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941.
Yu‐Kang Lo Jing‐Yuan Lin Chung‐Yi Lin Shih‐Jen Cheng Huang‐Jen Chiu 《International Journal of Circuit Theory and Applications》2013,41(4):410-423
A novel power factor corrector (PFC) composed of two‐phase discontinuous conduction mode (DCM) boost PFCs and a coupled inductor is proposed in this paper. By coupling the two‐phase boost inductors into the same magnetic core, both the circuit volume and the input ripple current are reduced. Therefore, the power factor (PF) value and the power density are improved. In addition, the output capacitor size can be smaller. The proposed topology distributes the input current and output current equally for the two phase modules. A cut‐in‐half duty cycle can decrease the conduction losses of the switches, and both the turns and diameters of the inductor windings, which help more in the reduction of the circuit volume. The advantages of a DCM boost PFC, such as natural zero‐current‐switching (ZCS) of the output diode, a natural PFC function and the simplified EMI filter design, are maintained. Detailed analysis and design of the proposed topology and the experimental results on a prototype with a 380‐V output voltage and a 200‐W output power are provided. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
942.
943.
Hsien-Tang Chiu Chi-Yung Chang Hsin-Wei Pan Tzong-Yiing Chiang Ming-Tai Kuo Yu-Hsiang Wang 《Journal of Polymer Research》2012,19(2):9791-12
In this study the use of polyurethane foam (PUF) as a heat seal coating for potential application in medical pouch packaging
were investigated. We prepared PUF coatings at various foam densities and cell densities through mechanical foaming at various
stirring speeds; then used a LUMisizer to examine their stabilities. After applying PUF coatings of various foam densities
onto a medical packaging material (Tyvek?) at various thicknesses, then employed impulse heat sealing with linear low density
polyethylene (LLDPE) films to fabricate medical pouches. In addition to investigating the morphology, tack properties, adhesion,
scratch resistance, flexibility, and durability of the PUF coats, the peel strength and air permeability of the medical pouches
were also measured. Increasing the foam density of the PUF coatings increased their stability; the PUF coats prepared at a
higher foam density exhibited greater tackiness (<1 g/cm2), adhesion (5B), scratch resistance (HB), flexibility (passes), and durability (ΔYI ≤ 5). The peel strength measured in the T-peel configuration increased upon increasing the foam density and decreasing the
coating thickness of the PUF coat/LLDPE pouches. The air permeability of the pouches increased upon increasing the foam density
and cell density of the PUF coat/LLDPE pouches. Morphological studies using scanning electron microscopy were consistent with
the experimental results. 相似文献
944.
Dev-Aur Chou Yueh-Hsiung Kuo Ming-Shiou JanYuan-Yen Chang Yi-Chen ChenHis-Lin Chiu Wei-Tang ChangChin-Lin Hsu 《Food chemistry》2012,131(4):1460-1465
The objective of this study was to investigate the anticancer activity of caffeate derivatives in human cancer cells. Our results demonstrate that caffeate derivatives decreased the population growth of COLO 205, assessed using the MTT assay. However, caffeate derivatives, at the concentrations used in this study (0-250 μM) did not affect the viability of HepG2, Huh7, PLC5, and SK-Hep-1 cells. Flow cytometric analysis of COLO 205 cells exposed to decyl caffeate showed that the number of apoptotic cells increased in a time- and dose-dependent manner. Western blot analysis revealed that decyl caffeate stimulated an increase in protein expression levels of p53, Fas, FasL, AIF, and Apaf-1. Additionally, treatment with decyl caffeate changed the expression levels of Bcl-2 family members and subsequently induced the activation of caspase-12, caspase-9, and caspase-3, which was followed by cleavage of PARP. Our findings highlight the chemopreventive potential of decyl caffeate. 相似文献
945.
In this study, individual selected lactic acid bacteria strains Lactobacillus acidophilus (LA), L. delbrueckii subsp. lactis (LDL), and L. gasseri (LGA) were grown in Chingshey purple sweet potato (CPSP) substrate/media. CPSP is rich in anthocyanin, which possesses antioxidant activity and in vitro cell assay. The antioxidant ability and functional properties of the fermented milk were examined. High-performance liquid chromatographic (HPLC) method was used to analyze the free amino acid, organic acids, and anthocyanin content. Total phenolic compounds, scavenging effects of 1,1-diphenyl-2-picyl-hydrazyl (DPPH) radicals, and scavenging effects of superoxide anion radicals were determined to evaluate the antioxidant ability of the samples. The cell proliferation of the fermented PSP milk was evaluated by 3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl Tetrazolium Bromide (MTT) assay. The result indicated that the antioxidant ability of the fermented CPSP milk through LA, LDL, and LGA strains was significantly higher than CPSP. The main anthocyanins present in the samples are cyanidin and delphinidin. MTT assay has revealed that incubation with both PSP and fermented CPSP milk prevented the cell death of macrophage-like RAW264.7 cells. The potential health benefit of fermented PSP milk through LA, LDL, and LGA strains makes the further application of CPSP in health food highly worthwhile. PRACTICAL APPLICATION: (1) In our study, we have employed the γ-aminobutyric acid (GABA), organic acid contents, total phenol content, anthocyanins content, DPPH, oxygen radical absorbance capacity, superoxide dismutase activity assay, and cytotoxicity assay to assess the functional properties of fermented CPSP milk by different lactic acid bacteria. (2) Our results have revealed that the fermented CPSP milk samples possess high GABA concentrations, organic acid contents, anthocyanins contents, and antioxidant activity. This will provide potential opportunity to develop different functional food products from fermented CPSP milk. (3) The potential health benefit of fermented CPSP milk makes the further application of CPSP in health food highly worthwhile. 相似文献
946.
