A vacuum ultraviolet(VUV)spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced Superconducting Tokamak(EAST).In this study,wavelength c...A vacuum ultraviolet(VUV)spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced Superconducting Tokamak(EAST).In this study,wavelength calibration for the VUV spectroscopy is achieved utilizing a zinc lamp.The grating angle and charge-coupled device(CCD)position are carefully calibrated for different wavelength positions.The wavelength calibration of the VUV spectroscopy is crucial for improving the accuracy of impurity spectral data,and is required to identify more impurity spectral lines for impurity transport research.Impurity spectra of EAST plasmas have also been obtained in the wavelength range of 50–300 nm with relatively high spectral resolution.It is found that the impurity emissions in the edge region are still dominated by low-Z impurities,such as carbon,oxygen,and nitrogen,albeit with the application of fulltungsten divertors on the EAST tokamak.展开更多
In this paper,an absorption spectroscopy measurement method was applied on two atmospheric pressure plasma sources to determine their production of nitric oxide.The concentrations are essential for evaluating the plas...In this paper,an absorption spectroscopy measurement method was applied on two atmospheric pressure plasma sources to determine their production of nitric oxide.The concentrations are essential for evaluating the plasma sources based on the principle of the Dielectric Barrier Discharge(DBD)for applications in plasma medicine.The described method is based on a setup with an electrodeless discharge lamp filled with a mixture of oxygen and nitrogen.One of the emitted wavelengths is an important resonance wavelength of nitric oxide(λ = 226.2 nm).By comparing the absorption behaviour at the minimum and maximum of the spectral absorption cross section of nitric oxide around that wavelength,and measuring the change in intensity by the absorbing plasma,the concentration of nitric oxide inside the plasma can be calculated.The produced nitric oxide concentrations depend on the pulse duration and are in the range of 180 ppm to 1400 ppm,so that a distance of about 10 cm to the respiratory tract is enough to conform to the VDI Guideline 2310.展开更多
Methanol/TiO2(110) is a model system in the surface science study of photocatalysis where methanol is taken as a hole capture. However, the highest occupied molecular orbital of adsorbed methanol lies below the vale...Methanol/TiO2(110) is a model system in the surface science study of photocatalysis where methanol is taken as a hole capture. However, the highest occupied molecular orbital of adsorbed methanol lies below the valence band maximum of TiO2, preventing the hole transfer. To study the level alignment of this system, electronic structure of methanol covered TiO2(110) surface has been measured by ultraviolet photoelectron spectroscopy and the molecular orbitals of adsorbed methanol have been clearly identified. The results indicate the weak interaction between methanol and TiO2 substrate. The static electronic structure also suggests the mismatch of the energy levels. These static experiments have been performed without band gap excitation which is the prerequisite of a photocatalytie process. Future study of the transient electronic structure using time-resolved UPS has also been discussed.展开更多
Single crystalline ZnO nanorods were prepared by the hydrothermal method with synthesized ZnCl2·4Zn(OH)2 as the precursor. Morphologies of the nanorods were controlled by various reaction conditions with cetylt...Single crystalline ZnO nanorods were prepared by the hydrothermal method with synthesized ZnCl2·4Zn(OH)2 as the precursor. Morphologies of the nanorods were controlled by various reaction conditions with cetyltrimethylammonium bromide (CTAB) as the modifying agent. The nanorods were characterized by XRD, TEM, UV-Vis spectra, and IR spectra. The microstructure of holes in nanosize was observed on the surface of the nanorods. The UV-Vis spectra indicate that the as-prepared ZnO nanorods have absorption of visible-hght as well as ultraviolet-light. Therefore, these nanorods may be good candidates for visible-light photocatalysis materials from the viewpoint of practical applications. The reason for visible-light absorption was discussed in this article.展开更多
