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Prospect of ultrahigh-resolution fast neutron absorption spectroscopy based on a laser plasma electron accelerator

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High Power Laser Science and Engineering 2024年第1期12卷 108-115页

作者： Wen-Zhao Wang Jie Feng Xiao-Peng Zhang yao-jun li Wei-jun Zhou Wen-Chao Yan Guo-Qiang Zhang Chang-Bo Fu li-Ming Chen Key Laboratory of Laser Plasma(MoE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghaiChina IFSA Collaborative Innovation Center Shanghai Jiao Tong UniversityShanghaiChina Institute of High Energy Physics Chinese Academy of SciencesBeijingChina Shanghai Advanced Research Institute Chinese Academy of SciencesShanghaiChina Key Laboratory of Nuclear Physics and Ion-beam Application(MoE) Institute of Modern PhysicsFudan UniversityShanghaiChina

Fast neutron absorption spectroscopy is widely used in the study of nuclear structure and element analysis. However,due to the traditional neutron source pulse duration being of the order of nanoseconds, it is difficult to obtain a high-resolution absorption spectrum. Thus, we present a method of ultrahigh energy-resolution absorption spectroscopy via a high repetition rate, picosecond duration pulsed neutron source driven by a terawatt laser. The technology of single neutron count is used, which results in easily distinguishing the width of approximately 20 keV at 2 MeV and an asymmetric shape of the neutron absorption peak. The absorption spectroscopy based on a laser neutron source has one order of magnitude higher energy-resolution power than the state-of-the-art traditional neutron sources, which could be of benefit for precisely measuring nuclear structure data.

关键词： fast neutron absorption spectroscopy laser plasma accelerator photo-nuclear neutrons single neutron count

Divergence angle consideration in energy spread measurement for high-quality relativistic electron beam in laser wakefield acceleration

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Chinese Physics B 2024年第6期33卷 363-368页

作者：卢光伟李曜均胡曦辰陈思宇徐豪祝铭阳闫文超陈黎明 Key Laboratory for Laser Plasmas of Ministry of Education Shanghai Jiao Tong UniversityShanghai 200240China IFSA Collaborative Innovation Center Shanghai Jiao Tong UniversityShanghai 200240China

The thorough exploration of the transverse quality represented by divergence angle has been lacking yet in the energy spread measurement of the relativistic electron beam for laser wakefield acceleration(LWFA). In this work, we fill this gap by numerical simulations based on the experimental data, which indicate that in a C-shape magnet, magnetic field possesses the beam focusing effect, considering that the divergence angle will result in an increase in the full width at half maxima(FWHM) of the electron density distribution in a uniformly isotropic manner, while the length-to-width ratio decreases. This indicates that the energy spread obtained from the electron deflection distance is smaller than the actual value, regardless of the divergence angle. A promising and efficient way to accurately correct the value is presented by considering the divergence angle(for instance, for an electron beam with a length-to-width ratio of 1.12, the energy spread correct from 1.2% to 1.5%), providing a reference for developing the high-quality electron beam source.

关键词： relativistic electron beams acceleration by laser–plasma interactions finite element analysis

Investigation on the stall types in impellers with different blade numbers

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Journal of Hydrodynamics 2023年第2期35卷 299-313页

作者： Xiao-dong liu yao-jun li Zhu-qing liu Wei Yang College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China

Stall is a complex flow phenomenon and its existence usually shows significant differences in different impeller *** this paper,the flow field characteristics and mechanism of stall types in impellers with different blade numbers were studied through the combination of experiment and numerical simulation at stall inception *** the experiments,it was observed that the five-blade impeller entered the rotating stall stage from a relatively stable flow field within a small flow rate *** the six-blade impeller,the root cause that stall vortices appeared in channels alternately rather than each one evenly was also reasonably *** validated numerical simulation method was utilized to reveal the three-dimensional flow field in impeller *** results indicate the swirling vortex near the impeller shroud was periodically sucked in and escaped from region near the blade suction side,which was the fundamental driving force of rotating *** sudden change of flow field caused by the fusion of the separation vortex at the channel inlet and the vortex induced by the swirling vortex near shroud is the essential reason for the formation of alternating ***’s more,the stall inception flow field is clearly defined in impellers,which is of great significance for the further analysis of stall *** on the distribution characteristics of vortex structure near impeller shroud with different blade numbers at different flow rate conditions,this paper deeply investigated the formation mechanism of different stall types in impellers.

