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HF DF
HF, Hf or hf can refer to: Arts and entertainment * HammerFall, a Swedish power metal band * Hard-Fi, an English indie rock band * ''Star Trek: Hidden Frontier'', a long-running Star Trek fan-fiction series * Hi-hat with foot, part of a drum kit Business *Hlutafélag (hf.), a form of limited liability company in Iceland * Hapag-Lloyd Flug, a German airline (former Airline_codes#IATA_airline_designator, IATA code) doing business as TUIfly * Air Côte d'Ivoire, an Ivorian airline (IATA code) * Hedge fund Education * Higher Preparatory Examination (HF) (''Højere Forberedelseseksamen''), a Danish examination programme * ''Heraldo Filipino'', the student newspaper of De La Salle University-Dasmariñas, Cavite, Philippines * Homewood-Flossmoor High School, Flossmoor, Illinois Organizations * Humanity First, an international charitable organisation, which focuses on immediate disaster response and long-term development * Health trust (''Helseforetak''), a Norwegian hospital enterprise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HammerFall
HammerFall is a Swedish power metal band from Gothenburg. The band was formed in 1993 by ex- Ceremonial Oath guitarist Oscar Dronjak. They have released thirteen studio albums. History Early days (1993–1996) HammerFall was formed when guitarist Oscar Dronjak quit Ceremonial Oath and invited Jesper Strömblad (from Ceremonial Oath and In Flames) to join him as a drummer in a new musical project he had been contemplating for some time. Dronjak had already composed the song "Steel Meets Steel," which was later included on HammerFall's debut album. Dronjak and Strömblad were later joined by lead guitarist Niklas Sundin, bassist Johan Larsson, and vocalist Mikael Stanne. When Niklas Sundin and Johan Larsson left HammerFall the following year, Glenn Ljungström (then guitarist of In Flames) and Fredrik Larsson (bassist of the former Swedish death metal band Dispatched), replaced them. All five members played in other bands at the time. Dronjak and Larsson played in '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holstein Friesian Cattle
The Holstein Friesian is an international breed or group of breeds of dairy cattle. It originated in Frisia, stretching from the Dutch province of North Holland to the German state of Schleswig-Holstein. It is the dominant breed in industrial dairy farming worldwide, and is found in more than 160 countries. It is known by many names, among them Holstein, Friesian and Black and White. With the growth of the New World, a demand for milk developed in North America and South America, and dairy breeders in those regions at first imported their livestock from the Netherlands. However, after about 8,800 Friesians ( black pied German cows) had been imported, Europe stopped exporting dairy animals due to disease problems. Today, the breed is used for milk in the north of Europe, and for meat in the south of Europe. After 1945, European cattle breeding and dairy products became increasingly confined to certain regions due to the development of national infrastructure. This change led to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinz Field
Acrisure Stadium, formerly (and still colloquially) known as Heinz Field, is a football stadium located in the North Shore neighborhood of Pittsburgh, Pennsylvania. It primarily serves as the home of the Pittsburgh Steelers of the National Football League (NFL) and the Pittsburgh Panthers of the NCAA Division I Football Bowl Subdivision in the Atlantic Coast Conference (ACC). The stadium opened in 2001 as Heinz Field, following the controlled implosion of the teams' previous home, Three Rivers Stadium. In 2021, the owners of the Heinz name, now owned by Kraft Heinz declined to renew the stadium's naming rights. The City of Pittsburgh green-lit Acrisure's bid to purchase the rights in 2022. Funded in conjunction with PNC Park and the David L. Lawrence Convention Center, the $281 million (equivalent to $ million in ) stadium stands along the Ohio River, on the North Side of Pittsburgh in the North Shore neighborhood. The stadium was designed with the city's history of steel p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Rules Football Positions
In the sport of Australian rules football, each of the eighteen players in a team is assigned to a particular named position on the field of play. These positions describe both the player's main role and by implication their location on the ground. As the game has evolved, tactics and team formations have changed, and the names of the positions and the duties involved have evolved too. There are 18 positions in Australian rules football, not including four (sometimes 6–8) interchange players who may replace another player on the ground at any time during play. The fluid nature of the modern game means the positions in football are not as formally defined as in sports such as rugby or American football. Even so, most players will play in a limited range of positions throughout their career, as each position requires a particular set of skills. Footballers who are able to play comfortably in numerous positions are referred to as utility players. In an effort to maintain tradit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hilbert Function
In commutative algebra, the Hilbert function, the Hilbert polynomial, and the Hilbert series of a graded commutative algebra finitely generated over a field are three strongly related notions which measure the growth of the dimension of the homogeneous components of the algebra. These notions have been extended to filtered algebras, and graded or filtered modules over these algebras, as well as to coherent sheaves over projective schemes. The typical situations where these notions are used are the following: * The quotient by a homogeneous ideal of a multivariate polynomial ring, graded by the total degree. * The quotient by an ideal of a multivariate polynomial ring, filtered by the total degree. * The filtration of a local ring by the powers of its maximal ideal. In this case the Hilbert polynomial is called the Hilbert–Samuel polynomial. The Hilbert series of an algebra or a module is a special case of the Hilbert–Poincaré series of a graded vector space. The Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Frequency
