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Multiband fitting to three long GRBs with Fermi/LAT data:structured ejecta sweeping up a density-jump medium

Research in Astronomy and Astrophysics 2011年第9期11卷 1046-1066页

作者： si-yi feng Zi-Gao Dai Department of Astronomy Nanjing University Nanjing 210093 China Key Laboratory of Modern Astronomy and Astrophysics （Nanjing University） Ministry of Education Nanjing 210093 China

We present broadband （radio, optical, X-ray and GeV） fits to the afterglow light curves and spectra of three long-duration gamma-ray bursts （GRBs 080916C, 090902B, and 090926A） detected by the Gamma-Ray Burst Monitor and Large Area Telescope （LAT） instruments on the Fermi satellite. Using the observed broadband data, we study the origin of the high energy emission, and suggest that the early-time GeV emission and the late-time radio, optical, and X-ray afterglows can be under- stood as being due to synchrotron emission from an external forward shock caused by structured ejecta propagating in a wind bubble jumping to a homogeneous density medium. If the ceasing time for a majority of the energy injection is assumed to be close to the deceleration time of the forward shock, the structured ejecta with con- tinuous energy injection towards the forward shock can well explain the early rising feature of the GeV mission from these bursts, and the density-jump medium can ac- count for some particular plateaus or flares in the late afterglows. From our fits, we find that, on one hand, the external shock origin of the GeV photons will make the optical depth not have a significant contribution to the early LAT rising part, which will loosen the strong constraint of lower limits of the Lorentz factor. On the other hand, these Fermi-LAT events preferentially occur in a low-density circumburst environment, in which case the Klein-Nishina cutoff will significantly suppress the Self- Synchrotron Compton radiation. Such an environment might result from superbubbles or low-metallicity progenitor stars （which have a low mass-loss rate at late times of stellar evolution） of type Ib/c supernovae.

关键词： gamma-rays: bursts -- gamma-rays: theory

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Photocatalytic oxidation of primary and secondary benzyl alcohol catalyzed by two coenzyme NAD^+ models

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Chinese Chemical Letters 2007年第12期18卷 1471-1475页

作者： Hua Jian Xu Xiao Lan Xu Yao Fu yi si feng School of Chemical Engineering HeFei University of Technology Hefei 230009 China Department of Chemistry AnHui Medical University Hefei 230032 China Department of Chemistry University of Science and Technology of China Hefei 230026 China

Photocatalytic oxidation of primary and secondary benzyl alcohol to corresponding benzaldehyde or acetophenone using Acr＋Cl04- or PhAcr＋Cl04- as photocatalysts under visible light irradiation at room temperature.

关键词： Photocatalyst Coenzyme NAD^+ model Benzyl alcohol Mechanism

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Characterization and reactivity of γ-Al2O3 supported Pd–Cu bimetallic nanocatalysts for the selective oxygenization of cyclopentene

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Chinese Chemical Letters 2016年第6期27卷 905-909页

作者： Wei-Wei Liu yi-si feng Guang-Yu Wang Wei-Wei Jiang Hua-Jian Xu School of Chemistry and Chemical Engineering School of Medical Engineering Hefei University of Technology Hefei 230009 China Anhui Key Laboratory of Controllable Chemical Reaction & Material Chemical Engineering Hefei 230009 China Anhui Provincial Laboratory of Heterocyclic Chemistry Maanshan 243110 China

In this work, Pd–Cu/γ-Al2O3 is prepared by the impregnation method and investigated for selective oxygenization of cyclopentene to cyclopentanone. A series of bimetallic Pd–Cu/γ-Al2O3 nanocatalysts were prepared and the structures characterized by XRD, XPS and TEM. We determined that the obtained Pd–Cu/γ-Al2O3（molar ratio Pd：Cu = 5：1） was an efficient catalyst for the oxygenization of cyclopentene to cyclopentanone with 95% selectivity and 85% conversion（100 °C, 1 MPa initial O2 pressure, 7 h）.

关键词： Impregnation method Oxygenization Cyclopentanone Cyclopentene Pd–Cu/γ-Al2O3

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Novel model combining contrast-enhanced ultrasound with serology predicts hepatocellular carcinoma recurrence after hepatectomy

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World Journal of Clinical Cases 2021年第24期9卷 7009-7021页

作者： Hai-Bin Tu Li-Hong Chen Yu-Jie Huang si-yi feng Jian-Ling Lin Yong-yi Zeng Department of Ultrasound Mengchao Hepatobiliary Hospital of Fujian Medical UniversityFuzhou 350025Fujian ProvinceChina Department of Hepatobiliary Surgery Mengchao Hepatobiliary Hospital of Fujian Medical UniversityFuzhou 350025Fujian ProvinceChina

