基于双DSP的智能有源无功补偿器

针对现存的混合型有源滤波器的无源滤波部分只是对1种谐波情况设计的、对变化的信号不能改变滤波形式、当电网波动时增加有源滤波部分的压力等问题,进行了改进。其创新点是引入可控可调式的补偿电路结构,可以针对变化的电网情况改变补偿的网络结构,而不是仅仅改变同一网络的参数,对电网达到跟踪补偿的效果。它对电网谐波污染和无功损耗均有很好的抑制和补偿作用,必定会在实际应用中得到广泛的发展。     

一种厚铜刚挠结合印制板渗胶改善

厚铜刚挠结合板的生产中一般采用普通流胶半固化片制作,在满足厚铜填胶的同时也导致窗口渗胶的问题越发突出,严重影响弯折性能,本研究选取一款应用于电源模块的105μm厚铜刚挠结合板,结合半固化片类型、压合参数、保护胶带类型、窗口设计等,极大程度的克服了窗口渗胶问题.     

冷切焦水一体化处理技术在惠炼延迟焦化装置的应用

文章简要介绍了国内延迟焦化装置冷切焦水的分流处理工艺。惠炼延迟焦化采用冷切焦水一体化处理技术,投资小、操作方便、处理效果好,从操作管理与技改两方面对减轻冷切焦水的挥发烃污染提出了改进措施。     

基于曲线拟合的轮胎PRAT计算方法分析

轮胎PRAT(Plysteer Residual Aligning Torque)的值一般较小,计算PRAT所需轮胎力学特性的测试精度要求较高,对测试数据的不同处理方法也会得到不同的PRAT值。本文介绍了三种测试数据的曲线拟合方法,通过分析得出三次多项式曲线拟合法可以更方便地得到较精确的PRAT值。     

改进的EEMD算法及其在多相流检测中的应用

针对低信噪比下EEMD法在分解过程中产生模态混叠导致滤波效果变差的问题,提出了一种改进的EEMD滤波方法.该方法首先设计最优带通滤波器,滤除信号中的脉冲干扰,再将滤波后的信号进行EEMD分解,然后采用SG滤波器对筛选的IMF再进行滤波,最后对滤波后IMF进行重构.最后将改进的EEMD法和EEMD法分别用于多相流测量信号滤波及含水率测量,结果表明,改进的EEMD法与EEMD法相比,信噪比提高了约2～3 dB,滤波效果更好;含水率平均测量精度提高了约3％,测量误差更小.     

基于光纤光栅应变传感系统的在役港口起重机结构健康监测

港口起重机工作环境恶劣、使用频繁,且服役周期长,其金属结构随着服役时间的增长必然会出现不同程度的损伤。为了掌握在役港口起重机运行时的健康状态,研究了基于光纤光栅应变传感系统的在役港口起重机健康监测。采用具有温度补偿功能的反射式光纤光栅传感系统对港口起重机几种典型工况(变幅、旋转、吊重和卸载完整过程等)进行了实时在线监测。现场实测结果验证了该方法的可行性并突出了港口起重机结构状态检测的必要性,现场实测结果也为港口起重机的在线安全诊断和预测提供了数据支撑。     

一种时域电磁法剩余油探测装置的参数研究

提出了一种非接触式剩余油探测装置的参数设计方法.通过两种观测装置在均匀介质中时域电磁响应特性的对比,确定了最佳观测装置结构.分析了发射信号脉冲宽度和关断时间对响应信号的影响.研究了发射线圈电性与实际发射波形关断时间的关系,提出了发射线圈参数的选择原则.讨论了斜阶跃波激励下接收线圈的过渡过程,并给出了匹配电阻和接收线圈分布电容的估算方法.根据分析结果最终设计了装置参数并进行了室内实验.结果表明,不论从响应信号幅度还是延迟时间,均可对不同电导率的介质进行有效识别,为今后时间域电磁法剩余油探测的井下实验奠定了基础.     

单次快前沿电脉冲信号的远距离低抖动传输

本文介绍了一种低时间间隔抖动的单次快前沿脉冲序列信号的远距传输技术.该技术采用远距离传输高重频信号来产生单次触发信号,利用该技术在距信号源端100 m处获得了时间间隔抖动峰峰值小于100 ps的单次脉冲信号.该技术对我国新一代高功率固体激光驱动器以及其它需要高精度同步的仪器或者设备的设计具有较高的参考价值.     

Discovery of a Short‐Chain Dehydrogenase from Catharanthus roseus that Produces a New Monoterpene Indole Alkaloid

Plant monoterpene indole alkaloids, a large class of natural products, derive from the biosynthetic intermediate strictosidine aglycone. Strictosidine aglycone, which can exist as a variety of isomers, can be reduced to form numerous different structures. We have discovered a short‐chain alcohol dehydrogenase (SDR) from plant producers of monoterpene indole alkaloids (Catharanthus roseus and Rauvolfia serpentina) that reduce strictosidine aglycone and produce an alkaloid that does not correspond to any previously reported compound. Here we report the structural characterization of this product, which we have named vitrosamine, as well as the crystal structure of the SDR. This discovery highlights the structural versatility of the strictosidine aglycone biosynthetic intermediate and expands the range of enzymatic reactions that SDRs can catalyse. This discovery further highlights how a sequence‐based gene mining discovery approach in plants can reveal cryptic chemistry that would not be uncovered by classical natural product chemistry approaches.     

Preparation of solid acid catalyst packing AAO/SBA-15-SO3H and application for dehydration of xylose to furfural

The solid acid catalyst packing AAO/SBA-15-SO₃H was prepared by the co-condensation and grafting method with porous anodic aluminum oxide (AAO) as support. FT-IR, SEM and TEM were applied to characterize the prepared samples. Results showed that catalysts prepared by two methods both contained active centers, and SBA-15 nanorod arrays grow inside a porous alumina membrane AAO and are perpendicular to the substrate. Their catalytic performances were tested for dehydration of xylose to furfural. The conversion of xylose and selectivity of furfural were 90% and 74% on the AAO/SBA-15-SO₃H(C) catalyst prepared by the co-condensation method, respectively. The deactivation and regeneration of the AAO/SBA-15-SO₃H(C) catalyst for the dehydration of xylose were also investigated, the activity of catalyst treated by 30 wt.% H₂O₂ almost was recovered.