Fractions with numerator less than denominator are called true fractions. The true score is less than 1. Fractions with numerator greater than denominator or numerator equal to denominator are called false fractions. False score is greater than or equal to 1.
What parts can the earth be divided into? How to divide the interior of the earth can be roughly divided into three parts: crust, mantle and core.
How to divide:
There is a layered structure of concentric spheres in the earth, and the material composition and physical properties of each layer are changing. The interior of the earth cannot be observed directly, so most of the knowledge about the interior of the earth is obtained indirectly. For example, according to the known mass of the earth in astronomy and the shape and size of the earth obtained from geodesy, it can be inferred that the average density of the earth is 5.5g/cm? However, the density of facestock is less than 2.7 g/cm? ; Therefore, it can be inferred that the density of substances in the earth is higher than 5.5g/cm? According to meteorites can be divided into stone meteorites and iron meteorites, and because the earth has obvious endogenous magnetic field, it can be inferred that there is an iron core inside the earth. According to various signs of seismic wave propagation in the earth, it is proved that the earth can be roughly divided into three parts: crust, mantle and core.
Structural characteristics of each layer:
Crust: The outermost layer of the earth's spherical structure. The thickness of continental crust is generally 35 ~ 45km, and the thickness of Himalayan crust can reach 70km and 80km. In 2009, Mohorovicic confirmed the existence of the lower crust interface according to the travel time of the recent earthquake. Below this interface, the velocity of P-wave earthquake suddenly increased from an average of 5.6 km/s to 7.8 km/s, and this interface was later called Moho surface. Continental crust is generally divided into upper crust and lower crust. The upper crust is hard, which is mainly stressed and prone to earthquakes, while the lower crust is soft. The ocean crust is very thin, generally only one layer, even thinner than the continental crust.
Mantle: the middle layer between the crust and the core. The average thickness is over 2800 kilometers. 1914.b. The depth of the interface between the core and the mantle measured by Gutenberg according to the travel time of seismic waves is 2900 kilometers, which is quite accurate. It is only 15km away from the newly calculated value. The mantle is divided into upper mantle (more than 350 kilometers deep) and lower mantle. There is a low velocity layer of seismic waves in the upper mantle, and the relatively hard top of the upper mantle is above the low velocity layer. Usually, the top of the upper mantle and the crust are collectively called lithosphere. The global lithospheric plate constitutes the outermost structure of the earth. The tectonic movement of the earth's surface is mainly carried out in the lithosphere. According to the study of crustal equilibrium, there is a material layer under the lithosphere, which is weak and allows slow deformation and horizontal flow. In 2004, Baler called this material layer the asthenosphere. The concept of asthenosphere and the concept of low-velocity mantle in seismology seem to refer to the same object, and many people equate them.
Core: the core of the earth, mainly composed of iron and nickel, with a radius of 3480 kilometers. 1936. According to the journey of P-wave earthquake through the core, Lyman proposed that there is also an interface in the core, which divides the core into two parts: the outer core and the inner core. Because the outer core can't let shear waves pass through, it is inferred that the material state of the outer core is liquid.
How are fans classified? What are the categories? Fan is a driven fluid machine, which relies on the input mechanical energy to increase gas pressure and exhaust gas.
Fan classification:
Fans can be divided into several types according to the materials used, such as iron shell fans (ordinary fans), glass fiber reinforced plastic fans, plastic fans, aluminum fans, stainless steel fans and so on.
According to the direction of airflow, fans can be divided into centrifugal, axial, oblique (mixed) and cross-flow types.
Fans can also be divided into single-stage, double-stage or multi-stage booster fans according to the pressurization form. For example, 4-72 is a single-stage booster fan, and the high-order fan is a multi-stage booster fan.
Fans can be divided into axial flow fans, mixed flow fans, roof ventilation fans, air conditioning fans and so on.
Fans can be divided into low-pressure fans, medium-pressure fans and high-pressure fans according to pressure.
According to the outlet pressure (boost), it is divided into: ventilator (≤1.5000 Pa), blower (1.535000 Pa) and compressor (≥ 350000 Pa). The above information is provided by Shoupu Electromechanical Company.
