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81.
Yow-Jon Lin Chia-Lung Tsai Chia-Jyi Liu Lance Horng Yu-Tai Shih Mu-Shan Wang Chuan-Sheng Jhang Chao-Shien Huang 《Journal of Sol-Gel Science and Technology》2009,52(1):109-112
Co0.2Mg
x
Zn0.8−x
O films prepared with different molar ratio of magnesium acetate to zinc acetate were deposited on substrates by the sol–gel
technique. X-ray diffraction, photoluminescence (PL) and ferromagnetism measurements were used to characterize the Co0.2Mg
x
Zn0.8−x
O diluted magnetic semiconductors. The acceptor-like defects were determined in the PL band and the intensity of the acceptor-related
PL increased with increasing Mg concentration. Therefore, an increase in the number of the acceptor-like defects (zinc vacancies
especially) in the Co0.2Mg
x
Zn0.8−x
O film may lead to the enhancement of the magnetic properties. It is worth noting that changes in Mg concentration and the
number of the acceptor-like defects are important issues for producing strong ferromagnetism Co0.2Mg
x
Zn0.8−x
O films prepared by the sol–gel method. 相似文献
82.
Local binary pattern (LBP) operators, which measure the local contrast within a pixel's neighborhood, have been successfully applied to texture analysis, visual inspection, and image retrieval. In the paper, we present a novel semi-fragile spatial watermarking method based on LBP operators by using the local pixel contrast for the embedding and extraction of watermarks. We also propose a general framework for multi-level image watermarking. Experimental results show that the proposed watermarking methods are robust against commonly-used image processing operations, such as additive noise, luminance change, contrast adjustment, color balance, and JPEG compression. At the same time, they achieve good invisibility, fragility, and image tamper detection and localization with less computational cost. 相似文献
83.
Moon Gi Cho Sung K. Kang Sun-Kyoung Seo Da-Yuan Shih Hyuck Mo Lee 《Journal of Electronic Materials》2009,38(11):2242-2250
The effects of the addition of Zn to Sn-0.7Cu solders are investigated. The study is focused on the interfacial reactions,
microstructures, and mechanical properties after reaction with Ni-P under bump metallurgies (UBMs). The Zn contents in Sn-0.7Cu-xZn are varied as 0.2, 0.4, and 0.8 (in wt.% unless otherwise specified). In the reaction with Ni-P UBM during thermal aging
at 150°C for 1000 h, (Cu,Ni)6Sn5 intermetallic compounds (IMCs) are formed at the Sn-0.7Cu/UBM interface, whereas Zn is incorporated into IMCs to form (Cu,Ni,Zn)6Sn5 in the Zn-doped solders. As the Zn content increases, the interfacial IMC thickness is reduced. A total reduction of about
40% in IMC thickness was observed for the 0.8% Zn-doped Sn-Cu. The same IMC particles are also observed in the matrix of each
solder. In Sn-0.7Cu, (Cu,Ni)6Sn5 particles are coarsened during aging, while (Cu,Ni,Zn)6Sn5 particles in the Zn-added solders are less coarsened and remain much smaller than (Cu,Ni)6Sn5. The growth rate of (Cu,Ni)6Sn5 during thermal aging is significantly suppressed by the addition of Zn. Consequently, after reaction with Ni-P UBM, the Zn-doped
solders exhibit a thermally stable microstructure as measured by hardness and shear strength. 相似文献
84.
Chen Kai-Huang Cheng Chien-Min Shih Chia-Chi Tsai Jen-Hwan 《Applied Physics A: Materials Science & Processing》2011,103(4):1173-1177
In this study, the ferroelectricity of as-deposited Bi3.9La0.1Ti2.9V0.1O12 (BLTV), Bi3.9Ti2.9V0.1O12 (BTV), and Bi4Ti3O12 (BIT) thin films was prepared and compared by rf magnetron sputtering technology. For the BLTV, BTV, and BIT thin films deposited
on Pt/Ti/SiO2/Si and SiO2/Si substrate, the physical and electrical characteristics of lanthanum doped BTV (BLTV) were better than those of BIT and
BTV thin films. Regarding the physical properties, the micro-structure of as-deposited BTV and BLTV thin films were obtained
and compared by XRD patterns and SEM images. The BLTV and BTV thin films were also exhibited clear the ferroelectricity. The
remanent polarization (P
r
) of as-deposited BLTV thin films was 11 μC/cm2 as the measured frequency of 100 kHz. It was higher than those of BTV thin films. Finally, the polarization of BLTV thin
film capacitor decreased by 9%, while that of the BTV decreased by 15% after the fatigue test with 109 switching cycles. 相似文献
85.
