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61.
Byung Sik Yoon Jae Won Kim Won Myoung Lee Seok Jin Jang Song In Choi Myoung Seob Lim 《ETRI Journal》1997,19(3):242-258
The Qualcomm code excited linear prediction (QCELP) speech coder was adopted to increase the capacity of the CDMA Mobile System (CMS). In this paper, we implemented the QCELP speech coding algorithm by using TMS320C50 fixed point DSP chip. Also the fixed point simulation was done with C language. The computation complexity of QCELP on TMS320C50 was about 33 MIPS and program size was 10k words and data memory was 4k words. In the normal call test on the CMS, where mobile to mobile call test was done in the bypass mode without double vocoding, mean opinion score for the speech quality was 3.11. 相似文献
62.
Seong Bo Kim Myoung Jae Choi Dae Chul Park Kyu Wan Lee 《Korean Journal of Chemical Engineering》1991,8(3):137-142
The HDN of quinoline was investigated for the purpose of utilizing the hydrogen which could be generated from the water gas
shift reaction (WGSR). The optimum concentration of hydrogen were produced under 1.5 of water to carbon monoxide mole ratio
and 6 hr-1 of space velocity at 390°C of temperature during WGSR over Co-Mo/γ-Al2O3 catalyst. The HDN reactions were compared by using the pure hydrogen and the nascent hydrogen which was produced by a WGSR.
The pure hydrogen gave much higher activity in the overall HDN reaction than the nascent hydrogen. However, kinetic study
on the hydrogenation, hydrogenolysis and cracking reaction steps showed that only at the cracking reaction step the nascent
hydrogen gave the superiority to the pure hydrogen. This inferiority of the nascent hydrogen in overall HDN reaction could
be resulted from the negative effect of water which should be accompanied during WGSR. The conversion of the HDN reaction
was maximized at the water pressure of 150 kpa. 相似文献
63.
In Baek Park Young Myoung Ha Seok Hee Lee 《The International Journal of Advanced Manufacturing Technology》2010,46(1-4):151-161
Microstereolithography is a microfabrication technology done in a layer-by-layer fashion. It is useful to fabricate a microstructure with both a high aspect ratio and a complex shape. Projection microstereolithography is suitable for microstructure array fabrication due to the fast process time using patterned light irradiation. However, nonuniform light intensity on the resin surface deteriorates the fabrication precision. This research proposes the cross-section segmentation for uniform exposure energy on the resin surface. Each subsection consisting of a cross-section is separately converted into an image file. The estimated exposure time of each subsection is stored in a text file and used during the fabrication. Finally, several microstructure arrays are fabricated to verify this method. 相似文献
64.
Dae-Jin Yang Su-Chul Yang Jae-Min Hong Hyunjung Lee Il-Doo Kim 《Journal of Electroceramics》2010,24(3):200-204
For a working electrode in dye-sensitized solar cells (DSSCs), an anatase TiO2 electrode with a hollow hemisphere structure (with diameters of 0.4, 1.5, and 5.0 μm) was fabricated using colloidal templating
and RF-sputtering techniques. The experimental results of a short-circuit current density of 1.96 mA/cm2, an open-circuit voltage of 0.73 V, and a power conversion efficiency (AM 1.5) of 0.67% were obtained with a shell thickness
of 300 nm, a hemisphere diameter of 0.4 μm, and a 100 nm thick blocking layer. The microstructural features, i.e. hemisphere
diameter and shell thickness, played an important role in promoting the charge-collection ability. 相似文献
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69.
Hyunmin Kim Minjeong Seo Jong‐Woo Kim Do‐Kyun Kwon Song‐Ee Choi Jin Woong Kim Jae‐Min Myoung 《Advanced functional materials》2019,29(24)
Due to the increasing interest in wearable devices, flexible and stretchable film heaters have been widely studied, as alternatives to heaters with conventional rigid shapes. Herein, a highly stretchable film heater (SFH) based on the silver nanowire (Ag NW)–single‐walled carbon nanotube composite with a thermochromic display on a polydimethylsiloxane (PDMS) substrate is successfully fabricated. The SFH shows excellent electrical conductivity, high mechanical stretchability, and outstanding reliability, with no significant degradation after 10 000 stretching cycles under tensile strain. The SFH can be heated to the target temperature (≈60 °C) within 30 s at a low applied voltage. In addition, a thermochromic display is fabricated to help prevent the risk of low‐temperature burns. Red (R), green (G), and blue (B) thermochromic microparticles (TMPs) are synthesized using drop‐based microfluidic technology. The TMPs show RGB colors at room temperature but change to a white color above a certain temperature. The TMPs are arrayed into a PDMS stencil on the basis of their particle sizes using the rubbing technique. The micropatterned thermochromic display, which functions as a visual alarm, combined with the SFH can pave the way for the development of thermotherapy pads for next‐generation wearable devices in the medical field. 相似文献
70.
Electrochromic materials reversibly change colors by redox reactions depending on the oxidation states. To utilize electrochromic materials for active‐matrix display applications, an electrochromic display (ECD) requires simultaneous implementation of various colors and a fine‐pixelation process. Herein, flexible and transparent ECDs with simultaneously implementable subpixelated EC gels by sequential multiple patterning are successfully demonstrated. Ionic liquid‐based EC gels of monoheptyl‐viologen, diheptyl‐viologen (DHV), and diphenyl‐viologen (DPV) are used to create the colors of ECDs: magenta, blue, and green, respectively. Especially, to realize an improved green color, DHV–DPV composite gels are synthesized. Three EC gels exhibit stable properties without degradation during repetitive operation. Moreover, a transmittance greater than 90% is maintained in a bleached state, which is sufficient for application as a transparent display. The subpixelation process for multicolored‐flexible ECDs is designed to facilitate both easy fabrication and rapid operation with various patterns at low cost. The subpixelated EC gels using a film mask can be implemented to a minimum size of 200 µm. Furthermore, the subpixelated flexible ECDs exhibit high durability even after 1000 cycles of mechanical bending tests at a bending radius of 10 mm. Therefore, these EC materials can be used directly for flexible and transparent active‐matrix displays. 相似文献