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991.
本文研究了用ODS柱对DDTC与Cu、Co、Ni、Hg四种重金属离子螯合物的分离测定方法。经过对流动相及其配比、波长、柱温、压力、流速等色谱条件进行的选择,对共存离子影响的分析,确定了最佳分离分析条件。以58:42(v:y)的乙醇水溶液作流动相在R.P.柱上分离,于254nm处检测。在0.0064~1.Oμg/ml(Cu),0.0064~1.0μg/ml(Co),0.0032~1.0μg/ml(Ni),0.010~1.0μg/ml(Hg)浓度范围内,线性关系良好。对含量在线性范围内的天然水样和人尿样进行了分析测定,回收率在97.0~109.0%之间,变异系数不超过5.6%,结果较好。 相似文献
992.
本文讨论了太阳黑子活动,地球自转运动。大气降水和气压等环境因子与帕米尔及其邻近地区(新疆部分)大震活动的关系,进行了相关统计分析,在α=0.05置信水平的统计检验是显著的。认为,环境因子与大震活动存在着较好的相关关系,地震的孕育不仅是由于地壳内部应力的积累和调整,而且还有地球外部的地震环境因子的调制和触发作用。 相似文献
993.
994.
冀东高级变质岩石的流体包裹体研究 总被引:5,自引:5,他引:5
冀东高级变质的石榴石斜长片麻岩、含或不含石榴石的角闪二辉斜长片麻岩、紫苏花岗岩、斜长角门岩等岩石中的流体包裹体主要有4类,按形成的先后顺序依次为:(1)H2O和CO2两液相包裹体,CO2的部分均一温度是-12℃,密度1.04g/cm3,H2O含量21%~39%(mole%),CO2含量50%~71%(mole%);(2)CO2液相包裹体,冰点温度-56℃~-61℃,均一温度-7.4℃~-35.1℃,CO2密度约为1.05g/cm3,CO2含量82.1%~98.4%(mole%),还有少量的CH4、N2和H2等组分;(3)H2O和CO2多相包裹体,CO2的部分均一温度7℃~28℃,CO2密度为0.64~0.93g/cm3,气相组分以CO2、CH4和CO为主,液相成分主要是H2O和CO2;(4)多世代盐水溶液包裹体,冰点温度-0.5℃~-20℃,盐度0.87%~22.8%(wt%),盐水密度0.7~1.05g/cm3,均一温度在150℃~200℃和约300℃,存在两个峰值。不同世代的流体包裹体记录了等密度降温的P-T路径。包裹体反映的变质作用早期降温过程流体的H2O/H2O+CO2(mole)比值降低,晚期升高 相似文献
995.
Interpretation of Holocene lake-level change from diatom assemblages in Lake Sidi Ali,Middle Atlas,Morocco 总被引:1,自引:0,他引:1
P. A. Barker N. Roberts H. F. Lamb S. van der Kaars A. Benkaddour 《Journal of Paleolimnology》1994,12(3):223-234
While palaeohydrological changes in non-outlet lakes provide a key proxy indicator of past climatic fluctuations, for lake systems which have been chemically insensitive, it is necessary to use indicators of water depth rather than salinity to reconstruct their hydro- climatic histories. A study of diatoms in the modern sediments of Sidi Ali, a non-outlet lake in the Middle Atlas of Morocco, has shown a statistically significant correlation between water depth and the ratio of planktonic to littoral diatoms. This relationship is used to calibrate fossil diatom assemblages from a lake sediment core from the same lake to provide a quantitative index of water levels over the pastc. 6500 years. Palaeoecological evidence suggests that climatically induced hydrological variations have dominated the bulk of the mid-late Holocene lake sediment record, with significant human-induced catchment disturbance only occurring during the twentieth century. The pattern of water depth fluctuations suggests that the response time of the regional groundwater system to climatic forcing is <100 years.This is the third in a series of papers published in this issue on the paleolimnology of arid regions. These papers were presented at the Sixth International Palaeolimnology Symposium held 19–21 April, 1993 at the Australian National University, Canberra, Australia. Dr A. R. Chivas served as guest editor for these papers. 相似文献
996.
997.
998.
