High-temperature optically activated GaAs power switching for aircraft digital electronic control

Gallium arsenide high-temperature devices were fabricated and assembled into an optically activated pulse-width-modulated power control for a torque motor typical of the kinds used in jet engine actuators. A bipolar heterojunction phototransistor with gallium aluminum arsenide emitter/window, a gallium arsenide junction field-effect power transistor and a gallium arsenide transient protection diode were designed and fabricated. A high-temperature fiber optic/phototransistor coupling scheme was implemented. The devices assembled into the demonstrator were successfully tested at 250 C, proving the feasibility of actuator-located switching of control power using optical signals transmitted by fibers. Assessments of the efficiency and technical merits were made for extension of this high-temperature technology to local conversion of optical power to electrical power and its control at levels useful for driving actuators. Optical power sources included in the comparisons were an infrared light-emitting diode, an injection laser diode, tungsten-halogen lamps and arc lamps. Optical-to-electrical power conversion was limited to photovoltaics located at the actuator. Impedance matching of the photovoltaic array to the load was considered over the full temperature range, -55 C to 260 C. Loss of photovoltaic efficiency at higher temperatures was taken into account. Serious losses in efficiency are: (1) in the optical source and the cooling which they may require in the assumed 125 C ambient, (2) in the decreased conversion efficiency of the gallium arsenide photovoltaic at 260 C, and (3) in impedance matching. Practical systems require improvements in these areas

Coherence in the age of statutes

The High Court of Australia, in pursuing coherence between common law and statute law, has limited itself to ensuring that the rules of common law and statute law should be free of contradiction. The Court does not appear to have embraced the idea, which lies at the core of some major theories of private law, that a set of rules is coherent only if the set can be explained as the outworking of a single principle. Applying that idea to the relationship between common law and statute law is confronted by some serious challenges. In the past, coherence as non-contradiction (combined with the idea of parliamentary supremacy) has worked well as a means of reconciling common law with statute law, but the proliferation of legislation in recent years and the character of much modern legislation has drawn attention to the limitations of such an approach to the question. A more exacting approach to coherence of common law and statute law, on the other hand, would require the revision of some widely held assumptions about the nature of law, such as the core assumption of legal positivism that the ultimate criterion of the authority of the law is its pronouncement by an authoritative institution

Effects of a community-based approach of food and psychosocial stimulation on growth and development of severely malnourished children in Bangladesh: a randomised trial.

BACKGROUND/OBJECTIVE: Psychosocial stimulation (PS) and food supplementation (FS) improve development of malnourished children. This study evaluates the effects of a community-based approach of PS and FS on growth and development of severely malnourished children. SUBJECTS/METHODS: Severely underweight hospitalised children aged 6-24 months (n = 507) were randomly allocated on discharge to five groups: (i) PS, (ii) FS, (iii) PS+FS, (iv) clinic-control and (v) hospital-control. PS included play sessions and parental counselling on child development. This was done at each fortnightly follow-up visit, that is, every second week, for 6 months at community clinics. FS included distribution of cereal-based food packets (150-300 kcal/day) for 3 months. All groups received medical care, micronutrient supplementation, health-education and growth monitoring. Children's development was assessed using revised version of Bayley Scales of Infant Development at baseline and after 3 and 6 months of intervention. Anthropometry was measured using standard procedure. RESULTS: Comparing groups with any stimulation with those with no stimulation there was a significant effect of stimulation on children's mental development index (group*session interaction P = 0.037, effect size = 0.37 s.d.) and weight-for-age Z-score (group*session interaction P = 0.02, effect size=0.26 s.d.). Poor levels of development and nutritional status were sustained, however, due to their initial very severe malnutrition. There was no effect on motor development and linear growth. CONCLUSION: Children receiving any stimulation showed a significant benefit to mental development and growth in weight. More intensive intervention with longer duration is needed to correct their poor developmental levels and nutritional status

Neoproterozoic to Cambrian granitoids of northern Mozambique and Dronning Maud Land Antarctica.

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月17日（木） 国立極地研究所　2階大会議

A Complete Dynamic Model for a PWM VSI-fed rotor flux oriented vector controlled Induction Motor Drive using SIMULINK

Abstract