This paper reports on the effect of various micropropagation factors of Gmelina arborea Roxb. through multiple shoot induction. Factors like the source and age of explants, plant growth regulators (PGRs), media comp...This paper reports on the effect of various micropropagation factors of Gmelina arborea Roxb. through multiple shoot induction. Factors like the source and age of explants, plant growth regulators (PGRs), media composition, and carbon source affected multiple shoot-ing in the present study. Among all the explants used, only shoot tips derived from one, two, and three week old seedlings could form multiple shoots. Besides, the formation of multiple shoots depended on the con-centration and combination of PGRs. Among all the PGRs, BAP (6-benzylaminopurine) alone gave the highest regeneration efficiency. Simi-larly, IBA (Indole-3-butyric acid) was the most efficient PGR in inducing root formation in the microshoots. Media composition and carbon source also affected the regeneration efficiency. MS (Murashige and Skoog medium) proved to be the best media for regeneration followed by B5, SH (Schenk and Hilderbrandt medium) and WPM (Woody plant medium) in that order. Similarly, among sugars, only sucrose and glucose sup-ported induction of microshoots. Based on this study we recommend the use of glucose in place of sucrose in MS medium for maximum regenera-tion efficiency.展开更多
We have synthesized a series of single-composition emission Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) phosphor by traditional solid state reactions and novel combustion method. Formation of compound was confirmed by X-ray diffract...We have synthesized a series of single-composition emission Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) phosphor by traditional solid state reactions and novel combustion method. Formation of compound was confirmed by X-ray diffraction analysis. The photoluminescence(PL) emission spectra were observed at 376 nm when excited around 322 nm for the various concentrations in both cases. The PL emission spectra of phosphors showed strong Ce^(3+)emission due to the 5d → 4f transition of Ce^(3+)ions. The Ce^(3+)emission intensity in Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) prepared by combustion was higher than that of solid state reactions.展开更多
Eruptions of lava flows of Deccan large igneous province straddled the Cretaceous-Palaeogene boundary (K-Pg). Sediments associated at different stratigraphic levels within the lava piles of Deccan volcanic sequences (...Eruptions of lava flows of Deccan large igneous province straddled the Cretaceous-Palaeogene boundary (K-Pg). Sediments associated at different stratigraphic levels within the lava piles of Deccan volcanic sequences (DVS) are mainly terrestrial. We studied the sediments of Eastern and Central Deccan Volcanic Province, and the Malwa Plateau for tracking changes in reptilian tetrapods across the volcanism. The reptiles are mainly represented by abelisaurid-titanosaurid dinosaurs, Alethinophidia madtsoiia snakes, Notosuchian crocodylomorph Simosuchus, bothremydid Kurmademydinae turtles and Anguimorph and Scincomorphs lizards. The evidences suggest that the non-avian dinosaurs were adversely affected by the arrival of the first volcanic flows locally in the province either within C30N or C29R Maastrichtian. The abelisaurid theropods became extinct whereas a single or two species of titanosauriforme dinosaurs survived but eventually became extinct at least 350 ky before the K-Pg boundary with increasing volcanism. The madtsooid snakes and crocodylimorphs were also adversely affected with decline in their diversity and abundance, whereas the Bothremydid turtles survived the initial onslaught of Deccan volcanism and continued across the K-Pg boundary.展开更多
The late Archean Dharwar Craton is an important part of the Archean and Proterozoic terrains in Peninsular India.Dharwar Craton consists of Western and Eastern Blocks,separated by the Chitradurga Shear Zone.Eastern
Supervised classification of hyperspectral images is a challenging task because of the higher dimensionality of a pixel signature. The conventional classifiers require large training data set;however, practically limi...Supervised classification of hyperspectral images is a challenging task because of the higher dimensionality of a pixel signature. The conventional classifiers require large training data set;however, practically limited numbers of labeled pixels are available due to complexity and cost involved in sample collection. It is essential to have a method that can reduce such higher dimensional data into lower dimensional feature space without the loss of useful information. For classification purpose, it will be useful if such a method takes into account the nature of the underlying signal when extracting lower dimensional feature vector. The lifting framework provides the required flexibility. This article proposes the adaptive lifting wavelet transform to extract the lower dimensional feature vectors for the classification of hyperspectral signatures. The proposed adaptive update step allows the decomposition filter to adapt to the input signal so as to retain the desired characteristics of the signal. A three-layer feed forward neural network is used as a supervised classifier to classify the extracted features. The effectiveness of the proposed method is tested on two hyperspectral data sets (HYDICE & ROSIS sensors). The performance of the proposed method is compared with first generation discrete wavelet transform (DWT) based feature extraction method and previous studies that use the same data. The indices used for measuring performance are overall classification accuracy and Kappa value. The experimental results show that the proposed adaptive lifting scheme (ALS) has excellent results with a small size training set.展开更多
