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991.
Manabu Sugimoto Ichiro Yamasaki Nobuteru Mizoe Masaharu Anzai Shigeyoshi Sakaki 《Theoretical chemistry accounts》1999,102(1-6):377-384
Acetylene insertion into Pt(II)–H and Pt(II)SiH3 bonds of PtH(SiH3)(PH3) was investigated using ab initio molecular orbital and M?ller-Plesset perturbation theory methods. The insertion into PtH
was predicted to proceed with a smaller activation energy (E
a
=12.8 kcal/mol) than that into PtSiH3 (E
a
=20.9 kcal/mol). The reaction energy (ΔE) of the insertion into PtH is 10 kcal/mol smaller than that for the insertion into PtSiH3, which reflects differences in bond energies between CH and CSi and between PtH and PtSiH3. A comparison with ethylene insertion revealed that the acetylene insertion occurs more easily, and the latter reaction is
more exothermic. A simple vibronic coupling model combined with Toyozawa's interaction mode analysis was used to examine interesting
differences in E
a
and ΔE between insertions into PtH and PtSiH3, and between acetylene and ethylene insertions. This analysis suggests that the factors determining E
a
are the stiffness of the PtH and PtSiH3 bonds and the vibronic coupling strength of acetylene and ethylene.
Received: 13 August 1998 / Accepted: 2 September 1998 / Published online: 15 February 1999 相似文献
992.
Takashi Shimada Sinya Ogumo Kayo Sawada Youichi Enokida Ichiro Yamamoto 《Analytical sciences》2006,22(11):1387-1391
In order to study the decontamination nature of the reactive extraction of uranium in the presence of some metal chemicals using a single-phase mixture of HNO(3), H(2)O and tri-n-butylphosphate (TBP) in supercritical carbon dioxide (SC-CO(2)), we measured the decontamination factors (DFs) of Sr, Zr, Mo, Ru, Pd, Ce and Nd from their mixture with U. These elements were originally added to U(3)O(8) as SrO, ZrO(2), MoO(3), RuO(2), Pd, CeO(2) and Nd(2)O(3), and the extraction was performed at 18 MPa and 323 K with the single-phase mixture. The DFs for these elements were determined to be greater than 10(3) when the molecular ratio of U to TBP in the extracted complex was greater than 0.3. Dilution by SC-CO(2) effectively increased the DFs. 相似文献
993.
Ichiro Shimada 《Geometriae Dedicata》2006,120(1):141-177
We investigate singularities of a general plane section of the dual variety of a smooth projective variety, or more generally, the discriminant variety associated with a linear system of divisors on a smooth projective variety. We show that, in characteristic 3, singular points of E
6-type take the place of ordinary cusps in characteristic 0. 相似文献
994.
Masafumi Fujimoto 《Journal of statistical physics》1996,82(5-6):1519-1539
We investigate the six-vertex model on a square lattice rotated through an arbitrary angle with respect to the coordinate axes, a model recently introduced by Litvin and Priezzhev. Auxiliary vertices are used to define an inhomogeneous system which leads to a one-parameter family of commuting transfer matrices. A product of commuting transfer matrices can be interpreted as a transfer matrix acting on zigzag walls in the rotated system. Using an equation for commuting transfer matrices, we calculate their eigenvalues. Finite-size properties of the model are discussed from the viewpoint of the conformal field theory. 相似文献
995.
Feasibility of carboxymethylcellulose with phenol moieties as a material for mammalian cell-enclosing subsieve-size capsules 总被引:1,自引:0,他引:1
Shinji Sakai Sho Ito Yuko Ogushi Ichiro Hashimoto Koei Kawakami 《Cellulose (London, England)》2008,15(5):723-729
Mammalian cell-enclosing capsules have been investigated as devices for bioproduction, cell therapy and stem cell research.
In this study, carboxymethylcellulose (CMC) with phenol moieties (CMC-Ph), synthesized through the conjugation reaction of
CMC and tyramine, was investigated as a material for these types of devices. Subsieve-size capsules of less than 100 μm in
diameter were prepared by extruding aqueous CMC-Ph solution into co-flowing liquid paraffin containing H2O2. The capsule diameter was controlled between 60–220 μm by changing the flow rate of liquid paraffin. There was no harmful
effect specific for CMC-Ph on mammalian cells enclosed in capsules. Feline kidney cells enclosed in subsieve-size CMC-Ph capsules
exhibited 87.0 ± 4.5% viability. In addition, the enclosed cells continued to grow over 13 days of study. These results demonstrated
the feasibility of CMC-Ph as a material for subsieve-size cell-enclosing capsules prepared via the droplet breakup technique
in a co-flowing water-immiscible fluid. 相似文献
996.
997.
Polarization of double bonds in homoconjugated systems has been studied by the use of MO theory and the results obtained have been compared with experimental findings. It has been suggested that the substituent effects are reduced by a structurally determined factor ~ when they are transmitted through homoconjugation and that the rate of attenuation of the effects would also depend on substituents, being slower in the case of strongly electron-releasing or withdrawing groups and faster in the case of weakly electron-releasing or withdrawing groups. An aspect of polarization in multicyclic conjugated molecules induced by the attacking electrophiles has been discussed in some detail, yielding a fair agreement between the theoretical conclusion and the experimental results accumulated so far. 相似文献
998.
999.
Absolute Measurement of Second-Order Nonlinear Optical Coefficient of LiNbO3 by Parametric Processes
We have redetermined the absolute values of the nonlinear optical coefficient, d31, of LiNbO3 by parametric fluorescence and, for the first time, by difference frequency generation measurements to resolve the considerable discrepancy that existed between the values determined by second-harmonic generation (SHG) and parametric fluorescence. We obtain d31 = 4.8±0.5 and 4.3±0.5 pm/V at the pump wavelengths of 488 and 532 nm, respectively, in reasonable agreement with the SHG data. It appears that the previous parametric fluorescence value, d31=5.8 pm/V, was overestimated.Author to whom correspondence should be addressed. 相似文献
1000.
It is proved that the rank of the non-trivial polynomial conserved density of the fifth-order KdV equation is 3p–2 or 3p (p=1, 2, ...). 相似文献