检索结果-南通市图书馆

China Geology 2024年第3期7卷 592-595页

作者： Bo-de Lu Wen-chang Li Xue-long Liu guang-zhi Meng Qi-he Long Hong Zhang Jun-shan Dao Fang-lan Li Jie-hu Zhou Mao-huang Fan Xue Mi Nan Shi Zhen-liang Cao college of Land Resources and Engineering Kunming University of Science and TechnologyKunming 650093China Geological Team 306 of Yunnan Non-ferrous Metals Geological Bureau Kunming 650217China Mengzi Mining and Metallurgy co. Ltd.Mengzi 661199China

*** The Gejiu-Bozhushan-Laojunshan tin-tungsten polymetallic metallogenic belt is located in southeastern *** is bounded by the Mile-Shizong Fault and the Yangzi Plate to the north and west,respectively,while the Honghe Fault represents its southwestern *** is adjacent to the Ailaoshan Fault,and extends to guangxi and Vietnam to the southeast(Fig.1a;Liu JP et al.,2021).

关键词： silver dating southeast

continual learning fault diagnosis:A dual-branch adaptive aggregation residual network for fault diagnosis with machine increments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第6期36卷 361-377页

作者： Bojian CHEN changqing SHEN Juanjuan SHI Lin KONG Luyang TAN Dong WANG Zhongkui ZHU School of Rail Transportation Soochow UniversitySuzhou 215131China China chang guang satellite technology co.ltd Changchun 130102China Department of Industrial Engineering and Management and in the State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200030China

As a data-driven approach, Deep Learning(DL)-based fault diagnosis methods need to collect the relatively comprehensive data on machine fault types to achieve satisfactory performance. A mechanical system may include multiple submachines in the real-world. During condition monitoring of a mechanical system, fault data are distributed in a continuous flow of constantly generated information and new faults will inevitably occur in unconsidered submachines, which are also called machine increments. Therefore, adequately collecting fault data in advance is difficult. Limited by the characteristics of DL, training existing models directly with new fault data of new submachines leads to catastrophic forgetting of old tasks, while the cost of collecting all known data to retrain the models is excessively high. DL-based fault diagnosis methods cannot learn continually and adaptively in dynamic environments. A new continual Learning Fault Diagnosis method(CLFD) is proposed in this paper to solve a series of fault diagnosis tasks with machine increments. The stability–plasticity dilemma is an intrinsic issue in continual learning. The core of CLFD is the proposed Dual-branch Adaptive Aggregation Residual Network(DAARN).Two types of residual blocks are created in each block layer of DAARN: steady and dynamic blocks. The stability–plasticity dilemma is solved by assigning them with adaptive aggregation weights to balance stability and plasticity, and a bi-level optimization program is used to optimize adaptive aggregation weights and model parameters. In addition, a feature-level knowledge distillation loss function is proposed to further overcome catastrophic forgetting. CLFD is then applied to the fault diagnosis case with machine increments. Results demonstrate that CLFD outperforms other continual learning methods and has satisfactory robustness.

关键词： Catastrophic forgetting continual learning Fault diagnosis Knowledge distillation Machine increments Stability-plasticity dilemma

Image motion and experimental study of a 0.1″space pointing measuring instrument for micro-vibration conditions

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第2期36卷 191-200页

作者： Lin LI Li YUAN Li WANG Miaomiao WANG Xiaoxue GONG Jie SUI Yanpeng WU Ran ZHENG Space Optoelectronic Measurement and Perception Lab. Beijing Institute of Control EngineeringBeijing 100190China China Academy of Space technology Beijing 100094China Science and technology on Space Intelligent control Laboratory Beijing 100094China University of Chinese Academy of Sciences Beijing 100049China changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China chang guang satellite technology co. Ltd.Changchun130102China

There exists an increasing need for Milli-Arc-Seconds(MAS)accuracy pointing measurement for current and future space *** meet the 0.1″space pointing measurement accuracy requirements of spacecraft in future,the influence of spacecraft micro-vibration on a 0.1″Space Pointing Measuring Instrument(SPMI)is studied.A Quasi-Zero Stiffness Device(QZSD)with adaptive adjustment and variable stroke was ***,a series of micro-vibration experiments of the SPMI were carried *** influence of the micro-vibration generated by Guidance Navigation control(GNC)attitude control components under different attitudes on the SPMI was *** spread function of image motion in micro-vibration was also ***,the changes of image motion under the micro-vibration environment were evaluated by extracting the gray centroid of the images,and the experiment processes and results are deeply *** results show that the firstorder frequency of the QZSD system is 0.114 Hz,and it is induced by a double pendulum system;the image motion of single flywheel spinning reached 0.015 pixels;whilst the image motion reached 0.03 pixels when three flywheels are combined *** latest findings provide a beneficial theoretical and technical support for the development of spacecraft with 0·1″pointing accuracy.

