基于破坏与重建学习的植物病虫害细粒度分类方法

目前,我国对植物病虫害的分类主要依靠人工分类的方法,造成了人力浪费、资源利用率低等问题.属于同一类别的植物叶片通常具有极其相似的颜色、形状等外观特征,常规分类方法难以区分.为提高分类速度与准确率,提出一种改进破坏与重建学习方法的病虫害检测器.针对模型参数量大的问题,引入RepVGG轻量化网络替换ResNet50作为主干...     

一种新颖的单相PWM整流器控制器

PWM（Pulse Width Modulation）整流器具有输入功率因数可调,四象限运行等特点,是具有较好应用前景的一款电力电子装置。在分析了单相PWM整流器四象限换流工作方式的基础上,从提高功率因数和提高装置的响应速度两个方面进行考虑,设计了单相PWM整流器的控制器。由于传统的滞环电流控制存在开关频率不固定,对开关器件的频率要求较高,且增加开关损耗,本设计采用定频滞环电流控制;在控制策略的选择中,同时也考虑了单相PWM整流器直流侧电压二次谐波的影响,为了不影响响应速度,本设计并没有在直流侧采用LC滤波器或陷波器,而是采用二次谐波电压补偿的方法。仿真实验结果进一步验证了所设计的控制器不仅提高了装置的功率因数,同时也加快了其响应速度。     

Effect of Al content on the electrochemical properties of Mg2−xAlxNi thin film hydride electrodes

Thin films of Mg_2−xAl_xNi alloys have been prepared by magnetron sputtering, and the effects of partial substitution of Al for Mg on the electrochemical properties of the films were studied. EIS results indicate the rate-limiting process for the thin film hydride electrode is the charge transfer reaction during the process of total discharge. A theoretical model has been derived for the impedance of a thin film hydride electrode based upon the assumption that hydrogen diffusion is neglected in the electrode. The charge-transfer reaction rate at the electrode surface and hydrogen diffusivity in the Mg_2−xAl_xNi thin film hydride electrodes were observed to initially decrease then increase with increasing Al content. Results from capacitance measurements indicate n-type semiconductor properties for the corrosion layer during the charge–discharge process. Hydrogen atom and OH⁻ transfer became more difficult with increasing Al content until x = 0.3, after which a significant drop in the barrier resistance was observed.     

基于ATM E1的变电站远程视频监控信号中断故障排除

随着无人值班变电站的全面推广,变电站远程视频监控系统,是保证变电站安全运行必不可少的重要手段,而变电站视频监控信号中断,将使变电站失去所有的安全（火警、防窃等等）监控,文章从变电站视频监控的概念、系统构成、网段设置以及故障判断等方面作了深刻的阐述,最好通过故障处理的例子来说明信号中断故障的处理方法。     

Ultraprecision surface finishing of nano-ZrO2 ceramics using two-dimensional ultrasonic assisted grinding

Based on the model of a grain cutting trace in workpiece during two-dimensional ultrasonic assisted grinding, microscopic cutting trace of the grain is analyzed, and the grain cutting trace of spiral line is defined, the motion model of the contact between single abrasive particle and workpiece in a vibration period is established during two-dimensional ultrasonic assisted grinding, and the results show that the grain motion mode of two-dimensional ultrasonic assisted grinding is similar to the rotary cutting mode. Grinding experiments on surface quality of nano-ZrO₂ ceramic are carried out using diamond grinding in different condition, both with and without ultrasonic vibration. Experimental results show that the surface quality after two-dimensional ultrasonic assisted grinding is superior to that after diamond grinding, and it is easier for two-dimensional ultrasonic assisted grinding as material removal mechanism employs ductile grinding mode.     

板坯边裂原因分析与控制

热轧板卷边裂是常见的质量缺陷。介绍了邯钢2250热轧生产线板坯边裂的形貌特征及分布规律。分析了边裂产生的原因主要是夹渣和夹杂造成的。通过建立和完善《热轧板卷边裂图谱》,有针对性地指导炼钢生产,边裂缺陷率由3.0%以上减少到0.4%以下,降级改判损失明显减少。     

声波吹灰技术在广州珠江电厂4号炉的应用

在燃煤锅炉中广泛使用的蒸汽吹灰器存在故障率高、维护成本高、管壁磨损重、局部吹不到等缺点,而声波吹灰器的利用可以有效解决上述问题。广州珠江电厂4号炉通过在锅炉尾部烟道增加声波吹灰器,并实现DCS集散控制,取得良好效果。     

浅谈固体废物的危害及管理

炼化企业是高污染高能耗企业,在正常生产过程中会产生一定数量的固体废物,了解其性质及危害,采取"减量化-资源化-无害化"的处置流程,能减少固体废物的产生量.通过分析我国工业固体废物的现状和应用.及其对大气、水、土壤、健康环境的影响,克拉玛依石化公司推行ISO14001环境管理体系,加强固体废物管理,建设合理的固体废物处置设施,提出炼化企业应该使固体废物从产生到处置,最终实现固体废物的无害化.     

小麦实仓储藏过程中杂质对微生物活动及储藏品质的影响

在小麦实仓储藏过程中,依据小麦入仓时不同落点、杂质含量及分布,将整仓小麦划分为非杂质区和杂质区,在两区域中进行定点定时取样,并检测所取样品的各类杂质含量、外部霉菌量及储藏品质指标,结果表明:在杂质区,当筛下物、麦皮和麦秸含量较高时,粮堆水分较高;筛下物、麦皮、麦秸等有机杂质携带的微生物较多,对小麦籽粒表面的霉菌量影响较大,而无机杂质则影响较小;杂质区的小麦储藏品质变化较快,随着储藏时间的延长,杂质区与非杂质区的脂肪酸值、过氧化物酶活性、发芽率存在显著性差异.     

水淬机架的有限元分析及优化研究

水淬机架是钢管热处理生产线上十分重要的部件,以往主要靠经验和类比同型机器进行设计,设计的反复性大,周期长,可靠性差.本文介绍了机架的基本结构和原设计的不足之处.讨论了如何运用有限元分析软件ANSYS对机架进行强度、刚度和模态分析; 研究了机架的无阻尼自由振动,得到了系统的固有频率和振型,利用优化设计技术对机架进行优化设计,为提高新产品研发质量和效率提供了一种有效的途径.