Formation of nano-sized M2C carbides in Si-free GH3535 alloy.

GH3535 alloy is one of the most promising structural materials for molten salt reactors (MSRs). Its microstructure is characterized by equiaxed grains and coarser primary M6C carbide strings. In this study, stable nano-sized M2C carbides were obtained in GH3535 alloy by the removal of Si and thermal exposure at 650 °C. Nano-sized M2C carbide particles precipitate preferentially at grain boundaries during the initial stage of thermal exposure and then spread all over the grain interior in two forms, namely, arrays along the {1 1 1} planes and randomly distributed particles. The precipitate-free zones (PFZs) and the precipitate-enriched zones (PEZs) of the M2C carbides were found to coexist in the vicinity of the grain boundaries. All M2C carbides possess one certain orientation relationship (OR) with the matrix. Based on microstructural characterizations, the formation process of M2C carbides with different morphologies was discussed. The results suggested that the more-stable morphology and OR of M2C carbides in the Si-free alloy provide higher hardness and better post-irradiation properties, as reported previously. Our results indicate the preferential application of Si-free GH3535 alloy for the low-temperature components in MSRs.

Influence of NADH Concetration in the AST Reagent on Assay Performance / 现代检验医学杂志

Objective To estimate the assay performance of two different kind of reagent with different concentration of NADH.Methods Verificated function index of these two reagents,such as accuracy,sensitiveness,blank space and so on, and determined the molar extinction coefficient of NADH using hexokinase method and calculated the NADH density in two kind of AST reagents.Then estimated the effect of concentation of NADH on the analysis performance.Results NADH concentration was 0.21 mmol/L,and the sample detection limit of the linear was 1 629 U/L.NADH concentration was 0.13 mmol/L,and the sample detection limit of the linear was 1 263 U/L.So the gap between the two reagent’s detection linear was visible.But there were no significant changes in other performance indicators such as detection sensitivity,reagent blank,precision.Conclusion The NADH concentration in the reagent of AST had greatimpact on the detecting linear range, so should pay attention to the potential change of linear range in the daily work.

A clinical analysis of morning blood pressure surge in middle and old aged male hypertensive patients / 中华内科杂志

ObjectiveTo investigate the morning blood pressure surge(MBPS) and its relationship with 24-hour blood pressure variability and anti-hypertensive drugs in middle-aged and elderly hypertensive patients.Methods A total of 521 middle-age and elderly men were surveyed with ambulatory blood pressure monitoring and ambulatory electrocardiograms recordings as well as questionnaire investigation from January 2009 to December 2010.Subjects were divided into MBPS positive group and MBPS negative group according to the level of MBPS[ ＞35 mm Hg (1 mm Hg=0.133 kPa) or ≤35 mm Hg].ResultsIn all the cases,the prevalence of MBPS was 19.4％,of which the elderly and very elderly had higher prevalences ( 18.9％ and 21.8％,respectively) than the middle-aged (5.6％,both P ＜0.01 ).Significant differences could be found in age [ ( 81.6 ± 6.4 ) years vs ( 78.7 ± 9.7 ) years ],day mean systolic blood pressure [ ( 132.8 ± 13.3) mm Hg vs ( 128.8 ±13.3) mm Hg],fasting blood glucose [ (5.96 ± 1.59) mmol/L vs (5.68 ± 1.22) mmol/L] and 24-hour blood pressure variability between the two groups ( all P ＜ 0.05 ).Significant difference could be observed in the prevalence of MBPS between the diuretics-taking group and non-taking group (27.4％ vs 17.6％,P ＜0.05 ).ConclusionsThe elderly hypertensive patients are prone to appear MBPS phenomenon.Fasting blood glucose level,24-hour blood pressure variability may be associated with MBPS.Diuretic antihypertensive treatment may not be conductive for MBPS control.