开关电源RE102仿真与实测

采用AltiumDesigner16设计并制备了某降压开关电源PCB样品。根据GJB151B-2013中的RE102测试要求,使用CST线缆、微波和设计工作室建立开关电源PCB及RE102测试环境的电磁仿真模型,探讨开关电源PCB的RE102仿真方法,仿真并实测开关电源PCB与线缆的辐射结果。开关电源PCB的RE102仿真与实测结果高度吻合,仿真方法正确。     

ZL102合金热压缩变形力学性能和微观组织的研究

研究了不同压缩比对ZL102合金的显微组织及性能的影响．实验结果表明：ZL102在铸态结构组织下,其机械性能较差,但是在经过热压缩加工以后其抗拉强度有了不同程度的提高,并且和其变形量有着直接的关系,其中压缩比为85．81oA时抗拉强度增加幅度最大;ZL102经过热压缩以后,其塑性没有明显的改善;金相组织观察表明,随着变形量的增加,晶粒细化程度增大．     

Revisiting Cytochrome P450‐Mediated Oxyfunctionalization of Linear and Cyclic Alkanes

Cytochrome P450 monooxygenases (CYPs) of the CYP153 family catalyse terminal hydroxylation of n‐alkanes. Alkane hydroxylating mutants of self‐sufficient CYP102A1 have also been described. We evaluated two CYP153s (a three‐component system and a fused self‐sufficient CYP), wild‐type CYP102A1 and nine CYP102A1 mutants, for the conversion of three cycloalkanes (C₆, C₇ and C₈) and three n‐alkanes (C₆, C₈ and C₁₀) using whole cells (WCs) and crude cell‐free extracts (CFEs). The aim was to identify substrate–enzyme combinations that give high product titres and space‐time yields (STYs). Comparisons were made using total turnover numbers (TTNs) and turnover frequencies (TOFs) to normalize for CYP expression. Reactions were carried out using high enzyme and substrate concentrations compatible with high STYs. Under these conditions CYP102A1 and the double R47L,Y51F mutant, although not regioselective, performed better on all substrates in terms of product titres over 8 h, and thus STYs and TTNs, than heavily mutated variants that have been reported to give very high TOFs. CYP153A6, with its ferredoxin (Fdx) and ferredoxin reductase (FdR), emerged as the superior catalyst for conversion of n‐alkanes. In addition to its excellent regioselectivity it also gave the highest final product titres and STYs in WC conversions of hexane and octane. Interaction with FdR and Fdx initially limited performance in CFEs, but with additional FdR and Fdx gave 1‐octanol titres of 50 mmol⋅L_BRM⁻¹ and TTNs exceeding 12,000 over 18 h, rivalling results reported with self‐sufficient CYPs. Selecting biocatalysts for application requires caution, since experimental conditions such as amount of substrate added and solubility as well as cofactor dependence and regeneration can have a profound effect on catalyst performance, while stability and efficiency with regard to cofactor usage (coupling efficiency) are at least as important as TOFs when high product titres and STYs are the target.

     

星载大容量固态存储器EMI辐射测试与分析

基于星载大容量固态存储器的EMI辐射测试结果,对其电磁不兼容状态进行了EMC分析与整改。依据GJB151A-1997,星载大容量固态存储器需要满足RE102电场辐射要求,为了使RE102超标严重的星载大容量固态存储器满足标准要求,首先,结合星载大容量固态存储器的工作原理,依据电磁屏蔽理论及电磁辐射理论,对RE102的测试结果进行了分析。其次,确定了辐射超标的主要原因为互连线缆的电磁辐射,并进一步分析了电磁辐射的激励源产生方式。最后,依据分析结果提出了相应的整改方案并进行了整改。结果表明,采用EMC屏蔽和滤波措施后,EMI发射衰减大于30dB,星载大容量固态存储器的EMI辐射测试结果满足RE102技术指标要求。     

基于TSM102的高效率铅酸蓄电池充电器设计

针对当前市场上流行的铅酸蓄电池充电器充电效率过低,开关器件消耗的热功率过大,投入在散热装置上的成本过高,充电器体积太大等多种弊端,提出一种新型的低成本、高效率铅酸蓄电池充电器设计方案。     

高精度无线同步技术研究与实现

介绍了基于nRF24L01和rfw102两种无线芯片的无线同步技术,分析了它们各自的优缺点。重点介绍基于rfw102的无线同步技术,其中基于rfw02频压转换方式实现的同步技术、同步延时短,同步精度高,整个同步过程不超过5us。     

基于TH102芯片的电源电路

采用TH102设计的超低功耗开关电源不仅须对输入／输出进行隔离，而且差模干扰和共模干扰要低。反激式开关变压器和反馈控制回路设计，以及考虑电磁兼容性对电路改进是其关键技术。其中，反激式开关变压器设计包括计算初级电感量、设计变压器变比、减小变压器漏感、设计反激式变压器工作方式等。     

基于优化CBAM改进YOLOv5的农作物病虫害识别

针对多种农作物病虫害图像, 在自然环境下因虫害种类繁多, 小目标特征相似的技术问题, 导致检测困难难以达到令人满意的精度. 本文提出了一种自然背景下加强局部特征和全局特征信息融合的害虫检测识别模型YOLOv5-EB, 在公开的大规模害虫数据集IP102上进行实验, 结果表明该研究比YOLOv5模型精确度提高了5个百分点. 引入一维卷积替换CBAM中通道注意力的MLP操作, 优化了通道注意力经过全局处理后容易忽略通道内信息交互的问题; 其次使用6×6卷积替换Focus操作, 来增强提取害虫特征的能力. 实验结果表明, 对害虫进行检测时, YOLOv5-EB的平均精度值达到了87%, 与Faster R-CNN、EfficientDet、YOLOv3、YOLOv4、YOLOv5模型相比, 不仅有效提高了作物害虫图像的识别性能, 而且有效提高了检测速度. 研究表明, YOLOv5-EB算法满足对多种农作物病虫害目标检测的准确性和实时性要求.     

IEC 60870-5-102标准在实际应用中的探讨

IEC60870-5-102标准是电能累计量传输的国际标准 ,但在国内电能量采集系统中 ,厂商之间直接以其为标准的互连一直存在障碍。通过对电能数据需求和运行特点的总结 ,分析造成这一现象的原因。在介绍了目前对标准的处理与改进办法后 ,一方面说明其取得的成绩 ,另一方面继续探讨现阶段应用中仍旧存在的条件限制