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121.
Yoshiya ODA 《色谱》2000,18(6)
1 IntroductionMorethanhalfoftheorganiccompoundsmarketedasdrugsareasymmetricmolecules .Theenantiomersofdrugs ,whichhaveachiralcenteroften ,havedifferentpharmacologicalactivityortoxicity ,owingtodifferencesinthebehaviorofenantiomersinvivo .Recently ,enantiom… 相似文献
122.
K. Amemiya H. Takahashi Y. Kajimoto M. Nakazawa H. Yanagie T. Hisa M. Eriguchi Y. Nakagawa T. Majima T. Kageji Y. Sakurai T. Kobayashi T. Konishi K. Hieda N. Yasuda K. Ogura 《Radiation measurements》2005,40(2-6):283-288
In radiation cancer therapies using energetic charged particles such as proton/heavy-ion therapy and boron neutron capture therapy (BNCT), studies on radiation-induced biological response at cellular level are important because the radiation damage from energetic charged particles is highly localized along their paths and the radiation sensitivity is quite different in each cellular organelle. In such studies the information on the position of charged particle impact in biological cells is necessary. A novel method for high-resolution nuclear track mapping in detailed cellular histology has been developed. In this technique, biological specimens mounted on CR-39 plates are exposed to energetic charged particles. The irradiated samples are exposed to UV, and then etched for a short time. Both etch pits of nuclear tracks and relief for transmission UV image of the specimen can be observed on the CR-39 surface with an atomic force microscope (AFM) at about 100 nm resolution. 相似文献
123.
Kazuki Komatsu Koji Munakata Kazuyuki Matsubayashi Yoshiya Uwatoko Yoshihiko Yokoyama Kazumasa Sugiyama 《高压研究》2015,35(3):254-262
Zirconium-based bulk metallic glass (Zr-based BMG) has outstanding properties as a cylinder material for piston-cylinder high pressure apparatuses and is especially useful for neutron scattering. The piston-cylinder consisting of a Zr-based BMG cylinder with outer/inner diameters of 8.8/2.5?mm sustains pressures up to 1.81?GPa and ruptured at 2.0?GPa, with pressure values determined by the superconducting temperature of lead. The neutron attenuation of Zr-based BMG is similar to that of TiZr null-scattering alloy and more transparent than that of CuBe alloy. No contamination of sharp Bragg reflections is observed in the neutron diffraction pattern for Zr-based BMG. The magnetic susceptibility of Zr-based BMG is similar to that of CuBe alloy; this leads to a potential application for measurements of magnetic properties under pressure. 相似文献
124.
D. Miyagi O. Tsukamoto N. Amemiya H. Mukai J. Fujikami K. Hayashi K. Sato 《Physica C: Superconductivity and its Applications》1998,310(1-4):90-94
We measured the AC transport current loss of Bi 2223 multifilament Ag-sheathed tape under DC external magnetic field of 0–0.2 T. There were discrepancies between the measured data and Norris' formula for elliptical model in the range of low value of Ip/Ic (Ip and Ic are peak of the AC transport current and critical current of the tape respectively), while without DC background field, the loss of the tape was close to Norris' formula. Theoretically speaking, even with the DC background field and decreased critical current the AC transport current loss of the tape follows Norris' formula which is derived from the Bean model. When DC background field is applied to the HTS tape, n value of the power law E–J characteristics decreases together with the decrease of Jc. Dependence of the AC transport current loss on the n value was analyzed by numerical calculation. The results show that the loss depends on the n value and that decrease of the n value is one of the causes of the discrepancies between the measured data and Norris' formula. 相似文献
125.
In this paper, we show that a sufficient condition for the delay-independent stabilizability of linear delay systems, which had been obtained by Amemiya et al., is also valid for linear neutral systems with measurable state variables by a new differential-difference inequality.The authors express their appreciation to Professor G. Leitmann for his useful comments. 相似文献
126.
So far a necessary and sufficient condition for the global asymptotic stability of linear mixed monotone delayed differential equation with time varying delay has been presented. However, several basic tools utilized for that proof are not restricted to linear functions. Here it is proved that similar results are obtained for the global asymptotic properties of nonlinear delay differential equation with analogous properties. 相似文献
127.
