检索结果-南通市图书馆

Influence of seismicity parameter uncertainty on seismic hazard estimation of cities and towns

在线全文

学校读者我要写书评

暂无评论

Acta Seismologica Sinica(English Edition) 2003年第6期16卷 632-638页

作者： HUANG Wei-qiong(黄玮琼) WU Xuan(吴宣) Institute of Geophysics China Seismological Bureau Beijing 100081 China 　

The influence on seismic hazard estimation for 310 cities and towns in the whole nation are studied in particular,owing to uncertainty of seismicity parameters caused by non-uniqueness in selecting statistical time ranges. Andthe regional sketch maps of the average varying values of intensity and the average relative varying values of peakacceleration with different probability of exceedance in 50 years are drawn in the Chinese mainland.

关键词： statistical time range uncertainty of parameters hazard estimation of cities and towns averagevarying value

Effects of Inhibitory Signal on Criticality in Excitatory-Inhibitory Networks

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2019年第6期71卷 746-752页

作者：王帆王圣军 Physics and Information Technology Shaanxi Normal University

We study the criticality in excitatory-inhibitory networks consisting of excitable elements. We investigate the effects of the inhibitory strength using both numerical simulations and theoretical analysis. We show that the inhibitory strength cannot affect the critical point. The dynamic range is decreased as the inhibitory strength increases.To simulate of decreasing the efficacy of excitation and inhibition which was studied in experiments, we remove excitatory or inhibitory nodes, delete excitatory or inhibitory links, and weaken excitatory or inhibitory coupling strength in critical excitatory-inhibitory network. Decreasing the excitation, the change of the dynamic range is most dramatic as the same as previous experimental results. However, decreasing inhibition has no effect on the criticality in excitatory-inhibitory network.

关键词： criticality excitable network dynamic range

Ensemble prediction experiments using conditional nonlinear optimal perturbation

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2009年第4期52卷 511-518页

作者： JIANG ZhiNa MU Mu WANG DongHai State Key Laboratory of Severe Weather(LaSW) Chinese Academy of Meteorological SciencesBeijing 100081China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of At-mospheric PhysicsChinese Academy of SciencesBeijing 100029China

Two methods for initialization of ensemble forecasts are compared, namely, singular vector (SV) and conditional nonlinear optimal perturbation (CNOP). The comparison is done for forecast lengths of up to 10 days with a three-level quasi-geostrophic (QG) atmospheric model in a perfect model scenario. Ten cases are randomly selected from 1982/1983 winter to 1993/1994 winter (from December to the following February). Anomaly correlation coefficient (ACC) is adopted as a tool to measure the quality of the predicted ensembles on the Northern Hemisphere 500 hPa geopotential height. The results show that the forecast quality of ensemble samples in which the first SV is replaced by CNOP is higher than that of samples composed of only SVs in the medium range, based on the occurrence of weather re-gime transitions in Northern Hemisphere after about four days. Besides, the reliability of ensemble forecasts is evaluated by the Rank Histograms. The above conclusions confirm and extend those reached earlier by the authors, which stated that the introduction of CNOP improves the forecast skill under the condition that the analysis error belongs to a kind of fast-growing error by using a barotropic QG model.

关键词： ensemble prediction medium range singular vector conditional nonlinear optimal perturbation

Packing Dimension of Space-time Anisotropic Gaussian Random Fields

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2021年第12期37卷 1826-1840页

作者： hen Long CHEN Jun WANG Dong Sheng WU School of Statistics and Mathematics Zhejiang Gongshang UniversityHangzhou 310018P.R.China School of Mathematics and Finance Chuzhou UniversityChuzhou 239000P.R.China Department of Mathematical Sciences University of Alabama in HuntsvilleHuntsvilleAlabama 35899USA

Let X={X(t)∈R^(d),t∈R^(N)}be a centered space-time anisotropic Gaussian random field whose components are independent and satisfy some mild conditions.We study the packing dimension of range X(E)under the anisotropic(time variable)metric space(R^(N),ρ)and(space variable)metric space(R^(d),τ),where E⊂R^(N) is a Borel set.Our results generalize the corresponding results of Estrade,Wu and Xiao(Commun.Stoch.Anal.,5,41-64(2011))for time-anisotropic Gaussian random fields to space-time anisotropic Gaussian fields.

