Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and adaptability.Their unique physical and chemical characteristics make them extremely intriguing as materials for num...Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and adaptability.Their unique physical and chemical characteristics make them extremely intriguing as materials for numerous high-potential applications,such as electronics and gas sensing.This study focused on producing carbon-based nanomaterial devices by deposition of flame-formed carbon nanoparticles on a suitable substrate and investigating their gas-sensing properties.CNPs were produced in a fuel-rich laminar premixed ethylene/air flame and the collected CNP film was morphologically and electrically characterized.The electrical conductivity of the film was investigated as a function of ethanol concentration and amount of deposited material.Notably,CNP films exhibited high sensitivity to ambient ethanol gas concentrations,and rapid recovery times at room temperature,and showed a sensitivity increasing with the amount of deposited material and the surface complexity.Our findings demonstrate the high potential of combustion-generated CNPs as building materials for low-cost and portable ethanol sensors.展开更多
Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend...Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend on the nature and density of dust.The nature of dust was studied by means of scanning electron microscopy and energy dispersive x-ray spectroscopy.It was found that the granulometry of dust particles depends on the study area.For a dust density of around 20 g/m^(2),the maximum power Pmax of the solar panel decreases drastically from 30 to 20 W for the(HP)site,and no more than 14 W for the(AD)site.The diversity of the behavior of the soiled panel was explained in terms of the size of the particles collected from each area.The transmission of light across the front glass of the PV panel is more affected when the sizes of particles are small.展开更多
The work deals with the epitaxial PbSe layers grown on the KCl substrates by the method of “hot-wall” molecular epitaxy over the range of layer thicknesses of 20 - 2000 nm. Special emphasis is put on the values of e...The work deals with the epitaxial PbSe layers grown on the KCl substrates by the method of “hot-wall” molecular epitaxy over the range of layer thicknesses of 20 - 2000 nm. Special emphasis is put on the values of elastic deformations that could be generated and frozen in epitaxial layers with the aim of influencing their energy spectra and optical properties. The maximum deformation at layers tension made up 57% of the initial mismatch between the layer and the substrate (ε = Δa/a = 0.015). In such a solid-state structure effective “negative” pressure is realized, which is justified by increase in the tangential lattice constant and the forbidden gap width. This width correlates with the tangential lattice constant (deformation) and corresponds to certain values of definite frequencies of direct electron transitions across the forbidden gap.展开更多
TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crysta ls in the visible and near-infrared wavelength region, hi...TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crysta ls in the visible and near-infrared wavelength region, high dielectric constant, wide band gap, high wear resistance and stability, etc, for which make it being used in many fields. This paper aims to investigate the optical characterizatio n of thin film TiO2 on silicon wafer. The TiO2 thin films were prepared by DC re active magnetron sputtering process from Ti target. The reflectivity of the film s was measured by UV-3101PC, and the index of refraction (n) and extinction coef ficient (k) were measured by n & k Analyzer 1200.展开更多
Fe-X-Ni(X=Cr,W and V)combinatorial thin-film(∼100 nm thick)materials chips covering the full composition range of ternary systems were fabricated.The crystal structure distribution was mapped by micro-beam X-ray diff...Fe-X-Ni(X=Cr,W and V)combinatorial thin-film(∼100 nm thick)materials chips covering the full composition range of ternary systems were fabricated.The crystal structure distribution was mapped by micro-beam X-ray diffractometers(XRD)and the magnetic hysteresis loops over the chip were characterized by a high-throughput magneto-optical Kerr effect(HT-MOKE)system to establish the composition-phase-magnetic properties relationships.The results showed that saturation magnetization for all systems has a strong dependency on alloying composition,and decreases with increasing dopped elements content as a general trend.Although the trend of saturation magnetization in bulk is in good agreement with that from thin films,all bulk samples show almost no coercivity,attributable to the much smaller grain size,and stronger texture in thin-film samples.Comparing the Fe-X-Ni systems under a similar condition,in the out-of-plane,Cr alloying obtained the largest coercivity(∼400 mT)followed by W alloying(∼300 mT)and then V alloying(∼200 mT).We suggest that alloying with different elements leads to the diverse orientation and crystallinity of the fcc phase resulting in different magnetic properties.Meanwhile,the effect of heat treatment on magnetic properties indicates that saturation magnetization is more closely related to the duration of heat treatment.展开更多
