Graphite
Graphite specimen
General
Category	Native element mineral
Chemical formula	C
Strunz classification	01.CB.05a
Crystal symmetry	Hexagonal dihexagonal dipyramidal H-M symbol: (6/m 2/m 2/m) Space group: P 63/mmc
Unit cell	a = 2.461 Å, c = 6.708 Å; Z = 4
Identification
Color	Iron-black to steel-gray; deep blue in transmitted light
Crystal habit	Tabular, six-sided foliated masses, granular to compacted masses
Crystal system	Hexagonal
Twinning	Present
Cleavage	Basal – perfect on {0001}
Fracture	Flaky, otherwise rough when not on cleavage
Tenacity	Flexible non-elastic, sectile
Mohs scale hardness	1–2
Luster	Metallic, earthy
Streak	Black
Diaphaneity	Opaque, transparent only in extremely thin flakes
Density	2.09–2.23 g/cm3
Optical properties	Uniaxial (–)
Pleochroism	Strong
Solubility	Molten Ni
References	[1][2][3]

The mineral graphite  /ˈɡræfaɪt/ is an allotrope of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω (graphō), "to draw/write",^[4] for its use in pencils, where it is commonly called lead (not to be confused with the metallic element lead). Unlike diamond (another carbon allotrope), graphite is an electrical conductor, a semimetal. It is, consequently, useful in such applications as arc lamp electrodes. Graphite is the most stable form of carbon under standard conditions. Therefore, it is used in thermochemistry as the standard state for defining the heat of formation of carbon compounds. Graphite may be considered the highest grade of coal, just above anthracite and alternatively called meta-anthracite, although it is not normally used as fuel because it is difficult to ignite.

There are three principal types of natural graphite, each occurring in different types of ore deposit:

1. Crystalline flake graphite (or flake graphite for short) occurs as isolated, flat, plate-like particles with hexagonal edges if unbroken and when broken the edges can be irregular or angular;
2. Amorphous graphite occurs as fine particles and is the result of thermal metamorphism of coal, the last stage of coalification, and is sometimes called meta-anthracite. Very fine flake graphite is sometimes called amorphous in the trade;
3. Lump graphite (also called vein graphite) occurs in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular crystalline aggregates, and is probably hydrothermal in origin.

Highly ordered pyrolytic graphite or highly oriented pyrolytic graphite (HOPG) refers to graphite with an angular spread between the graphite sheets of less than 1°. This highest-quality synthetic form is used in scientific research.^[5] The name "graphite fiber" is also sometimes used to refer to carbon fiber or carbon fiber-reinforced polymer.

Occurrence[link]

Graphite output in 2005

Graphite occurs in metamorphic rocks as a result of the reduction of sedimentary carbon compounds during metamorphism. It also occurs in igneous rocks and in meteorites.^[3] Minerals associated with graphite include quartz, calcite, micas and tourmaline. In meteorites it occurs with troilite and silicate minerals.^[3]

According to the United States Geological Survey (USGS), world production of natural graphite in 2008 was 1,110 thousand tonnes (kt), of which the following major exporters are: China (800 kt), India (130 kt), Brazil (76 kt), North Korea (30 kt) and Canada (28 kt). Graphite is not mined in the US, but US production of synthetic graphite in 2007 was 198 kt valued at $1.18 billion. US graphite consumption was 42 kt and 200 kt for natural and synthetic graphite, respectively.^[6]

Properties[link]

Structure[link]

Graphite has a layered, planar structure. In each layer, the carbon atoms are arranged in a hexagonal lattice with separation of 0.142 nm, and the distance between planes is 0.335 nm.^[7] The two known forms of graphite, alpha (hexagonal) and beta (rhombohedral), have very similar physical properties (except that the graphene layers stack slightly differently).^[8] The hexagonal graphite may be either flat or buckled.^[9] The alpha form can be converted to the beta form through mechanical treatment and the beta form reverts to the alpha form when it is heated above 1300 °C.^[10] The layering contributes to its lower density.^{[clarification needed]}

• 

  Scanning tunneling microscope image of graphite surface atoms
• 

  graphite's unit cell
• 

  ball-and-stick model of graphite (2 graphene layers)
• 

  side view of layer stacking
• 

  plane view of layer stacking

Rotating graphite stereogram

Other properties[link]

The acoustic and thermal properties of graphite are highly anisotropic, since phonons propagate very quickly along the tightly-bound planes, but are slower to travel from one plane to another.

