In 1917, Albert Einstein established the theoretical foundations for the laser and the maser in the paper Zur Quantentheorie der Strahlung ( On the Quantum Theory of Radiation ); via a re-derivation of Max Planck ’ s law of radiation, conceptually based upon probability coefficients ( Einstein coefficients ) for the absorption, spontaneous emission, and stimulated emission of electromagnetic radiation ; in 1928, Rudolf W. Ladenburg confirmed the existences of the phenomena of stimulated emission and negative absorption ; in 1939, Valentin A. Fabrikant predicted the use of stimulated emission to amplify “ short ” waves ; in 1947, Willis E. Lamb and R. C. Retherford found apparent stimulated emission in hydrogen spectra and effected the first demonstration of stimulated emission ; in 1950, Alfred Kastler ( Nobel Prize for Physics 1966 ) proposed the method of optical pumping, experimentally confirmed, two years later, by Brossel, Kastler, and Winter.

In 1939, the unit was renamed the Special Technical Bureau at the NKVD USSR ( Особое техническое бюро НКВД СССР ) and placed under the leadership of General Valentin Kravchenko, under Beria's immediate supervision.

He himself died during the early days of World War II in an accident caused by the collision of two trains in the vicinity of St. Valentin, Lower Austria, on October 25, 1939.

and in early 1939, a `` Fallen Figure '' of very ominous character, which concluded his abstract phase.

Faulkner's total works today, and in fact those of his works which existed in 1946 when Mr. Cowley made his comment, or in 1939, when Mr. O'Donnell wrote his essay, reveal no such simple attitude toward the South.

Early in 1939, Odilo Globocnik, the Gauleiter of Vienna, established SS headquarters for all of Poland.

Between 1935 and 1939 Letch and I made ten films together, each less successful, both artistically and commercially, than the one before it.

Under the 1939 Code this item was permitted to survive a tax-free reorganization in the Stanton Brewery case, but only over the dissent of Judge Learned Hand, who wrote the majority opinion in the Sansome case, a leading case requiring carryover of earnings and profits in a non-taxable reorganization.

W. E. Ford, for example, continued to supply data on the occurrence of minerals until his death in 1939.

The 1939 film Beau Geste is the only movie that features as many as four Academy Award winners for Best Actor in a Leading Role ( Gary Cooper, Ray Milland, Susan Hayward, Broderick Crawford ) prior to any of the actors receiving the Best Actor Award.

Symbolically, Marian Anderson ( a noted opera singer of her day ) sang a rendition of " America the Beautiful " on the steps of the Lincoln Memorial in 1939 after being refused use of Constitution Hall by the Daughters of the American Revolution because of her skin color.

* 1939 – 1945, the Second Battle of the Atlantic.

Subsequent formalizations were framed as attempts to define " effective calculability " or " effective method "; those formalizations included the Gödel – Herbrand – Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's " Formulation 1 " of 1936, and Alan Turing's Turing machines of 1936 – 7 and 1939.

William Burroughs went to a Korzybski workshop in the Autumn of 1939.

About 1939, he started to collect autographed cards of film stars.

Van Vogt's first published SF story, " Black Destroyer " ( Astounding Science Fiction, July 1939 ), was inspired by Voyage of the Beagle by Charles Darwin.

The 60-inch cyclotron at the Lawrence Radiation Laboratory, University of California, Berkeley, in August 1939.

In 1939, Orson Welles and the Mercury Players dramatized The Murder of Roger Ackroyd on CBS's Campbell Playhouse.

* 1890 – Anthony Fokker, Dutch aviation engineer ( d. 1939 )

* 1852 – Ferdinand von Lindemann, German mathematician ( d. 1939 )

* 1939 – The 1939-40 New York World's Fair opens.

* 1939 – NBC inaugurates its regularly scheduled television service in New York City, broadcasting President Franklin D. Roosevelt's N. Y. World's Fair opening day ceremonial address.

* 1939 – First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft.

* 1939 – Edward Patten, American singer-songwriter and producer ( Gladys Knight & the Pips ) ( d. 2005 )

In 1939 he met with Trappist monk Alexis Presse on a recommendation.

But in 1939, Robert Oppenheimer and others predicted that neutron stars above approximately three solar masses ( the Tolman – Oppenheimer – Volkoff limit ) would collapse into black holes for the reasons presented by Chandrasekhar, and concluded that no law of physics was likely to intervene and stop at least some stars from collapsing to black holes.

In 1933 Wells predicted in The Shape of Things to Come that the world war he feared would begin January 1940, a prediction which ultimately came true just four months early, when the Second World War broke out in September 1939.

Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer Arthur Edwin Kennelly ( 1861 – 1939 ) and the British physicist Oliver Heaviside ( 1850 – 1925 ).

Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer Arthur Edwin Kennelly ( 1861 – 1939 ) and the British physicist Oliver Heaviside ( 1850 – 1925 ).

In 1939, he predicted that Social Security would be under water by 1970, and insolvent by 1980.

If Linda had made landfall on California as predicted, it would have been the strongest storm to do so since a storm in 1939.

When Linda was predicted to turn towards the northeast, it was forecast to move ashore in Southern California as a weak tropical storm, which would have made Linda the first to do so since a tropical storm in 1939.

Armoured trains saw use during the 19th century in the American Civil War ( 1861 – 1865 ), the Franco-Prussian War ( 1870 – 1871 ), the First and Second Boer Wars ( 1880 – 81 and 1899 – 1902 ), the First ( 1914 – 1918 ) and Second World Wars ( 1939 – 1945 ) and the First Indochina War ( 1946 – 1954 ).

The notation was introduced in 1939 by Paul Dirac and is also known as Dirac notation, though the notation has precursors in Grassmann's use of the notation for his inner products nearly 100 years previously.

Trick-or-treating does not seem to have become a widespread practice until the 1930s, with the first U. S. appearances of the term in 1934, and the first use in a national publication occurring in 1939.

Moreover, the pact erased the legal distinction between war and peace since the signatories, having renounced the use of war began to wage wars without declaring them as evidenced by the U. S. intervention in Central America, the Japanese invasion of Manchuria in 1931, the Italian invasion of Abyssinia in 1935, the Soviet invasion of Finland in 1939, and the German and Soviet Union invasions of Poland.

The name had been in use since 1939 but was reverted in 1945.

In the summer of 1939 the Nazis themselves actually banned the continued use of the term in the press, ordering it to use expressions such as nationalsozialistisches Deutschland (" National Socialist Germany "), Grossdeutsches Reich (" Greater German Reich "), or simply Deutsches Reich ( German Reich ) to refer to the German state instead.

* 1939 – World War II: The Estonian military boards the Polish submarine in Tallinn, sparking a diplomatic incident that the Soviet Union will later use to justify the annexation of Estonia.

The submachine gun was invented during World War I ( 1914 – 1918 ), but the zenith of its use was World War II ( 1939 – 1945 ) when millions of weapons of this type were manufactured.

Trick-or-treating does not seem to have become a widespread practice until the 1930s, with the first U. S. appearances of the term in 1934, and the first use in a national publication occurring in 1939.

To get around the problem of the lack of bases outside of Germany and the shortage of Dithmarschen ships, Raeder had the Foreign Office in late 1939 negotiate secret agreements with Japan, Spain and the Soviet Union allowing German ships and submarines to use the ports of those nations to resupply, refuel and rearm.

The 1939 film was considered innovative because of its songs, special effects, and revolutionary use of the new Technicolor.

Carpal Tunnel Syndrome was most commonly noted in medical literature in the early 20th century but the first use of the term was noted 1939.

* 1939 – The BMW company's BMW 801 aviation radial engine pioneers the use of an early form of an engine control unit, the Kommandogerät.

It was her suggestion to use Antoine de Saint-Exupéry's 1939 book title as the organizing theme.

John Ford's use of Monument Valley as an expressive landscape in his films from Stagecoach ( 1939 ) to Cheyenne Autumn ( 1965 ) " present us with a mythic vision of the plains and deserts of the American West, embodied most memorably in Monument Valley, with its buttes and mesas that tower above the men on horseback, whether they be settlers, soldiers, or Native Americans ".

Other former cases at international courts between Belgium and other countries are — in chronological order — the Oscar Chinn Case of 1934 ( with the United Kingdom, the Borghgrave Case of ( 1937 ), the cases of the electricity company of Sofia ( with Bulgaria ) and of the " société commerciale de Belgique " ( with Greece ) of 1939, the case concerning the Barcelona Traction Company of 1970 ( with Spain ), the arrest warrant case of 2002 ( with the Democratic Republic of the Congo ) and the case concerning legality of use of force of 2004 ( with Serbia and Montenegro ).

Torquemada ( Edward Powys Mathers, 1892 – 1939 ), who set for The Saturday Westminster from 1925 and for The Observer from 1926 until his death, was the first setter to use cryptic clues exclusively and is often credited as the inventor of the cryptic crossword.

( 1892 – 1939 ), who called himself Torquemada in honour of the great Inquisitor — for compilers to use evocative pseudonyms.

Adolf Hitler gave Joseph Stalin free rein over these countries and he made immediate use of this to set up Soviet military bases in Estonia and Latvia in late 1939.

From there he and Gretl, with some assistance from Ludwig ( who acquired British nationality in 1939 ), managed to use family finances ( mostly held abroad ) and legal connections to attain non-Jewish status for their sisters.

The first attested use of the term sociolinguistics was by Thomas Callan Hodson in the title of a 1939 paper.