A liquid phase chemical bath deposition(LPCBD)method for deposition of PbS thin films is presented.The growth kinetics and reaction mechanism have been discussed.For the deposition,triethanolamine complex of lead acet...A liquid phase chemical bath deposition(LPCBD)method for deposition of PbS thin films is presented.The growth kinetics and reaction mechanism have been discussed.For the deposition,triethanolamine complex of lead acetate was allowed to react with aqueous thiourea solution.Glass micro-slides were used as the substrates.The deposition of PbS films was carried out under different growth parameters such as temperature,time,and reaction pH.The growth rate,under different conditions,was measured in terms of a terminal layer thickness and the possible reaction kinetics and mechanism is discussed.The optimum values of the parameters to produce good quality films are 60 min,80℃and 10.5±0.1.An EDS analysis showed that the film stoichiometry is dependent on the reaction pH and the films tend to be almost stoichiometric in high alkaline environment(>10.5).The PbS deposits appeared smooth,tightly adherent,uniform and reflecting with blackish-grey colour.The XRD studies showed crystalline cubic type of structure with preferred orientation along(200)plane.The calculated d-values,intensities of reflections and lattice parameter have excellent match with that of the JCPD data.The crystallite size is found to be few tens of nanometer.The surface morphology revealed by SEM showed that the crystallites are randomly oriented and are of different shapes and sizes.Majority of the crystallites appeared smaller and spherical in shape whereas,growth of some elongated irregular crystallites;bit larger in size and differing in shapes,have also been favoured.展开更多
Carbon based nanomaterials are acknowledged for their admirable optical,electrical,mechanical characteristics and broad class of applications.Choice of precursor and simple synthesis techniques have decisive roles in ...Carbon based nanomaterials are acknowledged for their admirable optical,electrical,mechanical characteristics and broad class of applications.Choice of precursor and simple synthesis techniques have decisive roles in viable production and commercialization of carbon produce.The intense demand to develop high purity carbon nanomaterials through inexpensive techniques has promoted usage of fossil derivatives as feasible source of carbon.Coal serves as a naturally available,abundant and cheap feedstock for carbon materials.From the crystalline clusters of aromatic hydrocarbons in a cross-linked network,carbon nanostructures can easily be extracted through green synthesis routes.It promotes a potent alternative for the cost effective and scaled up production of nanocarbon.The well-developed pores distribution,presence of numerous active sites and appropriate migration channels for ions enhance the electrochemical parameters necessary for the fabrication of supercapacitors,batteries and electrochemical sensors.The metallic impurities contained in coal contribute towards faradic redox reactions required for an efficient electrode modification.In this review,the potential uses of coal based carbon nanomaterials in energy storage and environmental sectors are discussed in detail.展开更多
Skin cancer has been recognized as one of the most lethal and complex types of cancer for over a decade.The diagnosis of skin cancer is of paramount importance,yet the process is intricate and challenging.The analysis...Skin cancer has been recognized as one of the most lethal and complex types of cancer for over a decade.The diagnosis of skin cancer is of paramount importance,yet the process is intricate and challenging.The analysis and modeling of human skin pose significant difficulties due to its asymmetrical nature,the visibility of dense hair,and the presence of various substitute characteristics.The texture of the epidermis is notably different from that of normal skin,and these differences are often evident in cases of unhealthy skin.As a consequence,the development of an effective method for monitoring skin cancer has seen little progress.Moreover,the task of diagnosing skin cancer from dermoscopic images is particularly challenging.It is crucial to diagnose skin cancer at an early stage,despite the high cost associated with the procedure,as it is an expensive process.Unfortunately,the advancement of diagnostic techniques for skin cancer has been limited.To address this issue,there is a need for a more accurate and efficient method for identifying and categorizing skin cancer cases.This involves the evaluation of specific characteristics to distinguish between benign and malignant skin cancer occurrences.We present and evaluate several techniques for segmentation,categorized into three main types:thresholding,edge-based,and region-based.These techniques are applied to a dataset of 200 benign and melanoma lesions from the Hospital Pedro Hispano(PH2)collection.The evaluation is based on twelve distinct metrics,which are designed to measure various types of errors with particular clinical significance.Additionally,we assess the effectiveness of these techniques independently for three different types of lesions:melanocytic nevi,atypical nevi,and melanomas.The first technique is capable of classifying lesions into two categories:atypical nevi and melanoma,achieving the highest accuracy score of 90.00%with the Otsu(3-level)method.The second technique also classifies lesions into two categories:common nevi and melanoma,achieving a score of 90.80%with the Binarized Sauvola method.展开更多