Graphite can conduct electricity due to the vast electron delocalization within the carbon layers (a phenomenon called aromaticity). These valence electrons are free to move, so are able to conduct electricity. However, the electricity is primarily conducted within the plane of the layers. The conductive properties of powdered graphite^[11] allowed its use as a semiconductor substitute in early carbon microphones.

Graphite and graphite powder are valued in industrial applications for its self-lubricating and dry lubricating properties. There is a common belief that graphite's lubricating properties are solely due to the loose interlamellar coupling between sheets in the structure.^[12] However, it has been shown that in a vacuum environment (such as in technologies for use in space), graphite is a very poor lubricant. This observation led to the discovery that the lubrication is due to the presence of fluids between the layers, such as air and water, which are naturally adsorbed from the environment. This molecular property is unlike other layered, dry lubricants such as molybdenum disulfide. Recent studies suggest that an effect called superlubricity can also account for graphite's lubricating properties. The use of graphite is limited by its tendency to facilitate pitting corrosion in some stainless steel,^[13][14] and to promote galvanic corrosion between dissimilar metals (due to its electrical conductivity). It is also corrosive to aluminium in the presence of moisture. For this reason, the US Air Force banned its use as a lubricant in aluminium aircraft,^[15] and discouraged its use in aluminium-containing automatic weapons.^[16] Even graphite pencil marks on aluminium parts may facilitate corrosion.^[17] Another high-temperature lubricant, hexagonal boron nitride, has the same molecular structure as graphite. It is sometimes called white graphite, due to its similar properties.

When a large number of crystallographic defects bind these planes together, graphite loses its lubrication properties and becomes what is known as pyrolytic graphite. It is also highly anisotropic, and diamagnetic, thus it will float in mid-air above a strong magnet.If it is made in a fluidized bed at about 1000c – 1300c it is isotropic turbostratic, and is used in blood contacting devices like mechanical heart valves and is called (pyrolytic carbon), and is not diamagnetic. Pyrolytic graphite, and pyrolytic carbon are often confused but are very different materials.^{[citation needed]}

Natural and crystalline graphites are not often used in pure form as structural materials, due to their shear-planes, brittleness and inconsistent mechanical properties.

History of natural graphite use[link]

Graphite was used by the 4th millennium B.C. Marica culture to create a ceramic paint to decorate pottery during the Neolithic Age in southeastern Europe.^[18]

Some time before 1565 (some sources say as early as 1500), an enormous deposit of graphite was discovered on the approach to Grey Knotts from the hamlet of Seathwaite in Borrowdale parish, Cumbria, England, which the locals found very useful for marking sheep.^[19][20] During the reign of Elizabeth 1 (1533–1603), Borrowdale graphite was used as a refractory material to line molds for cannon balls, resulting in rounder, smoother balls that could be fired further, contributing to the growing superiority of the English navy. This particular deposit of graphite was extremely pure and soft, and could easily be broken into sticks. Because of its military importance, this unique mine and its production were strictly controlled by the Crown.

[edit] Other names

Historically, graphite was called blacklead and plumbago.^[21]

Plumbago was commonly used for its massive mineral form. Both of these names arise from confusion with the similar-appearing lead ores, particularly galena. The Latin word for lead is plumbum, which gave its name to both the English term for this grey metallic-sheened mineral and even the leadworts or plumbagos, plants with flowers that resemble this colour.

The term blacklead has usually been applied to a powdered or processed form, where this fine powder then appears as a matte non-metallic black.

Uses of natural graphite[link]

Natural graphite is mostly consumed for refractories, batteries, steelmaking, expanded graphite, brake linings, foundry facings and lubricants.^[6] Graphene, which occurs naturally in graphite, has unique physical properties and might be one of the strongest substances known; however, the process of separating it from graphite will require some technological development before it is economically feasible to use it in industrial processes.

