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JJY
JJY is the call sign of a low frequency time signal radio station located in Japan. The station broadcasts from two sites, one on Mount Otakadoya, near Fukushima, and the other on Mount Hagane, located on Kyushu Island. JJY is operated by the National Institute of Information and Communications Technology (NICT), an independent administrative institution affiliated with the Ministry of Internal Affairs and Communications of the Japanese government. Transmission sites The Mount Otakadoya site () is located at an elevation of 790 meters (2,590 ft) in Fukushima Prefecture. It broadcasts a 50 kW signal (13 kW ERP) on 40 kHz from an umbrella top-loading antenna situated 250 meters (820 ft) above the ground. In March 2011, it was powered down and evacuated due to its proximity to the Fukushima Daiichi nuclear disaster. It resumed broadcasting on April 21, unattended by staff. It went off air again temporarily on April 25 due to lightning, but has ever since been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otakadoyayama Transmitter
Otakadoyayama Transmitter (おおたかどや山標準電波送信所, ') is an LF-time signal transmitter at Tamura-City, Fukushima-ken, Japan used for transmitting the time signal JJY on 40 kHz. The Otakadoyama site is one of two JJY transmitters, another is the Haganeyama site. Summy * NAME： NICT Otakadoyayama LF station * Location：Summit of Mt. Otakadoya, Tamura-City, Fukushima-ken * Elevation：about 790m * Latitude：37°22'21.0"N * Longitude：140°50'56.0"E * License： NICT * Station purpose：Transmitting the official Japanese government frequency standards and time signal * Frequency form：250H A1B * Frequency：40kHz * Antenna power：50 kW（Antenna efficiency: about 45%） * Antenna form：Umbrella type 250m high * Operation time：continuously * Operation start：1999/06/01 * Range：About 1,000 km * Transmission method : See also * Haganeyama Transmitter Haganeyama Transmitter (はがね山標準電波送信所, ') is an LF-time signal transmitter a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haganeyama Transmitter
Haganeyama Transmitter (はがね山標準電波送信所, ') is an LF-time signal transmitter at Fuji-cho, Saga-city, Saga-ken, Japan used for transmitting the time signal JJY on 60 kHz. The Haganeyama site is one of two JJY transmitters, another is the Otakadoyama site. Summy * NAME： NICT Haganeyama LF station * Location：Summit of Mt. Hagane, Fuji-cho, Saga-city, Saga-ken * Elevation：about 900m * Latitude：33°27'56.0"N * Longitude：130°10'32.0"E * License： NICT * Station purpose：Transmitting the official Japanese government frequency standards and time signal * Frequency form：250H A1B * Frequency：60kHz * Antenna power：50 kW（Antenna efficiency: about 45%） * Antenna form：Umbrella type 200m high * Operation time：continuously * Operation start：2001/10/01 * Range：About 1,000 km * Transmission method : See also * Otakadoyayama Transmitter Otakadoyayama Transmitter (おおたかどや山標準電波送信所, ') is an LF-time signal transmitte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WWVB
WWVB is a time signal radio station near Fort Collins, Colorado and is operated by the National Institute of Standards and Technology (NIST). Most radio-controlled clocks in North America use WWVB's transmissions to set the correct time. The 70 kW ERP signal transmitted from WWVB is a continuous 60 kHz carrier wave, the frequency of which is derived from a set of atomic clocks located at the transmitter site, yielding a frequency uncertainty of less than 1 part in 10. A one-bit-per-second time code, which is based on the IRIG "H" time code format and derived from the same set of atomic clocks, is then modulated onto the carrier wave using pulse-width modulation and amplitude-shift keying. A single complete frame of time code begins at the start of each minute, lasts one minute, and conveys the year, day of year, hour, minute, and other information . WWVB is co-located with WWV, a time signal station that broadcasts in both voice and time code on multiple shortwave r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japan Standard Time
, or , is the standard time zone in Japan, 9 hours ahead of UTC ( UTC+09:00). Japan does not observe daylight saving time, though its introduction has been debated on several occasions. During World War II, the time zone was often referred to as Tokyo Standard Time. Japan Standard Time is equivalent to Korean Standard Time, Pyongyang Time (North Korea), Eastern Indonesia Standard Time, East-Timorese Standard Time and Yakutsk Time (Russia). History Before the Meiji era (1868–1912), each local region had its own time zone in which noon was when the sun was exactly at its culmination. As modern transportation methods, such as trains, were adopted, this practice became a source of confusion. For example, there is a difference of about 5 degrees longitude between Tokyo and Osaka and because of this, a train that departed from Tokyo would arrive at Osaka 20 minutes behind the time in Tokyo. In 1886, Ordinance 51 was issued in response to this problem, which stated: Accordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Call Sign
