This study presents the intercomparison of the outdoor environmental gamma dose rates measured using a Nal （TI） based survey meter along with thermoluminescent dosimeters （TLDs） and estimation of excess lifetime c...This study presents the intercomparison of the outdoor environmental gamma dose rates measured using a Nal （TI） based survey meter along with thermoluminescent dosimeters （TLDs） and estimation of excess lifetime cancer risk （ELCR）, for the inhabitants of Poonch division of the Azad Kashmir, Pakistan. CaF2： Dy （TLD-200） card dosimeters were installed at height of 1 m from ground at fifteen different locations covering the entire Poonch division comprising of three districts.展开更多
High-entropy alloys(HEAs)have emerged as promising catalysts for the hydrogen evolution reaction(HER)due to their compositional diversity and synergistic effects.In this study,machine learning-accelerated density func...High-entropy alloys(HEAs)have emerged as promising catalysts for the hydrogen evolution reaction(HER)due to their compositional diversity and synergistic effects.In this study,machine learning-accelerated density functional theory(DFT)calculations were employed to assess the catalytic performance of PtPd-based HEAs with the formula PtPdXYZ(X,Y,Z=Fe,Co,Ni,Cu,Ru,Rh,Ag,Au;X≠Y≠Z).Among 56 screened HEA(111)surfaces,PtPdRuCoNi(111)was identified as the most promising,with adsorption energies(E_(ads))between−0.50 and−0.60 eV and high d-band center of−1.85 eV,indicating enhanced activity.This surface showed the hydrogen adsorption free energy(ΔG_(H^(*)))of−0.03 eV for hydrogen adsorption,outperforming Pt(111)by achieving a better balance between adsorption and desorption.Machine learning models,particularly extreme gradient boosting regression(XGBR),significantly reduced computational costs while maintaining high accuracy(root-mean-square error,RMSE=0.128 eV).These results demonstrate the potential of HEAs for efficient and sustainable hydrogen production.展开更多
The present work reports the structural,optical,dielectric,and electrical properties of Eu-Er substituted M-type Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)(x=0.0.05,0.1,0.15,and 0.2)hexaferrites synthesized by sol-g...The present work reports the structural,optical,dielectric,and electrical properties of Eu-Er substituted M-type Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)(x=0.0.05,0.1,0.15,and 0.2)hexaferrites synthesized by sol-gel combustion method.The hexagonal structure of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples was confirmed from X-ray diffraction(XRD)analysis.The values of lattice parameters of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)samples are increased as compared to Ba_(0.5)Sr_(0.5)Fe_(12)O_(19) sample.This increase in the value of lattice parameters is attributed to the substitution of larger cations(Eu^(3+)and Er^(3+))in place of smaller cations(Fe^(3+)ions).The crystallite sizes of the Ba0.5Sr0.5EuxErxFe12-2x019 samples also increase due to the substitution of larger cations.The force constants(K_o and K_t)increases with increasing Eu-Er concentration.The octahedral cluster shifts towards the higher wavenumber side whereas the tetrahedral cluster shifts towards the lower wavenumber side due to Eu-Er substitution in the Fourier transform infrared(FTIR)spectra.The photoluminescence(PL)emission spectra for the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples are observed at 365 nm.The dielectric dispersion in the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples can be understood by Koop's theory and Maxwell-Wagner type of inte rfacial polarization.Using Jonscher's power law and the co rrelated barrier hopping(CBH)model,the frequency and temperature-dependent be haviour of ac conductivity of Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples are described.The temperature-dependent behaviour of the dc conductivity of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples is explained by the variable range hopping(VRH)model.The Motto temperature of the sample varies from 4.55×10^(9) to 2.31×10^(8) K.The estimated maximum barrier height(WM)of the compound varies from 0.6603 to 0.1199 eV.The temperature coefficient and activation energy of the samples were also calculated as a function of Eu-Er concentration.展开更多
Dose estimation and quality control in computed tomography (CT) scanners are useful in controlling the dose of radiation given to patients while tests are carried out. The study was performed in a 16-slice Computed To...Dose estimation and quality control in computed tomography (CT) scanners are useful in controlling the dose of radiation given to patients while tests are carried out. The study was performed in a 16-slice Computed Tomography (CT) system of LightSpeed RT16 Xtra CT scanner. Quality control was done using a vendor-provided QA Phantom, and the six aspects of image quality were measured. For CT dosimetry, Computed Tomography Dose index volume (CTDIvol) was performed using Computed Tomography Dose Index (CTDI) Phantom. CTDI Phantom consists of three parts: Pediatric Head, Adult Head, and Adult Body Phantom. A 10 cm long pencil ion chamber DCT-10 was used to measure the dose at different positions inside the CTDI Phantom. Data were collected using MagicMax Universal software. For dose estimation of the CTDIvol Report of AAPM Task Group, 96 and 111 formalisms were used. For Pediatric Head, Adult Head, and Adult Body Phantom the measured CIDIvol was 61.04 mGy, 48.11 mGy, and 18.08 mGy respectively. The study has shown deviations of 7%, 15%, and 19% between estimated and console-displayed doses for Pediatric Head, Adult Head, and Adult Body scan techniques respectively. The six aspects of image quality measured by QA Phantom were found to be compatible with the specifications of the machine and CTDIvol measured by CTDI Phantom were found within a tolerance limit of ±20%. Hence, the QC and dosimetry of the mentioned machine are within the limit.展开更多
