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First Digit Distributions of Gamma-Ray Bursts

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Research in Astronomy and Astrophysics 2024年第5期24卷 70-75页

作者： Hou-Yu Lai jun-jie w.i Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

The occurrence of the first significant digits from real world sources is usually not equally distributed,but is consistent with a logarithmic distribution instead,known as Benford’s *** this work,we perform a comprehensive investigation on the first digit distributions of the duration,fluence,and energy flux of gamma-ray bursts (GRBs) for the first *** a complete GRB sample detected by the Fermi satellite,we find that the first digits of the duration and fluence adhere to Benford’s ***,the energy flux shows a significant departure from this law,w.ich may be due to the fact that a considerable part of the energy flux measurements is restricted by lack of spectral *** on the conventional duration classification scheme,we also check if the durations and fluences of long and short GRBs (with duration T_(90)>2 s and T_(90)≤2 s,respectively) obey Benford’s *** find that the fluences of both long and short GRBs still agree with the Benford distribution,but their durations do not follow Benford’s *** results hint that the long–short GRB classification scheme does not directly represent the intrinsic physical classification scheme.

关键词： (stars:)gamma-ray burst general-methods statistical-astronomical databases miscellaneous

A Simple Proof of ACC for Minimal Log Discrepancies for Surfaces

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Acta Mathematica Sinica,English Series 2024年第2期40卷 425-434页

作者： Jing jun HAN Yu jie LUO Shanghai Center for Mathematical Sciences Fudan UniversityJiangwan CampusShanghai 200438P.R.China Department of Mathematics Johns Hopkins UniversityBaltimoreMD 21218USA

Following Shokurov's idea,we give a simple proof of the ACC conjecture for minimal log discrepancies for surfaces.

关键词： Ascending chain condition minimal log discrepancies minimal model program surface

Spectral Fittings of warm Coronal Radiation with High Seed Photon Temperature:Apparent Low-temperature and Flat Soft Excess in AGNs

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Research in Astronomy and Astrophysics 2024年第7期24卷 135-144页

作者： Ze-Yuan Tang jun-jie Feng jun-Hui Fan School of Mathematics and information Science Guangzhou UniversityGuangzhou 510006China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province Guangzhou 510006China Key Laboratory for Astronomical Observation and Technology of Guangzhou Guangzhou 510006China

A warm corona has been widely proposed to explain the soft excess(SE)in X-ray above the 2-10 ke V power law extrapolation in Active Galactic Nuclei(AGNs).in actual spectral fittings,the warm coronal seed photon temperature(T_s)is usually assumed to be far away from the soft X-ray,but kT_scan reach close to 0.1 ke V in the standard accretion disk *** this study,we used Monte Carlo simulations to obtain radiation spectra from a slab-like warm corona and fitted the spectra using the spherical-geometry-based routine THCOMP or a thermal *** findings reveal tha high T_scan influence the fitting results.A moderately high kT_s(around 0.03 ke V)can result in an apparent low-temperature and flat SE,w.ile an extremely high kT_s(around 0.07 ke V)can even produce an unobserved blackbody-like *** conclusions indicate that,for spectral fittings of the warm coronal radiation(SE in AGNs),kT_sshould be treated as a free parameter with an upper limit,and an accurate coronal geometry is necessary when kT_s>0.01 ke V.

关键词： galaxies active-accretion-accretion disks-black hole physics

Prediction models of burst strength degradation for casing with considerations of both wear and corrosion

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Petroleum Science 2024年第1期21卷 458-474页

作者： jie-Li wang wen-jun Huang De-Li Gao MOE Key Laboratory of Petroleum Engineering China University of PetroleumBeijing102249China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China

Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep *** paper aims to predict the casing burst strength with considerations of both wear and ***,the crescent wear shape is simplified into three categories according to common mathematical ***,based on the mechano-electrochemical(M-E)interaction,the prediction model of corrosion depth is built with worn depth as the initial condition,and the prediction models of burst strength of the worn casing and corroded casing are ***,the accuracy of different prediction models is validated by numerical simulation,and the main influence factors on casing strength are *** last,the theoretical models are applied to an ultra-deep well in Northwest China,and the dangerous well sections caused by wear and corrosion are predicted,and the corrosion rate threshold to ensure the safety of casing is *** results show that the existence of wear defects results in a stress concentration and enhanced M-E interaction on corrosion depth *** accuracy of different mathematical models is different:the slot ring model is most accurate for predicting corrosion depth,and the eccentric model is most accurate for predicting the burst strength of corroded *** burst strength of the casing will be overestimated by more than one-third if the M-E interaction is neglected,so the coupling effect of wear and corrosion should be sufficiently considered in casing integrity evaluation.

