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981.
Hadizadeh MR Yamashita MT Tomio L Delfino A Frederico T 《Physical review letters》2011,107(13):135304
We evidence the existence of a universal correlation between the binding energies of successive four-boson bound states (tetramers), for large two-body scattering lengths (a), related to an additional scale not constrained by three-body Efimov physics. Relevant to ultracold atom experiments, the atom-trimer relaxation peaks for |a|→∞ when the ratio between the tetramer and trimer energies is ?4.6 and a new tetramer is formed. The new scale is also revealed for a < 0 by the prediction of a correlation between the positions of two successive peaks in the four-atom recombination process. 相似文献
982.
Kazuhiro Yamamoto Yoshinori Ogata Hiroshi Yamashita 《Proceedings of the Combustion Institute》2011,33(2):2441-2448
We have investigated the downward flame spread over a thin solid fuel. Hydrogen, methane, or propane, included in the gaseous product of pyrolysis reaction, is added in the ambient air. The fuel concentration is kept below the lean flammability limit to observe the partially premixing effect. Both experimental and numerical studies have been conducted. Results show that, in partially premixed atmospheres, both blue flame and luminous flame regions are enlarged, and the flame spread rate is increased. Based on the flame index, a so-called triple flame is observed. The heat release rate ahead of the original diffusion flame is increased by adding the fuel, and its profile is moved upstream. Here, we focus on the heat input by adding the fuel in the opposed air, which could be a direct factor to intensify the combustion reaction. The dependence of the flame spread rate on the heat input is almost the same for methane and propane/air mixtures, but larger effect is observed for hydrogen/air mixture. Since the deficient reactant in lean mixture is fuel, the larger effect of hydrogen could be explained based on the Lewis number consideration. That is, the combustion is surely intensified for all cases, but this effect is larger for lean hydrogen/air mixture (Le < 1), because more fuel diffuses toward the lean premixed flame ahead of the original diffusion flame. Resultantly, the pyrolysis reaction is promoted to support the higher flame spread rate. 相似文献
983.
984.
Hiroyuki Moriyama Nobuo Yamashita Masao Fukushima 《Computational Optimization and Applications》2003,26(2):107-141
In this paper, we consider the Extended Kalman Filter (EKF) for solving nonlinear least squares problems. EKF is an incremental iterative method based on Gauss-Newton method that has nice convergence properties. Although EKF has the global convergence property under some conditions, the convergence rate is only sublinear under the same conditions. One of the reasons why EKF shows slow convergence is the lack of explicit stepsize. In the paper, we propose a stepsize rule for EKF and establish global convergence of the algorithm under the boundedness of the generated sequence and appropriate assumptions on the objective function. A notable feature of the stepsize rule is that the stepsize is kept greater than or equal to 1 at each iteration, and increases at a linear rate of k under an additional condition. Therefore, we can expect that the proposed method converges faster than the original EKF. We report some numerical results, which demonstrate that the proposed method is promising. 相似文献
985.
Y. Toda T. Nakaoka R. Morita M. Yamashita T. Inoue Y. Arakawa 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):180
We carried out optical selective excitation of individual self-assembled quantum dots by using phase-modulated pulses. Based on scattered photoluminescence excitation resonances in individual QDs, the excitation pulses modulated in the spectral region allows for addressing individual ground states emission. The photoluminescence spectra including several QDs showed intensity changes according to both the modulation energies and phases. The results also suggested the individual control of selective QDs even in collective excitation. 相似文献
986.
Prof. Keiichi Katoh Dr. Nobuhiro Yasuda Dr. Marko Damjanović Prof. Wolfgang Wernsdorfer Prof. Brian K. Breedlove Prof. Masahiro Yamashita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(21):4805-4815
A supramolecular complex ( 1⋅ C60) was prepared by assembling (C60-Ih)[5,6]fullerene (C60) with the dinuclear Tb3+ triple-decker complex [(TPP)Tb(Pc)Tb(TPP)] ( 1 : Tb3+=trivalent terbium ion, Pc2−=phthalocyaninato, TPP2−=tetraphenylporphyrinato) with quasi-D4h symmetry to investigate the relationship between the coordination symmetry and single-molecule magnet (SMM) properties. Tb3+-Pc triple-decker complexes (Tb2Pc3) have an important advantage over Tb3+-Pc double-decker complexes (TbPc2) since the magnetic relaxation processes correspond to the Zeeman splitting when there are two 4f spin systems. The two Tb3+ sites of 1 are equivalent, and the twist angle (φ) was determined to be 3.62°. On the other hand, the two Tb3+ sites of 1⋅ C60 are not equivalent. The φ values for sites Tb1 and Tb2 were determined to be 3.67° and 33.8°, respectively, due to a change in the coordination symmetry of 1 upon association with C60. At 1.8 K, 1 and 1⋅ C60 undergo different magnetic relaxations, and the changes in the ground state affect the spin dynamics. Although 1 and 1⋅ C60 relax via QTM in a zero applied magnetic field (H), H dependencies of the magnetic relaxation times (τ) for H>1500 Oe are similar. On the other hand, for H<1500 Oe, the τ values have different behaviors since the off-diagonal terms ( ) affect the magnetic relaxation mechanism. From temperature (T) and H dependences of τ, spin-phonon interactions along with direct and Raman mechanisms explain the spin dynamics. We believe that a supramolecular method can be used to control the magnetic anisotropy along the C4 rotation axis and the spin dynamic properties in dinuclear Ln3+-Pc multiple-decker complexes. 相似文献
987.
988.
Bio-template methods for the synthesis of inorganic nano-particles are now attracting researchers’ interest in the bionanotechnology
field. Using the protein cage, apoferritin, researchers have synthesized various kinds of nano-particles such as metal oxide
nano-particles (Co, Ni, Cr nano-particles) and semiconductor nano-particles (CdSe, ZnSe) with a diameter of 7 nm. The synthesized
nano-particles have high quality and a small diameter distribution. The mechanism of biomineralization in apoferritin has
been studied and some knowledge has been accumulated. Biologically synthesized nanoparticles are now applicable to nanoelectronic
devices and it is possible to produce floating gate memory with a monolayer of nanodots fabricated using apoferritins. 相似文献
989.
Hidemitsu Uno Yuko Yamashita Hikaru Watanabe Tetsuo Okujima Noboru Ono 《Tetrahedron letters》2005,46(12):1981-1983
6,13-Dihydro-6,13-ethanopentacene-15,16-dione gave pentacene efficiently both in solid and in solution by irradiation of light. 相似文献
990.
Nickel complex catalysts, Ni(cod)2-2PPh3 and Ni(cod)2-dppb systems in particular, catalyze the addition reactions of phenyl allyl selenide to terminal alkynes to regioselectively afford 2-phenylseleno-1-allyl-1-alkenes in good to excellent yields. A mechanism that involves a η3-allyl-nickel complex is proposed on the basis of isolation, crystal structure determination and reactivity study of the complex. 相似文献