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1. Characterization and functional analysis of microRNA399 in Cunninghamia lanceolata

Author

F.R. ZHU, Z.B. QIU, Y.M. ZHANG, X. R. ZHANG, and W. L. WANG

Subjects
arabidopsis thaliana, nicotiana benthamiana, pho2, phosphate transporters, rlm-race, Biology (General), QH301-705.5, Plant ecology, QK900-989
Abstract

The miR399 is a conserved microRNA (miRNA) family, and it has been characterized as an essential regulator of phosphorus transport in plants. However, the biological function of miR399 in Cunninghamia lanceolata is still largely unclear. In this study, the comparison of mature miR399 sequence revealed a high similarity between Arabidopsis thaliana and C. lanceolate, and the pre-miR399 was capable of forming a typical stem-loop hairpin structure. A gene PHOSPHATE 2 (PHO2) was identified as a target of cln-miR399 using 5' rapid amplification of cDNA ends. Furthermore, the relationship between cln-miR399 and PHO2 was further confirmed through a transient co-expression of both genes in Nicotiana benthamiana. To examine the function of miR399 in Arabidopsis, miR399-overexpressing transgenic Arabidopsis thaliana was acquired using Agrobacterium-mediated approach. Real-time PCR showed that the amount of cln-MIR399 transcripts was higher in miR399-overexpressing plants than in wild-type plants, which was accompanied with down-regulation of expression of its target gene AtPHO2. The P content was 1.40 to 1.56-fold higher in the leaves of three transgenic lines than in wild type plants. However, the P content in the roots of the three transgenic lines was 24.5 - 37.2 % less than that in wild type plants. Moreover, the transcriptions of three phosphate transporter genes (PHT1, PHT2, and PHT3) were up-regulated in roots of miR399-overexpressing Arabidopsis plants. Interestingly, the transgenic lines exhibited retarded growth under normal P conditions compared with the wild type. Our findings demonstrate that cln-miR399 may play crucial roles in P transport and plant growth via regulation of its target gene PHO2.

Published
2020
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3. Design and Testing of the Front-End Electronics of WCDA in LHAASO

