- 著者
- Ichiro SUNAGAWA Yasushi TAKAHASHI Hiroyuki IMAI
- 出版者
- Japan Association of Mineralogical Sciences
- 雑誌
- Journal of Mineralogical and Petrological Sciences (ISSN:13456296)
- 巻号頁・発行日
- vol.102, no.3, pp.174-181, 2007 (Released:2007-07-03)
- 参考文献数
- 20
- 被引用文献数
- 35 39
Alternating layers of calcite and aragonite, precipitated from mineral spring in fracture zones of serpentine mass, occur at Kashio, Oosika mura, Nagano Prefecture, Japan. Element mapping by means of Micro-area X-ray Fluorescence (MXRF) conclusively demonstrated that strontium concentrates more in aragonite layer, and not in calcite layer. Other elements including magnesium show no positive correlation with aragonite precipitation. MXRF analyses of aragonite samples from other localities and origins also indicated concentration of Sr as major impurity component, demonstrating that Sr plays essential role in metastable nucleation of aragonite in the precipitation of CaCO3 polymorphs from aqueous solution. This can be understood on the basis of modifications of surface energy term in CaCO3 nucleation in the presence of Sr. Temperature changes trigger to increase the Sr concentration in mineral spring, leading to metastable nucleation of aragonite.
1 0 0 0 An Analysis on Single Wavelength Oscillation of Semiconductor Laser at High Speed Pulse Modulation
- 著者
- Kenichi IGA Yasushi TAKAHASHI
- 出版者
- The Institute of Electronics, Information and Communication Engineers
- 雑誌
- IEICE TRANSACTIONS (1976-1990) (ISSN:00000000)
- 巻号頁・発行日
- vol.E61-E, no.9, pp.685-689, 1978-09-25
In this paper, an analysis was made on the variation of oscillating mode numbers of a semiconductor laser at high speed pulse modulation by solving multi-mode rate equations which relate a quasi-Fermi level to photon numbers. The laser gain was assumed to be homogeneous and has a dependency of (), where is ωEg (relative photon energy). Single mode oscillation conditions for short pulse modulation were obtained associated with following two cases. A) One is the criterion how wide the mode separation must be made as of a short cavity laser and of an integrated twin-guide (ITG) laser. B) The other is the condition how large we must give an excess loss to the unwanted modes such as of the ITG laser, of a distributed feedback (DFB) laser, and of a distributed Bragg reflector (DBR) laser.