A molecular dynamics simulation of hexagonal solid platinum nanowires

Experimental evidence of the existence of multi-wall platinum (Pt) nanowires (NWs) has been reported. In this paper, we investigated structural formation of Pt NWs using the classical molecular dynamics (MD) simulation method. The simulations began from initial configurations with random distributions of atomic positions. The initial configuration was minimised by the steepest descent method, and assigned a temperature of 601?K with a random distribution of atomic velocities. Then simulated annealing was applied such that the temperature of the system was reduced gradually to 1?K and a stable NW structure was obtained. Types of hexagonal solid Pt NWs featuring different structures than those of previously reported NWs were found. Details of structural characteristics and mechanical properties of these Pt NWs are presented.     

A battery-powered three-mode temperature-controller circuit

This paper describes the design and operation of a three-mode (i.e. proportional, rate and reset response) controller which can supply several amperes at 0–24 V to a resistance heater. This circuit was designed to control taxidermic mounts used to measure standard operative temperature. It is suitable for other applications requiring regulation of a low-voltage (<24 V) heater where there is an appreciable time delay in sensing the regulated temperature.     

Minimal changes in hypothalamic temperature accompany microwave-induced alteration of thermoregulatory behavior

This study probed the mechanisms underlying microwave-induced alterations of thermoregulatory behavior. Adult male squirrel monkeys (Saimiri sciureus), trained to regulate the temperature of their immediate environment (Ta) behaviorally, were chronically implanted with Teflon reentrant tubes in the medical preoptic/anterior hypothalamic area (PO/AH), the brainstem region considered to control normal thermoregulatory processes. A Vitek temperature probe inserted into the tube measured PO/AH temperature continuously while changes in thermoregulatory behavior were induced by either brief (10-min) or prolonged (2.5-h) unilateral exposures to planewave 2,450-MHz continuous wave (CW) microwaves (E polarization). Power densities explored ranged from 4 to 20 mW/cm2 (rate of energy absorption [SAR] = 0.05 [W/kg]/cm2]). Rectal temperature and four representative skin temperatures were also monitored, as was the Ta selected by the animal. When the power density was high enough to induce a monkey to select a cooler Ta (8 mW/cm2 and above), PO/AH temperature rose approximately 0.3 degrees C but seldom more. Lower power densities usually produced smaller increases in PO/AH temperature and no reliable change in thermoregulatory behavior. Rectal temperature remained constant while PO/AH temperature rose only 0.2-0.3 degrees C during 2.5-h exposures at 20 mW/cm2 because the Ta selected was 2-3 degrees C cooler than normally preferred. Sometimes PO/AH temperature increments greater than 0.3 degrees C were recorded, but they always accompanied inadequate thermoregulatory behavior. Thus, a PO/AH temperature rise of 0.2-0.3 degrees C, accompanying microwave exposure, appears to be necessary and sufficient to alter thermoregulatory behavior, which ensures in turn that no greater temperature excursions occur in this hypothalamic thermoregulatory center.