Applications of PTFE foil as a sensor alpha-radiation

Zastosowanie elektretu w rozwiązaniu dozymetru wykorzystuje efekt kompensacji dodatniego ładunku zgromadzonego w sensorze (elektrecie) w wyniku oddziaływania promieniowania z materią. Jony ujemne, powstałe w wyniku działania promieniowania jonizującego wewnątrz komory jonizacyjnej, kompensują dodatni ładunek elektretu. Pomiar ładunku próbki elektretowej, zastosowanej jako sensor, przed ekspozycją, oraz bezpośrednio po, pozwalają ocenić stężenie czynnika wywołującego zagrożenie w badanym środowisku.This article presents PTFE electret elements for detection and measurement of α-emission. Negative ions produced inside the chamber are collected on the positively charged electret, causing a reduction of its surface charge. The measurement of the depleted charge during the exposure period is a measure of integrated ionization during the measurement period. The electret charge is read before and after the exposure using a specially built non-contact electret voltage. Radon is a colourless, odourless and chemically inert radioactive gas, occurring as a radioactive decay product of the element uranium,238U in a wide range of rocks and soils, and in building materials incorporating or manufactured from these. Radon concentrates in the built environment, the most significant isotope, 222Rn, decaying by α-emission (half-life 3.8 days) to 218Po and thence (3.05 min) to 214Po, themselves both α-emitters. Radon is now recognised to be the second largest cause of lung cancer in the after smoking. Electret elements for dosimetr made of PTFE foil, and were formed on the corona triode

Alkenes as Azido Precursors for the One-Pot Synthesis of 1,2,3-Triazoles Catalyzed by Copper Nanoparticles on Activated Carbon

A one-pot protocol for the synthesis of 1,2,3-triazoles has been developed starting from inactivated alkenes and based on two click reactions: the azidosulfenylation of the carbon–carbon double bond and the copper-catalyzed azide–alkyne cycloaddition (CuAAC). High yields of the β-methylsulfanyl triazoles have been attained using CuNPs/C as catalyst, with other commercial copper catalysts being completely inactive. The versatility of the methylsulfanyl group has been demonstrated through a series of synthetic transformations, including direct access to 1-vinyl and 4-monosubstituted triazoles.Spanish Ministerio de Economía y Competitividad (MINECO; CTQ2007-65218, CTQ2011-24151 and Consolider Ingenio 2010-CSD2007-00006), the Generalitat Valenciana (GV; PROMETEO/2009/039), and Fondo Europeo de Desarrollo Regional (FEDER)

Metal-free coupling of saturated heterocyclic sulfonylhydrazones with boronic acids

The coupling of aromatic moieties with saturated heterocyclic partners is currently an area of significant interest for the pharmaceutical industry. Herein, we present a procedure for the metal-free coupling of 4-, 5-, and 6-membered saturated heterocyclic p-methoxyphenyl (PMP) sulfonylhydrazones with aryl and heteroaromatic boronic acids. This procedure enables a simple, two-step synthesis of a range of functionalized sp2−sp3 linked bicyclic building blocks, including oxetanes, piperidines, and azetidines, from their parent ketones. ■ INTRODUCTIO

Research data supporting: Iterative reactions of transient boronic acids enable sequential C-C bond formation

NMR filesThis record supports 'Iterative reactions of transient boronic acids enable sequential C-C bond formation', which has been published in Nature Chemistry.This work was supported by the EPSRC [grant numbers EP/K009494/1 and EP/M004120/1]