检索结果-南通市图书馆

Valence of elements in HgBa_2Ca_(n-1)Cu_nO_(2n+2+δ)(n=1, 2, 3, 4)

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2000年第12期11卷 1111-1112页

作者： Zhi jian WU si Yuan ZHANG Laboratory of Rare Earth Chemistry and Physics Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022

Valence of elements in HgBa_2Ca_(n-1)Cu_nO_(2n+2+δ)(n=1, 2, 3, 4) (both argon and oxygen annealed samples) were calculated. The result indicated for both argon and oxygen annealed samples, Hg had the lowest valence for the highest Tc sample. For fixed n, the valence of Cu in oxygen annealed samples was larger than that in argon annealed samples, indicating that oxygen annealed samples produce more carriers than argon annealed samples.

关键词： Valence HgBa_2Ca_(n-1)Cu_nO_(2n+2+δ)(n=1, 2, 3, 4).

Non-premixed turbulent combustion modeling based on the filtered turbulent flamelet equation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2020年第4期63卷 119-124页

作者： jian Zhang LiPo Wang YuQing guo State Key Laboratory of Nonlinear Mechanics(LNM) Chinese Academy of SciencesBeijing 100190China UM-SJTU Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China

In turbulent combustion simulations, the flow structure at the unresolved scale level needs to be reasonably modeled. Following the idea of turbulent flamelet equation for the non-premixed flame case, which was derived based on the filtered governing equations(L. Wang, Combust. Flame 175, 259(2017)), the scalar dissipation term for tabulation can be directly computed from the resolved flowing quantities, instead of solving species transport equations. Therefore, the challenging source term closure for the scalar dissipation or any assumed probability density functions can be avoided;meanwhile the chemical sources are closed by scaling relations. The general principles are discussed in the context of large eddy simulation with case validation. The new model predictions of the bluff-body flame show sufficiently improved results, compared with these from the classic progress-variable approach.

关键词： turbulent combustion modeling turbulent flamelet equation large eddy simulation non-premixed flame

EMPIRICAL VERIFICATION OF ANISOTROPIC HYDRODYNAMIC TRAFFIC MODEL IN TRAFFIC ANALYsiS AT INTERSECTIONS IN URBAN AREA

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2007年第2期19卷 230-235页

作者： WEI Yan-fang guo si-ling XUE Yu Institute of Physics Science and Engineering Guangxi University Nanning 530004 China Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China Department of Physics and Information Science Guangxi Yulin Normal University Yulin 537000 China

In this article, the traffic hydrodynamic model considering the driver＇s reaction time was applied to the traffic analysis at the intersections on real roads. In the numerical simulation with the model, the pinch effect of the right-turning vehicles flow was found, which mainly leads to traffic jamming on the straight lane. All of the results in accordance with the empirical data confirm the applicability of this model.

关键词： traffic flow hydrodynamic traffic model,intersection pinch effect

signal classification method based on data mining formulti-mode radar

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2016年第5期27卷 1010-1017页

作者： qiang guo pulong nan jian wan College of Information and Communication Engineering Harbin Engineering University Harbin 150001 China

For the multi-mode radar working in the modern electronicbattlefield, different working states of one single radar areprone to being classified as multiple emitters when adoptingtraditional classification methods to process intercepted signals,which has a negative effect on signal classification. A classificationmethod based on spatial data mining is presented to address theabove challenge. Inspired by the idea of spatial data mining, theclassification method applies nuclear field to depicting the distributioninformation of pulse samples in feature space, and digs out thehidden cluster information by analyzing distribution *** addition, a membership-degree criterion to quantify the correlationamong all classes is established, which ensures classificationaccuracy of signal samples. Numerical experiments show that thepresented method can effectively prevent different working statesof multi-mode emitter from being classified as several emitters,and achieve higher classification accuracy.

关键词： multi-mode radar signal classification data mining,nuclear field cloud model membership.

Experimental research and finite element analysis of bridge piers failed in flexure-shear modes

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2008年第4期7卷 403-414页

作者： Sun Zhiguo si Bingjun Wang Dongsheng guo Xun Institute of Road and Bridge Engineering Dalian Maritime University Dalian 116026 China School of Civil ＆ Hydraulic Engineering Dalian University of Technology Dalian 116024 China Institute of Engineering Mechanics China Earthquake Administration Harbin 150080 China

In recent earthquakes, a large number of reinforced concrete （RC） bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers. An integrated experimental and finite element （FE） analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes. In the first part, a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally. The damage states, ductility and energy dissipation parameters, stiffness degradation and shear strength of the piers are studied and compared with each other. The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure. The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking, and in some cases, rupturing of spiral bars. In the second part, modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software. A set of models with different parameters is selected and evaluated through comparison with experimental results. The influences of the shear retention coefficients between concrete cracks, the Bauschinger effect in longitudinal reinforcement, the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretic curves are discussed. Then, a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones. This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.