Semiconductors are a major category of functional materials essential to various applications to sustain the modern society.Most applied materials or devices utilizing semiconductors are enabled by interfaces or junct...Semiconductors are a major category of functional materials essential to various applications to sustain the modern society.Most applied materials or devices utilizing semiconductors are enabled by interfaces or junctions,such as solar cells,electronic/photonic devices,environmental sensors,and redox hetero-catalysts.Herein,the author provides a critical commentary on photoemission measurement of the work function and,more importantly,the electron affinity of semiconductors essential for energy band diagram of heterojunctions.Particular effort is made towards addressing complications associated with Fermi level pinning due to surficial states of doped semiconductors.展开更多
Two-dimensional ultraviolet(2 DUV) spectroscopy is a novel technology for probing molecular structure. We have developed a generalized quantum mechanics/molecular mechanics(QM/MM) approach to simulate the electronic t...Two-dimensional ultraviolet(2 DUV) spectroscopy is a novel technology for probing molecular structure. We have developed a generalized quantum mechanics/molecular mechanics(QM/MM) approach to simulate the electronic transitions of protein backbones and aromatic amino acids in aqueous solution. These transitions, which occur in the ultraviolet(UV) region, provide a sensitive probe of molecular structure. The features of 2 DUV spectra are accurately characterized and enable us to trace small variations in the structure and dynamics as well as evolution propensity with high accuracy. Various structures and dynamic phenomena are investigated to construct a systematic framework for 2 DUV simulation mechanisms, so as to explore further applications of this technique. In this feature article, we summarize the theory and applications of 2 DUV spectroscopy we have engaged in recently, present the important roles of 2 DUV spectroscopy, and outline directions for future development. We hope this article can offer a platform for more scientists in different research fields to gain a clear overview of 2 DUVand further attract more people to explore this promising field.展开更多
Some new complexes RE2(EDODA)3·3H2O, where RE = La, Nd, Eu, Gd, Tb, Er, Yb, Lu and Y, EDODA = ethylene-1,2-dioxydiacetate, have been synthesized and characterized by elemental analysis, molar conductance, IR...Some new complexes RE2(EDODA)3·3H2O, where RE = La, Nd, Eu, Gd, Tb, Er, Yb, Lu and Y, EDODA = ethylene-1,2-dioxydiacetate, have been synthesized and characterized by elemental analysis, molar conductance, IR spectra, UV spectra, TG-DTA, 1H NMR and 13C NMR spectra. Various analyses indicate that the complexes are of nine-coordinated binuclear structure. The carboxylates are bidentate ligands and the ether oxygen atoms also coordinate to rare earth ions. Three water molecules are crystalline water. In addition, the influence of concentration on the chemical shift has been studied through the 1H NMR spectra of the complex Lu2(EDODA)3·3H2O in different concentrations.展开更多
In this work, the nickel-aluminum layered double hydroxide (Ni-Al LDH) with nitrate interlayer anion was synthesized and used as a solid phase extraction sorbent for the selective separation and pre-concentration of...In this work, the nickel-aluminum layered double hydroxide (Ni-Al LDH) with nitrate interlayer anion was synthesized and used as a solid phase extraction sorbent for the selective separation and pre-concentration of mefenamic acid prior to quantification by UV detection at λmax ? 286 nm. Extraction procedure is based on the adsorption of mefenamate anions on the Ni-Al(NO3? ) LDH and/or their exchange with LDH interlayer NO3? anions. The effects of several parameters such as cations and interlayer anions type in LDH structure, pH, sample flow rate, elution conditions, amount of nano-sorbent and co-existing ions on the extraction were investigated and optimized. Under the optimum conditions, the calibration graph was linear within the range of 2-1000 mg/L with a correlation coefficient of 0.9995. The limit of detection and relative standard deviation were 0.6 mg/L and 0.84% (30 mg/L, n ? 6), respectively. The presented method was successfully applied to determine of mefenamic acid in human serum and pharmaceutical wastewater samples.展开更多
Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching process...Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF_(4)/Ar ratio of 50:50 sccm. Regardless of the ratio of CF_(4) to Ar,the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF-4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication.展开更多