Author

F. Aharonian, Q. An, null Axikegu, L.X. Bai, Y.X. Bai, Y.W. Bao, D. Bastieri, X.J. Bi, Y.J. Bi, H. Cai, J.T. Cai, Z. Cao, J. Chang, J.F. Chang, X.C. Chang, B.M. Chen, J. Chen, L. Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.L. Chen, Y. Chen, N. Cheng, Y.D. Cheng, S.W. Cui, X.H. Cui, Y.D. Cui, B.Z. Dai, H.L. Dai, Z.G. Dai, null Danzengluobu, R.S. Dong, X.J. Dong, J.H. Fan, Y.Z. Fan, Z.X. Fan, J. Fang, K. Fang, C.F. Feng, L. Feng, S.H. Feng, Y.L. Feng, B. Gao, C.D. Gao, Q. Gao, W. Gao, M.M. Ge, L.S. Geng, G.H. Gong, Q.B. Gou, J.L. Gu, M.H. Gu, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Guo, Y.A. Han, H.H. He, H.N. He, J.C. He, S.L. He, X.B. He, Y. He, Z.Q. He, M. Heller, Y.K. Hor, C. Hou, X. Hou, H.B. Hu, S. Hu, S.C. Hu, X.J. Hu, D.H. Huang, Q.L. Huang, W.H. Huang, X.T. Huang, Z.C. Huang, F. Ji, X.L. Ji, H.Y. Jia, K. Jiang, Z.J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B.B. Li, C. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, K. Li, W.L. Li, X. Li, X.R. Li, Y. Li, Y.Z. Li, Z. Li, E.W. Liang, Y.F. Liang, S.J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y.N. Liu, Z.X. Liu, W.J. Long, R. Lu, H.K. Lv, B.Q. Ma, L.L. Ma, X.H. Ma, J.R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y.C. Nan, B.Y. Pang, P. Pattarakijwanich, Z.Y. Pei, B.D. Piazzoli, M.Y. Qi, J.J. Qin, D. Ruffolo, V. Rulev, A. Saiz, L. Shao, O. Shchegolev, X.D. Sheng, J.R. Shi, C.X. Song, H.C. Song, Yu. V. Stenkin, V. Stepanov, Q.N. Sun, X.N. Sun, Z.B. Sun, P.H.T. Tam, Z.B. Tang, W.W. Tian, D. della Volpe, B.D. Wang, C. Wang, H. Wang, H.G. Wang, J.C. Wang, J.S. Wang, L.P. Wang, L.Y. Wang, R.N. Wang, W. Wang, X.G. Wang, X.J. Wang, X.Y. Wang, Y.D. Wang, Y.J. Wang, Y.P. Wang, Z. Wang, Z.H. Wang, Z.X. Wang, D.M. Wei, J.J. Wei, Y.J. Wei, T. Wen, C.Y. Wu, H.R. Wu, S. Wu, W.X. Wu, X.F. Wu, S.Q. Xi, J. Xia, J.J. Xia, G.M. Xiang, G. Xiao, H.B. Xiao, G.G. Xin, Y.L. Xin, Y. Xing, D.L. Xu, R.X. Xu, L. Xue, D.H. Yan, X.B. Yan, C.W. Yang, F.F. Yang, J.Y. Yang, L.L. Yang, M.J. Yang, R.Z. Yang, S.B. Yang, Y.H. Yao, Z.G. Yao, Y.M. Ye, L.Q. Yin, N. Yin, X.H. You, Z.Y. You, Y.H. Yu, Q. Yuan, H.D. Zeng, T.X. Zeng, W. Zeng, Z.K. Zeng, M. Zha, X.X. Zhai, B.B. Zhang, H.M. Zhang, H.Y. Zhang, J.L. Zhang, J.W. Zhang, L. Zhang, L.X. Zhang, P.F. Zhang, P.P. Zhang, R. Zhang, S.R. Zhang, S.S. Zhang, X. Zhang, X.P. Zhang, Y. Zhang, Y.F. Zhang, Y.L. Zhang, B. Zhao, J. Zhao, L. Zhao, L.Z. Zhao, S.P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J.N. Zhou, P. Zhou, R. Zhou, S.Z. Zhou, X.X. Zhou, C.G. Zhu, F.R. Zhu, H. Zhu, K.J. Zhu, and X. Zuo

Subjects
Nuclear and High Energy Physics, Photomultiplier, Dynamic range, Cherenkov detector, Detector, law.invention, Root mean square, Air shower, Nuclear Energy and Engineering, Observatory, law, Environmental science, Electronics, Electrical and Electronic Engineering, Remote sensing
Abstract

Water Cherenkov detector array (WCDA) is one of the key parts of the Large High Altitude Air Shower Observatory (LHAASO), the construction of which was completed by the end of 2020. The WCDA covers a 78 000-m2 area and there exist 3120 large size photomultiplier tubes (PMTs) in three ponds: 8-in PMTs are used in WCDA pond No. 1 and 20-in PMTs are used in ponds No. 2 and No. 3. The front-end electronics (FEE) system based on multigain measurement technique is designed to achieve both high-precision time and charge measurements over a large dynamic range from single photon electron (S.P.E.) to 4000 P.E. (for water pond No. 1)/1800 P.E. (for water ponds No. 2 and No. 3). To achieve a high-quality clock distribution and phase alignment as well as mixed transmission of data, clock, and commands in one fiber over a long distance, an enhanced white rabbit (WR) technique is used. Testing of all the 350 FEE modules for the WCDA is presented in this article. Test results indicate that the charge resolution is better than 20% at S.P.E. and 1% at 1800/4000 P.E. and the time resolution is better than 300 ps root mean square (rms), which successfully meets the application requirement. All the FEE modules have been fabricated and installed for the LHAASO WCDA from 2018 to 2020, and the initial commissioning operation indicates that the FEEs function well.

