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991.
In this paper through the static loading tests of 6 inflexion zones and 2 cantilever zones in full-size constrained R/C beams, the stress performance in rebars cut-in-phases and subjected to negative moment is studied. The stress properties of extended length of rebars with different shear-span ratiosare analysed on basis of the full measurement of strain distributions combined with the investigation on state and regularity of the diagonal cracks development and series of new knowledge are obtained. It is found that current Concrete Design Code provisions on the extended length are inadequate for the high shear-span ratio and superfluous for the low shear-span ratio. The theoretical and experimental foundations are provided for determining proper value of extended length for rebars cut-in-phases. 相似文献
992.
Li Jianzhong Wang Guanjie 《保鲜与加工》1993,(2):14-18
By comparing the techniges of the production and the logic predicate for knowledge representation, this paper presents a kind of constructure of combinatorial knowledge base applied to the expert system for switch operation in electric power system . This constructure of knowledge base to be expanded and revised easily,and it is cinvenitnt to build the general shell of the expert system. 相似文献
993.
994.
Bai Shaoliang 《保鲜与加工》1989,(2)
This paper makes an analysis and comparison of the calculatingsystem for second-order effect in columns of reinforced concrete frames proposedby scholars at home and abroad,and the systems adopted by codes of manycountries.The focus is on explaining the conceptual error and deficiency in somemethods.After expounding the basic law of the second-order effect in framecolumns with different restraints,this paper suggests an improvement of thecalculating system for second-order effect in frame columns for China's DesignCode of Concrete Structures. 相似文献
995.
Li Maoqin Duan Yurong 《保鲜与加工》1989,(4):22-29
In this paper, a kind of grey linear programming with grey interval coefficients is discussed,the definitions of the first and second whitenized linear programmlngs and the grey dual linear programmings are presented, the relationships between the solutions of the above three kinds of programming and the solution of the primal programming are explored, and some new conclusions are obtained. 相似文献
996.
Li Yourong Jin Mingcong Tang Jingwen 《保鲜与加工》1993,(6):46-50
The concept of loss rate of available energy was introduced for evaluating heat exchanger performance. At the same time, the general expression of loss rate of available energy was obtained for heat exchangers of several typical. And NL criteria was recommended for evaluation of the loss rate of available energy of heat exchanger. Then. the influences of inlet temperatures ratio, heat capacity ratio of fluids, the number of heat transfer units and flow patterns of heat exchanger on ,VL criteria were also discussed. 相似文献
997.
Based on properties of parameters and test data of dom-estic steel,this paper analyses the reliability and partial coefficient forresistance of steel frame columns of tall builings.The result may serveas a scientific basis.It is not only for domestic steel instead of importedsteel in building tall steel structures,but also for compiling concerendstandards. 相似文献
998.
Li Runfang Li Yusheng 《保鲜与加工》1993,(1):96-101
A new finite element method is presented in this paper to analyze the thermo-
elastic contact problem with heat input on meshing tooth faces. The computational model of meshing gear has been established and the frictional heat input on meshing tooth faces is estimated. In addition, 2-D finite element analysis program for this kind of problem is listed. The test and practical examples are given to show the validity and versatility of this method. 相似文献
999.
1000.
Li Jianping Zhang Wanping Chen Tinghuai Shu Wenzhi 《保鲜与加工》1997,(2):63-68
Based on the optimal control theory and Lagrange interpolation an optimal design model of plane cascades of 3D blade in an arbitrary surface of revolution is established. Using wavelet theory to solve the model, and lots of numerical results are obtained. The results show that the wavelet method is more effective than the conventional methods. 相似文献