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1. Influences of low level of dietary calcium on bone characters in laying hens

Author

S.C. Zhao, X.Q. Teng, D.L. Xu, X. Chi, M. Ge, and S.W. Xu

Subjects
laying hen, low-calcium diet, bone histomorphology, bone mineral density, bone biomechanical property, Animal culture, SF1-1100
Abstract

Cage layer fatigue (CLF), which is commonly caused by calcium deficiency in the feed, leads to loss of structural bone and increase of bone fragility. In order to investigate the influence of low-calcium diets on bone quality and strength, histopathology, and egg quality, 72 laying hens were randomly allocated to 2 groups at 22 wk of age and received low calcium and control calcium until 34 wk, respectively. Egg production, feed consumption, BW, and egg quality were measured throughout. Bone mineral density, bone biomechanical properties, and histomorphology of femurs and tibias were assessed after birds were sacrificed in 26, 30, and 34 wk. The results showed that low-calcium (1.5%) diets decreased BW, feed consumption, and egg production. The broken eggs rate increased, and the eggshell strength and thickness were lower in treated birds than those in control birds at 30 wk and 34 wk. Femoral and tibial bone index and bone mineral density were lower, cortical thicknesses were thinner, and bone length were shorter over time when birds are in a low-calcium diet than those in control birds. In biomechanical properties, the values of stiffness, Young's modulus, and breaking strength were lower in both femurs and tibias in low-calcium hens at 30 wk and 34 wk than those in bones of control hens. In histomorphology of bone, the cortex turned thinner and there were more cavities in cortex and cancellous bone; the trabecular bone network was fewer, thinner, less cohesive, and generally fragmented; and trabeculae were less well-connected in low-calcium birds. Some cell nuclei in cancellous bone disappeared, and vacuolation was observed in bone cells. There appeared osteoid in cortex bone and cancellous bone in tibias. It was concluded that low-calcium diets could facilitate the development of osteoporosis characterized by an increase of osteoid and loss of structural bone and decrease the values of bone quality and strength, accompanied with a decrease in egg production and egg qualities, which may elucidate the developing mechanism of CLF.

Published
2020
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2. 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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3. In-situ calibration of the single-photoelectron charge response of the IceCube photomultiplier tubes

