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991.
Daisuke Yamano Masahiro Kawasaki Agnes Perrin 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(1):45-10728
We present the high resolution absorption measurements of gaseous HONO at room temperature using continuous-wave cavity ring-down spectroscopy in the near-infrared region between 6017 and 6067 cm−1 at a resolution of 1 pm (0.037 cm−1). For the trans-HONO isomer an extensive analysis of the ν1+2ν3 combination band 6045.8089 cm-1 was performed starting from the results of a previous study for the 11 and 31 vibrational states [Guilmot J-M, Godefroid M, Herman M. Rovibrational parameters for trans-nitrous acid. J Mol Spectrosc 1993;160:387-400]. The present combination band is perturbed because of the existence of several dark states of HONO which could not be identified unambiguously. The rotational constants achieved for the 1132 state deviate slightly from the values which are predicted from the rotational constants achieved in the previous studies for the 11 and 31 vibrational states of trans-HONO. 相似文献
992.
Satoshi Fujita 《Mathematics in Computer Science》2010,3(1):31-38
This paper introduces a new definition of embedding a local structure to a given network, called loose cover of graphs. We derive several basic properties on the notion of loose cover, which includes transitivity, maximality, and
the computational complexity of finding a loose cover by paths and cycles. In particular, we show that the decision problem
is in P if the given local structure is a path with three or less vertices, while it is NP-complete for paths consisting of
six or more vertices. 相似文献
993.
W H Chen S Hayashi T Tahara Y Nogami T Koga M Yamaguchi K Fujita 《Chemical & pharmaceutical bulletin》1999,47(4):588-589
Secondary imidazole-appended beta-cyclodextrin 5 with a nondistorted cavity synthesized from a novel intermediate 3-amino-3-deoxy-beta-cyclodextrin exhibits much greater catalytic activity in the ester hydrolysis than its isomer 6 with a distorted cavity, indicating that the catalytic activities of secondary functional cyclodextrins are dependent on cavity structures. 相似文献
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Satoshi Yamasaki Daisuke Nishiguchi Ken Kojio Mutsuhisa Furukawa 《Journal of Polymer Science.Polymer Physics》2007,45(7):800-814
The effects of the dynamic polymerization method and temperature on the molecular aggregation structure and the mechanical and melting properties of thermoplastic polyurethanes (TPUs) were successfully clarified. TPUs were prepared from poly (ethylene adipate) glycol (Mn = 2074), 4,4′‐diphenylmethane diisocyanate and 1,4‐butanediol by the one‐shot (OS) and the prepolymer (PP) methods in bulk at dynamic polymerization temperatures ranging from 140 to 230 °C. Glass‐transition temperatures (Tgs) of the soft segment and melting points (Tms) of the hard segment domains of OS‐TPUs increased and decreased, respectively, with increasing polymerization temperatures, but those of PP‐TPUs were almost independent of the polymerization temperature. Tgs of the soft segment and Tms of the hard segment domains of these TPUs polymerized above 190 °C were almost the same regardless of the polymerization method. Solid‐state nuclear magnetic resonance spectroscopy (NMR) analyses of OS‐ and PP‐TPUs showed that the relative proton content of fast decay components, which corresponds to the hard segment domains, in these TPUs decreased with increasing polymerization temperatures. These results clearly show that the degree of microphase separation becomes weaker with increasing polymerization temperatures. The temperature dependence of dynamic storage modulus and loss tangent of OS‐TPUs coincided with those of PP‐TPUs at polymerization temperature above 190 °C. The apparent shear viscosity for OS‐ and PP‐TPUs polymerized above 190 °C approached a Newtonian behavior at low shear rates regardless of the polymerization method. These results indicate that TPUs polymerized at higher temperatures form almost the same molecular aggregation structures irrespective of the dynamic polymerization method. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 800–814, 2007 相似文献