MgATP is a stable complex formed by the chelation of Mg^(2+)with deprotonated adenosine-5'-triphosphate(ATP).In the cellular environment,MgATP plays a critical role in ATP hydrolysis,releasing substantial energy t...MgATP is a stable complex formed by the chelation of Mg^(2+)with deprotonated adenosine-5'-triphosphate(ATP).In the cellular environment,MgATP plays a critical role in ATP hydrolysis,releasing substantial energy to support essential biological functions.To understand the structure and stabilization mechanism of MgATP,we conducted a joint negative ion photoelectron spectroscopic and computational study of the[ATP^(4-)·Mg^(2+)]^(2-)complex dianion,using[ATP^(4-)·2H^(+)]^(2-)as a reference.The experimentally determined adiabatic and vertical detachment energies(ADE and VDE)of[ATP^(4-)·Mg^(2+)]^(2-)at 20 K are 3.51±0.05 eV and 3.82±0.05 eV,respectively.The major spectral features of[ATP^(4-)·Mg^(2+)]^(2-)are attributed to two theoretically identified isomers with unfolded geometries,which are stabilized primarily by electrostatic interactions between Mg^(2+)and the triphosphate and ribose groups,with four deprotonated oxygens forming a pseudo-tetrahedral coordination.In contrast,[ATP^(4-)·2H^(+)]^(2-)exhibits a fundamentally different stabilization mechanism.Although most of the fifteen identified[ATP^(4-)·2H^(+)]^(2-)isomers also adopt unfolded geometries,they are primarily stabilized by intramolecular hydrogen bonds within the triphosphate group and between triphosphate and ribose groups.The interaction between ATP^(4-)and two protons is found to be much weaker than that with Mg^(2+),and[ATP^(4-)·2H^(+)]^(2-)exhibits substantial structural flexibility compared to[ATP^(4-)·Mg^(2+)]^(2-)due to the conformational constraint of the triphosphate chain by Mg^(2+).Thirteen[ATP^(4-)·2H^(+)]^(2-)isomers with unfolded geometries likely account for the major high-EBE(electron-binding-energy)spectral features.Notably,for the first time,a low EBE and temperature-dependent spectral feature is observed and attributed to two folded isomers of[ATP^(4-)·2H^(+)]^(2-),which exist at 20 K but disappear at room temperature.This study provides valuable molecular-level insights into cellular MgATP that resides within the hydrophobic pockets of proteins.展开更多
Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that...Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that IP exhibits sudden change, and one side quantum channel is enough for the occurrence of a sudden change of IP. In particular, we show that the initial state having no sudden change of quantum discord exhibits a sudden change of IP under the dynamics of amplitude noise, but the converse is not true. Besides, we also investigate the dynamics of IP under two different kinds of composite noises. Our results also confirm that sudden change of IP occurs under such composite noises.展开更多
Perovskite oxides have shown great potential application in fuel cells due to the unique crystal structures and tunable composition as well as effective capability toward the oxygen reduction reaction(ORR),whereas the...Perovskite oxides have shown great potential application in fuel cells due to the unique crystal structures and tunable composition as well as effective capability toward the oxygen reduction reaction(ORR),whereas the investigation on the electrocatalytic performance of perovskite oxides toward the two-electron ORR to H_(2)O_(2)production remains very limited.Herein,a facile synthetic method has been developed to prepare La_(2)Sn_(2)O_(7)@La-doped ZnSnO_(3)heterostructures comprising of amorphous La_(2)Sn_(2)O_(7)and crystalline La-doped ZnSnO_(3).The optimal La_(2)Sn_(2)O_(7)@Ladoped ZnSnO_(3)heterostructures catalyst exhibits a significantly improved two-electron ORR performance to H_(2)O_(2)production with onset potential of 0.77 V and large current density of 2.51 m A.cm^(-2)at 0.1 V compared to ZnSnO_(3)(0.75 V,1.80 m A.cm^(-2),0.11 m A) as well as maintains high H_(2)O_(2)selectivity of 80%,which has been theoretically demonstrated to be contributed to the synergistic effect of amorphous La_(2)Sn_(2)O_(7)and crystalline La-doped ZnSnO_(3).Moreover,high H_(2)O_(2)yield rate of 2.9 m M.h^(-1)at 0.1 V can be achieved with a superior turnover frequency(TOF) of3.31 × 10^(-2)s^(-1)compared to the ZnSnO_(3)catalyst(2.10 × 10^(-2)s^(-1)).This work reveals the great potential of perovskite oxide as promising candidates for the environmentally friendly synthesis of hydrogen peroxide.