掺锗单模光纤布拉格光栅γ辐照损伤实验

为开发光纤布拉格光栅在空间环境温度及应变的测量的应用,有必要对其在空间辐射环境下的性能变化规律进行研究。基于色心模型,从理论上分析了电离辐射对光纤布拉格光栅传输性能的影响。采用^(60)Co-γ辐射源对两根布拉格中心波长分别为825 nm和835 nm的掺锗单模光纤布拉格光栅进行了总剂量为1.01×10~6rad的电离辐射实验。实验结果表明,随着辐照剂量的增加,光纤布拉格光栅反射谱的峰值波长发生了红移现象,光栅的折射率增加。经过总剂量1.01×10~6rad辐照后,布拉格中心波长825 nm和835 nm的峰值波长分别增加了0.070 62 nm和0.074 15 nm。实验结果与色心模型推导出的光栅有效折射率与辐射剂量的函数关系式相符合;为光纤布拉格光栅在空间环境温度及应变测量的运用提供数据基础。

Damage and recovery of fiber Bragg grating under radiation environment

To develop the application of fiber Bragg gratings as temperature and strain sensors in space environments, it is necessary to understand the effect of high-energy radiation on the performance of the fiber Bragg grating. We performed an experiment involving Co（60）-γ ionizing irradiation with a total dose of 1.01 × 10~6 rad on two Ge-doped single-mode fiber Bragg gratings with central wavelengths of 825 and 835 nm, respectively. We found that, with the increase of radiation dose, the redshift of the peak wavelength of the reflection spectrum of the fiber Bragg gratings indicated the increase of the refractive index and the number of color centers. After irradiation, the refractive index decreased with the decreasing number of color centers. We analyzed the influence of ionizing irradiation on the transmission performance of the fiber Bragg gratings using a color-center model, which explained the experimental results. The proposed model was used to determine the creation rate and annihilation rates of the color center, which are foundational data for using the fiber Bragg gratings in space applications.

小管R134a两相流压降噪音与流型关系

两相流型的非可视化图形判断有着其应用需求。目前的方法有电容法和压降法,均在实验室研究阶段。本文以R134a为工质,研究了2 mm管径下泵驱回路两相流压降噪音与流型的关系。用高速摄像仪观察和记录石英玻璃管中两相流流型、用单片机采样系统对回路测量段进行压降高密度采样(1 kHz)。对各流型下的压降数据作快速傅里叶变换得到其压降频谱图,分析了压降噪音来源,并据此在特定条件下对流型进行初步区分。研究表明,波状流、间歇流、环状流在压降低频噪音及压降直流分量上表现出不同的特性,就给出相关的无量纲参数区分流型的可行性进行了讨论,为非可视化的两相流型在线判断提供了依据。但两相流型区分的普适性判据仍有待深入研究。

深度、温度与高度:历史纪录片《战国大学堂之稷下学宫》的破圈传播路径

大型历史文化纪录片《战国大学堂之稷下学宫》聚焦中国历史上的文化丰碑—稷下学宫,立足全球视野,探寻齐鲁文化、儒家文化乃至华夏文明的思想源头与发展道路。该片致力于在跨文化传播语境下实现创新出圈,以人物、地理、时空等多个视角展开历史叙事,通过写实与写意相结合的影像表达形式,深耕中华优秀传统文化的当代价值,兼具内容深度、表达温度和思想高度。