In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigned by a government agency, informally adopted by individuals or organizations, or even cryptographically encoded to disguise a station's identity. The use of call signs as unique identifiers dates to the landline railroad telegraph system. Because there was only one telegraph line linking all railroad stations, there needed to be a way to address each one when sending a telegram. In order to save time, two-letter identifiers were adopted for this purpose. This pattern continued in radiotelegraph operation; radio companies initially assigned two-letter identifiers to coastal stations and stations onboard ships at sea. These were not globally unique, so a one-letter company identifier (for instance, 'M' and two letters as a Marconi station ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PC Magazine
''PC Magazine'' (shortened as ''PCMag'') is an American computer magazine published by Ziff Davis. A print edition was published from 1982 to January 2009. Publication of online editions started in late 1994 and have continued to the present day. Overview ''PC Magazine'' provides reviews and previews of the latest hardware and software for the information technology professional. Articles are written by leading experts including John C. Dvorak, whose regular column and "Inside Track" feature were among the magazine's most popular attractions. Other regular departments include columns by long-time editor-in-chief Michael J. Miller ("Forward Thinking"), Bill Machrone, and Jim Louderback, as well as: * "First Looks" (a collection of reviews of newly released products) * "Pipeline" (a collection of short articles and snippets on computer-industry developments) * "Solutions" (which includes various how-to articles) * "User-to-User" (a section in which the magazine's experts answ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Shielding
In electrical engineering, electromagnetic shielding is the practice of reducing or blocking the electromagnetic field (EMF) in a space with barriers made of conductive or magnetic materials. It is typically applied to enclosures, for isolating electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs (). Electromagnetic shielding that blocks radio frequency (RF) electromagnetic radiation is also known as RF shielding. EMF shielding serves to minimize electromagnetic interference. The shielding can reduce the coupling of radio waves, electromagnetic fields, and electrostatic fields. A conductive enclosure used to block electrostatic fields is also known as a '' Faraday cage''. The amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of holes in a shield to an incident electromagn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HVAC
Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and Sick building syndrome, healthy building conditions are regulated with respect to temperature and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 million residents ; the city proper has a population of 13.99 million people. Located at the head of Tokyo Bay, the prefecture forms part of the Kantō region on the central coast of Honshu, Japan's largest island. Tokyo serves as Japan's economic center and is the seat of both the Japanese government and the Emperor of Japan. Originally a fishing village named Edo, the city became politically prominent in 1603, when it became the seat of the Tokugawa shogunate. By the mid-18th century, Edo was one of the most populous cities in the world with a population of over one million people. Following the Meiji Restoration of 1868, the imperial capital in Kyoto was moved to Edo, which was renamed "Tokyo" (). Tokyo was devastate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Clock
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, \Delta \nu_\mathsf, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This definition is the basis for the system of International Atomic Time (TAI), which is maintained by an ensemble of atomic clocks around the world. The system of Coordinated Universal Time, Coordinated Universal Time (UTC) that is the basis of civil time implements ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium
Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at . It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. The element has 40 known isotopes, making it, along with barium and mercury, one of the elements with the most isotopes. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors. The German chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opacity (optics), opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), Carbon dioxide in Earth's atmosphere, carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration (physiology), respiration; lightning and bacteria perform nitrogen fixation to produce ammonia that is used to make nucleotides and amino acids; plants, algae, and cyanobacteria use carbon dioxide for photosynthesis. The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, the solar win ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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