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Luminosity of a radio pulsar and its new emission death line

Research in Astronomy and Astrophysics 2020年第11期20卷 325-332页

作者： qing-dong wu Qi-Jun Zhi Cheng-Min Zhang De-Hua Wang Chang-qing Ye School of Physics and Electronic Sciences Guizhou Normal UniversityGuiyang 550001China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guiyang 550001China University of Chinese Academy of Sciences Beijing 100049China

We investigated the pulsar radio luminosity(L),emission efficiency(ratio of radio luminosity to its spin-down powerE),and death line in the magnetic field(B)versus spin period(P)*** found that the dependence of pulsar radio luminosity on its spin-down power(L-E)is very weak,shown as L^E0.06,which deduces an equivalent inverse correlation between emission efficiency and spin-down power asξ~***,we examined the distributions of radio luminosity of millisecond and normal pulsars and found that for the similar spin-down powers,the radio luminosity of millisecond pulsars is about one order of magnitude lower than that of the normal *** analysis of pulsar radio flux suggests that these correlations are not due to a selective effect but are intrinsic to the pulsar radio emission *** radio radiations may be dominated by the different radiation *** cutoff phenomenon of currently observed radio pulsars in B-P diagram is usually referred as the"pulsar death line",which corresponds toE≈1030 erg s-1 and is obtained by the cut-off voltage of electron acceleration gap in the polar cap model of pulsar proposed by Ruderman and ***,this death line can be inferred by the actual observed pulsar flux S≥1 mJy and 1 kpc distance,together with the maximum radio emission efficiency of 1%.However,the observation data show that the 37 pulsars pass over the death line,including the recently observed two pulsars with long periods of 23.5 s and 12.1 s,which violate the prediction of the polar cap *** present,the actual observed pulsar flux can reach0.01 mJy by FAST *** will arise the observational limit of spin-down power of pulsars as low as E˙≈1028 erg *** means that the new death line is downward shifted two orders of magnitude,which might be favorably referred as the"observational limit–line".Accordingly,the pulsar theoretical model for the cut-off voltage of gap should be heavily modified.

关键词： stars neutron pulsars general stars fundamental parameters

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β^--Decay Half-Lives for Waiting Point Nuclei Around N=126

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Communications in Theoretical Physics 2019年第3期71卷 293-297页

作者： Ji-Lin You qing-dong wu Xiao-Ping Zhang Qi-Jun Zhi School of Physics and Electronic Sciences Guizhou Normal University Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal University State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and Technology

We have systematically analyzed the experimental β--decay half-lives of waiting point heavy nuclei around neutron number N = 126. A new set of parameters for the exponential formula of β^--decay half-lives is proposed. The forbidden transition effects are included in the new set of parameters self-consistently. Theoretical β^--decay half-lives of nuclei around N = 126 are compared with recent theoretical results and experimental data. It is found that the new theoretical results are in better agreement with experimental data. The unknown β^--decay half-lives of some nuclei in this region are predicted for studies on nuclear structure far from stability and the nucleosynthesis in stars.

关键词： β^--decay half-lives waiting point nuclei nucleosynthesis

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Selective photosynthesis of imines from biomass-derived aldehydes over Ni/TiO_(2)

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Rare Metals 2024年第3期43卷 1116-1124页

作者： wu-Lin Li qing-qing Zhang Lin dong Wen-Jun Zhang Li-Li Lin Zu-Peng Chen Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjing210037China Institute of Industrial Catalysis State Key Laboratory of Green Chemistry Synthesis TechnologyCollege of Chemical EngineeringZhejiang University of TechnologyHangzhou310014China

