized in a high quality epitaxial heterostructure of PbZr(0.2)Ti(0.8)O(3)/Co: TiO(2)/SrRuO(3) grown on (001) LaAlO3. The observed effect, which is about 15% in strength in a given heterostructure, can be modulated over several cycles. Possible mechanisms for electric field induced modulation of insulating ferromagnetism are discussed. 相似文献
102.
Coherent backscattering (CBS) of light in random media has been previously investigated by use of coherent light sources. Here we report a novel method of CBS measurement that combines low spatial coherence, broadband illumination, and spectrally resolved detection. We show that low spatial coherence illumination leads to an anomalously broad CBS peak and a dramatic speckle reduction; the latter is further facilitated by low temporal coherence detection. Thus CBS can be observed in biological tissue and other media that previously were beyond the reach of conventional CBS measurements. We also demonstrate, for the first time to our knowledge, spectroscopic analysis of CBS. CBS spectroscopy may find important applications in probing random media such as biological tissue in which depth-selective measurements are crucial. 相似文献
103.
A simple and efficient method has been developed for chemoselective deprotection of phenolic methoxymethyl (MOM) ethers using silica-supported sodium hydrogen sulfate as a heterogeneous catalyst. The conversions occur at room temperature, and the yields of the deprotected phenols are excellent. The method is suitable for deprotection of phenolic MOM ethers of multifunctional bioactive natural products. 相似文献
104.
Roytburd AL Alpay SP Nagarajan V Ganpule CS Aggarwal S Williams ED Ramesh R 《Physical review letters》2000,85(1):190-193
The relations between electrical and mechanical properties of constrained ferroelectric films are analyzed. It is shown that the internal stresses and the elastic constants can be determined through the measurement of the electrical response. The change in the polarization is proportional to internal stresses due to film-substrate misfit, whereas the linear electrical and electromechanical responses to external field do not depend on the misfit and are determined by the film constraint. The theoretical results are successfully applied to PbZr 0.2Ti 0.8O (3) films on (001) LaAlO (3) substrate which exhibit a considerable increase in the saturation polarization due to epitaxial stresses. Significant recovery in the piezoelectric constant and susceptibility is theoretically predicted and experimentally verified for specific film configurations which reduce the degree of constraint. The concept presented in this Letter can be expanded to constrained ferromagnetic and superconductor films. 相似文献
105.
Bosco Christin Maria Arputham Ashwin Ramesh Kumar Chitumalla Arulanandu Herculin Arun Baby Joonkyung Jang Paulpandian Muthu Mareeswaran 《Journal of inclusion phenomena and macrocyclic chemistry》2018,90(1-2):51-60
The supramolecular host–guest investigation of Coumarin 460 (C460), a salient coumarin family dye molecule is studied with a noteworthy host molecule, p-sulfonatocalix[4]arene (p-SC4). The investigation is carried out by both experimental and theoretical approach. The binding affinity of C460 with p-SC4 is experimentally studied using absorption, emission, excited state lifetime and Cyclic Voltammetry methods. The binding constant is around 103 M??1, which shows potent binding. The binding stoichiometry is 1:1. The binding orientations and binding energies are studied using computational simulations. The mode of binding is also established using NMR spectral techniques. 相似文献
106.
Theoretical insight of nitric oxide adsorption on neutral and charged Pdn (n = 1–5) clusters 下载免费PDF全文
Pakiza Begum Pranjal Gogoi Bhupesh Kumar Mishra Ramesh Chandra Deka 《International journal of quantum chemistry》2015,115(13):837-845
Density functional theory (DFT) calculations within the framework of generalized gradient approximation have been used to systematically investigate the adsorption of nitric oxide (NO) molecule on neutral, cationic, and anionic Pdn (n = 1–5) clusters. NO coordinate to one Pd atom of the cluster by the end‐on mode, where the tilted end‐on structure is more favorable due to the additional electron in the π* orbital. On the contrary, in the neutral and cationic Pd2 system, NO coordinates to the bridge site of cluster preferably by the side‐on mode. Charge transfer between Pd clusters and NO molecule and the corresponding weakening of N? O bond is an essential factor for the adsorption. The N? O stretching frequency follow the order of cationic > neutral > anionic. Binding energy of NO on anionic clusters is found to be greater than those of neutral and cationic clusters. © 2015 Wiley Periodicals, Inc. 相似文献
107.
Harry L. Yale James A. Bristol Ramesh B. Petigara 《Journal of heterocyclic chemistry》1975,12(3):489-492
Procedures for the isolation of 1,2-dihydro-4-(trifluoromethyl)-3H,8H-quino[1,8-ab][4,1]-benzoxazepine, 3 , from reaction mixtures containing 3 as the minor component, and the isomer, 1,2-dihydro-11-(trifluoromethyl)-3H,7H-quino[8,1-cd][1,5]benzoxazepin-3-one, 2 , as the major component, are described. The reactivity of 3 toward hydroxylamine and aromatic aldehydes has been investigated and the preparation of derivatives with those reactants is described. 相似文献
108.
Ramesh Ambatwar Sumit Kumar Dhairiya Agarwal Lokesh Chandrakar Gopal L. Khatik 《Journal of heterocyclic chemistry》2024,61(1):163-177
A cobalt(II) perchlorate hexahydrate coordinated synthesis of dihydropyrimidin-ones and -thiones through sonochemistry is developed. Herein, the reaction was demonstrated as a simple, efficient, and one-pot method for synthesizing a series of interesting 3,4-dihydropyrimidin-2(1H)-ones. Further, the reaction mechanism was investigated using mass spectrometry and density functional theory calculations suggesting that a Lewis acid character of cobalt(II) perchlorate hexahydrate plays a crucial role in coordinating carbonyl functionalities and stabilizing the polar intermediates like imine–enamine which further led to cyclized dihydropyrimidin-ones and -thiones. This methodology was further explored to synthesize a gram-scale synthesis of monastrol drug, a kinase inhibitor. 相似文献
109.
Pramesh N. Kapoor Ajay K. Bhagi Ramesh N. Kapoor 《Journal of organometallic chemistry》1991,420(3):321-325
The first organotin(IV), aluminium(III)-μ-oxoisoprovides of the type [R3SnOA](OiPr)2] (R = Me or Ph) have been made by heating of trimethyl- or triphenyl-tin acetate with aluminium isopropoxide. The reactions of these μ-oxoisopropoxides with benzoylacetone in 1:1 and 1:2 molar ratios yielded the compounds of the type [R3SnOAl(OiPr)(bzac)] and [R3SnOAl(bzac)2] (where R = Me or Ph and BZAC = deprotonated benzoylacetone), respectively. 相似文献
110.
An efficient method was developed for the diastereoselective synthesis of novel fused dihydro-1H-furo[2,3-c]pyrazole by a one-pot, four-component reaction of β-keto ester, hydrazine, aromatic aldehyde, and pyridinium ylide in the presence of triethylamine under microwave irradiation in solvent-free conditions in good yields. The merits of this cascade Knoevenagel condensation/Michael addition/cyclization sequence include its high atom economy, good yields, and efficiency of producing three new bonds (two C–C and one C–O) and two stereocenters in a single operation. 相似文献