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421.
Rajmal Jain Vishal Joshi S. L. Kayasth Hemant Dave M. R. Deshpande 《Journal of Astrophysics and Astronomy》2006,27(2-3):175-192
We present the first results from the ‘Low Energy Detector’ pay-load of ‘Solar X-ray Spectrometer (SOXS)’ mission, which was
launched onboard GSAT-2 Indian spacecraft on 08 May 2003 by GSLV-D2 rocket to study the solar flares. The SOXS Low Energy
Detector (SLD) payload was designed, developed and fabricated by Physical Research Laboratory (PRL) in collaboration with
Space Application Centre (SAC), Ahmedabad and ISRO Satellite Centre (ISAC), Bangalore of the Indian Space Research Organization
(ISRO). The SLD payload employs the state-of-the-art solid state detectors viz., Si PIN and Cadmium-Zinc-Telluride (CZT) devices
that operate at near room temperature (-20°C). The dynamic energy range of Si PIN and CZT detectors are 4–25 keV and 4–56
keV respectively. The Si PIN provides sub-keV energy resolution while CZT reveals ∼1.7keV energy resolution throughout the
dynamic range. The high sensitivity and sub-keV energy resolution of Si PIN detector allows the measuring of the intensity,
peak energy and equivalent width of the Fe-line complex at approximately 6.7 keV as a function of time in all 8 M-class flares
studied in this investigation. The peak energy (E
p) of Fe-line feature varies between 6.4 and 6.8 keV with increase in temperature from 9 to 34 MK. We found that the equivalent
width (ω) of Fe-line feature increases exponentially with temperature up to 20 MK but later it increases very slowly up to
28 MK and then it remains uniform around 1.55 keV up to 34 MK. We compare our measurements ofw with calculations made earlier by various investigators and propose that these measurements may improve theoretical models.
We interpret the variation of both Epand ω with temperature as the changes in the ionization and recombination conditions in the plasma during the flare interval
and as a consequence the contribution from different ionic emission lines also varies. 相似文献
422.
In the present work the cosmic ray data of three different neutron monitoring stations, Deep River, Inuvik, and Tokyo, located
at different geomagnetic cutoff rigidities and altitudes have been harmonically analyzed for the period 1980–95 for a comparative
study of diurnal semi-diurnal and tri-diurnal anisotropies in cosmic ray intensity in connection with the change in interplanetary
magnetic field Bz component and solar wind velocity on 60 quietest days. It is observed that the amplitudes of all the three
harmonics increase during the period 1982–84 at all the stations during the high speed solar wind stream epoch and remain
low during the declining phase of the stream. The amplitudes of the three harmonics have no obvious characteristics associated
with the time variation of magnitude of the Bz component. The phases of all the three harmonics have no time variation characteristics
associated with solar wind velocity and Bz.
Published in Astrofizika, Vol. 49, No. 4, pp. 651–664 (August 2006). 相似文献
423.
424.
Geotechnical and Geological Engineering - The present work aims to understand the stress–strain response of an igneous rock, metadolerite, typically found in dyke form, under high loading... 相似文献
425.
Investigations related to scientific deep drilling to study reservoir-triggered earthquakes at Koyna,India 总被引:1,自引:0,他引:1
Harsh Gupta N. Purnachandra Rao Sukanta Roy Kusumita Arora V. M. Tiwari Prasanta K. Patro H. V. S. Satyanarayana D. Shashidhar K. Mallika Vyasulu V. Akkiraju Deepjyoti Goswami Digant Vyas G. Ravi K. N. S. S. S. Srinivas M. Srihari S. Mishra C. P. Dubey D. Ch. V. Raju Ujjal Borah K. Chinna Reddy Narendra Babu Sunil Rohilla Upasana Dhar Mrinal Sen Y. J. Bhaskar Rao B. K. Bansal Shailesh Nayak 《International Journal of Earth Sciences》2015,104(6):1511-1522
426.
In the Soil Conservation Service Curve Number (SCS‐CN) method, the three levels of antecedent moisture condition (AMC) permit unreasonable sudden jumps in curve numbers, which result into corresponding jumps in the estimated runoff. A few recently developed SCS‐CN‐based models obviate this problem, yet they have several limitations. In this study, such a model incorporating a continuous function for antecedent moisture has been presented. It has several advantages over the other existing SCS‐CN‐based models. Its application to a large dataset from US watersheds showed to perform better than the existing SCS‐CN method and the others based on it. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
427.
