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Study on Component Synthesis Active Vibration Suppression Method Using Zero-placement Technique 被引量:4
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作者 张建英 刘暾 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第4期304-312,共9页
The component synthesis active vibration suppression method (CSVS) can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according... The component synthesis active vibration suppression method (CSVS) can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach. 展开更多
关键词 flexible structure vibration suppression component synthesis active vibration suppression method zero-placement technique
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Recent progresses in the suppression method based on the growth mechanism of lithium dendrite 被引量:9
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作者 Xiaolong Xu Suijun Wang +4 位作者 Hao Wang Chen Hu Yi Jin Jingbing Liu Hui Yan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2018年第2期513-527,共15页
Lithium secondary batteries(LSBs) with high energy densities need to be further developed for future applications in portable electronic devices, electric vehicles, hybrid electric vehicles and smart grids. Lithium ... Lithium secondary batteries(LSBs) with high energy densities need to be further developed for future applications in portable electronic devices, electric vehicles, hybrid electric vehicles and smart grids. Lithium metal is the most promising electrode for next-generation rechargeable batteries. However, the formation of lithium dendrite on the anode surface leads to serious safety concerns and low coulombic efficiency.Recently, researchers have made great efforts and significant progresses to solve these problems. Here we review the growth mechanism and suppression method of lithium dendrite for LSBs’ anode protection. We also establish the relationship between the growth mechanism and suppression method. The research direction for building better LSBs is given by comparing the advantages and disadvantages of these methods based on the growth mechanism. 展开更多
关键词 Lithium dendrite Growth mechanism suppression method Lithium secondary battery
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Multiple Suppression Using T-A Dual Polynomial Fitting Method 被引量:1
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作者 王辉 崔若飞 《International Journal of Mining Science and Technology》 SCIE EI 1999年第1期55-59,共5页
Principles of polynomial fitting zero offset profile are introduced, and a new polynomial fitting method, tbe time-amplitude dual fitting method, is developed. The method can be used to purify seismic waves and suppre... Principles of polynomial fitting zero offset profile are introduced, and a new polynomial fitting method, tbe time-amplitude dual fitting method, is developed. The method can be used to purify seismic waves and suppress multiples. The effect of suppressing multiples is compared with other multiple suppression methods. 展开更多
