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#2494. What does the medical term Bypass surgery mean?

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#6268.

2362) Gerhard Herzberg

Gist:

Work

Our world consists of atoms that are assembled in molecules. During many chemical reactions, molecules are broken down into smaller parts, free radicals, that are quickly combined with other parts and form new molecules. Molecules absorb light of fixed wavelengths, and these light spectrums can be used with quantum mechanical calculations to figure out how different molecules are constructed. Gerhard Herzberg developed these methods, and during the 1950s and 1960s he mapped out the chemical structure of a great many free radicals.

Summary

Gerhard Herzberg (born Dec. 25, 1904, Hamburg, Ger.—died March 3, 1999, Ottawa, Ont., Can.) was a Canadian physicist and winner of the 1971 Nobel Prize for Chemistry for his work in determining the electronic structure and geometry of molecules, especially free radicals—groups of atoms that contain odd numbers of electrons. His work provided the foundation for molecular spectroscopy.

Herzberg became Privatdozent (unsalaried lecturer) at the Darmstadt Institute of Technology in 1930 but fled Nazi Germany in 1935 and obtained a position with the University of Saskatchewan. From 1945 to 1948 he worked at the University of Chicago’s Yerkes Observatory in Williams Bay, Wisconsin, after which he returned to Canada, where he joined the National Research Council, Ottawa.

Herzberg’s spectroscopic studies not only provided experimental results of prime importance to physical chemistry and quantum mechanics but also helped stimulate a resurgence of investigations into the chemical reactions of gases. He devoted much of his research to diatomic molecules, in particular the most common ones—hydrogen, oxygen, nitrogen, and carbon monoxide. He discovered the spectra of certain free radicals that are intermediate stages in numerous chemical reactions, and he was the first to identify the spectra of certain radicals in interstellar gas. Herzberg also contributed much spectrographic information on the atmospheres of the outer planets and the stars. His most important works are Atomspektren und Atomstruktur (1936; Atomic Spectra and Atomic Structure) and a long-standing reference work, the four-volume Molecular Spectra and Molecular Structure (1939–79).

Details

Gerhard Heinrich Friedrich Otto Julius Herzberg (December 25, 1904 – March 3, 1999) was a German-Canadian pioneering physicist and physical chemist, who won the Nobel Prize for Chemistry in 1971, "for his contributions to the knowledge of electronic structure and geometry of molecules, particularly free radicals". Herzberg's main work concerned atomic and molecular spectroscopy. He is well known for using these techniques that determine the structures of diatomic and polyatomic molecules, including free radicals which are difficult to investigate in any other way, and for the chemical analysis of astronomical objects. Herzberg served as Chancellor of Carleton University in Ottawa, Canada from 1973 to 1980.

Early life and family

Herzberg was born in Hamburg, Germany on December 25, 1904 to Albin H. Herzberg and Ella Biber. He had an older brother, Walter, who was born in January 1904. Herzberg started Vorschule (pre-school) late, after contracting measles. Gerhard and his family were atheists and kept this fact hidden. His father died in 1914, at 43 years of age, after having suffered from dropsy and complications due to an earlier heart condition. Herzberg graduated Vorschule shortly after his father's death. He married Luise Herzberg (née Oettinger), a spectroscopist and fellow researcher in 1929. (Luise Herzberg, died in 1971.)

Honours and awards

Herzberg's most significant award was the 1971 Nobel Prize in Chemistry, which he was awarded "for his contributions to the knowledge of electronic structure and geometry of molecules, particularly free radicals". During the presentation speech, it was noted that at the time of the award, Herzberg was "generally considered to be the world's foremost molecular spectroscopist."

