The reflectivity of one-dimensional chalcogenide photonic crystal(CGPC) structure with the first order reflection band in near infrared(NIR) region is theoretically studied.Sb-Se and Ge-S chalcogenide glasses are used...The reflectivity of one-dimensional chalcogenide photonic crystal(CGPC) structure with the first order reflection band in near infrared(NIR) region is theoretically studied.Sb-Se and Ge-S chalcogenide glasses are used as high and low refractive index layers respectively,because these materials have zero absorption in NIR region.The transfer matrix method(TMM) is employed to calculate the reflective spectra of the proposed structure.The theoretical results of reflective spectra of bulk chalcogenide materials with the composition of Sb40Se60 and Ge30S70 for 4,8,12 and 15 layers and thicknesses of 117 nm and 183 nm respectively,at normal incidence,are close agreement with the experimental results.Furthermore,by increasing the number of layers of Sb40Se60 and Ge30S70,the reflection bands can be enhanced in the wider range of the NIR region for the polarization at different angles and thus the broadband omnidirectional reflector can be designed.展开更多
A key focus recently has been on assessing therisk of a coordinated cyber-physical attack and minimizing the impact of a successful attack. Most of the cyberattackers will have limited system information and conventio...A key focus recently has been on assessing therisk of a coordinated cyber-physical attack and minimizing the impact of a successful attack. Most of the cyberattackers will have limited system information and conventional power grid N-1 security analysis cannot be extended to assess the risk. Centrality measures are widely used in the network science and an attacker with incomplete information can use it to identify power system vulnerabilities by defining the system as a complex network but without real-time system measurements. This paper presents a graph theory based centrality indices for vulnerability assessment of the power system due to various bus and branch contingencies using limited system information and provides a preliminary defense mechanism to prevent such an attack. Proposed work answers the fundamental question of possible attack scenarios by balancing risk(limited information with low risk to get caught orhigh risk attack to access more system information) and impact(identifying contingencies with maximal impact on system operation). Statistical comparisons are made between the graph theory measures compared to the corresponding DC power flow based N-X linear sensitivity measures. A unified N-X centrality based performance index is proposed and validated against the AC power flow based performance index by doing the real-time simulations of an N-3 attack scenario. Defensive mechanisms using topology-based performance indices are also presented.展开更多
The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence nanocrystals.Using photo-induced alignment technique,the QRs can be oriented in...The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence nanocrystals.Using photo-induced alignment technique,the QRs can be oriented in liquid crystal polymer matrix at a large scale.In this article,a 2D Dammann grating pattern,within“SKL”characters domains aligned QRs in composite film,was fabricated by multi-step photo exposure using several photo masks,and a continuous geometric lens profile pattern aligned QRs was realized by the single step polarization converting holographic irradiation method.Both polarized optical microscope and fluorescence microscope are employed to determine the liquid crystal director profiles and QRs anisotropic excitation properties.We have been able to orient the QRs in fine binary and continuous patterns that confirms the strong quantum rod aligning ability of the proposed method.Thus,the proposed approach paves a way for photoinduced flexible QRs alignments to provide a highly specific and difficult-to-replicate security application at a large scale.展开更多
Dear Editor,The Coronavirus disease 2019(COVID-19)pandemic has caused over 670 million cases and 6.7 million deaths worldwide,many of which are attributed to cardiovascular complications.Virus-induced endothelial dama...Dear Editor,The Coronavirus disease 2019(COVID-19)pandemic has caused over 670 million cases and 6.7 million deaths worldwide,many of which are attributed to cardiovascular complications.Virus-induced endothelial damage,endothelial barrier dysfunction,thrombosis,and cytokine storm are implicated in heart and multi-organ failure.展开更多
This work presents the synthesis of Y_(2)O_(3):Eu^(3+),χCa^(2+)(χ=0 mol%,1 mol%,3 mol%,5 mol%,7 mol%,9 mol%,11 mol%)nanophosphors with enhanced photoluminescence properties through a facile solution combustion metho...This work presents the synthesis of Y_(2)O_(3):Eu^(3+),χCa^(2+)(χ=0 mol%,1 mol%,3 mol%,5 mol%,7 mol%,9 mol%,11 mol%)nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic,display,and lighting applications.The X-ray diffraction(XRD)patterns of the proposed nanophosphor reveal its structural properties and crystalline nature.The transmission electron microscope(TEM)results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca^(2+).Fourier transform infrared spectroscopy(FTIR)and Raman vibrations also confirm the presence of Y-O vibration and subsequently explain the crystalline nature,structural properties,and purity of the samples.All the synthesized nanophosphors samples emit intense red emission at 613 nm(~5D_(0)→~7 F_(2))under excitation with 235,394 and 466 nm wavelengths of Eu^(3+)ions.The photoluminescence(PL)emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength,respectively.The emission intensity of Y_(2)O_(3):Eu^(3+),χCa^(2+)(5 mol%)is increased 8-fold as compared to Eu:Y_(2)O_(3).Doping with Ca^(2+)ions enhances the emission intensity of Eu:Y_(2)O_(3)nanopho sphors due to an increase in energy transfer in Ca^(2+)→Eu^(3+)through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix.It is also observed that the optical band gap and the lifetime of the~5D_(0)level of Eu^(3+)ions in Y_(2)O_(3):Eu^(3+),xCa^(2+)nanophosphor sample gets changed with a doping conce ntration of Ca^(2+)ions.Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%,respectively.CIE,CCT,and color purity values(>98%)show an improved red-emitting nanophosphor in the warm region of light,which makes this mate rial superior with a speci展开更多
Unidirectionally aligned nanorods(NRs)are of great importance for different applications,including displays,lighting,and photodetectors.Recently,many alignment techniques were studied to align quantum rods(QRs).Howeve...Unidirectionally aligned nanorods(NRs)are of great importance for different applications,including displays,lighting,and photodetectors.Recently,many alignment techniques were studied to align quantum rods(QRs).However,the brightness of these films,due to the limited concentration of aligned quantum rods in the film,is not enough for their implementation as brightness enhancement films(BEFs)in displays.This can be ascribed to the poor miscibility of quantum rods in polymer and strong concentration dependence of the polarized emission.The ligands of NR are very important for the alignment and brightness.In this article,we proposed a ligand combination comprising T-shape promesogenic phosphonic acid,which on being photoaligned provides mutually parallel alignment of the quantum rods.The T-shape ligands enable the fabrication of hybrid films with a QRs concentration as high as 10 wt.%–20 wt.%retaining high brightness and luminescence polarization property.Later,we used these films in the in-plane switching(IPS)display backlight that shows the color gamut up to 121%of national television system committee(NTSC)(CIE1931),liquid-crystal display(LCD)efficiency up to 7.9%,power efficacy 103±2 nits/W,and the high brightness of~550±10 nits.Thus,the proposed ligands can be used for the alignment of a variety of nanorods.展开更多
Zinc oxide （ZnO） thin films were grown on silicon substrate by RF （radio frequency） magnetron sputtering.Surface topography of these films exhibited a nanostructured granular appearance with the size of individual...Zinc oxide （ZnO） thin films were grown on silicon substrate by RF （radio frequency） magnetron sputtering.Surface topography of these films exhibited a nanostructured granular appearance with the size of individual grains between 50 to 100 nm.Corresponding cross-sectional electron micrographs revealed columnar grains in the form of aggregated nanorods/wires with length of about 500 nm,similar to the thickness of these thin films of ZnO nucleated and grown vertically on the silicon substrate.High resolution lattice scale imaging using high resolution transmission electron microscope （HRTEM） elucidated the single crystalline 1010 planes of hexagonal-ZnO constituting the columnar grains with the individual nanorod diameter between 3 and 4 nm.The photoluminescence measurements showed the prominent emission peak at around 460 nm for the blue band,normally attributed to intrinsic defects in particular interstitial zinc （Zn）.These films were further characterized by X-ray diffraction （XRD）,Fourier transform infrared spectroscopy （FTIR）,Raman spectroscopy and electron paramagnetic resonance （EPR） to evaluate various aspects on preferred growth orientations,band structures and vibrational modes originated in such fascinating nano-grained thin films of ZnO.The present investigations inferred that these films are advantageous in various potential applications for fabricating nano-scaled devices.展开更多
We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network ana...We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network analyzer, Fourier transform infrared spectroscopy, a vibrating sample magnetometer and x-ray powder diffraction. Ba2Mg2Fe12O22 hexaferrite shows radiation loss of -37.25dB （99.999% loss） at frequency 9.81 GHz, which can be attributed to its high value of saturation magnetization, i.e., 22.08emu/g. Moreover, we obtain that magnetic properties have strong influence on the radiation losses.展开更多
Different kinds of soil animals and microorganisms inhabit the plant rhizosphere,which function closely to plant roots.Of them,arbuscular mycorrhizal fungi(AMF)and earthworms play a critical role in sustaining the soi...Different kinds of soil animals and microorganisms inhabit the plant rhizosphere,which function closely to plant roots.Of them,arbuscular mycorrhizal fungi(AMF)and earthworms play a critical role in sustaining the soilplant health.Earthworms and AMF belong to the soil community and are soil beneficial organisms at different trophic levels.Both of them improve soil fertility and structural development,collectively promoting plant growth and nutrient acquisition capacity.Earthworm activities redistribute mycorrhizal fungi spores and give diversified effects on root mycorrhizal fungal colonization.Dual inoculation with both earthworms and AMF strongly magnifies the response on plant growth through increased soil enzyme activities and changes in soil nutrient availability,collectively mitigating the negative effects of heavy metal pollution in plants and soils.This thus enhances phytoremediation and plant disease resistance.This review simply outlines the effects of earthworms and AMF on the soil-plant relationship.The effects of earthworms on root AMF colonization and activities are also analyzed.This paper also summarizes the interaction between earthworms and AMF on plants along with suggested future research.展开更多
