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《中国科学院院刊(英文版)》2012,26(3):194-195
According to an announcement released by the US National Academy of Sciences (NAS) on May 1, 2012,two outstanding scientists from China including physicist ZHANG Jie and chemist Vivian Wing Wah Yam, both 相似文献
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史蒂芬·霍金 (S .W .Hawking)是 2 0世纪具有很强国际声誉的理论物理学家之一 ,这位伟人在科学理论的认识上具有独到的见解 :对物理理论持典型的朴素证伪主义的观点 ;在物理学统一上 ,谨慎而乐观地相信存在一种完整的统一理论 ;而且 ,“实在”在某种意义上以理论为前提。 相似文献
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Helmut Gernsheim 《Endeavour》1977,1(1):18-22
This year marks the centenary of the death of W. H. Fox Talbot, the inventor of the negative/positive process of photography. This article reviews his contribution to the development of photography in relation to that of other pioneers, notably Niépce, Daguerre, and Archer. It also considers the consequences for the development of photography in Britain of Talbot's strict adherence to his patent rights. 相似文献
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本文为独叶草形态学研究的一部分,主要报道其根状茎结构的初步观察结果。根状茎的初
生结构的基本图案类似一般多年生草本植物的根状茎。但其维管束连接成简状,缺乏髓射线,
以后产生的次生维管组织中亦缺乏明显的射线。木质部的导管主要为梯纹加厚。梯纹导管的分
子的穿孔板呈水平的和不同程度的倾斜状的,水平的和一部分倾斜状的穿孔板上只具有单个
大穿孔,而另一些倾斜状的穿孔板上,呈一种复穿孔到单穿孔的过渡形式。参照Bailey(1956)
指出的管状分子的演化是不可逆的观点,联系到毛茛科植物一般具有单穿孔的导管,应属于一种原始的结构特征。独叶草的营养叶,鳞片叶和芽苞叶都具有单叶隙,前者具四个叶迹,后两
者都具有一个双重性的叶迹。参照前人的看法,联系独叶草的叶,花和导管分子中的一些原始性状推测,可能如Foster(1960,1961)曾指出的,在三叶隙和多叶隙占多数的毛莨科中,独叶草的单叶隙可能是一种原始的形态。 相似文献
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本文报道独叶草 Kingdoinia uniflora 的花、果实和种子的形态结构规律。 花的各部分
多而无定数，呈螺旋状排列。花被片的脉序呈开放的二叉分枝，可分三类。雄蕊分能育和不
育两类，维管束单一，后者顶端的凹沟内具蜜腺，前者的花粉囊呈侧向-外向着生。心皮分化
为三部分，子房具柄，含1枚横生胚珠。开花时，心皮不完全闭合，属半开放型，近似黄连属(Coptis)植物。聚合瘦果，种子1枚，胚处于原胚期，胚乳丰富。文中还讨论了有关形态演化问题。 相似文献
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The present paper is an attempt to throw some light on two Composite genera,
Cavea W. W. Smith et Small and Nannoglottis Maxim., of which the generic features
and the systematic position were heretofore rather badly known.
Cavea, a monotypic genus based upon Saussurea salwinensis Drumm., was described
by W. W. Smith and Small as monocious. From the ample material now in our com-
mand, it is found that the genus is either monocious and dioecious, the capitula in the
latter case being homogamous. The individuals exclusively provided with sterile flowers
are usually smaller in size, sometimes even stemless. Such repartition of sexes was
known in the subtribe Plucheinae (tribe Inuleae), to which W. W. Smith and Small were
correct to ascribe their genus.
Nannoglottis was considered by Maximovicz as un abnormal genus of the tribe
Inuleae, having heterogamous capitula with one series of peripheric fertile ligulate pistil-
late flowers. Having examined the type specimen of N. carpesioices Maxim. and the ex-
tensive collection from Kansu and Tsinghai, we incline to say that the genetic characters
as discerned by Maximovicz are doubtlessly due to his inaccurate observation. The
flowers of Nannoglottis are in fact trimorphous, of which the pistillate ones are 2-3-
seriate, the outer being shortly ligulate and the inner, short-tubulate with truncate apex.
