Key Laboratory of Radio Astronomy

Nanjing, China

Key Laboratory of Radio Astronomy

Nanjing, China
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Li Q.,CAS National Astronomical Observatories | Li Q.,Key Laboratory of Radio Astronomy | Jiang P.,CAS National Astronomical Observatories | Jiang P.,Key Laboratory of Radio Astronomy | And 2 more authors.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2017

The reflector system of the five-hundred-meter aperture spherical radio telescope (FAST) is designed as rigid panels supported by a flexible cable-net structure. Shape-changing operation in process of observation will lead to relative displacements between the adjacent nodes of the cable-net. Meanwhile, three nodes on a rigid panel are fixed relatively. Thus, adaptive connecting mechanisms between panels and the cable-net are certainly needed to avoid the influence of additional stress during shape-changing operation. The present work focuses on the following aspects according to the technical requirements of FAST. The degrees of freedom and the structure of the adaptive connecting mechanisms are designed, and the finite element model of the reflector system with the adaptive connecting mechanisms is established. Then the theoretical algorithm is applied to verify the results calculated by the finite element analysis. The finite element analysis is carried out to calculate the scope of motion of adaptive connecting mechanisms during the shape-changing of the cable-net, thus providing input parameters for the design of adaptive connecting mechanisms. © 2017 Journal of Mechanical Engineering.


Jiang P.,CAS National Astronomical Observatories | Jiang P.,Key Laboratory of Radio Astronomy | Zhu W.-X.,Guangxi Liugong Machinery Co. | Liu F.,The Beijing Institute of Architectural Design | And 12 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2015

The five hundred-meter Aperture Spherical Radio Telescope (FAST) is supported by a cable-net structure, whose form changing operations would lead to about 500MPa of stress range. This stress range is more than twice that defined by the codes regarding cable-net structures. Thus, the cable-net structure is the most critical and fragile part of the FAST reflector system. Therefore, the present paper mainly focuses on the following two aspects. 1) Based on the estimated tracking trajectory of this telescope during its service life, finite element methods were used to clarify the fatigue resistance requirements for the cables used in this telescope. 2) A new type of steel cable system was developed, one with fatigue resistance and durability capable of meeting that requirement. ©, 2015, Tsinghua University. All right reserved.


Zhou K.,CAS National Astronomical Observatories | Zhou K.,Key Laboratory of Radio Astronomy | Zhou K.,University of Chinese Academy of Sciences | Zhou K.,Paris Observatory | And 9 more authors.
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2016

Terahertz electromagnetic radiation (from 0.1THz to 10THz) that lies in the boundary region between light and radio waves has attracted much attention in recent years due to its certain extraordinary properties. This paper presents the design and simulation investigation of a 0.66THz low-loss subharmonical mixer based on GaAs Schottky barrier diodes. The antiparallel diodes pair is fabricated from China Electronics Technology Group Coporation-13 Institute, flip-chip mounted on a 25um-thick gallium-arsenide substrate. The simulation results exhibits that the conversion loss of the mixer is below 10 dB in the band from 0.6THz to 0.7THz. © IEEE.


Zhang W.,CAS National Astronomical Observatories | Zhang W.,Key Laboratory of Radio Astronomy | Zhong J.Q.,CAS National Astronomical Observatories | Zhong J.Q.,Key Laboratory of Radio Astronomy | And 12 more authors.
Journal of Low Temperature Physics | Year: 2015

We have designed and fabricated superconducting Ti transition edge sensors (TES) with different microbridge lengths varying from 1 to 6 (Formula presented.)m. The current–voltage characteristics of the fabricated Ti TESs are measured at different bath temperatures using a commercial SQUID amplifier. The thermal conductance (G) is found to be about 300 pW/K for a 2.6-(Formula presented.)m-long device. In addition, the effective response time measured with a current pulse signal is about 3 (Formula presented.)s, and decreases with increasing the bias voltage because of negative electro-thermal feedback. The obtained electrical noise equivalent power from the measured current noise is about (Formula presented.) W/Hz(Formula presented.), which is sufficiently low for TeSIA instrument. © 2015 Springer Science+Business Media New York


