Carbon compounds in Apollo 11 lunar samples

Are they entrapped solar wind particles, meteoritic or cometary contributions, remnants of a primordial atmosphere or products of the degassing of the Moon ?     

科学:永无止境的迷宫--谈人类对物质结构的认识

通过人类对物质结构认识的发展简史以及粒子物理的重大进展，说明科学是类似于永无止境的迷宫，不可能走向终极。     

受空气浮力影响的称重实验

物体的质量和重量是否与运动速度有关?是否与带电状态有关?为什么陀螺旋转起来后"重量"会变轻?为什么电容器充电后"重量"会变轻?为什么气球充电后会向上飘?实验物体体积增加,导致空气的浮力增加,是产生称重变化的原因。物体的质量和重量与运动速度无关,与带电状态基本无关。     

Exploring complex networks

The study of networks pervades all of science, from neurobiology to statistical physics. The most basic issues are structural: how does one characterize the wiring diagram of a food web or the Internet or the metabolic network of the bacterium Escherichia coli? Are there any unifying principles underlying their topology? From the perspective of nonlinear dynamics, we would also like to understand how an enormous network of interacting dynamical systems-be they neurons, power stations or lasers-will behave collectively, given their individual dynamics and coupling architecture. Researchers are only now beginning to unravel the structure and dynamics of complex networks.     

重新评价马克·吐温的代表作——《汤姆·索耶历险记》和《哈克贝里·费恩历险记》

马克·吐温,这位在美国文学史上开一代创作先河的小说家,为后人留下了20多篇不朽佳作。其中,令人惊讶的是:在他全部作品中,两部描写少年历险故事的著作——《汤姆·索耶历险记》和《哈克贝里·费恩历险记》,始终处于最突出的位置,并一直被中外学者公推为其代表作。于是我们不得不深思这样一个问题,作为美国文坛杰出代表人物之一的马克·吐温为什么选择了儿童的角色,而又把他们塑造得空前成功?纵观文学界对马克·吐温作品及其人物形象的有关研究成果和论述,似乎都不能够圆满地答复这个问题。     

The emerging conceptual framework of evolutionary developmental biology

Over the last twenty years, there has been rapid growth of a new approach to understanding the evolution of organismic form. This evolutionary developmental biology, or 'evo-devo', is focused on the developmental genetic machinery that lies behind embryological phenotypes, which were all that could be studied in the past. Are there any general concepts emerging from this new approach, and if so, how do they impact on the conceptual structure of traditional evolutionary biology? In providing answers to these questions, this review assesses whether evo-devo is merely filling in some missing details, or whether it will cause a large-scale change in our thinking about the evolutionary process.     

Dinosaurian growth patterns and rapid avian growth rates

Did dinosaurs grow in a manner similar to extant reptiles, mammals or birds, or were they unique? Are rapid avian growth rates an innovation unique to birds, or were they inherited from dinosaurian precursors? We quantified growth rates for a group of dinosaurs spanning the phylogenetic and size diversity for the clade and used regression analysis to characterize the results. Here we show that dinosaurs exhibited sigmoidal growth curves similar to those of other vertebrates, but had unique growth rates with respect to body mass. All dinosaurs grew at accelerated rates relative to the primitive condition seen in extant reptiles. Small dinosaurs grew at moderately rapid rates, similar to those of marsupials, but large species attained rates comparable to those of eutherian mammals and precocial birds. Growth in giant sauropods was similar to that of whales of comparable size. Non-avian dinosaurs did not attain rates like those of altricial birds. Avian growth rates were attained in a stepwise fashion after birds diverged from theropod ancestors in the Jurassic period.     

性别与女权主义--探讨女性文学的一个误区

女权主义者关注着女性在男权窠臼下的生存境况,出于对男权的本能拒斥而排斥男性.可是,男人就一定是男权的吗?男人就一定没有女权主义思想吗?女权与女人,男权与男人,是完全对等的吗?基于这些思考,写下此文,试探讨女权的误区.     

一部"另类"的月亮天文学论著——评《开普勒之梦》

伽利略的《对话》和《开普勒之梦》都对同一个问题进行过讨论:月亮是否和地球一样,也存在有生命的物种?但它们不同于此前一些哲学家们的纯思辨性讨论,而是力图从各自的月亮观测结果出发,做出合乎逻辑的设想和解释。望远镜的使用在这里无疑起到了重要作用。《开普勒之梦》作为一本天文学著作中的"另类"之作,在后来某些时候被看作是科幻小说的先驱之作。     

On Some Tips For English Learning

English is more and more important nowadays.A great number of people begin to learn English in order to be able to use it freely at work,study and learn from other countries.How can you learn English well? How do you improve your speaking? How do you improve your listening? Are there any best and quickest methods to learn English? In my humble opinoin,writing more,reading more and listening more are the most effective way or even the only way to improve your English.     

广义华南弧

在华南弧的范围内,除了山系呈弧形分布外,水系、盆地、海岸线也是弧形的,作者对此称之为广义华南弧.     

