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Application of wavelet scalogram in feature extraction of acoustic emission signal
Xiao Siwen,Liao Chuanjun,Li Xuejun
Strategic Study of CAE 2008, Volume 10, Issue 11, Pages 69-75
Acoustic emission (AE) signals initiated by mechanical faults or damages is composed of two types of signals: high frequency burst impulse signal and long period quasi-stationary noise signal. Wavelet scalogram has a particular time-frequency localization, which helps it to be well used for describing the time-frequency characteristics of AE signals. By analyzing the characteristics and feature extraction of typical AE signals, the paper applies wavelet scalogram for fault diagnosis based on AE technique, and presents the wavelet scalogram analysis method of AE signal for the first time. By theoretical analysis and simulation, the wavelet basis function and parameter related to the function are defined. So the limitation that best time resolution and frequency resolution of wavelet scalogram cannot get at the same time is overcome effectively. When applying wavelet scalogram for fault diagnosis of rolling bearings based on AE techniques, the results are quite visualized, clear and accurate. Both simulations and experimental research prove that wavelet scalogram can be used for condition monitoring and fault diagnosis based on AE detection well.
Keywords： wavelets scalogram acoustic emission feature extraction fault diagnosis rolling bearing
Velocity-Free MS/AE Source Location Method for Three-Dimensional Hole-Containing Structures Article
Longjun Dong, Qingchun Hu, Xiaojie Tong, Youfang Liu
Engineering 2020, Volume 6, Issue 7, Pages 827-834 doi: 10.1016/j.eng.2019.12.016
Microseismic source/acoustic emission (MS/AE) localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures. However, the locating errors induced by both the irregular structure and pre-measured velocity are poorly understood in existing methods. To meet the high-accuracy locating requirements in complex three-dimensional hole-containing structures, a velocity-free MS/AE source location method is developed in this paper. It avoids manual repetitive training by using equidistant grid points to search the path, which introduces A* search algorithm and uses grid points to accommodate complex structures with irregular holes. It also takes advantage of the velocity-free source location method. To verify the validity of the proposed method, lead-breaking tests were performed on a cubic concrete test specimen with a size of 10 cm × 10 cm × 10 cm. It was cut out into a cylindrical empty space with a size of ϕ6cm × 10 cm. Based on the arrivals, the classical Geiger method and the proposed method are used to locate lead-breaking sources. Results show that the locating error of the proposed method is 1.20 cm, which is less than 2.02 cm of the Geiger method. Hence, the proposed method can effectively locate sources in the complex three-dimensional structure with holes and achieve higher precision requirements.
Looking Back and Prospecting to the Project Design ofthe Spaceflight Launching Site in China
Zhang Zeming
Strategic Study of CAE 2007, Volume 9, Issue 4, Pages 1-5
This paper introduces the development history of the project design of spaceflight launching site in China and the main forms used in the design, and points out that there shouldn't exist only one fixed mode for the spacecraft launch. China should, according to its national condition, design and build the launching project facility and device that correspond to the technology development of spacecraft and carrier rocket.
Keywords： launching site project design development history integrated mode
Opinion on Space Launch and Manned Lunar-landing
Zhang Zeming ,Jiang Yi ,Fu Debin
Strategic Study of CAE 2006, Volume 8, Issue 10, Pages 37-41
The lunar-landing is the continuation of manned spaceflight engineering. Comparing with the manned airship engineering, it requires more credibility and sweepingness, and it needs more funds. On the basis of China´s achievements and foreign countries´ experiences, the paper brings forward the idea of using the existing transportation technology to sent the launch vehicles and cosmonauts to the near-earth orbit in batches, assembling the components together on the space-launch platform, and then launching them to the moon. The paper also discusses the space-launch platform and the launching way.
Keywords： lunar-landing space launch launch platform lunar-landing orbit technical route
Launch dynamics of multibody system and its applications
Rui Xiaoting
Strategic Study of CAE 2011, Volume 13, Issue 10, Pages 76-82
Bad firing precision, huge consumption of projectiles in test and launch unsafety are the three difficult technology problems constraining the development of modern rockets and gun weapons. Firing precision and the launch safety of weapon system depend on dynamics style of weapon system. As a engineering subject of multidisciplinary approach studying the motion styles of weapon system and the force acting on it during launch process, launch dynamics has been a new technological breakthrough in improving firing precision and launch safety of rockets and gun weapon system in the world, provided new theory and technology for design and test of firing precision and launch safety. In this paper, theory and technology of launch dynamics of multibody system and its applications in design and test of firing precision and safety for rockets and gun weapons are studied.
