APPENDIX CONCRETIONS OPAQUE TO X RAYS

Subject headings: galaxies: general—galaxies: spiral—X-rays: general—X-rays: galaxies—X-rays: ISM

We present results from the analysis of deep ROSAT HRI and PSPC observations of the spiral galaxy M81. The inferred total (0.5–2 keV band) luminosity of M81 is ∼ 3×10 ergs s, excluding the contribution from identified interlopers found within the D25 ellipse. The nucleus of the galaxy alone accounts for about 65% of this luminosity. The rest is due to 26 other X-ray sources (contributing ∼ 10%)...

Application of characteristic X-rays to measure linear attenuation coefficient of nano-composites used in shielding

Using of X-rays in different industries and especially in medical application is increasing. In this regard, designing of light and efficient protective material based on polymeric nanocomposites and precise study of the effect of adding nanoparticles with different sizes on the X-ray attenuation is necessary. In this study the epoxy nanocomposites with different percentages of copper oxide nan...

Sensitization to Heat by X-rays

1. Paramecium caudatum is sensitized to heat by sublethal dosages of x-rays. Thus if paramecia are irradiated, then exposed to a sublethal dosage of heat they are killed, but if the same heat exposure precedes the same dosage of radiations, they are not. 2. Sensitivity to both heat and x-rays is much greater in paramecia from the log growth phase than in those from the stationary phase of a cul...

Remembering x-rays.

On the evening of 8 November 1895, ous potential applicability to medical diWilhelm Conrad Rontgen immediately agnosis (2). recognized a remarkable new phenomOn_.zJJ~nu~ry, at his first and only enon. Fluorescent material lying on a public lecture on the discovery, Rontgen bench some distance from the cathode made an x-ray picture of the hand of Dr. ray tube with which he was experimentAlbert v...

Diffraction of X-rays