Segmented block copolyetheramides based on nylon 6 and polyoxypropylene. I. Synthesis and characterization

Various segmented block copolyetheramides based on nylon 6 and polyoxypropylene (POP) were synthesized by melt polymerization of caprolactam (CPL) and polyoxypropylene diamines (POPD) as a function of the size and content of POPD. As the content of POPD in the feed increased, the IR absorption band at 1110 cm^?1 increased. The ¹H-NMR analysis indicated that peaks characteristic of methylene groups in POP unit appeared at 1.2, 3.6, and 3.8 ppm. The compositions of the hard and soft segments in the block copolymer were determined from the NMR data. The POP content in copolymer was higher than that in the feed due to the removal of unreacted CPL by water extraction. The average block lengths of the hard and soft segments were calculated from molecular weights and copolymer compositions. © 1994 John Wiley & Sons, Inc.     

Crystallization and properties of a perovskite glass-ceramic

Crystallization and properties of a PbO-BaO-TiO₂-Al₂O₃-SiO₂-B₂O₃ glass-ceramic were studied. The primary crystalline phase was bulk-crystallized perovskite titanate. The secondary crystalline phases were a bulk-crystallized transient PbTi₃O₇ phase and a surface-crystallized PbO · Al₂O₃ · 2SiO₂ phase. As the heating temperature/time increased, the structure of the precipitated perovskite crystals was transformed from cubic to tetragonal, and the measured c/a ratio increased to approach a constant value which is lower than that for the strain-free crystal. Moreover, the crystallized amount of perovskite phase first increased to a maximum, then decreased. The results have been explained by a coarsening process of the perovskite particles. With increasing frequency (200-10⁵ Hz), the dielectric constant of the crystallized samples ranged from about 80-70. The dielectric constant was mainly determined by the perovskite content.     

Enhanced write performance of a 64-mb phase-change random access memory

The write performance of the 1.8-V 64-Mb phase-change random access memory (PRAM) has been improved, which was developed based on 0.12-/spl mu/m CMOS technology. For the improvement of RESET and SET distributions, a cell current regulator scheme and multiple step-down pulse generator were employed, respectively. The read access time and SET write time are 68 ns and 180 ns, respectively.     

Multilinguistic handwritten character recognition by Bayesiandecision-based neural networks

In this paper, we present a Bayesian decision-based neural network (BDNN) for multilinguistic handwritten character recognition. The proposed self-growing probabilistic decision-based neural network (SPDNN) adopts a hierarchical network structure with nonlinear basis functions and a competitive credit-assignment scheme. Our prototype system demonstrates a successful utilization of SPDNN to the handwriting of Chinese and alphanumeric character recognition on both public databases (CCL/HCCR1 for Chinese and CEDAR for the alphanumerics) and in-house database (NCTU/NNL). Regarding the performance, experiments on three different databases all demonstrated high recognition (86-94%) accuracy as well as low rejection/acceptance (6.7%) rates. As for the processing speed, the whole recognition process (including image preprocessing, feature extraction, and recognition) consumes approximately 0.27 s/character on a Pentium-100 based personal computer, without using a hardware accelerator or coprocessor     

Hybrid approach in prototyping functional medical safety devices: A case study

Utilisation of functional prototypes during the upstream design stage is able to shorten the product development cycle of a medical device and quicken the transfer process to mass manufacturing. Innovative synergy of conventional manufacturing techniques and rapid prototyping techniques is thus needed to fabricate functional prototypes successfully. This case study reports on the development of an automatically activated safety needle using different prototyping approaches for the fabrication of functional prototypes. The approaches include rapid prototyping, computer numerical control (CNC) machining and vacuum casting. The challenges of each technique are discussed and solutions are presented. A hybrid technique involving CNC machining and vacuum casting is adopted to fabricate the prototypes. This hybrid prototyping approach was able to expand the choices for materials to fabricate the prototypes and thus enabling the validation of the design mechanism in a shorter time.     

Modeling and simulation of motor/turbine processes in utility plant

To achieve safe operation and to improve economics it is imperative to monitor and analyze demand and supply of utilities and to meet utility needs in time. The main objective of motor/turbine processes is to manipulate optimal balances on steam and electricity in utility plants. The optimal operation of motor/turbine processes is by far the most important to improve economics in the utility plant. In order to analyze motor/turbine processes, steady state models for steam generation equipment and steam distribution devices as well as turbine generators are developed and analyzed in this work. In addition, heuristics concerning various operational situations are incorporated in the models. The motor/turbine optimal operation system is based on utility models and operational knowledgebase, and provides optimal operating conditions when the amount of steam demand from various steam headers is changed frequently. The optimal operation system also produces optimal selection of driving devices for utility pumps to reduce operating cost.     

