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In this work, SiC nanowire (NW) FETs are prepared and their electrical measurements are presented. From the samples fabricated on the same substrate, various I-Vs shapes are obtained (linear, non linear symmetric, and asymmetric). With the assistance of simulation, we show that this is a result of different values of Schottky Barrier Heights (SBH) at Source (S) / Drain (D) contacts of FETs. An origin for this might be a non uniformity in annealing, NW doping level and high interface traps density (that pins the Fermi level) as well as the high sensitivity of the metal-NW contacts to local surface contaminations.

Quantitative analysis of mixtures of free fatty acids, monoacyl-, diacyl-, and triacylglycerols by a simple and rapid gas chromatography method has been developed. The analysis was carried out on a short capillary column without derivatization. When the triacontane was used as an internal standard, we obtained relative response factors for each lipid class with reproducibility and accuracy. This method could be applied for not only compositional analysis of fats and oils but also monitoring lipase reactions.

Experimental and simulated I-V characteristics of silicon carbide (SiC) nanowire-based field-effect transistors (NWFETs) are presented. SiC NWs were fabricated by using the vapor-liquid-solid mechanism in a chemical vapor deposition system. The diameter of fabricated SiC NWs varied from 60 up to 100 nm while they were some micrometers long. Their I-V characteristics were simulated with SILVACO software, and special attention was paid to explore the role of NW doping level and NW/dielectric interface quality. The fabricated SiC-based NWFETs exhibit a mediocre gating effect and were not switched-off by varying the gate voltage. Based on the simulations, this is a result of the high unintentional doping (estimated at 1times1019 cm-3) and the poor NW/dielectric interface quality. Moreover, a homemade algorithm was used to investigate the ideal properties of SiC-based NWFETs in ballistic transport regime, with NW lengths of 5-15 nm and a constant diameter of 4 nm for which the carrier transport is fully controlled by quantum effects. This algorithm self-consistently solves the Poisson equation with the quantum nonequilibrium Green function formalism. In the ballistic regime, devices with undoped SiC NWs exhibit superior theoretical performances (transconductance: ~43.2times10-6 A/V and ION/IOFF=1.6times105 for a device with 9-nm NW length) based on their simulated characteristics.

Batch and continuous hydrolysis of olive oil in an organic-aqueous two-phase system using the live whole cell of Pseudomonas putida 3SK as a source of a lipase is investigated. The strain was not only fully viable and grown well, but also produced extracellular lipase simultaneously. The degree of hydrolysis, depending on olive oil concentration in the solvents, was maximal at 13.5% (w/v) and decreased with the increase of the substrate concentration. At the optimal condition, a degree of hydrolysis higher than 95% was achieved with 24 h at 30 degrees C when the reaction was carried out in a two-phase batch stirred reactor. For long-term operation a continuous stirred reactor was designed. When the reaction was carried out in a continuous stirred reactor, the degree was hydrolysis reached 86% at a dilution rate of 0.2 h(-1). Satisfactory performance of a two-phase bioreactor was obtained in a long-term continous operation, which lasted for at least 30 days by feeding organic solvent containing olive oil and aqueous media separately. (c) 1994 John Wiley & Sons, Inc.

In view of the current industrial process for the conventional ethanol fermentation, in which raw starch materials are heated at 120 degrees C for 2 h, conditions for an alternative process were set: an overall time from saccharification to ethanol fermentation of within 3-4 days, an operation temperature of below 60 degrees C, an ethanol yield of over 93%, and a ratio of raw material to fermentation volume of within 1:4. To meet these conditions, previously a steeping method of starch materials in 0.5N HCl solution at 60 degrees C for 12 h were used, followed by combined actions of ..cap alpha..-amylase and glucoamylase. The ethanol yield from uncooked cassava starch treated under the conditions described was 95% after fermentation for 3 days with Saccharomyces cerevisiae. However, the use of a relatively higher concentration of acid for steeping is still a problem and gelatinization of starch materials is insufficient. This communication, therefore, describes effects of alkali steeping and structural change of starch granules on the ethanol fermentation. 8 references.