81. Pieter Zeeman Chair In Amsterdam And C.V. Raman The correspondence between Raman and the Dutch Scientists pieter zeeman and JacobClay has been analysed to show that Raman was invited to take over the http://www.uni-oldenburg.de/histodid/publikationen/histodid80.html

Singh, Rajinder et.al.: Pieter Zeeman chair in Amsterdam and C.V. Raman Author(s) Singh, Rajinder Riess, Falk Title Pieter Zeeman chair in Amsterdam and C.V. Raman Date of Upload Article : Current Science 78 (2000), pp. 351-353., Current Science Association Keywords : C.V. Raman, P. Zeeman, Zeeman Effect PACS : 33.15.-e, 33.20.Fb, 33.20.Kf, 33.20.Sn, 33.20.Tp, 61.10.-i, 61.12.Bt, 95.30.-k, 01.75.+m, 01.65.+g, 01.70.+w Abstract The correspondence between Raman and the Dutch Scientists Pieter Zeeman and Jacob Clay has been analysed to show that Raman was invited to take over the Zeeman Chair at the University of Amsterdam. In the end he did not receive this prestigious position. The reasons for this will be illustrated. URL: http://www.ias.ac.in/currsci/feb102000/HISTORICALNOTES.PDF (application/pdf) This shadow-file was created by My Meta Maker 1.6.1 . Last Update: Tue Mar 9 0:43:48 2004

82. Selected Twentieth Century Works: Z zeeman, pieter, 18651935. Researches in magneto-optics, with special referenceto the magnetic resolution of spectrum lines, by P. zeeman. http://www.thebakken.org/library/books/20z.htm

Books and Manuscripts Selected Twentieth Century Works: Z Previous Page Zeeman, Pieter, Researches in magneto-optics, with special reference to the magnetic resolution of spectrum lines, by P. Zeeman. London, Macmillan, 1913. xiv, [1], 219 p. illus., diagrs., 8 plates. 22.5 cm. Lorentz and Zeeman shared the 1902 Nobel Prize in physics in recognition of their investigations of magnetism upon the phenomenon of radiation. This summary of the Zeeman Effect (the influence of magnetism on emission spectra) and related phenomena is dedicated to Faraday who had earlier shown that magnetic forces influenced the polarization of light. Zehnder, Ludwig Albert, Eine neue unsichtbare Strahlung. 2. Mitteilung, von L. Zehnder. Basel, E. Birkhauser, 1937. 1-[27] p. illus. 22.9 cm. Zehnder, a professor of physics at the University of Basel, details in this work the advances made in the field of chemical radiation and cytology. Zeiss, Carl, firm (Founded 1846). Mikrophotographische Apparate. 5. Ausg. [Jena] 1903. [8], 61, [1] p. illus. 27.3 cm. Provenance: Owner stamp, "Gustav Bucky".

83. Zeeman Atomic Absorption - What Does Zeeman Atomic Absorption Stand For? Definit Definition of zeeman Atomic Absorption in the list of acronyms provided by the zeeman Laser Scattering zeeman, (Erik) Christopher zeeman, pieter http://acronyms.thefreedictionary.com/Zeeman Atomic Absorption

Domain='thefreedictionary.com' word='ZAA' Your help is needed: American Red Cross The Salvation Army join mailing list webmaster tools Word (phrase): Word Starts with Ends with Definition subscription: Dictionary/ thesaurus Computing dictionary Medical dictionary Legal dictionary Financial dictionary Acronyms Columbia encyclopedia Wikipedia encyclopedia Hutchinson encyclopedia ZAA (redirected from Zeeman Atomic Absorption 0.01 sec. Page tools Printer friendly Cite / link Email Feedback Acronym Definition ZAA Zeeman Atomic Absorption Acronyms browser Full browser ZECSY ZED ZED-2 ZEDAT ... ZEE Zeeman Atomic Absorption ZEEP ZEF ZEFF ZEFIX ... Zeeman (crater) Zeeman Atomic Absorption Zeeman Atomic Absorption Spectroscopy Zeeman crater Zeeman effect Zeeman effect ... Zeer Uitgebreid Lager Onderwijs Word (phrase): Word Starts with Ends with Definition Free Tools: For surfers: Browser extension Word of the Day NEW! Help For webmasters: Free content NEW! Linking Lookup box ... Farlex, Inc. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.