Here we report first ever study on acoustical evaluation of Kanheri Caves located in Sanjay Gandhi National Park,Mumbai(Maharashtra,India).These caves are dated to a period between 2nd century BCE to 7th century CE.In...Here we report first ever study on acoustical evaluation of Kanheri Caves located in Sanjay Gandhi National Park,Mumbai(Maharashtra,India).These caves are dated to a period between 2nd century BCE to 7th century CE.In this study we used an ambisonic recorder to capture Impulse Response,which carries acoustic signature of the place.Out of total 109 caves 41 were surveyed in available time.Out of those reverberant environment was noted in 12 caves.Measurements were made only in 3 caves(Cave Nos.1,3,11)which are important.In the beginning we carried out an FFT analysis.We then studied room acoustic parameters like Reverberation Time,Early Decay Time,Clarity,Definition,etc.,based on the measurement of Impulse response.Cave No.3 have high value of reverberation time,compared to other.Therefore it also have lower clarity compared to others.It is properties needs to be compared with similar structures(chaityas)in Maharashtra(at Ajanta,Ellora,Nashik,Junnar,etc.)and elsewhere in India.It is worthwhile to carry out further research in Cave No.3 with more sophisticated instruments as well as 3D modeling.Since the experiment was performed with receiver at only one position,we also suggest to carry out experiment with receiver at multiple positions and then comparing them.展开更多
The enormous eruptive volume of India's Deccan continental flood basalts has been linked to global mass extinction at Cretaceous-Paleogene boundary and destablilisation of both marine and terrestrial ecosystems be...The enormous eruptive volume of India's Deccan continental flood basalts has been linked to global mass extinction at Cretaceous-Paleogene boundary and destablilisation of both marine and terrestrial ecosystems before and after the Chicxulub bolide impact. Deccan Volcanic Province(DVP) currently covers around 500 000 km^2 of land between latitude 15°10′-24°30′N and longitude 70°10′-82°10′E over central India towards the west coast. The pre-erosional volume is estimated at around 1.6 million km^3 which is one of the largest volcanic eruptions on the Earth. The Deccan lava flows in geographically separated areas in DVP are considered to have separate sources and sites of eruptions and were outpoured in different magnetochrons viz. C30 n to C28 n of Maastrichtian to Paleocene. The Deccan volcanic sequences(DVS) in different provinces are associated with(i) sediments deposited before the arrival(Ground Zero) of the first lava flows-designated as infratrappean or Lameta sediments and(ii) sediments between the lava flows deposited during the period of quiescence at different stratigraphic levels designated as intertrappean(interflow) sediments. The Ground Zero Lameta sediments are the major dinosaur bearing sediments deposited in six inland basins viz. 1. Balasinor-Jhabua;2. Sagar;3. Jabalpur;4. Ambikapur-Amarkantak;5. Salburdi;6. Nand-Dongargaon. The sediments represent mainly the terrestrial ecosystems destabilised by the volcanism and they record history of biotic and environmental changes impacted by the volcanism across the Deccan volcanic eruptions. The titanosaurs, crocodylimorphs and bothremydid turtles survived across the first flows in the region in the C30 n. The skeletal remains of the surviving reptiles are preserved in the Deccan volcanic associated intertrappean lake sediments at different stratigraphic levels higher-up in the sequence. Locally, in the Malwa region the Scincomorp and Anguimorph lizards make their first appearance during the earlier phase of volcanic eruptions in C30 n wherein their well preserved bones are found in the intertrappean/inter lsva lake sediments deposited between the lava flows. The lizard fauna is indicated to have better flourished after the initial Deccan eruptions possibly owing to increased humidity.展开更多
The present paper deals with the determination of quasi-static thermal stresses due to an instantaneous point heat source of strength g_(pi) situated at certain circle along the radial direction of the circular plate ...The present paper deals with the determination of quasi-static thermal stresses due to an instantaneous point heat source of strength g_(pi) situated at certain circle along the radial direction of the circular plate and releasing its heat spontaneously at time t=τ.A circular plate is considered having arbitrary initial temperature and subjected to time dependent heat flux at the fixed circular boundary of r=b.The governing heat conduction equation is solved by using the integral transform method,and results are obtained in series form in terms of Bessel functions.The mathematical model has been constructed for copper material and the thermal stresses are discussed graphically.展开更多
