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Ti2O3 exhibits unique metal–insulator transition (MIT) at ~ 450 K over a wide temperature range of ~ 150 K. The close relationship between MIT and crystal deformation has been proposed. However, as physical properties are governed by the thermodynamic equilibrium in bulk systems, conducting experimental studies under different lattice deformations remains challenging. Epitaxial thin films can offer high flexibility to accommodate adaptive crystal lattices and provide efficient platforms for investigating the MIT. In this study, we report the synthesis of corundum-type Ti2O3 films on various growth temperatures. We found that the metallic ground states appeared in the films grown at low temperatures. The electronic ground states were further investigated by the electronic-structure calculations. Results suggest that the electrical properties of Ti2O3 films were governed by the c/a ratio of the crystal structure, and the absence of the MIT was attributed to the lattice deformation characterized by an elongated c lattice constant. [ABSTRACT FROM AUTHOR]

Spatial structures of ablative mass flow produced by femtosecond laser pulses are studied. In experiments with a gold film, the Ti:sapp laser pulse having a focal size of 100 microns on a target was used, while a soft X-ray probe pulse was utilized for diagnostics. The experimental data are compared with simulated mass flows obtained by two-temperature hydrodynamics and molecular dynamics methods. Simulation shows evolution of a thin surface layer pressurized after electron-ion thermalization, which leads to melting, cavitation and formation of spallation liquid layer. The calculated asymptotic surface velocity of this layer as a function of fluence is in reasonably good agreement with experimental data. [ABSTRACT FROM AUTHOR]

Experimental and theoretical investigations of aluminum (Al) and gold (Au) surface modification by soft X-ray laser pulse are presented. Well-polished samples of Al and Au are irradiated by ps-duration pulse with wavelength of 13.9 nm at the energy range of 24-72 nJ. Differences in the melting and the ablation processes for those materials are observed. It is shown that at low laser pulse energy, the nanoscale ripples on the surface may be induced by melting without following ablation. In that case, the nanoscale changes in the surface are caused by splash of molten metal under gradient of fluence. At higher laser pulse energy, the ablation process occurs and craters are formed on the surface. However, the melting determines the size of the modified surface at all ranges of the laser energies. For interpretation of experimental results, the atomistic simulations of melting and ablation processes in Al and Au are provided. The calculated threshold fluencies for melting and ablation are well consistent with measured ones. [ABSTRACT FROM AUTHOR]

The interaction of radiation of a picosecond X-ray laser (wavelength λ = 13.9 nm) with targets made of a thick gold film has been studied theoretically and experimentally. It has been shown experimentally that the action of individual X-ray laser pulses with a fluence of F ≈ 21 mJ/cm initiates the nanostructuring of the gold surface. Explicitly taking into account the electron subsystem, we have proposed an atomistic model of ablation that makes it possible to adequately describe the experimental results. The atomistic simulation involves the ion-ion potential depending on the electron temperature T. The use of such a potential makes it possible to take into account an increase in the pressure in the system with increasing T and to reveal two laser ablation mechanisms. [ABSTRACT FROM AUTHOR]

CeO2– xFe2O3 ( x = 0.026–0.214) solid solutions with different Ce:Fe mole ratios (Ce:Fe = 9.5:0.5–7.0:3.0) were prepared as reactive ceramics with the combustion method for solar hydrogen production. The prepared CeO2– xFe2O3 solid solutions were characterized by X-ray diffractometry, ICP atomic emission spectrometry, and Mössbauer spectroscopy. Two-step water-splitting reaction with the CeO2– xFe2O3 solid solution proceeded at 1,673 K for the O2-releasing reaction and at 1,273 K for the H2-generation reaction by irradiation of an infrared imaging lamp as a solar simulator. The amounts of H2 gas evolved in the H2-generation reaction with CeO2– xFe2O3 solid solutions were 0.97–1.8 cm3/g, the evolved H2/O2 ratio was approximately equal to 2 of the stoichiometric value. The amounts of H2 and O2 gases were independent of the Ce:Fe mole ratio in the CeO2– xFe2O3 solid solution. It was suggested that the O2-releasing and H2-generation reactions with the CeO2– xFe2O3 solid solution were repeated with the reduction and oxidation of Ce4+–Ce3+ enhanced by the presence of Fe3+–Fe2+. [ABSTRACT FROM AUTHOR]

We have succeeded in developing a laser-pumped X-ray laser with full spatial coherence at 13.9 nm. The X-ray laser beam with a very small divergence of 0.2 mrad was generated from double target experiments, where a seeding light from the first laser medium was amplified in the second laser medium. The observed divergence was close to the diffraction limit value within a factor of two. The seeding light was amplified in the second medium without refraction influence and the gain coefficient was 7.9 cm-1. From the measurement of visibility, it was found that the spatial coherent length was longer than the beam diameter. [ABSTRACT FROM AUTHOR]

