利用CDMA 1X+VPN技术实现十三陵地震前兆观测系统信息集成     

泽仁志玛  李志雄  周克昌  杨颖  吴利军 《地震》2009,29(3):86-92

依托“中国地震数据观测网络”项目,中国地震局地震预测研究所建立了以十三陵地震中心台为前兆台网部,8个无人值守的前兆台站为一体的前兆观测系统。 这套系统利用中国联通的CDMA 1X网络将台站接入到Internet网络,并利用VPN(Virtual Private Network)技术在Internet网络上开辟一条安全、 稳定传输隧道,实现了前兆台站、 观测设备与十三陵前兆台网部的信息集成。 文中以十三陵地震前兆观测系统为例,主要介绍了如何利用CDMA 1X 无线网络和VPN(Virtual Private Network)技术实现前兆观测系统信息集成。 十三陵地震前兆观测系统的正常运行证明,利用CDMA 1X +VPN技术的前兆观测系统组网模式可以做到投资少、 见效快、传输可靠等优势,值得推广应用。  相似文献   

Cloud Point Extraction for the Preconcentration of Silver and Palladium in Real Samples and Determination by Atomic Absorption Spectrometry     

Hossein Tavallali  Saeed Yazdandoust  Mozhdeh Yazdandoust 《洁净——土壤、空气、水》2010,38(3):242-247

A cloud point extraction procedure is presented for the preconcentration and simultaneous determination of Ag⁺ and Pd²⁺ in various samples. After complexation with 2‐((2‐((1H‐benzo[d]imidazole‐2‐yl)methoxy)phenoxy)methyl)‐1H‐benzo[d]imidazol (BIMPI), which was used as a new chelating agent, analyte ions were quantitatively extracted to a phase rich in Triton X‐114 following centrifugation, and determination was carried out by flame atomic absorption spectrometry (FAAS). Under the optimum experimental conditions (i. e., pH = 7.0, 15.0·10^–5 mol/L BIMPI and 0.036% (w/v) Triton X‐114), calibration graphs were linear in the range of 28.0–430.0 μg/L and 57.0–720.0 μg/L with detection limits of 10.0 and 25.0 μg/L for Ag⁺ and Pd²⁺, respectively. The enrichment factors were 35.0 and 28.0 for Ag⁺ and Pd²⁺, respectively. The method has been successfully applied to evaluate these metals in some real samples, including waste water, soil and hydrogenation catalyst samples.  相似文献   

X‐ray tomography of tsunami deposits: Towards a new depositional model of tsunami deposits          下载免费PDF全文

Simon Falvard  Raphaël Paris 《Sedimentology》2017,64(2):453-477

X‐ray computed microtomography is used to obtain high resolution imagery of a historical tsunami deposit in Andalusia, Spain (1755 Lisbon tsunami). The technique allows characterization of grain‐size distribution, structures, component analysis and sedimentary fabric of fine‐grained unconsolidated tsunami deposits at resolutions down to particle scale. The results are validated by comparing to data obtained using other techniques such as laser diffraction, anisotropy of magnetic susceptibility and X‐ray microfluorescence on the same deposits. Specific technical details such as sampling, scanning and image processing methods, and further improvements are addressed. The use of X‐ray computed microtomography provides new insights into the stratigraphy of the deposits and gives access to significantly more detailed view of key sedimentary features such as mudlines, rip‐up clasts, crude laminations, convolutions, floating outsized clasts and contacts between successive units. This analysis of the 1755 tsunami deposits using X‐ray computed microtomography allows the proposal of new hypotheses for the sedimentary processes forming tsunami deposits. Deposition by settling is limited and the section analysed here is dominated by a high shear stress leading to the development of traction carpets, with laminated mudlines corresponding to the basal frictional region of these carpets. The onset of the tsunami backwash is marked by a micro‐vortex resembling Kelvin–Helmoltz instabilities.  相似文献   

X‐ray spectra and polarization from accreting black holes: polarization from an orbiting spot     

M. Dov iak  V. Karas  G. Matt 《Astronomische Nachrichten》2006,327(10):993-996

The polarization from a spot orbiting around Schwarzschild and extreme Kerr black holes is studied. We assume different models of local polarization. Firstly, as a toy model we set the local polarization vector either normal to the disc plane, or perpendicular to the toroidal magnetic field. Then we examine the more realistic situation with a spot arising due to the emission from the primary source above the disc. We employ either Rayleigh single scattering or Compton multiple scattering approximations. The time dependence of the degree and angle of polarization during the spot revolution is examined as a function of the observer's inclination angle and black hole angular momentum. The gravitational and Doppler shifts, lensing effect as well as time delays are taken into account. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Fourier‐resolved spectroscopy of AGN using XMM‐Newton data     