BACKGROUND Surgery is the primary curative option in patients with hepatocellular carcinoma(HCC).However,recurrence within 2 years is observed in 30%–50%of patients,being a major cause of *** To construct and verify a non-invasive prediction model combining contrastenhanced ultrasound(CEUS)with serology biomarkers to predict the early recurrence of *** Records of 744 consecutive patients undergoing first-line curative surgery for HCC in one institution from 2016–2018 were reviewed,and 292 local patients were selected for *** characteristics including gender and age,CEUS liver imaging reporting and data system(LIRADS)parameters including wash-in time,wash-in type,wash-out time,and wash-out type,and serology biomarkers including alanine aminotransferase,aspartate aminotransferase,platelets,and alpha-fetoprotein(AFP)were *** analysis and multivariate Cox proportional hazards regression model were used to evaluate the independent prognostic factors for tumor *** a nomogram called CEUS model was *** CEUS model was then used to predict recurrence at 6 mo,12 mo,and 24 mo,the cut-off value was calculate by X-tile,and each C-index was *** Kaplan-Meier curve was compared by logrank *** calibration curves of each time were *** A nomogram predicting early recurrence(ER),named CEUS model,was formulated based on the results of the multivariate Cox regression *** nomogram incorporated tumor diameter,preoperative AFP level,and LIRADS,and the hazard ratio was 1.123(95%confidence interval[CI]:1.041-1.211),1.547(95%CI:1.245-1.922),and 1.428(95%CI:1.059-1.925),*** cut-off value at 6 mo,12 mo,and 24 mo was 100,80,and 50,and the C-index was 0.748(95%CI:0.683-0.813),0.762(95%CI:0.704-0.820),and 0.762(95%CI:0.706-0.819),*** model showed satisfactory results,and the calibration at 6 mo was desirable;however,the calibration at 12 and 24 mo should be improv

关键词： Hepatocellular carcinoma Recurrence Prediction Contrast-enhanced ultrasound Liver imaging reporting and data system Alpha-fetoprotein

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Characterization and reactivity of γ-Al_2O_3 supported Pd–Ni bimetallic nanocatalysts for selective hydrogenation of cyclopentadiene

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Chinese Chemical Letters 2015年第6期26卷 709-713页

作者： yi-si feng Jian Hao Wei-Wei Liu Yun-Jin Yao Yue Cheng Hua-Jian Xu School of Chemistry and Chemical Engineering School of Medical EngineeringHefei University of Technology Anhui Key Laboratory of Controllable Chemical Reaction & Material Chemical Engineering Anhui Provincial Laboratory of Heterocyclic Chemistry

Several γ-Al2O3 supported Pd-Ni bimetallic nanocatalysts （Pd-Ni （x：y）[Al2O3; where x and y represent the mass ratio of Pd and Ni, respectively） were prepared by the impregnation method and used for selective hydrogenation of cyclopentadiene to cyclopentene. The Pd-NiJAl2O3 samples were confirmed to generate Pd-Ni bimetallic nanoparticles by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and transmission electron microscopy （TEM）. The catalytic activity was assessed in view of the effects of different mass ratios of Pd and Ni, temperature, pressure, etc. Among all the samples, the Pd-Ni （1：1 ）/Al2O3 （PN-1：1 ） catalyst showed extremely high catalytic ability. The conversion of cyclopentadiene and selectivity for cyclopentene can be simultaneously more than 90%.

关键词： Impregnation method Hydrogenation Cyclopentadiene Cyclopentene Pd-Ni/Al2O3

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Covalent functionalization of graphene oxide by 9-(4-aminophenyl)acridine and its derivatives

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Chinese Chemical Letters 2012年第12期23卷 1411-1414页

作者： yi si feng Jing Jing Ma Xin Yan Lin Jia Song Zhang Peng Lv Hua Jian Xu Lin Bao Luo School of Chemical Engineering Hefei University of Technology School of Electronic Science & Applied Physics Hefei University of Technology School of Medical Engineering Hefei University of Technology

Graphene/acridine （G-Acr） hybrid structures were synthesized through covalent functionalization of graphene oxide with 9-（4- aminophenyl）acridine （APA） and its derivatives. The G-Act hybrids were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, thermal gravimetric analysis and Raman spectroscopy. X-ray photoelectron spectroscopy confirms that the binding energies of APA and its derivatives shifted to higher values, revealing pronounced charge transfer at the interface of graphene and organic molecules.