84. Zeeman Atomic Absorption Spectroscopy - What Does Zeeman Atomic Absorption Spect Definition of zeeman Atomic Absorption Spectroscopy in the list of acronyms zeeman Laser Scattering zeeman, (Erik) Christopher zeeman, pieter http://acronyms.thefreedictionary.com/Zeeman Atomic Absorption Spectroscopy

Domain='thefreedictionary.com' word='ZAAS' Your help is needed: American Red Cross The Salvation Army join mailing list webmaster tools Word (phrase): Word Starts with Ends with Definition subscription: Dictionary/ thesaurus Computing dictionary Medical dictionary Legal dictionary Financial dictionary Acronyms Columbia encyclopedia Wikipedia encyclopedia Hutchinson encyclopedia ZAAS (redirected from Zeeman Atomic Absorption Spectroscopy 0.01 sec. Page tools Printer friendly Cite / link Email Feedback Acronym Definition ZAAS Zeeman Atomic Absorption Spectroscopy Acronyms browser Full browser ZECSY ZED ZED-2 ZEDAT ... ZEE Zeeman Atomic Absorption Spectroscopy ZEEP ZEF ZEFF ZEFIX ... Zeeman Atomic Absorption Zeeman Atomic Absorption Spectroscopy Zeeman crater Zeeman effect Zeeman effect Zeeman effect ... Zeerust Word (phrase): Word Starts with Ends with Definition Free Tools: For surfers: Browser extension Word of the Day NEW! Help For webmasters: Free content NEW! Linking Lookup box ... Farlex, Inc. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.

85. Pieter Zeeman Translate this page Pagina do Professor Carlos Fernandes resumos de biografias de personalidades dahistoria da humanidade premios nobel, cientistas, engenheiros, escritores, http://www.sobiografias.hpg.ig.com.br/PieterZe.html

Pieter Zeeman Hendrik Antoon Lorentz , efeito esse que se tornou conhecido como efeito de Zeeman Catharinus Forandinus Zeeman e sua esposa, Wilhelmina Worst Kamerlingh Onnes Hendrik Lorentz . Foi nomeado (1890) assistente de Lorentz, onde integrou a equipe de pesquisas sobre o efeito Kerr . Obteve seu doutorado (1893), e foi para Instituto F. Kohlrausch, em Estrasburgo, onde trabalhou um semestre com E. Cohn . Retornou a Leiden (1894) onde foi privaat-docent (1895-1897). Na Universidade de Leiden, orientado por seu professor Hendrick Lorentz , ele descobriu o efeito Zeeman teoria de Lorentz Johanna Elisabeth Lebret Foto copiada do site russo MAGNET: http://www.peoples.ru/science/physics/

86. Pieter Zeeman pieter zeeman. Hauptseite/Main Page.Deutsch. English. pieter zeeman. Erstellt am 30.10.2000, Zuletzt geändert am http://www.niester.de/p_natwis/zeeman/zeeman.html

Pieter Zeeman Hauptseite/Main Page Deutsch English Pieter Zeeman Erstellt am:

87. Zeeman Translate this page photo zeeman, pieter (1865-1943), niederländischer Physiker und Nobelpreisträger,bekannt für die Entdeckung des nach ihm benannten Effekts. http://www.katharinen.ingolstadt.de/physiker/zeeman.htm

Pieter Zeeman Zeeman, Pieter (1865-1943), niederländischer Physiker und Nobelpreisträger, bekannt für die Entdeckung des nach ihm benannten Effekts. Zeeman wurde in Zonnemaire geboren und studierte an der Universität Leiden, wo er später auch lehrte. Im Jahre 1900 wurde er als Professor für Physik an die Universität von Amsterdam berufen. Zeeman entdeckte 1896, daß sich die Spektrallinien einer Lichtquelle im starken Magnetfeld in mehrere polarisierte Komponenten aufspalten. Dieses Phänomen, das als Zeeman-Effekt bezeichnet wird, bestätigt die elektromagnetische Theorie des Lichtes. Zeeman teilte sich im Jahre 1902 mit dem niederländischen Physiker Hendrik Antoon Lorentz den Nobelpreis für Physik für die gemeinsame Forschung über den Einfluß des Magnetismus auf die Strahlung. Zurück zum Inhaltsverzeichnis

