科创中国

我们经常遇到这样的情况,学生在学习物理知识时轻松、愉快,学习兴趣浓厚,可在解决实际问题时,往往一筹莫展,束手无策.究其原因是,在教学中重知识轻能力、学不致用.这种反差现象使我意识到:学生仅仅是懂得了物理知识还不足够,还要培养学生应用知识解决实际问题的能力,特别是知识迁移的能力.学生在学习过程中通过举一反三、触类旁通,把学到的某些物理原理、物理知识应用到学习新的知识或解决问题的活动中去,这就实现了知识的迁移.

透射电子显微镜是生物医学、化学、农林和材料学等领域进行科学研究的重要工具.透射电子显微镜技术中,要获得理想的实验结果,不仅要有高分辨率、高放大倍数的电子显微镜,还需要超微结构保存良好、厚度合适、反差适中的样品.没有适当的反差,就无法辨认生物组织的微细结构.如何在制样与观察时增加反差是一个值得重视的问题.本实验将扫描电镜"喷镀"技术应用于增加透射电镜样本反差,

文化的传播需要一定的载体.体育传播是以竞技比赛、体育活动、娱乐休闲等为载体的交流和信息交换行为.我国古代体育文化总是附着于军事、竞技游戏以及养生健身、侠义精神以及宗教仪式等特定的社会现象中继承和传播的.

Fear?and?anxiety?may?be?adaptive?responses?to?life-threatening?situations,?and?animals?may?communicate?fear?to?others?vocally.?A?fundamental?understanding?of?fear?inducing?sounds?is?important?for?both?wildlife?conservation?and?management?because?it?helps?us?understand?how?to?design?repellents?and?also?how?(and?why)?animals?may?be?negatively?impacted?by?anthropogenic?sounds.?Nonlinear?phenomena--sounds?produced?by?the?desynchronization?of?vibrations?in?a?sound?production?system-are?commonly?found?in?stress-induced?animal?vocalizations,?such?as?in?alarm?calls,?mobbing?calls,?and?fear?screams.?There?are?several?functional?hypotheses?for?these?nonlinear?phenomena.?One?specific?hypothesis?is?the?unpredictability?hypothesis,?which?suggests?that?because?nonlinear?phenomena?are?more?variable?and?somewhat?unpredictable,?animals?are?less?likely?to?habituate?to?them.?Animals?should,?therefore,?have?a?prolonged?response?to?sounds?with?nonlinear?phenomena?than?sounds?without?them.?Most?of?the?studies?involving?nonlinear?phenomena?have?used?mammalian?subjects?and?conspecific?stimuli.?Our?study?fo-?cused?on?white-crowned?sparrows?(Zonotrichia?leucophrys?ssp.?oriantha)?and?used?synthesized?acoustic?stimuli?to?investigate?behavioral?responses?to?stimuli?with?and?without?nonlinear?phenomena.?We?predicted?that?birds?would?be?less?relaxed?after?hearing?a?stimulus?with?a?nonlinear?component.?We?calculated?the?difference?from?baseline?of?proportion?of?time?spent?in?relaxed?behaviors?and?performed?pair-wise?comparisons?between?a?pure?tone?control?stimulus?and?each?of?three?experimental?stimuli,?including?a?frequency?jump?up,?a?frequency?jump?down,?and?white?noise.?These?comparisons?showed?that?in?the?30q50?s?after?the?playback?experiment,?birds?were?significantly?less?relaxed?after?hearing?noise?or?an?abrupt?frequency?jump?down?an?octave?but?not?an?abrupt?frequency?jump?up?an?octave?or?a?pure?tone.?Nonlinear?phenomena,?therefore,?may?be?generally?arousing?to?animals?and?may?explain?why?these?acoustic?properties?are?commonly?fou

如今,报知春节迫近的已经不再是腊八粥的香味,而是媒体上充满压力的热火朝天的春运了.每入腊月,春运有如飓风来临,很快就势头变猛,愈演愈烈;及至腊月底那几天,春运可谓排山倒海,不可阻遏.每每此时我都会想,世界上哪个国家有这种一年一度上亿人风风火火赶着回家过年的景象?

二语词汇习得中的石化现象直接阻碍了学习者的语言表达及运用能力.二语习得者如果过分地依赖于高频词汇,结果则是其产出性词汇无论在广度还是深度上都很难进一步提高.因此,教师应该鼓励并在教学中采用一定的教学策略促使学生尽量多运用刚学的新词,而非一味依赖以往熟知的高频词汇,使学生的语言表达更加准确、恰当和丰富,从而促进其英语水平的不断提高.

改革开放35年来的中国建筑设计,成就说不完,问题议不断.工程院的课题《当代中国建筑设计现状与发展研究报告》及《蓝皮书》,既广又深地对此做了描述,并提出了许多解决问题的可行办法,我们感同身受.《研究报告》和《蓝皮书》,提到的那些负面建筑现象,可谓触目惊心.能不能解决?怎么解决?应该是我们要进一步思考和行动的核心问题.解决建筑师内部的问题固然需要下大力气,但许多问

脂酸镁又名十八酸镁,在粉末直接压片工艺中具有重要作用,但是硬脂酸镁的使用,往往会对片剂产生一定的软化效应.从直压辅料的分类、物料粒径大小、辅料与硬脂酸镁的混合时间以及硬脂酸镁使用浓度等方面,简要分析产生此种软化效应的原因以及影响其大小的因素,以期为实际生产中提高粉末直接压片工艺有所借鉴和帮助.

《云南少数民族文化传承论纲》一书对民族文化传承问题进行了详尽的分析,并在讨论中作出了演绎和逻辑展开,既研究文化现象,又关注现实问题,内容所及和探讨远远超出了云南少数民族文化本身.本书分为理论篇、论证篇和开发篇三部分.