关键词 DUAL FITTING method ZERO OFFSET PROFILE multiple suppression
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Research on Vibration Suppression of the Finite Plate with Square Steel Beams Using Traveling Wave Method 被引量:1
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作者 焦映厚 侯守武 +2 位作者 刘春川 陈照波 李明章 《Journal of Donghua University(English Edition)》 EI CAS 2012年第4期283-287,共5页
The vibration suppression of the finite plate with square steel beams is studied using traveling wave method. The finite plate with square beams is modeled as the coupling systems between the plate flexural motion and... The vibration suppression of the finite plate with square steel beams is studied using traveling wave method. The finite plate with square beams is modeled as the coupling systems between the plate flexural motion and the flexural and torsional motions for the square beams. The vibration response at any position of the coupling structure can be obtained by wave method. Numerical results show that comparing to finite element method (FEM), not only the low frequency but also the medium-high frequency vibration response of the finite plate with square beam can be effectively calculated by wave method. The suppression effect can be increased as the square beam is located at one-third of the length of plate or increasing the height of the beam. The study provides reference for arranged square beams applying to vibration suppression of ship and train structures. 展开更多
关键词 finite plate traveling wave method square steel beam vibration suppression
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Research on Suppression Method of Warhead Infrared Image Background Based on Small Area Filtering
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作者 Yehui Li Shaohua Sun 《Journal of Computer and Communications》 2018年第11期155-161,共7页
In order to reduce the computational complexity of searching in massive information in detecting of warhead targets, background removal is usually the first step of target detection algorithm in sequential frame image... In order to reduce the computational complexity of searching in massive information in detecting of warhead targets, background removal is usually the first step of target detection algorithm in sequential frame images. In this paper, an adaptive multi-exposure time preserving star edge small area filtering background removal algorithm is proposed, which can suppress the back-ground and preserve the target and star edges. This algorithm not only ensures the accuracy of centroid and orbit determination, but also reduces false alarm and improves tracking accuracy. 展开更多
关键词 WARHEAD INFRARED Image suppression method
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Vibration harmonic suppression technology for electromagnetic vibrators based on an improved sensorless feedback control method