Refractories[link]

This end-use begins before 1900 with the graphite crucible used to hold molten metal; this is now a minor part of refractories. In the mid 1980s, the carbon-magnesite brick became important, and a bit later the alumina-graphite shape. Currently the order of importance is alumina-graphite shapes, carbon-magnesite brick, monolithics (gunning and ramming mixes), and then crucibles.

Crucibles began using very large flake graphite, and carbon-magnesite brick requiring not quite so large flake graphite; for these and others there is now much more flexibility in size of flake required, and amorphous graphite is no longer restricted to low-end refractories. Alumina-graphite shapes are used as continuous casting ware, such as nozzles and troughs, to convey the molten steel from ladle to mold, and carbon magnesite bricks line steel converters and electric arc furnaces to withstand extreme temperatures. Graphite Blocks are also used in parts of blast furnace linings where the high thermal conductivity of the graphite is critical. High-purity monolithics are often used as a continuous furnace lining instead of the carbon-magnesite bricks.

The US and European refractories industry had a crisis in 2000–2003, with an indifferent market for steel and a declining refractory consumption per tonne of steel underlying firm buyouts and many plant closings. Many of the plant closings resulted from the acquisition of Harbison-Walker Refractories by RHI AG some plants had their equipment auctioned off. Since much of the lost capacity was for carbon-magnesite brick, graphite consumption within refractories area moved towards alumina-graphite shapes and monolithics, and away from the brick.The major source of carbon-magnesite brick is now imports from China. Almost all of the above refractories are used to make steel and account for 75% of refractory consumption; the rest is used by a variety of industries, such as cement.

According to the USGS, US natural graphite consumption in refractories was 11,000 tonnes in 2006.^[6]

Batteries[link]

This unreferenced section requires citations to ensure verifiability.

Batteries are the fastest growing end use for graphite. Natural and synthetic graphite are used to construct the anode of all major battery technologies.

The rise of the Li-ion battery has caused great excitement in the graphite industry in recent times. Significantly more graphite than lithium carbonate is needed in a Li-ion batteries – between 5 and 10 times more.

Demand for batteries (primarily nickel-metal-hydride and to a lesser extent Li-ion) caused a surged in graphite demand in the late 1980s and early 1990s – driven by portable electronics such as the walkman and power tools.

The advent of the laptops, mobile phones and the Apple iPad and iPhone products has increased the demand for batteries. But it is electric vehicles that hold the potential to see graphite demand boom. For example, the Li-ion battery in the fully electric Nissan Leaf contains nearly 40 kg of graphite.

Steelmaking[link]

Natural graphite in this end use mostly goes into carbon raising in molten steel, although it can be used to lubricate the dies used to extrude hot steel. Supplying carbon raisers is very competitive, therefore subject to cut-throat pricing from alternatives such as synthetic graphite powder, petroleum coke, and other forms of carbon. A carbon raiser is added to increase the carbon content of the steel to the specified level. An estimate based on USGS US graphite consumption statistics indicates that 10,500 tonnes were used in this fashion in 2005.^[6]

Brake linings[link]

Natural amorphous and fine flake graphite are used in brake linings or brake shoes for heavier (nonautomotive) vehicles, and became important with the need to substitute for asbestos. This use has been important for quite some time, but nonasbestos organic (NAO) compositions are beginning to cost graphite market share. A brake-lining industry shake-out with some plant closings has not helped either, nor has an indifferent automotive market. According to the USGS, US natural graphite consumption in brake linings was 6,510 tonnes in 2005.^[6]

Foundry facings and lubricants[link]

A foundry facing mold wash is a water-based paint of amorphous or fine flake graphite. Painting the inside of a mold with it and letting it dry leaves a fine graphite coat that will ease separation of the object cast after the hot metal has cooled. Graphite lubricants are specialty items for use at very high or very low temperatures, as forging die lubricant, an antiseize agent, a gear lubricant for mining machinery, and to lubricate locks. Having low-grit graphite, or even better no-grit graphite (ultra high purity), is highly desirable. It can be used as a dry powder, in water or oil, or as colloidal graphite (a permanent suspension in a liquid). An estimate based on USGS graphite consumption statistics indicates that 2,200 tonnes was used in this fashion in 2005.^[6]

Pencils[link]

This unreferenced section requires citations to ensure verifiability.

