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Qinling Mountains
The Qinling () or Qin Mountains, formerly known as the Nanshan ("Southern Mountains"), are a major east–west mountain range in southern Shaanxi Province, China. The mountains mark the divide between the drainage basins of the Yangtze and Yellow River systems, providing a natural boundary between North and South China and support a huge variety of plant and wildlife, some of which is found nowhere else on earth. To the north is the densely populated Wei River valley, an ancient center of Chinese civilization. To the south is the Han River valley. To the west is the line of mountains along the northern edge of the Tibetan Plateau. To the east are the lower Funiu and Dabie Mountains, which rise out of the coastal plain. The northern side of the range is prone to hot weather, the rain shadow cast by the physical barrier of the mountains dictating that the land to the north has a semi-arid climate, and is consequently somewhat impoverished in regard to fertility and species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Qin (state)
Qin (, , or ''Ch'in'') was an ancient Chinese state during the Zhou dynasty. It is traditionally dated to 897 BC. The state of Qin originated from a reconquest of western lands that had previously been lost to the Xirong. Its location at the western edge of Chinese civilisation allowed for expansion and development that was not available to its rivals in the North China Plain. After extensive reform during the 4th century BC, Qin emerged as one of the dominant powers among the Seven Warring States. It Qin's wars of unification, unified the seven states of China under Qin Shi Huang in 221 BC. This unification established the Qin dynasty, which, despite its short duration, had a significant influence on later Chinese history. Accordingly, the state of Qin before the Qin dynasty was established is also referred to as the "predynastic Qin" or "proto-Qin". History Founding According to the 2nd-century BC ''Records of the Grand Historian'' by Sima Qian, the state of Qi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral (railway)
A spiral (sometimes called a spiral loop or just loop) is a technique employed by Rail transport, railways to ascend steep hills. A railway spiral rises on a steady curve until it has completed a loop, passing over itself as it gains height, allowing the railway to gain vertical elevation in a relatively short horizontal distance. It is an alternative to a Zig zag (railway), zig-zag, and avoids the need for the trains to stop and reverse direction while ascending. If the train is longer than the length of each loop it may be possible to view it looping above itself. The term "loop" is also often used for a railway that curves sharply and goes back on itself: if the railway crosses itself, then it forms a spiral or helix; otherwise, it forms the much more common Horseshoe curve, horseshoe curve or bend. List of spirals Argentina * Two spirals between Tacuara and Meseta at and on the heritage ''Tren a las Nubes'' section of the Salta–Antofagasta railway part of the General ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadleaf Deciduous Forest
Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These forests are richest and most distinctive in central China and eastern North America, with some other globally distinctive ecoregions in the Himalayas, Western and Central Europe, the southern coast of the Black Sea, Australasia, Southwestern South America and the Russian Far East. Ecology The typical structure of these forests includes four layers. * The uppermost layer is the canopy composed of tall mature trees ranging from high. Below the canopy is the three-layered, shade-tolerant understory that is roughly shorter than the canopy. * The top layer of the understory is the sub-canopy composed of smaller mature trees, saplings, and suppressed juvenile canopy layer trees awaiting an opening in the canopy. * Below the sub-canopy is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yangtze River
The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, in a generally easterly direction to the East China Sea. It is the fifth-largest primary river by discharge volume in the world. Its drainage basin comprises one-fifth of the land area of China, and is home to nearly one-third of the country's population. The Yangtze has played a major role in the history, culture, and economy of China. For thousands of years, the river has been used for water, irrigation, sanitation, transportation, industry, boundary-marking, and war. The Yangtze Delta generates as much as 20% of China's GDP, and the Three Gorges Dam on the Yangtze is the largest hydro-electric power station in the world. In mid-2014, the Chinese government announced it was building a multi-tier transport network, comprising railways, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drainage Divide
