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91.
92.
Jian‐Min Wang Sen‐Tung Wu Shang‐Chin Yen Jing‐Yuan Lin 《International Journal of Circuit Theory and Applications》2015,43(12):1879-1898
This study proposes a simple control scheme for using single‐stage flyback (SSF) converters in lighting source applications for LEDs. Among the advantages of the average current mode is an I/O current ripple that is only one‐half of the critical conduction mode (CRM). This condition helps extend the output capacitor lifetime while lowering the input EMI capacitance input EMI capacitance. The SSF converter proposed in this study operates in continuous conduction mode (CCM). In addition, two sample‐and‐hold (S/H) circuits are placed at the output voltage loop and feed‐forward path, respectively. Since these S/H circuits access the average output current and average feed‐forward voltage, the LED driver is unaffected by the 120‐Hz ripple noise, the total harmonic distortion (THD) is reduced, and the transient response of the output current is improved. Finally, the operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also designed and tested to verify the feasibility. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
93.
Ching‐Cheng Chen Yen‐Pei Fu Shao‐Hua Hu 《Journal of the American Ceramic Society》2015,98(9):2803-2811
The TiO2/SiO2/Ni–Cu–Zn ferrite composite for magnetic photocatalysts with high photocatalytic activity is successfully prepared in this study. The composite are composed of spherical or elliptical Ni–Cu–Zn ferrite nanoparticles about 20–60 nm as magnetic cores, silica as barrier layers with thickness of 15 nm between the magnetic cores and titania shells with thickness approximately 1.5 nm. Photodegradation examination of TiO2/SiO2/ Ni–Cu–Zn ferrite composite was carried out in methylene blue (MB) solutions illuminated under a Xe arc lamp with 35 W and color temperature of 6000 K. The results indicated that about 47.1% of MB molecules adsorbed on the TiO2/SiO2/Ni–Cu–Zn ferrite composite within 30 min mixing due to it higher pore volume of 0.034 cm3/g, and after 6 h Xe lamp irradiation, 83.9% of MB 16.1% was photodegraded. Compared with the TiO2 /Ni–Cu–Zn ferrite composite, the TiO2/SiO2/Ni–Cu–Zn ferrite composite with silica barrier layer prohibited the photodissolution and enhanced the photocatalytic ability. The magnetic photocatalyst shows high photocatalytic efficiency that the apparent first‐order rate constant kobs is 0.18427 h?1, and good magnetic property that the saturation magnetization (Ms) of is 37.45 emu/g, suggesting the magnetic photocatalyst can be easily recovered by the application of an external magnetic field. 相似文献
94.
Preparation and characterization of methoxy‐poly(ethylene glycol) side chain grafted onto chitosan as a wound dressing film 下载免费PDF全文
Cheng‐Han Yang Szu‐Hsien Chen Yun‐Wen Pan Ching‐Nan Chuang Wen‐Chi Chao Tai‐Horng Young Wen‐Yen Chiu Chih‐Kuang Wang Kuo‐Huang Hsieh 《应用聚合物科学杂志》2015,132(31)
Chitosan has received extensive attention as a biomedical material; however, the poor solubility of chitosan is the major limiting factor in its utilization. In this study, chitosan‐based biomaterials with improved aqueous solubility were synthesized. Two molecular weights (750 Da and 2000 Da) of methoxypoly(ethylene glycol) (mPEG) were grafted onto chitosan (mPEG‐g‐chitosan) to form a ~100‐μm‐thick plastic film as a wound dressing. The chemical structures of the mPEG‐g‐chitosan copolymers were confirmed using Fourier transform infrared spectroscopy (FTIR), and the thermal properties were characterized using thermogravimetry analysis (TGA). Their microstructures were observed using scanning electron microscopy (SEM). The other properties were analyzed via the swelling ratio, tensile strength, elongation, and water vapor transmission rate (WVTR). Biocompatibility evaluations through biodegradability, cytotoxicity, and antimicrobial effect studies were also performed. The obtained mPEG‐g‐chitosan copolymers were soluble in slightly acidic aqueous solutions (pH~6.5) at a concentration of 10 wt %. The optimal mPEG‐g‐chitosan hydrogels had swelling ratios greater than 100% and WVTRs greater than 2000 g/m2/day. Their performance against Staphylococcus aureus will be subjected to further improvements with respect to medical applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42340. 相似文献
95.
