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991.
992.
Optimum conditions for cementing prepared roofing paper are determined and an installation for laying prepared roofing paper as a hydroinsulating roofing carpet is designed.Gomel Polytechnic Institute. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 63, No. 2, pp. 151–153, August, 1992.  相似文献   
993.
Institute of Mining, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 78–83, January–February, 1991.  相似文献   
994.
995.
996.
On the capacity of a cellular CDMA system   总被引:37,自引:0,他引:37  
It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity  相似文献   
997.
One of the most complicated ANN models, the neocognitron (NC), is adapted to an efficient all-digital implementation for VLSI. The new model, the digi-neocognitron (DNC), has the same pattern recognition performance as the NC. The DNC model is derived from the NC model by a combination of preprocessing approximation and the definition of new model functions, e.g., multiplication and division are eliminated by conversion of factors to powers of 2, requiring only shift operations. The NC model is reviewed, the DNC model is presented, a methodology to convert NC models to DNC models is discussed, and the performances of the two models are compared on a character recognition example. The DNC model has substantial advantages over the NC model for VLSI implementation. The area-delay product is improved by two to three orders of magnitude, and I/O and memory requirements are reduced by representation of weights with 3 bits or less and neuron outputs with 4 bits or 7 bits.  相似文献   
998.
A computerised trace method has been developed for determining the relationships of assembly requirements with design dimensions and tolerances of the components in an assembly, and the relationships of design specifications and machining allowance requirements with manufactured dimensions and tolerances of the component in a process plan. This method traces from the proposed components or planned operations only the dimensions and tolerances that affect the given requirement, and therefore the equations for design or for manufacture can be established simultaneously and accurately. Hence it is possible to establish constraints for the optimisation of dimensions and tolerances for design or for manufacture.  相似文献   
999.
1000.
The brittle-ductile transition temperature in the solidification range depends on the composition of the phase which solidifies as the last one. The paper presents a thermochemical study of Fe-Mn-C-P system, determining the conditions of crystallisation of carbides, phosphides and the pseudo-ternary eutectic ML-M3C-M3P. Manganese raises the phosphorus concentration in eutectic. The eutectic temperature attains its maximum at about 6% of Mn. Then the brittle-ductile transition temperature is about 30 K higher than in ternary Fe-C-P alloy. A further raise is possible when the alloy is modified by an element forming stable, solide carbide, for ex. titanium. The results of theoretical analysis were verified by experimental work. The influence of titanium on the inclusions appearing in the vicinity of hot cracks of Hadfield cast steel has been studied.  相似文献   
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