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排序方式: 共有128条查询结果,搜索用时 15 毫秒
21.
T. Okato P.A. Atanasov M. Obara 《Applied Physics A: Materials Science & Processing》2003,77(3-4):395-398
Thin-film Nd-doped potassium gadolinium tungstate (Nd:KGW or KGd(WO4)2) waveguides are deposited on (1102)sapphire or (100)YAG substrates by KrF laser ablation of potassium-rich ceramic targets in Ar and O2. The dependence of the stoichiometry, crystallinity and waveguide properties of the films on the environmental gas pressure and substrate temperature is studied. Highly textured crystalline (110) KGW films are grown. An optical waveguide loss as low as 3 dB/cm is obtained for the films grown in Ar. The as-grown films are optically active. Upon annealing at 900 °C in air, the crystallinity and the properties of the emission spectra are dramatically improved. PACS 81.15.Fg; 42.70.Hj; 78.20.Ek 相似文献
22.
T. Ueda T. Obara A. Imamura Ya. Sato Yo. Kakuta 《Mechanics of Composite Materials》1996,32(2):107-112
Experimental results of model speciments in which FRP rods fractured due to local deformation at a crack intersection in a concrete member were analyzed by a 3D nonlinear finite element method in which orthogonal anisotropy of the FRP rod was considered. The analytical results indicated that accurate prediction of shear modulus of the FRP rod and size of concrete wedge cone failure around the FRP rod was significant to predict deformation and fracture of the FRP rod. FRP rods as reinforcement in concrete members, the small shear modulus, because of the orthogonal anisotropy and the wedge cone failure, may prevent the FRP rod from fracturing at a very low tensile stress due to the local deformation at the crack intersection.Presented at the Ninth International Conference on the Mechanics of Composite Materials, Riga, October, 1995.Published in Mekhanika Kompozitnykh Materialov, Vol. 21, No. 2, pp. 158–166, March–April, 1996. 相似文献
23.
Yutaka T Obara S Ogawa S Nozaki K Ikeda N Ohno T Ishii Y Sakai K Haga MA 《Inorganic chemistry》2005,44(13):4737-4746
A series of novel emissive Ir(III) complexes having the coordination environments of [Ir(N--N--N)2]3+, [Ir(N--N--N)(N--N)Cl]2+, and [Ir(N--N--N)(N--C--N)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, N--N--N), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, N--C--N), 4'-(4-methylphenyl)-2,2':6',2' '-terpyridine (ttpy, N--N--N), and 2,2'-bipyridine (bpy, N--N) have been synthesized and their photophysical and electrochemical properties studied. The Ir(III) complexes exhibited phosphorescent emissions in the 500-600 nm region, with lifetimes ranging from approximately 1-10 micros at 295 K. Analysis of the 0-0 energies and the redox potentials indicated that the lowest excited state of [Ir(L1)(L2)]2+ possessed the highest contribution of 3MLCT (MLCT = metal-to-ligand charge transfer) among the Ir(III) complexes, reflecting the sigma-donating ability of the tridentate ligand, ttpy < L1 < L2. The emission quantum yields (phi) of the Ir(III) complexes ranged from 0.037 to 0.19, and the highest phi value (0.19) was obtained for [Ir(L1)(bpy)Cl]2+. Radiative rate constants (k(r)) were 1.2 x 10(4) s(-1) for [Ir(ttpy)2]3+, 3.7 x 10(4) s(-1) for [Ir(L1)(bpy)Cl]2+, 3.8 x 10(4) s(-1) for [Ir(ttpy)(bpy)Cl]2+, 3.9 x 10(4) s(-1) for [Ir(L1)2]3+, and 6.6 x 10(4) s(-1) for [Ir(L1)(L2)]2+. The highest radiative rate for [Ir(L1)(L2)]2+ with the highest contribution of 3MLCT could be explained in terms of the singlet-triplet mixing induced by spin-orbit coupling of 5d electrons in the MLCT electronic configurations. 相似文献
24.
Daiki Obara 《代数通讯》2013,41(5):1724-1761
We consider quiver algebras A q over a field k defined by two cycles and a quantum-like relation depending on a nonzero element q in k, and describe the minimal projective bimodule resolution of A q . In particular, in the case q = 1, we determine the Hochschild cohomology ring of A 1 and show that it is a finitely generated k-algebra. Moreover the Hochschild cohomology ring of A 1 modulo nilpotence is isomorphic to the polynomial ring of two variables. 相似文献
25.