关键词： Gaussian random fields anisotropic packing dimension packing dimension profile range

A new method of estimating the equivalent elastic modulus of RCCD

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2007年第Z1期50卷 136-143页

作者： GU ChongShi1,2?, WU Yuan1, SU HuaiZhi1,2 & TANG LiHui1 1 College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China 2 National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Nanjing 210098, China College of Water Conservancy and Hydropower Engineering Hohai University Nanjing China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Nanjing China

Based on the composite material mechanic theory, the analysis method for the equivalent elastic moduli which are parallel and vertical to the construction interface of RCCD is studied in this paper. The differences between the equivalent elastic moduli which are vertical to the construction interface of RCCD gotten from different methods are discussed in detail. The variation range of the equivalent elastic modulus which is vertical to the construction interface of RCCD is studied based on the principle of minimum complementary energy and the principle of minimum potential energy. The effect of the related influential factors on the equivalent elastic modulus is analyzed. The estimation formula of the equivalent modulus which is vertical to the construction interface of RCCD is proposed. The feasibility of the approach proposed in this paper is analyzed through an example.

关键词： RCCD equivalent elastic modulus variation range estimation method

SOME CHARACTERS OF A CLASS OF ORNSTEIN-UHLENBECK TYPE MARKOV PROCESSES WITH STABLE PROCESSES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 1997年第2期17卷 121-128页

作者：王永进 Department of Mathematics Nankai University Tianjin 300071 China

This article concerns a class of Ornstein-Uhlenbeck type Markov processes and for which the level sets will be approached. By constructing a new class f processes, we shall obtain an inequality on the Hausdorff dimensions of the level sets for the Ornstein-Uhlenbeck type Markov processes. Based on this result, we finally verify that any two independent O-U.M.P with alpha-stable processes could collide with probability one.

关键词： alpha-stable process Ornstein-Uhlenbeck type Markov process range Hausdorff dimension collision

An improved protein expression system for T3SS genes regulation analysis in Xanthomonas oryzae pv. oryzae

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2019年第6期18卷 1189-1198页

作者： XU Jin-bo ZHANG Cui-ping WUNIERBIEKE Mei-li YANG Xiao-fei LI Yi-lang CHEN Xiao-bin CHEN Gong-you ZOU Li-fang Department of Environment and Resource School of Agriculture and BiologyShanghai Jiao Tong University

Xanthomonas oryzea pv.oryzae(Xoo)is the causal agent of bacterial blight of rice,which is a significant threat to many of rice-growing regions.The type Ⅲ secretion system(T3SS)is an essential virulence factor in Xoo.Expression of the T3SS is often induced in the host environment or in hrp-inducing medium but is repressed in nutrient-rich medium.The elucidation of molecular mechanism underlying induction of T3SS genes expression is a very important step to lift the veil on global virulence regulation network in Xoo.Thus,an efficient and reliable genetic tool system is required for detection of the T3SS proteins.In this study,we constructed a protein expression vector pH3-flag based on the backbone of pHM1,a most widely used vector in Xoo strains,especially a model strain PXO99A.This vector contains a synthesized MCS-FLAG cassette that consists of a multiple cloning site(MCS),containing a modified pUC18 polylinker,and Flag as a C-terminal tag.The cassette is flanked by transcriptional terminators to eliminate interference of external transcription enabling detection of accurate protein expression.We evaluated the potential of this expression vector as T3SS proteins detection system and demonstrated it is applicable in the study of T3SS genes expression regulation in Xoo.This improved expression system could be very effectively used as a molecular tool in understanding some virulence genes expression and regulation in Xoo and other Xanthomonas spp.

