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240 results on '"Wei, Da-Ming"'

230. The distances of cosmic γ-ray bursts and their distribution

Author

Wang, Cai-fen and Wei, Da-ming

Subjects
*COSMIC rays, *IONIZING radiation, *GAMMA ray bursts, *GALAXIES
Abstract

Taking the effect of the expansion of the universe, jet effect and the association of γ-ray bursts with supernovae into consideration, we have studied the space distribution of γ-ray bursts. Assuming a Gaussian distribution of the opening angle and that the rate of bursts is proportional to the rate of star formation, we find the best fitting parameters to be φ0=0.1, and σ=0.04, implying that the opening angles are concentrated about O.1 rad, in agreement with the current analyses on γ-ray bursts with known redshifts. The maximum redshift calculated from 〈 V/Vmax 〉 is 4.2, and the energy of γ-ray burst is 1.5 × 1051 ergs. [Copyright &y& Elsevier]

Published
2004
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231. Decomposition Analysis of COD and NH4-N Discharge Reduction of Livestock and Poultry Breeding Industry in China

Author

Zhang, Wen Jing, Wei, Da Ming, Liu, Ya Ling, Guo, Li Qing, and Wu, Yue Ying

Abstract

In order to investigate the emission reduction mechanism for large-scale livestock and poultry breeding industry in China, the structure decomposition analysis model was built, and the total emission reduction effect, the scale effect, the structure effect and the technology effect were analyzed. The results indicate that the total emission reduction effect values of COD and NH4-N were-10.17% and-9.80% respectively, the absolute values of which were decreasing gradually from 2011 to 2013, indicating a decrease trend of the pollutants discharge but with the yearly declined reduction effect. The scale effect values of COD and NH4-N were both 0.32%, which implies the scale expansion of breeding restraining the emission reduction. The structural effect value were 0.99% and-1.91% respectively, namely the breeding structure does not promote the COD discharge reduction but benefits NH4-N discharge reduction. The technology effect values were-11.48% and-8.21% respectively, which means the technology effect is the main driver of COD and NH4-N discharge reduction, and the technology effect of discharge reduction for pig breeding is the key to the total technology effect; while the technology effect of beef cattle obviously restrains the discharge reduction, it is necessary to promote reduction projects and strengthen their surveillance.

Published
2014
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232. THE MAGNETIZATION DEGREE OF THE OUTFLOW POWERING THE HIGHLY POLARIZED REVERSE-SHOCK EMISSION OF GRB 120308A.

Author

Jin, Zhi-Ping, Wei, Da-Ming, and Zhang, Shuai

Subjects
*GAMMA ray bursts, *SUPERGIANT stars, *MAGNETIZATION, *MAGNETIC fields, *ACCRETION disks, *NEUTRINOS, *ACTIVE galactic nuclei
Abstract

GRB 120308A, a long duration γ-ray burst (GRB) detected by Swift, was distinguished by a highly polarized early optical afterglow emission that strongly suggests an ordered magnetic field component in the emitting region. In this work, we model the optical and X-ray emission in the reverse and forward shock scenario and show that the strength of the magnetic field in the reverse-shock region is ∼10 times stronger than that in the forward shock region. Consequently, the outflow powering the highly polarized reverse-shock optical emission was mildly magnetized at a degree of σ ∼ a few percent. Considering the plausible magnetic energy dissipation in both the acceleration and prompt emission phases of the GRB outflow, the afterglow data of GRB 120308A provides us with compelling evidence that, at least for some GRBs, a nonignorable fraction of the energy was released in the form of Poynting flux, confirming the finding first made in the reverse-forward shock emission modeling of the optical afterglow of GRB 990123 by Fan et al. in 2002 and Zhang et al. in 2003. [ABSTRACT FROM AUTHOR]

Published
2015
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233. Local interstellar spectra and solar modulation of cosmic ray electrons and positrons.

Author

Zhu, Cheng-Rui, Yuan, Qiang, and Wei, Da-Ming

Subjects
*SOLAR spectra, *COSMIC rays, *POSITRONS, *SOLAR activity, *ELECTRONS, *PARTICLE acceleration
Abstract

