Preparation and epoxy curing of novel dicyclopentadiene‐derived Mannich amines

Phenol/dicyclopentadiene (DCPD) adducts were prepared from the BF₃‐catalyzed reaction of p‐nonylphenol and dicyclopentadiene at molar ratios of 2 : 1 and 3 : 2. The phenol‐terminating adducts were consequently reacted with diethylenetriamine and formaldehyde using Mannich reaction conditions. These products containing phenol, amine and tricyclodecane functionalities in the same molecule can be used as epoxy curing agents. The diethylenetriamine was add to the phenol via Mannich reaction at approximately 50% theoretical equivalent. The multiple N H groups in amines and the O H groups in phenols provide crosslinking sites for epoxy resins. The cured epoxy resins show improvement in tensile strength and elongation in comparison with those cured by the poly(oxypropylene) diamine (400 molecular weight) or diethylenetriamine. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2129–2139, 1999     

Interfacial reactions of cobalt thin films on (001) GaAs

Interfacial reactions between cobalt thin films and (001) GaAs have been studied by transmission electron microscopy, energy-dispersive analysis of x-rays in a scanningTEM, Auger electron spectroscopy and x-ray photoelectron spectroscopy. The completely reacted layer was found to be “β-Ga₂0₃/(CoGa, CoAs)/GaAs.” The formation of a surface layer ofβ-Ga₂O₃ and the use of encapsulated samples minimized As loss from the reacted layer. Both CoGa and CoAs were found to grow epitaxially on (001) GaAs. The orientation relationships between CoGa and GaAs were determined to be [001] CoGa//[001] GaAs and (220) CoGa//(220) GaAs. The Burgers vectors of interfacial dislocations were identified as 1/2 〈101〉 and 1/2 〈011〉 which are inclined to the (001) GaAs surface. Almost all of the CoGa films were found to be epitaxially related to the surface. No interfacial dislocations were observed in most of the epitaxial CoAs films which are considered to be pseudomorphic with respect to GaAs. The orientation relationships between CoAs and GaAs were determined to be [101] CoAs//[011] GaAs and (020) CoAs//(220) GaAs. Two-step annealing was found to be effective in promoting epitaxial growth.     

Focused ion beam-fabricated Au micro/nanostructures used as a surface enhanced Raman scattering-active substrate for trace detection of molecules and influenza virus

The focused ion beam (FIB) technique was used to precisely fabricate patterned Au micro/nanostructures (fibAu). The effects of surface enhanced Raman scattering (SERS) on the fibAu samples were investigated by adjusting the geometrical, dimensional, and spacing factors. The SERS mechanism was evaluated using low-concentration rhodamine 6G (R6G) molecules, physically adsorbed or suspended on/within the micro/nanostructures. The results indicated that for detecting R6G molecules, hexagon-like micro/nanostructures induced a higher electromagnetic mechanism (EM) due to the availability of multiple edges and small curvature. By decreasing the dimensions from 300 to 150 nm, the laser-focused area contained an increasing number of micro/nanostructures and therefore intensified the excitation of SERS signals. Moreover, with an optimized geometry and dimensions of the micro/nanostructures, the relative intensity/surface area value reached a maximum as the spacing was 22 nm. An exponential decrease was found as the spacing was increased, which most probably resulted from the loss of EM. The spacing between the micro/nanostructures upon the fibAu was consequently regarded as the dominant factor for the detection of R6G molecules. By taking an optimized fibAu to detect low-concentration influenza virus, the amino acids from the outermost surface of the virus can be well distinguished through the SERS mechanism.     

An effective and efficient compression algorithm for ECG signals with irregular periods

This paper presents an effective and efficient preprocessing algorithm for two-dimensional (2-D) electrocardiogram (ECG) compression to better compress irregular ECG signals by exploiting their inter- and intra-beat correlations. To better reveal the correlation structure, we first convert the ECG signal into a proper 2-D representation, or image. This involves a few steps including QRS detection and alignment, period sorting, and length equalization. The resulting 2-D ECG representation is then ready to be compressed by an appropriate image compression algorithm. We choose the state-of-the-art JPEG2000 for its high efficiency and flexibility. In this way, the proposed algorithm is shown to outperform some existing arts in the literature by simultaneously achieving high compression ratio (CR), low percent root mean squared difference (PRD), low maximum error (MaxErr), and low standard derivation of errors (StdErr). In particular, because the proposed period sorting method rearranges the detected heartbeats into a smoother image that is easier to compress, this algorithm is insensitive to irregular ECG periods. Thus either the irregular ECG signals or the QRS false-detection cases can be better compressed. This is a significant improvement over existing 2-D ECG compression methods. Moreover, this algorithm is not tied exclusively to JPEG2000. It can also be combined with other 2-D preprocessing methods or appropriate codecs to enhance the compression performance in irregular ECG cases.     

