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Study on the Irradiation Characteristics of Laser-Accelerated Proton Beam on SiC
ZHOU Danqing, LI Dongyu, CHEN Yi, LI Yue, YANG Tong, CHENG Hao, WU Minjian, LI Yuze, YAN Yang, XIA Yadong, LIN Chen, YAN Xueqing, ZHAO Ziqiang
Acta Scientiarum Naturalium Universitatis Pekinensis    2022, 58 (3): 405-411.   DOI: 10.13209/j.0479-8023.2022.006
Abstract530)   HTML    PDF(pc) (3552KB)(134)       Save
By irradiating the nuclear material SiC, the characteristics of continuous wide energy spectrum, short pulse and high instantaneous current intensity of the laser-accelerated proton beam have been characterized. The SiC samples were placed at a distance of 4 cm from the target. The 300 shots proton beams were irradiated with a continuous wide energy spectrum proton beam of 1–4.5 MeV, which satisfied the exponential energy spectrum distribution. The surface and cross-section Raman characterizations showed that the intensity of the SiC scattering peaks after irradiation were reduced. The overall trend of Raman cross-section measurement was consistent with the depth of the distribution of energy loss by SRIM simulation. Thus, the experimental characterization of laseraccelerated proton beam with continuous energy distribution was realized. In addition, experiments showed that the short pulse characteristic of the laser-accelerated proton beam could produce a relatively high instantaneous beam current density on the SiC surface. The ultra-fast wide energy spectrum irradiation provides a possibility in simulated reactor neutron irradiation.
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Stock Index Prediction Based on Text Information
Li DONG, Zhongqing WANG, Deyi XIONG
Acta Scientiarum Naturalium Universitatis Pekinensis    2017, 53 (2): 273-278.   DOI: 10.13209/j.0479-8023.2017.037
Abstract1078)   HTML20)    PDF(pc) (384KB)(645)       Save

Sentiment analysis strategy was used to predict stock market index. Support vector machine was applied to construct predict model based on textual information (i.e., lexical information, sentimental words, and sentiment categories) extracted from social media and stock indicators. Experiment results show that the proposed method can obtain the best results, compared with many different predictive model.

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Chinese Syntactic Parsing with Word Sense Disambiguation
LI Dongchen;ZHANG Xiantao;FAN Yang;WU Xihong
   2015, 51 (4): 577-584.   DOI: 10.13209/j.0479-8023.2015.054
Abstract1310)      PDF(pc) (487KB)(350)       Save
This paper proposes an integrated parsing and word sense disambiguation system. The ambiguity problem is solved when introducing semantic knowledge into the parser by modifying the lexical grammar iteratively. Syntactic information is used to deal with polysemous words in the training process. The experimental results show that the new method not only improves the parsing performance, but also has a good performance on word sense disambiguation.option and the closed fuel cycle (CFC) option which consists of the thermal reactor recycle (TRR) and the fast reactor along with thermal reactor recycle (FRR) are calculated. The natural uranium demand, the separate work demand, the nuclear power demand on alternative style of reactors, the nuclear assemblies demand and the disposal demand of nuclear wastes are obtained. According to these results, the FRR option is the optimal strategy with the highest utility of uranium as well as the minimum accumulation of the nuclear wastes.
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