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Kinjiro Okabe
was a Japanese electrical engineering researcher and professor who made major contributions to magnetron and radar development. He did work after the Second World War on medical instruments using ultrasounds. Career Split-anode magnetron One of Japan's best-known radio researchers in the 1920s-1930s era was Professor Hidetsugu Yagi, who was initially at Tohoku University. He had become very interested in the magnetron, built and named by Albert W. Hull at General Electric in 1921. While Hull's magnetron was a HF device, Yagi was convinced that it could also be a generator of VHF or even UHF signals. Kinjiro Okabe was one of Yagi's first doctoral students and was encouraged by his mentor in this pursuit. In 1926, Okabe developed a magnetron device that significantly decreased the operating wavelength of oscillations. He filed for a U.S. patent in 1926, which was granted in 1929 (No. 1,735,294). His work continued, and based on developing the split-anode device, he was awar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetron
The cavity magnetron is a high-power vacuum tube used in early radar systems and currently in microwave ovens and linear particle accelerators. It generates microwaves using the interaction of a stream of electrons with a magnetic field while moving past a series of cavity resonators, which are small, open cavities in a metal block. Electrons pass by the cavities and cause microwaves to oscillate within, similar to the functioning of a whistle producing a tone when excited by an air stream blown past its opening. The resonant frequency of the arrangement is determined by the cavities' physical dimensions. Unlike other vacuum tubes, such as a klystron or a traveling-wave tube (TWT), the magnetron cannot function as an amplifier for increasing the intensity of an applied microwave signal; the magnetron serves solely as an oscillator, generating a microwave signal from direct current electricity supplied to the vacuum tube. The use of magnetic fields as a means to control the flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yoji Ito
was an engineer and scientist who had a major role in the Japanese development of magnetrons and the Radio Range Finder (RRF – the code name for a radar). Early years Yoji Ito was born and raised in Onjuku, then a fishing village in the Chiba Prefecture of Japan. His father was the primary schoolmaster and encouraged his children to achieve science and mathematics excellence. After graduating in electrical engineering from the Tokyo Imperial University, Ito was commissioned in the Imperial Navy and spent several years in assignments at sea. At the NTRI Still in the Navy, Yoji Ito was sent to Germany for graduate study where he was a student of Heinrich Barkhausen at the Dresden Technische Hochschule. Upon completing his Doctor of Engineering degree there in 1929, he was promoted to the rank of Commander and assigned as a researcher at the Naval Technology Research Institute (NTRI) in the Meguro area of Tokyo. The NTRI had been formed in 1922, and was just becoming fully ope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Scientists
Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspora, Japanese emigrants and their descendants around the world * Japanese citizens, nationals of Japan under Japanese nationality law ** Foreign-born Japanese, naturalized citizens of Japan * Japanese writing system, consisting of kanji and kana * Japanese cuisine, the food and food culture of Japan See also * List of Japanese people * * Japonica (other) * Japonicum * Japonicus * Japanese studies Japanese studies (Japanese: ) or Japan studies (sometimes Japanology in Europe), is a sub-field of area studies or East Asian studies involved in social sciences and humanities research on Japan. It incorporates fields such as the study of Japanese ... {{disambiguation Language and nationality disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Electrical Engineers
Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspora, Japanese emigrants and their descendants around the world * Japanese citizens, nationals of Japan under Japanese nationality law ** Foreign-born Japanese, naturalized citizens of Japan * Japanese writing system, consisting of kanji and kana * Japanese cuisine, the food and food culture of Japan See also * List of Japanese people * * Japonica (other) * Japonicum * Japonicus * Japanese studies Japanese studies ( Japanese: ) or Japan studies (sometimes Japanology in Europe), is a sub-field of area studies or East Asian studies involved in social sciences and humanities research on Japan. It incorporates fields such as the study of Japan ... {{disambiguation Language and nationality disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1984 Deaths
