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The Silk Road (丝绸之路) and Sources of Chinese Medicine Expansion:Part 4 – Miscellaneous Texts
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作者 Sean Bradley 《Chinese Medicine and Culture》 2019年第3期129-131,共3页
Medical works and histories provide a general understanding of foreign influence on Chinese medicine,but a variety of miscellaneous texts give a deeper understanding of the details of this interaction.Trade manuals,no... Medical works and histories provide a general understanding of foreign influence on Chinese medicine,but a variety of miscellaneous texts give a deeper understanding of the details of this interaction.Trade manuals,notes on foreign interactions,archeological discoveries,and religious works all fill in important details on the incorporation of foreign medicines and ideas into Chinese medicine. 展开更多
关键词 Chinese medicine miscellaneous text silk road trade manual
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MISCELLANEOUS
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《外科研究与新技术》 1993年第3期189-189,共1页
930610 The retrospective study on the mortalityof 0-4 years old children in five monitoring vil-lages of Baoying County,Jiangsu Province.JI Ji-ayu(季家鈺).Women & Children Health Center,Baoying County,Baoying,2258... 930610 The retrospective study on the mortalityof 0-4 years old children in five monitoring vil-lages of Baoying County,Jiangsu Province.JI Ji-ayu(季家鈺).Women & Children Health Center,Baoying County,Baoying,225800.Chin RuralHealth Serv Administr 1993;13(3):44-45.According to the monitoring plan laid down bythe Department of Women and Children Affairs,Ministry of Public Health,a basal survey on theacute respiratory infection of the children in thewhole county was engaged.The condition of theretrospective study of the mortality of 0-4 yearsold children in 1990 of 5 monitoring villages(Sishui,Zhangshidang,Wangzhi,Chengjiao andXiaji)was reported and analyzed.There were2227 neonatal live births in 1990.The mortalityof the infants in the 5 monitoring villages was 展开更多
关键词 Jiangsu engaged COUNTY NEONATAL children RETROSPECTIVE miscellaneous mortality BASAL CONGENITAL
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MISCELLANEOUS
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《外科研究与新技术》 1992年第4期237-237,共1页
920754 Injurious effects of TNF-α on viscer-al organs of germ-free rats: a preliminaryreport. SHENG Zhiyong(盛志勇), et al.Postgraduate Med Coll, PLA, 30th Hosp, PLA.Med J Chin PLA 1992; 17(3): 168-170. TNF might be ... 920754 Injurious effects of TNF-α on viscer-al organs of germ-free rats: a preliminaryreport. SHENG Zhiyong(盛志勇), et al.Postgraduate Med Coll, PLA, 30th Hosp, PLA.Med J Chin PLA 1992; 17(3): 168-170. TNF might be one of the most importantcytokines in the process of sepsis. The presentstudy is to evaluate its direct effects on differentorgans. For this purpose, germ-free rats 展开更多
关键词 SEPSIS 盛志勇 ORGANS miscellaneous simultaneous 侯凡凡 BLOOD INTERSTITIAL DIGESTION pathol
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MISCELLANEOUS
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《外科研究与新技术》 1997年第2期128-128,共1页
970395 Screening and genetic analysis of fragile Xsyndrome in Tongling Anhui province of China, SHENYan(沈岩), et al. Basic Med Sci Instit, CAMS &PUMC, Beijing, 100005. Natl Med J China 1997; 77(4): 260-262 Object... 970395 Screening and genetic analysis of fragile Xsyndrome in Tongling Anhui province of China, SHENYan(沈岩), et al. Basic Med Sci Instit, CAMS &PUMC, Beijing, 100005. Natl Med J China 1997; 77(4): 260-262 Objective: To investigate the prevalence of fragile 展开更多
关键词 fragile CAMS 沈岩 ANHUI Screening PREVALENCE miscellaneous transmitting SEVEN BLOTTING
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Astronomical Knowledge Entity Extraction in Astrophysics Journal Articles via Large Language Models 被引量:1
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作者 Wujun Shao Rui Zhang +7 位作者 Pengli Ji Dongwei Fan Yaohua Hu Xiaoran Yan Chenzhou Cui Yihan Tao Linying Mi Lang Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期140-155,共16页
