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991.
In this note we present a unified approach, based on pde methods, for the study of averaging principles for (small) stochastic perturbations of Hamiltonian flows in two space dimensions. Such problems were introduced by Freidlin and Wentzell and have been the subject of extensive study in the last few years using probabilistic arguments. When the Hamiltonian flow has critical points, it exhibits complicated behavior near the critical points under a small stochastic perturbation. Asymptotically the slow (averaged) motion takes place on a graph. The issues are to identify both the equations on the sides and the boundary conditions at the vertices of the graph. Our approach is very general and applies also to degenerate anisotropic elliptic operators which could not be considered using the previous methodology. 相似文献
992.
Esterifying chains of chlorophyllous pigments play important roles in the formation of photosynthetic supramolecules, but their effects have not thoroughly been unraveled yet. Substitution of the esterifying chains in these pigments will be one possible strategy to elucidate this enigma. Recently, unnatural bacteriochlorophylls (BChls) c possessing a hydroxy group at the terminus of the esterifying chains were successfully biosynthesised in the green sulfur bacterium Chlorobaculum (Cba.) tepidum grown by supplementation of α,ω-diols. In this paper, in vitro assembling behaviours of unnatural BChls c isolated from Cba. tepidum grown with 1,8-octanediol, 1,12-dodecanediol and 1,16-hexadecanediol were characterised in aqueous Triton X-100 micelles to investigate the effects of the terminal hydroxy group in the esterifying chains of BChls c on self-aggregates such as chlorosomes, major antenna complexes in green photosynthetic bacteria. The bacteriochlorophyll (BChl) c derivatives monoesterified with α,ω-diols formed chlorosomal self-aggregates, but their formations were much slower than those of natural BChl c. The Qy absorption bands of the residual monomers of these BChl c derivatives were larger than those of natural BChl c. These suggest that the esterifying α,ω-diols in these unnatural BChls c somewhat interfered with formation of chlorosome-like aggregates compared with the natural esterifying farnesol. 相似文献
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Dr. Hitoshi Kasai Dr. Tatsuya Murakami Yoshikazu Ikuta Yoshitaka Koseki Dr. Koichi Baba Prof. Hidetoshi Oikawa Prof. Hachiro Nakanishi Dr. Masahiro Okada Mitsuru Shoji Prof. Minoru Ueda Prof. Hiroshi Imahori Prof. Mitsuru Hashida 《Angewandte Chemie (International ed. in English)》2012,51(41):10315-10318
996.
Hitoshi Murayama Vikram Rentala Jing Shu Tsutomu T. Yanagida 《Physics letters. [Part B]》2011,705(3):208-211
Recent studies of precision electroweak observables have led to the conclusion that a fourth generation is highly constrained. However, we point out that a long-lived fourth generation can reopen a large portion of the parameter space. In addition, it preserves baryon and lepton asymmetries against sphaleron erasure even if B−L=0. It opens up the possibility of exact B−L symmetry and hence Dirac neutrinos. The fourth generation can be observed at the LHC with unique signatures of long-lived particles in the near future. 相似文献
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Hitoshi Ohta Minoru Kojima Keigo Nagasaka Tadahiro Ishii 《Molecular Crystals and Liquid Crystals》2013,570(2):291-305
Lattice dynamical calculations of the lattice modes for both trans and cis polyacetylene were performed. Using rigid body approximation for the chain we obtained all 8 lattice frequencies and modes of motion for both trans and cis polyacetylene. The frequencies concerned with Raman active lattice modes are presented for the first time. We also performed far infrared transmission measurements of undoped trans and cis polyacetylene and confirmed the results obtained by Bechtold et al. Comparison of the lattice frequencies obtained by lattice dynamical calculations with the results obtained by far infrared measurement and inelastic neutron scattering is discussed. 相似文献