西安地区部分古遗址考古地磁研究

通过对陕西耀州窑遗址内4个古窑,临潼兵马俑一号坑,西铜一级公路经过黄堡工地开挖的两个五代窑,以及耀州窑博物馆仓库工地内开挖的一个金代窑和一个春秋窑遗址的古地磁研究,初步得出了西安地区古地磁场变化的规律,为鉴定从春秋到金代西安地区的古遗址、古文物提供了考古地磁学上的一个粗略的标准。     

A new preparation process of coal-based magnetically activated carbon

Fe/C-based magnetically activated carbon （MAC） was obtained by carbonizing and activating its precursor, that was prepared by co-precipitation of anthracite coal impregnated in ferric chloride solution. The effect of the concentrations of FeC13 and pH of solution on BET surface area, pore volume and magnetic properties of the MAC was studied by BET N2 adsorption and VSM method. The results indicated that the magnetization of MAC gradually increases with increasing concentration of FeC13 and pH value of solution, and BET surface area was inclined to fluctuation. The largest BET surface area and magnetization of MAC were 1327.5 m2/g and 35.56 emu/g, respec- tively. The form of magnetic matter in the magnetically activated carbon was mainly Fe3C by X-ray powder diffrac- tion （XRD） and magnetic attraction test.     

强质子耀斑活动区的形态和旋转特征

本文研究结果表明：同一黑子群在日面期间的顺或反时针方向的旋转运动会先后并存．质子耀斑前1～2无，黑子群的旋转角速度达到极大．耀斑后，磁绳的松弛，黑子群可能会反向旋转，强的剪切过程和质子耀斑可能会再度出现．强质子耀斑活动区的共同特征是：（1）形态为单个团状结构δ型黑子，即众多异极性本影核紧锁在同一黑子半影中；（2）黑子面积＞1000×10－6半球面积，日面跨度＞10°；（3）黑子群都有快速的旋转运动．这类活动区，如果在日面西部活动性明显地增强，那么这个活动区在未来转到日面边缘及其背后、或再次从日面东边缘转出时，定能再次爆发耀斑和伴随较强质子事件。     

单机械手夹持状态下钻杆运移平稳性分析

本文主要针对一种新型的可以保留钻杆旋转自由度的机械手,研究其运移钻杆时的稳定性和安全性是否满足要求。该机械手通过蓄能器提高了停泵保压效果,通过滚轮结构保留了钻杆的旋转自由度。本文建立了机械手的多体动力学模型及配套的液压控制回路,并进行机-液联合仿真分析。在分别改变钻杆直径和液压回路压力的条件下,观察机械手夹紧效果。通过仿真得到了钻杆的夹紧力变化曲线及钻杆重心位置变化曲线,确定了液压系统的许用压力范围,并验证了单机械手夹持状态下钻杆运移平稳性满足要求。     

Invariant rotational curves in Sitnikov's Problem

The Sitnikov's Problem is a Restricted Three-Body Problem of Celestial Mechanics depending on a parameter, the eccentricity,e. The Hamiltonian,H(z, v, t, e), does not depend ont ife=0 and we have an integrable system; ife is small the KAM Theory proves the existence of invariant rotational curves, IRC. For larger eccentricities, we show that there exist two complementary sequences of intervals of values ofe that accumulate to the maximum admissible value of the eccentricity, 1, and such that, for one of the sequences IRC around a fixed point persist. Moreover, they shrink to the planez=0 ase tends to 1.     

The Influence of Reactive Torques on Comet Nucleus Rotation

Reactive torques, due to anisotropic sublimation on a comet nucleus surface, produce slow variations of its rotation. In this paper the secular effects of this sublimation are studied. The general rotational equations of motion are averaged over unperturbed fast rotation around the mass center (Euler-Poinsot motion) and over the orbital comet motion. We discuss the parameters that define typical properties of the rotational evolution and discover different classifications of the rotational evolution. As an example we discuss some possible scenarios of rotational evolution for the nuclei of the comets Halley and Borrelly.