搜索结果: 1-15 共查到“知识库 工学 Low-Frequency”相关记录17条 . 查询时间(0.625 秒)
ANOMALY IDENTIFICATION FROM SUPER-LOW FREQUENCY ELECTROMAGNETIC DATA FOR THE COALBED METHANE DETECTION
Electromagnetic Super Low Frequency Coalbed Methane non-Gaussian Class B model Least Square Gradient Adaptive filter
2016/11/30
Natural source Super Low Frequency(SLF) electromagnetic prospecting methods have become an increasingly promising way in the resource detection. The capacity estimation of the reservoirs is of great i...
COMPENSATION LOW-FREQUENCY ERRORS IN TH-1 SATELLITE
Satellite photogrammetry Low-frequency errors Attitude determination system Exterior orientation elements Location accuracy Global coverage
2016/7/4
The topographic mapping products at 1:50,000 scale can be realized using satellite photogrammetry without ground control points (GCPs), which requires the high accuracy of exterior orientation element...
LOW FREQUENCY ERROR ANALYSIS AND CALIBRATION FOR HIGH-RESOLUTION OPTICAL SATELLITE’S UNCONTROLLED GEOMETRIC POSITIONING
high-resolution optical satellite low frequency error star sensor uncontrolled geometric positioning
2016/7/4
The low frequency error is a key factor which has affected uncontrolled geometry processing accuracy of the high-resolution optical image. To guarantee the geometric quality of imagery, this paper pre...
PASSIVE ULTRA-LOW FREQUENCY ELECTROMAGNETIC DETECTION TECHNOLOGY FOR COAL BED METHANE AND ITS APPLICATION
Ultra-Low Frequency Electromagnetic Wave CBM Exploration Geophysical Method
2015/12/29
Based on analysis of the significance of the coal bed methane exploration and development and the deficiency of the conventional coal bed methane exploration methods, the paper proposes a new technolo...
Extremely low frequency plasma turbulence recorded by the DEMETER satellite in the ionosphere over the Abruzzi region prior to the April 6, 2009, L’Aquila earthquake
ionosphere turbulence earthquake
2015/8/24
The present study analyzes the low frequency fluctuations of the magnetic and electric fields prior to the earthquake with magnitude M.6.3 on April 6, 2009, in the Abruzzi region in Italy. This includ...
Application of empirical mode decomposition to very low frequency signals for identification of seismic-ionospheric precursor phenomena
Earthquake Precursor Phenomena Empirical Mode Decomposition
2015/8/24
This study investigates the application of empirical mode decomposition to signals from very low frequency transmitters in Europe that were received in Thessaloniki, Greece, to provide a method for de...
2D阀控电液激振器低频段振动波形分析（Low Frequency Excited Waveforms Analysis of an Electro-hydraulic Vibration Exciter Using a 2D Valve）
控制阀 电液激振器 低频段 振动波形
2010/12/29
2D阀控电液激振器是利用2D阀阀芯的匀速旋转和轴向滑动改变阀口面积变化波形，以产生频率和幅值可独立调节的振动波形。在分析该激振器工作原理的基础上，建立数学模型，采用分段积分的方法，推导出激振器输出波形方程的解析解，最后，将实验得到的波形与解析波形进行对比，根据频谱特性分析波形的失真度。研究结果表明：在低频段，由于主要受到弹性负载力方向变化的影响，振动波形表现出上升与下降过程的不对称，其不对称度取决...
低频振荡研究现状与展望（Status quo and Perspective of Low-Frequency Oscillation Research）
低频振荡 机理 分析方法 抑制措施
2010/8/17
低频振荡现象是目前电力系统研究关注的热点之一。文章从机理解释、分析方法和抑制措施三方面综述了近年来该领域取得的突破与进展，并指出应对一些用弱阻尼机理无法解释的振荡现象，特别是“超低频振荡”现象给予足够的重视。
IPSO Based UPFC Robust Output Feedback Controllers for Damping of Low Frequency Oscillations
UPFC IPSO output feedback Controller
2010/2/2
On the basis of the linearized Phillips-Herffron model
of a single-machine power system, a novel method for designing
unified power flow controller (UPFC) based output feedback
controller is presen...
Solvent Extraction of Bitumen from Jordan Oil Shale Assisted by Low Frequency Ultrasound
Jordanian oil shale Low frequency ultrasound Solvent extraction Ultrasonically assisted extraction Bitumen
2010/9/8
In this work, the efficiency of 20 kHz frequency ultrasounds versus the classical stirring procedure was investigated on the solvent extraction of Jordanian El-Lajjun oil shale by employing a horn typ...
南方电网低频振荡问题及PSS参数分析（Analysis on Low Frequency Oscillation and PSS Parameters in China Southern Power Grid）
南方电网 小干扰稳定 电力系统稳定器 特征值灵敏度
2010/8/17
采用SSAP电力系统小干扰稳定分析软件，对南方电网2010年典型运行方式下的区间低频振荡模式进行了详细的分析。通过在适当机组加装PSS，并根据灵敏度提供的信息对PSS参数进行优化调整后，系统稳定性得以显著提高。
Low Frequency Ambient Noise Measurement in Sagami Bay
Low Frequency Ambient Noise Measurement Sagami Bay
2009/8/19
For the purpose of monitoring deep seafloor environmental changes associated with a submarine earthquake swarm, a cabled observatory consisting of multidisciplinary sensors including a hydrophone was ...
Low-Frequency NMR of Laser-Polarized Xenon on a Liquid Surface
High-power laser-diode Polarized xenon Surface NMR
2009/6/10
We have optically polarized the nuclear spin of xenon atoms using a frequency-narrowed high-power laser-diode. The free-induction signals of polarized xenon in gas and liquid phases were measured in a...
Calibration and Use of the UGA EASY Evaporation Pan for Low Frequency Sprinkler Irrigation of Cotton in a Clay Soil
Cotton Calibration
2008/6/11
A new irrigation scheduling tool called the UGA EASY Pan (Evaporation-based Accumulator for Sprinkler-enhanced Yield) allows remote observation of evaporation that can be correlated with crop water us...
Low Frequency Noise of Tantalum Capacitors
Tantalum capacitors Noise in Tantalum capacitors
2010/12/7
A low frequency noise and charge carriers transport mechanism analysis was performed on tantalum capacitors in order to characterise their quality and reliability. The model of Ta−Ta2O5−Mn...