Photocatalytic reductive amination of biomass-derived aldehydes is a desirable way to selectively upgrade biomass into value-added nitrogen-containing chemicals under mild ***,it is challenging to produce imines in high selectivity because of the undesirable side reactions caused by the activity of functional ***,we demonstrate the highly reactive and selective production of imines from biomass derived aldehydes via the photocatalytic reductive amination,using a defective TiO_(2)supported nickel *** employment of methanol as the hydrogen donor and ammonia solution as the nitrogen source avoids the use of high-pressure H_(2)and expensive amines,rendering the current catalytic process safe,economical,and environmentally *** depth investigations attribute the improved separation and transfer of photogenerated charge carriers to the presence of oxygen vacancies and decorated Ni nanoparticles,thereby accelerating the production of imines from benzaldehyde amination(conversion,95.8%;seleetivity,95.2%).Furthermore,the developed system could be easily translated to the photocatalytic conversions of various biomass derived aldehydes,which provided an example of a cost-effective and sustainable approach for the valorization of biomass derived feedstocks.

关键词： Photocatalysis Biomass derivatives Imines Reduction amination Heterogeneous catalyst

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The contribution of the first forbidden transitions to the nuclear β^--decay half-life

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Chinese Physics C 2019年第11期43卷 91-99页

作者： Ji-Lin You Xiao-Ping Zhang Qi-Jun Zhi Zhong-Zhou Ren qing-dong wu School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China School of Physics Science and Engineering Tongji UniversityShanghai 200092China

β-decay half-life is a key quantity for nuclear structure and nucleosynthesis *** exist large uncertainties in the contributions of allowed and forbidden transitions to the totalβ-decay life,which limits the resolution of the predictedβ-decay *** systematically study the contribution of the first forbidden(FF)transitions to theβ--decay half-life,and quantify it with a formula based on simple physics *** also propose a new formula for calculation of theβ--decay half-life that includes the FF *** is shown that the inclusion of the contribution of FF transitions significantly improves the precision of calculations of theβ--decay *** fitting of the RQRPA results for neutron-rich Z=47,57 isotopes and N=80,94 isotones,the formula for the contribution of the FF transitions gives similar results as the RQRPA ***,because of limited experimental data for the branching ratios of unstable nuclei,the fit parameters are not fully ***,the proposed formula for theβ--decay half-life is more suitable for calculations of half-lives than of the FF *** formula could be used to predict theβ?-decay half-life in nuclear structure studies as well as nucleosynthesis calculations in stars.

关键词： β^--decay half-life nucleosynthesis first forbidden transitions branching ratios

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An Organic Solvent-free Approach towards PDI/Carbon Cloth Composites as Flexible Lithium Ion Battery Cathodes

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高分子科学：英文版 2020年第5期38卷 540-549,I0008页

作者： dong-qing wu Deng Lu Peng Yang Lie Ma Biao Jiang Xin Xi Fan-Cheng Meng Wen-Bei Zhang Fan Zhang Qian-Qian Zhong Rui-Li Liu School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai200240China School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

An acidic solution based method towards flexible lithium ion battery(LIB)cathodes is developed in this work with perylene diimide(PDI)as the electroactive component and carbon cloth(CC)as the current *** this approach,PDI is firstly dispersed in concentrated sulfuric acid(H2S04)and then deposited on CC substrate after the dilution of H2S04,which provides an organic solvent-free strategy to construct integrated LIB *** acdic solution based fabrication process also allows the facile adjusting of loading amounts of PDI in the cathodes,which can effectively influence the battery performances of the PDI/CC *** the result,the acidic solution processed PDI/CC cathode can deliver a high specific capacity of-36 mAh·g^-1 at the current density of 50 mA·g^-1 in both half cell with lithium foil as anode and full cell with pre-lithiated CC as *** both types of the batteries,the PDI/CC cathodes show good cycling stabilities by retaining^84%of the initial capacities after 300 charge-discharge cycles at 500 mA·g^-***,the excellent mechanical stability of the PDI/CC cathode enables the LIBs in pouch cell to maintain the electrochemical performances under various bending states,demonstrating their potentials for flexible LIBs.

