Thorough analysis of the Us vs. Up principal Hugoniot data for liquid CCl4 shows that our values along with all the data reported by other groups except the low pressure results of Dick can be described by the single ...
Thorough analysis of the Us vs. Up principal Hugoniot data for liquid CCl4 shows that our values along with all the data reported by other groups except the low pressure results of Dick can be described by the single smooth function proposed by Woolfolk et al. with the following coefficients: Us/C0=(2.08±0.07)+(1.34±0.04)Up/C0−(1.08±0.07)exp((−1.2±0.2)Up/C0). This satisfies the boundary condition Us=C0=926 m/s at Up=0 and gives the same asymptotic linear relationship as the best-fit expression reported by Dick at shock pressures above ∼16 GPa. On-Hugoniot temperatures calculated using the EOS of Cowperthwaite and Shaw and the revised Us vs. Up are in good agreement with the results of our infrared (IR) measurements and reported optical pyrometry data. The maximum discrepancy does not exceed 5% in the 3.3 to 7 GPa and 10 to 15 GPa shock pressure ranges and is less than 10% for other pressures below 20 GPa. Within the accuracy of our data, the behavior of single-shocked CCl4 does not contradict to the predictions of the constant (∂P/∂T)v model, at least between 3.3 and 7 GPa. All reliable experimental results suggest only two singularities along the principal Hugoniot of CCl4: the threshold of chemical reactions at 7 GPa and complete decomposition at 20 GPa.
Polymerizations of 1-naphthylacetylene (1-NA) and 9-anthrylacetylene (9-AA) by various transition metal catalysts were studied, and properties of the polymers were clarified. 1-NA polymerized with WCl 6 -based catalys...
详细信息
We performed atomic force microscopy measurements on fibroin molecules from the domestic silkworm, Bombyx mori . At low concentrations, we could observe single protein molecules. The shape of the observed molecules is...
详细信息
To develop an systematic in vitro approach for the study of genomic imprinting, we generated a new library of human/mouse A9 monochromosomal hybrids. We used whole cell fusion and microcell-mediated chromosome transfe...
详细信息
To develop an systematic in vitro approach for the study of genomic imprinting, we generated a new library of human/mouse A9 monochromosomal hybrids. We used whole cell fusion and microcell-mediated chromosome transfer to generate A9 hybrids containing a single, intact, bsr-tagged human chromosome derived from primary fibroblasts. A9 hybrids were identified that contained either human chromosome 1, 2, 4, 5, 7, 8, 10, 11, 15, 18, 20, or X. The parental origin of these chromosomes was determined by polymorphic analysis using microsatellite markers, and matched hybrids containing maternal and paternal chromosomes were identified for chromosomes 5, 10, 11 and 15. The imprinted gene KVLQT1 on human chromosome 11p15.5 was expressed exclusively from the maternal chromosome in A9 hybrids, and the parental-origin-specific expression patterns of several other imprinted genes were also maintained. This library of human monochromosomal hybrids is a valuable resource for the mapping and cloning of human genes and is a novel in vitro system for the screening of imprinted genes and for their functional analysis.
A study of resonant-x-ray scattering in a charge-ordered perovskite manganese oxide Nd1/2Sr1/2MnO3 was performed. Dipole-resonant superlattice reflections originating from the orderings of the charge and orbital with ...
A study of resonant-x-ray scattering in a charge-ordered perovskite manganese oxide Nd1/2Sr1/2MnO3 was performed. Dipole-resonant superlattice reflections originating from the orderings of the charge and orbital with Qcharge=(0,1,0) and Qorbital=(0,1/2,0) in the Pbnm setting were observed. Sudden change in the intensity of the superlattice scattering at the transition temperature indicated a strong first-order phase transition. Characteristic dependence on the x-ray polarization was observed not only for orbital-order superlattice scattering but also for charge-order scattering. It should be closely related to the orbital-ordering type (d3x2−r2/d3y2−r2) or (dx2−z2/dy2−z2).
The infrared absorption spectra of H2O and D2O ices were measured with a diamond-anvil cell up to 141 GPa at 298 K. The high-pressure spectra corrected for diamond absorption provided the substantial absorption profil...
