253 research outputs found
Field- and pressure-induced phases in SrRuO: A spectroscopic investigation
We have investigated the magnetic-field- and pressure-induced structural and
magnetic phases of the triple-layer ruthenate - SrRuO.
Magnetic-field-induced changes in the phonon spectra reveal dramatic
spin-reorientation transitions and strong magneto-elastic coupling in this
material. Additionally, pressure-dependent Raman measurements at different
temperatures reveal an anomalous negative Gruneisen-parameter associated with
the B mode ( 380 cm) at low temperatures (T 75K), which
can be explained consistently with the field dependent Raman data.Comment: 5 pages, 4 figures final version published in PRL 96, 067004 (2006
Raman scattering studies of temperature- and field-induced melting of charge order in (La,Pr,Ca)MnO
We present Raman scattering studies of the structural and magnetic phases
that accompany temperature- and field-dependent melting of charge- and
orbital-order (COO) in La0.5Ca0.5MnO3 and La0.25Pr0.375Ca0.375MnO3. Our results
show that thermal and field-induced COO melting in La0.5Ca0.5MnO3 exhibits
three stages in a heterogeneous melting process associated with a structural
change: a long-range, strongly JT distorted/COO regime; a coexistence regime;
and weakly JT distorted/PM or FM phase. We provide a complete structural phase
diagram of La0.5Ca0.5MnO3 for the temperature and field ranges 6<=T<=170 K and
0<=H<=9 T. We also investigate thermal and field-induced melting in
La0.25Pr0.375Ca0.375MnO3 to elucidate the role of disorder in melting of COO.
We find that while thermal melting of COO in La0.25Pr0.375Ca0.375MnO3 is quite
similar to that in La0.5Ca0.5MnO3, the field-induced transition from the COO
phase to the weakly JT-distorted/FM phase in La0.25Pr0.375Ca0.375MnO3 is very
abrupt, and occurs at significantly lower fields (H~2 T at T~0 K) than in
La0.5Ca0.5MnO3 (H~30 T at T=0 K). Moreover, the critical field H_c increases
with increasing temperature in La0.25Pr0.375Ca0.375MnO3 in contrast to
La0.5Ca0.5MnO3. To explain these differences, we propose that field-induced
melting of COO in La0.25Pr0.375Ca0.375MnO3 is best described as the
field-induced percolation of FM domains, and we suggest that Griffiths phase
physics may be an appropriate theoretical model for describing the unusual
temperature- and field- dependent transitions observed in
La0.25Pr0.375Ca0.375MnO3.Comment: 14 pages, 8 figures, to be published in PR
Psychosocial Characteristics of Patients with Bronchial Asthma and Coronary Disease: Similarities and Differences
The authors compare two groups of subjects: patients with bronchial asthma and
those with coronary disease, with regard to some social characteristics, abilities and
perception of factors which they conceive are important in the etiology of their disease.
Data were obtained by means of a questionnaire based on a known calibrated scale. A
group of 100 patients with bronchial asthma and a group of 102 patients with coronary
disease were examined. The significance of the difference was tested by c
2, t-test, Wilcoxon’s
test and multivariate discriminative analysis.
The results showed statistically significant differences between the patients with
bronchial asthma and those with coronary disease in some social and psychological
characteristics and also with regard to perception of potential etiological factors of their
disease. However, no difference was found in life style and habits between the coronary
and asthmatic patients
Venus/Mercury swingby with Venus capsule. Preliminary science objectives and experiments for use in advanced mission studies
Venus/Mercury swingby with Venus capsule - preliminary science objectives and experiments for use in advanced mission studie
Gapped Excitations in the High-Pressure Antiferromagnetic Phase of URuSi
We report a neutron scattering study of the magnetic excitation spectrum in
each of the three temperature and pressure driven phases of URuSi. We
find qualitatively similar excitations throughout the (H0L) scattering plane in
the hidden order and large moment phases, with no changes in the
-widths of the excitations at the = (1.407,0,0) and =
(1,0,0) points, within our experimental resolution. There is, however, an
increase in the gap at the point from 4.2(2) meV to 5.5(3) meV,
consistent with other indicators of enhanced antiferromagnetism under pressure.Comment: 5 pages, 3 figures, 1 tabl
Venus - Preliminary science objectives and experiments for use in advanced mission studies
Mission planning and experiment design for future Mariner-type Venus space probe
Water vapor in the tropical lower stratosphere during the driest phase of the atmospheric "tape recorder"
Cirrus and water vapor in the tropical tropopause layer observed by Upper Atmosphere Research Satellite (UARS)
Dizajniranje i vrednovanje okularnih umetaka moksifloksacin hidroklorida
The objective of the present investigation was to prepare and evaluate ocular inserts of moxifloxacin. An ocular insert was made from an aqueous dispersion of moxifloxacin, sodium alginate, polyvinyl alcohol, and dibutyl phthalate by the film casting method. The ocular insert (5.5 mm diameter) was cross-linked by CaCl2 and was coated with Eudragit S-100, RL-100, RS-100, E-100 or Eudragit L-100. The in vitro drug drainage/permeation studies were carried out using an all-glass modified Franz diffusion cell. The drug concentration and mucoadhesion time of the ocular insert were found satisfactory. Cross-linking and coating with polymers extended the drainage from inserts. The cross-linked ocular insert coated with Eudragit RL-100 showed maximum drug permeation compared to other formulations.Cilj rada bio je priprava i evaluacija okularnih umetaka moksifloksacina. Okularni umetak izrađen je od vodene suspenzije moksifloksacina, natrijevog alginata, polivinilnog alkohola i dibutil-ftalata metodom odlijevanja filma. Okularni umetak (promjera 5,5 mm) umrežen je pomoću CaCl2 i obložen Eudragitom S-100, RL-100, RS-100, E-100 ili Eudragit L-100. In vitro drenaža/permeacija lijeka proučavana je koristeći staklenu modificiranu Franzovu difuzijsku ćeliju. Koncentracija lijeka i vrijeme mukoadhezije okularnih umetaka bili su zadovoljavajući. Umrežavanje i oblaganje polimerima produljilo je drenažu iz umetaka. Umreženi okularni umetci obloženi s Eudragit RL-100 pokazali su veću permeaciju lijeka u odnosu na ostale pripravke
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