关键词： Acidic solution processing Perylene diimide Carbon clothes Organic cathodes Flexible lithium ion batteries

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Mixed D-vine copula-based conditional quantile model for stochastic monthly streamflow simulation

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Water Science and Engineering 2024年第1期17卷 13-20页

作者： Wen-zhuo Wang Zeng-chuan dong Tian-yan Zhang Li Ren Lian-qing Xue Teng wu College of Water Resources and Hydrology Hohai UniversityNanjing 210098China Yellow River Research Center Hohai UniversityNanjing 210098China

Copula functions have been widely used in stochastic simulation and prediction of ***,existing models are usually limited to single two-dimensional or three-dimensional copulas with the same bivariate block for all *** address this limitation,this study developed a mixed D-vine copula-based conditional quantile model that can capture temporal *** model can generate streamflow by selecting different historical streamflow variables as the conditions for different months and by exploiting the conditional quantile functions of streamflows in different months with mixed D-vine *** up-to-down sequential method,which couples the maximum weight approach with the Akaike information criteria and the maximum likelihood approach,was used to determine the structures of multivariate Dvine *** developed model was used in a case study to synthesize the monthly streamflow at the Tangnaihai hydrological station,the inflow control station of the Longyangxia Reservoir in the Yellow River *** results showed that the developed model outperformed the commonly used bivariate copula model in terms of the performance in simulating the seasonality and interannual variability of *** model provides useful information for water-related natural hazard risk assessment and integrated water resources management and utilization.

关键词： Stochastic monthly streamflow simulation Mixed D-vine copula Conditional quantile model Up-to-down sequential method Tangnaihai hydrological station

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Numerical Study on Local Flow and Heat Transfer Characteristics of Supercritical CO_(2) in PCHE with Sinusoidal Channels

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Journal of Thermal Science 2024年第1期33卷 41-55页

作者： WENZhexi LV Yigao LI qing wu Jinglin School of Energy Science and Engineering Central South UniversityChangsha 410083China

Local heat transfer and flow characteristics,which is crucial to the overall performance of supercritical CO_(2) recuperators,is rarely examined in details in reported *** this paper,the local heat transfer and flow characteristics of supercritical CO_(2) in sinusoidal channel printed circuit heat exchangers are numerically investigated under the working conditions of *** on the simplified physical model constituted by10 pitches,the variations of Re,heat flux,Nu,secondary flow and other relevant parameters along the flow direction are analyzed *** is further made between the high and low temperature recuperators(HTR and LTR).It's observed that the local heat transfer and flow characteristics vary greatly from the inlet to the outlet,especially in the *** of 127.5% and 61.7% can be observed on the cold side of the LTR for Re and heat transfer coefficient h, *** indicate that the temperature difference and heat transfer coefficient h should not be regarded as constant and the distribution of h should be carefully considered in the design of the *** complicated interactions among the varying thermophysical properties,buoyancy and the periodically changed centrifugal force are believed to be the key that shapes the flow ***,the changes of the wavy angle θ are found to have greater influence than the changes of mass flow rate in reshaping the flow field when θ>25°.Though gravity direction strongly affects the local heat transfer and flow characteristics,it's also found that the effects on the overall thermal-hydraulic performance are relatively *** the installation direction that yields a_y=g should better be avoided for the sinusoidal channel printed circuit heat exchanger.

关键词： printed circuit heat exchanger supercritical CO_(2) sinusoidal channel heat transfer recuperator

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State-Based Opacity Verification of Networked Discrete Event Systems Using Labeled Petri Nets

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1274-1291页

作者： Yifan dong Naiqi wu Zhiwu Li The authors are with the Institute of Systems Engineering Macao University of Science and TechnologyTaipa 999078MacaoChina

The opaque property plays an important role in the operation of a security-critical system,implying that pre-defined secret information of the system is not able to be inferred through partially observing its *** paper addresses the verification of current-state,initial-state,infinite-step,and K-step opacity of networked discrete event systems modeled by labeled Petri nets,where communication losses and delays are *** on the symbolic technique for the representation of states in Petri nets,an observer and an estimator are designed for the verification of current-state and initial-state opacity,***,we propose a structure called an I-observer that is combined with secret states to verify whether a networked discrete event system is infinite-step opaque or K-step *** to the utilization of symbolic approaches for the state-based opacity verification,the computation of the reachability graphs of labeled Petri nets is avoided,which dramatically reduces the computational overheads stemming from networked discrete event systems.