Author

M.G. Aartsen, M. Ackermann, J. Adams, J.A. Aguilar, M. Ahlers, M. Ahrens, C. Alispach, K. Andeen, T. Anderson, I. Ansseau, G. Anton, C. Argüelles, J. Auffenberg, S. Axani, P. Backes, H. Bagherpour, X. Bai, A. Balagopal V., A. Barbano, S.W. Barwick, B. Bastian, V. Baum, S. Baur, R. Bay, J.J. Beatty, K.-H. Becker, J. Becker Tjus, S. BenZvi, D. Berley, E. Bernardini, D.Z. Besson, G. Binder, D. Bindig, E. Blaufuss, S. Blot, C. Bohm, M. Börner, S. Böser, O. Botner, J. Böttcher, E. Bourbeau, J. Bourbeau, F. Bradascio, J. Braun, S. Bron, J. Brostean-Kaiser, A. Burgman, J. Buscher, R.S. Busse, T. Carver, C. Chen, E. Cheung, D. Chirkin, S. Choi, K. Clark, L. Classen, A. Coleman, G.H. Collin, J.M. Conrad, P. Coppin, P. Correa, D.F. Cowen, R. Cross, P. Dave, C. De Clercq, J.J. DeLaunay, H. Dembinski, K. Deoskar, S. De Ridder, P. Desiati, K.D. de Vries, G. de Wasseige, M. de With, T. DeYoung, A. Diaz, J.C. Díaz-Vélez, H. Dujmovic, M. Dunkman, E. Dvorak, B. Eberhardt, T. Ehrhardt, P. Eller, R. Engel, P.A. Evenson, S. Fahey, A.R. Fazely, J. Felde, K. Filimonov, C. Finley, D. Fox, A. Franckowiak, E. Friedman, A. Fritz, T.K. Gaisser, J. Gallagher, E. Ganster, S. Garrappa, L. Gerhardt, K. Ghorbani, T. Glauch, T. Glüsenkamp, A. Goldschmidt, J.G. Gonzalez, D. Grant, Z. Griffith, S. Griswold, M. Günder, M. Gündüz, C. Haack, A. Hallgren, L. Halve, F. Halzen, K. Hanson, A. Haungs, D. Hebecker, D. Heereman, P. Heix, K. Helbing, R. Hellauer, F. Henningsen, S. Hickford, J. Hignight, G.C. Hill, K.D. Hoffman, R. Hoffmann, T. Hoinka, B. Hokanson-Fasig, K. Hoshina, F. Huang, M. Huber, T. Huber, K. Hultqvist, M. Hünnefeld, R. Hussain, S. In, N. Iovine, A. Ishihara, G.S. Japaridze, M. Jeong, K. Jero, B.J.P. Jones, F. Jonske, R. Joppe, D. Kang, W. Kang, A. Kappes, D. Kappesser, T. Karg, M. Karl, A. Karle, U. Katz, M. Kauer, J.L. Kelley, A. Kheirandish, J. Kim, T. Kintscher, J. Kiryluk, T. Kittler, S.R. Klein, R. Koirala, H. Kolanoski, L. Köpke, C. Kopper, S. Kopper, D.J. Koskinen, M. Kowalski, K. Krings, G. Krückl, N. Kulacz, N. Kurahashi, A. Kyriacou, M. Labare, J.L. Lanfranchi, M.J. Larson, F. Lauber, J.P. Lazar, K. Leonard, A. Leszczyńska, M. Leuermann, Q.R. Liu, E. Lohfink, C.J. Lozano Mariscal, L. Lu, F. Lucarelli, J. Lünemann, W. Luszczak, Y. Lyu, W.Y. Ma, J. Madsen, G. Maggi, K.B.M. Mahn, Y. Makino, P. Mallik, K. Mallot, S. Mancina, I.C. Mariş, R. Maruyama, K. Mase, R. Maunu, F. McNally, K. Meagher, M. Medici, A. Medina, M. Meier, S. Meighen-Berger, T. Menne, G. Merino, T. Meures, J. Micallef, D. Mockler, G. Momenté, T. Montaruli, R.W. Moore, R. Morse, M. Moulai, P. Muth, R. Nagai, U. Naumann, G. Neer, H. Niederhausen, M.U. Nisa, S.C. Nowicki, D.R. Nygren, A. Obertacke Pollmann, M. Oehler, A. Olivas, A. O'Murchadha, E. O'Sullivan, T. Palczewski, H. Pandya, D.V. Pankova, N. Park, P. Peiffer, C. Pérez de los Heros, S. Philippen, D. Pieloth, E. Pinat, A. Pizzuto, M. Plum, A. Porcelli, P.B. Price, G.T. Przybylski, C. Raab, A. Raissi, M. Rameez, L. Rauch, K. Rawlins, I.C. Rea, R. Reimann, B. Relethford, M. Renschler, G. Renzi, E. Resconi, W. Rhode, M. Richman, S. Robertson, M. Rongen, C. Rott, T. Ruhe, D. Ryckbosch, D. Rysewyk, I. Safa, S.E. Sanchez Herrera, A. Sandrock, J. Sandroos, M. Santander, S. Sarkar, K. Satalecka, M. Schaufel, H. Schieler, P. Schlunder, T. Schmidt, A. Schneider, J. Schneider, F.G. Schröder, L. Schumacher, S. Sclafani, D. Seckel, S. Seunarine, S. Shefali, M. Silva, R. Snihur, J. Soedingrekso, D. Soldin, M. Song, G.M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, R. Stein, P. Steinmüller, J. Stettner, A. Steuer, T. Stezelberger, R.G. Stokstad, A. Stößl, N.L. Strotjohann, T. Stürwald, T. Stuttard, G.W. Sullivan, I. Taboada, F. Tenholt, S. Ter-Antonyan, A. Terliuk, S. Tilav, K. Tollefson, L. Tomankova, C. Tönnis, S. Toscano, D. Tosi, A. Trettin, M. Tselengidou, C.F. Tung, A. Turcati, R. Turcotte, C.F. Turley, B. Ty, E. Unger, M.A. Unland Elorrieta, M. Usner, J. Vandenbroucke, W. Van Driessche, D. van Eijk, N. van Eijndhoven, S. Vanheule, J. van Santen, M. Vraeghe, C. Walck, A. Wallace, M. Wallraff, N. Wandkowsky, T.B. Watson, C. Weaver, A. Weindl, M.J. Weiss, J. Weldert, C. Wendt, J. Werthebach, B.J. Whelan, N. Whitehorn, K. Wiebe, C.H. Wiebusch, L. Wille, D.R. Williams, L. Wills, M. Wolf, J. Wood, T.R. Wood, K. Woschnagg, G. Wrede, D.L. Xu, X.W. Xu, Y. Xu, J.P. Yanez, G. Yodh, S. Yoshida, T. Yuan, M. Zöcklein, Physics, Faculty of Sciences and Bioengineering Sciences, Vriendenkring VUB, and Elementary Particle Physics