Multivariate analysis and filtering techniques are widely applied to simultaneous and/or selective determination of multicomponent systems. Many methods among them are based on the principle of linear addition, while ...Multivariate analysis and filtering techniques are widely applied to simultaneous and/or selective determination of multicomponent systems. Many methods among them are based on the principle of linear addition, while this principle does not always hold due to various physical and chemical factors. Using quite a different way, neural network (NN) based on a given learning rule, such as back propagation (BP) model, needs neither knowing nor using any form of input/output relationship. Particularly, NN can resolve various problems such as those with casual relation, those with fuzzy backgrounds, and those with uncertain inferential processes. NN was used by us to investigate quantitative struc-展开更多
The conformational transition of a new glycoconjugate, tea glycoconjugate (TGC), was investigated by spec-troscopy techniques including circular dichroism (CD) and ultraviolet (UV) spectroscopy. The solution behaviors...The conformational transition of a new glycoconjugate, tea glycoconjugate (TGC), was investigated by spec-troscopy techniques including circular dichroism (CD) and ultraviolet (UV) spectroscopy. The solution behaviors of TGC in the mediums of different temperature, pH value, and ions were compared. Results showed that the native conformation of TGC was partially ordered. The CD value and UV absorbance of TGC altered with the change of pH value, temperature, the addition of ions, and also accompanied order-disorder transition. Especially the condi-tions with temperature higher than the glass transition temperature (Tg=62 ℃), higher pH value or lower pH value will have the most impact on the conformation of TGC, which will destroy the hydrogen bonds between the TGC molecules. The results indicated that the outside factors play important roles on the stability of the conformation of TGC.展开更多
In this paper a quick method was developed to determine separate furfural and HMF concentrations simultaneously in ethanol-water hydrolysate of reed based on UV spectroscopy.Acid soluble lignin and other interfering s...In this paper a quick method was developed to determine separate furfural and HMF concentrations simultaneously in ethanol-water hydrolysate of reed based on UV spectroscopy.Acid soluble lignin and other interfering substances were first removed by distillation as residue.The distillate was then used for the determination of furfural and HMF by measuring the maximum absorption wavelength and the absorbance at the wavelength.Results showed that the maximum absorption wavelength of the characteristic peak correlated well with the composition of furfural and HMF mixture in an ethanol-water solution,and the absorbance at the maximum absorption wavelength also had an excellent linear relationship with the sum concentration of furfural and HMF in the solution.The separate concentrations of furfural and HMF in a mixture solution could be determined by applying these correlations.展开更多
The optical absorption edge and ultraviolet (UV) emission energy of ZnO films deposited by direct current (DC) reactive magnetron sputtering at room temperature have been investigated. With the oxygen ratio increasing...The optical absorption edge and ultraviolet (UV) emission energy of ZnO films deposited by direct current (DC) reactive magnetron sputtering at room temperature have been investigated. With the oxygen ratio increasing, the structure of films changes from zinc and zinc oxide coexisting phase to single-phase ZnO and finally to the highly (002) orientation. Both the grain size and the stress of ZnO film vary with the oxygen partial pressure. Upon increasing the oxygen partial pressure in the growing ambient, the visible emission in the room-temperature photoluminescence spectra was suppressed without sacrificing the band- edge emission intensity in the ultraviolet region. The peaks of photoluminescence spectra were located at 3.06—3.15 eV. Prom optical transmittance spectra of ZnO films, the optical band gap edge was observed to shift towards shorter wavelength with the increase of oxygen partial pressure.展开更多
B2Oa-P2O5-SiO2 (BPS) three-dimensional (3D) high-organized polystyrene (PS) opals and inverse opals with large domain were fabricated and characterized. Scanning electron microscope (SEM) shows three or four s...B2Oa-P2O5-SiO2 (BPS) three-dimensional (3D) high-organized polystyrene (PS) opals and inverse opals with large domain were fabricated and characterized. Scanning electron microscope (SEM) shows three or four small "windows", indicating that a very well interconnection between PS spheres of opal. The ultraviolet-visible (UV-vis) spectra indicate that the photonic band gaps (PBGs) are about 710 and 604 nm for 320- and 270-nm spheres respectively. While according to Bragg's equation, the simulation results should be 762 and 643 nm, which mean that 52 and 39 nm were shifted to blue region, respectively.展开更多