In terms of industry, what kinds of photography can be divided into? Documentary photography, landscape photography, portrait photography (including all snapshots with a single group as the main body, such as wedding dresses, personal photography and children's photography. There are crosses with documentaries), commercial photography (photo studios and photo studios basically have everything, and there are crosses with portraits. There are also shooting of various products. There are also elements of creative photography. ), news photography (all the above categories overlap, in fact, they are mixed together. ), creative photography (mainly playing with light and shadow, B-door exposure, etc. ), in fact, all kinds of photography types overlap, and the specific and simple classification is not good, so it can only be distinguished relatively.
According to the supported CPU types, what kinds of motherboards can be divided into? This classification is a bit too much. According to the current manufacturers, it is divided into INTER and AMD.
But every once in a while, manufacturers will change the CPUZ array or packaging technology, so some old motherboards can't support it.
Now the mainstream is inter 775, but it is divided into 65 nm and 45 nm.
AMD is AM2 and am2+
According to the content of communication, what kinds of advertisements can be divided into? According to the content of communication, advertisements can be divided into introductory advertisements, suggestive advertisements, persuasive advertisements and comparative advertisements.
1. Introductory advertisements refer to traditional advertisements that directly introduce the contents of goods and services.
2. Prompt advertisements refer to advertisements that strengthen consumers' understanding and impression of the goods they are used to buying and using, remind consumers not to forget the trademarks, brands and characteristics of the goods, and * * * repeat purchases to consolidate the original market share, attract late users to buy products, and guide consumers to form a stable and long-term habit demand. It is an advertising target implemented in line with the product life cycle entering maturity and recession.
3. Persuasive advertisement is a kind of advertisement aimed at persuasion and also a kind of competitive advertisement. Starting from the immediate interests of consumers, enterprises tell consumers the uniqueness of this brand of goods relative to other brands, change consumers' views, form consumers' special preferences for their own products or services, and then decide to choose their own products or services.
4, comparative advertising, English is, sometimes translated into comparative advertising, competitive advertising. The basic meaning of comparative advertising is that advertisers compare their own companies, products or services with those of competitors in the same industry through advertising. One of the most prominent features of comparative advertising is that advertisers compare their products or services with those of similar competitors in their advertisements, so as to highlight the characteristics, quality or quality that their products or services are superior to or different from those of competitors.
What kinds of soil can be divided into? The classification of soil is not sand, clay and loam, which can be seen as follows: Soil _ Baidu Encyclopedia.
:baike.baidu./view/26545.htm
What kinds of street dance can be divided into? According to the types of movements, street dance can be divided into two categories: street dance and break dance. Broken: It is a highly skilled sports dance, which requires dancers to have high strength, flexibility and coordination. Teenagers who dance this type of dance are called B-Boy/B-Girl.
Hip-Hop: Dance-style hip-hop, which has many styles, such as Poping, Locking, Electric, Turbo, House and so on. They don't need higher skills such as breaking, but they need more coordination and sense of dance, as well as flexibility and control of their limbs.
There is also a saying that hip-hop is collectively referred to as Hip-Hop, including two categories-old shoot and New Shool. Old Shool dances include lock (lock dance), Poping (mechanical dance), break (break dance), Wave (electric current), etc., while New Shool is generally "gentle", without much foot movements, only adding a lot of head and hand movements, paying attention to the rhythm of the upper body. In the rhythm of the same period, the new school appears more fluent and advocates natural expression, while the music rhythm of the old school is more intensive.
In China, street dance is currently divided into fitness street dance and popular street dance. Hip-hop in the gym is called fitness hip-hop, which combines the most basic and simple content covered by popular hip-hop with the part beneficial to physical and mental development.
What kinds of garbage can be divided into? 1 recyclables;
2. Hazardous waste;
3 meals of kitchen waste;
4 Other rubbish.
1. Recyclable: garbage with high recycling value that can enter the waste recycling channel;
2. harmful waste: garbage containing toxic and harmful chemicals; The main treatment methods of hazardous waste are safe landfill and incineration.
3. Kitchen waste: food waste and peels produced in the kitchen; The main treatment methods of kitchen waste are composting and making feed.
4. Other garbage: the general term for all garbage except recyclable garbage, harmful waste garbage and kitchen waste. The main disposal methods of other garbage: the combustible part is burned to generate electricity, and the nonflammable part is sanitary landfilled.