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作者 Wei LI Junning CUI +1 位作者 Xingyuan BIAN Limin ZOU 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2024年第3期472-483,共12页
To realize low harmonic distortion of the vibration waveform output from electromagnetic vibrators,we propose a vibration harmonic suppression technology based on an improved sensorless feedback control method.Without... To realize low harmonic distortion of the vibration waveform output from electromagnetic vibrators,we propose a vibration harmonic suppression technology based on an improved sensorless feedback control method.Without changing the original driving circuit,the alternating current(AC)equivalent resistance of the driving coil is used to obtain high-precision vibration velocity information,and then a simple and reliable velocity feedback control system is established.Through the study of the effect of different values of key parameters on the system,we have achieved an effective expansion of the velocity characteristic frequency band of low-frequency vibration,resulting in an enhanced harmonic suppression capability of velocity feedback control.We present extensive experiments to prove the effectiveness of the proposed method and make comparisons with conventional control methods.In the frequency range of 0.01-1.00 Hz,without using any sensors,the method proposed in this study can reduce the harmonic distortion of the vibration waveform by about 40%compared to open-loop control and by about 20%compared to a conventional sensorless feedback control method. 展开更多
关键词 Vibration calibration Electromagnetic vibrators Harmonic suppression Sensorless control method Velocity feedback control
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Numerical simulations of sloshing and suppressing sloshing using the optimization technology method 被引量:2
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作者 Hui GUAN Yifei XUE +1 位作者 Zhiiun WEI Chuijie WU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2018年第6期845-854,共10页
Sloshing is a common phenomenon in nature and industry, and it is important in many fields, such as marine engineering and aerospace engineering. To reduce the sloshing load on the side walls, the topology optimizatio... Sloshing is a common phenomenon in nature and industry, and it is important in many fields, such as marine engineering and aerospace engineering. To reduce the sloshing load on the side walls, the topology optimization and optimal control methods are used to design the shape of the board, which is fixed in the middle of the tank. The results show that the new board shape, which is designed via topology optimization, can significantly reduce the sloshing load on the side wall. 展开更多
关键词 SLOSHING volume of fluid (VOF) method suppressing sloshing topologyoptimization
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Optimal Valve Closure Operations for Pressure Suppression in Fluid Transport Pipelines
