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991.
铜管内部阴极保护电位分布公式探讨 总被引:1,自引:0,他引:1
简述了管道内部阴极保护时电位分布公式的推导过程,重点推导和分析了双点阳极时其电位公式,并与文献中的同类公式进行了比较,同时,用该公式检验了试验结果。 相似文献
992.
993.
Due to the growing importance of width control in strip and plate mills, edge rolling is currently an im-portant process in
hot rolling mills. Research in edge rolling has been carried out, and in the present ar-ticle, models for roll force, torque,
and lever arm coefficient are derived using the upper bound method. A simple, kinematically admissible deformation zone and
velocity field, independent of friction in the roll gap, is proposed, and the energy dissipation rate is derived. The formula
for energy dissipation rate has, in practice, no limitation because all edge rolling geometries are safely in the area where
the formula is valid. Roll force and torque are derived by means of two independent integrals. Thus, the lever arm coef-ficient
is evaluated from the expressions for roll force and torque using conventional rolling theory. Roll-ing trials report good
agreement with theory. Measured roll forces are similar to calculated forces. Furthermore, the shape of the dogbone that arises
during edge rolling is in fairly good agreement with the calculated dogbone shape. Deviations are due to the deviation from
ideally plastic material in the ex-periments. Also, the strain distribution over the dogbone is similar to the proposed deformation
zone. Thus, a new formula has been developed to a stage that it can be implemented in width control systems for edge rolling
stands in hot strip and plate mills. 相似文献
994.
翁永基 《腐蚀科学与防护技术》2002,14(5):249-252
以塔里木和大港油田区域土壤腐蚀试验数据为例,论 证了区域腐蚀试验数据整体概率分布符合正态随机函数、其极大值数据符合Gumbel极值函数 .根据分布参数可以计算区内不同腐蚀性土壤比例、可能存在最大土壤腐蚀性和出现的概率 等工程信息. 相似文献
995.
996.
S.?H.?Yu H.?S.?Ryoo S.?K.?HwangEmail author D.?H.?Shin 《Metals and Materials International》2003,9(2):107-114
Grain boundary character distribution in equal-channel-angular pressed Zr was studied. Using a die design of 90°/20° and an
operation temperature of 350°C. The initial grain size of 20 μm was reduced to about 270 nm with 4 passes via route Bc. The grain growth kinetics of the recrystallized state was obtained by experiment and Monte-Carlo computer simulation, respectively,
which showed good agreement. Based on kinetics and morphological characteristics, it was concluded that the grain coarsening
mechanism was governed by normal grain growth. No sign of abnormal grain growth was detected either in the experiment or in
simulation despite taking into consideration anisotropy in grain boundary energy as well as its mobility. This indicates that
grain boundaries produced by severely deformed Zr are stable against explosive coarsening. The evolution characteristics of
the microstructure in the present ECA pressed and recrystallized Zr differed from those of cold rolled Ti in that the grain
boundary misorientation distribution and texture were rather stable during grain growth.
Jointly Appointed by the Center for Advanced Aerospace Materials
This article is based on a presentation made in the 2002 Korea-US symposium on the “Phase Transformations of Nano-Materials,”
organized as a special program of the 2002 Annual Meeting of the Korean Institute of Metals and Materials, held at Yonsei
University, Seoul, Korea on October 25–26, 2002. 相似文献
998.
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