关键词： Image motion Micro-vibration Milli-arc-seconds Quasi-zero stiffness device Space pointing measuring instrument

Design and Optimization of the CFRP Mirror components

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Photonic Sensors 2017年第3期7卷 270-277页

作者： Lei WEI Lei ZHANG Xiaoxue GONG University of Chinese Academy of Sciences Beijing 100039 China changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China chang guang satellite technology ltd. co Changchun 130000 China

As carbon fiber reinforced polymer （CFRP） material has been developed and demonstrated as an effective material in lightweight telescope reflector manufacturing recently, the authors of this article have extended to apply this material on the lightweight space camera mirror design and fabrication. By CFRP composite laminate design and optimization using finite element method （FEM） analysis, a spherical mirror with φ316 mm diameter whose core cell reinforcement is an isogrid configuration is fabricated. compared with traditional ways of applying ultra-low-expansion glass （ULE） on the CFRP mirror surface, the method of nickel electroplating on the surface effectively reduces the processing cost and difficulty of the CFRP mirror. Through the FEM analysis, the first order resonance frequency of the CFRP mirror components reaches up to 652.3Hz. Under gravity affection coupling with ＋5℃ temperature rising, the mirror surface shape root-mean-square values （RMS） at the optical axis horizontal state is 5.74 nm, which meets mechanical and optical requirements of the mirror components on space camera.

关键词： Pure-CFRP mirror lay-up design bipod integrated optimization

Improved simulation method for urban free-space optical links based on the finite Markov state model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2017年第5期13卷 363-366页

作者：郭少艾李亚添 chang guang satellite technology co. ltd. changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

An improved method is proposed to simulate the scintillation introduced by the turbulence, based on the finite Markov state model. As a contrast to the literatures, uniformly distributed variables take place during a certain state, which contributes to equivalent simulation of the intensity fluctuations with fewer states than the traditional Markov model. It's also discovered that the proposed Markov model with 20 states provides a satisfactory approximation to the experimental results in the auto-covariance analysis. Moreover, the outage probability and mean fading time are more accurate than those of the traditional Markov model with equivalent states.

关键词：马尔可夫模型状态模型自由空间光链路仿真城市协方差分析均匀分布

Off-axis two-mirror laser communication antenna designed using differential equations

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2017年第2期10卷 166-173页

作者： Chunqiu XIA Xing ZHONG changchun Institute of Optics and Fine Mechanics Chinese Academy of Sciences Changchun 130033 China University of Chinese Academy of Sciences Beijing 100049 China chang guang satellite technology co. ltd. Changchun 130033 China

In satellite laser communication technology, which is built between planets and between a planet and the Earth, the optical antenna is the key point. Thus, research on optical system design is important. The off-axis reflective system has no obscuration and hence possesses a high efficiency for energy transfer. This study proposes a novel method for designing a free-form off-axis reflective imaging system. This study also introduces differential equations that depend on Fermat＇s principle and sine condition. Finally, a free-form off-axis two-mirror optical system was designed by using the differential equation method. This system includes one intermediate image plane, in which the field of view （FOV） is -5° to -4° in the y-axis and -1° to 0° in the x-axis. The modulation transfer function was greater than 0.7 at 50 lp/mm, and the efficiency of energy transmission was high. The free-form off-axis two-mirror optical system involves a wide range of application prospects in the optical antenna used in the satellite laser communication systems. Moreover, the design method that used differ- ential equations was proven simple and effective.