Astronomical knowledge entities,such as celestial object identifiers,are crucial for literature retrieval and knowledge graph construction,and other research and applications in the field of astronomy.Traditional meth... Astronomical knowledge entities,such as celestial object identifiers,are crucial for literature retrieval and knowledge graph construction,and other research and applications in the field of astronomy.Traditional methods of extracting knowledge entities from texts face numerous challenging obstacles that are difficult to overcome.Consequently,there is a pressing need for improved methods to efficiently extract them.This study explores the potential of pre-trained Large Language Models(LLMs)to perform astronomical knowledge entity extraction(KEE)task from astrophysical journal articles using prompts.We propose a prompting strategy called PromptKEE,which includes five prompt elements,and design eight combination prompts based on them.We select four representative LLMs(Llama-2-70B,GPT-3.5,GPT-4,and Claude 2)and attempt to extract the most typical astronomical knowledge entities,celestial object identifiers and telescope names,from astronomical journal articles using these eight combination prompts.To accommodate their token limitations,we construct two data sets:the full texts and paragraph collections of 30 articles.Leveraging the eight prompts,we test on full texts with GPT-4and Claude 2,on paragraph collections with all LLMs.The experimental results demonstrate that pre-trained LLMs show significant potential in performing KEE tasks,but their performance varies on the two data sets.Furthermore,we analyze some important factors that influence the performance of LLMs in entity extraction and provide insights for future KEE tasks in astrophysical articles using LLMs.Finally,compared to other methods of KEE,LLMs exhibit strong competitiveness in multiple aspects. 展开更多
关键词 astronomical databases:miscellaneous virtual observatory tools methods:data analysis
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Leveraging the Empirical Wavelet Transform in Combination with Convolutional LSTM Neural Networks to Enhance the Accuracy of Polar Motion Prediction
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作者 Xu-Qiao Wang Lan Du +2 位作者 Zhong-Kai Zhang Ze-Jun Liu Hao Xiang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第9期214-224,共11页
High-precision polar motion prediction is of great significance for deep space exploration and satellite navigation.Polar motion is affected by a variety of excitation factors,and nonlinear prediction methods are more... High-precision polar motion prediction is of great significance for deep space exploration and satellite navigation.Polar motion is affected by a variety of excitation factors,and nonlinear prediction methods are more suitable for polar motion prediction.In order to explore the effect of deep learning in polar motion prediction.This paper proposes a combined model based on empirical wavelet transform(EWT),Convolutional Neural Networks(CNN)and Long Short Term Memory(LSTM).By training and forecasting EOP 20C04 data,the effectiveness of the algorithm is verified,and the performance of two forecasting strategies in deep learning for polar motion prediction is explored.The results indicate that recursive multi-step prediction performs better than direct multi-step prediction for short-term forecasts within 15 days,while direct multi-step prediction is more suitable for medium and long-term forecasts.In the 365 days forecast,the mean absolute error of EWT-CNN-LSTM in the X direction and Y direction is 18.25 mas and 15.78 mas,respectively,which is 23.5% and 16.2% higher than the accuracy of Bulletin A.The results show that the algorithm has a good effect in medium and long term polar motion prediction. 展开更多
关键词 data analysis methods:miscellaneous ASTROMETRY reference systems EARTH
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Design and Cryogenic Performance of a Hexapod Platform for a Large Ground-based Wide Field Survey Telescope
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作者 Yang Yu Xue-Wen Wang +3 位作者 Yu Zhang Jia-Lin Sun Zhen-Bang Xu Jian-Li Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期178-187,共10页
The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(... The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(as a corrector) is investigated in this paper. First, a ground-based telescope with 2.5 m aperture and 3.5 deg field of view is described. The telescope is under construction, and it is expected to be finished in 2023. Second, the hexapod platform with flexure hinges utilized to adjust the primary focus unit is proposed, which is applied as a corrector.Then, the inverse kinematics of the platform is established and an open-loop control system is built based on it.Finally, the cryogenic performance test for the hexapod platform is performed. The experimental results show that the resolution and repeatability of the translation for the hexapod platform can be achieved at the micrometer level.The resolution and repeatability of the rotation can be achieved at the arc-second level. Therefore, the cryogenic performance of the hexapod platform can meet the optical imaging requirements of the wide-field ground-based telescope. The kinematic analysis and cryogenic performance tests in the paper provide a technical reference for the precise alignment of the primary focus unit and the primary mirror, which can improve the imaging quality of the telescope. 展开更多
