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Oscillation properties of eigenfunctions for Sturm-Liouville problems with interface conditions via Prufer transformation

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 191-200页

作者： LI zhi-yu LI Kun CAI jin-ming QIN Jian-fang ZHENG Zhao-wen School of Mathematical Sciences Qufu Normal UniversityQufu 273165China College of Mathematics and Systems Science Guangdong Polytechnic Normal UniversityGuangzhou 510665China

A class of Sturm-Liouville problems with discontinuity is studied in this *** oscillation properties of eigenfunctions for Sturm-Liouville problems with interface conditions are *** main method used in this paper is based on Prufer transformation,which is different from the classical ***,we give two examples to verify our main results.

关键词： Sturm-Liouville problem interface condition oscillatory solution

A Second-order Fluid Queue with Subordinator Input and Markov-modulated Linear Output

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Acta Mathematicae Applicatae Sinica 2009年第2期25卷 345-352页

作者： jin-zhi Li College of Sciences Minzu University of China Beijing 100081 China

We consider an infinite capacity second-order fluid queue with subordinator input and Markovmodulated linear release rate. The fluid queue level is described by a generalized Langevin stochastic differential equation （SDE）. Applying infinitesimal generator, we obtain the stationary distribution that satisfies an integro-differential equation. We derive the solution of the SDE and study the transient level＇s convergence in distribution. When the coefficients of the SDE are constants, we deduce the system transient property.

关键词： Second-order fluid queue subordinator Markov chain linear release rate

Graphdiyne(C_(n)H_(2n-2))as an"electron transfer bridge"boosting photocatalytic hydrogen evolution over Zn_(0.5)Co_(0.5)S/MoS_(2)S-scheme heterojunction

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Rare Metals 2024年第5期43卷 1999-2014页

作者： Mei Li jing-zhi Wang zhi-Liang jin School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan 750021China School of Chemistry and Chemical Engineering Ningxia Key Laboratory of Solar Chemical Conversion TechnologyKey Laboratory for Chemical Engineering and TechnologyState Ethnic Affairs CommissionNorth Minzu UniversityYinchuan 750021China

In the process of photocatalytic water cracking,the migration rate and utilization rate of photogenerated charges determine the hydrogen evolution performance of the *** this paper,a carbon isotope superconducting material graphdiyne(GDY)is prepared by mechanical ball milling and introduced into the S-scheme heterojunction Zn_(0.5)Co_(0.5)S/MoS_(2)inorganic *** terms of hydrogen evolution kinetics,GDY acts as an electron bridge,not only accelerating the migration of photogenerated carriers but also improving the utilization of photogenerated ***,the large twodimensional layer provides more loading and anchoring points for Zn_(0.5)Co_(0.5)S/MoS_(2),which increases the number of active *** ternary composite catalyst 20%GDY/Zn_(0.5)Co_(0.5)S/MoS_(2)(20-GCSM)generates 69.94μmol of hydrogen(5 h)in triethanolamine *** is 2.97 and1.80 times higher than Zn_(0.5)Co_(0.5)S and Zn_(0.5)Co_(0.5)S/MoS_(2),*** the cyclic experiment,it still has stable hydrogen evolution performance after standing for24 h(under dark conditions).In addition,the potential mechanism of photocatalytic hydrogen evolution is demonstrated through in-situ X-ray photoelectron *** work provides a reference for further research in the field of introducing carbon materials into photocatalytic systems and improving the utilization of photogenerated charges.

