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991.
A three-waveguide coupler, combining directional and contradirectional coupling between the central and side waveguides, respectively, is discussed. Coupled-mode formalism is used to examine the superposed processes both in synchronism and near synchronism. The nature of the solution is shown to depend on the relative coupling strengths of the individual processes. For stronger contradirectional coupling, the power is divided among the three output ports, at ratios closely related to the ratio of the coupling coefficients, and with a nonperiodic, slowly varying length dependence. The coupler can thus be used as a power divider without the need for a precisely special case where the directional and contradirectional coupling coefficients are equal 相似文献
992.
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
993.
Mass transport in wood during drying can have different mechanisms at different periods of drying. Depending on the current moisture content (MC) and the structure of the wood, the driving forces for the mass transport are essentially different. Above the fiber saturation point (FSP), the lumens are partially saturated and the transport of liquid (free) water occurs as a consequence of capillary action. On the other hand, below the FSP, bound water within the cell walls is conveyed by diffusion, and water vapor in the lumens moves under influence of pressures gradient. Based on these considerations, a unified model is presented that takes into account the transport of the different moisture phases. Simulation of the drying of a Norway spruce sample at 50°C from about 135 to 7% MC is carried out using the finite element method (FEM). Comparison between the simulated average MC and the experimental observations obtained from X-ray computed tomography (CT) shows reasonable agreement. Possible simplifications in the model are briefly discussed as well as some aspects of the numerical implementation. Finally, the influence of absolute permeability on the average MC is studied. 相似文献
994.
995.
996.
Salmonella strains exposed to lethal doses of gamma radiation are detoxified but retain their antigenic properties. Using eight Salmonella strains representative of each of the Salmonella serogroups A to G, a polyvalent radiovaccine has been developed which effectively immunizes mice to several Salmonella serotypes. 相似文献
997.
The secondary effluent from municipal plants in Korea generally represents higher BOD with lower SS. Therefore, more soluble forms of organics and NH4-N need to be removed to improve its effluent for reuse. In this study reuse possibility of secondary effluent and CSO (combined sewer overflow) using BAF (biological aerated filter) was evaluated. The tertiary application with 1.2 h EBCT, SS, BOD and COD showed stable concentrations less than 1.3, 1.3 and 6.2 mg/L, respectively. Nitrogen could be nitrified even at 7 degrees suggesting BAF can be used for a water reuse method as well as an effective add-on facility in cold regions. However, BAF was not stable with CSO application at increased flow rates suggesting CSO must be equalised prior to application. Disinfection was necessary even during normal weather conditions. 相似文献
998.
Wang K.C. Asbeck P.M. Chang M.F. Sullivan G.J. Miller D.L. Basit H.F. 《Electronics letters》1989,25(17):1111-1112
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
999.
Rosen A. Stabile P.J. Gombar A.M. Janton W.M. Bahasadri A. Herczfeld P. 《Photonics Technology Letters, IEEE》1989,1(6):132-134
A two-dimensional laser array, delivering a peak power of 1 kW with an overall efficiency of 33%, was used to activate silicon p-i-n diodes. A single device, activated by a 1 kW laser, produced a holding voltage of 1000 V and conducted 56 A. When two similar p-i-n diodes were connected in parallel and activated by two 1 kW AlGaAs laser arrays, a holding voltage of 1000 V and conduction of 100 A were obtained 相似文献
1000.
L Rudzik E Wüst F J Laven U Marquardt 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1987,185(4):271-274
The theory of deconvolution of infra-red spectra is presented and illustrated using milk protein spectra. The advantage of this method is impressively demonstrated and its relevance for dairy farming shown using a simple example, the cooling of milk. 相似文献