基于HyperMesh的活塞网格划分策略研究

网格划分作为有限元数值模拟分析的一个重要环节,它直接影响着后续数值计算求解时间及分析结果的精确性。活塞作为多特征的复杂结构体,其网格划分具有很大的难度。借助于HyperMesh软件强大的CAE建模、网格划分及可视化功能,针对同一活塞几何模型的网格划分和质量检查,对比不同网格条件下模态分析过程和结果的差异,进而阐明了得到高质量活塞网格的处理对策和技巧,为同类型结构的网格划分和最优化分析提供参考。     

海杂波背景下的双参数单元平均恒虚警检测器

介绍了海杂波的幅度分布模型,指出了对于同一门限系数"尖锐"海杂波背景下的虚警率要明显高于噪声背景下的虚警率,提出了双参数单元平均恒虚警(CA-CFAR)检测器的结构框图,仿真分析了其检测性能.最后分别利用双参数CA-CFAR检测器和常规CA-CFAR检测方法对实测数据进行处理和比较,指出在虚警率一定的前提下前者相对于后两者在空间上可以自适应地改变门限系数以有效地抑制海杂波引起的高虚警.     

一类标签细胞种群系统的适定性与稳定性

研究一类标签细胞系统的解,使用泛函分析方法,特别是Banach 上的线性算子理论和半群理论,证明了该系统解的适定性、线性稳定性和指数稳定性.     

“五字诀”优化骨髓穿刺培训体系

骨髓穿刺术是临床常用的四大穿刺术之一,对相关疾病的诊断、治疗和预后有重要意义,但其对操作者理论、技能和心理素质的要求均较高。医学实习生刚刚接触临床,如按照以往的方式教学,熟练掌握骨穿技术需要较长时间。作者以独创的“骨穿五字诀一净准好直快”为核心,实施循证教学,突破了以往的教学瓶颈,在大规模培训中取得了良好的效果。     

Quantile residual life regression based on semi-competing risks data

This paper investigates the quantile residual life regression based on semi-competing risk data. Because the terminal event time dependently censors the non-terminal event time, the inference on the non-terminal event time is not available without extra assumption. Therefore, we assume that the non-terminal event time and the terminal event time follow an Archimedean copula. Then, we apply the inverse probability weight technique to construct an estimating equation of quantile residual life regression coefficients. But, the estimating equation may not be continuous in coefficients. Thus, we apply the generalized solution approach to overcome this problem. Since the variance estimation of the proposed estimator is difficult to obtain, we use the bootstrap resampling method to estimate it. From simulations, it shows the performance of the proposed method is well. Finally, we analyze the Bone Marrow Transplant data for illustrations.     

Estimating the prevalence of low-lumbar spine bone mineral density in older men with or at risk for HIV infection using normal mixture models

Bone mineral density decreases naturally as we age because existing bone tissue is reabsorbed by the body faster than new bone tissue is synthesized. When this occurs, bones lose calcium and other minerals. What is normal bone mineral density for men 50 years and older? Suitable diagnostic cutoff values for men are less well defined than for women. In this paper, we propose using normal mixture models to estimate the prevalence of low-lumbar spine bone mineral density in men 50 years and older with or at risk for human immunodeficiency virus infection when normal values of bone mineral density are not generally known. The Box–Cox power transformation is used to determine which transformation best suits normal mixture distributions. Parametric bootstrap tests are used to determine the number of mixture components and to determine whether the mixture components are homoscedastic or heteroscedastic.     

The predictive role of bone turnover markers for BMD in middle-aged men

Measurement of bone turnover markers has been proposed as a potentially valuable clinical laboratory aid in osteoporosis risk assessment. These markers may allow quantitative evaluation of rates of bone loss, and thereby identify persons at risk for osteoporosis at an earlier stage. As far as we know, this is the longest longitudinal study on bone turnover markers conducted in adult men. The objectives of this study were to determine whether markers of bone formation (type I procollagen amino-terminal propeptide, PINP, and carboxy-terminal propeptide, PICP), and of bone resorption (type I collagen carboxy-terminal telopeptide, ICTP), are predictive of changes in lumbar spine and femoral neck BMD over a 5-year period, and to determine the ability of the bone resorption marker urine amino-terminal telopeptide (NTx) to explain the variance in BMD change over the past 5 years in a group of men 35–69 years old. In this group, NTx was the only marker to correlate significantly with BMD changes at the femoral neck (r = ?0.21), but not at the spine. The use of the biochemical markers studied to predict change in bone density in adult men in middle-aged years is of very limited value.     

智能配电网及其技术需求分析

随着经济的发展、社会的进步、科技和信息化水平的提高以及全球资源和环境问题的日益突出,电网发展面临新课题和新挑战。利用智能配电网技术彻底改造现有的能源利用体系,最大限度地开发电网体系的能源效率是未来智能电网发展的方向。本文针对配电网智能化的要求,给出了智能配电网的定义和特征,提出了功能要求。重点探讨了实现智能配电网的几个关键技术,包括配电网自愈控制、配电网快速仿真与模拟技术、AMI技术、分布式发电与微网技术,为我国智能配电网的进一步研究及实现提供参考。     

Alzheimer's Disease and Older Women

The graying of America suggests that dementia will become "the epidemic of the 21st century." First described in 1907, Alzheimer's Disease (AD) accounts for an estimated two-thirds of all dementia. AD currently has no cure, thus causing a major drain on health care and family resources. Compared to men, women are uniquely affected by AD due to their gender-associated increased risk, longer life span, and roles as caregivers within families and institutions. Living successfully with dementia requires medical and behavioral interventions to manage disruptive symptoms, knowledge to optimize environmental conditions, and caregiver support and savvy to avoid burnout. Strategies for maximizing functioning in older women living with AD are provided.     

Rethinking Women and Their Bodies in the Age of Biotechnology: Feminist Commentaries on the Hwang Affair

Many Korean women felt strongly positive about donating their eggs for Hwang Woo Suk’s research, in spite of the fact that Hwang was accused of fraud. It is said that there is a kind of unique ‘egg donation culture’ among Korean women, which urged them to donate their eggs for his research. However, positing such a Korean ‘egg donation culture’ does not seem to give a sufficient explanation of why so many Korean women were seemingly willing to provide their own eggs for Hwang’s research. Instead, we suggest that egg donation issues in the Hwang affair can be interpreted under the paradoxical context, in which Korean women are situated in the age of biotechnology. On the one hand, the invisibility of women as subjects in the public sphere led to their lack of social control over ova trafficking and made it possible for a huge number of eggs to be supplied secretly for Hwang’s team. The patriarchal structure of family, the myth of economic growth, and the restricted activities of feminist organizations are possible contributors to the invisibility of Korean women. On the other hand, in the practices of bodily technologies such as cosmetic surgery and reproductive technologies, Korean women have been highly visible. With the help of those technological instruments, women have been empowered to own their own bodies and to have them at their disposal. We argue that these dualistic realities of women as egg owners can explain the egg donation culture among Korean women in the Hwang affair.