共查询到20条相似文献，搜索用时 31 毫秒
1.
世界发展情势及解决"一带一路"问题的需要,催促我们要升级"一带一路",考虑2.0版。"一带一路"的2.0版较之于1.0版有三大超越:时间上,不是回到历史,而是走出历史;空间上,从经营欧亚大舞台到世界大格局,开创欧亚大陆时代2.0——陆海联通,海洋时代2.0——深海时代、北极、南美;自身发展上,从互联互通到万物互联——从"天地人"到"天地人海空网",秉承人机交互、天地一体,万物互联。开创21世纪人类新文明,引领新型全球化:(1)包容性全球化——让全球化无死角;(2)南方型全球化——从要外援到要投资;(3)联动型全球化——南北联动、陆海联动,打造人类命运共同体。 相似文献
2.
陈介 《中国科学院研究生院学报》1983,21(4):416-422
In this paper, the present writer has discussed the lemurian intercontinental discontinuous distribution of the genus Medinilla of Melastomataceae between Tropical Asia and Tropical Africa. It appears to be that the genus was first brought to Eurasia continent from Africa continent as a result of Indian Plate drift. Therefore we conjecture that the genus probably occurred in Upper Cretaceous and its birthplace is probably in the southern part of Gondwanaland. In addition, we have reduced the genus Pseudodissochaeta M. P. Nayar published in 1969, because in this taxon the extra-ovarial chambers may go down to the middle or to the base of the ovary, as in other genera of Melastomataceae. Besides, no differences in pollen have been found between the taxon and the genus Medinilla. 相似文献
3.
亚洲内陆是北半球最大、最广阔的中纬度干旱区,且不同于世界上分布于副热带高压控制下的干旱区。现今的亚洲中纬度干旱区深居内陆,远离各大洋的水汽来源。亚洲中纬度干旱区究竟如何形成?历经了怎样的干旱化过程?其形成演化的动力机制是什么?这些一直是悬而未决的问题。事实上,亚洲中纬度干旱区发展成今天所见的干旱荒漠,并不是短时间内实现的,而是经历了漫长的阶段性演化进程,是在新生代以来印度、阿拉伯、非洲板块与欧亚大陆的碰撞,青藏高原的隆升,新特提斯海的退却以及新生代全球气候变冷与海平面下降等区域和全球要素共同作用下,从半湿润—半干旱—干旱—极端干旱渐进演化而来。历经了始新世的半湿润气候,渐新世的半湿润-半干旱气候和中新世末期以来的干旱-极端干旱气候。 相似文献
4.
方振富 《中国科学院研究生院学报》1987,25(4):307-313
1. The distribution of Salix species among the continents. There are about
526 species of Salix in the world, most of which are distributed in the Northern Hemisphere
with only a few species in the Southern Hemisphere. In Asia, there are about 375 species, mak-
ing up 71.29 percent of the total in the world, including 328 endemics; in Europe, about 114
species, 21.67 percent with 73 endemics; in North America, about 91 species, 17.3 percent with
71 endemics; in Africa, about 8 species, 1.5 percent, with 6 endemics. Only one species occurs
in South America. Asia, Europe and North America have 8 species in common (excluding 4
cultivated species). There are 34 common species between Asia and Europe, 14 both between
Europe and North America and between Asia and North America, 2 between Asia and Africa.
Acording to the Continental Drift Theory, the natural circumstances which promoted speciation
and protected newly originated and old species were created by the orogenic movement of the
Himalayas in the middle and late Tertiary. Besides, the air temperature was a little higher in
Asia than in Europe and North America (except its west part) and the dominant glaciers were
mountainous in Asia during the glacial epoch in the Quaternary Period. Then willows of Eu-
rope moved southwards to Asia. During the interglacial period they moved in opposite direc-
tion. Such a to-and-fro willow migration between Asia and Europe and between and North
America occurred so often that it resulted in the diversity of willow species in Asia. Those
species of willows common among the continents belong to the Arctic flora.
2. The multistaminal willows are of the primitive group in Salix. Asia has 28 species of
multistaminal willows, but Europe has only one which is also found in Asia. These 28 species
are divided into two groups, “northern type” and “southern type”, according to morphology of
the ovary. The boundary between the two forms in distribution is at 40°N. The multistami-
nal willows from south Asia, Africa and South America are very similar to each other and
may have mutually communicated between these continents in the Middle or Late Cretaceous
Period. The southern type willows in south Asia are similar to the North American multista-
minal willows but a few species. The Asian southern type willows spreaded all over the conti-
nents of Europe, Asia and North America through the communication between them before the
Quaternany Period. Nevertheless, it is possible that the willows growing in North America
immigranted through the middle America from South America. The Asian northern type mul-
tistaminal willows may have originated during the ice period.
