Letter (alphabet)A letter is a segmental symbol of a phonemic writing system. The inventory of all letters forms an alphabet. Letters broadly correspond to phonemes in the spoken form of the language, although there is rarely a consistent and exact correspondence between letters and phonemes. The word letter, borrowed from Old French letre, entered Middle English around 1200 AD, eventually displacing the Old English term bōcstæf (bookstaff). Letter is descended from the Latin littera, which may have descended from the Greek "διφθέρα" (, writing tablet), via Etruscan.
Korean phonologyThis article is a technical description of the phonetics and phonology of Korean. Unless otherwise noted, statements in this article refer to South Korean standard language based on the Seoul dialect. Morphophonemes are written inside double slashes (⫽ ⫽), phonemes inside slashes (/ /), and allophones inside brackets ([ ]). Korean has 19 consonant phonemes. For each plosive and affricate, there is a three-way contrast between unvoiced segments, which are distinguished as plain, tense, and aspirated.
Weighing scaleA scale or balance is a device used to measure weight or mass. These are also known as mass scales, weight scales, mass balances, and weight balances. The traditional scale consists of two plates or bowls suspended at equal distances from a fulcrum. One plate holds an object of unknown mass (or weight), while objects of known mass or weight, called weights, are added to the other plate until static equilibrium is achieved and the plates level off, which happens when the masses on the two plates are equal.
WiMAXWorldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMAX Forum was formed in June 2001 to promote conformity and interoperability, including the definition of system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL".
X-rayX-ray radiation, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3e16Hz to 3e19Hz) and energies in the range 124 keV to 145 eV, respectively. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays.
I486The Intel 486, officially named i486 and also known as 80486, is a microprocessor. It is a higher-performance follow-up to the Intel 386. The i486 was introduced in 1989. It represents the fourth generation of binary compatible CPUs following the 8086 of 1978, the Intel 80286 of 1982, and 1985's i386. It was the first tightly-pipelined x86 design as well as the first x86 chip to include more than one million transistors. It offered a large on-chip cache and an integrated floating-point unit.
Neutrino oscillationNeutrino oscillation is a quantum mechanical phenomenon in which a neutrino created with a specific lepton family number ("lepton flavor": electron, muon, or tau) can later be measured to have a different lepton family number. The probability of measuring a particular flavor for a neutrino varies between three known states, as it propagates through space. First predicted by Bruno Pontecorvo in 1957, neutrino oscillation has since been observed by a multitude of experiments in several different contexts.
ATLAS experimentATLAS is the largest general-purpose particle detector experiment at the Large Hadron Collider (LHC), a particle accelerator at CERN (the European Organization for Nuclear Research) in Switzerland. The experiment is designed to take advantage of the unprecedented energy available at the LHC and observe phenomena that involve highly massive particles which were not observable using earlier lower-energy accelerators. ATLAS was one of the two LHC experiments involved in the discovery of the Higgs boson in July 2012.
Athlon 64 X2The Athlon 64 X2 is the first native dual-core desktop central processing unit (CPU) designed by Advanced Micro Devices (AMD). It was designed from scratch as native dual-core by using an already multi-CPU enabled Athlon 64, joining it with another functional core on one die, and connecting both via a shared dual-channel memory controller/north bridge and additional control logic. The initial versions are based on the E stepping model of the Athlon 64 and, depending on the model, have either 512 or 1024 KB of L2 cache per core.
X-ray astronomyX-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy uses a type of space telescope that can see x-ray radiation which standard optical telescopes, such as the Mauna Kea Observatories, cannot.
X86 instruction listingsThe x86 instruction set refers to the set of instructions that x86-compatible microprocessors support. The instructions are usually part of an executable program, often stored as a and executed on the processor. The x86 instruction set has been extended several times, introducing wider registers and datatypes as well as new functionality. x86 assembly language Below is the full 8086/8088 instruction set of Intel (81 instructions total). Most if not all of these instructions are available in 32-bit mode; they just operate on 32-bit registers (eax, ebx, etc.
X-ray tubeAn X-ray tube is a vacuum tube that converts electrical input power into X-rays. The availability of this controllable source of X-rays created the field of radiography, the imaging of partly opaque objects with penetrating radiation. In contrast to other sources of ionizing radiation, X-rays are only produced as long as the X-ray tube is energized. X-ray tubes are also used in CT scanners, airport luggage scanners, X-ray crystallography, material and structure analysis, and for industrial inspection.
