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Clustering Property of Wolf-Rayet Galaxies in the SDSS

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Chinese Journal of Astronomy and Astrophysics 2008年第2期8卷 211-218页

作者： Wei zhang xu Kong Fu-Zhen Cheng Center for Astrophysics University of Science and Technology of China Hefei 230026

We have analysed, for the first time, the clustering properties of Wolf-Rayet （W-R） galaxies, using a large sample of 846 W-R galaxies selected from the Data Release 4 （DR4） of the Sloan Digital Sky Survey （SDSS）. We compute the cross-correlation function between W- R galaxies and a reference sample of galaxies drawn from the DR4. We compare the function to the results for control samples of non-W-R star-forming galaxies that are matched closely in redshift, luminosity, concentration, 4000-A break strength and specific star formation rate （SSFR）. On scales larger than a few Mpc, W-R galaxies have almost the same clustering amplitude as the control samples, indicating that W-R galaxies and non-W-R control galaxies populate dark matter haloes of similar masses. On scales between 0.1-1 h^-1 Mpc, W-R galaxies are less clustered than the control samples, and the size of the difference depends on the SSFR. Based on both observational and theoretical considerations, we speculate that this negative bias can be interpreted by W-R galaxies residing preferentially at the centers of their dark matter haloes. We examine the distribution of W-R galaxies more closely using the SDSS galaxy group catalogue of Yang et al., and find that -82% of our W-R galaxies are the central galaxies of groups, compared to -74% for the corresponding control galaxies. We find that W-R galaxies are hosted, on average, by dark matter haloes of masses of 10^12.3M⊙, compared to 10^12.1M⊙ for centrally-located W-R galaxies and 10^12.7M⊙ for satellite ones. We would like to point out that this finding, which provides a direct observational support to our conjecture, is really very crude due to the small number of W-R galaxies and the incompleteness of the group catalogue, and needs more work in future with larger samples.

关键词： galaxies: distances and redshifts -- galaxies: starburst -- stars: Wolf-Rayet

Localization and characterization of intermittent pollutant source in buildings with ventilation systems:Development and validation of an inverse model

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Building Simulation 2021年第3期14卷 841-855页

作者： Lingjie Zeng Jun Gao Lipeng Lv Bowen Du Yalei zhang Ruiyan zhang Wei Ye xu zhang College of Environmental Science and Engineering Tongji UniversityShanghai200092China School of Mechanical Engineering Tongji UniversityShanghai 200092China Department of Civil and Mineral Engineering University of TorontoTorontoCanada

Terrorist attacks through building ventilation systems are becoming an increasing *** case pollutants are intentionally released in a building with mechanical ventilation systems,it is critical to localize the source and characterize its releasing *** inverse modeling studies have adopted the adjoint probability method to identify the source location and used the Tikhonov regularization method to determine the source releasing profile,but the selection of the prediction model and determination of the regularization parameter remain *** limitations can affect the identification accuracy and prolong the computational time *** address the difficulties in solving the inverse problems,this work proposed a Markov-chain-oriented inverse approach to identify the temporal release rate and location of a pollutant source in buildings with ventilation systems and validated it in an experimental *** the modified Markov chain,the source term was discrete by each time step,and the pollutant distribution was directly calculated with no *** forward Markov chain was reversed to characterize the intermittently releasing profile by introducing the Tikhonov regularization method,while the regularized parameter was determined by an automatic iterative discrepancy *** source location was further estimated by adopting the Bayes *** chamber experiments,the effectiveness of the proposed inverse model was validated,and the impact of the sensor performance,quantity and placement,as well as pollutant releasing curves on the identification accuracy of the source intensity was explicitly *** showed that the inverse model can identify the intermittent releasing rate efficiently and promptly,and the identification error for pollutant releasing curves with complex waveforms is about 20%.

关键词： intermittent source inverse identification Markov chain regularization parameter ventilation system

Localization of normalized solutions for saturable nonlinear Schr?dinger equations

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Science China Mathematics 2023年第11期66卷 2495-2522页

作者： Xiaoming Wang Zhi-Qiang Wang xu zhang School of Mathematics&Computer Science Shangrao Normal UniversityShangrao 334001China College of Mathematics and Statistics Fujian Normal UniversityFuzhou 350117China Department of Mathematics and Statistics Utah State UniversityLoganUT 84322USA School of Mathematics and Statistics Central South UniversityChangsha 410083China

In this paper,we study the existence and concentration behavior of the semiclassical states with L2-constraints for the following saturable nonlinear Schr?dinger equation:-ε2Δv+Γ(I(x)+v^(2))/(1+I(x)+v^(2))v=λv for x∈*** a negatively large coupling constantΓ,we show that there exists a family of normalized positive solutions(i.e.,with the L2-constraint)whenεis small,which concentrate around local maxima of the intensity function I(x)asε→*** also consider the case where I(x)may tend to-1 at infinity and the existence of multiple *** proof of our results is variational and the novelty of the work lies in the development of a new truncation-type method for the construction of the desired solutions.

