نتایج جستجو برای: deuterium compounds
تعداد نتایج: 235130 فیلتر نتایج به سال:
Remote Site?Selective Radical C(sp <sup>3</sup> )?H Monodeuteration of Amides using D <sub>2</sub> O
Site-selective incorporation of deuterium into biologically active compounds is high interest in pharmaceutical industry. We present a mild and environmentally benign metal-free method for the remote selective radical C?H monodeuteration aliphatic bonds various amides with inexpensive heavy water (D2O) as source. The uses easily installed N-allylsulfonyl moiety an N-radical precursor that gener...
Deuterium loading of palladium cathodes in Pons-Fleischmann type electrolytic cells has been observed to result in generation of excess heat on several occasions. Metallurgical examination of some of the electrodes showed extensive damage associated with deuterium loading. Surfaces have been found to be covered with large number of impurities. Initiation and sustaining these heat bursts, monito...
We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium (SD2). This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid ortho-deuterium as the source material. These measurements are performed utilizing a SD2 source coupled to a spallation source of neutrons, providing a demonstra...
Hydrogen/deuterium was implanted in ^100& silicon to passivate dangling bonds at the Si/SiO2 interface when a thin oxide is grown on implanted silicon substrate. It was observed that implantation energy and dose influence the interface passivation. Measured interface states at the Si/SiO2 interface suggest an isotope effect where deuterium implanted devices yielded better interface passivation ...
Based on the Volmer-Heyrovsky-Tafel mechanism, Frumkin adsorption and thermodynamic data of hydrogen (deuterium) absorption in Pd, effects of surface parameters on the hydrogen (deuterium) loading ratio into Pd in the hydrogen (deuterium) evolution reaction are discussed. There is a change of mechanism from the Volmer-Tafel route to the Volmer-Heyrovsky route when the current density rises, and...
Accurate values of the thermal conductivity and specific heat of deuterium are necessary to make high quality cryogenic laser fusion targets. Due to the difficulty of measuring these values at cryogenic temperatures, the “3ω” method is used. This involves passing an oscillating current through a platinum wire embedded in deuterium and measuring the third-harmonic voltage that results from the t...
A general theoretical model is described for the NMR spectra of mixtures of sterols and deuterium-labeled phospholipids. In the case of homogeneous membranes, the average quadrupole splittings are determined by equilibria between lipids in cholesterol-phospholipid complexes and lipids not in complexes. Chemical exchange of lipids between those in the free state and those in the complex state af...
The Pd/C-catalyzed efficient and regioselective hydrogen-deuterium (H-D) exchange reaction on the benzylic site proceeded in D2O in the presence of a small amount of H2 gas. The use of the Pd/C-ethylenediamine complex [Pd/C(en)] as a catalyst instead of Pd/C led to the efficient deuterium incorporation into the benzylic site of O-benzyl protective groups without hydrogenolysis. These H-D exchan...
On the Madison Symmetric Torus magnetic fusion plasma experiment, frozen pellet injection is an established method of depositing deuterium fuel into the core of the plasma. To freeze deuterium gas into pellets, the injector is cooled to 10 K with a cryogenic helium refrigerator. To exhaust residual frozen deuterium following injection of each pellet, the injector is warmed by resistive heating ...
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