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic com...Graphitic carbon nitride(g-C_(3)N_(4))exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds,an electrolyte for fuel cell applications or power sources,and a hydrogen storage substance and a fluorescence detector.It is fabricated using dif-ferent methods,and there is a variety of morphologies and nanostructures such as zero to three dimensions that have been designed for different purposes.Ther e are many reports about g-C_(3)N_(4) in recent years,but a comprehensive review which covers nanostructure dimensions and their properties are missing.This review paper aims to give basic and comprehensive understanding of the photocatalytic and electrocatalytic usages of g-C_(3)N_(4).It highlights the recent progress of g-C_(3)N_(4) nano-structure designing by covering synthesis methods,dimensions,morphologies,applications and properties.Along with the summary,we will also discuss the challenges and prospects.Scientists,investigators,and engineers looking at g-C_(3)N_(4) nanostructures for a variety of applications might find our review paper to be a useful resource.展开更多
Strategic design and synergistic interactions between the electrodes and electroactive materials profoundly influence the energy storage efficiency of supercapacitor devices. Herein, we present the interfacial enginee...Strategic design and synergistic interactions between the electrodes and electroactive materials profoundly influence the energy storage efficiency of supercapacitor devices. Herein, we present the interfacial engineering of CoMoS_(4)-NiS_(2) with a well-defined construction of amorphous/crystalline hetero-phases deposited on carbon cloth using a hydrothermal technique. The optimal in-situ growth of CoMoS_(4)-NiS_(2)@CFC boasts an impressive areal capacity of 1341 mC cm^(-2) and retains ∼91 % capacity after 5000 cycles, attributed to the synergy effect and improved conductivity of multi-metallic sulfide ions over the CFC substrate. Density functional theory (DFT) reveals the metallic nature of CoMoS_(4)-NiS_(2)@CFC and favorable OH- ion adsorption energy of -4.35 eV, enhancing its charge storage capabilities. Furthermore, a hybrid supercapacitor (HSC) and Pouch HSC are assembled utilizing the CoMoS_(4)-NiS_(2)@CFC as a positrode and marine waste jellyfish-derived AC as a negatrode with an aqueous electrolyte. The HSC and PHSC demonstrate superior specific energies of 51.99 and 58.4 W h kg^(-1), respectively, along with corresponding specific powers of 800 and 780 W kg^(-1), maintaining robust stability of ∼90 % stability over 10000 cycles. Additionally, the HSC and PHSC have successfully illuminated several light-emitting diodes (LEDs) demonstrating superior energy storage performance. This work advances the design of hetero-phase multi-metal sulfides, paving the way for high-performance supercapacitor devices.展开更多
The^(6)Li+^(89)Y experiment was performed to explore the reaction mechanism induced by a weakly bound nucleus^(6)Li and its cluster configuration.The particle-γcoincidence method was used to identify the different re...The^(6)Li+^(89)Y experiment was performed to explore the reaction mechanism induced by a weakly bound nucleus^(6)Li and its cluster configuration.The particle-γcoincidence method was used to identify the different reaction channels.Theγ-rays coincident with^(3)He/^(3)H indicate that the^(3)H/^(3)He stripping reaction plays a significant role in the formation of Zr/Nb isotopes.The obtained results support the existence of a^(3)He-^(3)H cluster in^(6)Li.Direct and sequential transfer reactions are adequately discussed,and the FRESCO code is used to perform precise finite-range cyclic redundancy check calculations.In the microscopic calculation,direct cluster transfer is more predominant than sequential transfer in^(3)H transfer.However,the direct cluster transfer is of comparable magnitude to the sequential transfer in the^(3)He transfer.展开更多
The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life....The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life.Polyurethane(PU)-based materials have gained attention as promising candidates for supercapacitor electrodes,due to their flexibility,mechanical robustness,and tunable properties.It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms.Instead,PU serves as a flexible scaffold,a binder,or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment.Thus,the term'PU-based'in this review refers to PU-supported or PU-derived composites,where PU enables structural or functional integration of active electrode Materi-als.Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm^(2)with capacitance retention of 92%over 5,000 cycles.Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg,reflecting their potential for high-performance energy storage applications.Despite these advantages,challenges,such as low intrinsic conductivity and the environmental impact of traditional synthesis methods,limit their widespread adoption.Conventional PU composites often incorporate conductive additives like carbon materi-als,metal oxides,or conductive polymers to enhance their electrochemical performance,yet these approaches may involve non-renewable or toxic components.Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations.This includes using renewable resources,environmentally friendly process-ing techniques,and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies.This review highlights current trends in developing eco-friendly supercapacitor materials,addressing key challenges such as limited conductivity and complex processing.It uniquely integrates green chemistry principles with advances in polyurethane composites,emphasizing sustainable feedstocks,heteroatom doping,and functional nanomateri-als.By combining these aspects,this review provides a comprehensive perspective not fully covered in existing literature.展开更多
Mossbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L （1.4306S）, Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690, at ...Mossbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L （1.4306S）, Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690, at 1200℃ exposed in air and steam environments for 400 h. The basic aim was to identify and compare the iron oxides qualitatively and quantitatively, formed during the oxidation of these alloys in two environments. The behaviour of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam, whereas Sanicro-28 has excellent corrosion resistance in steam environment. In air oxidation of Inconel-690 no iron oxide, with established Mossbauer parameters, was detected.展开更多
Poly(p-phenylenediamine)/chitosan (PPPDA/Chi) composite was prepared by in situ chemical oxidative polymerization of p-phenylenediamine (PPPDA) into chitosan (Chi) using ammonium persulphate (APS) as an oxidant. PPPDA...Poly(p-phenylenediamine)/chitosan (PPPDA/Chi) composite was prepared by in situ chemical oxidative polymerization of p-phenylenediamine (PPPDA) into chitosan (Chi) using ammonium persulphate (APS) as an oxidant. PPPDA and PPPDA/Chi composite were characterized by FT-IR spectra and SEM before and after copper loading. In batch adsorption method, the maximum removal of copper was experienced when 1 g/L of PPPDA and PPPDA/Chi composite dosages were used at pH 5.0 for PPPDA and 6.0 for PPPDA/Chi composite for 360 min for both sorbents. PPPDA showed adsorption capacity q<sub>e</sub><sup>max</sup> of 650 mg/g whereas its composite achieved q<sub>e</sub><sup>max</sup> of 573 mg/g. The experimental data correlate well with the Freundlich isotherm equation and the pseudo-second order kinetic model. The Cu(II), loaded PPPDA and its composite can be efficiently reused for as many as four cycles. The Cu(II)-loaded sorbents showed high antibacterial efficiency against Gram-positive and Gram-negative bacteria than their unloaded forms.展开更多
We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation o...We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation of ethylbenzene activities was measured in a round bottom flask immersed in oil bath at known reaction temperature. The physicochemical characteristics of the catalysts were examined by BET surface area, XRD, FT-IR and the oxidation activities were correlated with the acidities of the catalysts obtained by TPD of NH3. It was observed that both hydroxyapatite and USY （13% Na2O） supported Ni catalysts displayed higher ethylbenzene conversion and 80% selectivity towards acetophenone.展开更多
Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and tr...Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEM） and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.展开更多
Porous silica prepared by using an acrylic emulsion has been impregnated with bismuth ion resulting in Bi2Si05 species containing surface. The as-prepared materials have been characterized by X-ray diffraction spectro...Porous silica prepared by using an acrylic emulsion has been impregnated with bismuth ion resulting in Bi2Si05 species containing surface. The as-prepared materials have been characterized by X-ray diffraction spectroscopy （XRD）, X-ray photoelectron spectroscopy （XPS）, UV-Vis diffuse reflectance spectroscopy （UV-Vis DRS）, scanning electron microscopy （SEM）, energy dispersive analysis of X-ray （EDAX）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR） and N2 adsorption/desorption techniques. EDAX analysis confirms the penetration of bismuth ions into the framework of silica to form Bi2SiO5, which is substantiated by XRD. The UV-Vis DRS shows that the catalysts are optically active and XPS confirms the inclusion of bismuth into the framework of silica. FTIR spectra illustrate the formation of Bi-O-Si linkages in the porous silica framework. SEM and TEM show the spherical morphology, whereas N2 adsorption/desorption study confirms the porosity of the prepared materials. The photocatalytic activity of the material is evaluated for the degradation of isoproturon herbicide and it is found that the material is active as compared to the commercial P-25 Degussa TiO2.展开更多
文摘This study presents the intercomparison of the outdoor environmental gamma dose rates measured using a Nal （TI） based survey meter along with thermoluminescent dosimeters （TLDs） and estimation of excess lifetime cancer risk （ELCR）, for the inhabitants of Poonch division of the Azad Kashmir, Pakistan. CaF2： Dy （TLD-200） card dosimeters were installed at height of 1 m from ground at fifteen different locations covering the entire Poonch division comprising of three districts.
基金the Second Century Fund(C2F),Chulalongkorn UniversityThailand Science Research and Innovation Fund Chulalongkorn University(No.IND_FF_68_054_2100_009)National Science and Technology Development Agency,Thailand,Hub of Knowledge funding,and the Mid-Career Research Grant 2024,National Research Council of Thailand(No.N42A670295).