Microemulsion polymerization of microlatex in sublimation ink for cotton fabric ink jet printing

A novel microlatex of styrene/2‐ethylhexylacrylate (2‐EHA)/2‐hydroxyethyl methacrylate (2‐HEMA)/N‐(isobutoxy methyl) acrylamide (IBMA) copolymer was synthesized and mixed in sublimation inks to be inkjet printed on the cotton fabric to provide soft hand feel and good color fastness after heat‐press. In the optimized microemulsion composition with highest monomer mixture amount, polymerizable maleate surfactants with moderate EO value attained smaller microemulsion droplet size in mono distribution and lower dosage than conventional POE surfactants in combination with anionic surfactants. With adopted semicontinuous process in microemulsion copolymerization at 65°C, the polymerizable surfactants stabilized the growth of microlatex particle size within 70 nm in 240 min and attained 100% of monomer conversion rate with two initiator systems, 2‐2‐azobis(2‐methlypropionamidine dihydrochloride (AAPH) and tert‐butylhydroperoxide (TBHP)/sodium formaldehyde sulfoxylate (SFS). The microlatex particle size of two surfactant systems increased with higher conversion rate and reaction temperature, which synchronized with initiator concentration. High polymer solid content was contributed mainly by IBMA monomer ratio requiring higher amounts of anionic surfactants and 2‐HEMA as a cosurfactant in particle stabilization. Although the optimum ink containing high IBMA microemulsion exhibited small variation in viscosity, pH value and surface tension, disperse dyes in four colors had different interaction with the microlatex to demonstrate distinct printing durability and color performance. The resulted cotton fabric attained high K/S value for color strength, great AATCC grade for color fastness, and nearly zero color difference for negative dye particle diffusion or migration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of rice bran on sensory and physico-chemical properties of emulsified pork meatballs

Four kinds of bran, which are milled from important rice cultivators in Taiwan, have high contents of dietary fiber, fat and protein. The use of rice bran in Kung-wan, an emulsified pork meatball, was investigated. It was found that protein and fat contents, and white index of meatballs decreased as the amount of bran increased. A texture profile analysis (TPA) also indicated the hardness, gumminess and chewiness of the Kung-wan decreased. The sensory scores of taste, texture and overall acceptability of meatballs with less than 10% added bran showed no significant difference from those for meatballs without bran. However, the added amount of 15% enriched meatballs resulted in inferior sensory scores. The bran’s particle size profoundly affected the sensory and physico-chemical properties of the meat products. Meatballs enriched with smaller bran particles possessed higher TPA indices and sensory scores than those added with larger ones. No significant differences in proximate composition, cooking yield, color and sensory quality were found among emulsified meatballs enriched with four different kinds of bran. Conclusively, the suitable amount of rice bran that should be added to emulsified pork meatballs was less than 10% and a smaller particle size would result in better quality.     

A Unified Framework of the Cloud Computing Service Model

After a comprehensive literature review and analysis, a unified cloud computing framework is proposed, which comprises MapReduce, a vertual machine, Hadoop distributed file system (HDFS), Hbase, Hadoop, and virtualization. This study also compares Microsoft, Trend Micro, and the proposed unified cloud computing architecture to show that the proposed unified framework of the cloud computing service model is comprehensive and appropriate for the current complexities of businesses. The findings of this study can contribute to the knowledge for academics and practitioners to understand, assess, and analyze a cloud computing service application.     

Characterization of polysilicon oxides thermally grown anddeposited on the polished polysilicon films

This work examines the characteristics of polyoxides thermally grown and deposited on polished polysilicon films. A well-controlled chemical mechanical polishing (CMP) process is also presented to achieve a planar surface morphology for polysilicon films. The thermally-grown and deposited polyoxides on the polished polysilicon films exhibit a lower leakage current, higher dielectric breakdown field, higher electron barrier height, lower electron trapping rate, lower density of trapped charges, and markedly higher charge to breakdown (Q_bd) than the conventional polyoxide. In particular, the deposited polyoxide on the polished polysilicon film has the highest dielectric breakdown field, lowest electron trapping rate, and highest charge to breakdown due to the planar polyoxide/polysilicon interface. In addition, experimental results indicate that the trapped charges of the polished samples are located in the polyoxides' upper portion, which differs from conventional polyoxides. Undoubtedly, the deposited polyoxide on the polished polysilicon film considered herein is the most promising candidate to yield optimum characteristics of polyoxide