The infrared absorption spectra of H2O and D2O ices were measured with a diamond-anvil cell up to 141 GPa at 298 K. The high-pressure spectra corrected for diamond absorption provided the substantial absorption profile of ices over the whole pressure range measured. A sequence of pressure-induced Fermi resonance was observed between the softening stretch mode and the combinations of rotational and bending modes below 55 GPa as reported previously. One rotational mode showed an abrupt increase in the peak frequency at 58±3GPa in H2O ice and 68±3GPa in D2O ice. This can be attributed to a transition from ice VII to proton-tunneling-disordered ice VII. A further transition into proton-disordered ice X was inferred from the spectral change to occur roughly at 65–75 GPa for H2O and 80–90 GPa for D2O.
Phase transition in solid HBr has been investigated by Raman and infrared spectroscopy up to 50 GPa at 298 K. The liquid transforms to a cubic structure (Fm3m) with a bromine fcc lattice at 0.5 GPa and further to an o...
Phase transition in solid HBr has been investigated by Raman and infrared spectroscopy up to 50 GPa at 298 K. The liquid transforms to a cubic structure (Fm3m) with a bromine fcc lattice at 0.5 GPa and further to an orthorhombic structure (Cmc21) consisting of zigzag chains of hydrogen-bonded molecules at 13±0.5GPa. At about 39±2GPa, Raman peaks related to the molecular stretch and rotation disappear and two lattice peaks remain. The Cmc21 orthorhombic structure transforms into a Cmcm orthorhombic structure with symmetrized hydrogen bonds. The symmetrized phase is instable; HBr molecules begin to dissociate after the bond symmetrization and Br2 molecules are formed.
We have investigated depairing effects in Sr2RuO4, the unconventional superconductor in the layered perovskite structure. We prepared crystals of Sr2RuO4 with very low levels of impurity elements, and systematically c...
We have investigated depairing effects in Sr2RuO4, the unconventional superconductor in the layered perovskite structure. We prepared crystals of Sr2RuO4 with very low levels of impurity elements, and systematically controled their superconducting transition temperature Tc ranging from 1.5 to 0.6 K by adjustments of crystal growth conditions. The dependence of Tc on the residual resistivity ρ0 in these crystals suggests that the defects are strong pair breakers, in addition to impurities. We further characterized the effects of pair breaking in this unconventional superconductor. We found that the in-plane coherence length ξab(0) evaluated from Hc2(T) is inversely proportional to Tc, and decreases with increasing mean free path l; the latter behavior is opposite to that of conventional superconductors. In addition, we examined the temperature dependence of Hc2∥c which substantially deviates from the BCS theory and even from a recent theory of a p-wave superconductor.
By means of Ru NMR, magnetic properties in three-dimensional (3D) perovskites SrRuO3 (ferromagnet) and CaRuO3 (exchange enhanced paramagnet) were investigated and compared with those in the two-dimensional (2D) layere...
By means of Ru NMR, magnetic properties in three-dimensional (3D) perovskites SrRuO3 (ferromagnet) and CaRuO3 (exchange enhanced paramagnet) were investigated and compared with those in the two-dimensional (2D) layered perovskite Sr2RuO4 (superconductor), RuO2, and Ru metal (Pauli paramagnet). We found that 4d-spin contributions in the Knight shift and 101(1/T1) of Ru are predominant in SrRuO3, CaRuO3, and Sr2RuO4, but not in nonmagnetic RuO2 and Ru metal. The experimental results that a Stoner factor for CaRuO3 is close to 1 and that a correlation factor estimated from modified-Korringa behavior of Ru−T1 is much less than 1 indicate that CaRuO3 is a nearly ferromagnetic (FM) metal dominated by low-frequency and long-wavelength components of the spin fluctuations (SF). Even though the Stoner factor for Sr2RuO4 also indicates the closeness to the ferromagnetism, the SF in Sr2RuO4 are different from those in CaRuO3. The results combined with the previous 17O NMR study in Sr2RuO4 indicate that the in-plane low-frequency components of SF are exchange enhanced without any significant q dependence due to 2D electronic character (2D nearly FM), while the out-of-plane low-frequency component of SF shows the existence of antiferromagnetic (AFM) SF between layers at low temperature. We propose that this evolution from 3D to 2D nearly FM SF is relevant to the onset of spin-triplet superconductivity in Sr2RuO4. The 2D nearly FM SF in the in-plane 4dxy−pπ band may play a significant role for the stabilization of parallel spin pairing state within the basal plane among various representations of spin-triplet order parameter in Sr2RuO4.
暂无评论