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 The contents of this paper are as follows: (1) The local vacuum range above the molybdenum melting pool during the process of eletronbeam welding and the effect of technological factors on it are investigated. The authors give a thermodynamic analysis of the metallurgical reactions, possibly ocouring during the welding process. (2) The effects of welding technology on the properties, particularly on the ductility of molybdenum welds are studied. (3) In the last part of the paper, the authors made a... The contents of this paper are as follows: (1) The local vacuum range above the molybdenum melting pool during the process of eletronbeam welding and the effect of technological factors on it are investigated. The authors give a thermodynamic analysis of the metallurgical reactions, possibly ocouring during the welding process. (2) The effects of welding technology on the properties, particularly on the ductility of molybdenum welds are studied. (3) In the last part of the paper, the authors made a study of the influence of welding technology on the grainsize of bead metal, impurity contents on the grain boundaries, and the ductility of the crystals of bead metal, and thus, an analysis of the cause of brittleness of molybdenum welds. On the basis of the foregeing results, the authors suggest a satisfactery technology for welding molybdenum (thickness 1. 5 mm) with eloctronbeam welding set ZD30 and point out the direction for farther improvement of the ductility of welds.  本文包括如下内容： （１）研究了电子束焊钼时，熔池区域局部真空度及焊接工艺对局都真空度的影响。对焊接寸可能进行的冶金反应进行了热力学分析。 （２）研究了焊接工艺对接头性能，特别是接头塑性的影响。 （３）研究了焊接工艺对焊缝晶粒度、晶界杂质及晶体塑性的影响，并对钼焊接接头的脆化原因进行了分析。 在上述研究结果的基础上，作者提出以ＺＤ－３０屯子束焊机焊接厚度为１．５毫米钼板的合适的工艺规范，并提出了改进钼接头塑性的方向。  If one deals with a practical system, arising out of physics or technology, it is quite certain that perturbations will come up which are expressed not only in terms of initial conditions other than x=0 but also, and above all, in terms of the exterior and adventitious actions, for example fairly brusque impulses, etc, This problem is termed by G. N, Dubosin as that "stability in the case of constantly acting disturbances"[2]or"stability under persistent disturbance". Simple sufficient conditions for... If one deals with a practical system, arising out of physics or technology, it is quite certain that perturbations will come up which are expressed not only in terms of initial conditions other than x=0 but also, and above all, in terms of the exterior and adventitious actions, for example fairly brusque impulses, etc, This problem is termed by G. N, Dubosin as that "stability in the case of constantly acting disturbances"[2]or"stability under persistent disturbance". Simple sufficient conditions for such stability have been obtained by I. G. Malkin[3].In this paper, we consider the necessity of Malkin's conditions in quite general case and prove that for the particular case of two dimensional autonomous systems, assumed analytic, the malkini's conditions are necessary.The author finds that Theorem Ⅳ in Malkin's article is erroneous. Thus, many counter examples are constructed for showing that the stability under persistent disturbance may happen in a system which is stable but not asymptotically stable in the sense of Liapunov.The principal result may be extended to ndimensional autonomous systems. Further, criterion for unstability under persistent disturbance is given.  本文就关于在经常作用的外援下稳定性的充分条件讨论其必要性,证明对二阶解析系统这条件是充要的,并把主要结果推广到高阶的情形,还举出非解析系统该条件不是必要的反例,最后给出一个经常作用的外援下不稳定性的准则.  Theoretical coke rate means the necessary amount of coke to satisfy the thermal and chemical requirements under given conditions of raw materials, blast temperature, etc. The newly proposed method is characterized by combination of material and heat balance into one equation, and by that, the only thermal income is the heat of combustion before the tuyere with subtraction of heat carried away by the hot top gas. With this thermal balance, the necessary tuyere carbon is found. By adding to this carbon the solution... Theoretical coke rate means the necessary amount of coke to satisfy the thermal and chemical requirements under given conditions of raw materials, blast temperature, etc. The newly proposed method is characterized by combination of material and heat balance into one equation, and by that, the only thermal income is the heat of combustion before the tuyere with subtraction of heat carried away by the hot top gas. With this thermal balance, the necessary tuyere carbon is found. By adding to this carbon the solution carbon in pig iron and direct reduction carbon, the total carbon is finally obtained.By partial differentiation, a convenient and practically accurate method is derived for calculating effects of different factors on coke rate. Calculations for some Chinese and Japanese blast furnaces are given to show how this method might be used to examine operational efficiency, to calculate effects on coke rate of new technology like fuel injections through tuyere, and used for design purposes. Comparisons of this method with others like that of Runm and Pavlov are briefly given.  理論焦比是指在一定原料和风溫条件下渗碳、发热和还原所需的焦炭;現有各种計算方法的缺点;以风口热函減去炉頂煤气热函作为唯一热量收入的热平衡計算方法,以物料平衡和热平衡結合为基础,利用偏微分找出的計算各种因素对焦比影响的方法。   << 更多相关文摘 
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