Low energy cosmic rays are modulated by the solar activity when they propagation in the heliosphere, leading to ambiguities in understanding their acceleration at sources and propagation in the Milky Way. By means of the precise measurements of the e − , e + , e − + e + , and e + / (e − + e +) spectra by AMS-02 near the Earth, as well as the very low energy measurements of the e − + e + fluxes by Voyager-1 far away from the Sun, we derive the local interstellar spectra (LIS) of e − and e + components individually. Our method is based on a non-parametric description of the LIS of e − and e + and a force-field solar modulation model. We then obtain the evolution of the solar modulation parameters based on the derived LIS and the monthly fluxes of cosmic ray e − and e + measured by AMS-02. To better fit the monthly data, additional renormalization factors for e − and e + have been multiplied to the modulated fluxes. We find that the inferred solar modulation parameters of positrons are in good agreement with that of cosmic ray nuclei, and the time evolutions of the solar modulation parameters of electrons and positrons differ after the reversal of the heliosphere magnetic field polarity, which shows clearly the charge-sign dependent modulation effect. [ABSTRACT FROM AUTHOR]

Published
2021
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234. Search for gamma-ray spectral lines with the DArk Matter Particle Explorer

Author

Yun-Feng Liang, Francesca Alemanno, Qi An, Philipp Azzarello, Felicia Carla Tiziana Barbato, Paolo Bernardini, Xiao-Jun Bi, Ming-Sheng Cai, Elisabetta Casilli, Enrico Catanzani, Jin Chang, Deng-Yi Chen, Jun-Ling Chen, Zhan-Fang Chen, Ming-Yang Cui, Tian-Shu Cui, Yu-Xing Cui, Hao-Ting Dai, Antonio De Benedittis, Ivan De Mitri, Francesco de Palma, Maksym Deliyergiyev, Margherita Di Santo, Qi Ding, Tie-Kuang Dong, Zhen-Xing Dong, Giacinto Donvito, David Droz, Jing-Lai Duan, Kai-Kai Duan, Domenico D’Urso, Rui-Rui Fan, Yi-Zhong Fan, Fang Fang, Kun Fang, Chang-Qing Feng, Lei Feng, Piergiorgio Fusco, Min Gao, Fabio Gargano, Ke Gong, Yi-Zhong Gong, Dong-Ya Guo, Jian-Hua Guo, Shuang-Xue Han, Yi-Ming Hu, Guang-Shun Huang, Xiao-Yuan Huang, Yong-Yi Huang, Maria Ionica, Wei Jiang, Jie Kong, Andrii Kotenko, Dimitrios Kyratzis, Shi-Jun Lei, Shang Li, Wen-Hao Li, Wei-Liang Li, Xiang Li, Xian-Qiang Li, Yao-Ming Liang, Cheng-Ming Liu, Hao Liu, Jie Liu, Shu-Bin Liu, Yang Liu, Francesco Loparco, Chuan-Ning Luo, Miao Ma, Peng-Xiong Ma, Tao Ma, Xiao-Yong Ma, Giovanni Marsella, Mario Nicola Mazziotta, Dan Mo, Maria Muñoz Salinas, Xiao-Yang Niu, Xu Pan, Andrea Parenti, Wen-Xi Peng, Xiao-Yan Peng, Chiara Perrina, Rui Qiao, Jia-Ning Rao, Arshia Ruina, Zhi Shangguan, Wei-Hua Shen, Zhao-Qiang Shen, Zhong-Tao Shen, Leandro Silveri, Jing-Xing Song, Mikhail Stolpovskiy, Hong Su, Meng Su, Hao-Ran Sun, Zhi-Yu Sun, Antonio Surdo, Xue-Jian Teng, Andrii Tykhonov, Jin-Zhou Wang, Lian-Guo Wang, Shen Wang, Shu-Xin Wang, Xiao-Lian Wang, Ying Wang, Yan-Fang Wang, Yuan-Zhu Wang, Da-Ming Wei, Jia-Ju Wei, Yi-Feng Wei, Di Wu, Jian Wu, Li-Bo Wu, Sha-Sha Wu, Xin Wu, Zi-Qing Xia, En-Heng Xu, Hai-Tao Xu, Zhi-Hui Xu, Zun-Lei Xu, Zi-Zong Xu, Guo-Feng Xue, Hai-Bo Yang, Peng Yang, Ya-Qing Yang, Hui-Jun Yao, Yu-Hong Yu, Guan-Wen Yuan, Qiang Yuan, Chuan Yue, Jing-Jing Zang, Sheng-Xia Zhang, Wen-Zhang Zhang, Yan Zhang, Yi Zhang, Yong-Jie Zhang, Yun-Long Zhang, Ya-Peng Zhang, Yong-Qiang Zhang, Zhe Zhang, Zhi-Yong Zhang, Cong Zhao, Hong-Yun Zhao, Xun-Feng Zhao, Chang-Yi Zhou, Yan Zhu, Francesca Alemanno, Qi An, Philipp Azzarello, Felicia Carla Tiziana Barbato , Paolo Bernardini , Xiao-Jun Bi , Ming-Sheng Cai , Elisabetta Casilli , Enrico Catanzani , Jin Chang , Deng-Yi Chenj , Jun-Ling Chen , Zhan-Fang Chen , Ming-Yang Cui , Tian- Shu Cuin , Yu-Xin Cui , Hao-Ting Dai , Antonio De Benedittis , Ivan De Mitri , Francesco de Palma , Maksym Deliyergiyev Margherita Di Santo , Qi Ding , Tie-Kuan Dong , Zhen-Xing