我国卤水溴资源及其开发前景展望   总被引：5，自引：0，他引：5       下载免费PDF全文

乌志明  温现明 《盐湖研究》2000,8(2):59-67

溴在自然界无独立的矿物 ,呈强分散性稀有元素 ,散布在地壳水圈里 ,以油气田地下卤水、盐湖卤水、矿场盐卤水含溴浓度相对较高。溴在国民经济的用途广泛 ,是我国紧缺物资 ,产不敷消。而我国卤水溴资源分布广泛 ,类型齐全 ,同时常伴有K、B、I、Li等多种有用组分。充分发挥各类卤水溴资源特点 ,提高卤水溴资源综合利用水平 ,其开发前景广阔  相似文献   

同仁双朋西金矿浮选尾矿中提铜扩大试验的研究          下载免费PDF全文

龙光明  康永峰 《盐湖研究》2000,8(2):22-28

在小试的工艺基础上 ,对双朋西金矿浮选后的尾矿进行铜、金回收扩大试验。对铜的浸取试验结果表明 ,本工艺对该尾矿具有较高的铜浸取率和回收率  相似文献   

The ionospheric effects in D-layer and solar proton precipitation zones during the 16 February 1984 event     

M. I. Beloglazov  G. P. Beloglazova  E. V. Vashenyuk  G. A. Petrova  O. I. Shumilov  V. A. Shishaev

I. N. Zabavina

V. I. Nesterov 《Planetary and Space Science》1990,38(12):1479-1486

The results of the geophysical and VLF (10–16 kHz) radio propagation measurements on the net of observatories during the solar proton event on 16 February 1984 are analysed. It is shown that the abnormal ionization region caused by solar protons consisted of two parts. One of them was the direct access zone in the middle and morning side of the polar cap, the other was the precipitation region of the quasi-trapped particles in the mid-day and evening sectors of the auroral zone. The probable profiles of the lower ionosphere electron density are determined from the VLF and satellite data of the energetic spectra at the maximum penetration. It is shown that the effective electron concentration at the height 45 km was close to 10³ cm−3</sup>.  相似文献</sup>   

Long term evolution of distant retrograde orbits in the Earth-Moon system   总被引：1，自引：0，他引：1  

Collin?BezroukEmail authorView author&#;s OrcID profile  Jeffrey?S.?Parker 《Astrophysics and Space Science》2017,362(9):176

This work studies the evolution of several Distant Retrograde Orbits (DROs) of varying size in the Earth-Moon system over durations up to tens of millennia. This analysis is relevant for missions requiring a completely hands off, long duration quarantine orbit, such as a Mars Sample Return mission or the Asteroid Redirect Mission. Four DROs are selected from four stable size regions and are propagated for up to 30,000 years with an integrator that uses extended precision arithmetic techniques and a high fidelity dynamical model. The evolution of the orbit’s size, shape, orientation, period, out-of-plane amplitude, and Jacobi constant are tracked. It has been found that small DROs, with minor axis amplitudes of approximately 45,000 km or less decay in size and period largely due to the Moon’s solid tides. Larger DROs (62,000 km and up) are more influenced by the gravity of bodies external to the Earth-Moon system, and remain bound to the Moon for significantly less time.  相似文献   

Secular tidal changes in lunar orbit and Earth rotation     

James?G.?WilliamsEmail authorView author&#;s OrcID profile  Dale?H.?Boggs 《Celestial Mechanics and Dynamical Astronomy》2016,126(1-3):89-129

Small tidal forces in the Earth–Moon system cause detectable changes in the orbit. Tidal energy dissipation causes secular rates in the lunar mean motion n, semimajor axis a, and eccentricity e. Terrestrial dissipation causes most of the tidal change in n and a, but lunar dissipation decreases eccentricity rate. Terrestrial tidal dissipation also slows the rotation of the Earth and increases obliquity. A tidal acceleration model is used for integration of the lunar orbit. Analysis of lunar laser ranging (LLR) data provides two or three terrestrial and two lunar dissipation parameters. Additional parameters come from geophysical knowledge of terrestrial tides. When those parameters are converted to secular rates for orbit elements, one obtains dn/dt = \(-25.97\pm 0.05 ''/\)cent\(^{2}\), da/dt = 38.30 ± 0.08 mm/year, and di/dt = ?0.5 ± 0.1 \(\upmu \)as/year. Solving for two terrestrial time delays and an extra de/dt from unspecified causes gives \(\sim \) \(3\times 10^{-12}\)/year for the latter; solving for three LLR tidal time delays without the extra de/dt gives a larger phase lag of the N2 tide so that total de/dt = \((1.50 \pm 0.10)\times 10^{-11}\)/year. For total dn/dt, there is \(\le \)1 % difference between geophysical models of average tidal dissipation in oceans and solid Earth and LLR results, and most of that difference comes from diurnal tides. The geophysical model predicts that tidal deceleration of Earth rotation is \(-1316 ''\)/cent\(^{2}\) or 87.5 s/cent\(^{2}\) for UT1-AT, a 2.395 ms/cent increase in the length of day, and an obliquity rate of 9 \(\upmu \)as/year. For evolution during past times of slow recession, the eccentricity rate can be negative.  相似文献   

Line-of-Sight Anisotropies in the Cosmic Dawn and Epoch of Reionization 21-cm Power Spectrum     

