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Vinylon
Vinylon, also known as Vinalon (more common in Korean sources), is a synthetic fiber produced from reaction between polyvinyl alcohol (PVA) fiber and formaldehyde. Chemically it is polyvinyl formal (PVF). Vinylon was first developed in Japan in 1939 by , Ri Sung-gi, and H. Kawakami. In North Korea, Ri Sung-gi found a route to produce PVA from domestic anthracite (black coal) and limestone as raw materials. Trial production began in 1954 and in 1961 the massive "Vinylon City" was built in Hamhung, North Korea. Vinylon's widespread usage in North Korea is often pointed to as an example of the implementation of the ''Juche'' philosophy, and it is known as the ''Juche'' fiber. PVF, in fiber form, is a useful thermoplastic resin on its own, most commonly used as electric wire insulation. Applications Vinylon is the national fiber of North Korea and is used for the majority of textiles, outstripping fiber such as cotton or nylon, which is produced only in small amounts in North K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamhung
Hamhŭng (''Hamhŭng-si''; ) is North Korea's List of cities in North Korea, second-most populous city, the capital of South Hamgyong, South Hamgyŏng Province and the 16th largest city in the Korea, Korean Peninsula. Located in the southern part of the South Hamgyong province, Hamhung is the main and most populous metropolitan area in the province. Hamhung was Urban planning, centrally planned and built by the government of North Korea. Administrative divisions Hamhŭng is Administrative divisions of North Korea#Second-level divisions, divided into 7 ''guyŏk'' (wards): Geography Hamhŭng is on the left branch of the Chongchon River, Ch'ŏngch'ŏn River, on the eastern part of the Hamhŭng plain (), in South Hamgyŏng Province, northeast North Korea. Its highest point is Mount Tonghŭng, which is high. Climate Hamhung has a humid continental climate (Köppen climate classification: ''Dwa''), with warm, humid summers, and moderately cold, dry winters. Being located by the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyvinyl Alcohol
Polyvinyl alcohol (PVOH, PVA, or PVAl) is a water- soluble synthetic polymer. It has the idealized formula H2CH(OH)sub>''n''. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) adhesive formulations, in a variety of coatings, and 3D printing. It is colourless (white) and odorless. It is commonly supplied as beads or as solutions in water. Without an externally added crosslinking agent, PVA solution can be gelled through repeated freezing-thawing, yielding highly strong, ultrapure, biocompatible hydrogels which have been used for a variety of applications such as vascular stents, cartilages, contact lenses, etc. Although polyvinyl alcohol is often referred to by the acronym PVA, more generally PVA refers to polyvinyl acetate, which is commonly used as a wood adhesive and sealer. Uses PVA is used in a variety of medical applications because of its biocompatibility, low tendency for protein adhesion, and low to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toshiko MacAdam
Toshiko MacAdam (born Toshiko Horiuchi) is a Japanese textile artist based in Bridgetown, Nova Scotia, Canada. She is best known for her work with large-scale textile structures, especially "textile playgrounds" for children, brightly colored net-like structures of crocheted and knotted nylon. Life and career Toshiko Horiuchi MacAdam is a leading fibre artist in Canada and Japan, using knitting, crochet, and knot making techniques to create her work. Currently, her work focuses on creating large, interactive textile environments. MacAdam was born in Japan in 1940 but soon moved to Japanese-occupied Manchuria with her family during World War II. When the Soviet Union took over the area in 1945, MacAdam and her family were forced to flee and eventually returned to Japan. Later, MacAdam attended the Tama Fine Art Institute in Japan and went on to study in the Cranbrook Academy of Art in Michigan, where she received her masters of fine arts degree. After graduating, MacAdam worked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juche
''Juche'', officially the ''Juche'' idea, is a component of Ideology of the Workers' Party of Korea#Kimilsungism–Kimjongilism, Kimilsungism–Kimjongilism, the state ideology of North Korea and the official ideology of the Workers' Party of Korea. North Korean sources attribute its conceptualization to Kim Il Sung, the country's founder and first leader. ''Juche'' was originally regarded as a variant of Marxism–Leninism until Kim Jong Il, Kim Il Sung's son and successor, declared it a distinct ideology in the 1970s. Kim Jong Il further developed ''Juche'' in the 1980s and 1990s by making ideological breaks from Marxism–Leninism and increasing the importance of his father's ideas. ''Juche'' incorporates the historical materialist ideas of Marxism–Leninism but also strongly emphasizes the individual, the nation state, and national sovereignty. ''Juche'' posits that a country will prosper once it has become self-reliant by achieving political, economic, and military indep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Korea - Myohyang Mountains (5015252383)
