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提高连铸坯质量的关键技术

上海金属 2025年第1期47卷 1-10页

作者：吴杰陈文杰宝山钢铁股份有限公司上海201999

由于工艺参数及外部条件的变化,连铸坯极易产生元素偏析、粗大碳化物、中心缩孔等缺陷,提高均质化程度是确保连铸坯质量的关键。目前,电磁搅拌技术、末端压下技术和脉冲磁致振荡技术是提高连铸坯均质化程度的主要技术措施。

关键词：连铸坯电磁搅拌末端压下脉冲磁致振荡均质化

Unsupervised robust adaptive filtering against impulsive noise

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Journal of Systems Engineering and Electronics 2012年第1期23卷 32-39页

作者： Tao Ma Jie chen wenjie chen Zhihong Peng School of Automation Beijing Institute of Technology Beijing 100081 R R. China Key Laboratory of Complex System Intelligent Control and Decision （Ministry of Education） Beijing Institute of Technology Beijing 100081 P. R. China

An implementation of adaptive filtering, composed of an unsupervised adaptive filter （UAF）, a multi-step forward linear predictor （FLP）, and an unsupervised multi-step adaptive predictor （UMAP）, is built for suppressing impulsive noise in unknown circumstances. This filtering scheme, called unsupervised robust adaptive filter （URAF）, possesses a switching structure, which ensures the robustness against impulsive noise. The FLP is used to detect the possible impulsive noise added to the signal, if the signal is ＂impulse-free＂, the filter UAF can estimate the clean sig- nal. If there exists impulsive noise, the impulse corrupted samples are replaced by predicted ones from the FLP, and then the UMAP estimates the clean signal. Both the simulation and experimental results show that the URAF has a better rate of convergence than the most recent universal filter, and is effective to restrict large disturbance like impulsive noise when the universal filter fails.

关键词： adaptive filtering unsupervised form impulse insen- sitive switching structure.

Urban Stormwater Modeling with Local Inertial Approximation Form of Shallow Water Equations: A Comparative Study

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International Journal of Disaster Risk Science 2021年第5期12卷 745-763页

作者： Weiqi Wang wenjie chen Guoru Huang School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510640China State Key Laboratory of Subtropical Building Science School of Civil Engineering and TransportationSouth China University of TechnologyGuangzhou 510640China Guangdong Engineering Technology Research Center of Safety and Greenization for Water Conservancy Project Guangzhou 510640China

This study focused on the performance and limitations of the local inertial approximation form model(LIM)of the shallow water equations(SWEs)when applied in urban flood modeling.A numerical scheme of the LIM equations was created using finite volume method with a first-order spatiotemporal Roe Riemann solver.A simplified urban stormwater model(SUSM)considering surface and underground dual drainage system was constructed based on LIM and the US Environmental Protection Agency Storm Water Management ***,a complete urban stormwater model(USM)based on the SWEs with the same solution algorithm was used as the evaluation *** results of the SUSM and USM in a highly urbanized area under four rainfall return periods were analyzed and *** results reveal that the performance of the SUSM is highly consistent with that of the USM but with an improvement in computational efficiency of approximately 140%.In terms of the accuracy of the model,the SUSM slightly underestimates the water depth and velocity and is less accurate when dealing with supercritical flow in urban stormwater flood ***,the SUSM can produce comparable results to USM with higher computational efficiency,which provides a simplified and alternative method for urban flood modeling.

关键词： Comparative study Finite volume method Local inertial approximation form Shallow water equations Urban stormwater model

Characteristics of Gas-Liquid Slug Flow in Microchannel by Instantaneous Liquid Film Thickness Measurement

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Journal of Thermal Science 2022年第4期31卷 1194-1205页

作者： SUN Yanhong chen wenjie LU Jinli WANG Changlong School of Civil Engineering and Architecture Anhui University of TechnologyMa'anshan 243002China

This paper seeks to decipher the exact relationship between the liquid film thickness and the hydrodynamics of gas-liquid slug flows. An instantaneous measurement system is developed by integrating the laser focus displacement meter(LFDM) and high-speed camera to characterize the temporal evolution of the liquid film and the dynamic characteristics of continuous slug flows. A glass tube with internal diameter of 0.75 mm is used and the tested ranges of superficial gas and liquid velocities are 0.01–1.2 m/s and 0.01–0.09 m/s respectively. The non-zero signals of LFDM representing the bubble slug flows changed from regular periodic intervals to chaotic fluctuations when slug-annular flow pattern appears. The dominant frequencies of the periodic intermittent slug flows increased from about 0.5–2 Hz to nearly 10–20 Hz as the superficial gas velocity rised from 0.025 to 0.78 m/s. The bubble and liquid slug lengths calculated by the time interval of liquid film thickness and bubble velocity correlated well with the empirical model. Meantime, the average value of void fraction derived from the calculation of transient liquid film thickness shows a linear growth with the gas holdup ratio.

关键词： liquid film thickness slug flow bubble/slug length void fraction

A novel flexure-based uniaxial force sensor with large range and high resolution

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Science China(Technological Sciences) 2013年第8期56卷 1940-1948页

作者： chen WeiHai JIANG Jun chen wenjie LIU JingMeng School of Automation Science & Electrical Engineering Beihang University Mechatronics Group Singapore Institute of Manufacturing TechnologySingapore 638075Singapore

High performance force sensors often encounter the conflicting requirements of high resolution and large measurement *** address this problem,this paper presents a conceptual design of a novel uniaxial force sensor with large range and dual-stage force resolutions which enables us to measure forces within a wide range with satisfied *** newly developed force sensor features an aluminum alloy body with a probe to transfer external forces into the sensing *** employs an optical linear encoder to detect the displacement of the sensing *** sensing scheme may immunize outside electromagnetic noises and therefore enhance the performance of the sensor thanks to its digital signal *** this paper,an accurate,analytical model for calculating the static stiffness and dynamics of the system was developed by using pseudo-rigid-body-model(PRBM)*** optimize the design,finite element simulations were *** a prototype sensor was fabricated,preliminary characterization tests were carried out to verify the accuracy of the theoretical model and demonstrate the effectiveness of the *** experiment results indicate that the structure of the new sensor is compact,and it has the ability to measure both micro range and macro range forces within one setup,meanwhile keeps very fine resolutions.

