摘要:A new method controlling the speed of a motor by using the rotor frequency of a wound-rotor asynchronous motor is introduced. The structure and the working principle of this new controller are expounded, and also the wave shape of principle are presented. This controller is a static device of electricity and can be used in stead of the common tacho-generator,and it will be of great practical values.
摘要:The purpose of this paper is to establish the universal mathematical model for helicoids employed in mechanical engineering, and than to set up their universal vector equation (2) and make use of it to analyse some common helicoids, such as cylindrical helicoid, conical helicoid, plane thread surface, etc.
摘要:The purpose of this paper is mainly to introduce the correct calculating model and machining method for cutting the cylindrical surface on the motorcycle brake shoe so as to make the brake shoe contact completely with the brake hub on-position, and make the braking efficiency up to or over the requirement of Chinese Standard GB5382-85.
摘要:In this paper, we describe the production of a waterproof paint, which can substitute for PVA, by using corn starch as material and the research on the preparation principle, formula’s design, technical condition, product property and the crux affecting the quality. The main merits of this paint are low cost and good waterproof property.
摘要:The copper (Ⅱ)-catalyzed polymerization of 2,4,6-tribromophenol was studied using different copper(Ⅱ)catalysts. Using Taft substituent constant as parameter, copper(Ⅱ) salt has catalytic activity as ∑δ*>5.5. The reactions with copper(Ⅱ) complexes isolated show that the copper (Ⅱ) complex prepared at a mole ratio of copper (Ⅱ) chloride/sodium methoxide equals 0.5 has maximum activity. Single electron transfer reaction mechanism was proposed for the copper (Ⅱ)-catalyzed polymerization through the copper (Ⅱ)-phenoxo complex intermediate.
摘要:Atomic aboerption spectro-photometer was used to determine the Chromium in human’s hair with a new digestion method in which the human’s hair was digested with 1:1 HNO3 in a high pressure digestion pot. With this new method a good result was obtained, a better collection ratio of chromium within 96%-107% was got and the reagent can be saved.
关键词:Analysis of Chromium;High pressure digestion pot;Atomic absorption spectrophotometry
摘要:Littlewood-Paley operators, g-function, s-function and gλ*-function(λ > 3), consided as operators on the space of weighted campanato ewap, are "bounded operators
摘要:Let G be a 2-connected graph of order n with vertices v1 ,v2,…,vn, satisfying where di = d(vi) for all (?). This paper establishes the following sufficient condition guaranting the circumference of G
摘要:In this paper we simply analyse the internal relations of eight theorems on theory of real numbers, and show clearly the characteristics of the mathematical method they provided.
关键词:theory of real numbers;properties of complete;properties of nature
摘要:The energy variance of a static electric field when a dielectric of finite volume is presented under conditions of constant field source or boundary potential unchanged is discussed. The expressions of the polarization energy of the dielectric in both conditions is deduced and the difference of the physical meaning of this two expressions is pointed out.
关键词:static electric field energy;polarization energy;polarization energy density