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V404CygLightCurve
V4 or V-4 may refer to: Science and technology * LNER Class V4, a class of British steam locomotives * V4 engine, a V engine with four cylinders in two banks of two cylinders * Visual area V4, in the visual cortex * Klein four-group, in mathematics * ITU-T V.4, a telecommunication recommendation * ATC code V04 ''Diagnostic agents'', a subgroup of the Anatomical Therapeutic Chemical Classification System * The V4 JavaScript engine for QML * V4, one of six precordial leads in electrocardiography * V-4 (rocket launch), first mostly-successful launch of the V-2 rocket Other uses * Visegrád Group, an alliance of four Central European states - Czech Republic, Hungary, Poland and Slovakia * '' Rheinbote'' or V-4, a German World War II four-stage missile * Saint Kitts & Nevis (ITU prefix) * Vieques Air Link (IATA airline code) * V4, a grade (climbing) Many climbing routes have grades for the technical difficulty, and in some cases for the risks, of the route. The first ascent, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LNER Class V4
The London and North Eastern Railway Class V4 was a class of 2-6-2 steam locomotive designed by Sir Nigel Gresley for mixed-traffic use. It was Gresley's last design for the LNER before he died in 1941. The V4s had similarities in their appearance and mechanical layout to the LNER Class V2, V2 "Green Arrow" class. The V2s, introduced some years before, were large and heavy locomotives, with very limited route availability. The V4 was a lightweight alternative, suitable for use over the whole of the LNER network. Features Two locomotives were built at the LNER's Doncaster Works in 1941. The first engine, 3401 ''Bantam Cock'', had a scaled-down version of the Gresley Pacific boiler with a grate area of 28.5 sq ft. Its tractive effort of 27,000 lbs was produced by boiler pressure of 250 Pound-force per square inch, psi and three cylinders of 15-inch diameter. The second locomotive, 3402, incorporated a fully welded steel Firebox (steam engine), firebox and a single thermic syphon f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V4 Engine
A V4 engine is a four-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V engine, V configuration. The V4 engine is less common compared to straight-four engines. However, V4 engines have been used in automobiles, motorcycles, and other applications. Design Some V4 engines have two crankpins that are shared by opposing cylinders. The crankshaft is usually supported by three main bearings in this type of engines. However this arrangement results an uneven firing engine. Split crankpins are preferred for even firing intervals. Compared to the more common inline-four engine layout, a V4 engine is much shorter. Although different V angles can be used, if the two pistons are at a 90° V-angle with shared crankpins, the engine also achieves a perfect Engine balance#Primary and secondary balance, primary balance and offers the additional advantage of better Engine balance#Primary and secondary balance, secondary balance that reduces vibration. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Area V4
The visual cortex of the brain is the area of the cerebral cortex that processes visual perception, visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 (Brodmann area#BA17,V1, V1), Brodmann area 17, or the striate cortex. The extrastriate cortex, extrastriate areas consist of visual areas 2, 3, 4, and 5 (also known as V2, V3, V4, and V5, or Brodmann area 18 and all Brodmann area 19). Both cerebral hemisphere, hemispheres of the brain include a visual cortex; the visual cortex in the left hemisphere receives signals from the right visual field, and the visual cortex in the right hemisphere receives signals from the left visual field. Introduction The primary visual cortex (V1) is loca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klein Four-group
In mathematics, the Klein four-group is an abelian group with four elements, in which each element is Involution (mathematics), self-inverse (composing it with itself produces the identity) and in which composing any two of the three non-identity elements produces the third one. It can be described as the symmetry group of a non-square rectangle (with the three non-identity elements being horizontal reflection, vertical reflection and 180-degree rotation), as the group of bitwise operation, bitwise exclusive or, exclusive-or operations on two-bit binary values, or more abstract algebra, abstractly as \mathbb_2\times\mathbb_2, the Direct product of groups, direct product of two copies of the cyclic group of Order (group theory), order 2 by the Fundamental theorem of finitely generated abelian groups, Fundamental Theorem of Finitely Generated Abelian Groups. It was named ''Vierergruppe'' (, meaning four-group) by Felix Klein in 1884. It is also called the Klein group, and is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITU-T V
The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Communication Technology, such as X.509 for cybersecurity, Y.3172 and Y.3173 for machine learning, and H.264/MPEG-4 AVC for video compression, between its Member States, Private Sector Members, and Academia Members. The World Telecommunication Standardization Assembly (WTSA), the sector's governing conference, convenes every four years. ITU-T has a permanent secretariat called the Telecommunication Standardization Bureau (TSB), which is based at the ITU headquarters in Geneva, Switzerland. The current director of the TSB is Seizo Onoe (of Japan), whose 4-year term commenced on 1 January 2023. Seizo Onoe succeeded Chaesub Lee of South Korea, who was director from 1 January 2015 until 31 December 2022. Primary fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATC Code V04
