Laser detection of latent fingerprints: preparation of fluorescent dusting powders and the feasibility of a portable system.
A simple procedure for the preparation of dusting powders with a variety of fluorescent colors is described. Such powders permit detection of latent prints by laser even when the surfaces holding the latent prints luminesce strongly. A possible portable laser detection system is also suggested.
The effects of the argon lon laser on subsequent blood examinations.
Dried bloodstains on cotton sheeting ranging in age from three days to three months were exposed to the argon ion laser for durations from 30 s to 3 main. The bloodstains showed greatly reduced reactions or none at all with presumptive reagents applied by fine mist spraying. Filter paper rubs of the same stains followed by presumptive testing yielded the appropriate oxidation reactions of the indicator reagents.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.