Development of an apparatus for obtaining molecular beams in the energy range from 2 to 200 eV

The formation and detection of molecular beams obtained by charge exchange from a low-energy ion source is discussed. Dispersion in energy of the ion source was measured and problems concerning detection of neutral beams were studied. Various methods were used, specifically secondary electron emissivity of a metallic surface and ionization of a gas target with a low ionization voltage. The intensities of neutral beams as low as 10 eV are measured by a tubular electron multiplier and a lock-in amplifier

Rediscovering Renaissance Recipes: Digital Presentation for a 16th Century Text

This project seeks to create a web-based system for working with a French text from 1509, Platine en francoys, which has been transcribed into an XML (Extensible Markup Language)-based file format using the conventions of TEI. Through incorporation of several web technologies such as NodeJS, the application provides a section by section navigation capability that allows versions of the text to be seen in multiple configurations. The options include a side-by-side presentation mode that allows for easy compare/contrast of the original versus a regularized spelling or other variants. A facsimile-focused view is also planned, along with tools leveraging the specialized markup and focused searches on non-recipe text, recipes, and ingredients. It is expected that these features will allow for a deeper understanding of the text as well as function as a foundation for future development work as part of the ongoing cross-disciplinary computing/language collaboration efforts

Plemeniti metali

Rutenij, rodij, iridij, osmij, paladij i platina nazivaju se platinskim metalima, a zajedno sa srebrom i zlatom čine skupinu plemenitih metala. Iako se ovi metali odlikuju kemijskom inertnošću, oni sami i njihovi spojevi nalaze razne primjene, pogotovo u nanokemiji budući da su se posljednjeg desetljeća snažno razvili analitički alati. Prema gustoći, ti se metali dijele na lake platinske metale (rutenij, rodij i paladij) čija gustoća iznosi oko 12 g cm-3 te teške (osmij, iridij i platina) čija je gustoća veća od 21 g cm-3. U prirodi se nalaze u malim koncentracijama i često u slitinama što predstavlja problem prilikom izolacije. Plemeniti metali mogu se nalaziti u velikom broju oksidacijskih stanja, čak i negativnim poput platine i zlata. Za sada je pronađen spoj u kojem je metal u oksidacijskom stanju +VIII, ali postoje teorijski dokazi o postojanju spoja s metalom u oksidacijskom stanju stanju +IX. Također, otkriveni su i spojevi s metal-metal vezama, u čemu prednjače zlato i platina. Jedno od najzanimljivijih otkrića jest nastajanje kompleksnog spoja zlata(II) s atomima ksenona. U kemiji plemenitih metala, najviše su istraženi halogenidi. Plemeniti metali češto rade koordinacijske spojeve, odnosno, spojeve koji sadrže središnji metalni atom koji je okružen ligandima. Najčešće geometrije takvih spojeva su kvadratna, tetraedarska i oktaedarska

DENSITÉ DES NIVEAUX DE BASSE ÉNERGIE ET INSTABILITÉS DE SURFACE DANS LES NOYAUX LOURDS DE TRANSITION

Une analyse statistique des niveaux nucléaires de Au, Pt, Hg a été réalisée avec la méthode d'Ericson. Les distributions expérimentales du nombre de niveaux d'or impair sont comparées aux distributions théoriques correspondant aux modèles vibrationnels (Alaga, Kisslinger-Sorensen) et rotationnels (Stephens, Meyer-ter-Vehn). Le modèle d'Alaga donne la description la plus complète des niveaux de 193,195Au et s'accorde avec la partie inférieure de la distribution de haute énergie de Gilbert-Cameron (déduite du modèle statistique et des données de capture neutronique). La méthode d'Ericson révèle d'autres aspects intéressants des isotopes de Pt et Hg (p. ex. dépendance entre la densité des niveaux et la forme des noyaux ou des corrélations de paires, évidence pour des transitions de phase). En conséquence, cette méthode est un outil approprié pour l'orientation des recherches expérimentales aussi bien que théoriques des noyaux de transition