Objective:To explore the effect of herbal polyphenolics on filariasis in vitro.Methods:Two herbal extracts,methanolic extracts of roots of Vitex negundo Linn.(Nirgundi) and leaves of Aegle marmelos Juss.(Beal) in ...Objective:To explore the effect of herbal polyphenolics on filariasis in vitro.Methods:Two herbal extracts,methanolic extracts of roots of Vitex negundo Linn.(Nirgundi) and leaves of Aegle marmelos Juss.(Beal) in different concentrations ranging from 40-80 ng/mL were tested for their antifilarial activity either alone or in combination with diethyl carbonate(DEC)(300μg/mL) and/or H<sub>2</sub>O<sub>2</sub>(0.5 mM).Results:Combination of DEC and each extract had significant anti-filarial effect.And fractions of both extracts were not effective as crude herbal extract.Conclusions: Such unique pharmacodynamics reported in this study might provide new drug development stratagem against filariasis.展开更多
An attempt has been made to study the uncoupled thermoelastic response oI tr^lc~ cylmaer of length 2h in which heat sources are generated according to the linear function of the temperature, with boundary conditions o...An attempt has been made to study the uncoupled thermoelastic response oI tr^lc~ cylmaer of length 2h in which heat sources are generated according to the linear function of the temperature, with boundary conditions of the radiation type. This approach is based upon integral transform techniques, to find out the thermoelastic solution. The results are obtained in terms of Bessel functions in the form of infinite series.展开更多
BaGdB9O16:Eu^3+ and Ba(Gd,Ln)B9O16:Eu^3+(Ln=La, Y) phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy(SEM) and photoluminescence properties were i...BaGdB9O16:Eu^3+ and Ba(Gd,Ln)B9O16:Eu^3+(Ln=La, Y) phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy(SEM) and photoluminescence properties were investigated. The as-synthesized BaGdB9O16:Eu^3+ and Ba(Gd,Ln)B9O16:Eu^3+(Ln=La, Y) phosphors showed strong red emission under ultraviolet light excitation. By partially substituting Gd^3+ by La^3+ and Y^3+ ions in the host BaGdB9O16:Eu^3+ materials, the maximum emission intensity was observed for the optimum composition of BaGd0.91La0.8B9O16Eu0.01 phosphor. The experimental results indicated that the Eu doped BaGdB9O16 and Ba(Gd,Ln)B9O16(Ln=La, Y) phosphors were promising red phosphors, which might find potential applications in near-UV excited LED lighting as well as display devices. Comparison of as-synthesized phosphors with standard phosphor used in CFL(compact fluorescent lamp) was also done. Energy transfer mechanism of Gd^3+ to Eu^3+ was also discussed in this paper.展开更多
The preparation of NaCaPO4 doped with rare earth (RE) ions Ce3+, Eu3+ and Dy3+ by combustion method was described. Under UV excitation (251 nm) of NaCaPO4:Ce3+ showsd emission (367 nm) in UV range. When NaC...The preparation of NaCaPO4 doped with rare earth (RE) ions Ce3+, Eu3+ and Dy3+ by combustion method was described. Under UV excitation (251 nm) of NaCaPO4:Ce3+ showsd emission (367 nm) in UV range. When NaCaPO4:Dy3+ phosphor was excited at 349 nm, the emission spectrum showed intense bands at 482 nm (blue) and 576 nm (yellow). In Eu activated NaCaPO4 phosphor, the emission spectrum showed a dominant peak at 594 nm (orange) while others were at 614 and 621 nm (red) when excited at 393 nm. The prepared phosphor was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) measurement. Thus, the photoluminescence behavior of NaCaPO4:Ce3+ was strongly suggested for scintillator. Likewise, Eu3+ and Dy3+ activated NaCaPO4 phosphors were recommended for near-UV white light-emitting diodes (LEDs).展开更多
The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object o...The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object occupying the space D: -a〈xSa; -b〈_y〈b; 0〈z〈h; with the known boundary conditions. Laplace and Finite Marchi-Fasulo transform techniques are used to determine the unknown temperature, temperature distribution, displacement and thermal stresses on upper plane surface of a thin rectangular object. The distributions of the considered physical variables are obtained and represented graphically.展开更多
This paper deals with study of generalized Chaplygin gas model with dynamical gravitational and cosmological constants. In this paper a new set of exact solutions of Einstein field equations for spatially homogeneous ...This paper deals with study of generalized Chaplygin gas model with dynamical gravitational and cosmological constants. In this paper a new set of exact solutions of Einstein field equations for spatially homogeneous and anisotropic Bianchi type Ⅰ space-time have been obtained. The solutions of the Einstein's field equations are obtained by considering(i) the power law relation between Hubble parameter H and scale factor R and(ii) scale factor of the form R =-1/t + t^2, t > 1. The assumptions lead to constant and variable deceleration parameter respectively. The physical and dynamical behaviors of the models have been discussed with the help of graphical representations. Also we have discussed the stability and physical acceptability of solutions for solution type-Ⅰ and solution type-Ⅱ.展开更多