Li J.,CAS National Astronomical Observatories | Li J.,Key Laboratory of Radio Astronomy | Yang J.-P.,CAS National Astronomical Observatories | Yang J.-P.,Key Laboratory of Radio Astronomy | And 9 more authors.
Journal of Low Temperature Physics | Year: 2015

Microwave kinetic inductance detectors (MKIDs) are promising for THz direct detector arrays of large size, particularly with simple frequency-division multiplexing. Purple Mountain Observatory is developing a terahertz superconducting imaging array (TeSIA) for the DATE5 telescope to be constructed at Dome A, Antarctica. Here we report on the development of a prototype array for the TeSIA, namely an (Formula presented.) CPW MKID array at 0.35 THz. The resonance frequencies of the MKIDs span the 4–5.575 GHz band with an interval of 25 MHz. Each detector is integrated with a twin-slot antenna centered at 0.5 THz and with a relative bandwidth of 10 %, while the whole MKID array with a micro-lens array. Detailed design and measurement results will be presented. © 2015 The Author(s)


Jiang P.,CAS National Astronomical Observatories | Jiang P.,Key Laboratory of Radio Astronomy | Nan R.-D.,CAS National Astronomical Observatories | Nan R.-D.,Key Laboratory of Radio Astronomy | And 4 more authors.
Research in Astronomy and Astrophysics | Year: 2015

The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) is supported by a cable-net structure, whose change in shape leads to a stress range of approximately 500 MPa. This stress range is more than twice the standard recommended value. The cable-net structure is thus the most critical and fragile part of the FAST reflector system. In this study, we first search for a more appropriate deformation strategy that reduces the stress amplitude generated by the process of changing shape. Second, we roughly estimate the tracking trajectory of the telescope during its service life, and conduct an extensive numerical investigation to assess the requirements for fatigue resistance. Finally, we develop a new type of steel cable system that satisfies the cable requirements for construction of FAST. © 2015 National Astronomical Observatories, Chinese Academy of Sciences and IOP Publishing Ltd.


Kong X.,CAS National Astronomical Observatories | Kong X.,Key Laboratory of Radio Astronomy | Kong X.,University of Chinese Academy of Sciences | Jiang P.,CAS National Astronomical Observatories | And 3 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2013

A five-hundred-meter Aperture Spherical radio Telescope (FAST) is supported by a cable-net structure, which enables its surface to form a paraboloid in real time under active control. However, such form-changing operation would lead to about 500MPa of a fatigue stress range for the cable-net structure. This stress range is more than twice as that defined by the relative standard. Therefore, the cable-net structure is the most critical part of a FAST reflector system. Obviously, the fatigue stress will have a significant impact on the reliability of FAST during its service life. The dimensional analysis is used for studying main factor which affects the stress range of structure. Based on the finite element software ANSYS, the form-changing of cable-net structure is simulated. At last, optimal form-changing strategy is proposed for releasing the fatigue stress of cable-net structure, which would be in favor of improving the reliability of a cable-net structure.


Jiang P.,CAS National Astronomical Observatories | Jiang P.,Key Laboratory of Radio Astronomy
2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014 | Year: 2014

The reflector of Five-hundred-meter Aperture Spherical radio Telescope (FAST) is supported by cable-net structure, so that to enable its reflector surface to form a paraboloid from a sphere in real time through active control. However, such form-changing operation would lead to about 500MPa stress range for the cable-net structure. Such stress range is nearly twice as much of that defined by the relative standard. So the cable-net structure is the most critical and expendable part of FAST reflector system. The service life of FAST would directly depend on the residual fatigue life of its cable-net structure. Then, the present paper would make an effort to find a more appropriate deformation strategy to decrease the stress amplitude of the cable during form-changing operation. © 2014 IEEE.

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