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991.
992.
Fumio Sanda Toshikazu Takata Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》1994,32(13):2517-2522
Synthesis and radical crosslinking reaction of poly (vinylcyclopropanone acetal)s ( 4 ), volume change on the crosslinking, and thermal analysis of 4 and the crosslinked polymers were carried out. 4 was prepared by the reaction of 1,1-dichloro-2-vinylcyclopropane with sodium dialkoxides. Radical crosslinking of 4a was carried out in the presence of AIBN, BPO, or DTBP at 60, 80, or 120°C, respectively. 4a afforded no dichloromethane-insoluble part in the crosslinking in chlorobenzene but afforded in 37% yield in bulk at 120°C. On the other hand, 4b afforded dichloromethane-insoluble part in 33% yield in the crosslinking in chlorobenzene at 120°C. Volume shrinkage of 4a and 4b on crosslinking at 120°C was 4.11 and 3.55%, respectively. Glass transition temperatures of the crosslinked polymers obtained from 4a and 4b were 28 and 163°C, respectively, which were 32 ~ 49°C higher than those before crosslinking. © 1994 John Wiley & Sons, Inc. 相似文献
993.
Kiyoshi Kikukawa Takatoshi Totoki Fumio Wada Tsutomu Matsuda 《Journal of organometallic chemistry》1984,270(3):283-287
Arenediazonium tetrafluoroborates (ArN2BF4 where Ar = X-C6H4; X = H, 2-Me, 3-Me, 4-Me, 4-MeO, 4-MeCO, 4-EtOCO, 2-Ph, 2-Cl, 3-Cl, 4-Cl, 4-Br, 4-I, 3-NO2 and 4-NO2) were easily converted to aromatic aldehydes (ArCHO) in good yields through the palladium-catalyzed reaction with CO and Et3SiH or polymethylhydrosiloxane (PMHS) at room temperature. 相似文献
994.
995.
Atsuyoshi Ohno Jun Kunitomo Tetsuji Kawamoto Masaki Tomishima Kiyoshi Bessho Fumio Yoneda 《Tetrahedron letters》1994,35(52):9729-9732
A chiral 5-deazaflavin derivative with 2-hydroxymethylphenyl group at N(3) position of the pyrimidine ring has been synthesized. Oxidized form of the 5-deazaflavin derivative is reduced stereo-specifically: the hydroxymethyl group exerts steric inhibition in the absence of Mg2+, whereas it facilitates the approach of a reducing agent in the presence of Mg2+. 相似文献
996.
Fumio Sakaguchi Leo Mandelkern John Maxfield 《Journal of Polymer Science.Polymer Physics》1976,14(12):2137-2152
After annealing at low temperature, linear polyethylene displays an unusual feature in its specific heat curve. On heating, a maximum is observed just above the annealing temperature. The magnitude of this excess specific heat is dependent on the initial level of crystallinity and the temperature and time of annealing. The maximum does not reappear on subsequent cooling followed by rapid heating and represents the formation and disappearance of an unstable structure. These results can be interpreted as a crystallization-melting phenomenon and are consistent with the wide-angle x-ray diffraction patterns. The optimum effects are observed in the β-region (?50°C to 0°C) and could possibly lead to complications in interpreting other phenomena in this temperature range. 相似文献
997.
998.
Takashi Harayama Reiko Yanada Tooru Taga Katsunosuke Machida Fumio Yoneda 《Journal of heterocyclic chemistry》1986,23(1):283-285
Each reaction of dl-1,3-dimethylthymine epoxide ( 1 ) with L-amino acid ethyl esters (Pro-OEt, Met-OEt, Phe-OEt, and Trp-OEt) afforded the respective four optically active diastereomers 4–7 , stereo structures of which were definitely elucidated as shown in Chart 1 by an X-ray analysis of 4A and chemical means. 相似文献
999.
Alavi-Harati A Alexopoulos T Arenton M Arisaka K Averitte S Barker AR Bellantoni L Bellavance A Belz J Ben-David R Bergman DR Blucher E Bock GJ Bown C Bright S Cheu E Childress S Coleman R Corcoran MD Corti G Cox B Crisler MB Erwin AR Ford R Glazov A Golossanov A Graham G Graham J Hagan K Halkiadakis E Hamm J Hanagaki K Hidaka S Hsiung YB Jejer V Jensen DA Kessler R Kobrak HG LaDue J Lath A Ledovskoy A McBride PL Mikelsons P Monnier E Nakaya T Nelson KS Nguyen H O'Dell V Pang M Pordes R 《Physical review letters》2001,86(15):3239-3243
We have studied the rare weak radiative hyperon decay Xi degrees -->Sigma degrees gamma in the KTeV experiment at Fermilab. We have identified 4045 signal events over a background of 804 events. The dominant Xi degrees -->Lambdapi degrees decay, which was used for normalization, is the only important background source. An analysis of the acceptance of both modes yields a branching ratio of B(Xi degrees -->Sigma degrees gamma)/B(Xi degrees -->Lambdapi degrees ) = (3.34+/-0.05+/-0.09)x10(-3). By analyzing the final state decay distributions, we have also determined that the Sigma degrees emission asymmetry parameter for this decay is alpha(XiSigma) = -0.63+/-0.09. 相似文献
1000.
Kazunori Kadota Atsuko Shimosaka Yoshiyuki Shirakawa Jusuke Hidaka 《Journal of nanoparticle research》2007,9(3):377-387
Ionic motions at solid-liquid interface in supersaturated NaCl solutions have been investigated by molecular dynamics (MD)
simulation for understanding crystal growth processes. The density profile in the vicinity of the interfaces between NaCl(100)
and the supersaturated NaCl solution was calculated. Diffusion coefficients of water molecules in the solution were estimated
as a function of distance from the crystal interface. It turned out that the structure and dynamics of the solution in the
interfaces was different from those of bulk solution owing to electric fields depending on the surface charge. Therefore,
the electric field was applied to the supersaturated solutions and dehydration phenomenon occurring in the process of the
crystal growth was discussed. As the electric field increased, it was observed that the Na+ keeping strongly hydration structure broke out by the electric force. In supersaturated concentration, the solution structure
is significantly different from that of dilution and has a complicated structure with hydration ions and clusters of NaCl.
If the electric fields were applied to the solutions, the breakout of hydration structure was not affected with increasing
the supersaturated ratio. This reason is that the cluster structures are destroyed by the electric force. The situation depends
on the electric field or crystal surface structure. 相似文献