巻号一覧
36 巻, 6 号
選択された号の論文の9件中1～9を表示しています
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腰原 伸也2008 年 36 巻 6 号 p. 330-331
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーPDF形式でダウンロード (232K) -
板谷 治郎, 沖本 洋一, 腰原 伸也2008 年 36 巻 6 号 p. 332-338
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーPhoto-induced phase transition (PIPT) often results from the imbalance of large coupling between various freedoms in strongly correlated materials. Ultrafast and ultra-broad optical techniques that span from terahertz to x rays are extremely useful to probe PIPT dynamics since they can unfold the complicated processes along the time hierarchy. Furthermore, the recent development of novel intense optical pulses in infrared and THz regions is opening new opportunities to induce and control PIPT. In this review, Iwill report the new trends of novel ultrafast pump-probe techniques using lasers and synchrotrons, most of which are demonstrated at Lawrence Berkeley National Laboatory in the United States.抄録全体を表示PDF形式でダウンロード (1644K) -
中村 敏和, 古川 貢2008 年 36 巻 6 号 p. 339-342
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーIn this paper, we introduce the electronic states and electronic properties of molecular solid especially charge transfer salts and radical salts in the aspect of photo-induced phase transition and related phenomena. The characteristic features of molecular solid, which deeply related to photo-induced phase transition, are as following:(1) low-dimensional electronic states originated from anisotropic interaction,(2) strong electronic correlation induced by low carrier concentration,(3) lattice softness which causes competition of electronic phases with pressure and thermal contraction,(4) internal-freedom, namely, molecular motions. We propose strategies for exploring possible candidates for forthcoming materials with photo-induced phase transition.抄録全体を表示PDF形式でダウンロード (970K) -
コヒーレント振動と過渡状態米満 賢治2008 年 36 巻 6 号 p. 343-348
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーTheoretical understanding of photoinduced phase transitions and their dynamics is reviewed from the viewpoint of coherent oscillations and transient states in condensed molecular materials with quasi-one-dimensional electronic conduction. In the mixed-stack organic charge-transfer compound TTF-CA (TTF: tetrathiafulvalene, CA: chloranil), the photoinduced transition from the ionic phase to the neutral phase is accompanied with coherent motion of a neutral-ionic domain boundary. Its high cooperativity is realized by the sufficiently strong, interchain Coulomb coupling in the ionic phase. In the quarter-filled-band organic salt (EDO-TTF) 2PF6 (EDO: ethylenedioxy), the photoinduced melting of charge order is accompanied with oscillations in transient reflectivity. The degree of coherence in these oscillations depends on the probe photon energy. It is caused by different space and time scales of observed electronic motion and relevant phonon motion.抄録全体を表示PDF形式でダウンロード (1312K) -
富永 淳二, フォンズ ポール, コロボフ アレキサンダー2008 年 36 巻 6 号 p. 349-356
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーIn optical phase-change materials, especially, Ge2Sb2Te5 has widely been used as a heat of rewritable optical storage media. The chalcogenide material shows a good performance in write-erase cyclability and optical contrast: refractive index change between amorphous and crystal state. However, the high-speed switching mechanism has long been not well understood because of the difficulty of the amorphous analysis. In 2004, we gave one solution for the issue. Since then, a number of discussions and critics have raised up on the new model because the amorphous state in the model is not amorphous like. In this review, we want to give a clear solution to understand what is amorphous in chalcogenides and how different is the amorphous from normal glass amorphous.抄録全体を表示PDF形式でダウンロード (4778K) -
武貞 正樹2008 年 36 巻 6 号 p. 357-361
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーThe laser-light refraction method has been performed to investigate the photo-induced cooperative phenomena of an early stage of ferroelasitc and ferroelectric domain formation on KD3 (SeO3) 2 (DKTS) and Rochelle salt (RS) crystals. The refracted light intensity has been observed around the Curie point (Tc). The each temperature dependence of the refracted light intensity under UV irradiation with wavelength of 266nm for DKTS and 400nm for RS with 130fs pulse width shows drastic photoinduced effect in comparison with a non UV irradiation condition. The results clearly demonstrate that the pulsed UV laser irradiation produces a large effect in the embryonic fluctuation near Tc as a photoinduced cooperative phenomenon.抄録全体を表示PDF形式でダウンロード (1373K) -
中村 一隆2008 年 36 巻 6 号 p. 362-366
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーStudied on dynamics of phase transition and structural deformation of materials under laser-induced shock compression have been reviewed. Picosecond time-resolved X-ray diffraction has been performed on analysis of transient crystal structure of semiconductors under shock induced high pressures using pulsed X-rays from laser-plasma and synchrotron radiation. Nanosecond time-resolved coherent anti-Stokes Raman spectroscopy has been performed on shock-induced liquid-solid phase transition of benzene.抄録全体を表示PDF形式でダウンロード (1217K) -
櫻井 康隆, 矢部 孝, 生田 一成, 佐藤 雄二, 内田 成明, 松永 栄一2008 年 36 巻 6 号 p. 367-373
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーBasic characteristics of magnesium, Mg, “combustion” with water vapor were investigated and reported here. The reaction has been proposed as an energy retrieval process that is a part of a solar energy cycle using solar pumped lasers as the energy conversion device. The reaction produces both heat and hydrogen, H2, that can be used either as mechanical (hydrodynamic) or electrical power generation depending on the reaction temperature. This paper describes the dynamics of mechanical power generation where both Mg and H2 combustion energies are retrieved through hydrodynamic motion of water vapor. Dynamics of the reactions are investigated experimentally and compared to a simple model of Mg fuel pellet reaction with water vapor. Both experimental data and theoretical analysis was used to find the optimum mixture ration of Mg and water for momentum generation.抄録全体を表示PDF形式でダウンロード (5057K) -
小澤 祐貴, 張本 鉄雄, 山川 考一2008 年 36 巻 6 号 p. 374-378
発行日: 2008/06/15
公開日: 2014/03/26
ジャーナル フリーWe present numerical and analytical results for the phase-shift dependence of the amplified seed pulse in optical parametric chirped-pulse amplification on the initial phase-mismatching factor on the basis of nonlinear wave equations and small-signal approximation. Numerical and analytical results showed that the phase shift of the amplified seed pulse can be estimated by the initial phase-mismatching factor and the thickness of the nonlinear optical crystal. The corresponding analytical expression for the phase shift shown in this paper is simple and practical for optimizing optical parametric chirped-pulse amplification.抄録全体を表示PDF形式でダウンロード (808K)
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