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111.
The effects of the surface energy of polymer gate dielectrics on pentacene morphology and the electrical properties of pentacene field‐effect transistors (FETs) are reported, using surface‐energy‐controllable poly(imide‐siloxane)s as gate‐dielectric layers. The surface energy of gate dielectrics strongly influences the pentacene film morphology and growth mode, producing Stranski–Krastanov growth with large and dendritic grains at high surface energy and three‐dimensional island growth with small grains at low surface energy. In spite of the small grain size (≈ 300 nm) and decreased ordering of pentacene molecules vertical to the gate dielectric with low surface energy, the mobility of FETs with a low‐surface‐energy gate dielectric is larger by a factor of about five, compared to their high‐surface‐energy counterparts. In pentacene growth on the low‐surface‐energy gate dielectric, interconnection between grains is observed and gradual lateral growth of grains causes the vacant space between grains to be filled. Hence, the higher mobility of the FETs with low‐surface‐energy gate dielectrics can be achieved by interconnection and tight packing between pentacene grains. On the other hand, the high‐surface‐energy dielectric forms the first pentacene layer with some voids and then successive, incomplete layers over the first, which can limit the transport of charge carriers and cause lower carrier mobility, in spite of the formation of large grains (≈ 1.3 μm) in a thicker pentacene film. 相似文献
112.
Shin‐ichiro Sato Hitoshi Sai Takeshi Ohshima Mitsuru Imaizumi Kazunori Shimazaki Michio Kondo 《Progress in Photovoltaics: Research and Applications》2013,21(7):1499-1506
This paper reports temperature influence on radiation degradation of hydrogenated amorphous silicon (a‐Si : H) solar cells. Degradation behaviors of a‐Si : H solar cells irradiated with protons at 331 K are compared with that at 298 K (room temperature). Variations with time in the post‐irradiation electrical properties are also investigated. It is found that the radiation degradation of the electrical properties at 331 K is significantly smaller than that at room temperature. Also, all the electrical properties (short‐circuit current, open‐circuit voltage, output maximum, and fill factor) recover with time after irradiation even at room temperature. The characteristic time of thermal annealing of short‐circuit current is larger as the temperature is higher. These results indicate that temperature during irradiation and elapsed time from irradiation to measurement is an important parameter for radiation degradation of a‐Si : H solar cells. Therefore, these parameters should be controlled in conducting the ground radiation tests. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
113.
Protein extraction solutions such as aqueous solutions of sodium hydroxide (0.1 and 0.2 %), sodium lauryl sulfate (SLS, 1.2 %) containing sodium sulfite (0.12 %), and dodecylbenzene sulfonate (DoBS, 1.2 %) containing sodium sulfite (0.12 %) were compared in their protein removal efficiencies during isolation of starch from a rice flour (Ilpumbyo, a nonwaxy Korean rice variety). In addition, the pasting properties of the isolated starch was compared. More than 80 % of the flour protein was extracted in 1 h by stirring the dispersion (1:3, w/v) at room temperature. Repeating the extractions (1 or 2 h for each step) with fresh solution significantly increased the protein removal efficiency. When the extraction in 0.2 % NaOH was repeated four times (1 h for each step) at 25°C, the residual protein content in the isolated rice starch was 0.9 % (DB), equivalent to 86 % removal of the rice protein. Raising the extraction temperature slightly increased the protein solubility, but starch loss also became significant. Among the solutions, DoBS was most effective in removing rice protein whereas SLS was least. The residual protein content had a critical role in determining the pasting characteristics of the isolated starch, showing a negative correlation to the peak viscosity of the starch paste, but a positive correlation to the pasting temperature. 相似文献
114.
115.
Young‐Tak Han Jang‐Uk Shin Duk‐Jun Kim Sang‐Ho Park Yoon‐Jung Park Hee‐Kyung Sung 《ETRI Journal》2003,25(6):535-537
We propose a rigorous 2D approximation technique for the 3D waveguide structures; it can minimize the well‐known approximation errors of the commonly used effective index method. The main concept of the proposed technique is to compensate for the effective cladding index in the equivalent slab model of the original channel waveguide from the modal effective index calculated by the nonuniform 2D finite difference method. With simulations, we used the proposed technique to calculate the coupling characteristics of a directional coupler by the 2D beam propagation method, and the results were almost exactly the same as the results calculated by the 3D beam propagation method. 相似文献
116.
