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131.
We have obtained a solution of the Dirac equation near the horizon of a Kerr-Newman black hole and compared it with the solution of the Klein-Gordon equation. We first generalized the work of LIU Liao and XU Dian-yan for a quasi-extreme Kerr black hole to a quasi-extreme Kerr-Newman black hole, then further generalized to a general Kerr-Newman black hole, and thereby verified that the Dirac particles emitted by a general Kerr-Newman black hole do have a black-body energy spectrum. 相似文献
132.
Field observations of suspended particulate matter (SPM) in the Bohai Bay, China have not been widely reported. The aim of this paper is to describe the horizontal and vertical distribution of mass and volume concentrations of SPM, respectively, based on observed data at 312 stations in the northern Bohai Bay during summer of 2006. A numerical model ECOMSED coupled with a sediment transport module was also established to further discuss the mechanism of the thermocline effect on the vertical distribution of SPM. The mass concentrations of SPM exhibited high inshore values and low offshore values in the horizontal distribution; while in the vertical direction, characteristics of the volume concentration of SPM can be divided into two types: one with a sharp peak at depth of 10–15 m and another without. The peak value at the depth of the thermocline was resulted from concentrated phytoplankton. A numerical experiment further displayed that the thermocline can also prevent particles from being resuspended upward. 相似文献
133.
For the future development of Chinese Giant Solar Telescope (CGST) in Western China, a new sky brightness monitor (SBM) has been produced for the site survey for CGST. To critically examine the performance and sensitivity of SBM, we used it in the observation of the annular solar eclipse in Dali City, Yunnan, on 15 January 2010. The observation met good weather conditions with an almost clear sky during the eclipse. The SBM measurement translates into the solar illuminance changes at a level of 2.4×10?4 I?s?1 during the eclipse. The time of the minimal sky brightness in the field of view (FOV) is found consistent with the time of maximum eclipse. Two local sky regions in the FOV are chosen to make a time series of the calibrated skylight profiles. The evolution of the sky brightness thus calibrated also shows good consistency with the eclipse, particularly between the second and the third contacts. The minimal sky brightness in each local sky region took place within half a minute from the corresponding predicted contact time. Such small time delays were mainly caused by occasional cirri. The minimal sky brightness measured during the eclipse is a few millionths of I ?? with standard deviation of 0.11 millionths of I ??. The observation supports that the single-scattering process (optically thin conditions) is the main contributor to the atmospheric scattering. We have demonstrated that many important aerosol optical parameters can be deduced from our data. We conclude that the new SBM is a sensitive sky photometer that can be used for our CGST and coronagraph site surveys. 相似文献
134.
Li-Hong Geng Cheng-Ming Tan Yi-Hua Yan Bao-Lin Tan Dong-Hao Liu Jin-Ping Dun 《天文和天体物理学研究(英文版)》2021,(6):219-228
This work analyzes the annual fluctuation of the observation data of the Mingantu Solar radio Telescope(MST) in S, C and X bands. It is found that the data vary with local air temperature as the logarithmic attenuation of equipment increases with temperature and frequency. A simplified and effective calibration method is proposed, which is used to calibrate the MST data in 2018–2020, while the correction coefficients are calculated from data in 2018–2019. For S, C and X bands, the root mean square errors of one polarization are 2.7, 5.7 and 20 sfu, and the relative errors are 4%, 6% and 8% respectively. The calibration of MUSER and SBRS spectra is also performed. The relative errors of MUSER at 1700 MHz,SBRS at 2800 MHz, 3050 MHz and 3350 MHz are 8%, 8%, 11% and 10% respectively. We found that several factors may affect the calibration accuracy, especially at X-band. The method is expected to work for other radio telescopes with similar design. 相似文献
135.
The dynamical properties of electromagnetic (EM) waves in ultra-relativistic electron-positron (EP) plasmas are analytically investigated on the basis of the nonlinear governing equations obtained from a kinetic way. It is shown that the EM wave envelope will collapse and be trapped into a localized region for the modulation interaction with low frequency density variation induced by ponderomotive force. The correlation between the localized strong wave field and the pulsar radio emission is discussed. 相似文献
136.
137.
渤海湾北岸晚新生代沉积环境和沉积体系不仅是区域水文地质、工程地质的基础,也为古近纪沉积模式提供“将今论古”的依据。本文依据沉积物色度和粒度,以及沉积物岩性、结构和构造等,将渤海湾北岸TZ02孔划分了6个沉积组合、4个沉积阶段:1)2.10~3.22Ma,沉积组合Ⅰ和Ⅱ,湖盆填充期,发育湖相-泛滥平原相或湖相-曲流河相,该时期处于构造稳定期,干冷气候时期发育河流相、泛滥平原相,湿润气候时期发育湖泊相。2)1.33~2.10Ma,沉积组合Ⅲ,湖盆开始发育期,主要为浅湖相,仅有少量砂体,下部多有机质,上部多钙质淀积结核,指示了盆山之间的构造分异后,湖泊初始发育的特征。3)0.62~1.33Ma,沉积组合Ⅳ,湖盆扩张期,以湖相为主,多砂体,且有短期湖泊水位变浅和成陆过程;指示了盆山构造分异后,盆地加速沉降,湖盆扩张;山体隆起、河流下切,盆地中湖相砂体增多;此时TZ02孔附近为湖相中心,BG10孔为湖泊边缘。4)0~0.62Ma,沉积组合Ⅴ和Ⅵ,湖泊填充期,BG10孔为湖相的沉积中心,而TZ02孔为湖泊的边缘,接受滦河迁移摆动后的沉积物;中更新世后,构造沉降形成湖相,而间冰期发育海相,埋深0~22.5m的海相-河流相更直接地反映了末次冰消期海平面变化过程。
相似文献138.
一种改进的基于非高斯性最大化的预测反褶积算法 总被引:2,自引:1,他引:2
The predictive deconvolution algorithm (PD), which is based on second-order statistics, assumes that the primaries and the multiples are implicitly orthogonal. However, the seismic data usually do not satisfy this assumption in practice. Since the seismic data (primaries and multiples) have a non-Gaussian distribution, in this paper we present an improved predictive deconvolution algorithm (IPD) by maximizing the non-Gaussianity of the recovered primaries. Applications of the IPD method on synthetic and real seismic datasets show that the proposed method obtains promising results. 相似文献
139.
Bouchet in 1963 hypothesized that for large homogeneous land surface with minimum advection of heat and moisture, there exists
a 1:1 complementary relationship of potential and actual evaporation coupled through land-atmosphere feedbacks. The complementary
relationship has been widely used to estimate regional actual evaporation and explain the pan evaporation paradox. We examine
the standardized potential evaporation (potential evaporation divided by wet environment evaporation) at 102 observatories
at different elevations across China. Generally, the relationship is appropriate at the low elevations (<1000 m). With the
increase of elevation, vapor transfer power becomes much less than radiation energy budget because of lower vapor pressure
deficit and stronger global solar radiation. As a result, at the high elevations (over 1000 m), the excess energy resulted
by limited moisture availability is not enough to be converted into drying power of the air. This result suggests that the
complementary relationship is asymmetric at the high elevations.
Supported by the Presidential Special Award Foundation, the Chinese Academy of Sciences (Grant No. O7R70020SD) and the National
Key Technology R & D Program (Grant No. 2006BAC08B0408) 相似文献
140.