企业因经营消费不属于消费者

企业因经营消费是否属于消费者,是否应受我国《消费者权益保护法》的保护,这是被人们普遍忽视但却又应是不得不重视的问题。在消费法律关系中,企业不能作为消费者,其消费行为与经营者不构成消费法律关系,其因经营消费与经营者之间产生的纠纷不应适用《消费者权益保护法》。在消费纠纷中,正确认定消费者并正确适用《消费者权益保护法》,有利于指导司法审判工作。     

The spatial arrangement of cones in the primate fovea.

The retinae of Old World primates contain three classes of light-sensitive cone, which exhibit peak absorption in different spectral regions. But how are the different types of cone arranged in the hexagonal mosaic of the fovea? This question has often been answered with artists' impressions, but never with direct measurements. Staining for antibodies specific to the short-wave photopigment has revealed a sparse, semiregular array of cones; but nothing is known about the arrangement of the more numerous long- and middle-wave cones. Are they randomly distributed, with chance aggregations of one type, as Hartridge postulated in these columns nearly 50 years ago? Or do they exhibit a regular alteration, recalling the systematic mosaics seen in some non-mammalian species? Or, conversely, is there positive clumping of particular cone types, as might be expected if local patches of cones were descended from a single precursor cell? We have made direct microspectrophotometric measurements of patches of foveal retina from Old World monkeys, and report here that the distribution of long- and middle-wave cones is locally random. These two cone types are present in almost equal numbers, and not in the ratio of 2:1 that has been postulated for the human fovea.     

直径为3的GS图

研究了直径为３的ＧＳ图的性质。提出了一个非Ｉ－ＧＳ图的构造方法，并证明了由此方法可构造出无穷多个非Ｉ－ＧＳ图，从而解决了Ｐｈｉｌｉｐ　Ｌａｕｆｅｒ提出的下列两个问题：（１）除了已知的两个非Ｉ－ＧＳ图，是否还有其他非Ｉ－ＧＳ图；（２）非Ｉ－ＧＳ图是否为有限个。     

关于逻辑可修正性及相关问题的若干思考

逻辑真理是可错的吗?逻辑是可修正的吗?这些问题因为奎因的系统论述而备受关注,引发了国内外学者的热烈讨论和长期的争议。由于逻辑本被公认的普遍适用性和逻辑真理在逻辑系统中所居的特殊地位,对这些问题的不同回答对逻辑学甚至其他亲缘学科会带来不同的影响。通过梳理评判各家之言后认为,逻辑是可修正的,但逻辑真理是不可错的。     

N体问题中心构型的数学定义

关于N体问题中心构型的定义,有文字定义与数学定义2种.它们是等价的吗?以N体问题的平面正N边形中心构型为例,分析文字定义与数学定义的区别,并由此给出N体问题中心构型更合理的数学定义.     

基于药品本体的信息检索系统研究

随着互联网的普及和Web资源的日益丰富,从网上获取基于药品本体的信息成为人们常用的方式,但用户在检索信息时经常会出现找不到或者查不准的情况。针对这样的问题,提出了一种基于本体的信息检索系统,并将相似度等算法融合其中,从而大大提高了查询的效果。     

控制生物遗传和进化的转座因子

本文简述近代对控制生物遗传和进化的转座因子的研究动态.着重比较转座因子在高等和低等生物中具有极其相似的遗传效应.借以阐明它在生物遗传与进化中所起的可能作用,它与人类染色体异常所引起的某些恶性肿瘤有关.     

大学生基础代谢率的调查研究

<正> 前言基础代谢(basal metabolism)是人体正常觉醒状态下维持生命活动所必须的最低限度的能量代谢,通常以每小时每平方米体表面积所散发的热量来表示,故也称基础代谢率(basal metabolic rate,BMR)。它是个体间进行比较的标准,也是临床上衡量机体能量代谢是否正常及诊断某些疾病的指标之一。关于国人的基础代谢,解放前后均有不少研究,但因测量方法不同,对象和人数不一,因而结论各异。目前,国内所有生理学教材引用的均是吴襄等1943年发表的数据。随着时代的推移,社会的变迁,人民生活的改善,国人的基础代谢率是否发生变化已成为值得探讨的问题。     

"审美意识形态"辩——兼论中国当代历史语境中的文学本质问题

近年来,对“审美意识形态”能否用来表述文学本质这一问题,学界争议很大。根据逻辑学上对本质的界定原则,摆在我们面前的问题有三:文学是不是意识形态?文学与其它意识形态之间的种差是不是审美?审美和意识形态能不能连缀在一起来述说文学的本质?而对这些问题的探讨,均不能脱离具体的历史语境。经过分析论证,研究者提出,在今日中国,“审美意识形态”无论从逻辑层面上还是从历史层面上,都是一个站得住脚的命题,可以用来界定文学的本质属性并成为当代文学理论研究的逻辑起点。坚持文学的“审美意识形态”本质,可以在确立和维护文学自身独立地位的同时,又将文学活动和人类解放这一总目标联系起来,从而使文学研究获得更加坚实的根据和更加广阔的视界。