分子外流源L1211中近红外HH天体的发现

报告分子外流源Ｌ１２１１ 中新发现的１２ 个近红外ＨＨ 天体．在Ｌ１２１１ 的～４’区域,取得了ＪＨＫ’宽带和Ｈ２ 　ｖ ＝ １０ 　Ｓ（１） 发射线窄带的近红外图像．分析表明,新探测到的许多红外源与浓密分子云物理成协,其中有２０ 多个源表现出典型的Ｔ Ｔａｕｒｉ 星、Ｈｅｒｂｉｇ Ａｅ／Ｂｅ星和原恒星的红外超．Ｌ１２１１ 中的ＩＲＡＳ点源没有被观测到,可能是更深地埋于分子云中．对红外观测和分子线观测消光估计的比较显示,小于２μｍ 的近红外观测还不足以揭示深埋于分子云的整个年轻星团．根据近红外ＨＨ 天体的形态分布和红外源性质,能进一步证认这些ＨＨ 天体的激发源．其结果表明,Ｌ１２１１ 分子云中具有多个红外源驱动的多个外流活动     

两个底片天区的依巴谷星自行

利用上海天文台佘山４０ 厘米折射望远镜拍摄的２ 个底片天区１５ 张照相底片上的３１ 次观测,以ＡＣＴ 星表作为初始参考星表,按中心重叠法进行归算处理,得到了１６ 颗依巴谷星和３８ 颗场星的高精度位置和自行结果,其中依巴谷星的赤经和赤纬标准误差的平均值分别为１０ ．５ ｍａｓ 和７ ．５ ｍａｓ,赤经自行和赤纬自行标准误差的平均值分别为０ ．７０ ｍａｓ／ｙｒ 和０ ．５９ ｍａｓ／ｙｒ     

TWO NEW CHONDRITE-FALLS IN JAPAN

In the summer of 1984, two meteorites fell in the northern part of Honshu, Japan; Aomori, at 1:50 p.m. on June 30, and Tomiya, at 1:35 p.m. on August 22. Coordinates of the falls of the Aomori and the Tomiya are at 140°47.1'E., 40°48.6'N., and 140°51.9'E., 38°22.0'N., respectively. Results of chemical analyses of major elements, ratios of Fe_total/SiO₂ (0.546 and 0.803) and Fe_metal/Fe_total (0.332 and 0.581), and molar compositions of olivines (Fa₂₅ and Fa₁₉) indicate that the Aomori and the Tomiya are typical L- and H-group ordinary chondrites, respectively. In the Aomori, chondrules are present as relicts in the well-recrystallized matrix. Olivine and pyroxene are homogeneous in composition, and coarse clear feldspar, up to 100 micrometers in size, is well developed in the chondrules and matrix. Though the Aomori is a petrologic type 6 based on its texture and mineralogy, it includes a few grains of multiple twinned clinobronzite which is rarely observed in highly equilibrated ordinary chondrites. In the Tomiya, chondrules possess a fine-grained mesostasis, and both orthopyroxene and clinobronzite are noticeable in thin sections. Plagioclase is mostly microcrystalline, but is also sparsely present as tiny, visible grains. Thus, the Tomiya was classified to be petrologic type between 4 and 5. The deformation texture of olivine, pyroxene and plagioclase indicates that both meteorites were shocked by 0.2-0.25 Mb. In conjunction with the discussion of the frequency of meteorite-falls, all observed falls of meteorites in Japan are tabulated in this paper.     

TWO COMPONENTS OF COSMIC-RAY MODULATION

The long-term modulation of galactic cosmic rays is investigated from 1957 up to 1992 analysing the dynamic and the quasi-stationary components, separately. It has been found that the dynamic component is characterized by the presence of two peaks at the maximum phase of each solar activity cycle. We infer that the time interval between the two peaks corresponds to a period (well-related to the polar heliomagnetic reversal) in which somewhat decreased activity occurs for intense and long-lasting solar events. In fact, a contemporary dip in the magnetic energy released from the Sun was observed, in agreement with the suggested double maximum displayed by the basic features of the 11-year solar-activity cycle (Gnevyshev, 1977, and references therein). Moreover, the dynamic component of cosmic-ray modulation often shows a multi-structured profile in both peaks of activity, fairly well-connected with the pattern of the green corona brightness. On the other hand, analysing the quasi-stationary long-term trend of cosmic-ray intensity we pick out a good relationship between periods of enhanced cosmic-ray modulation and the area expansion of coronal intensity levels. The relevance of our results for solar-terrestrial forecasting is underlined.     