A soluble poly（2-methoxy-5-decoxy）-p-phenylene vinylene （PMODOPV） was synthesized via dehydrochlorination reaction and characterized by UV-visible absorption spectrum. The results showed that PMODOPV had a broad o...A soluble poly（2-methoxy-5-decoxy）-p-phenylene vinylene （PMODOPV） was synthesized via dehydrochlorination reaction and characterized by UV-visible absorption spectrum. The results showed that PMODOPV had a broad optical absorption band in the range of 450--550 nm and the optical band gap was calculated to be around 2.12 eV. The third-order nonlinear optical susceptibilities （X^（3）） of PMODOPV films implanted by 30-keV N^＋ ions in the dose range of 3.8 × 10^15-9.6 × 10^16 ions/cm^2 were measured by degenerate four-wave mixing （DFWM） technique. The results demonstrated that the resonant and offresonant X^（3） values were all enhanced significantly by means of ion implantation. The maximum resonant X^（3） value of 9.67 × 10^-9 esu at 532 nm and off-resonant X^（3） value of 2.49 × 10^-10 esu at 1.064 μm were obtained when the ion dose was 3.8 × 10^16 ions/cm^2.展开更多
In this work, we introduce position-resolved surface characterization and nanofabrication using an optical microscope(OM) combined with a nanopipette-based quartz tuning fork atomic force microscope(nanopipette/QTF-AF...In this work, we introduce position-resolved surface characterization and nanofabrication using an optical microscope(OM) combined with a nanopipette-based quartz tuning fork atomic force microscope(nanopipette/QTF-AFM) system. This system is used to accurately determine substrate position and nanoscale phenomena under ambient conditions. Solutions consisting of 5 nm Au nanoparticles, nanowires, and polydimethylsiloxane(PDMS) are deposited onto the substrate through the nano/microaperture of a pulled pipette. Nano/microscale patterning is performed using a nanopipette/QTF-AFM, while position is resolved by monitoring the substrate with a custom OM. With this tool, one can perform surface characterization(force spectroscopy/microscopy) using the quartz tuning fork(QTF) sensor. Nanofabrication is achieved by accurately positioning target materials on the surface, and on-demand delivery and patterning of various solutions for molecular architecture.展开更多
基金supported by the Italian Ministry of Education,Universities and Research(MIUR)through the PRIN 2017 program(Project No.2017PJ5XXX“MAGIC DUST”).
文摘Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and adaptability.Their unique physical and chemical characteristics make them extremely intriguing as materials for numerous high-potential applications,such as electronics and gas sensing.This study focused on producing carbon-based nanomaterial devices by deposition of flame-formed carbon nanoparticles on a suitable substrate and investigating their gas-sensing properties.CNPs were produced in a fuel-rich laminar premixed ethylene/air flame and the collected CNP film was morphologically and electrically characterized.The electrical conductivity of the film was investigated as a function of ethanol concentration and amount of deposited material.Notably,CNP films exhibited high sensitivity to ambient ethanol gas concentrations,and rapid recovery times at room temperature,and showed a sensitivity increasing with the amount of deposited material and the surface complexity.Our findings demonstrate the high potential of combustion-generated CNPs as building materials for low-cost and portable ethanol sensors.
文摘Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend on the nature and density of dust.The nature of dust was studied by means of scanning electron microscopy and energy dispersive x-ray spectroscopy.It was found that the granulometry of dust particles depends on the study area.For a dust density of around 20 g/m^(2),the maximum power Pmax of the solar panel decreases drastically from 30 to 20 W for the(HP)site,and no more than 14 W for the(AD)site.The diversity of the behavior of the soiled panel was explained in terms of the size of the particles collected from each area.The transmission of light across the front glass of the PV panel is more affected when the sizes of particles are small.
文摘The work deals with the epitaxial PbSe layers grown on the KCl substrates by the method of “hot-wall” molecular epitaxy over the range of layer thicknesses of 20 - 2000 nm. Special emphasis is put on the values of elastic deformations that could be generated and frozen in epitaxial layers with the aim of influencing their energy spectra and optical properties. The maximum deformation at layers tension made up 57% of the initial mismatch between the layer and the substrate (ε = Δa/a = 0.015). In such a solid-state structure effective “negative” pressure is realized, which is justified by increase in the tangential lattice constant and the forbidden gap width. This width correlates with the tangential lattice constant (deformation) and corresponds to certain values of definite frequencies of direct electron transitions across the forbidden gap.
