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11.
P. J. Skevington M. A. G. Halliwell M. H. Lyons S. J. Amin M. A. Z. Rejman-Greene G. J. Davies 《Journal of Crystal Growth》1992,120(1-4):328-332
InP/InGaAs multiple quantum well structures with up to 200 periods have been grown by CBE. These structures exhibit exceptional lateral uniformity, measured as ±1 Å in period, ±13 ppm in lattice mismatch and ±0.5 nm in wavelength across a 2 inch wafer. Good surface morphology, sharp interfaces and excellent growth control have all been demonstrated. 相似文献
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Olga Ordeig Craig E Banks Trevor J Davies F Javier del Campo Francesc Xavier Mu?oz Richard G Compton 《Analytical sciences》2006,22(5):679-683
Gold ultra-microelectrode arrays are used to explore the electrochemical oxidation of hydroxide ions and are shown to be analytical useful. Two types of ultra-microelectrode arrays are used; the first consist of 256 individual electrodes of 5 microm in radius, 170 of which are electrochemically active in a cubic arrangement which are separated from their nearest neighbour by a distance of 100 microm. The second array compromises 2597 electrodes of 2.5 microm in radius and of which 1550 of which are electrochemically active in a hexagonal arrangement separated by the nearest neighbour by 55 microm. Well defined voltammetric waves are found with peak currents proportional to the concentration of hydroxide ions in the range 50 microM to 1 mM. Detection limits of 20 microM using the 170 ultra-microelectrode and 10 microM with the 1550 ultra-microelectrode array are shown to be possible but with a higher sensitivity of 4 mA M(-1) observed using the 1550 ultra-microelectrode array compared to 1.2 mA M(-1) with the 170 ultra-microelectrode array. 相似文献
15.
Demin D. L. Dzhelepov V. P. Filchenkov V. V. Grafov N. N. Grebinnik V. G. Migachev D. V. Konin A. D. Rudenko A. I. Sidorov V. T. Zhestkov Yu. G. Zinov V. G. Davies J. D. Bom V. R. van Eijk C. W. E. 《Hyperfine Interactions》1996,101(1):13-19
The ddµ molecule formation rate is experimentally measured for the two hyperfine states of the dµ-atom in the temperature range of 5–30 K. Results are consistent with a preliminary measurement by the TRIUMF group and contradict theoretical predictions. The work has been performed on the JINR phasotron (Dubna). 相似文献
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Maria A. Curtin Irwin A. Taub Kenneth Kustin Narith Sao Jeremy R. Duvall Katharine I. Davies Christopher J. Doona Edward W. Ross 《Research on Chemical Intermediates》2004,30(6):647-661
The slow reaction between peroxodisulfate and formate is significantly accelerated by ascorbate at room temperature. The products of this induced oxidation, CO2 and oxalate (C2O2–
4), were analyzed by several methods and the kinetics of this reaction were measured. The overall mechanism involves free radical species. Ascorbate reacts with peroxodisulfate to initiate production of the sulfate radical ion (SO–
4), which reacts with formate to produce carbon dioxide radical ion (CO–
2) and sulfate. The carbon dioxide radical reacts with peroxodisulfate to form CO2 or self-combines to form oxalate. Competition occurring between these two processes determines the overall fate of the carbon dioxide radical species. As pH decreases, protonation of the carbon dioxide radical ion tends to favor production of CO2. 相似文献
20.
B. Malaekeh-Nikouei H. Nassirli N. Davies 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):245-250
Cyclodextrins (CDs) are cyclic oligosaccharides that form inclusion complexes with lipophilic molecules through their hydrophobic
central cavity. In this study, the effect of α-CD, hydroxylpropyl-β-CD (HP-β-CD) and mixtures of these two CDs on the aqueous
solubility of cyclosporine A (CyA) was investigated. Infrared spectroscopy and thermal analysis were used to confirm CyA-CD
complex formation. CyA aqueous solubility was increased by 10 and 80 fold in the presence of α-CD and HP β-CD, respectively.
The phase-solubility profile for HP-β-CD was linear while that for α-CD had positive deviation from linearity. In the presence
of constant concentration of α-CD (15% w/v), aqueous solubility of CyA was further increased upon addition of HP-β-CD up to
a concentration of 20% w/v. At higher HP-β-CD concentrations, aqueous solubility of CyA was observed to decrease. Addition
of sodium acetate (up to 5% w/v) to aqueous solutions containing 20% w/v HP-β-CD and increasing concentrations of α-CD resulted
in a significant reduction in CyA solubility. Complex formation between CyA and both α-CD and HP-β-CD was confirmed by differential
scanning calorimetry (DSC). No significant changes were observed in the IR spectra of either CyA or CD following complex formation
suggesting chemical interaction between CyA and the CD was unlikely. Phase-solubility studies showed that α-CD had a much
greater effect on the solubility of CyA than HP-β-CD. Addition of HP-β-CD to aqueous solutions of α-CD affected the solubility
of CyA in these systems. A mixture of 15% w/v α-CD and 20% w/v HP-β-CD was optimal for increasing aqueous solubility of CyA. 相似文献