Graphite pencils

The classic end use for graphite which gives graphite its name – "graph" in Latin means to draw.

Today, pencils are still a small but significant market for natural graphite. Around 4% of the 1.1 million tonnes produced in 2011 was used to make pencils. Low-quality amorphous graphite is used, sourced mainly from the south of China.

Other uses[link]

Natural graphite has found uses in zinc-carbon batteries, in electric motor brushes, and various specialized applications. Graphite is also commonly used in the form of powders, and sticks for the purpose of writing or drawing. Graphite of various hardness or softness results in different qualities and tones when used as an artistic medium.^[22]

Speciality grades: Expanded graphite[link]

Expanded graphite is made by immersing natural flake graphite in a bath of chromic acid, then concentrated sulfuric acid, which forces the crystal lattice planes apart, thus expanding the graphite. The expanded graphite can be used to make graphite foil or used directly as "hot top" compound to insulate molten metal in a ladle or red-hot steel ingots and decrease heat loss, or as firestops fitted around a fire door or in sheet metal collars surrounding plastic pipe (during a fire, the graphite expands and chars to resist fire penetration and spread), or to make high-performance gasket material for high-temperature use. After being made into graphite foil, the foil is machined and assembled into the bipolar plates in fuel cells. The foil is made into heat sinks for laptop computers which keeps them cool while saving weight, and is made into a foil laminate that can be used in valve packings or made into gaskets. Old-style packings are now a minor member of this grouping: fine flake graphite in oils or greases for uses requiring heat resistance. A GAN estimate of current US natural graphite consumption in this end use is 7,500 tonnes.^[6]

Speciality grades: Intercalated graphite[link]

Graphite forms intercalation compounds with some metals and small molecules. In these compounds, the host molecule or atom gets "sandwiched" between the graphite layers, resulting in a type of compounds with variable stoichiometry. A prominent example of an intercalation compound is potassium graphite, denoted by the formula KC₈. Graphite intercalation compounds are superconductors. The highest transition temperature (by June 2009) T_c = 11.5 K is achieved in CaC₆ and it further increases under applied pressure (15.1 K at 8 GPa).^[23]

Uses of synthetic graphite[link]

Invention of a process to produce synthetic graphite[link]

A process to make synthetic graphite was invented by Edward Goodrich Acheson (1856–1931). In the mid 1890s, Acheson discovered that overheating carborundum, which he is also credited with discovering, produced almost pure graphite. While studying the effects of high temperature on carborundum, he had found that silicon vaporizes at about 4,150° C (7,500° F), leaving behind graphitic carbon. This graphite was another major discovery for him, and it became extremely valuable and helpful as a lubricant.

The Acheson Graphite Co. was formed in 1899. In 1928 this company was merged with National Carbon Company (now GrafTech International). Acheson also developed a variety of colloidal graphite products including Oildag and Aquadag. These were later manufactured by the Acheson Colloids Co. (now Acheson Industries).

Electrodes[link]

These electrodes carry the electricity that melts scrap iron and steel (and sometimes direct-reduced iron: DRI) in electric arc furnaces, the vast majority of steel furnaces. They are made from petroleum coke after it is mixed with coal tar pitch, extruded and shaped, then baked to carbonize the binder (pitch), and then graphitized by heating it to temperatures approaching 3000 °C, that converts carbon to graphite. They can vary in size up to 11 ft. long and 30 in. in diameter. An increasing proportion of global steel is made using electric arc furnaces, and the electric arc furnace itself is getting more efficient and making more steel per tonne of electrode. An estimate based on USGS data indicates that graphite electrode consumption was 197,000 tonnes in 2005.^[6]

Powder and scrap[link]

The powder is made by heating powdered petroleum coke above the temperature of graphitization, sometimes with minor modifications. The graphite scrap comes from pieces of unusable electrode material (in the manufacturing stage or after use) and lathe turnings, usually after crushing and sizing. Most synthetic graphite powder goes to carbon raising in steel (competing with natural graphite), with some used in batteries and brake linings. According to the USGS, US synthetic graphite powder and scrap production was 95,000 tonnes in 2001 (latest data).^[6]

Neutron moderator[link]

Special grades of synthetic graphite also find use as a matrix and neutron moderator within nuclear reactors. Its low neutron cross-section also recommends it for use in proposed fusion reactors. Care must be taken that reactor-grade graphite is free of neutron absorbing materials such as boron, widely used as the seed electrode in commercial graphite deposition systems—this caused the failure of the Germans' World War II graphite-based nuclear reactors. Since they could not isolate the difficulty they were forced to use far more expensive heavy water moderators. Graphite used for nuclear reactors is often referred to as nuclear graphite.

