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21.
Maiko Shigeno 《Mathematical Programming》2006,107(3):439-459
This paper deals with a generalized maximum flow problem with concave gains, which is a nonlinear network optimization problem.
Optimality conditions and an algorithm for this problem are presented. The optimality conditions are extended from the corresponding
results for the linear gain case. The algorithm is based on the scaled piecewise linear approximation and on the fat path
algorithm described by Goldberg, Plotkin and Tardos for linear gain cases. The proposed algorithm solves a problem with piecewise
linear concave gains faster than the naive solution by adding parallel arcs.
Supported by a Grant-in-Aid for Scientific Research (No. 13780351 and No.14380188) from The Ministry of Education, Culture,
Sports, Science and Technology of Japan. 相似文献
22.
Nobuhito Imanaka Toshiyuki Masui Yuhei Mayama Kazuhiko Koyabu 《Journal of solid state chemistry》2005,178(11):3601-3603
Crystalline yttrium oxycarbonate, Y2O2CO3, was synthesized by our original flux method using the 0.476Li2CO3-0.270Na2CO3-0.254K2CO3 eutectic mixture at 450 °C. The oxycarbonate was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier-transfer infrared spectroscopy (FT-IR). The Y2O2CO3 prepared by the flux method was a crystalline single phase of hexagonal rare earth oxycarbonate (type-II). This is the first report on the single-phase synthesis of crystalline hexagonal type-II Y2O2CO3. 相似文献
23.
This communication presents studies that illustrated nitroso Diels-Alder adduct has been obtained in uniformly high enantioselectivity via a tandem nitroso aldol/Michael reaction using an amine catalyst. The regiochemical outcome of this construction is documented to be the opposite to that of the normal nitroso aldol reaction, which has been determined by X-ray analysis. The reaction of the enone with silver-BINAP catalyst has also been investigated in conjunction with the control of regiochemistry in a stepwise process. 相似文献
24.
Hitoshi Ito Yumi Ohki Yuhei Watanabe Hiromi Sunaga Isao Ishigaki 《Radiation Physics and Chemistry》1993,42(4-6):597-600
Relative sensitivities of endospores of Bacillus pumilus E601, B. subtilis IAM1069, B. megaterium S31 and B. brevis S5 to gamma rays, converted X rays (bremsstrahlung) and electron beams were examined in order to estimate the conditions in which converted X rays kill Bacillus spores. The radiation sensitivities to gamma rays and electron beams of each strain dried on glass fiber filter without additives were found to be almost equivalent, and D values were obtained as follows: 1.5–1.6 kGy for B. pumilus, 1.4–1.5 kGy for B. subtilis, 1.9–2.0 kGy for B. megaterium and 1.6–2.0 kGy for B. brevis. The radiation sensitivities of endospores of each strain to electron beams were slightly lower than those to gamma rays in the dry condition with additives of 2% peptone + 1 % glycerin on glass fiber filters. The increase of radiation resistance in the presence of additives was also observed with X rays, and it was on an intermediate level between those with gamma rays and electron beams. In the dry condition using cellulose filter paper, only the radiation resistances of B. megaterium and B. brevis in the presence of additives B. megaterium and B. brevis in the presence of additives were increased. 相似文献
25.
Isao Kaetsu Fumio Yoshii Yuhei Watanabe 《Journal of polymer science. Part A, Polymer chemistry》1978,16(10):2645-2650
Radiation-induced polymerization of glass-forming monomers such as 2-hydroxyethyl methacrylate and glycidyl methacrylate under high pressure was studied. The glass transition temperature of these monomers was heightened by increased pressure. The temperature dependence of polymerizability showed a characteristic relation; similar to those in supercooled-phase polymerization under normal pressure, that had a maximum at Tv which shifted to higher levels of temperature as well as to Tg under high pressure. Polymerizability in the supercooled state also increased under increased pressure. 相似文献
26.
