The microstructures of laser-alloyed Ni-Ta surface layers

Evaporated thin tantalum films on single and polycrystalline nickel have been laser surface alloyed using either continuous-wave CO₂ or Q-switched Nd-YAG radiation. In the case of the continuous-wave laser, surface alloys contain amorphous tantalum-rich regions, intermediate polycrystalline bands of TaNi, and an underlying Ni(Ta) solid solution. In the Q-switched laser case, a much more laterally uniform amorphous phase with approximately equal atomic fractions of nickel and tantalum is found, with little evidence of polycrystalline intermetallics.In situ annealing with the electron beam of the microscope results in formation of microcrystallites, predominantly nickel.     

Extremely low-loss 1.5%-/spl Delta/ 32-channel athermal arrayed-waveguide grating multi/demultiplexer

A silica-based 1.5%-/spl Delta/ 100 GHz-spacing 32-channel athermal arrayed-waveguide grating (AWG) with compact size and extremely low insertion loss is described. By reducing the fibre coupling loss and the excess loss in a silicone-filled groove, an insertion loss of 1.3 dB was achieved with this athermal AWG.     

Continuous-wave lasing of single-mode metamorphic quantum dot lasers for the 1.5-μm spectral region

Lasers based on InAs/InGaAs quantum dots grown on metamorphic (In,Ga,Al)As layers deposited by MBE on GaAs substrates exhibited emission near 1.5 μm with a differential quantum efficiency of about 50%. The narrow-stripe lasers operate in a single transverse mode and withstand continuous current density above 20 kA cm^?2 without significant degradation. A maximum continuous-wave output power of 220 mW is obtained. Neither current nor beam filamentation was observed up to the highest pumping levels.     

Efficient data processing and quantum phenomena: Single-particle systems

We study the relation between the acquisition and analysis of data and quantum theory using a probabilistic and deterministic model for photon polarizers. We introduce criteria for efficient processing of data and then use these criteria to demonstrate that efficient processing of the data contained in single events is equivalent to the observation that Malus' law holds. A strictly deterministic process that also yields Malus' law is analyzed in detail. We present a performance analysis of the probabilistic and deterministic model of the photon polarizer. The latter is an adaptive dynamical system that has primitive learning capabilities. This additional feature has recently been shown to be sufficient to perform event-by-event simulations of interference phenomena, without using concepts of wave mechanics. We illustrate this by presenting results for a system of two chained Mach-Zehnder interferometers, suggesting that systems that perform efficient data processing and have learning capability are able to exhibit behavior that is usually attributed to quantum systems only.     

Effect of nisin on the storage of sous vide processed Korean seasoned beef

Seasoned beef called Jangzorim in Korea is produced by boiling in soy sauce, and is a popular food in Korea. The aim of this study is to evaluate the microbial safety and physical qualities of sous vide processed seasoned beef, and the effect of nisin during storage. Sous vide processed packages with or without nisin (100 IU or 500 IU) were stored at 4 °C or 25 °C for 60 days, and samples measured for quality at regular intervals throughout this storage period. In the case of 25 °C storage, the number of mesophilic microorganisms in seasoned beef packages without nisin increased markedly, but with nisin there was no observed increase. Psychrotrophic microorganisms, anaerobic microorganisms, and B. cereus cells showed similar trends, although C. perfringens was not detected in all samples. At 25 °C storage, changes in the cutting force of packages containing nisin showed no significant change, packages without nisin decreased markedly. The colour of packages without nisin showed a drastic decrease in lightness (‘L’) while no changes were observed in packages with nisin.     

Processes of the Collision Interaction between Ceramic Particles Being Crushed in a Circulation Pneumatic Crusher

A new circulation pneumatic crusher capable of producing submicron powders of refractory materials is presented. A mathematical model is constructed for the dynamic breaking of ceramic macroparticles. This model allows the basic laws of shock-wave crushing in the circulation pneumatic apparatus to be analyzed.__________Translated from Teoreticheskie Osnovy Khimicheskoi Tekhnologii, Vol. 39, No. 3, 2005, pp. 327–333.Original Russian Text Copyright © 2005 by Belov, Biryukov, Roslyak, Yugov, Afanas’ev.     

Preparation and Characterization of Novel Polyimides from 2,6-bis[1-(p-dimethylaminophenylimino)ethyl] pyridine for the Selective Extraction of some Metals

Summary A group of new polyimides has been prepared by solution condensation of 2,6-bis[1-(p-dimethylaminophenylimino)ethyl] pyridine containing pendant NMe₂ units and various dianhyrides in N-methylpyrrolidone (NMP). The tridentate (N-N′-N) pydim ligands were prepared by Schiff-base condensation of 2,6-diacetylpyridine and 4-dimethylaminoaniline in the presence of formic acid as catalyst. These polymers were investigated for their extraction capabilities for Zn(II), Mn(II), Cu(II), Cd (II) and Ni(II) and at different pH. Under different conditions enhanced selectivity was observed. Up to 98% quantitative recoveries were observed for all metals.     

Electrocatalysis of chlorine evolution on different materials and its influence on the performance of an electrochemical reactor for indirect oxidation of pollutants

Two different Ti/Pt–Ir materials (commercial and home made) and Ti/PdO + Co₃O₄ were investigated for their electrocatalytic properties versus Cl₂ evolution reaction. The materials were used in a batch electrochemical reactor to treat biologically recalcitrant di-azo compound. An electrochemically driven oxidation, mediated by a Cl₂/Cl⁻ couple, proved efficient for destruction of this complex organic molecule, causing cleavage of the conjugated double bonds and destruction of unsatured bonds. Both Ti/Pt–Ir materials performed well; lower kinetics obtained with the Ti/PdO + Co₃O₄ anode was caused by adsorption of the model compound, evidenced in preliminary voltammetric measurements. The dye oxidation reaction followed the second order kinetics with partial orders in the model compound and (time varying) chlorine concentrations equal to one. Specific energy consumption of 3.12 kWh m⁻³ proved the process more economic than the homogeneous phase oxidation.     

The focusing magnetic resonance system with a new type of supersonic atomic beam source

A focusing magnetic resonance system (MRS) with a new type of supersonic atomic - and molecular - beam source is suggested. The beam sources used in the MRS are discussed and the main operation principles of the suggested supersonic beam source as well as the advantages of this type of source over the rest are shown. An optimization procedure for the magnetic resonance system with the effect of the finite source size taken into account is considered. Numerical results are given and analyzed. The MRS with the new type of beam source possesses higher transmission with low background and is simpler and cheeper in construction as compared to the conventional systems.