Mitigation of time-series InSAR turbulent atmospheric phase noise: A review

Synthetic Aperture Radar(SAR)interferometry is one of the most powerful remote sensing tools for ground deformation detection.However,tropospheric delay greatly limits the measurement accuracy of the InSAR technique.While vertically stratified tropospheric delays have been extensively investigated and well tackled,turbulent tropospheric phase noise still remains an intractable issue.In recent years,great efforts have been made to reduce the influence of turbulent atmospheric delay.This contribution is intended to provide a systematic review of the progress achieved in this field.First,it introduces the physical characteristics of atmospheric signals in interferograms.Then,a review of the main mitigation algorithms proposed in the literature is provided.In addition,the strengths and weaknesses of each approach are analyzed to provide guidance for choosing a suitable method accordingly.Finally,sug-gestions for resolving the challenging issues and an outlook for future research are given.

AN ISOBAR-ISOTHERMAL PHASE DIAGRAM OF THE Nd-Fe-B SYSTEM AT ATMOSPHERIC PRESSURE AND 1000℃

An isothermal section of Nd-Fe-B system at 1000℃ and the phase equilibrium relationship in Fe-Nd and Nd-B binary systems were investigated with diffusion couple by means of metallographic observation, electron microprobe analysis and X-ray diffraction.It was shown that there are three stable ternary com- pounds,Nd_2Fe_(14)B,Nd_2Fe_7B_6 and Nd_9Fe_3B_8 in Nd-Fe-B system at 1000℃.None of these phases has solu- bility,that is,they are exactly stoichiometric phases.On the other hand,there exist rather wide two-phase regions between Nd_2Fe_7B_6 and liquid as well as between Nd_9Fe_3B_8 and liquid.It was identified that there is no NdFe_2 compound in the system under atmospheric pressure.

Lunar Phases and Atmospheric Electric Field

The association between the lunar phases and the atmospheric electric field has been investigated from the superposed epoch analysis of the long series of continuous data of the vertical electric field for Colaba, Bombay (18 ° 53'N, 73 ° 48'E 11 mASL) for the period 1947-1966. Also the periodicities in the atmospheric electric field have been studied from the spectral analysis of the data. The study has indicated that when the full moon is within 4 of the ecliptic plane i.e.,Bf 4 ° , the electric field peaks on the day of the full moon followed by a steep fall in the field values up to 4 days following the full moon day and there after it showed a steep increase. Also, the electric field has exhibited 5-9 day periodicity and its multiples are nearly always present. The periodicity in the electric field corresponds with the average time interval between the successive magnetic sector boundary (MSB ) crossings i.e., 7 days. On most of the occasions, the MSB crossing day is associated with a maximum of one or more of the wavelengths derived from the spectral analysis of the atmospheric electric field.

Present-day deformation of Agung volcano,Indonesia, as determined using SBAS-InSAR

Based on ALOS PALSAR images, time series deformation fields of the Agung w^lcann area were obtained using SBAS-InSAR in 2007 -2009. The time series deformation showed obvious inflation around the Agung volcano area, which was positively correlated with time. We modeled the cumulated deformation interferogram based on Mogi point source and vertical prolate spheroid source. The deformation model indicated that the vertical prolate spheroid model fit the observed deformation reasonably well. The magma chamber was loc, ated beneath the eenter of the volcano at a depth of approximately 5 km beneath the summit.

Kinetic Study on Uniformity of AlGaAs Grown by MOVPE

The growth kinetic factors affecting the uniformity of AlGaAs in a horizontal atmospheric MOVPE (AP-MOVPE) reactor with a horizontal susceptor were investigated. The decrease in the growth rate of AlGaAs (R-AlGaAs) in the now direction is related to both the gas depletion and the decreasing growth rate of GaAs (R-GaAs) with the increasing gas temperature in this direction. The change of x in the flow direction has relations not only to the different changes of R-GaAs and R-AlAs(the growth rate of AlAs) with the gas temperature, according to which x will increase in the now direction, but also to the higher depletion rate of Al containing species compared with that of Ga containing species, according to which x: will decrease. Due to the similar reason, the loss of symmetry about the length axis of the susceptor can also result in the monotone increase or decrease in thickness and x in the crosswise direction.

Yttria-stabilized-zirconia hollow spheres prepared by atmospheric plasma spray

Yttria-stabilized-zirconia （YSZ） hollow spheres are widely utilized for their novel physical and chemical properties. However, developing a simple and low-cost method for preparing such hollow spheres still remains a great challenge. In this paper, an atmospheric plasma spray （APS） method is introduced, and the formation mechanism of hollow 7YSZ （ZrO2-7wt%Y2O3） spheres is presented. The hollow sphere morphology was observed by scanning electron microscopy （SEM） when agglomerated and sintered 7YSZ powders were used. Additionally, additive composition changes, phase transformations, and the thermal behavior of 7YSZ powders were analyzed by energy dispersive spectroscopy （EDS）, X-ray diffractometry （XRD）, thermogravimetric analysis （TG） and differential scanning calorimeter analysis （DSC）. Furthermore, the phase transformations of agglomerated and sintered 7YSZ powders, 7YSZ hollow spheres that annealed at various temperatures for different times are analyzed.