关键词 methods:miscellaneous space vehicles:instruments telescopes miscellaneous
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UWLPIPE:Ultra-wide Bandwidth Low-frequency Pulsar Data Processing Pipeline
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作者 Ya-Zhou Zhang Hai-Long Zhang +7 位作者 Jie Wang Jian Li Xin-Chen Ye Shuang-Qiang Wang Xu Du Han Wu Ting Zhang Shao-Cong Guo 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第7期145-157,共13页
For real-time processing of ultra-wide bandwidth low-frequency pulsar baseband data,we designed and implemented an ultra-wide bandwidth low-frequency pulsar data processing pipeline(UWLPIPE)based on the shared ringbuf... For real-time processing of ultra-wide bandwidth low-frequency pulsar baseband data,we designed and implemented an ultra-wide bandwidth low-frequency pulsar data processing pipeline(UWLPIPE)based on the shared ringbuffer and GPU parallel technology.UWLPIPE runs on the GPU cluster and can simultaneously receive multiple 128 MHz dual-polarization VDIF data packets preprocessed by the front-end FPGA.After aligning the dual-polarization data,multiple 128M subband data are packaged into PSRDADA baseband data or multi-channel coherent dispersion filterbank data,and multiple subband filterbank data can be spliced into wideband data after time alignment.We used the Nanshan 26 m radio telescope with the L-band receiver at964~1732 MHz to observe multiple pulsars.Finally,we processed the data using DSPSR software,and the results showed that each subband could correctly fold out the pulse profile,and the wideband pulse profile accumulated by multiple subbands could be correctly aligned. 展开更多
关键词 (stars)pulsars general-methods data analysis-techniques miscellaneous
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First Digit Distributions of Gamma-Ray Bursts
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作者 Hou-Yu Lai Jun-Jie Wei 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第5期70-75,共6页
The occurrence of the first significant digits from real world sources is usually not equally distributed,but is consistent with a logarithmic distribution instead,known as Benford’s law.In this work,we perform a com... The occurrence of the first significant digits from real world sources is usually not equally distributed,but is consistent with a logarithmic distribution instead,known as Benford’s law.In this work,we perform a comprehensive investigation on the first digit distributions of the duration,fluence,and energy flux of gamma-ray bursts (GRBs) for the first time.For a complete GRB sample detected by the Fermi satellite,we find that the first digits of the duration and fluence adhere to Benford’s law.However,the energy flux shows a significant departure from this law,which may be due to the fact that a considerable part of the energy flux measurements is restricted by lack of spectral information.Based on the conventional duration classification scheme,we also check if the durations and fluences of long and short GRBs (with duration T_(90)>2 s and T_(90)≤2 s,respectively) obey Benford’s law.We find that the fluences of both long and short GRBs still agree with the Benford distribution,but their durations do not follow Benford’s law.Our results hint that the long–short GRB classification scheme does not directly represent the intrinsic physical classification scheme. 展开更多
关键词 (stars:)gamma-ray burst general-methods statistical-astronomical databases miscellaneous
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Disturbance Observer-based Pointing Control of Leighton Chajnantor Telescope
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作者 Weirui Chen Zheng Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期135-150,共16页
