نتایج جستجو برای: cut 380a

تعداد نتایج: 73948  

ژورنال: :فصلنامه علمی - پژوهشی مواد نوین 2010
مصطفی کاراموز مسعود امامی محمد علیپور مرتضی آذربرمس

در این پژوهش تاثیر عنصر لیتیم بر ریز ساختار و ویژگی های مکانیکی آلیاژ آلومینیوم 380 a بررسی شده است. نشان داده شد هنگامی که لیتیم تا میزان 1/0درصد وزنی به آلیاژ پایه (al-8.5%si-3.5%cu-1%fe) اضافه می شود، ریخت شناسی سیلیسم یوتکتیک و فاز β-al5fesi از حالت صفحات تیغه ای و ضخیم پیوسته به حالت الیافی و ریز بهسازی می شوند. آلیاژ حاوی 06/0 درصد لیتیم استحکام و ازدیاد طول نسبی بالاتری دارد که به احتمال...

Journal: :Combinatorica 2007
Benny Sudakov

The well-known Max Cut problem asks for the largest bipartite subgraph of a graph G. This problem has been the subject of extensive research, both from the algorithmic perspective in computer science and the extremal perspective in combinatorics. Let n be the number of vertices and e be the number edges of G and let b(G) denote the size of the largest bipartite subgraph of G. The extremal part ...

Journal: :J. Algorithms 2000
Uriel Feige Marek Karpinski Michael Langberg

We analyze the addition of a simple local improvement step to various known ran-domized approximation algorithms. Let ' 0:87856 denote the best approximation ratio currently known for the Max Cut problem on general graphs GW95]. We consider a semideenite relaxation of the Max Cut problem, round it using the random hyperplane rounding technique of ((GW95]), and then add a local improvement step....

2011
Piotr Berman Marek Karpinski

This paper studies the existence of eecient (small size) ampliiers for proving explicit inaproximability results for bounded degree and bounded occurrence combinatorial optimization problems, and gives an explicit construction for such ampliiers. We use this construction to improve the currently best known approximation lower bounds for bounded occurrence instances of linear equations mod 2, an...

Journal: :J. Comput. Syst. Sci. 1998
Wenceslas Fernandez de la Vega Claire Mathieu

Metric MAX-CUT is the problem of dividing a set of points in metric space into two parts so as to maximize the sum of the distances between points belonging to distinct parts. We show that metric MAX-CUT has a polynomial time randomized approximation scheme.

Journal: :International Journal of Reproduction, Contraception, Obstetrics and Gynecology 2016

Journal: :journal of mining and environment 2014
hamid khoshdast

a new parametric model was developed for predicting cut point of hydraulic classifiers. the model directly uses operating parameters including pulp flowrate, feed particle size characteristics, pulp solids content, solid density and particles retention time in the classification chamber and also covers uncontrollable errors using calibration constants. the model applicability was first verified...

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