I. E. Papadakis  Z. Ioannou  D. Kazanas 《Astronomische Nachrichten》2006,327(10):1047-1054

We present a brief account of the theory on which the novel method of ‘Fourier‐resolved spectroscopy’ is based. We summarize the results from the past application of this method to the study of Galactic Black Hole candidate sources and MCG‐6‐30‐15, and we present new results from the Fourier‐resolved spectroscopy of archival XMM‐Newton data of five AGN, namely, Mrk 766, NGC 3516, NGC 3783, NGC 4051 and Ark 564. When we combine all the past and present results from Galactic sources and AGN, we find that the slope of the Fourier‐resolved spectra in accreting black hole systems decreases with increasing frequency as ∝ f ^–0.25, irrespective of whether the system is in its High or Low state. We find significant evidence that the iron line in Mrk 766, NGC 3783 and NGC 4051 is variable on time scales ∼1 day – 1 hour. There is an indication that, just like in Galactic sources, the equivalent width of the line in the Fourier‐resolved spectra of AGN decreases with increasing frequency. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Discovery of a double peaked Fe emission line in the Cloverleaf quasar H1413+117     

G. Chartas  M. Eracleous  X. Dai  E. Agol  S. C. Gallagher 《Astronomische Nachrichten》2006,327(10):1063-1066

Our spatial and spectral analysis of a recent deep Chandra observation of H1413+117 confirms a microlensing event in a previous Chandra observation of this object performed about 5 years earlier. We present constraints on the structure of H1413+117 based on the time‐scale of this microlensing event. The analysis of the combined spectrum of the images indicates the presence of two emission line peaks at rest‐frame energies of 5.35 keV and 6.32 keV and detected at the ≳97% and ≳99% confidence levels, respectively. The double peaked Fe emission is fit well with an accretion disk‐line model, however, the best‐fit accretion disk model parameters are neither well constrained nor unique. Another possible interpretation of the Fe emission is fluorescent Fe emission from the back‐side of the wind. Additional observations are required to constrain better the model parameters. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Amplification and variability of the AGN X‐ray emission due to microlensing     

L. . Popovi&#x;  P. Jovanovi&#x;  T. Petrovi&#x;  V. N. Shalyapin 《Astronomische Nachrichten》2006,327(10):981-984

We consider the contribution of microlensing to the AGN Fe Kα line and X‐ray continuum amplification and variation. To investigate the variability of the line and X‐ray continuum, we studied the effects of microlensing on quasar X‐ray spectra produced by crossing of a microlensing pattern across a standard relativistic accretion disk. To describe the disk emission we used a ray tracing method considering both metrics, Schwarzschild and Kerr. We found that the Fe Kα and continuum may experience significant amplification by a microlensing event (even for microlenses of very small mass). Also, we investigate a contribution of microlensing to the X‐ray variability of high‐redshifted QSOs, finding that cosmologically distributed deflector may contribute significantly to the X‐ray variability of high‐redshifted QSOs (z > 2). (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Light bending models in AGNs     

G. Miniutti 《Astronomische Nachrichten》2006,327(10):969-976

We review the MCG–6‐30‐15 observations and results that provided the motivation for the light bending model. We present a summary of the main properties of the model and discuss its application to MCG–6‐30‐15 briefly mentioning other X‐ray sources showing the same qualitative behaviour. Finally, we report on one of the most spectacular cases so far of short‐timescale variability of a redshifted Fe K line in the Seyfert galaxy NGC 3516, most likely due to an orbiting spot or flare in the relativistic region of the accretion disc. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

The broad iron line physics: summary and outlook     

Y. Tanaka 《Astronomische Nachrichten》2006,327(10):1098-1100

A brief overview of the ESAC/XMM‐Newton Science Operations Centre Workshop on “Variable and Broad Iron Lines around Black Holes” is presented. Following the relativistic disk‐line theory of accreting black holes, ASCA discovered such broad iron lines from several AGN. XMM‐Newton and Chandra confirmed the ASCA results, but also found more complexities. It was pointed out that poor modelling of the continuum may mimic broad iron line, if ionized absorbers are present. This degeneracy between the broad line and the continuum shape was shown to be resolved by separately determining the continuum and the reflection component with use of an accurate hard X‐ray spectrum obtained with Suzaku. As a result, the relativistic broad iron lines are now robust. Time variations of the primary continuum and the reflection component are often decoupled, the latter varying little. This is explained by the light bending model that applies in the region near to an extreme Kerr hole. The red‐ and/or blueshifted transient iron line features were found with XMM‐Newton, some of which revealed a possible quasi‐periodicity. Such transient features are important dynamical probes of the black hole vicinity. The remaining issues are briefly mentioned. Finally, there is no doubt that the broad line physics continues to be extremely important. Prospects for the future development are discussed, which justify large next‐generation missions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

吸积盘和冕的研究与应用     

《天文研究与技术》2001,(1)

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