Leighton Chajnantor Telescope(LCT), i.e., the former Caltech Submillimeter Observatory telescope, will be refurbished at the new site in Chajnantor Plateau, Chile in 2023. The environment of LCT will change significan... Leighton Chajnantor Telescope(LCT), i.e., the former Caltech Submillimeter Observatory telescope, will be refurbished at the new site in Chajnantor Plateau, Chile in 2023. The environment of LCT will change significantly after its relocation, and the telescope will be exposed to large wind disturbances directly because its enclosure will be completely open during observation. The wind disturbance is expected to be a challenge for LCT's pointing control since the existing control method cannot reject this disturbance very well. Therefore, it is very necessary to develop a new pointing control method with good capability of disturbance rejection. In this research, a disturbance observer—based composite position controller(DOB-CPC) is designed, in which an H∞feedback controller is employed to compress the disturbance, and a feedforward linear quadratic regulator is employed to compensate the disturbance precisely based on the estimated disturbance signal. Moreover, a controller switching policy is adopted, which applies the proportional controller to the transient process to achieve a quick response and applies the DOB-CPC to the steady state to achieve a small position error. Numerical experiments are conducted to verify the good performance of the proposed pointing controller(i.e., DOB-CPC) for rejecting the disturbance acting on LCT. 展开更多
关键词 instrumentation:miscellaneous methods:analytical methods:numerical telescopes
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Long-term Integration Ability of the Submillimeter Wave Astronomy Satellite(SWAS)Spectral Line Receivers
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作者 Bing-Ru Wang Di Li +4 位作者 Paul F.Goldsmith Jingwen Wu Chao-Wei Tsai Rudolf Schieder Gary J.Melnick 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期315-322,共8页
The Submillimeter Wave Astronomy Satellite(SWAS)was the first space telescope capable of high spectral resolution observations of terahertz spectral lines.We have investigated the integration ability of its two receiv... The Submillimeter Wave Astronomy Satellite(SWAS)was the first space telescope capable of high spectral resolution observations of terahertz spectral lines.We have investigated the integration ability of its two receivers and spectrometer during five and a half years of on-orbit operation.The CI,O_(2),H_(2)O,and^(13)CO spectra taken toward all observed Galactic sources were analyzed.The present results are based on spectra with a total integration time of up to 2.72×10~4hr(■10~8s).The noise in the spectra is generally consistent with that expected from the radiometer equation,without any sign of approaching a noise floor.This noise performance reflects the extremely stable performance of the passively cooled front end as well as other relevant components in the SWAS instrument throughout its mission lifetime. 展开更多
关键词 telescopes space vehicles:instruments instrumentation:miscellaneous ISM:lines and bands
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A Cross-matching Service for Data Center of Xinjiang Astronomical Observatory
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作者 Hai-Long Zhang Jie Wang +6 位作者 Xin-Chen Ye Wan-Qiong Wang Jia Li Ya-Zhou Zhang Xu Du Han Wu Ting Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期119-127,共9页
Cross-matching is a key technique to achieve fusion of multi-band astronomical catalogs. Due to different equipment such as various astronomical telescopes, the existence of measurement errors, and proper motions of t... Cross-matching is a key technique to achieve fusion of multi-band astronomical catalogs. Due to different equipment such as various astronomical telescopes, the existence of measurement errors, and proper motions of the celestial bodies, the same celestial object will have different positions in different catalogs, making it difficult to integrate multi-band or full-band astronomical data. In this study, we propose an online cross-matching method based on pseudo-spherical indexing techniques and develop a service combining with high performance computing system(Taurus) to improve cross-matching efficiency, which is designed for the Data Center of Xinjiang Astronomical Observatory. Specifically, we use Quad Tree Cube to divide the spherical blocks of the celestial object and map the 2D space composed of R.A. and decl. to 1D space and achieve correspondence between real celestial objects and spherical patches. Finally, we verify the performance of the service using Gaia 3 and PPMXL catalogs. Meanwhile, we send the matching results to VO tools-Topcat and Aladin respectively to get visual results. The experimental results show that the service effectively solves the speed bottleneck problem of crossmatching caused by frequent I/O, and significantly improves the retrieval and matching speed of massive astronomical data. 展开更多
关键词 virtual observatory tools astronomical databases:miscellaneous catalogs
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PSRDP:A Parallel Processing Method for Pulsar Baseband Data