关键词： Numerical simulation high-frequency particle image velocimetry(PIV) impellers swirling vortex stall type

Galaxy properties derived with spectral energy distribution fitting in the Hawaii-Hubble Deep Field-North

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Research in Astronomy and Astrophysics 2019年第3期19卷 53-70页

作者： Fang-You Gao jun-yao li Yong-Quan Xue CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China School of Astronomy and Space Science University of Science and Technology of China

We compile multi-wavelength data from ultraviolet to infrared(IR) bands as well as redshift and source-type information, for a large sample of 178 341 sources in the Hawaii-Hubble Deep Field-North field. A total of 145 635 sources among the full sample are classified/treated as galaxies and have redshift information available. We derive physical properties for these sources utilizing the spectral energy distribution fitting code CIGALE that is based on Bayesian analysis. Through various consistency and robustness checks, we find that our stellar-mass and star-formation rate(SFR) estimates are reliable, which is mainly due to two facts. Firstly, we adopt the most up-to-date and accurate redshifts and point spread functionmatched photometry; and secondly, we make sensible parameter choices with the CIGALE code and take into account the influences of mid-IR/far-IR data, star-formation history models, and AGN contribution. We release our catalog of galaxy properties publicly(including, e.g., redshift, stellar mass, SFR, age, metallicity, dust attenuation). It is the largest of its kind in this field and should facilitate future relevant studies on the formation and evolution of galaxies.

关键词： catalogs-galaxies fundamental parameters-galaxies star formation

X-ray absorption and 9.7μm silicate feature as a probe of AGN torus structure

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Research in Astronomy and Astrophysics 2020年第9期20卷 268-276页

作者： jun Xu Mou-Yuan Sun Yong Quan Xue jun-yao li Zhi-Cheng He Department of Astronomy CAS Key Laboratory for Research in Galaxies and CosmologyUniversity of Science and Technology of ChinaHefei 230026China Department of Astronomy Xiamen UniversityXiamen 361005China

The dusty torus plays a vital role in unifying active galactic nuclei(AGNs).However,the physical structure of the torus remains largely *** we present a systematical investigation of the torus mid-infrared(MIR)spectroscopic feature,i.e.,the 9.7μm silicate line,of 175 AGNs selected from the Swift/BAT Spectroscopic Survey(BASS).Our sample is constructed to ensure that each of the 175 AGNs has Spizter/IRS MIR,optical,and X-ray spectroscopic ***,we can simultaneously measure the silicate strength,optical emission lines,and X-ray properties(e.g.,the column density and the intrinsic X-ray luminosity).We show that,consistent with previous works,the silicate strength is weakly correlated with the hydrogen column density(N_H^X),albeit with large *** X-ray unobscured AGNs,the silicate-strength-derived V-band extinction and the broad-Hα-inferred one are both small;however,for X-ray obscured AGNs,the former is much larger than the *** addition,we find that the optical type1 AGNs with strong X-ray absorption on average show significant silicate absorption,indicating that their X-ray absorption might not be caused by dust-free gas in the broad-line *** results suggest that the distribution and structure of the obscuring dusty torus are likely to be very *** test our results against the smooth and clumpy torus models and find evidence in favor of the clumpy torus model.

关键词： galaxies:active infrared:galaxies quasars:general

Study of the internal characteristics of the stall in a centrifugal pump with a cubic non-linear SGS model

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Journal of Hydrodynamics 2019年第4期31卷 788-799页

作者： Xian-bei Huang Zhu-qing liu yao-jun li Wei Yang Qiang Guo School of Hydraulic Energy and Power Engineering Yangzhou University Yangzhou 225127 China College of Water Resources and Civil Engineering China Agricultural University Beijing 100083 China

The stall in a centrifugal pump impeller under a quarter-load condition is investigated by using a third-order SGS model named the DCNM, for a better understanding of the rotation effect on the stall phenomenon. The study of the distributions of the Reynolds stresses, the production tei*m and the rotation term reveals that the production and the rotation jointly result in the non-uniform Reynolds stress distribution. Further study of the two components of the production and the rotation shows that they jointly transport a certain energy from the Reynolds component R、to Ruu.