Herzberg was honoured with memberships or fellowships by a very large number of scientific societies, received many awards and honorary degrees in different countries. The NSERC Gerhard Herzberg Canada Gold Medal for Science and Engineering, Canada's highest research award, was named in his honour in 2000. The Canadian Association of Physicists also has an annual award named in his honour. The Herzberg Institute of Astrophysics is named for him. He was made a member of the International Academy of Quantum Molecular Science. Asteroid 3316 Herzberg is named after him. In 1964 he was awarded the Frederic Ives Medal by the OSA. He was later named an Honorary Member of the Society. At Carleton University, there is a building named after him that belongs to the Physics and Mathematics/Statistics Departments, Herzberg Laboratories. Herzberg was elected a Fellow of the Royal Society (FRS) in 1951.

The main building of John Abbott College in Montreal is named after him. Carleton University named the Herzberg Laboratories building after him. A public park in the College Park neighbourhood of Saskatoon also bears his name.

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#2493. What does the medical term Butterfly rash mean?

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#6267.

2361) Dennis Gabor

Gist:

Work

During the 19th century photographic methods were developed that resulted in two-dimensional images. In 1951 Dennis Gabor discovered a way of producing images with the illusion of depth. The method was based on interference—interaction between light waves—and coherence—light waves aligned in phase with one another. Light falling on an object is captured on photographic film along with a reference beam that did not fall on the object. When only the reference beam falls on the developed film, the light is bent so that a reproduction with depth is produced.

Summary

Dennis Gabor (born June 5, 1900, Budapest, Hung.—died Feb. 8, 1979, London, Eng.) was a Hungarian-born electrical engineer who won the Nobel Prize for Physics in 1971 for his invention of holography, a system of lensless, three-dimensional photography that has many applications.

A research engineer for the firm of Siemens and Halske in Berlin from 1927, Gabor fled Nazi Germany in 1933 and worked with the Thomson-Houston Company in England, later becoming a British subject. In 1947 he conceived the idea of holography and, by employing conventional filtered-light sources, developed the basic technique. Because conventional light sources generally provided either too little light or light that was too diffuse, holography did not become commercially feasible until the demonstration, in 1960, of the laser, which amplifies the intensity of light waves.

In 1949 Gabor joined the faculty of the Imperial College of Science and Technology, London, where in 1958 he became professor of applied electron physics. His other work included research on high-speed oscilloscopes, communication theory, physical optics, and television. Gabor was awarded more than 100 patents.

Details

Dennis Gabor (5 June 1900 – 9 February 1979) was a Hungarian-British physicist who received the Nobel Prize in Physics in 1971 for his invention of holography. He obtained British citizenship in 1946 and spent most of his life in England.

Life and career

Gabor was born as Günszberg Dénes, into a Jewish family in Budapest, Austria-Hungary. In 1900, his family converted to Lutheranism. Dennis was the first-born son of Günszberg Bernát and Jakobovits Adél. Despite having a religious background, religion played a minor role in his later life and he considered himself agnostic. In 1902, the family received permission to change their surname from Günszberg to Gábor. He served with the Hungarian artillery in northern Italy during World War I.

He began his studies in engineering at the Budapest University of Technology and Economics in 1918, later in Germany, at the Technische Hochschule Charlottenburg in Berlin, now known as Technische Universität Berlin. At the start of his career, he analysed the properties of high voltage electric transmission lines by using cathode-beam oscillographs, which led to his interest in electron optics. Studying the fundamental processes of the oscillograph, Gabor was led to other electron-beam devices such as electron microscopes and TV tubes. He eventually wrote his PhD thesis on Recording of Transients in Electric Circuits with the Cathode Ray Oscillograph in 1927, and worked on plasma lamps.

In 1933 Gabor fled from Nazi Germany, where he was considered Jewish, and was invited to Britain to work at the development department of the British Thomson-Houston company in Rugby, Warwickshire. During his time in Rugby, he met Marjorie Louise Butler, and they married in 1936. He became a British citizen in 1946, and it was while working at British Thomson-Houston in 1947 that he invented holography, based on an electron microscope, and thus electrons instead of visible light. He experimented with a heavily filtered mercury arc light source. The earliest visual hologram was only realised in 1964 following the 1960 invention of the laser, the first coherent light source. After this, holography became commercially available.