We observed a C-class flare at the outer boundary of the superpenumbra of a sunspot. The flare was triggered by an emerging magnetic bipolar region that was obliquely oriented with respect to the superpenumbral fibril...We observed a C-class flare at the outer boundary of the superpenumbra of a sunspot. The flare was triggered by an emerging magnetic bipolar region that was obliquely oriented with respect to the superpenumbral fibrils. The flare started due to the low height magnetic reconnection of emerging magnetic flux with a superpenumbral field resulting in hot multi-temperature plasma flows in the inverse Evershed flow channel and its overlying atmosphere. Inverse Evershed flows in the chromosphere start from the superpenumbra towards the sunspot that end at the outer boundary of the penumbra. The hot plasma flow towards the sunspot in the inverse Evershed channels show about 10 km s^-1 higher velocity in Ha wavelengths compared to the plasma emissions at various temperatures as seen in different AIA filters. Even though these velocities are about seven times higher than the typical inverse Evershed flow speeds, the flow is diminished at the outer boundary of the sunspot＇s penumbra. This suggests that the superpenumbral field lines that carry inverse Evershed flows are discontinued at the boundary where the penumbral field lines dive into the sun and these two sets of field lines are completely distinct. The discontinuity in the typical magnetic field and plasma properties at the adjoining of these two sets of field lines further leads to discontinuity in the characteristic magnetoacoustic and Alfvrn speeds, thereby stopping the plasma flows further on. The multi-temperature plasma in the inverse Evershed channels exhibits possible longitudinal oscillations initially during the onset of the flare, and later flows towards the sunspot. In the multi-temperature view, the different layers above the flare region have a mixture of supersonic as well as subsonic flows.展开更多
The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as we...The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as well as Cretaceous mafic dykes;in展开更多
Light gray to yellowish brown youngest Toba tuff(YTT)ash,preserved in the Quaternary sediments of India,have been used as a tool to know depositional and bracketing time period of the same in the sediments through app...Light gray to yellowish brown youngest Toba tuff(YTT)ash,preserved in the Quaternary sediments of India,have been used as a tool to know depositional and bracketing time period of the same in the sediments through applications of luminescence dating to interpret age connotation of various geological events.Pre-and post-tephra sediments of YTT ash beds from Hudki and Sukali areas of Purna alluvial basin,Central India have been optically dated to interpret the depositional age and bracketing time of the tephra within sedimentary sequences.These sediments are yellowish brown,thinly bedded,laminated,silty clay and host laterally extend discontinued beds of 0.15–0.20 m thickness.The ash is light gray,fine grained and powdery in nature,massive to structureless and lacks any sign of retransportation and redeposition,hence,considered as primary in nature.Total four sediment samples,one each from pre-and post-tephra lithounits of both the localities have been dated through optically stimulated luminescence technique(OSL)equipped with single aliquot regenerative(SAR)procedure on the feldspar grains.It shows pre-and post-tephra ages of 57±5 and 70±4 ka respectively for Hudki and 66±5 and 67±4 ka for Sukali localities.These depositional ages suggest that the ash was bracketed within sediments thousands years after YTT eruption.It is correlatable with the previously reported depositional and absolute ages for the YTT ash from the localities of Ghoghara and Khuntheli,Son Valley;Tejpur,Madhumati River Basin and Jwalapuram,Jurreru Valley.These ages also provide an idea about the period of existence of biological communities represented by the remains of faunal and vegetational activities before and during settlement of the YTT ash in the basin area.展开更多
We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The ...We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, antitroponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI detection.The results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1 Hz,which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61(n = 0.61), whereas, it is 0.88(n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic(R_(et)) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL^(-1)–10.0 ng mL^(-1). The sensitivity of the transducer is 167.8 ± 14.2 Ω cm^2 per decade, and it also exhibits high specificity and good reproducibility.展开更多