Published
2021
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4. The YAG Lidar System Applied in LHAASO

Author

Y. Zhang, X. Li, F.R. Zhu, L. Chen, Y. Wang, L.S. Geng, H. Liu, Qinning Sun, and X.J. Ji

Subjects
Materials science, business.industry, Cherenkov Telescope Array, Laser, law.invention, Optics, Air shower, Lidar, law, Reference beam, Thermal, Physics::Accelerator Physics, business, Beam splitter, Beam (structure)
Abstract

The atmospheric quality plays an import role in the air shower observation by the Wide Field of View Cherenkov Telescope Array (WFCTA) of LHAASO. A YAG imaging lidar system was developed to continuously monitor the calorimetric information. The accuracy of atmospheric monitoring is dependent on the pulse energy, the YAG laser’s beam parameters and the angular repeatability of a High-precision 3D lifting Rotating Platform (HiRoP). Therefore, we designed an optical system for this lidar with a beam splitter to divide the laser beam into a reference beam and a calibrating beam with a certain ratio and coupled the beam paths with the movement of HiRoP. Thus, every pulse energy of the calibrating beam, which has the same energy fluctuation with respect to the reference beam recorded by a power meter, could be calculated by the ratio of the two beams. Great cares were also taken to characterize the beam size, polarization and divergence of the laser. Meanwhile, a high-precision home-made thermotank was designed to control the temperature and humidity to improve the performance and stability of our laser system, which resulting in a thermal fluctuation less than 2 0C inside the container in the winter at an altitude of 4410 m. Finally, the pulse energy fluctuation of the calibrating beam was about 1.5%, much less than that of 9% without the thermotank. As a result, we have successfully attained distinguishable full-WFCTA-view scanning Laser images in different air conditions, which could be used for the atmospheric quality analysis in further.

Published
2021
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5. The Laser calibration system for LHAASO-WFCTA

Author

X. Li, H. Liu, F.R. Zhu, J.J. Xia, Y. Zhang, L. Chen, Q.N. Sun, S.S. Zhang, Yang Wang, and L.S. Geng

Subjects
Physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Laser, law.invention, Telescope, Air shower, Lidar, Optics, law, Observatory, Calibration, business, Cherenkov radiation
Abstract

TheWide Field-of-viewCherenkov Telescope Array (WFCTA) of Large High Altitude Air Shower Observatory (LHAASO) is designed to measure the Cherenkov and fluorescent light created in the extensive air showers by cosmic rays (CRs) from ~30 TeV to several EeV. In order to achieve an end-to-end calibration method for WFCTA, three Laser lidar facilities have been installed at LHAASO. They feature two N2 and one YAG Lasers which direct calibrated and pulsed beams into sky. Light scattered from Laser beams produces tracks recorded by the telescope detectors. The Laser calibration systems are used to investigate properties of the atmosphere and air fluorescence. In this paper, we introduce the design and performance of the Laser facilities at an altitude of 4410 m. Great cares were taken to select the data collected by telescopes at clear nights for our analysis. After excluding the inconsistency of all SiPMs of the telescope, we find that the experimental data of the images collected by telescopes agree noticeably well with Monte Carlo’s simulation.

Published
2021
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6. Atmospheric Depth Models in the Field of View of LHAASO-WFCTA

Author

J.J Xia and F.R Zhu

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Atmospheric model, Atmospheric sciences, Cherenkov Telescope Array, International Standard Atmosphere, Atmosphere, Air shower, Observatory, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Physics::Atmospheric and Oceanic Physics, Cherenkov radiation
Abstract

The Wide Field-of-view Cherenkov Telescope Array (WFCTA) is one of the main components of the Large High Altitude Air Shower Observatory(LHAASO) located in Haizi Mountain,Daocheng County,Sichuan Province.WFCTA probes cosmic rays by observing Cherenkov photons generated by secondary particles in Extensive Air showers.Changes in atmosphere depth will lead to changes in the detection efficiency of WFCTA.Therefore, the variation of atmosphere depth plays an essential role in the calibration of WFCTA. In this proceeding,the temporal variation of atmosphere depth at LHAASO site is studied with the MSIS-90 atmosphere model,and compared with the American standard atmosphere model,Saber satellite experimental data, and observational data collected at the LHAASO site. MSIS-90 is used to obtain monthly atmosphere depth at the LHAASO site.