Dr. Masanori Shigeno Kazutoshi Hayashi Dr. Kanako Nozawa-Kumada Prof. Dr. Yoshinori Kondo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(24):6077-6081
The organic superbase tBu-P4 catalyzes methoxy-alkoxy exchange reactions on (hetero)arenes with alcohols. The catalytic reaction proceeded efficiently with electron-deficient methoxy(hetero)arenes as well as with a variety of alcohols, including 3-amino-1-propanol, β-citronellol, menthol, and cholesterol. An intramolecular version of this reaction furnished six- and seven-membered ring compounds. 相似文献
27.
Dr. Masanori Shigeno Kazuya Hanasaka Keita Sasaki Dr. Kanako Nozawa-Kumada Prof. Dr. Yoshinori Kondo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(13):3235-3239
We herein demonstrate that the combination of LiO-tBu, CsF, and [18]crown-6 efficiently promotes the direct C−H carboxylation of electron-rich heteroarenes (benzothiophene, thiophene, benzofuran, and furan derivatives). A variety of functional groups, including methyl, methoxy, halo, cyano, amide, and keto moieties, are compatible with this system. The reaction proceeds via the formation of a tert-butyl carbonate species. 相似文献
28.
Gururaj M. ShivashimpiShyam S. Pandey Rie WatanabeNaotaka Fujikawa Yuhei OgomiYoshihiro Yamaguchi Shuzi Hayase 《Tetrahedron letters》2012,53(40):5437-5440
Aiming toward the development of far-red sensitive organic dyes, unsymmetrical squaraine dye bearing direct cyanoacrylate functionalized indole ring has been synthesized and characterized along with its utilization as photosensitizer for dye-sensitized solar cells. Upon dye-sensitized solar cell fabrication, this sensitizer exhibits its potentiality as a good far-red sensitive dye having photoconversion efficiency of 5.03% under the simulated solar irradiation at AM 1.5 conditions. This opens up further possibility to design efficient far-red sensitive dyes by judicious implementation of suitable donor moieties with extended π-conjugation. 相似文献
29.
Masahiro Kikuchi Mohammad S. Hussain Norio Morishita Mitsuko Ukai Yasuhiko Kobayashi Yuhei Shimoyama 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(1):310-313
An electron spin resonance (ESR) spectroscopic study of radicals induced in irradiated fresh mangoes was performed. Mangoes in the fresh state were irradiated with γ-rays, lyophilized and then crushed into a powder. The ESR spectrum of the powder showed a strong main peak at g = 2.004 and a pair of peaks centered at the main peak. The main peak was detected from both flesh and skin specimens. This peak height gradually decreased during storage following irradiation. On the other hand, the side peaks showed a well-defined dose–response relationship even at 9 days post-irradiation. The side peaks therefore provide a useful means to define the irradiation of fresh mangoes. 相似文献
30.
Shimoyama Y Ukai M Nakamura H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(4):888-890
We revealed free radicals in wheat flour before and after gamma-ray irradiation and their thermal behavior during heat-treatment using electron spin resonance (ESR) spectroscopy. The ESR spectrum of wheat flour before irradiation consists of a sextet centered at g = 2.0 and a singlet signal at the same g-value position. The first one is attributable to a signal with hyperfine (hf) interactions of Mn2+ ion (hf constant: 7.4 mT). The second is originated from carbon-centered radical. Upon gamma-ray irradiation, however, a new signal with two triplet lines at the low and high field ends was detected in wheat flour on top of the Mn2+ sextet lines. We analyzed the triplet ESR lines as powder spectra (rhombic g-tensor symmetry) with nitrogen (14N) hyperfine interactions. This indicates that a new organic radical was induced in the conjugated protein portion of wheat flour by the gamma-ray irradiation. Intensity of the organic free radical at g = 2.0 detected in irradiated wheat flour increased monotonically by the thermal treatment. The analysis of the time-dependent evolution and decay process based on the theory of transient phenomena as well as the nonlinear least-squares numerical method provided a unique time constant for the radical evolution and decay in wheat flour during the heat-treatment. 相似文献