88. Pieter Zeeman Holandsky fyzik pieter zeeman se narodil 25. kvetna 1865 v Zonnemaire (mala vesnice pieter zeeman zemrel po kratke nemoci 9. rijna 1943 v Amsterodamu. http://converter.misto.cz/_MAIL_/fyzici/zeeman.htm

Prevody OnLine Fyzici Vzkazy ... Autor Pieter Zeeman Zpet Jednotka zeeman Nobelova cena spolu s H. A. Lorentzem za vyzkum vlivu magnetizmu na zareni. Presun webu Cely web conVERTER jsem v srpnu 2002 presunul. Dokument, ktery mate prave zobrazen, neni aktualizovan. Podivejte se na aktualizovanou stranku Pieter Zeeman Omlouvam se za pripadne potize. Jiri Bures Holandsky fyzik Pieter Zeeman se narodil 25. kvetna 1865 v Zonnemaire (mala vesnice na ostrove Schouwen v Holandsku) v rodine mistniho luteranskeho kneze. Od roku 1885 studoval na univerzite v Leidenu mj. u H. A. Lorentze (experimentalni fyzika) a H. Kamerlingh-Onnese (mechanika), ktery byl mj. v roce 1913 laureatem Nobelovy cena za fyziku. Od roku 1890 pusobil jako Lorentzuv asistent (v roce 1902 oba ziskali Nobelovu cenu za fyziku). V roce 1893 obhajil doktorat. V roce 1895 se ozenil s Johannou Elizabeth Lebretovou. Mel s ni syna a tri dcery. Roku 1896 popsal jev, kdy po zapnuti vnejsiho magnetickeho pole dochazi k tomu, ze ostre spektralni cary se stepi na vice prostorove blizkych spektralnich car. Zeeman tento jev vysvetlil jako interakci mezi magnetickym polem a magnetickym dipolovym momentem (souvisi s orbitalnim momentem). V pripade nepritomnosti vnejsiho magnetickeho pole ke stepeni spektralnich car nedochazi. Jev byl pozdeji pojmenovan Zeemanovym jevem - za objevy souvisejici s timto jevem obdrzel v roce 1902 Nobelovu cenu. Teoreticky byl jev rozpracovan

89. Zeen Definition Of Zeen In Computing Dictionary - By The Free Online Dictionary, zeeman Laser Scattering zeeman, (Erik) Christopher zeeman, pieter zeeman,pieter zeeman, pieter zeeman, pieter http://computing-dictionary.thefreedictionary.com/zeen

Domain='thefreedictionary.com' word='zeen' Your help is needed: American Red Cross The Salvation Army join mailing list webmaster tools Word (phrase): Word Starts with Ends with Definition subscription: Dictionary/ thesaurus Computing dictionary Medical dictionary Legal dictionary Financial dictionary Acronyms Columbia encyclopedia Wikipedia encyclopedia Hutchinson encyclopedia zeen 0.03 sec. Page tools Printer friendly Cite / link Email Feedback See zine Mentioned in Webzine zine Computing browser Full browser ZCAV ZCLV ZDBOp ZDNet ... Zed zeen Zen zenix ZENO ZENworks ... Zeeman, Pieter zeen Zeena Galatea LaVey Zeena LaVey Zeena Parkins Zeena Schreck ... Zeev Zrizi Word (phrase): Word Starts with Ends with Definition Free Tools: For surfers: Browser extension Word of the Day NEW! Help For webmasters: Free content NEW! Linking Lookup box ... Farlex, Inc. All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.

