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121.
122.
The x-ray anomalous dispersion and optical rotation in the crystalline solid solution NaClO3: NaBrO3
Sodium chlorate and sodium bromate crystals of thes ame structural configuration have opposite senses of optical rotation.
It is also known that these halates exhibit continuous miscibility in solid solution. In the present work, the conjecture
of Bijvoet that in the solid solution of these halates, the crystalline configuration would continue itself, has been directly
verified by two approaches: (i) by optical rotation measurements on single crystals which show an annulling trend in proportion
with composition and (ii) by measuremerts of Bijvoet inequality for several reflections from a single crystal (rich in chlorate)
which shows an agreeable trend with the calculated values for chlorate.
This paper forms a part of Mohanlal’s thesis accepted by the Madurai University for the Ph.D. degree.
We emphasize optical rotation is dextro, if the plane of polarisation is rotated clockwise, for an observer looking towards
the source of light. 相似文献
123.
S N Antani 《Pramana》1975,4(4):184-191
In this work, we present numerical computation of anomalous absorption of a powerful electromagnetic wave incident normally,
on an isothermal plasma with a linear density gradient. We consider first, the “intensity” dependence of anomalous absorption
treating two important cases: one that of a typical high temperature, high density fusion plasma occurring in a laser-pellet
application and the other that of an ionospheric (F-layer) plasma. It is found that for low incident powers, reflection is
almost constant, corresponding essentially, to classical electronion collisions. As we increase the incident power, however,
we find that the reflection starts dropping and the absorption takes over. This result is interpreted in terms of the instability
generated anomalous absorption of the incident wave. Next, we consider the “wavelength” dependence of anomalous absorption,
wherein we observe that the effect of anomalous absorption is increasing for longer wavelengths of the incident laser radiation. 相似文献
124.
The M emission spectra of the elements 55 Cs, 56 Ba, 57 La, and 58 Ce were measured using wavelength dispersive X-ray spectrometry with a TAP crystal as the dispersing element. In total, 34M lines were observed, of which only 13 are contained in the compilation of Bearden. M and M of 56 Ba are among the new lines. They have their origin in a similar process to one that is known for 57 La. The interpretation of these spectra is complicated by the strong overlap of some emission lines with the MIV,V absorption structures, which may lead to anomalous self-absorption effects. Therefore, we have concentrated on spectra taken at a low energy of the exciting electrons, E0=2.5keV. However, in order to illustrate the anomalous self-absorption effects parts of the 2.5keV spectra, of Ba and La, are shown in comparison with the 10keV spectra. 相似文献
125.
Based on the scaling idea of local slopes by López et al. [Phys. Rev. Lett. 94 (2005) 166103], we investigate anomalous dynamic scaling of (d+1)-dimensional surface growth equations with spatially and temporally correlated noise. The growth equations studied include the Kardar-Parisi-Zhang (KPZ), Sun-Guo-Grant (SGG), and
Lai-Das Sarma-Villain (LDV) equations. The anomalous scaling exponents
in both the weak- and strong-coupling regions are obtained, respectively. 相似文献
126.
Tatsuro Otaki 《Optical Review》2001,8(4):284-286
A new phase contrast microscopy technique has been developed which achieves halo reduction by applying an apodization to the Zernike phase contrast method. In this technique, a new apodized phase plate is placed at the back focal plane of the objective. This plate consists of a quarter wave phase shift ring conjugated of the illuminating aperture, which has a 25#x0025; transmittance, and a pair of adjacent rings having 50#x0025; transmittance. The developed technique yields the highest resolution images without a bluish hue effect ever achieved in phase contrast microscopy.This paper was originally presented at the 2nd International Conference on Optical Design and Fabrication, ODF2000 which was held on November 15-17, 2000 at the International Conference Center, Tokyo, Waseda University, Japan. 相似文献
127.
Trichromatic phase manipulation of the response of a two-level medium to an arbitrarily intense probe field 下载免费PDF全文
The phase dependence and independence of the response of a trichromatically
driven two-level medium to an arbitrarily intense probe field have been
studied.