Wastewaters from various process industries,namely food and agricultural,sugar mill,brewery,milk,vegetable and fruit,and meat and fsheries processing industries and their wastewater efuents contain nutrients,organic m...Wastewaters from various process industries,namely food and agricultural,sugar mill,brewery,milk,vegetable and fruit,and meat and fsheries processing industries and their wastewater efuents contain nutrients,organic matter,inorganic,heavy metals,suspended solids,and pathogens.The discharges of non-treated wastewater enter the nearby aquatic ecosystem(e.g.,lakes,rivers)and are a signifcant concern due to the presence of diferent nutrients,competing ions and C containing pollutants.It causes excessive growth of algae,loss of habitat/species,and other negative impacts on human health/environment.In the present review,diferent treatment approaches have been discussed in utilizing these nutrients to synthesize value-added products such as biopolymer,biofuel,pigment,organic acid,or enzymes.These biopolymers can be used to prepare various food products/packaging materials.Dextran,chitosan,carrageenan,alginate,and pectin are good examples of non-food biopolymers.Besides these products,poly-β-hydroxybutyrate(PHB)synthesis from wastewater nutrients is reported as a new source of bio-nanocomposite materials/biopolymer-based coatings.In this review,the diferent treatment approaches are discussed,which are being used worldwide for the removal/recovery of nutrients,toxic pollutants,and the potential resource recovery of value-added products from wastewater.展开更多
In this paper, a graphene-coated surface plasmon resonance sensor is designed for the examination of Rodent urine which is responsible for Leptospirosis bacteria. Rodent urine is considered as sensing medium. Graphene...In this paper, a graphene-coated surface plasmon resonance sensor is designed for the examination of Rodent urine which is responsible for Leptospirosis bacteria. Rodent urine is considered as sensing medium. Graphene surface is activated by phosphate-buffered saline solution for better attachment of Leptospirosis bacteria on its surface. Oliguria and Polyuria are the Rodent urine with high and low concentrations of Leptospirosis bacteria, respectively. The transfer matrix method is used for the formulation of reflection intensity of p-polarized light. The reflectance curves for angular interrogation are plotted and the results are obtained in terms of sensitivity, detection accuracy, and quality factor. The significantly high sensitivity and detection accuracy for Oliguria distinguishes it from Polyuria having lower sensitivity.展开更多
A precise dating of a mafic dyke of a swarm in shield areas has great advantage to identify Large Igneous Provinces(LIPs;short-lived,mantle-generated magmatic event)(Bryan and Ernst,2008;Ernst et al.,2010).Such
The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of
Objective:To perform a simultaneous quantitative estimation of two biologically active triterpenoid compounds lupeol and a steroid compound,stigmasterol,in Abutilon indicum(A.indicum)using high-performance thin-layer ...Objective:To perform a simultaneous quantitative estimation of two biologically active triterpenoid compounds lupeol and a steroid compound,stigmasterol,in Abutilon indicum(A.indicum)using high-performance thin-layer chromatography(HPTLC).Methods:TLC aluminum plates precoated with silica-gel 60 F254(20 cmí10 cm)were used with a mobile phase of toluene-methanol-formic acid(7.0:2.7:0.3,v/v/v)and densitometric determination of these compounds was carried out at 530 nm in reflectance/absorbance mode.Results:Compact bands for lupeol and stigmasterol were obtained at R_(f)0.52±0.02 and 0.28±0.05.The limit of detection(45 and 18 ng/band),limit of quantification(135 and 54 ng/band),recovery(98.2%-99.7%and 97.2%-99.6%)and precision(≤2.18 and 1.91)were satisfactory for lupeol and stigmasterol respectively.Linearity range for lupeol and stigmasterol were 100-1000(r^(2)=0.9994)and 50-500 ng/band(r^(2)=0.9941)and the contents were estimated as(0.59±0.10)%and(0.83±0.10)%w/w respectively.The total phenolic,flavonoid,proanthocyanidin,alkaloidal and saponin contents of methanolic extract of A.indicum were also measured in this work.According to International Conference on Harmonization(ICH)guidelines,the method was validated for linearity,precision,accuracy,and recovery,limit of detection,limit of quantification,specificity,and robustness.Conclusions:The HPTLC method was found to be reproducible,accurate,and precise and could detect these two compounds at nanogram level from the A.indicum.展开更多
文摘The reflectivity of one-dimensional chalcogenide photonic crystal(CGPC) structure with the first order reflection band in near infrared(NIR) region is theoretically studied.Sb-Se and Ge-S chalcogenide glasses are used as high and low refractive index layers respectively,because these materials have zero absorption in NIR region.The transfer matrix method(TMM) is employed to calculate the reflective spectra of the proposed structure.The theoretical results of reflective spectra of bulk chalcogenide materials with the composition of Sb40Se60 and Ge30S70 for 4,8,12 and 15 layers and thicknesses of 117 nm and 183 nm respectively,at normal incidence,are close agreement with the experimental results.Furthermore,by increasing the number of layers of Sb40Se60 and Ge30S70,the reflection bands can be enhanced in the wider range of the NIR region for the polarization at different angles and thus the broadband omnidirectional reflector can be designed.
