发光层厚度对红光磷光聚芴电致发光性能的影响

文章采用喹啉氮杂环类锒配合物[（PPQ）2Ir（acac）]为客体,以聚芴和2-（4-二苯基）-5-（4-叔丁基苯基）-1,3,4-噁二唑（PBD）为主体,研究了不同发光层厚度对有机电致发光器件性能的影响．随着发光层厚度的增加,相同电压下器件的电流密度和发光亮度逐步减小,表现出明显的电荷捕获机制．当厚度达到70nm时,得到了发光亮度为1792cd／m^2,发光效率为6．16cd／A的高性能红光器件．     

Adjusting athletes' body mass index to better reflect adiposity in epidemiological research

Abstract

The aim of the present study was to identify when body mass index (BMI) is unlikely to be a valid measure of adiposity in athletic populations and to propose a simple adjustment that will allow the BMI of athletes to reflect the adiposity normally associated with non-athletic populations. Using data from three previously published studies containing 236 athletes from seven sports and 293 age-matched controls, the association between adiposity (sum of 4 skinfold thicknesses, in millimetres) and BMI was explored using correlation, linear regression, and analysis of covariance (ANCOVA). As anticipated, there were strong positive correlations (r = 0.83 for both men and women) and slope parameters between adiposity and BMI in age-matched controls from Study 1 (all P < 0.001). The standard of sport participation reduced these associations. Of the correlations and linear-regression slope parameters between adiposity and BMI in the sports from Studies 2 and 3, although still positive in most groups, less than half of the correlations and slope parameters were statistically significant. When data from the three studies were combined, the ANCOVA identified that the BMI slope parameter of controls (5.81 mm · (kg · m^?2)^?1) was greater than the BMI slope parameter for sports (2.62 mm · (kg · m^?2)^?1) and middle-distance runners (0.94 mm · (kg · m^?2)^?1) (P < 0.001). Based on these contrasting associations, we calculated how the BMI of athletes can be adjusted to reflect the same adiposity associated with age-matched controls. This simple adjustment allows the BMI of athletes and non-athletes to be used with greater confidence when investigating the effect of BMI as a risk factor in epidemiological research.     

Moderate Association of Anthropometry,But Not Training Volume,With Race Performance in Male Ultraendurance Cyclists

In 28 male Caucasian nonprofessional ultracyclists, we investigated whether anthropometry or training volume had an influence on race speed in the 600 km at the Swiss Cycling Marathon 2007. Anthropometric parameters (age, body mass, body height, skin-fold thicknesses) were determined before the race to calculate body mass index and percent body fat. In addition, participants, using a training diary, recorded their training volume in hours and kilometers in the 3 months before the race. The influence of anthropometry and training volume on speed in the race as the dependent variable was investigated in a multiple linear regression model. Anthropometry showed a moderate association with speed in the race (r² = .178, p < .05), whereas training volume showed no association (r² = .000, p > .05). We concluded that anthropometry had a greater influence on race performance than training volume in recreational ultraendurance cyclists.     

Equivalent thickness of materials of fused silica and stainless steel in the flow of microtubes

The deviation of flow characteristics from the predictions of the conventional theory for microtubes was attributed to the change of fluid viscosity resulted from the interactions between the molecules on solid wall and in fluid. The degree of this departure is dependent on the microtubes materials. A concept of equivalent thickness with which conventional theory can be used to predict the flow in microtubes without modifying the fluid viscosity was put forward. The values of equivalent thickness for fused silica and stainless steel materials were determined as 1.8 μm and 1.5 μm, respectively, by repeated numerical simulation.     

软土场地与静压预制桩的压桩力控制

论述静压预制桩压桩力对地表土层和下卧软土层承载能力的要求。在建立两者之间关系时，考虑压入土中桩的挤土效应对软土结构的破坏和因此引起的承载能力的降低。提供了不同型号压桩机在不同表土层厚度条件下，对含水量不同的软土层的许用压桩力的粗略定量解答。     

小型推力关节轴承轴圈外球面电解测厚工装设计

针对推力关节轴承内圈外球面镀铬层厚度检测采用电解法,在检测过程中经常因为难以固定工件、电解液的渗漏等因素导致难以测量测量不准确。本文设计专用工装,快速固定工件,准确地测量了镀层厚度。     

非酒精性脂肪性肝病和内脏脂肪厚度相关性研究

目的：评价超声测量内脏脂肪厚度对非酒精性脂肪性肝病（NAFLD）的诊断和分级的价值。方法：收集2010年8月至2011年4月在某院体检中心进行健康体检资料共122例,NAFLD组74例,非NAFLD组48例,经超声测量内脏脂肪厚度。结果：超声测量内脏脂肪厚度在NAFLD组和非NAFLD组之间差异有显著性统计学意义（P=0．004）。轻度、中度、重度NAFLD组测量的内脏脂肪厚度经方差分析结果为差异有统计学意义（F=9．91,P〈0．001）,进一步用LSD法分析显示两两之间都有差异。经超声测量的VFT诊断NAFLD的ROC曲线下面积为0．794,p=0．011,诊断切点值为2．70cm。结论：经超声测量的内脏脂肪厚度可作为NAFLD诊断和分级的指标。     

Correlation between serum lipid profile and carotid intima-media thickness in Polycystic Ovarian Syndrome

Abnormal lipid profile is often found in women with Polycystic Ovary Syndrome. To assess the impact of abnormal lipid profile on atherosclerosis in young Polycystic Ovary Syndrome women, carotid intima-media thickness as judged by B-mode ultrasonography were done in 30 young (18–35 yrs) Polycystic Ovary Syndrome women and in similarly age-matched 30 apparently healthy controls. Compared to controls, young Polycystic Ovary Syndrome women had significantly elevated serum total cholesterol, triglyceride and LDL-C levels and carotid intima-media thickness. HDL-C level did not differ significantly between two groups of women. In Polycystic Ovary Syndrome women carotid intima-media thickness was positively correlated with serum total cholesterol, triglyceride and LDL-C and negatively correlated with serum HDL-C. Our study suggests that even young Polycystic Ovary Syndrome women are prone to atherosclerosis from early age.     

地浸采铀中有效厚度的计算

有效厚度是地浸采铀中的一个重要参数,其精确度直接影响液固比和吨矿石酸耗等参数的精确度·有效厚度受矿层及围岩渗透系数、抽注液孔间距等因素影响·有效厚度一般可根据经验公式推算,但其精度较低·介绍一种有效厚度的精确计算方法·     

关于复合探测器的塑料闪烁体厚度及其对γ探测效率的研究

概述了带电粒子及γ射线的探测原理。对用于总β测量的复合探测器的塑料闪烁体厚度及其对γ的探测效率进行了理论计算。并用MATLAB得出其对γ探测效率的数值积分值。