RXTE /ASM and Swift /BAT observations of spectral transitions in bright X-ray binaries in 2005-2010     

Jing Tang  Wen-Fei Yu  Zhen Yan Key Laboratory for Research in Galaxies  Cosmology  Shanghai Astronomical Observatory  Shanghai  China 《中国天文和天体物理学报》2011,(4)

We have studied X-ray spectral state transitions that can be seen in the longterm monitoring light curves of bright X-ray binaries from the All-Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE) and the Burst Alert Telescope (BAT) onboard Swift during a period of five years from 2005 to 2010.We have applied a program to automatically identify the hard-to-soft (H-S) spectral state transitions in the bright X-ray binaries monitored by the ASM and the BAT.In total,we identified 128 hard-to-soft t...  相似文献   

BL Lacertae objects and the extragalactic γ-ray background     

Fan Li  Xin-Wu Cao Key Laboratory for Research in Galaxies  Cosmology  Shanghai Astronomical Observatory  Chinese Academy of Sciences  Shanghai  China Graduate University of Chinese Academy of Sciences  Beijing  China 《中国天文和天体物理学报》2011,(8)

A tight correlation between γ-ray and radio emission is found for a sample of BL Lacertae(BL Lac) objects detected by the Fermi Gamma-ray Space Telescope(Fermi) and the Energetic Gamma-Ray Experiment Telescope(EGRET) . The γ-ray emission of BL Lac objects exhibits strong variability,and the detection rate of γ-ray BL Lac objects is low,which may be related to the γ-ray duty cycle of BL Lac objects. We estimate the γ-ray duty cycle,δγ 0.11,for BL Lac objects detected by EGRET and Fermi. Using the empirical r...  相似文献   

SEDIMENT LOAD AND ITS INFLUENCE ON CHANNEL PROCESSES OF SOME LARGE RIVERS IN RUSSIA AND CHINA~1     

LIU Shuguang  CHALOV R.S  WU Dandan  LI Congxian Postdoctor  Research Fellow  Key Laboratory of Marine Geology  Tongji University  Shanghai  China & Researcher  State Key Laboratory of Estuarine  Coastal Research  Shanghai  China Professo 《国际泥沙研究》2000,(3)

I INTRODUCTIONThe volume and regime of sediment load are the most important factors, which are responsible for theformation, direction and deformation rate of the river channels. Despite the long history of study anddevelopment of sediment load calculation methodology, there are still numerous problems that remain tobe solved such as river pattern and sediment movement and so on (Wang et al, 1997).In this respect, the comparative analysis of sediment load and river channel processes of la…  相似文献   

The Behaviour of LNG Carrier Moored to a Jetty Exposed to Waves,Swell,Unsteady Wind and Current     

J. E. W. WICHERS 《中国海洋工程》1999,(1)

—Most terminals for tankers are piers and sea islands,while other types include single pointmoorings and multiple-buoy moorings.The LNG and LPG carrier moored to the jetty is a very commonterminal for transfer of gas in open seas.It is important to estimate the motions and line tensions of theLNG carrier when it moors to a jetty in metocean environment.Normally,the motions of the LNG carrierwould be restricted by the loading arm,which is connected to LNG carrier＇s manifold.An example of125,000m~3 LNG carrier moored to a jetty exposed to a set of environment conditions is given.Amathematical model which is based on the equations of motion in the time domain is used to the analysisof LNG moored to an offshore jetty exposed to waves,swell,wind and current.By means of a time do-main computer program TERMSIM computations are carried out to determine and optimize the lay-outand/or orientation of the jetty and mooring gear in terms of forces in mooring lines and fenders and theenvelope of motions of the loadi  相似文献   

Ultimate Compressive Strength Prediction for Stiffened Panels by Counterpropagation Neural Networks (CPN)     

WEI Dong  ZHANG Shengkun Ph.D. Candidate  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai  P. R. China Professor  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai  P. R. China 《中国海洋工程》1999,(3)

Stiffened Panels are important strength members in ship and offshore structures,A new methodbased on counterpropagation neural networks(CPN)is proposed in this paper to predict the ultimate compres-sive strength of stiffened panels.Compared with two-parametric polynomial,this method can take more pa-rameters into account and make more use of experimental data.Numerical study is carried out to verify thevalidation of this method.The new method may find wide application in practical design.  相似文献   

