中丹水平子午环DCMT光栏的自动控制

本文指出了子午环光栏自动控制系统研制的必要性，并简要介绍了控制原理．结果表明，该控制部分设计合理大大简便了操作．     

Limits to the muon flux from neutralino annihilations in the Sun with the AMANDA detector

A search for an excess of muon–neutrinos from neutralino annihilations in the Sun has been performed with the AMANDA-II neutrino detector using data collected in 143.7 days of live-time in 2001. No excess over the expected atmospheric neutrino background has been observed. An upper limit at 90% confidence level has been obtained on the annihilation rate of captured neutralinos in the Sun, as well as the corresponding muon flux limit at the Earth, both as functions of the neutralino mass in the range 100–5000 GeV.     

Neutral hydrogen in the Galaxy and the galactic shocks

The effect of the differential rotation on the statistical behaviour of a dynamical system has been studied in the presence of a scalar field. The existence of neutrally stable regimes in a disk-like system has been shown which formally correspond to the Landau levels of a charged particle whose motion is quantized in a magnetic field. The existence also of the so-called anomalous Doppler effect has been pointed out, and a modified form is given to include the differential rotation. Finally, quantitative results are given concerning the instability of the system.     

Recent progress on the Columbus Project and the Miror Laboratory program

This paper summarizes recent advances on the Columbus Project telescope and in the University of Arizona Mirror Lab. The Columbus telescope structure has been re-optimized to allow rapid changes between foci, while still maintaining high rigidity. Room has been made to translate secondary and tertiary spiders out of the light path to the center. A bill allowing construction of the telescope on Mt. Graham, Arizona, has been passed by Congress and signed into law. Two alternative enclosure designs, one with a co-rotating building and a second which opens like a flower, are being explored.A common baseline design for the 8 m honeycomb mirrors for both the Columbus and Magellan telescopes has been developed. It has stiffness comparable to that of the Palomar 200 inch mirror. The Mirror Lab has successfully cast two 3.5 m honeycomb blanks and expects to begin casting at the 6.5 and 8 m scale at the end of 1990. Interferometric tests of the Vatican f/1 1.8 m borosilicate honeycomb mirror show good stability of figure with the air jet ventilation system. A 60 cm stressed lap has been completed, and will be used to parabolize this mirror which is now polished as an f/1 sphere. Plans for a polishing facility to house two 8 m machines and a test tower are complete, with construction starting in April 1989.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.     

A Statistical Study of the Relation between the Amplitude of Solar Cycle and the Area of Active Regions

Based on the observational data of sunspots, the relation between the amplitude of solar cycle and the total area of all active regions occurred in a solar cycle has been investigated. The result shows that the amplitude of solar cycle has a good correlation with the total area of all active regions occurred in the solar cycle. The relation between the amplitude of solar cycle and the area of the largest active region during a solar cycle has also been investigated. The result shows that the amplitude of solar cycle has a poor correlation with the area of the largest active region during a solar cycle, and there is no fixed relation between the peak time of a solar cycle and the time when the largest active region occurred in the solar cycle.     

On the effect of the distribution function of the injected or formed relativistic particles on the frequency spectra of the radio sources

In the present paper a model of the cosmic radio source with plasma, relativistic electrons and chaotic magnetic fields is considered. It is assumed that the energy changes of relativistic electrons which are due to spontaneous scattering on the transverse and Langmuir plasmons take place in this radio source. For such a radio source the kinetic equation has been solved in the presence of the injected or formed secondary electrons and the frequency spectrum has been obtained.     

Igneous vs impact processes for the origin of the mare lavas

In spite of chemical and petrological data furnished by the early Apollo missions, disagreement has persisted as to the ultimate origin of the mare lavas - were they true igneous magmas or impact melts? Examination of Lunar Orbiter and Apollo photographs of Tsiolkovsky, Mare Orientale and Humboldt crater, as examples of mare-filled impact structures, has suggested the answer. It has been found that the mare lavas possibly stem from internal melting because a considerable time interval has elapsed between the time of basin excavation and basaltic extrusions. This was most effectively shown by crater counts on the ejecta blanket and mare filling of Mare Orientale. The central mare filling is distinctly younger than the ejecta cover, as shown by the lower crater densities on the mare surface as compared with the ejecta. Furthermore, many craters on the ejecta blanket of Orientale were flooded by lava long after the impact had occurred. Mare-type lavas are not only confined to large circular impact basins, but also fill irregular depressions, like Mare Australe, where evidence for different flooding episodes has been observed.     

标准大气模型建立映射函数的可靠性讨论

随着新空间技术观测精度的不断提高，大气传播误差的研究已经成为改进观测精度的主要途径之一．为了提高大气延迟改正映射函数的计算精度，在大气剖面的选取上，近年来已经开始从过去的模型大气，逐渐地向实测大气转变．结合个别具有代表性的探空气球站观测资料，比较用标准大气模型建立的映射函数与探空气球资料路径积分的结果，研究用标准大气模型建立映射函数的可靠性，并简单讨论在映射函数中地球物理参数选择的若干问题．     

On the semiconvective zone in the core-helium-burning stars

The validity of current ideas to set up the semiconvective zone of the stellar models in corehelium-burning phase has been considered mainly from the view point of times-cales related to the mechanism. The time-scale of outward motion of convective shell has been estimated as being longer than that of evolution. From this point of view, it might be said that the models constructed with semiconvective zone are not appropriate for the core-helium-burning stars.     

