377 research outputs found
Derivation of Inter-Atomic Force Constants of Cu2O from Diffuse Neutron Scattering Measurement
Neutron scattering intensity from Cu2O compound has been measured at 10 K and 295 K with High Resolution Powder Diffractometer at JRR-3 JAEA. The oscillatory diffuse scattering related to correlations among thermal displacements of atoms was observed at 295 K. The correlation parameters were determined from the observed diffuse scattering intensity at 10 and 295 K. The force constants between the neighboring atoms in Cu2O were estimated from the correlation parameters and compared to those of Ag2O.Received: 16 January 2013; Revised: 10 April 2013; Accepted: 15 April 201
Force Constants of Cu Crystals from Diffuse Neutron Scattering Measurement
Diffuse neutron scattering measurement on Cu crystals was performed at 10 K and 300 K. Oscillatory forms were observed in the diffuse scattering intensities. The observed diffuse scattering intensities are analyzed by including the correlation effects among thermal displacements of atoms in the theory. Using the values of correlation effects among neighboring atoms and the values of Debye-Waller temperature parameter, force constants among first, second and third nearest neighboring atoms have been evaluated. The result of correlation effects in Cu crystals are compared to that of ionic crystal and semiconductor. The relation between correlation effects and the inter-atomic distance is not depending much on the crystal binding types. Received: 12 October 2010; Revised: 22 October 2010; Accepted: 16 December 201
Derivation of Inter-Atomic Force Constants of Cu2O From Diffuse Neutron Scattering Measurement
Neutron scattering intensity from Cu2O compound has been measured at 10 K and 295 K with High Resolution Powder Diffractometer at JRR-3 JAEA. The oscillatory diffuse scattering related to correlations among thermal displacements of atoms was observed at 295 K. The correlation parameters were determined from the observed diffuse scattering intensity at 10 and 295 K. The force constants between the neighboring atoms in Cu2O were estimated from the correlation parameters and compared to those of Ag2O.Received: 16 January 2013; Revised: 10 April 2013; Accepted: 15 April 201
Force Constants of Cu Crystals From Diffuse Neutron Scattering Measurement
Diffuse neutron scattering measurement on Cu crystals was performed at 10 K and 300 K. Oscillatory forms were observed in the diffuse scattering intensities. The observed diffuse scattering intensities are analyzed by including the correlation effects among thermal displacements of atoms in the theory. Using the values of correlation effects among neighboring atoms and the values of Debye-Waller temperature parameter, force constants among first, second and third nearest neighboring atoms have been evaluated. The result of correlation effects in Cu crystals are compared to that of ionic crystal and semiconductor. The relation between correlation effects and the inter-atomic distance is not depending much on the crystal binding types. Received: 12 October 2010; Revised: 22 October 2010; Accepted: 16 December 201
Intrinsic Properties of AFe2As2 (A = Ba, Sr) Single Crystal under Highly Hydrostatic Pressure Conditions
We measured the electrical resistivity and ac magnetic susceptibility of
BaFe2As2 and SrFe2As2 single crystals under pressure using a cubic anvil
apparatus. For BaFe2As2, the antiferromagnetic (AF) and structural transitions
are suppressed with increasing pressure. Unexpectedly, these transitions
persist up to 8 GPa, and no signature of a superconducting transition was
observed in the pressure range investigated here. On the other hand, the AF and
structural transitions of SrFe2As2 collapse at around the critical pressure Pc
~ 5 GPa, resulting in the appearance of bulk superconductivity. The
superconducting volume fraction abruptly increases above Pc, and shows a dome
centered at approximately 6 GPa. Our results suggest that the bulk
superconducting phase competes with the AF/orthorhombic phase and only appears
in the narrow pressure region of the tetragonal phase.Comment: 4 pages, 4 figures; accepted for publication in J. Phys. Soc. Jp
Divergence, demography and gene loss along the human lineage
Genomic DNA sequences are an irreplaceable source for reconstructing the vanished past of living organisms. Based on updated sequence data, this paper summarizes our studies on species divergence time, ancient population size and functional loss of genes in the primate lineage leading to modern humans (Homo sapiens sapiens). The inter- and intraspecific comparisons of DNA sequences suggest that the human lineage experienced a rather severe bottleneck in the Middle Pleistocene, throughout which period the subdivided African population played a predominant role in shaping the genetic architecture of modern humans. Also, published and newly identified human-specific pseudogenes (HSPs) are enumerated in order to infer their significance for human evolution. Of the 121 candidate genes obtained, authentic HSPs turn out to comprise only 25 olfactory receptor genes, four T cell receptor genes and nine other genes. The fixation of HSPs has been too rare over the past 6–7 Myr to account for species differences between humans and chimpanzees
Study of quantum effects on atomic displacements in quartz
金沢大学理工研究域数物科学系The crystal structure of quartz (SiO2) was analyzed by neutron powder diffraction at several temperatures in the range of 10–250 K. The temperature dependence of the structure parameters was consistent with our previous results obtained using single-crystal X-ray diffraction above room temperature. Atomic displacements are order parameters for displacive structural phase transitions. The temperature evolution of Si atomic displacement in quartz was analyzed by studying the quantum expansion of the Landau potential. The expansion was found to accurately describe the evolution of the atomic displacement over the entire temperature interval. To the best of our knowledge, such a verification of atomic displacement is the first of its kind. A proportional relationship between spontaneous strain and the square of the atomic displacement was observed over the entire temperature interval. The validity of the obtained characteristic temperature for the quantum effect is discussed and compared with the results of previous Raman-scattering studies
Toll-like receptor 7 is overexpressed in the bladder of Hunner type interstitial cystitis and its activation in the mouse bladder can induce cystitis and bladder pain
自然免疫応答に関する受容体TLR7はHICの膀胱粘膜組織で過剰発現し,マウス膀胱でのTLR7活性化は膀胱痛をともなう炎症を惹起した。よってTLR7を介した反応はHICの病態生理に関与している可能性が示唆された
Contrasting Pressure Effects in Sr2VFeAsO3 and Sr2ScFePO3
We report the resistivity measurements under pressure of two Fe-based
superconductors with a thick perovskite oxide layer, Sr2VFeAsO3 and Sr2ScFePO3.
The superconducting transition temperature Tc of Sr2VFeAsO3 markedly increases
with increasing pressure. Its onset value, which was Tc{onset}=36.4 K at
ambient pressure, increases to Tc{onset}=46.0 K at ~4 GPa, ensuring the
potential of the "21113" system as a high-Tc material. However, the
superconductivity of Sr2ScFePO3 is strongly suppressed under pressure. The
Tc{onset} of ~16 K decreases to ~5 K at ~4 GPa, and the zero-resistance state
is almost lost. We discuss the factor that induces this contrasting pressure
effect.Comment: 5 pages, 4 figures, to be published in J. Phys. Soc. Jpn. No.12
(2009
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