关键词： saturable nonlinear Schrodinger equation normalized solutions semiclassical states local maximum potential

Sn_(4)P_(3)-induced crystalline/amorphous composite structures for enhanced sodium-ion battery anodes

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Journal of Materials Science & Technology 2020年第20期52卷 73-80页

作者： Jaffer Saddique xu zhang Tianhao Wu Heng Su Shiqi Liu Dian zhang Yuefei zhang Haijun Yu College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials of Education Ministry of ChinaBeijing University of TechnologyBeijing 100124China Institute of Microstructure and Property of Advanced Materials Beijing University of TechnologyBeijing 100124China

The optimization of anode materials such as Sn,P and Sn4P3 in terms of capacity and cyclability is crucial to improve the overall performance of sodium-ion ***,the delicate fabrication of these materials,including the balanced crystalline/amorphous domains,reasonable particle size and distribution,complementary components exhibiting synergetic reactions,among others,still greatly retards the realization of maximum ***,a series of Sn/P-based composite materials with a plum pudding configuration were fabricated to achieve controlled crystalline/amorphous structures as well as optimized size and distribution in a carbon *** using a facile and low-cost ball milling method,the structural transformation of Sn4P3 into phase-separated crystalline Sn and amorphous P in a carbonaceous framework can be finely controlled,producing a series of binary(Sn4 P3/C),quaternary(Sn4P3/Sn/P/C) and ternary(Sn/P/C) *** to the complementary components,crystalline/amorphous adjustment,crystallite sizes and well-integrated interfaces,the quaternary Sn4P3/Sn/P/C composite showed the best electrochemical performance,with a noticeable long-cycle performance of 382 mA hg-1 and 86% capacity retention for nearly 300 *** from binary and ternary composites,the discharge of quaternary composite generates no noticeable signals of Na15Sn4 and Na3 P in the ex-situ X-ray diffraction patterns,suggesting the crystallite growth of sodiation products can be ***,Sn4 P3 in the quaternary composite can be partially regenerated in the desodiation reaction,implying the significant short-range interaction and thus better synergetic reactions between Sn and P *** results demonstrate that the design and organization of crystalline/amorphous structures can serve as an efficient strategy to develop novel electrode materials for sodium ion batteries.

关键词： Sodium ion battery Tin phosphides Anode materials Composite structure Reaction mechanism

Silver Nano Islands Enhanced Raman Scattering on Large Area Grating Substrates Fabricated by Two Beam Laser Interference

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Chemical Research in Chinese Universities 2013年第5期29卷 1006-1010页

作者： ABID Muhammad Irfan WANG Lei zhang xu-lin xu Ying State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering Jilin University Changchun 130012 P. R. China

The authors prepared large area surface-enhanced Raman scattering（SERS） active substrates with tunable enhancement. First the large area gratings were fabricated by scanning a photoresist with two-beam laser interference and subsequently they were coated with silver nano islands via vacuum evaporation. SERS active metal island grating substrates with four different periods（300, 400, 515 and 600 nm） and Ag nano islands uniformly coated on an area of 2.5 cm×0.5 cm were obtained. The measured SERS spectra reveal the tuning effect of the period on the Raman sig- nals period. The highest enhancement（ca. 105） for Rhodamine 6G（R6G） as probing molecule is associated with a pe- riod of 515 nm due to the perfect matching of surface plasmons and Raman excitation line. A good reproducibility of SERS signals with almost the same SERS intensity at different spots was observed on all the larger area Ag island grating substrates.