文摘High-entropy alloys(HEAs)have emerged as promising catalysts for the hydrogen evolution reaction(HER)due to their compositional diversity and synergistic effects.In this study,machine learning-accelerated density functional theory(DFT)calculations were employed to assess the catalytic performance of PtPd-based HEAs with the formula PtPdXYZ(X,Y,Z=Fe,Co,Ni,Cu,Ru,Rh,Ag,Au;X≠Y≠Z).Among 56 screened HEA(111)surfaces,PtPdRuCoNi(111)was identified as the most promising,with adsorption energies(E_(ads))between−0.50 and−0.60 eV and high d-band center of−1.85 eV,indicating enhanced activity.This surface showed the hydrogen adsorption free energy(ΔG_(H^(*)))of−0.03 eV for hydrogen adsorption,outperforming Pt(111)by achieving a better balance between adsorption and desorption.Machine learning models,particularly extreme gradient boosting regression(XGBR),significantly reduced computational costs while maintaining high accuracy(root-mean-square error,RMSE=0.128 eV).These results demonstrate the potential of HEAs for efficient and sustainable hydrogen production.
文摘The present work reports the structural,optical,dielectric,and electrical properties of Eu-Er substituted M-type Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)(x=0.0.05,0.1,0.15,and 0.2)hexaferrites synthesized by sol-gel combustion method.The hexagonal structure of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples was confirmed from X-ray diffraction(XRD)analysis.The values of lattice parameters of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19)samples are increased as compared to Ba_(0.5)Sr_(0.5)Fe_(12)O_(19) sample.This increase in the value of lattice parameters is attributed to the substitution of larger cations(Eu^(3+)and Er^(3+))in place of smaller cations(Fe^(3+)ions).The crystallite sizes of the Ba0.5Sr0.5EuxErxFe12-2x019 samples also increase due to the substitution of larger cations.The force constants(K_o and K_t)increases with increasing Eu-Er concentration.The octahedral cluster shifts towards the higher wavenumber side whereas the tetrahedral cluster shifts towards the lower wavenumber side due to Eu-Er substitution in the Fourier transform infrared(FTIR)spectra.The photoluminescence(PL)emission spectra for the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples are observed at 365 nm.The dielectric dispersion in the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples can be understood by Koop's theory and Maxwell-Wagner type of inte rfacial polarization.Using Jonscher's power law and the co rrelated barrier hopping(CBH)model,the frequency and temperature-dependent be haviour of ac conductivity of Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples are described.The temperature-dependent behaviour of the dc conductivity of the Ba_(0.5)Sr_(0.5)Eu_(x)Er_(x)Fe_(12-2x)O_(19) samples is explained by the variable range hopping(VRH)model.The Motto temperature of the sample varies from 4.55×10^(9) to 2.31×10^(8) K.The estimated maximum barrier height(WM)of the compound varies from 0.6603 to 0.1199 eV.The temperature coefficient and activation energy of the samples were also calculated as a function of Eu-Er concentration.
文摘Dose estimation and quality control in computed tomography (CT) scanners are useful in controlling the dose of radiation given to patients while tests are carried out. The study was performed in a 16-slice Computed Tomography (CT) system of LightSpeed RT16 Xtra CT scanner. Quality control was done using a vendor-provided QA Phantom, and the six aspects of image quality were measured. For CT dosimetry, Computed Tomography Dose index volume (CTDIvol) was performed using Computed Tomography Dose Index (CTDI) Phantom. CTDI Phantom consists of three parts: Pediatric Head, Adult Head, and Adult Body Phantom. A 10 cm long pencil ion chamber DCT-10 was used to measure the dose at different positions inside the CTDI Phantom. Data were collected using MagicMax Universal software. For dose estimation of the CTDIvol Report of AAPM Task Group, 96 and 111 formalisms were used. For Pediatric Head, Adult Head, and Adult Body Phantom the measured CIDIvol was 61.04 mGy, 48.11 mGy, and 18.08 mGy respectively. The study has shown deviations of 7%, 15%, and 19% between estimated and console-displayed doses for Pediatric Head, Adult Head, and Adult Body scan techniques respectively. The six aspects of image quality measured by QA Phantom were found to be compatible with the specifications of the machine and CTDIvol measured by CTDI Phantom were found within a tolerance limit of ±20%. Hence, the QC and dosimetry of the mentioned machine are within the limit.
基金was supported by the U.S.Department of Energy(DOE),Office of Science,Office of Basic Energy Sciences,Division of Chemical Sciences,Geosciences,and Biosciences,Condensed Phase and Interfacial Molecular Science program,FWP 16248.
