On the refraction coefficient of microwaves

New formulae are developed for the evaluation of the refraction coefficient of microwaves, which is the key factor for the curvature correction of microwave EDM. These new formulae are based on two distinct humidity distributions which often characterize the atmosphere during daytime. The first case assumes that the relative humidity is constant with height. For this distribution the new formulae are based on a revised form of the Robitzsch formula which enables also the evaluation of the microwave refraction coefficient from a known refraction coefficient of light. The second case assumes that the specific humidity is constant with height.     

The Solar Irradiance Spectrum at Solar Activity Minimum Between Solar Cycles 23 and 24

On 7 February 2008, the SOLAR payload was placed onboard the International Space Station. It is composed of three instruments, two spectrometers and a radiometer. The two spectrometers allow us to cover the 16?–?2900 nm spectral range. In this article, we first briefly present the instrumentation, its calibration and its performance in orbit. Second, the solar spectrum measured during the transition between Solar Cycles 23 to 24 at the time of the minimum is shown and compared with other data sets. Its accuracy is estimated as a function of wavelength and the solar atmosphere brightness-temperature is calculated and compared with those derived from two theoretical models.     

An interpretation of the structures of α- and β-quartz based on coulomb repulsion forces

A procedure is described which allows optimisation of the positional parameters of like ions (cations or anions, respectively) under the influence of repulsive Coulomb forces. The structure is regarded as being composed of subsets for which the Coulomb energy is particularly low. Each assignment of ions to subsets allows derivation of a model with individual symmetry and parameters. Because the structure is only partly ionic and other forces than Coulomb repulsion are ignored, the positional parameters are different from the actual values of the structure. Despite the simplified treatment, there are discussions of the relative lengths of SiO bonds, the cation ordering in the quartz-like structure AlPO₄, the pressure dependence of α-quartz and the symmetry of the quartz variants. For oxygen in quartz, 3 models are obtained with the symmetry of α-quartz and one with the symmetry of β-quartz. For Si, only one model is obtained which has more similarity with α- than with β-quartz. The α-β transformation is attributed to the various kinds of optimisation of Coulomb energy of oxygen.     

Source model of the 11th July 2004 Zhongba earthquake revealed from the joint inversion of InSAR and seismological data

We use interferometric synthetic aperture radar (InSAR) and broadband seismic waveform data to estimate a source model of the 11th July, 2004 M W 6.2 Zhongba earthquake, Tibet of China. This event occurred within the seismically active zone of southwestern Tibetan Plateau where the east-west extension of the upper crust is observed. Because of limitations in one pair of InSAR data available, there are trade-offs among centroid depth, rupture area and amount of slip. Available seismic data tightly constrain ...     

The effects of atmospheric turbulence on telescopic observations

Telescopic observations to terrestrial and extraterrestrial objects are affected by atmospheric turbulence. The structure of atmospheric turbulence is reviewed in tems of the refractive index structure parameter. The mean and fluctuating refraction effects of the turbulent atmosphere on the propagation of electromagnetic waves are addressed. The known formulae for the variance and the spectrum of the angle-of-arrival fluctuations are presented and experimental results are summarised. The angular resolution is compared with the pointing precision of a telescope for visual observations through a turbulent atmosphere. The ultimate precision of direction measurements is shown to be a function of instrumental design parameters, the strength of atmospheric turbulence, and the length of the averaging period.     

西秦岭凤太矿集区丝毛岭金矿床地质地球化学特征

西秦岭凤太矿集区丝毛岭金矿床位于八卦庙造山型金矿床西侧5km左右,是一个新探明的剪切带型金矿。其成矿作用过程可分为早期石英-绢云母-硫化物阶段、中期多金属-硫化物阶段和晚期碳酸盐阶段。对早、中期的石英流体包裹体测试结果表明,丝毛岭金矿床成矿流体以富CO2、中温、低盐度为特征,总体上属于中温低盐度CO2-H2O体系,流体包裹体类型的多样性是流体不混溶性的产物。从早阶段到主成矿阶段成矿流体的温度、压力和盐度均有降低,硫逸度增高,有利于金的沉淀富集。H、O、S、C同位素研究结果,以及与八卦庙金矿床的对比分析表明,二者的成矿流体具有相似性和同源性,都是以深部来源为主的多源流体。由于丝毛岭金矿床产出的层位高于八卦庙金矿床,其成矿环境相对开放。