Tatsunori Sakano Hiroki Fukuoka Yoshihiro Yata Toshiharu Saiki Minoru Obara 《Applied Physics A: Materials Science & Processing》2008,93(3):697-703
We employed epi-GaN substrates for ZnO film growth, and studied the deposition and post-annealing effects. ZnO films were
grown by pulsed laser deposition (PLD) method. The as-grown films were annealed for one hour under atmospheric pressure air.
ZnO morphologies after annealing were investigated and the post-annealed ZnO films grown at T
g
=700oC have very smooth surfaces and the rms with roughness is about 0.5 nm. Finally, ZnO post-annealed buffer layer was inserted
between ZnO epilayer and GaN/sapphire substrates. It is confirmed by AFM that growth temperature of 700oC helps the films grow in step-flow growth mode. It is observed by cathode luminescence spectrum that the ZnO film grown at
700oC has very low visible luminescence, indicating the decrease of the deep level defects. It is also revealed by Hall measurements
that carrier concentration is decreased by increasing the growth temperatures. It is suggested that low temperature buffer
layer growth and post-annealing technique can be used to fabricate ZnO hetero-epitaxy. 相似文献
26.
This paper presents a new method of multispectral hyperbolic incoherent holography in which a hyperbolic volume interferogram was directly measured by an appropriate designed interferometer. This method enables to obtain a set of spectral components of three-dimensional images and continuous spectra for spatially incoherent, polychromatic objects. We introduced a calibration method of a phase aberration of the interferometer. The spectral resolution and spatial resolutions are investigated based on analytical solution of impulse response function of hyperbolic holography. From experimental results and theoretical predictions, the validity of the calibration method was confirmed. Experimental results agree with the theoretical ones. Consequently, the retrieved images obtained by the method are shown to demonstrate the performance of the method. 相似文献
27.
Daiki OBARA 《Frontiers of Mathematics in China》2016,11(4):1003-1015
We consider a one point extension algebra B of a quiver algebra A q over a field k defined by two cycles and a quantum-like relation depending on a nonzero element q in k. We determine the Hochschild cohomology ring of B modulo nilpotence and show that if q is a root of unity, then B is a counterexample to Snashall-Solberg’s conjecture. 相似文献
28.
T. Miyanishi Y. Tsunoi M. Terakawa M. Obara 《Applied physics. B, Lasers and optics》2012,107(2):323-332
We present near-field distributions around an isolated 800-nm silica or silicon nanoparticle, and nanoparticle arrays of 800-nm silica or silicon nanoparticles, on a silicon substrate by the finite-difference time-domain method when 800-nm light is irradiated obliquely to the substrate. Nanopatterning mediated with the nanoparticle system is promising for large-area, high-throughput patterning by using an enhanced localized near-field ablation by the nanoscattered light lens effect. The irradiation area cannot be extended for silica nanoparticles, because the optical field enhancement factor is low. Gold nanoparticles can generate highly enhanced near fields, although at present there are no useful ways to arrange the gold nanoparticles on the substrate at a high throughput. Silicon nanoparticles with high dielectric permittivity have optical characteristics of both silica and gold nanoparticles. The particle arrangement on the Si substrate is technically easy using a wet pulling process. From the calculation, high optical field intensity is acquired with oblique s-polarized irradiation to the substrate under silicon nanoparticle arrays, and the intensity is almost the same as that under gold nanoparticle arrays under the same condition. With this method, high-throughput nanopatterning for a large area would be achievable. 相似文献
29.
Targets at various positions in a noise image were detected by the optical matched filtering technique. In this case the thermoplastic optical recorder was used as a matched filter recorder. High accuracy of position detection was obtained, i.e. the position error was 2% or less. 相似文献
30.
N.N. Nedyalkov H. Takada M. Obara 《Applied Physics A: Materials Science & Processing》2006,85(2):163-168
High-energy synchrotron X-ray diffraction and imaging experiments were performed at the Advanced Photon Source on two ancient
Chinese bronzes from the Art Institute of Chicago with the goal to nondestructively study their microstructure. The first
object, a bronze fragment from an early Western Zhou dynasty vessel (Hu, 11th/10th century B.C.), was investigated with spatially-resolved
diffraction to reveal the depth and composition of the surface corrosion layer as well as the composition and grain size of
the underlying bronze core. The second object, a bronze dagger-axe (Ge, 3rd/2nd century B.C.) with a silver-inlaid sheath,
was studied under both diffraction and imaging conditions. It was found to have been cast as a single object, answering longstanding
scholars’ questions on whether the ceremonial object concealed an interior blade.
PACS 81.00; 01.75.+m 相似文献