A5101981818- Radio Astronomy Observations and Technology
- Antenna Design and Optimization
- Superconducting and THz Device Technology
- Pulsars and Gravitational Waves Research
- High-pressure geophysics and materials
- Advanced Condensed Matter Physics
- Multiferroics and related materials
- Geophysics and Gravity Measurements
- Magnetic and transport properties of perovskites and related materials
- Tribology and Lubrication Engineering
- Speech and Audio Processing
- Astrophysics and Cosmic Phenomena
- Mechanical Failure Analysis and Simulation
- Maternal Mental Health During Pregnancy and Postpartum
- Gas Dynamics and Kinetic Theory
- ECG Monitoring and Analysis
- Superconducting Materials and Applications
- Speech Recognition and Synthesis
- Model Reduction and Neural Networks
- Advanced Sensor and Control Systems
- Medical Image Segmentation Techniques
- COVID-19 Impact on Reproduction
- Advanced Thermodynamics and Statistical Mechanics
- Adversarial Robustness in Machine Learning
- Hydraulic and Pneumatic Systems
Chinese Academy of Sciences
2009-2023
Technical Institute of Physics and Chemistry
2014-2023
Peking University
2020-2022
Tsinghua University
2022
Hong Kong University of Science and Technology
2022
University of Hong Kong
2022
Beijing Institute of Big Data Research
2022
Tongji University
2022
Fudan University
2022
Shanghai Children's Medical Center
2021
We describe an ultra-wide-bandwidth, low-frequency receiver ("UWL") recently installed on the Parkes radio telescope. The system provides continuous frequency coverage from 704 to 4032 MHz. For much of band (~60%) temperature is approximately 22K and remains in a linear regime even presence strong mobile phone transmissions. discuss scientific technical aspects new including its astronomical objectives, as well feed, receiver, digitiser signal-processor design. pipeline routines that form...
Conservation laws are considered to be fundamental of nature.It has broad applications in many fields, including physics, chemistry, biology, geology, and engineering.Solving the differential equations associated with conservation is a major branch computational mathematics.The recent success machine learning, especially deep learning areas such as computer vision natural language processing, attracted lot attention from community mathematics inspired intriguing works combining traditional...
Most of pulsar nulling observations were conducted at frequencies lower than 1400~MHz. We aim to understand the behaviors pulsars relatively high frequency, and check if is caused by a global change magnetosphere. 20 bright are observed 2250~MHz with unprecedented lengths time using Jiamusi 66m telescope. Nulling fractions these estimated, null emission states pulses identified. degrees scales emission-null pairs calculated describe distributions lengths. Three pulsars, PSRs J0248+6021,...
In this communication, we present a new optimization and realization of quadruple-ridge flared horn (QRFH) as feed for reflector antennas the square kilometer array (SKA) project. The QRFH has been numerically optimized by spline-defined profiles both ridges sidewall, with conical cavity in back short maximum aperture efficiency. final efficiency better than (for horizontal polarization) or around vertical 78% over 4.6-8 GHz, 70% 8-15 65% 15-20 60% 20-24 GHz SKA offset-Gregorian...
PSR B0919+06 generally radiates radio pulses in a normal phase range. It has been known for its occasional perplexing abnormal emission events wherein individual come to an earlier range few tens of periods and then returns usual phase. Heretofore, only such have available study. We observed about 30 hours using the Jiamusi 66-m telescope at Deep Space Station S-band, detected 92 events. identify four types based on abrupted or gradual phase-shifting pulses. The are seen occur randomly some...
An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy Sciences. This turbo-expander designed performance testing research on with different sizes from liquid hydrogen temperature to room region. A measurement control system based Siemens PLC S7-300 this developed. Proper sensors are selected measure such parameters as temperature, pressure, rotation speed air flow rate. All collected data...
Abstract The Five-hundred-metre Aperture Spherical Telescope (FAST) is being constructed in China. With an illuminated aperture of 300-m diameter, it will be the most sensitive single-dish radio telescope world. We calculate beam patterns, gains, and efficiencies FAST at 200 MHz, 1.4 GHz, 3 GHz. A program developed to structural parameters construct models. three-dimensional patterns are calculated by utilising shooting bouncing ray method. show that, with a coaxial horn feed, has pattern...