Handel-Mazzetti, much later, indicated that, in another species, the pistillate flowers are
2-3-seriate, but no mention was made about the inner tubulate pistillate flowers.
Franchet, appearing to be unware of Maximovicz's genus, founded his Stereosanthus
Franch. and considered it as a genus intermediate between the tribes Inuleae and Sene-
cioneae. The genus was misinterpreted by Franchet as having dimorphous flowers, the
pistillate ones being all ligulate. Curious enough, one of the major generic features, viz.,
the presence of inner tubulate pistillate flowers, was neglected by all early botanists and
was first recognized by Handel-Mazzetti fourty years later.
However, Handel-Mazzetti was still unacquainted with the characters of Nannoglot-
tis and proposed therefore his new genus Vierhapperia Hand.-Mzt. on the reason that the
flowers are trimorphous. Moreover, he compared his genus with Conyza L. and Erigeron
L. of the tribe Astereae, but the characters marked by him appear not to be different
from those of Nannoglottis.
From the above morphological comparaison, it is evident that Nannoglottis and two
other genera in question possess in common important characters in the general appea-
rance, the flower-forms and the structure of achenes and pappus. The differences in the
disposition of involucral bracts and the length of ligules are criteria good for separating
species, but can hardly be regarded as sufficient for generic delimitation. Moreover,
these three genera are almost similar in their geographical distribution. These points are
adequate to warrant that Stereosanthus and Vierhapperia are in reality congeneric with
Nannoglottis.
Nannoglottis appears to have been correctly placed by Hoffmann in the subtribe
Senecioninae (tribe Senecioneae) though in that subtribe it finds no close relatives. On
account of the outstanding characters of the genus, a further study of its systematic posi-
tion is required.
The present paper is brought to close by a tentative scheme of classification of the
genus so amplified, of which two sections, namely, sect. Stenolepis Ling et Y. L. Chen
(Stereosanthus Franch., p. p. min.) and sect. Nannoglottis (Stereosanthus Franch., p. p.maxim.; Vierhapperia Hand.-Mzt.), altogether including 9 species, are being proposed. 相似文献
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发现卧龙乌头Aconitum wolongense W．T. Wang的模式实际上包含两种植物，即毛果甘青乌头A．
tanguticum (Maxim．)Stapf．var．trichocarpum Hand.-Mazz．和展毛大渡乌头A．franchetii Fin.et Gagnep．var．villosum W．T. Wang，故将该种予以归并。 相似文献
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奇点问题是以广义相对论为基本理论框架的现代宇宙学所面临的自身无法克服的重大疑难问题。霍金的虚时间的数学处理方法可以避免奇点的出现，并很可能使描述极早期宇宙的量子效应与描述整个宇宙演化的广义相对论效应协调。本文从霍金时间概念的变革、虚时间的物理意义和哲学意义三方面研讨了虚时间问题，并提了一些作者独到的新见解。 相似文献
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根据对新宁楼梯草Elatostema xinningense W.T.Wang模式标本的研究，结合在新宁楼梯草模式产地湖南省新宁县紫云山的野外调查，将新宁楼梯草降级并组合为对叶楼梯草E.sinense H.Schr⒐ter的变种。 相似文献
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Polystichum adungense ching et Fraser-Jenkins is described as new from N. Bur-
ma and S. W. China 相似文献
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郭金彬 《科学技术与辩证法》2003,20(1):55-57
瓦托夫斯基把科学哲学描绘成是一种理解科学理解的事业。本文通过对概念和概念框架的阐释和发挥 ,对科学道德进行了理论上的研究。这是将科学道德作为科学哲学的内容进行研究的尝试。 相似文献
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