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Temperature detection circuit on the low-temperature superconducting coils

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Nuclear Science and Techniques 2013年第2期24卷 53-58页

作者： SHEN Jie LUO Jiarong Zhenshan chen longwei QIAN Jing MENG Yuedong Institute of Plasma Physics Chinese Academy of Scineces College of Science Donghua University

Experimental Advanced Superconducting Tokamak(EAST) is the fully superconducting *** EAST magnet system comprises 16 D-shaped toroidal field coils and 14 poloidal field coils which are cooled by supercritical helium at 4.2 K and 3.8 *** temperature of superconducting coils is measured by Cernox as a new type low-temperature sensor,and monitored during the cooling and *** helium temperature can offer reference for quench *** this paper,a technique for the weak temperature signal measurement of superconducting coils is introduced,and its weak voltage is extracted from the intrinsic noise of the amplifier by the low-noise instrumentation amplifier,filter circuit,and high-linearity analog *** temperature detection circuit works accurately and safely whether in cooling or operating *** technique is an effective for the temperature detection on the low-temperature superconducting coils.

关键词：温度检测电路超导线圈低温超导托卡马克冷却过程信号测量技术引进操作过程

Liquefaction macrophenomena in the great Wenchuan earthquake

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Earthquake Engineering and Engineering Vibration 2009年第2期8卷 219-229页

作者： chen longwei Yuan Xiaoming Cao Zhenzhong Hou Longqing Sun Rui Dong Lin Wang Weiming Meng Fanchao chen Hongjuan Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China East China Institute of Technology Fuzhou 344000 China

On May 12, 2008 at 14：28, a catastrophic magnitude M 8.0 earthquake struck the Sichuan Province of China. The epicenter was located at Wenchuan （31.00°N, 103.40°E）. Liquefaction macrophenomena and corresponding destruction was observed throughout a vast area of 500 km long and 200 km wide following the earthquake. This paper illustrates the geographic distribution of the liquefaction and the relationship between liquefaction behavior and seismic intensity, and summarizes the liquefaction macrophenomena, including sandboils and waterspouts, ground subsidence, ground fissures etc., and relevant liquefaction features. A brief summary of the structural damage caused by liquefaction is presented and discussed. Based on comparisons with liquefaction phenomena observed in the 1976 Tangshan and 1975 Haicheng earthquakes, preliminary analyses were performed, which revealed some new features of liquefaction behavior and associated issues arising from this event. The site investigation indicated that the spatial non-uniformity of liquefaction distribution was obvious and most of the liquefied sites were located in regions of seismic intensity VIII. However, liquefaction phenomena at ten different sites in regions of seismic intensity VI were also observed for the first time in China mainland. Sandboils and waterspouts ranged from centimeters to tens of meters, with most between 1 m to 3 m. Dramatically high water/sand ejections, e.g., more than 10 m, were observed at four different sites. The sand ejections included silty sand, fine sand, medium sand, course sand and gravel, but the ejected sand amount was less than that in the 1976 Tangshan earthquake. Possible liquefaction of natural gravel soils was observed for the first time in China mainland.

关键词： Wenchuan earthquake post-earthquake investigation liquefaction macrophenomena

The degradation of oxadiazon by nonthermal plasma with a dielectric barrier configuration

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Plasma Science and Technology 2017年第3期19卷 15-26页

作者： Ying ZHAO Risheng YAO Yuedong MENG Jiaxing LI Yiman JIANG longwei chen Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 People＇s Republic of China School of Medical Engineering Hefei University of Technology Hefei 230009 People＇s Republic of China

To explore the feasibility of a degradation approach by non-thermal plasma and the corresponding degradation pathways,studies on the oxadiazon removal in synthetic wastewater by a dielectric barrier discharge plasma reactor were *** loss of the nitro group,dechlorination and ring cleavage is mainly involved in the non-thermal plasma degradation pathways of oxadiazon in a solution based on the OES and LC-MS *** of EC25 and the production of the chlorine ion and nitrate ion further demonstrate the feasibility and validity of the *** conditions with a proper applied voltage,solution flow rate,oxygen flow rate,and solution pH contribute to the plasma degradation processes with a degradation ratio of over 94%.

