5 research outputs found
Effect of water temperature in the deep sea on the mitigation of hydrogen embrittlement by O2 impurity
No full textThe addition of trace amounts of oxygen (O2) to hydrogen gas (H2) can mitigate hydrogen embrittlement (HE) in steels by suppressing the hydrogen uptake. In this study, the influence of temperature on the HE mitigation effect of O2 was investigated using fracture toughness tests of SCM440 low-alloy steel in H2 environments containing volume ppm-levels of O2 at 293 K and 277 K. Lowering the temperature from 293 K to 277 K enhanced the HE in pure H2. However, the addition of O2 to the H2 effectively mitigated the HE, with the mitigation effect becoming more pronounced at lower temperatures. This temperature-dependent mitigation is attributed to the different adsorption behaviors of H2 and O2 on the iron surface. O2 adsorption onto iron occurs without an activation barrier, making it essentially temperature-independent. In contrast, H2 adsorption requires overcoming an activation barrier and thus decreases with a lower temperature. Consequently, decreasing the temperature selectively suppresses H2 adsorption while leaving O2 adsorption unaffected, thus enhancing the relative effect of O2. Furthermore, the presence of O2 increases the activation barrier for H2 adsorption, which amplifies the temperature dependence of the H2 adsorption. These dual effects contribute to the enhanced HE mitigation by O2 at lower temperatures.journal articl
Distribution of melon and Arabidopsis unigenes according to the Gene Ontology scheme for functional classification of gene products
No full text<p><b>Copyright information:</b></p><p>Taken from "MELOGEN: an EST database for melon functional genomics"</p><p>http://www.biomedcentral.com/1471-2164/8/306</p><p>BMC Genomics 2007;8():306-306.</p><p>Published online 3 Sep 2007</p><p>PMCID:PMC2034596.</p><p></p
