Lord's paradox: A generic problem.

As F. M. Lord (see 42:2) demonstrated, the use of analysis of covariance on nonexperimental data cannot be counted on to make proper allowances for uncontrolled preexisting differences between groups. It is suggested that this interpretational problem is not limited to nonexperimental research but is generic to the research process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

面向不对称察觉的低压配电网分相接线图自动成图

态势可视化是低压配电网现代化监管关键技术之一,为此提出配电变压器为中心低压配电网(TCDN)概念作为研究及工程应用的对象和目标。清晰美观的接线图自动生成是TCDN态势可视化的前提,接线不对称性和负荷不对称性是低压配电网的关键特点,因此提出2类适合态势感知的分相接线图布局设计。提出了TCDN分相接线图自动生成原理,基于该原理的接线图,既能确保三相四线主干线和三相用户的接线对称性,也能清晰识别出单相双线用户导致的接线不对称性。对于提出的虚拟全单相接线图形,基于其单线束扇形图形设计参数和排列顺序,提出了单线束初始布局以及缩放和旋转参数计算方法以生成初始图形,再进行基于力导的美化计算以得到较为美观的图形。基于提出的原理,得到的虚拟全单相接线图形可以分解组装得到分相接线图。案例验证了该方法的快速性和有效性,其电压态势时序图片可以很好地察觉含单相户用光伏、单相及三相负荷变化下的低压配电网动态运行特性。     

砖混再生粗骨料混凝土损伤本构关系EI北大核心CSCD

为了研究取代率和配合比设计方法对砖混再生粗骨料混凝土力学性能的影响,采用应变等价性原理并基于Weibull函数分布建立了砖混再生粗骨料混凝土损伤本构模型,并结合分布参数与取代率的函数关系,修正了损伤本构模型,探讨了损伤变量和损伤变量发展速率与应变的关系.结果表明:本构模型曲线与试验曲线的相关性较高,模型参数a,b与取代率之间满足二次函数关系,分别反映了峰值应力、峰值应变和混凝土的脆性;砖混再生粗骨料混凝土的总损伤D由初始损伤DR和荷载损伤DC组成,掺入砖混再生粗骨料对混凝土造成了初始损伤,总损伤变量随应变增加呈S型单调递增,损伤变量发展速率呈先增大后减少的趋势;砖混再生粗骨料混凝土的配合比设计方法对其损伤程度和损伤变量发展速率有一定影响.     

Response specificity of male pink bollworm moths to different blends and dosages of sex pheromone

Male pink bollworm,Pectinophora gossypiella, were tested in a sustained flight tunnel to 119 blend-dosage combinations of the sex pheromone components, (Z,Z)- and (Z,E)-7,11-hexadecadienyl acetates, which are released by conspecific females in a 6139 ratio. Hierarchical cluster analysis was used to define an area of peak attraction. Within this area males were most sensitive at lower dosages to ratios around the natural blend of components, but exhibited peak response levels at higher dosages to a wide range of blends, with a shift in blend preference to higherZ,Z isomer ratios at the highest dosage tested (10 mg). Male response specificity appeared to be influenced exclusively by a threshold for initiation of upwind flight, and not arrestment of upwind flight. The results are compared with those of another species, the Oriental fruit moth.     

Attitudes toward self-care among practicing physicians

Self-care, although growing as a concept and a movement among providers and consumers, has not been studied systematically in any dimension. Because of the potential role of physicians in establishing the credibility and acceptability of self-care interventions and practices, an exploratory investigation was launched to develop an attitude instrument, to describe the degree to which practicing physicians in a community favor self-care, and to explore some of the correlates of the attitudes expressed. A 13-item attitude scale was developed. Physicians with the most favorable attitudes were most likely to have come from a Jewish religious background, to be under 46 years old, to have health beliefs which reflect an internal locus of control, and to be in a group practice or clinic. Physicians with the least favorable attitudes came from Protestant backgrounds, were 46 to 63 years old, had externally controlled health beliefs, and practiced medicine alone.     

Formation mechanism and growth of MNbO3, M=K,Na by in situ X‐ray diffraction

Hydrothermal synthesis is a well‐established method to produce complex oxides, and is a potential interesting approach to synthesize stoichiometric lead‐free piezoelectric K_0.5Na_0.5NbO₃. Due to challenges in obtaining the desired stoichiometry of this material, more knowledge is needed on how the end‐members, KNbO₃ and NaNbO₃, are nucleating and growing. Here, we report on the formation mechanisms and growth during hydrothermal synthesis of KNbO₃ and NaNbO₃ by in situ synchrotron powder X‐ray diffraction. We show that tetragonal KNbO₃ crystallites form from dissolved T‐Nb₂O₅ at 250°C‐300°C and 250 bar while orthorhombic NaNbO₃ forms via several crystalline intermediate phases at 225°C‐325°C and 250 bar. The crystallite size of KNbO₃ is decreasing while the crystallite size of NaNbO₃ is increasing with increasing temperature, demonstrating that the presence of intermediate phases is highly important for the nucleation and growth of the final product. The different crystallization schemes explain the challenge in obtaining stoichiometric K_0.5Na_0.5NbO₃ by hydrothermal synthesis.     

Effect of water soluble PVA on the microstructure characteristics of C-S-H formed in Na<Subscript>2</Subscript>SiO<Subscript>3</Subscript>-Ca(NO<Subscript>3</Subscript>)<Subscript>2</Subscript> solution system

The structure characteristics of hydrated calcium silicate synthesized by solution reaction method with the existing of water soluble polymer polyvinyl alcohol(PVA)are investigated.Using Na 2 SO 3 and Ca(NO 3 ) 2 as the main raw materials,in the condition of 2%(in weight)addition of PVA and the water to solid ratio of 20,hydrated calcium silicate samples(Ca/Si=1.0 and 1.5)were prepared with 60℃water bath.IR,BET,XRD and SEM methods were used to study the microstructure of the hydration products.The results s...