Sur la possibilité d'une fluorescence cométaire excitée par la raie d'émission Lyman alpha-solaire

in Annales d'astrophysique (1957), 20

One may Wonder whether the solar emission line at Lyman α may not excite a fluorescence in cometary molecules. The authors show that no evidence for such a fluorescence is found at the present time.

Sur la pratique de la localisation implicite dans le Dictionnaire de l'Ouest-wallon d'Arille Carlier

in Travaux de linguistique et de philologie (1997), 35-36

Sur la présence des bandes d'absorption de AI H dans le spectre du disque solaire

in Bulletin de la Société Royale des Sciences de Liège (1934)

Sur la présence simultanée des bandes du carbone et de l'oxyde de titane dans les taches solaires

in Bulletin de la Classe des Sciences. Académie Royale de Belgique (1933), 19

Sur la proportion de carbone et de l'hydrogène contenue dans les schistes houillers : Contribution à l'étude de la formation de la houille

in Bulletin de la Société Chimique de Paris (1888), XLIX

Sur la rationalité dans les Idées I de Husserl

in Broze, M.; Decharneux, B.; Delcomminette, S. (Eds.) All’eu moi katalexon... "Mais raconte-moi en détail…" (Odyssée, III, 97): Mélanges de philosophie et de philologie offerts à Lambros Couloubaritsis (2008)

Sur la réaction de l'iode avec le sulfite acide de sodium

in Bulletin de la Société Chimique de Paris. 3e série (1891), V

Sur la réalisation d'un liquide optiquement vide

in Recueil des Travaux Chimiques des Pays-Bas et de la Belgique. 2e série (1899), XVIII

Spring, W. Recueil des Travaux Chimiques des Pays-Bas (1899), 18, 153-68; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). Tyndall has assumed that ... [more ▼]

Spring, W. Recueil des Travaux Chimiques des Pays-Bas (1899), 18, 153-68; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). Tyndall has assumed that when a beam of light passes through a gas its path is made evident by the illumination of minute solid or liquid particles present as impurities. Lallemand, however, from experiments with carefully distilled liquids, concluded that the illumination of a fluid medium by light is a specific property of the medium, and that each medium has a certain "coefficient of illumination", dependent on its nature. The author now shows that, although it is impossible to obtain a truly transparent liquid (that is, one which is not rendered luminous by the passage of a beam of light) by distillation or filtration, liquids can be rendered optically pure by means of a current of electricity; on passing, for example, a current through water containing a small quantity of silica or ferric hydroxide in suspension, the suspended matter is deposited at the cathode, and carries with it the minute particles which render the water capable of being illuminated. The same result is also obtained by adding clear lime water to a solution of silicic acid, and leaving the precipitate to subside in a stoppered vessel; on examining the liquid in a beam of light, care being taken that the vessel is not opened, it is found to be perfectly transparent. The subsidence of other gelatinous precipitates, such as the hydroxides of iron, aluminium, and zinc, from water renders the latter non-illuminable; the subsidence of crystalline precipitates, however, such as barium sulphate or calcium oxalate, gives no such result. It thus appears probable that the minute suspended particles can only be removed by being surrounded, during the precipitation, with a heavy, gelatinous envelope. The filtration of water through a layer of a gelatinous precipitate, out of contact with the air, renders it transparent; but if filtered in contact with air, this result is not obtained. The reason why distillation fails to yield transparent liquids is thus made evident. In the case of organic liquids, the author has not obtained such definite results; the subsidence of gelatinous precipitates from organic liquids is, as a rule, very incomplete, so that optical transparency cannot generally be obtained. It appears probable also, that many organic liquids become luminous on the passage of a beam of light, owing to fluorescence. The particles which are rendered luminous in water by a beam of light appear to consist largely of organic matter, but luminescence is also due to minute bubbles of gas; this is made clear by the increased illumination which occurs when the pressure in the space above the water is diminished, and by the fact that optically transparent water is rendered luminescent by passing air through it. Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved. [less ▲]

Sur la régulation de la température chez les animaux à sang chaud

in Archives Internationales de Physiologie (1913), XIII

Sur la représentation des modes rigides dans la formulation SAMCEF des problèmes hydro-élastiques

Report (1990)

A frequently asked question is to know if the SAMCEF formulation of hydro-elastic problems allows a correct representation of the rigid body modes. In fact, it is current to analyse the free-free ... [more ▼]

A frequently asked question is to know if the SAMCEF formulation of hydro-elastic problems allows a correct representation of the rigid body modes. In fact, it is current to analyse the free-free vibrational problem, and some people were surprised to loose rotational rigid body modes. The purpose of the present report is to enlighten this point. [less ▲]