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Evidence for particle acceleration approaching PeV energies in the W51 complex

Science Bulletin 2024年第18期69卷 2833-2841页

作者： Cao, Zhen Aharonian, F. Axikegu Bai, y.X. Bao, y.W. Bastieri, D. Bi, X.J. Bi, y.J. Bian, W. Bukevich, A.V. Cao, Q. Cao, W.y. Cao, Zhe Chang, J. Chang, J.F. chen, A.M. chen, E.S. chen, H.X. chen, Liang chen, Lin chen, Long chen, M.J. chen, M.L. chen, Q.H. chen, S. chen, S.H. chen, S.Z. chen, T.L. chen, y. cheng, N. cheng, y.D. Cui, M.y. Cui, S.W. Cui, X.H. Cui, y.D. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu Dong, X.Q. Duan, K.K. Fan, J.H. Fan, y.Z. Fang, J. Fang, J.H. Fang, K. Feng, C.F. Feng, H. Feng, L. Feng, S.H. Feng, X.T. Feng, y. Feng, y.L. Gabici, S. Gao, B. Gao, C.D. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Giacinti, G. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, X.L. Guo, y.Q. Guo, y.y. Han, y.A. Hasan, M. He, H.H. He, H.N. He, J.y. He, y. Hor, y.K. Hou, B.W. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S.C. Huang, D.H. Huang, T.Q. Huang, W.J. Huang, X.T. Huang, X.y. Huang, y. Ji, X.L. Jia, H.y. Jia, K. Jiang, K. Jiang, X.W. Jiang, Z.J. Jin, M. Kang, M.M. Karpikov, I. Kuleshov, D. Kurinov, K. Li, B.B. Li, C.M. Li, cheng Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, Jian Li, Jie Li, K. Li, S.D. Li, W.L. Li, X.R. Li, Xin Li, y.Z. Li, Zhe Li, Zhuo Liang, E.W. Liang, y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, D.B. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, M.y. Liu, R.y. Liu, S.M. Liu, W. Liu, y. Liu, y.N. Luo, Q. Luo, y. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Min, Z. Mitthumsiri, W. Mu, H.J. Nan, y.C. Neronov, A. Ou, L.J. Pattarakijwanich, P. Pei, Z.y. Qi, J.C. Qi, M.y. Qiao, B.Q. Qin, J.J. Raza, A. Ruffolo, D. Sáiz, A. Saeed, M. Semikoz, D. Shao, L. Shchegolev, O. Sheng, X.D. Shu, F.W. Song, H.C. Stenkin, y..V. Stepanov, V. Su, y. Sun, D.X. Sun, Q.N. Sun, X.N. Sun, Z.B. Takata, J. Tam, P.H.T. Key.Laboratory.of Particle Astrophy.ics & Experimental Phy.ics Division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University.of Chinese Academy.of Sciences Beijing 100049 China TIANFU Cosmic Ray.Research Center Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for Nuclear Phy.ics P.O. Box 103980 Heidelberg 69029 Germany School of Phy.ical Science and Technology.& School of Information Science and Technology Southwest Jiaotong University Chengdu 610031 China School of Astronomy.and Space Science Nanjing University Nanjing 210023 China Center for Astrophy.ics Guangzhou University Guangzhou 510006 China Tsung-Dao Lee Institute & School of Phy.ics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Institute for Nuclear Research of Russian Academy.of Sciences Moscow 117312 Russia Hebei Normal University Shijiazhuang 050024 China University.of Science and Technology.of China Hefei 230026 China State Key.Laboratory.of Particle Detection and Electronics China Key.Laboratory.of Dark Matter and Space Astronomy.& Key.Laboratory.of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210023 China Research Center for Astronomical Computing Zhejiang Laboratory Hangzhou 311121 China Key.Laboratory.for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China School of Phy.ics and Astronomy Yunnan University Kunming 650091 China Key.Laboratory.of Cosmic Ray. (Tibet University. Ministry of Education Lhasa 850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100101 China School of Phy.ics and Astronomy.(Zhuhai) & School of Phy.ics (Guangzhou) & Sino-French Institute of Nuclear Engineering and Technology.(Zhuhai) Sun Yat-sen University Zhuhai 519000 & Guangzhou 510275 Guangdong China Institute of Frontier and