关键词： Ag nano island Surface-enhanced Raman scattering Large area grating Laser interference

Experimental research on charging characteristics of a solar photovoltaic system by the pressure-control method

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 470-474页

作者： Hua ZHU zhang-lu xu Zi-juan CAO Institute of Thermal Science and Power Systems Zhejiang University Hangzhou 310027 China

The charging characteristics of the valve-regulated lead acid(VRLA) battery driven by solar energy were experimentally studied through the pressure-control method in this *** aims of the research were to increase charging efficiency to make the most of solar energy and to improve charging quality to prolong life of *** charging process of a 12 V 12 A·h VRLA battery has been tested under the mode of a stand-alone photovoltaic(PV) *** show that the pressure-control method can effectively control PV charging of the VRLA battery and make the best of PV cells through the maximum power point tracking(MPPT).The damage of VRLA battery by excess oxygen accumulation can be avoided through the inner pressure control of VRLA *** such as solar radiation intensity,charging power,inner pressure of the battery,and charging current and voltage during the charging process were measured and analyzed.

关键词： Solar photovoltaic(PV) system Charging characteristics Pressure-control method

ENTERPRISE INTEGRATION PLATFORM BASED ON SERVICEORIENTED ARCHITECTURE

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Chinese Journal of Mechanical Engineering 2008年第3期21卷 36-40页

作者： MENG Xiaojun zhang xu NING Ruxin SONG Yu School of Mechanical and Vehicle Engineering Beijing Institute of Technology Beijing 100081 China Department of Scientific Research Taishan University Taian 271021 China School of Mechanical and Vehicle Engineenng Beijing Institute of Technology Beijing 100081 China

To achieve information integration, process integration and application integration of enterprise, an enterprise integration platform （EIP） based on service-oriented architecture （SOA） is built. The enterprise integration model depending on encapsulating the business processes as well as the enterprise applications by the neutral and standard web services is presented. The problem how to discover the existed enterprise resources and share them was resolved depending on the mechanism of publishing and discovering the services. The EIP is integrated closely with product lifecycle management （PLM） system so that the process integration as well as orchestration of the business process services is implemented by encapsulating the workflow engine of PLM system. Not only process integration and application integration, but also information integration based on the bill of material （BOM） conversion driven by process are achieved. Finally, an interpretive, qualitative case study on EIP is conducted for this research.

关键词： Enterprise integration platform (EIP) Service-oriented architecture (SOA) Information integration Process integration Application integration

Mass Spectral Fragmentation of (S,S)-N,N′-Bis [1-(hydroxymethyl)alkyl]anthracene/Naphthalene-1,8-dicarboxamides under Electron Impact Ionization Conditions

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Chemical Research in Chinese Universities 2006年第6期22卷 756-759页

作者： JIAO Peng zhang Qi-han xu Jia-xi Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The mass spectrometric fragmentation of （ S, S） -N, N＇-bis [ 1- （hydroxymethyl） alkyl] anthracene/naphthalene-1, 8-dicarboxamides was investigated with the aid of mass-analyzed ion kinetic energy spectrometry and the elemental compositions of important fragment ions were determined by accurate mass measurement under electron impact ionization conditions. All the compounds could eliminate formaldehyde. The [ M-CH2O] ions could also eliminate imine, aziridine, aziridinone, 2-amonoalkan-1-ol, water, and other fragments. Several cyclizations were observed under electron impact ionization.

关键词： Biscarboxamide EI-MS Fragmentation Cyclization

Changes of marine productivity and sedimentary environment recorded by biogenic components in the Antarctica Ross Sea since the last deglaciation

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Journal of Oceanology and Limnology 2020年第6期38卷 1746-1754页

作者： XIU Chun DU Ming zhang xu HUO Suxia North China Sea Environmental Monitoring Center of Ministry of Natural Resources Qingdao 266033China East Sea Marine Environmental Investigating and Surveying Center of Ministry of Natural Resources Shanghai 200137China

Changes in the marine productivity and sedimentary environment since the last deglaciation in the Ross Sea are presented in this *** has replaced calcium carbonate as the major biogenic component and has a significantly positive correlation with total organic carbon(TOC),which indicates that siliceous phytoplankton controlled the absorption and release of carbon by the biological pump and was the main producer of marine organic *** the AMS 14C age framework,foraminiferal fossils and redox sensitive elements(RSEs),we found that both the sedimentary environment and marine productivity changed clearly in^11 cal ka BP,which is more likely related with the melting and retreat of the Ross Ice *** addition,the increase of marine productivity promoted the sinking of more organic-matter to the seabed.A large proportion of oxygen in the bottom water body was consumed and more carbon dioxide was produced during the decomposition of organic matter,making the bottom water body more soluble to calcium carbonate.

关键词： biogenic components marine productivity redox environment ice shelf retreat the Ross Sea