精密红外辐射计测量模块研究北大核心CSCD

红外辐射计用于红外热像仪测试设备的校准。介绍了一种用于红外辐射计的测量模块及方法。设计了采样保持的测量方案,通过参考信号生成采样脉冲,并将采样点设置在每个信号周期的1/4相位处,能显著提高微弱信号的测量能力。对于35℃的黑体辐射信号,通过与现有方案的对比实验,测量信号强度可提高57.6%;在红外热像仪测试设备背景温度为22℃条件下,通过与现有仪器的对比测试,测量信号精度可提升50%以上。     

Oscillator strength study of the excitations of valence-shell of C2H2 by high-resolution inelastic x-ray scattering

The oscillator strengths of the valence-shell excitations of C₂H₂ are extremely important for testing theoretical models and studying interstellar gases. In this study, the high-resolution inelastic x-ray scattering (IXS) method is adopted to determine the generalized oscillator strengths (GOSs) of the valence-shell excitations of C₂H₂ at a photon energy of 10 keV. The GOSs are extrapolated to their zero limit to obtain the corresponding optical oscillator strengths (OOSs). Through taking a completely different experimental method of the IXS, the present results offer the high energy limit for electron collision to satisfy the first Born approximation (FBA) and cross-check the previous experimental and theoretical results independently. The comparisons indicate that an electron collision energy of 1500 eV is not enough for C₂H₂ to satisfy the FBA for the large squared momentum transfer, and the line saturation effect limits the accuracy of the OOSs measured by the photoabsorption method.     

新型吡啶-杯[4]芳烃荧光探针的合成及其对Fe3+的检测性能

合成了一种新型的高选择性检测Fe3+的上沿功能化吡啶-杯[4]芳烃荧光探针,其结构经1H NMR, 13C NMR和HR-MS表征。离子检测实验结果表明,该吡啶-杯[4]芳烃探针的最大吸收峰出现在295 nm处,并在371 nm处显示出一个强的荧光发射带。与其他金属离子相比,新型探针对Fe3+表现出高选择性和强抗干扰能力的荧光淬灭响应。通过荧光滴定法和Job曲线图研究了探针与Fe3+的结合性。结果表明,探针与Fe3+形成2:1的配合物,缔合常数为3.26×107 M-1,检出限为7.9×10-7 M。     

先进绝热压缩空气储能系统的设计计算

作为一种重要的可再生能源,风能的不稳定性问题亟待解决。压缩空气储能(CAES)系统是解决该问题的一种有效途径。先进绝热压缩空气储能(AA-CAES)系统在传统CAES系统的基础上得到改进,在环境保护、资源节约上有明显的优势。以1.5 MW的AA-CAES为例,介绍了先进绝热压缩空气储能系统的设计过程,并给定具体参数进行计算,对该系统的特性及应用前景进行了分析总结。     

5MW大型风力机气动特性计算及分析

分别采用BEM和CFD方法对NREL 5 MW风力机的气动特性进行计算,通过分析不同风速下各气动参数的变化规律,揭示了大型变速变桨风力机的功率特性和载荷特性。两种计算结果的详细对比和分析表明,高风速时由于雷诺数大幅增加,BEM方法计算的功率和载荷偏大,在采用BEM方法进行大型风力机的气动设计和校核时,应当考虑雷诺数的影响。同时,失速延迟修正和叶尖损失修正模型在高风速时有较大误差,有必要深入验证传统的修正模型在大型风力机上的适用性。     

MW级地面燃气轮机热力循环分析

本文以俄罗斯GTDl250型燃气轮机为样本对MW级地面燃气轮机进行了热力循环分析.MW级地面燃气轮机作为一类小型(轻型)、多转子(双转子)、具有简单或复杂循环的燃气轮机,在电力工业、石油工业和战车动力等方面有着广泛的用途.在热力循环分析的基础上,提出了我国在研制高性能MW级地面燃气轮机时应重点解决的问题.     

Flat Top Optical Frequency Combs Based on a Single-Core Quantum Cascade Laser at Wavelength of ～8.7 μm

We present optical frequency combs with a spectral emission of 48 cm^-1and an output power of 420 m W based on a single-core quantum cascade laser at λ ～ 8.7μm. A flat top spectrum sustains up to 130 comb modes delivering ～ 3.2 m W of optical power per mode, making it a valuable tool for dual comb spectroscopy. The homogeneous gain medium, relying on a slightly diagonal bound-to-continuum structure, promises to provide a broad and stable gain for comb operating. Remarkably, the dispers...     

Automatic measurement device of laser-induced damage threshold and its experiment北大核心

A set of 1 064 nm and 532 nm automatic measurement device of laser-induced damage threshold (LIDT) of dual-wavelength optical elements was designed and constructed for automatic detection of LIDT of optical elements film. The device was mainly composed of pulsed laser light source, beam parameter diagnosis component, damage online diagnosis component, scanning motion platform for parts to be tested and control system. The whole measuring device and measurement process were automatically controlled by the computer integrated measuring software based on Labview, which could realize the automatic measurement of damage threshold in the range of energy density from 0.1 J/cm2～100 J/cm2, and the device was also used to measure the 1 064 nm antireflection film and aluminum reflection film samples. The results show that the damage thresholds are 27.09 J/cm2 and 3.21 J/cm2, with a relative uncertainty of 3.91% and 5.61%, respectively. © 2023 Editorial office of Journal of Applied Optics. All rights reserved.