Events January * January 1 – The Bornean Sultanate of Brunei gains full independence from the United Kingdom, having become a British protectorate in 1888. * January 7 – Brunei becomes the sixth member of the Association of Southeast Asian Nations (ASEAN). * January 10 ** The United States and the Vatican (Holy See) restore full diplomatic relations. ** The Victoria Agreement is signed, institutionalising the Indian Ocean Commission. *January 24 – Steve Jobs launches the Macintosh personal computer in the United States. February * February 3 ** Dr. John Buster and the research team at Harbor–UCLA Medical Center announce history's first embryo transfer from one woman to another, resulting in a live birth. ** STS-41-B: Space Shuttle ''Challenger'' is launched on the 10th Space Shuttle mission. * February 7 – Astronauts Bruce McCandless II and Robert L. Stewart make the first untethered space walk. * February 8– 19 – The 1984 Winter Olympics are held i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1896 Births
Events January–March * January 2 – The Jameson Raid comes to an end, as Jameson surrenders to the Boers. * January 4 – Utah is admitted as the 45th U.S. state. * January 5 – An Austrian newspaper reports that Wilhelm Röntgen has discovered a type of radiation (later known as X-rays). * January 6 – Cecil Rhodes is forced to resign as Prime Minister of the Cape of Good Hope, for his involvement in the Jameson Raid. * January 7 – American culinary expert Fannie Farmer publishes her first cookbook. * January 12 – H. L. Smith takes the first X-ray photograph. * January 17 – Fourth Anglo-Ashanti War: British redcoats enter the Ashanti capital, Kumasi, and Asantehene Agyeman Prempeh I is deposed. * January 18 – The X-ray machine is exhibited for the first time. * January 28 – Walter Arnold, of East Peckham, Kent, England, is fined 1 shilling for speeding at (exceeding the contemporary speed limit of , the first spee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasound
Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 Hertz, kilohertz (20,000 hertz) in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating Predation, prey and obstacles. History Acoustics, the science of sound, starts as far back as Pyth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigeo Satomura
was a Japanese physicist credited with introducing the ultrasonic Doppler techniques to practical medical diagnostics in the 1950s. These techniques made possible non-invasive monitoring of blood flow in the human body. Life Satomura was born in 1919 in Osaka and spent most of his career at various institutions of Osaka University. In 1944 he defended his PhD at the School of Physics and then worked at the Institute of Scientific and Industrial Research. In 1952 he became assistant professor and received a Doctor of Medicine degree in 1960. He died from a sudden subarachnoid hemorrhage at the Osaka University Hospital in the same year and was promoted to the rank of professor posthumously.Shigeo Satomura History of Ultrasound in Obstetrics and Gynecology. ob-ultrasound.net Research Satomura initially worked in areas of ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order Of Culture
The is a Japanese order, established on February 11, 1937. The order has one class only, and may be awarded to men and women for contributions to Japan's art, literature, science, technology, or anything related to culture in general; recipients of the order also receive an annuity for life. The order is conferred by the Emperor of Japan in person on Culture Day (November 3) each year. It is considered equivalent to the highest rank (Grand Cordon) of the Order of the Rising Sun, the Order of the Sacred Treasure, and the Order of the Precious Crown. The only orders that Japanese emperors bestow on recipients by their own hands are the Collar of the Supreme Order of the Chrysanthemum, the Grand Cordon of each order, and the Order of Culture. The badge of the order, which is in gold with white enamel, is in the form of a Tachibana orange blossom; the central disc bears three crescent-shaped jades ('' magatama''). The badge is suspended on a gold and enamel wreath of mandarin or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barkhausen–Kurz Tube
The Barkhausen–Kurz tube, also called the retarding-field tube, reflex triode, B–K oscillator, and Barkhausen oscillator was a high frequency vacuum tube electronic oscillator invented in 1920 by German physicists Heinrich Georg Barkhausen and Karl Kurz. It was the first oscillator that could produce radio power in the ultra-high frequency (UHF) portion of the radio spectrum, above 300 MHz. It was also the first oscillator to exploit electron transit time effects. It was used as a source of high frequency radio waves in research laboratories, and in a few UHF radio transmitters through World War 2. Its output power was low which limited its applications. However it inspired research that led to other more successful transit time tubes such as the klystron, which made the low power Barkhausen-Kurz tube obsolete. History The triode vacuum tube developed by Lee de Forest in 1906 was the first device that could amplify, and was used in most radio transmitters and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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