Keywords： firing precision consumption of projectile in test launch safety launch dynamics of multibody system transfer matrix method of multibody system
The general planning scenarios of electromagnetic rail launch system
Zhai Lipeng, Feng Junwen, Wang Huating, Bai Ju
Strategic Study of CAE 2008, Volume 10, Issue 8, Pages 45-50
In the analysis of the electromagnetic rail launch system.,this paper discusses the general developmental strategy of electromagnetic rail launch system based on the scenario planning theory. Through analyzing the world current situation and the key technical variables of electromagnetic orbit launch system, the paper conceives the three developmental strategy models of future electromagnetic rail launch system and proposes the focus of development strategy.
Keywords： electromagnetic rail launch system scenario planning development strategy
With Great Expectations, Webb Telescope Finally Lifts Off
Mitch Leslie
Engineering 2022, Volume 11, Issue 4, Pages 3-5 doi: 10.1016/j.eng.2022.02.002
Wang Anquan,Cheng Xiaofang,Lu Shaosong
Strategic Study of CAE 2002, Volume 4, Issue 8, Pages 54-57
The principle of primary-color method for temperature measurement is firstly introduced in this article. Based on the lineal model of spectral emissivity in the range of visible spectrum, the formulation of radiative chrominance of real bodies is put forward. Afterwards, it's made clear that two temperature solutions can be derived from one specific chrominance at most. The radiative color gamut is determined and divided into two components, the single-solution gamut and the dual-solution gamut.
Keywords： temperature measurement primary-color method color gamut emissivity
Long March 3 Series Launch Vehicle
Long Lehao
Strategic Study of CAE 1999, Volume 1, Issue 1, Pages 11-18
The background, design approach, system engineering, launch results and technical & development characteristics of LM - 3 series launch vehicles are presented, and the development of launch vehicles in the future is prospected. It is indicated that with advanced performance, these launch vehicles are the main force of commercial heavy lift in China.
Keywords： aerospace heavy lift launch vehicle launch services LM - 3 series launch vehicle
Clinical response with functional image during radiotherapy of esophageal squamous cell carcinoma
Yu Jinming
Strategic Study of CAE 2012, Volume 14, Issue 7, Pages 9-19
18F-FLT uptake can be used to monitor the biological response of esophageal SCC and normal tissue to RT. Increased uptake of 18F-FLT following treatment interruptions may reflect accelerated repopulation. 18F-FLT PET may have advantages compared to 18F-FDG PET in differentiating inflammation from tumor. 18F-FLT PET may help oncologists predict treatment response as early as one week after the beginning of treatment and estimate clonogenic repopulation during RT. 18F-FETNIM PET can depict hypoxia in esophageal SCC. Prior to CCRT, tumor hypoxia demonstrates spatial variability in different days, though overall 18F-FETNIM uptake remains similar. Baseline SUVmax may be predictive of treatment response.
Keywords： esophageal carcinoma radiotherapy positron emission tomography accelerated repopulation hypoxia
An investigation of local high spatial resolution adaptive PET system
Liu Jingjing,Xie Qingguo
Strategic Study of CAE 2011, Volume 13, Issue 10, Pages 105-112
A critical challenge in positron emission tomography (PET) is to develop affordable systems having high spatial resolution. We imagine a PET system, for imaging a region of interest (ROI) with ultra high performances and other regions with normal performances by use of inhomogeneous performances PET detectors. We propose such a prototype, consisting of a few ultra high intrinsic spatial resolution PET detectors and quite a few normal ones. In this paper, we investigate the effect of the location and the number of high resolution detectors. The high resolution detectors are grouped in a continuous partial ring. The initial results show that such a prototype is capable to bring the advantages of significantly improving the spatial resolution in a ROI. For a specified area, the improvement is influenced by the location and fraction of high resolution detectors in a ring. The encouraging results also indicate the possibilities to regulate detectors to achieve high spatial resolution according to the application, which is possibly formulated.
Keywords： positron emission tomography adaptive PET system region of interest local spatial resolution inhomogeneous performance PET detector
The Influence of Priori Knowledge on Soil Moisture Inversion by Using Passive Remote Sensing
Tang Lu,Li Zongqian,Shi Changsheng,Wang Xin
Strategic Study of CAE 2005, Volume 7, Issue 3, Pages 53-58
It's pointed out by this paper that the priori knowledge of random rough soil surface is needed in soil moisture inversion by using passive remote sensing, so the precision of priori knowledge has effect on the inversion result. Several kinds of inversion error are defined in this paper to depict the influence of three kinds of priori knowledge on the inversion, these three kinds of priori knowledge are the type of soil surface height distribution, soil temperature, and soil texture. Simulation result shows that it's feasible to invert soil moisture by neural network (NN) based on bi-spectrum model (BSM) . Using two kinds of emissivity data of two polarizations as the input of NN, the inversion error of soil moisture is allowable even there is some uncertainty on these three kinds of priori knowledge.
