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991.
Abstract Effect of high pressure on the crystal structure of rhombohedral NaNO3 was investigated by X-ray diffraction of single crystals mounted in a miniature diamond-anvil cell on synchrotron radiation source. Diffraction intensity measurements were made at three pressures across a suggested transition pressure 4.3 GPa. No change was observed in an overall distribution of reflections in the reciprocal space with increasing pressure, but there was a systematic variation in diffraction intensity for particular groups of reflections. An analysis based on the structure factor calculation showed that a structure change induced by pressure is mainly a rotation of the nitrate groups in the alternate layers along the threefold axis in opposite directions. Least-squares refinement of the atomic positional parameters yielded the angle of the rotation to be 4.3 and 7.0 deg at pressures of 4.4 and 5.0 GPa, respectively. It has also been shown that the positions of the sodium and nitrogen atoms are slightly displaced along the axis, resulting in the formation of dipoles in the high pressure phase. 相似文献
992.
Abstract Powdered samples of TiO0.82, TiO1.04 and TiO1.25 having the cubic rocksalt-type structure with high concentration of vacancies randomly distributed were held at combined conditions of high pressure, ranging from 1 GPa to 8 GPa, and high temperature, ranging from 973 K to 1173 K, and structural changes occurring were investigated by synchrotron radiation diffraction at the conditions and by conventional X-ray diffraction after the samples were brought back to ambient condition. Pressure has been shown to suppress formation of ordered arrangements of vacancies in all the samples and lead to precipitation of a hexagonal δ-Ti3O2 in TiO0.82 and TiO1.04 and precipitation of a corundum-type Ti2O3 in TiO1.25. Irreversible change in the lattice parameter of the remaining rocksalt-type structure has been observed which is due to partial annihilation of vacancies under pressure. 相似文献
993.
Tetsuya Kawakubo 《Molecular Crystals and Liquid Crystals》2013,570(1):163-177
Biphenyl single crystals irradiated with γ rays at liquid nitrogen temperature have been investigated by electron paramagnetic resonance and optical absorption experiments. EPR spectra at room temperature exhibit a triplet characteristic separated by 39 gauss and each line of the triplet further splits to a triplet. The main triplet has been interpreted as being caused by hydrogen added biphenyl radicals. The splitting of each line of the main triplet is consistent with the calculated splittings of 2-hydro-biphenyl radicals and 4-hydro-biphenyl radicals. The presence of 3-hydro-biphenyl radicals could not be judged from the EPR spectra due to the broadness of the lines. In the optical absorption spectra at low temperature, obtained with the light polarized to the a-, b- and c'-axes of the crystals, nine bands were detected. Transition energies were calculated using SCF-C1 molecular orbital theory for the three kinds of the hydrogen added biphenyl radicals. By comparing the experimental spectra with the theoretical transitions of the three kinds of radicals, the bands at 666 nm and 424 nm have been assigned to the transitions of 2-hydro-biphenyl radicals, the 660 nm band to that of 3-hydro-biphenyl radicals, and the bands at 604 nm and 598 nm to the ones of 4-hydro-biphenyl radicals. The decays of these radicals at room temperature are very similar and upon annealing a new absorption band appears at 462 nm. 相似文献
994.
Tetsuya Kawakubo 《Molecular Crystals and Liquid Crystals》2013,570(1-2):11-24
Pyrene single crystals irradiated with γ rays at room temperature have been investigated by electron paramagnetic resonance and optical absorption experiments. EPR spectra exhibit a triplet characteristic and each line of the triplet shows characteristic features with rotations of the crystals in a magnetic field. From analyses of these spectra the presence of two kinds of hydrogen added pyrene radicals, 3-H2-pyrene and 2-H2-pyrene radicals, is concluded. In the optical absorption spectrum nine main absorption bands have been detected. These absorption bands are compared with the theoretically calculated transition energies with SCF-CI molecular orbital calculations for 3-H2-pyrene and 2-H2-pyrene radicals. Reasonable correspondences are obtained between theoretical values and the experimental spectrum. 相似文献
995.