Dong , Giacinto Donvito , David Droz, Jing-Lai Duan , Kai-Kai Duan , Domenico D’Urso , Rui-Rui Fan , Yi-Zhong Fan , Fan Fang , Kun Fang, Chang-Qin Feng , Lei Feng , Piergiorgio Fusco, Min Gao , Fabio Gargano , Ke Gong , Yi-Zhong Gong , Dong- Ya Guo , Jian-Hua Guo , Shuang-Xue Han, Yi-Ming Hu , Guang- Shun Huang , Xiao-Yuan Huang , Yong-Yi Huang , Maria Ionica , Wei Jiang , Jie Kong , Andrii Kotenko , Dimitrios Kyratzis , Shi- Jun Lei, Shang Li , Wen-Hao Li , Wei-Liang Li , Xiang Li , Xian Qiang Li , Yao-Ming Lian , Cheng-Ming Liu , Hao Liu , Jie Liu , Shu-Bin Liu , Yang Liu , Francesco Loparco , Chuan-Ning Luo , Miao Ma , Peng-Xiong Ma , Tao Ma , Xiao-Yong Ma, Giovanni Marsella, Mario Nicola Mazziotta , Dan Mo , Maria Muñoz Salinas , Xiao-Yang Niu , Xu Pan , Andrea Parenti , Wen-Xi Peng , Xiao- Yan Peng , Chiara Perrina , Rui Qiao , Jia-Ning Rao , Arshia Ruina , Zhi Shangguan , Wei-Hua Shen , Zhao-Qiang Shen , Zhong-Tao Shen , Leandro Silveri, Jing-Xing Song , Mikhail Stolpovskiy Hong Su , Meng Su , Hao-Ra Sun , Zhi-Yu Sun , Antonio Surdo , Xue-Jian Teng , Andrii Tykhonov , Jin-Zhou Wang , Lian-Guo Wang , Shen Wang , Shu-Xin Wang , Xiao-Lian Wang , Ying Wang , Yan-Fang Wang , Yuan-Zhu Wang , Da-Ming Wei , Jia-Ju Wei , Yi-Feng Wei , Di Wu , Jian Wu , Li-Bo Wu , Sha-Sha Wun , Xin Wu , Zi-Qing Xi , En-Heng Xu , Hai-Tao Xu , Zhi-Hui Xu , Zun-Lei Xu , Zi-Zong Xu , Guo-Feng Xuen , Hai-Bo Yang , Peng Yang , Ya-Qing Yang , Hui-Jun Yao , Yu-Hong Yu , Guan-Wen Yuan , Qiang Yuan , Chuan Yue , JingJing Zang Sheng-Xi Zhang , Wen-Zhang Zhang , Yan Zhang, Yi Zhangj, Yong-Jie Zhang , Yun-Long Zhang , Ya-Peng Zhang , Yong-Qiang Zhang , Zhe Zhang , Zhi-Yong Zhang , Cong Zhao , Hong-Yun Zhao , Xun-Feng Zhao , Chang-Yi Zhou , and Yan Zhu, Alemanno, Francesca, An, Qi, Azzarello, Philipp, Carla Tiziana Barbato, Felicia, Bernardini, Paolo, Bi, Xiao-Jun, Cai, Ming-Sheng, Casilli, Elisabetta, Catanzani, Enrico, Chang, Jin, Chen, Deng-Yi, Chen, Jun-Ling, Chen, Zhan-Fang, Cui, Ming-Yang, Cui, Tian-Shu, Cui, Yu-Xin, Dai, Hao-Ting, De Benedittis, Antonio, De Mitri, Ivan, DE PALMA, Francesco, Deliyergiyev, Maksym, Di Santo, Margherita, Ding, Qi, Dong, Tie-Kuang, Dong, Zhen-Xing, Donvito, Giacinto, Droz, David, Duan, Jing-Lai, Duan, Kai-Kai, D’Urso, Domenico, Fan, Rui-Rui, Fan, Yi-Zhong, Fang, Fang, Fang, Kun, Feng, Chang-Qing, Feng, Lei, Fusco, Piergiorgio, Gao, Min, Gargano, Fabio, Gong, Ke, Gong, Yi-Zhong, Guo, Dong-Ya, Guo, Jian-Hua, Han, Shuang-Xue, Hu, Yi-Ming, Huang, Guang-Shun, Huang, Xiao-Yuan, Huang, Yong-Yi, Ionica, Maria, Jiang, Wei, Kong, Jie, Kotenko, Andrii, Kyratzis, Dimitrio, Lei, Shi-Jun, Li, Shang, Li, Wen-Hao, Li, Wei-Liang, Li, Xiang, Li, Xian-Qiang, Lian, Yao-Ming, Liu, Cheng-Min, Liu, Hao, Liu, Jie, Liu, Shu-Bin, Liu, Yang, Loparco, Francesco, Luo, Chuan-Ning, Ma, Miao, Ma, Peng-Xiong, Ma, Tao, Ma, Xiao-Yong, Marsella, Giovanni, Nicola Mazziotta, Mario, Mo, Dan, Muñoz Salinas, Maria, Niu, Xiao-Yang, Pan, Xu, Parenti, Andrea, Peng, Wen-Xi, Peng, Xiao-Yan, Perrina, Chiara, Qiao, Rui, Ra, Jia-Ning, Ruina, Arshia, Shangguan, Zhi, Shen, Wei-Hua, Shen, Zhao-Qiang, Shen, Zhong-Tao, Silveri, Leandro, Song, Jing-Xing, Stolpovskiy, Mikhail, Su, Hong, Su, Meng, Sun, Hao-Ran, Sun, Zhi-Yu, Surdo, Antonio, Teng, Xue-Jian, Tykhonov, Andrii, Wang, Jin-Zhou, Wang, Lian-Guo, Wang, Shen, Wang, Shu-Xin, Wang, Xiao-Lian, Wang, Ying, Wang, Yan-Fang, Wang, Yuan-Zhu, Wei, Da-Ming, Wei, Jia-Ju, Wei, Yi-Feng, Wu, Di, Wu, Jian, Wu, Li-Bo, Wu, Sha-Sha, Wu, Xin, Xia, Zi-Qing, Xu, En-Heng, Xu, Hai-Tao, Xu, Zhi-Hui, Xu, Zun-Lei, Xu, Zi-Zong, Xue, Guo-Feng, Yang, Hai-Bo, Yang, Peng, Yang, Ya-Qing, Yao, Hui-Jun, Yu, Yu-Hong, Yuan, Guan-Wen, Yuan, Qiang, Yue, Chuan, Zann, Jing-Jing, Zhan, Sheng-Xia, Zhan, Wen-Zhang, Zhan, Yan, Zhan, Yi, Zhang, Yong-Jie, Zhang, Yun-Long, Zhang, Ya-Peng, Zhang, Yong-Qiang, Zhang, Zhe, Zhang, Zhi-Yong, Zhao, Cong, Zhao, Hong-Yun, Zhao, Xun-Feng, Zhou, Chang-Yi, and Yan Zhu, And