90. Pieter Zeeman Translate this page pieter zeeman. pieter zeeman. http://www.chemie.uni-bremen.de/stohrer/biograph/zeeman.htm

Pieter Zeeman

91. The Zeeman Effect The Dutch physicist pieter zeeman first observed it in 1896. The simplest is thesplitting up of one spectral line into three components called the Normal http://home.cern.ch/w/wadhwa/www/zeeman.html

Zeeman Effect A state of quantum number n breaks up into several substates when the atom is in a magnetic field, their energies are slightly more or slightly less than the energy of the state in the absence of the magnetic field. This phenomena leads to a ``splitting'' of individual lines into separate lines when atoms radiate in a magnetic field, with the spacing of the lines dependent on the magnitude of the magnetic field. The splitting up of these spectral lines of atoms within the magnetic field is called Zeeman Effect. The Dutch physicist Pieter Zeeman first observed it in 1896. The simplest is the splitting up of one spectral line into three components called the "Normal Zeeman Effect". To find the magnetic energy that an atom of magnetic quantum number m l when it is in a magnetic field is given by Following figure depicts the normal zeeman effect. Figure : Normal Zeeman Effect Exercise Using the Cadmium lamp as a specimen, investigate the splitting up of spectral lines using the the Fabry-Perot interferometer and self-made telescope. From your data you will calculate the magnitude of the Bohr magneton: Experimental Setup Figure : Experimental Setup Tips One of the outlet holes of the pole-shoes concidies with the iris diaphragm.

92. Encyclopedia: Pieter Zeeman Other descriptions of pieter zeeman. pieter zeeman (May 25, 1865 – October 9,1943) (pronounced zā m¤n) was a physicist who shared the 1902 Nobel Prize http://www.nationmaster.com/encyclopedia/Pieter-Zeeman

Supporter Benefits Signup Login Sources ... Pies Related Articles People who viewed "Pieter Zeeman" also viewed: Zeeman effect Alexander Prochorow Aleksandr Mikhailovich Prokhorov Gerardus 't Hooft ... Timeline of scientific discoveries What's new? Our next offering Latest newsletter Student area Lesson plans Recent Updates Vegeta Vasco da Gama Vainquer Teens VS System ... More Recent Articles Top Graphs Richest Most Murderous Most Taxed Most Populous ... More Stats Encyclopedia: Pieter Zeeman Updated 50 days 20 hours 42 minutes ago. Other descriptions of Pieter Zeeman Pieter Zeeman May 25 October 9 ) (pronounced zā'm¤n) was a physicist who shared the Nobel Prize in Physics with Hendrik Lorentz for his discovery of the Zeeman effect May 25 is the 145th day of the year in the Gregorian calendar (146th in leap years). ... 1865 is a common year starting on Sunday. ... October 9 is the 282nd day of the year (283rd in Leap years). ... 1943 is a common year starting on Friday. ... When stuff moves. ... 1902 was a common year starting on Wednesday (see link for calendar). ... Photographs of Nobel Prize Medals. ...

93. ZEEMAN Translate this page zeeman, pieter. Piero Gobetti Editore 2-10-1923, p. 120. (A. 2, n. 29, 1923) http://www.erasmo.it/liberale/testi/indici/zeeman.htm

ZEEMAN, Pieter Piero Gobetti Editore [2-10-1923, p. 120]. (A. 2, n. 29, 1923)

94. Nobel Prize In Physics 1902 Button Additional Information; pieter zeeman Button 1/2 of prize Button theNetherlands Button born 1865, died 1943 Button CA University of Amsterdam, http://www.slac.stanford.edu/library/nobel/nobel1902.html

Home About Contact "in recognition of the extraordinary service they rendered by their researches into the influence of magnetism upon radiation phenomena" Hendrik Antoon Lorentz 1/2 of prize the Netherlands born 1853, died 1928 CA - Leiden University , Leiden, the Netherlands AA - Leiden University WA - Leiden University Additional Information Pieter Zeeman 1/2 of prize the Netherlands born 1865, died 1943 CA - University of Amsterdam , Amsterdam, the Netherlands AA - Leiden University , Leiden, the Netherlands WA - Leiden University Additional Information Additional Information: Nobel e-Museum Prize in Physics 1902 Hendrik Antoon Lorentz Electromagnet image Return to Top Explanation of Institutional Affiliations: Current Affiliation (CA) The Laureate's current or last affiliation. Award Affiliation (AA) The institution(s) with which the Laureate was officially associated when s/he did the Nobel award work. Work Affiliation (WA) Where the actual Nobel work was performed. Particularly in recent years, work leading to experimental discoveries is often conducted at one of a few large physics laboratories in the world. Return to Top Content Owner: K. Sutton

