一种双折射平衡型光纤温度传感器的研究

提出了一种双折射平衡型光纤高温传感系统。这种系统是通过检测光偏振态的变化来测量温度特性的。用两块蓝宝石单晶片作为探头中的敏感元件,它们首尾相接,第一块晶体的慢轴与第二块晶体的快轴相连。两块晶体的双折射相互平衡,提高了传感器的灵敏度和准确性,温度的测量范围可达２０００℃以上。精度可达０．３５％,这种系统可广泛用于航空发动机进口温度测量。本文从物理模型和数学分析上证实了这种传感器的可行性。并通过计算机     

基于16QAM的光OFDM发射机的设计与实现

提出并实现了一种基于16QAM的光OFDM发射机,通过对发射机机各个模块的功能仿真验证分析,本发射机具有准确性、易实现和资源消耗少等优点。     

专创融合驱动的移动通信课程教学改革

“移动通信”是通信工程专业一门重要的专业课程,本文聚焦专创融合驱动的“移动通信”课程教学改革,首先分析了在专创融合背景下当前授课所存在的问题,然后提出基于CDIO+PBL的教学模式,将“移动通信”课程内容与课程思政、创新教育有机融合,实现了对学生专业实践能力和创新思维意识的稳步培养与提升,促进专创融合教育的落实。     

精确模型化学中MPn微扰外推的一个问题

通过对ＢＨ、ＡｌＨ、ＢＦ和ＡｌＦ的高级别ａｂ ｉｎｉｔｉｏ势能曲线计算和理论分析,发现在分子的几何构型偏离平衡时,由于参考态级成不充分的问题,Ｈａｒｔｒｅｅ－Ｆｏｃｋ单参考态的ＭＰｎ微扰计算可能给出错误的能量值。从而表明,目前的精确模型化学方法（Ｇ１、Ｇ２、Ｇ３和ＣＢＳ系列）中用ＭＰｎ微扰外推的办法拟合高级别ａｂ ｉｎｉｔｉｏ,对偏离平衡构型体系（如动力学研究中的过渡态、中间体等）的能量计算,在一     

Effect of heavy ion irradiation on the interface traps of AlGaN/GaN high electron mobility transistors

AlGaN/GaN high electron mobility transistors (HEMTs) were irradiated with heavy ions at various fluences. After irradiation by 2.1 GeV¹⁸¹ Ta³²⁺ ions, the electrical characteristics of the devices significantly decreased. The threshold voltage shifted positively by approximately 25% and the saturation currents decreased by approximately 14%. Defects were induced in the band gap and the interface between the gate and barrier acted as tunneling sites, which increased the gate current tunneling probability. According to the pulsed output characteristics, the amount of current collapse significantly increased and more surface state traps were introduced after heavy ion irradiation. The time constants of the induced surface traps were mainly less than 10 μs.     

斜切蓝宝石衬底MOCVD生长GaN薄膜的透射电镜研究

利用MOCVD技术在斜切角度为0.3°的c面蓝宝石衬底上生长了非故意掺杂 GaN 薄膜, 并采用透射电子显微镜对材料的质量和材料内部缺陷进行了分析. 研究发现斜切蓝宝石衬底上外延的GaN材料中,位错在距离衬底0.8 μm附近大量湮灭, 同时位错扎堆出现.基于上述现象, 提出了斜切衬底上GaN材料中位错的湮灭机制, 解释了斜切衬底能够提高GaN晶体质量的原因.     

Neutron irradiation effects on AlGaN/GaN high electron mobility transistors

AlGaN/GaN high electron mobility transistors (HEMTs) were exposed to 1 MeV neutron irradiation at a neutron fluence of 1 × 10¹⁵ cm^-2. The dc characteristics of the devices, such as the drain saturation current and the maximum transconductance, decreased after neutron irradiation. The gate leakage currents increased obviously after neutron irradiation. However, the rf characteristics, such as the cut-off frequency and the maximum frequency, were hardly affected by neutron irradiation. The AlGaN/GaN heterojunctions have been employed for the better understanding of the degradation mechanism. It is shown in the Hall measurements and capacitance-voltage tests that the mobility and concentration of two-dimensional electron gas (2DEG) decreased after neutron irradiation. There was no evidence of the full-width at half-maximum of X-ray diffraction (XRD) rocking curve changing after irradiation, so the dislocation was not influenced by neutron irradiation. It is concluded that the point defects induced in AlGaN and GaN by neutron irradiation are the dominant mechanisms responsible for performance degradations of AlGaN/GaN HEMT devices.     

基于EBG结构的新型超宽带低噪声电源/地平面设计

将电磁带隙（EBG）结构加载在电源/地平面之间,依据理论分析对模型结构以及各项参数进行优化.设计出抑制深度为-80 dB、禁带宽度为10 GHz的超宽禁带电源/地平面,在拥有优良抑制电磁干扰能力的同时,也保证了信号的完整性.在禁带内,该平面可以有效地抑制电路之间特别是共用电源/地平面的数字电路与射频电路之间所引起的电磁干扰.仿真实验表明,该设计取得了理想的效果.     

一种基于模糊逻辑的外环功率控制方法

本文针对cdma2000系统的通信链路，提出 了一种适应于前反向链路的外环功率控制的方法，它根据模糊控制的理论，建立了一系列的模糊规则，通过可变的调整步长，能对不同的通信环境作出灵敏的反应。与传统的方法相比，该方法提高了控制的精度，最大限度地减少了内环的发射功率，从而减少了系统的干扰，增加了系统的稳定性，提高了系统容量。仿真结果也证明了此方法的上述优越性能。     

感应耦合等离子体刻蚀p-GaN的表面特性

研究了p-GaN材料经感应耦合等离子体(ICP)刻蚀后的表面特性，并用不同的方法对刻蚀表面进行处理.利用原子力显微镜(AFM)和X射线光电子能谱(XPS)对刻蚀样品进行分析，并在样品表面制作Ni/Au电极，进行欧姆接触特性的测试.实验结果表明了NaOH溶液处理表面对改善材料表面和欧姆接触特性是比较有效的.