Subjects
electron, Physics - Instrumentation and Detectors, Detector modelling and simulations II (electric fields, Physics::Instrumentation and Detectors, Monte Carlo method, 01 natural sciences, charge distribution, 030218 nuclear medicine & medical imaging, IceCube, 0302 clinical medicine, DESIGN, charge, emission, (photomultipliers, Instrumentation, Photon detectors for UV, physics.ins-det, Mathematical Physics, Physics, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Charge density, calibration [photomultiplier], Monte Carlo [numerical calculations], Instrumentation and Detectors (physics.ins-det), photomultiplier: calibration, Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc), Neutrino detector, HPDs, Physique des particules élémentaires, Neutrino, numerical calculations: Monte Carlo, others), photoelectron, Photomultiplier, data analysis method, pulse formation, Visible and IR photons (vacuum) (photomultipliers, HPDs, others), FOS: Physical sciences, Particle detector, IceCube Neutrino Observatory, 03 medical and health sciences, Optics, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Visible and IR photons (vacuum) (photomultipliers, ddc:610, etc), multiplication and induction, 010308 nuclear & particles physics, business.industry, PERFORMANCE, visible and IR photons (vacuum), charge transport, Physics and Astronomy, electron emission, transport, business
Abstract

Journal of Instrumentation 15(06), P06032 (2020). doi:10.1088/1748-0221/15/06/P06032, We describe an improved in-situ calibration of the single-photoelectron charge distributions for each of the in-ice Hamamatsu Photonics R7081-02[MOD] photomultiplier tubes in the IceCube Neutrino Observatory. The characterization of the individual PMT charge distributions is important for PMT calibration, data and Monte Carlo simulation agreement, and understanding the effect of hardware differences within the detector. We discuss the single photoelectron identification procedure and how we extract the single-photoelectron charge distribution using a deconvolution of the multiple-photoelectron charge distribution., Published by Inst. of Physics, London

Published
2020
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4. The evidential reasoning approach for MADA under both probabilistic and fuzzy uncertainties

Author

J.B. Yang, Y.M. Wang, D.L. Xu, and K.S. Chin

Subjects
Mathematical logic -- Usage, Symbolic and mathematical logic -- Usage, Production management -- Methods, Decision analysis -- Methods, Business, Business, general, Business, international
Abstract

The problems arising while using many multiple attribute decision analysis are addressed by using evidential reasoning approach.

Published
2006

5. 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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6. 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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7. Seal performance test of shield tail under high water pressure

Author

Y. Bai, Xi Jiang, W. Chen, D.L. Xu, and X.H. Zhang

Subjects
Pipeline transport, Shield machine, Petroleum engineering, Lateral earth pressure, Shield, Grease, Environmental science, Static pressure, Water pressure, Seal (mechanical)
Abstract

Shield method has been used for more tunnels projects due to its safety and high efficiency. However, the shield method is facing more unprecedented technical challenges because of the increasingly complex conditions such as high water pressure and mixed ground formation. Shield tail seal plays an important role in the tunneling process, which is greatly affected by high water pressure, soil pressure or other factors that might endanger the construction safety. The injection of grease is of fundamental importance for shield tail seal, which can prevent water and soil from flowing into the shield machine. As a result, the sealed grease must be studied in details. This paper introduces an experiment on shield tail grease used in tunneling. The experiment includes testing in static pressure and propelling state, which can fully reflect the performance of shield tail grease in shield tunneling. The pressure change of grease during pipeline transportation and in the shield tail gap are both studied in this paper. The research results of this paper provide the technical reference for the safety control of shield tail seal during the tunneling process.

Published
2019
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8. Cyclic oxidation of Ti3AlC2 at 1000–1300°C in air

Author

Xiao Dong He, D.L. Xu, Yue Sun, Xukun Qian, Yao Li, and H. Li

Subjects
Materials science, Parabolic law, Scanning electron microscope, General Chemical Engineering, Mineralogy, General Chemistry, Temperature cycling, Substrate (electronics), Corrosion, Chemical engineering, Rutile, General Materials Science, Adhesive, Layer (electronics)
Abstract

The cyclic-oxidation behavior of Ti 3 AlC 2 was investigated at 1000–1300 °C in air for up 40 cycles. It was revealed that Ti 3 AlC 2 had excellent resistance to thermal cycling. The cyclic oxidation of Ti 3 AlC 2 basically obeyed a parabolic law. In all cases, the scales were dense, resistant to spalling and highly stratified. The inner continuous α-Al 2 O 3 layer was well adhesive, while the outermost layer changed from rutile TiO 2 at temperatures below 1100 °C to Al 2 TiO 5 at 1200 and 1300 °C, respectively. At 1300 °C, a mechanical-keying structure of inner Al 2 O 3 to the Ti 3 AlC 2 substrate formed, which improved the resistance to scale-spallation.