We propose to investigate the THz field generation using nonlinear mixing mechanism of laser beat wave with inclined rippled density plasmas.Two laser pulses with frequencies(ω_(1),ω_(2)) and wave vectors(k_(1),k_(2...We propose to investigate the THz field generation using nonlinear mixing mechanism of laser beat wave with inclined rippled density plasmas.Two laser pulses with frequencies(ω_(1),ω_(2)) and wave vectors(k_(1),k_(2)) co-propagate and resultant laser beat wave forms at beat frequency(ω_(1)-ω_(2)).Laser beat wave imparts a nonlinear force on the ambient electrons and pushes them outward with nonlinear velocity v_(NL).Coupling of induced density perturbation and nonlinear velocity v_(NL)generates nonlinear currents at laser beat frequency that further generates electromagnetic field E_((ω_(1)-ω_(2))) in terahertz(THz)range.In the present scheme,density ripples are introduced at an angle with respect to laser propagation and flat Gaussian index(f) is introduced in laser field profile that transform curved top of Gaussian field envelope into flat top field envelope.The combined effect of flat laser pulses with inclined density ripples in plasmas shows 10-fold enhancement in THz field amplitude when flat-Gaussian index(f) varies from 1 to 4.Also,the THz field intensifies when density ripples inclination increases upto a certain angle and then decreases.展开更多
Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway model.The acoustic phonons are considered to be the major carriers of heat ...Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway model.The acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon processes.Numerical calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering mechanisms.Our systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for T<~50 K,and suggests a value of 0.2 for the Gruneisen parameter.It is,however,found that for T>100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreement with the TC data over the wide temperature range.More detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal management devices.展开更多
The study of complex properties in a binary mixture of 1,2-dichloroethane(DE)and n-methylformamide(NMF)polar liquids has been carried out in the frequency range of 10 MHz to 30 GHz for 11 different concentrations usin...The study of complex properties in a binary mixture of 1,2-dichloroethane(DE)and n-methylformamide(NMF)polar liquids has been carried out in the frequency range of 10 MHz to 30 GHz for 11 different concentrations using time domain reflectometry technique at 283,288,293 and 298 K temperatures.Complex property of binary liquids indicates the type of distribution of the dielectric relaxation time.The Bruggeman parameter gives the information about molecular interactions within binary polar liquids.Thermodynamic parameter deals with the passing of a dipole across a potential barrier which separates the minima of energy.展开更多
The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined ...The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined using Time Domain Reflectometry(TDR)technique in the frequency range 10MHz to 50 GHz.The complex permittivity spectra for EGME-water were fitted in the Cole-Davidson model.The Static dielectric constant(ε_(0)^(E)),Relaxation time(τ),effective Kirkwood correlation factor(g_(eff)),excess permittivity(ε_(0)),thermodynamic parameters(activation enthalpy and activation entropy)and Bruggeman factor(f_(B))have been calculated by the nonlinear least square fit method.The intermolecular interactions between EGME-water binary mixtures suggest the nonlinear behavior of dielectric parameters.The contribution of hydrogen bonding interactions among the solute-solvent mixtures is confirmed by Excess properties and Bruggeman factor.展开更多
文摘A liquid phase chemical bath deposition(LPCBD)method for deposition of PbS thin films is presented.The growth kinetics and reaction mechanism have been discussed.For the deposition,triethanolamine complex of lead acetate was allowed to react with aqueous thiourea solution.Glass micro-slides were used as the substrates.The deposition of PbS films was carried out under different growth parameters such as temperature,time,and reaction pH.The growth rate,under different conditions,was measured in terms of a terminal layer thickness and the possible reaction kinetics and mechanism is discussed.The optimum values of the parameters to produce good quality films are 60 min,80℃and 10.5±0.1.An EDS analysis showed that the film stoichiometry is dependent on the reaction pH and the films tend to be almost stoichiometric in high alkaline environment(>10.5).The PbS deposits appeared smooth,tightly adherent,uniform and reflecting with blackish-grey colour.The XRD studies showed crystalline cubic type of structure with preferred orientation along(200)plane.The calculated d-values,intensities of reflections and lattice parameter have excellent match with that of the JCPD data.The crystallite size is found to be few tens of nanometer.The surface morphology revealed by SEM showed that the crystallites are randomly oriented and are of different shapes and sizes.Majority of the crystallites appeared smaller and spherical in shape whereas,growth of some elongated irregular crystallites;bit larger in size and differing in shapes,have also been favoured.
基金Department of Science and Technology,Ministry of Science and Technology(IF 180596).
文摘Carbon based nanomaterials are acknowledged for their admirable optical,electrical,mechanical characteristics and broad class of applications.Choice of precursor and simple synthesis techniques have decisive roles in viable production and commercialization of carbon produce.The intense demand to develop high purity carbon nanomaterials through inexpensive techniques has promoted usage of fossil derivatives as feasible source of carbon.Coal serves as a naturally available,abundant and cheap feedstock for carbon materials.From the crystalline clusters of aromatic hydrocarbons in a cross-linked network,carbon nanostructures can easily be extracted through green synthesis routes.It promotes a potent alternative for the cost effective and scaled up production of nanocarbon.The well-developed pores distribution,presence of numerous active sites and appropriate migration channels for ions enhance the electrochemical parameters necessary for the fabrication of supercapacitors,batteries and electrochemical sensors.The metallic impurities contained in coal contribute towards faradic redox reactions required for an efficient electrode modification.In this review,the potential uses of coal based carbon nanomaterials in energy storage and environmental sectors are discussed in detail.