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作者 Tehuan Chen Zhigang Ren 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第4期1010-1018,共9页
When a valve is suddenly closed in fluid transport pipelines,a pressure surge or shock is created along the pipeline due to the momentum change.This phenomenon,called hydraulic shock,can cause major damage to the pipe... When a valve is suddenly closed in fluid transport pipelines,a pressure surge or shock is created along the pipeline due to the momentum change.This phenomenon,called hydraulic shock,can cause major damage to the pipelines.In this paper,we introduce a hyperbolic partial differential equation(PDE)system to describe the fluid flow in the pipeline and propose an optimal boundary control problem for pressure suppression during the valve closure.The boundary control in this system is related to the valve actuation located at the pipeline terminus through a valve closing model.To solve this optimal boundary control problem,we use the method of lines and orthogonal collocation to obtain a spatial-temporal discretization model based on the original pipeline transmission PDE system.Then,the optimal boundary control problem is reduced to a nonlinear programming(NLP)problem that can be solved using nonlinear optimization techniques such as sequential quadratic programming(SQP).Finally,we conclude the paper with simulation results demonstrating that the full parameterization(FP)method eliminates pressure shock effectively and costs less computation time compared with the control vector parameterization(CVP)method. 展开更多
关键词 Hydraulic shock HYPERBOLIC PDE system method of lines optimal boundary control orthogonal COLLOCATION method PRESSURE suppression
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Suppress numerical dispersion in reversetime migration of acoustic wave equation using optimal nearly analytic discrete method
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作者 Liu Ming-Zhu He Bing-Shoug 《Applied Geophysics》 SCIE CSCD 2020年第1期133-142,170,共11页
Using staggered-grid finite difference method to solve seismic wave equation,large spatial grid and high dominant frequency of source cause numerical dispersion,staggeredgrid finite difference method,which can reduce ... Using staggered-grid finite difference method to solve seismic wave equation,large spatial grid and high dominant frequency of source cause numerical dispersion,staggeredgrid finite difference method,which can reduce the step spatial size and increase the order of difference,will multiply the calculation amount and reduce the efficiency of solving wave equation.The optimal nearly analytic discrete(ONAD)method can accurately solve the wave equation by using the combination of displacement and gradient of spatial nodes to approach the spatial partial derivative under rough grid and high-frequency