Lan Kim Moo Whan Shin 《Components and Packaging Technologies, IEEE Transactions on》2007,30(4):632-636
Thermal transient measurements of high power GaN-based light-emitting diodes (LEDs) with multichip designs are presented and discussed in the paper. Once transient cooling curve was obtained, the structure function theory was applied to determine the thermal resistance of packages. The total thermal resistance from junction to ambient considering optical power is 19.87 K/W, 10.78 K/W, 6.77 K/W for the one-chip, two-chip and four-chip packages, respectively. The contribution of each component to the total thermal resistance of the package can be determined from the cumulative structure function and differential structure function. The total thermal resistance of multichip packages is found to decrease with the number of chips due to parallel heat dissipation. However, the effect of the number of chips on thermal resistance of package strongly depends on the ratio of partial thermal resistance of chip and that of slug. Therefore, an important thermal design rule for packaging of high power multichip LEDs has been analogized. 相似文献
117.
To improve the steady state estimation error due to mismatched uncertainty, a variable structure observer for mismatched uncertain dynamical systems is proposed by using the generalised matrix inverse. Simulation results show that the estimation error is largely decreasing using the proposed observer.<> 相似文献
118.
Changhwan Shin Xin Sun Tsu-Jae King Liu 《Electron Devices, IEEE Transactions on》2009,56(7):1538-1542
A study of random-dopant-fluctuation (RDF) effects on the trigate bulk MOSFET versus the planar bulk MOSFET is performed via atomistic 3D device simulation for devices with a 20 nm gate length. For identical nominal body and source/drain doping profiles and layout width, the trigate bulk MOSFET shows less threshold voltage (Vth) lowering and variation. RDF effects are found to be caused primarily by body RDF. The trigate bulk MOSFET offers a new method of VTH adjustment, via tuning of the retrograde body doping depth, to mitigate tradeoffs in VTH variation and short-channel effect control. 相似文献
119.
Jang‐Uk Shin Young‐Tak Han Sang‐Pil Han Sang‐Ho Park Yongsoon Baek Young‐Ouk Noh Kang‐Hee Park 《ETRI Journal》2009,31(6):770-777
We have developed a fully functional reconfigurable optical add‐drop multiplexer (ROADM) switch module using a polymer integrated photonic lightwave circuit technology. The polymer variable optical attenuator (VOA) array and digital optical switch array are integrated into one polymer PLC chip and packaged to form a 10‐channel VOA integrated optical switch module. Four of these optical switch modules are used in the ROADM switch module to execute 40‐channel switching and power equalization. As a wavelength division multiplexer (WDM) filter device, two C‐band 40‐channel athermal arrayed waveguide grating WDMs are used in the ROADM module. Optical power monitoring of each channel is carried out using a 5% tap PD. A controller and firmware having the functions of a 40‐channel switch and VOA control, optical power monitoring, as well as TEC temperature control, and data communication interfaces are also developed in this study. 相似文献
120.
Yoo Seung Song Shin Kyung Lee Jeong Woo Lee Do Wook Kang Kyoung Wook Min 《ETRI Journal》2019,41(6):703-714
Many use cases have been presented on providing convenience and safety for vehicles employing wireless access in vehicular environments and long‐term evolution communication technologies. As the 70‐MHz bandwidth in the 5.9‐GHz band is allocated as an intelligent transportation system (ITS) service, there exists the issue that vehicular communication systems should not interfere with each other during their usage. Numerous studies have been conducted on adjacent interfering channels, but there is insufficient research on vehicular communication systems in the ITS band. In this paper, we analyze the interference channel performance between communication systems using distribution functions. Two types of scenarios comprising adjacent channel interference are defined. In each scenario, a combination of an aggressor and victim network is categorized into four test cases. The minimum requirements and conditions to meet a 10% packet error rate are analyzed in terms of outage probability, packet error rate, and throughput for different transmission rates. This paper presents an adjacent channel interference ratio and communication coverage to obtain a satisfactory performance. 相似文献