关键词： Deep well Casing integrity Casing wear Casing corrosion Burst strength

An approach for determination of lateral limit angle in kinematic planar sliding analysis for rock slopes

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1305-1314页

作者： Xiaojuan Yang jie Hu Honglei Sun jun Zheng College of Civil Engineering Zhejiang University of TechnologyHangzhou310023China Department of Civil Engineering Zhejiang UniversityHangzhou310058China Center for Balance Architecture Zhejiang UniversityHangzhou310007China The Architectural Design & Research institute of Zhejiang University Co. Ltd.Hangzhou310063China

Planar sliding is one of the frequently observed types of failure in rock *** analysis is a classic and widely used method to examine the potential failure modes in rock *** accuracy of planar sliding kinematic analysis is significantly influenced by the value assigned to the lateral limit angleγ***,the assignment ofγlim is currently used generally based on an empirical *** study aims to propose an approach for determining the value ofγlim in deterministic and probabilistic kinematic planar sliding analysis.A new perspective is presented to reveal thatγlim essentially influences the probability of forming a potential planar sliding *** procedure to calculate this probability is introduced using the block theory *** is found that the probability is correlated with the number of discontinuity sets presented in rock ***,different values ofγlim for rock masses with different sets of discontinuities are recommended in both probabilistic and deterministic planar sliding kinematic analyses;whereas a fixed value ofγlim is commonly assigned to different types of rock masses in traditional ***,an engineering case was used to compare the proposed and traditional kinematic analysis *** error rates of the traditional method vary from 45%to 119%,w.ile that of the proposed method ranges between 1%and 17%.Therefore,it is likely that the proposed method is superior to the traditional one.

关键词： Kinematic analysis Block theory Planar sliding Lateral limit angle Rock slope

Sequential enantioselective Ugi-4CR/post-Ugi transformation strategy:a precise construction of structurally diverse azaspiro polycyclic scaffolds

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Science China Chemistry 2024年第2期67卷 576-586页

作者： Xiao-Bao wu jun-Xiu Shi Yi-Ming Ou Hua-jie Jiang Yi-jun Fang Qi-Ming wang Quan Gao jie Yu Department of Applied Chemistry Anhui Province Engineering Laboratory for Green Pesticide Development and ApplicationAnhui Province Key Laboratory of Crop Integrated Pest ManagementAnhui Agricultural UniversityHefei230036China

A privileged strategy has been developed for the precise construction of enantioenriched azaspiro polycyclic *** diverse azaspiro polycycles bearing multiple contiguous stereocenters are obtained with excellent results(up to 99:1 e.r.,>95:5 d.r.) via sequential enantioselective four-component Ugi reactions/post-Ugi transformations with substrates containing prerequisite functional groups in the presence of anionic stereogenic-at-cobalt(Ⅲ) complexes.

关键词： asymmetric catalysis post-Ugi transformation anionic stereogenic-at-cobalt(Ⅲ)complex azaspiro polycyclic scaffold one-pot synthesis

Four-birds-with-one-stone:A multifunctional Ti-based material for solar-driven water evaporation

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Nano Research 2024年第5期17卷 4498-4506页

作者： Yannan Li Yaning Sun Dan Zhang Yu Xue jie wang Nan Zhang jun wang Jiangw.i Zhang Yan Zhao jun-jie Liu School of Physical Science and Technology College of Energy Materials and ChemistryInner Mongolia UniversityHohhot 010021China