Spatio-temporal heterogeneity and changes in extreme precipitation over eastern Himalayan catchments India 总被引:1,自引:1,他引:0
Vishal?Singh Manish?Kumar?GoyalEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(10):2527-2546
This study draws attention on the extreme precipitation changes over the eastern Himalayan region of the Teesta river catchment. To explore the precipitation variability and heterogeneity, observed (1979–2005) and statistically downscaled (2006–2100) Coupled Model Intercomparison Project Phase Five earth system model global circulation model daily precipitation datasets are used. The trend analysis is performed to analyze the long-term changes in precipitation scenarios utilizing non-parametric Mann–Kendall (MK) test, Kendall Tau test, and Sen’s slope estimation. A quantile regression (QR) method has been applied to assess the lower and upper tails changes in precipitation scenarios. Precipitation extreme indices were generated to quantify the extremity of precipitation in observed and projected time domains. To portrait the spatial heterogeneity, the standard deviation and skewness are computed for precipitation extreme indices. The results show that the overall precipitation amount will be increased in the future over the Himalayan region. The monthly time series trend analysis based results reflect an interannual variability in precipitation. The QR analysis results showed significant increments in precipitation amount in the upper and lower quantiles. The extreme precipitation events are increased during October to June months; whereas, it decreases from July to September months. The representative concentration pathway (RCP) 8.5 based experiments showed extreme changes in precipitation compared to RCP2.6 and RCP4.5. The precipitation extreme indices results reveal that the intensity of precipitation events will be enhanced in future time. The spatial standard deviation and skewness based observations showed a significant variability in precipitation over the selected Himalayan catchment. 相似文献
428.
Based on the monthly sunspot numbers (SSNs), the solar-flare index (SFI), grouped solar flares (GSFs), the tilt angle of heliospheric current sheet (HCS), and cosmic-ray intensity (CRI) for Solar Cycles 21?–?24, a detailed correlation study has been performed using the cycle-wise average correlation (with and without time lag) method as well as by the “running cross-correlation” method. It is found that the slope of regression lines between SSN and SFI, as well as between SSN and GSF, is continuously decreasing from Solar Cycle 21 to 24. The length of regression lines has significantly decreased during Cycles 23 and 24 in comparison to Cycles 21 and 22. The cross-correlation coefficient (without time lag) between SSN–CRI, SFI–CRI, and GSF–CRI has been found to be almost the same during Cycles 21 and 22, while during Cycles 23 and 24 it is significantly higher between SSN–CRI and HCS–CRI than for SFI–CRI and GSF–CRI. Considering time lags of 1 to 20 months, the maximum correlation coefficient (negative) amongst all of the sets of solar parameters is observed with almost the same time lags during Cycles 21?–?23, whereas exceptional behaviour of the time lag has been observed during Cycle 24, as the correlation coefficient attains its maximum value with two time lags (four and ten months) in the case of the SSN–CRI relationship. A remarkably large time lag (22 months) between HCS and CRI has been observed during the odd-numbered Cycle 21, whereas during another odd cycle, Cycle 23, the lag is small (nine months) in comparison to that for other solar/flare parameters (13?–?15 months). On the other hand, the time lag between SSN–CRI and HCS–CRI has been found to be almost the same during even-numbered Solar Cycles 22 and 24. A similar analysis has been performed between SFI and CRI, and it is found that the correlation coefficient is maximum at zero time lag during the present solar cycle. The GSFs have shown better maximum correlation with CRI as compared to SFI during Cycles 21 to 23, indicating that GSF could also be used as a significant solar parameter to study the cosmic-ray modulation. Furthermore, the running cross-correlation coefficient between SSN–CRI and HCS–CRI, as well as between solar-flare activity parameters (SFI and GSF) and CRI is observed to be strong during the ascending and descending phases of solar cycles. The level of cosmic-ray modulation during the period of investigation shows the appropriateness of different parameters in different cycles, and even during the different phases of a particular solar cycle. We have also studied the galactic cosmic-ray modulation in relation to combined solar and heliospheric parameters using the empirical model suggested by Paouris et al. (Solar Phys.280, 255, 2012). The proposed model for the calculation of the modulated cosmic-ray intensity obtained from the combination of solar and heliospheric parameter gives a very satisfactory value of standard deviation as well as \(R^{2}\) (the coefficient of determination) for Solar Cycles 21?–?24. 相似文献
429.
In this chapter we present a detailed general relativistic formulation for the study of structure of perfect fluid disk rotating
around Kerr black hole.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
430.
H. P. Singh D. D. Tripathi S. C. Singh R. B. Mishra 《Astrophysics and Space Science》1987,139(2):413-419
This paper has been presented the geometric study and solutions of the electromagnetogeostrophic flows, and spatially the geometry of magnetic and current lines are discussed. 相似文献