The sum of the relative phases of the sideband components of the
trichromatic field compared to the central component plays a crucial role in
the response of the medium. For a weak probe field, as the sum of the
relative phases changes from The phase dependence and independence of the response of a trichromatieally driven two-level medium to an arbitrarily intense probe field have been studied. The sum of the relative phases of the sideband components of the trichromatic field compared to the central component plays a crucial role in the response of the medium. For a weak probe field, as the sum of the relative phases changes from 0 to π, multiple switching can be achieved, in which switching from normal to anomalous dispersion occurs in multiple separate frequency regimes. The remarkable dependence on the sum phase is also shown for a strong probe field. On the other hand, when the sum of the two relative phases is fixed, the changes in the respective phases have no influence on the response of the medium. 相似文献
128.
Phasing of lysozyme using one-wavelength anomalous scattering of sulphur atoms through the combination of direct methods and density modification 下载免费PDF全文
A new method of combining one-wavelength anomalous scattering (OAS) phasing and density modification has been described, in which the improved phases from density modification axe re-introduced into OAS phasing. In this way, the phases could be improved iteratively until convergence. The OAS phasing method is based on the previously established sign-probability formula, which breaks the phase ambiguity in the OAS phasing. The implementation of this method has been available in CCP4 as OASIS. This method, although based on direct-methods, could also incorporate known phases and figures of merit into its sign-probability formula. In the implementation of OASIS, the known phases axe from the positions of the anomalous scatters. In the current method, the known phases are from the density modification. The current method was tested on phasing a lysozyme crystal using anomalous scattering of sulphur atoms with diffraction data collected on an in-house x-ray source. The resulting map was well connected for the backbone atoms and clearly traceable, with an average map correlation coefficient of 0.6622 for the backbone atoms. 相似文献
129.
Daniele de Sanctis Antonia Beteva Hugo Caserotto Fabien Dobias José Gabadinho Thierry Giraud Alexandre Gobbo Matias Guijarro Mario Lentini Bernard Lavault Trevor Mairs Seán McSweeney Sébastien Petitdemange Vicente Rey‐Bakaikoa John Surr Pascal Theveneau Gordon A. Leonard Christoph Mueller‐Dieckmann 《Journal of synchrotron radiation》2012,19(3):455-461
ID29 is an ESRF undulator beamline with a routinely accessible energy range of between 20.0 keV and 6.0 keV (λ = 0.62 Å to 2.07 Å) dedicated to the use of anomalous dispersion techniques in macromolecular crystallography. Since the beamline was first commissioned in 2001, ID29 has, in order to provide an improved service to both its academic and proprietary users, been the subject of almost continuous upgrade and refurbishment. It is now also the home to the ESRF Cryobench facility, ID29S. Here, the current status of the beamline is described and plans for its future are briefly outlined. 相似文献
130.
The use of constant viscosity, highly elastic polymer solutions, so called Boger fluids, has been remarkably successful in elucidating the behavior of polymeric materials under flowing conditions. However, the behavior of these fluids is still complicated by many different physical processes occurring within a narrow window of observation time and applied shear rate. In this study, we investigate the long-time shear behavior of an ideal Boger fluid: a well characterized, athermal, dilute, binary solution of high molecular weight polystyrene in oligomeric polystyrene. Rheological measurements show that under an applied steady shear flow, this family of polymer solutions undergoes a transient decay of normal stresses on a timescale much longer than the polymer molecule's relaxation time. Rheological and flow visualization results demonstrate that the observed phenomenon is not caused by polymer degradation, phase separation, viscous heating, or secondary flows from elastic instabilities. Although the timescale is much shorter than that associated with polymer migration in the same solutions (MacDonald and Muller, 1996), the appearance of this phenomenon only at the rates where migration has been observed suggests that it may be a prerequisite for observing migration. In addition, we note that through sufficient preshearing of the sample, the normal stress decrease suppresses the elastic instability. These results show that there is considerable uncertainty in choosing the appropriate measure of the fluid relaxation time for consistently modeling the critical condition for the elastic instability, the decay of normal stresses, and the migration of polymer species. 相似文献