基金This work was supported by the National Natural Science Foundation of China(No,50376067)the Plan for Science&Technology Development of Guangzhou(2001-Z-117-01).
文摘TiO2 thin film has attracted considerable attention in recent years, due to its different refractive index and transparency with amorphous and different crysta ls in the visible and near-infrared wavelength region, high dielectric constant, wide band gap, high wear resistance and stability, etc, for which make it being used in many fields. This paper aims to investigate the optical characterizatio n of thin film TiO2 on silicon wafer. The TiO2 thin films were prepared by DC re active magnetron sputtering process from Ti target. The reflectivity of the film s was measured by UV-3101PC, and the index of refraction (n) and extinction coef ficient (k) were measured by n & k Analyzer 1200.
基金We are grateful for the financial support from the National Key Research and Development Program of China(Grant Nos.2021YFB3702102 and 2017YFB0701900)the Major Science and Technology Project of Yunnan Province“Genome Engineering of Rare and Precious Metal Materials in Yunnan Province(Phase One 2020)"(Grant No.202002AB080001-1)Boyue Instruments(Shanghai)Co.,Ltd for support of m-XRF is also acknowledged。
文摘Fe-X-Ni(X=Cr,W and V)combinatorial thin-film(∼100 nm thick)materials chips covering the full composition range of ternary systems were fabricated.The crystal structure distribution was mapped by micro-beam X-ray diffractometers(XRD)and the magnetic hysteresis loops over the chip were characterized by a high-throughput magneto-optical Kerr effect(HT-MOKE)system to establish the composition-phase-magnetic properties relationships.The results showed that saturation magnetization for all systems has a strong dependency on alloying composition,and decreases with increasing dopped elements content as a general trend.Although the trend of saturation magnetization in bulk is in good agreement with that from thin films,all bulk samples show almost no coercivity,attributable to the much smaller grain size,and stronger texture in thin-film samples.Comparing the Fe-X-Ni systems under a similar condition,in the out-of-plane,Cr alloying obtained the largest coercivity(∼400 mT)followed by W alloying(∼300 mT)and then V alloying(∼200 mT).We suggest that alloying with different elements leads to the diverse orientation and crystallinity of the fcc phase resulting in different magnetic properties.Meanwhile,the effect of heat treatment on magnetic properties indicates that saturation magnetization is more closely related to the duration of heat treatment.
基金This work was supported by the National Natural Sci-ence Foundation of China under Grant No. 60277002 the Scientific Research Foundation of Xi'an Jiao-tong University.
文摘A soluble poly（2-methoxy-5-decoxy）-p-phenylene vinylene （PMODOPV） was synthesized via dehydrochlorination reaction and characterized by UV-visible absorption spectrum. The results showed that PMODOPV had a broad optical absorption band in the range of 450--550 nm and the optical band gap was calculated to be around 2.12 eV. The third-order nonlinear optical susceptibilities （X^（3）） of PMODOPV films implanted by 30-keV N^＋ ions in the dose range of 3.8 × 10^15-9.6 × 10^16 ions/cm^2 were measured by degenerate four-wave mixing （DFWM） technique. The results demonstrated that the resonant and offresonant X^（3） values were all enhanced significantly by means of ion implantation. The maximum resonant X^（3） value of 9.67 × 10^-9 esu at 532 nm and off-resonant X^（3） value of 2.49 × 10^-10 esu at 1.064 μm were obtained when the ion dose was 3.8 × 10^16 ions/cm^2.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (2013-056344)Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education,Science and Technology (2013R1A6A3A03063900)+1 种基金support from Center for Nano-Liquidsupport from the National Science Foundation OISE Grant #0853104
文摘In this work, we introduce position-resolved surface characterization and nanofabrication using an optical microscope(OM) combined with a nanopipette-based quartz tuning fork atomic force microscope(nanopipette/QTF-AFM) system. This system is used to accurately determine substrate position and nanoscale phenomena under ambient conditions. Solutions consisting of 5 nm Au nanoparticles, nanowires, and polydimethylsiloxane(PDMS) are deposited onto the substrate through the nano/microaperture of a pulled pipette. Nano/microscale patterning is performed using a nanopipette/QTF-AFM, while position is resolved by monitoring the substrate with a custom OM. With this tool, one can perform surface characterization(force spectroscopy/microscopy) using the quartz tuning fork(QTF) sensor. Nanofabrication is achieved by accurately positioning target materials on the surface, and on-demand delivery and patterning of various solutions for molecular architecture.
