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Fernand Holweck
Fernand Holweck (21 July 1890 – 24 December 1941) was a French physicist who made important contributions in the fields of vacuum technology, electromagnetic radiation and gravitation. He is also remembered for his personal sacrifice in the cause of the French Resistance and his aid to Allied airmen in World War II. Biography Holweck was born on 21 July 1890 to a family from the Alsace Region who had opted to remain French at the end of the Franco-Prussian war in 1870. He studied at the École supérieure de physique et de chimie industrielles de la ville de Paris (ESPCI), where he graduated top of his class in engineering physics and became personal assistant to Marie Curie. During his military service he worked under the wireless telegraphy pioneer Gustave-Auguste Ferrié at the Eiffel Tower radio station, and by 1914 he had produced his first patent, relating to thermionic tubes. During World War I, 1914–1918, he served first at the front, working on methods to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. Since the 17th century, Paris has been one of the world's major centres of finance, diplomacy, commerce, fashion, gastronomy, and science. For its leading role in the arts and sciences, as well as its very early system of street lighting, in the 19th century it became known as "the City of Light". Like London, prior to the Second World War, it was also sometimes called the capital of the world. The City of Paris is the centre of the Île-de-France region, or Paris Region, with an estimated population of 12,262,544 in 2019, or about 19% of the population of France, making the region France's primate city. The Paris Region had a GDP of €739 billion ($743 billion) in 2019, which is the highest in Europe. According to the Economist Intelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Signal
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (shorter than a grain of rice); at 30 Hz the corresponding wavelength is (longer than the radius of the Earth). Like all electromagnetic waves, radio waves in a vacuum travel at the speed of light, and in the Earth's atmosphere at a close, but slightly lower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects, and are part of the blackbody radiation emitted by all warm objects. Radio waves are generated artificially by an electronic device called a transmitter, which is connected to an antenna which radiates the waves. They are received by another antenna connected to a radio receiver, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycée
In France, secondary education is in two stages: * ''Collèges'' () cater for the first four years of secondary education from the ages of 11 to 15. * ''Lycées'' () provide a three-year course of further secondary education for children between the ages of 15 and 18. Pupils are prepared for the ''baccalauréat'' (; baccalaureate, colloquially known as ''bac'', previously ''bachot''), which can lead to higher education studies or directly to professional life. There are three main types of ''baccalauréat'': the ''baccalauréat général'', ''baccalauréat technologique'' and ''baccalauréat professionnel''. School year The school year starts in early September and ends in early July. Metropolitan French school holidays are scheduled by the Ministry of Education (France), Ministry of Education by dividing the country into three zones (A, B, and C) to prevent overcrowding by family holidaymakers of tourist destinations, such as the Mediterranean coast and ski resorts. Lyon, for exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fernand Holweck Medal And Prize
The Fernand Holweck Medal and Prize is a major European prize for Physics awarded jointly every year by the British Institute of Physics (IOP) and the Société Française de Physique (SFP). It is one of the four Grand Prix of the SFP and one of the four International Bilateral Awards of the IOP, consisting of a gold medal and a 3000€ cash prize. History The prize was established in 1945 as a memorial to Fernand Holweck and other French physicists who were persecuted or killed by the Nazis during the German occupation of France during World War II, from 1940 to 1945. It was originally a £150 prize. It is awarded for distinguished work in experimental physics (which reflects Holweck's scientific interest) or in theoretical physics which is closely related to experimentation. The Holweck Prize is awarded every year, alternately to a French physicist and a British or Irish physicist. In 1974 two awards were made to mark the centenaries of the two societies. Holweck Laureates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestapo
