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51.
52.
Masaru Sakai Shuji Mononobe Shusaku Akiba Akifumi Matsuda Wakana Hara Mamoru Yoshimoto Toshiharu Saiki 《Optical Review》2006,13(4):266-268
We demonstrated a contrast enhancement in a near-field scanning optical microscope (NSOM) by optical interference with an
aperture probe in reflection (illumination-collection) mode operation. We observed a NiO film deposited on a sapphire substrate
and clearly visualized 2-nm-deep nano-channel structures on the surface of the film. The reflection NSOM enhanced by optical
interference is quite a promising instrument for high-resolution optical detection and estimation of low-contrast nanostructures. 相似文献
53.
54.
N. Aoi K. Yoneda H. Miyatake H. Ogawa Y. Yamamoto E. Ideguchi T. Kishida T. Nakamura M. Notani H. Sakurai T. Teranishi H. Wu S. S. Yamamoto Y. Watanabe A. Yoshida M. Ishihara 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(2):253-255
Experimental studies of β-decay measurements of the neutron drip line nuclei 11Li and 14Be are presented. β- decay schemes of these nuclei are determined by measuring β-rays, delayed neutrons and γ-rays in triple coincidence. The decay schemes of both 11Li and 14Be associated with single neutron emission are unambiguously determined. New levels in their daughter nuclei, 11Be and 14B, are found. In addition, the deduced level scheme of 14B indicates the lowering of 2s 1/2 single neutron orbital with respect to 1p 1/2 orbital in the N=9 isotones. Such behavior is known to exist in N=7. 相似文献
55.
Ferricyanide oxidation of the dianions of phenolic β-diketones effects intramolecular phenoxy-enoxy radical coupling to form spiro systems derived from C-C bond formation or to the phenolic oxygen. 相似文献
56.
Yoshiki Katayama Ryuji Fukuda Toshiharu Iwasaki Kazuhide Nita Makoto Takagi 《Analytica chimica acta》1988
New crown ether dyes carrying two pendent anionic side-arms were synthesized for the extraction-spectrophotometry of alkaline earth metal ions. In the extraction of alkaline earth metal ions by these dianionic reagents, size recognition by the crown ether ring was more remarkable than in the case of alkali metal ion extraction by a similar type of monoanionic reagents. Dramatic changes in metal selectivity were observed when the nature of the anionic side-arm was changed while the crown ether skeleton was kept the same. The structure/selectivity relationship is discussed in terms of “chelate” and “intramolecular ion-pair” formation. Typically, when the basicity of the pendent anions was relatively high and a six-membered chelate was structurally possible for the pendent anions and the crown-bound metal, the extraction of calcium was favored by up to a factor of 3000 in the ratio of the Ca/Ba extraction constants for reagents of the diaza-18-crown-6 type. In contrast, the reagents which had pendent anions with only poor coordination ability for metal ions seemed to form complexes of the ion-pair type, and calcium ion was 105 times less extractable than barium ion for the same diaza-18-crown-6-skeleton. Strontium ion seemed to be extracted most effectively when the extracted complex assumed properties intermediate between the chelate and intramolecular ion-pair. 相似文献
57.
Ultrasonic speeds u in {(1?x)C6H6 + xC6H5NO2} were measured by a fixed-path pulse technique at 293.15, 303.15, and 313.15 K under pressures up to 30 or 200 MPa with an observed error of less than 0.3 per cent. Curves of u(x) change smoothly in the benzene-rich region. But near x = 0.7, u(x) apparently deviates from a smooth curve, and the apparent gap becomes progressively greater as the temperature is reduced or the pressure is raised. From the experimental values, densities, isentropic compressibilities, and expansivities were calculated at high pressures. These quantities also show unusual behavior with x similar to that of u. 相似文献
58.
Toshiharu Kawai 《General Relativity and Gravitation》1986,18(10):995-1018
We develop a gauge theory of gravity on the basis of the principal fiber bundle over the four-dimensional space-timeM with the covering groupP¯
0
of the proper orthochronous Poincaré group. The field components
are constructed with the connection coefficients
,
and with a Higgs-type field. A Lorentz metricg is introduced with
, which are then identified with the components of duals of the Vierbein fields. Associated with there is a spinor structure onM. For Lagrangian densityL, which is a function of
,
,, matter field , and oftheir first derivatives, we give the conditions imposed by the requirement of the
gauge invariance. The Lagrangian densityL is restricted to be of the formL =L
tot
(, T
klm
,R
klmn
,
k
, ), in whichT
klm
,R
klmn
are the field strengths of
,
, respectively. Identities and conservation laws following from the
gauge invariance are given. Particularly noteworthy is the fact that the energy momentum conservation law follows from theinternal translational invariance. The field equation of is automatically satisfied, if those of
and of are both satisfied. The possible existence of matter fields with intrinsic energy momentum is pointed out. When is a field with vanishing intrinsic energy momentum, the present theory practically agrees with the conventional Poincaré gauge theory of gravity, except for the seemingly trivial terms in the expression of the spin-angular momentum density. A condition leading to a Riemann-Cartan space-time is given. The field holds a key position in the formulation. 相似文献
59.
A simple synthetic method for macrocyclic ketones based on intramolecular alkylation of carbanion, generated from protected cyanohydrin is reported. Subsequent mild treatment with acid and base of the cyclized products leads to macrocyclic ketones in high yields. The reaction is rapid and irreversible, and hence required short reaction time. The method was successfully applied to the syntheses of cyclohexadecanone and trans-2-cyclopentadecenone as a precursor of (±)-muscone and exaltone. 相似文献
60.
Cosimo Altomare Pierre-Alain Carrupt Nabil El Tayar Bernard Testa Toshiharu Nagatsu 《Helvetica chimica acta》1991,74(2):290-296
A number of isomers and analogs of the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) were examined for their lipophilic behavior. Their partition coefficients in the 1-octanol/H2O system were measured by centrifugal partition chromatography (CPC), which, being much faster and markedly more precise than the classical shake-flask method, proved a very promising alternative for assessing lipophilicity. A smaller-than-expected lipophilicity was shown by the ortho-isomer of MPP+ (M2PP+) and is explained in terms of electronic effects and rigidity, as revealed by UV and NMR spectroscopy, and conformational analysis. Implications of lipophilicity in modulating the in vivo dopaminergic neurotoxicity of the examined compounds are also discussed. 相似文献