文摘This paper reports on the effect of various micropropagation factors of Gmelina arborea Roxb. through multiple shoot induction. Factors like the source and age of explants, plant growth regulators (PGRs), media composition, and carbon source affected multiple shoot-ing in the present study. Among all the explants used, only shoot tips derived from one, two, and three week old seedlings could form multiple shoots. Besides, the formation of multiple shoots depended on the con-centration and combination of PGRs. Among all the PGRs, BAP (6-benzylaminopurine) alone gave the highest regeneration efficiency. Simi-larly, IBA (Indole-3-butyric acid) was the most efficient PGR in inducing root formation in the microshoots. Media composition and carbon source also affected the regeneration efficiency. MS (Murashige and Skoog medium) proved to be the best media for regeneration followed by B5, SH (Schenk and Hilderbrandt medium) and WPM (Woody plant medium) in that order. Similarly, among sugars, only sucrose and glucose sup-ported induction of microshoots. Based on this study we recommend the use of glucose in place of sucrose in MS medium for maximum regenera-tion efficiency.
文摘We have synthesized a series of single-composition emission Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) phosphor by traditional solid state reactions and novel combustion method. Formation of compound was confirmed by X-ray diffraction analysis. The photoluminescence(PL) emission spectra were observed at 376 nm when excited around 322 nm for the various concentrations in both cases. The PL emission spectra of phosphors showed strong Ce^(3+)emission due to the 5d → 4f transition of Ce^(3+)ions. The Ce^(3+)emission intensity in Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) prepared by combustion was higher than that of solid state reactions.
文摘Eruptions of lava flows of Deccan large igneous province straddled the Cretaceous-Palaeogene boundary (K-Pg). Sediments associated at different stratigraphic levels within the lava piles of Deccan volcanic sequences (DVS) are mainly terrestrial. We studied the sediments of Eastern and Central Deccan Volcanic Province, and the Malwa Plateau for tracking changes in reptilian tetrapods across the volcanism. The reptiles are mainly represented by abelisaurid-titanosaurid dinosaurs, Alethinophidia madtsoiia snakes, Notosuchian crocodylomorph Simosuchus, bothremydid Kurmademydinae turtles and Anguimorph and Scincomorphs lizards. The evidences suggest that the non-avian dinosaurs were adversely affected by the arrival of the first volcanic flows locally in the province either within C30N or C29R Maastrichtian. The abelisaurid theropods became extinct whereas a single or two species of titanosauriforme dinosaurs survived but eventually became extinct at least 350 ky before the K-Pg boundary with increasing volcanism. The madtsooid snakes and crocodylimorphs were also adversely affected with decline in their diversity and abundance, whereas the Bothremydid turtles survived the initial onslaught of Deccan volcanism and continued across the K-Pg boundary.
文摘The late Archean Dharwar Craton is an important part of the Archean and Proterozoic terrains in Peninsular India.Dharwar Craton consists of Western and Eastern Blocks,separated by the Chitradurga Shear Zone.Eastern
文摘Supervised classification of hyperspectral images is a challenging task because of the higher dimensionality of a pixel signature. The conventional classifiers require large training data set;however, practically limited numbers of labeled pixels are available due to complexity and cost involved in sample collection. It is essential to have a method that can reduce such higher dimensional data into lower dimensional feature space without the loss of useful information. For classification purpose, it will be useful if such a method takes into account the nature of the underlying signal when extracting lower dimensional feature vector. The lifting framework provides the required flexibility. This article proposes the adaptive lifting wavelet transform to extract the lower dimensional feature vectors for the classification of hyperspectral signatures. The proposed adaptive update step allows the decomposition filter to adapt to the input signal so as to retain the desired characteristics of the signal. A three-layer feed forward neural network is used as a supervised classifier to classify the extracted features. The effectiveness of the proposed method is tested on two hyperspectral data sets (HYDICE & ROSIS sensors). The performance of the proposed method is compared with first generation discrete wavelet transform (DWT) based feature extraction method and previous studies that use the same data. The indices used for measuring performance are overall classification accuracy and Kappa value. The experimental results show that the proposed adaptive lifting scheme (ALS) has excellent results with a small size training set.
