塑料扣件组件注射模设计

分析塑料扣件组件模具设计时的要点与难点,介绍了塑件的配合间隙,强脱结构的设计及浇注系统和模具结构的设计,注塑成型时工艺参数的确定。     

An effect of strength of railway axle steels on fatigue resistance under press fit

High-cycle fatigue tests with an evaluation of fatigue limit were carried out on large model components of bars with press fitted hubs of diameter 63/59 mm. Bars were made of three railway axle steels EA1N, EA4T and 34CrNiMo6 with considerable different strength from 586 MPa to 1041 MPa, respectively. Detection and measurement of crack growth under hubs by ultrasonic method was performed during the tests. In spite of the differences in strength and alloying of tested bars, differences in mean value of fatigue limit were not significant. This result was connected with specific damage mechanism and microcracks initiation under hubs with fretting effects. Short fatigue crack growth under hubs occurred at stress intensity factor range ΔK considerably bellow threshold value ΔK_th of long cracks. Simultaneous growth of main cracks from more than one point of surface circumferential area under hub was quite frequently observed.     

The impact of social comparison information on motivation in patients with diabetes as a function of regulatory focus and self-efficacy.

Objective: Our aim was to determine whether the impact of upward and downward social comparison information on individuals' motivation to manage their diabetes is dependent on their regulatory focus (promotion or prevention focus) and self-efficacy. Design: The hypotheses were examined in a cross-sectional study. Patients with diabetes (N = 234) read a fictitious interview with a fellow patient, either an upward or a downward target, and they filled out questionnaires. Main Outcome Measures: Motivation to work on diabetes regulation. Results: High promotion-focused patients reported more motivation than low promotion-focused patients when confronted with the upward target (positive role model). High prevention-focused patients reported more motivation than low prevention-focused patients when confronted with the downward target (negative role model). This latter finding was qualified by patients' self-efficacy, as it applied only to patients with relatively high levels of self-efficacy. Conclusion: The current study highlights the importance of considering individual differences when using role models to encourage self-care activities in persons with diabetes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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本文介绍了无限传导裂缝井的新压力导数理论图版。这种理论图版在曲线拟合时,垂向刻度自动对齐,且以三条曲线控制,提高了拟合的唯一性,对矿场酸化压裂的效果分析具有实际意义。     

精确计算相对渗透率的方法

用非稳态法进行驱替实验来获得原始实验数据，对数据计算处理后进行曲线拟合，根据拟合曲线求导后得到相对渗透率值，其值的精确程度与选取什么样的数学模型作为拟合函数及曲线拟合时拟合程度是否高密切相关。采用琼斯所作的恒速水驱油试验数据和胜利油田具有代表性的某一岩心试验数据，论证平均含水饱和度与无因次累积注水量的关系为单调上升函数，平均有效粘度与无因次累积注水量的关系为单调下降函数，说明对这２类函数关系的拟合函数的要求是曲线光滑。目前普遍使用多项式进行拟合。高阶多项式拟合函数拐点多，波动严重，据此计算出来的相对渗透率值误差大，在相渗曲线图上表现为曲线出现振荡，不光滑。低阶多项式的拟合系数又太小，据此求得的相对渗透率值不精确。若试验数据完全呈单调性或只有个别数据点形成拐点，可以对拐点或剔除或调整，以保证曲线的单调光滑，再采用三次样条函数进行曲线拟合。这种拟合函数通过绝大多数数据点，拟合程度最高，从而保证了相对渗透率值的精确性。对拐点多、波动剧烈的试验数据，应该从对数函数和指数函数中选取拟合程度最高的函数作为拟合函数，以保证求取的相对渗透率值精确。图３表１参４（郭海莉摘）     

Beyond the F Test: Effect Size Confidence Intervals and Tests of Close Fit in the Analysis of Variance and Contrast Analysis.

This article presents confidence interval methods for improving on the standard F tests in the balanced, completely between-subjects, fixed-effects analysis of variance. Exact confidence intervals for omnibus effect size measures, such as or and the root-mean-square standardized effect, provide all the information in the traditional hypothesis test and more. They allow one to test simultaneously whether overall effects are (a) zero (the traditional test), (b) trivial (do not exceed some small value), or (c) nontrivial (definitely exceed some minimal level). For situations in which single-degree-of-freedom contrasts are of primary interest, exact confidence interval methods for contrast effect size measures such as the contrast correlation are also provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specific Heat of Mg11B2, a Two-Gap Superconductor

We report measurements of the specific heat of Mg¹¹B₂, from 1 to 50 K and in magnetic fields to 9 T, and give the values of parameters relevant to the superconductivity. The superconducting-state electron contribution is dramatically different from that of other superconductors, but the general features are consistent with predictions for a two-gap superconductor, and it can be quantitatively represented by a two-gap model based on BCS thermodynamics. Parameters characterizing the gaps are in good agreement with some spectroscopic determinations, and also with theoretical calculations. An unusually strong magnetic field dependence of the temperature-proportional term in the electron contribution to the vortex-state specific heat is evidently another manifestation of the two gaps.     

Structural contingency theory and individual differences: Examination of external and internal person-team fit.

This article develops and tests a structurally based, integrated theory of person-team fit. The theory developed is an extension of structural contingency theory and considers issues of external fit simultaneously with its examination of internal fit at the team level. Results from 80 teams working on an interdependent team task indicate that divisional structures demand high levels of cognitive ability on the part of teammembers. However, the advantages of high cognitive ability in divisional structures are neutralized when there is poor external fit between the structure and the environment. Instead, emotional stability becomes a critical factor among teammembers when a divisional structure is out of alignment with its environment. Individual differences seem to play little or no role in functional structures, regardless of the degree of external fit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

低渗透油层DST测试卡片解释新方法

针对低渗透油藏低速非达西渗流的特点，充分考虑实测压力的流动期历史和恢复期历史数据及关井后井筒储存效应，建立了新的物理、数学模型；利用有限差分方法求出其数值解，绘制出新型典型曲线图版，提出了解释方法，并进行了实例应用。此方法适用于均质非自喷井，尤其是处理低渗透地层受污染井的结果比较符合地层实际地质情况，其成果的应用对地层改造有一定的指导作用。