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111.
A proposed structure for the diffusible extracellular factor (DF) of Xanthomonas campestris pv. campestris (Xcc) has been synthesized. Its MS spectrum and biological activity, however, contradict those of the natural product previously reported, suggesting that the structure for DF of Xcc must be reexamined. 相似文献
112.
Hiroshi Yasuoka Susumu Sasaki Takashi Imai Tadashi Shimizu Yutaka Ueda Koji Kosuge 《Phase Transitions》2013,86(4):183-199
The nuclear quadrupole resonance (NQR) technique has been utilized to characterize the local oxygen coordination of inequivalent Cu sites in YBa2Cu3O6+x(0 ≤ x ≤ 0.91). Essentially, four distinct NQR lines which correspond to 2, 3,4 oxygen coordinated Cu sites in the Cu-O chains and 5 oxygen coordinated Cu sites in the Cu-O planes have been observed. The zero-field NQR frequencies of these are centered at about 30.1, 24.0, 22.0 and 31.5 MHz for 63Cu, respectively. For the antiferromagnetic ordered state (x ≤ 0.3), antiferromagnetic nuclear resonance (AFNR) has been observed at 90 MHz with quadrupole splittings associated with the moment-bearing Cu sites in the Cu-O planes. The relative intensities of these resonance lines depend on the oxygen content, and this gives us a microscopic understanding of the Cu chemistry of this system. 相似文献
113.
Toshikatsu Koga Katsutoshi Kanayama Tadanori Watanabe Takashi Imai Ajit J. Thakkar 《Theoretical chemistry accounts》2000,104(5):411-413
Analytical approximations to Hartree–Fock wave functions are constructed using Slater-type functions for the ground states
of all 49 neutral atoms from Cs (Z=55) to Lr (Z=103). The current compilation is more extensive and more accurate than previous ones. The wave functions are available upon
request from the authors or from the Web page http://www.unb.ca/chem/ajit/download.htm on the Internet.
Received: 6 December 1999 / Accepted: 29 February 2000 / Published online: 12 May 2000 相似文献
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Silicon dioxide (SiO2) layers with a thickness more than 10 nm can be formed at ∼120 °C by direct Si oxidation with nitric acid (HNO3). Si is initially immersed in 40 wt.% HNO3 at the boiling temperature of 108 °C, which forms a ∼1 nm SiO2 layer, and the immersion is continued after reaching the azeotropic point (i.e., 68 wt.% HNO3 at 121 °C), resulting in an increase in the SiO2 thickness. The nitric acid oxidation rates are the same for (1 1 1) and (1 0 0) orientations, and n-type and p-type Si wafers. The oxidation rate is constant at least up to 15 nm SiO2 thickness (i.e., 1.5 nm/h for single crystalline Si and 3.4 nm/h for polycrystalline Si (poly-Si)), indicating that the interfacial reaction is the rate-determining step. SiO2 layers with a uniform thickness are formed even on a rough surface of poly-Si thin film. 相似文献
117.
C. P. Slichter S. E. Barrett J. A. Martindale D. J. Durand C. H. Pennington C. A. Klug K. E. O’Hara S. M. DeSoto T. Imai J. P. Rice T. A. Friedmann D. M. Ginsberg 《Applied magnetic resonance》1992,3(3-4):423-448
The authors review and up-date their work on Knight shifts, spin-lattice relaxation, and indirect nuclear spin-spin coupling for YBa2Cu3O7 in the superconducting state. The data are analyzed in particular to show what it may indicate about the orbital and spin pairing of the superconducting state. 相似文献
118.
Temperature sensing using 1.54 μm fluorescence at the transition between the energy levels4I15/2 (ground state) and4I13/2 generated in an erbium-doped fiber with 1.48 μm pumping is proposed. The fluorescence has a peculiar spectral profile that possesses two peaks around 1.530 μm and 1.552 μm wavelengths. The temperature-dependent fluorescence is investigated in the temperature range between -50°C and 90°C. The power ratio between the two peaks increases with an increase in temperature. The sensitivity of the ratio is 0.007/°C on average in the measured temperature range. The total fluorescence power and the absorption loss at λ = 1480 nm in the fiber decrease as the temperature increases. Optical fiber temperature sensing immune from the fluctuation in pumping power can be performed using the peak power ratio and/or the absorption loss. 相似文献
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120.
David Rappaport Hiroshi Imai Godfried T. Toussaint 《Discrete and Computational Geometry》1990,5(1):289-304
We address the problem of connecting line segments to form the boundary of a simple polygon—a simple circuit. However, not every set of segments can be so connected. We present anO(n logn)-time algorithm to determine whether a set of segments, constrained so that each segment has at least one endpoint on the boundary of the convex hull of the segments, admits a simple circuit. Furthermore, this technique can also be used to compute a simple circuit of minimum perimeter, or a simple circuit that bounds the minimum area, with no increase in computational complexity. 相似文献