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121.
The mechanical softening behaviour of micrometre-scale metals (free-standing metal foils and wires) with decreasing either the geometrical or the microstructural scale (i.e. the smaller, the weaker) has recently been reported. Here, we present a mechanism-based model to understand the softening behaviour, which is based on competition between the effects of surface grain relaxation and the interior grain strengthening effect. The model describes well the yield stress of Cu foils with different ratios of the thickness to grain size. 相似文献
122.
鼻咽癌是我国高发恶性肿瘤之一,发病率为头颈部恶性肿瘤之首。鼻咽癌对放疗、化疗均敏感。单纯的放射治疗虽然能够使早期患者获得很好的局部控制率,但是对于局部晚期患者而言,其5年生存率难以令人满意,治疗失败主要是因为区域复发和远处转移。化学治疗对放疗起到了补充作用,临床应用目前主要有同期化疗、辅助化疗、诱导化疗三种。本文对过去20年间化疗在局部晚期鼻咽癌治疗中的应用归纳总结。 相似文献
123.
知情同意作为生命伦理的重要原则,在基因研究中同样占据重要的地位,由于基因研究中知情同意的异质性,在基因研究中面临着诸如如何理解其知情同意的异质性、群体知情同意、基因知情与基因隐私、利益冲突等问题.通过分析基因研究中知情同意的特殊性,综合国内外此领域的已有研究,运用理论联系实际的方法,得出结论认为,只有正确区分基因知情与基因隐私的权利主体,用伦理规范来解决利益冲突,在发展中不断完善知情同意,才能够取得科技与伦理的共赢. 相似文献
124.
《管子》认为,治理国家既要采用怀柔政策,主张为政者"先之以德",通过整饬四维来形成良好的社会风尚;又强调"法不可不审",主张通过严刑峻法来树立君主的权威,赏罚严明,使人们严格遵守各项法令制度,坚持"且怀且威",礼法并重,其思想对现代社会有很好的启迪意义。 相似文献
125.
《淮南子》对墨子持有复杂的政治认识与态度,这在秦汉思想史上具有一定的代表性。从黄老道家的根本立场出发,“批墨”是《淮南子》政治思想的基本主张,但与此同时,《淮南子》也内在地显示出“尊墨”的政治情怀,进而试图对墨子政治思想有所借鉴和汲取,达到“融墨”之理论目的。对待墨子及其政治思想的历史态度,既凸显出《淮南子》立足黄老,融通诸子的博大精神,也彰显出墨子在秦汉政治思想发展中独特的历史影响。 相似文献
126.
127.
This is a study of the development trend of creative scientific problem finding (CSPF) ability of a sample of 1,367 elementary, middle, and high school students in two Chinese cities. Students were instructed to generate science related questions in both open and closed conditions with responses scored for Fluency, Flexibility, and Originality. Results suggest that CSPF ability has a developmental trend characterized by a significant leap in the 5th grade, followed by a steady advance until it peaked in the 8th grade, and then declined and stabilized in the high school years (9th–11th grades). No difference between male and female students was found. The type of instruction showed significant differential influence on CSPF and its development. 相似文献
128.
Pedro Bezerra Shi Zhou Zachary Crowley Allan Davie Robert Baglin 《Journal of motor behavior》2013,45(5):413-421
It is known that electromyostimulation (EMS) alone or superimposed over voluntary contraction (EV) can effectively improve muscle strength. However, the effect of this type of training on the ability to control force production at submaximal levels is unknown. The authors examined the effects of EV training on steadiness in force production of knee extensors and flexors in older adults. Forty participants, including 20 men and 20 women, 60–77 years of age, were randomly allocated into a control group (CG) and an electromyostimulation superimposed over voluntary contraction (EVG) group. The EVG performed 30 bilateral isometric knee extension and flexion contractions per session, 3 training sessions per week, for 6 weeks. The variations in force production, expressed in absolute (standard deviation [SD]) and relative (coefficient of variation [CV]) terms, were assessed in isometric contractions at 5%, 15% and 25% maximal voluntary contraction (MVC) levels. Results indicated that MVC increased in knee extension and flexion in EVG (p < .05) after the training; steadiness CV also improved at 15% MVC in knee flexion (p < .05) but no significant changes were found in knee extension and steadiness SD. The training-induced changes in MVC were not correlated to steadiness CV that might indicate different mechanisms underlying these adaptations. 相似文献
129.
Yu Tian Zong Xin Guo Jie Ru Shi Yu Long Bian Pi Guo Han 《The Journal of psychology》2013,147(8):529-547
AbstractThis 1-year longitudinal study examined the bidirectional mediating role of loneliness in the association between shyness and generalized pathological Internet use (GPIU) in a sample of 291 Chinese university students (143 men, mean age =?19.07?years). A fully cross-lagged panel design was used in which shyness, loneliness, and GPIU were assessed at 3 time points separated by 6-month intervals (named T1, T2, and T3). The results indicated that relationships among shyness, loneliness, and GPIU were dynamic and bidirectional. Specifically, T1 shyness positively predicted increased T2 loneliness, T2 shyness positively predicted increased T3 loneliness, and T2 loneliness positively predicted increased T3 shyness. Additionally, T1 GPIU positively predicted increased T2 loneliness, T2 GPIU positively predicted increased T3 loneliness, and T2 loneliness positively predicted increased T3 GPIU. Loneliness was found to play a bidirectional mediating role in the association between shyness and GPIU. Specifically, T1 shyness and T3 GPIU were mediated through increased loneliness at T2, and T1 GPIU and T3 shyness were mediated through increased loneliness at T2. Furthermore, relationships among shyness, loneliness, and GPIU were the same across the 2 groups, with the strength of relationships being stronger for men. 相似文献
130.
This study tested the greater male variability hypothesis in creative thinking with a Chinese student sample in Mainland China. The Test for Creative Thinking-Drawing Production (TCT-DP) was administered to 627 Chinese adolescent boys (n = 332) and girls (n = 295). Results using the boy/girl variance ratio (VR) generally supported the hypothesis that boys have greater variability than girls in creativity test performance. However, results using the boy/girl ratios from different regions of the creativity score distribution revealed a pattern of male superiority. While boys significantly outnumbered girls in the higher extremes, girls tended to outnumber boys in the central region and the lower extremes. Results from an analysis of the means lent further support to the findings of male superiority. Plausible explanations for greater male variability and male superiority in Mainland China are proposed. The theoretical and practical implications of the findings are discussed. 相似文献