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is related to the Old High German ''nord'', both descending from the Proto-Indo-European unit *''ner-'', meaning "left; below" as north is to left when facing the rising sun. Similarly, the other cardinal directions are also related to the sun's position. The Latin word ''borealis'' comes from the Greek ''boreas'' "north wind, north" which, according to Ovid, was personified as the wind-god Boreas, the father of Calais and Zetes. ''Septentrionalis'' is from ''septentriones'', "the seven plow oxen", a name of ''Ursa Major''. The Greek ἀρκτικός (''arktikós'') is named for the same constellation, and is the source of the English word ''Arctic''. Other languages have other derivations. For example, in Lezgian, ''kefer'' can mean bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetic Acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Historically, vinegar was produced from the third century BC and was likely the first acid to be produced in large quantities. Acetic acid is the second simplest carboxylic acid (after formic acid). It is an important Reagent, chemical reagent and industrial chemical across various fields, used primarily in the production of cellulose acetate for photographic film, polyvinyl acetate for wood Adhesive, glue, and synthetic fibres and fabrics. In households, diluted acetic acid is often used in descaling agents. In the food industry, acetic acid is controlled by the E number, food additive code E260 as an acidity regulator and as a condiment. In biochemistry, the acetyl group, derived from acetic acid, is funda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Acetate
Vinyl acetate is an organic compound with the Chemical formula, formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohol, and other important industrial polymers. Production The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000). The average list price for 2008 was US$1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7%), Chang Chun Group (6%), and LyondellBasell (5%). Vinyl acetate is mainly (80%) polymerized, and the resulting polymer is hydrolyzed to give polyvinvyl alcohol. Preparation Vinyl acetate is the acetate ester of vinyl alcohol. Since vinyl alcohol is highly unstable (with respect to acetaldehyde), the prepara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects. In more straightforward polymerizations, alkenes form polymers through relatively simple radical reactions; in contrast, reactions involving substitution at a carbonyl group require more complex synthesis due to the way in which reactants polymerize. As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and polyvinyl chloride (PVC), which are produced in high tonnages each year due to their usefulnes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetal
In organic chemistry, an acetal is a functional group with the connectivity . Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments not hydrogen. The two R' groups can be equivalent to each other (a "symmetric acetal") or not (a "mixed acetal"). Acetals are formed from and convertible to aldehydes or ketones and have the same oxidation state at the central carbon, but have substantially different chemical stability and reactivity as compared to the analogous carbonyl compounds. The central carbon atom has four bonds to it, and is therefore saturated and has tetrahedral geometry. The term ketal is sometimes used to identify structures associated with ketones (both R groups organic fragments rather than hydrogen) rather than aldehydes and, historically, the term acetal was used specifically for the aldehyde-related cases (having at least one hydrogen in place of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyvinyl Acetate
Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue (a term that may also refer to other types of glues), PVA glue, white glue, carpenter's glue, school glue, or Elmer's Glue in the US, is a widely available adhesive used for porous materials like wood, paper, and cloth. An aliphatic rubbery synthetic polymer with the formula (C4H6O2)''n'', it belongs to the polyvinyl ester family, with the general formula − COOCHCH2��. It is a type of thermoplastic. Properties The degree of polymerization of polyvinyl acetate is typically 100 to 5000, while its ester groups are sensitive to base hydrolysis and slowly convert PVAc into polyvinyl alcohol and acetic acid. The glass transition temperature of polyvinyl acetate is between 30 and 45 °C depending on the molecular weight. PVAc dispersions such as Elmer's Glue-All contain polyvinyl alcohol as a protective colloid. In alkaline conditions, boron compounds such as boric acid or borax cause the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Carbide
Calcium carbide, also known as calcium acetylide, is a chemical compound with the chemical formula of . Its main use industrially is in the production of acetylene and calcium cyanamide. The pure material is colorless, while pieces of technical-grade calcium carbide are grey or brown and consist of about 80–85% of (the rest is CaO ( calcium oxide), ( calcium phosphide), CaS ( calcium sulfide), ( calcium nitride), SiC (silicon carbide), C (carbon), etc.). In the presence of trace moisture, technical-grade calcium carbide emits an unpleasant odor reminiscent of garlic. Applications of calcium carbide include manufacture of acetylene gas, generation of acetylene in carbide lamps, manufacture of chemicals for fertilizer, and steelmaking. Production Calcium carbide is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately . This is an endothermic reaction requiring per mole and high temperatures to drive off the carbon monoxide. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemiacetal
In organic chemistry, a hemiacetal is a functional group the general formula , where is a hydrogen atom or an organic substituent. They generally result from the nucleophilic Addition reaction, addition of an Alcohol (chemistry), alcohol (a compound with at least one hydroxy group) to an aldehyde () or a ketone () under acidic conditions. The addition of an alcohol to a ketone is more commonly referred to as a hemiketal. Common examples of hemiacetals include cyclic Monosaccharide, monosaccharides. Hemiacetals have use as a protecting group and in synthesizing oxygenated heterocycles like Tetrahydrofuran, tetrahydrofurans. Nomenclature According to the IUPAC definition of a hemiacetal, the R1 and R2 groups may or may not be hydrogen. In a hemiketal, both of these R-groups must not be hydrogen. Thus, hemiketals are regarded as a subclass of hemiacetals. The prefix ''hemi,'' meaning half, refers to the one alcohol added to the carbonyl group. This is half of the required alcohols to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