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作者 Ya-Zhou Zhang Hai-Long Zhang +7 位作者 Jie Wang Xin-Chen Ye Shuang-Qiang Wang Xu Du Han Wu Ting Zhang Shao-Cong Guo Meng Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期300-310,共11页
To address the problem of real-time processing of ultra-wide bandwidth pulsar baseband data,we designed and implemented a pulsar baseband data processing algorithm(PSRDP)based on GPU parallel computing technology.PSRD... To address the problem of real-time processing of ultra-wide bandwidth pulsar baseband data,we designed and implemented a pulsar baseband data processing algorithm(PSRDP)based on GPU parallel computing technology.PSRDP can perform operations such as baseband data unpacking,channel separation,coherent dedispersion,Stokes detection,phase and folding period prediction,and folding integration in GPU clusters.We tested the algorithm using the J0437-4715 pulsar baseband data generated by the CASPSR and Medusa backends of the Parkes,and the J0332+5434 pulsar baseband data generated by the self-developed backend of the Nan Shan Radio Telescope.We obtained the pulse profiles of each baseband data.Through experimental analysis,we have found that the pulse profiles generated by the PSRDP algorithm in this paper are essentially consistent with the processing results of Digital Signal Processing Software for Pulsar Astronomy(DSPSR),which verified the effectiveness of the PSRDP algorithm.Furthermore,using the same baseband data,we compared the processing speed of PSRDP with DSPSR,and the results showed that PSRDP was not slower than DSPSR in terms of speed.The theoretical and technical experience gained from the PSRDP algorithm research in this article lays a technical foundation for the real-time processing of QTT(Qi Tai radio Telescope)ultra-wide bandwidth pulsar baseband data. 展开更多
关键词 (stars:)pulsars:general methods:data analysis techniques:miscellaneous
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Design of RFSoC-based Digital Phased Array Feed(PAF)and Hybrid Architecture Beamforming System 被引量:6
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作者 Xin Pei Na Wang +5 位作者 Dan Werthimer Xue-Feng Duan Jian Li Toktonur Ergesh Qi Liu Ming-Hui Cai 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第4期169-184,共16页
As the number of array elements and bandwidth increase,the design challenges of the Phased Array Feed(PAF)front-end and its signal processing system increase.Aiming at the ng-PAF of the 110 m radio telescope,this arti... As the number of array elements and bandwidth increase,the design challenges of the Phased Array Feed(PAF)front-end and its signal processing system increase.Aiming at the ng-PAF of the 110 m radio telescope,this article introduces the concept of fully digital receivers and attempts to use Radio Frequency System-on-Chip(RFSo C)technology to digitize close to the feed array,reduce the complexity and analog components of the front-end,and improve the fidelity of the signals.The article discusses the digital beamforming topology and designs a PAF signal processing experimental system based on RFSo C+GPU hybrid architecture.The system adopts a ZCU111board to design RF-direct digitization and preprocessing front-end,which can sample eight signals up to 2.048GSPS,12 bit,channelize the signals into 1024 chunks,then reorder into four data streams and select one of the 256MHz frequency bands to output through four 10 Gb links.A GPU server is equipped with four RTX 3090 GPUs running four HRBF_HASHPIPE instances,each receiving a 64 MHz bandwidth signal for high-throughput realtime beamforming.The experimental system uses a signal generator to emulate Sa-like signals and propagates through rod antennas,which verifies the effectiveness of the beamforming algorithm.Performance tests show that after algorithm optimization,the average processing time for a given 4 ms data is less than 3 ms in the four-GPU parallel processing mode.The RFSo C integrated design shows significant advantages in power consumption and electromagnetic radiation compared with discrete circuits according to the measurement results. 展开更多
关键词 instrumentation:miscellaneous techniques:miscellaneous telescopes
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Astronomy from Dome A in Antarctica 被引量:4
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作者 Zhaohui Shang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第10期353-384,共32页