文摘Here we report first ever study on acoustical evaluation of Kanheri Caves located in Sanjay Gandhi National Park,Mumbai(Maharashtra,India).These caves are dated to a period between 2nd century BCE to 7th century CE.In this study we used an ambisonic recorder to capture Impulse Response,which carries acoustic signature of the place.Out of total 109 caves 41 were surveyed in available time.Out of those reverberant environment was noted in 12 caves.Measurements were made only in 3 caves(Cave Nos.1,3,11)which are important.In the beginning we carried out an FFT analysis.We then studied room acoustic parameters like Reverberation Time,Early Decay Time,Clarity,Definition,etc.,based on the measurement of Impulse response.Cave No.3 have high value of reverberation time,compared to other.Therefore it also have lower clarity compared to others.It is properties needs to be compared with similar structures(chaityas)in Maharashtra(at Ajanta,Ellora,Nashik,Junnar,etc.)and elsewhere in India.It is worthwhile to carry out further research in Cave No.3 with more sophisticated instruments as well as 3D modeling.Since the experiment was performed with receiver at only one position,we also suggest to carry out experiment with receiver at multiple positions and then comparing them.
基金the Research Grant ( MoES / PO ( GEOSCI ) /49 /2015 ) of Ministry of Earth Sciences,Government of India,New Delhi
文摘The enormous eruptive volume of India's Deccan continental flood basalts has been linked to global mass extinction at Cretaceous-Paleogene boundary and destablilisation of both marine and terrestrial ecosystems before and after the Chicxulub bolide impact. Deccan Volcanic Province(DVP) currently covers around 500 000 km^2 of land between latitude 15°10′-24°30′N and longitude 70°10′-82°10′E over central India towards the west coast. The pre-erosional volume is estimated at around 1.6 million km^3 which is one of the largest volcanic eruptions on the Earth. The Deccan lava flows in geographically separated areas in DVP are considered to have separate sources and sites of eruptions and were outpoured in different magnetochrons viz. C30 n to C28 n of Maastrichtian to Paleocene. The Deccan volcanic sequences(DVS) in different provinces are associated with(i) sediments deposited before the arrival(Ground Zero) of the first lava flows-designated as infratrappean or Lameta sediments and(ii) sediments between the lava flows deposited during the period of quiescence at different stratigraphic levels designated as intertrappean(interflow) sediments. The Ground Zero Lameta sediments are the major dinosaur bearing sediments deposited in six inland basins viz. 1. Balasinor-Jhabua;2. Sagar;3. Jabalpur;4. Ambikapur-Amarkantak;5. Salburdi;6. Nand-Dongargaon. The sediments represent mainly the terrestrial ecosystems destabilised by the volcanism and they record history of biotic and environmental changes impacted by the volcanism across the Deccan volcanic eruptions. The titanosaurs, crocodylimorphs and bothremydid turtles survived across the first flows in the region in the C30 n. The skeletal remains of the surviving reptiles are preserved in the Deccan volcanic associated intertrappean lake sediments at different stratigraphic levels higher-up in the sequence. Locally, in the Malwa region the Scincomorp and Anguimorph lizards make their first appearance during the earlier phase of volcanic eruptions in C30 n wherein their well preserved bones are found in the intertrappean/inter lsva lake sediments deposited between the lava flows. The lizard fauna is indicated to have better flourished after the initial Deccan eruptions possibly owing to increased humidity.
文摘The present paper deals with the determination of quasi-static thermal stresses due to an instantaneous point heat source of strength g_(pi) situated at certain circle along the radial direction of the circular plate and releasing its heat spontaneously at time t=τ.A circular plate is considered having arbitrary initial temperature and subjected to time dependent heat flux at the fixed circular boundary of r=b.The governing heat conduction equation is solved by using the integral transform method,and results are obtained in series form in terms of Bessel functions.The mathematical model has been constructed for copper material and the thermal stresses are discussed graphically.