Shiota H Ano Y Aihara Y Fukumoto Y Chatani N 《Journal of the American Chemical Society》2011,133(38):14952-14955
Although the pioneering example of ortho metalation involving cleavage of C-H bonds was achieved using a nickel complex (Kleiman, J. P.; Dubeck, M. J. Am. Chem. Soc. 1963, 85, 1544), no examples of catalysis using nickel complexes have been reported. In this work, the Ni-catalyzed transformation of ortho C-H bonds utilizing chelation assistance, such as oxidative cycloaddition of aromatic amides with alkynes, has been achieved. 相似文献
128.
Saito N Terakawa R Shigeno M Amemiya R Yamaguchi M 《The Journal of organic chemistry》2011,76(12):4841-4858
Three series of ethynylhelicene oligomers with different side chains were synthesized: (P)-bD-n (n = 2-6) with branched alkyloxycarbonyl side chains; (P)-S-n (n = 2-7) with decylsulfanyl side chains; and (P)-DF-n (n = 4, 6, 8, 10) with alternating decyloxycarbonyl and perfluorooctyl side chains. The double helix formation of these side chain derivatives was compared to that of (P)-D-n with decyloxycarbonyl side chains. CD, UV-vis, and vapor pressure osmometry (VPO) studies showed that (P)-bD-n formed double helices as well as (P)-D-n. CD studies in trifluoromethylbenzene at different temperatures and concentrations indicated that the stability of the aggregate of (P)-bD-6 was similar to that of (P)-D-6. Bulkiness of side chains had little effect on aggregation, which indicated that π-π interactions of the aromatic moiety were essential for double helix formation. (P)-S-n were random coils in all solvents examined except in trifluoromethylbenzene. Whereas (P)-D-7 formed a double helix at 1 × 10(-3) M in toluene, (P)-S-7 was a random coil. This result indicated that the double helix forming ability of (P)-S-n was substantially lower than that of (P)-D-n. Based on the previous observation that (P)-F-n formed a more stable double helix than (P)-D-n, the order of stability may be summarized as follows: (P)-F-n > (P)-D-n and (P)-bD-n >(P)-S-n. The lower stability of (P)-S-n compared to that of (P)-F-n was ascribed to the softness and/or the electron-rich nature at the m-phenylene moiety. (P)-DF-n did not form a stable double helix. It was speculated that a regular alternating arrangement of soft/hard or electron-rich/deficient moieties is important for stable double helix formation. Side chains of ethynylhelicene oligomers can play significant roles in determining the stability of double helices. 相似文献
129.
Ohgushi K Yamamoto A Kiuchi Y Ganguli C Matsubayashi K Uwatoko Y Takagi H 《Physical review letters》2011,106(1):017001
We have successfully synthesized a new rhenium-based hexagonal bronze material, HgxReO3, which exhibits superconductivity with the transition temperature Tc=7.7 K at ambient pressure and 11.1 K at 4 GPa. This compound is a superconductor with the highest Tc among hexagonal bronzes. Moreover, it presents the novel crystallographic feature that (Hg2)2+ polycations, in contrast to monatomic cations in known hexagonal bronzes, are incorporated into open channels. There is evidence that conducting electrons tightly couple with Hg-related phonons. Our results inspire detailed studies on the role of the rattling phonon in the occurrence of superconductivity in the hexagonal bronzes. 相似文献
130.
Yuya Shinohara Akira Watanabe Hiroyuki Kishimoto Yoshiyuki Amemiya 《Journal of synchrotron radiation》2013,20(5):801-804
Combined X‐ray photon correlation spectroscopy (XPCS) and diffracted X‐ray tracking (DXT) measurements of carbon‐black nanocrystals embedded in styrene–butadiene rubber were performed. From the intensity fluctuation of speckle patterns in a small‐angle scattering region (XPCS), dynamical information relating to the translational motion can be obtained, and the rotational motion is observed through the changes in the positions of DXT diffraction spots. Graphitized carbon‐black nanocrystals in unvulcanized styrene–butadiene rubber showed an apparent discrepancy between their translational and rotational motions; this result seems to support a stress‐relaxation model for the origin of super‐diffusive particle motion that is widely observed in nanocolloidal systems. Combined measurements using these two techniques will give new insights into nanoscopic dynamics, and will be useful as a microrheology technique. 相似文献