V04B Urine tests :''Empty group'' V04C Other diagnostic agents V04CA Tests for diabetes :V04CA01 Tolbutamide :V04CA02 Glucose V04CB Tests for fat absorption :V04CB01 Vitamin A concentrates V04CC Tests for bile duct patency :V04CC01 Sorbitol :V04CC02 Magnesium sulfate :V04CC03 Sincalide :V04CC04 Ceruletide V04CD Tests for pituitary function :V04CD01 Metyrapone :V04CD03 Sermorelin :V04CD04 Corticorelin :V04CD05 Somatorelin :V04CD06 Macimorelin V04CE Tests for liver functional capacity :V04CE01 Galactose :V04CE02 Sulfobromophthalein :V04CE03 Methacetin (13C) V04CF Tuberculosis diagnostics :V04CF01 Tuberculin V04CG Tests for gastric secretion :V04CG01 Cation exchange resins :V04CG02 Betazole :V04CG03 Histamine phosphate :V04CG04 Pentagastrin :V04CG05 Methylthioninium chloride :V04CG30 Caffeine and sodium benzoate V04CH Tests for renal function and ureteral injuries :V04CH01 Inulin and other polyfructosans :V04CH02 Indigo carmine :V04CH03 Phenolsulfonphthalein :V04 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JavaScript
JavaScript (), often abbreviated as JS, is a programming language and core technology of the World Wide Web, alongside HTML and CSS. Ninety-nine percent of websites use JavaScript on the client side for webpage behavior. Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js. JavaScript is a high-level, often just-in-time–compiled language that conforms to the ECMAScript standard. It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM). The ECMAScript standard does not include any input/output (I/O), such as netwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrocardiography
Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including: * Cardiac rhythmicity, Cardiac rhythm disturbances, such as atrial fibrillation and ventricular tachycardia; * Inadequate coronary artery blood flow, such as myocardial ischemia and myocardial infarction; * and electrolyte disturbances, such as hypokalemia. Traditionally, "ECG" usually means a 12-lead ECG taken while lying down as discussed below. However, other devices can record the electrical activity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V-4 (rocket Launch)
V-4 was the first mostly-successful launch of the Aggregat 4 rocket, later known as (''V-2''). The launch occurred on the afternoon of 3 October 1942 and the rocket set a speed record of Mach 4, reached an apogee of , thereby becoming the first artificial object to reach both the mesosphere and the thermosphere, surpassing the apogee of set by the Paris gun in 1918. At the time, the V-4 launch was considered the first time a man-made object reached outer space (, "Birthday of spaceflight"). That evening, Walter Dornberger declared in a speech at Peenemunde, In 1960, the World Air Sports Federation (FAI) defined a boundary for space at (approximately the highest possible altitude where an aircraft can fly at less than orbital velocity in order not to stall), while the United States' Air Force, NASA and Federal Aviation Administration consider the space boundary, the lower mesopause. The V-4 launch satisfied the present-day American definition, while it did not cross th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visegrád Group
The Visegrád Group (also known as the Visegrád Four or the V4) is a cultural and political alliance of four Central European countries: the Czech Republic, Hungary, Poland, and Slovakia. The alliance aims to advance co-operation in military, economic, cultural and energy affairs. All four nations are also members of the European Union, the North Atlantic Treaty Organization, and the Three Seas Initiative. The alliance traces its origins to the summit meetings of leaders of Czechoslovakia, Hungary and Poland, held in the Hungarian castle town of Visegrád on 15 February 1991. Visegrád was chosen as the location for the summits as an intentional allusion to the medieval Congress of Visegrád between John I of Bohemia, Charles I of Hungary, and Casimir III of Poland in 1335. After the dissolution of Czechoslovakia in 1993, the Czech Republic and Slovakia became independent members of the alliance, increasing the number of members from three to four. All four members of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheinbote
''Rheinbote'' (''Rhine Messenger'') was a German short range ballistic rocket developed by Rheinmetall-Borsig at Berlin- Marienfelde during World War II. It was intended to replace, or at least supplement, large-bore artillery by providing fire support at long ranges in an easily transportable form. History One of the problems for the German military, and indeed any mobile military force, is the weight of the artillery and, more importantly, its ammunition supply. Battlefield rockets were intended to circumvent the problems, which led to the development of ''Rheinbote''. The ''Rheinbote'' was the successor of the earlier '' Rheintochter'' (Rhine Maiden). Developed in 1943 by the Rheinmetall-Borsig company, ''Rheinbote'' was a four-stage solid-fuelled rocket, and the only long-range battlefield ballistic missile to enter service in World War II. The first test flights were carried out that year. Several changes were made to the system, but the basic design remained the same. It m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint Kitts & Nevis
Saint Kitts and Nevis, officially the Federation of Saint Christopher (St Kitts) and Nevis, is an island country consisting of the two islands of Saint Kitts and Nevis, both located in the West Indies, in the Leeward Islands chain of the Lesser Antilles. With of territory, and roughly 48,000 inhabitants, it is the smallest sovereign state in the Western Hemisphere, in both area and population, as well as the world's smallest sovereign federation. The country is a Commonwealth realm, with Charles III as king and head of state. The capital city is Basseterre, located on the larger island of Saint Kitts. Basseterre is also the main port for passenger entry (via cruise ships) and cargo. The smaller island of Nevis lies approximately to the southeast of Saint Kitts, across a shallow channel called The Narrows. The British dependency of Anguilla was historically also a part of this union, which was known collectively as Saint Christopher-Nevis-Anguilla. However, Anguilla chose to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