关键词： oxadiazon wastewater degradation DBD non-thermal plasma

Alkaline diagenesis and its genetic mechanism in the Triassic coal measure strata in the Western Sichuan Foreland Basin,China

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Petroleum Science 2009年第4期6卷 354-365页

作者： Jiang Zaixing Qiu longwei chen Guiju College of Energy China University of GeosciencesBeijing 100083China College of Earth Resources and Information China University of PetroleumShandong 257062China Sinopec Exploration and Production Research Institute Beijing 100083China

The reservoir of the upper Triassic Xujiahe Formation (T3x) in the Western Sichuan Foreland Basin is a set of terrigenous clastic rocks in an environment of coal measure sediments. Diagenesis greatly controls the physical properties of the reservoir through different responses of minerals to acidic and alkaline diagenetic environment. The dissolution of unstable components such as feldspar, rock fragments, carbonate cement, and clay minerals is the major source of secondary pores under acidic diagenesis, while the dissolution of quartz increases the reservoir space in the fault-fold zone of Longmen Mountain and Leikoupo paleo-hills. The dissolution of quartz is a result of cross-formation flow of fluid in the Himalaya epoch and the invasion of alkaline formation water from the Triassic Leikoupo and Jialingjiang formations through fault and fracture systems. In the vertical succession, acidic dissolution occurs at a shallow depth of less than 2,180 m, and alkaline dissolution occurs at a greater depth of more than 2,280 m. The reservoir space is formed by the influence of both acidic and alkaline dissolution in the depth interval of 2,180–2,280 m.

关键词： Sichuan Basin upper Triassic alkaline diagenesis porosity genetic mechanism

Traffic Sign Recognition Based on CNN and Twin Support Vector Machine Hybrid Model

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Journal of Applied Mathematics and Physics 2021年第12期9卷 3122-3142页

作者： Yang Sun longwei chen College of Statistics and Mathematics Yunnan University of Finance and Economics Kunming China

With the progress of deep learning research, convolutional neural networks have become the most important method in feature extraction. How to effectively classify and recognize the extracted features will directly affect the performance of the entire network. Traditional processing methods include classification models such as fully connected network models and support vector machines. In order to solve the problem that the traditional convolutional neural network is prone to over-fitting for the classification of small samples, a CNN-TWSVM hybrid model was proposed by fusing the twin support vector machine (TWSVM) with higher computational efficiency as the CNN classifier, and it was applied to the traffic sign recognition task. In order to improve the generalization ability of the model, the wavelet kernel function is introduced to deal with the nonlinear classification task. The method uses the network initialized from the ImageNet dataset to fine-tune the specific domain and intercept the inner layer of the network to extract the high abstract features of the traffic sign image. Finally, the TWSVM based on wavelet kernel function is used to identify the traffic signs, so as to effectively solve the over-fitting problem of traffic signs classification. On GTSRB and BELGIUMTS datasets, the validity and generalization ability of the improved model is verified by comparing with different kernel functions and different SVM classifiers.

关键词： CNN Twin Support Vector Machine Wavelet Kernel Function Traffic Sign Recognition Transfer Learning

Axial uniformity diagnosis of coaxial surface wave linear plasma by optical emission spectroscopy

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Plasma Science and Technology 2022年第2期24卷 80-92页

作者： Wenjin ZHANG Xinyu WEI longwei chen Qifu LIN Yiman JIANG chengzhou LIU Jiafang SHAN Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031People's Republic of China University of Science and Technology of China Hefei 230026People's Republic of China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031People's Republic of China

The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave *** optical emission spectroscopy,parameters of the argon linear plasma with a length over 600 mm are diagnosed under gas pressure of 30 and 50 Pa and different microwave *** spectral lines of argon and Hβ(486.1 nm)atoms in excited state are observed for estimating electron excitation temperature and electron *** bands in305–310 nm of diatomic OH(Σ-Π+A X22 i)radicals are used to determine the molecule rotational ***,the axial uniformity of electron density and electron excitation temperature are analyzed emphatically under various *** results prove the distinct optimization of compensation from dual powers input,which can narrow the uniform coefficient of electron density and electron excitation temperature by around 40%and 22%*** the microwave power increasing,the axial uniformity of both electron density and electron excitation temperature performs ***,the fluctuation of electron density along the axial direction appeared with higher gas *** axial uniformity of coaxial surface wave linear plasma could be controlled by pressure and power for a better utilization in material processing.