A self-organized thin film of a cyanine dye is fabricated by the spin-coating technique and is characterized by ultraviolet-visible spectroscopy, infrared (IR) spectroscopy, small-angle X-ray diffraction, eUipsomete...A self-organized thin film of a cyanine dye is fabricated by the spin-coating technique and is characterized by ultraviolet-visible spectroscopy, infrared (IR) spectroscopy, small-angle X-ray diffraction, eUipsometer, and atomic force microscopy (AFM). The nonlinear optical properties of the thin films are investigated by degenerate four wave mixing (DFWM) technique. The cyanine dye thin film sample exhibits high optical nonlinearities (χ^(3) = 2.55 × 10^-12 esu), and the mechanism is analyzed by the exciton coupling theory.展开更多
Genotoxicity in wastewater and reclaimed water now is gaining increased attention because of genotoxins' potential damage to the ecosystem and human health. The effect of ozonation on genotoxicity in reclaimed water ...Genotoxicity in wastewater and reclaimed water now is gaining increased attention because of genotoxins' potential damage to the ecosystem and human health. The effect of ozonation on genotoxicity in reclaimed water was investigated. It was found that ozonation decreased the genotoxicy dramatically in three tertiary treatment plants. In the further batch ozonation experiment in laboratory, secondary effluent sample used exhibited the genotoxicity of (41.1 ± 4.1) μg 4NQO/L. Ozonation with a dose of 10 mg O3/L completely removed the genotoxicity in secondary effluent. However, after ozonation, the dissolved organic carbonvalue of the sample didn't change much but the specific ultraviolet absorbance (SUVA) value dropped sharply. With the help of Fourier transform infrared spectroscopy, ozonation was found to change chemical aliphatic carbon and C-O of the dissolved arganic matter, which might be the reason of the significant decreases of SUVA and genotoxicity.展开更多
A light purplish red sapphire is heat treated in an airtight crucible. The sample changes little in color after receiving heat treatment at 1100℃, but turns to light blue and blue after being treated at 1200℃ and 1...A light purplish red sapphire is heat treated in an airtight crucible. The sample changes little in color after receiving heat treatment at 1100℃, but turns to light blue and blue after being treated at 1200℃ and 1300℃, respectively. Before heating, the UV-VIS absorption spectra of the sample are dominated by the 551 nm broad absorption band contributed by the d-electron transition 4A2 →4 4T2 of Cr3+. After heating, the UV-VIS absorption spectra are dominated by the 563 nm broad absorption band contributed by the inter- valence charge transfer of Fe2+ - Ti4+. The x ray photoelectron spectroscopy test reveals that the Fe2+ and Ti4+ ion contents increase with increasing temperature. The sapphire changing from light purplish red to blue in the heating process is owing to the fact that the Fe2+ and Ti4+ contents grow and the intervalence charge transfer of Fe2+ - Ti4+ selectively absorbs UV-VIS light.展开更多
Experimental determination of density, ultrasonic velocity and viscosity of two pyrimidine bases thymine and cytosine along with their respective nucleosides, thymidine and cytidine has been carried out in aqueous ure...Experimental determination of density, ultrasonic velocity and viscosity of two pyrimidine bases thymine and cytosine along with their respective nucleosides, thymidine and cytidine has been carried out in aqueous urea solutions in the presence of different concentrations of three salts, viz. NaC1, KCl and CaCl2. The experimental data have been used for the computation of various thermodynamic parameters, viz. apparent molar volume, apparent molar compressibility, coefficients A and B of the Jones-Dole equation, internal pressure, acoustic impedance, etc. Structural studies of solutions under investigation have also been carried out by ultraviolet spectroscopy, and an at- tempt has been made to collaborate the findings of ultraviolet spectroscopy with results obtained thermodynami- cally.展开更多
