A NEW MEASURE OF THE NICKEL CONTENT OF METEORITIC COPPER

A copper grain in the Mayfield chondrite surrounded by troilite contains up to 2.1% Ni. This provides a better measure of the Ni content in meteoritic Cu alloy than a former measurement which required a calculated correction for fluorescence effects from adjacent Fe-Ni alloy.     

视界问题的新图示(英文)

在用定义为径向距离除以尺度因子的径向坐标r和宇宙时间t的r-t图中,大爆炸时向我们发射、现在到达我们这里的光子的轨迹,r_(t),是大爆炸时我们向外发射光子轨迹,r+(t)的镜象。前者画出我们现今时刻的“世界图象”(world picture),而后者则描绘(粒子)视界自从大爆炸以来的增长。方程,r_(t)=～(1/2)r+(t)决定时刻t_D,它有如下性质:世界图象中凡早于t_D的事件多少都有视界问题,晚于t_D的事件就没有视界问题。 对于平直的Friedmann宇宙,算得t_D颇晚(相应的红移仅是z_D≈1.25!),远晚于微波背景辐射的时刻t_M(其红移为～10~3)。对于Guth的暴涨宇宙,算得t_D很接近暴涨期的开始,远早于t_M。 对于一个弯曲的Friedmann宇宙,Penrose图的时间轴可被证认为通常用来表述尺度因子演化的参数方程中的参数η,而其空间轴可被证认为径向角坐标x,由此马上得出:当哈勃时间H_0~(-1)=20×10~9年时,对于一个减速参数q_0=1.65的封闭宇宙,z_D=0.86;对于一个密度参数Q_0=0.05的开放宇宙,z_D=3.66。     

太阳高能观测技术

通常将太阳高能观测划分为三个能段,软Ｘ 射线能段（０ ．１ｋｅＶ～１０ｋｅＶ） ,Ｘ 射线及软γ射线能段（０ ．１ ＭｅＶ～１０ ＭｅＶ） ,γ射线能段（１ ＭｅＶ 以上） 。本文就各个能段的探测技术,包括成像系统和探测器,作了全面的调研,重点在新技术的应用。     

北京天文台60cm望远镜的新光电光度计

本文介绍了北京天文台新研制的光电光度计。本光度计是带有微计算机星天交替式的。可通过计算机控制实现星天和滤光片自动转换。可以很方便地进行随机采集和连续采集,可以实时显示数据和处理观测结果。已经正规观测两年多,取得了一批观测成果,精度可达±0.003~m,能很好地归化到国际系统。     

红外天文观测中望远镜副镜的一种新调制方法

本文介绍一种称作三位调制的望远镜副镜调制新方法。在用望远镜作L和M波段的红外天文观测时,采用这种新调制方法,在一定条件下可以替代望远镜所做的双束转换运动而获得令人满意的结果。对于控制功能不是很强的望远镜,或者进行一些不允许望远镜摆动的特殊观测(如红外偏振测量),这种方法极为有用。本文介绍了这种新调制方法原理和电路,并且使用1.2米红外望远镜比较了用这种新调制方法和用通常的副镜二位调制方法对一组红外标准星的测量结果:在J和K波段;两种方法的结果大体相同,在L波段,新调制方法显示出明显的优越性。     

综合评价线性多步积分公式轨道积分性能的两项新指标

概述了制约线性多步积分公式轨道积分状态的多种因素 ;提出了综合评价线性多步积分公式积分性能的两项新指标。建议在对数值计算有较高精度要求的科研项目中 ,应将构造并选择适合研究项目的线性多步积分公式以及高效的积分方式列为课题前期工作的重要部分     

13.7米望远镜用3mm振荡器恒温电路的改进

本文介绍了青海站 1 3.7米射电望远镜上 3mm振荡器恒温电路的改进情况。新的恒温电路有别于原来所使用的恒温电路的工作方式。实际使用证明 ,该电路性能可靠 ,显著提高了系统稳定性。     

γ爆的一种新模型

本文提出了关于γ爆的一种新模型，认为γ爆起源于老年中子星，老年中子星表面磁场包含两部分：一为弱的背景偶极磁场；另一为细管状局域强磁场，该模型可以同时解释γ爆能谱中回旋吸收线和高能尾巴的存在。本文用蒙特卡洛方法拟合了ＧＢ８８０２０５的能谱，与观测结构符合得比较好。     

CILIMUS: A NEW CHONDRITE FALL

Cilimus is a new Indonesian chondrite. Its mineralogy and chemistry categorize it as a veined, intermediate-to-white hypersthene or L-5 chondrite. Black veins and impact-produced glasses including maskelynite show evidence that Cilimus has been severely shocked.     

THE MILLS,NEW MEXICO,CHONDRITE — A NEW FIND

A mineralogical and chemical analysis has been performed on a slice of the Mills, New Mexico, chondrite, which was found in August 1970. The mineralogical composition is olivine Fa_19.5, bronzite, Fs_17.4, plagioclase, nickel-iron, troilite and ilmenite. The chemical analysis confirms that Mills is a typical bronzite, H5 chondrite, with considerable degree of weathering, as indicated by the presence of large amounts of Fe₂O₃. A comparison with other stones found in the same New Mexico region by Nininger may show a possible relation between Mills and previous finds.     

FLUX EMERGENCE AND PROMINENCES: A NEW SCENARIO FOR 3-DIMENSIONAL FIELD GEOMETRY BASED ON OBSERVATIONS WITH THE ADVANCED STOKES POLARIMETER

This paper presents an interpretation of the evolution of the vector magnetic field at the photosphere based on measurements of the advanced Stokes polarimeter, along with chromospheric H from the Lockheed instrument operating on La Palma and X-ray images of the corona from Yohkoh. These measurements are consistent with the emergence of a nearly closed magnetic structure from the solar interior into the corona. The highly non-potential field topology inferred from the data suggests that strong field-aligned currents exist in the emergent magnetic structure as it buoyantly rises through the photosphere. Material trapped in this closed structure is pulled upward to later condense into a prominence. By analogy of this small active region evolution with the observed properties of large quiescent prominences, we speculate that this process might also be operative on a much larger scale. A 3-dimensional magnetostatic model is presented which has many topological features in common with the observations.     

新浮磁流与增亮事件

本文利用阳光卫星的软Ｘ 射线资料,日本国立天文台的Ｈα单色像和相对应的北京天文台怀柔站的活动区矢量磁场资料及美国基特峰天文台的全日面磁图,对发生在１９９４ 年５ 月１８ 日的软Ｘ 射线和Ｈα增亮事件进行了仔细的研究。研究表明增亮事件明显与新浮剪切磁流出现相关,Ｈα和软Ｘ 射线亮点的投影位置正好位于新浮小磁流环的三个足点之间,同时亮点也位于分界面与光球面的交线附近,故该增亮事件也许是太阳低层大气磁重联的观测证据