文摘MgATP is a stable complex formed by the chelation of Mg^(2+)with deprotonated adenosine-5'-triphosphate(ATP).In the cellular environment,MgATP plays a critical role in ATP hydrolysis,releasing substantial energy to support essential biological functions.To understand the structure and stabilization mechanism of MgATP,we conducted a joint negative ion photoelectron spectroscopic and computational study of the[ATP^(4-)·Mg^(2+)]^(2-)complex dianion,using[ATP^(4-)·2H^(+)]^(2-)as a reference.The experimentally determined adiabatic and vertical detachment energies(ADE and VDE)of[ATP^(4-)·Mg^(2+)]^(2-)at 20 K are 3.51±0.05 eV and 3.82±0.05 eV,respectively.The major spectral features of[ATP^(4-)·Mg^(2+)]^(2-)are attributed to two theoretically identified isomers with unfolded geometries,which are stabilized primarily by electrostatic interactions between Mg^(2+)and the triphosphate and ribose groups,with four deprotonated oxygens forming a pseudo-tetrahedral coordination.In contrast,[ATP^(4-)·2H^(+)]^(2-)exhibits a fundamentally different stabilization mechanism.Although most of the fifteen identified[ATP^(4-)·2H^(+)]^(2-)isomers also adopt unfolded geometries,they are primarily stabilized by intramolecular hydrogen bonds within the triphosphate group and between triphosphate and ribose groups.The interaction between ATP^(4-)and two protons is found to be much weaker than that with Mg^(2+),and[ATP^(4-)·2H^(+)]^(2-)exhibits substantial structural flexibility compared to[ATP^(4-)·Mg^(2+)]^(2-)due to the conformational constraint of the triphosphate chain by Mg^(2+).Thirteen[ATP^(4-)·2H^(+)]^(2-)isomers with unfolded geometries likely account for the major high-EBE(electron-binding-energy)spectral features.Notably,for the first time,a low EBE and temperature-dependent spectral feature is observed and attributed to two folded isomers of[ATP^(4-)·2H^(+)]^(2-),which exist at 20 K but disappear at room temperature.This study provides valuable molecular-level insights into cellular MgATP that resides within the hydrophobic pockets of proteins.
基金Project supported by the National Natural Science Foundations of China (Grant Nos. 11675119,12275136,and 12075001)the Nankai Zhide Foundations。
文摘Quantum interferometric power(IP), a discordlike measure, plays an important role in quantum metrology. We study the dynamics of IP for two-qubit X-shape states under different noisy environments. Our study shows that IP exhibits sudden change, and one side quantum channel is enough for the occurrence of a sudden change of IP. In particular, we show that the initial state having no sudden change of quantum discord exhibits a sudden change of IP under the dynamics of amplitude noise, but the converse is not true. Besides, we also investigate the dynamics of IP under two different kinds of composite noises. Our results also confirm that sudden change of IP occurs under such composite noises.
基金financially supported by the National Natural Science Foundation of China (No.22372057)Yunnan Fundamental Research Projects (No.202301AT070059)+2 种基金the Natural Science Foundation of Hunan Province (No.2023JJ30121)the Natural Science Foundation of Changsha (No.KQ2208259)the Fundamental Research Funds for the Central Universities (No.202044011)。
文摘Perovskite oxides have shown great potential application in fuel cells due to the unique crystal structures and tunable composition as well as effective capability toward the oxygen reduction reaction(ORR),whereas the investigation on the electrocatalytic performance of perovskite oxides toward the two-electron ORR to H_(2)O_(2)production remains very limited.Herein,a facile synthetic method has been developed to prepare La_(2)Sn_(2)O_(7)@La-doped ZnSnO_(3)heterostructures comprising of amorphous La_(2)Sn_(2)O_(7)and crystalline La-doped ZnSnO_(3).The optimal La_(2)Sn_(2)O_(7)@Ladoped ZnSnO_(3)heterostructures catalyst exhibits a significantly improved two-electron ORR performance to H_(2)O_(2)production with onset potential of 0.77 V and large current density of 2.51 m A.cm^(-2)at 0.1 V compared to ZnSnO_(3)(0.75 V,1.80 m A.cm^(-2),0.11 m A) as well as maintains high H_(2)O_(2)selectivity of 80%,which has been theoretically demonstrated to be contributed to the synergistic effect of amorphous La_(2)Sn_(2)O_(7)and crystalline La-doped ZnSnO_(3).Moreover,high H_(2)O_(2)yield rate of 2.9 m M.h^(-1)at 0.1 V can be achieved with a superior turnover frequency(TOF) of3.31 × 10^(-2)s^(-1)compared to the ZnSnO_(3)catalyst(2.10 × 10^(-2)s^(-1)).This work reveals the great potential of perovskite oxide as promising candidates for the environmentally friendly synthesis of hydrogen peroxide.
基金M Tahir is funded by EU H2020 Marie Skłodows-ka-Curie Fellowship(1439425).