The interaction of Co(Ⅱ) with BSA under UV C (253.7 nm) irradiation under physiological conditions has been studied by UV-vis spectrum, ultraviolet second-derivative spectroscopy and fluorescence spectrum. The qu...The interaction of Co(Ⅱ) with BSA under UV C (253.7 nm) irradiation under physiological conditions has been studied by UV-vis spectrum, ultraviolet second-derivative spectroscopy and fluorescence spectrum. The quenching rate constant kq and the association constant Ka were calculated according to Stern-Volmer equation based on the quenching of the fluorescence of BSA by Co(Ⅱ).展开更多
基金partially supported by National Natural Science Foundation of China(Nos.U23A2077,12175278,12205072)the National Magnetic Confinement Fusion Science Program of China(Nos.2019YFE0304002,2018YFE0303103)+2 种基金the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)Major Science and Technology Infrastructure Maintenance and Reconstruction Projects of the Chinese Academy of Sciences(2021)the University Synergy Innovation Program of Anhui Province(No.GXXT2021-029)。
文摘A vacuum ultraviolet(VUV)spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced Superconducting Tokamak(EAST).In this study,wavelength calibration for the VUV spectroscopy is achieved utilizing a zinc lamp.The grating angle and charge-coupled device(CCD)position are carefully calibrated for different wavelength positions.The wavelength calibration of the VUV spectroscopy is crucial for improving the accuracy of impurity spectral data,and is required to identify more impurity spectral lines for impurity transport research.Impurity spectra of EAST plasmas have also been obtained in the wavelength range of 50–300 nm with relatively high spectral resolution.It is found that the impurity emissions in the edge region are still dominated by low-Z impurities,such as carbon,oxygen,and nitrogen,albeit with the application of fulltungsten divertors on the EAST tokamak.
文摘In this paper,an absorption spectroscopy measurement method was applied on two atmospheric pressure plasma sources to determine their production of nitric oxide.The concentrations are essential for evaluating the plasma sources based on the principle of the Dielectric Barrier Discharge(DBD)for applications in plasma medicine.The described method is based on a setup with an electrodeless discharge lamp filled with a mixture of oxygen and nitrogen.One of the emitted wavelengths is an important resonance wavelength of nitric oxide(λ = 226.2 nm).By comparing the absorption behaviour at the minimum and maximum of the spectral absorption cross section of nitric oxide around that wavelength,and measuring the change in intensity by the absorbing plasma,the concentration of nitric oxide inside the plasma can be calculated.The produced nitric oxide concentrations depend on the pulse duration and are in the range of 180 ppm to 1400 ppm,so that a distance of about 10 cm to the respiratory tract is enough to conform to the VDI Guideline 2310.
文摘Methanol/TiO2(110) is a model system in the surface science study of photocatalysis where methanol is taken as a hole capture. However, the highest occupied molecular orbital of adsorbed methanol lies below the valence band maximum of TiO2, preventing the hole transfer. To study the level alignment of this system, electronic structure of methanol covered TiO2(110) surface has been measured by ultraviolet photoelectron spectroscopy and the molecular orbitals of adsorbed methanol have been clearly identified. The results indicate the weak interaction between methanol and TiO2 substrate. The static electronic structure also suggests the mismatch of the energy levels. These static experiments have been performed without band gap excitation which is the prerequisite of a photocatalytie process. Future study of the transient electronic structure using time-resolved UPS has also been discussed.
基金This work is financially supported by the Natural Science Foundation of Shandong Province, China (No. Y2005B10).
文摘Single crystalline ZnO nanorods were prepared by the hydrothermal method with synthesized ZnCl2·4Zn(OH)2 as the precursor. Morphologies of the nanorods were controlled by various reaction conditions with cetyltrimethylammonium bromide (CTAB) as the modifying agent. The nanorods were characterized by XRD, TEM, UV-Vis spectra, and IR spectra. The microstructure of holes in nanosize was observed on the surface of the nanorods. The UV-Vis spectra indicate that the as-prepared ZnO nanorods have absorption of visible-hght as well as ultraviolet-light. Therefore, these nanorods may be good candidates for visible-light photocatalysis materials from the viewpoint of practical applications. The reason for visible-light absorption was discussed in this article.
