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S. K. Biswas

Bio: S. K. Biswas is an academic researcher from University of Calcutta. The author has contributed to research in topics: Quantum dot & Light intensity. The author has an hindex of 8, co-authored 20 publications receiving 197 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the burning behavior of coals of Indian origin by TGA and in drop tube furnace (DTF) with particular emphasis on the role of macerals and their associations was investigated.

30 citations

Journal Article
TL;DR: Seed treatment with biocides was provided good protection of seed against seed borne infection, resulted enhanced germination of paddy seed and enhanced growth ofPaddy seedling.
Abstract: Bio-agents like Trichoderma harzianum, T. viride , bioformulation of Pseudomonas fluorescense and T. harzianum and botanical like garlic extract and Achook were tested against brown spot and sheath blight pathogens in vitro and also as seed dresser. In dual culture test T. harzianum and its bioformulation reduced mycelial growth by 55.3% 58.1% in D. oryzae and 42.7 % 43.0% in Rhizoctonia solani respectively. Seed treatment with biocides was provided good protection of seed against seed borne infection, resulted enhanced germination of paddy seed. The maximum 92% germination was recorded in seed treatment with bioformulation of T. harzianum followed by spore suspension of T. harzianum (89.3 %). The enhanced growth of paddy seedling has also been recorded as a result of the effect of seed treatment with biocides. The increase of 21.6 and 21.Q percent of shoot length and 25.8 and 25.1 of root length over control was recorded in seed treatment with bioformulation of T. harzianum and P. fluorescense respectively.

27 citations

Journal ArticleDOI
TL;DR: In this article, a simple theoretical analysis of the effective electron mass (EEM) at the Fermi level for III-V, ternary and quaternary materials, on the basis of a newly formulated electron energy spectra in the presence of light waves whose unperturbed energy band structures are defined by the three-band model of Kane, is presented.
Abstract: We present a simple theoretical analysis of the effective electron mass (EEM) at the Fermi level for III–V, ternary and quaternary materials, on the basis of a newly formulated electron energy spectra in the presence of light waves whose unperturbed energy band structures are defined by the three-band model of Kane The solution of the Boltzmann transport equation on the basis of this newly formulated electron dispersion law will introduce new physical ideas and experimental findings under different external conditions It has been observed that the unperturbed isotropic energy spectrum in the presence of light changes into an anisotropic dispersion relation with the energy-dependent mass anisotropy In the presence of light, the conduction band moves vertically upward and the band gap increases with the intensity and colours of light It has been found, taking n-InAs, n-InSb, n-Hg1−xCdxTe and n-In1−xGaxAsyP1−y lattice matched to InP as examples, that the EEM increases with increasing electron concentration, intensity and wavelength in various manners The strong dependence of the effective momentum mass (EMM) at the Fermi level on both the light intensity and wavelength reflects the direct signature of the light waves which is in contrast with the corresponding bulk specimens of the said materials in the absence of photo-excitation The rate of change is totally band-structure-dependent and is influenced by the presence of the different energy band constants The well known result for the EEM at the Fermi level for degenerate wide gap materials in the absence of light waves has been obtained as a special case of the present analysis under certain limiting conditions, and this compatibility is the indirect test of our generalized formalism

23 citations

Journal ArticleDOI
TL;DR: In this paper, the thermoelectric power in the presence of a large magnetic field (TPM) in heavily doped III-V, II-VI, PbTe/PbSnTe, strained layer and HgTe/CdTe quantum dot superlattices (QDSLs) with graded structures was analyzed.
Abstract: We study theoretically the thermoelectric power in the presence of a large magnetic field (TPM) in heavily doped III–V, II–VI, PbTe/PbSnTe, strained layer and HgTe/CdTe quantum dot superlattices (QDSLs) with graded structures on the basis of newly formulated electron energy spectra and compare the same with that of the constituent materials. It has been found, taking heavily doped GaAs/Ga1−xAlxAs, CdS/CdTe, PbTe/PbSnTe, InAs/GaSb and HgTe/CdTe QDSLs as examples, that the TPM increases with increasing inverse electron concentration and film thickness, respectively, in different oscillatory manners and the nature of oscillations is totally band structure dependent. We have also suggested the experimental methods of determining the Einstein relation for the diffusivity–mobility ratio, the Debye screening length and the electronic contribution to the elastic constants for materials having arbitrary dispersion laws.

