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61.
The temperature dependence and thermal hysteresis of proton and deuteron spin—lattice relaxation times at high fields and a study of the recovery of the proton and deuteron magnetizations in ammonium halides are reported. The anomalies occurring near the order—disorder phase transition are related to structural, dielectric and Raman data. The hysteresis effect and the establishment of long range order are shown to be related. 相似文献
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63.
A solid-state perchlorate sensitive electrode, based upon a radical-ion salt derived from N-ethylbenzothiazole-2,2'-azine. has been prepared. Its response characteristics and high apparent selectivity for perchlorate over many common anions show marked improvements with respect to similar systems which were studied earlier. The general electrode properties observed suggest that it may be considered an acceptable practical alternative to existing liquid-membrane sensors for perchlorate. 相似文献
64.
An analysis is given of the statistics of photon-counting as a means of making measurements in atomic-absorption spectrometry. It is concluded that the simple application of Poisson counting statistics may give an over-optimistic estimate of the error, since other sources of error, such as flame flicker and variable nebulization rate, may be more significant. 相似文献
65.
Carl M Bender Fred Cooper G.S Guralnik Eric Mjolsness Harvey A Rose David H Sharp 《Advances in Applied Mathematics》1980,1(1):22-36
By replacing a differential equation boundary-layer problem by its discrete lattice equivalent we are able to treat the resulting equation as a regular perturbation problem. We obtain the solution on the lattice as a regular perturbation series in inverse powers of the lattice spacing. To obtain the answer to the continuum problem we extrapolate the solution to the lattice problem to zero lattice spacing. This extrapolation, which is a Padé-like procedure, yields good numerical results for a wide range of problems. 相似文献
66.
67.
A rocket borne scanning -m spectrometer was used to observe the night airglow between 1900 and 2300 Å at a resolution of 15 Å. An attitude control system oriented the payload horizontally near apogee (150 km) and pointed the field of view to the north and parallel with the terminator. Progressions from the δ(0, v″) and γ(0, 0) band system of nitric oxide were observed. The observations of the δ-bands and γ-bands are consistent with the relative intensities produced in the preassociation of ground state atomic oxygen and nitrogen. An observation of the v′ = 0, ε-band progression is suggested and is consistent with the presence of a resonance fluorescence contribution near apogee. The A2Σ+ (upper level of the γ-bands) can only be populated by cascade from the C2π state (upper level of the γ-bands) in the preassociation reaction. In the absence of quenching of the A2Σ+ state, the emission rate of the γ-bands can be used as a measure of the C?A transition and thus to deduce the branching ratio to the A2Σ+ state. This branching ratio is estimated to be 0.21±0.04. 相似文献
68.
In this article we address an interesting problem in hyperbolic geometry. This is the problem of comparing different quantities associated to the fundamental group of a hyperbolic manifold (e.g. word length, displacement in the universal cover, etc.) asymptotically. Our method involves a mixture of ideas from both ``thermodynamic' ergodic theory and the automaton associated to strongly Markov groups.
69.
70.
John P. Sutter Thomas Connolley Tim P. Hill Houcheng Huang Doug W. Sharp Michael Drakopoulos 《Journal of synchrotron radiation》2008,15(6):584-592
Finite‐element analysis is frequently used by engineers at synchrotron beamlines to calculate the elastic deformation of a single crystal undergoing mechanical bending or thermal load. ANSYS® Workbench? software is widely used for such simulations. However, although ANSYS® Workbench? software provides useful information on the displacements, strains and stresses within the crystal, it does not yield the local reciprocal lattice vectors that would be required for X‐ray diffraction calculations. To bridge this gap, a method based on the shape functions and interpolation procedures of the software itself has been developed. An application to the double‐crystal bent Laue monochromator being designed for the I12 (JEEP) wiggler beamline at the Diamond Light Source is presented. 相似文献