Iwasaki H Morimoto K Koh M Okamura T Wakasa K Wakasa T Kinoshita H 《Magnetic resonance imaging》2004,22(2):285-290
A 63-year-old woman was found to have a left breast mass after quadrantectomy and radiation for bilateral breast cancer on postoperative cyclic examination. Intramammary recurrence could not be excluded by physical examination, mammography, or ultrasound examination. MR imaging with fat suppression technique revealed an oil-containing lesion, indicating fat necrosis. It was confirmed histologically that the mass-forming lesion included no cancer tissue. MR imaging with fat suppression technique appears to be a promising method for identification of postoperative mass lesions of the breast. 相似文献
996.
997.
Kentaro Wakui Kazuhiro Hayasaka Tetsuya Ido 《Applied physics. B, Lasers and optics》2014,117(3):957-967
Vacuum ultraviolet (VUV) radiation around 159 nm is obtained toward direct excitation of a single trapped \(^{115}\hbox {In}^{+}\) ion. An efficient fluoride-based VUV output coupler is employed for intracavity high-harmonic generation of a Ti:S oscillator. Using this coupler, where we measured its reflectance to be about 90 %, an average power reaching 6.4 \(\upmu\) W is coupled out from a modest fundamental power of 650 mW. When a single comb component out of 1.9 \(\times\) 10 \(^{5}\) teeth is resonant to the atomic transition, 100s of fluorescence photons per second will be detectable under a realistic condition. 相似文献
998.
Tetsuya Shimogaki Kota Okazaki Kota Yamasaki Koshi Fusazaki Yasuaki Mizokami Norihiro Tetsuyama Mitsuhiro Higashihata Hiroshi Ikenoue Daisuke Nakamura Tatsuo Okada 《Applied Physics A: Materials Science & Processing》2014,117(1):269-273
We have been establishing the technique of fabricating spherical semiconductor microcrystals with suitable diameters for whispering gallery mode (WGM) lasing. Concretely, semiconductor microspheres were synthesized by ablating various semiconductor-sintered targets with focused pulsed laser at high fluences. In this report, dependences of fabricated zinc oxide (ZnO) microstructures on laser wavelengths were investigated. Lasing characteristics and photoluminescence of ZnO microspheres were determined, and photoluminescence of Sb-doped ZnO microspheres were determined. Additionally, it was also found that Sb-doped ZnO and aluminum nitride microspheres can be similarly synthesized. By developing this method, which does not require complex processing, it is expected that efforts in the application of WGM lasing are accelerated in many kinds of semiconductors. 相似文献
999.
Yukako Takizawa Yoichi Kitagawa Tetsuya Matsumoto Akio Mizuno Takaharu Sato Osamu Matoba 《Optical Review》2011,18(1):187-190
Volume holographic optical element (VHOE) for imaging under white light illumination is integrated with imaging elements and
background noise reduction filter. An integrated VHOE and the band pass filter which is optimized to the VHOE can develop
the optical setup for a wearable eye-gaze detection system. An integrated VHOE is fabricated in photopolymer and then the
effects of noise reduction filters as a function of the direction of the incident plane wave into an image sensor are evaluated.
Experimental results show that the background noise reduction filter should be designed to reduce the incident light with
wide direction of the transmitted light. 相似文献
1000.
Masashi Monobe Hiroyuki A. Sakaue Daiji Kato Izumi Murakami Hirohisa Hara Tetsuya Watanabe Nobuyuki Nakamura 《X射线光谱测定》2020,49(4):511-514
We present extreme ultraviolet spectra of 3s3p–3s3d transitions in Fe14+ observed with a compact electron beam ion trap. The contributions of indirect excitation via a metastable state and resonant excitation are studied by observing the electron energy dependence of the spectra for the energy range of 60–210 eV. The results indicate that the 3s3d 1D2 level is directly excited from the 3s2 ground state whereas the 3s3d 3D3 level has a large contribution of the indirect excitation via the 3s3p 3P2 metastable state. Comparisons with the theoretical excitation cross sections including MNn resonant excitations show good qualitative agreement with the experimental results for the electron energy dependent features. 相似文献