两个相邻活动区中的相应耀斑

本文描述ＮＯＡＡ６２３３活动区中的一组双带耀斑及和与之有时间相关性的ＮＯＡＡ６２４０中的单带耀斑的磁场位形．并着重讨论由观测推断出的磁场拓扑联接性．分析表明：三个单耀斑发生在正极磁区里，与发生在δ黑子区中的双带耀斑，可能有远距离磁环相联系．这一高位磁环与δ黑子中的低位剪切磁环柑互作用，可能是能发双带耀斑的直接原因．在双带耀斑能量初始释放中被加速的电子，可能是沿着高位磁环或磁拓扑分界面（ＮＯＡＡ ６２４０与ＮＯＡＡ６２３３间）传播，并导致ＮＯＡＡ６２４０中的单带耀斑．因此这些单带耀斑都可能是双带耀斑的相应耀斑．     

THE PHOTOELECTRIC OBSERVATIONS OF TWO EVENTS OF OUTBURSTS OF COMET HALE-BOPP

Two events of outburst of Garnet Hale - Bopp occurred on Oct. 9,1996 and Nov. 13,1996 are observed by means of photoelectric integrating photometer mounted on the 60cm reflector of Purple Mountain Observatory. The results are shown in Tab. 3, Fig. 1 (Oct. 9, 1996) and in Tab.4,Fig.2(Nov.13,1996).     

PLAGIOCLASE TWIN LAWS IN LUNAR HIGHLAND ROCKS; POSSIBLE PETROGENETIC SIGNIFICANCE

Plagioclases in different types of lunar highland rocks (all highly feldspathic) are twinned according to different laws and in different styles. Carlsbad and Carlsbad-albite twins, presumed to be growth twins, occur mainly in rocks which show igneous texture, and which have not been severely brecciated. These two twin laws appear to be absent from cataclastic rocks, including cataclastic anorthosite, possibly because the original twins were preferentially broken up in cataclasis (the composition plane being a plane of weakness). Pericline and lamellar albite twins, presumed to be deformation twins (except for some albite growth twins) occur in all types of rocks, and obvious deformation features, such as bending of lamellae, are well shown in many cataclastic rocks. Surprisingly, some Carlsbad and Carlsbad-albite twins are found in rocks with granoblastic texture, which presumably recrystallized in the solid state. This contrasts with previous observations on terrestrial metamorphic rocks, in which such growth twins are scarce or absent. The difference may be due to a higher rate of temperature change in the shock-heated lunar rocks. Further study of plagioclase twin laws in lunar rocks may assist in deciphering the complicated history of the highlands.     

3-D MHD SIMULATION OF X-TYPE COALESCENCE OF TWO CURRENT-LOOPS

We present simulation results of X-type coalescence of two current-loops, by using a 3-D resistive MHD code. The results are compared with the limb flare observed by Yohkoh on 2 August, 1993 at 08:30 UT, which is a good example of partial X-type coalescence. It is shown that the maximum temperature enhancement near the cross-point of the two loops, obtained from the simulation, agrees well with the observations when the plasma is 0.08.     

两种观测技术综合精密定轨的探讨

利用T／P卫星的SLR和DORIS实测资料,对两种观测技术综合精密定轨中的加权及其对定轨影响的问题作了初步的探讨。根据所提出的一种经验性的加权方法进行了综合定轨计算,结果表明：对于两种不同技术的观测,相对权选取的恰当与否将影响综合定轨的精度;综合定轨的最优加权不仅依赖于观测资料的精度,还与观测资料的多少和几何分布有关;通过选用最优加权,可使得综合轨的精度优于仅用其中一种技术的定轨精度,综合定轨能有效地提高定轨精度。     

中国SLR流动站7343,7355地心站坐标的精密测定

主要介绍利用LAGEOS1卫星的全球激光测距资料精确测定我国的激光流动站 7343,735 5的地心坐标 ,并对观测资料作了精度分析 ,结果表明 :激光流动站站坐标测定精度达厘米级 ,激光流动站的观测精度约为 2cm。     

对两种GPS解算方案的残差统计检验评估

文[1]和[2]中提出根据拟合后剩余残差的统计检验来全面评估解算,其想法是除了一般采用的ＲＭＳ和协方差外还试图以更多的统计量来反映解算更细致的差别.将其应用于Ｌａｇｅｏｓ激光资料的处理,文[3]鉴别了具有相同ＲＭＳ水平而差异较大的不同解算.但是除了理论上的依据外,文[3]事实上未能表明其中残差分布较合理的解确实优于其余的情况.本文的目的之一是试图改进这一不足之处.采用由美国喷气推进实验室(ＪＰＬ)发展的ＧＰＳ数据处理软件ＧＩＰＳＹ,本文比较仅固定精密星历(ＦｉｘｅｄＰｒｅｃｉｓｅＯｒｂｉｔｓ,简称为ＦＰＯ)和同时固定精…     

EVALUATION OF TWO FRACTAL METHODS FOR MAGNETOGRAM IMAGE ANALYSIS

Fractal and multifractal techniques have been applied to various types of solar data to study the fractal properties of sunspots as well as the distribution of photospheric magnetic fields and the role of random motions on the solar surface in this distribution. Other research includes the investigation of changes in the fractal dimension as an indicator for solar flares. Here we evaluate the efficacy of two methods for determining the fractal dimension of an image data set: the Differential Box Counting scheme and a new method, the Jaenisch scheme. To determine the sensitivity of the techniques to changes in image complexity, various types of constructed images are analyzed. In addition, we apply this method to solar magnetogram data from Marshall Space Flight Center's vector magnetograph.     