基金supported by the Grants under the Department of Biotechnology,India(DBT) Funded Project "Repository for the Filarial Parasites and Reagents"(NO. BT/INF/22/1/2007)
文摘Objective:To explore the effect of herbal polyphenolics on filariasis in vitro.Methods:Two herbal extracts,methanolic extracts of roots of Vitex negundo Linn.(Nirgundi) and leaves of Aegle marmelos Juss.(Beal) in different concentrations ranging from 40-80 ng/mL were tested for their antifilarial activity either alone or in combination with diethyl carbonate(DEC)(300μg/mL) and/or H<sub>2</sub>O<sub>2</sub>(0.5 mM).Results:Combination of DEC and each extract had significant anti-filarial effect.And fractions of both extracts were not effective as crude herbal extract.Conclusions: Such unique pharmacodynamics reported in this study might provide new drug development stratagem against filariasis.
基金University Grant Commission,New Delhi for providing the partial financial assistance under major research project scheme
文摘An attempt has been made to study the uncoupled thermoelastic response oI tr^lc~ cylmaer of length 2h in which heat sources are generated according to the linear function of the temperature, with boundary conditions of the radiation type. This approach is based upon integral transform techniques, to find out the thermoelastic solution. The results are obtained in terms of Bessel functions in the form of infinite series.
基金University Grants Commission (UGC), New Delhi, for sanctioning the leave under Faculty Improvement program (FIP) to carry out this research work
文摘BaGdB9O16:Eu^3+ and Ba(Gd,Ln)B9O16:Eu^3+(Ln=La, Y) phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy(SEM) and photoluminescence properties were investigated. The as-synthesized BaGdB9O16:Eu^3+ and Ba(Gd,Ln)B9O16:Eu^3+(Ln=La, Y) phosphors showed strong red emission under ultraviolet light excitation. By partially substituting Gd^3+ by La^3+ and Y^3+ ions in the host BaGdB9O16:Eu^3+ materials, the maximum emission intensity was observed for the optimum composition of BaGd0.91La0.8B9O16Eu0.01 phosphor. The experimental results indicated that the Eu doped BaGdB9O16 and Ba(Gd,Ln)B9O16(Ln=La, Y) phosphors were promising red phosphors, which might find potential applications in near-UV excited LED lighting as well as display devices. Comparison of as-synthesized phosphors with standard phosphor used in CFL(compact fluorescent lamp) was also done. Energy transfer mechanism of Gd^3+ to Eu^3+ was also discussed in this paper.
基金Project supported by University Grant Commission (UGC), New Delhi, India
文摘The preparation of NaCaPO4 doped with rare earth (RE) ions Ce3+, Eu3+ and Dy3+ by combustion method was described. Under UV excitation (251 nm) of NaCaPO4:Ce3+ showsd emission (367 nm) in UV range. When NaCaPO4:Dy3+ phosphor was excited at 349 nm, the emission spectrum showed intense bands at 482 nm (blue) and 576 nm (yellow). In Eu activated NaCaPO4 phosphor, the emission spectrum showed a dominant peak at 594 nm (orange) while others were at 614 and 621 nm (red) when excited at 393 nm. The prepared phosphor was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) measurement. Thus, the photoluminescence behavior of NaCaPO4:Ce3+ was strongly suggested for scintillator. Likewise, Eu3+ and Dy3+ activated NaCaPO4 phosphors were recommended for near-UV white light-emitting diodes (LEDs).
基金University Grant Commission,New Delhi for providing the partial financial assistance under major research project scheme
文摘The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object occupying the space D: -a〈xSa; -b〈_y〈b; 0〈z〈h; with the known boundary conditions. Laplace and Finite Marchi-Fasulo transform techniques are used to determine the unknown temperature, temperature distribution, displacement and thermal stresses on upper plane surface of a thin rectangular object. The distributions of the considered physical variables are obtained and represented graphically.
文摘This paper deals with study of generalized Chaplygin gas model with dynamical gravitational and cosmological constants. In this paper a new set of exact solutions of Einstein field equations for spatially homogeneous and anisotropic Bianchi type Ⅰ space-time have been obtained. The solutions of the Einstein's field equations are obtained by considering(i) the power law relation between Hubble parameter H and scale factor R and(ii) scale factor of the form R =-1/t + t^2, t > 1. The assumptions lead to constant and variable deceleration parameter respectively. The physical and dynamical behaviors of the models have been discussed with the help of graphical representations. Also we have discussed the stability and physical acceptability of solutions for solution type-Ⅰ and solution type-Ⅱ.