A drainage divide, water divide, ridgeline, watershed, water parting or height of land is elevated terrain that separates neighboring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single range of hills or mountains, known as a dividing range. On flat terrain, especially where the ground is marshy, the divide may be difficult to discern. A triple divide is a point, often a summit, where three drainage basins meet. A ''valley floor divide'' is a low drainage divide that runs across a valley, sometimes created by deposition or stream capture. Major divides separating rivers that drain to different seas or oceans are continental divides. The term ''height of land'' is used in Canada and the United States to refer to a drainage divide. It is frequently used in border descriptions, which are set according to the "doctrine of natural boundaries". In glaciated areas it often refers to a low point on a divide where it is po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BioScience
''BioScience'' is a monthly peer-reviewed scientific journal that is published by Oxford University Press on behalf of the American Institute of Biological Sciences. It was established in 1964 and was preceded by the ''AIBS Bulletin'' (1951–1963). The journal publishes literature reviews of current research in biology, as well as essays and discussion sections on education, public policy, history of biology, and theoretical issues. Abstracting and indexing The journal is abstracted and indexed in MEDLINE/ PubMed (1973–1979), the Science Citation Index, Current Contents/Agriculture, Biology & Environmental Sciences, The Zoological Record, and BIOSIS Previews. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecoregion
An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation (largely undefined at this point). Ecoregions are also known as "ecozones" ("ecological zones"), although that term may also refer to biogeographic realms. Three caveats are appropriate for all bio-geographic mapping approaches. Firstly, no single bio-geographic fram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest
A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a Canopy (biology), canopy cover of more than 10 percent, or trees able to reach these thresholds ''in situ''. It does not include land that is predominantly under agricultural or urban use." Using this definition, ''Global Forest Resources Assessment (FRA), Global Forest Resources Assessment 2020'' found that forests covered , or approximately 31 percent of the world's land area in 2020. Forests are the largest Terrestrial ecosystem, terrestrial ecosystems of Earth by area, and are found around the globe. 45 percent of forest land is in the Tropical forest, trop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deciduous
In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, after flowering; and to the shedding of ripe fruit. The antonym of deciduous in the botanical sense is evergreen. Generally, the term "deciduous" means "the dropping of a part that is no longer needed or useful" and the "falling away after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer, deciduous teeth (baby teeth) in some mammals (including humans); or decidua, the uterine lining that sheds off after birth. Botany In botany and horticulture, deciduous plants, including trees, shrubs and herbaceous perennials, are those that lose all of their Leaf, leaves for part of the year. This process is called abscission. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shudao
The Shudao (), or the Road(s) to Shu, is a system of mountain roads linking the Chinese province of Shaanxi with Sichuan (Shu), built and maintained since the 4th century BC. Technical highlights were the gallery roads, consisting of wooden planks erected on wooden or stone beams slotted into holes cut into the sides of cliffs. Geography The roads join three adjacent basins separated and surrounded by high mountains. The northern basin is called Guanzhong ("between the passes"). It is drained by the Yellow River. In ancient times it was the heart of the Qin (state), state of Qin, nowadays it is the central region of Shaanxi. To the south it is bounded by the Qinling Mountains. South of that range is the Hanzhong basin, drained by the Hanshui, Han River, a tributary of the Yangtze. The Hanzhong basin is divided from the Sichuan basin by mountain ranges called the Micang Shan (米倉山/米仓山, ''Mǐcāng Shān'', "Rice Granary Mountains") in the west and Daba Mountains in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Maiji
The Maijishan Grottoes (), formerly romanized as Maichishan, are a series of 194 rock-cut caves cut into the Maijishan hill in Tianshui, Gansu Province, northwest China. They contain over 7,200 Buddhist sculptures and over 1,000 square meters of murals. The name ''Maijishan'' consists of three Chinese words (): ''mai'' () is the generic term for most grains, ''ji'' () means "stack" or "mound", and ''shan'' () means "mountain". ''Maijishan'' is often translated as "wheatstack mountain" or "corn rick mountain". The mountain is formed of purplish red sandstone. Construction of the grottoes began in the Later Qin era (384–417 CE). A team of Chinese archeologists from Beijing conducted the first modern exploration in 1952–53. They devised the numbering system still in use today. Caves #1–50 are on the western cliff face, while caves #51–191 on the eastern cliff face. The grottoes were later photographed by Michael Sullivan and Dominique Darbois, who subsequently published ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