关于我国高技术开发区建设与布局的几个问题 总被引:5,自引:0,他引:5
本文简要阐述了高技术对推动国民经济发展的重要作用,指出了我国建立高技术开发区的必要性,可能性及其战略思想,并提出了分三个层次布局的建设方案。 相似文献
999.
Anne M. Hofmeister 《Physics and Chemistry of Minerals》2006,33(1):45-62
Thermal diffusivity (D) of garnets with diverse chemical compositions was measured using the laser-flash technique, which is accurate (±2%) and
isolates the lattice component from direct radiative transfer. Temperatures ranged from ~290 to ~1,600 K (unless limited by
melting). Seven synthetic (e.g., YAG, GGG) and 15 natural garnets with two types of ionic substitution [Ca3(Fe,Al)2Si3O12 and (Mg,Fe,Ca)3Al2Si3O12] and varying amounts of OH- were examined. Cation substitution or hydroxyl incorporation lowers D from end-member values. Thermal diffusivity is constant once the temperature (T) exceeds a critical value (T
sat) of ~1,100 to 1,500 K. From ~290 K to T
sat, the measurements are best represented by 1/D=A+BT+CT
2 where A, B, and C are constants. These constants vary little among diverse chemical compositions, suggesting that the oxygen
sublattice controls heat transport. Higher order terms are needed only when T
sat is low, such as Ant Hill garnet wherein 1/D=0.049403+0.0032299T−2.3992T
2×10−6+6.0168T
3×10−10(1/D in s/mm2; T in K). The mean free path (λ, computed from D and sound velocities) is slightly larger than the lattice parameter above T
sat, in accord with phonon–phonon interactions requiring non-localized modes. At most temperatures, λ is nm-sized. Large values
of λ are obtained by extrapolation to a few Kelvins, suggesting that boundary scattering can only be important at extremely
cold temperatures. The observed behavior with T and chemical composition is consistent with the damped harmonic oscillator model. Phonon transport is best represented by
inverse thermal diffusivity wherein 1/D goes as T
n where n is between 1 and 3 up to ~200 K, depends on a quadratic or cubic polynomial at moderate T, but is constant above T
sat. The predicted and observed temperature response of 1/D mimics the well-known form for heat capacity, in that acoustic modes control heat transport near cryogenic temperatures,
optic phonons dominate above ambient temperature, and a limit analogous to that of Dulong and Petit is reached at very high
temperature, due to full population of discrete phonon states. 相似文献
1000.
Seismic imaging of the transitional crust across the northeastern margin of the South China Sea 总被引:23,自引:0,他引:23
Crustal structure across the passive continental margin of the northeastern South China Sea (SCS) is presented based on a deep seismic survey cooperated between Taiwan and China in August 2001. Reflection data collected from a 48-hydrophone streamer and the vertical component of refraction/reflection data recorded at 11 ocean-bottom seismometers along a NW–SE profile are integrated to image the upper (1.6–2.4 km/s), lower (2.5–2.9 km/s), and compacted (3–4.5 km/s) sediment, the upper (4.5–5.5 km/s), middle (5.5–6.5 km/s) and lower (6.5–7.5 km/s) crystalline crust successively. The velocity model shows that the thickness (0.5–3 km) and the basement of the compacted sediment are strongly varied due to intrusion of the magma and igneous rocks after seafloor spreading of the SCS. Furthermore, several volcanoes and igneous rocks in the upper/middle crust (7–10 km thick) and a high velocity layer (0–5 km thick) in the lower crust of the model are identified as the ocean–continent transition (OCT) below the lower slope in the northeastern margin of the SCS. A thin continent NW of the OCT and a thick oceanic crust SE of the OCT in the continental margin of the northeastern SCS are also imaged, but these transitional crusts cannot be classified as the OCT due to their crustal thickness and the limited amount of the volcano, the magma and the high velocity layer. The extended continent, next to the gravity low and a sag zone extended from the SW Taiwan Basin, may have resulted from subduction of the Eurasian Plate beneath the Manila Trench whereas the thick oceanic crust may have been due to the excess volcanism and the late magmatic underplating in the oceanic crust after seafloor spreading of the SCS. 相似文献