Fu Yuan Shih Chien Hung Yeh Chi Wai Chow Chia Hsuan Wang Sien Chi 《Optical Fiber Technology》2010,16(1):46-49
In this investigation we propose and demonstrate a wavelength widely tunable laser source employing a self-injected Fabry–Perot laser diode (FP-LD) for long-reach wavelength-division-multiplexed passive optical network (WDM-PON). By using a tunable bandpass filter and an optical circulator inside the gain cavity, a stable and single-longitudinal-mode (SLM) laser output is achieved. Besides, the proposed laser sources are directly modulated at 2.5 Gb/s for both downlink and uplink transmissions of 85 km single mode fiber (SMF) in PON without dispersion compensation. 相似文献
86.
Chia-Chi Shih Yu-Jen Chen Sean Wu Cheng-Che Tsai I-Min Jiang 《Optics Communications》2009,282(19):3977-3981
This study presents an integrated device that consists of a directional coupler and an electro-optic switch. The device is designed to include a nematic liquid crystal cell, comprising a grating-like electrode. Applying the appropriate voltage to the cell yields a periodically distributed refractive index. An incident polarized beam will couple to an adjacent channel if it is parallel to the channel. The coupling efficiency is controlled by applied voltage. An obliquely injected polarized beam will be reflected and refracted in the channel, and propagated along a curved path. The route of the beam can be controlled by applying the voltage. A multiport routing was achieved for voltage modulation. In addition, the distribution of refractive index is also investigated by employing conoscopic technique experimentally and numerically. 相似文献
87.
Chao-Fang Shih Bhuvana Krishnaswamy Yubing Jian Raghupathy Sivakumar 《Wireless Networks》2018,24(1):89-112
The ubiquitous adoption of WiFi introduces large diversity in types of application requirements and topological characteristics. Consequently, considerable attention is being devoted to making WiFi networks controllable without compromising their scalability. However, the main MAC protocol of WiFi, distributed coordination function (DCF), is a contention-based protocol using random backoff. Thus, operating under DCF, the access of channel is hard to control and nonpredictable. In order to provide controllability of channel access in WiFi, we propose Rhythm, a MAC protocol that achieves scheduled WiFi efficiently using distributed contention. By achieving scheduled WiFi, channel access can be controlled by manipulating the schedule decision. We evaluate the performance of Rhythm through analysis, experiments, and case-studies. 相似文献
88.
Sung K. Kang Donovan Leonard Da-Yuan Shih Lynne Gignac D. W. Henderson Sungil Cho Jin Yu 《Journal of Electronic Materials》2006,35(3):479-485
The near-ternary eutectic Sn-Ag-Cu alloys have been identified as leading Pb-free solder candidates to replace Pb-bearing
solders in microelectronic applications. However, recent investigations on the processing behavior and solder joints reliability
assessment have revealed several potential reliability risk factors associated with the alloy system. The formation of large
Ag3Sn plates in Sn-Ag-Cu joints, especially when solidified in a relatively slow cooling rate, is one issue of concern. The implications
of large Ag3Sn plates on solder joint performance and several methods to control them have been discussed in previous studies. The minor
Zn addition was found to be effective in reducing the amount of undercooling required for tin solidification and thereby to
suppress the formation of large Ag3Sn plates. The Zn addition also caused the changes in the bulk microstructure as well as the interfacial reaction. In this
paper, an in-depth characterization of the interfacial reaction of Zn-added Sn-Ag-Cu solders on Cu and Au/Ni(P) surface finishes
is reported. The effects of a Zn addition on modification of the interfacial IMCs and their growth kinetics are also discussed. 相似文献
89.
Ching-Yuan Wu Shui-Yuan Yang Hsing-Hai Chen Fang-Churng Tseng Chih-Tay Shih 《Solid-state electronics》1984,27(7):651-658
Based on the two-dimensional Poisson equation, the surface potential distribution along the surface channel of a MOSFET has been analytically derived by assuming negligible source and drain junction depths and its minimum potential is then used to determine the threshold voltage. The existence of a minimum surface potential point along the channel of a MOSFET under an applied drain bias is consistent with the numerical results of the two-dimensional analysis. The effects of finite source and drain junction depths have been elegantly included by modifying the depletion capacitance under the gate and the resulted threshold voltage model has been compared to the results of the two-dimensional numerical analysis. It has been shown that excellent agreement between these results has been obtained for wide ranges of substrate doping, gate oxide thickness, channel length (< 1 μm), substrate bias, and drain voltage. Moreover, comparisons between the developed model and the existing experimental data have been made and good agreement has been obtained. The major advantages of the developed model are that no iterations and no adjustable fitting parameters are required. Therefore, this simple and accurate threshold voltage model will become a useful design tool for ultra short channel MOSFETs in future VLSI implementation. 相似文献
90.
The disclination model of high angle grain boundaries proposed before is used to understand the energy-angle relations between cusp misorientations. It is found that the model predicts the correct relationship within experimental error with only one adjustable parameter which resembles the Burgers vector of dislocations at low angles. Experimental data for [100] symmetric tilt boundaries in Cu and Al and for [110] symmetric tilt boundaries in Al are used for illustration. 相似文献