Other uses[link]

Graphite (carbon) fiber and carbon nanotubes are also used in carbon fiber reinforced plastics, and in heat-resistant composites such as reinforced carbon-carbon (RCC). Commercial structures made from carbon fiber graphite composites include fishing rods, golf club shafts, bicycle frames, sports car body panels, the fuselage of the Boeing 787 Dreamliner and pool cue sticks and have been successfully employed in reinforced concrete, The mechanical properties of carbon fiber graphite-reinforced plastic composites and grey cast iron are strongly influenced by the role of graphite in these materials. In this context, the term "(100%) graphite" is often loosely used to refer to a pure mixture of carbon reinforcement and resin, while the term "composite" is used for composite materials with additional ingredients.^[24]

Graphite has been used in at least three radar absorbent materials. It was mixed with rubber in Sumpf and Schornsteinfeger, which were used on U-boat snorkels to reduce their radar cross section. It was also used in tiles on early F-117 Nighthawks. Modern smokeless powder is coated in graphite to prevent the buildup of static charge.

Graphite mining, beneficiation, and milling[link]

Graphite is mined by both open pit and underground methods. Graphite usually needs beneficiationThis may be carried out by hand-picking the pieces of gangue (rock) and hand-screening the product or by crushing the rock and floating out the graphite. Beneficiation by flotation encounters the difficulty that graphite is very soft and "marks" (coats) the particles of gangue. This makes the "marked" gangue particles float off with the graphite, yielding impure concentrate. There are two ways of obtaining a commercial concentrate or product: repeated regrinding and floating (up to seven times) to purify the concentrate, or by acid leaching (dissolving) the gangue with hydrofluoric acid (for a silicate gangue) or hydrochloric acid (for a carbonate gangue).

In the milling process, the incoming graphite products and concentrates can be ground before being classified (sized or screened), with the coarser flake size fractions (below 8 mesh, 8–20 mesh, 20–50 mesh) carefully preserved, and then the carbon contents are determined. Some standard blends can be prepared from the different fractions, each with a certain flake size distribution and carbon content. Custom blends can also be made for individual customers who want a certain flake size distribution and carbon content. If flake size is unimportant, the concentrate can be ground more freely. Typical end products include a fine powder for use as a slurry in oil drilling and coatings for foundry molds, carbon raiser in the steel industry (Synthetic graphite powder and powdered petroleum coke can also be used as carbon raiser). Environmental impacts from graphite mills consist of air pollution including fine particulate exposure of workers and also soil contamination from powder spillages leading to heavy metals contaminations of soil.

Graphite recycling[link]

The most common way graphite is recycled occurs when synthetic graphite electrodes are either manufactured and pieces are cut off or lathe turnings are discarded, or the electrode (or other) are used all the way down to the electrode holder. A new electrode replaces the old one, but a sizeable piece of the old electrode remains. This is crushed and sized, and the resulting graphite powder is mostly used to raise the carbon content of molten steel. Graphite-containing refractories are sometimes also recycled, but often not because of their graphite: the largest-volume items, such as carbon-magnesite bricks that contain only 15–25% graphite, usually contain too little graphite. However, some recycled carbon-magnesite brick is used as the basis for furnace repair materials, and also crushed carbon-magnesite brick is used in slag conditioners. While crucibles have a high graphite content, the volume of crucibles used and then recycled is very small.

