Self-Excited Oscillations in a System with Two Degrees of Freedom

The behavior of a negative-resistance oscillator with two resonant circuits is studied. The amplitude and frequency characteristics of the self-excited oscillation are calculated and shown graphically for some combinations of the system parameters. The stability of the oscillation is discussed. Particular attention is directed toward the internal resonance of the two resonant circuits which occurs when a certain relationship exists between their natural frequencies

Homoptera-Auchenorrhyncha and Heteroptera(Insecta,Rhynchota)from Sugadaira,Central Honshu,Japan

Through recent field researches to clarify the Rhynchota fauna, 378 species are recognized and recorded from Sugadaira, Nagano Prefecture, central Honshu.They comprise 218 Homoptera-Auchenorrhyncha and 160 Heteroptera including 21 species new to Japan. A brief note on taxonomy and/or ecology is also given for some species. Key words : Homoptera-Auchenorrhyncha, Heteroptera, fauna, list, Sugadaira, Japa

Adsorption characteristics of bovine serum albumin onto alumina with a specific crystalline structure

Bone cement containing alumina particles with a specific crystalline structure exhibits the ability to bond with bone. These particles (AL-P) are mainly composed of delta-type alumina (δ-Al2O3). It is likely that some of the proteins present in the body environment are adsorbed onto the cement and influence the expression of its bioactivity. However, the effect that this adsorption of proteins has on the bone-bonding mechanism of bone cement has not yet been elucidated. In this study, we investigated the characteristics of the adsorption of bovine serum albumin (BSA) onto AL-P and compared them with those of its adsorption onto hydroxyapatite (HA), which also exhibits bone-bonding ability, as well as with those of adsorption onto alpha-type alumina (α-Al2O3), which does not bond with bone. The adsorption characteristics of BSA onto AL-P were very different from those onto α-Al2O3 but quite similar to those onto HA. It is speculated that BSA is adsorbed onto AL-P and HA by interionic interactions, while it is adsorbed onto α-Al2O3 by electrostatic attraction. The results suggest that the specific adsorption of albumin onto implant materials might play a role in the expression of the bone-bonding abilities of the materials

阪大法学 66巻 3,4号 巻頭の辞

松川正毅教授退職記念