Subatomic particleIn physics, a subatomic particle is a particle smaller than an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles (for example, a proton, neutron, or meson), or an elementary particle, which is not composed of other particles (for example, an electron, photon, or muon). Particle physics and nuclear physics study these particles and how they interact.
Elementary particleIn particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. The Standard Model presently recognizes seventeen distinct particles, twelve fermions and five bosons. As a consequence of flavor and color combinations and antimatter, the fermions and bosons are known to have 48 and 13 variations, respectively. Among the 61 elementary particles embraced by the Standard Model number electrons and other leptons, quarks, and the fundamental bosons.
Tobler's second law of geographyThe second law of geography, according to Waldo Tobler, is "the phenomenon external to a geographic area of interest affects what goes on inside." This is an extension of his first. He first published it in 1999 in reply to a paper titled "Linear pycnophylactic reallocation comment on a paper by D. Martin" and then again in response to criticism of his first law of geography titled "On the First Law of Geography: A Reply." Much of this criticism was centered on the question of if laws were meaningful in geography or any of the social sciences.
Geography of ChinaChina has great physical diversity. The eastern plains and southern coasts of the country consist of fertile lowlands and foothills. They are the location of most of China's agricultural output and human population. The southern areas of the country (south of the Yangtze River) consist of hilly and mountainous terrain. The west and north of the country are dominated by sunken basins (such as the Gobi and the Taklamakan), rolling plateaus, and towering massifs.
Yellow RiverThe Yellow River is the second-longest river in China, after the Yangtze River, and the sixth-longest river system in Earth at the estimated length of . Originating at an elevation above 15,000 feet (4,600 metres) in the Bayan Har Mountains, it empties into the Bohai Sea. The Yellow River's basin was the birthplace of several ancient civilizations. The yellow sediments were carried downstream from the Loess Plateau. There are frequent devastating floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fields.
ZhongyuanZhongyuan (), the Central Plain(s), also known as Zhongtu (, lit. 'central land') and Zhongzhou (, lit. 'central region'), commonly refers to the part of the North China Plain surrounding the lower and middle reaches of the Yellow River, centered on the region between Luoyang and Kaifeng. It has been perceived as the birthplace of the Chinese civilization. Historically, the Huaxia people viewed Zhongyuan as 'the center of the world'. Human activities in the Zhongyuan region can be traced back to the Palaeolithic period.