文摘Graphitic carbon nitride(g-C_(3)N_(4))exhibits great mechanical as well as thermal characteristics,making it a valuable ma-terial for use in photoelectric conversion devices,an accelerator for synthesis of organic compounds,an electrolyte for fuel cell applications or power sources,and a hydrogen storage substance and a fluorescence detector.It is fabricated using dif-ferent methods,and there is a variety of morphologies and nanostructures such as zero to three dimensions that have been designed for different purposes.Ther e are many reports about g-C_(3)N_(4) in recent years,but a comprehensive review which covers nanostructure dimensions and their properties are missing.This review paper aims to give basic and comprehensive understanding of the photocatalytic and electrocatalytic usages of g-C_(3)N_(4).It highlights the recent progress of g-C_(3)N_(4) nano-structure designing by covering synthesis methods,dimensions,morphologies,applications and properties.Along with the summary,we will also discuss the challenges and prospects.Scientists,investigators,and engineers looking at g-C_(3)N_(4) nanostructures for a variety of applications might find our review paper to be a useful resource.
基金supported by the Technology Devel-opment Program(No.S3218794)funded by the Ministry of SMEs and Startups(MSS,Korea)supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by the Min-istry of Science and ICT(No.RS-2024-00446825).
文摘Strategic design and synergistic interactions between the electrodes and electroactive materials profoundly influence the energy storage efficiency of supercapacitor devices. Herein, we present the interfacial engineering of CoMoS_(4)-NiS_(2) with a well-defined construction of amorphous/crystalline hetero-phases deposited on carbon cloth using a hydrothermal technique. The optimal in-situ growth of CoMoS_(4)-NiS_(2)@CFC boasts an impressive areal capacity of 1341 mC cm^(-2) and retains ∼91 % capacity after 5000 cycles, attributed to the synergy effect and improved conductivity of multi-metallic sulfide ions over the CFC substrate. Density functional theory (DFT) reveals the metallic nature of CoMoS_(4)-NiS_(2)@CFC and favorable OH- ion adsorption energy of -4.35 eV, enhancing its charge storage capabilities. Furthermore, a hybrid supercapacitor (HSC) and Pouch HSC are assembled utilizing the CoMoS_(4)-NiS_(2)@CFC as a positrode and marine waste jellyfish-derived AC as a negatrode with an aqueous electrolyte. The HSC and PHSC demonstrate superior specific energies of 51.99 and 58.4 W h kg^(-1), respectively, along with corresponding specific powers of 800 and 780 W kg^(-1), maintaining robust stability of ∼90 % stability over 10000 cycles. Additionally, the HSC and PHSC have successfully illuminated several light-emitting diodes (LEDs) demonstrating superior energy storage performance. This work advances the design of hetero-phase multi-metal sulfides, paving the way for high-performance supercapacitor devices.
基金supported by the National Natural Science Foundation of China under Grant Nos.U2167204,11975040,111 Center(B20065)Brazilian authors were supported in part by local funding agencies CNPq+10 种基金FAPERJCAPESand INCT-FNA(Instituto Nacional de Ciência e Tecnologia,Física Nuclear e Aplicacoes)Research Project No.464898/2014-5Marco Siciliano's work was partially supported by the US Department of EnergyOffice of Scienceand Office of Nuclear Physics(DE-AC02-06CH11357)supported by Nuclear Energy Development and Research Project No.HNKF202224(28)Ling Chuang Research Project of the China National Nuclear Corporation No.CNNCLCKY-2023 and No.20221024000072F6-0002-7Guangdong Key Research and Development Program No.2020B040420005Guangdong Basic and Applied Basic Research Foundation No.2021B1515120027。
文摘The^(6)Li+^(89)Y experiment was performed to explore the reaction mechanism induced by a weakly bound nucleus^(6)Li and its cluster configuration.The particle-γcoincidence method was used to identify the different reaction channels.Theγ-rays coincident with^(3)He/^(3)H indicate that the^(3)H/^(3)He stripping reaction plays a significant role in the formation of Zr/Nb isotopes.The obtained results support the existence of a^(3)He-^(3)H cluster in^(6)Li.Direct and sequential transfer reactions are adequately discussed,and the FRESCO code is used to perform precise finite-range cyclic redundancy check calculations.In the microscopic calculation,direct cluster transfer is more predominant than sequential transfer in^(3)H transfer.However,the direct cluster transfer is of comparable magnitude to the sequential transfer in the^(3)He transfer.
基金Open access funding provided by The Science,Technology&Innovation Funding Authority(STDF)in cooperation with The Egyp-tian Knowledge Bank(EKB).
