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991.
Gail H. Marcus 《Petroleum Science and Technology》1987,5(4):387-439
This paper documents and analyzes recent trends in Federal energy research and development programs. In light of the marketplace philosophy of the present Administration, the possible benefits of a strong Federal research program versus the potential advantages of relying on private sector research programs to develop new technology alternatives are analyzed in some detail. The impacts of the Reagan budget cuts and other initiatives on several major energy programs, including nuclear power, photovoltaics, and conservation, are also analyzed. This analysis reveals some of the difficulties inherent in attempting to project the consequences of particular policy decisions in a complex and changing environment, and identifies some of the problems of trying to evaluate the success of particular programs or actions on a limited time scale. 相似文献
992.
993.
A design method for tuning of multivariable PI-controllers for possibly unknown linear time-invariant delay-differential systems is presented. The plant is assumed to be stable with input and output delays and subject to step disturbances. The multivariable PI-controller may be tuned with the aid of open-loop step responses. The stability and robustness of the control law is discussed and an example is given to show the applicability of the controller. 相似文献
994.
Hwang H.-K. Lee L.-S. Chen S.-H. 《Selected Areas in Communications, IEEE Journal on》1989,7(9):1450-1461
Multi-H phase-coded modulation (MHPM) is a bandwidth-efficient modulation scheme which offers substantial coding gain over conventional digital modulation schemes. MHPM with asymmetric modulation indices corresponding to the bipolar data +1 and -1 is considered, and numerical results for the minimum Euclidean distances are provided. It is shown that performance improvements on the error probability over conventional MHPM are gained with essentially the same bandwidth and a very slight modification in implementation. The upper bounds on the error probabilities as functions of observation intervals and received E b/N 0 are also investigated in detail. It is concluded that the concept of asymmetric modulation indices for MHPM is attractive for bandwidth and power-efficient modulation 相似文献
995.
I Kaufmann T Meyer M Kalsch T G Schmitt H W Hamacher 《Water science and technology》2007,56(5):115-124
If technologies for decentralised sanitation and reuse (DESAR) and for natural stormwater management should at least partially replace existing systems, then intensive reconstruction work becomes essential. A conversion can only be realised successively over a long period due to high construction and financial expenses and requires new strategies. This paper presents the development and practical implementation of a mathematical tool to find an optimised strategy for the realisation of alternative and more decentralised drainage and sanitation concepts in existing urban areas. The succession of construction measures (e.g. the implementation of decentralised greywater recycling) for the whole period of consideration is determined based upon a mathematical optimisation model on the condition that the favoured future state is known. The model describes the complex interdependencies of the urban water and nutrient cycle and enables the minimisation of both financial efforts and ecological impacts on the way toward the future state. The results of the implementation for a rural area in Germany show that the mathematical optimisation is an adequate instrument to support decision-making processes in finding strategies for the realisation of sustainable urban water management. 相似文献
996.
997.
A compact Ku -band phase-locked oscillator module has been developed in a full MMIC (monolithic microwave integrated circuit) configuration. The module includes an MMIC voltage-controlled oscillator, an analog frequency divider, and interstage amplifiers. The constituent monolithic chips are integrated in a very small single-package module and operate at the target frequencies without any external trimming or matching network. The oscillator is tuned more than 1 GHz with a constant output amplitude. The frequency-divided output is also obtained over the whole tuning range. Spurious output is not found at any frequency up to 22 GHz. In spite of the very low-Q factor of GaAs monolithic circuitry, the oscillator phase noise exhibited is less than -80 dBc/Hz, due to the high-gain, high-speed phase lock 相似文献
998.
H H T?nnesen J Karlsen 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1985,180(5):402-404
The kinetics of the pH-dependent degradation of curcumin has been investigated. A plot of the rate constant against pH indicates the pKa values of the acid protons. The graph also indicates the complexity of the curcumin degradation. 相似文献
999.
A previous study of three potato varieties indicated that shear force measurement may be used to predict the behavior of certain potato properties during cooking. To verify this hypothesis and to confirm other previous findings, slices (6 mm thick, 30 mm in diameter) of 21 potato varieties were thermally treated in water at 100°C. Mathematical expressions were assessed, and coefficients were determined to describe the kinetic behavior of the varieties. 相似文献
1000.
H. YOUNG P. FELLOWS J. MITCHELL 《International Journal of Food Science & Technology》1985,20(6):689-695
International aid agencies undertake supplementary feeding programmes following disasters in order to alleviate or prevent protein energy malnutrition. The associated problems include lack of facilities for preparation and distribution of food on site and food hygiene dangers. In response to these factors a biscuit of high calorific value and acceptable organoleptic qualities has been developed. It is currently being used by Oxfam as part of their disaster relief programme in Ethiopia. 相似文献