排序方式： 共有25条查询结果，搜索用时 733 毫秒
11.
In this paper, we consider an exact vacuum solution of the Kaluza-Klein (KK) theory, which describes nonrotating KK black holes. We investigate general properties of geodesic motion in the space-time and calculate the effective potential for null geodesics. The thermodynamical quantities as well as the gravitational lensing of the solution is calculated. We illustrate that the Carter-Penrose diagram for different parameter values resembles the Schwarzschild-like, naked and charged solutions. 相似文献
12.
We present observations and light curve analysis of the eclipsing binary R CMa in the narrow band filters v and b. Observations were made during 1993 at Biruni Observatory and the light curves have been analyzed using the Wilson-Devinney
light curve interpretation program. Assuming a semi-detached configuration for R CMa, the parameters i, Ω1, L
1, T
2 and A
2 were adjusted for the best fit between the synthesized light curves and observations. Both light curves were fitted well
with a lower value of bolometric albedo than what would be expected for a normal cool star with a convective envelope. The
masses of the primary and secondary components and the absolute dimensions of the stars have been calculated using the derived
relative dimensions from Wilson-Devinney codes and the spectroscopic observations. 相似文献
13.
We have calculated the equation of state of the neutron star matter and some of its properties for a wide range of nucleon-nucleon
potentials using the lowest order constrained variational (LOCV) method. It turns out that for the UV
14+TNI potential, the proton fraction exhibits a peak and falls off at high densities. The equation of state with the UV
14+TNI potential is seen to be much harder than those with other potentials. The polytropic behaviour of the neutron star matter
with various potentials are discussed. Compared with the other methods, the LOCV results show good agreement for densities
below 0.7 fm
-3. Above this density, however, the differences with other methods are appreciable. 相似文献
14.
Ghasem Nabatian Majid Ghaderi Farahnaz Daliran Nematollah Rashidnejad‐Omran 《Resource Geology》2013,63(1):42-56
The Sorkhe‐Dizaj iron oxide–apatite deposit in the Cenozoic Alborz‐Azarbaijan magmatic belt, NW Iran, is hosted mainly by a Late Eocene to Oligocene quartz‐monzonitic body, and subordinately in the Eocene volcanic and volcanoclastic sequences. The Sorkhe‐Dizaj intrusive body is an I‐type granitoid of the calc‐alkaline series. Mineralization is associated with actinolization, K‐feldspar, sericitic, propylitic, and tourmaline alteration types. The orebodies are massive, banded, stockwork, and breccia in shape and occur mainly along the fault zones within the quartz‐monzonitic intrusion, volcanic, and volcanoclastic rocks. Ore minerals dominantly comprise magnetite, apatite, and monazite, as well as minor amounts of chalcopyrite, bornite, and pyrite. Four major paragenetic stages are discriminated in the mineralization including early, oxide, sulfide, and late stage. The Sorkhe‐Dizaj deposit is similar in the aspects of host rock lithology, alteration, and mineralogy to the Kiruna‐type deposits associated with minor Cu sulfide minerals. Spatial and temporal association of the mineralization with the Late Eocene–Early Oligocene quartz‐monzonite intrusive body suggests that the ore fluid was probably related to magmatic activity. 相似文献
15.