关键词： force sensor compliant mechanism static stiffness bandwidth uncertainty

Unsupervised robust recursive least-squares algorithm for impulsive noise filtering

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Science China(Information Sciences) 2013年第4期56卷 203-212页

作者： chen Jie MA Tao chen wenjie PENG ZhiHong School of Automation Beijing Institute of Technology Key Laboratory of Complex System Intelligent Control and Decision(Beijing Institute of Technology) Ministry of Education

A robust recursive least-squares(RLS) adaptive filter against impulsive noise is proposed for the situation of an unknown desired *** minimizing a saturable nonlinear constrained unsupervised cost function instead of the conventional least-squares function,a possible impulse-corrupted signal is prevented from entering the filter’s weight updating ***,a multi-step adaptive filter is devised to reconstruct the observed "impulse-free" noisy sequence,and whenever impulsive noise is detected,the impulse contaminated samples are replaced by predictive *** on simulation and experimental results,the proposed unsupervised robust recursive least-square adaptive filter performs as well as conventional RLS filters in "impulse-free" circumstances,and is effective in restricting large disturbances such as impulsive noise when the RLS and the more recent unsupervised adaptive filter fails.

关键词： unsupervised adaptive filtering impulsive noise suppression recursive least-squares algorithm

VISION-BASED RECOGNITION AND GUIDING OF INITIAL WELDING POSITION FOR ARC-WELDING ROBOT

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Chinese Journal of Mechanical Engineering 2005年第3期18卷 382-384页

作者： chen Xizhang Zhu Zhenyou chen wenjie chen Shanben Institute of Welding Engineering Shanghai Jiaotong University Shanghai 200030 China

A method is put forward to realize the recognition and guiding of initial welding position. The weld seams are marked with black lines, which simplify the computational complexity of image processing greatly. A two-time template matching method has been advanced to search for the target point, which is simple and has higher calculation speed. According to the depth computing principle with the special point matching using binocular stereovision, the initial welding position can be confirmed by calculating the middle point of the perpendicular line of two radials in the space. Taking the welding of propellant fuel container for example, good results are obtained with the algorithms. Finally, similar method for terminating welding position is also advanced.

关键词： Arc-welding robot Binocular vision Guide Recognition Propellant fuel container

Urban Flood Mitigation Strategies with Coupled Gray-Green Measures:A Case Study in Guangzhou City,China

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International Journal of Disaster Risk Science 2024年第3期15卷 467-479页

作者： Jiayue Li Jiajun Zeng Guoru Huang wenjie chen School of Civil Engineering and Transportation South China University of TechnologyGuangzhou510640China School of Architecture South China University of TechnologyGuangzhou510640China State Key Laboratory of Subtropical Building and Urban Science South China University of TechnologyGuangzhou510640China College of Water Conservancy and Civil Engineering South China Agricultural UniversityGuangzhou510642China

The integration of gray and green infrastructure has proven to be a feasible approach for managing stormwater in established urban ***,evaluating the specific contributions of such coupled strategies is *** study introduced a novel integrated hydrological-hydrodynamic model that takes into account the layout of low-impact development(LID)facilities along with pipeline alignment and *** results from modeling were used to assess the individual contribution of LID and improved drainage facilities to urban flooding *** selected a natural island in Guangzhou City,China,as the study *** results indicate that combining three LID measures,namely green roofs,sunken green spaces,and permeable pavements,can reduce total runoff by 41.7%to 25.89%for rainfall recurrence periods ranging from 1year to 100 years,and decrease the volume of nodal overflow by nearly half during rainfall events of less than 10-year return *** integrating LID measures with the upgraded gray infrastructure,the regional pipeline overloading condition is substantially alleviated,resulting in a significant improvement in pipeline system *** urban flooding control,it is recommended to integrate sufficient green space and avoid pipe-laying structural issues during urban planning and *** findings may assist stakeholders in developing strategies to best utilize gray and green infrastructure in mitigating the negative eff ects of urban flooding.

关键词： Coupled hydrodynamic model.Gray-green approach Guangzhou City LID.Pipe renovation Urban inundation

Estimation of time series noise covariance using correlation technology

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控制理论与应用（英文版） 2011年第2期9卷 165-170页

作者： Ma, Tao chen, Jie Peng, Zhihong chen, wenjie School of Automation Beijing Institute of Technology Beijing 100081 China Beijing Institute of Technology Beijing 100081 China

Covariance of clean signal and observed noise is necessary for extracting clean signal from a time *** is transferred to calculate the covariance of observed noise and clean signal's MA process,when the clean signal is described by an autoregressive moving average (ARMA) *** the correlations of the innovations data from observed time series to form a least-squares problem,a concisely autocovariance least-square (CALS) method has been proposed to estimate the *** also extended our work to the case of unknown MA process *** between Odelson's autocovariance least-square (ALS) estimation algorithm and the proposed CALS method show that the CALS method could get a much more exact and compact estimation of the covariance than ALS and its extended form.

关键词： Time series Correlation technology Covariance estimation Least-square method