Dome A in Antarctica has been demonstrated to be the best site on earth for optical,infrared,and terahertz astronomical observations by more and more evidence,such as excellent free-atmosphere seeing,extremely low per... Dome A in Antarctica has been demonstrated to be the best site on earth for optical,infrared,and terahertz astronomical observations by more and more evidence,such as excellent free-atmosphere seeing,extremely low perceptible water vapor,low sky background,and continuous dark time,etc.In this paper,we present a complete picture of the development of astronomy at Dome A from the very beginning,review recent progress in time-domain astronomy,demonstrate exciting results of the site testing,and address the challenges in instrumentation.Currently proposed projects are briefly discussed. 展开更多
关键词 instrumentation:miscellaneous methods:observational techniques:miscellaneous telescopes atmospheric effects site testing stars:variables:general
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An approximately analytical solution method for the cable-driven parallel robot in FAST 被引量:5
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作者 Jia-Ning Yin Peng Jiang Rui Yao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第2期169-179,共11页
The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-dish aperture telescope with a cable-driven parallel robot introduced to achieve the highest sensitivity in the world.However,to rea... The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the largest single-dish aperture telescope with a cable-driven parallel robot introduced to achieve the highest sensitivity in the world.However,to realize the high-precision,mechanical equations of such a robot are always complicated,so that it is difficult to achieve real-time control by the traditional iterative method.In this regard,this paper proposes an approximately analytical solution method,which uses the approximately linear relationship between the main parameters of FAST to bypass some iterations.With the coefficients of the relationship extracted,static or quasi-static mechanical equations can be analytically solved.In this paper’s example,this method saves at least 90%of the calculating time and the calculated values are consistent with the experimental data.With such huge efficiency improvements,real-time and high-precision control of the FAST will no longer be difficult work.Besides,all the work in this paper is expected to be used in the FAST. 展开更多
关键词 telescopes-methods analytical-instrumentation miscellaneous
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Pulsar timing observations with Haoping Radio Telescope 被引量:4
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作者 Jin-Tao Luo Yu-Ping Gao +8 位作者 Ting-Gao Yang Cheng-Shi Zhao Ming-Lei Tong Yong-Nan Rao Yi-Feng Li Bian Li Xing-Zhi Zhu Hai-Hua Qiao Xiao-Chun Lu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第7期187-192,共6页
We report pulsar timing observations carried out in L-band with NTSC’s 40-meter Haoping Radio Telescope(HRT),which was constructed in 2014.These observations were carried out using the pulsar machine we developed.Tim... We report pulsar timing observations carried out in L-band with NTSC’s 40-meter Haoping Radio Telescope(HRT),which was constructed in 2014.These observations were carried out using the pulsar machine we developed.Timing observations toward millisecond pulsar J0437–4715 obtain a timing residual(r.m.s.)of 397 ns in the time span of 284 days.Our observations successfully detected Crab pulsar’s glitch that happened on 2019 July 23. 展开更多
关键词 radio telescopes instrumentation:miscellaneous methods:data analysis pulsars:general
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A novel hexapod and its prototype for secondary mirror alignment in telescopes 被引量:3
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作者 De-Hua Yang Ying Cheng +2 位作者 Chang-Cheng Wu Fei Fei Zhen-Yu Jin 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第9期113-122,共10页
This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom(6-DOFs) with decoupled translation and rota... This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom(6-DOFs) with decoupled translation and rotation. The decoupled kinematic motions are analyzed and commented on as the alignment mechanism of a secondary mirror from an optical alignment point of view. In terms of performance of the adjustment generally required by the secondary mirror in a telescope, we developed a prototype that uses a novel hexapod design with linear micro-displacement actuators. Especially, in order to achieve high precision, flexures were used to build joints for the hexapod to minimize frictions and eliminate backlashes. Based on the specific configuration and dimension of the prototype hexapod,an analytical model of the reachable