Melting and vaporization of salts in a U-LiCl-Li2O system

Summary The electrochemical reduction of uranium oxide in the treatment of spent nuclear fuel requires a characterization of the LiCl-Li₂O salt used as a reaction medium. Physical properties, melting and vaporization are important for the application of the salt and thus they have been investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG), respectively. Experimental data suggest LiCl and Li₂O compound formations, leading to a melting point depression of the LiCl and a co-vaporization of the LiCl-Li₂O salt.     

Intermolecular and intramolecular Diels-Alder cycloadditions of 3-ylidenepiperazine-2,5-diones and 5-acyloxy-2(1h)-pyrazinones

The 3-ylidenepiperazine-2,5-diones 16 and 39 and 5-acyloxy-2(1H)-pyrazinones 17 can serve as starting materials for the Diels-Alder reactions of alkenes and alkynes to the piperazine ring, under acidic conditions or in the presence of acetyl chloride, to afford tricyclic piperazine-2,5-diones 19, 20, 23-25, 27, 44, and 45. Intramolecular cycloadditions occur if 3-ylidenepiperazine-2,5-diones 30 and 32 are used as the starting materials. This procedure is a convenient path to bridged bicyclo[2.2.2]diazaoctane ring systems such as 31 and 33, the former being found in biologically active secondary mold metabolites, such as VM55599 (1) or brevianamide A (5), which have been isolated from various fungi. The synthesis of the indole compound 31 provided evidence for the proposed biochemical pathway with a Diels-Alder reaction as key step. Quantum chemical calculations have revealed that piperazinones with a cationic azadiene moiety are the most reactive species in Diels-Alder cycloadditions.     

Solid-phase synthesis of 4-biaryl-piperidine-4-carboxamides

A novel solid-phase synthesis of 4-biaryl-piperidine-4-carboxamides has been developed using FDMP resin with a carboxamide as the anchor point. With this approach, three points of diversity were incorporated into a GPCR-directed scaffold. Final products were obtained in good purity and yield.     

Superselection rules in quantum theory: Part I. A new proposal for state restriction violation

It is argued that preparation of a quantum state characterized by density operator not commuting with a superselection operatorQ does not by itself constitute an instance of superselection rule violation. It would, however, be an instance of state restriction violation. It is held that superselection rule violation is only possible with simultaneous observable and state restriction violations. It is shown that it is a priori conceivable to subdivide an ensemble whose satisfies[, Q] = 0 into subensembles whose density operators violate the state restrictions. The dynamics of the subdivision process is not considered.     

New information-theoretic foundations for quantum statistics

When the state of a physical system is not fully determined by available data, it should be possible nevertheless to make a systematic guess concerning the unknown state by applying the principles of information theory. The resulting theoretical blend of informational and mechanical constructs should then constitute a modern structure for statistical physics. Such a program has been attempted by a number of authors, most notably Jaynes, with seeming success. However, we demonstrated in a recent publication that the standard list of so-called mutually exclusive and exhaustive quantum states that is commonly employed by these authors is in fact not exhaustive. It follows that the information-theoretic foundations of quantum statistics must be reformulated. The present paper discusses the fundamental problems involved and establishes a format for the correct application of information theory to quantum mechanical situations.Work supported by a grant from Research Corporation.