Keywords： microwave remote sensing priori knowledge emissivity soil moisture bi-spectrum model neural network
Thermal/vacuum calibration of microwave humidity sounder on FY-3B satellite
Wang Zhenzhan,Zhang Shengwei,Li Jing,Li Yun,Wu Qiong
Strategic Study of CAE 2013, Volume 15, Issue 10, Pages 33-46
The principle and methods on thermal/vacuum (T/V) testing of microwave humidity sounder (MWHS) on FY-3B satellite were described; correction algorithms on calibration errors were developed, and some main specifications of MWHS-3B, such as linearity, sensitivity and calibration precision, were obtained. The parameters derived from the T/V testing had been used in in-orbit data processing to produce brightness temperature products in FY-3B ground system.
Keywords： FY-3B satellite microwave humidity sounder prelaunch calibration thermal/vacuum testing
Xun Li, Baoyan Duan, Yiqun Zhang, Yongxin Guo
Engineering 2023, Volume 30, Issue 11, Pages 63-74 doi: 10.1016/j.eng.2023.07.016
This work presents an optimal design method of antenna aperture illumination for microwave power transmission with an annular collection area. The objective is to maximize the ratio of the power radiated on the annular collection area to the total transmitted power. By formulating the aperture amplitude distribution through a summation of a special set of series, the optimal design problem can be reduced to
finding the maximum ratio of two real quadratic forms. Based on the theory of matrices, the solution to the formulated optimization problem is to determine the largest characteristic value and its associated characteristic vector. To meet security requirements, the peak radiation levels outside the receiving area are considered to be extra constraints. A hybrid grey wolf optimizer and Nelder–Mead simplex method is developed to deal with this constrained optimization problem. In order to demonstrate the effectiveness of the proposed method, numerical experiments on continuous apertures are conducted; then, discrete arrays of isotropic elements are employed to validate the correctness of the optimized results. Finally, patch arrays are adopted to further verify the validity of the proposed method.
Keywords： Microwave power transmission Beam collection efficiency Ring-shaped beam Annular collection area Grey wolf optimizer Nelder–Mead simplex method
Experimental study on BPA uptake of glioma cell lines
Yang Lei,Wang Xiao,Sui Li,Kong Fuquan,Hao Xiaojuan,Zheng Jieying,Ma Nanru,Cui Suzhen,Liu Quanwei,Zhao Kui
Strategic Study of CAE 2012, Volume 14, Issue 8, Pages 85-90
Objective: to evaluate the incorporation of BPA by glioma cell lines, and to observe its relationship with the temperature and the concentration of BPA. Methods: C6, U251 and rat astrocyte cells were incubated in a culture medium, in which 10B concentration was 20, 40, 60, 80, 100 μg/mL for 24 h. Boron concentration in the cells was measured induced couple plasma-atomic emission spectroscopy (ICP-AES). C6 cells were pre-incubated for 24 h with different boron concentrations in growth medium. Then the mediums were changed to boron-free ones, and boron content was assessed after 1, 2, 3 h. Results: The content of the 10B in cells was increasing with the increasing concentration of BPA, and the boron concentration ratios of glioma cells to astrocyte are 2.2. The BPA efflux is slower at the lower temperature. Conclusion: BPA has a selectivity for glioma cells, and the results of the efflux assay confirm the temperature dependence of the BPA transport out of the cells.
Keywords： boron neutron capture therapy BPA glioma cell line ICP AES
Title Author Date Type Operation
Application of wavelet scalogram in feature extraction of acoustic emission signal
Xiao Siwen,Liao Chuanjun,Li Xuejun
Journal Article
Velocity-Free MS/AE Source Location Method for Three-Dimensional Hole-Containing Structures
Longjun Dong, Qingchun Hu, Xiaojie Tong, Youfang Liu
Journal Article
Looking Back and Prospecting to the Project Design ofthe Spaceflight Launching Site in China
Zhang Zeming
Journal Article
The general planning scenarios of electromagnetic rail launch system
Zhai Lipeng, Feng Junwen, Wang Huating, Bai Ju
Journal Article
Determination and Division of Radiative Color Gamut in Primary-Color Method for Temperature Measurement
Wang Anquan,Cheng Xiaofang,Lu Shaosong
Journal Article
Clinical response with functional image during radiotherapy of esophageal squamous cell carcinoma
Yu Jinming
Journal Article
An investigation of local high spatial resolution adaptive PET system
Liu Jingjing,Xie Qingguo
Journal Article
The Influence of Priori Knowledge on Soil Moisture Inversion by Using Passive Remote Sensing
Tang Lu,Li Zongqian,Shi Changsheng,Wang Xin
Journal Article
Thermal/vacuum calibration of microwave humidity sounder on FY-3B satellite
Wang Zhenzhan,Zhang Shengwei,Li Jing,Li Yun,Wu Qiong
Journal Article
Optimal Design of Aperture Illuminations for Microwave Power Transmission with Annular Collection Areas
Xun Li, Baoyan Duan, Yiqun Zhang, Yongxin Guo
Journal Article
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