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41.
Wang ZK Lim HS Liu HY Ng SC Kuok MH Tay LL Lockwood DJ Cottam MG Hobbs KL Larson PR Keay JC Lian GD Johnson MB 《Physical review letters》2005,94(13):137208
The spin dynamics of high-aspect-ratio nickel nanorings in a longitudinal magnetic field have been investigated by Brillouin spectroscopy and the results are compared with a macroscopic theory and three-dimensional micromagnetic simulations. Good agreement is found between the measured and calculated magnetic field dependence of the spin wave frequency. Simulations show that as the field decreases from saturation, the rings switch from a "bamboo" to a novel "twisted bamboo" state at a certain critical field, and predict a corresponding dip in the dependence of the spin wave frequency on the magnetic field. 相似文献
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43.
B.R. Lewis J.H. Carver T.I. Hobbs D.G. McCoy H.P.F. Gies 《Journal of Quantitative Spectroscopy & Radiative Transfer》1980,24(5):365-369
Predissociation linewidths are presented as a function of rotation for the (3-0)-(14-0) Schumann- Runge bands of molecular oxygen. While there may be a slight tendency overall for the linewidths to increase with rotation, it is shown that previous assumptions of linewidths constant with rotation are generally valid within the experimental error for the range of rotation studied, Nn ? 21. There is no evidence for the sudden increase in linewidth with rotation reported elsewhere. 相似文献
44.
B.R. Lewis J.H. Carver T.I. Hobbs D.G. McCoy H.P.F. Gies 《Journal of Quantitative Spectroscopy & Radiative Transfer》1978,20(2):191-203
Experimental oscillator strengths and predissociated linewidths have been measured at room temperature for the (6-0)–(14-0) Schumann-Runge bands of molecular oxygen using the Adelaide 6 m vacuum u.v. monochromator operated at a resolution of about 0.06 Å. Photoelectric detectors were used to measure the u.v. absorption at two different gas pressures for 138 groups of rotational lines distributed throughout the (6-0)–(14-0) bands and the resulting data were interpreted using an equivalent width type of analysis. Experimental measurements of the variation with N″ of the oscillator strengths within each band have been obtained for the first time. Measured oscillator strengths are found to be somwhat higher in general than previously reported values with a slightly faster decrease as N″ increases than is predicted theoretically. The mean predissociated linewidths obtained for each band show a smooth variation with v′, agreeing well with other results for v′=12?14 and lying between previously reported experimental and theoretical values for v′=6?9. The present work provides results which can be used to construct highly accurate synthetic absorption profiles for studies of the atmospheric absorption of u.v. radiation by the Schumann-Runge bands. 相似文献
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47.
Chongbin Zhao B. E. Hobbs A. Ord P. Hornby Shenglin Peng 《Transport in Porous Media》2008,73(1):75-94
In this article, the effect of reactive surface areas associated with different particle shapes on the reactive infiltration
instability in a fluid-saturated porous medium is investigated through analytically deriving the dimensionless pore-fluid
pressure-gradient of a coupled system between porosity, pore-fluid flow and reactive chemical-species transport within two
idealized porous media consisting of spherical and cubic grains respectively. Compared with the critical dimensionless pore-fluid
pressure-gradient of the coupled system, the derived dimensionless pore-fluid pressure-gradient can be used to assess the
instability of a chemical dissolution front within the fluid-saturated porous medium. The related theoretical analysis has
demonstrated that (1) since the shape coefficient of spherical grains is greater than that of cubic grains, the chemical system
consisting of spherical grains is more unstable than that consisting of cubic grains, and (2) the instability likelihood of
a natural porous medium, which is comprised of irregular grains, is smaller than that of an idealized porous medium, which
is comprised of regular spherical grains. To simulate the complicated morphological evolution of a chemical dissolution front
in the case of the chemical dissolution system becoming supercritical, a numerical procedure is proposed for solving this
kind of problem. The related numerical results have demonstrated that the reactive surface area associated with different
particle shapes can have a significant influence on the morphological evolution of an unstable chemical-dissolution front
within fluid-saturated porous rocks. 相似文献
48.
The earliest Australian use of a synchrotron can be dated to 1976 using the accelerator at Daresbury to perform energy dispersive diffraction crystallography of complex mineral structures. This was while it was operating in a parasitic mode in the days before it became a synchrotron storage ring. During the 1970s and 1980s, Australian researchers undertook experiments to study gas-phase atomic structures using Auger spectroscopy at the LURE facility in Paris; protein crystallography at Daresbury, DESY, Photon Factory, and SPEAR; NEXAFS experiments on thin polymer films at SSRL; development of a novel toroidal analyzer for angle-resolved photoelectron spectroscopy at BESSY 1 and later on BESSY 2; and carry out X-ray diffraction and XAFS at the Photon Factory. 相似文献
49.
Jakkrit Suriboot Christopher E. Hobbs Yun‐Chin Yang David E. Bergbreiter 《Journal of polymer science. Part A, Polymer chemistry》2012,50(23):4840-4846
The stability of polyethylene oligomer (PEOlig)‐entrapped salen‐metal complexes toward acidolysis is described. These complexes dissolve in hot toluene and precipitate as hydrophobic powders. The salen species in these precipitates or in precipitates of admixtures of oligomeric complexes and unfunctionalized polyethylene are stable to acid when suspended in acidic methanol for 24 h at 25°C. The lack of metal leaching due to acid‐promoted demetalation was determined using both colorimetric and ICP‐MS analyses. The ICP‐MS results showed the amount of metal loss for PEOlig‐salen‐metal complexes was 0.27%, 0.45%, and 0.79% for half‐salen Cr(III), salen Cr(III), and salen Mn(III) complexes, respectively. These results were in contrast to the reported behavior of low molecular weight salen metal complexes and to results seen with a salen complex bound to divinylbenzene (DVB) crosslinked polystyrene which demetalates under acidic conditions at room temperature. Salen complexes formed with PEOlig complexes also demetalate when the PEOlig‐bound species are in solution at elevated temperature and exposed to acid. These results show that as solids oligomeric polyethylene ligands even without added PE can serve as a protective encapsulating matrix for the solid forms of polymer‐supported catalysts. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
50.
We describe a novel approach to planning and interpretation of data collection activities in military environments, based on the notions of perceptual positions of self, other and detached observer when viewing the same event. We have reinterpreted the results of previous field experiments involving the introduction of advanced equipment as part of soldier modernisation and believe that we now have a better understanding of why some attempts at data collection were not as successful as others. We propose a protocol based on the Army Practitioner providing first position data (subjective), the Analyst Observer and instrumentation providing third position data (objective) and the Subject Matter Adviser giving second position data (speculative). Although there is often a focus on first and third position data during field trials, second position data enables extrapolation to other contexts. This is especially important for exploratory studies investigating future concepts. Taken together, the combination of the three positions leads to a better strategy to enhance data collection of complex military systems. 相似文献