The equation of phase equilibria in nano-sized crystal of metals has been established in terms of thermodynamic equilibrium. The thermodynamic parameters are calculated and the critical grain size for the stable high-temperature phase at room temperature is obtained. As an example, the critical grain size of β-Co at room temperature is determined at 35nm when the excess volume is 10%. The result agrees well with the experiment of Katakimi et al. The factors affecting the stability of β-Co are also discussed.
{"title":"The structural stability in nano-sized crystals of metals","authors":"Q. Meng, Y. Rong, T. Hsu","doi":"10.1360/02YE9056","DOIUrl":"https://doi.org/10.1360/02YE9056","url":null,"abstract":"The equation of phase equilibria in nano-sized crystal of metals has been established in terms of thermodynamic equilibrium. The thermodynamic parameters are calculated and the critical grain size for the stable high-temperature phase at room temperature is obtained. As an example, the critical grain size of β-Co at room temperature is determined at 35nm when the excess volume is 10%. The result agrees well with the experiment of Katakimi et al. The factors affecting the stability of β-Co are also discussed.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127125829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xunliang Liu, W. Tao, P. Zheng, Ya-Ling He, Qiuwan Wang
A fuzzy control method was used to accelerate iteration convergence in numerical fluid dynamic simulation using SIMPLER algorithm. The residual ratio of momentum or energy equation between two successive iterations was used as the input variable. A fuzzy logic algorithm was developed in order to obtain the relative increment of the under-relaxation factor and its new value was then used for the next iteration. The algorithm was tested by four benchmark problems. In all cases considered, when the fuzzy control logic was used, convergence was achieved with nearly the minimum number of iterations, showing the feasibility of the proposed method.
{"title":"Control of convergence in a computational fluid dynamic simulation using fuzzy logic","authors":"Xunliang Liu, W. Tao, P. Zheng, Ya-Ling He, Qiuwan Wang","doi":"10.1360/02YE9057","DOIUrl":"https://doi.org/10.1360/02YE9057","url":null,"abstract":"A fuzzy control method was used to accelerate iteration convergence in numerical fluid dynamic simulation using SIMPLER algorithm. The residual ratio of momentum or energy equation between two successive iterations was used as the input variable. A fuzzy logic algorithm was developed in order to obtain the relative increment of the under-relaxation factor and its new value was then used for the next iteration. The algorithm was tested by four benchmark problems. In all cases considered, when the fuzzy control logic was used, convergence was achieved with nearly the minimum number of iterations, showing the feasibility of the proposed method.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127606287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weidong Huang, Xin Lin, Meng Wang, Shujuan Shen, Yunpeng Su, Zhenxia Liu
Based on the growth competition between different pattern and phases, the pattern and phase selection during peritectic solidification is analysed by applying the maximum interface temperature criterion to the interface response functions calculated from a numerical model for single phase solidification. The theoretical results agree very well with the experimental results published in literature.
{"title":"Pattern and phase selection of peritectic reaction during directional solidification","authors":"Weidong Huang, Xin Lin, Meng Wang, Shujuan Shen, Yunpeng Su, Zhenxia Liu","doi":"10.1360/02YE9053","DOIUrl":"https://doi.org/10.1360/02YE9053","url":null,"abstract":"Based on the growth competition between different pattern and phases, the pattern and phase selection during peritectic solidification is analysed by applying the maximum interface temperature criterion to the interface response functions calculated from a numerical model for single phase solidification. The theoretical results agree very well with the experimental results published in literature.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125977532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We give definitions on increasing, constant and decreasing returns to scale under the generalized data envelopment analysis (GDEA) model. The GDEA model prossesses cone structures for describing evaluators’ preferences toward different decision making units (DMU) and toward different input / output categories. The GDEA model contains many important DEA models as its subclasses. Based upon the definition, we discuss and rigorously prove the necessary and sufficient conditions for a DMU to have increasing, constant and decreasing returns to scale under a GDEA model, and discuss and clarify the differences and relationships of these conditions under different subclasses of the GDEA model. Furthermore, we describe a method based on a two-stage linear program to test returns to scale properties.
{"title":"The necessary and sufficient conditions for returns to scale properties in generalized data envelopment analysis model","authors":"Q. Wei, Gang Yu, Jianshou Lu","doi":"10.1360/02ye9058","DOIUrl":"https://doi.org/10.1360/02ye9058","url":null,"abstract":"We give definitions on increasing, constant and decreasing returns to scale under the generalized data envelopment analysis (GDEA) model. The GDEA model prossesses cone structures for describing evaluators’ preferences toward different decision making units (DMU) and toward different input / output categories. The GDEA model contains many important DEA models as its subclasses. Based upon the definition, we discuss and rigorously prove the necessary and sufficient conditions for a DMU to have increasing, constant and decreasing returns to scale under a GDEA model, and discuss and clarify the differences and relationships of these conditions under different subclasses of the GDEA model. Furthermore, we describe a method based on a two-stage linear program to test returns to scale properties.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116462142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：