The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplan...The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplankton is important for interpretation of physiological and functional states of coastal ecosystems. The present study is focused on the structure and elemental composition of the phytoplankton assemblages from the different coastal zones by instrumental neutron activation analysis (INAA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). For the first time these complementary techniques were simultaneously applied to study the Black Sea phytoplankton. The concentrations of 45 elements in the coastal phytoplankton communities used as bioindicator of inorganic contamination of the Black Sea coastal area near Sevastopol, Ukraine, were determined. Phytoplankton samples were collected by total tows of the plankton net with 35 μm pore size at 3 stations situated in polluted and relatively pristine water areas of the Sevastopol coastal zone during autumn period of the phytoplankton growth. The concentration of Mg, Al, Sc, Ti, V, Mn, As, Rb, Ba, Th and Fe, Cr increases exponentially from relatively pristine station to more polluted station and 10-times and 3-times greater, respectively, in the phytoplankton of the Sevastopol Bay. The rare-earth elements have relatively the same concentration values less than 1 μg/g and tend to accumulate in the phytoplankton from the polluted station in the Sevastopol Bay. The obtained results are in a good agreement with the elemental concentration data in the oceanic plankton, plankton communities from the White Sea and the Black Sea. Using energy-dispersive X-ray spectrometry the mineral particles of unknown origin and impurities of copper (0.42% by weight) in the phytoplankton at the polluted station and zinc (0.57% by weight) at the relatively pristine station were determined.展开更多
The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these t...The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these techniques of the hair surfaces allows us to observe and study some marble fragments that can originate from the walls of the sarcophagus in which Maria-Magdalena’s remains were kept. These new findings support the authenticity of the hair as traditionally reported in the French “tradition des Saints de Provence”.展开更多
To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantit...To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.展开更多
Magnesium-lithium alloys with high lithium content have been attracting significant attention because of their low density,high formability and corrosion resistance.These properties are dependent on the distribution o...Magnesium-lithium alloys with high lithium content have been attracting significant attention because of their low density,high formability and corrosion resistance.These properties are dependent on the distribution of lithium,which is difficult to map in the presence of magnesium.In this work,a ratio spectrum-imaging method with electron energy-loss spectroscopy(EELS)is demonstrated,which enables the mapping of lithium.In application to LAZ941(Mg-9Li-4Al-1Zn in wt.%),this technique revealed that a key precipitate in the microstructure,previously thought by some to be Mg_(17)Al_(12),is in fact rich in lithium.This result was corroborated with a structural investigation by high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),showing this phase to be Al_(1-x)Zn_(x)Li,with x<<1.This work indicates the potential offered by this technique for mapping lithium in materials.展开更多
The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% Mn-5.2wt%Mo alloy were investigated by scanning electron microscopy(SEM),transmission electron m...The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% Mn-5.2wt%Mo alloy were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),and M(o|¨)ssbauer spectroscopy.The experimental results reveal that two types of thermal-induced martensites,e(hcp) andα'(bcc) martensites,are formed in the as-quenched condition,and these transformations have athermal characters.Mo addition to the Fe-Mn alloy does not change the coexistence ofεandα' martensites with the Mn content between 10wt%and 15wt%.Besides,M(o|¨)ssbauer spectra reveal a paramagnetic character with a singlet for theγ(fcc) austenite andεmartensite phases and a ferromagnetic character with a broad sextet for theα' martensite phase. The volume fraction ofα' martensite forming in the quenched alloy is much more than that of theεmartensite.展开更多
[ Objective] The aim was to study the application of scanning electron microscopy(SEM) on the physical property and ideological distri- bution of partials. [ Method] By dint of scanning electron microscopy, the morp...[ Objective] The aim was to study the application of scanning electron microscopy(SEM) on the physical property and ideological distri- bution of partials. [ Method] By dint of scanning electron microscopy, the morphological property of each source and main elements were analyzed. Compared with morphological property of sampling point, the source of particles was determined. [ Result] The results were consistent with the analysis of CMB8.2 chemical mass balance receptor model. Taking the four detection stations in Longyan Normal Training College, Minxi Vocational & Technical College, Longyan University, and Longyan Environment Monitoring Station as examples, the major air pollutants respectively were soil sand, dust of burning coal, second fugitive dust; soil sand, second fugitive dust, vehicle exhausts; second fugitive dust, soil; and second fugitive dust, vehicle exhausts, dust of burning coal. [ Conclusion] The study result had certain guiding significance to the analysis of sources of particles in the atmosphere and atmosphere environment treatment.展开更多
