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101.
An orange/brown ionic and polymeric Mo(V) ion (Mo to Na ratio 2.3:1), soluble in H2O to give stable solutions at pH~6, with UV visible spectrum λmax 318nm, ?(per Mo) 330OM?1 cm?1, has been prepared and partially characterised. Various properties are described, including the conversion to the well established Mo(V) aquo dimer, MO2O42+, on adjustment of [H+] to 0.17–0.50 M, I=0.50 M (H/LiClO4). First-order rate constants, kobs(25°C), determined by conventional spectrophotometry give a good fit to the empirical rate law, 相似文献
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Simon M. Doughty J.Fraser Stoddart Howard M. Colquhoun Alexandra M.Z. Slawin David J. Williams 《Polyhedron》1985,4(4):567-575
The crystal structure of 2Li picrate.dibenzo-36-crown-12.2H2O was determined by X-ray diffraction methods. The 2:1 (metal:ligand) complex crystalli 相似文献
105.
Marin-Montesinos I Brouwer DH Antonioli G Lai WC Brinkmann A Levitt MH 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,177(2):307-317
We examine the influence of continuous-wave heteronuclear decoupling on symmetry-based double-quantum homonuclear dipolar recoupling, using experimental measurements, numerical simulations, and average Hamiltonian theory. There are two distinct regimes in which the heteronuclear interference effects are minimized. The first regime utilizes a moderate homonuclear recoupling field and a strong heteronuclear decoupling field; the second regime utilizes a strong homonuclear recoupling field and a weak or absent heteronuclear decoupling field. The second regime is experimentally accessible at moderate or high magic-angle-spinning frequencies and is particularly relevant for many realistic applications of solid-state NMR recoupling experiments to organic or biological materials. 相似文献
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We grew SrTiO(3) on SrTiO(3)(001) by pulsed laser deposition, while observing x-ray diffraction at the (00(1/2)) position. The drop DeltaI in the x-ray intensity following a laser pulse contains information about plume-surface interactions. Kinematic theory predicts DeltaI/I = -4sigma(1 - sigma), so that DeltaI /I depends only on the amount of deposited material sigma. In contrast, we observed experimentally that |DeltaI /I| < 4sigma(1 - sigma) and that DeltaI /I depends on the phase of x-ray growth oscillations. The combined results suggest a fast smoothing mechanism that depends on surface step-edge density. 相似文献
108.
We demonstrate a mode-locked, erbium-doped fiber laser with its repetition frequency synchronized to a second fiber laser via an intracavity electro-optic modulator (EOM). With servo control from the EOM (bandwidth approximately 230 kHz) and a slower speed intracavity piezoelectric transducer (resonance at approximately 20 kHz), we demonstrate stabilization of the repetition frequency with an in-loop rms timing jitter of 10 fs, integrated over a bandwidth from 1 Hz to 100 kHz. This represents what is to our knowledge the first time an EOM has been introduced inside a mode-locked laser cavity for fast servo action and the lowest timing jitter reported for a mode-locked fiber laser. 相似文献
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Translational isomerization can be induced by changing the anions associated with a bistable rotaxane in which the tetracationic cyclophane (blue box), cyclobis(paraquat-p-phenylene), encircles a dumbbell component containing bispyrrolotetrathiafulvalene (green) and a dioxynaphthalene (red) recognition sites. The rotaxane was isolated as both its hexafluorophosphate and tris(tetrachlorobenzenediolato)phosphate(v) (TRISPHAT(-)) salts. Photophysical measurements and NMR spectroscopy carried out in acetone (CD(3)COCD(3)) and acetonitrile (CD(3)CN) solutions reveal that the much larger TRISPHAT(-) anion favors predominantly the encirclement of the green site by the blue box. 相似文献