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81.
Tanaka H Sudo M Hirata M Etoh H Sato M Yamaguchi R Sakai E Chen IS Fukai T 《Natural product communications》2010,5(11):1781-1784
A new biisoflavonoid, biseryvarin A (1a), together with two known compounds were isolated from the roots of Erythrina variegata. The structure of biseryvarin A was established on the basis of spectroscopic evidence. Biseryvarin A is the first dimeric isoflavonoid possessing isoprenoid groups from the genus Erythrina. Biseryvarin A showed low activity against methicillin-resistant Staphylococcus aureus (MRSA). 相似文献
82.
A comparative study of the luminescent properties of Y2O3:Eu3+ phosphor powders and thin films sputtered from targets prepared from combustion synthesized powders is reported. Thin films of (Y0.96Eu0.04)2O3 were deposited on silicon substrates. Films deposited at 600 °C had both monoclinic and cubic phases of Y2O3, which developed to an oriented cubic phase after annealing. Films and powders showed a linear dependence of the intensity of the 5D7→7F2 (611 nm) transition with temperature in the range 26-660 °C with an average rate of change of 1.8×10−4 °C−1. The rate of change appears to be dependent on the Eu3+ concentration. This work shows that these thin films can be used as thermographic phosphors for remote temperature measurements. 相似文献
83.
Junko Morikawa Akihiro OrieYuta Hikima Toshimasa HashimotoSaulius Juodkazis 《Applied Surface Science》2011,257(12):5439-5442
Changes of thermal diffusivity inside femtosecond laser-structured volumes as small as few percent were reliably determined (with standard deviation less than 1%) with miniaturized sensors. An increase of thermal diffusivity of a crystalline high-density polyethylene (HDPE) inflation films by 10-20% from the measured (1.16 ± 0.01) × 10−7 m2 s−1 value in regions not structured by femtosecond laser pulses is considerably larger than that of non-crystalline polymers, 0-3%. The origin of the change of thermal diffusivity are interplay between the laser induced disordering, voids’ formation, compaction, and changes in molecular orientation. It is shown that laser structuring can be used to modify thermal and optical properties. The birefringence and infrared spectroscopy with thermal imaging of CH2 vibrations are confirming inter-relation between structural, optical, and thermal properties of the laser-structured crystalline HDPE inflation films. Birefringence modulation as high as Δn ∼ ± 1 × 10−3 is achieved with grating structures. 相似文献
84.
Hisatoshi Kura Kan Fujihara Akira Kimura Teruhisa Ohno Michio Matsumura Yoshinori Hirata Tadashi Okada 《Journal of Polymer Science.Polymer Physics》2001,39(23):2937-2946
The anthracene‐sensitized photodecomposition of diphenyliodonium hexafluorophosphate was studied in an epoxy matrix. From steady‐state photolysis, the generation of protons, which are considered to be the actual initiators of the polymerization of epoxides, was confirmed. In addition, 9‐phenylanthracene was detected as a main product from anthracene. From time‐resolved laser‐flash photolysis, a broad absorption band with a peak at about 500 nm was observed that was thought to be due to the precursor of 9‐phenylanthracene. On the basis of these results, we propose electron transfer from anthracene in the excited singlet state to the diphenyliodonium cation as the initial step of photoacid generation. This process is followed by fast chemical reactions, which generate 9‐phenylanthracene and protons, and back electron transfer from the diphenyliodine radical to the anthracene cation radical. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2937–2946, 2001 相似文献
85.
86.