关键词： Graphdiyne S-scheme heterojunction Electron transfer bridge Hydrogen production

NUMERICAL STUDY OF NON-AQUEOUS PHASE LIQUID TRANSPORT IN A SINGLE FILLED FRACTURE BY LATTICE BOLTZMANN METHOD

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Journal of Hydrodynamics 2012年第1期24卷 130-137页

作者： DOU zhi ZHOU zhi-fang HUANG Yong WU Wei School of Earth Science and Engineering Hohai UniversityNanjing 210098China School of Materials Science and Engineering Southeast UniversityNanjing 211189China

In this article,the Non-Aqueous Phase Liquid（NAPL）transport in the single filled fracture was studied with the Shan-Chen multi-component multiphase Lattice Boltzmann Method（LBM）with special consideration of wettability *** the help of the model,the contact angle of the non-wetting phase and wetting phase interface at a solid wall could be *** considering a set of appropriate boundary conditions,the fractured conductivity was investigated in condition that the NAPL blocks the channels in the single filled *** order to study the wettability effects on the NAPL transport,a constant driving force was introduced in the Shan-Chen multi-component multiphase *** regimes with different wettabilities were *** results show that the LBM is a very instrumental method for simulating and studying the immiscible multiphase flow problems in single filled fracture.

关键词： single filled fracture Lattice Boltzmann Method(LBM) Non-Aqueous Phase Liquid(NAPL)transport wettability contact angle immiscible two-phase flow

A study of variable stars in the open cluster NGC 1582 and its surrounding field

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Research in Astronomy and Astrophysics 2016年第10期16卷 35-44页

作者： fang-fang Song Ali Esamdin Lu Ma jin-Zhong Liu Yu Zhang Hu-Biao Niu Tao-zhi Yang Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China

This paper presents Charge-Coupled Device time-series photometric observations of the open cluster NGC 1582 and its surrounding field with Johnson B, V and R filters by using the Nanshan 1 m telescope administered by Xinjiang Astronomical Observatory. 19 variable stars and three variable candi- dates were detected in a 45＇ - 48.75＇ field around the cluster. 12 of the variable stars are newly-discovered variable objects. The physical properties, classifications and memberships of these 22 objects are studied through their light curves, their positions on the color-magnitude diagram and with archival data from the Naval Observatory Merged Astrometric Dataset. Among these objects, five are eclipsing binary systems, six are pulsating variable stars including one known 6 Scuti star and one newly-discovered RR Lyrae star. The distance to the RR Lyrae star is estimated to be 7.9 - 0.3 kpc, indicating that the star is located far behind the cluster. Four variable stars are probable members of the cluster, and 13 of the 22 objects are confirmed to be field stars.

关键词： NGC 1582 -- open cluster -- variable stars -- multi-color observation -- magnitude

Experimental study on shear behavior of prestressed reactive powder concrete I-girders

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 618-627页

作者： Hui ZHENG zhi fang Bin CHEN College of Civil Engineering Hunan University of TechnologyZhuzhou 412007China College of Civil Engineering Hunan UniversityChangsha 410082China

As a new generation of concrete,RPC(Reactive Powder Concrete)has attracted great research attention for its ultra-high strength and high *** the present paper,experimental results from tests on eight prestressed RPC I-section girders failing in shear are reported *** beams with RPC of 120 MPa in compression were designed to assess the ability to carry shear stress in thin webbed prestressed beams with *** test variables were the level of prestressing,shear span-depth ratio(a/d)and stirrup *** deformation,shear capacity and crack pattern were experimentally investigated in *** regard to the shear resistance of the test beams,the predictions from three standards(AFGC,JSCE and SIA)on the design of UHPC structures were compared with the experimental result suggesting that the experimental strength is almost always higher than ***,as a new concrete,was different from normal concrete and fiber reinforced *** study should be needed to develop an analytical method and computation model for shear strength of RPC beams.