文摘The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life.Polyurethane(PU)-based materials have gained attention as promising candidates for supercapacitor electrodes,due to their flexibility,mechanical robustness,and tunable properties.It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms.Instead,PU serves as a flexible scaffold,a binder,or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment.Thus,the term'PU-based'in this review refers to PU-supported or PU-derived composites,where PU enables structural or functional integration of active electrode Materi-als.Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm^(2)with capacitance retention of 92%over 5,000 cycles.Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg,reflecting their potential for high-performance energy storage applications.Despite these advantages,challenges,such as low intrinsic conductivity and the environmental impact of traditional synthesis methods,limit their widespread adoption.Conventional PU composites often incorporate conductive additives like carbon materi-als,metal oxides,or conductive polymers to enhance their electrochemical performance,yet these approaches may involve non-renewable or toxic components.Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations.This includes using renewable resources,environmentally friendly process-ing techniques,and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies.This review highlights current trends in developing eco-friendly supercapacitor materials,addressing key challenges such as limited conductivity and complex processing.It uniquely integrates green chemistry principles with advances in polyurethane composites,emphasizing sustainable feedstocks,heteroatom doping,and functional nanomateri-als.By combining these aspects,this review provides a comprehensive perspective not fully covered in existing literature.
文摘Mossbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L （1.4306S）, Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690, at 1200℃ exposed in air and steam environments for 400 h. The basic aim was to identify and compare the iron oxides qualitatively and quantitatively, formed during the oxidation of these alloys in two environments. The behaviour of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam, whereas Sanicro-28 has excellent corrosion resistance in steam environment. In air oxidation of Inconel-690 no iron oxide, with established Mossbauer parameters, was detected.
文摘Poly(p-phenylenediamine)/chitosan (PPPDA/Chi) composite was prepared by in situ chemical oxidative polymerization of p-phenylenediamine (PPPDA) into chitosan (Chi) using ammonium persulphate (APS) as an oxidant. PPPDA and PPPDA/Chi composite were characterized by FT-IR spectra and SEM before and after copper loading. In batch adsorption method, the maximum removal of copper was experienced when 1 g/L of PPPDA and PPPDA/Chi composite dosages were used at pH 5.0 for PPPDA and 6.0 for PPPDA/Chi composite for 360 min for both sorbents. PPPDA showed adsorption capacity q<sub>e</sub><sup>max</sup> of 650 mg/g whereas its composite achieved q<sub>e</sub><sup>max</sup> of 573 mg/g. The experimental data correlate well with the Freundlich isotherm equation and the pseudo-second order kinetic model. The Cu(II), loaded PPPDA and its composite can be efficiently reused for as many as four cycles. The Cu(II)-loaded sorbents showed high antibacterial efficiency against Gram-positive and Gram-negative bacteria than their unloaded forms.
文摘We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation of ethylbenzene activities was measured in a round bottom flask immersed in oil bath at known reaction temperature. The physicochemical characteristics of the catalysts were examined by BET surface area, XRD, FT-IR and the oxidation activities were correlated with the acidities of the catalysts obtained by TPD of NH3. It was observed that both hydroxyapatite and USY （13% Na2O） supported Ni catalysts displayed higher ethylbenzene conversion and 80% selectivity towards acetophenone.
文摘Silver nanoparticles of mean size 16 nm were synthesized by inert gas condensation （IGC） method. Crystalline structure, morphology and nanoparticles size estimation were conducted by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. Antibacterial activity of these silver nanoparticles as a function of particles concentration against gram-negative bacterium Escherichia coli （E. coli） was carried out in liquid as well as solid growth media. Scanning electron microscopy （SEM） and TEM studies showed that silver nanoparticles after interaction with E.coli have adhered to and penetrated into the bacterial cells. Antibacterial properties of silver nanoparticles are attributed to their total surface area, as a larger surface to volume ratio of nanoparticles provides more efficient means for enhanced antibacterial activity.
基金PAKR and MS thank CSIR,New Delhi for funding this work under Emeritus Scientist Scheme
文摘Porous silica prepared by using an acrylic emulsion has been impregnated with bismuth ion resulting in Bi2Si05 species containing surface. The as-prepared materials have been characterized by X-ray diffraction spectroscopy （XRD）, X-ray photoelectron spectroscopy （XPS）, UV-Vis diffuse reflectance spectroscopy （UV-Vis DRS）, scanning electron microscopy （SEM）, energy dispersive analysis of X-ray （EDAX）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR） and N2 adsorption/desorption techniques. EDAX analysis confirms the penetration of bismuth ions into the framework of silica to form Bi2SiO5, which is substantiated by XRD. The UV-Vis DRS shows that the catalysts are optically active and XPS confirms the inclusion of bismuth into the framework of silica. FTIR spectra illustrate the formation of Bi-O-Si linkages in the porous silica framework. SEM and TEM show the spherical morphology, whereas N2 adsorption/desorption study confirms the porosity of the prepared materials. The photocatalytic activity of the material is evaluated for the degradation of isoproturon herbicide and it is found that the material is active as compared to the commercial P-25 Degussa TiO2.
