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Effect of weld microstructure on brittle fracture initiation in the thermally-aged boiling water reactor pressure vessel head weld metal
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Noora Hytönen Zai-qing Que Pentti Arffman Jari Lydman Pekka Nevasmaa Ulla Ehrnstén Pål Efsing 《矿物冶金与材料学报》2021,28(5):867-876
Effects of the weld microstructure and inclusions on brittle fracture initiation are investigated in a thermally aged ferritic high-nickel weld of a reactor pressure vessel head from a decommissioned nuclear power plant.As-welded and reheated regions mainly consist of acicular and polygonal ferrite,respectively.Fractographic examination of Charpy V-notch impact toughness specimens reveals large inclusions(0.5-2.5μm)at the brittle fracture primary initiation sites.High impact energies were measured for the specimens in which brittle fracture was initiated from a small inclusion or an inclusion away from the V-notch.The density,geometry,and chemical composition of the primary initiation inclusions were investigated.A brittle fracture crack initiates as a microcrack either within the multiphase oxide inclusions or from the debonded interfaces between the uncracked inclusions and weld metal matrix.Primary fracture sites can be determined in all the specimens tested in the lower part of the transition curve at and below the 41-J reference impact toughness energy but not above the mentioned value because of the changes in the fracture mechanism and resulting changes in the fracture appearance. 相似文献
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Manning AK Hivert MF Scott RA Grimsby JL Bouatia-Naji N Chen H Rybin D Liu CT Bielak LF Prokopenko I Amin N Barnes D Cadby G Hottenga JJ Ingelsson E Jackson AU Johnson T Kanoni S Ladenvall C Lagou V Lahti J Lecoeur C Liu Y Martinez-Larrad MT Montasser ME Navarro P Perry JR Rasmussen-Torvik LJ Salo P Sattar N Shungin D Strawbridge RJ Tanaka T van Duijn CM An P de Andrade M Andrews JS Aspelund T Atalay M Aulchenko Y Balkau B Bandinelli S Beckmann JS Beilby JP Bellis C Bergman RN Blangero J 《Nature genetics》2012,44(6):659-669
Recent genome-wide association studies have described many loci implicated in type 2 diabetes (T2D) pathophysiology and β-cell dysfunction but have contributed little to the understanding of the genetic basis of insulin resistance. We hypothesized that genes implicated in insulin resistance pathways might be uncovered by accounting for differences in body mass index (BMI) and potential interactions between BMI and genetic variants. We applied a joint meta-analysis approach to test associations with fasting insulin and glucose on a genome-wide scale. We present six previously unknown loci associated with fasting insulin at P < 5 × 10(-8) in combined discovery and follow-up analyses of 52 studies comprising up to 96,496 non-diabetic individuals. Risk variants were associated with higher triglyceride and lower high-density lipoprotein (HDL) cholesterol levels, suggesting a role for these loci in insulin resistance pathways. The discovery of these loci will aid further characterization of the role of insulin resistance in T2D pathophysiology. 相似文献
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Taal HR St Pourcain B Thiering E Das S Mook-Kanamori DO Warrington NM Kaakinen M Kreiner-Møller E Bradfield JP Freathy RM Geller F Guxens M Cousminer DL Kerkhof M Timpson NJ Ikram MA Beilin LJ Bønnelykke K Buxton JL Charoen P Chawes BL Eriksson J Evans DM Hofman A Kemp JP Kim CE Klopp N Lahti J Lye SJ McMahon G Mentch FD Müller-Nurasyid M O'Reilly PF Prokopenko I Rivadeneira F Steegers EA Sunyer J Tiesler C Yaghootkar H;Cohorts for Heart Aging Research in Genetic Epidemiology Consortium 《Nature genetics》2012,44(5):532-538
To identify genetic variants associated with head circumference in infancy, we performed a meta-analysis of seven genome-wide association studies (GWAS) (N = 10,768 individuals of European ancestry enrolled in pregnancy and/or birth cohorts) and followed up three lead signals in six replication studies (combined N = 19,089). rs7980687 on chromosome 12q24 (P = 8.1 × 10(-9)) and rs1042725 on chromosome 12q15 (P = 2.8 × 10(-10)) were robustly associated with head circumference in infancy. Although these loci have previously been associated with adult height, their effects on infant head circumference were largely independent of height (P = 3.8 × 10(-7) for rs7980687 and P = 1.3 × 10(-7) for rs1042725 after adjustment for infant height). A third signal, rs11655470 on chromosome 17q21, showed suggestive evidence of association with head circumference (P = 3.9 × 10(-6)). SNPs correlated to the 17q21 signal have shown genome-wide association with adult intracranial volume, Parkinson's disease and other neurodegenerative diseases, indicating that a common genetic variant in this region might link early brain growth with neurological disease in later life. 相似文献
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Jari Hännikäinen 《Journal of forecasting》2018,37(1):102-118
This paper analyzes the relative performance of multi‐step AR forecasting methods in the presence of breaks and data revisions. Our Monte Carlo simulations indicate that the type and timing of the break affect the relative accuracy of the methods. The iterated autoregressive method typically produces more accurate point and density forecasts than the alternative multi‐step AR methods in unstable environments, especially if the parameters are subject to small breaks. This result holds regardless of whether data revisions add news or reduce noise. Empirical analysis of real‐time US output and inflation series shows that the alternative multi‐step methods only episodically improve upon the iterated method. 相似文献
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