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SUMMARY: This paper presents the development results of a −1 MV dc filter and dc measurement systems for an ITER (International Thermonuclear Experimental Reactor) neutral beam injector (NBI) system. High accuracy of 0.5% and fast responsivity of 3.3 μs, −3 dB are required for the dc measurement systems: both dc voltage dividers and DCCTs. Circuit design and thermal flow design were carried out to clarify and minimize their effects on the accuracy and responsivity. The validity of the established design was demonstrated by the actual‐product tests; temperature rise of each components fell below the allowable value; inner components of dc filter withstood dc −1.2 MV; each voltage divider accurately measured the voltage during the dc −1.2 MV withstand voltage test; the voltage dividers and the DCCTs were adequate to the requirements of responsivity (3.3 μs, −3 dB). [ABSTRACT FROM AUTHOR]

SUMMARY: This paper presents development results of a five‐stage DC‐1MV Ultrahigh Voltage Generator for ITER. Each generator outputs −200 kV, and the total five generators are connected in series and outputs −1 MV. In order to realize the DC‐1MV output and 1‐h continuous operation, a feasibility of both gas insulation and gas cooling for semiconductor devices was validated. A simplified structure with stud‐type diodes and heatsinks resulted in the compatibility of enough insulation distance and wide cooling surface. Withstand voltage tests and a temperature rise test were performed for the actual equipment of the rectifier and the step‐up transformer. These test results verified the validity of the proposed design. [ABSTRACT FROM AUTHOR]

Doxapram is the only dedicated respiratory stimulant used to aid recovery of breathing after major surgery. Doxapram acts on peripheral chemoreceptors and although the central action of doxapram has been suggested, its detailed neuronal mechanism is unknown. We assessed doxapram-induced changes in spontaneous cervical nerve (C4) inspiratory activity and the firing of action potentials in pre-inspiratory and inspiratory neurones in the medulla. Experiments were performed in neonatal rat brainstem-spinal cord preparations, which can produce respiratory rhythm for several hours under in vitro conditions. Doxapram application (for 15 min) increased the frequency and amplitude of C4 activity dose-dependently. Doxapram induced changes in the electrophysiological properties of pre-inspiratory and inspiratory neurones. Our results suggest that respiratory activity enhancement was likely to be induced via effects on the potassium channels of pre-inspiratory and inspiratory neurones and indicate the central actions of doxapram. [ABSTRACT FROM AUTHOR]

Hatching responses of the Japanese whiting, Sillago japonica Temminck et Schlegel, to a series of temperature changes were measured by exposing the fertilized eggs to eight constant incubation temperatures which ranged from 20.0 to 34.0°C. For a control, hatching temperature was kept the same as temperature of the ambient environment. Hatching responses were expressed as hatching percentages. Altogether 18 experimental trials were conducted during the natural spawning season of the species which extended over a period of 2 months from late July to mid-September 1988, when seawater temperature varied between 24.0 and 30.0°C. Optimum and limiting temperatures were recorded and the data were optimally fit to the quadratic model. Results indicated that viable hatch occurred at almost all ranges of hatching temperature from 22.0 to 32.0°C. However, no hatching was recorded at either 20.0 or 32.0°C. The experiment showed that the optimum hatching temperature varied with the ambient temperature changes during the spawning season, indicating the latter to be a dependent factor for any hatching success. [ABSTRACT FROM AUTHOR]