condition.In this study,the ONAD method is introduced into the field of reverse-time migration(RTM)for performing forward-and reverse-time extrapolation of a two-dimensional acoustic equation,and the RTM based on ONAD method is realized via normalized cross-correlation imaging condition,effectively suppressed the numerical dispersion and improved the imaging accuracy.Using ONAD method to image the groove model and SEG/EAGE salt dome model by RTM,and comparing with the migration sections obtained by staggered-grid finite difference method with the same time order 2 nd and space order 4 th,results show that the RTM based on ONAD method can effectively suppress numerical dispersion caused by the high frequency components in source and shot records,and archive accurate imaging of complex geological structures especially the fine structure,and the migration sections of the measured data show that ONAD method has practical application value. 展开更多
关键词 Acoustic wave equation RTM ONAD method numerical dispersion suppression
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风电场集电线路单相接地故障柔性电压消弧与动态保护新原理
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作者 喻锟 杨理斌 +3 位作者 曾祥君 王沾 李理 卓超 《中国电机工程学报》 EI CSCD 北大核心 2024年第5期1789-1801,I0010,共14页
为解决风电场集电系统长期存在的线路单相接地故障处理难题,提出风电场中性点柔性接地方式,理论推导获得柔性接地风电场三序等效电路,与集电线路单相接地故障复合序网模型,建立风电场零序电压柔性调控理论,提出集电线路单相接地故障柔... 为解决风电场集电系统长期存在的线路单相接地故障处理难题,提出风电场中性点柔性接地方式,理论推导获得柔性接地风电场三序等效电路,与集电线路单相接地故障复合序网模型,建立风电场零序电压柔性调控理论,提出集电线路单相接地故障柔性电压消弧方法,可主动将故障点电压及故障残流迅速抑制到零,实现单相接地故障电弧的可靠消除。进一步提出基于零序电流动态增量的高阻故障辨识与保护方法,通过柔性调控零序补偿电流,逐渐放大故障残流,实现永久性单相接地故障的灵敏感知与保护。利用PSCAD/EMTDC搭建含双馈异步风电机(doubly-fedinduction generator,DFIG)的规模化风电场模型,模拟多种运行与故障条件对所提方法进行验证,仿真结果表明,该方法能够在考虑系统不平衡电压的情况下精准调控集电线路故障点电压,实现瞬时性单相接地故障快速可靠消弧,动态感知并持续抑制永久性单相接地故障残流,实现集电线路高阻接地故障的灵敏保护。该技术有望提升风电场运行灵活性与故障防御能力,有力保障新能源电能外送的持续性、可靠性。 展开更多
关键词 集电线路 柔性接地 单相接地故障 电压消弧 动态保护
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抑烟沥青复掺配比优化及抑烟效果评价
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作者 李萍 陈修乐 +3 位作者 张强 念腾飞 王育兴 王盟 《化工进展》 EI CAS CSCD 北大核心 2024年第4期1923-1933,共11页
为抑制沥青在高温下烟气的产生,降低环境污染及对作业人员健康的影响程度,本文进行了抑烟沥青复掺配比优化研究。基于单掺抑烟沥青的针入度、延度及软化点及自制沥青烟生成富集装置的沥青产烟结果,结合熵权法与遗传算法进行抑烟沥青复... 为抑制沥青在高温下烟气的产生,降低环境污染及对作业人员健康的影响程度,本文进行了抑烟沥青复掺配比优化研究。基于单掺抑烟沥青的针入度、延度及软化点及自制沥青烟生成富集装置的沥青产烟结果,结合熵权法与遗传算法进行抑烟沥青复掺配比优化,并分析优化复掺抑烟剂在沥青中的分散均匀性、储存稳定性及其对沥青特征官能团的影响;基于优化复掺配比的抑烟沥青高、中、低温性能测试,并对其抑烟效果进行评价,验证优化复掺配比方法的有效性。研究表明:抑烟剂均匀分散于沥青中,且未对沥青特征官能团产生改变,优化复掺抑烟沥青满足储存稳定性要求。优化复掺抑烟剂对沥青高、低温性能具有改善作用,并提升了沥青中温抗疲劳性能。沥青烟收集前后滤管颜色变化表明该沥青烟富集方式具有较高的可靠性,且优化复掺抑烟沥青具有显著抑烟效果,最大抑烟率为99.7%。优化复掺配比下的指标预测值与实测值差异较小,证明了该优化复掺配比方法的可靠性。 展开更多
关键词 抑烟沥青 熵权法 遗传算法 抑烟效果
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粉末外摩擦系数试验研究进展
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作者 钟文镇 杨潮 +3 位作者 柴银福 石欣琳 赵庆鑫 陈超 《粉末冶金技术》 CAS CSCD 北大核心 2024年第4期437-450,共14页