Self‐Crack‐Filled Graphene Films by Metallic Nanoparticles for High‐Performance Graphene Heterojunction Solar Cells 下载免费PDF全文
96.
Planar Heterojunction Perovskite Solar Cells Incorporating Metal–Organic Framework Nanocrystals 下载免费PDF全文
97.
Kuo-chung Chang Hung-Wei Yen Chih-Ching Chiang Neeraj Parolia 《International Journal of Project Management》2013
The extent of knowledge contribution is the key to the success of system development projects. Knowledge contribution refers to the knowledge that is provided to increase a team's efficiency and achieve its goal. This study proposes a research model exploring factors that influence the extent of knowledge contribution from a social cognitive perspective. These factors include the team relationship commitment, team relationship norms, and awareness of expertise location. Additionally, this study argues that a team's awareness of expertise location mediates the effects of affective commitment and relationship norms on knowledge contribution. The result shows that the awareness of expertise location plays a crucial mediating role in the relationships between the two socially prescribed motivations and knowledge contribution. Moreover, team relationship commitment has an important impact on team established relational norms. 相似文献
98.
Hsing Yuan Yen 《臭氧:科学与工程》2016,38(2):163-171
This study evaluated the feasibility of treating color filter effluent by H2O2/UV pre-oxidation and membrane postseparation for in-house reuse. The effluent qualities were TOC of 5.8–34 mg/L, color of 46–138 ADMI, and conductivity of 1020–3500 μS/cm. Although the RO separation could directly remove TOC, color, and conductivity effectively, the serious fouling problem still existed. Through H2O2/UV pre-oxidation (UV = 13 W, H2O2 = 200 mg/L), organic and biofouling were inhibited to increase the normalized flux decline from 5% to 77%. That is, H2O2/UV pre-oxidation could mitigate the permeate flux decline as well as to improve the water quality for water reuse. 相似文献
99.
从硫脲浸出液中活性炭负载洗脱金是比较困难的,目前在这方面发表的文献并不很多。本文着重研究并讨论了从负载活性炭上洗脱金的不同方法,包括酸性硫脲有机溶液和非有机洗脱液。研究了丙酮、乙腈、丁醇、乙二醚和乙醇5种有机溶剂。研究了不同的硫脲、硫酸和有机溶剂的浓度和温度对洗脱的影响。试验表明了这5种有机溶剂对金的洗脱能力按如下顺序排列: 丁醇>乙腈>乙二醚>乙醇>丙酮当采用5%丁醇,50~100g/L硫脲和50~100g/L硫酸,温度40~60℃时,金的洗脱率可达98~99%,此时活性炭含金降至0.10mg/g以下。对于非有机洗脱液,像硫化钠和硫代硫酸钠,研究表明金的洗脱率主要取决于溶液的浓度和温度,在室温时,1~2mol的硫化钠溶液可以洗脱99%的金。如果溶液的浓度降低至0.5mol,则温度需升至80℃以上才可能获得相同的洗脱率。 相似文献
100.
Ha Vu Thi Thu Nguyen Manh B. Tam Tran Nhu Thu Vu Thi Yen Pham Thi Hai Phong Pham Hong Nhiem Dao Ngoc Hung Le Quoc Hai Tran Quang 《Journal of Applied Electrochemistry》2022,52(3):607-616
Journal of Applied Electrochemistry - In this study, a sensitive and selective electrochemical sensor based on a zirconia oxide-decorated gold nanoflake nanocomposite-modified glassy carbon... 相似文献