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781.
对同一地区但Re、Os含量不同的一组辉钼矿样品,分别采用电感耦合等离子体质谱(ICP-MS)和负离子热表面电离质谱(NTIMS)对其Re-Os年龄进行了测定比较。结果表明,该组样品的平均Re-Os模式年龄分别为(138.3±4.0)Ma和(141.0±3.6)Ma(2σ,n=9),采用ISOPLOT软件的模式1进行等时线计算,得到等时线年龄分别为(138.6±2.9)Ma(2σ,n=9)和(141.6±1.9)Ma(2σ,n=9),两者在目前水平下的误差范围内基本一致。另外,分别采用ICP-MS和NTIMS对辉钼矿Re-Os年龄国家一级标准物质GBW04435和GBW04436进行了测定,所得的结果吻合也较好。  相似文献   
782.
宝石中常见过渡金属离子致色的理论解释   总被引:5,自引:0,他引:5  
从晶体场理论或配位场理论出发,应用群论的方法,从理论上系统地解释了宝石中常见的因过渡金属离子在不同的配位场环境下而引起的能级分裂,并详细地阐述了这一理论分析的程序,最后列举实例并给予了理论解释。  相似文献   
783.
The hydroxyl in phyllosilicate minerals is the most common occurrence of water in primitive meteorites. Direct hydrogen isotopic analysis of this water component using an ion microprobe has been made in some glassy or phyllosilicate spherules from the Al Rais (CR) and Orgueil (CI) chondrites. The spherules from Al Rais show large deuterium excesses (δD = +200 -+800‰) relative to terrestrial standards, whereas deuterium-enrichments in the spherules from Orgueil are much smaller (δD = +40 - +130‰). The phyllosilicate spherules are products of  相似文献   
784.
Continuous measurements of pH precipitation falling from cumulus clouds in semi-arid region(Colorado,USA),and in wet temperate zone(Bologna,Italy)were made.In Colorado the pHwas constant at 7.3 for a period of time,and later changed to 7.0 and remained constant at thisvalue during the remainder of the storm.In Italy the pH fluctuated continuously between theapproximate values of 5.7 and 6.4 during the storm.The changes in hydrogen ion concentrationreflect the chemical composition of cloud condensation nuclei and of scavenged aerosol particles andgases presented in the region.  相似文献   
785.
地面电晕离子对空中引雷始发过程的影响   总被引:7,自引:1,他引:6  
利用已建立的“地面电晕离子的演化模式”对甘肃省平凉地区一次雷暴过程的空中电荷密度和环境电场的演化情况进行了模拟,发现地面尖端产生的电晕离子如果不被俘获便可在1min左右内到达500m的高度上。对空中引雷火箭发射前的空中电场分析表明,引雷成功的关键除有足够长的导线以使导线两端的电场产生畸变外,另一个重要的条件是火箭-导线系统顶端能处于强的环境电场中以满足顶部流光的产生和持续传输。另外,低空较强的环境电场对火箭-导线系统下端下行流光的发展和空气间隙的击穿有重要的促进作用。一次空中引雷触发高度上的电场大于50.0kV/m,火箭-导线系统下行正流光持续传输的电场值为19.0kV/m,放电过程首先起始于火箭-导线系统下端正流光的产生。根据多年的实验资料,建议实际引雷试验时,以500m高度上的电场为参考来决定火箭的发射时刻,北方雷暴大于50kV/m,南方雷暴大于25kV/m。  相似文献   
786.
Surfacemineralogyisoneofthemodernbranchesofmin-eralogy.Theresearchoftheinterfaceofmineral-liquid,namelythestudyonthereactiono...  相似文献   
787.
The first-order perturbation approximation is applied to calculate the rate coefficients of vibrational energy transfer in collisions involving vibrationally excited molecules in the absence of non-adiabatic transitions. The factors of molecular attraction, oscillator frequency change, anharmonicity, 3-dimensionality and quasiclassical motion have been taken into account in the approximation. The analytical expressions presented have been normalized on experimental data of VT-relaxation times in N2 and O2 to obtain the steric factors and the extent of repulsive exchange potentials in collisions N2–N2 and O2–O2. The approach was applied to calculate the rate coefficients of vibrational-vibrational energy transfer in the collisions N2–N2, O2–O2 and N2–O2. It is shown that there is good agreement between our calculations and experimental data for all cases of energy transfer considered.  相似文献   
788.
A statistical investigation of the location of onset of intermediate and gyrating ion populations in the Earths foreshock is presented based on Fixed Voltage Analyzer data from ISEE 1. This study reveals the existence of a spatial boundary for intermediate and gyrating ion populations that coincides with the reported ULF wave boundary. This boundary position in the Earths foreshock depends strongly upon the magnetic cone angle BX and appears well defined for relatively large cone angles, though not for small cone angles. As reported in a previous study of the ULF wave boundary, the position of the intermediate-gyrating ion boundary is not compatible with a fixed growth rate of the waves resulting from the interaction between a uniform beam and the ambient plasma. The present work examines the momentum associated with protons which travel along this boundary, and we show that the variation of the boundary position (or equivalently, the associated particle momentum) with the cone angle is related to classical acceleration mechanisms at the bow shock surface. The same functional behavior as a function of the cone angle is obtained for the momentum predicted by an acceleration model and for the particle momentum associated with the boundary. However, the model predicts systematically larger values of the momentum than the observation related values by a constant amount; we suggest that this difference may be due to some momentum exchange between the incident solar-wind population and the backstreaming particles through a wave-particle interaction resulting from a beam plasma instability.  相似文献   
789.
The vibrational distribution of nitric oxide in the polar ionosphere computed according to the one-dimensional non-steady model of chemical and vibrational kinetics of the upper atmosphere has been compared with experimental data from rocket measurement. Some input parameters of the model have been varied to obtain the least-averaged deviation of the calculated population from experimental one. It is shown that the least deviation of our calculations from experimental measurements depends sufficiently on both the surprisal parameter of the production reaction of metastable atomic nitrogen with molecular oxygen and the profile of atomic oxygen concentration. The best agreement with the MSIS-83 profile was obtained for the value of surprisal parameter corresponding to recent laboratory estimations. The measured depression of level v = 2 is obtained in the calculation that uses sufficiently increased concentrations of atomic oxygen. It is pointed out that similar measurements of infrared radiation intensities could be used to estimate the atomic oxygen concentrations during auroral disturbances of the upper atmosphere.  相似文献   
790.
The implantation of artificial quartz with nickel ion has succeeded in using a heavy ion accelerator. The quartz with nickel ion is called ”nickel quartz“. The sensitivity of their thermoluminescence (TL) response to the beta radiation was decreased with the increasing of irradiating and heating times. Two TL characteristics have appeared: the sensitivity of TL response at lower temperature (ll0°C) peaks of the nickel quartz to beta radiation is higher than that of the pure quartz, this results from the Ni+1 ion entering the quartz lattice; and a new peak appearing at 445°C may be related with both Ni+1 and Ni+3.  相似文献   
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