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971.
Rao NM Vijayalakshmi RP Reddy DR Reddy BK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(2):688-691
(ZnS)1-x(MnTe)x luminescent powder samples with x=0.02, 0.05, 0.10, 0.15, 0.20 and 0.25 were prepared by solid-state reaction method. EPR spectra were recorded at room temperature (300K) in the frequency range 8.8-9.6GHz for samples of all compositions. The line width (DeltaH) and the number of spins increased with MnTe concentration. Room temperature dc magnetic susceptibility measurements were carried out using vibrating sample magnetometer. Susceptibility of the samples increased with MnTe content. 相似文献
972.
973.
Isolation and characterisation of compounds, 1-(2′-hydroxy-4′-methoxyphenyl)-3-(4″-methoxyphenyl)-2-hydroxypropane-1,3-dione (1), 5-hydroxyflavone (2), 3,5,7,3′,4′-pentahydroxyflavone (3), 3,5,7,2′,4′-pentahydroxyflavone (4) and 5,7,3′,4′-tetrahydroxyflavone-3-O-rhamnoside (5) are reported from the air dried flowering buds of Bauhinia tomentosa Linn. Their structures are determined on the basis of extensive chemical and spectral evidences. Compound (1) is reported for the first time from the plant source. While compounds (2) and (4) are reported for the first time from this genus, compound (2) is reported for the second time from the natural source. 相似文献
974.
J. Arout Chelvane Mithun Palit S. Pandian M. Manivel Raja V. Chandrasekaran 《Hyperfine Interactions》2008,181(1-3):87-91
35Cl NQR measurements were carried out between 77 and 209 K for 3-chlorothiophene, which has a glass transition in a stable crystalline state. An NQR signal with full widths of about 100 kHz at half maximum was observed in this temperature range. The spin-lattice relaxation time T 1 was measured at the peak frequencies. The activation energy Δε a obtained from the results of the T 1 measurements showed a good agreement with those estimated from calorimetric measurements. 相似文献
975.
Alvarez CS García F Humphrey SM Hopkins AD Kowenicki RA McPartlin M Layfield RA Raja R Rogers MC Woods AD Wright DS 《Chemical communications (Cambridge, England)》2005,(2):198-200
The reactions of [MeAl(2-py)3Li.thf] (1) with FeCl2 or Cp2Mn in toluene-thf give simple access to the Group 13-transition metal heterometallic complexes [{MeAl(2-py)3}2M][M = Fe (2), Mn (3)]; complex has been shown to be a highly selective styrene epoxidation catalyst in air. 相似文献
976.
Mateo Alajarín Carmen López-Leonardo Pilar Llamas-Lorente Rosalía Raja 《Tetrahedron letters》2007,48(39):6987-6991
Nitrogen and sulfur nucleophiles, such as amines, thiophenols, and aminophosphanes, add to the triple bond of P-ethynyl-λ5-phosphazenes to give regio and diastereoselectively P-ethenyl-λ5-phosphazenes. An equally selective substitution reaction, occurring by an addition-elimination pathway, on bis(iminophosphoranyl)ethenes has been also achieved. 相似文献
977.
Various nitrogen-fused tricyclic compounds, having benzoindolizidine and benzopyrrolizidines ring systems were synthesized via ene-ene metathesis using the first and second-generation Grubbs catalyst. The ene-ene metathesis proceeded smoothly in refluxing CH2Cl2 with 3.0 mol % of G1, giving good yields (78-86%) of the benzoindolizidine products 12a,b. The benzopyrrolizidine 6 was prepared after optimization in 64% yield by using 5.0+5.0 mol % of G2. The resulting olefin moiety of the indolizidine framework is a suitable precursor for polyhydroxy structures via the Sharpless process. The structures of the polyhydroxylated adducts were determined by 1H NMR spectra and single-crystal X-ray analysis. 相似文献
978.
Dunuwille M Davidson AJ Chellappa RS Dattelbaum DM Yoo CS 《The journal of physical chemistry. A》2011,115(42):11889-11896
The energetic material ammonium nitrate (AN, NH(4)NO(3)) has been studied under both hydrostatic and nonhydrostatic conditions using diamond anvil cells combined with micro-Raman spectroscopy and synchrotron X-ray powder diffraction. The refined powder X-ray data indicates that under hydrostatic conditions AN-IV (orthorhombic, Pmmn) is stable to above 40 GPa. In one nonhydrostatic compression experiment a volume collapse was observed, suggesting an isostructural phase transition to a "metastable" phase IV' between 17 and 28 GPa. The structures of phase IV and IV' are similar with the subtle difference in the hydrogen-bonding network; that is, a noticeably shorter N1···O1 distance seen in phase IV'. This hydrogen bond has a significant component along the b-axis, which proves to be the most compressible until cell axis over the entire pressure range. It is likely that the shear stress of the nonhydrostatic experiment drives the phase IV-to-IV' transition to occur. We compare the present isotherms of phase IV and IV' in both static and nonhydrostatic conditions with the previously obtained Hugoniot and find that the nonhydrostatic isotherm approximately matches the Hugoniot. On the basis of this comparison, we conjecture that a chemical reaction or phase transition may occur in AN under dynamic pressure conditions at 22 GPa. 相似文献
979.
Kondapalli Venkata Gowri Chandra Sekhar Thripuraribhatla Venkata Naga Varuna Tara Sasank Hunsur Nagendra Nagesh Narva Suresh Kalaga Mahalakshmi Naidu Amaroju Suresh 《中国化学快报》2013,24(12):1045-1048
A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, ^1H NMR, ^13C NMR and HRMS. 相似文献
980.
The difficulty in definitively linking outcomes of managerial action to organizational outcomes has been a festering issue in organizational research. The problem arises because it is not easy to separate the distinctive contributions of managers at intermediate stages, as well as the contribution of external factors beyond the control of managers. Specifically, certain managerial actions focusing on exploratory or exploitative innovation produce an intermediate output, organizational knowledge. From this base of organizational knowledge, further management actions craft the final output that eventually faces the market test. Drawing from complexity concepts, I argue that the probability of correctly fashioning the subset of key elements in the intermediate output may be a good measure of the probability of organizational success. I use March’s iconic computational simulation model to demonstrate the merits of this principle. I model the effect of complexity on managerial intentionality towards exploratory and exploitative innovation. I elicit important insights for research and practice by comparing organizational knowledge outcomes with the outcomes for probability of organizational success, in stable and moderately turbulent environment. 相似文献