A high-quality flake graphite product that closely resembles natural flake graphite can be made from steelmaking kish. Kish is a large-volume near-molten waste skimmed from the molten iron feed to a basic oxygen furnace, and is a mix of graphite (precipitated out of the supersaturated iron), lime-rich slag, and some iron. The iron is recycled on site, so what is left is a mixture of graphite and slag. The best recovery process uses hydraulic classification (Which utilizes a flow of water to separate minerals by specific gravity: graphite is light and settles nearly last.) to get a 70% graphite rough concentrate. Leaching this concentrate with hydrochloric acid gives a 95% graphite product with a flake size ranging from 10 mesh down.

See also[link]

References[link]

Further reading[link]

• C.Michael Hogan, Marc Papineau et al. (December 18, 1989). Phase I Environmental Site Assessment, Asbury Graphite Mill, 2426–2500 Kirkham Street, Oakland, California, Earth Metrics report 10292.001 (Report). 
• Klein, Cornelis and Cornelius S. Hurlbut, Jr. (1985). Manual of Mineralogy: after Dana (20th ed.). ISBN 0-471-80580-7. 
• Taylor, Harold A. (2000). Graphite. Financial Times Executive Commodity Reports. London: Mining Journal Books ltd.. ISBN 1-84083-332-7. 
• Taylor, Harold A. (2005). Graphite. Industrial Minerals and Rocks (7th ed.). Littleton, CO: AIME-Society of Mining Engineers. ISBN 0-87335-233-5. 

External links[link]

Wikimedia Commons has media related to: Graphite

• Graphite at Minerals.net
• Mineral galleries
• Mindat w/ locations
• giant covalent structures
• The Graphite Page
• Video lecture on the properties of graphite by Prof. M. Heggie, University of Sussex

This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (January 2010)

Im Yoona
Background information
Birth name	임윤아
Also known as	Yoona YoonA, Deer Yoona, Yoon-Ah, Nam Choding, Him Yoona
Born	(1990-05-30) May 30, 1990 (age 22)
Origin	Seoul, South Korea
Genres	K-pop, dance-pop
Occupations	Singer, actress, dancer, model, TV Presenter, TV Host
Years active	2004 (model); 2007-Present (singer & actress)
Labels	SM Entertainment
Associated acts	Girls' Generation SM Town
Website	Official website 150px Signature of Yoona

This article contains Korean text. Without proper rendering support, you may see question marks, boxes, or other symbols instead of Hangul or Hanja.

Im Yoona (Korean: 임윤아; born May 30, 1990), also Im Yun-Ah, is a South Korean idol singer, dancer, actress and promotional model. She is a member and the visual of the girl group, Girls' Generation. She made her debut as an actress in the 2007 drama, 9 Ends, 2 Outs^[1][2] .

Biography[link]

Yoona was born on May 30, 1990, in Seoul, South Korea. She was cast in 2002 SM Entertainment Saturday Open Casting Audition and began to train with the other trainees under SM Entertainment in the areas of acting, singing and dancing. She has trained with SME for 5 years, after which she joined and debuted under Girls' Generation SNSD.

Career[link]

Girls' Generation[link]

Yoona joined SM Saturday Open Casting Audition in 2002, in which she sang WAX's " Please", danced Britney Spears' "Oops..! I did it again " and BoA' "Valenti". Later, she began to train under SM Entertainment in various areas. In 2007, she was chosen as a member of the group Girls' Generation. The 9-member girl group debuted on August 5, 2007.

Acting[link]

YoonA made her debut as an actress in 2007 with the drama 9 Ends, 2 Outs.^[3] In 2008, she acted in the drama Woman of Matchless Beauty before her first leading role in the daily drama You Are My Destiny which she won her important recognitions in acting.^[4] YoonA filmed her 2009 drama Cinderella Man (신데렐라맨) alongside with Kwon Sang-woo.

In 2011, Im was cast in a lead role with Jang Keun Suk in the drama entitled Love Rain. The drama will begin broadcast in 2012 on KBS2. Love Rain is a fantasy drama about fate and how the offspring of a previous ill-fated couple who met in the 1970s, also manage to fall in love with each other. Love Rain will be directed by Yoon Suk Ho with the script by Oh Su Yeon, a pair that also created Autumn in My Heart and Winter Sonata, the latter of which Love Rain is being compared to.