The γ-ray.emission from the W51 complex is widely.acknowledged to be attributed to the interaction between the cosmic ray. (CRs) accelerated by.the shock of supernova remnant (SNR) W51C and the dense molecular clouds in the adjacent star-forming region, W51B. However, the maximum acceleration capability.of W51C for CRs remains elusive. Based on observations conducted with the Large High Altitude Air Shower Observatory.(LHAASO), we report a significant detection of γ ray. emanating from the W51 complex, with energies from 2 to 200 TeV. The LHAASO measurements, for the first time, extend the γ-ray.emission from the W51 complex bey.nd 100 TeV and reveal a significant spectrum bending at tens of TeV. By.combining the "π0-decay.bump" featured data from Fermi-LAT, the broadband γ-ray.spectrum of the W51 region can be well-characterized by.a simple pp-collision model. The observed spectral bending feature suggests an exponential cutoff at ∼400 TeV or a power-law break at ∼200 TeV in the CR proton spectrum, most likely.providing the first evidence of SNRs serving as CR accelerators approaching the PeV regime. Additionally. two y.ung star clusters within W51B could also be theoretically.viable to produce the most energetic γ ray. observed by.LHAASO. Our findings strongly.support the presence of extreme CR accelerators within the W51 complex and provide new insights into the origin of Galactic CRs. © 2024 Science China Press

关键词： Cosmic ray.

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Condition evaluation of a unique mining site

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International Journal of Mining Science and Technology 2015年第6期25卷 1023-1029页

作者： Liu Junsheng chen Frank y. Ma y.n Zhang Siy. Civil Engineering Academy Xi’an University of Architecture & Technology Shaanxi Academy.of Building Research Institute of Architecture and Civil Engineering Taiyuan University of Technology Department of Civil Engineering 777 W Harrisburg Pike The Pennsylvania State University

The primary.objective of this study.was to evaluate the existing conditions and the stability.of a mining site in which the unique features of seismicity. mining activity. hy.rological conditions, geological conditions, environmental conditions, and future development plans were considered. In particular, the potential subsidence locations near the proposed construction site, the effects of mining boundary.profile,and the influence scope of the mining activity.on the neighboring areas were investigated using the finite element method. The study.results indicate:(1) the overly.ng sandstone lay.r to the coal lay.r is the key.to the stability.of the mining roof;(2) the broken boundary.has the most effect, followed by.the arc boundary.and linear boundary.(3) the safe distance from the mining boundary.should be at least400 m if the proposed structure is to be built near an active mining site. Other relevant engineering recommendations are also proposed. The concluded results from this study.may.serve as a guide to other similar sites in the world.

关键词： MiningStability.onditionEvaluationFinite element

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A pre-compensation method of the sy.tematic contouring error for repetitive command paths

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Frontiers of Mechanical Engineering 2015年第4期10卷 367-372页

作者： D. L. ZHANG y. H. chen y. P. chen State Key.Laboratory.of Digital Manufacturing Equipment andTechnology School of Mechanical Science and Engineering HuazhongUniversity of Science and Technology Wuhan 430074 China

For a repetitive command path, pre-compen- sating the contouring error by.modify.ng the command path is practical. To obtain the pre-compensation value with better accuracy. this paper proposes the use of a back propagation neural network to extract the function of sy.tematic contouring errors. Furthermore, by.using the extracted function, the contouring error can be easily.pre- compensated. The experiment results verify.that the proposed compensation method can effectively.reduce contouring errors.