Mineral chemistry of a Cenozoic igneous complex,the Urumieh–Dokhtar magmatic belt,Iran: Petrological implications for the plutonic rocks 
下载免费PDF全文
下载免费PDF全文 Maryam Honarmand Nematollah Rashidnejad Omran Franz Neubauer Ghasem Nabatian Mohammad Hashem Emami Manfred Bernroider Jamshid Ahmadian Mohammad Ebrahimi Xiaoming Liu 《Island Arc》2016,25(2):137-153
The Niyasar plutonic complex, one of the Cenozoic magmatic assemblages in the Urumieh‐Dokhtar magmatic belt, was the subject of detailed petrographic and mineralogical investigations. The Niyasar magmatic complex is composed of Eocene to Oligocene mafic rocks and Miocene granitoids. Eleven samples, representing the major rock units in the Niyasar magmatic complex and contact aureole were chosen for mineral chemical studies and for estimation of the pressure, temperature, and oxygen fugacity conditions of mineral crystallization during emplacement of various magmatic bodies. The analyzed samples are composed of varying proportions of quartz, plagioclase, K‐feldspar, hornblende, biotite, titanite, magnetite, apatite, zircon, garnet, and clinopyroxene. Application of the Al‐in‐hornblende barometer indicates pressures of around 0.2 to 0.4 kbar for the Eocene–Oligocene mafic bodies and around 0.5 to 1.7 kbar for the Miocene granitoids. Hornblende‐plagioclase thermometry yields relatively low temperatures (661–780 °C), which probably reflect late stage re‐equilibration of these minerals. The assemblage titanite–magnetite–quartz as well as hornblende composition were used to constrain the oxygen fugacity and H2O content during the crystallization of the parent magmas in the Miocene plutons. The results show that the Miocene granitoids crystallized from magmas with relatively high oxygen fugacity and high H2O content (~5 wt% H2O). The Miocene granitoids show similar range of oxygen fugacity, H2O contents and mineral chemical compositions, which indicate a common source for their magmas. Although the crystallization pressures of the Miocene plutons discriminate various categories of plutonic bodies emplaced at depths of about 5.7–6.5 km (Marfioun pluton), about 4.2 km (Ghalhar pluton) and 1.9–2.3 km (Poudalg pluton), they were later uplifted to the same level by vertical displacement of faults. The emplacement depths of the Niyasar plutons suggest that the central part of the Urumieh‐Dokhtar magmatic belt has experienced an uplift rate of ca. 0.25–0.4 mm/yr from the Miocene onwards. 相似文献
16.
Nematollah Rachidnejad-Omran Mohammad Hachem Emami Mossaïeb Sabzehei Ebrahim Rastad Herv Bellon Alain Piqu 《Comptes Rendus Geoscience》2002,334(16)
A detailed analysis of metamorphic complexes outcropping in the Muteh area in central Iran leads to establish the regional stratigraphical column, and to propose a Palaeozoic age for the metamorphic protolith that mainly consists of volcano-sedimentary units. 40K---40Ar ages for minerals suggest the Mesozoic age of the metamorphic amphiboles and the Palaeocene ones for a late or even post metamorphic bimodal magmatism. To cite this article: N. Rachidnejad-Omran et al., C. R. Geoscience 334 (2002) 1185–1191. 相似文献
17.
We present new photoelectric observations of the eclipsing binary system AB Cas, together with an analysis of the light curves.
Using the available times of light minimum reported in the literature together with our own minima, period changes are monitored,
and the possible third-body parameters are obtained. The absolute properties of the system and the delta-Scuti behavior of
the primary are also discussed. 相似文献
18.
Time-dependent wormhole solutions are found which evolve in a cosmological background. Solutions are presented both for GR
and Brans-Dicke field equations. Conditions are derived for the supporting matter to be non-exotic. The traceless energy-momentum
tensor needed to support the geometry is in the form of an anisotropic fluid. Far from the wormhole, the equation of state
rapidly approaches that of an isotropic perfect fluid with p = 1/3 ρ. For the BD wormholes we obtain ρ = 0everywhere, except for the π = const. limit, in which case the GR results are
reproduced.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
B and V photometry of the eccentric eclipsing binary DI Her is reported, with the aim of contributing to a more accurate determination
of the timings required for the ongoing apsidal motion studies. The resulting apsidal motion rate is close to the one reported
earlier by Khodykin and Volkov (1989), Guinan, Marshal and Maloney (IBVS 4101), and Yildiz et al. (2000).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
H wide and narrow-band photoelectric observations of the eclipsing binary R CMa were made at the Biruni Observatory between 18 February to 2 March, 1983. The light curves obtained from the observations are analysed according to Kopal's method for the orbital elements by using frequency-domain techniques. A total of obvervations was secured and light curves were formed from these data. From the available evidence it appears likely that an exchange has taken place on the angle of the first contact and is probably continuing at the present time in the system. New geometric and photometric elements are derived and new value for the angle of the first contact is also given.Contribution No. 11, Biruni Observatory. 相似文献