关键词： optical antenna design off-axis reflectivesystem satellite laser communication

Development and Prospect of Chinese Lunar Relay communication satellite

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Space(Science & technology) 2021年第1期2021卷 241-254页

作者： Lihua Zhang DFH satellite co. Ltd.China

Relay communication satellites play a very important role on the lunar far side and pole areas exploration *** relay communication satellite was developed to provide relay communication support for the lander and the rover of chang’e-4 mission landing on the far side of the *** entering into the halo mission orbit around Earth-Moon libration point 2 on June 14,2018,it has operated on the orbit more than thirty *** worked very well and provided reliable,continuous relay communication support for the lander and the rover to accomplish the goals of chang’e-4 lunar far side soft landing and patrol exploration *** of the lunar south polar regions is of high scientific interest.A new relay communication satellite for Chinese south pole exploration mission is also under *** system design and on-orbit operation status of Queqiao relay communication satellite were summarized in this *** system concept of the relay communication satellite for lunar south pole exploration missions is ***,the future development and prospect of the lunar relay communication satellite system are given.

关键词： system Relay summarized

Numerical investigation of basic oxygen furnace slag modification with gas bottom-blowing and SiO_(2) modifier

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2023年第7期30卷 1451-1460页

作者： chang Liu Yu-feng Tian Yong-li Xiao Yong-qian Li Yang Li guang-qiang Li Qiang Wang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Ruipu technology Group co. Ltd.Lishui 323900ZhejiangChina Central Research Institute Baoshan Iron&Steel Co.Ltd.Shanghai 201900China

To avoid the volume expansion of basic oxygen furnace (BOF) slag for use in building materials, a hot slag modification process was proposed to reduce free CaO (f-CaO) in the molten slag. A transient 3D numerical model of BOF molten slag modification by SiO_(2) particles was established. The flow and heat transfer of molten slag, movement and dissolution of the modifier, and concentration distribution of f-CaO in slag during the modification of BOF were studied. The distribution of f-CaO concentration is inhomogeneous all over the molten slag. The mixing effect at the slag surface is weaker than that at the half-height plane of the slag. To consume the f-CaO below 2.0 wt.% in the slag, the optimum quantity of the SiO_(2) modifier is 10.0% of the mass of the slag. The fine SiO_(2) particles help attain a lower final mass fraction of f-CaO and a higher SiO_(2) utilization ratio.

关键词： Basic oxygen furnace slag modification SiO_(2)modifier Free CaO Discrete phase model computational fluid dynamics

A Vehicle Detection Method for Aerial Image Based on YOLO

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of computer and communications 2018年第11期6卷 98-107页

作者： Junyan Lu Chi Ma Li Li Xiaoyan Xing Yong Zhang Zhigang Wang Jiuwei Xu chang guang satellite technology co. Ltd. Changchun China Department of Transportation of Jilin Province Changchun China

With the application of UAVs in intelligent transportation systems, vehicle detection for aerial images has become a key engineering technology and has academic research significance. In this paper, a vehicle detection method for aerial image based on YOLO deep learning algorithm is presented. The method integrates an aerial image dataset suitable for YOLO training by pro-cessing three public aerial image datasets. Experiments show that the training model has a good performance on unknown aerial images, especially for small objects, rotating objects, as well as compact and dense objects, while meeting the real-time requirements.

关键词： Vehicle Detection Aerial Image YOLO VEDAI coWC DOTA

A Road Extraction Method Based on Region Growing and Mathematical Morphology from Remote Sensing Images

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of computer and communications 2018年第11期6卷 91-97页

作者： Yunhe Liu Chi Ma Li Li Xiaoyan Xing Yong Zhang Zhigang Wang Jiuwei Xu chang guang satellite technology co. Ltd. Changchun China Department of Transportation of Jilin Province Changchun China

Road traffic is the important driving factor for economic and social development. With the rapid increase of vehicle population, road traffic problems such as traffic jam and traffic accident have become the bottleneck which restricts economic development. In recent years, natural disasters frequently occur in China. Therefore, it is essential to extract road information to compute the degree of road damage for traffic emergency management. A road extraction method based on region growing and mathematical morphology from remote sensing images is proposed in this paper. According to the road features, the remote sensing image is preprocessed to separate road regions from non-road regions preliminarily. After image thresholding, region growing algorithm is used to extract connected regions. Then we sort connected regions by area to exclude the small regions which are probably non-road objects. Finally, the mathematical morphology algorithm is used to fill the holes inside the road regions. The experimental results show that the method proposed can effectively extract roads from remote sensing images. This research also has broad prospects in dealing with traffic emergency management by the government.

关键词： Region Growing Mathematical Morphology Road Extraction Remote Sensing Images