粉末与界面的外摩擦行为受粉末的材料性能、模壁表面粗糙度、相对运动速度、温度和压力等因素的影响,不合理的外摩擦行为很容易造成粉末加工装备的磨损以及制品密度分布不均匀。为探究粉末的外摩擦行为,深入考察了国内外粉末外摩擦系数... 粉末与界面的外摩擦行为受粉末的材料性能、模壁表面粗糙度、相对运动速度、温度和压力等因素的影响,不合理的外摩擦行为很容易造成粉末加工装备的磨损以及制品密度分布不均匀。为探究粉末的外摩擦行为,深入考察了国内外粉末外摩擦系数的研究进展,归纳和总结了粉末外摩擦系数的测试方法。根据载荷不同,将粉末外摩擦系数测试方法分为小载荷测试方法和大载荷测试方法,其中,小载荷外摩擦系数测试方法包括斜面法和平板法,大载荷外摩擦系数测试方法包括旋转法、剪切法和闭模法。遵循以上分类方法,进一步阐述了各种测试方法的原理、测试设备以及获取的重要结论。结果表明,小载荷作用下的测试方法仅适用于测量低相对密度粉末的外摩擦系数,测试中的压制力一般低于粉末重量的100倍。大载荷作用下的测试方法更常用于高相对密度粉末的外摩擦系数测量,测试中的压制力因材料而异,聚合物材料的压制力通常在粉末重量的0.5×10^(3)~1.0×10^(5)倍,金属材料的压制力在粉末重量的10^(5)~10^(7)倍。 展开更多
关键词 粉末 外摩擦系数 测试方法 压制 研究进展
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基于相对拟牛顿法的自卫式欺骗干扰抑制算法
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作者 齐美彬 赵谦 +3 位作者 徐晋 项厚宏 杨艳芳 崔国龙 《现代雷达》 CSCD 北大核心 2024年第1期66-73,共8页
自卫式欺骗干扰与目标信号高度相似,且二者的到达角完全相同,传统的主瓣干扰抑制算法难以对其进行抑制。针对该问题,文中在极化单输入多输出(PSIMO)雷达系统下,提出一种基于相对拟牛顿法的盲源分离算法。该算法利用干扰和目标的极化特... 自卫式欺骗干扰与目标信号高度相似,且二者的到达角完全相同,传统的主瓣干扰抑制算法难以对其进行抑制。针对该问题,文中在极化单输入多输出(PSIMO)雷达系统下,提出一种基于相对拟牛顿法的盲源分离算法。该算法利用干扰和目标的极化特性差异,通过构建重叠子阵结构计算出联合自相关矩阵,并采用相对拟牛顿法估计出分离矩阵,从而将目标和干扰信号分离在不同的通道上,实现干扰抑制作用。仿真实验结果表明,该算法能够有效抑制自卫式欺骗干扰,且在低信噪比(SNR)和密集干扰场景下依然具有良好的干扰抑制性能,当输入SNR为-10 dB时,输出的目标检测概率仍可以达到51.6%,拥有较强的鲁棒性。 展开更多
关键词 主瓣干扰抑制 自卫式欺骗干扰 极化差异 相对拟牛顿法 重叠子阵结构
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基于偏转角抑制的改进人工势场法路径规划
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作者 金涛 于莲芝 《电子科技》 2024年第10期15-22,29,共9页
针对传统人工势场法在实际应用中存在的局部最极小值、目标不可达以及路径震荡等问题,文种提出了一种基于偏转角抑制的改进人工势场法。该方法以传统人工势场法为基础,采用改进斥力势场函数保证目标点为全局势能最低点。在路径解算中引... 针对传统人工势场法在实际应用中存在的局部最极小值、目标不可达以及路径震荡等问题,文种提出了一种基于偏转角抑制的改进人工势场法。该方法以传统人工势场法为基础,采用改进斥力势场函数保证目标点为全局势能最低点。在路径解算中引入偏转角抑制因子来抑制无人车行驶过程中过大的偏转角,在无人车陷入局部极小值点后每一步的路径解算中都添加新的虚拟目标点,直至无人车累积一定的偏转角摆脱障碍物群。仿真实验结果表明,该算法可以在不影响无人车避障的情况下减少规划路径的震荡性,并能够使无人车逃脱复杂障碍物群顺利到达目标点,规划出一条有效、简短以及震荡较少的路径。 展开更多
关键词 人工势场法 路径规划 无人车 震荡过滤 偏转角抑制 虚拟目标点 局部极小值 避障
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二硫化钼 还原氧化石墨烯对涤纶织物的阻燃性能 被引量:1
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作者 李伟 韩宾宾 +1 位作者 薛阳彪 郑敏 《现代纺织技术》 北大核心 2024年第2期130-140,共11页
为了赋予涤纶(PET)织物良好的阻燃、抑烟性能,实现PET织物的低烟、无卤阻燃,采用浸轧工艺,用水热法制备二硫化钼还原氧化石墨烯(MoS_(2)/RGO)复合材料,并将其用于PET织物的阻燃整理。采用扫描电子显微镜、红外光谱仪以及X射线衍射仪等对... 为了赋予涤纶(PET)织物良好的阻燃、抑烟性能,实现PET织物的低烟、无卤阻燃,采用浸轧工艺,用水热法制备二硫化钼还原氧化石墨烯(MoS_(2)/RGO)复合材料,并将其用于PET织物的阻燃整理。采用扫描电子显微镜、红外光谱仪以及X射线衍射仪等对MoS_(2)/RGO复合材料以及MoS_(2)/RGO/PET织物的微观形貌与化学结构进行分析;采用垂直燃烧测试仪、烟雾密度箱、接触角仪等对MoS_(2)/RGO/PET织物的阻燃、抑烟性能以及亲水性能进行表征与测试。结果表明:MoS_(2)/RGO复合材料在织物上能够形成良好包覆,且能够有效提高PET织物的热稳定性,在700℃时,其残炭率较纯织物明显提升;MoS_(2)/RGO/PET织物的极限氧指数可提升至28.2%,总热释放量较纯PET织物下降60.5%,烟雾密度降低59.9%,具有良好的自熄性能,损毁长度可降低至10.6 cm。此外,MoS_(2)/RGO复合材料可以赋予PET织物良好的亲水性能,在2.2 s时接触角变为0°,有效改善了PET织物的服用舒适性能。 展开更多
关键词 二硫化钼还原氧化石墨烯(MoS_(2)/RGO) 阻燃整理 抑烟 PET织物 水热法 浸轧
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秸秆基新型道路抑尘剂的制备与应用
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作者 方宏萍 秦语漩 +3 位作者 竹涛 李桂贤 马连刚 谢天航 《化工环保》 CAS CSCD 北大核心 2024年第3期417-426,共10页
