人体有氧能力的研究   总被引：3，自引：1，他引：3  

陆绍中 《浙江体育科学》1999,21(1):2-12

本文概述了国内外有关儿童少年最大吸氧量的自然增长规律及其性别差异；并着重阐述了人体有氧能力与耐力运动项目成绩的关系。并根据研究数据和国内外学者的同类研究的数据，进行非线性回归模型的最小二乘拟合，建立了予测13～岁男性最大摄氧量的公式。本文还首次提出了最大摄氧量平台（VO2maxPD）的概念，进而深入的讨论了VO2max、VO2maxPD和VO2AT三者的关系。  相似文献   

碘化钠促进的2-溴代苯并呋喃的氰化反应研究     

周丽  周密  王传虎 《廊坊师范学院学报(自然科学版)》2013,(6):42-44

2-氰基苯并呋喃类化合物通常具有很强的生物活性,常用于药物分子和天然产物的构建。2-溴苯并呋喃类化合物在碘化钠做促进剂的条件下与氰化亚铜发生氰化反应,一步得到2位被氰基取代的呋喃衍生物。该方法实现了无过渡金属催化剂的溴代杂环化合物的氰化反应,有效减少了过渡金属催化剂对产品的污染。  相似文献   

β-receptor blocker influences return of spontaneous circulation and chemical examination in rats during cardiopulmonary resuscitation     

Xiao-jing Zhao  Zhuo Pen  Ping Li  Er-xiu Chen  Jian Liu  Yan-xia Gao  Yun-xia Ren  Li-jun Li 《Journal of Zhejiang University. Science. B》2013,14(6):505-510

Objective

We investigated the influence of β-receptor blocker metoprolol on return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR) in rats with induced myocardial infarction (MI).

Methods

Male Sprague-Dawley rats were randomly divided into three groups: the sham-operated group, the MI group without metoprolol, which was fed the vehicle, and the MI+metoprolol group receiving intragastric metoprolol. Each group was further divided randomly into three subgroups, depending on the dosage of epinephrine administered during subsequent CPR applied after the induction of asphyxial cardiac arrest.

Results

The ROSC rate was significantly decreased in the low dose subgroup of MI group, unchanged in the medium dose subgroup of MI group, and significantly decreased in the high dose subgroup of MI group, compared with the same dose subgroup of sham-operated group. MI+metoprolol group had a lower ROSC rate than MI group in the medium dose subgroup, and a higher ROSC rate than MI group in the high dose subgroup. There was no difference in blood K⁺ values of successful rats between MI group and MI+metoprolol group. The rats with successful CPR had lower blood K⁺ values than rats with unsuccessful CPR in each of the three treatment groups.

Conclusions

Metoprolol administered to MI rats over a long period significantly improved ROSC rates under an appropriate dose of epinephrine during CPR. An increasing high blood K⁺ value would attenuate the rate of a successful CPR.  相似文献   

层状硫化物中晶格失配对热电性能影响的理论研究     

张琨  张睿智 《石家庄学院学报》2013,(6):5-8

层状型的金属硫化物(SnS)1.2TiS2是一种新型的热电材料,其结构是由SnS层和TiS2层(一种自然超晶格)相叠加而形成.在这些热电材料中,发现了不同化合物的纳米化叠加态,由于这些沿层面叠加的超晶格的特殊性质,在不影响电子输运的情况下,可使声子的输运减小到最小,从而提升了材料的热电性能.计算了(SnS)1.2TiS2的电子结构与声子结构,通过对纯TiS2体材料与(SnS)1.2TiS2中的TiS2层的电子、声子结构的对比,证实了SnS插层对TiS2层的电子结构及电学输运性质影响很小.这些发现有利于提高层状材料的热电性能.  相似文献   

Thanksgiving     

Sandra K. Roe 《Cataloging & classification quarterly》2013,51(2):135-136

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PCC Practice for Assigning Uniform Titles for Motion Pictures: Principle versus Practice     

Peter H. Lisius 《Cataloging & classification quarterly》2013,51(8):869-893

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Peoples of Melanesia     

《Cataloging & classification quarterly》2013,51(4):47-51

The mnemonic principles of the Dewey Decimal Classification were violated when Table 5 (Racial, Ethnic and National Groups) was introduced. Suggestions are presented to restore such principles to a large area of the South Pacific with particular reference to Melanesia.  相似文献   

PCC Practice for Assigning Uniform Titles for Television Programs: Principle versus Practice     

Peter H. Lisius 《Cataloging & classification quarterly》2013,51(5):550-579

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构建以自助服务为导向的现代图书馆     

陈武  姜爱蓉 《大学图书馆学报》2013,(3):93-96

自助服务已经成为图书馆服务的一种重要形式.清华大学人文社科图书馆在建设之初就充分考虑了自助服务的需求,根据读者需求和自身特点,在实施了统一用户认证信息库、公告发布系统和电话咨询系统的基础上,提供了自助借还书、24小时自助还书窗口、自助缴纳超期罚款、自助文印服务、自助机位管理系统、自助研读间预订、自助阅览座位管理和开放密集架书库等服务,尝试构建一个以自助服务为导向的现代图书馆.  相似文献   

A Vocabulary Learning Tool for L2 Undergraduates Reading Science and Technology Textbooks     

Chihcheng Hsu  Fang-Chuan Ou Yang 《International Journal of Science Education》2013,35(7):1110-1138

Students of English as a second language who major in science and technology use English-language textbooks to ensure that they can read English materials upon graduation. Research indicates that teachers spend little time helping these students on the linguistic complexity of such textbooks. Vocabulary, grammar, and article structure are elements of this complexity, but to many students, these elements can be akin to locked doors. This study presents MyVLS-Reader, which focuses on unlocking the first of these doors—vocabulary—while assisting in reading. With explicit vocabulary learning, students learn and memorize individual vocabulary, but the context is lost if the depth of learning discards context. In implicit vocabulary learning, students acquire vocabulary through repeated exposure to contexts, but repeated encounters with new words are required. Few e-learning systems combine both vocabulary-learning approaches. MyVLS-Reader achieves such synergy by (1) using a keyword setting to provide context-matched vocabulary explanation while reading and (2) embedding multiple learning choices, such as keyword setting, the review and memorization of explicit vocabulary, and the option to ask instructors. This study includes two rounds of evaluations: (1) an evaluation of the learning achievements of control and treatment groups and (2) a quantitative and qualitative investigation of perceptions regarding the use of MyVLS-Reader. The evaluation results indicate that the treatment group developed a better vocabulary than the control group in significantly less time. The use of MyVLS-Reader also slightly improved higher-order thinking skills. This result suggests that MyVLS-Reader can effective assist students in building their vocabulary while reading.  相似文献