The Basic Shape Classification of Space Debris with Light Curves     

LU Yao  ZHAO Chang-yin 《Chinese Astronomy and Astrophysics》2021,45(2):190-208

We study the machine learning method for classifying the basic shape of space debris in both simulated and observed data experiments, where light curves are used as the input features. In the dataset for training and testing, simulated light curves are derived from four types of debris within different shapes and materials. Observed light curves are extracted from Mini-Mega TORTORA (MMT) database which is a publicly accessible source of space object photometric records. The experiments employ the deep convolutional neural network, make comparisons with other machine learning algorithms, and the results show CNN (Convolutional Neural Network) is better. In simulational experiments, both types of cylinder can be distinguished perfectly, and two other types of satellite have around 90% probability to be classified. Rockets and defunct satellites can achieve 99% success rate in binary classification, but in further sub-classes classifications, the rate becomes relatively lower.  相似文献   

Analysis and Comparison for Fusion Algorithms of Time Transfer     

WANG Wei-xiong  DONG Shao-wu  WU Wen-jun  GUO Dong  ZHANG Jian 《Chinese Astronomy and Astrophysics》2021,45(2):224-235

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Research and Test of Real-time Search Algorithm of Fast Radio Bursts Based on GPU Acceleration     

WANG Jun  CHEN Mao-zheng  PEI Xin  WANG Zhi-qiao 《Chinese Astronomy and Astrophysics》2018,42(2):313-324

In order to satisfy the research need of Nanshan 25 m radio telescope of Xinjiang Astronomical Observatory (XAO) and study the key technology of the planned QiTai radio Telescope (QTT), on the basis of the original CPU (Central Processing Unit)-based real-time search algorithm of FRBs (Fast Radio Bursts), we have studied the GPU (Graphics Processing Unit)-based real-time search algorithm of FRBs, and built the corresponding real-time search system of FRBs. We have made the comparison and analysis on the GPU system and CPU system, the test result shows that under a given searching accuracy, the speed of the GPU-accelerated algorithm is improved by 35–45 times compared with that of the CPU algorithm.  相似文献   

中国地质学会公布第三届科普奖评选结果     

孙莉莉  高梦瑶 《地质论评》2022,68(5):1603-1771

为推动中国地质学会地学科普研学工作的开展,根据 《中国地质学会精品地学研学路线、课程评选办法(试行)》, 学会组织开展了第二批精品地学研学路线、第一批精品地学 研学课程的申报、推荐和评审工作。  相似文献   

Neptune Trojans: a Revisit and a New Membertwo     

Wu Rui-jun  Zhou Lei  Zhou Li-yong 《Chinese Astronomy and Astrophysics》2019,43(2):262-277

Up to now, 17 Neptune Trojan asteroids have been detected with their orbits being well determined by continuous observations. This paper analyzes systematically their orbital dynamics. Our results show that except for two temporary members with relatively short lifespans on Trojan orbits, the vast majority of Neptune Trojans located within their orbital uncertainties may survive in the solar system age. The escaping probability of Neptune Trojans, through slow diffusion in the orbital element space in 4.5 billion years, is estimated to be ～50%. The asteroid 2012 UW177 classified as a Centaur asteroid by the IAU Minor Planet Center currently is in fact a Neptune Trojan. Numerical simulations indicate that it is librating on the tadpole-shaped orbit around the Neptune's L₄ point. It was captured into the current orbit approximately 0.23 million years ago, and will stay there for at least another 1.3 million years in the future. Its high inclination of i ≈ 54^° not only makes it the most inclined Neptune Trojan, but also makes it exhibit the complicated and interesting co-orbital transitions between the leading and trailing Trojans via the quasi-satellite orbit phase.  相似文献   

SONG-China Project: A Global Automated Observation Networktwo     

Yan Zheng-zhou  Lu Xiao-meng  Tian Jian-feng  Zhang Chun-guang  Wang Kun  Deng Li-cai 《Chinese Astronomy and Astrophysics》2018,42(4):609-625