关键词： Xanthomonas oryzae pv.oryzae broad-host range vector expression vector T3SS genes

Asymptotic entropy of the ranges of random walks on discrete groups

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2020年第6期63卷 1153-1168页

作者： Xinxing Chen Jiansheng Xie Minzhi Zhao School of Mathematical Sciences Shanghai Jiaotong UniversityShanghai 200240China Shanghai Center of Mathematics Fudan UniversityShanghai 200433China School of Mathematical Sciences Fudan UniversityShanghai 200433China School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China

Inspired by Benjamini et al.(2010) and Windisch(2010),we consider the entropy of the random walk ranges Rn formed by the first n steps of a random walk S on a discrete group.In this setting,we show the existence of hR:=limn→∞H(Rn)/n called the asymptotic entropy of the ranges.A sample version of the above statement in the sense of Shannon(1948) is also proved.This answers a question raised by Windisch(2010).We also present a systematic characterization of the vanishing asymptotic entropy of the ranges.Particularly,we show that hR=0 if and only if the random walk either is recurrent or escapes to negative infinity without left jump.By introducing the weighted digraphs Γn formed by the underlying random walk,we can characterize the recurrence property of S as the vanishing property of the quantity limn→∞H(Γn)/n,which is an analogue of hR.

关键词： random walk entropy range recurrent

Genesis of the Bianjiadayuan Pb-Zn polymetallic deposit, Inner Mongolia, China:Constraints from in-situ sulfur isotope and trace element geochemistry of pyrite

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第5期10卷 1863-1877页

作者： Kai-Rui Song Li Tang Shou-Ting Zhang M. Santosh Christopher J. Spencer Yu Zhao Hao-Xing Li Liang Wang An-Li Zhang Yin-Qiang Sun School of the Earth Sciences and Resources China University of Geosciences (Beijing)Beijing 100083China Centre for Tectonics Exploration and ResearchUniversity of AdelaideAdelaideSA5005Australia School of Earth and Planetary Sciences The Institute of Geoscience ResearchCurtin UniversityPerthWA6845Australia Lituo Mining Company Chifeng 024000China 243 Team China Nuclear GeologyChifeng 024000China

The Southern Great Xing’an range (SGXR) which forms part of the eastern segment of the Central Asian Orogenic Belt (CAOB) is known as one of the most important Cu-Mo-Pb-Zn-Ag-Au metallogenic belts in China,hosting a number of porphyry Mo (Cu),skarn Fe (Sn),epithermal Au-Ag,and hydrothermal veintype Ag-Pb-Zn ore deposits.Here we investigate the Bianjiadayuan hydrothermal vein-type Ag-Pb-Zn ore deposit in the southern part of the SGXR.Porphyry Sn ±Cu ± Mo mineralization is also developed to the west of the Ag-Pb-Zn veins in the ore field.We identify a five-stage mineralization process based on field and petrologic studies including (i) the early porphyry mineralization stage,(ii) main porphyry mineralization stage,(iii) transition mineralization stage,(iv) vein-type mineralization stage and (v) late mineralization stage.Pyrite is the predominant sulfide mineral in all stages except in the late mineralization stage,and we identify corresponding four types of pyrites: Py1 is medium-grained subhedral to euhedral occurring in the early barren quartz vein;Py2 is medium- to fine-grained euhedral pyrite mainly coexisting with molybdenite,chalcopyrite,minor sphalerite and galena;Py3 is fine-grained,subhedral to irregular pyrite and displays cataclastic textures with micro-fractures;Py4 occurs as euhedral microcrystals and forms irregularly shaped aggregate with sphalerite and galena.LA-ICP-MS trace element analyses of pyrite show that Cu,Pb,Zn,Ag,Sn,Cd and Sb are partitioned into pyrite as structurally bound metals or mineral micro/nano-inclusions,whereas Co,Ni,As and Se enter the lattice via isomorphism in all types of pyrite.The Cu,Zn,Ag,Cd concentrations gradually increase from Py1 to Py4,which we correlate with cooling and mixing of ore-forming fluid with meteoric water.Py2 contains the highest contents of Co,Ni,Se,Te and Bi,suggesting high temperature conditions for the porphyry mineralization stage.Ratios of Co/Ni (0.03-10.79,average 2.13) and sulphur isotope composition of sulfide indicate typical hydrothermal origi

关键词： Trace elements In-situ sulfur isotope Pyrite Bianjiadayuan deposit Southern Great Xing'an range