The multistaminal willows are more closed to populars in features of sexual organs. They
are more primitive than the willows with 1-3 stamens and the most primitive ones in the ge-
nus.
3. The center of origin and development of willows Based on the above discussion it is re-
asonable to say that the region between 20°-40°N in East Asia is the center of the origin and
differentiation of multistaminal willows. It covers Southern and Southwestern China and nor-
thern Indo-China Pennisula. 相似文献
5.
6.
新疆在中国与中南亚区域经济合作中的战略地位与作用 总被引：2，自引：0，他引：2
自古以来,新疆在中国的经济社会发展战略中处于特别重要的位置。无论是从地缘政治角度考虑,还是从地缘经济角度考虑,新疆与中南亚区域经济整合趋势是不可避免的。环新疆经济圈概念的提出,在一定程度上,更加明确了中国新疆参与中南亚区域经济合作的必然性和可行性。可以预见,21世纪的新疆将成为沟通中国与中亚、南亚、西亚乃至欧洲的中介纽带,成为中国西部地区经济循环与协作的"催化剂"和"推进器",成为欧亚大陆的又一国际经贸中心,从而为"大中华经济圈"在世界东方的崛起做出历史性的贡献。本文在环新疆经济圈概念背景下,深入分析了新疆在中国与中南亚区域经济合作中的战略地位和作用。 相似文献
7.
第四纪是以大冰期为标志的最新地质历史时期。这个大冰期的基本特征是轨道尺度的冰期-间冰期交替及亚轨道尺度的冰阶-间冰阶变化。现在是比较温暖的间冰期,冰川只覆盖陆地面积的10%。而在冰期最盛时,冰川覆盖全球陆地面积的30%,冻土扩展,气候干旱,风沙盛行,海平面降低130—150 m,植被向低纬度收缩10o以上,垂直带谱下移1 000 m以上。冰期天文理论成功解释了冰期-间冰期循环周期问题,但还存在诸多挑战。第四纪也是古人类向现代人发展的时期。古人类诞生于东非,约200万年前曾向欧亚大陆有限扩散,但一直到了末次间冰期才大规模扩散;尤其在随后的末次冰期中,人类更是借助于大陆桥扩散到美洲和澳洲。新仙女木事件后,气候变暖,人类进入细石器时代并逐渐过渡到农业社会。工业革命开始,人类发展深刻影响到了地球的自然进程,导致全球变暖,预示着一个"人类纪"的到来。 相似文献
8.
羌塘与拉萨地块处于青藏高原的核心位置。青藏高原北羌塘及拉萨地块的年代学及古地磁学研究表明,北羌塘地块在距今约3亿年前位于南半球(21.9o±4.7oS)冈瓦纳大陆附近,因而不支持北羌塘地块来自北方劳亚大陆。北羌塘随后开始其持续的北向漂移过程,在约2.1亿年前到达当前纬度位置(34oN),形象地表明其是一只"冈瓦纳大陆的早飞鸟"。拉萨地块从冈瓦纳大陆裂离后的漂移演化史则与北羌塘地块差别明显。自晚古生代—中生代(石炭纪—三叠纪)拉萨地块从冈瓦纳大陆北缘裂离后,其运动学演化过程更显得"犹豫不决"。最新的古地磁研究表明拉萨地块自冈瓦纳大陆裂离后并未显示出明显的快速北向漂移趋势,而是呈现出较为慢速的漂移,直到距今约1.8亿年前(早侏罗世)到达位于南半球赤道附近(3.7o±3.4oS),随后与北面的羌塘地块在晚侏罗世首先从东部发生碰撞,随后于早白垩世时期两个地块完成拼贴。之后的印度次大陆快速向北漂移并在早新生代(距今6 500万年前)发生印度-亚洲大陆碰撞,继而对新生代时期欧亚大陆地形地貌格局产生了深远影响。 相似文献
9.
论胡桃科植物的地理分布 总被引：1，自引：0，他引：1
路安民 《中国科学院研究生院学报》1982,20(3):257-274
The present paper aims to discuss the geog raphical distribution of the Juglandaceae
on the basis of unity of the phylogeny and the process of dispersal in the plants.