关键词： Centrifligal pump large-eddy simulation non-linear model OpenFOAM stall

2型糖尿病伴泌汗神经功能紊乱患者胰岛素分泌和血清25(OH)D3、NLR、SUA水平及临床意义分析

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河北医科大学学报 2024年第5期45卷 580-584页

作者：席巍姚丽君汪琳姣江苏省海安市人民医院内分泌科江苏海安2266000

目的探讨2型糖尿病伴泌汗神经功能紊乱患者胰岛素分泌和血清25羟维生素D3[25 hydroxyvitamin D3,25(OH)D3]、中性粒细胞与淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)、血尿酸(serum uric acid,SUA)水平变化及临床意义。方法选... 详细信息

目的探讨2型糖尿病伴泌汗神经功能紊乱患者胰岛素分泌和血清25羟维生素D3[25 hydroxyvitamin D3,25(OH)D3]、中性粒细胞与淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)、血尿酸(serum uric acid,SUA)水平变化及临床意义。方法选取在我院治疗的2型糖尿病伴泌汗神经功能紊乱患者97例作为观察组,以性别配比1∶2选取2型糖尿病不伴泌汗神经功能紊乱患者194例作为对照组,分析比较2组临床资料、胰岛功能及25(OH)D3、NLR和SUA水平差异,通过Logistic回归分析分析2型糖尿病伴泌汗神经功能紊乱的影响因素。结果观察组年龄、糖尿病病程分别为(58.32±9.94)岁和(11.41±2.84)年,明显高于对照组(P<0.05);观察组糖负荷30 min净增C肽与葡萄糖比值(ΔC-P30/ΔG30)、净增胰岛素与葡萄糖比值(ΔI30/ΔG30)、胰岛素曲线下面积(I-AUC/G-AUC)和120 min血糖曲线下面积校正后的C肽(C-P-AUC/G-AUC)分别为(0.22±0.13)、(1.55±0.36)、(0.09±0.03)和(2.87±0.90),明显低于对照组(P<0.05)。观察组血清25(OH)D3为(22.12±6.01)μg/L,明显低于对照组(P<0.05),而NLR和SUA分别为(3.12±0.94)和(365.50±90.48)μmol/L,明显高于对照组(P<0.05)。Logistic回归分析显示:年龄、糖尿病病程、ΔC-P30/ΔG30、25(OH)D3、NLR和SUA是2型糖尿病伴泌汗神经功能紊乱的影响因素(P<0.05)。结论2型糖尿病伴泌汗神经功能紊乱患者胰岛素分泌功能受损,血清25(OH)D3降低,而NLR和SUA水平升高;2型糖尿病伴泌汗神经功能紊乱受早期相胰岛分泌功能以及血清25(OH)D3、NLR、SUA水平的影响,值得进一步研究。

关键词：糖尿病,2型胰岛素分泌泌汗神经功能紊乱

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Van der Pauw Hall Measurement on Intended Doped ZnO Films for p-Type Conductivity

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Chinese Physics Letters 2010年第6期27卷 171-174页

作者： GUO Yang liU yao-Ping li jun-Qiang ZHANG Sheng-li MEI Zeng-Xia DU Xiao-Long Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190

A Van der Pauw Hall measurement is performed on the intended doped ZnO films （Na doped ZnO） grown by using the molecular beam epitaxial method. All as-grown samples show n-type conductivity, whereas the annealed samples （annealing temperature 900℃） show ambiguous carrier conductivity type （n- and p-type） in the automatic Van der Pauw Hall measurement. A similar result has been observed in li doped ZnO and in as-doped ZnO films by other groups before. However, by tracing the Hall voltage in the Van der Pauw Hall measurement, it is found that this alternative appearance of both n- and p-type conductivity is not intrinsic behavior of the intended doped ZnO films, but is due to the persistent photoconductivity effect in ZnO. The persistent photoconductivity effect would strongly affect the accurate determination of the carrier conductivity type of a highly resistive intended doped ZnO sample.

关键词： HALL effect ZINC oxide thin films MOLECULAR beam epitaxy CRYSTAL growth ANNEAliNG of crystals TEMPERATURE effect PHOTOCONDUCTIVITY

Design, Synthesis and Biological Evaluation of Non-azole Inhibitors of Lanosterol 14α-Demethylase of Fungi

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Chinese Chemical Letters 2006年第9期17卷 1189-1192页

作者： Bin yao You jun ZHOU Jü ZHU Jia Guo Lü yao Wu li jun CHENG Qing Feng JIANG Can Hui ZHENG School of Pharmacy Second Military Medicial University Shanghai 200433

Novel tetralin compounds were designed and synthesized on the three-dimensional model of lanosterol 14α-demethylase of Candida albicans. All of the lead compounds exhibited potent antifungal activities, especially compounds 16, 20. The mode of the action of the lead compounds was different from that of azoles. The present study affords the possibility to develop novel antifungal agents that specifically interact with the amino acid residues in the active site and avoid the serious toxicity arising from coordination binding with the heme of mammalian P450s.

关键词： Antifungal 2-aminotetralins lanosterol 14α-demethylase inhibitor.