校外数学活动中的探究性学习研究

数学科学历来是自然科学和社会科学的基础,作为"人类知识活动留下来最具威力的知识工具",高度发展的数学思维已成为人类社会进步的重要标志,更是培养学生科学素养的极好承载体. 　　……     

自然灾害研究中几个观念问题的讨论

本文从人类生活环境系统的整体观角度讨论了自然灾害的两重性、关连性及人类圈之形成和生态环境保护问题。认为自然灾害从短时间尺度和小范围看是灾变, 从长时间尺度和大范围看是一种自调节、自平衡过程；自然灾害与人类社会存在着双向效应关系；自然灾害的关联性(群发共生现象)是由其同源性、链发性和韵律性决定的；人类圈是地球演化进入新阶段的产物, 它具有进行层次深、作用强度高、活动领域宽和通过信息实现调控的特点。建立上述观念, 对灾害研究、减轻灾害损失, 走可持续发展的道路, 都具有重要意义。     

航天·军事·展望

 50年代末,航天技术的兴起及其迅速发展,使人类活动突破了地球大气的屏障,进入到一个新的境界.航天技术的迅猛发展,形成了一门新兴的综合学科,成为现代高科技领域里一个重要的分支.     

QSC-1、QSC-2型超声驱鼠器

老鼠为人类之大敌.历来人类控制鼠害是用捕杀和毒杀的方法,收到一定效果.但由于老鼠生性狡猾、行动敏捷、生存力强、繁殖率高,鼠害仍然普遍存在.在一些特别需要防止老鼠的场所,如图书资料库、计算机房、电器控制室、药品库以及其它仓库、饭馆、食堂等,除捕杀外,驱鼠也是一种保护物资、防止事故、减少     

Interest-Driven Model for Human Dynamics

Empirical observations indicate that the interevent time distribution of human actions exhibits heavy-tailed features. The queuing model based on task priorities is to some extent successful in explaining the origin of such heavy tails, however, it cannot explain all the temporal statistics of human behavior especially for the daily entertainments. We propose an interest-driven model, which can reproduce the power-law distribution of interevent time. The exponent can be analytically obtained and is in good accordance with the simulations. This model well explains the observed relationship between activities and power-law exponents, as reported recently for web-based behavior and the instant message communications.     

珠心算实用价值与发展方向的研究

<正>"人有两个宝,双手和大脑。双手会做工,大脑会思考。用手不用脑,事情办不好;用脑不用手,啥也办不到。一切创造靠劳动,劳动要靠手和脑。"这首儿歌充分说明了手和脑相互配合的重要性。正是手和脑都充分发挥了作用,才使我们人类文明向前迈进了一大步。而     

改革的重点和突破口:落实《宪法》所赋予公民的言论出版自由

马克思认为"发表意见的自由是一切自由中最神圣的,因为它是一切的基础。"新闻出版自由是"人类精神的特权",是"普通的权利"和"普遍自由",而不是"个别人物的特权"。毛泽东也说过"人民的言论、出版……自由,是最重要的自由。"具体来说,新闻出版自由,就是媒体主要由民间出资、民间所有、民间经营、民间分利,独     

在太阳系外找到一颗类地球行星

在太阳系外找到一颗适合人类居住的行星,是天体物理学家长期以来的梦想。适合人类居住,通常要求有液态水,这相应地要求:行星到母恒星的距离在一定的范围之内。按照最近Dumusque等在Nature周刊发表的研究报告,事情或许有了一定的眉目。研究者宣称,发现了一颗类地球太阳系外行星,它围绕半人马座α双星之一(B星)运转,半人马座α双星属于最接近太阳系的恒星,离我们仅4光年远。     

Modulation of electroencephalograph activity by manual acupuncture stimulation in healthy subjects:An autoregressive spectral analysis

To investigate whether and how manual acupuncture(MA) modulates brain activities,we design an experiment where acupuncture at acupoint ST36 of the right leg is used to obtain electroencephalograph(EEG) signals in healthy subjects.We adopt the autoregressive(AR) Burg method to estimate the power spectrum of EEG signals and analyze the relative powers in delta(0 Hz-4 Hz),theta(4 Hz-8 Hz),alpha(8 Hz-13 Hz),and beta(13 Hz-30 Hz) bands.Our results show that MA at ST36 can significantly increase the EEG slow wave relative power(delta band) and reduce the fast wave relative powers(alpha and beta bands),while there are no statistical differences in theta band relative power between different acupuncture states.In order to quantify the ratio of slow to fast wave EEG activity,we compute the power ratio index.It is found that the MA can significantly increase the power ratio index,especially in frontal and central lobes.All the results highlight the modulation of brain activities with MA and may provide potential help for the clinical use of acupuncture.The proposed quantitative method of acupuncture signals may be further used to make MA more standardized.