95. ZNG Dicussion From Pieter Van Lierop On 2001-09-26 (www-zig@w3.org From Septembe pieter van Lierop Geac Discussion on the ZNGInitiative (Bull) zeeman ZNG will be unable to compete with XQL. http://lists.w3.org/Archives/Public/www-zig/2001Sep/0051.html

W3C home Mailing lists Public www-zig@w3.org ... September 2001 ZNG dicussion This message Message body Respond More options Related messages Next message Previous message Next in thread Replies From pvanlierop@geac.fr Date : Wed, 26 Sep 2001 09:40:48 +0200 Message-ID To : "' www-zig@w3.org '" < www-zig@w3.org Received on Wednesday, 26 September 2001 03:51:30 EDT This message Message body Next message Alan Kent: "Re: ZNG dicussion" Previous message William Moen: "US National Z3950 Profile draft specifications" Next in thread Alan Kent: "Re: ZNG dicussion" Reply Alan Kent: "Re: ZNG dicussion" Reply Robert Sanderson: "Re: ZNG dicussion" Reply Mike Taylor: "ZOOM - a complement to ZNG?" Reply Mike Taylor: "Re: ZNG dicussion" Maybe reply Pieter Van Lierop: "RE: ZNG dicussion" Maybe reply Robert Sanderson: "Re: ZNG dicussion" Maybe reply Gladwell, Kevin: "RE: ZNG dicussion" Maybe reply Gladwell, Kevin: "RE: ZNG dicussion" Mail actions respond to this message mail a new topic Contemporary messages sorted by date by thread by subject by author ... by messages with attachments Help How to use the archives Search in the archives This archive was generated by hypermail pre-2.1.9

96. Re: Z39.50 Character Encoding From Johan Zeeman On 2002-02-26 (www-zig@w3.org Fr From Johan zeeman joe.zeeman@tlcdelivers.com Date Tue, 26 Feb 2002 094028 0500 second time sending this - first time went to pieter only! http://lists.w3.org/Archives/Public/www-zig/2002Feb/0107.html

W3C home Mailing lists Public www-zig@w3.org ... February 2002 Re: Z39.50 character encoding This message Message body Respond More options Related messages Next message Previous message In reply to Next in thread ... Replies From joe.zeeman@tlcdelivers.com Date : Tue, 26 Feb 2002 09:40:28 -0500 Message-ID To : "Pieter Van Lierop" < pvanlierop@geac.fr a.sanders@mcc.ac.uk >, "zig" < www-zig@w3.org pvanlierop@geac.fr a.sanders@mcc.ac.uk >; "zig" < www-zig@w3.org zzaascs@irwell.mimas.ac.uk a.sanders@mcc.ac.uk http://copac.ac.uk/ Received on Tuesday, 26 February 2002 09:44:04 EST This message Message body Next message Mark Reichert: "Re: Z39.50 character encoding" Previous message Ray Denenberg: "Re: Z39.50 character encoding" In reply to Pieter Van Lierop: "RE: Z39.50 character encoding" Next in thread Mike Taylor: "Re: Z39.50 character encoding" Reply Mike Taylor: "Re: Z39.50 character encoding" Mail actions respond to this message mail a new topic Contemporary messages sorted by date by thread by subject by author ... by messages with attachments Help How to use the archives Search in the archives This archive was generated by hypermail pre-2.1.9

97. MSN Encarta - Zeeman, Pieter Altre risorse di Encarta. Cerca in Encarta zeeman, pieter http://it.encarta.msn.com/encyclopedia_761565277/Zeeman_Pieter.html

