Effects of oxygen on crystallization of amorphous silicon films and polysilicon TFT characteristics

Oxygen ions were implanted into the amorphous silicon film deposited at 540°C in order to study the effects of oxygen on the solid phase crystallization of silicon films. The resulting films were investigated using transmission electron microscopy, x-ray diffraction (XRD), and also by measuring the electrical characteristics of polycrystalline silicon thin film transistors (TFTs) fabricated in the crystallized films. The development of {111} texture as a function of annealing time is similar to films implanted with Si, with higher oxygen samples showing more texture. Transmission electron microscopy shows that the grain size of completely crystallized films varies little with oxygen concentration. The electrical performances of TFTs are found to degrade with increasing oxygen dose. The trap state density increases from 5.6 × 10¹²/cm² to 9.5 × 10¹²/cm² with increasing oxygen dose. It is concluded that for a high performance TFT, oxygen incorporation in the Si film should be kept to 10¹⁹/cm³ or less.     

Alternative Kalman controllability criterion for nonderogatory systems

Kalman's controllability matrix with multiple controls is rearranged to yield a different form of the controllability matrix for nonderogatory systems. The result is proved by expanding the modal forms of the controllability matrices.     

Effects of tomato ketchup and tomato paste extract on hepatic lipid accumulation and adipogenesis

Food Science and Biotechnology - Tomatoes include high levels of lycopene, which is a potent antioxidative, hypolipidemic, and antidiabetic phytochemical. The intake of lycopene is associated with...     

Variation of glucosinolates in vegetable crops of Brassica rapa L. ssp. pekinensis

Glucosinolates of Chinese cabbage (Brassica rapa L. ssp. pekinensis) from Korea were characterised to determine the total glucosinolate content and the diversity amongst glucosinolates; 24 varieties were analysed. The profiles of 14 glucosinolates identified from the leaves were subjected to principal component analysis (PCA) to evaluate the differences among varieties. The Kori, Sandun and e-Norang varieties separated from the others based on glucosinolate concentration. Genetically modified Chinese cabbage containing the bar gene could not be separated from non-genetically modified varieties. Glucobrassicanapin, 4-methoxyglucobrassicin, gluconapin and glucobrassicin in Chinese cabbage were confirmed as the main glucosinolate compounds. The Kori, Sandun and e-Norang varieties appear to be good candidates for future breeding programmes since they have a high glucosinolate content. The presence of indolic glucosinolates in all varieties should be studied more extensively because they are the precursor of indole-3-carbinol, a potent cancer chemopreventive agent.     

Application of triacylglycerol and fatty acid analyses to discriminate blended sesame oil with soybean oil

Triacylglycerols (TAGs) and fatty acids in the mixture of sesame oil (SO) with soybean oil were analysed using high performance liquid chromatography (HPLC)–an evaporative light scattering detector (ELSD) and gas chromatography (GC)–a flame ionisation detector (FID). Relative percentage of linolenic acid increased rapidly compared to those of oleic and linoleic acids as the ratio of soybean oil increased in the blended SO. Peak responses of trilinolein (LLL) and trilinolenin (LnLnLn) by HPLC–ELSD was higher than those by GC–FID from the same concentration of TAGs. The presence of LLLn peak, the contents of linolenic acid, and the relative ratio of L/S, O/Ln, and L/Ln from fatty acids or LLL/OOO from TAGs could be useful indicators to detect the blended SO with soybean oil. TAG analysis by HPLC–ELSD coupled with fatty acids by GC–FID can be useful methods to discriminate blended SO with soybean oil.     

Performance of β-galactosidase pretreated with lactose to prevent activity loss during the enzyme immobilisation process

In this study, Kluyveromyces lactis β-galactosidase was pretreated with lactose to prevent loss of activity during the immobilisation process, and glutaraldehyde was used as a linker to immobilise β-galactosidase on the surface of a silica gel. The pretreatment of β-galactosidase strongly improved its activity after immobilisation. Specifically, the activity of pretreated immobilised β-galactosidase was 2.6 times greater than that of non-pretreated immobilised β-galactosidase. The optimal temperature, pH and ionic strength of buffer for pretreated immobilised β-galactosidase were 37 °C, pH 7.5 and 20 mM potassium phosphate buffer, respectively. These values were shifted by 5 °C and pH by 0.5 when compared to the soluble β-galactosidase. Moreover, the pretreated immobilised β-galactosidase showed a better reusability than did non-pretreated immobilised β-galactosidase, with 63.9% of its original activity being retained after 10 reuses.     

Radiation‐Modified Carboxymethyl Starch Derivative as Metal Scavenger in Aqueous Solutions

Corn starch was chemically modified using sodium chloroacetate to yield carboxymethyl starch (CMS). The aqueous solutions of CMS at 15 and 50% (w/w) concentration were then irradiated by electron beam (EB) at various dosages (1, 2, 3, 5, 10, 20, and 50 kGy), resulting in a cross‐linked carboxymethyl starch (CCMS). The maximum gel fraction, i.e. the highest degree of cross‐linking, was achieved with a 50% (w/w) aqueous CMS solution irradiated at 2 kGy EB dosage. Metal removal efficiency of the CCMS was then evaluated for the extraction of copper (Cu) and cadmium (Cd) ions from aqueous solutions. Our results showed that the metal adsorption is pH dependent and the adsorption increases with increase of the pH of the metal solution from acidic towards neutral. The adsorption efficiency also showed the maximum value at the highest gel content, demonstrating the enhancement of adsorption by the physical entrapment of the ions in the CCMS network in addition to the primary chemical adsorption.     

Cross-section segmentation for improving the shape accuracy of microstructure array in projection microstereolithography

Microstereolithography is a microfabrication technology done in a layer-by-layer fashion. It is useful to fabricate a microstructure with both a high aspect ratio and a complex shape. Projection microstereolithography is suitable for microstructure array fabrication due to the fast process time using patterned light irradiation. However, nonuniform light intensity on the resin surface deteriorates the fabrication precision. This research proposes the cross-section segmentation for uniform exposure energy on the resin surface. Each subsection consisting of a cross-section is separately converted into an image file. The estimated exposure time of each subsection is stored in a text file and used during the fabrication. Finally, several microstructure arrays are fabricated to verify this method.