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1.
The orbits of 12 Trojan asteroids, which have Lyapunov times T
L105 years and were previously classified as ASCs(=asteroids in stable chaos), are integrated for 50 Myrs, along with a group of neighbouring initial conditions for each nominal orbit. About 40% of the orbits present strong instabilities in the inclination, which may be attributed primarily to the action of the 16 secular resonance; two escapes are also recorded. Higher-order secular resonances, involving the nodes of the outer planets, are also found to be responsible for chaotic motion. Orbital stability depends critically on the choice of initial conditions and, thus, these objects can be regarded as being on the edge of strong chaos. 相似文献
2.
Electron screening has strong effects on electron energy and threshold energy of the beta decay reaction.In this paper,we study β~-decay rates of some iron isotopes.The beta decay rates increase by about two orders of magnitude due to electron screening.Strongly screened beta decay rates due to Q-value correction are more than one order of magnitude higher than those without Q-value correction. 相似文献
3.
On the seventh of August 1912, from the measurements upon his seventh balloon ride that had taken him up to an altitude of 5.350 m, Victor Franz (Francis) Hess (1883–1864) discovered the cosmic radiation. His colleagues having continued casting doubts on the existence of such extra-terrestrial impingement for many years, the Austrian scientist was awarded the Nobel Prize for Physics in 1936 only. Victor F. Hess’ discovery opened novel fields of research with topics challenging until today. Hess was teaching physics at the Universities of Vienna, Graz, Innsbruck and, from 1938 onwards, of Fordham, New York, and all his life long continued being true to ‘his’ topic. Suffering himself of radium burns, Hess pioneered to install the first routine measurements of radium poisoning in the USA. 相似文献
4.
The Extreme ultraviolet SpectroPhotometer (ESP) is one of five channels of the Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO). The ESP channel design is based on a highly stable diffraction transmission grating and is an advanced version of the Solar Extreme ultraviolet Monitor (SEM), which has been successfully observing solar irradiance onboard the Solar and Heliospheric Observatory (SOHO) since December 1995. ESP is designed to measure solar Extreme UltraViolet (EUV) irradiance in four first-order bands of the diffraction grating centered around 19 nm, 25 nm, 30 nm, and 36 nm, and in a soft X-ray band from 0.1 to 7.0?nm in?the?zeroth-order of the grating. Each band’s detector system converts the photo-current into a count rate (frequency). The count rates are integrated over 0.25-second increments and transmitted to the EVE Science and Operations Center for data processing. An algorithm for converting the measured count rates into solar irradiance and the ESP calibration parameters are described. The ESP pre-flight calibration was performed at the Synchrotron Ultraviolet Radiation Facility of the National Institute of Standards and Technology. Calibration parameters were used to calculate absolute solar irradiance from the sounding-rocket flight measurements on 14 April 2008. These irradiances for the ESP bands closely match the irradiance determined for two other EUV channels flown simultaneously: EVE’s Multiple EUV Grating Spectrograph (MEGS) and SOHO’s Charge, Element and Isotope Analysis System/Solar EUV Monitor (CELIAS/SEM). 相似文献
5.
The Imaging Magnetograph eXperiment (IMaX) for?the?Sunrise Balloon-Borne Solar Observatory 总被引：1，自引：0，他引：1
V. Mart��nez?Pillet J. C. del Toro Iniesta A. ��lvarez-Herrero V. Domingo J. A. Bonet L. Gonz��lez?Fern��ndez A. L��pez?Jim��nez C. Pastor J. L. Gasent?Blesa P. Mellado J. Piqueras B. Aparicio M. Balaguer E. Ballesteros T. Belenguer L. R. Bellot?Rubio T. Berkefeld M. Collados W. Deutsch A. Feller F. Girela B. Grauf R. L. Heredero M. Herranz J. M. Jer��nimo H. Laguna R. Meller M. Men��ndez R. Morales D. Orozco?Su��rez G. Ramos M. Reina J. L. Ramos P. Rodr��guez A. S��nchez N. Uribe-Patarroyo P. Barthol A. Gandorfer M. Knoelker W. Schmidt S. K. Solanki S. Vargas?Dom��nguez 《Solar physics》2011,268(1):57-102
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne solar observatory in June 2009 for almost six days over the Arctic Circle. As a polarimeter, IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual-beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mÅ. IMaX uses the high-Zeeman-sensitive line of Fe i at 5250.2 Å and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15??C?0.18 arcsec range over a 50×50 arcsec field of view. Time cadences vary between 10 and 33 s, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are 4 G for longitudinal fields and 80 G for transverse fields per wavelength sample. The line-of-sight velocities are estimated with statistical errors of the order of 5??C?40 m?s?1. The design, calibration, and integration phases of the instrument, together with the implemented data reduction scheme, are described in some detail. 相似文献
6.