MSN Home My MSN Hotmail Shopping ... Migliora la tua esperienza con Encarta Cerca in Encarta Articolo riservato agli iscritti MSN Encarta Premium: Puoi consultare questo e altri 30.000 articoli, un atlante interattivo, un dizionario bilingue e altre risorse, effettuando l'iscrizione a MSN Encarta Premium per €29,95 all'anno. Per saperne di pi¹. L'articolo ¨ disponibile solo per gli utenti iscritti a MSN Encarta Premium. Gi  iscritto? Per accedere fare clic sul pulsante Accedi in alto a destra. Zeeman, Pieter Zeeman, Pieter (Zonnemaire 1865 - Amsterdam 1943), fisico olandese. Studi² all'universit  di Leida, dove fu docente fino a quando nel 1900 non divenne... Vuoi altri contenuti di Encarta? Iscriviti subito e avrai a tua disposizione: Pi¹ di 30.000 articoli Atlante dinamico Dizionario bilingue Approfondimenti Bibliografie Web Center Trova altre informazioni su Zeeman, Pieter Altre risorse di Encarta Cerca in Encarta Zeeman, Pieter © 2005 Microsoft Informativa sulla privacy di MSN Condizioni per l'utilizzo Pubblicit  Guida

98. Pieter Zeeman Holandský fyzik pieter zeeman se narodil v rodine luteránského teologa v roce 1865.Od roku 1885 studoval na univerzite v Leidenu pod vedením H. http://www.mujweb.cz/www/nobelfyzika/1902b.htm

Pieter Zeeman (25. kvìtna 1865 – 19. øíjna 1943) Nobelovu cenu získal v roce 1902 spoleènì s  H. A. Lorentzem za zkoumání vlivu magnetismu na záøení. Holandský fyzik Pieter Zeeman se narodil v rodinì luteránského teologa v roce 1865. Od roku 1885 studoval na univerzitì v Leidenu pod vedením H. Kamerlingha-Onnese a H. A. Lorentze a po ukonèení studia zde zùstal pracovat jako asistent. Od roku 1900 byl profesorem fyziky na univerzitì v Amsterodamu, kde se vìnoval pozorování spekter. V prùbìhu své dlouholeté vìdecké èinnosti vìnoval nejvìtší pozornost výzkumu vlivù magnetického pole na rùzné druhy záøení. V roce 1896 pøi tìchto pokusech narazil na jev, který byl na jeho poèest pojmenován Zeemanovým efektem. Podstata jevu spoèívá v tom, že pùsobením magnetického pole se spektrální èáry polarizovaného svìtla štìpí na více složek. V atomové teorii se tento efekt vysvìtluje tak, že magnetické pole nemìní tvar dráhy elektronù kolem jádra atomu, ale otáèí jeho rovinu. Teoreticky byl tento objev rozpracován Lorentzem a právì tato Lorentzova teorie vedla ke zjištìní stejného pomìru náboje a hmotnosti u nabitých atomárních èástic vysílajících spektrální èáry, èímž byl podán dùkaz existence elektronù. Mimo jiné Zeeman experimentálnì zkoumal dvojitý lom svìtla v elektrickém poli a v roce 1917 na torzním kyvadlu potvrdil zvláštní vlastnost gravitace, že odchylky dráhy dané setrvaèností, které vyvolává, jsou u všech tìles stejné.

99. Torinoscienza.it > Pieter Zeeman Translate this page Science Center Torino, Italia, Portale di divulgazione scientifica - ScienceCenter, Turin, Italy. http://www.torinoscienza.it/personaggi/apri?obj_id=43

100. Pieter Zeeman http://www.castfvg.it/zzz/ids/zeeman_pieter.html

PIETER ZEEMAN Pieter Zeeman (1865-1943) fu un fisico olandese noto in astronomia per la scoperta dell' effetto magneto-ottico che da lui prende il nome. Nato il 25 maggio 1865 a Zonnemaire, studiò a Leida (allora uno dei centri di eccellenza per la fisica) con due grandi fisici: Heike Kamerlingh Onnes e Heindrik Antoon Lorentz, del quale divenne assistente. Dal 1897 insegnò all'Università di Amsterdam e dal 1923 ne diresse l'Istituto di fisica. Vinse il Premio Nobel per la Fisica nel 1902 assieme al suo maestro Heindrik Antoon Lorentz, mentre Onnes lo vinse nel 1913, sempre per la fisica. Indice dei termini astronomici Homepage

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Page 5     81-100 of 104    Back | 1  | 2  | 3  | 4  | 5  | 6  | Next 20