Television[link]

The entertainer was a guest on SBS TV Family Outing which ended February 14, 2010, and a permanent cast member on Family Outing Season 2 with Yoon Sang-hyun, Kim Won-hee, Ji Sang-ryeol, Shin Bong-seon, Jang Dong-Min, Super Junior's Kim Heechul 2AM's Jo Kwon and 2PM's Ok Taecyeon.^[5][6] The program ended its run on July 11, 2010 after 5 months.

On December 24, 2011 she was an MC for 2011 KBS Entertainment Awards together with Shin Dong Yeob & Lee Ji Ae. She was also an MC for 2011 SBS Gayo Daejun together with Song Ji Hyo and Lee Seung Gi.

Promotion[link]

Before her debut with Girls' Generation, Im had been well known in the entertainment industry as she began to film commercials and model for various magazines when she was a trainee with SM Entertainment. Apart from Girls' Generation's commercials, she is currently a model for Clean & Clear, YeJiMin Pad, Innisfree Cosmetics, S-Oil and Eider.

In May 2008, she with fellow members Tiffany, Jessica and TVXQ members had a TV ad for Haptic Motion. Along with her fellow member Sooyoung, she modeled for the '08-09 F/W SFAA Seoul Collection – Lee Joo-Young Fashion Show' at Seoul Hakyohul Exhibition Hall on March 20, 2008.

In April 2010, with fellow members Yuri and Seohyun, along with 2PM members Nichkhun, Taecyeon and Chansung, she filmed a commercial for Everland's Caribbean Bay. The commercial was released in mid-May and is accompanied by the song "Cabi Song.^[7][8]

Im was chosen along with Korean celebrities such as Rain, Kim Hee-seon, Ji Jin-hee, Ha Ji-won, Son Ye-jin, Kim Hyun-joong and Yunho to be the model of Cartier's LOVE collections. Proceeds from the sale of the bracelets will go to the international organization International Vaccine Institute (IVI).

Im released her first solo song "Innisfree Day" on August 30, 2010 for the Eco Handkerchief's promotion of Innisfree Cosmetics.

Discography[link]

• Innisfree Day (Innisfree promotion song)
• Cover of Madonna's "4-Minutes" (ft. Justin Timberlake)
• Cover of Rumble Fish's "Introduce me to a good person"

Filmography[link]

Television drama[link]

Television shows[link]

Music video appearances[link]

MC[link]

TV Commercials / Advertisements[link]

• [2004-2008] Elite Uniform Model
• [2006] Teun Teun English "Follow Me"
• [2006] Sanyo Eneloop Rechargeable Battery
• [2006-2007] Elite (with SS501)
• [2007] Sunkist Lemonade (with Heechul & Kangin)
• [2007] Solar-C Vitamin
• [2008] Elite Uniform (with 2PM)
• [2008-2009] Clean & Clear (with So Eun)
• [2008-2009] YeJiMin
• [2009-2012] Innisfree
• [2010] S-Oil
• [2010] Caribbean Bay (with 2PM)
• [2011-2012] EIDER (with Lee Minho)

Awards[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Im Yoon-Ah

• Im Yoon-Ah at HanCinema

Ryu Hwayoung 류화영 柳花英
Hwayoung at the Cyworld Dream Music Festival in July 2011
Background information
Birth name	Ryu Hwayoung (류화영)
Also known as	Hwayoung (화영)
Born	(1993-04-22) April 22, 1993 (age 19) Gwangju, South Korea[1]
Occupations	Idol, singer
Years active	2010–present
Labels	Core Contents Media, Mnet Media
Associated acts	T-ara

Ryu Hwayoung (Hangul: 류화영; Hanja: 柳花英; born April 22, 1993), better known as simply Hwayoung, is a South Korean idol singer and a member of girl group T-ara.

Biography[link]

1993–2010: Early life[link]

Hwayoung was born on 22 April 1993 in Gwangju, South Korea.^[2] Her twin sister is fellow label-mate, Ryu Hyoyoung, who is a member of Coed School and 5dolls, with a minute's difference between them. Hwayoung is the younger of the two.