The paper is divided into the following three parts:
1. The systematic positions and the distribution patterns of nine living genera in
the family Juglandaceae (namely, Engelhardia, Oreomunnea, Alfaroa, Pterocarya, Cyclo-
carya, Juglans, Carya, Annamocarya and Platycarya) are briefly discussed. The evolu-
tional relationships between the different genera of the Juglandaceae are elucidated. The
fossil distribution and the geological date of the plant groups are reviewed. Through
the analysis for the geographical distribution of the Juglandaceous genera, the distribu-
tion patterns may be divided as follows:
A. The tropical distribution pattern
a. The genera of tropical Asia distribution: Engelhardia, Annamocarya.
b. The genera of tropical Central America distribution: Oreomunnea, Alfaroa.
B. The temperate distribution pattern
c. The genus of disjunct distribution between Western Asia and Eastern Asia:
Pterocarya.
d. The genus of disjunct distribution between Eurasia and America: Juglans.
e. The genus of disjunct distribution between Eastern Asia and North America:
Carya.
f. The genera whose distribution is confined to Eastern Asia: Cyclocarya, Platy-
carya.
2. The distribution of species
According to Takhtajan’s view point of phytochoria, the number of species in every
region are counted. It has shown clearily that the Eastern Asian Region and the Coti-
nental South-east Asian Region are most abundant in number of genera and species. Of
the 71 living species, 53 are regional endemic elements, namely 74.6% of the total species.
The author is of the opinion that most endemic species in Eurasia are of old endemic
nature and in America of new endimic nature. There are now 7 genera and 28 species
in China, whose south-western and central parts are most abundant in species, with Pro-
vince Yunnan being richest in genera and species.
3. Discussions of the distribution patterns of the Juglandaceae
A. The centre of floristic region
B. The centre of floristic regions is determined by the following two principles: a.
A large number of species concentrate in a district, namely the centre of the majority;
b. Species of a district can reflect the main stages of the systematic evolution of the
Juglandaceae, namely the centre of diversity. It has shown clearly that the southern
part of Eastern Asian region and the northern part of Continental South-east Asian
Region (i.c. Southern China and Northern Indo-China) are the main distribution centre
of the Juglandaceae, while the southern part of Sonora Region and Caribbean Region
(i.c. South-western U.S.A., Mexico and Central America) are the secondary distribution
centre.
As far as fossil records goes, it has shown that in Tertiary period the Juglanda-
ceae were widely distributed in northern Eurasia and North America, growing not only
in Europe and the Caucasus but also as far as in Greenland and Alaska. It may be
considered that the Juglandaceae might be originated from Laurasia. According to
the analysis of distribution pattern for living primitive genus, for example, Engelhar-
dia, South-western China and Northern Indo-China may be the birthplace of the most
primitive Juglandaceous plants. It also can be seen that the primitive genera and the
primitive sections of every genus in the Juglandaceae have mostly distributed in the
tropics or subtropics. At the same time, according to the analysis of morphological cha-
racters, such as naked buds in the primitive taxa of this family, it is considered that
this character has relationship with the living conditions of their ancestors. All the
evidence seems to show that the Juglandaceae are of forest origin in the tropical moun-
tains having seasonal drying period.
B. The time of the origin
The geological times of fossil records are analyzed. It is concluded that the origin
of the Juglandaceae dates back at least as early as the Cretaceous period.
C. The routes of despersal
After the emergence of the Juglandaceous plant on earth, it had first developed and
dispersed in Southern China and Indo-China. Under conditions of the stable tempera-
ture and humidity in North Hemisphere during the period of its origin and development,
the Juglandaceous plants had rapidly developed and distributed in Eurasia and dis-
persed to North America by two routes: Europe-Greenland-North America route and
Asia-Bering Land-bridge-North America route. From Central America it later reached
South America.
D. The formaation of the modern distribution pattern and reasons for this forma-
tion.