文摘Semiconductors are a major category of functional materials essential to various applications to sustain the modern society.Most applied materials or devices utilizing semiconductors are enabled by interfaces or junctions,such as solar cells,electronic/photonic devices,environmental sensors,and redox hetero-catalysts.Herein,the author provides a critical commentary on photoemission measurement of the work function and,more importantly,the electron affinity of semiconductors essential for energy band diagram of heterojunctions.Particular effort is made towards addressing complications associated with Fermi level pinning due to surficial states of doped semiconductors.
基金supported by the National Natural Science Foundation of China (21703221, 21473166)Hefei Science Center CAS (2016HSC-IU012)
文摘Two-dimensional ultraviolet(2 DUV) spectroscopy is a novel technology for probing molecular structure. We have developed a generalized quantum mechanics/molecular mechanics(QM/MM) approach to simulate the electronic transitions of protein backbones and aromatic amino acids in aqueous solution. These transitions, which occur in the ultraviolet(UV) region, provide a sensitive probe of molecular structure. The features of 2 DUV spectra are accurately characterized and enable us to trace small variations in the structure and dynamics as well as evolution propensity with high accuracy. Various structures and dynamic phenomena are investigated to construct a systematic framework for 2 DUV simulation mechanisms, so as to explore further applications of this technique. In this feature article, we summarize the theory and applications of 2 DUV spectroscopy we have engaged in recently, present the important roles of 2 DUV spectroscopy, and outline directions for future development. We hope this article can offer a platform for more scientists in different research fields to gain a clear overview of 2 DUVand further attract more people to explore this promising field.
文摘Some new complexes RE2(EDODA)3·3H2O, where RE = La, Nd, Eu, Gd, Tb, Er, Yb, Lu and Y, EDODA = ethylene-1,2-dioxydiacetate, have been synthesized and characterized by elemental analysis, molar conductance, IR spectra, UV spectra, TG-DTA, 1H NMR and 13C NMR spectra. Various analyses indicate that the complexes are of nine-coordinated binuclear structure. The carboxylates are bidentate ligands and the ether oxygen atoms also coordinate to rare earth ions. Three water molecules are crystalline water. In addition, the influence of concentration on the chemical shift has been studied through the 1H NMR spectra of the complex Lu2(EDODA)3·3H2O in different concentrations.
基金support from the Research Council of Azarbaijan Shahid Madani University (ASMU,Iran)
文摘In this work, the nickel-aluminum layered double hydroxide (Ni-Al LDH) with nitrate interlayer anion was synthesized and used as a solid phase extraction sorbent for the selective separation and pre-concentration of mefenamic acid prior to quantification by UV detection at λmax ? 286 nm. Extraction procedure is based on the adsorption of mefenamate anions on the Ni-Al(NO3? ) LDH and/or their exchange with LDH interlayer NO3? anions. The effects of several parameters such as cations and interlayer anions type in LDH structure, pH, sample flow rate, elution conditions, amount of nano-sorbent and co-existing ions on the extraction were investigated and optimized. Under the optimum conditions, the calibration graph was linear within the range of 2-1000 mg/L with a correlation coefficient of 0.9995. The limit of detection and relative standard deviation were 0.6 mg/L and 0.84% (30 mg/L, n ? 6), respectively. The presented method was successfully applied to determine of mefenamic acid in human serum and pharmaceutical wastewater samples.
基金supported by the National Research Foundation (NRF) of Korea (Nos. 2018R1D1A1B07051429 and 2020R1G1A1102692)。
文摘Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF_(4)/Ar ratio of 50:50 sccm. Regardless of the ratio of CF_(4) to Ar,the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF-4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication.
基金Project supported by the Japanese Ministry of Education,CultureScience(Monbusho),the Ministry of Mechanical Industry of China(MMIC),the State Education Commission of China(SECC)the National Natural Science Foundation of China(NSFC).
