检索结果-南通市图书馆

Geometry of Broad Line Regions of Active Galactic Nuclei

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 50-62页

作者： Xiao-Rong Lü1 key Laboratory for Particle Astrophysics, institute of High Energy Physics, {2., beijing 100049 2.Graduate School of {2., beijing 100049 key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 Graduate School of chinese academy of sciences Beijing 100049

It has long remained an open question as to the geometry of the broad line region （BLR） in active galactic nuclei （AGNs）. The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of probing the BLR geometry. We analyze a sample of 35 AGNs, which have been monitored by the reverberation mapping campaign. In view of energy budget, the reverberation-based BH masses are found to be in agreement with those obtained by accretion disk models in two thirds of the present sample while the reverberation mapping methods underestimate the BH masses in about one third of objects, as also suggested by CoUin et al. in a recent work. We point out that there are obviously two kinds of BLR geometry, which are strongly dependent on the Eddington ratio, and separated by the value LBol/LEdd - 0.1. These results prefer a scenario of the disk and wind configuration of the BLR and identify the Eddington ratio as the physical driver regulating the wind in the BLR.

关键词： accretion, accretion disks - galaxies active - galaxies Seyfert - quasars general

SOLID PHASE TRANSITION OF SYNDIOTACTIC POLYSTYRENE IN SUPERCRITICAL CO_2

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer science 2002年第3期20卷 191-196页

作者： Yu-ying Li Jia-song He state key Laboratory of Engineering Plastics, Center for Molecular {2., institute of Chemistry chinese academy of sciences, beijing 100080 china Center for Molecular science Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Engineering Plastics 北京 100080

Solid phase transition of the a form crystals to the 3 form crystals in syndiotactic polystyrene (sPS) samples has occurred in supercritical CO2. This transformation is different from those detected under other conditions. The effects of some factors (e.g. time, temperature, and pressure) on the solid phase transformation of sPS in supercritical CO2.were analyzed in detail. Experimental results show that longer time, higher temperature or higher pressure favors the transformation of the a form crystals to the beta form crystals.

关键词： solid phase transition syndiotactic polystyrene supercritical CO2

Leakproof secret sharing protocols with applications to group identification scheme

在线全文

学校读者我要写书评

暂无评论

science china(Information {2.) 2012年第5期55卷 1172-1185页

作者： TANG ChunMing 1,2.& GAO ShuHong 3 1 School of Mathematics and Information science,Guangzhou University,Guangzhou 510006,china {2. key Laboratory of Information Security,institute of software science,chinese academy of sciences,beijing 100049,china 3 Department of Mathematical sciences,Clemson University,SC 2.634,USA School of Mathematics and Information science Guangzhou University Guangzhou China state key Laboratory of Information Security Institute of Software Science Chinese Academy of Sciences Beijing China Department of Mathematical sciences Clemson University Clemson USA

In a traditional (t,n)-threshold secret sharing scheme,t or more honest participants can reconstruct the secret *** the reconstruction process,the individual shares and the secret key K are revealed,hence K is shared once *** this paper,we firstly give the definition of leakproof secret sharing scheme which is composed of a distribution protocol and a proof protocol,then propose two leakproof secret sharing protocols,a computationally secure protocol and an information-theoretically secure *** our protocols,t or more participants can jointly prove that they hold the secret K by using a multi-prover zero-knowledge argument of *** a result,the secret K will be shared for as many times as ***,each participant can detect the dealer in the distribution protocol from cheating,and any verifier can prevent non-qualified set of participants in proof protocol from *** an example of the practical impact of our work we use our techniques to construct group identification schemes with zero-knowledge.

