The determination of microgram quantities of sulphide in biological materials

Several methods for the estimation of microgram quantities of sulphide in biological material and enzymatic reaction mixtures were investigated- The optimum conditions for separation of sulphide by isothermal distillation are given. The formation of méthylène blue is recommended for the spectrophotometric determination of sulphide; modifications are described to improve the reliability and sensitivity of the method.     

Molecular orbital studies on diazine mono and di N-oxides

Pariser-Parr-Pople, iterative extended Huckel, CNDO/2 and MINDO/2 methods have been applied to diazine mono and di N-oxides. Electronic transitions and chemical reactivity of these molecules are explained. Dipole moments, heats of formation and binding energy are calculated.     

Coordination properties of vic-isonitrosoimines in their copper (II) and palladium (II) complexes

Preparation and structural characterization of palladium (II) complexes of ligands III-V and copper (II) complexes of III are reported. The elemental analyses of the complexes show that the metal: ligand ratio is 1:2. The electrical conductance in acetone shows the non-electrolytic nature of the complexes. The diamagnetic character suggests a gross square-planar geometry for the palladium (II) complexes. Copper (II) complexes are paramagnetic with¼eff.～1·90 B.M. Spectral data suggest that in all the complexes the ligand coordinates to the metal (II) symmetrically through isonitroso-nitrogen and imine-nitrogen, forming a five membered chelate ring. Amine-exchange reactions of the complexes are discussed and compared on the basis of their structures.     

Two-parameter ω-technique for MO calculations

A two-parameter ω-technique for MO calculations is proposed. The parameters ω and ω′ are chosen empirically to obtain a good agreement between calculated and observed bond lengths. The method amounts to an inclusion of the effect of nearest-neighbour electronic repulsion integrals into the conventional ω-technique.     

Preparation and properties of potassium pentafluorodioxo-tungstate (VI) K3WO2F5 and potassium octafluoropentaoxo-ditungstate (VI) K6W2O5F8

The potassium salts of two new hepta coordinated oxyfluoro anions of tungsten (VI) are reported in this paper. The monomer, K₃WO₂F₅ was obtained from the aqueous solution while the dimer, K₆W₂O₅F₈ was isolated from alcohol. The absorption peak of K₆W₂O₅F₈ at 830 cm^-1 has been attributed to W-O-W link. The W-O-W angle is found to be 155° and the force constant is 4.44 mdyn/A°. The d values obtained from x-ray powder diffraction studies are given.     

Window region infrared radiation transfer through clouds and the sensitivity of cloud parameters to radiative effects

The effects due to the passage of i.r. radiation through clouds are predominantly due to the window region spectrum (between 8 and 13 μm). An approximation scheme is used to identify those parameters in the cloud model that determine the heating and cooling effects and the sensitivity of these effects to the variations in the parameters. The results show that the anomalously large heating/cooling effects predicted by the exact calculations are actually a consequence of the choice of a homogeneous liquid water content profile and that an adjustment in this profile results in a lessening of these effects. The radiative effects are also found to be dependent on the size distribution in a nontrivial fashion. In particular, it is found that the use of bimodal distributions, a characteristic feature of clouds with entrainment, results in a lowering of the heating and cooling effects, even with a homogeneous vertical profile, to values more realistic than those obtained with monomodal distributions.     

Multiple scattering measurements on high energy protons with long cell lengths

Scattering measurements on individual tracks and relative scattering measurements on pairs of tracks have been made in two stacks exposed to 6·2 and 5·7 BeV protons respectively from the Berkeley Bevatron. Spurious scattering was determined in these two stacks for cell lengths ranging from 1 mm. to 8 mm. In one stack the magnitude of spurious scattering was very low while in the other it was fairly high. Our results indicate that:

1. (a)
   Spurious scattering varies with cell lengtht, as t^x, wherex is about 0·8 fort = 1 mm. to 3 mm. and about 0·5 fort = 3 mm. to 8 mm.     

Spin degeneracy and conductance fluctuations in open quantum dots

The dependence of conductance fluctuations on parallel magnetic field is used as a probe of spin degeneracy in open GaAs quantum dots. The variance of fluctuations at high parallel field is reduced from the low-field variance (with broken time-reversal symmetry) by factors ranging from roughly 2 in a 1 microm (2) dot to greater than 4 in 8 microm (2) dots. The factor of 2 is expected for Zeeman splitting of spin-degenerate channels. A possible explanation for the larger suppression based on field-dependent spin-orbit scattering is proposed.     

Search for B --> tau(nu) and B --> K(nu)nu

We report results of a search for B-->tau(nu) in a sample of 9.7 x 10(6) charged B meson decays. We exclusively reconstruct the companion B decay to suppress background. We set an upper limit on the branching fraction B(B-->tau(nu))<8.4 x 10(-4) at 90% confidence level. We also establish B(B+/--->K+/-nu(nu))<2.4 x 10(-4) at 90% confidence level.