人为排放对信阳市细颗粒物和臭氧的影响评估

基于信阳市2017—2020年细颗粒物(PM_2.5)和臭氧(O₃)浓度数据及同期地面气象观测资料,利用Kolmogorov-Zurbenko(KZ)滤波法将原始浓度序列分解为短期分量、季节分量和长期分量,采用逐步回归方法建立污染物基线分量和短期分量与相应尺度气象要素的线性回归模型,通过对残差进行滤波和序列重建,得到去除气象影响的污染物长期变化趋势,该浓度仅与污染物的排放量有关。结果表明,PM_2.5和O₃浓度的波动主要由污染源排放及气象条件的短期变化和季节变化引起,气象条件对PM_2.5季节分量和O₃长期分量影响较大。信阳市PM_2.5污染排放减弱,O₃污染排放先升高,在2018年10月后降低。由于污染排放导致的2017—2020年PM_2.5和O₃长期分量分别降低3.5、1.5μg/(m³·a)。     

浅论光通信传输技术在专业领域的应用

文章介绍了光通信的起源与特点,重点介绍了光纤通信技术,阐明了光纤技术发展的重要里程。根据光纤通信技术的特点,着重论述了光通信传输技术在石油工业中的应用。     

浅析宁夏回族自治区财政支农支出现状

财政支农支出是政府为了扶持和促进农业经济发展,改善农村的生活条件,提高农民的生活水平,实现城乡之间协调、稳定、可持续发展,将财政用于支持农业和农村发展的建设性资金支付给农业领域而形成的支出。本文介绍了宁夏回族自治区的财政支农支出规模、财政支农支出结构以及现行财政支农政策和方式的局限性。     

A polarization mismatched p-GaN/p-Al0.25Ga0.75N/p-GaN structure to improve the hole injection for GaN based micro-LED with secondary etched mesa

A low hole injection efficiency for InGaN/GaN micro-light-emitting diodes (μLEDs) has become one of the main bottlenecks affecting the improvement of the external quantum efficiency (EQE) and the optical power. In this work, we propose and fabricate a polarization mismatched p-GaN/p-Al$_{0.25}$Ga$_{0.75}$N/p-GaN structure for 445 nm GaN-based μLEDs with the size of $40 \times 40 $μm$^{2}$, which serves as the hole injection layer. The polarization-induced electric field in the p-GaN/p-Al$_{0.25}$Ga$_{0.75}$N/p-GaN structure provides holes with more energy and can facilitate the non-equilibrium holes to transport into the active region for radiative recombination. Meanwhile, a secondary etched mesa for μLEDs is also designed, which can effectively keep the holes apart from the defected region of the mesa sidewalls, and the surface nonradiative recombination can be suppressed. Therefore, the proposed μLED with the secondary etched mesa and the p-GaN/p-Al$_{0.25}$Ga$_{0.75}$N/p-GaN structure has the enhanced EQE and the improved optical power density when compared with the μLED without such designs.