Driven by the technological advancements and scientific objectives, the data acquisition in observational astronomy has been changed greatly in recent years. Fully automated or even autonomous ground-based network of telescopes has now become a tendency for time-domain observational projects. The Stellar Observations Network Group (SONG) is an international collaboration with the participation and contribution of the Chinese astronomy community. The scientific goal of SONG is time-domain astrophysics, such as the astroseismology and the research of variable stars in open clusters. The SONG project aims to build a global network of one-meter telescopes equipped with high-precision and high-resolution spectrographs, and two-channel lucky-imaging cameras. It is the Chinese initiative to install a 50 cm binocular photometry telescope at each SONG node to share the network platform and infrastructure. This work is focused on the design and implementation of SONG/50BiN in technology and methodology, for the ground-based network composed of multiple sites and a variety of instruments.  相似文献   

基于Morgenstern-Price法的南京大报恩寺地宫稳定性分析     

王莎  谌文武  李鹏飞  孙光吉 《地震工程学报》2011,33(Z1)

处于中国南方潮湿多雨环境下的古代土遗址,易受雨水的冲刷和浸渍而导致土质松散及崩塌。本文以南京报恩寺地宫、塔基保护技术为研究对象,通过现场试验和变形监测,分析影响其稳定的因素并运用M-P法对其稳定性进行了计算,提出了适用于地宫加固的方案。  相似文献   

Review of Deep-Penetrating Geochemical Exploration Methods     

Han Zhixuan  Liao Jianguo  Zhang Yulong  Zhang Bimin  Wang Xueqiu 《地球科学进展》2017,32(8):828-838

It is a worldwide challenge to explore the deeply buried deposits. Deep-penetrating geochemical exploration methods were developed to solve the problems of how to get the information of the buried deposits in the covered layer. The methods were successfully used to indicate some buried deposits, but not all kinds of deposits. What is more, a method cannot be used in all kinds of landscapes. In this paper, theories and case studies of deep-penetrating geochemical exploration methods, including mobile metal ions, enzyme leach, leaching of mobile forms of metals in overburden, electro-geochemical extraction method, biogeochemical exploration, nano-metal in geogas were reviewed. Elements migration, unloading mechanism and anomaly models are the most important parts for deep-penetrating geochemistry and need to be further investigated. From the perspective of economic efficiency and applicability, sampling and analyzing procedures should be simplified to improve the stability of all methods.  相似文献   

Jet Deflection by a Quasi-Steady-State Side Wind in the Laboratory     

David J. Ampleford  Andrea Ciardi  Sergey V. Lebedev  Simon N. Bland  Simon C. Bott  Jeremy P. Chittenden  Gareth N. Hall  Adam Frank  Eric Blackman 《Astrophysics and Space Science》2007,307(1-3):29-34

We present experimental data on the steady state deflection of a highly supersonic jet by a side-wind in the laboratory. The use of a long interaction region enables internal shocks to fully cross the jet, leading to the development of significantly more structure in the jet than in previous work with a similar setup (Lebedev et al., 2004). The ability to control the length of the interaction region in the laboratory allows the switch between a regime representing a clumpy jet or wind and a regime similar to a slowly varying mass loss rate. The results indicate that multiple internal oblique shocks develop in the jet and the possible formation of a second working surface as the jet attempts to tunnel through the ambient medium.  相似文献   

基于解析梯度的近地小天体探测机会搜索问题研究木     

任远崔平远  栾恩杰 《天文学报》2008,49(1):45-54

研究近地小天体的探测机会搜索问题．针对交会型探测任务，通过结合变分理论和状态转移矩阵推导了性能指标关于可调参数的解析偏导数，然后在搜索空间中随机生成初始点，并从这些初始点出发利用解析偏导数寻优，从而得到搜索空间内对应潜在发射机会的全部局部极小值点．此方法既在一定程度上保持了传统搜索方法全局搜索的特点，又克服了传统搜索方法的盲目性，因此计算速度获得很大提高．此外该方法可以对探测机会的搜索精度进行有效地控制．  相似文献