The einstein observatory: new perspectives in astronomy

High-sensitivity x-ray measurements with the recently launched Einstein Observatory are having a major impact on wide areas of astronomical research. The x-ray luminosity of young O, B, and A stars and late K and M stars is found to be several orders of magnitude greater than predicted by current theories of coronal heating. Detailed x-ray images and spectra of supernova remnants are providing new information on the temperature, composition, and distribution of material ejected in supernova explosions as well as of the material comprising the interstellar medium. Observations of galaxies are yielding insights on the formation and evolution of stellar systems and galaxies over a wide range of variables. X-ray time variations are being used to probe the underlying energy source in quasars and active galactic nuclei. The distribution of mass in clusters of galaxies is being traced through detailed x-ray images, and the data are being used to classify clusters and trace their formation and evolution. Substantial progress is being made in several areas of cosmological research, particularly in the study of the diffuse x-ray background.     

Styles of volcanism on venus: new arecibo high resolution radar data

Arecibo high-resolution (1.5 to 2 km) radar data of Venus for the area extending from Beta Regio to western Eisila Regio provide strong evidence that the mountains in Beta and Eisila Regiones and plains in and adjacent to Guinevere Planitia are of volcanic origin. Recognized styles of volcanism include large volcanic edifices on the Beta and Eisila rises related to regional structural trends, plains with multiple source vents and a mottled appearance due to the ponding of volcanic flows, and plains with bright features surrounded by extensive quasi-circular radar-dark halos. The high density of volcanic vents in the plains suggests that heat loss by abundant and widely distributed plains volcanism may be more significant than previously recognized. The low density of impact craters greater than 15 km in diameter in this region compared to the average density for the higher northern latitudes suggests that the plains have a younger age.     

浅谈新升本科院校图书馆的目标定位与建设原则

本文论述了新升本科院校图书馆如何科学定位、确立发展建设原则等内容。     

The caracol tower at chichen itza: an ancient astronomical observatory?

Although our investigations reveal a number of significant astronomical events coinciding with many of the measured alignments presented in Table 1, not every alignment appears to have an astronomical match which we can recognize. It may be that only some of the sighting possibilities we have discussed were actually functional. Moreover, our search of significant astronomical events to match the alignments has included only those which seem of obvious functional importance to us: sun, moon, and planetary extremes and the setting positions of the brightest stars. We have emphasized those celestial bodies which are documented in the literature as having been of importance. Perhaps hitherto unrecognized constellations were sighted in the windows, perhaps fainter stars, the heliacal rising and setting times of which could have served to mark important dates in the calendar. While we propose no grand cosmic scheme for the astronomical design of the Caracol it can be inferred that the building, apart from being a monument related to Quetzalcoatl, was erected primarily for the purpose of embodying in its architecture certain significant astronomical event alignments, in the same sense that a modern astronomical ephemeris exhibits information of importance to us in the keeping of the current calendar. There are examples in the Mesoamerican historical literature of deliberate attempts to align buildings with astronomical directions of importance. For example, Maudslay (33) quotes Father Motolinia, who tells us that in Tenochtitlan the festival called Tlacaxipeualistli "took place when the sun stood in the middle of Huicholobos, which was at the equinox, and because it was a little out of the straight, Montezuma wished to pull it down and set it right." According to Maudslay, worshipers were probably facing east to watch the sun rise between the two oratories on the Great Temple of Tenochtitlan at the time of the equinox. The directions of the faces of the Lower and Upper platforms of the Caracol seem to have been laid out deliberately to point to horizon events involving the sun and the planet Venus. Of the lines taken through the windows, the Venus setting points seem most plausible to us in view of both the accuracy with which they fit the architecture and the historical evidence bearing upon the importance of Venus to the Mesoamerican people. A specific connection between the Venus calendar in the Dresden Codex and the sighting of the extreme positions of the planet along the horizon, however, is yet to be established. It is especially significant that alignments in both the base and the top of the tower relate to Venus. The solar equinox alignment in window I remains problematical, although the arrangement probably functioned as an approximate means of determining the first day of spring and the first day of autumn. Lines pointing to individual bright stars undoubtedly should be given lower value. If one is willing to carry the matching game to its ultimate completion, a stellar object can always be found which, although very obscure, will fit an alignment. In our consideration of the problem we have attempted to single out bright stars which appeared or disappeared on significant calendar dates. Other round structures resembling the Caracol exist in Mesoamerica (20), although there are comparatively few built by the Maya. Nearly all can be attributed to the cult of Quetzalcoatl (34). To our knowledge none have been carefully measured and analyzed for astronomical orientations. The ruined tower Q-152 at Mayapan bore distinct similarities to the Caracol, both in shape and structure. It probably contained only a single doorway which faced west. Both structures possessed circular corridors. A circular tower is still standing at Paalmul on the coast of Quintana Roo north of Tulum. Pollock (20, p. 115) states that it has a single room in the turret. A window similar to No. I in the Caracol faces northwest, the same direction as the base of the front of the structure. It may be astronomically significant that the Yucatecan towers fronted in approximately the same direction. Andrews (34) reports the existence of a curious circular building located at Puerto Rico, Campeche, near Xpujil. His crosssectional view of the tower bears a close resemblance to Ruppert's sketch (6, figure 293) of a horizontal section taken through the windows remaining at the top of the Caracol. Hartung (12) has suggested a possible astronomical use for the Puerto Rico tower, but no analysis of the orientation of its "windows," which are much smaller than those of the Caracol, has yet been conducted. Other circular buildings are reported at Ake (20, p. 113) and Isla Cozumel (35, p. 557). We hope that future investigations of the remains of Yucatecan towers will shed further light upon the significance and use of the Caracol as an astronomical observatory.     

Chankillo: a 2300-year-old solar observatory in coastal Peru

The Thirteen Towers of Chankillo run north to south along a low ridge within a fourth-century B.C.E. ceremonial complex in north coastal Peru. From evident observing points within the adjacent buildings to the west and east, they formed an artificial toothed horizon that spanned-almost exactly-the annual rising and setting arcs of the Sun. The Chankillo towers thus provide evidence of early solar horizon observations and of the existence of sophisticated Sun cults, preceding the Sun pillars of Incaic Cusco by almost two millennia.     

试析武术课教学中动作观察法的分类及应用

在武术课教学过程中,教师通常都要做各个角度、各个位置的示范动作,然而学生在观察的过程中,往往抓不住所要观察的重点,因而大大影响了观察的效果。我们知道,每个人天生都有一定的观察能力,但观察人的动作乃是一项有待发展的复杂技能,尤其在武术教学中,学生的动作观察能力显得格外重要。但在目前的武术教学中,大多数教师没有重视正规观察方法的传授,因此,即使学生在观察时注意力高度集中,也不能高效率地领会教师的示范动作。动作观察法泛指对某一动作对象进行有目的、有计划的感知。掌握武术教学中的动作观察法旨在使教师的示范动作在学…     

Overview and initial results of the very long baseline interferometry space observatory programme

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.