According to the fossil records, the formation of two disjunct areas was not due to
the origin of synchronous development, nor to the parallel evolution in the two con-
tinents of Eurasia and America, nor can it be interpreted as due to result of transmis-
sive function. The modern distribution pattern has developed as a result of the tectonic
movement and of the climatic change after the Tertiary period. Because of the con-
tinental drift, the Eurasian Continent was separated from the North American Conti-
nent, it had formed a disjunction between Eurasia and North America. Especially, under
the glaciation during the Late Tertiary and Quaternary Periods, the continents in Eu-
rasia and North America were covered by ice sheet with the exception of “plant refuges”, most plants in the area were destroyed, but the southern part of Eastern Asia
remained practically intact and most of the plants including the Juglandaceae were
preserved from destruction by ice and thence became a main centre of survival in the
North Hemisphere, likewise, there is another centre of survival in the same latitude in
North America and Central America.
E. Finally, the probable evolutionary relationships of the genera of the Juglanda-ceae is presented by the dendrogram in the text. 相似文献
10.
学科服务是学科馆员借助图书馆的资源优势和技术手段为用户提供个性化服务的过程,发现服务贯穿于学科服务的整个过程中,是实现学科服务的有效途径。从学科服务的概念以及发展背景出发,论述发现服务的内涵并提出对发现服务新的理解,分析发现服务与学科服务的关系,最后从6个方面探讨发现服务在学科服务中的应用。 相似文献
11.
本文报道了团藻目、壳衣藻科、异形藻属一新种——扁球异形藻。此种从非洲的土壤标本中分离
获得。营养细胞(囊壳、原生质体)与已知的其它8个种有明显的不同。生活史的培养观察发现有性生殖为异配，这是此属未曾被描述的一个特征。 相似文献
12.
Stolberg M 《Isis; an international review devoted to the history of science and its cultural influences》2003,94(2):274-299
Based on a wide range of Latin and vernacular sources, this essay reexamines Thomas Laqueur's and Londa Schiebinger's influential claim that the idea of incommensurable anatomical difference between the sexes was "invented" in the eighteenth century, reflecting, in particular, a need to resort to nature in order to justify female subordination against new ideals of equality and universal rights. It provides ample evidence that already around 1600 many leading physicians, rather than proclaiming a "one-sex model" of female inferiority, insisted on the unique and purposeful features of the female skeleton and the female genital organs and illustrated them visually. The author shares Laqueur's and Schiebinger's assumption that the shift toward incommensurable anatomical difference helped legitimize woman's subordinate position as housewife and mother as naturally given. But around 1600 Enlightenment ideals as yet played no role. Instead, this shift reflected, in particular, contemporary physicians' growing appreciation of personal discovery and innovation, the rise of a specialist gynecology, and new views on marriage and motherhood in the upper classes among whom the physicians lived and whose support they sought. 相似文献
13.
资源发现系统自出现以来提高了用户的检索效率,实现了“资源发现”的图书馆信息服务。本文通过对资源发现系统的简要概述,分析了资源发现系统的研究现状,最后提出了基于用户体验的图书馆资源发现服务体系模型,对模型的功能做了具体的介绍分析,并展望了发现系统未来的发展方向。 相似文献
14.
高蕴璋 《中国科学院研究生院学报》1985,23(4):311-314
Sonneratia, a small genus of Sonneratiaceae, is widely distributed throughout
SE. Asia, E. Africa and N. Australia, extending from 18˚S. to 20˚N. and from 45˚ to
150˚E. In China it occurs only in the Hainan Island. In this paper, two new sections areproposed and six species are recognized, of which one is described as new. 相似文献
15.
非相关文献知识发现方法在航天科技情报研究中的应用分析 总被引：2，自引：0，他引：2
概述了非相关文献知识发现方法的原理以及国内外应用现状,总结了该方法的发现流程以及开发人机交互系统所需要的关键技术,对比分析了非相关文献知识发现方法应用于生物医学领域及航天科技情报研究领域的异同点,人工模拟了用该方法发现新型飞行器隐身技术的知识发现过程,验证了非相关文献知识发现方法用于航天科技情报研究领域的可行性,揭示了规模应用的努力方向. 相似文献
16.