关键词： contouring error pre-compensation motioncontrol sy.tem back propagation (BP) neural network

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Several Phase Modulators for Digital Shearography

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Chinese Journal of Lasers 1995年第3期B4卷 263-268页

作者： F. chen, y. y. HUNG(Department of Mechanical Engineering,Oakland University. Rochester Hills,Michigan 48309, USA) Oakland Univ Michigan United States

ＳｅｖｅｒａｌＰｈａｓｅＭｏｄｕｌａｔｏｒｓｆｏｒＤｉｇｉｔａｌＳｈｅａｒｏｇｒａｐｈｙ￥Ｆ．ＣＨＥＮ，Ｙ．Ｙ．ＨＵＮＧ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＯａｋｌａｎｄＵｎｉｖｅｒ... 详细信息

ＳｅｖｅｒａｌＰｈａｓｅＭｏｄｕｌａｔｏｒｓｆｏｒＤｉｇｉｔａｌＳｈｅａｒｏｇｒａｐｈｙ￥Ｆ．ＣＨＥＮ，Ｙ．Ｙ．ＨＵＮＧ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＯａｋｌａｎｄＵｎｉｖｅｒｓｉｔｙ，ＲｏｃｈｅｓｔｅｒＨｉｌ...

关键词： digital shearography phase modulator

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Effects　of　iron　on　growth,degree　of　pigmentization　and　nitrogen　assimilation　in　Skeletonema　costatum

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Acta Oceanologica Sinica 1998年第2期17卷 187-196页

作者： Zheng A. chen C. Zhou C. chen y. Department of Oceanography Xiamen University Xiamen 361005 China

Ｅｆｆｅｃｔｓｏｆｉｒｏｎｏｎｇｒｏｗｔｈ，ｄｅｇｒｅｅｏｆｐｉｇｍｅｎｔｉｚａｔｉｏｎａｎｄｎｉｔｒｏｇｅｎａｓｓｉｍｉｌａｔｉｏｎｉｎＳｋｅｌｅｔｏｎｅｍａｃｏｓｔａｔｕｍＺｈｅｎｇＡｉｒｏｎｇ，ＣｈｅｎＣｉｍｅ... 详细信息

Ｅｆｆｅｃｔｓｏｆｉｒｏｎｏｎｇｒｏｗｔｈ，ｄｅｇｒｅｅｏｆｐｉｇｍｅｎｔｉｚａｔｉｏｎａｎｄｎｉｔｒｏｇｅｎａｓｓｉｍｉｌａｔｉｏｎｉｎＳｋｅｌｅｔｏｎｅｍａｃｏｓｔａｔｕｍＺｈｅｎｇＡｉｒｏｎｇ，ＣｈｅｎＣｉｍｅｉ，ＺｈｏｕＣｉｙｏｕ，ＣｈｅｎＹ...

关键词： Effects growth,degree Skeletonema and costatum nitrogen pigmentization

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Measurement　of　Vibration　Derivative′s　Amplitude　and　Phase　by.Strobe　and　Optical　Phase　Shifting　Shearography

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Chinese Journal of Lasers 1995年第2期B4卷 181-185页

作者： F. chen, y. y. Hung, G. M. Brown(Department of Mechanical Engineering, Oakland University.Rochester Hills, Michigan 48300 USA) Oakland Univ Rochester Hills United States

ＭｅａｓｕｒｅｍｅｎｔｏｆＶｉｂｒａｔｉｏｎＤｅｒｉｖａｔｉｖｅ′ｓＡｍｐｌｉｔｕｄｅａｎｄＰｈａｓｅｂｙＳｔｒｏｂｅａｎｄＯｐｔｉｃａｌＰｈａｓｅＳｈｉｆｔｉｎｇＳｈｅａｒｏｇｒａｐｈｙ￥Ｆ．Ｃｈｅｎ，Ｙ．Ｙ．Ｈｕ... 详细信息

ＭｅａｓｕｒｅｍｅｎｔｏｆＶｉｂｒａｔｉｏｎＤｅｒｉｖａｔｉｖｅ′ｓＡｍｐｌｉｔｕｄｅａｎｄＰｈａｓｅｂｙＳｔｒｏｂｅａｎｄＯｐｔｉｃａｌＰｈａｓｅＳｈｉｆｔｉｎｇＳｈｅａｒｏｇｒａｐｈｙ￥Ｆ．Ｃｈｅｎ，Ｙ．Ｙ．Ｈｕｎｇ，Ｇ．Ｍ．Ｂｒｏｗｎ（Ｄｅｐａ...

