Brillouin light scattering in niobium doped lead zirconate single crystal.

Brillouin light scattering experiments were performed for lead zirconate single crystals doped with niobium. Special attention was paid to the elastic mode softening near phase transition temperatures. The results are compared with data obtained by Raman light scattering experiments. We observed that the interaction between acoustic and optic modes is responsible for symmetry breaking far above TC, leading to polar regions' appearance. No changes in the acoustic mode frequency and its damping are observed at TC, where ε(T) exhibits a maximum value. The absence of these changes and the central peak observed in Raman experiments suggest that the phase transition at TC is mainly of the order-disorder type. The origin of other phase transitions is discussed as well.

Nondestructive analysis of single crystals of selenide spinels by X-ray spectrometry techniques.

The paper presents possibilities and difficulties in nondestructive analysis of small multielement single crystals performed by means of X-ray spectrometry techniques: micro-X-ray fluorescence spectrometry (µ-XRF), energy-dispersive electron probe microanalysis (ED-EPMA), and X-ray photoelectron spectroscopy (XPS). The capability of the X-ray spectroscopy techniques in elemental analysis is demonstrated with the single crystals of selenide spinels of the general formula M(x)N(y)Cr(z)Se(4) (M(+2) and N(+3) are, for example, Zn(+2), V(+3), Ga(+3), Cd(+2), In(+3), and Sb(+3)). The results of the nondestructive analyses (µ-XRF, ED-EPMA, and XPS) are compared with those obtained by inductively coupled plasma optical emission spectrometry (ICP-OES) and wavelength-dispersive X-ray spectrometry (WDXRF) following sample digestion. The present study shows satisfactory agreement between the results of µ-XRF analysis performed using the standardless fundamental parameter method and the results obtained with the WDXRF and ICP-OES analyses. If the measured single crystal is precisely positioned, the difference between µ-XRF and wet analysis (WDXRF and ICP-OES) does not exceed 5% rel. The reliable results of ED-EPMA can be obtained only if the measured area is sufficiently large, i.e., of 200 × 300 µm. Even if this condition is fulfilled, the relative difference between the ED-EPMA and the wet analysis may reach 10% rel. In case of the XPS analysis, the accuracy of results depends on the proper preparation of the sample surface. It should be free of contamination that can be obtained by scraping in situ in ultrahigh vacuum. The ion etching, commonly used for cleaning the surface, leads to preferential sputtering; therefore, the reliable results cannot be obtained.

[Ultrasonographic examination of the heart as a basis for determining the cause of inflammatory infiltration changes in the lungs]. / Ultrasonograficzne badanie serca jako podstawa rozpoznania przyczyny zmian naciekowych w plucach.

Diagnostic difficulties found in a 41 year old female presenting with fever, chills, fainting spells, tachycardia, hypotension, interstitial consolidation in both lungs and enlargement of the cardiac silhouette on a chest radiogram are discussed. Unsuccessful antibacterial and antituberculous therapy led to a supposition of a collagen disease. The diagnosis of a bacterial endocarditis with bacterial pulmonary emboli was made basing on determination of bacterial vegetation on cusps of the tricuspid valve.