Gabor's research focused on electron inputs and outputs, which led him to the invention of holography. The basic idea was that for perfect optical imaging, the total of all the information has to be used; not only the amplitude, as in usual optical imaging, but also the phase. In this manner, a complete holo-spatial picture can be obtained. Gabor published his theories of holography in a series of papers between 1946 and 1951.

Gabor also researched how human beings communicate and hear; the result of his investigations was the theory of granular synthesis, although Greek composer Iannis Xenakis claimed that he was actually the first inventor of this synthesis technique. Gabor's work in this and related areas was foundational in the development of time–frequency analysis.

In 1948 Gabor moved from Rugby to Imperial College London, and in 1958 became professor of Applied Physics until his retirement in 1967. His inaugural lecture on 3 March 1959, 'Electronic Inventions and their Impact on Civilisation' provided inspiration for Norbert Wiener's treatment of self-reproducing machines in the penultimate chapter in the 1961 edition of his book Cybernetics.

As part of his many developments related to CRTs, in 1958 Gabor patented a new flat screen television concept. This used an electron gun aimed perpendicular to the screen, rather than straight at it. The beam was then directed forward to the screen using a series of fine metal wires on either side of the beam path. The concept was significantly similar to the Aiken tube, introduced in the US the same year. This led to a many-years patent battle which resulted in Aiken keeping the US rights and Gabor the UK. Gabor's version was later picked up by Clive Sinclair in the 1970s, and became a decades-long quest to introduce the concept commercially. Its difficult manufacturing, due to the many wires within the vacuum tube, meant this was never successful. While looking for a company willing to try to manufacture it, Sinclair began negotiations with Timex, who instead took over production of the ZX81.

In 1963 Gabor published Inventing the Future which discussed the three major threats Gabor saw to modern society: war, overpopulation and the Age of Leisure. The book contained the now well-known expression that "the future cannot be predicted, but futures can be invented." Reviewer Nigel Calder described his concept as, "His basic approach is that we cannot predict the future, but we can invent it..." Others such as Alan Kay, Peter Drucker, and Forrest Shaklee have used various forms of similar quotes. His next book, Innovations: scientific, technological, and social which was published in 1970, expanded on some of the topics he had already earlier touched upon, and also pointed to his interest in technological innovation as mechanism of both liberation and destruction.

In 1971 he was the single recipient of the Nobel Prize in Physics with the motivation "for his invention and development of the holographic method" and presented the history of the development of holography from 1948 in his Nobel lecture.

While spending much of his retirement in Italy at Lavinio Rome, he remained connected with Imperial College as a senior research fellow and also became staff scientist of CBS Laboratories, in Stamford, Connecticut; there, he collaborated with his lifelong friend, CBS Labs' president Dr. Peter C. Goldmark in many new schemes of communication and display. One of Imperial College's new halls of residence in Prince's Gardens, Knightsbridge is named Gabor Hall in honour of Gabor's contribution to Imperial College. He developed an interest in social analysis and published The Mature Society: a view of the future in 1972. He also joined the Club of Rome and supervised a working group studying energy sources and technical change. The findings of this group were published in the report Beyond the Age of Waste in 1978, a report which was an early warning of several issues that only later received widespread attention.

Following the rapid development of lasers and a wide variety of holographic applications (e.g., art, information storage, and the recognition of patterns), Gabor achieved acknowledged success and worldwide attention during his lifetime. He received numerous awards besides the Nobel Prize.

Gabor died in a nursing home in South Kensington, London, on 9 February 1979. In 2006 a blue plaque was put up on No. 79 Queen's Gate in Kensington, where he lived from 1949 until the early 1960s.

Personal life

On 8 August 1936, he married Marjorie Louise Butler. They did not have any children.

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#10603. What does the term in Geography Cardinal directions mean?

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#2492. What does the medical term Bogota bag mean?