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971.
Several railgun experiments designed to accelerate projectile masses of 2 to 5 g to velocities greater than 6 km/s were performed. Two parallel rail-type accelerators with 12.7 mm square bores were used for the experiments. One gun is 2 m long, has molybdenum rails and alumina ceramic insulators. The other is 1 m long, has molybdenum rails and granite insulators. The greatest velocity achieved to date during the experiments was 5.1 km/s. During the test program, the following ideas to enhance launcher performance were tested: stiff-gun structures to reduce plasma leakage and rail movement, refactory bore materials to reduce ablation and frictional losses, and prefilling the gun bore with gases which will eliminate precursor arcs. After three experiments utilizing the 2 m long launcher, with peak currents ranging from 660 to 780 kA, a gun barrel comprised of 96% pure alumina ceramic insulators and 99.9% pure molybdenum rails has survived with minimal damage and no degradation of seals  相似文献   
972.
As far as flocculation is concerned, the agglomeration of suspended particles into flocs is highly linked to the hydraulic behaviour of the agitation. The Turbomix is a special design of mixing tank; its design was developed to better control the flow during the flocculation stage. It enables a significant decrease in footprint of the process. The combination of the Turbomix and ballasted flocculation has been studied during pilot trials in terms of treatment efficiency. Its controlled hydraulic behaviour explains the efficiency of the process as proved by CFD investigation.  相似文献   
973.
Decentralised systems have the potential to provide a viable option for long term sustainable management of household wastewater. Yet, at present, such systems hold an uncertain status and are frequently omitted from consideration. Their potential can only be realised with improved approaches to their management, and improved methods to decision-making in planning of wastewater systems. The aim of this paper is to demonstrate the value of a novel framework to guide the planning of decentralised systems so that asset management and risk management are explicitly considered. The framework was developed through a detailed synthesis of literature and practice in the area of asset management of centralised water and wastewater systems, and risk management in the context of decentralised systems. Key aspects of the framework are attention to socio-economic risks as well as engineering, public health and ecological risks, the central place of communication with multiple stakeholders and establishing a shared asset information system. A case study is used to demonstrate how the framework can guide a different approach and lead to different, more sustainable outcomes, by explicitly considering the needs and perspectives of homeowners, water authorities, relevant government agencies and society as a whole.  相似文献   
974.
Components of dietary fiber (soluble nonstarch polysaccharide, pectin, hemicellulose, cellulose and lignin), water, energy, protein, lipid and starch were measured in banana, breadfruit, cassava, coconut, mango, pawpaw, plantain, sweet potato, taro and Pacific yam, all from the Pacific Island Kingdom of Tonga. The Tongan foods were generally higher in dietary fiber than New Zealand foods, consistent with the hypothesis that dietary fiber is an important factor contributing to a lower incidence of certain gastrointestinal disorders in Tonga, than in New Zealand.  相似文献   
975.
976.
Zusammenfassung Der Gehalt an Nitrosoaminosäuren und ihr Anteil an den Gesamt-N-Nitrosoverbindungen im Fettgewebe von rohem Schinkenspeck wurde untersucht. In 80% der Proben wurde ein Gehalt an Nitrosoaminosäuren von bis zu 0,2 mg/kg festgestellt. Scheinbare Gesamt-N-Nitrosoverbindungen waren in allen Proben in einer Konzentration von 0,4 bis 3,7 mg (N-NO)/kg vorhanden. Die eigentlichen Nitrosoaminosäuren machen nur etwa 1% der scheinbaren Gesamt-N-Nitrosoverbindungen aus. Die Mehrzahl der scheinbaren Gesamt-N-Nitrosoverbindungen im Fettgewebe findet sich im nichtlöslichen Bindegewebe, wobei der verbleibende Rest chloroformlöslich ist.Summary The levels of nitrosoamino acids and apparent total N-nitroso compounds in the adipose tissue of raw bacon have been examined. Nitrosoamino acids were detected in 80% of the samples in levels of up to 0.2 mg/kg. Apparent total N-nitroso compounds were present in all samples in concentrations of between 0.4 and 3.7 mg (N-NO)/kg. Nitrosoamino acids accounted for approximately only 1 % of the apparent total N-nitroso compounds. The majority of the apparent total N-nitroso compounds in the adipose tissue were associated with the insoluble connective tissue fraction, with the remainder present as chloroform soluble species.
Einige Nitrosoaminosäuren im fettgewebe von Schinkenspeck und ihr anteil an der Konzentration der Gesamt-N-Nitrosoverbindungen
  相似文献   
977.
Smoke-haze episodes caused by vegetation and peat fires affect parts of Indonesia every year with significant impacts on human health and climate. The forest fires 1997/1998 were by far the largest in Indonesian history, burning between 5 and 8 million hectares before they were stopped by the monsoon rains in December 1997. Fires sprang up again in 1998 on Kalimantan when monsoon rain paused. Peat forests and peatlands are in particular severely affected. In the 1997/1998 haze event, 2.1-2.5 million hectare of peat swamp forest burnt in Indonesia. The remaining ash contains high concentrations of sulphur and sulphuric compounds which eventually leach into the groundwater, thus polluting groundwater and drinking water. The thicker the peat layer is and the higher the number of fires in the respective area the more sulphuric compounds will leach into the groundwater. Risk areas for the sulphur loads of the ash are identified.  相似文献   
978.
The authors report a novel noninterfering and simple approach for evaluation of circuits implemented with AlGaAs/GaAs heterojunction bipolar transistors (HBTs). This method makes use of radiative recombination in the base region of current-carrying HBTs. The infrared radiation emitted is 'visible' to the closed-circuit TV (CCTV) cameras. Therefore, one can view the operation of the HBT circuit under test at normal biases with a TV monitor. This method can be used to determine logic states of gates, as well as collector current of individual HBTs within integrated circuits.<>  相似文献   
979.
Narrow pulse measurement of drain characteristics of GaAs MESFETs   总被引:2,自引:0,他引:2  
A measurement technique is presented which uses narrow, fast-rise-time pulses applied to both the gate and the drain of a GaAs MESFET to obtain the drain characteristics of the device. This allows the characteristics of the device to be obtained which correspond to frequencies above those at which surface and substrate traps can respond. The resulting characteristics show significant departures from those obtained using conventional long pulse and DC measurement techniques.  相似文献   
980.
Findings of 7 studies suggested that decisions about the sex of a face and the emotional expressions of anger or happiness are not independent: Participants were faster and more accurate at detecting angry expressions on male faces and at detecting happy expressions on female faces. These findings were robust across different stimulus sets and judgment tasks and indicated bottom-up perceptual processes rather than just top-down conceptually driven ones. Results from additional studies in which neutrally expressive faces were used suggested that the connections between masculine features and angry expressions and between feminine features and happy expressions might be a property of the sexual dimorphism of the face itself and not merely a result of gender stereotypes biasing the perception. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
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