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11.
为了提高水下大长径比圆柱壳低频振动响应和辐射声功率的计算效率,该文提出了一种用水下梁模型等效计算的方法。该等效模型基于欧拉梁理论,采用附加水质量近似流固耦合作用,通过计算梁的等效杨氏模量系数,使其与圆柱壳的梁式弯曲振动模态对应。计算表明,对大长径比简支圆柱薄壳(L/a>20),等效梁杨氏模量系数主要取决于结构长径比,而厚度对其的影响甚小。文中还给出了不同长径比圆柱壳前五阶模态频率的等效杨氏模量系数曲线,利用梁模型并结合此曲线,可准确预报水下圆柱壳低频域辐射声功率和圆柱壳的梁式弯曲振动模态。  相似文献   
12.
严歌苓,当代北美“新移民文学”的代表性作家,越来越受到人们的关注。她的小说着眼于女性,解剖女性的生命与情感,从多个角度对人性进行了深入的思考。通过分析移民小说《扶桑》和《少女小渔》中女主人公形象,来探讨处于弱势的女性体现的最原始最本真的母性。  相似文献   
13.
Physical inactivity of children and adolescents is a major public health challenge of the modern era but, when adequately promoted and nurtured, active travel offers immediate health benefits and forms future sustainable and healthy travel habits. This study explores jointly the choice and the extent of active travel of young adolescents while considering walking and cycling as distinct travel forms, controlling for objective urban form measures, and taking both a “street-buffer” looking at the immediate home surroundings and a “transport-zone” looking at wider neighborhoods. A Heckman selection model represents the distance covered while cycling (walking) given the mode choice being bicycle (walk) for a representative sample of 10–15 year-olds from the Capital Region of Denmark extracted from the Danish national travel survey. Results illustrate the necessity of different urban environments for walking and cycling, as the former relates to “street-buffer” urban form measures and the latter also to “transport-zone ” ones. Results also show that lessening the amount and the density of car traffic, diminishing the movement of heavy vehicles in local streets, reducing the conflict points with the density of intersections, and intervening on crash frequency and severity, would increase the probability and the amount of active travel by young adolescents. Last, results indicate that zones in rural areas and at a higher percentage of immigrants are likely to have lower probability and amount of active travel by young adolescents.  相似文献   
14.
文章阐述了当前各高职院校青年教师的现状及各大高职院校对其的培养现状,并从思想道德、教学能力、科研能力、双师素质以及综合能力等五个方面提出了高职院校青年教师培养策略,具有一定的借鉴意义。  相似文献   
15.
本研究在为制定城市公交司乘人员的管理方案提供心理学依据,人员进行了相关调查。结果中等水平;性别、工作时间度有不同程度的影响。表明:城市公交青年司乘人员的一般自我效能通过问卷形式对城市公交青年司乘感、工作压力和满意度均处于一般学历等因素对城市公交青年司乘人员的一般自我效能感、工作压力和工作满意  相似文献   
16.
The 2000s was a decade of transitions for teens and young adults. In comparison with previous generations of youth, those living in the developed world (i) faced the harshest economic climate in decades, (ii) lived with their parents longer and were more likely to return back home as young adults, (iii) used information and communication technologies (ICTs) extensively, and (iv) in the U.S., were subject to increasingly stringent graduated driver’s licensing (GDL) regulations. All were dramatic societal changes to be sure, but how did they affect youth travel behavior? Some argue dramatically and enduringly, but usually with fragmentary evidence. We examine data from the three most recent U.S. national travel surveys and find that, with one exception, after controlling for personal, household, locational, and travel factors, the effects of factors associated with various societal trends on person-kilometers traveled (PKT) are surprisingly muted. The exception is that decreased employment is associated with substantially lower PKT; however, this effect is 32% greater among older (ages 27–61) than younger (ages 20–26) adults, suggesting that economic factors, rather than changes in youth travel preferences, were at the root of declines in personal travel in the U.S. during the 2000s.  相似文献   
17.
张博文  刘军鹏  徐强 《船舶工程》2019,41(12):113-118
为了揭示材料主要力学性能对深海耐压结构极限承载能力的影响规律,本文以完整球壳为研究对象,采用非线性有限元方法,开展了材料力学特性变化对极限强度的影响研究。通过大量数值计算与归纳分析,得到了材料屈服强度和杨氏模量随厚径比变化对球壳极限强度的影响规律,研究发现随着厚径比的增加,材料刚度特性对结构极限强度的影响权重逐渐减少,屈服强度影响权重逐渐增加,在此研究基础上本文提出了一种考虑屈服强度变化的球壳极限强度计算新方法,为潜水器耐压结构选材与设计提供参考。  相似文献   
18.
Transport policy in the UK is seeking to promote the development of low carbon transport technology and to encourage people to choose to use low carbon travel options. This paper draws on existing behavioural theories to study young people’s travel behaviour intentions and the influence on these from their knowledge of, and willingness to act on, climate change. The study involved a series of focus groups with young people aged 11-18 years, where attitudes to transport modes, attitudes towards climate change and travel behaviour intentions were discussed. Knowledge and values are established as the key determinants of young people’s attitudes and behaviour intentions towards transport in the context of climate change. More specifically it is established that young people’s values emphasise speed and freedom and that it is important to young people that the mode of transport they choose is reflective of the image they want to portray.  相似文献   
19.
文章深入研究了当前高校青年教师师德建设中存在的困境与问题,分析了产生这些问题的原因,并从健全完善高校师德建设制度、建设良好师德建设环境等方面提出了相应的解决措施,具有一定的借鉴意义。  相似文献   
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