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61.
62.
Toshifumi Satoh Tomoko Imai Norihiko Sugie Ryuji Nonokawa Kazuaki Yokota Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2002,40(8):965-970
The bulk cyclopolymerization of diepisulfide, 1,2:5,6‐diepithio‐3,4‐di‐O‐methyl‐1,2:5,6‐tetradeoxy‐D ‐mannitol ( 1 ), was studied using R4N+Br? (R = ? CH3, C2H5, C3H7, C4H9, and C7H15) and (C4H9)4N+X? (X = Cl, I, NO3, and ClO4) as the initiators. All the bulk polymerizations of 1 using quaternary tetraalkylammonium salts at 90 °C proceeded without gelation even at high conversion to produce gel‐free polymers consisting of 2,5‐anhydro‐1,5‐dithio‐D ‐glucitol (I) as the major cyclic repeating unit along with 1,5‐anhydro‐2,5‐dithio‐D ‐mannitol (II) and the desulfurized acyclic unit (III) as the minor units. The polymerization rate and molar fraction of the I unit increased with the increasing alkyl chain length of the tetraalkylammonium cation and the increasing nucleophilicity of the counteranion. Tetrabutylammonium chloride exhibited the highest catalytic activity and the highest stereoselectivity, that is, the thiosugar polymer with I:II:III = 81:15:4 and a number‐average molecular weight of 31.9 × 103 was obtained in 85% yield for a polymerization time of 0.5 h. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 965–970, 2002 相似文献
63.
The conformational potential energy surfaces for mono- and difluoromethyl formate have been determined by using a modified G2(MP2) level of calculations. The structures and vibrational frequencies for the conformers of mono- and difluoromethyl formate have been reported. The hydrogen abstraction reaction channels between these two formates and OH radicals have been studied at the same level of theory. Using the standard transition state theory and taking into account the effect of tunneling across the reaction barrier, we have estimated the rate constant for hydrogen abstraction by OH radical. The effect of successive fluorine substitution for methyl hydrogen on the conformational stability and on the hydrogen abstraction rate has been analyzed. 相似文献
64.
Kazuaki Tokuhashi Liang Chen Shuzo Kutsuna Tadafumi Uchimaru Masaaki Sugie Akira Sekiya 《Journal of fluorine chemistry》2004,125(11):1801-1807
The rate constants for the reactions of OH radicals with CF3OCHFCF3, and CF3CHFCF3 have been measured over the temperature range 250-430 K. Kinetic measurements have been carried out using the flash photolysis, and laser photolysis methods combined, respectively, with the laser induced fluorescence technique. The influence of impurities in the samples has been investigated by using gas chromatography. No sizable effect of impurities was found on the measured rate constants of these fluorinated compounds, if the purified samples were used in the measurements. The following Arrhenius expressions were determined: k(CF3OCHFCF3) = (4.39 ± 1.38) × 10−13 exp[−(1780 ± 100)/T] cm3 molecule−1 s−1, and k(CF3CHFCF3) = (6.19 ± 2.07) × 10−13 exp[−(1830 ± 100)/T] cm3 molecule−1 s−1. 相似文献
65.
Sugie A Somete T Kanie K Muramatsu A Mori A 《Chemical communications (Cambridge, England)》2008,(33):3882-3884
The reaction of HAuCl(4).4H(2)O and n-C(12)H(25)SH with 1 equiv. of Et(3)SiH in an organic solvent affords spherical gold nanoparticles (AuNPs) with narrow dispersity. 相似文献
66.
The present paper is concerned with the global dynamics of a discrete hematopoiesis model. This model has several unimodal production functions, and periodic coefficients and periodic time delays whose periods are the same $$\omega \in {\mathbb {N}}$$. Since these production functions are unimodal, they have no monotonicity. The obtained result guarantees that this model has only one positive $$\omega $$-periodic solution and its periodic solution is globally asymptotically stable. To prove that the unique positive $$\omega $$-periodic solution is globally asymptotically stable, the difference between that the periodic solution and an arbitrary other is analyzed in detail. It is necessary to evaluate the upper and lower limit values of all the positive solutions to carry out the detailed analysis. Because the production functions have no monotonicity, it is not easy to evaluate the upper and lower limit values of the solutions. Two suitable examples are included to illustrate the main result. Numerical simulation is presented for one of them. The other example is based on the upper and lower limit values of red blood cells for healthy humans known from clinical laboratory tests, and clinical data obtained from clinical studies. 相似文献
67.
J. Sugie 《Acta Mathematica Hungarica》2008,118(4):369-394
This paper deals with the second-order half-linear differential equation
Here ϕ
p
(z):= |z|
p−2
z is the so-called one-dimensional p-Laplacian operator. Our main purpose is to establish new criteria for all nontrivial solutions to be oscillatory and for
those to be nonoscillatory. In our theorems, the parametric curve given by (a(t), b(t)) plays a critical role in judging whether all solutions are oscillatory or nonoscillatory. This paper takes a di-erent approach
from most of the previous research. Our results are new even in the linear case (p = 2). The method used here is mainly phase plane analysis for a system equivalent to the half-linear differential equation.
Some suitable examples are included to illustrate the main results. Global phase portraits are also attached.
Supported in part by Grant-in-Aid for Scientific Research 19540182. 相似文献
68.
Jitsuro Sugie 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(18):7151-7167
A necessary and sufficient condition is established for the equilibrium of the oscillator of half-linear type with a damping term, (?p(x′))′+h(t)?p(x′)+?p(x)=0 to be globally asymptotically stable. The obtained criterion is given by the form of a certain growth condition of the damping coefficient h(t) and it can be applied to not only the cases of large damping and small damping but also the case of fluctuating damping. The presented result is new even in the linear cases (p=2). It is also discussed whether a solution of the half-linear differential equation (r(t)?p(x′))′+c(t)?p(x)=0 that converges to a non-zero value exists or not. Some suitable examples are included to illustrate the results in the present paper. 相似文献
69.
In this paper, we give some sufficient conditions which guarantee that the zero solution of the differential equation with two delayed terms x(t) = a(t)x(t-p(t)) - b(t)x(t-r(t))is uniformly stable 相似文献
70.
Kakei T Sumiyoshi H Higashi-Fujime S 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2012,88(5):201-211
Chara myosin is plant myosin responsible for cytoplasmic streaming and moves actin filaments at 60 µm/s, which is the fastest of all myosins examined. The neck of the myosin molecule has usually mechanical and regulatory roles. The neck of Chara myosin is supposed to bind six light chains, but, at present, we have no knowledge about them. We found Ca++-calmodulin activated Chara myosin motility and its actin-activated ATPase, and actually bound with the Chara myosin heavy chain, indicating calmodulin might be one of candidates for Chara myosin light chains. Antibody against essential light chain from Physarum myosin, and antibodies against Chara calmodulin and chicken myosin light chain from lens membranes reacted with 20 kDa and 18 kDa polypeptides of Chara myosin preparation, respectively. Correspondingly, column purified Chara myosin had light chains of 20 kDa, and 18 kDa with the molar ratio of 0.7 and 2.5 to the heavy chain, respectively. 相似文献