نتایج جستجو برای: brinell hardness

تعداد نتایج: 26023  

Journal: :Journal of Computer and System Sciences 1994

2017
Farahnaz Sharafeddin Mahsa Kowkabi Soodabe Shoale

BACKGROUND Home bleaching agents may exert some negative effects on surface hardness of restorative materials such as glass-ionomer cements (GICs). Since some studies have shown that some components such as hydroxyapatite (HA), as a bioactive glass, can improve the mechanical properties of dental materials, the effect of bleaching agents on surface hardness of GICs containing hydroxyapatite is ...

Journal: :Scientific American 1908

Journal: :Scientific American 1881

2012
Tamás Gál

Finding a proper local measure of chemical hardness has been a long-standing aim of density functional theory. The traditional approach to defining a local hardness index, by the derivative of the chemical potential l with respect to the electron density nðr *Þ subject to the constraint of a fixed external potential vðr *Þ, has raised several questions, and its chemical applicability has proved...

Journal: :Journal of dental research 1958
R G CRAIG F A PEYTON

THE hardness of enamel and dentin has been determined by a variety of methods including abrasion," 2 pendulum,' scratch,4-7 and indentation" teehnics. Since the hardness of enamel and dentin has been shown to have considerable local variations, the methods using a microscratch or microindentation have been preferred. One of the more common types is the Knoop diamond indenter14 which has been us...

Journal: :Environmental toxicology and chemistry 2001
J Akkanen J V Kukkonen

The influence of water hardness and dissolved organic matter (DOM) on bioavailability of organic chemicals to Daphnia magna was studied by using benzo[a]pyrene (BaP), pyrene, atrazine, and 3,3',4,4'-tetrachlorobiphenyl (TCB) as model compounds. Two types of DOM were used, namely Lake Kontiolampi, Joensuu, Finland water (KL) and Nordic reference fulvic acid (NoFA) dissolved in artificial freshwa...

2013
Wenyi Yan Abbas Amini Qingping Sun

An experimental study on the indentation hardness of NiTi shape memory alloys (SMAs) by using a spherical indenter tip and a finite element investigation to understand the experimental results are presented in this paper. It is shown that the spherical indentation hardness of NiTi SMAs increases with the indentation depth. The finding is contrary to the recent study on the hardness of NiTi SMAs...

Journal: :Scientific American 1917

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