Carotenoids, lutein, zeaxanthin, and β-carotene, common in many vegetables, have been shown to be important in visual health-promoting. However, cooking practice has a great impact on these bioactive compounds. The objective of this work was to evaluate the effect of three common Chinese domestic cooking methods including boiling, stir-frying, and deep-frying on the composition of lutein, zeaxanthin, β-carotene and their trans/cis (E/Z) isomers of vegetables. Among the 25 fresh vegetables commonly consumed in Taiwan, it was found that cilantro, Thai basil leaves, sweet potato leaves, and choy sum contained the 1st–4th highest amount of total carotenoids content (TCC), respectively. Boiling preserved the majority of carotenoids, whereas stir-frying and deep-frying significantly decreased TCC and (all-E)-forms of carotenoids. In addition, (all-E) – and (13Z)-/(13′Z)-carotenoids exhibited similar trends during boiling, since the boiling time required to reach maximum concentration for (all-E)-carotenoids was almost the same as that for (13Z) – plus (13′Z)-isomers. An overall increase of (9Z)/(9′Z)-carotenoid isomers was observed in all boiled vegetables, probably because of E/Z isomerization, which could partially result in the formation of more bioactive compounds such as (9Z)-β-carotene. Boiling may be the preferred practice of domestic cooking methods to preserve carotenoids in vegetables. 相似文献
947.
Yu‐Kang Lo Ching‐Hui Yu Tian‐Fu Pan Huang‐Jen Chiu 《International Journal of Circuit Theory and Applications》2012,40(6):595-606
A new shunt current shaping scheme for multiple paralleled dc–dc converters is proposed in this paper. The current command for the shunt current shaper is indirectly obtained by forcing the source current to follow the demanded sinusoidal signal. The amplitude of the demanded sinusoidal source current that is in‐phase with the source voltage can be determined from the sensed load currents of the post‐stage dc–dc converters. Neither high‐order filters nor time‐consuming computations are required. The shunt current shaper supplies all the harmonics and the out‐of‐phase fundamental of the distorted input current and the power source only supplies the in‐phase fundamental component. Experimental results on a prototype system verify the feasibility of the presented scheme. The implemented shunt current shaper demonstrates an efficiency of 92% and a nearly unity power factor at the utility side. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
948.
Providing an efficient and stable communication framework of Vehicular Ad hoc Network (VANET) is an emerging issue. Most of conventional VANET communication schemes only support short range transmission, vehicles need to relay traffic data or frequently switch to different roadside units. Such an ad hoc-based method suffers a high jitter delay and makes it difficult to develop travel and real-time multimedia services, such as traffic information dissemination and fleet management. Fortunately, existing novel wireless technologies, e.g. WiMAX mobile multi-relay (MMR), provide long transmission range and high transmission rate in mobile environments. This study presents a Safety/Vehicular Information Delivery (SVID) framework, an application-layer VANET communication protocol. A power-abundant, large size vehicle, called SIP-based relay vehicle (SRV), e.g. long distance transportation bus, plays as a relay station (RS) providing the connectivity to other small vehicles around it. To provide VANET services in SVID, this work adopts a SIP-based mechanism. The proposed scheme can provide more efficient communication than conventional VANET ad hoc mode. Simulation results show that the proposed scheme achieves a low SIP transaction time, jitter delay, frame loss rate while avoiding the broadcast storm problem. 相似文献
949.
Yung-Hsiang Chiu Kuo-Liang Chung Wei-Ning Yang Chien-Hsiung Lin Yong-Huai Huang 《Journal of Visual Communication and Image Representation》2013,24(7):867-884
Compressing mosaic video sequences is necessary for storage and transmission over the internet. However, mosaic video sequences with different red–green–blue (RGB) color filter arrays (CFAs) require different compression schemes. We propose a two-stage universal intra coding scheme for compressing mosaic video sequences with arbitrary RGB-CFAs in high efficiency video coding (HEVC). Based on the associated mosaic structure, the proposed scheme first demosaics the neighboring reference pixels and then predicts the color value of the target pixel using the color values of the identical color components in the demosaiced reference pixels. Experimental results demonstrate that the proposed universal intra coding scheme achieves substantial improvement on bitrate while preserving the quality of the reconstructed video sequences. 相似文献
950.
Nitrogen/titanium dioxide (N/TiO2) visible light photocatalysts were prepared using the sol–gel method. The catalysts were characterized using transmission electron microscopy, reflective UV–visible spectroscopy, specific surface area measurements, and X-ray diffraction. The prepared catalysts were used to generate hydrogen gas through the water-splitting reaction under visible light (wavelengths greater than 400 nm). Various N/Ti addition ratios were tested, and the hydrogen generation rates were compared to determine the optimal ratio. The maximal hydrogen production rate (approximately 55 μmol h−1 g−1) was attained when the N/Ti ratio of N–TiO2 was 10. When PdO and Pt were loaded onto the N–TiO2 catalyst, the hydrogen generation rates increased to 544 and 772 μmol h−1 g−1, respectively. The highest hydrogen production rate (2460 μmol h−1 g−1) was obtained when bimetallic 0.05 wt% PdO-0.10 wt% Pt/N–TiO2 was used. After three times use the hydrogen yield of the catalyst was maintained as 83%. A possible mechanism of water splitting catalyzed by this visible light photocatalyst is proposed. 相似文献