首届诺贝尔物理学奖授予了揭开了现代物理学序幕的X射线的发现,随后的20多年中与X射线密切相关的诺贝尔物理学奖层出不尽。而一个世纪之后空间天文领域的第一个诺贝尔物理学奖于2002年授予了空间X射线天文的突破,由此打开了人类观测宇宙的新窗口。从1962年发现第一个宇宙X射线源至今半个世纪以来,已经有约70个携带天文仪器的空间飞行器(以专用卫星为主)发射运行,极大地促进了人类对于宇宙和基本物理规律的认识。随后2006年的诺贝尔物理学奖授予了"宇宙背景探索者"(COBE)卫星对宇宙微波背景黑体辐射谱的精确测量和观测到空间分布的各向异性。2011年诺贝尔物理学奖授予了宇宙加速膨胀的发现,著名的哈勃空间望远镜对此做出了关键贡献。这样在新世纪空间天文的研究就直接产生了两个诺贝尔物理学奖,并且对第三个起了重要作用,非常类似20世纪初X射线对于诺贝尔物理学奖的作用。文章通过分析这三个以及天文学研究所获得的所有其他诺贝尔物理学奖,发现除了2006年的诺贝尔物理学奖之外,其他所有的获奖成果都和项目最初的科学目标没有关系或者完全相反。与此同时,探讨了重大天文发现的偶然性和必然性,这对于处于快速发展初期的中国空间天文具有很好的借鉴作用。 相似文献
17.
Stothers RB 《Isis; an international review devoted to the history of science and its cultural influences》2004,95(2):220-238
Zoological data and a growing mythology contributed to ancient Western knowledge about large serpents. Yet little modern attention has been paid to the sources, transmission, and receipt in the early Middle Ages of the ancients' information concerning "dragons" and "sea serpents." Real animals--primarily pythons and whales--lie behind the ancient stories. Other animals, conflations of different animals, simple misunderstandings, and willful exaggerations are found to account for the fanciful embellishments, but primitive myths played no significant role in this process during classical times. The expedition of Alexander the Great into India (327-325 B.C.) and the Bagradas River incident in North Africa (256 B.C.) had enormous repercussions on the development of serpent lore. Credible evidence is found for the presence of ancient populations of pythons living along the North African coast west of Egypt and along the coast of the Arabian Sea between the Indus River and the Strait of Hormuz--places where they no longer exist today. The maximum sizes of ancient pythons may have been greater than those of today's specimens. 相似文献
18.
全球能源消费的空间差异及影响因素分析 总被引：1，自引：0，他引：1
选取全球主要国家和地区的能源系统为研究对象,对它们能源消费的规模、结构与效率在空间上的差异进行了分析,之后,采用递阶偏最小二乘(Hi_PLS)模型对能源消费量的主要影响因素进行了辨析,结果表明:①能源消费总量主要集中在北半球或北美、欧亚大陆及亚洲。人均能耗较高的国家则主要集中在油气资源丰富的区域或经济发达区;②结构方面,中东四国油气所占比例受其油气资源禀赋影响非常显著,它们除油气外的其它能耗几乎为0;③效率方面,能耗效率较高的国家主要分布在中南美、欧洲、欧亚大陆及亚太地区,而北美、中东和非洲地区的国家能耗效率则较低;④全球尺度,对能源消费量增长最重要的影响因素为交通业与信息产业的活动(包括基建),其次为医疗业及其它一般意义上的经济活动,最后就是人们投入研发以及从事农业等的活动。人口的自然增长及其结构因素与人们从事教育的活动对能源消费量增长的促进作用不大。据此,提出了一些减缓全球能源消耗,促进各国向低碳清洁的可持续发展模式转变的对策建议,供决策者参考。 相似文献
19.
《中国科学院院刊(英文版)》2008,22(4)
Renzi Cave, the mysterious relic of a population of hominids located in Fanchang County, Anhui Province in eastern China, has gained much spotlight because of its fascinating age, 2 million years. This age suggests that this unknown population might have been the earliest arrival of human beings from Africa, pushing it to the forefront of a big controversy concerning early hominid evolution. 相似文献
20.
本文根据植物类群的系统发育和地理分布统一的原理，讨论了獐牙菜属植物的起源、散布和分
布区的形成。獐牙菜属包括11组16系154种，间断分布在亚洲、欧洲、北美洲和非洲。中国西南部-
喜马拉雅地区汇集了大多数种类、不同演化水平的类群以及形形色色的特有类群，成为该属的多样化
中心和多度中心。该属的原始类群和外类群也集中分布在中国西南山地，极有可能是该属的起源地。该
属的分布区类型中出现了各式的间断分布，根据有该属植物分布的大陆间及大陆与岛屿间分离和连接
的时间推测，该属的起源时间至少不会晚于晚白垩纪，也许更早，可追溯到中白垩纪。通过分类群间亲
缘关系和现代分布分析，显示出该属植物从起源地向周围和一定方向散布，形成了三个主要散布途径。在散布过程中植物本身也发生演化和就地特化，形成新的类群。 相似文献