Masayuki Hirata Kaori Kobayashi Yoshiharu Kimura 《Journal of polymer science. Part A, Polymer chemistry》2010,48(4):794-801
Di‐stereoblock polylactides (di‐sb‐PLA: PLLA‐b‐PDLA) having high molecular weight (Mn > 100 kDa) were successfully synthesized by two‐step ring‐opening polymerization (ROP) of L ‐ and D ‐lactides using tin(2‐ethylhexanoate) as a catalyst. By optimizing the polymerization conditions, the block sequences were well regulated at non‐equivalent feed ratios of PLLA and PDLA. This synthetic method consisted of three stages: (1) polymerization of either L ‐ or D ‐lactide to obtain a PLLA or PDLA prepolymer with a molecular weight less than 50 kDa, (2) purification of the obtained prepolymer to remove residual lactide, and (3) polymerization of the enantiomeric lactide in the presence of the purified prepolymer. Their 13C and 31P NMR spectra of the resultant di‐sb‐PLAs strongly supported their di‐stereo block structure. These di‐sb‐PLAs, having weight‐average molecular weights higher than 150 kDa, were fabricated into polymer films by solution casting and showed exclusive stereocomplexation. The thermomechanical analysis of the films revealed that their heat deformation temperature was limited probably because of their low crystallinity owing to the non‐equivalent PLLA/PDLA ratio. The blend systems of the di‐sb‐PLAs having complementary stereo‐sequences (the one with a long PLLA block and the other with long PDLA block) were also prepared and characterized to enhance the sc crystallinity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 794–801, 2010 相似文献
87.
Mitsuhiro Hirata Yutaka Abe Bungo Ochiai Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2010,48(20):4385-4392
Various star‐shaped poly(phenoxy propylene sulfide)s (PPSs) bearing curable end groups were synthesized by the functionalization of the propagating ends of star‐shaped poly(PPS) with various electrophilies. The functionalization with chloromethyl styrene proceeded quantitatively, and afforded polymers with Mn almost agreed with theoretical value and narrow Mw/Mn. The photocuring conditions were optimized, and the addition of 10 wt % of poly(ethylene glycol) diacrylate was effective to attain sufficient crosslinking. The photocuring reaction of the end‐functionalized poly(PPS) films cast on silicon wafers was conducted by UV irradiation. The cured poly (PPS)s became insoluble in THF, supporting the sufficient crosslinking. Developing of a cured polymer yielded a negative photoresist pattern. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
88.
H. Hirata H. Komatsubara W. Blumund H. S. Rawdon R. Glockerund E. Kaupp F. Foerster G. L. Clark P. K. Frölich A. H. W. Aten L. M. Boerlage V. Kohlschütter A. Good F. Jakober D. J. Brown J. Heyrovsky F. S. Aumonier H. J. S. Sand J. E. Hackford H. S. Lukens A. Schleicher L. Toussaint A. Lassieur S. Wiechowski H. Rom A. Jilek J. Lukas Erich Müller R. Belasio E. Mellana P. Drossbach H. Ginsberg R. Geith 《Analytical and bioanalytical chemistry》1928,75(6):244-255
89.
4-(3,17Beta-dihydroxyestra-1,3,5(10)-trien-6alpha- and 6beta-yl)amino-7-nitro-2,1,3-benzoxadiazoles have been synthesized and characterized as fluorescent probes for use in a receptor assay and/or a homogeneous immunoassay for estradiol. The fluorescence intensities are strongly dependent upon the solvent polarity used. The intensities in water were reduced to less than 1% of those in ethyl acetate, and a blue shift was also observed in polar solvents. The quenched fluorescence in aqueous solution was recovered by adding bovine serum albumin or an anti-estradiol antibody. Adding intact estradiol inhibited the fluorescence recovered by the antibody. 相似文献
90.
We analyze the production of H dihyperson (J π=0+,S=?2) via the (K ?, K+) reaction by means of the non-relativistic quark model. First, the H mass and mass spectrum of single baryons are calculated. When the single baryon spectrum is well reproduced, the H dihyperson has the binding energies about 20 MeV or 60 MeV corresponding to the choice of the strength of the confinement potential. Using this model and parameters, cross sections for H production are estimated. A new effect, contributions from color-octetQ 3?Q 3 components of H dihyperson, is taken into account. The cross sections for H production are enhanced about ten times by these contributions. TheK +-neutron coincidence cross section for H production is found to be 99–115 nb/sr2 at theK + forward direction forM H=2212 MeV and theK ? beam momentum 1.8 GeV/c. 相似文献