Suman?MajumdarEmail authorView author&#;s OrcID profile  Kanan?K.?Datta  Raghunath?Ghara  Rajesh?Mondal  T.?Roy?Choudhury  Somnath?Bharadwaj  Sk.?Saiyad?Ali  Abhirup?Datta 《Journal of Astrophysics and Astronomy》2016,37(4):32

The line-of-sight direction in the redshifted 21-cm signal coming from the cosmic dawn and the epoch of reionization is quite unique in many ways compared to any other cosmological signal. Different unique effects, such as the evolution history of the signal, non-linear peculiar velocities of the matter etc. will imprint their signature along the line-of-sight axis of the observed signal. One of the major goals of the future SKA-LOW radio interferometer is to observe the cosmic dawn and the epoch of reionization through this 21-cm signal. It is thus important to understand how these various effects affect the signal for its actual detection and proper interpretation. For more than one and half decades, various groups in India have been actively trying to understand and quantify the different line-of-sight effects that are present in this signal through analytical models and simulations. In many ways the importance of this sub-field under 21-cm cosmology have been identified, highlighted and pushed forward by the Indian community. In this article, we briefly describe their contribution and implication of these effects in the context of the future surveys of the cosmic dawn and the epoch of reionization that will be conducted by the SKA-LOW.  相似文献   

Characteristics of convection and overshooting in RGB and AGB stars     

Xiang-Jun Lai    Yan Li  National Astronomical Observatories/ Yunnan Observatory  Chinese Academy of Sciences  Kunming  China  Key Laboratory for the Structure  Evolution of Celestial Objects  China Graduate University of Chinese Academy of Sciences  Beijing  China. 《中国天文和天体物理学报》2011,(10)

Based on the turbulent convection model (TCM) of Li & Yang, we have studied the characteristics of turbulent convection in the envelopes of 2 and 5M⊙ stars at the red giant branch and asymptotic giant branch phases. The TCM has been successfully applied over the entire convective envelopes, including the convective unstable zone and the overshooting regions. We find that the convective motions become progressively stronger when the stellar models are located farther up along the Hayashi line. In the convect...  相似文献   

Mutual eclipses of J2 Europa by J1 Io observed at Yunnan Observatory in 2009     

Xi-Liang Zhang  Zhong Liu National Astronomical Observatories/ Yunnan Observatory  Joint Laboratory for Optical Astronomy  Chinese Academy of Sciences  Kunming  China  Graduate University of Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2011,(10)

Mutual events between natural satellites include mutual occultation and mutual eclipse. Mutual eclipse is another kind of mutual occultation as viewed from the center of the Sun instead of the Earth. Two mutual eclipses of J2 Europa by J1 Io (2009 Aug. 28 and Sept. 12) were observed at Yunnan Observatory during the PHEMU09 international campaign. We will calculate the astrometric data of these Galilean satellites by analyzing and fitting the light curves we obtained. The limb-darkening was considered during...  相似文献   

Associations of decimetric type Ⅲ bursts with coronal mass ejections and Hα flares     

Yuan Ma  De-Yu Wang  Jun Lin    Shuo Dai  Xue-Fei Zhang National Astronomical Observatories of China / Yunnan Astronomical Observatory  Chinese Academy of Sciences  Kunming  China Purple Mountain Observatory  Nanjing  China Harvard-Smithsonian Center for Astrophysics  Cambridge  MA  USA 《中国天文和天体物理学报》2010,10(5)

We present a statistical study of decimetric type Ⅲ radio bursts,coronal mass ejections(CMEs),and Hα flares observed in the period from July 2000 to March2005.In total,we investigated 395 decimetric type Ⅲ radio burst events,21% of which showed apparent correlation to CMEs that were associated with Hα flares.We noticed that the Hα flares which were strongly associated with CMEs were gradual events,and82% of them took place before CMEs appeared in the field of view of LASCO C2;that most of the CME-associated radio bursts started in the frequency range around750 MHz with a frequency drifting rate of several hundred MHz s-1,of which both positive and negative ones were recognized; and that the correlation of type Ⅲ radio bursts to CMEs without associated flares is fairly vague,less than 9%.  相似文献   

Infrared spectral evolution of carbon stars     

Pei-Sheng Chen  Xiao-Hong Yang  Hong-Guang Shan National Astronomical Observatories /Yunnan Observatory  Key Laboratory for the Structure  Evolution of Celestial Objects  Chinese Academy of Sciences  Kunming  China 《中国天文和天体物理学报》2010,10(4)

We collected almost all Highly Processed Data Products(HPDP)of ISO SWS01 spectra for the Galactic visual carbon stars,infrared carbon stars,extreme carbon stars and carbon-rich proto-planetary nebulae(PPNs).Those infrared spectra are primarily analyzed and discussed.It is shown that either spectral shapes/peaks,or main molecular/dust features are evidenced to change in the sequence of visual carbon stars,infrared carbon stars,extreme carbon stars and carbon-rich PPNs.Statistically,in this sequence,continua are gradually changed from blue to red and locations of spectral peaks of continua are also gradually changed from short wavelengths to long wavelengths.In addition,in this sequence,intensifies of main molecular/dust features are also gradually changed from prominent in the short wavelengths to prominent in the long wavelengths.Furthermore,from 2MASS and IRAS photometric data,the sequence is also proved.Results in this paper strongly support the previous suggestion for the evolution sequence of carbon-rich objects in our Galaxy,that is the sequence of visual carbon stars→infrared carbon stars→extreme carbon stars→carbon-rich PPNs.  相似文献