High frequency (HF) is the ITU designation for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters). Frequencies immediately below HF are denoted '' medium frequency'' (MF), while the next band of higher frequencies is known as the '' very high frequency'' (VHF) band. The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called ''shortwave radio''. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or "skywave" propagation – these frequencies can be used for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations (3.95–25.8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicon Focus
Helicon Focus is a proprietary commercial digital image processing tool, first released in 2003, developed and published by Helicon Soft Limited. Like programs such as CombineZ or Zerene Stacker, Helicon Focus is designed to blend the focused areas of several partially focused digital photographs to increase the depth of field (DOF) in an image. Overview Helicon Focus can be used to increase DOF in any situation, though its primary uses are in macro photography, landscape photography and photo-microscopy. In macro photography, the DOF is often very small. To increase it, Helicon Focus is capable of merging several differently focused images together to create one image where the subject is entirely in focus. Features * Automatic adjustments during stacking * "Dust map" for removing black points from the resulting images * Supports most common file types, including RAW, TIFF, JPEG, JPEG 2000, and BMP * Can add text and a scale bar * 3D stack visualization and Wavefront .obj exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicon Filter
Helicon Filter, also referred to as Helicon, Filter, or as HF, was a proprietary commercial and shareware photo editing software program for Microsoft Windows, similar to such programs as Adobe Photoshop and GIMP, developed and published by Helicon Soft Ltd. Unlike these other programs, Helicon Filter is designed primarily to edit and improve existing photos and not for graphics creation. Helicon Filter's interface also differs from other programs in that compact toolbars and menus containing editing tools are replaced with labeled "filter" tabs, each tab containing labeled edit options specific to a single aspect of the picture. Although some editors used to Photoshop-style programs may initially find this layout unfamiliar and unlike the standard toolbar layout, beginners and those who don't recognize the standard icons generally find this very helpful for getting through the editing process. Overview Helicon Filter, formally Helicon NoiseFilter, was introduced in August, 200 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Handsfree
Handsfree is an adjective describing equipment that can be used without the use of hands (for example via voice commands) or, in a wider sense, equipment which needs only limited use of hands, or for which the controls are positioned so that the hand can occupy themselves with another task (such as driving) without needing to hunt far afield for the controls. Devices that are typically used for handsfree communication use Bluetooth as its wireless technology. They still require a smartphone or other device to initiate a call. These devices include Bluetooth headsets, hands-free car kits (HFCK), and personal navigation devices (PND). Originally introduced as optional features connected by a wire to smartphones or other communication devices, they now generally are available with wireless technology. Bluetooth handsfree options are now also easily found in any high end automotive as part of the vehicle's stereo system, or in after market stereo system units. This option utilizes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrofluoric Acid
Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colorless, acidic and highly corrosive. A common concentration is 49% (48–52%) but there are also stronger solutions (e.g. 70%) and pure HF has a boiling point near room temperature. It is used to make most organofluorine compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon). Elemental fluorine is produced from it. It is commonly used to etch glass and silicon wafers. Uses Production of organofluorine compounds The principal use of hydrofluoric acid is in organofluorine chemistry. Many organofluorine compounds are prepared using HF as the fluorine source, including Teflon, fluoropolymers, fluorocarbons, and refrigerants such as freon. Many pharmaceuticals contain fluorine. Production of inorganic fluorides Most high-volume inorganic fluoride compounds are prepared from hydrofluoric acid. Foremost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Fluoride
Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers such as polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils near room temperature, a much higher temperature than other hydrogen halides. Hydrogen fluoride is an extremely dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. The gas can also cause blindness by rapid destruction of the corneas. History In 1771 Carl Wilhelm Scheele prepared the aqueous solution, hydrofluoric acid in large quantities, although hydrofluoric acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hartree–Fock Method
In computational physics and chemistry, the Hartree–Fock (HF) method is a method of approximation for the determination of the wave function and the energy of a quantum many-body system in a stationary state. The method is named after Douglas Hartree and Vladimir Fock. The Hartree–Fock method often assumes that the exact ''N''-body wave function of the system can be approximated by a single Slater determinant (in the case where the particles are fermions) or by a single permanent (in the case of bosons) of ''N'' spin-orbitals. By invoking the variational method, one can derive a set of ''N''-coupled equations for the ''N'' spin orbitals. A solution of these equations yields the Hartree–Fock wave function and energy of the system. Hartree–Fock approximation is an instance of mean-field theory, where neglecting higher-order fluctuations in order parameter allows interaction terms to be replaced with quadratic terms, obtaining exactly solvable Hamiltonians. Especially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