关键词： RC bridge piers flexure-shear failure seismic behavior finite element ANSYS software

The development,performances and applications of the monochromatic X-rays facilities in(0.218–301)keV at NIM,China

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2021年第6期32卷 108-121页

作者： si-Ming guo Jin-Jie Wu Dong-Jie Hou National Institute of Metrology BeijingChina

Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the *** worldwide have launched numerous space exploration *** calibration of the detectors on the ground is a crucial element for space science satellites to obtain observational *** the purpose of providing calibration for various satellite-borne detectors,multiple monochromatic X-rays facilities have been built at the National Institute of Metrology,***(NIM).These facilities mainly pertain to grating diffraction and Bragg diffraction,and the energy range of the produced monochromatic X-rays is 0.218–301 ke *** facilities have a high performance in terms of energy stability,monochromaticity,and flux *** monochromaticity was greater than 3.0%.The energy stability of the facility is 0.02%at 25 ke V over 8 h,and the flux stability was within 1.0%at 25 ke V over 8 *** experiments on the properties of satellite-borne detectors,such as energy linearity,energy resolution,detection efficiency,and temperature response,can be conducted at the *** far,the calibration of two satellites has been completed by the authors,and the work on three other satellites is in *** study will contribute to the advancement of X-ray astronomy the development of Chinese space science.

关键词： Monochromatic X-rays Monochromator Bragg diffraction Energy spectra Calibration

A　source　extent　analysis　of　the　Lancang　earthquake(M_s=7.6)of　1988

在线全文

学校读者我要写书评

暂无评论

Acta Seismologica sinica(English Edition) 1998年第4期11卷 393-402页

作者： si-Hua Zheng (1) jian Yang (1) 1. Center for Analysis and Prediction China Seismological Bureau 100036 Beijing China

ＡｓｏｕｒｃｅｅｘｔｅｎｔａｎａｌｙｓｉｓｏｆｔｈｅＬａｎｃａｎｇｅａｒｔｈｑｕａｋｅ（Ｍｓ＝７．６）ｏｆ１９８８ＳＩ－ＨＵＡＺＨＥＮＧ（郑斯华）ＪＩＡＮＹＡＮＧ（杨健）ＣｅｎｔｅｒｆｏｒＡｎａｌｙｓｉｓａｎｄｐｒｅ... 详细信息

ＡｓｏｕｒｃｅｅｘｔｅｎｔａｎａｌｙｓｉｓｏｆｔｈｅＬａｎｃａｎｇｅａｒｔｈｑｕａｋｅ（Ｍｓ＝７．６）ｏｆ１９８８ＳＩ－ＨＵＡＺＨＥＮＧ（郑斯华）ＪＩＡＮＹＡＮＧ（杨健）ＣｅｎｔｅｒｆｏｒＡｎａｌｙｓｉｓａｎｄｐｒｅｄｉｃｔｉｏｎ，ＣｈｉｎａＳｅｉｓ...

关键词： M_s M_s=7.6)of the earthquake extent Lancang analysis

Up-conversion of Nd^(3+)/Yb^(3+)/Tm^(3+) tri-doped CaTeO3 compound under excitation of 808 nm

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第4期40卷 1008-1013页

作者： Zhong-Qiang Ye si-guo Xiao Xiao-Liang Yang School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China

Nd^(3+)/Yb^(3+)/Tm^(3+) tri-doped CaTeO3 compounds were prepared by a solid-state reaction *** blue up-conversion(UC) luminescence at around 476 nm,which corresponds to the Tm^(3+):^(1)G_(4)→^(3)H_(6) transition,was observed under 808-nm *** Nd^(3+)→Yb^(3+)→Tm^(3+) energy transfer process was responsible for the strong blue up-conversion emission in the tri-doped *** Tm^(3+) blue up-conversion emission intensity was strongly dependent on the concentrations of Yb^(3+) and Nd^(3+).The possible up-conversion mechanisms for the Nd^(3+)/Yb^(3+)/Tm^(3+) tri-doped CaTeO_(3) phosphor are discussed,based on the Nd^(3+) and Yb^(3+) concentration-dependent UC spectra,near-infrared luminescence spectra and luminescence decay curves.

关键词： Up-conversion Tellurite 808 nm Energy transfer

Structural Manipulation of Aminal-crosslinked Polybutadiene for Recyclable and Healable Elastomers

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2021年第10期39卷 1337-1344,I0008页

作者： Zheng-Hai Tang Hui Zeng si-Qi Wei si-Wu Wu Bao-Chun guo Department of Polymer Materials and Engineering South China University of TechnologyGuangzhou 510640China

Recently,increasingly growing efforts have been devoted to incorporating dynamic covalent bonds into covalently crosslinked networks to address the persistent trade-offs between chemical crosslinking and ***,a series of dynamic aminal bond crosslinked polybutadiene rubbers(PAPB)are prepared by crosslinking aldehyde group-terminated polybutadiene rubber(APB)with *** varying the molecular weight of APB,the crosslinking density of PAPB is changed,which offers the platform to regulate the mechanical characteristics and dynamic ***,with the decrease of APB molecular weight,*** the increase of crosslinking density,the modulus of PAPB gradually increases while the elongation at break conversely decreases,and the activation energy for network rearrangement initially decreases and then *** resultant PAPB exhibit vitrimer-like behaviors that can alter the network topologies at elevated temperatures without the loss of structural integrity through dissociative aminal exchange reactions,while the protic source can accelerate aminal dissociation and result in network dissolution even at room *** to the aminal exchange,PAPB are thermally malleable and can almost restore the original mechanical characteristics after recycling;besides,they are capable of healing at a relatively low crosslinking density.

关键词： Aminal Recyclability Healing Structural manipulation Dynamic covalent network