Scientific Train of Thought and Methodological Innovation in the Intelligent Decision Support System for Earthquake Prediction in China     

Wang Chengmin  Zhou Shengkui  Zhao Yi  Wang Wei  Chen Ronghua  Xu Daoyi  Ma Li  Huang Wei  and Geng JunjunCenter for Analysis  Prediction  CSB  Beijing  China SeismoIogical Bureau of Heilongjiang Province  Harbin  China Seismological Bureau of Shanghai Municipality  Shanghai  China Institute of Geology  CSB  Beijing  China 《中国地震研究》1999,(3)

The level of present understanding of earthquake prediction of seismologists at home and abroad is very different. This is because China has opened up a special path of earthquake prediction research that has not been explored by other countries, with its own advantages and potentialities.Therefore, we considered that it is the most practical way to use the advantages and potentialities for raising the earthquake prediction level. For this purpose, we have developed a set of intelligent decision support system for earthquake prediction, with the analysis of cluster anomalies process at the core. The facts show that it can obviously raise the level of synthetic earthquake prediction.  相似文献   

Dynamic Plastic Response of Circular Plates Resting on Fluid with Finite Deformation     

Wang Gang  Li Zhen  Chen Tieyun Ph. D.  Marine Design  Research Institute of China  Shanghai Engineer  Marine Design  Research Institute of China  Shanghai Professor  Dept. of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1998,(1)

This paper concerns the dynamic plastic response of a circular plate resting on fluid subjectedto a uniformly distributed rectangular load pulse with finite deformation.It is assumed that the fluid isincompressible and inviscous,and the plate is made of rigid-plastic material and simply supported along itsedge.By using the method of the Hankel integral transformation,the nonuniform fluid resistance is de-rived as the plate and the fluid is coupled.Finally,an analytic solution for a circular plate under a mediumload is obtained according to the equations of motion of the plate with finite deformation.  相似文献   

An Experimental Investigation on Wave Loading on a Platform Mat     

Miao Guoping  Yao Meiwang  Zhang Chengyi  Ji Chunqun Professor  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Senior Engineer  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Engineer  School of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1998,(1)

Overall wave loading and local hydrodynamic pressure distributions on a platform mat in reg-ular waves for shallow waters are experimentally investigated in order to examine the severity of thenonlinear effects and shallow water effects.Wave focusing phenomenon is observed in the tests.The meas-ured results may also provide a comparison basis for the theoretical development to consider the nonlinearinteraction between waves and viscous flow by introducing viscosity into wave theories.  相似文献   

Nonlinear Capillary-Gravity Waves Produced by a Vertically Oscillating Plate     

Philip L.-F.LIU 《中国海洋工程》1998,(2)

The nonlinear capillary-gravity wave produced by a vertically oscillating plate,in which thecontact-angle model is considered,is studied by use of the Boundary Integral Equation Method(BIEM).The present numerical experiment shows that the code is robust and efficient for modeling the generationand propagation of capillary-gravity waves.It is found that the wave heights of stationary periodicnonlinear waves radiated away from the plate are dependent on the parameters involved in the contact-an-gle model.The effect of the contact-angle hysteresis and the nonlinearity of capillary-gravity waves on thewave profile is discussed in the paper.  相似文献   

船体结构腐蚀检测规划的成本及效益分析     

李典庆唐文勇  张圣坤 《海洋工程》2004,22(4):67-72

建立了基于风险的船体结构腐蚀优化检测规划的成本-效益分析模型。以费效比作为选择最优检测策略的标准,最优的检测策略是在保证结构设计工作寿命期内的可靠指标大于最低可靠指标的基础上,使得结构生命周期内总的费效比最大。在此基础上,以受点腐蚀损伤的船体构件为例,对其检测策略进行了成本-效益评估,并对计算结果进行了敏感性分析。结果表明,基于风险的成本及效益分析方法可以将检测规划的经济性和可靠性有效地结合起来,能够在风险与成本之间达到一种平衡,它在优化检测策略时是有效的。  相似文献