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91.
Pulse radiolysis technique has been used to characterise the transients formed by the reaction of sulphacetamide with eaq
- and subsequently study the electron transfer reactions from the transient to various electron acceptors such as thionine,
safranine-T and methyl viologen. The results indicate that the semi-reduced sulphacetamide species are highly reducing in nature as they
transfer electrons to various dyes with near diffusion controlled rates (k > 109dm3mol−1s−1) in alkaline and acidic solutions. The influence of oxygen on the decay behaviour of semi-reduced species has been investigated
and the results show that O2 reaction with SA− is very fast (k = 1.5 × l09dm3mol−1s−1) and leads to the formation of a permanent-coloured product. Reactions of H.atoms resulted in the formation of two transient
species whose spectral, kinetic and acid-base characteristics have also been investigated. 相似文献
92.
93.
This paper studies the effects of a circular magnetic field on the flow of a conducting fluid about a porous rotating disk. Using modern quasi-Newton and globally convergent homotopy methods, numerical solutions are obtained for a wide range of magnetic field strengths, suction and injection velocities and Alfven and disk speeds. Results are presented graphically in terms of three non-dimensional parameters. There is excellent agreement with previous work and asymptotic formulae. 相似文献
94.
95.
The determination of persulphate in a ca. 12.5 N sulphuric acid solution by direct titration with permanganate is described. The results are satisfactory but the conditions are critical. 相似文献
96.
Chen Y Pai A Somiya K Kawamura S Sato S Kokeyama K Ward RL Goda K Mikhailov EE 《Physical review letters》2006,97(15):151103
We propose a class of displacement- and laser-noise-free gravitational-wave-interferometer configurations, which does not sense nongeodesic mirror motion and laser noise, but provides a nonvanishing gravitational-wave signal. Our interferometers consist of four mirrors and two beam splitters, which form four Mach-Zehnder interferometers. By contrast to previous works, no composite mirrors with multiple reflective surfaces are required. Each mirror in our configuration is sensed redundantly, by at least two pairs of incident and reflected beams. Displacement- and laser-noise-free detection is achieved when output signals from these four interferometers are combined appropriately. Our 3-dimensional interferometer configuration has a low-frequency response proportional to f2, which is better than the f3 achievable by previous 2-dimensional configurations. 相似文献
97.
Kampschulte L Lackinger M Maier AK Kishore RS Griessl S Schmittel M Heckl WM 《The journal of physical chemistry. B》2006,110(22):10829-10836
This work presents a scanning tunneling microscopy (STM) based study of benzenetribenzoic acid (BTB) monolayer structures at the liquid-solid interface. On graphite(0001) the tailored molecules self-assemble into 2D supramolecular host systems, suitable for the incorporation of other nanoscopic objects. Two crystallographically different BTB structures were found-both hydrogen bonded networks. A specific structure was deliberately selected by solvent identity. One of the BTB polymorphs is a 6-fold chicken-wire structure with circular, approximately 2.8 nm wide cavities. The other structure exhibits an oblique unit cell and a different hydrogen bonding pattern. The large cavity size of the chicken-wire structure was made possible through comparatively strong 2-fold hydrogen bonds between carboxylic groups. In addition, the low conformational flexibility of BTB was supportive to combat the tendency for dense packing. 相似文献
98.
Shumate WJ Mattern DL Jaiswal A Dixon DA White TR Burgess J Honciuc A Metzger RM 《The journal of physical chemistry. B》2006,110(23):11146-11159
We report spectroscopic characterization and unimolecular rectification (asymmetric electrical conduction) measurements of three donor-sigma-acceptor (D-sigma-A) compounds N-(10-nonadecyl)-N-(1-pyrenylmethyl)perylene-3,4,9,10-bis(dicarboximide) (1), N-(10-nonadecyl)-N-(4-[1-pyrenyl]butyl)perylene-3,4,9,10-bis(dicarboximide) (2), and N-(10-nonadecyl)-N-(2-ferrocenylethyl)perylene-3,4,9,10-bis(dicarboximide) (3). These molecules were arranged as one-molecule thick Langmuir-Blodgett monolayers between Au electrodes. In such an "Au | D-sigma-A | Au" sandwich, molecule 1 is a unimolecular rectifier, with rather small rectification ratios (between 2 and 3 at +/-1 V) that decrease upon cycling. Molecule 2 does not rectify. Molecule 3 rectifies, with a rectification ratio of between 14 and 28 at +/-1 V; the through-film rectification and currents persist, even with scans of +/-2 V, for up to 40 cycles of measurement. Qualitative arguments, based on a two-level rectification mechanism, are consistent with the current asymmetries observed in the monolayers of 1 and 3. 相似文献
99.
Hwang SH Moorefield CN Wang P Jeong KU Cheng SZ Kotta KK Newkome GR 《Chemical communications (Cambridge, England)》2006,(33):3495-3497
Using regioselective dendritic functionalized cellulose, CdS quantum dot nanoparticles were prepared and their photo-optical properties and morphology as well as the preliminary biocompatibility of the hybrid were investigated. 相似文献
100.
Archana Gupta Poonam Tandon V. D. Gupta Shantanu Rastogi G. P. Gupta 《Journal of Macromolecular Science: Physics》2013,52(4):401-426
Poly-N ?(p-bromobenzoyl-l-ornithine) (PBrBO) is one of the few biopolymers existing in the rare ω-helical (fourfold) conformation. It can be obtained from the α form through an irreversible heat treatment. A study of its normal modes and dispersive behavior shows several interesting features such as “crossing over,” “repulsion with character exchange,” and Von Hove type “singularities” which lead to a fuller interpretation of its IR spectra. The existence of alternately different side-chain conformations, which makes the phonon problem too large to solve directly, has been taken into account by considering the vibrations of the PBrBO chains with two independent conformations. Detailed study of skeletal, amide, and side-chain modes is reported, and the results have been used for the calculation of specific heat via density of states. 相似文献