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991.
Jin Hong Kim Yoon Young Kim 《International journal for numerical methods in engineering》2000,49(5):653-668
This paper presents a new one‐dimensional theory for static and dynamic analysis of thin‐walled closed beams with general cross‐sections. Existing one‐dimensional approaches are useful only for beams with special cross‐sections. Coupled deformations of torsion, warping and distortion are considered in the present work and a new approach to determine sectional warping and distortion shapes is proposed. One‐dimensional C0 beam elements based on the present theory are employed for numerical analysis. The effectiveness of the present theory is demonstrated in the analysis of thin‐walled beams having pillar sections of automobiles and excavators. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
992.
S. U. Hong J. H. Jin J. Won Y. S. Kang 《Advanced materials (Deerfield Beach, Fla.)》2000,12(13):968-971
993.
The effect of oxide component content on the low melting point zone (LMP) in the CaO‐MgO‐Al2O3‐SiO2 system has been analysed using FactSage software. The contents of dissolved elements [Si], [Mg], [O] and [Al] in liquid steel in equilibrium with the LMP inclusions in the CaO‐MgO‐Al2O3‐SiO2 system have been calculated. The results show that the CaO‐MgO‐Al2O3‐SiO2 system has the largest LMP zone (below 1400°C) when the Al2O3 content is 20% or the MgO content is 10%. The LMP zone becomes wide with the increase in CaO content (within the range of 0~30 mass%) and the decrease in SiO2 (from 25 to 5 mass%). To obtain the LMP (below 1400°C) inclusions, the [Mg], [Al] and [O] contents must be controlled within the range of 0.2~2 ppm, 1.0~2.0 ppm and 60~100 ppm, respectively. 相似文献
994.
Lei Chen Hongyan Xue Xiaocong Ma Miao Jin Hongjun Long Tianqiao Mao Jianfeng Wang 《国际钢铁研究》2015,86(12):1583-1593
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998.
Prostate development and disease are androgen dependent. However, the nature of hormonal effects on the prostate of healthy young men is not clear. We, therefore, measured prostate size in males chronically exposed to high doses of androgens (AS; habitual anabolic steroid abusers; n = 15) or estrogens (E; male to female transsexuals; n = 11) and compared the results with those in age-matched healthy eugonadal men without known prostate disorders. Prostate size was measured by planimetric ultrasound as cross-sectional areas and maximal dimensions in three orthogonal dimensions with a 7.5-megahertz B-mode sector scanner biplane in a transrectal transducer at 2.5 mm steps from the base to the apex of prostate. Total prostate volume (TPV) was reconstructed from planimetric sections, central prostate volume (CPV) was calculated by the ellipsoidal formula from the appropriate three maximum dimensions, and peripheral prostate volume was determined by the difference between TPV and CPV. Compared with age-matched controls, TPV was normal (-2%) in AS (P = 0.752) and reduced by 31% in E (P = 0.002), whereas CPV was increased by 20% in AS (P = 0.002) and reduced by 46% in E (P = 0.002), and the ratio of CPV/peripheral prostate volume was increased by 77% in AS (P < 0.001) and decreased by 33% in E (P = 0.047). Blood sex hormone-binding globulin was elevated by nearly 500% in E (P < 0.001), but was reduced by 47% in AS (P = 0.003). Prostate-specific antigen was normal (-6%) in AS (P = 0.799) and decreased by 86% in E (P = 0.002). Prostatic acid phosphatase was increased by 26% in AS (P = 0.007), but was unchanged (-28%) in E (P = 0.106). Total and free testosterone levels were reduced to castrate levels in E, whereas LH, FSH, and total testosterone levels were significantly reduced in AS. We conclude that in the human prostate of young men, CPV is more hormonally sensitive than TPV, and during high dose treatment, CPV is preferentially increased by chronic androgen treatment and decreased by chronic estrogen treatment. The reduction of TPV by estrogens was less than expected if solely attributable to inhibition of endogenous gonadotropin and testosterone secretion, suggesting that estrogens also have a positive effect on the normal human prostate. The reversibility and long term significance of androgen-induced stimulation of CPV and, in particular, its relationship to the onset and severity of benign prostatic hyperplasia remain to be clarified. 相似文献
999.
Smooth bar creep rupture tests were conducted under constant loads at 1033 and 1144 K using RENé 80. Creep deformation occurred dominantly by the dislocation creep mechanism, but creep rupture proceeded by the continual nucleation and growth of cavities. Rupture times were well predicted by the constrained diffusive growth model of Riedel, particularly at low applied stresses, but their temperature dependence and the Monkman-Grant product were better related to the unconstrained diffusive growth models. Interruption tests showed development of micro- cracks in the tertiary stage of creep and sometimes revealed edge cracks, the growth of which provided the creep crack growth rate. 相似文献
1000.
质量成本是指企业为保证产品质量而支出的一切费用,以及产品质量未达到规定的标准而造成的一切损失的总和。开展质量成本研究工作是企业深化质量管理和成本管理的一条有效途径。 相似文献