国际地球自转联测(MERIT)国内总结会于1985年6月1日至4日在上海天文台举行。参加总结会的除国内各主要天文台站、南大天文系等单位的代表外,还邀请了国内测绘界的部分专家、同行共33人出席了会议,其中正式代表31人,列席代表2人。 总结会进行了以下内容:(1)MERIT参加单位汇报观测项目情况;(2)资料分析中心汇报全球资 相似文献
7.
A. Eff-Darwich S.G. Korzennik T. Roca Cortés F. Pérez Hernández P. Pallé 《Astrophysics and Space Science》1998,263(1-4):347-350
In recent years, the capability to detect and analyse solar oscillation acoustic modes has greatly improved. The development
of ground based networks like GONG or BiSON and the use of space platforms like SOHO has allowed us to study the structure
and dynamics of the Sun with unprecedented precision.
In this work we explore the distribution of the rotation in the solar interior, specially in the core. This kind of information
is essential in order to study the physical processes involved in the evolution of the Sun and many other stars.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
In order to make an in-depth comparison between theory and observations, we analyse the light and velocity curves of various hydrodynamical models simulating RRab stars. The observations are represented by empirical formulae, derived in this and our earlier papers. It is shown that the overwhelming majority of the models tested do not follow the empirical relations regarding the shape of the light curves and the physical parameters. In almost all cases the luminosities predicted from the model light curves are significantly lower than the corresponding model values. The overall discrepancy of the models is an important indication of the limitation of the applicability of the present theoretical light and velocity curves in the determination of the physical parameters of these stars. In transforming the theoretical data to the observed light curves in V colour and in computing the observed radial velocities, it is shown that both bolometric correction and tracing the line-forming regions have considerable effects on the evaluation of the observed quantities. In an effort to resolve the discrepancy between theory and observations, it is suggested that a proper evaluation of the bolometric correction and radial velocity based on complete dynamical atmosphere models may be a useful step in this direction. 相似文献
9.
N. Hurlburt M. Cheung C. Schrijver L. Chang S. Freeland S. Green C. Heck A. Jaffey A. Kobashi D. Schiff J. Serafin R. Seguin G. Slater A. Somani R. Timmons 《Solar physics》2012,275(1-2):67-78
The immense volume of data generated by the suite of instruments on the Solar Dynamics Observatory (SDO) requires new tools for efficient identifying and accessing data that is most relevant for research. We have developed the Heliophysics Events Knowledgebase (HEK) to fill this need. The HEK system combines automated data mining using feature-detection methods and high-performance visualization systems for data markup. In addition, web services and clients are provided for searching the resulting metadata, reviewing results, and efficiently accessing the data. We review these components and present examples of their use with SDO data. 相似文献
10.
中国天文学会图书情报委员会主持召开的第一次图书情报学术交流会于1983年5月24日至28日在昆明举行。 全国天文界中有十五个单位的图书情报部门的代表和科研人员代表参加了会议。 长期从事天文学科图书情报工作的一些老同志,结合自已的工作经验,就书刊管理和资料交换等 相似文献
11.
桑塔克鲁兹位于旧金山市之南约100公里处。加利福尼亚大学的一个分校就建在这山峦起伏的绿树丛中。里克天文台离此不远。这里有一个著名的活动星系核研究小组,加上今年是里克天文台建立一百周年,使得这次国际学术会议特别隆重而有意义。参加这次会议的代表共有235名,来自23个国家。代表中有33名研究生,几乎每人都有报告。会上展示了116个张贴报告,进行了66个口头报告。其中有8 相似文献
12.
1986年8月25—31日,第一次全国恒星和行星物理学术讨论会在贵阳召开。会议由中国天文学会恒星和行星物理委员会负责组织和主持,得到了全国各有关天文台和大专院校的热情支持。出席会议的有十四个单位的六十五位代表,共宣读学术论文、综合评述和调研报告四十篇,内容涉及恒星的形成和演化,恒星风,恒星角直径、光度、光谱、偏振及同位素谱的观测研究,双星和星团,变星,天体 相似文献
13.
理论天体物理学术讨论会于1983年8月22—28日在新疆乌鲁木齐市昆仑宾馆召开。这个会议是由中国天文学会“高能天体物理”和“星系与宇宙学”两个专业委员会联合召开的。会前,于8月15日—21日,还由这两个专业委员会举办了一期宇宙学暑期讲习班。 参加宇宙学暑期讲习班的有来自全国各地的专业工作者三十余人。这次讲习班由方励之作了宇宙 相似文献
14.