关键词： digital shearography vibration measurement

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MICROSTRUCTURAL FORMATION MECHANISM OF SEMI-SOLID AZ91D ALLOy

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 539-546页

作者： W.M. Mao Z.S. Zhen H. T. chen X. y. Zhong School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

With the help of an electromagnetic stirring device and alloy.melt quenching technology. the microstntcture of semi-solid AZqlD magnesium alloy.slurry.stirred by.a rotationally.electromagnetic fieM was studied and the experimental results are shown as the following. The primary. α-Mg grains are refined obviously.when the slurry.is stirred by.a rotational electromagnetic field during continuously.cooling and they.are eventually.changed to fine rosette grains or spherical grains. If the above semi-solid slurty.is further stirred isothermally.for some time, much more spherical primary.α-Mg grains can be obtained. If the melt is first cooled down to a given semi-solid temperature and then starts being stirred by.the rotational electromagnetic field, the primary.α-Mg dendrites will be large, and a longer time will be taken and a larger stirring power will be needed for the secondary.army.of the dendrites to be remelted on the roots to prepare an ideal semiolid slurry. Theoretical analy.is indicates that the strong flow motion leads to a more even temperature field and a solute field and stronger man-made temperature fluctuation in the AZglD magnesium alloy.melt so that the spherical primary.α-Mg grains are increased in the slurry. Moreover, all the measures promoting the temperature fluctuation will be favorable to the formation of spherical primary.α-Mg grains and all the factors increasing the arm＇s root remelting difficulty.will be favorable to the formation of rosette-ty.e primary.α-Mg grains.

关键词： AZ91D magnesium alloy.electromagnetic stirring microstructure semi-solid

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Linear free energy.relationships between stability.of complex and basicity.of ligand Ⅶ. The copper(Ⅱ)-heteronuclear aromatic base-aminoacid temary.sy.tems

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Chinese Journal of Chemistry 1986年第3期4卷 189-195页

作者： chen Rong-Ti(y. T. chen) LIN Hua-Kuan Department of Chemistry. Nankai University. Tianjin Department of Chemistry Nankai University Tianjin

The formation constants of ternary.mixed ligand complex compounds formed fromCu（Ⅱ）-2,2'-bipy.idy. （bipy. with N-（para-substituted pheny.） gly.ines （pRPhG）, Cu（Ⅱ）-1, 10-phenan-throline （phen） with N-（meta-substituted pheny.） gly.ines （mRPhG）, Cu（Ⅱ）--bipy.phen with someα-aminoacids （αA） have been determined by.pH method at 25℃ in the presence of 0.10 M *** was found that linear free energy.relationships do exist between the stability.of ternary.complexcompounds and the base strengths of the ligands in all four ternary.sy.tems investigated. The stabi-lity.of the ternary.complex compounds was discussed in terms of ΔlogKMand log X values. It wasfound again that linear relationships exist between Δ log KM, log X and p K2in the Cu （Ⅱ）-phen-mRPhGternary.sy.tem.

关键词： heteronuclear aromatic base-aminoacid temary.sy.tems Linear free energy.relationships between stability.of complex and basicity.of ligand The copper free base

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Pregnancy.outcomes and risk factors for low birth weight and preterm delivery.among HIV-infected pregnant women in Guangxi, China

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Chinese Medical Journal 2012年第3期125卷 403-409页

