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991.
992.
本文计算了GaP/Au 反光镜, GaP/SiO2/Au 三层ODR and GaP/ITO/Au 三层ODR的反射率随角度的变化值。制作了GaAs衬底的AlGaInP LED,Au反光镜、SiO2 ODR和ITO ODR的薄膜AlGaInP LED。在20mA下,四种样品光输出功率分别为1.04mW, 1.14mW, 2.53mW and 2.15mW。制作工艺退火后,Au扩散使Au/GaP反光镜的反射率降至9%。1/4波长的ITO和SiO2透射率不同造成了两种薄膜LED光输出功率不同。ITO ODR中加入Zn可以大大降低LED的电压,但并不影响LED的光输出。 相似文献
993.
Jyi-Lai Shen Hau-Min Huang Yueh-Chien Lee Chia-Chih Huang Huang-Cuang Lin Chin-Yuan Lin 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(1):44-50
To form a low noise figure and uniform shortpass band in optical fiber communications an improved automatic filtered power
control (AFPC) pumping method is proposed here. A modulated single laser signal was entered in a closed feedback loop, in
which the erbium-doped fiber amplifier (EDFA) was used as a part of the AFPC loop. Owing to the constant filtered signal and
the quadrature phase shift delay inside the feedback loop, an optical pass band was uniformly formed. This EDFA attains high
performance with a low noise figure simultaneously. The method was successfully applied to the fabrication of practical 12.0
m length of erbium-doped fiber pumped at 980 nm wavelength and 20 dBm power. Experiments prove that the signal gain of the
loop remain flat in the range of 18.2 to 22.4 dB with a worst case error of ±0.5 dB and the noise figure was reduced by 2.2
dB at optimal, which correspond to a shortpass range of 40 nm band pass from 1525 nm to 1565 nm in wavelength. Of course,
it should be possible to extent the system performance to all pumping configurations for semiconductor optical amplifiers.
This provides the simplest and most economical way to transmit a well-defined band of modulated laser signal and to reject
all other unwanted radiation. 相似文献
994.
995.
循环码的周期分布的新的计算公式 总被引:17,自引:1,他引:17
本文在[1]文的基础上进一步分析了循环码的周期分布的性质,给出了新的计算方法和公式,并且确定了一些熟知的循环码的周期分布。 相似文献
996.
用远红外HCN激光干涉仪测量等离子体电子密度 总被引:2,自引:0,他引:2
在大多数托克马克上,远红外激光干涉仪是等离子体诊断中的一种重要的装置。本文介绍了用远红外HCN激光干涉仪测量等离子体电子密度的原理和激光干涉仪结构,并给了了首次在我国第一以大型超导托克马克HT-7装置上测到的中心弦等离子体电子平均密度。 相似文献
997.
Quality-of-Service (QoS) performance and connection admission control (CAC) for heterogeneous services in wireless multiple access networks are investigated. The heterogeneous services include constant bit rate (CBR), variable bit rate (VBR) and available bit rate (ABR) services. Multiple access control is handled by a polling-based scheme with non-preemptive priority. Tight delay variation (jitter) bounds for CBR connections and delay bounds for VBR connections are derived. A CAC scheme based on the derived bounds is developed. The CAC makes use of user mobility information to reserve an appropriate amount of system resources for potential handoff connections to achieve low handoff connection dropping rate (HCDR). Simulation results show that the proposed CAC scheme can achieve both low HCDR and high resource utilization. 相似文献
998.
999.
Ying Yang J. N. Balaraju Yizhong Huang Yee Yan Tay Yiqiang Shen Zviad Tsakadze Zhong Chen 《Journal of Electronic Materials》2014,43(11):4103-4110
The voids formed in the Ni3P layer during reaction between Sn-based solders and electroless Ni–P metallization is an important cause of rapid degradation of solder joint reliability. In this study, to suppress formation of the Ni3P phase, an electrolessly plated Ni–Sn–P alloy (6–7 wt.% P and 19–21 wt.% Sn) was developed to replace Ni–P. The interfacial microstructure of electroless Ni–Sn–P/Sn–3.5Ag solder joints was investigated after reflow and solid-state aging. For comparison, the interfacial reaction in electroless Ni–P/Sn–3.5Ag solder joints under the same reflow and aging conditions was studied. It was found that the Ni–Sn–P metallization is consumed much more slowly than the Ni–P metallization during soldering. After prolonged reaction, no Ni3P or voids are observed under SEM at the Ni–Sn–P/Sn–3.5Ag interface. Two main intermetallic compounds, Ni3Sn4 and Ni13Sn8P3, are formed during the soldering reaction. The reason for Ni3P phase suppression and the overall mechanisms of reaction at the Ni–Sn–P/Sn–3.5Ag interface are discussed. 相似文献
1000.