.Irradiation is suspected to injure inflammatory cells, such as neutrophils and mononuclear phagocytes, cells known to contribute to the development of acute lung injury (ALI). This study examined whether preexposure to x-ray irradiation modifies ALI induced by E. coli injected intravenously in guinea pig. Thirty animals were divided into two control and two irradiated subgroups: the first control group received saline only (n = 8), and the second control group received E. coli, 2 × 10[sup 9] /kg body weight, suspended in saline (n = 6), IV. The first irradiated group received a single 12-Gy dose + saline (n = 6), and the second irradiated group received a single 12-Gy dose + E. coli (n = 10). The lung wet-to-dry-weight ratio (W/D) and [sup 125] I-albumin lung tissue/plasma ratio (T/P) were measured as markers of lung injury. W/D was significantly higher in the control E. coli group than in the other groups. T/P in the control E. coli group was also increased compared with T/P measured in the other groups. In the control E. coli group, a marked increase in bronchoalveolar lavage (BAL) neutrophils was observed compared with the control saline group. However, no significant difference in BAL neutrophil counts was observed between the control and irradiated E. coli groups. In contrast, BAL macrophages were significantly reduced in the irradiated E. coli groups compared with the control E. coli group. These findings suggest that x-ray irradiation attenuates E. coli–induced ALI in guinea pigs, an effect explained, at least in part, by a reduction in the number of alveolar macrophages. [ABSTRACT FROM AUTHOR]

Nanocrystalline Fe-M-C, Co-M-C, and Ni-M-C (M = group IVa-VIa metals) films in which extremely fine M-carbide particles are dispersed were prepared by annealing sputter-deposited amorphous alloy films. Of these films, the Fe-M-C and Co-M-C films exhibited good soft magnetic properties. These soft magnetic properties were maintained after annealing at elevated temperatures, because carbide particles dispersed in the films considerably retard the grain growth of Fe-rich or Co-rich nanocrystallites. Films containing Ta or Hf exhibit particularly high thermal stability (around 1000 K). On the other hand, Zr and Hf are suitable for obtaining high saturation magnetization, Is, because the amount of these elements needed for amorphization is less than other M elements. The highest Is of films containing Zr or Hf was 1.7 T for Fe-M-C and 1.6 T for Co-M-C films. Because the magnetostriction of Fe-M-C films is dominated primarily by the C concentration dissolved into Fe, zero-magnetostrictive films can easily be attained by controlling the C to M ratio or annealing conditions. In addition to the good performance of Fe-Hf-C films, a higher Is value of 2.0 T was achieved by multilayering the Fe-Hf-C with Fe, and improved frequency characteristics of permeability as well as higher thermal stability by about 100 K was achieved by Si additions without sacrificing other properties. These carbide-dispersed nanocrystalline films are suitable for use in high-density magnetic recording heads fabricated by glass bonding processes. [ABSTRACT FROM AUTHOR]

In the present study, an attempt was made to clarify whether ANP molecular forms in the plasma of severe congestive heart failure patients differ from those in healthy persons and whether ANP molecular forms in the plasma of the patients were changed by successful treatment of cardiac disease. Twenty patients with congestive heart failure were treated at Kitasato University Hospital. They were classified as class III or IV by New York Heart Association criteria at the time of admission. Plasma ANP concentrations decreased after treatment from 356 ± 58.2 to 72.3 ± 14.8 pg/ml. The gel permeation chromatograms from the plasma of healthy persons showed low, or low and high molecular weight ANP peaks which correspond to the elution positions of authentic α-ANP or ribonuclease A (mol.wt., 13.7 kdalton). In patients with severe congestive heart failure at a severe stage, middle molecular weight ANP consisted with the elution position of authentic β-ANP was particularly noted in addition of low and high molecular weight ANP peaks. This middle molecular weight peak disappears in most of cases by successful treatment. Molecular forms in the plasma obtained from the coronary sinus and the inferior or superior vena cava were essentially the same. These results indicate that the middle molecular weight ANP supposed as β-ANP may particularly be secreted in severe congestive heart failure patients. [ABSTRACT FROM AUTHOR]

We have measured temporal durations of Ni-like transient collisional excitation X-ray lasers (4d → 4p, J = 0 → 1) using a high-speed X-ray streak camera coupled with a flat field grating spectrometer. The pumping laser pulse consisted of a 400-ps prepulse and a 4.8-ps main pulse derived from a Nd:glass laser system with chirped pulse amplification. A quasi-traveling-wave pumping using a six-step mirror was adopted to synchronize the X-ray laser pulse and the onset of gain in a plasma medium. The X-ray laser outputs from three different materials, silver (Z = 47), palladium (Z = 46) and molybdenum (Z = 42), showed that the X-ray laser duration became shorter as the atomic number decreased. [ABSTRACT FROM AUTHOR]

We report, for the first time, that the energy of femtosecond optical laser pulses, E, with relativistic intensities I > 1021 W/cm2 is efficiently converted to X-ray radiation, which is emitted by 'hot' electron component in collision-less processes and heats the solid density plasma periphery. As shown by direct high-resolution spectroscopic measurements X-ray radiation from plasma periphery exhibits unusual non-linear growth ~E4-5 of its power. The non-linear power growth occurs far earlier than the known regime when the radiation reaction dominates particle motion (RDR). Nevertheless, the radiation is shown to dominate the kinetics of the plasma periphery, changing in this regime (now labeled RDKR) the physical picture of the laser plasma interaction. Although in the experiments reported here we demonstrated by observation of KK hollow ions that X-ray intensities in the keV range exceeds ~1017 W/cm2, there is no theoretical limit of the radiation power. Therefore, such powerful X-ray sources can produce and probe exotic material states with high densities and multiple inner-shell electron excitations even for higher Z elements. Femtosecond laser-produced plasmas may thus provide unique ultra-bright X-ray sources, for future studies of matter in extreme conditions, material science studies, and radiography of biological systems. [ABSTRACT FROM AUTHOR]