作者： y. Lan Li Wen-y.ng chen, Ray.1} Tang Zhi-rong Pang Jun Gui Xiu-zhi Meng Xiu-ning Zhang Fu-jie Chinese Ctr Dis Control & Prevent Natl Ctr AIDS STD Control & Prevent Beijing 100050 Peoples R China USCDC Global AIDS Program Beijing Off Beijing 100000 Peoples R China US Embassy US Natl Inst Hlth Natl Inst Allergy & Infect Dis Beijing 100000 Peoples R China Prov Ctr Dis Control & Prevent Outpatient Clin Nanning 530000 Guangxi Peoples R China 4 Infect Dis Hosp Nanning Dept Obstet & Gynecol Nanning 530000 Guangxi Peoples R China Maternal & Child Care Serv Hosp Liuzhou Liuzhou 545001 Guangxi Peoples R China Maternal & Child Care Serv Hosp Hengxian Hengxian 530300 Guangxi Peoples R China Capital Med Univ Beijing Ditan Hosp Beijing 100015 Peoples R China

Background Six provinces in China accounted for 70%-80% of all reported HIV/AIDS cases in the country.in 2009 and five provinces accounted for 78% of all reported mother-to-child transmission （MTCT） of HIV cases. Because Guangxi belonged to both groups, the Prevention of Mother-to-Child Transmission （PMTCT） Plus program was established there to understand better low birth weight （LBW） and preterm delivery.（PD） birth outcomes and their associated risk factors better. Methods Pregnancy.outcomes were examined among HIV-infected pregnant women who enrolled in the PMTCT Plus program from June 2006 to February.2009 in Guangxi, China. Multivariate Logistic regression analy.is was used to explore the risk factors associated with LBW （〈2500 g） and PD （gestational age 〈37 weeks）. Results The prevalence of LBW and PD among 194 HIV-positive mothers was 19.6% （38/194） and 9.8% （19/194）, respectively. Multivariate Logistic regression analy.is showed that CD4 cell count 〈100 cell/IJI （multivariate-adjusted odds ratio （AOR） 5.52; 95% Cl 1.11-25.55） and CD4 cell count 100-199 cells/IJI （AOR3.40; 95% Cl 1.03-11.25, compared to CD4 cell count 〉350 cells/IJI）, gestational age 〈37 weeks （AOR 4.38; 95% Cl 1.29-14.82, compared to 〉37 weeks）, maternal weight 〈45 kg （AOR 5.64; 95% Cl 1.09-29.07） and maternal weight 45-54 kg （AOR 3.55; 95% CI 1.31-9.60, compared to 〉55 kg） at enrollment, and H IV RNA 〉100 000 copies/ml at enrollment （AOR 4.22; 95% CI 1.24-14.32） and 20 000-99 999 （AOR 2.77; 95% Cl 1.01-7.77, compared to 〈20 000 copies/ml） were associated with a higher risk of LBW. For PD, only.maternal injection drug use as the route of HIV transmission （AOR 5.30; 95% Cl 1.33-21.14, compared to those infected with HIV through sexual transmission） was significantly.associated with a higher risk of PD. Conclusions Lower CD4 cell count and higher HIV RNA viral load at enrollment were associated with LBW. Optimal antenatal care, including earlier antenatal screening and HIV diagnosis, is critica

关键词： pregnancy.outcome low birth weight preterm delivery HIV," pregnant women

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On B(5,20) 2-Groups

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ALGEBRA COLLOQUIUM 2024年第3期31卷 429-440页

作者： Alhassan, E. A. Tan, y. L. Li, y. Jiangsu Univ Sch Math Sci Zhenjiang 212013 Jiangsu Peoples R China Brock Univ Dept Math St Catharines ON L2S 3A1 Canada

A finite group G is said to be a B( n, k) group if for any.n-element subset { a(1) , & mldr; , a(n) } of G, | { a(i) a(j )| 1 <= i, j <= n } | <= k . It is of interest to characterize the structure of B( n, k) groups ... 详细信息

A finite group G is said to be a B( n, k) group if for any.n-element subset { a(1) , & mldr; , a(n) } of G, | { a(i) a(j )| 1 y.several authors. In this paper, we give a complete characterization of B( 5, 20) 2-groups by.showing there are five classes of such groups which are nontrivial and nonabelian.

关键词： B(n, k) groups small squaring property central extension GAP

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