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1.
In this paper we consider the time-dependent diffuse reflection and transmission problems for a homogeneous anisotropically-scattering atmosphere of finite optical depth and solve it by the principle of invariance. Also we consider the time-dependent diffuse reflection and transmission of parallel rays by a slab consisting of two anisotropic homogeneous layers, whose scattering and transmission properties are known. It is shown how to express the time-dependent reflected and transmitted intensities in terms of their components. In a manner similar to that given by Tsujita (1968), we assumed that the upward-directed intensities of radiation at the boundary of the two layers are expressed by the sum of products of some auxiliary functions depending on only one argument. Then, after some analytical manipulations, three groups of systems of simultaneous integral equations governing the auxiliary functions are obtained. 相似文献
2.
A solution of the transfer equation for coherent scattering in stellar atmosphere with Planck's function as a nonlinear function of optical depth, viz., $$B_v (T) = b_0 + b_1 {\text{ }}e^{ - \beta \tau } $$ is obtained by the method of discrete ordinates originally due to Chandrasekhar. 相似文献
3.
The general equation for radiative transfer in the Milne-Eddington model is considered here. The scattering function is assumed to be quadratically anisotropic in the cosine of the scattering angle and Planck's intensity function is assumed for thermal emission. Here we have taken Planck's function as a nonlinear function of optical depth, viz.,B
v(T)=b
o+b
1
e
–. The exact solution for emergent intensity from the bounding face is obtained by the method of the Laplace transform in combination with the Wiener-Hopf technique. 相似文献
4.
An approximate solution of the transfer equation for coherent scattering in stellar atmospheres with Planck's function as a nonlinear function of optical depth, viz.,
相似文献
5.
The equation of transfer for interlocked multiplets has been solved exactly by the method used by Busbridge and Stibbs (1954) for exponential form of the Planck functionB
v
(T)=b
0+b
1
e
–. 相似文献
6.
Heavy metals in freshly deposited sediments of the river Subernarekha, India: an example of lithogenic and anthropogenic effects 总被引:1,自引:0,他引:1
A. K. Upadhyay K. K. Gupta J. K. Sircar M. K. Deb G. L. Mundhara 《Environmental Geology》2006,50(3):397-403
Heavy metal distribution patterns in river sediments aid in understanding the exogenic cycling of elements as well as in assessing the effect of anthropogenic influences. In India, the Subernarekha river flows over the Precambrian terrain of the Singhbhum craton in eastern India. The rocks are of an iron ore series and the primary rock types are schist and quartzite. One main tributary, the Kharkhai, flows through granite rocks and subsequently flows through the schist and quartzite layers. The Subernarekha flows through the East Singhbhum district, which is one of India’s industrialised areas known for ore mining, steel production, power generation, cement production and other related activities. Freshly deposited river sediments were collected upstream and downstream the industrial zone. Samples were collected from four locations and analysed in <63-μm sediment fraction for heavy metals including Zn, Pb, Cd and Cu by anodic stripping voltammetry. Enrichment of these elements over and above the local natural concentration level has been calculated and reported. Sediments of the present study are classified by Muller’s geo-accumulation index (I
geo) and vary from element to element and with climatic seasons. During pre-monsoon period the maximum I
geo value for Zn is moderately to highly polluted and for Cu and Pb is moderately polluted, respectively, based on the Muller’s standard. Anthropogenic, lithogenic or cumulative effects of both components are the main reasons for such variations in I
geo values. The basic igneous rock layer through which the river flows or a seasonal rivulet that joins with the main river may be the primary source for lithogenic components. 相似文献
7.
S. K. Deb M. H. Manghnani K. Ross R. A. Livingston P. J. M. Monteiro 《Physics and Chemistry of Minerals》2003,30(1):31-38
A Raman scattering and X-ray diffraction study of the thermal decomposition of a naturally occurring, ettringite-group crystal
is presented. Raman spectra, recorded with increasing temperature, indicate that the thermal decomposition begins at ≈55 °C,
accompanied by dehydration of water molecules from the mineral. This is in contrast to previous studies that reported higher
temperature breakdown of ettringite. The dehydration is completed by 175 °C and this results in total collapse of the crystalline
structure and the material becomes amorphous. The Raman scattering results are supported by X-ray diffraction results obtained
at increasing temperatures.
Received: 9 July 2001 / Accepted: 14 August 2002 相似文献
8.
A. Chakraborty H. C. Upadhyaya O. P. Sharma S. K. Deb 《Meteorology and Atmospheric Physics》2003,83(3-4):221-236
Summary ?A newly developed ocean general circulation model has been tested and verified with some idealized experiments. Generally
two types of idealized experiments have been done here. First types are called as “symmetric experiments” and second types
are called as “transport experiments”. The first types of experiment help to correct the model core and any deficiency from
boundary conditions. The second types of experiment are the type of validation experiment. In both the experiments there are
no continents, so in the first type of experiments where symmetric forcings are provided one can expect that model should
maintain the symmetric nature. In the second type of experiments one can expect that model should respond correctly to the
wind forcings, if no wind curl is present in the wind forcing there will be no circulation in the extratropics and if there
is no wind the equator there will be no circulation. The model reproduces the possible envisaged results of these experiments
and gives the confidence for performing the realistic integration.
Received February 20, 2002; accepted July 7, 2002
Published online: February 20, 2003 相似文献
9.
We have analyzed the chemical composition and boron isotope composition of tourmaline from tourmalinites, granite and a quartz-tourmaline
vein from the Deri ore zone and from a pegmatitic band in the Rampura-Agucha ore body. These two Proterozoic massive sulfide
deposits occur in the Aravalli-Delhi orogenic belt, Rajasthan, northwest India. Tourmaline from stratiform tourmalinites closely
associated with the massive sulfides in the Deri deposit have preserved their original chemical compositions despite regional
and thermal metamorphism in the area. These tourmalines have low Fe/(Fe + Mg) ratios (0.19–0.30; mean 0.26) that suggest formation
close to the sediment-sea water interface. The δ11B values (−15.5 and −16.4‰) are compatible with boron derived from leaching of argillaceous sediments and/or felsic volcanics
underlying the original massive sulfide deposit during its formation. Boron isotope compositions measured in tourmaline from
a post-ore granite and quartz-tourmaline vein in the Deri deposit indicate that boron in these tourmalines was derived from
the tourmalinites produced during ore formation. The boron isotope systematics of a coarse brown tourmaline crystal from a
pegmatitic band on the hanging wall contact of the Rampura-Agucha deposit indicate that 45 ± 25% of the boron within the original
tourmaline was lost during upper amphibolite facies regional metamorphism.
Received: 3 April 1996 / Accepted: 11 April 1996 相似文献
10.
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