摘要:This paper is concerned with oscillation of / - order neutral difference equationtwo sufficient conditions are obtained for oscillation of equation(*) with cn≥0 and cn≤0, sufficient and necessary conditions is obtained for oscillation of bounded solution of equation (*) with cn≡1.
摘要:In this paper, rings over which all R - projective modules are projective (RP -ring) are discussed, some equivalent conditions are obtained. It’s proved that S= Rn is RP- ringiff R is RP - ring; ∑n i=1 Ri is RP - ring iff every Ri is RP - ring. Finally, the left projective dimensionof RP - ring is discussed.
摘要:Based on the experiment investigation on W18Cr4V tool cutting with magnetic field, cutting principles and basic laws of HSS tool were discussed in this paper. It follows from the research that metal cutting with magnetic field can make cutting force shrinking, tool life longer, productivity higher and cost lower, machining quality improved obviously.
关键词:Cutting with magnetic field;Magneted tool;Cutting force;Tool life
摘要:The photosynthetic model compounds can be divided into three parts, they are dyads, compounds more than two segments and non-covalently linked supramolecular systems. They possess part of the properties of natural photosynthesis centers. It is expected that the study of photophysical and chemical properties of model compounds in superamolecular systems and solid states will be the most active field.
关键词:Photosynthesis;Model Compounds;Photoinduced electron transfer
摘要:The application of method of modellization of system theory in organic chemistry was introduced in this article, and the application of method of idea modellization and its effect were discussed and illustrated by examples , too. Therefore it was proved that the application of method of modellization in teaching was scientific in theory and was feasible and useful in practice.
摘要:The effect of the temperature and the nitrating agent on the nitration of oxidated asphalt was investigated. The temperature suitable for the nitration with mixed acid was determined. The property of the nitrated oxidated asphalt and its application in metal antirust was also studied.
摘要:This paper pointed out the method to describe CAPP input information by CHIM (Classified Herarchical Information Modelling)on the windows95 environment.