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21.
22.
Nobuko Takeuchi 《Journal of Geometry》1989,34(1-2):195-200
A sphereM inE
3 is characterized as a simply connected complete smooth surface which contains a circle through each pointp M contained in a normal plane ofM atp.The author would like to thank Professor K. Ogiue for his valuable suggestions. 相似文献
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The structure of senecicannabine(), a new mcrocyclic pyrrolizidine alkaloid isolated from , has been established by chemical study and X-ray analysis. 相似文献
26.
The purpose of this study was to investigate the temperature-induced crystallization and the compactibility of the composite particles containing amorphous lactose and various types of polymers. The composite particles were prepared by spray-drying an aqueous solution of lactose and various types of gel forming water-soluble polymers at various formulating ratios. The stabilizing effect of hydroxypropylcellulose (HPC) and polyvinyl pyrrolidone (PVP) on amorphous lactose in the composite particles was smaller than that of sodium alginate in comparing at the same formulating ratios. The difference in the stability of amorphous lactose in the composite particles was attributed to the difference in the glass transition temperature (Tg) of the composite particles caused by the polymers formulated. The tensile strength of compacted spray-dried composite particles containing the polymers was higher than commercial lactose for direct tabletting (DCL21). The tensile strength of the composite particles was increased with an increase in water content in the particles. The difference in compactibility of the composite particles containing the different amount of polymer and water could be explained by the difference in Tg of the particles. 相似文献
27.
T. Takeuchi Y. Nakano A. Aoki S. Ohmori T. Tsukatani 《Journal of Radioanalytical and Nuclear Chemistry》1987,112(1):259-272
Human hair collected from the mercury, arsenic and cadmium polluted areas has been analysed by instrumental neutron activation method. The concentrations of 27 elements were compared with those of normal Japanese. Correlation coefficients of logarithmic concentrations between the elements were calculated and their significance levels were determined. Factor contribution and factor loadings of the elements were calculated for each factor by making use of principal component analysis. The factor score of each sample was also calculated for each factor to examine the effects of the contamination by heavy metals on individuals. 相似文献
28.
Toru Egawa Yukari Kachi Tsuguhide Takeshima Hiroshi Takeuchi Shigehiro Konaka 《Journal of Molecular Structure》2003,658(3):241-251
The molecular structure and conformation of carvone, a compound with a minty odor, were investigated by means of gas electron diffraction supported by theoretical calculations. Electron diffraction patterns were recorded by heating the nozzle up to 128 °C to obtain enough scattering intensity. The infrared spectrum was also measured by using an absorption cell with a path length of 10 m. The obtained molecular scattering intensities were analyzed with the aid of theoretical calculations and infrared spectroscopy. It was revealed that the experimental data are well reproduced by assuming that carvone consists of a mixture of three conformers that have the isopropenyl group in the equatorial position and mutually differ in the torsional angle around the single bond connecting the ring and the isopropenyl group. It was also found that the puckering amplitude of the ring of carvone is close to those of menthol and isomenthol, a minty compound and its nonminty isomer. The determined structural parameters (rg and ∠α) of the most abundant conformer of carvone are as follows: 〈r(C-C)〉=1.520(3) Å; 〈r(CC)〉=1.360(5) Å; r(CO)=1.225(5) Å; 〈r(C-H)〉=1.104(4)Å; 〈∠CC-C〉=121.1(5)°; 〈∠C-C-C〉=110.4(5)°; ∠C-CO-C=117.1(14)°; 〈∠C-C-H〉=111.1(13)°. Angle brackets denote average values and parenthesized values are the estimated limits of error (3σ) referring to the last significant digit. 相似文献
29.
Hideki Nishimori Masahiro Tatsumisago Tsutomu Minami 《Journal of Sol-Gel Science and Technology》1997,9(1):25-31
Monodispersed silica particles up to ca. 1.2 μm in diameter were prepared by hydrolysis of tetraethoxysilane in the presence
of sodium dodecyl sulfate (SDS). The particle size was increased with an increase of SDS added. The geometrical standard deviation
of the particles was decreased with an increase of SDS. In the earlier reaction stage, double spherical particles by the coalescence
of the particles were frequently observed when large amounts of SDS were added. Particle size was gradually increased after
the coalescence occurred and spherical particles were finally obtained. The results of Nielsen’s chronomal analysis suggest
that the polynuclear layer growth took place after the coalescence of the particles in the presence of larger amount of SDS. 相似文献
30.
H. Kawaguchi S. Kataiwa T. Mita Y. Ohtsuka T. Takeuchi S. Kobayashi 《Colloid and polymer science》1990,268(12):1167-1173
Dichlorophene was used as a model drug. Drug-carrying latex particles were prepared by soap-free emulsion copolymerization of dichlorophene acrylate with some hydrophilic methacrylate comonomers. The comonomers used affected not only the structure and colloidal stability of particles, but also the drug-activity of particles. Preliminary study of the drug activity revealed that highly hydrophilic latex particles were very stable and too inactive to be engulfed by amoebae and kill them. On the contrary, less hydrophilic particles carrying a large amount of drug can be an effective device to release drugs at a moderate rate to fight against extracelluar targets such as parasites. 相似文献