Reversible hydrogen-storage functions for mixtures of Li3N and Mg3N2

The hydriding and dehydriding reactions occurring in mixtures of lithium and magnesium nitrides (Li₃N and Mg₃N₂) were investigated for the first time in fixed composition ratios. A mixture of Li₃N–20 at.%Mg₃N₂ after heat treatment at 833 K was hydrogenated at 523 K in 35 MPa according to the following overall reaction: 4Li₃N+Mg₃N₂+12H₂ 12LiH+3Mg(NH₂)₂. This reaction is one of the candidates for reversible hydrogen-storage functions in which 9.1 mass% of hydrogen can be stored in the solid state. PACS 81.05.Zx; 71.20.Ps; 82.30.-b     

A facile synthesis of pyrazole-5-sulfonamide derivatives

The reaction of the 5-unsubstituted pyrazoles 2a-k with lithium diisopropylamide or n-butyllithium gave intermediary 5-lithiopyrazoles, whose reaction with sulfur dioxide afforded the lithium pyrazole-5-sulfinates 3a-k . Subsequent reaction of 3a-k with N-chlorosuccinimide followed by ammonolysis provided the pyrazole-5-sulfonamides 5a-k .     

Determination of synthetic food dyes by capillary electrophoresis

A method for the determination of synthetic tar dyes used as food additives using capillary electrophoresis with photodiode-array detection was investigated. The dyes Erythrosine (R-3), Phloxine (R-104), Rose Bengal (R-105), Acid Red (R-106), Amaranth (R-2), New Coccine (R-102) and Allura Red AC (R-40) were separated on a capillary column (50 cm × 75 μm I.D.) and identified from the absorbance spectra of each peak. The electrophoresis buffer used was a mixture of 25 mM sodium phosphate buffer and 25 mM sodium borate buffer (1:1) (pH 8.0) containing 10 mM sodium dodecyl sulfate (SDS). Substitution of β-cyclodextrin for SDS in the electrolyte buffer was effective for the separation of R-2 and R-102. This modified method could be employed as an additional assay method for these two dyes.     

The impact of an intermediate temperature buffer on the growth of GaN on an AlN template by hydride vapor phase epitaxy

The present study focused on the effect of an intermediate-temperature (IT; ∼900 °C) buffer layer on GaN films, grown on an AlN/sapphire template by hydride vapor phase epitaxy (HVPE). In this paper, the surface morphology, structural quality, residual strain, and luminescence properties are discussed in terms of the effect of the buffer layer. The GaN film with an IT-buffer revealed a relatively lower screw-dislocation density (3.29×10⁷ cm⁻²) and a higher edge-dislocation density (8.157×10⁹ cm⁻²) than the GaN film without an IT-buffer. Moreover, the IT-buffer reduced the residual strain and improved the luminescence. We found that the IT-buffer played an important role in the reduction of residual strain and screw-dislocation density in the overgrown layer through the generation of edge-type dislocations and the spontaneous treatment of the threading dislocation by interrupting the growth and increasing the temperature.     

A bound for the number of different basic solutions generated by the simplex method

In this short paper, we give an upper bound for the number of different basic feasible solutions generated by the simplex method for linear programming problems (LP) having optimal solutions. The bound is polynomial of the number of constraints, the number of variables, and the ratio between the minimum and the maximum values of all the positive elements of primal basic feasible solutions. When the problem is primal nondegenerate, it becomes a bound for the number of iterations. The result includes strong polynomiality for Markov Decision Problem by Ye (http://www.stanford.edu/~yyye/simplexmdp1.pdf, 2010) and utilize its analysis. We also apply our result to an LP whose constraint matrix is totally unimodular and a constant vector b of constraints is integral.     

Microsphere manipulation using ferroelectric liquid crystals

We propose a strategy for a micromanipulation method using SSFLC (surface stabilized ferroelectric liquid crystals). By adjusting the frequency of the applied ac electric field, the surface layers that cannot follow an applied ac electric field are constructed in SSFLC. In addition, by applying a sawtooth wave voltage, net flow along the smectic layer is generated. The flow direction is reversed by changing the polarity of the sawtooth wave. Consequently, the particles dispersed in SSFLC can be driven bidirectionally along the smectic layer. The particle velocity depends on the temperature, amplitude, and frequency of the applied voltage.     

Synthesis of 5-chloropyrazoles by chlorodediazoniation with sulfur dioxide

A facile synthesis of 5 -chloropyrazoles 4a-e from 5 -aminopyrazoles 2a-e via diazotization followed by chlorodediazoniation is described. A new application of sulfur dioxide as a catalyst was demonstrated to be the best for the chlorodediazoniation of diazonium chlorides 3a-e .