文摘A key focus recently has been on assessing therisk of a coordinated cyber-physical attack and minimizing the impact of a successful attack. Most of the cyberattackers will have limited system information and conventional power grid N-1 security analysis cannot be extended to assess the risk. Centrality measures are widely used in the network science and an attacker with incomplete information can use it to identify power system vulnerabilities by defining the system as a complex network but without real-time system measurements. This paper presents a graph theory based centrality indices for vulnerability assessment of the power system due to various bus and branch contingencies using limited system information and provides a preliminary defense mechanism to prevent such an attack. Proposed work answers the fundamental question of possible attack scenarios by balancing risk(limited information with low risk to get caught orhigh risk attack to access more system information) and impact(identifying contingencies with maximal impact on system operation). Statistical comparisons are made between the graph theory measures compared to the corresponding DC power flow based N-X linear sensitivity measures. A unified N-X centrality based performance index is proposed and validated against the AC power flow based performance index by doing the real-time simulations of an N-3 attack scenario. Defensive mechanisms using topology-based performance indices are also presented.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)the National Natural Science Foundation of China(Nos.62005180,61935013)+2 种基金the Zhejiang Lab Open Research Project(No.K2022MG0AB01)RGC of Hong Kong S.A.R.(No.26202019)the State Key Laboratory of Advanced Displays and Optoelectronics Technologies(HKUST)(No.ITC-PSKL12EG02)。
文摘The anisotropic absorption and emission from semiconductor CdSe/CdS quantum rods(QRs)provide extra benefits among other photoluminescence nanocrystals.Using photo-induced alignment technique,the QRs can be oriented in liquid crystal polymer matrix at a large scale.In this article,a 2D Dammann grating pattern,within“SKL”characters domains aligned QRs in composite film,was fabricated by multi-step photo exposure using several photo masks,and a continuous geometric lens profile pattern aligned QRs was realized by the single step polarization converting holographic irradiation method.Both polarized optical microscope and fluorescence microscope are employed to determine the liquid crystal director profiles and QRs anisotropic excitation properties.We have been able to orient the QRs in fine binary and continuous patterns that confirms the strong quantum rod aligning ability of the proposed method.Thus,the proposed approach paves a way for photoinduced flexible QRs alignments to provide a highly specific and difficult-to-replicate security application at a large scale.
基金This work was supported by the British Heart Foundation(BHF)project grant“Targeting the SARS-CoV-2 S-protein binding to the ACE2 receptor to preserve human cardiac pericytes function in COVID-19”(PG/20/10285)(to P.M.and E.A.)European Commission H2020 CORDIS project COVIRNA(project/id/101016072)(to C.E.and P.K.S.)BHF Chair award(CH/15/1/31199)(to C.E).In addition,it was supported by a grant from the National Institute for Health Research(NIHR)Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol.E.A.is a postdoctoral researcher supported by the Heart Research UK translational project grant“Targeting pericytes for halting pulmonary hypertension in infants with congenital heart disease”(RG2697/21/23)(to P.M.and E.A.).I.B.is an investigator of the Wellcome Trust(106115/Z/14/Z).
文摘Dear Editor,The Coronavirus disease 2019(COVID-19)pandemic has caused over 670 million cases and 6.7 million deaths worldwide,many of which are attributed to cardiovascular complications.Virus-induced endothelial damage,endothelial barrier dysfunction,thrombosis,and cytokine storm are implicated in heart and multi-organ failure.
