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101.
102.
通过对塔里木盆地陆相烃源岩所作的详细有机岩石学研究,提出了适合该盆地的陆相烃源岩有机组分分类方案,并系统地阐述各有机组分的光性、成因及岩石学特性。 相似文献
103.
104.
作者对激光热透镜光谱法测定微量钼进行了研究.试验表明,在丙酮介质中,Mo6+能被还原成Mo5+并形成钼蓝同多酸,最大吸收彼长在670um处,利用He-Ne激光器输出的632.8um的激光作光源,进行微量钼的热透镜法分析测定.两酮的存在能增强热透镜信号强度。钼含量在0.01—2.0μg/mL范围内与激光热透镜信号强度呈良好的线性关系,方法检出限为0.005μg/mL钼,已用于地质样品中微量钼的高灵敏度测定.结果满意. 相似文献
105.
The terrestrial noise in the differencial data of geomagnetic total field recorded at 21h in North China was fitted by using
the geomagnetic vector data from Beijing Observatory. The terrestrial noise level and its spatial feature in this region was
discussed. A method, which may be useful for justifying the quality of fitting, was provided in this paper. The analysis indicates
that the terrestrial noise is one of the important noise in tectonomagnetic study. It is shown that the susceptibility effect
is quite small and the orientation effect is the main component in the terrestrial noise in North China. The rough spatial
feature of the magnetic anomaly in crustal substance was infered from the spatial feature of terrestrial noise. The measurement
precision and the source noise level of data at 21h in this region were obtained in the analysis of residual noise.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 441–447, 1993. 相似文献
106.
A new technique actively controls thermal radiation and monitors sample properties during laser-heating in a diamond anvil cell. The technique can be described as a qualitative application of thermal analysis. Discontinuities in temperature, laser power, visible thermal radiation, or in their derivatives as functions of time can be associated with the enthalpy of phase transitions (such as melting) or with changes in maternal properties (such as emissivity).The technique is illustrated with melting experiments on iron-magnesium-silicate perovskite. Temperature corrections associated with these experiments are discussed and the results are briefly reviewed. 相似文献
107.
农田生态系统温室气体排放研究进展 总被引:39,自引:0,他引:39
自1985年起,中国科学院大气物理研究所利用自行设计制造的自动观测仪器系统,历时十六年先后对我国四大类主要水稻产区的甲烷排放规律及其与土壤、气象条件和农业管理措施的关系进行了系统野外观测实验,并对稻田甲烷产生、转化和输送机理进行了理论研究,探讨了控制稻田甲烷排放的实用措施,建立了估算和预测稻田甲烷排放的数值模型.在甲烷排放的时空变化规律和转化率研究方面有一系列新的发现,在稻田甲烷产生率、排放率及其与环境条件的关系方面取得一系列新的成果,以充分证据改变了国际上关于全球和中国稻田甲烷排放总量的估算.在对稻田甲 相似文献
108.
激光显微探针~(40)Ar/~(39)Ar同位素定年 总被引:10,自引:0,他引:10
已有 5 0年历史的K Ar定年法 ,由于过剩Ar和Ar丢失的普遍发现 ,使其最广泛的应用面临着严重挑战。40 Ar/ 3 9Ar分步加热释氩法是常规K Ar定年法的发展 ,它克服了常规K Ar定年法的一些局限 ,又可以测定岩浆构造热事件。激光显微探针40 Ar/ 3 9Ar定年法是在 2 0世纪末把聚焦激光束应用在40 Ar/ 3 9Ar分步加热释氩法中而发展起来的一种定年方法。它既具有常规K Ar定年法和40Ar/ 3 9Ar分步加热释氩法的所有优越性 ,又把定年引入微观领域。特别是在 2 0世纪的最后几年 ,以激光显微探针40 Ar/ 3 9Ar定年方法的完善和精度的提高为标志 ,把K Ar年代学研究推向了一个新的里程碑。微区微量高精度高分辨定年 ,把定年时限扩展到人类历史范畴 ,精细的分析技术拓宽了年代学的应用范围 ,使之解决的地质问题更广泛和深入 ,并且开始冲击着地球科学中的某些热点和难点课题。 相似文献
109.
110.
Junko KominamiShigeru Ida 《Icarus》2002,157(1):43-56
We have performed N-body simulation on final accretion stage of terrestrial planets, including the effect of damping of eccentricity and inclination caused by tidal interaction with a remnant gas disk. As a result of runway and oligarchic accretion, about 20 Mars-sized protoplanets would be formed in nearly circular orbits with orbital separation of several to ten Hill radius. The orbits of the protoplanets would be eventually destabilized by long-term mutual gravity and/or secular resonance of giant gaseous planets. The protoplanets would coalesce with each other to form terrestrial planets through the orbital crossing. Previous N-body simulations, however, showed that the final eccentricities of planets are around 0.1, which are about 10 times higher than the present eccentricities of Earth and Venus. The obtained high eccentricities are the remnant of orbital crossing. We included the effect of eccentricity damping caused by gravitational interaction with disk gas as a drag force (“gravitational drag”) and carried out N-body simulation of accretion of protoplanets. We start with 15 protoplanets with 0.2M⊕ and integrate the orbits for 107 years, which is consistent with the observationally inferred disk lifetime (in some runs, we start with 30 protoplanets with 0.1M⊕). In most runs, the damping time scale, which is equivalent to the strength of the drag force, is kept constant throughout each run in order to clarify the effects of the damping. We found that the planets' final mass, spatial distribution, and eccentricities depend on the damping time scale. If the damping time scale for a 0.2M⊕ mass planet at 1 AU is longer than 108 years, planets grow to Earth's size, but the final eccentricities are too high as in gas-free cases. If it is shorter than 106 years, the eccentricities of the protoplanets cannot be pumped up, resulting in not enough orbital crossing to make Earth-sized planets. Small planets with low eccentricities are formed with small orbital separation. On the other hand, if it is between 106 and 108 years, which may correspond to a mostly depleted disk (0.01-0.1% of surface density of the minimum mass model), some protoplanets can grow to about the size of Earth and Venus, and the eccentricities of such surviving planets can be diminished within the disk lifetime. Furthermore, in innermost and outermost regions in the same system, we often find planets with smaller size and larger eccentricities too, which could be analogous to Mars and Mercury. This is partly because the gravitational drag is less effective for smaller mass planets, and partly due to the “edge effect,” which means the innermost and outermost planets tend to remain without collision. We also carried out several runs with time-dependent drag force according to depletion of a gas disk. In these runs, we used exponential decay model with e-folding time of 3×106 years. The orbits of protoplanets are stablized by the eccentricity damping in the early time. When disk surface density decays to ?1% of the minimum mass disk model, the damping force is no longer strong enough to inhibit the increase of the eccentricity by distant perturbations among protoplanets so that the orbital crossing starts. In this disk decay model, a gas disk with 10−4-10−3 times the minimum mass model still remains after the orbital crossing and accretional events, which is enough to damp the eccentricities of the Earth-sized planets to the order of 0.01. Using these results, we discuss a possible scenario for the last stage of terrestrial planet formation. 相似文献