以玉米秸秆为主要原料,以复合酶(木聚糖酶、β-葡聚糖酶、纤维素酶与羧甲基纤维素钠(CMC))、淀粉、Na_(2)CO_(3)为辅料,制备了一种道路抑尘剂,采用响应面分析法优化了制备工艺,并考察了该抑尘剂对大气中PM_(2.5)和PM_(10)的去除效果。... 以玉米秸秆为主要原料,以复合酶(木聚糖酶、β-葡聚糖酶、纤维素酶与羧甲基纤维素钠(CMC))、淀粉、Na_(2)CO_(3)为辅料,制备了一种道路抑尘剂,采用响应面分析法优化了制备工艺,并考察了该抑尘剂对大气中PM_(2.5)和PM_(10)的去除效果。实验结果表明:4种酶对抑尘剂失水率的影响顺序为β-葡聚糖酶>木聚糖酶>CMC>纤维素酶;在木聚糖酶、β-葡聚糖酶、纤维素酶与CMC质量比2.5∶1∶15∶23.5、反应温度45℃、反应pH 4.75、淀粉与复合酶质量比1.8∶1的最佳条件下,所制得抑尘剂的黏度为48 mPa·s、表面张力为0.02 N/m、密度为1028 kg/m^(3)、失水率为2.17%;喷洒该抑尘剂后,大气中PM_(2.5)的质量浓度从75.74~114.83 mg/m^(3)降低至0.34~0.91 mg/m^(3),PM_(10)的质量浓度从49.94~74.57 mg/m^(3)降低至0.12~0.34 mg/m^(3),去除率均大于99%。 展开更多
关键词 抑尘剂 道路扬尘 秸秆 响应面分析法
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碲镉汞红外探测器前置放大电路低温稳定性研究
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作者 韩俊丽 刘福浩 +3 位作者 杨晓阳 马丁 余双洋 李向阳 《半导体光电》 CAS 北大核心 2024年第4期653-657,共5页
在航天工程应用过程中,发现室温下HgCdTe红外探测器前置放大电路输出正常,但是当温度降低至-55℃时,输出有振荡现象,对探测器施加红外辐照后振荡现象加剧。文章首次对该现象进行系统研究,提出了HgCdTe红外探测器电路在低温下光照后的等... 在航天工程应用过程中,发现室温下HgCdTe红外探测器前置放大电路输出正常,但是当温度降低至-55℃时,输出有振荡现象,对探测器施加红外辐照后振荡现象加剧。文章首次对该现象进行系统研究,提出了HgCdTe红外探测器电路在低温下光照后的等效电路模型,从相位裕度与增益裕度角度分析前置放大电路在低温下产生振荡的机理,并在此基础上,提出了抑制低温光照后前置放大电路振荡的解决方法,实验结果验证了该方法的有效性。 展开更多
关键词 等效模型 电路低温光致振荡现象 产生机制 抑制方法
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输电线路短路电流对埋地管道电位抬升及抑制方法研究
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作者 段绍辉 宗伟 +3 位作者 周灵杰 阮江军 黄道春 陈辉荣 《电测与仪表》 北大核心 2024年第3期89-94,共6页
针对城市中输电线路与埋地油气金属管道临近问题,通过建立架空导/地线-杆塔-接地网-埋地管道一体化电磁场计算模型,综合考虑导线和避雷线对金属管道的感性耦合影响以及杆塔入地电流对管道的阻性耦合影响。基于此模型研究土壤电阻率、临... 针对城市中输电线路与埋地油气金属管道临近问题,通过建立架空导/地线-杆塔-接地网-埋地管道一体化电磁场计算模型,综合考虑导线和避雷线对金属管道的感性耦合影响以及杆塔入地电流对管道的阻性耦合影响。基于此模型研究土壤电阻率、临近距离、管道参数、交叉跨越角度以及不同供流方式对金属管道电位、防腐层耐受电压的影响规律,并开展管道电位抬升的抑制方法研究,可以为输电线路发生接地短路故障时临近燃油(气)管道安全防护提供指导。 展开更多
关键词 输电线路 埋地金属管道 电位抬升 抑制方法
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航空过滤器压力脉动衰减抑制机理分析
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作者 赵龙超 张遨翔 +2 位作者 姚静 杨帅 张乾瑞 《液压与气动》 北大核心 2024年第1期141-149,共9页
应急放能源系统是飞机液压系统失效时用于飞机起落架收放的应急动力单元,但该系统存在压力脉动大导致系统不稳定等问题,严重影响飞机的运行安全。利用航空过滤器内部腔体形成压力脉动衰减器对脉动进行抑制。采用压力波声学传播理论及Com... 应急放能源系统是飞机液压系统失效时用于飞机起落架收放的应急动力单元,但该系统存在压力脉动大导致系统不稳定等问题,严重影响飞机的运行安全。利用航空过滤器内部腔体形成压力脉动衰减器对脉动进行抑制。采用压力波声学传播理论及Comsol Multiphysics进行了有限元建模及仿真,得到过滤器腔体直径、腔体长度、入口直径、出口直径为影响过滤器传递损失的关键参数。通过实验测试,过滤器后压力脉动幅值由20.9±0.44 MPa衰减至20.9±0.15 MPa,衰减效果良好,增大腔体直径后脉动抑制效果进一步增强,与仿真结果一致。验证了过滤器压力脉动建模仿真方法的正确性,也为小流量液压系统过滤器设计提供了新的思路。 展开更多
关键词 过滤器 压力脉动 有限元法 Comsol 脉动抑制
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局域共振弹性超材料梁禁带宽度的拓宽方法
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作者 王岗 万少可 +3 位作者 洪军 李乐乐 刘硕 李小虎 《西安交通大学学报》 EI CAS CSCD 北大核心 2024年第10期63-71,共9页
针对传统局域共振弹性超材料存在禁带宽度窄的问题,引入非均匀分布振子设计方法,在不改变振子总质量的前提下实现了禁带拓宽。首先,采用谱元法(SEM)建立通用弹性超材料梁模型,对单、双层均匀振子超材料梁结构的振动传递特性进行分析;然... 针对传统局域共振弹性超材料存在禁带宽度窄的问题,引入非均匀分布振子设计方法,在不改变振子总质量的前提下实现了禁带拓宽。首先,采用谱元法(SEM)建立通用弹性超材料梁模型,对单、双层均匀振子超材料梁结构的振动传递特性进行分析;然后,保持振子总质量相等,提出单、双层非均匀振子超材料梁的设计策略;最后,搭建实验装置对所提结构的振动抑制性能进行测试。研究结果表明:振子间的特征频率差异越大,最终形成的禁带宽度越宽,但禁带范围内的频响曲线会大幅波动,此时可通过加入适当阻尼进行抑制,使禁带曲线变得平稳;对于双振子超材料梁,振子的质量比和阻尼均会对结构的禁带特性产生影响,在振子与梁质量相同的条件下,单层非均匀及均匀振子超材料梁可分别形成带宽为440、68 Hz的禁带,双层非均匀及均匀振子超材料梁可分别形成带宽为395、40 Hz的禁带。研究表明所提超材料结构能够有效实现振动抑制,可为周期结构的振动问题提供一种新的调控方法。 展开更多
关键词 弹性超材料 局域共振 谱元法 振动抑制 非均匀振子
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