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Line-like structure, High Energy Physics - Experiment (hep-ex), Multidisciplinary, Astrophysics::High Energy Astrophysical Phenomena, DAMPE, Dark matter, Gamma-ray, Line-like structure, Settore FIS/01 - Fisica Sperimentale, DAMPE, Dark matter, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Gamma-ray, High Energy Physics - Experiment
Abstract

The DArk Matter Particle Explorer (DAMPE) is well suitable for searching for monochromatic and sharp $\gamma$-ray structures in the GeV$-$TeV range thanks to its unprecedented high energy resolution. In this work, we search for $\gamma$-ray line structures using five years of DAMPE data. To improve the sensitivity, we develop two types of dedicated data sets (including the BgoOnly data which is the first time to be used in the data analysis for the calorimeter-based gamma-ray observatories) and adopt the signal-to-noise ratio optimized regions of interest (ROIs) for different DM density profiles. No line signals or candidates are found between 10 and 300 GeV in the Galaxy. The constraints on the velocity-averaged cross section for $\chi\chi \to \gamma\gamma$ and the decay lifetime for $\chi \to \gamma\nu$, both at 95% confidence level, have been calculated and the systematic uncertainties have been taken into account. Comparing to the previous Fermi-LAT results, though DAMPE has an acceptance smaller by a factor of $\sim 10$, similar constraints on the DM parameters are achieved and below 100 GeV the lower limits on the decay lifetime are even stronger by a factor of a few. Our results demonstrate the potential of high-energy-resolution observations on dark matter detection., Comment: 14 pages, 8 figures. Update the content to keep up with the published version

Published
2022

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