Advanced optical storage techniques for computers

The growing demand for data storage in computing systems has stimulated the investigation of optical memory techniques because they offer a potential improvement in packing density of about two orders of magnitude over the apparent limits of conventional magnetic storage techniques. Physical properties and optical memory characteristics of magnetooptic thin-films of manganese bismuth have been investigated with regard to both bit-oriented and holographic memories. All the required technology for design of a bit-oriented memory appears to be available, but several key components required for a holographic memory still remain to be developed.

Geometrical interpretation of gaussian beam optics

The relationship between conventional optics and Gaussian beam optics is discussed. Geometrical concepts such as image and object planes, pupil plane, F-number, resolution, and depth of field are discussed for Gaussian beams and are given a precise meaning in terms of the Gaussian beam parameters. The approach is useful in the design of laser scanning systems and holographic optical memory systems.

MnBi Films as Potential Storage Media in Holographic Optical Memories

Because of its alterability and stability, an MnBi thin film is a potential candidate for the storage medium in a read-write-erase in situ holographic optical memory. The conditions and the physical mechanism of holographic storage will be discussed, together with experimental results. A simple holographic memory system will be proposed which uses the same write-in reference beam for readout beam.

Influence of the anterior pituitary on the aldosterone secretory response to dietary sodium restriction in the rat

Studies of the rate of aldosterone production in vitro of adrenals of rats hypophysectomized before dietary sodium restriction showed that hypophysectomy not only prevented the increases in aldosterone production observed in intact, Na-deprived rats, but also depressed the level of aldosterone production to below that of intact rats maintained on a normal diet. Rats hypophysectomized for a similar period of time but maintained on the normal diet showed a similar decrease.

Experiments on adeno- and neuro-hypophysectomized rats indicated that the pituitary factor required for the normal mineralocorticoid response to dietary sodium restriction resides in the anterior pituitary.

Treatment of hypophysectomized rats during dietary sodium restriction with doses of a long-acting corticotrophin (ACTH) prevented adrenal atrophy and maintained a normal glucocorticoid response to intravenous injections of ACTH, but failed to increase aldosterone production rates in vitro to levels above that of intact rats on a normal diet; it also failed to restore the enhanced adrenocortical sensitivity to the stimulating effect of aldosterone production of intravenously injected ACTH which is characteristic of acutely hypophysectomized, Na-deficient rats. Treatment with anterior pituitary powder (8–12 mg./day) for similar periods, however, restored the aldosterone production of adrenals in vitro of hypophysectomized, Na-deprived rats to levels nearly indistinguishable from those of acutely hypophysectomized, Na-deprived controls. The same doses of anterior pituitary powder were shown not to have any demonstrable effect on the aldosterone production of adrenals in vitro of intact rats on a normal diet.

These results are interpreted as indicating the existence of a pituitary factor other than ACTH which stimulates aldosterone secretion. This factor does not appear to act directly on the adrenal cortex or to stimulate the secretion of specific glomerulotropic substances, but probably exerts its effect by maintaining the normal functional capacity of some as yet undefined tissues which secrete glomerulotropic substances in response to dietary sodium restriction.