Electron microscopy has long been used in research in the fields of life sciences and materials sciences.Transmission and scanning electron microscopy and energy-dispersive X-ray spectroscopy(EDX)analyses have also be...Electron microscopy has long been used in research in the fields of life sciences and materials sciences.Transmission and scanning electron microscopy and energy-dispersive X-ray spectroscopy(EDX)analyses have also been performed in the field of gastroenterology.Electron microscopy and EDX enable(1)Observation of ultrastructural differences in esophageal epithelial cells in patients with gastroesophageal reflux and eosinophilic esophagitis;(2)Detection of lanthanum deposition in the stomach and duodenum;(3)Ultrastructural and elemental analyses of enteroliths and bezoars;(4)Detection and characterization of microorganisms in the gastrointestinal tract;(5)Diagnosis of gastrointestinal tumors with neuroendocrine differentiation;and(6)Analysis of gold nanoparticles potentially used in endoscopic photodynamic therapy.This review aims to foster a better understanding of electron microscopy applications by reviewing relevant clinical studies,basic research findings,and the state of current research carried out in gastroenterology science.展开更多
Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential c...Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential conductance spectra(dI/dV)of a single YPc2 molecule allow the characteristics of the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)to be identified.Furthermore,lateral distributions of the local density of states(LDOS)have also been obtained by dI/dV mapping and confirmed by first principles simulations.These electronic feature mappings and theoretical calculations provide a basis for understanding the unique STM morphology of YPc2,which is usually imaged as an eight-lobed structure.In addition,we demonstrate that bias-dependent STM morphologies and simultaneous dI/dV maps can provide a way of understanding the stability of two-dimensional YP_(c2) films.展开更多
In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the ...In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the mechanism is still under debate.Here,we report a detailed investigation of the superconducting properties near the QCP(x≈0.7) by utilizing scanning tunneling microscopy and spectroscopy.The temperature-dependent superconducting gap and magnetic vortex state were obtained and analyzed in the framework of the Bardeen-Cooper-Schrieffer model.The ideal isotropic s-wave superconducting gap excludes the long-speculated nematic fluctuations while preferring strong electron-phonon coupling as the mechanism for T_(C) enhancement near the QCP.The lower than expected gap ratio of Δ/(k_(B) T_(C)) is rooted in the fact that Ba_(1-x)Sr_(x)Ni_(2)As_(2) falls into the dirty limit with a serious pair breaking effect similar to the parent compound.展开更多
The influence of sodium silicate on the corrosion behaviour of aluminium alloy 7075-T6 in 0.1 M sodium chloride solution was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) tec...The influence of sodium silicate on the corrosion behaviour of aluminium alloy 7075-T6 in 0.1 M sodium chloride solution was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) techniques. Scanning electron microscopy (SEM) was used to characterize the AA7075-T6 surface. Silicate can significantly reduce corrosion deterioration and the inhibition efficiency increases with the concentration of Na<sub>2</sub>SiO<sub>3</sub>. The corrosion inhibition mechanism involves the formation of a protective film over the alloy surface by adsorption of aluminosilicate anions from solution, as has also been suggested by others in literature.展开更多
Complex oxide interfaces have been one of the central focuses in condensed matter physics and ma-terial science.Over the past decade,aberration corrected scanning transmission electron microscopy and spectroscopy has ...Complex oxide interfaces have been one of the central focuses in condensed matter physics and ma-terial science.Over the past decade,aberration corrected scanning transmission electron microscopy and spectroscopy has proven to be invaluable to visualize and understand the emerging quantum phenomena at an interface.In this paper,we briefly review some recent progress in the utilization of electron microscopy to probe interfaces.Specifically,we discuss several important challenges for electron microscopy to advance our understanding on interface phenomena,from the perspective of variable temperature,magnetism,electron energy loss spectroscopy analysis,electronic symmetry,and defects probing.展开更多
Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorp...Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorphous and crystalline structures of film were investigated by X-ray diffraction (XRD). The surface morphology of samples was examined by scanning electron microscopy (SEM). The composition and complex formation of films were characterized by Fourier transform infrared (FTIR) spectroscopy. The conductivity of the PAA-ZnA films was determined by electrochemical impedance spectroscopy. According to the XRD and FTIR analyses, all electrolyte films were in amorphous state and the existence of interaction between Zn2+ cations and the PAA structure confirms that the film was successfully prepared. The SEM observations reveal that the electrolyte films appeared to be rough and flat with irregularly shaped surfaces. The highest ionic conductivity (σ) of 1.82 × 10-5 Scm-1 was achieved at room temperature (303 K) for the sample containing 10 wt % ZnA.展开更多