关键词： Graphene oxide Covalent functionalization Hybrid material Acridine derivative

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Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

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Tungsten 2025年第1期7卷 195-213页

作者： Zhi-Peng Zhu Dian Jia William yi Wang Jun-Lei yin Xing-Yu Gao Shu-feng Yang Hai-feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

关键词： First-principles calculations Phase stability TCP phases Thermodynamic properties W–Re alloy

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Spatiotemporal evolution of Ediacaran-Cambrian(ca. 551–523 Ma)sponges in South China and their simulated contributions to marine oxygenation

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Science China Earth Sciences 2025年

作者： Yan YE Lei ZHANG Can CHEN Shan CHANG Yuhao yi Qinglai feng State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(Wuhan) School of Earth Science China University of Geosciences(Wuhan) Department of Geology Lund University Institute of Sedimentary Geology Chengdu University of Technology Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of Technology Second Geological Brigade of Hubei Geological Bureau College of Urban and Environmental Sciences Hubei Normal University Exploration and Development Research Institute SINOPEC Jianghan Oilfield Company

The origin and evolution of sponges have attracted interest, not only because they are among the most basal metazoans, but also because they act as important ecological engineers in the ocean. Previous research suggested that sponge groups diversified quickly during the Cambrian Series 2, while Terreneuvian sponge fossils are conspicuously rare and poorly substantiated. Yet, an increasing number of sponge spicules have been reported from the Ediacaran-Cambrian(E-C, ca.551–523 Ma) transitional carbonates/cherts worldwide, particularly in South China, which calls for updated discussions. Ocean oxygenation has been widely proposed to play a critical role in organismal evolution, but its relationship with sponges is unclear and falls into a “chicken-egg” dilemma. In this study, we summarize reported sponge spicule distributions from five E-C sections in South China to investigate the early evolutionary pattern of siliceous sponges. According to current stratigraphic correlation,monaxons first appear in the late Ediacaran in the intrashelf basin-slope area, and then potentially expand to the continental shelf and deep basin in the lower Cambrian. In these sections, the abundance, size, and diversity of monaxons increase upwards,followed by the appearance of diaxons, triaxons and then polyactines. Despite the uncertain affinity of the sponge fossils, it is possible that siliceous hexactinellids evolved later than siliceous demosponges, given that the earliest spicule assemblages are exclusively composed of monaxons, which commonly form bundles comparable to modern demosponges. New geochemical data from the sifangjing section, Guizhou Province and the Yanziqiao section, Hunan Province, South China show that the appearance of sponges usually corresponds to anoxic environment. In addition, we applied the recently proposed Biological Pump, Oxygen and Phosphorus(BPOP) model to trace the evolution of oceanic oxygen concentrations with the radiation of sponges. The results indic

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Experimental demonstration of 220-GHz terahertz signals wireless transmission over 4.6 km

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Science China(Information Sciences) 2025年第1期68卷 386-388页

作者： yi WEI Jianjun YU Mingxu WANG Xiongwei YANG Qiutong ZHANG Jingwen TAN Bing ZHANG ying WU Yang HAN Peng TIAN Wen ZHOU Kaihui WANG feng ZHAO State Key Laboratory of AsiC and System Key Laboratory for Information Science of Electromagnetic Waves (MoE)School of Information Science and Technology Fudan University School of Electronic Engineering Xi'an University of Posts and Telecommunications

The advancement of terahertz (THz) communication technology drives the evolution of wireless communication systems,offering novel pathways and technical means for the development of future 6G communication *** wireless communication systems are often constrained by bandwidth limitations of electronic devices in high frequency ***,THz communication technology leverages the characteristics of electromagnetic waves to transcend these limitations,enabling communication athigher frequencies and wider bandwidths.

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Understanding the local structure and thermophysical behavior of Mg-La liquid alloys via machine learning potential

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 439-449页

作者： Jia Zhao Taixi feng Guimin Lu National Engineering Research Center for Integrated Utilization of Salt Lake Resource East China University of Science and TechnologyShanghai 200237China Joint International Laboratory for Potassium and Lithium Strategic Resources East China University of Science and TechnologyShanghai 200237China

The local structure and thermophysical behavior of Mg-La liquid alloys were in-depth understood using deep potential molecular dynamic(DPMD) simulation driven via machine learning to promote the development of Mg-La alloys. The robustness of the trained deep potential(DP) model was thoroughly evaluated through several aspects, including root-mean-square errors(RMSEs), energy and force data, and structural information comparison results;the results indicate the carefully trained DP model is reliable. The component and temperature dependence of the local structure in the Mg-La liquid alloy was analyzed. The effect of Mg content in the system on the first coordination shell of the atomic pairs is the same as that of temperature. The pre-peak demonstrated in the structure factor indicates the presence of a medium-range ordered structure in the Mg-La liquid alloy, which is particularly pronounced in the 80at% Mg system and disappears at elevated temperatures. The density, self-diffusion coefficient, and shear viscosity for the Mg-La liquid alloy were predicted via DPMD simulation, the evolution patterns with Mg content and temperature were subsequently discussed, and a database was established accordingly. Finally, the mixing enthalpy and elemental activity of the Mg-La liquid alloy at 1200 K were reliably evaluated,which provides new guidance for related studies.

关键词： magnesium-lanthanum liquid alloys local structure macroscopic properties thermodynamic behavior deep potential mo-lecular dynamic simulation

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