Pressure-induced phase transition of Bi2Te3 into the bcc structure

The pressure-induced phase transition of bismuth telluride, Bi2Te3, has been studied by synchrotron x-ray diffraction measurements at room temperature using a diamond-anvil cell (DAC) with loading pressures up to 29.8 GPa. We found a high-pressure body-centered cubic (bcc) phase in Bi2Te3 at 25.2 GPa, which is denoted as phase IV, and this phase apperars above 14.5 GPa. Upon releasing the pressure from 29.8 GPa, the diffraction pattern changes with pressure hysteresis. The original rhombohedral phase is recovered at 2.43 GPa. The bcc structure can explain the phase IV peaks. We assumed that the structural model of phase IV is analogous to a substitutional binary alloy; the Bi and Te atoms are distributed in the bcc-lattice sites with space group Im-3m. The results of Rietveld analysis based on this model agree well with both the experimental data and calculated results. Therefore, the structure of phase IV in Bi2Te3 can be explained by a solid solution with a bcc lattice in the Bi-Te (60 atomic% tellurium) binary system.Comment: 12 pages, 5 figure

A Histochemical Study of Cytoplasmic Bodies in the Thymo-lymphatic Tissues of the mouse

At the beginning of the 20th century, the cytoplasmic bodies which appear in the lymphoid tissues of mammals had received much attention of haematologists, in the relation to the origin of the blood platelets. However, since Wright described and figured in 1910 the process of cytoplasmic budding of megakaryocytes by the use of his own technics, the biological significance of the cytoplasmic bodies in the lymphoid tissues has been ignored until now. Recent works on the formation of antibodies in the lymphoid tissue seem to suggest, on the other hand, that these bodies would play an important role in the immune response. Consequently, we attended a renewed study of these bodies. In this paper we described the results of histochemical observations on these bodies in, the mesenteric lymph node and thymus of adult mice. The chief findings are as follows: 1. Cytoplasmic bodies are found in large number in the mesenteric lymph node of adult mice. They also occur in the thymus, though in much smaller numbers. 2. Cytoplasmic bodies in the thymolymphatic tissues vary greatly in size, from the size of blood platelets to that of small lymphocytes, and are commonly round in shape. They often contain pyroninophilic granules. 3. Staining of these bodies with methyl green-pyronin and acridine orange revealed that they contain abundant RNA. However, no evidence was obtained for the presence of DNA in these bodies. 4. After digestion of the samples with RNase, the pyroninophilia of these bodies disappeared completely. This suggests that the pyroninophilic granules of these bodies might be regarded as ribosomes

Do SnI4 molecules deform on heating and pressurization in the low-pressure crystalline phase ?

Extended X-ray absorption fine structure (EXAFS) measurements on the crystalline SnI4 were carried out to investigate the change in the environment around a Sn atom at high pressures and temperatures. We could not find clear evidence on the symmetry change of molecules even close to the melting points, where the melting curve becomes abnormally flat against pressure