Published
2021
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7. Corrigendum to 'Performance test of the electromagnetic particle detectors for the LHAASO experiment' [Nucl. Instrum. Methods Phys. Res. A 1001 (2021) 165193]

Author

F. Aharonian, Q. An, null Axikegu, L.X. Bai, Y.X. Bai, Y.W. Bao, D. Bastieri, X.J. Bi, Y.J. Bi, H. Cai, J.T. Cai, Z. Cao, J. Chang, J.F. Chang, X.C. Chang, B.M. Chen, J. Chen, L. Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.L. Chen, Y. Chen, N. Cheng, Y.D. Cheng, S.W. Cui, X.H. Cui, Y.D. Cui, B.Z. Dai, H.L. Dai, Z.G. Dai, null Danzengluobu, D. della Volpe, B. D’Ettorre Piazzoli, X.J. Dong, J.H. Fan, Y.Z. Fan, Z.X. Fan, J. Fang, K. Fang, C.F. Feng, L. Feng, S.H. Feng, Y.L. Feng, B. Gao, C.D. Gao, Q. Gao, W. Gao, M.M. Ge, L.S. Geng, G.H. Gong, Q.B. Gou, M.H. Gu, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Guo, Y.A. Han, H.H. He, H.N. He, J.C. He, S.L. He, X.B. He, Y. He, M. Heller, Y.K. Hor, C. Hou, X. Hou, H.B. Hu, S. Hu, S.C. Hu, X.J. Hu, D.H. Huang, Q.L. Huang, W.H. Huang, X.T. Huang, Z.C. Huang, F. Ji, X.L. Ji, H.Y. Jia, K. Jia, K. Jiang, Z.J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B. Li, B.B. Li, C. Li, F. Li, H. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, K. Li, W.L. Li, X. Li, X.R. Li, Y. Li, Y.Z. Li, Z. Li, E.W. Liang, Y.F. Liang, S.J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y.N. Liu, Z.X. Liu, W.J. Long, R. Lu, H.K. Lv, B.Q. Ma, L.L. Ma, X.H. Ma, J.R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y.C. Nan, B.Y. Pang, P. Pattarakijwanich, Z.Y. Pei, M.Y. Qi, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X.D. Sheng, J.R. Shi, H.C. Song, Yu.V. Stenkin, V. Stepanov, Q.N. Sun, X.N. Sun, Z.B. Sun, P.H. T. Tam, Z.B. Tang, W.W. Tian, B.D. Wang, C. Wang, H. Wang, H.G. Wang, J.C. Wang, J.S. Wang, L.P. Wang, L.Y. Wang, R.N. Wang, W. Wang, X.G. Wang, X.J. Wang, X.Y. Wang, Y.D. Wang, Y.J. Wang, Y.P. Wang, Z. Wang, Z.H. Wang, Z.X. Wang, D.M. Wei, J.J. Wei, Y.J. Wei, T. Wen, C.Y. Wu, H.R. Wu, S. Wu, W.X. Wu, X.F. Wu, S.Q. Xi, J. Xia, J.J. Xia, G.M. Xiang, G. Xiao, H.B. Xiao, G.G. Xin, Y.L. Xin, Y. Xing, D.L. Xu, R.X. Xu, L. Xue, D.H. Yan, C.W. Yang, F.F. Yang, J.Y. Yang, L.L. Yang, M.J. Yang, R.Z. Yang, S.B. Yang, Y.H. Yao, Z.G. Yao, Y.M. Ye, L.Q. Yin, N. Yin, X.H. You, Z.Y. You, Y.H. Yu, Q. Yuan, H.D. Zeng, T.X. Zeng, W. Zeng, Z.K. Zeng, M. Zha, X.X. Zhai, B.B. Zhang, H.M. Zhang, H.Y. Zhang, J.L. Zhang, J.W. Zhang, L. Zhang, L.X. Zhang, P.F. Zhang, P.P. Zhang, R. Zhang, S.R. Zhang, S.S. Zhang, X. Zhang, X.P. Zhang, Y. Zhang, Y.F. Zhang, Y.L. Zhang, B. Zhao, J. Zhao, L. Zhao, L.Z. Zhao, S.P. Zhao, X. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J.N. Zhou, P. Zhou, R. Zhou, X.X. Zhou, C.G. Zhu, F.R. Zhu, H. Zhu, K.J. Zhu, and X. Zuo