The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have b...The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have been measured and their variation with concentration of the metal ion has been investigated. The resistivity of doped mullite decreases rapidly in the shorter temperature range and sharply in the higher temperature range. The decreasing resistivity is due to the 3d orbital electrons and the concentration of metal ions present. X-ray analysis confirms the presence of metal ions in mullite, which entered in the octahedral site. The Fe2+ and Cu2+ ions will substitute Al3+ ion in the octahedral site of mullite structure and most probably will be responsible for reducing the resistivity as well as the activation energy. Transition metal ion doped mullite-based ceramic can be considered as promising material as a substrate in the electronic industry, because of its reasonable atom density, its low activation characteristics, low thermal expansion coefficient and high mechanical strength. The present material we have developed has an activation energy of resistivity/band gap energy, Eg, 1.11 eV at 0.04 M concentration for Cu2+ ion.展开更多
The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute opti...The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray). Exploration by these techniques of a blood stain located on the face permits us to discover some red-colour particles (hematite, biotite and cinnabar) of exogenous material in this stain. We finally characterize these red-colour particles and try to explain their presences in the blood stain. Globally, all these red-colour particles cannot explain all of the reddish appearance of the area under study.展开更多
文摘The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplankton is important for interpretation of physiological and functional states of coastal ecosystems. The present study is focused on the structure and elemental composition of the phytoplankton assemblages from the different coastal zones by instrumental neutron activation analysis (INAA), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). For the first time these complementary techniques were simultaneously applied to study the Black Sea phytoplankton. The concentrations of 45 elements in the coastal phytoplankton communities used as bioindicator of inorganic contamination of the Black Sea coastal area near Sevastopol, Ukraine, were determined. Phytoplankton samples were collected by total tows of the plankton net with 35 μm pore size at 3 stations situated in polluted and relatively pristine water areas of the Sevastopol coastal zone during autumn period of the phytoplankton growth. The concentration of Mg, Al, Sc, Ti, V, Mn, As, Rb, Ba, Th and Fe, Cr increases exponentially from relatively pristine station to more polluted station and 10-times and 3-times greater, respectively, in the phytoplankton of the Sevastopol Bay. The rare-earth elements have relatively the same concentration values less than 1 μg/g and tend to accumulate in the phytoplankton from the polluted station in the Sevastopol Bay. The obtained results are in a good agreement with the elemental concentration data in the oceanic plankton, plankton communities from the White Sea and the Black Sea. Using energy-dispersive X-ray spectrometry the mineral particles of unknown origin and impurities of copper (0.42% by weight) in the phytoplankton at the polluted station and zinc (0.57% by weight) at the relatively pristine station were determined.
文摘The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these techniques of the hair surfaces allows us to observe and study some marble fragments that can originate from the walls of the sarcophagus in which Maria-Magdalena’s remains were kept. These new findings support the authenticity of the hair as traditionally reported in the French “tradition des Saints de Provence”.
基金Funded by the International Science&Technology Cooperation Program of Hubei Province of China(No.2022EHB024)。
文摘To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides.
基金the Australian Research Council (ARC) for funding this work[Grant no.DP190103592]the use of instruments and scientific and technical assistance at the Monash Centre for Electron Microscopy,a Node of Microscopy Australiafunded by ARC grants LE110100223(F20),LE0454166(Titan)and LE170100118(Spectra-φ)。
文摘Magnesium-lithium alloys with high lithium content have been attracting significant attention because of their low density,high formability and corrosion resistance.These properties are dependent on the distribution of lithium,which is difficult to map in the presence of magnesium.In this work,a ratio spectrum-imaging method with electron energy-loss spectroscopy(EELS)is demonstrated,which enables the mapping of lithium.In application to LAZ941(Mg-9Li-4Al-1Zn in wt.%),this technique revealed that a key precipitate in the microstructure,previously thought by some to be Mg_(17)Al_(12),is in fact rich in lithium.This result was corroborated with a structural investigation by high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),showing this phase to be Al_(1-x)Zn_(x)Li,with x<<1.This work indicates the potential offered by this technique for mapping lithium in materials.