关键词： surface wave plasma low temperature plasma optical emission diagnosis

Exact Travelling Wave Solutions of Two Nonlinear Schrödinger Equations by Using Two Methods

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Journal of Applied Mathematics and Physics 2019年第12期7卷 3101-3115页

作者： Qingmei Zhang Mei Xiong longwei chen College of Statistics and Mathematics Yunnan University of Finance and Economics Kunming Yunnan China

The special kind of (G’/G)-expansion method and the new mapping method are easy and significant mathematical methods. In this paper, exact travelling wave solutions of the higher order dispersive Cubic-quintic nonlinear Schrödinger equation and the generalized nonlinear Schrödinger equation are studied by using the two methods. Finally, the solitary wave solutions, singular soliton solutions, bright and dark soliton solutions and periodic solutions of the two nonlinear Schrödinger equations are obtained. The results show that this method is effective for solving exact solutions of nonlinear partial differential equations.

关键词： The Special Kind of (G’/G)-Expansion Method the New Mapping Method the Partial Differential Equations the Exact Travelling Wave Solutions

Exact Solutions of Two Nonlinear Partial Differential Equations by the First Integral Method

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Advances in Pure Mathematics 2020年第1期10卷 12-20页

作者： Qingmei Zhang Mei Xiong longwei chen College of Statistics and Mathematics Yunnan University of Finance and Economics Kunming China

In recent years, many methods have been used to find the exact solutions of nonlinear partial differential equations. One of them is called the first integral method, which is based on the ring theory of commutative algebra. In this paper, exact travelling wave solutions of the Non-Boussinesq wavepacket model and the (2 + 1)-dimensional Zoomeron equation are studied by using the first integral method. From the solving process and results, the first integral method has the characteristics of simplicity, directness and effectiveness about solving the exact travelling wave solutions of nonlinear partial differential equations. In other words, tedious calculations can be avoided by Maple software;the solutions of more accurate and richer travelling wave solutions are obtained. Therefore, this method is an effective method for solving exact solutions of nonlinear partial differential equations.

关键词： The First Integral Method The Partial Differential Equations The Exact Travelling Wave Solutions

Experimental Study on Ammonia Co-Firing with Coal for Carbon Reduction in the Boiler of a 300-MW Coal-Fired Power Station

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Engineering 2024年第9期40卷 247-259页

作者： Qifu Lin Wangping Sun Haiyan Li Yangjiong Liu Yuwei chen chengzhou Liu Yiman Jiang Yu cheng Ning Ma Huaqing Ya longwei chen Shidong Fang Hansheng Feng Guang-Nan Luo Jiangang Li Kaixin Xiang Jie Cong cheng cheng Institute of Energy Hefei Comprehensive National Science Center(Anhui Energy Laboratory)Hefei 230088China Anbang Technology Co.Ltd Tongling 244000China Institute of Plasma Physics Hefei Institute of Matter ScienceChinese Academy of SciencesHefei 230031China

To reduce CO_(2) emissions from coal-fired power plants,the development of low-carbon or carbon-free fuel combustion technologies has become *** a new zero-carbon fuel,ammonia(NH_(3))can be used to address the storage and transportation issues of hydrogen *** it is not feasible to completely replace coal with ammonia in the short term,the development of ammonia-coal co-combustion technology at the current stage is a fast and feasible approach to reduce CO_(2) emissions from coal-fired power *** study focuses on modifying the boiler and installing two layers of eight pure-ammonia burners in a 300-MW coal-fired power plant to achieve ammonia-coal co-combustion at proportions ranging from 20%to 10%(by heat ratio)at loads of 180-to 300-MW,*** results show that,during ammonia-coal co-combustion in a 300-MW coal-fired power plant,there was a more significant change in NO_(x) emissions at the furnace outlet compared with that under pure-coal combustion as the boiler oxygen levels ***,ammonia burners located in the middle part of the main combustion zone exhibited a better high-temperature reduction performance than those located in the upper part of the main combustion *** all ammonia co-combustion conditions,the NH_(3) concentration at the furnace outlet remained below 1 parts per million(ppm).Compared with that under pure-coal conditions,the thermal efficiency of the boiler slightly decreased(by 0.12%-0.38%)under different loads when ammonia co-combustion reached 15 t·h^(-1).Ammonia co-combustion in coal-fired power plants is a potentially feasible technology route for carbon reduction.

关键词： Coal-fired boiler Coal mixing with ammonia Ammonia-coal co-firing Nitrogen oxide(NO_(x)) CO_(2)reduction Boiler thermal efficiency