The Basalt of Patagonia

The samples subjected to the microscopic examination and chemical analysis were provided by the 4th Scientific Expedition to Patagonia by Hiroshima & Hokkaido Univ., 1969. The party collected them on the continental side of the southern Andes between Mendoza and Santa Cruz in Argentina. The present writers tried in the first place to clarify the order of eruption, in the second place to define the petrological and chemical properties of the basalts, and at last some genetic considerations were pursued

The Magnetic and Electric Properties of (Co_<1-x> Mn_x)_2B Crystalline compounds and Amorphous Alloys

The manganese concentration x dependence of the average magnetic moment μo, the Curie temperature Tc, the pressure effect on Tc and the electric resistance for the ferromagnetic amorphous alloys (Co_ Mn_x)B were investigated. The Curie temperature decreases linearly with increasing x and μo had a maximum around x=0.15. The magnetic susceptibility vs. temperature curves for all the prepared amorphous alloys obey the Curie-Weiss law above Tc. The pressure effect on Tc is that Tc has a value of 1.06 K/kbar at x=0 and is decreasing with increasing x and becomes zero at x=0.4. These results are analyzed on the basis of the pair interaction model and the local enviroment effect. There arise two kinds of minimum in the resistance vs. temperature curves. That the resistance minimum at high temperature has a strong correlation with Tc is assured by measuring the transverse effect of the resistance with amorphous alloys x=0.4. The resistance minimum for the amorphous alloys and crystalline compounds are found at low temperature under ferromagnetic state

Leonid Meteor Observer in LEO: A University Microsatellite to Observe a Meteor Shower from Space

This paper presents university-based design and development of a micro-satellite for the observation of a meteor shower from the low Earth orbit. The satellite will be launched as a piggy-back payload of a commercial rocket launcher, a few weeks before the 2001 or 2002 Leonid meteor maximum in which thousands of meteors are scienti_cally expected. The goal of the mission is to conduct the scienti_c observation of the prospective meteor outburst from out of atmosphere, counting the meteors in the large coverage of the night sky looked down on Earth and obtaining visible-Ultra Violet spectrographs of the meteor. Possible launch opportunity remains to be seen, but the designs of the satellite bus and scientific payloads are now initiated

Resorption of apatite-wollastonite containing glass-ceramic and beta-tricalcium phosphate in vivo.

Apatite-wollastonite containing glass ceramic is considered to be difficult to resorb, but we experienced the disappearance of the porous type of Apatite-wollastonite glass ceramic particles . In this study, the resorption of porous apatite-wollastonite glass-ceramic implanted in the femurs of rabbits was investigated, and the process was compared with beta-tricalcium phosphate, a resorbable ceramics. Porous apatite-wollastonite glass-ceramic (70, 80, and 90% porosity) and beta-tricalcium phosphate (75% porosity) were implanted in the femurs of Japanese white rabbits. Samples were harvested and examined 0, 4, 8, 12, 24 and 36 weeks after implantation. Quantitative analysis of the radiographic and histologic findings was performed with NIH Image software. Radiographic examination demonstrated that the radiopacity and size of the porous apatite-wollastonite glassceramic cylinders decreased gradually after implantation. Histologic examination revealed that the surface area of the apatite-wollastonite glass-ceramic cylinders decreased continuously, and approached 20% of the original area 36 weeks after implantation. However, the resorption rate of porous apatite-wollastonite glass-ceramic was slower than that of beta-tricalcium phosphate. Toluidine blue staining showed abundant new bone formation on the surface of the apatite-wollastonite glassceramic matrix. Considering its mechanical strength, gradual resorption characteristics, and good osteochonductive activity, porous apatite-wollastonite glass-ceramic appears to be a suitable artificial bone substitutes.</p