桥塞坐封过程仿真模拟研究

桥塞作为井下封层技术的关键设备,由于它施工工序少、周期短、卡封位置准确而得到了广泛应用。针对设计的可钻式非金属桥塞坐封过程开展模拟研究,涉及弹塑性材料接触、超弹性材料接触和非金属材料动态断裂的非线性动力学问题,利用有限元法建立该桥塞全尺寸模型和所有部件之间的广义接触关系,通过有限元模拟动态坐封过程获得桥塞各部件运动变形特性、桥塞与套管之间的密封特性和动态坐封力等数据,该桥塞坐封完成时,坐封机构部件轴向位移110 mm,坐封力约45 kN。模拟坐封也为进一步优化该型桥塞的结构和评估坐封性能提供了理论依据,对该型桥塞的推广应用奠定了基础。     

Mixed-effects Models with Skewed Distributions for Time-varying Decay Rate in HIV Dynamics

After initiation of treatment, HIV viral load has multiphasic changes, which indicates that the viral decay rate is a time-varying process. Mixed-effects models with different time-varying decay rate functions have been proposed in literature. However, there are two unresolved critical issues: (i) it is not clear which model is more appropriate for practical use, and (ii) the model random errors are commonly assumed to follow a normal distribution, which may be unrealistic and can obscure important features of within- and among-subject variations. Because asymmetry of HIV viral load data is still noticeable even after transformation, it is important to use a more general distribution family that enables the unrealistic normal assumption to be relaxed. We developed skew-elliptical (SE) Bayesian mixed-effects models by considering the model random errors to have an SE distribution. We compared the performance among five SE models that have different time-varying decay rate functions. For each model, we also contrasted the performance under different model random error assumptions such as normal, Student-t, skew-normal, or skew-t distribution. Two AIDS clinical trial datasets were used to illustrate the proposed models and methods. The results indicate that the model with a time-varying viral decay rate that has two exponential components is preferred. Among the four distribution assumptions, the skew-t and skew-normal models provided better fitting to the data than normal or Student-t model, suggesting that it is important to assume a model with a skewed distribution in order to achieve reasonable results when the data exhibit skewness.     

大型航空制造企业技术改造项目管理新模式

技术改造及其项目管理是大型航空制造企业经营管理活动中的重要任务之一。企业通过技术 改造项目改进生产条件和生产工艺,增强军民用航空产品的研制能力。论文根据技改项目管 理的特点,运用系统动力学方法建立技改项目全生命周期动力学模型,对技改项目生命周期 的全过程进行动态仿真,为管理者提供信息和决策支持。最后,结合工作流技术的优点,建 立了基于工作流技术的技改项目管理协同平台原型     

生命价值观下的“同命同价”与“同命不同价”

我国目前正处于通过创制及健全相关民事立法——侵权责任法来积极应对各种事故导致人身与财产损害后果的关键时期。几年前最高人民法院关于人身侵权死亡赔偿的一个司法解释引发了社会上“同命同价”与“同命不同价”的激烈争论。生命双重价值观命题的提出对于理性回应“同命同价”与“同命：再同价”的质疑及剖析相关问题，具有一定的启示意义。     

Comparing measures of general and abdominal adiposity as predictors of blood pressure in college students

Objective: To compare anthropometric measures of body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and sagittal abdominal diameter (SAD) as predictors of blood pressure in college students. Participants: Students (N = 116) were recruited from November 2012 to May 2014 at an urban university and rural community colleges. Methods: Students underwent a brief physical examination during which anthropometric measures were obtained and blood pressure was measured. Covariates were measured using self-reported questionnaires. Hierarchical multiple linear regressions were used for the data analysis. Results: All anthropometric measures were predictive of systolic (SBP) and diastolic blood pressure (DBP). WC was the strongest predictor of SBP (β = .582, p < .01) explaining an additional 3–4% of the variance than BMI, WHtR, or SAD. The measures were similar in predicting DBP. WC predicted SBP independent of BMI. Conclusions: Clinicians should consider using WC to assess the risk for hypertension in college students.     

Separating Spheres? Diverging Trends in Youth's Gender Attitudes About Work and Family

The authors investigated whether trends in attitudes about gender were consistent with the gender stall primarily occurring in the family domain and examined potential mechanisms associated with changing gender norms. Using data from Monitoring the Future surveys (1976–2015), the authors assessed three components of trends in youth's beliefs about gender: the marketplace, the family, and mothers' employment. Findings showed continued increases in egalitarianism from 1976 through the mid‐1990s across all three dimensions. Thereafter, support for egalitarianism in the public sphere plateaued at high levels, rising support for mothers' employment persisted at a slower pace, and conventional ideology about gender in families returned. The changing demographic composition of American high school students did not account for the gender attitude trends. Youth's mothers' employment and increased education were related to increased egalitarianism. Changes in population averages of mothers' employment and educational attainment were only weakly associated with increases in egalitarian attitudes.     

《我的安东妮亚》“回归主题”的多重分析

在薇拉·凯瑟小说《我的安东妮亚》第四卷结尾处,主人公吉姆.波顿出人意料地离弃了他的恋人安东妮亚,20年后又返回西部大草原看望她。吉姆的这一"离"一"回/归",多年来一直是学术界关注的焦点。许多学者纷纷从各种视角,如女性主义、酷儿理论或生态文学解读吉姆的"回归"。但是,综观国内外学者对该作品的研究,笔者发现他们只是从单一视角去研究分析该作品的"回归主题",因此,本文将从精神分析、文化研究、女性主义和生态批评等视角对该主题进行多重分析。     

21世纪再谈编辑主体意识的重建与实现

发挥主体意识在编辑工作中的能动性是提高出版物质量的关键。现代编辑主体意识应包括信息意识、精品意识、市场竞争等。只有充分发挥编辑的主体意识和主导作用，才能够实现出版物的基本属性和社会价值。