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741.
S. Kawasaki S. Yoshikawa T. Imasaka N. Ishibashi 《Applied physics. B, Lasers and optics》1993,56(5):259-262
A laser beam at two different frequencies separated by 587 cm–1 is focused into pressurized hydrogen (rotational transition energy, 587 cm–1) to generate multi-color stimulated Raman emission. The polarization state and the pulse energy are measured for each generated emission line using linearly and circularly polarized pump beams. The effect of the polarization is discussed by using a parameter characterizing the polarizability of hydrogen and a conservation rule for the angular momentum in four-wave mixing. Many rotational lines are generated with linearly polarized pump beams through a four-wave mixing process. This is in striking contrast to the results obtained by using a single-color circularly polarized pump beam which generates only one rotational line through a conventional stimulated Raman process. 相似文献
742.
743.
The present paper studies globally defined Kropina metrics as solutions of the Zermelo’s navigation problem. Moreover, we characterize the Kropina metrics of constant flag curvature showing that up to local isometry, there are only two model spaces of them: the Euclidean space and the odd-dimensional spheres. 相似文献
744.
Král R. Zemenová P. Vaněček V. Bystřický A. Kohoutková M. Jarý V. Kodama S. Kurosawa S. Yokota Y. Yoshikawa A. Nikl M. 《Journal of Thermal Analysis and Calorimetry》2020,141(3):1101-1107
Journal of Thermal Analysis and Calorimetry - This paper reports on the preparation of undoped cesium hafnium chloride (Cs2HfCl6) and study of its thermal properties. The Cs2HfCl6 is considered,... 相似文献
745.
Mayu Inamori Takeshi Yoshikawa Yasuhiro Ikabata Yoshifumi Nishimura Hiromi Nakai 《Journal of computational chemistry》2020,41(16):1538-1548
A spin-flip time-dependent density functional tight-binding (SF-TDDFTB) method is developed that describes target states as spin-flipping excitation from a high-spin reference state obtained by the spin-restricted open shell treatment. Furthermore, the SF-TDDFTB formulation is extended to long-range correction (LC), denoted as SF-TDLCDFTB. The LC technique corrects the overdelocalization of electron density in systems such as charge-transfer systems, which is typically found in conventional DFTB calculations as well as density functional theory calculations using pure functionals. The numerical assessment of the SF-TDDFTB method shows smooth potential curves for the bond dissociation of hydrogen fluoride and the double-bond rotation of ethylene and the double-cone shape of H3 as the simplest degenerate systems. In addition, numerical assessments of SF-TDDFTB and SF-TDLCDFTB for 39 S0/S1 minimum energy conical intersection (MECI) structures are performed. The SF-TDDFTB and SF-TDLCDFTB methods drastically reduce the computational cost with accuracy for MECI structures compared with SF-TDDFT. 相似文献
746.
K. Yoshikawa 《Macromolecular Symposia》1996,106(1):367-378
Transition of a single duplex DNA between elongated coil and condensed globule has been studied by the technique of single molecular observation with fluorescence microscopy. It has become clear that individual DNA chains undergo first-order phase transition. We have observed the time-dependent change of the DNA structure accompanied with the phase transition from coil to globule. The speed of the compaction was found to be almost constant along the DNA chain. It is indicated that the coil-globule transition exhibits the phenomenon of “nucleation and growth”. The process of the decollapse of a single DNA has also been observed, the time dependence of the long axis length being described as l ∼ t1.8. 相似文献
747.
Recently, it has been found that individual giant DNA molecules exhibit a discrete transition, or first order phase‐transition, between the compact folded state and the elongated coiled state, i.e., the folding transition. In order to clarify the thermodynamics in the folding transition of single DNA molecules, we have studied the temperature effect on the bimodal distribution of conformation for the ensemble of T4DNA chains (166 kbps) in both poly(ethylene glycol) (PEG) and spermidine (SPD), using single‐chain observation with fluorescence microscopy. From the van't Hoff relationship, the entropy change in the transition from the compact state to the unfolded state is deduced as, ΔS = +11, +38 k/molecule in the aqueous solution of PEG with sodium chloride and potassium chloride, respectively, where k is Boltzmann's constant, whereas, ΔS with SPD is estimated to be −32 k/molecule. The values of ΔS with the transition are discussed in term of the translational entropy of counterions together with the hydration effect. 相似文献
748.
749.
750.
Elena Yu. Kramarenko Alexei R. Khokhlov Kenichi Yoshikawa 《Macromolecular theory and simulations》2000,9(5):249-256
In this paper we consider the influence of counterion distribution on the behavior of polyelectrolyte systems. We propose the unified model to describe and to compare the swelling and collapse properties of single polyelectrolyte chains in dilute solutions, microgel particles of various molecular masses, and (as a limiting case) macroscopic gels. A novel feature of the new approach is that we distinguish three possible states of counterions: free counterions inside and outside the polymer macromolecule and a bound state of counterions forming ion pairs with corresponding ions of polymer chains. The latter possibility becomes progressively important when macromolecules or gels shrink. In this case the formation of a supercollapsed state is possible, when all couterions are trapped and form ion pairs. On the other hand, the fact that counterions can float in the outer solution affects essentially the conformation of polyelectrolyte chains in dilute solutions of good quality where practically all counter ions can escape the space inside polymer coils and the repulsion between uncompensated charges plays an important role in the chain behavior. 相似文献