基金University Grants Commission(UGC),India for providing research fellowshipDST,New Delhi for fellowship under the Women Scientist Scheme-A with file number SR/WOS-A/CS-52/2018Institute of Eminence(IOE),Banaras Hindu University(BHU),India for financial support。
文摘This work presents the synthesis of Y_(2)O_(3):Eu^(3+),χCa^(2+)(χ=0 mol%,1 mol%,3 mol%,5 mol%,7 mol%,9 mol%,11 mol%)nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic,display,and lighting applications.The X-ray diffraction(XRD)patterns of the proposed nanophosphor reveal its structural properties and crystalline nature.The transmission electron microscope(TEM)results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca^(2+).Fourier transform infrared spectroscopy(FTIR)and Raman vibrations also confirm the presence of Y-O vibration and subsequently explain the crystalline nature,structural properties,and purity of the samples.All the synthesized nanophosphors samples emit intense red emission at 613 nm(~5D_(0)→~7 F_(2))under excitation with 235,394 and 466 nm wavelengths of Eu^(3+)ions.The photoluminescence(PL)emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength,respectively.The emission intensity of Y_(2)O_(3):Eu^(3+),χCa^(2+)(5 mol%)is increased 8-fold as compared to Eu:Y_(2)O_(3).Doping with Ca^(2+)ions enhances the emission intensity of Eu:Y_(2)O_(3)nanopho sphors due to an increase in energy transfer in Ca^(2+)→Eu^(3+)through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix.It is also observed that the optical band gap and the lifetime of the~5D_(0)level of Eu^(3+)ions in Y_(2)O_(3):Eu^(3+),xCa^(2+)nanophosphor sample gets changed with a doping conce ntration of Ca^(2+)ions.Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%,respectively.CIE,CCT,and color purity values(>98%)show an improved red-emitting nanophosphor in the warm region of light,which makes this mate rial superior with a speci
基金supported by the RGC of Hong Kong SAR,China(No.26202019)the funding for The State Key Laboratory of Advanced Displays and Optoelectronics Technologies.
文摘Unidirectionally aligned nanorods(NRs)are of great importance for different applications,including displays,lighting,and photodetectors.Recently,many alignment techniques were studied to align quantum rods(QRs).However,the brightness of these films,due to the limited concentration of aligned quantum rods in the film,is not enough for their implementation as brightness enhancement films(BEFs)in displays.This can be ascribed to the poor miscibility of quantum rods in polymer and strong concentration dependence of the polarized emission.The ligands of NR are very important for the alignment and brightness.In this article,we proposed a ligand combination comprising T-shape promesogenic phosphonic acid,which on being photoaligned provides mutually parallel alignment of the quantum rods.The T-shape ligands enable the fabrication of hybrid films with a QRs concentration as high as 10 wt.%–20 wt.%retaining high brightness and luminescence polarization property.Later,we used these films in the in-plane switching(IPS)display backlight that shows the color gamut up to 121%of national television system committee(NTSC)(CIE1931),liquid-crystal display(LCD)efficiency up to 7.9%,power efficacy 103±2 nits/W,and the high brightness of~550±10 nits.Thus,the proposed ligands can be used for the alignment of a variety of nanorods.
文摘Zinc oxide （ZnO） thin films were grown on silicon substrate by RF （radio frequency） magnetron sputtering.Surface topography of these films exhibited a nanostructured granular appearance with the size of individual grains between 50 to 100 nm.Corresponding cross-sectional electron micrographs revealed columnar grains in the form of aggregated nanorods/wires with length of about 500 nm,similar to the thickness of these thin films of ZnO nucleated and grown vertically on the silicon substrate.High resolution lattice scale imaging using high resolution transmission electron microscope （HRTEM） elucidated the single crystalline 1010 planes of hexagonal-ZnO constituting the columnar grains with the individual nanorod diameter between 3 and 4 nm.The photoluminescence measurements showed the prominent emission peak at around 460 nm for the blue band,normally attributed to intrinsic defects in particular interstitial zinc （Zn）.These films were further characterized by X-ray diffraction （XRD）,Fourier transform infrared spectroscopy （FTIR）,Raman spectroscopy and electron paramagnetic resonance （EPR） to evaluate various aspects on preferred growth orientations,band structures and vibrational modes originated in such fascinating nano-grained thin films of ZnO.The present investigations inferred that these films are advantageous in various potential applications for fabricating nano-scaled devices.
文摘We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network analyzer, Fourier transform infrared spectroscopy, a vibrating sample magnetometer and x-ray powder diffraction. Ba2Mg2Fe12O22 hexaferrite shows radiation loss of -37.25dB （99.999% loss） at frequency 9.81 GHz, which can be attributed to its high value of saturation magnetization, i.e., 22.08emu/g. Moreover, we obtain that magnetic properties have strong influence on the radiation losses.
