电阻率可调的含钛碳化硅纤维的制备与性能研究

以Ｔｉ（ＯＢｕ）４与低分子量聚硅烷（ＬＰＳ）为原料合成不同含钛量的聚钛碳硅烷,经熔融纺丝、空气不熔化、高温烧结制备出力学性能良好、电阻率为１０３～１０Ω·ｃｍ的Ｓｉ—Ｔｉ—Ｃ—Ｏ纤维。通过ＩＲ、ＧＰＣ、ＶＰＯ、ＸＰＳ等分析手段系统研究了钛含量对纤维的制备、结构及其电性能的影响。     

空芯光子晶体光纤熔接技术研究

空芯光子晶体光纤(HC-PCF)因其利用纤芯的空气导光而具有高损伤阈值、低损耗、低色散、低非线性等优点。此外,HC-PCF纤芯中空气的折射率温度系数、Verdet系数、Kerr系数远小于石英,在光纤陀螺中有独特的优势。但是在向实际应用迈进的过程中,必须要解决HC-PCF与普通单模光纤以及自身简便、低损耗的熔接问题。基于热致扩芯技术和过渡光纤两种模场匹配方法,研究了HC-PCF和普通单模光纤之间的熔接问题,将两者的熔接损耗由直接熔接的1.4dB降至0.73dB。此外,研究了HC-PCF与其自身的熔接,通过两步放电熔接法,得到高强度低损耗的熔点,熔接损耗为0.52dB。     

A new approach for pulse amplitude measurement using Lagrange’s interpolation for radiation or particle detectors

In radiation detector signal processing, usually, the charge-sensitive preamplifier converts the small charge signal coming from the semiconductor-based detector into voltage form and then the signal is further amplified to measure the energy of the incoming radiation. The voltage pulse from a charge-sensitive preamplifier (CSPA) is amplified using a shaping amplifier which reduces the signal bandwidth. To achieve better energy resolution, precise measurement of the peak amplitude of shaping amplifier output is required. The signal processing methods are available in which the signal from the charge-sensitive preamplifier can be directly digitized using high-speed Analog to Digital Converters (ADC), and then further signal processing such as gain and shaping is carried out inside the Field Programmable Gate Arrays (FPGA). For multiple detector systems, digital signal processing methods are quite difficult to implement in Field Programmable Gate Arrays (FPGA). In this context, The development of an alternative technique is initiated that uses a charge-sensitive preamplifier, shaping amplifier, low sampling analog-to-digital converter, and FPGA, where LaGrange’s interpolation technique is implemented in FPGA to precisely measure the peak of the analog pulse. In this paper, the comparison of the proposed method with other pulse amplitude measurement techniques is discussed. Results show that the implemented technique gives similar energy resolution compared to digital pulse processing and standard peak detector-based techniques.