Schmelzlinienbestimmungsmodell zur vergleichenden Leistungsbeurteilung von Hochofenperioden

Vergleich von Hochofenbetriebsergebnissen mittels Leistungs-Faktor-Definition. Bestimmung der Lage und Form der Schmelzlinie im Hochofen durch Betriebsdaten. Wärmeeinbringen durch Blasform und deren Übertragung durch Konvektion und Strahlung. Einfluß der Wärmebedingungen im Unterofen auf die Lage der Schmelzlinie. Vergleich und Überprüfung der Modellprofile durch Betriebsmessungen. Einfluß verschiedener Unterofenparameter auf Hochofenbetrieb und Schmelzlinie. Schmelzgeschwindigkeit bei W- und ∧-Profilen in Abhängigkeit der Strahlungstemperatur. Untere kritische Höhenlage der Schmelzlinie und dynamisches Verhalten der Schmelzlinie.     

A note on upwinding and anisotropic balancing dissipation in finite element approximations to convective diffusion problems

In one dimension, Petrov—Galerkin nonsymmetric weighting for the convective diffusion equation can be interpreted as an added dissipation. The addition of an appropriate amount of dissipation can therefore give the same oscillation-free solutions as the ‘unwinding’, Petrov—Galerkin, finite element methods. The ‘balancing dissipation’ is optimally chosen so that excessive dissipation does not occur. A scheme is presented for extending this approach to two-dimensional problems, and numerical examples show that the new method can be used with improved computational efficiency.     

Polymer film-type channel electron multipliers: Their characteristics and comparison with bulk-type flexible multipliers

Polymer film-type channel electron multipliers (CEMs) were developed and their characteristics investigated in comparison with bulk-type flexible CEM. As film-type CEMs, a paint-coating-type CEM and a solvent-etching-type CEM were fabricated. The paint-coating-type CEM is made by coating a “paint” which is prepared by dissolving in a solvent an electronically conductive polymeric composition having a high secondary electron emission yield. Up to the present study the mean gain of the film-type CEM, in spite of the lower resistivity of the dynode, seems to be slightly more dependent on the count rate than that of the bulk-type CEM made of the same material. However, the convenience of fabricating the dynode film by coating the dynode-forming paint on the internal surface of any shaped tube or a flexible polymer tube would overcome the slight disadvantage mentioned above.     

Determination of benzimidazole anthelmintics in livestock foods by HPLC

A simple and rapid liquid chromatographic method was developed for the simultaneous determination of twelve benzimidazole anthelmintics in livestock foods using reversed-phase high-performance liquid chromatography with photodiode array detection (PDA). A sample was homogenized with acetonitrile and n-hexane, and centrifuged. The acetonitrile phase was isolated and evaporated. The residue was dissolved in 0.1 mol/L carbonate buffer solution (pH = 9.1), sonicated, and then subjected to clean-up on a Bond Elut LRC-C18 cartridge. The benzimidazole compounds were separated isocratically on a Capcell Pak C18 UG 120 (5 microns, 150 x 4.6 mm i.d.) column and detected by PDA at 295 and 313 nm. Mixtures of acetonitrile and 0.05 mol/L ammonium acetate in mixing ratios of (20:80) and (40:60) were used as the mobile phase, and the flow-rate was 1.0 mL/min at 40 degrees C. The mean recoveries (n = 3) from 0.1-0.5 microgram/g added samples were 72.6-97.2% with coefficients of variation of 0.3-8.5%. The detection limits were 0.01-0.05 microgram/g.     

Gene expression within cell-sized lipid vesicles

Functional protein synthesis was observed in cell-sized lipid vesicles following encapsulation of a gene-expression system. Expression of rsGFP (red-shifted green fluorescent protein) within individual vesicles was observed by fluorescence microscopy. Interestingly, at the early stage of the reaction, the expression efficiency inside the vesicle was remarkably higher than that in the solution outside. The synthesized rsGFP in individual vesicles is safe from attack by proteinase K added to the external aqueous solution. Studies on cell-sized vesicles expressing protein should contribute to a fundamental understanding of certain aspects of living systems and will be useful for practical applications, such as the construction of microreactors.     

Three-Dimensional Numerical Simulation of Helically Propagating Combustion Waves

In the present paper, by using a mathematical model for self-propagating high-temperature synthesis, we reveal the three-dimensional structure of so-called spin combustion wave on the inside of cylindrical sample. It is shown that an isothermal surface of regular spin combustion wave has some wings of which number is the same as that of reaction spots on the cylindrical surface and that the isothermal surface with helical wings rotates down with time. Because of this propagating pattern, in this paper, we adopt the more suitable term helical wave. We also obtain the following existence conditions of a helical wave: If physical parameters are set so that a pulsating wave exists stably for the one-dimensional problem, then a helical wave takes the place of a pulsating wave when the radius of cylindrical sample becomes large.     

Intermetallic compound formation between lead-free solders (Sn) and Cu or Ni electrodes

A kinetic model based on the principle of maximum degradation rate of the total system free energy, MDR law using thermodynamic data, is proposed and successfully applied to the selection of the first intermetallic compound (IMC) phase in Cu/Sn and Ni/Sn diffusion couples. The first phases predicted with this model for Cu/Sn and Ni/Sn are Cu₆Sn₅ and Ni₃Sn₄, respectively, resulting in good agreement with experimental observations.     

Analytical Model for Redistribution Profile of Ion-Implanted Impurities During Solid-Phase Epitaxy

We evaluated the redistribution profiles of ion-implanted impurities during solid-phase epitaxy using Rutherford backscattering spectrometry (RBS). RBS data revealed that the As concentration changes only near the moving amorphous/crystal interface. We derived an analytical model for the redistribution profiles using a segregation coefficient m between amorphous and crystalline Si, introduced a parameter of reaction length l that is the distance where impurities were exchanged, and obtained good agreement with experimental data with an m value of 3 and an l value of 1 nm for As. Furthermore, we applied our model to P and B redistribution profiles and obtained good agreement with corresponding m value of 4 and l value of 1 nm for P and m value of 0.3 and l value of 1 nm for B     

10-GHz 8.7-ps Pulse Generation From a Single-Mode Gain-Switched AlGaAs VCSEL at 850 nm

We have successfully generated a 10-GHz 8.7-ps pulse train at 850 nm by using a gain switching technique with a high-speed AlGaAs-based vertical-cavity surface-emitting laser (VCSEL). The VCSEL, which operates in a single transverse mode by employing an aluminum oxide aperture, has a modulation bandwidth of 6.3 GHz and a relaxation oscillation frequency at around 11.7 GHz. An error-free 10-Gb/s return-to-zero data modulation was demonstrated by using the generated 10-GHz pulse train.