Published
2011
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9. Alkali-Activated Fly Ash Manufactured with Multi-stage Microwave Curing

Author

H. Li, Pam Basheer, Yun Bai, Matthias Fabian, Tong Sun, D.L. Xu, Kenneth T. V. Grattan, and S. Shi

Subjects
Portland cement, Compressive strength, Materials science, law, Fly ash, Microwave oven, TJ, Cementitious, Composite material, Microstructure, Curing (chemistry), Microwave, law.invention
Abstract

Alkali-activated fly ash (AAFA) manufactured with conventional thermal curing (85oC) shows comparative mechanical properties to Portland cement (PC) based system, demonstrating its potential as a future low-carbon and environmentally friendly alternative cementitious material. However, the environmental benefit which could have been achieved from the low carbon nature of AAFA is often offset by the higher energy consumption from thermal curing. Since microwave heating is usually considered as a low-energy and low-carbon heating method, some pilot attempts have been made in the literature to cure AAFA with domestic microwave ovens. However, due to the lack of control on the temperature and humidity in domestic microwave ovens, splashing of fresh AAFA pastes and microcracks of hardened AAFA are two main reasons causing the unsatisfactory performance of microwave cured AAFA.\ud \ud In this study, a custom-made microwave oven equipped with proportional-integral-derivative (PID) control was employed to cure AAFA samples. The microwave power was automatically regulated through the real-time temperature feedback from the fibre Bragg grating (FBG) sensor embedded in the AAFA sample. The microwave curing regime consisted of four curing stages at four different temperatures, namely 65oC, 85oC, 105oC and 125oC. The similar temperature profile was applied on the AAFA cured in a conventional thermal oven. Compressive strength, reaction products and microstructure of AAFA samples with two curing methods were examined by the analytical techniques of XRD, FTIR, NMR, MIP and SEM respectively. The results showed that AAFA under microwave curing exhibited higher compressive strength with less energy consumption than that under the conventional thermal curing. The microwave curing favoured the formation of Al-rich N-A-S-H gel in AAFA and a more compacted microstructure

Published
2016
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11. Multi-Asset Class Portfolio Optimisation Using a Belief Rule-Based System

Author

J.B. Yang, Daoning Zhang, D.L. Xu, Ser-Huang Poon, Yu-Wang Chen, and Simon Acomb

Subjects
Scheme (programming language), Engineering, business.industry, Evidential reasoning approach, Inference, Rule-based system, Asset (computer security), Class (biology), RiskMetrics, Portfolio, Artificial intelligence, business, computer, computer.programming_language
Abstract

The purpose of this paper is to apply a belief rule-based (BRB) system to solve the multi-asset class portfolio optimisation problems. The BRB system, was developed on the basis of the concept of belief structures and the evidential reasoning (ER) approach, is a generic non-linear modelling and inference scheme. In this paper, the procedures of implementing the BRB system with RiskMetrics WealthBench to portfolio optimisation are discussed in details. Two different ways are proposed to locate the optimal portfolios under constraints supplied by the investors. Numerical studies demonstrate the effectiveness and efficiency of the proposed methodology.

Published
2010
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12. Elastic Waves Propagating in a Laminated Cylinder Subjected to a Point Load

Author

D.L. Xu and X. Han

Subjects
Materials science, business.industry, Modal analysis, Structural engineering, Mechanics, Displacement (vector), Finite element method, Cylinder (engine), law.invention, symbols.namesake, Fourier transform, law, symbols, Point (geometry), Hamilton's principle, business, Dynamic equilibrium
Abstract

A computational method is proposed for analyzing transient waves in a laminated cylinder excited by impact point loads. This method combines the finite element method and the Fourier transform. The cylinder is divided into layer elements with three-nodal-lines along the wall thickness. The Hamilton principle is used to develop approximate dynamic equilibrium equations. The displacement response is determined by employing the Fourier transformation and the modal analysis. As examples, the displacement responses of laminated cylinders excited by point loads are calculated. The destribution of displacement response of the laminated cylinder is demonstrated clearly.

Published
2001
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