Energy interconnection between the plasma cloud ejected from the active region and the shock wave

The relation between the ejected plasma cloud and the shock wave propagating ahead of it is examined for 27 pairs of such events. The flare sprays and the eruptive prominences observed in H line as well as the fast-moving sources of type-IV radio bursts have been considered as such ejected plasma clouds. Propagation of the shock wave in the solar corona has been examined from the observations of type-II radio bursts. Using the Parker model of the propagation of a shock wave, the shock wave velocity has been compared with the plasma cloud velocity. Energy interconnection between these two events has been studied. In the majority of the investigated cases there exists an energetic interconnection between the plasma cloud and the shock wave.     

Search for Evolutionary Changes in the Period of the Classical Cepheid CE Pup

Astronomy Letters - The reduction of all the available photometry for the Cepheid CE Pup has allowed its $$O-C$$ diagram spanning a time interval of 128 years to be constructed. This has made it...     

Dissipative structures in the F-region of the equatorial ionosphere generated by Rayleigh-Taylor instability

The non-linear regime of electrostatic perturbations of the equatorial ionospheric F-region generated by Rayleigh-Taylor instability has been discussed, taking into account conductivity along magnetic field lines. A closed non-linear equation has been derived in the stationary limit for the polarization electric field potential. It coincides with the Karman equation of an ideal liquid. To solve the equation, the averaged variational Whitham method has been proposed. Some solutions localized along and across the geomagnetic field, B, as well as quasi-periodic solutions in the transverse direction, have been investigated. Non-linear longitudinal localization of perturbations has been shown to be due to electron-ion collisions.     

Search for Evolutionary Changes in the Period of the Classical Cepheid EV Aql

Astronomy Letters - The reduction of all the available photometry for the Cepheid EV Aql has allowed its $$O-C$$ diagram spanning a time interval of 130 years to be constructed. This has made it...     

Statistical considerations in the analysis of solar oscillation data by the superposed epoch method

Solar Physics - Although the method of superposed epochs (Chree analysis) has been utilized for seven decades, a procedure to determine the statistical significance of the results has not been...     

Analysis of the Systematic Differences between the Stellar Parallaxes of the TGAS and Hipparcos Catalogues Using Spherical Harmonics

The systematic differences between the trigonometric parallaxes of the Hipparcos and TGAS catalogues have been investigated using spherical harmonics. The most significant harmonics in the expansion have been determined. The distribution of the parallax difference dispersion in various regions of the celestial sphere has also been studied. The distribution of the rms deviation has the simplest form in the ecliptic coordinate system.     

Some aspects of the solar radiation incident at the top of the atmospheres of Mercury and Venus

A formalism has been developed for the calculation of the insolation on the planets Mercury and Venus neglecting any atmospheric absorption. For Mercury, the instantaneous insolation curves are repeated in a 2-tropical year cycle, the distribution of the solar radiation being perfectly symmetric between both hemispheres. In addition to latitudinal variations, one observes a longitudinal effect expressed by different instantaneous insolation distributions during the course of the time; on the equator, the relative diurnal insolation variability may attain a factor of 3. The small obliquity of Venus results in a nearly symmetric solar radiation distributions with respect to the equator except at the poles, where an important seasonal effect has been found. It has to be noted that no longitudinal dependence exists. Finally, the insolation curves are repeated in a nearly half-year cycle.     

XEUS: the physics of the hot evolving universe

This paper describes the next generation X-ray observatory XEUS which has been submitted to the European Space Agency in the framework of the Cosmic Vision 2015–2025 competition and has been selected for an assessment study. The paper summarizes the scientific goals and instrumental concepts of the proposed X-ray telescope with 5 m² effective area and angular resolution better than 5 arc sec.     

银盘外区的翘曲结构

银盘外区存在翘曲结构和近边增厚现象已是不争的观测事实.自20世纪50年代通过中性氢的射电观测发现此类结构以来,对不同示踪天体(包括各类星族1天体、分子云、星际尘埃、老年恒星等)的观测都确认了这一重要发现.关于翘曲结构已提出若干形成机制,但尚未达成共识.     

Corrections to the Cardy-Verlinde formula at the Planck scale

The possible corrections to the thermodynamic quantities of higher dimensional Schwa-rzschild black hole have been investigated by considering the generalized uncertainty principle (GUP) and the modified dispersion relation (MDR) separately. The quantum gravitational corrections to the Hawking temperature, energy and entropy of the black hole have been calculated based on both the GUP and the MDR analysis. The explicit form of the corrections are worked out up to the sixth power of the Planck length. The impacts of GUP and MDR have been used separately to obtain the quantum gravitational corrections to the Cardy-Verlinde (C-V) formula. It has been shown that the usual C-V entropy formula receives some new corrections. Also the renormalized form of the C-V formula has been introduced by redefining Virasoro operator and central charge within both the GUP and the MDR. Through comparison of the corrections obtained from GUP and MDR approaches it has been found that the results of these two alternative approaches should be identical if one uses the suitable expansion coefficients.     

Periodicities and asymmetry of the jovian activity in the equatorial region

The atmospheric activity in the equatorial region of Jupiter, approximately in the zone between the zenocentric latitude ±12° has been studied during the period 1963-1967 by computing the photometric coefficient of activity.A north-south asymmetry has been found. Different periodicities of the activity for zones of different latitudes are found.