2010–present: T-ara[link]

Hwayoung was added into T-ara in July 2010 as their seventh member.^[3] She was scouted after she and her sister made an appearance on SBS's variety show Star King. Both of them were then recruited into Core Contents Media, debuting in T-ara and Coed School respectively.

Discography[link]

References[link]

External links[link]

Hwayoung on Twitter

Donald Sadoway giving a 3.091 lecture on 9 December 2009

Donald Robert Sadoway is the current (as of November 2008^[update]) John F. Elliott Professor of Materials Chemistry at the Massachusetts Institute of Technology. A faculty member in the Department of Materials Science Engineering, he is a noted expert on batteries and has done significant research on how to improve the performance and longevity of portable power sources.^[1]

Background[link]

Born March 7, 1950 in Toronto, Ontario, he did both his undergraduate and graduate studies at the University of Toronto, receiving his PhD in 1977. There he focused his studies on chemical metallurgy.^[2] In 1977, he received a NATO postdoctoral fellowship from the National Research Council of Canada and came to MIT to conduct his postdoctoral research under Julian Szekely. Sadoway joined the MIT faculty in 1978.^[3]

Research[link]

As a researcher, Sadoway has focused on environmental ways to extract metals from their ores, as well as producing more efficient batteries.^[3] His research has often been driven by the desire to reduce the carbon pollution output by various industries.^[2] He is the co-inventor of a solid polymer electrolyte. This material, used in his "sLimcell" has the capability of allowing batteries to offer twice as much power per kilogram as is possible in current lithium ion batteries.^[4]

In August 2006, a team that he led demonstrated the feasibility of extracting iron from its ore through molten oxide electrolysis. When powered exclusively by renewable electricity, this technique has the potential to eliminate the carbon dioxide emissions that are generated through traditional methods.^[5]

In 2009, Sadoway proposed a very low cost molten salt battery based on magnesium and antimony separated by a salt^[6] that could be used in stationary energy storage systems.^[7] Research on this concept is being funded by ARPA-E.^[8] Experimental data showed 69% storage efficiency with good storage capacity and relatively low leakage.^[9]

Teaching[link]

Professor Sadoway teaches 3.091 Introduction to Solid State Chemistry,^[10] one of the largest classes at MIT. Sadoway's animated teaching style is popular with students and freshman enrollment in the course has steadily increased while enrollment in MIT 5.111 and MIT 5.112, the other freshman chemistry offerings at MIT, has declined.

In contrast to much of the Institute's learning and teaching technique, Prof. Sadoway demands that students complete one quiz of memorization, which admittedly is a small percentage (<1%) of students' final grades. He requires that students memorize the Periodic table, saying that he would not accept the reality where an MIT student does not know where to find an element on the table. Clever mnemonics are often used to quickly memorize and subsequently forget the table.

Sadoway refers to exams as "celebrations of learning". His weekly tests are returned in no later than twenty-four hours, his recitation instructors are required to grade quickly in order to provide instant feedback.

In the fall of 2007 the number of students registering for 3.091 reached 570 students, over half the freshman class. The largest lecture hall available on campus seats 566 students, enough to amply house the class. Sadoway much prefers teaching in one of the smaller lecture halls, seating only 450; as such the Institute had to take the unprecedented step of streaming digital video of the lecture into an overflow room to accommodate all the students interested in taking the course.^[11] In contrast, most classes at MIT are relatively small with approximately 60% of classes at MIT having fewer than 20 students.^[12] The popularity of this course has reached outside of the MIT campus as a result of the MIT OpenCourseWare initiative. This is seen in a comment by Bill Gates who told the Seattle Post-Intelligencer "... Everybody should watch chemistry lectures -- they're far better than you think. Don Sadoway, MIT -- best chemistry lessons anywhere. Unbelievable".^[13]

Professor Sadoway's lectures often include the history of science, especially with respect to the Nobel Prize. Sadoway gives out "library assignments" in which he asks students to research Nobel Prize winning papers. He begins his lectures by playing music, which has some connection with the lecture's material. He ends his lectures with five minutes of culturally relevant material, such as automotive exhaust processing or his own work on batteries.

Accolades[link]

He is one of Time's Top 100 Most Influential People in the World in 2012 for his continuing work in improved batteries.^[14]

References[link]