一个黑子群“碰撞”和活动区复合的观测例子

本文和赣榆站所拍得的精细色球资料研究了１９９０年１０月两个活动区的复合过程，在缺少适时准确的磁图条件下，我们以Ｋｉｔｔ Ｐｅａｋ磁图为背景，巧妙运用Ｚｉｒｉｎ－Ｐｒａｔａ法则，剖析了此两区的发展过程。发现：１）所谓黑子群“碰撞”不仅包含了两黑子群因迁移运动逐渐相互靠拢、接触，还包含了新生磁流在两群边界处浮现生长以及原黑子的衰没，２）随着“碰撞”的发生，被“碰”黑子的磁流迅速衰减，这时在接触边界处，     

NATURAL THERMOLUMINESCENCE OF CALCAREOUS ROCKS FROM THE CHARLEVOIX (MALBAIE) STRUCTURE

The natural thermoluminescence of samples of limestone from within and near the Charlevoix meteorite impact structure indicates that the effect of impact, strain due to faulting, low grade thermal metamorphism, and recrystallization can often be distinguished on the basis of the shape and either the total emission or amplitude of the peaks of the thermoluminescence curves. Impact causes a reduction of thermoluminescence which is detectable in the Charlevoix structure for about 10 Km outside the known limits of shatter cone development. It is inferred that thermoluminescence investigations should provide a useful means of investigating other impact structures. Impact effects on quartz rich rocks appear to be somewhat similar to the effects in calcareous rocks, but a fundamental difference in the electronic properties of shocked quartz and calcite demonstrate that identical effects should not be anticipated.     

RXTE ASM的双SSC联合直接解调成像

利用直接解调成像方法对ＲＸＴＥ ＡＳＭ两个指向相同的扫描阴影照像机（ＳＳＣ）的观测,数据进行了联合成像分析,对Ｃｒａｂ天区的研究结果表明,联合成像对源的分辨能力比单ＳＳＣ成像有进上步提高,并且还对银心附近含多个源的一个天区进行了联合成像,分别计算了成像所得的３个Ｘ射线源的强度和位置坐标,并利用源与源之间的位置关系对ＲＸＴＥＡＳＭ定位定标中可能存在的系统误差作出估计,发现以直接解调成像法所得强源的定     

云南天文台丽江高美古和昆明的大气视宁度研究

研究云南天文台昆明凤凰山和丽江高美古两地点的大气视宁度。利用云南天文台于1994年建立的3孔较差视宁度监视仪（3孔DIMM），对这两个地点的视宁度对比观测。还利用云南天文台的1米望远镜所得到的视宁度与3孔DIMM所测的视宁度进行对比。1米望远镜和3孔DIMM同时观测了7个晚上，各取得308组数据，它们的视宁度平均分别为0．90〃和0．84〃。还讨论了3孔DIMM采用不同曝光时间对视宁度测量值的影响，从实验得出3孔DIMM采用20ms曝光比采用8ms曝光所测视宁度的值要好15％左右。从1995年5月－1996年12月，对丽江高美古和昆明凤凰山二地进行了视宁度的对比观测。在高美古和昆明分别观测了234夜和256夜，观测结果是两个点的视宁度平均；丽江为0．70〃，昆明为0．95〃，同时也统计了两个点的月平均视宁度和最好夜的视宁度，并讨论了两地视宁度随时间的变化规律。     

THE CORE OF THE QUADRANTID METEOROID STREAM IS TWO HUNDRED YEARS OLD

The Quadrantids are one of the most active annual meteor showers and have a number of unusual features. One is a sharp brief maximum, 12–14 h in length. A second is the Quadrantids, relatively recent appearance in our skies, the first observation having likely been made in 1835. Until recently no likely parent with a similar orbit had been observed and previous investigators concluded that the stream was quite old, with the stream’s recent appearance and sharp peak attributed to a recent fortuitous convergence of meteoroid orbits. The recent discovery of the near-Earth asteroid 2003 EH1 on an orbit very similar to that of the Quadrantids has almost certainly uncovered the parent body of this stream. From the simulations of the orbit of this body and of meteoroids released at intervals from it in the past, we find that both the sharp peak and recent appearance of the Quadrantids can most easily be explained assuming meteoroids were ejected in substantial numbers near 1800 AD.     

HIGH POSSIL AND STRATHMORE—A STUDY OF TWO L6 CHONDRITES

High Possil and Strathmore are the first (1804) and last (1917) meteorite falls, respectively, of the three recorded in Scotland. Olivine compositions and total Fe contents in High Possil (Fa_25.2; 21.35 wt %) and Strathmore (Fa_25.3; 20.6 wt %) confirm their classification as L-group chondrites (Mason, 1963), and the presence of abundant plagioclase feldspar shows that both chondrites belong to petrologic type 6. Both chondrites display thermal and mechanical alteration attributable to moderate shock-loading appropriate to facies c (High Possil) and c-d (Strathmore) (Dodd and Jarosewich, 1979). Incipient shock-melting of metal and troilite in both chondrites is the first described from Lc chondrites, and differences in the responses of metallic and silicate minerals to shock-loading are discussed.