燃料矿产资源发展趋势分析

大量可利用的非再生性能源限于重氢和地下热干源.大量的可再生性能源是太阳和大气层中的电.这四种可作为基本的能源,但是至少在今后的几十年中它们对总的能源预算未必能作出重要贡献.合成燃料已投入生产,然而由于经济的和环境上的考虑,能源形式的普遍转换受到限制.风、水和生物质的转变将得到发展,但其作用仍比较小.因此,可以直接预见的能源需求的大部分还是要靠煤、铀和石油来提供.煤的利用可以回溯到几千年前的青铜器时代,那时用煤做火葬的燃料.煤被古希腊和罗马人利用,以后为美洲印第安人、中国人秆欧洲国家所利用,并逐渐取代了动物、风、水和     

Explosion of comet Shoemaker-Levy 9 on entry into the Jovian atmosphere

We use the astrophysical hydrocode ZEUS to compute high-resolution models of the disruption and deceleration of cometary fragments striking Jupiter. We find that simple analytic and semianalytic models work well for kilometer-size impactors. We show that previous numerical models that placed the explosion much deeper in the atmosphere failed to fully resolve important gasdynamical instabilities. These instabilities tear the comet apart, greatly increase its effective cross section, and bring it to an abrupt halt. A 1 km diameter fragment loses over 90% of its kinetic energy within a single scale height at an atmospheric pressure of order 10 bars. For all practical purposes, it explodes.     

人工源超低频电磁波技术及在首都圈地区的测量研究

超低频 (SLF)电磁波技术利用地球物理和无线电物理相结合的原理 ,由人工产生大功率电磁波信号。在地面很大范围的许多测点同时测量该信号 ,可研究空间电磁场和地下电阻率结构 ,研究地震等引起的电磁场异常变化 ,探测地壳结构和地下资源。在首都圈地区的观测表明 ,SLF信号的功率谱密度超过天然场源信号数倍以上 ,所得到的视电阻率数据精度远高于天然源方法 ,并有长时间的稳定性。在测量期间距测点约 12 0km发生的迁安 4 .2级地震与观测的电磁场异常和视电阻率的变化有较好的对应性 ,并对产生这些变化的可能的成因机制进行了探讨 ,推测它们是区域应力场和震源区局部构造综合作用的结果。     

孔隙水压力对岩石裂纹扩展影响的数值模拟

应用岩石破坏过程渗流-应力-损伤(FSD)耦合分析软件F-RFPA2D,通过对孔隙水压作用下岩石试件加载破坏过程的数值模拟,对孔隙水压力大小和梯度对岩石试样中裂纹的萌生和扩展进行了数值模拟研究。模拟结果再现了孔隙水压力作用下裂纹萌生扩展的全过程,表明孔隙水压力大小和梯度对岩石中裂纹的萌生和扩展模式都有很大的影响。     

大尺度电离层行扰的GPS观测

利用日本境内的高空间分辨率的双频GPS台站资料,观测研究了发生于2000年7月中旬太阳强活动期间的一次大尺度电离层行扰. 结果表明:在7月15日11:00UT-1:00UT期间观测区域的电离层中出现了大尺度电离层行扰. 在15:00UT之前,扰动周期为2h左右,在15:00UT以后,扰动周期为1h左右;总电子含量扰动幅度的变化范围约为1-2TECU;通过对15:00-17:00UT之间总电子含量扰动曲线同相位点的分析,发现这期间的电离层行扰的扰动速度约为600-700m/s,扰动波长在2200km左右,扰动传播的方向几乎沿着经线从高纬向低纬传播. 该行扰与此次强太阳活动有直接的关系,因其发生在7月15日的磁暴急始之前数小时,因此与磁暴本身没有因果关系,应与磁暴之前先期到达地球空间的高能质子流有关.     

DESIGN OF SEDIMENT FLUSHING OUTLETS

1 INTRODUCTION Considerable amount of sediment discharge enters in a canal at the head works. This sediment discharge is carried safely as the slopes of the canal in the head reaches are large. Subsequently, for economy, the slopes of canal are reduced in the downstream reaches. This makes the sediment concentration far excess of its carrying capacity. This excess sediment has to be removed by suitable design of a sedimentation basin. Also, one of the requirements for successful function…     

Study of Central Intensity Ratio of Seyfert Galaxies in Nearby Universe

We use the recently discovered simple photometric parameter Central Intensity Ratio(CIR) determined for a sample of 57 nearby(z <0.02) Seyfert galaxies to explore the central features of galaxies and their possible connection with galaxy evolution.The sample of galaxies shows strong anti-correlation between CIR and mass of their central supermassive black holes(SMBHs).The SMBH masses of ellipticals are systematically higher for a given CIR value than those for lenticulars and spirals in the s...     

X-Ray and Ultraviolet Flares on AT Microscopii Observed by AstroSat

We present observations of the active M-dwarf binary AT Mic(dM4.5e+dM4.5e) obtained with the orbital observatory Astro Sat. During 20 ks of observations, in the far-ultraviolet(130–180 nm) and soft X-ray(0.3–7 keV)spectral ranges, we detected both quiescent emission and at least five flares on different components of the binary.The X-ray flares were typically longer than and delayed(by 5–6 minutes) with respect to their ultraviolet counterparts, in agreement with the Neupert effect. Using X-ray ...