关键词： secret sharing leakproof secret sharing multi-prover zero-knowledge argument proof of knowl-edge group identification scheme

A new trust region algorithm for image restoration

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Mathematics 2005年第2期48卷 169-184页

作者： WEN Zaiwen & WANG Yanfei state key Laboratory of Scientific Engineering Computing, {2. of Computational Mathematics and Scientific/Engineering Computing, academy of Mathematics and System sciences, chinese academy of sciences, beijing 100080, china National key Laboratory on Remote Sensing science, {2. of Remote Sensing Applications, chinese academy of sciences, beijing 100101, china state key Laboratory of Scientific Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China National key Laboratory on Remote Sensing science Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China

The image restoration problems play an important role in remote sensing and astronomical image analysis. One common method for the recovery of a true image from corrupted or blurred image is the least squares error (LSE) method. But the LSE method is unstable in practical applications. A popular way to overcome instability is the Tikhonov regularization. However, difficulties will encounter when adjusting the so-called regularization parameter a. Moreover, how to truncate the iteration at appropriate steps is also challenging. In this paper we use the trust region method to deal with the image restoration problem, meanwhile, the trust region subproblem is solved by the truncated Lanczos method and the preconditioned truncated Lanczos method. We also develop a fast algorithm for evaluating the Kronecker matrix-vector product when the matrix is banded. The trust region method is very stable and robust, and it has the nice property of updating the trust region automatically. This releases us from tedious finding the regularization parameters and truncation levels. Some numerical tests on remotely sensed images are given to show that the trust region method is promising.

关键词： trust region algorithm, image restoration, Lanczos method, Kronecker matrix-vector product, preconditioning.

Chronic morphine treatment decreases acoustic startle response and prepulse inhibition in rats

在线全文

学校读者我要写书评

暂无评论

science china(Life {2.) 2010年第11期53卷 1356-1360页

作者： MENG ZhiQiang1,3, ZHOU DongMing1,2. WANG JianHong1 & MA YuanYe1,2.1state key Laboratory of Brain and Cognitive {2., Kunming institute of Zoology, chinese academy of sciences, Kunming 6502.3, china 2.0} key Laboratory of Brain and Cognitive {2., institute of Biophysics, chinese academy of sciences, beijing 100101, china 3Graduate University of chinese academy of sciences, beijing 100049, china state key Laboratory of Brain and Cognitive {2. Kunming Institute of Zoology Chinese Academy of Sciences Kunming China Graduate University of chinese academy of sciences Beijing China state key Laboratory of Brain and Cognitive {2. Institute of Biophysics Chinese Academy of Sciences Beijing China

The reward-related effects of addictive drugs primarily act via the dopamine system, which also plays an important role in sensorimotor gating. The mesolimbic dopamine system is the common pathway of drug addiction and sensorimotor gating. However, the way in which addictive drugs affect sensorimotor gating is currently unclear. In previous studies, we examined the effects of morphine treatment on sensory gating in the hippocampus. The present study investigated the effects of morphine on sensorimotor gating in rats during chronic morphine treatment and withdrawal. Rats were examined during treatment with morphine for 10 successive days, followed by a withdrawal period. Acoustic startle responses to a single startle stimulus (115 dB SPL) and prepulse inhibition responses were recorded. The results showed that acoustic startle responses were attenuated during morphine treatment, but not during withdrawal. PPI was impaired in the last 2.morphine treatment days, but returned to a normal level during withdrawal.

关键词： morphine treatment sensorimotor gating startle response prepulse inhibition

Density functional theory study of the reaction paths of reactions of CH3C（O）O2.radicals with HO2.in the gas phase

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2006年第12期16卷 1269-1274页

作者： ZHOU Yuzhi~ 1,2., ZHANG Shaowen~1 and LI Qianshu~1**(1. state key Laboratory of Explosion {2. and Technology, beijing institute of Technology, beijing 100081, china 2. beijing institute of Education, beijing 100044, china) state key Laboratory of Explosion {2. and Technology Beijing Institute of Technology Beijing 100081 China beijing institute of Education Beijing 100044 China

A DFT study on the reactions between CH_3C（O）O_2.nd HO_2.adicals has been carried out. It is suggested that both the triplet and singlet potential surfaces involve a complex mechanism with the formation of loosely bound intermediate complexes of reactants and products. The reaction prefers to occur on the triplet surface to produce peracetic acid (CH_3C（O）O_2.) and triplet O_2.olecule. The CH_3C（O）O_2. can further convert into CH_3C（O）O and HO radicals.

关键词： acetyl peroxy radicals HO2.radicals reaction mechanism DFT.

Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Earth {2. 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2. DING Yihui3 & ZHANG Renhe2.1. Jiangsu key Laboratory of Meteorological Disaster (KLME), Nanjing institute of Meteorology, Nanjing University of Informa- tion {2. and Technology, Nanjing 2.0044, china 2. state key Laboratory of Severe Weather (LaSW), chinese academy of Meteorological sciences, beijing 100081, china 3. National Climate Center, chinese Meteorological Administration, beijing 100081, china Jiangsu key Laboratory of Meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing China state key Laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing China National Climate Center Chinese Meteorological Administration Beijing China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-china Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-china Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-china Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-china Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-china Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-china Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-china Peninsula to South china Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-china Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

Energy Transfer among Chlorophylls in Trimeric Light-harvesting Complex Ⅱ of Bryopsis corticulans

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2006年第5期38卷 310-317页

作者： Su-Juan ZHANG~(1,2.)Shui-Cai WANG~2.Jun-Fang HE~2.Hui CHEN~3 1 institute of Photonics and Photo-Technology,Northwest University,Xi'an 710069,china {2. key Laboratory of Transient Optics and Photonics,Xi 'an institute of Optics and Precision Mechanics,chinese academy of sciences,Xi'an 710068.china 3 Laboratoty of Photosynthesis Basic Research,institute of Botany,chinese academy of sciences,beijing 100093,china institute of Photonics and Photo-Technology Northwest UniversityXi'an 710069 China state key Laboratory of Transient Optics and Photonics Xi'an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi'an 710068 China Laboratory of Photosynthesis Basic Research Institute of Botany Chinese Academy of SciencesBeijing 100093 China

A study on energy transfer among chlorophylls（Chls）in the trimeric unit of the major light-harvesting complex Ⅱ（LHC Ⅱ）from Bryopsis corriculan,was carried out using time-correlated singlephoton *** the chlorophyll Q region of LHC Ⅱ,six molecules characterized as Chlb62.,Chlb646,Chlb652.54,657,Chla664666,Chla674677.680and Chla682.83were discriminated according to their absorption spectrumand fluorescence emission ***,excited by pulsed light of 62. nm,fluorescence kinetics spectrain the chlorophyll Q region were *** accordance with the principles of fluorescence kinetics,thesekinetics data were analyzed with a multi-exponential *** constants on energy transfer were *** overwhelming percentage of energy transfer among chlorophylls undergoes a process longer than 97picoseconds（ps）,which shows that,before transferring energy to another Chl,the excited Chl might convertenergy to vibrations of a lower state with different multiplicity（intersystem crossing）.Energy transfer at thelevel of approximately 10 ps was also obtained,which was interpreted as the excited Chls may go throughinternal conversion before transferring energy to another *** with a higher standard deviation,timeconstants at the femtosecond level can not be entirely excluded,which can be attributed to the ultrafastprocess of direct energy *** to the arrangement and direction of the dipole moment of Chls inLHC Ⅱ,the probability of these processes is *** fluorescence lifetimes of Chlb652.54,657,Chla664666,Chla674677.680and Chla682.83were determined to be 1.44ns,1.43 ns,636 ps and 713 ps,*** of energy dissipation in the pathway of fluorescence emission were no more than 40% in thetrimeric unit of LHC Ⅱ.These results are important for a better understanding of the relationship between thestructure and function of LHC Ⅱ.

关键词： energy transfer LHC Ⅱ transient spectrum fluorescence kinetics

Paeonia rotundiloba(***)***:A new status in tree peonies(Paeoniaceae)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systematics and Evolution 2011年第5期49卷 464-467页

作者： De-Yuan HONG(state key Laboratory of Systematic and Evolutionary Botany,{2. of Botany,chinese academy of sciences,beijing 100093,china) (state key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China)

Paeonia decomposita Hand.-*** *** is here raised to the specific rank,***(***) ***,based on its distinctiveness of four diagnostic characters:number of carpels;height of disk;number of leaflets of the lower leaves,and shape of the terminal leaflets;and unpublished molecular *** rotundiloba differs distinctly from *** in having carpels mostly 3,less often 2.or 4,very rarely 5(*** always 5,very occasionally 4 or 3),disk 8-15 mm high(vs.4-9.6 mm),leaflets mostly 19-39(vs.2.-63) in number,and ratio of length to width of the terminal leaflets 1.09-1.93(vs.1.81-2.99).

关键词： china new status Paeonia decomposita Paeonia rotundiloba Sichuan statistical analysis.