Octylphenol ethoxylate surfactant as a suppressor in copper electrodeposition

In this study, the role of octylphenol ethoxylate (Triton X-100) surfactant as a suppressor in Cu electrodeposition has been examined. The inhibition ability of Triton X-100 was qualitatively and quantitatively evaluated with cyclic voltammograms and Koutecký–Levich plots, and compared with that of polyethylene glycol (PEG) with similar molecular size. The presence of a hydrophobic benzene-ring in its structure made it inhibit Cu deposition more strongly than PEG. The inhibition function of Triton X-100 depended on the substrate material and it was influenced by the presence of Cl^? and bis sulphopropyl disulphide in the electrolyte indicating that the characteristics of Triton X-100 were similar to those of PEG, which was also demonstrated by gap filling of Cu with using Triton X-100 in the replacement of PEG. The effect of Triton X-100 on the properties of the deposit film was also investigated, and it was found that it suppressed the three-dimensional growth of Cu.     

Experimental study of effects of wicks and boundary conditions on thermal performance of heat pipes

The inherent two-phase heat transport of heat pipes (HPs) is progressively being examined for potential uses. These thermal devices are affected by many operating factors, prompting this study to investigate the effects of different types of wicks and working conditions on the time-dependent thermal behavior. Primarily, the effects of different wick performances were investigated under various operating conditions. The resulting surface temperatures depicted in the time to steady performance and the dry-out behavior revealed the conditions to improve the HPs design. The thermal resistance decreased from 0.6 K/W (at 25 W) to 0.05 K/W (at 200 W) by increasing the HP diameter from 6 to 10 mm; these values are relative to those of copper rods, which decrease from 2.70 K/W (at 25 W) to 0.40 K/W (at 200 W). Non-linear and linear temperature responses were recorded when the HPs diameter and length were varied. Compared to conventional mesh and groove wicks, the composite groove-sintered, mesh-sintered, and groove-mesh wicks recorded lower thermal resistance with distinctively faster startup times, lower startup temperatures, better temperature uniformity and less dynamic instability. Tilting the HPs relative to the horizontal position lessens failure tendencies. Usually, dynamic responses are typically first-order under the conditions studied. Hence, proper sizing of HPs and correct wick selection can improve their performance.

     

Perilla Oil Reduces Fatty Streak Formation at Aortic Sinus via Attenuation of Plasma Lipids and Regulation of Nitric Oxide Synthase in ApoE KO Mice

Consumption of n‐3 polyunsaturated fatty acids (PUFA) is associated with a reduced incidence of atherosclerosis. Perilla oil (PO) is a vegetable oil rich in α‐linolenic acid (ALA), an n‐3 PUFA. In this study, antiatherogenic effects and related mechanisms of PO were investigated in atherosclerotic mice. Apolipoprotein E knockout (ApoE KO) mice (male, n = 27) were fed high‐cholesterol and high‐fat diets containing 10 % w/w lard (LD), PO, or sunflower oil (SO) for 10 weeks. Plasma triglyceride, total cholesterol, and low‐density lipoprotein cholesterol concentrations reduced in the PO and SO groups compared to the concentrations in the LD group (P < 0.05). The PO group showed reduced fatty streak lesion size at the aortic sinus (P < 0.05) compared to the sizes in the LD and SO groups. A morphometric analysis showed enhancement of endothelial nitric oxide synthase expression and reduction of inducible nitric oxide synthase expression in the PO group compared to that in the LD group (P < 0.05). Furthermore, aortic protein expression of intercellular cell adhesion molecule 1 and vascular cell adhesion molecule 1 was diminished in the PO group compared to that in the LD and SO groups (P < 0.05). These findings suggested that PO inhibited the development of aortic atherosclerosis by improving the plasma lipid profile, regulating nitric oxide synthase, and suppressing the vascular inflammatory response in the aorta of ApoE KO mice.     

Development of low calorie roasted radish tea beverage with anti-oxidant activity

A functional radish tea beverage was developed using pressure roasted radish pieces, barley, and cassia seeds. Stevia, short-chain fructooligosaccharides (scFOS), and inverted sugar syrup were used as sugar substitutes. The formula developed for mass production was, pressure roasted radish pieces, barley, and cassia seed teas prepared separately, then mixed (3:1:1, v/v/v). Inverted sugar syrup (54.4 g/L), stevia (0.73 g/L), scFOS (17 g/L), citric acid (0.01%), and vitamin C (0.05%) were added. Sweetness and caloric contents of the roasted radish tea beverage were 6.5°Bx and 19.35 Kcal/100 mL, respectively. Based on consumer acceptance testing (n=60 persons), overall acceptance, taste, and sweetness scores of the roasted radish tea beverage were higher than for a commercially available H tea beverage. Caloric contents were reduced by approximately 23.5% using sugar substitutes. The IC₅₀ value for the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of hot water extracts of dried radish increased 2.5-fold after pressure roasting.