基金This work was supported by the Plan in Scientific and Technological Innovation Team of Outstanding Young Scientists,Hubei Provincial Department of Education(T201604)the Hubei Agricultural Science and Technology Innovation Action Project(Hubei Nongfa[2018]No.1)the UHK Project VT2019-2021.
文摘Different kinds of soil animals and microorganisms inhabit the plant rhizosphere,which function closely to plant roots.Of them,arbuscular mycorrhizal fungi(AMF)and earthworms play a critical role in sustaining the soilplant health.Earthworms and AMF belong to the soil community and are soil beneficial organisms at different trophic levels.Both of them improve soil fertility and structural development,collectively promoting plant growth and nutrient acquisition capacity.Earthworm activities redistribute mycorrhizal fungi spores and give diversified effects on root mycorrhizal fungal colonization.Dual inoculation with both earthworms and AMF strongly magnifies the response on plant growth through increased soil enzyme activities and changes in soil nutrient availability,collectively mitigating the negative effects of heavy metal pollution in plants and soils.This thus enhances phytoremediation and plant disease resistance.This review simply outlines the effects of earthworms and AMF on the soil-plant relationship.The effects of earthworms on root AMF colonization and activities are also analyzed.This paper also summarizes the interaction between earthworms and AMF on plants along with suggested future research.
基金the Chinese Academy of Sciences to NAOCfunded by the Chinese Academy of Science President’s International Fellowship Initiative
文摘We observed a C-class flare at the outer boundary of the superpenumbra of a sunspot. The flare was triggered by an emerging magnetic bipolar region that was obliquely oriented with respect to the superpenumbral fibrils. The flare started due to the low height magnetic reconnection of emerging magnetic flux with a superpenumbral field resulting in hot multi-temperature plasma flows in the inverse Evershed flow channel and its overlying atmosphere. Inverse Evershed flows in the chromosphere start from the superpenumbra towards the sunspot that end at the outer boundary of the penumbra. The hot plasma flow towards the sunspot in the inverse Evershed channels show about 10 km s^-1 higher velocity in Ha wavelengths compared to the plasma emissions at various temperatures as seen in different AIA filters. Even though these velocities are about seven times higher than the typical inverse Evershed flow speeds, the flow is diminished at the outer boundary of the sunspot＇s penumbra. This suggests that the superpenumbral field lines that carry inverse Evershed flows are discontinued at the boundary where the penumbral field lines dive into the sun and these two sets of field lines are completely distinct. The discontinuity in the typical magnetic field and plasma properties at the adjoining of these two sets of field lines further leads to discontinuity in the characteristic magnetoacoustic and Alfvrn speeds, thereby stopping the plasma flows further on. The multi-temperature plasma in the inverse Evershed channels exhibits possible longitudinal oscillations initially during the onset of the flare, and later flows towards the sunspot. In the multi-temperature view, the different layers above the flare region have a mixture of supersonic as well as subsonic flows.
文摘The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as well as Cretaceous mafic dykes;in
基金financially supported by Science and Engineering Research Board(SERB),New Delhi,India in the form of major research project(No.SB/S4/ES-692/2013)awarded to AKS。
文摘Light gray to yellowish brown youngest Toba tuff(YTT)ash,preserved in the Quaternary sediments of India,have been used as a tool to know depositional and bracketing time period of the same in the sediments through applications of luminescence dating to interpret age connotation of various geological events.Pre-and post-tephra sediments of YTT ash beds from Hudki and Sukali areas of Purna alluvial basin,Central India have been optically dated to interpret the depositional age and bracketing time of the tephra within sedimentary sequences.These sediments are yellowish brown,thinly bedded,laminated,silty clay and host laterally extend discontinued beds of 0.15–0.20 m thickness.The ash is light gray,fine grained and powdery in nature,massive to structureless and lacks any sign of retransportation and redeposition,hence,considered as primary in nature.Total four sediment samples,one each from pre-and post-tephra lithounits of both the localities have been dated through optically stimulated luminescence technique(OSL)equipped with single aliquot regenerative(SAR)procedure on the feldspar grains.It shows pre-and post-tephra ages of 57±5 and 70±4 ka respectively for Hudki and 66±5 and 67±4 ka for Sukali localities.These depositional ages suggest that the ash was bracketed within sediments thousands years after YTT eruption.It is correlatable with the previously reported depositional and absolute ages for the YTT ash from the localities of Ghoghara and Khuntheli,Son Valley;Tejpur,Madhumati River Basin and Jwalapuram,Jurreru Valley.These ages also provide an idea about the period of existence of biological communities represented by the remains of faunal and vegetational activities before and during settlement of the YTT ash in the basin area.