Abstract The Five-hundred-metre Aperture Spherical Telescope (FAST) uses adaptive spherical panels to achieve a huge collecting area for radio waves. In this paper, we try explore the optimal parameters curvature radius of and focal distance by comparison calculated beam patterns. We show that get best shape maximum gain, is around 300 m, small shift in few cm needed. aperture efficiency can be improved ~10% at 3 GHz shift. also optimise panel positioning beam, find shifts mm improve pattern...
By considering strict relativistic energy of single particle and using the methods quantum statisticsþ aAthe paramagnetism a weakly interacting Fermi gas in weak magnetic filed is studied, most probable paramagnetic susceptibil- ity as well average susceptibility system are solved. On basis, influences effect on sys- tem discussed, critical value number given. It shown that, comparing with nonrelativistic situation þ aAwhen, mag- netic have not changed. When effects make display easily...
We present the Band B feed system over 4.6-24 GHz designed for Square Kilometre Array (SKA) reflector radio astronomy applications. The is a Quad-ridge Flared Horn (QRFH) with customized shape based on spline-defined profiles to achieve improved wideband performance. shows high aperture efficiency and sensitivity SKA in predictions measured beam patterns. design overview, cryogenic dewar concept measurement of receiver noise (10-20 K) low-noise amplifiers, full simulation
The Five-hundred-meter Aperture Spherical Telescope (FAST) is currently being constructed in China. With an illuminated aperture of 300 m diameter, it will be the most sensitive single-dish radio telescope world. Recently we calculate beam patterns numerically and design a wideband feed for FAST. A program developed to construct FAST models at three different zenith angles z=0°, 27° 40°. 200 MHz, 1.4 GHz 3 are calculated by utilizing Shooting Bouncing Ray method. results show that has...
Fusion reactors require high-speed pumping of helium, deuterium and tritium while maintaining the inventory in pumps at a low level. Cryopumping is potentially most attractive method for this task. Cryosorption pump using rare-gas as sorbent good choice to satisfy its special characters. Although large number works have been published recent years on properties cryosorption sorbent, it hard understand behavior fluid frost layer due expensive strict experiment conditions. Molecular modeling...
The Five-hundred-metre Aperture Spherical Telescope (FAST) uses adaptive spherical panels to achieve a huge collecting area for radio waves. In this paper, we try explore the optimal parameters curvature radius of and focal distance by comparison calculated beam patterns. We show that get best shape maximum gain, is around 300 m, small shift in few cm needed. aperture efficiency can be improved ~10% at 3 GHz shift. also optimise panel positioning beam, find shifts mm improve pattern similar...
In this paper, a hybrid measure for automatic scoring of Mandarin pronunciation quality is presented. Different to prevalent algorithms, mono-phone-based and tri-phone-based acoustic models are applied two types features combined get the score ¿goodness pronunciations¿ with support vector machine algorithm, which average logarithm frame-based posterior probability normalized phoneme-based probability. With measure, correlation coefficient between scores from system rater improved 0.8379...
Quadruple-ridge Flared Horns (QRFHs) have been showing qualified performance as the feed antennas for reflecting systems in Square Kilometre Array (SKA). However, due to offset optics of SKA system, identical illuminations from dual polarizations would but result different system performance. This difference become more severe towards high frequencies and may cause worse polarization unqualified desired specification. In this paper, an asymmetrical QRFH working over Band B (4.6–24 GHz) is...
Radio astronomy receiver development is focusing on increasing the field of view and bandwidth in tandem with exponential increase data volumes permitted by signal processing. We present recent processing developments from CSIRO FAST.
In quantitative susceptibility mapping (QSM), the background field removal is an essential data acquisition step because it has a significant effect on restoration quality by generating harmonic incompatibility in measured local data.Even though sparsity based first generation (1GHIRE) model achieved performance gain over traditional approaches, 1GHIRE to be further improved as there basis mismatch underlying numerically solving Poisson's equation for removal.In this paper, we propose second...
A test refrigerator based on the modified Reverse Brayton cycle has been developed in Chinese Academy of Sciences recently. To study behaviors this refrigerator, a dynamic simulation carried out. The numerical model comprises typical components refrigerator: compressor, valves, heat exchangers, expander and heater. This simulator is oriented-object approach each component represented by set differential algebraic equations. control system also simulated, which can be used to optimize...