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26 results on '"Chen, Changqi"'

2. An Empirical Investigation of Correlation between Code Complexity and Bugs

Author

Chen, Changqi

Subjects
Computer Science - Software Engineering
Abstract

There have been many studies conducted on predicting bugs. These studies show that code complexity, such as cyclomatic complexity, correlates with the presence of bugs in code. In this paper, we intend to find the correlation between path complexity and bugs. We found that 1) For simple bugs, there is no strong correlation between the path complexity and the presence of bugs; 2) For complex real-world bugs, though not strong, path complexity has a higher correlation with the presence of bugs than cyclomatic complexity and NPATH complexity. These results are useful for researchers to use the path complexity for building bug prediction models. Moreover, path complexity can be used as a guiding mechanism for test generation.

Published
2019

18. Design, Analysis, and Optimization of the Cryopanel Cooling System for CFETR Torus Cryopump

Author

Chen Chen, Wang Qingsheng, Wang Guodong, Damao Yao, and Chen Changqi

Subjects
010302 applied physics, Nuclear and High Energy Physics, Materials science, business.industry, Nuclear engineering, Torus, Cryopump, Plasma, Computational fluid dynamics, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Coolant, Stress (mechanics), Conceptual design, 0103 physical sciences, Water cooling, business
Abstract

The torus cryopumps in China Fusion Engineering Test Reactor (CFETR) are used to provide required pumping speeds and maintain specified partial pressures for various gases pumped during plasma operation. To begin with, a special structure of the cryopanel cooling system is proposed. However, thermal-hydraulic calculation displayed by computational fluid dynamics X codes shows that the temperature distribution of the structure does not meet the design requirements proposed by the cryogenic properties of the gases pumped. Therefore, an optimized structure relying on hydraulic inflation is adopted to uniform the surface temperature dramatically. Simulation results indicate that the temperature distribution and the stress distribution fulfill the design requirements well. The conceptual design of the cryopanel cooling system provides methods and experience for the overall design of a CFETR torus cryopump in the future.

Published
2018

25. Vacuum System Optimization for EAST Neutral Beam Injector.

Author

Wang, Guodong, Zhang, Si, Chen, Changqi, Tang, Ning, Lang, Jiaqi, and Xie, Yuanlai

Subjects
PLASMA beam injection heating, NEUTRAL beams, MATHEMATICAL optimization, INJECTORS, VACUUM chambers, PLASMA temperature, PLASMA currents, ION beams
Abstract

The neutral beam injector (NBI) generates a high-energy ion beam and neutralizes it, and then relies on drift transmission to inject the formed neutral beam into the fusion plasma to increase the plasma temperature and drive the plasma current. In order to better cooperate with the Experimental Advanced Superconductive Tokamak (EAST), part of the Chinese major national scientific and technological infrastructure, in carrying out long-pulse high-parameter physics experiments of 400 s and above, this paper considers the optimization of the current design and operation of the NBI beam line with a pulse width of 100 s. Based on an upgraded and optimized NBI vacuum chamber and the structure of the beam-line components, the gas-source characteristics under the layout design of the NBI system are analyzed and an NBI vacuum system that meets relevant needs is designed. Using Molflow software to simulate the transport process of gas molecules in the vacuum chamber, the pressure gradient in the vacuum chamber and the heat-load distribution of the low-temperature condensation surface are obtained. The results show that when the NBI system is dynamically balanced, the pressure of each vacuum chamber section is lower than the set value, thus meeting the performance requirements for the NBI vacuum system and providing a basis for subsequent implementation of the NBI vacuum system upgrade using engineering. [ABSTRACT FROM AUTHOR]

Published
2022
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26. 測天約術.

Author

陳昌齊 , 1743-1820, Chen, Changqi , 1743-1820, 陳昌齊 , 1743-1820, and Chen, Changqi , 1743-1820

Abstract

測天約術 -- 楚詞辨韻 -- 呂氏春秋正誤., Ce tian yue shu -- chu ci bian yun -- lü shi chun qiu zheng wu., [陳昌齊]., 框18.18 x14.4 公分, 11行22字, 黑口, 四周單邊, 雙黑魚尾, 版心中鐫書名卷次, 下鐫"粤雅堂校刊"., Kuang 18.18 x14.4 gong fen, 11 hang 22 zi, hei kou, si zhou dan bian, shuang hei yu wei, ban xin zhong juan shu ming juan ci, xia juan"yue ya tang xiao kan"., [Chen Changqi].

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