文摘We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen(cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, antitroponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI detection.The results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1 Hz,which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61(n = 0.61), whereas, it is 0.88(n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic(R_(et)) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL^(-1)–10.0 ng mL^(-1). The sensitivity of the transducer is 167.8 ± 14.2 Ω cm^2 per decade, and it also exhibits high specificity and good reproducibility.
文摘Wastewaters from various process industries,namely food and agricultural,sugar mill,brewery,milk,vegetable and fruit,and meat and fsheries processing industries and their wastewater efuents contain nutrients,organic matter,inorganic,heavy metals,suspended solids,and pathogens.The discharges of non-treated wastewater enter the nearby aquatic ecosystem(e.g.,lakes,rivers)and are a signifcant concern due to the presence of diferent nutrients,competing ions and C containing pollutants.It causes excessive growth of algae,loss of habitat/species,and other negative impacts on human health/environment.In the present review,diferent treatment approaches have been discussed in utilizing these nutrients to synthesize value-added products such as biopolymer,biofuel,pigment,organic acid,or enzymes.These biopolymers can be used to prepare various food products/packaging materials.Dextran,chitosan,carrageenan,alginate,and pectin are good examples of non-food biopolymers.Besides these products,poly-β-hydroxybutyrate(PHB)synthesis from wastewater nutrients is reported as a new source of bio-nanocomposite materials/biopolymer-based coatings.In this review,the diferent treatment approaches are discussed,which are being used worldwide for the removal/recovery of nutrients,toxic pollutants,and the potential resource recovery of value-added products from wastewater.
基金Surjeet Raikwar is thankful to Dr.Abdul Kalam Technical University,Lucknow(India)for providing Research Grant Homi Bhabha Teaching Assistant Fellowship.
文摘In this paper, a graphene-coated surface plasmon resonance sensor is designed for the examination of Rodent urine which is responsible for Leptospirosis bacteria. Rodent urine is considered as sensing medium. Graphene surface is activated by phosphate-buffered saline solution for better attachment of Leptospirosis bacteria on its surface. Oliguria and Polyuria are the Rodent urine with high and low concentrations of Leptospirosis bacteria, respectively. The transfer matrix method is used for the formulation of reflection intensity of p-polarized light. The reflectance curves for angular interrogation are plotted and the results are obtained in terms of sensitivity, detection accuracy, and quality factor. The significantly high sensitivity and detection accuracy for Oliguria distinguishes it from Polyuria having lower sensitivity.
文摘A precise dating of a mafic dyke of a swarm in shield areas has great advantage to identify Large Igneous Provinces(LIPs;short-lived,mantle-generated magmatic event)(Bryan and Ernst,2008;Ernst et al.,2010).Such
文摘The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of
文摘Objective:To perform a simultaneous quantitative estimation of two biologically active triterpenoid compounds lupeol and a steroid compound,stigmasterol,in Abutilon indicum(A.indicum)using high-performance thin-layer chromatography(HPTLC).Methods:TLC aluminum plates precoated with silica-gel 60 F254(20 cmí10 cm)were used with a mobile phase of toluene-methanol-formic acid(7.0:2.7:0.3,v/v/v)and densitometric determination of these compounds was carried out at 530 nm in reflectance/absorbance mode.Results:Compact bands for lupeol and stigmasterol were obtained at R_(f)0.52±0.02 and 0.28±0.05.The limit of detection(45 and 18 ng/band),limit of quantification(135 and 54 ng/band),recovery(98.2%-99.7%and 97.2%-99.6%)and precision(≤2.18 and 1.91)were satisfactory for lupeol and stigmasterol respectively.Linearity range for lupeol and stigmasterol were 100-1000(r^(2)=0.9994)and 50-500 ng/band(r^(2)=0.9941)and the contents were estimated as(0.59±0.10)%and(0.83±0.10)%w/w respectively.The total phenolic,flavonoid,proanthocyanidin,alkaloidal and saponin contents of methanolic extract of A.indicum were also measured in this work.According to International Conference on Harmonization(ICH)guidelines,the method was validated for linearity,precision,accuracy,and recovery,limit of detection,limit of quantification,specificity,and robustness.Conclusions:The HPTLC method was found to be reproducible,accurate,and precise and could detect these two compounds at nanogram level from the A.indicum.