关键词： prestressed concrete RPC(Reactive Powder Concrete) concrete beams shear strength experimental study

Theoretical Study on the Catalytic Activity and Sulfur Resistibility of Amorphous Alloy Ni-B-P

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Chinese Journal of Structural Chemistry 2007年第3期26卷 273-280页

作者： fang zhi-Gang GUO jing-Xue School of Chemical Engineering University of Science and Technology Liaoning Anshan 114051 China

In the present paper, one hundred cluster models NinBP （n = 1-6） have been designed and studied by density functional theory （DFT） to get an insight into the local structure, catalytic properties and sulfur resistibility of amorphous alloy Ni-B-P. The configurations in triplet state are found more stable than those in the singlet state. It is found： that as the content of Ni in the clusters increases, the value of Fermi level in clusters fluctuated, which shows that the content of Ni can influence the Fermi level to a certain extent. Based on the Fermi level and DOS, we consider the activity of catalyst in hydrogenation reaction is the best in cluster Ni3BP. On the basis of the charge of clusters NinBP （n = 1 -6）, we conclude the amorphous alloy Ni-B-P with high Ni content has better sulfur resistibility and the best hydrogenation activity, strong sulfur resistibility appears in clusters Ni3BP, and the amorphous alloy Ni60B20P20 with similar proportion is expected to prepare in the future.

关键词： amorphous alloy Ni-B-P DFT catalytic activity sulfur resistibility

Gas compression and likely triggered star formation in the infrared bubble N107

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Research in Astronomy and Astrophysics 2018年第10期18卷 49-64页

作者： Hao Li jin-Zeng Li jing-Hua Yuan Ya-fang Huang zhi-Yuan Ren National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Science University of Chinese Academy of Sciences

The expansion of HII regions can regulate the evolution of their natal clouds and the star for-mation therein. Infrared dust bubbles, which are frequently associated with HII regions, are ideal labora-tories to test whether impulse（s） driven by the expanding bubbles enhances or suppresses star-formation. In this work, we present a comprehensive study of a 20-pc scale infrared bubble N107 to reveal the com- pression of the neutral gas and associated star-forming activities. We obtain column density （NH2） and dust temperature （Tdust） maps via fitting modified blackbodies to multi-band far-infrared Herschel data. The shell structure can be recognized on the column density map. The molecular gas along the rim of N107 fragments into 94 dense clumps at an angular resolution of 18＂. Besides, based on the GLIMPSE point source catalog, we have identified 228 young stellar objects （YSOs） which are categorized into 55 Class I objects, 127 Class II objects and 46 transition disks （TDs）. The 94 clumps and 55 Class I type YSOs are mainly distributed along the shell, which may suggest triggered star formation exists in N107. In addition, analysis of NH2 probability density functions （PDFs） helps us reveal the condition of natal clouds. The two lognormal profiles of PDFs suggest that the surrounding molecular gas has been compressed due to expansion of the bubble. This compression may trigger the star formation process. Moreover, we find the shape of the PDFs changed after removing the background. Taken together, this big bubble seems to compress the surrounding gas and strongly regulate star formation therein.

关键词： ISM HII regions - ISM clouds - stars formation - ISM structure - methods observational

NUMERICAL INVESTIGATION OF CAVITATION PERFORMANCE OF SHIP PROPELLERS

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Journal of Hydrodynamics 2012年第3期24卷 347-353页

作者： ZHU zhi-feng fang Shi-liang Key Laboratory of Underwater Acoustic Signal Processing Ministry of Education Southeast University Nanjing 210096 China School of Electrical Engineering and Information Anhui University of Technology Maanshan 243002 China Key Laboratory of Underwater Acoustic Signal Processing Ministry of Education Southeast University Nanjing 210096 China

The cavitation performance of propellers is studied based on viscous multiphase flow theories. With a hybrid grid based on Navier-Stokes （N-S） and bubble dynamics equations, some recent validation results are presented in this paper in the predictions of the thrust, the torque and the vapor volume fraction on the back side of propeller blade for a uniform inflow. The numerical predictions of the hydrodynamic performance and the sheet cavitation under several operating conditions for two propellers agree with the corresponding measured data in general. The thrust and the torque are plotted with respect to the advance rate and the cavitation number. The cavitation performance breakdown is closely related to the strong sheet cavitation around propellers. The models with parameters modified are shown to predict the propeller cavitation well.

关键词： cavitation Reynolds-Averaged Navier-Stokes (RANS) propeller sliding mesh multiphase flow