Sustainable,environmentally friendly and low-energy desalination materials have important research value for the increasing demand of freshwater year by ***,it is a huge challenge to maintain high heat energy transfer efficiency without reducing the heat conversion capacity of specific solar photothermal conversion ***,their efficiency and durability are greatly limited by the problems of seawater corrosion,oil,and bacteria *** now,no related work has been reported to solve all the aforementioned problems via a simple four-birds-with-one-stone ***,a class of multifunctional porous photothermal silver(Ag)modified Ti foams(Tf-TA/Ag series materials)is prepared for the development of advanced solar water evaporation devices,and provides alternative materials for alleviating freshwater crisis and treating *** oil contact angle(OCA)changes from 41°to 180°,w.ich significantly reduces the adhesion of *** addition,Tf-TA2/Ag sample also shows an excellent and sustained antibacterial effect,w.ich maintains above 99.9%of antibacterial rate after repeated 5 *** surface temperature of the Tf-TA2/Ag sample reaches 52.5℃ after simulated sun irradiation for 20 min,w.ich is significantly higher than that of the contact groups(water:36.4℃,Ti foam:38.2℃ and Tf-TA2:40.9℃).The capacity of seawater evaporation and salt removal is enhanced due to the excellent photothermal properties,low reflectance,and uniform heat dissipation *** water production efficiency of Tf-TA2/Ag sample is 1.41 kg·m^(-2)·h^(-1) in artificial seawater and 0.76 kg·m^(-2)·h^(-1) in oily sewage under simulated sun ***,the hydrophilic and oleophobic properties of Tf-TA2/Ag are critical to extracting water from oil/water mixture in diverse water ***,this four-birds-with-one-stone approach provides a new perspective for the improvement of solar seawater desalination performance.

关键词： four-birds-with-one-stone photothermal material antibacterial material antifouling property

Possible Habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in the initial Conditions of High-mass Star Formation

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Research in Astronomy and Astrophysics 2024年第4期24卷 237-252页

作者： Quan-Ling Cui Chuan-Peng Zhang jun-jie wang National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Science Qiqihar UniversityQiqihar 161006China Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China

The initial condition of high-mass star formation is a complex area of study because of the high densities(n_(H_(2))>106cm^(-3))and low temperatures(T_(dust)<18 K)*** such conditions,many molecules become depleted fro... 详细信息

The initial condition of high-mass star formation is a complex area of study because of the high densities(n_(H_(2))>106cm^(-3))and low temperatures(T_(dust)itions,many molecules become depleted from the gas phase by freezing out onto dust ***,the N-bearing and deuterated species could remain gaseous under these extreme conditions,suggesting that they may serve as ideal *** this paper,using the Plateau de Bure interferometer and Very Large Array observations at 1.3 mm,3.5 mm,and 1.3 cm,we investigate the possible habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in eight massive precluster and protocluster clumps G18.17,G18.21,G23.97N,G23.98,G23.44,G23.97S,G25.38,and *** found that the NH3cores are in good agreement with the 3.5 mm peak emission,but the NH_(3)is much more extended than the 3.5 mm emission *** SO distributions agree well with the 3.5 mm peaks for the evolved star formation stage,but we did not detect any SO emission in the four earliest star formation sources.C^(18)O is a poor tracer in conditions of the cold(■18 K)and dense(■10^(4)cm^(-3))cores,e.g.,the prestellar *** also found that the NH_(2)D cores are mainly located in the temperature range of 13.0-20.0 K,and the NH_(2)D lines may be strongly depleted above 20 K.

关键词： galaxies:star formation techniques:interferometric methods:observational

Multiwavelength Observations of the infrared Dust Bubble N75 and its Surroundings

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Research in Astronomy and Astrophysics 2024年第4期24卷 262-270页

infrared dust bubbles play an important role in the study of star formation and the evolution of the interstellar *** this work,we study the infrared dust bubble N75 and the infrared dark cloud G38.93 mainly using the tracers C^(18)O,HCO^(+),HNC and N_(2)H^(+)observed by the 30 m iRAM *** also study the targets using data from large-scale surveys:GLiMPSE,MiPSGAL,GRS,NRAO VLA Sky Survey and Bolocam Galactic Plane *** found that the C^(18)O emission is morphologically similar to the Spitzer iRAC 8.0μm ***1.1 mm cold dust emission of G38.93 shows an elongated structure from southwest to *** ionized gas from G38.93 is surrounded by polycyclic aromatic hydrocarbon emission,w.ich may be excited by radiation from *** found that the identified young stellar objects tend to cluster around G38.93 and are mostly in class ii with several class i cases distributed around N75,but no class ii *** also found evidence of expanding feedback,w.ich could have triggered star formation.

关键词： iSM:bubbles infrared:iSM galaxies:star formation