The (), abbreviated Gestapo (; ), was the official secret police of Nazi Germany and in German-occupied Europe. The force was created by Hermann Göring in 1933 by combining the various political police agencies of Prussia into one organisation. On 20 April 1934, oversight of the Gestapo passed to the head of the ''Schutzstaffel'' (SS), Heinrich Himmler, who was also appointed Chief of German Police by Hitler in 1936. Instead of being exclusively a Prussian state agency, the Gestapo became a national one as a sub-office of the (SiPo; Security Police). From 27 September 1939, it was administered by the Reich Security Main Office (RSHA). It became known as (Dept) 4 of the RSHA and was considered a sister organisation to the (SD; Security Service). During World War II, the Gestapo played a key role in the Holocaust. After the war ended, the Gestapo was declared a criminal organisation by the International Military Tribunal (IMT) at the Nuremberg trials. History After Adol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antoine De Saint-Exupéry
Antoine Marie Jean-Baptiste Roger, comte de Saint-Exupéry, simply known as Antoine de Saint-Exupéry (, , ; 29 June 1900 – 31 July 1944), was a French writer, poet, aristocrat, journalist and pioneering aviator. He became a laureate of several of France's highest literary awards and also won the United States National Book Award. He is best remembered for his novella ''The Little Prince'' (''Le Petit Prince'') and for his lyrical aviation writings, including ''Wind, Sand and Stars'' and '' Night Flight''. Saint-Exupéry was a successful commercial pilot before World War II, working airmail routes in Europe, Africa, and South America. He joined the French Air Force at the start of the war, flying reconnaissance missions until France's armistice with Germany in 1940. After being demobilised by the French Air Force, he travelled to the United States to help persuade its government to enter the war against Nazi Germany. Saint-Exupéry spent 28 months in America, during wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Reynaud
Paul Reynaud (; 15 October 1878 – 21 September 1966) was a French politician and lawyer prominent in the interwar period, noted for his stances on economic liberalism and militant opposition to Germany. Reynaud opposed the Munich Agreement of September 1938, when France and the United Kingdom gave way before Hitler's proposals for the dismemberment of Czechoslovakia. After the outbreak of World War II Reynaud became the penultimate Prime Minister of the Third Republic in March 1940. He was also vice-president of the Democratic Republican Alliance center-right party. Reynaud was Prime Minister during the German defeat of France in May and June 1940; he persistently refused to support an armistice with Germany, as premier in June 1940, he unsuccessfully attempted to save France from German occupation in World War II, and resigned on 16 June. After unsuccessfully attempting to flee France, he was arrested by Philippe Petain's administration. Surrendering to German custody in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salvador Luria
Salvador Edward Luria (August 13, 1912 – February 6, 1991) was an Italian microbiologist, later a naturalized U.S. citizen. He won the Nobel Prize in Physiology or Medicine in 1969, with Max Delbrück and Alfred Hershey, for their discoveries on the replication mechanism and the genetic structure of viruses. Salvador Luria also showed that bacterial resistance to viruses (phages) is genetically inherited. Biography Early life Luria was born Salvatore Edoardo Luria in Turin, Italy to an influential Italian Sephardi Jewish family. His parents were Davide and Ester (Sacerdote) Luria. He attended the medical school at the University of Turin studying with Giuseppe Levi. There, he met two other future Nobel laureates: Rita Levi-Montalcini and Renato Dulbecco. He graduated from the University of Turin in 1935 and never got a master's degree or a PhD as they were not contemplated by the Italian high educational system (which, on the other hand, was very selective). From 1936 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, entertainment, news, and sports. Television became available in crude experimental forms in the late 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion.Diggs-Brown, Barbara (2011''Strategic Public Relations: Audience Focused Practice''p. 48 In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries. The availability of various types of archival st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not consid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holweck Pump
A molecular drag pump is a type of vacuum pump that utilizes the drag of air molecules against a rotating surface. The most common sub-type is the ''Holweck pump'', which contains a rotating cylinder with spiral grooves which direct the gas from the high vacuum side of the pump to the low vacuum side of the pump. The older ''Gaede pump'' design is similar, but is much less common due to disadvantages in pumping speed. In general, molecular drag pumps are more efficient for heavy gasses, so the lighter gasses (hydrogen, deuterium, helium) will make up the majority of the residual gasses left after running a molecular drag pump. The turbomolecular pump invented in the 1950s, is a more advanced version based on similar operation, and a Holweck pump is often used as the backing pump for it. The Holweck pump can produce a vacuum as low as . History Gaede The earliest molecular drag pump was created by Wolfgang Gaede, who had the idea of the pump in 1905, and spent several years corresp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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