关键词： infinite system symbolic

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Enhanced hydrogen evolution reaction in FePt film with remanence due to decrease in domain walls

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Rare Metals 2024年第3期43卷 1108-1115页

作者： Hong Hong dong-Xue Liu Jun Li Jun-Ming Li Li-Qian wu Bo Yang qing-Qi Cao Dun-Hui Wang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresJiangsu Provincial Key Laboratory for NanotechnologySchool of PhysicsNanjing UniversityNanjing210093China Hangzhou Dianzi University Hangzhou310018China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang110819China

As an effective strategy to improve the properties of electrocatalysts,magnetic field-assisted electrocatalytic water splitting has attracted increasing attention ***,the corresponding enhancements mostly depend on the exertion of an external magnetic field during electrochemical reactions,which results in a high cost of industrial production,and makes the magnetic field manipulation of electrocatalysis become a challenging *** this work,instead of the external magnetic field,a bias magnetic field is self-supplied by the remanence state of a ferromagnetic electrocatalyst of *** to the assistance of this bias magnetic field,the FePt film in the remanence state shows the overpotential of 229 mV during hydrogen evolution reaction,which is much lower than that in its demagnetization state(283 mV).Our findings demonstrate that the remanence in ferromagnetic electrocatalysts can improve the catalytic performance,which is attributed to the decrease in domain walls.

关键词： Remanence Magnetic domains Electrocatalysis Hydrogen evolution reaction(HER)

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Sorafenib inhibits ossification of the posterior longitudinal ligament by blocking LOXL2-mediated vascularization

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Bone Research 2024年第2期12卷 372-389页

作者： Longqing Wang Wenhao Jiang Siyuan Zhao dong Xie qing Chen Qi Zhao Hao wu Jian Luo Lili Yang Spine Center Department of OrthopaedicsShanghai Changzheng HospitalSecond Affiliated Hospital of Naval Medical UniversityShanghai 200003PR China Yangzhi Rehabilitation Hospital(Shanghai Sunshine Rehabilitation Center) Tongji University School of MedicineShanghaiPR China Shanghai Key Laboratory of Regulatory Biology Institute of Biomedical Sciences and School of Life SciencesEast China Normal UniversityShanghaiPR China Department of Orthopaedics No.905 Hospital of PLA NavyShanghaiPR China

Ossification of the Posterior Longitudinal Ligament(OPLL)is a degenerative hyperostosis disease characterized by the transformation of the soft and elastic vertebral ligament into bone,resulting in limited spinal mobility and nerve *** both bulk and single-cell RNA sequencing,we elucidate the molecular characteristics,cellular components,and their evolution during the OPLL process at a single-cell resolution,and validate these findings in clinical *** study also uncovers the capability of ligament stem cells to exhibit endothelial cell-like phenotypes in vitro and in ***,our study identifies LOXL2 as a key regulator in this *** gain-and loss-of-function studies,we elucidate the role of LOXL2 in the endothelial-like differentiation of ligament *** acts via the HIF1A pathway,promoting the secretion of downstream VEGFA and *** function is not related to the enzymatic activity of ***,we identify sorafenib,a broad-spectrum tyrosine kinase inhibitor,as an effective suppressor of LOXL2-mediated vascular *** disrupting the coupling between vascularization and osteogenesis,sorafenib demonstrates significant inhibition of OPLL progression in both BMP-induced and enpp1 deficiency-induced animal models while having no discernible effect on normal bone *** findings underscore the potential of sorafenib as a therapeutic intervention for OPLL.

关键词： LOXL2 ligament finding

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