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Detector, Particle, Instrumentation
Published
2022
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8. Performance of LHAASO-WCDA and observation of the Crab Nebula as a standard candle *

Author

F. Aharonian, Q. An, 克古 Axikegu, L.X. Bai, Y.X. Bai, Y.W. Bao, D. Bastieri, X.J. Bi, Y.J. Bi, H. Cai, J.T. Cai, Z. Cao, J. Chang, J.F. Chang, X.C. Chang, B.M. Chen, J. Chen, L. Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.L. Chen, Y. Chen, N. Cheng, Y.D. Cheng, S.W. Cui, X.H. Cui, Y.D. Cui, B.Z. Dai, H.L. Dai, Z.G. Dai, 罗布 Danzengluobu, D. della Volpe, B. D'Ettorre Piazzoli, X.J. Dong, J.H. Fan, Y.Z. Fan, Z.X. Fan, J. Fang, K. Fang, C.F. Feng, L. Feng, S.H. Feng, Y.L. Feng, B. Gao, C.D. Gao, Q. Gao, W. Gao, M.M. Ge, L.S. Geng, G.H. Gong, Q.B. Gou, M.H. Gu, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Guo, Y.A. Han, H.H. He, H.N. He, J.C. He, S.L. He, X.B. He, Y. He, M. Heller, Y.K. Hor, C. Hou, X. Hou, H.B. Hu, S. Hu, S.C. Hu, X.J. Hu, D.H. Huang, Q.L. Huang, W.H. Huang, X.T. Huang, Z.C. Huang, F. Ji, X.L. Ji, H.Y. Jia, K. Jiang, Z.J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B.B. Li, C. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, K. Li, W.L. Li, X. Li, X.R. Li, Y. Li, Y.Z. Li, Z. Li, E.W. Liang, Y.F. Liang, S.J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y.N. Liu, Z.X. Liu, W.J. Long, R. Lu, H.K. Lv, B.Q. Ma, L.L. Ma, X.H. Ma, J.R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y.C. Nan, B.Y. Pang, P. Pattarakijwanich, Z.Y. Pei, M.Y. Qi, B.Q. Qiao, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X.D. Sheng, J.R. Shi, H.C. Song, Yu.V. Stenkin, V. Stepanov, Q.N. Sun, X.N. Sun, Z.B. Sun, P.H.T. Tam, Z.B. Tang, W.W. Tian, B.D. Wang, C. Wang, H. Wang, H.G. Wang, J.C. Wang, J.S. Wang, L.P. Wang, L.Y. Wang, R.N. Wang, W. Wang, X.G. Wang, X.J. Wang, X.Y. Wang, Y.D. Wang, Y.J. Wang, Y.P. Wang, Z. Wang, Z.H. Wang, Z.X. Wang, D.M. Wei, J.J. Wei, Y.J. Wei, T. Wen, C.Y. Wu, H.R. Wu, S. Wu, W.X. Wu, X.F. Wu, S.Q. Xi, J. Xia, J.J. Xia, G.M. Xiang, G. Xiao, H.B. Xiao, G.G. Xin, Y.L. Xin, Y. Xing, D.L. Xu, R.X. Xu, L. Xue, D.H. Yan, C.W. Yang, F.F. Yang, J.Y. Yang, L.L. Yang, M.J. Yang, R.Z. Yang, S.B. Yang, Y.H. Yao, Z.G. Yao, Y.M. Ye, L.Q. Yin, N. Yin, X.H. You, Z.Y. You, Y.H. Yu, Q. Yuan, H.D. Zeng, T.X. Zeng, W. Zeng, Z.K. Zeng, M. Zha, X.X. Zhai, B.B. Zhang, H.M. Zhang, H.Y. Zhang, J.L. Zhang, J.W. Zhang, L. Zhang, L.X. Zhang, P.F. Zhang, P.P. Zhang, R. Zhang, S.R. Zhang, S.S. Zhang, X. Zhang, X.P. Zhang, Y. Zhang, Y.F. Zhang, Y.L. Zhang, B. Zhao, J. Zhao, L. Zhao, L.Z. Zhao, S.P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J.N. Zhou, P. Zhou, R. Zhou, X.X. Zhou, C.G. Zhu, F.R. Zhu, H. Zhu, K.J. Zhu, X. Zuo, and (The LHAASO Collaboration)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Cherenkov detector, Point source, Astrophysics::High Energy Astrophysical Phenomena, Cosmic distance ladder, Gamma ray, Astronomy and Astrophysics, Cosmic ray, Astrophysics, 01 natural sciences, law.invention, Crab Nebula, law, 0103 physical sciences, Spectral energy distribution, Angular resolution, 010306 general physics, Instrumentation
Abstract