基金supported by the Kirikkale University Scientific Research Fund(Nos.2008/34 and 2008/35)
文摘The kinetic,morphological,crystallographic,and magnetic characteristics of thermally induced martensites in Fe-13.4wt% Mn-5.2wt%Mo alloy were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),and M(o|¨)ssbauer spectroscopy.The experimental results reveal that two types of thermal-induced martensites,e(hcp) andα'(bcc) martensites,are formed in the as-quenched condition,and these transformations have athermal characters.Mo addition to the Fe-Mn alloy does not change the coexistence ofεandα' martensites with the Mn content between 10wt%and 15wt%.Besides,M(o|¨)ssbauer spectra reveal a paramagnetic character with a singlet for theγ(fcc) austenite andεmartensite phases and a ferromagnetic character with a broad sextet for theα' martensite phase. The volume fraction ofα' martensite forming in the quenched alloy is much more than that of theεmartensite.
基金Supported by Young Teacher Innovation Program of Jilin University(421031674425)Seed Fund of Jilin University (421021614425)
文摘[ Objective] The aim was to study the application of scanning electron microscopy(SEM) on the physical property and ideological distri- bution of partials. [ Method] By dint of scanning electron microscopy, the morphological property of each source and main elements were analyzed. Compared with morphological property of sampling point, the source of particles was determined. [ Result] The results were consistent with the analysis of CMB8.2 chemical mass balance receptor model. Taking the four detection stations in Longyan Normal Training College, Minxi Vocational & Technical College, Longyan University, and Longyan Environment Monitoring Station as examples, the major air pollutants respectively were soil sand, dust of burning coal, second fugitive dust; soil sand, second fugitive dust, vehicle exhausts; second fugitive dust, soil; and second fugitive dust, vehicle exhausts, dust of burning coal. [ Conclusion] The study result had certain guiding significance to the analysis of sources of particles in the atmosphere and atmosphere environment treatment.
文摘Electron microscopy has long been used in research in the fields of life sciences and materials sciences.Transmission and scanning electron microscopy and energy-dispersive X-ray spectroscopy(EDX)analyses have also been performed in the field of gastroenterology.Electron microscopy and EDX enable(1)Observation of ultrastructural differences in esophageal epithelial cells in patients with gastroesophageal reflux and eosinophilic esophagitis;(2)Detection of lanthanum deposition in the stomach and duodenum;(3)Ultrastructural and elemental analyses of enteroliths and bezoars;(4)Detection and characterization of microorganisms in the gastrointestinal tract;(5)Diagnosis of gastrointestinal tumors with neuroendocrine differentiation;and(6)Analysis of gold nanoparticles potentially used in endoscopic photodynamic therapy.This review aims to foster a better understanding of electron microscopy applications by reviewing relevant clinical studies,basic research findings,and the state of current research carried out in gastroenterology science.
基金The first author acknowledges the financial support of JSPS(Japan Society for the Promotion of Science)This work was also supported by an International Colla-borative Research Grant by the National Institute of Information and Communications Technology of Japan.
文摘Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential conductance spectra(dI/dV)of a single YPc2 molecule allow the characteristics of the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)to be identified.Furthermore,lateral distributions of the local density of states(LDOS)have also been obtained by dI/dV mapping and confirmed by first principles simulations.These electronic feature mappings and theoretical calculations provide a basis for understanding the unique STM morphology of YPc2,which is usually imaged as an eight-lobed structure.In addition,we demonstrate that bias-dependent STM morphologies and simultaneous dI/dV maps can provide a way of understanding the stability of two-dimensional YP_(c2) films.