由中国天文学会射电天文专业委员会主持召开的全国射电天文学术会议于一九八三年九月二日至八日在北京大学举行。来自全国有关十一个单位四十一名正式代表参加了会议。中国科学院数理学部副主任、北京天文台台长王绶琯同志,北京大学地球物理系系主任谢炎同志到会讲话,祝贺会议召开。 相似文献
15.
Nadjinangar Gotoum Christophe Nkem Kamel Hammami M. Ahamat?Charfadine L. C. Owono?Owono Nejm-Eddine Jaidane 《Astrophysics and Space Science》2011,332(1):209-217
We report on the calculation of collision induced rotational excitation cross sections and rate coefficients of AlF by He
atom at low temperature. These quantities were obtained by first computing the interaction potential energy surface (PES)
of the AlF(X
1Σ+)-He(1
S) van der Waals complex at the ab initio Coupled Cluster with Single and Double and perturbative Triple excitations [CCSD(T)] level of theory. The aug-cc-pVQZ Gaussian
basis, to which was added a set of bond functions, was used for that purpose. The calculations account for basis set superposition
errors (BSSE). The interaction potential presents a minimum of ∼24 cm−1 below the AlF-He dissociation limit. The PES was fitted on a basis of Legendre polynomial functions to allow for the calculation
of cross sections in the close-coupling (CC) approach. By averaging these cross sections over a Maxwell-Boltzmann velocity
distribution, rate coefficients were inferred at low temperatures (T≤300 K). From our computations, a propensity towards ΔJ=1 transitions is observed. 相似文献
16.
R. A. Hock P. C. Chamberlin T. N. Woods D. Crotser F. G. Eparvier D. L. Woodraska E. C. Woods 《Solar physics》2012,275(1-2):145-178
The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2010, incorporates a suite of instruments including the Extreme Ultraviolet Variability Experiment (EVE). EVE has multiple instruments including the Multiple Extreme ultraviolet Grating Spectrographs (MEGS) A, B, and P instruments, the Solar Aspect Monitor (SAM), and the Extreme ultraviolet SpectroPhotometer (ESP). The radiometric calibration of EVE, necessary to convert the instrument counts to physical units, was performed at the National Institute of Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF III) located in Gaithersburg, Maryland. This paper presents the results and derived accuracy of this radiometric calibration for the MEGS A, B, P, and SAM instruments, while the calibration of the ESP instrument is addressed by Didkovsky et?al. (Solar Phys., 2010, doi: 10.1007/s11207-009-9485-8 ). In addition, solar measurements that were taken on 14 April 2008, during the NASA 36.240 sounding-rocket flight, are shown for the prototype EVE instruments. 相似文献
17.
经过全国太阳射电天文工作者的协力筹备,1985年4月15日至20日在南京南京大学召开了首届“太阳射电天文学术讨论会”,来自全国各天文台、站,各大学天文专业的30余名代表出席了会议,提出学术报告共21篇,会议就22周太阳活动峰年射电观测和1987年9月23日在国内开展日环食射电联合观测研究课题进行了学术论证,得出了一致同意的结论。 相似文献
18.
在90年代前夕,中国天文学会所属天文地球动力学、星表与天文常数,时间与频率专业委员会,于1989年12月2日—5日在陕西天文台联合召开了90年代天体测量讨论会。参加会议的有20个单位的代表115人,收到论文96篇,其中包括了综合评述和近期研究工作的进度,并讨论了90年代我国天体测量的发展前景,集思广益提出了90年代中能与国际竞争的研究课题。会议有各方面专家参加,因此交叉学科的课题得到了深入的讨论。 相似文献
19.
中国天文学会太阳物理和日地关系专业委员会发起并组织的《太阳活动区物理》学术讨论会于1989年10月25—30日在四川省峨眉山市举行。会议得到。国家自然科学基金重大项目《太阳活动和宇宙活动天体研究》、中国科学院重点课题《第22太阳活动周峰年日地整体行为研究》和中国科学院天文委员会太阳分支学科的大力赞助。太阳射电爆发高时间分辨第二次学术工作研讨会和CSGD太阳耀斑资料会同时举行。中 相似文献
20.
1983年9月12日至18日在北京天文台连营寨观测站(河北省兴隆县境内)举行了“双星动力学”学术讨论班。参加这次讨论班的有紫金山天文台、上海天文台、云南天文台、南京大学天文系、北京师范大学天文系、北京天文台等六个单位的36名科技人员。 这次讨论班上宣读的文章或工作报告共16篇, 相似文献