The first Water Cherenkov detector of the LHAASO experiment (WCDA-1) has been operating since April 2019. The data for the first year have been analyzed to test its performance by observing the Crab Nebula as a standard candle. The WCDA-1 achieves a sensitivity of 65 mCU per year, with a statistical threshold of 5 . To accomplish this, a 97.7% cosmic-ray background rejection rate around 1 TeV and 99.8% around 6 TeV with an approximate photon acceptance of 50% is achieved after applying an algorithm to separate gamma-induced showers. The angular resolution is measured using the Crab Nebula as a point source to be approximately 0.45° at 1 TeV and better than 0.2° above 6 TeV, with a pointing accuracy better than 0.05°. These values all match the design specifications. The energy resolution is found to be 33% for gamma rays around 6 TeV. The spectral energy distribution of the Crab Nebula in the range from 500 GeV to 15.8 TeV is measured and found to be in agreement with the results from other TeV gamma ray observatories.

Published
2021
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9. Influence of charge trapping on electroluminescence from Si-nanocrystal light emitting structure

Author

Y. Liu, T.P. Chen, L. Ding, M. Yang, J.I. Wong, C.Y. Ng, S.F. Yu, Z.X. Li, C. Yuen, F.R. Zhu, M.C. Tan, and S. Fung

Subjects
Electroluminescence -- Analysis, Dielectric films -- Electric properties, Dielectric films -- Optical properties, Thin films -- Electric properties, Thin films -- Optical properties, Light-emitting diodes -- Electric properties, Light-emitting diodes -- Optical properties, Physics
Abstract

The effect of charge trapping on electroluminescence (EL) from Si nanocrystal (nc-Si) distributed throughout an Si[O.sub.2] thin film, which is synthesized by [Si.sup.+] implantation into an oxide film thermally grown on a p-type Si substrate, is investigated. The results have highlighted the affect of charging in the nc-Si on the light emission efficiency and its stability of nc-Si light-emitting devices.

Published
2007

10. Inspiration from relativistic solar cosmic ray events

Author

F.R. Zhu and R.G. Wang

Subjects
Physics, Nuclear and High Energy Physics, PAMELA detector, Astrophysics::High Energy Astrophysical Phenomena, Solar cycle 23, Astronomy, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Atomic and Molecular Physics, and Optics, Solar cycle, law.invention, law, Health threat from cosmic rays, Physics::Space Physics, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Forbush decrease, Astrophysics::Earth and Planetary Astrophysics, Ultra-high-energy cosmic ray
Abstract

High energy cosmic rays provide significant information about distance celestial bodies. The solar cosmic rays produced at the closest star, the Sun, not only bring us the particle acceleration in interplanetary and at the Sun, but also help us to well understand the high energy processes of galactic cosmic rays. Solar cosmic rays also directly affect the terrestrial environment and human life. During solar cycle 23 two extreme solar cosmic ray events were recorded on 14 July 2000 and 20 January 2005. The former event occurred in the peak years of solar activity had a soft energy spectrum. However, the spectrum of the later event was the hardest in current solar cycle although it happened close the end of solar cycle. We compare their features in the aspects of flares, radio bursts, coronal mass ejections, and solar proton spectra. The reasons of differences in energy release and particle acceleration was discussed, which may be useful for us to study very high energy cosmic rays.

Published
2008
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