workspace was built with the constraints defined by limited rotation angles of the flexure-based joints. We used a laser tracker to verify that the hexapod can reach a spherical translation workspace of φ6 mm and a rotation workspace of±1°. The translational repeatability was tested to be around half a μm by laser displacement sensors. In addition, we also measured the axial and lateral stiffnesses of the hexapod to be around 5500 N mm-^1 and 1750 N mm^-1, respectively. The kinematic analyses and convincing test results jointly encourage implementing the novel hexapod design with decoupled translation and rotation as a favorable alignment mechanism for secondary mirrors in astronomical telescopes. 展开更多
关键词 telescopes --methods analytical - methods miscellaneous - techniques miscellaneous
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Optical system research of multi-object fiber spectroscopic survey telescope 被引量:2
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作者 Hua Bai Ding-Qiang Su +3 位作者 Ming Liang Stephen A.Shectman Xiang-Yan Yuan Xiang-Qun Cui 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第6期199-206,共8页
In the first part of this paper,four different Cassegrain optical systems with their correctors are designed and studied for multi-object fiber slit spectroscopic survey.The aperture in 6.5 m and field of view 3°... In the first part of this paper,four different Cassegrain optical systems with their correctors are designed and studied for multi-object fiber slit spectroscopic survey.The aperture in 6.5 m and field of view 3°are taken for these optical systems.Assuming observation wavelength range is 0.365-0.95μm,the maximum zenith distance for observing is 60°,the maximum diameter of these lenses is 1.66 m,the altitude of the telescope site is 2500 m,two correctors are composed of 4-piece lenses and the other two are 5-piece lenses.The results obtained are:f-ratio about 3.7,the image quality for all four systems with EE80D≤0.60″,the linear diameter of the focal surface is about 1.2 m and 11 000 fibers can be set on it.Considering the limit of size of fused silica and optical glass,the maximum diameter for lens is about 1.7 m.Such a 6.5 m telescope is about the largest one if using the above correctors.Considering the multiobject spectroscopic survey is greatly important,we also studied some telescope optical systems having their aperture near or larger than 10 m used for the multi-object fiber spectroscopic survey.Such ideas are introduced in the last section of this paper. 展开更多
关键词 telescopes techniques:miscellaneous techniques:spectroscopic methods:miscellaneous surveys instrumentation:miscellaneous
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Manufacture of a hollow corner cube retroreflector for next generation of lunar laser ranging 被引量:5
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作者 Yun He Qi Liu +3 位作者 Hui-Zong Duan Jing-Jing He Yuan-Ze Jiang Hsien-Chi Yeh 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第11期55-62,共8页
Lunar laser ranging has made significant contributions to the study of gravitational physics and the Earth-Moon system. The best results for fundamental gravitational experiments have been achieved using lunar laser r... Lunar laser ranging has made significant contributions to the study of gravitational physics and the Earth-Moon system. The best results for fundamental gravitational experiments have been achieved using lunar laser ranging data accumulated so far. However, corner cube retroreflector arrays placed on the Moon currently set a limit on the laser-ranging precision, which is approximately several centimeters for a single photon received. To achieve millimeter precision, next generation of lunar laser ranging using a single hollow retroreflector with a large aperture has been proposed. We developed a prototype hollow retroreflector with a 100-mm aperture using silicate bonding together with a new fabrication method. Dihedral angle offsets of 0.5′′, 0.8′′and 1.9′′were realized, which partly come close to meeting the requirements(offset of 0.6′′for each dihedral angle) for lunar laser ranging. Fluctuation of the wavefront is approximately 1.038λ at 633 nm. A thermal cycle test ranging from -40℃ to +75℃ was carried out for 18.5 periods(approximately 5 d). After this test, the dihedral angle offsets were measured to be 0.39′′, 1.00′′and 2.06′′. The results indicate the potential application of our method for manufacturing a hollow retroreflector with a large aperture to realize lunar laser ranging. 展开更多
关键词 gravitation: instrumentation miscellaneous: Moon
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