取代喹啉新化合物的光化学合成

1-N-苯甲酰基-4-氨基-1-氮杂丁二烯在紫外光照射下进行光环化反应,制备了一些文献中未报导过的取代喹啉,全部的新化合物都经元素分析,MS,~1H和~(13)C NMR测定。     

元极图理论在架构设计中的应用

中国的思维认为创造知识的出发点是认识超越对立事物的需要,元极图理论提供了如何了解对立事物间的动态关系及新知识的模式。认为新知识形成于对立事物（阴、阳）相互间的精髓（阳中阴、阴中阳）的和谐统一之中。架构设计中如何运作和设计活动中不同知识加以连通,元极图模式提供了理论框架。     

美国《亚洲学者公报》(1976)“中国革命文学专号”绪言

过去的60年间,世界上最伟大的文化之一——中国文化在一场实质触及社会各方面的深刻革命中得到了改造,目前,当中国为完全掌握其命运、实现其革命理想而继续奋斗时,世界的其余部分,以妒忌,残存的误解、怀疑和钦佩相交织的心情,出神地注视着她.或许,中国革命最不为世界其余部分所理解和赞赏的就是中国新文学艺术的发展.即使在对当前中华人民共和国的文艺状况感兴趣的外界观察家中,对革命的文学艺术也有着截然不同的反应,从完全的敌视到诌媚的赞扬,什么都有,但最典型的反应就是迷惘地耸耸肩膀.甚至在专攻中国文学的西方学者中,认真关注20世纪中国文学作品的人也很少.考虑到现代中国文学仅仅包容了一种源远流长达三千年之久的文学传统的一小部分,上述现象也不十分奇怪.但是学者和其他各界人士对中国不容置疑的引人注目的政治经济成就兴趣却大增,总的说来,对其文艺发展的关注并没有引起相应的增长.     

印度喀拉拉邦的教育分权计划:理想与现实

许多发展机构的文献都提倡通过教育分权管理策略来促进地方参与教育的行动。尽管这种倡导有着长远的历史,但事实上,在许多教育体系中的教育分权计划并没有取得成功。印度喀拉拉邦的“人民分权计划运动”试图采用一个多方位的“大爆炸”方式实施分权计划,它虽有力量,但也存在局限性,其主要障碍是地方当局的技术能力有限,以及未转变参与者态度,未向参与者充分证明分权是符合他们需要的。     

Speed and surface steepness affect internal tibial loading during running

Background:Internal tibial loading is influenced by modifiable factors with implications for the risk of stress injury.Runners encounter varied surface steepness(gradients) when running outdoors and may adapt their speed according to the gradient.This study aimed to quantify tibial bending moments and stress at the anterior and posterior peripheries when running at different speeds on surfaces of different gradients.Methods:Twenty recreational runners ran on a treadmill at 3 different speeds(2.5...     

COVID-19 vaccination produces exercise-responsive SARS-CoV-2 specific T-cells regardless of infection history

Background:The mobilization and redistribution of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) specific T-cells and neutralizing antibodies(nAbs) during exercise is purported to increase immune surveillance and protect against severe coronavirus disease 2019(COVID-19).We sought to determine if COVID-19 vaccination would elicit exercise-responsive SARS-CoV-2 T-cells and transiently alter nAb titers.Methods:Eighteen healthy participants completed a 20-min bout of graded cycling exer...     

The great catastrophe: causes of the Permo-Triassic marine mass extinctionOA

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the cr...     

Revisiting non-linear Thomson scattering with metamaterialsOA

<正>Non-linear optics is a branch of optics that studies the intriguing and sometimes unexpected ways in which light and matter interact at high intensities, when the polarization density does not respond linearly to the electric field of the light. The pursuit of the perfect non-linear optical material has been ongoing ever since the pioneering experiment on second harmonic generation carried out by Franken in 1961 [1]. Indeed,     

热带钢轧机过程控制新技术

新技术的极用产生了更完美的过程控制技术。这与有效的研究与开发手段结合,成为提高质量、生产率和革新的基础。现代技术的快速和智能化的应用对钢铁工业面临的新的挑战作出了回应。