基金Project supported by the National Key R&D Program of China (Grant Nos. 2022YFA1403203, 2022YFA1403400, and 2021YFA1400400)the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302802)+2 种基金the National Natural Science Foundation of China (Grant Nos. 12074002, 12104004, 12204008, and 12374133)the Chinese Academy of Sciences (Grant Nos. XDB33000000 and GJTD-2020-01)the Major Basic Program of Natural Science Foundation of Shandong Province (Grant No. ZR2021ZD01)。
文摘In the phase diagram of the nickel-based superconductor Ba_(1-x)Sr_(x)Ni_(2)As_(2),T_(C) has been found to be enhanced sixfold near the quantum critical point(QCP) x=0.71 compared with the parent compound.However,the mechanism is still under debate.Here,we report a detailed investigation of the superconducting properties near the QCP(x≈0.7) by utilizing scanning tunneling microscopy and spectroscopy.The temperature-dependent superconducting gap and magnetic vortex state were obtained and analyzed in the framework of the Bardeen-Cooper-Schrieffer model.The ideal isotropic s-wave superconducting gap excludes the long-speculated nematic fluctuations while preferring strong electron-phonon coupling as the mechanism for T_(C) enhancement near the QCP.The lower than expected gap ratio of Δ/(k_(B) T_(C)) is rooted in the fact that Ba_(1-x)Sr_(x)Ni_(2)As_(2) falls into the dirty limit with a serious pair breaking effect similar to the parent compound.
文摘The influence of sodium silicate on the corrosion behaviour of aluminium alloy 7075-T6 in 0.1 M sodium chloride solution was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) techniques. Scanning electron microscopy (SEM) was used to characterize the AA7075-T6 surface. Silicate can significantly reduce corrosion deterioration and the inhibition efficiency increases with the concentration of Na<sub>2</sub>SiO<sub>3</sub>. The corrosion inhibition mechanism involves the formation of a protective film over the alloy surface by adsorption of aluminosilicate anions from solution, as has also been suggested by others in literature.
基金supported by the US Department of Energy(DOE)under Grant No.DOE DE-SC0002136.Z.W.and Y.Z.acknowledge the support by the U.S.Department of Energy,Office of Basic Energy Science,Division of Materials Science and Engineering,under contract no.DESC0012704H.G.acknowledges the support by Shanghai Municipal Natural Science Foundation(No.19ZR1402800)Shanghai Municipal Natural Science Foundation(No.18JC1411400).
文摘Complex oxide interfaces have been one of the central focuses in condensed matter physics and ma-terial science.Over the past decade,aberration corrected scanning transmission electron microscopy and spectroscopy has proven to be invaluable to visualize and understand the emerging quantum phenomena at an interface.In this paper,we briefly review some recent progress in the utilization of electron microscopy to probe interfaces.Specifically,we discuss several important challenges for electron microscopy to advance our understanding on interface phenomena,from the perspective of variable temperature,magnetism,electron energy loss spectroscopy analysis,electronic symmetry,and defects probing.
文摘Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorphous and crystalline structures of film were investigated by X-ray diffraction (XRD). The surface morphology of samples was examined by scanning electron microscopy (SEM). The composition and complex formation of films were characterized by Fourier transform infrared (FTIR) spectroscopy. The conductivity of the PAA-ZnA films was determined by electrochemical impedance spectroscopy. According to the XRD and FTIR analyses, all electrolyte films were in amorphous state and the existence of interaction between Zn2+ cations and the PAA structure confirms that the film was successfully prepared. The SEM observations reveal that the electrolyte films appeared to be rough and flat with irregularly shaped surfaces. The highest ionic conductivity (σ) of 1.82 × 10-5 Scm-1 was achieved at room temperature (303 K) for the sample containing 10 wt % ZnA.
文摘The crystallized mullite composite has been synthesized via sol-gel technique in the presence of transition metal ions such as iron and copper. The electrical resistivity and activation energy of the composites have been measured and their variation with concentration of the metal ion has been investigated. The resistivity of doped mullite decreases rapidly in the shorter temperature range and sharply in the higher temperature range. The decreasing resistivity is due to the 3d orbital electrons and the concentration of metal ions present. X-ray analysis confirms the presence of metal ions in mullite, which entered in the octahedral site. The Fe2+ and Cu2+ ions will substitute Al3+ ion in the octahedral site of mullite structure and most probably will be responsible for reducing the resistivity as well as the activation energy. Transition metal ion doped mullite-based ceramic can be considered as promising material as a substrate in the electronic industry, because of its reasonable atom density, its low activation characteristics, low thermal expansion coefficient and high mechanical strength. The present material we have developed has an activation energy of resistivity/band gap energy, Eg, 1.11 eV at 0.04 M concentration for Cu2+ ion.
文摘The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray). Exploration by these techniques of a blood stain located on the face permits us to discover some red-colour particles (hematite, biotite and cinnabar) of exogenous material in this stain. We finally characterize these red-colour particles and try to explain their presences in the blood stain. Globally, all these red-colour particles cannot explain all of the reddish appearance of the area under study.