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Low beta superconducting cavity system design for HIAF iLinac
Mengxin Xu,Yuan He,Shengxue Zhang,Lubei Liu,Tiancai Jiang,Zehua Liang,Tong Liu,Yue Tao,Chunlong Li,Qitong Huang,Fengfeng Wang,Hao Guo,Feng Bai,Xianbo Xu,Shichun Huang,Xiaoli Li,Zhijun Wang,Shenghu Zha Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7
A superconducting ion-Linac (iLinac), which is supposed to work as the injector in the High Intensity heavy-ion Accelerator Facility project, is under development at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. The iLinac is a superconducting heavy ion linear accelerator approximately 100 meters long and contains 96 superconducting cavities in two types of 17 cyromodules. Two types of superconducting resonators (quarter-wave resonators with a frequency of 81.25 MHz and an optimal beta β = v/c = 0.07 called QWR007 and half-wave resonators with a frequency of 162.5 MHz and an optimal beta β = 0.15 called HWR015) have been investigated. The cavity design included extensive multi-parameter electromagnetic simulations and mechanical analysis, and its results are described in details. The fundamental power coupler and cavity dynamic tuner designs are also presented in this article. The prototypes are under manufacturing and expected to be ready in 2023.
Hot Keyword Extraction of Sci-tech Periodicals Based on the Improved BERT Model
Bing Liu,Zhijun Lv,Nan Zhu,Dongyu Chang,Mengxin Lu 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.6
With the development of the economy and the improvement of living standards, the hot issues in the subject area have become the main research direction, and the mining of the hot issues in the subject currently has problems such as a large amount of data and a complex algorithm structure. Therefore, in response to this problem, this study proposes a method for extracting hot keywords in scientific journals based on the improved BERT model.It can also provide reference for researchers,and the research method improves the overall similarity measure of the ensemble,introducing compound keyword word density, combining word segmentation, word sense set distance, and density clustering to construct an improved BERT framework, establish a composite keyword heat analysis model based on I-BERT framework.Taking the 14420 articles published in 21 kinds of social science management periodicals collected by CNKI(China National Knowledge Infrastructure) in 2017-2019 as the experimental data, the superiority of the proposed method is verified by the data of word spacing, class spacing, extraction accuracy and recall of hot keywords. In the experimental process of this research, it can be found that the method proposed in this paper has a higher accuracy than other methods in extracting hot keywords, which can ensure the timeliness and accuracy of scientific journals in capturing hot topics in the discipline, and finally pass Use information technology to master popular key words.
An Isotache Model for Frozen Soil Taking Account the Effect of Creep on Plastic Yield Pressure
Xiaoliang Yao,Jilin Qi,Xiangping Qiao,Mengxin Liu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2
Plastic yield pressure is a key factor influencing mechanical behavior of frozen soil. In this paper, an isotache model taking account the effect of creep on plastic yield pressure was modified to describe the mechanical behavior of frozen soil. A series K0 compression tests after different creep time and at different temperature were carried out on a fine grained soil obtained from Qinghai-Tibet plateau. Based on analysis of the tested results, it was proved that the strain development of the tested frozen soil obeys the postulation of parallel lines in isotache model. Meanwhile, the development of plastic yield pressure with creep strain is inversely related to temperature, which can be reasonably described by exponential function deduced from the isotache model. The sharp strain increase of frozen soil can be captured by the isotache model when the surcharge loading exceeds the plastic yield pressure. After modifying the isotache model as temperature dependent, mechanical behavior of frozen soil at different temperature can be described reasonably, and the development of plastic yield pressure with creep strain and temperature can be calculated conveniently.
Meng Xin,Tian Jing,Liu Shuai,Li Ruina,Sun Jian,Liu Wenjun 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.3
To evaluate the influence of polyoxymethylene dimethyl ethers (PODE) on particulate matter (PM) chemical features, PM samples emitted from diesel fuel and PODE/diesel blends at volume ratios of 10 %, 20 %, and 30 % (P10, P20, and P30) were characterized using gas chromatography-mass spectrometry, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopic (FT-IR). Results showed that adding PODE in diesel fuel could increase the proportions of the lower carbon-atom-number components and the contents of oxygen-containing compounds in the soluble organic fractions extracted from PM samples. The ratio of oxygen to carbon (O/C), the functional groups, and the nanostructure of dry soot obtained from XPS showed that the O/C rose as the PODE volume ratio increased. The graphitization degree of dry soot decreased in the order: diesel fuel > P10 > P30 > P20. The relative content of hydroxyl functional groups exhibited the same trend, while the relative content of carbonyl functional groups exhibited an opposite trend with the graphitization degree. Moreover, according to FT-IR, both the branching degree and the relative content of hydrocarbon functional groups of aliphatics are influenced by the graphitization degree of dry soot. A turning point at P20 observed by analysis results above indicated that the chemical characteristics of PM could be affected not only by fuel properties but also by the process of fuel combustion and PM formation.