文摘Skin cancer has been recognized as one of the most lethal and complex types of cancer for over a decade.The diagnosis of skin cancer is of paramount importance,yet the process is intricate and challenging.The analysis and modeling of human skin pose significant difficulties due to its asymmetrical nature,the visibility of dense hair,and the presence of various substitute characteristics.The texture of the epidermis is notably different from that of normal skin,and these differences are often evident in cases of unhealthy skin.As a consequence,the development of an effective method for monitoring skin cancer has seen little progress.Moreover,the task of diagnosing skin cancer from dermoscopic images is particularly challenging.It is crucial to diagnose skin cancer at an early stage,despite the high cost associated with the procedure,as it is an expensive process.Unfortunately,the advancement of diagnostic techniques for skin cancer has been limited.To address this issue,there is a need for a more accurate and efficient method for identifying and categorizing skin cancer cases.This involves the evaluation of specific characteristics to distinguish between benign and malignant skin cancer occurrences.We present and evaluate several techniques for segmentation,categorized into three main types:thresholding,edge-based,and region-based.These techniques are applied to a dataset of 200 benign and melanoma lesions from the Hospital Pedro Hispano(PH2)collection.The evaluation is based on twelve distinct metrics,which are designed to measure various types of errors with particular clinical significance.Additionally,we assess the effectiveness of these techniques independently for three different types of lesions:melanocytic nevi,atypical nevi,and melanomas.The first technique is capable of classifying lesions into two categories:atypical nevi and melanoma,achieving the highest accuracy score of 90.00%with the Otsu(3-level)method.The second technique also classifies lesions into two categories:common nevi and melanoma,achieving a score of 90.80%with the Binarized Sauvola method.
文摘We propose to investigate the THz field generation using nonlinear mixing mechanism of laser beat wave with inclined rippled density plasmas.Two laser pulses with frequencies(ω_(1),ω_(2)) and wave vectors(k_(1),k_(2)) co-propagate and resultant laser beat wave forms at beat frequency(ω_(1)-ω_(2)).Laser beat wave imparts a nonlinear force on the ambient electrons and pushes them outward with nonlinear velocity v_(NL).Coupling of induced density perturbation and nonlinear velocity v_(NL)generates nonlinear currents at laser beat frequency that further generates electromagnetic field E_((ω_(1)-ω_(2))) in terahertz(THz)range.In the present scheme,density ripples are introduced at an angle with respect to laser propagation and flat Gaussian index(f) is introduced in laser field profile that transform curved top of Gaussian field envelope into flat top field envelope.The combined effect of flat laser pulses with inclined density ripples in plasmas shows 10-fold enhancement in THz field amplitude when flat-Gaussian index(f) varies from 1 to 4.Also,the THz field intensifies when density ripples inclination increases upto a certain angle and then decreases.
基金supported by University Grants Commission(UGC),India。
文摘Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway model.The acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon processes.Numerical calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering mechanisms.Our systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for T<~50 K,and suggests a value of 0.2 for the Gruneisen parameter.It is,however,found that for T>100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreement with the TC data over the wide temperature range.More detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal management devices.
基金The department of Science and Technology,New Delhi is gratefully acknowledged(Project No.SR/S2/LOP-25/2007)for its laboratory facility.
文摘The study of complex properties in a binary mixture of 1,2-dichloroethane(DE)and n-methylformamide(NMF)polar liquids has been carried out in the frequency range of 10 MHz to 30 GHz for 11 different concentrations using time domain reflectometry technique at 283,288,293 and 298 K temperatures.Complex property of binary liquids indicates the type of distribution of the dielectric relaxation time.The Bruggeman parameter gives the information about molecular interactions within binary polar liquids.Thermodynamic parameter deals with the passing of a dipole across a potential barrier which separates the minima of energy.
基金This work was supported by the Department of Science and Technology,New Delhi(Project No.DST PROJECTSB/S2/LOP-032/2013)as well as School of Physical Sciences,SRTM University,Nanded,India for providing necessary facilities。
文摘The Complex permittivity spectra of glycol ether(GE)compounds such as ethylene glycol mono-methyl ether(EGME)with water mixture over entire concentration range and in temperature range of 10-25℃ have been determined using Time Domain Reflectometry(TDR)technique in the frequency range 10MHz to 50 GHz.The complex permittivity spectra for EGME-water were fitted in the Cole-Davidson model.The Static dielectric constant(ε_(0)^(E)),Relaxation time(τ),effective Kirkwood correlation factor(g_(eff)),excess permittivity(ε_(0)),thermodynamic parameters(activation enthalpy and activation entropy)and Bruggeman factor(f_(B))have been calculated by the nonlinear least square fit method.The intermolecular interactions between EGME-water binary mixtures suggest the nonlinear behavior of dielectric parameters.The contribution of hydrogen bonding interactions among the solute-solvent mixtures is confirmed by Excess properties and Bruggeman factor.
