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991.
Hwang D Lee H Jang SY Jo SM Kim D Seo Y Kim DY 《ACS applied materials & interfaces》2011,3(7):2719-2725
We report a simple method to prepare hierarchically structured TiO(2) spheres (HS-TiO(2)), using an electrostatic spray technique, that are utilized for photoelectrodes of highly efficient dye-sensitized solar cells (DSSCs). This method has an advantage to remove the synthesis steps in conventional sol-gel method to form nano-sized spheres of TiO(2) nanoclusters. The fine dispersion of commercially available nanocrystalline TiO(2) particles (P25, Degussa) in EtOH without surfactants and additives is electro-sprayed directly onto a fluorine-dopoed tin-oxide (FTO) substrate for DSSC photoelectrodes. The DSSCs of HS-TiO(2) photoelectrodes show high energy conversion efficiency over 10% under illumination of light at 100 mW cm(-2), AM1.5 global. It is concluded from frequency-dependent measurements that the faster electron diffusion coefficient and longer lifetime of HS-TiO(2) than those in nonstructured TiO(2) contribute to the enhanced efficiency in DSSCs. 相似文献
992.
993.
本文设计了一种可实现多射频源复合式能量采集的集成充电电池系统,重点分析了该系统中升压电路和智能管理电路的设计。通过仿真和实验比较了升压电路中普通二极管和肖特基二极管对输出电压的影响,同时讨论了整个系统的转化效率与输出功率。仿真结果表明利用多射频进行能量收集实现了对集成微充电电池充电,实现方案有效可行。 相似文献
994.
This paper reports a theoretical investigation on rapid evaporation of a saline droplet during depressurization. A mathematical model was developed to simulate the droplet temperature variation by considering the ambient pressure change, the heat transfers due to evaporation and convection at the droplet surface, accompanying the heat and mass transfer inside the droplet. The component diffusion and the temperature gradient inside the droplet were mainly discussed by comparing the numerical droplet temperature with the experimental data. The result shows that, the variation of internal concentration is small, while the temperature gradient within the droplet is significant during the evaporation process. In addition, the influencing factors of the droplet temperature variation were analyzed, such as: the final ambient pressure, theinitial salt concentration and the initial droplet temperature. The present model calculations help to understand the thermodynamic process of rapid evaporation of a saline droplet during depressurization. 相似文献
995.
Jin-Hwan Kim Won-Dong Jang Jae-Young Sim Chang-Su Kim 《Journal of Visual Communication and Image Representation》2013,24(3):410-425
A fast and optimized dehazing algorithm for hazy images and videos is proposed in this work. Based on the observation that a hazy image exhibits low contrast in general, we restore the hazy image by enhancing its contrast. However, the overcompensation of the degraded contrast may truncate pixel values and cause information loss. Therefore, we formulate a cost function that consists of the contrast term and the information loss term. By minimizing the cost function, the proposed algorithm enhances the contrast and preserves the information optimally. Moreover, we extend the static image dehazing algorithm to real-time video dehazing. We reduce flickering artifacts in a dehazed video sequence by making transmission values temporally coherent. Experimental results show that the proposed algorithm effectively removes haze and is sufficiently fast for real-time dehazing applications. 相似文献
996.
997.
Dae Sung Chung Dong Hoon Lee Jong Won Park Jaeyoung Jang Sooji Nam Yun-Hi Kim Soon-Ki Kwon Chan Eon Park 《Organic Electronics》2009,10(6):1041-1047
We suggest a novel method for treating the surfaces of dielectric layers in organic field effect transistors (OFETs). In this method, a blend of poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) and dimethylsiloxane (DMS) with a curing agent is spin coated onto the surface of a dielectric substrate, silicon oxide (SiO2), and then thermally cured. X-ray photoelectron spectroscopy, contact angle measurements, and morphology analysis were used to show that the hydrophilic DMS layer is preferentially adsorbed on the SiO2 substrate during the spin coating process. After thermal curing, the bottom DMS layer becomes a hydrophobic PDMS layer. This bottom PDMS layer becomes thinner during curing due to the upward motion of the hydrophobic PDMS molecules. The FET mobility of the cured system was 10?2 cm2/Vs, which is similar to that of polymeric semiconductors on octadecyltrichlorosilane treated SiO2 dielectric layers. We also discuss the possibility of using this blend method to increase the air-stability of polymeric semiconductors. 相似文献
998.
Sanjeev Jain Sheng-Lyang Jang Jhin-Fang Huang 《Analog Integrated Circuits and Signal Processing》2013,76(2):161-166
This letter presents a fully integrated BiCMOS quadrature voltage-controlled oscillator (QVCO). The QVCO consists of two nMOSFET cross-coupled oscillator stacked in series with source degenerated HBT transistors. SiGe HBT introduces low flicker noise compared to CMOS devices. To generate quadrature phase signals with strong coupling strength, the proposed design uses two MOS-coupled LC-tank cores instead of passive device-coupled cores. This source degeneration topology can improve the phase noise performance of the QVCO as compared to the sub-VCO. The proposed QVCO has been implemented with the TSMC 0.18 μm SiGe 3P6M BiCMOS process, can generate quadrature signals in the frequency range of 4.52–5.05 GHz with core power consumption of 5.76 mW at the dc bias of 1.8 V. At 4.53 GHz, phase noise at 1 MHz offset is ?124.52 dBc/Hz. The die area of the fabricated prototype is 0.453 × 0.898 mm2. 相似文献
999.
Jian Wang Jun Li Xinfeng Wang Xiaochuan Mi Shengen Zhang 《Bulletin of Materials Science》2011,34(7):1477-1482
The rapid heating effects on the microstructure, texture and magnetic properties of 3% Si non-oriented electrical steel has been investigated through optical microscopy, X-ray diffraction and Epstein frame. The results show that recrystallized grains were refined with increased heating rate, caused by the nucleation rate increase, which is faster than the growth rate due to rapid hearting. With the heating rate increase, the characteristic {111} recrystallization fibre of cold-rolled steel was depressed, but the beneficial 〈001〉//RD and 〈001〉//ND fibres were significantly strengthened. Although the grain-size decreases with heating rate increasing, the optimal magnetic properties can also be obtained through the recrystallized grain-size and texture optimization by rapid heating. In this research, we find the magnetic properties optimization can be obtained when annealed with 100°C/s heating rate: the core loss (P 1·5/50) decrease 13% and the magnetic induction (B 50) increase 3%. 相似文献
1000.
Sung‐Ae Jang Yoon‐Ji Shin Kyung Bin Song 《International Journal of Food Science & Technology》2011,46(3):620-625
To develop a packaging film for ‘Maehyang’ strawberries, an edible film containing antimicrobial grapefruit seed extract (GSE) was manufactured. Addition of GSE to the rapeseed protein–gelatin (RG) film inhibited the growth of pathogenic bacteria such as Escherichia coli O157:H7 and Listeria monocytogenes. Packaging of ‘Maehyang’ strawberries with the RG film containing 1.0% GSE decreased the populations of total aerobic bacteria and of yeast and moulds in the strawberries by 1.03 and 1.34 log CFU g?1, respectively, after 14 days of storage, compared to that of the control. Sensory evaluation of the GSE‐RG film‐packaged strawberries produced better sensory scores than did the control. These results suggest that RG film containing GSE can be used to package strawberries and to extend shelf life. 相似文献