文摘Multivariate analysis and filtering techniques are widely applied to simultaneous and/or selective determination of multicomponent systems. Many methods among them are based on the principle of linear addition, while this principle does not always hold due to various physical and chemical factors. Using quite a different way, neural network (NN) based on a given learning rule, such as back propagation (BP) model, needs neither knowing nor using any form of input/output relationship. Particularly, NN can resolve various problems such as those with casual relation, those with fuzzy backgrounds, and those with uncertain inferential processes. NN was used by us to investigate quantitative struc-
基金Project supported by the National Natural Science Foundation of China (No. 30270939).
文摘The conformational transition of a new glycoconjugate, tea glycoconjugate (TGC), was investigated by spec-troscopy techniques including circular dichroism (CD) and ultraviolet (UV) spectroscopy. The solution behaviors of TGC in the mediums of different temperature, pH value, and ions were compared. Results showed that the native conformation of TGC was partially ordered. The CD value and UV absorbance of TGC altered with the change of pH value, temperature, the addition of ions, and also accompanied order-disorder transition. Especially the condi-tions with temperature higher than the glass transition temperature (Tg=62 ℃), higher pH value or lower pH value will have the most impact on the conformation of TGC, which will destroy the hydrogen bonds between the TGC molecules. The results indicated that the outside factors play important roles on the stability of the conformation of TGC.
基金National Natural Science Foundation of China for financial support for this research (Grant#:31270634).
文摘In this paper a quick method was developed to determine separate furfural and HMF concentrations simultaneously in ethanol-water hydrolysate of reed based on UV spectroscopy.Acid soluble lignin and other interfering substances were first removed by distillation as residue.The distillate was then used for the determination of furfural and HMF by measuring the maximum absorption wavelength and the absorbance at the wavelength.Results showed that the maximum absorption wavelength of the characteristic peak correlated well with the composition of furfural and HMF mixture in an ethanol-water solution,and the absorbance at the maximum absorption wavelength also had an excellent linear relationship with the sum concentration of furfural and HMF in the solution.The separate concentrations of furfural and HMF in a mixture solution could be determined by applying these correlations.
文摘The optical absorption edge and ultraviolet (UV) emission energy of ZnO films deposited by direct current (DC) reactive magnetron sputtering at room temperature have been investigated. With the oxygen ratio increasing, the structure of films changes from zinc and zinc oxide coexisting phase to single-phase ZnO and finally to the highly (002) orientation. Both the grain size and the stress of ZnO film vary with the oxygen partial pressure. Upon increasing the oxygen partial pressure in the growing ambient, the visible emission in the room-temperature photoluminescence spectra was suppressed without sacrificing the band- edge emission intensity in the ultraviolet region. The peaks of photoluminescence spectra were located at 3.06—3.15 eV. Prom optical transmittance spectra of ZnO films, the optical band gap edge was observed to shift towards shorter wavelength with the increase of oxygen partial pressure.
基金This work was supported by the National Science Foundation of China (No.50502007)the Opening Foundation of Beijing Key Laboratory,Beijing University of Science and Technology.
文摘B2Oa-P2O5-SiO2 (BPS) three-dimensional (3D) high-organized polystyrene (PS) opals and inverse opals with large domain were fabricated and characterized. Scanning electron microscope (SEM) shows three or four small "windows", indicating that a very well interconnection between PS spheres of opal. The ultraviolet-visible (UV-vis) spectra indicate that the photonic band gaps (PBGs) are about 710 and 604 nm for 320- and 270-nm spheres respectively. While according to Bragg's equation, the simulation results should be 762 and 643 nm, which mean that 52 and 39 nm were shifted to blue region, respectively.
基金This work was supported by the National Natural Science Foundation of China(No.10574046)the National Key Project for Basic Research of China(No.2006CB806006 and 2006CB921105)+4 种基金the Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT)the Program for New Century Excellent Talents in University(NCET-04-0420)the Doctoral Program of High Education(No.20050269011)the Phosphor Program sponsored by Shanghai Science Technology Committee(No. 06QH14003)the Twilight Project sponsored by Shanghai Education Committee(No.03SG23).
