Gridded Cross Field Tube

A triode crossed field tube has been operated as a high voltage on-off switch tube. A third, partially transparent (grid) electrode is interposed between the anode and cathode and electrically tied to the cathode by a grid leak resistor. High voltage is first applied to the anode and cathode; the magnetic field is then raised to the conduction level (~ 0.01 Tesla). Ignition does not occur because the magnetic field is too low in the grid-anode gap and the electric field is zero in the cathode-grid gap. Pulsing the grid positive relative to the cathode (~ 1 kV) then results in breakdown of the cathode-grid gap; plasma comunication between the two gaps then fully ignites the tube and closes the main power circuit. Grid ignition has been achieved at 50 kV as well as grid ignition followed by current interruption against 10 kV. These levels were limited by the use of a modified, laboratory tube and not by the physics of the technique.     

Chloride spinels: A new group of solid lithium electrolytes

The chloride spinels Li₂MCl₄ with M = Mg, Mn, Fe and Cd show very high lithium ionic conductivity in the solid state. The ionic conductivity in the compounds under investigation was established with the help of emf measurements. The specific conductivities measured by both frequency response analysis and the four probe ac method are 1.3 Ω^?1 · cm^?1 for Li₂CdCl₄, and about 0.9Ω^?1 · cm^?1 for Li₂MnCl₄, Li₂MgCl₄, and Li₂FeCl₄ at 773 K. There are several indications that the ternary chlorides become highly disordered at elevated temperatures. Thus the Arrhenius plots, i.e. In σ · T vs 1/T-curves, exhibit significant bends, the slopes below the transition temperature being considerably higher than those above.     

Die sterischen Bedingungen der Fragmentierungsreaktion III. Teil. Stereoisomere 4-, 5- und 7-Decahydrochinolyl-toluolsulfonate Fragmentierungsreaktionen, 16. Mitteilung

In a heterolytic fragmentation reaction of the type a-b-c-d-X → a - b + c = d + : X the geometry of the d - X bond and that of the electron-donating group a relative to the b - c bond are critical. This follows from a study of solvolysis rates and products of stereoisomeric 1-methyl-4-, -5- and -7-decahydroquinolyl p-toluenesulphonates in 80 Vol.% ethanol.     

Field Theory on Kappa-spacetime

A general formalism is developed, that allows the construction of field theory on quantum spaces which are deformations of ordinary spacetime. The symmetry group of spacetime is replaced by a quantum group. This formalism is demonstrated for the -deformed Poincaré algebra and its quantum space. The algebraic setting is mapped to the algebra of functions of commuting variables with a suitable -product. Fields are elements of this function algebra. As an example, the Klein-Gordon equation is defined and derived from an action.     

Bioorganometallic chemistry: biocatalytic oxidation reactions with biomimetic NAD/NADH co-factors and [Cp*Rh(bpy)H] for selective organic synthesis

The biocatalytic, regioselective hydroxylation of 2-hydroxybiphenyl to the corresponding catechol was accomplished utilizing the monooxygenase 2-hydroxybiphenyl 3-monooxygenase (HbpA). The necessary natural 1,4-dihydronicotinamde adenine dinucleotide (NADH) co-factor for this biocatalytic process was replaced by a biomimetic co-factor, N-benzyl-1,4-dihydronicotinamide, 1b. The interaction between the flavin (FAD) containing HbpA enzyme and the corresponding biomimetic NADH compound, N-benzyl-1,4-dihdronicotinamide, 1b, for hydride transfer, was shown to readily occur. The in situ recycling of the reduced NADH biomimic 1b from 1a was accomplished with [Cp*Rh(bpy)H](Cl); however, productive coupling of this regeneration reaction to the enzymatic hydroxylation reaction was not totally successful, due to a deactivation process concerning the HbpA enzyme peripheral groups; i.e., -SH or -NH₂ possibly reacting with the precatalyst, [Cp*Rh(bpy)(H₂O)](Cl)₂, and thus inhibiting the co-factor regeneration process. The deactivation mechanism was studied, and a promising strategy of derivatizing these peripheral -SH or -NH₂ groups with a polymer containing epoxide was successful in circumventing the undesired interaction between HbpA and the precatalyst. This latter strategy allowed tandem co-factor regeneration using 1a or 2a, [Cp*Rh(bpy)(H₂O)](Cl)₂, and formate ion, in conjunction with the polymer bound, FAD containing HbpA enzyme to provide the catechol product.     

A new approach to helical primary structures of four-membered rings: (P)- and (M)-tetraspiro[3.0.0.0.3.2.2.2]hexadecane

A new approach to helical primary structures of four-membered rings uses a cycloaddition of a trimethylenketeniminium salt to suitable tailored methylenecyclobutanes to assemble the desired carbon framework. The results are short and effective syntheses of (M)-trispiro[3.0.0.3.2.2]tridecane [(M)-5], and (P)- and (M)-tetraspiro[3.0.0.0.3.2.2.2]hexadecane [(P)- and (M)-24]. Unlike helices of three-membered rings, the specific rotation decreases, as the length of the helix increases.