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71.
72.
M. Tohyama 《Zeitschrift für Physik A Hadrons and Nuclei》1990,335(4):413-416
Landau's expression for the spreading widths of giant resonances is derived, based on the small-amplitude limit of the time-dependent density-matrix theory. It is pointed out that a consistent treatment of the groundstate correlations is essential to obtain the expression. 相似文献
73.
Nishiwaki N Ogihara T Takami T Tamura M Ariga M 《The Journal of organic chemistry》2004,69(24):8382-8386
beta-Nitroenamines having a formyl group at the beta-position behave as the synthetic equivalent of unstable nitromalonaldehyde, which is a useful synthon for syntheses of versatile nitro compounds. High solubility of the nitroenamines into general organic solvents enables us to conduct reactions in the organic media accompanied by easy experimental manipulations and considerable safety. When nitroenamines are treated with 1,2-bifunctional nucleophiles such as hydrazines, hydroxylamine and glycine ester, nitrated pyrazoles, isoxazole and pyrrole-2-carboxylate were readily prepared. This methodology was also applicable to guanidines and 1,2-diamines, leading to pyrimidines and 1,4-diazepines, respectively. 相似文献
74.
Takami Seiichi Suzuki Ken Kubo Momoji Miyamoto Akira 《Journal of nanoparticle research》2001,3(2-3):213-218
The fate of clusters emitted onto a substrate falls into several categories including repulsion, soft landing, migration, and explosion, depending on the interaction between the cluster and the substrate. This dynamic behavior of the clusters controls thin-film formation processes from clusters such as cluster ion beam deposition and chemical vapor deposition. Here we describe the collision processes of both Al and Au clusters with a kinetic energy of 0.56 eV/atom onto an amorphous SiO2 substrate studied by molecular dynamics simulation, focusing on the dissipation of translational kinetic energy during the collision process. The simulation elucidated that the activation of thermal vibrational energy of the substrate promoted the sticking of the colliding clusters on the substrate. This result suggests that the dissipation of the translational kinetic energy of the colliding cluster is one of the factors that determine the structure formed on a substrate from vapor phase. 相似文献
75.
This paper reports on progress in the study of the water entry phenomenon. First, an experiment conducted measuring the velocity
of the projectile after water entry. An empirical formula was obtained describing the change of the velocity of an underwater
projectile with water depth. From the formula, the velocity decay coefficient β=0.5ρw
A
o
C
d/m, was determined, where ρw is the water density, A
o is the projection area of the projectile, C
d is the drag coefficient and m is the mass of the projectile. A theoretical model was then presented to describe the motion of the projectile during entry.
Based on the obtained value of β, when the projectile was treated equivalently as a sphere, the theoretical water depth for
deep closure of the cavity was predicted.
Received: 10 February 2000/Accepted: 20 July 2000 相似文献
76.
An experimental study was conducted to investigate the water entry phenomenon. A facility was designed to carry out the tests
with the entry velocities of around 352 m/s. Visualization, pressure measurement, velocity measurement and underwater impact
test were performed to investigate the hydroballistic behavior of the underwater moving body, the underwater flow field, the
supercavitation, etc.. This study shows that the motion of a high-speed underwater body is strongly three-dimensional and
chaotic. Furthermore, it is found that the distribution of the trajectory deflection of the underwater projectile depends
on the depth of water. It is also found by measuring the deformation on a witness plate submerged in water, that the impact
energy of an underwater projectile is reduced as it penetrates deeper into water.
The project supported by Japan Society for the Promotion of Science under a Grant-in-Aid for Scientific Research (C) (Grant
No. 12650162) 相似文献
77.
Bin Wen Seiichi Takami Yoshiyuki Kawazoe Tadafumi Adschiri 《Journal of Physics and Chemistry of Solids》2012,73(11):1264-1267
The mechanical stabilities of K4 carbon and K4-like NaC2 have been studied by performing first-principle calculations. Total energies as functions of isotropic deformations and volume-conserving tetragonal and trigonal deformations have been calculated. For K4 carbon, the total energy shows a minimum for isotropic and trigonal deformations, but exhibits maxima for tetragonal deformation. In contrast, the total energy of K4-like NaC2 shows a minimum under all three deformations. These results indicate that K4 carbon is not a metastable phase, but that K4-like NaC2 is a metastable phase. In addition, the heat of formation of K4-like NaC2 is discussed. 相似文献
78.
Kimitaka Minami Shiori Goto Mehrnoosh Atashfaraz Takanari Togashi Toshihiko Arita Daisuke Hojo Seiichi Takami Tadafumi Adschiri 《Research on Chemical Intermediates》2011,37(2-5):415-419
This paper reports, for the first time, the enhanced dissolution of cellulose in subcritical water by addition of a fatty acid. Simply adding oleic acid dramatically promoted the dissolution of cellulose. High-pressure in-situ observation showed that cellulose dissolved in high-temperature water at approximately 500 K, which is 70 K lower than without oleic acid. The yield of oligo and monosaccharides with oleic acid at 473 K was seven times higher than without oleic acid. 相似文献
79.
Ameneh Sahraneshin Seiichi Takami Kimitaka Minami Daisuke Hojo Toshihiko Arita Tadafumi Adschiri 《Progress in Crystal Growth and Characterization of Materials》2012,58(1):43-50
Organic-functionalized nanoscale yttrium aluminum garnet (YAG) particles were synthesized via a simple rapid supercritical hydrothermal method in the presence of oleylamine and oleic acid as organic surface modifiers. The presence of the organic molecules resulted in the various morphologies of the produced YAG particles, including cubic, spherical and chainlike structures. Because of their hydrophobic surface character, as-synthesized particles were dispersible in organic solvents. 相似文献
80.
In the development of nanoparticle-based vaccine adjuvants, the interaction between nanoparticles (NPs) and the cells is a key factor. To control them, we focused on the relationship between the hydrophobicity of the side chains and the cell membrane. In this study, amphiphilic poly(γ-glutamic acid) (γ-PGA), using various types of hydrophobic side chains, was synthesized and used to prepare NPs for evaluating the membrane disruptive activity. When leucine ethyl ester (Leu), methionine ethyl ester (Met), or tryptophan ethyl ester (Trp) was grafted, each polymer formed monodispersed NPs at physiological conditions. Significantly, NPs composed of Leu and Trp showed a membrane disruptive activity at the endosomal environment (pH 5–6.5), while NPs composed of Met did not show. This might be due to the weak hydrophobicity of Met compared to that of Leu and Trp, which demonstrated that the interaction between NPs and cells could be controlled by designing the polymer compositions. 相似文献