文摘A self-organized thin film of a cyanine dye is fabricated by the spin-coating technique and is characterized by ultraviolet-visible spectroscopy, infrared (IR) spectroscopy, small-angle X-ray diffraction, eUipsometer, and atomic force microscopy (AFM). The nonlinear optical properties of the thin films are investigated by degenerate four wave mixing (DFWM) technique. The cyanine dye thin film sample exhibits high optical nonlinearities (χ^(3) = 2.55 × 10^-12 esu), and the mechanism is analyzed by the exciton coupling theory.
基金supported by the National Natural Science Foundation of China (No. 51138006)the National HighTech Research and Development Program (863) of China (No. SS2013AA061805)+1 种基金the Ministry of Environmental Protection of China (No. 201109015)the Collaborative Innovation Center for Regional Environmental Quality
文摘Genotoxicity in wastewater and reclaimed water now is gaining increased attention because of genotoxins' potential damage to the ecosystem and human health. The effect of ozonation on genotoxicity in reclaimed water was investigated. It was found that ozonation decreased the genotoxicy dramatically in three tertiary treatment plants. In the further batch ozonation experiment in laboratory, secondary effluent sample used exhibited the genotoxicity of (41.1 ± 4.1) μg 4NQO/L. Ozonation with a dose of 10 mg O3/L completely removed the genotoxicity in secondary effluent. However, after ozonation, the dissolved organic carbonvalue of the sample didn't change much but the specific ultraviolet absorbance (SUVA) value dropped sharply. With the help of Fourier transform infrared spectroscopy, ozonation was found to change chemical aliphatic carbon and C-O of the dissolved arganic matter, which might be the reason of the significant decreases of SUVA and genotoxicity.
文摘A light purplish red sapphire is heat treated in an airtight crucible. The sample changes little in color after receiving heat treatment at 1100℃, but turns to light blue and blue after being treated at 1200℃ and 1300℃, respectively. Before heating, the UV-VIS absorption spectra of the sample are dominated by the 551 nm broad absorption band contributed by the d-electron transition 4A2 →4 4T2 of Cr3+. After heating, the UV-VIS absorption spectra are dominated by the 563 nm broad absorption band contributed by the inter- valence charge transfer of Fe2+ - Ti4+. The x ray photoelectron spectroscopy test reveals that the Fe2+ and Ti4+ ion contents increase with increasing temperature. The sapphire changing from light purplish red to blue in the heating process is owing to the fact that the Fe2+ and Ti4+ contents grow and the intervalence charge transfer of Fe2+ - Ti4+ selectively absorbs UV-VIS light.
文摘Experimental determination of density, ultrasonic velocity and viscosity of two pyrimidine bases thymine and cytosine along with their respective nucleosides, thymidine and cytidine has been carried out in aqueous urea solutions in the presence of different concentrations of three salts, viz. NaC1, KCl and CaCl2. The experimental data have been used for the computation of various thermodynamic parameters, viz. apparent molar volume, apparent molar compressibility, coefficients A and B of the Jones-Dole equation, internal pressure, acoustic impedance, etc. Structural studies of solutions under investigation have also been carried out by ultraviolet spectroscopy, and an at- tempt has been made to collaborate the findings of ultraviolet spectroscopy with results obtained thermodynami- cally.
基金Project supported by the National Natural Science Foundation of China (No. 20671023), the Science Foundation of Guangxi Province, China, and the Teaching and Research Award Programme for 0utstanding Young Teachers in Higher Education Institutions of Ministry of Education, China.
文摘The interaction of Co(Ⅱ) with BSA under UV C (253.7 nm) irradiation under physiological conditions has been studied by UV-vis spectrum, ultraviolet second-derivative spectroscopy and fluorescence spectrum. The quenching rate constant kq and the association constant Ka were calculated according to Stern-Volmer equation based on the quenching of the fluorescence of BSA by Co(Ⅱ).