23 citations


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Journal ArticleDOI
TL;DR: In this article, a review of the highest performing blend systems is presented in order to identify key trends and provide perspective on current progress in the field, highlighting what is known to date on processes limiting device efficiency, an outlook on the most important challenges remaining to the field is provided.
Abstract: Over the last 5 years, research on the synthesis, device engineering, and device physics of solution-processed small molecule solar cells (SMSCs) has rapidly expanded. Improvements in molecular design and emergent device processing techniques have helped solution-processed SMSCs overcome earlier difficulties in controlling active layer morphology, such that many systems are now at—or approaching—10% power conversion efficiency. In this review, details of the highest performing blend systems are presented in order to identify key trends and provide perspective on current progress in the field. Among the best systems, a planarized molecular structure is prevalent, which can be achieved using large fused-ring moieties, intermolecular non-bonding interactions, and side chain engineering. To obtain efficient devices, the highest performing systems have been optimized through the careful combination of thermal and solvent annealing procedures. Even without additional processing, some systems have been able to obtain interconnected morphologies and efficient charge generation and charge transport. Ultimately, the design of more efficient materials also requires additional understanding of the device physics and loss mechanisms. After highlighting what is known to date on processes limiting device efficiency, an outlook on the most important challenges remaining to the field is provided.

367 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide an overview of research related to unburned carbon (UC) from coal combustion ashes, including factors affecting UC content in ash, methods of UC determination, UC separation techniques, different approaches in studying UC, and so on.

121 citations

Journal ArticleDOI
TL;DR: This review uses the architecture of a simulation model to position and prioritize knowledge gaps, assess the epidemiological consequences of disease management options on BS monocyclic processes and explore the impact changing production situations on this important disease.
Abstract: Rice brown spot (BS) is a chronic disease that affects millions of hectares of rice every growing season, grown by some of the most resource-poor farmers. Despite its widespread occurrence and impact, much still needs to be understood about BS. Reported yield losses in relative terms vary widely from 4 to 52 %. However, accurate, systematic estimates are lacking. BS is conventionally perceived as a secondary problem that reflects rice crops that experience physiological stresses, e.g. drought and poor soil fertility, rather than a true infectious disease. Much remains to be understood about the mechanisms leading to epidemics and crop losses. Quantitative and qualitative knowledge gaps exist in our understanding of the epidemiological processes, sources of resistance and biocontrol methods. In this review we identify several of these gaps, which if filled, could lead to a strong impact on the management of brown spot. We also use the architecture of a simulation model to position and prioritize these knowledge gaps, assess the epidemiological consequences of disease management options on BS monocyclic processes and explore the impact changing production situations on this important disease.

91 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of oxygen concentration, particle size, and heating rate on coal combustion characteristics under an O2/CO2 atmosphere were investigated, and the results indicated that the oxygen concentration played the most important role.
Abstract: The effects of oxygen concentration, particle size, and heating rate on the coal combustion characteristics under an O2/CO2 atmosphere were investigated. The results indicated that the oxygen concentration played the most important role. As the oxygen concentration increases, the ignition and burnout temperatures decrease and the comprehensive combustion property index S increases. Moreover, the improvement of the oxygen concentration intensified the effects of the other factors. The ignition mechanism changes from hetero-homogeneous type to homogeneous type as the oxygen concentration increases. The ignition and burnout temperatures decrease slightly as the mean particle size decreases, and the index S increases measurably as the mean particle size decreases. The heating rate has different effects on the ignition temperature, burnout temperature, and index S at different oxygen concentrations.

89 citations

Book ChapterDOI
TL;DR: In this article, the authors focus on the band structure of semiconductors and propose a variety of methods such as tight binding, pseudopotential, and k • p methods.

75 citations