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Numerical studies of surface and bulk modes in attenuated total reflection spectra 被引量:1
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作者 燕保荣 吕建红 +1 位作者 孔令华 胡希伟 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期444-452,共9页
The dispersion relations of normal modes in the layered constructions are studied. In the frequency region with negative permittivity, we investigate the normal modes near the air-metal and the air-matematerial interf... The dispersion relations of normal modes in the layered constructions are studied. In the frequency region with negative permittivity, we investigate the normal modes near the air-metal and the air-matematerial interfaces and compare them. An extra bulk mode appearing in a pass band of two media is found near the air-matematerial interface, which is different from the air-metal case. Moreover, the bulk mode will be further proved by the attenuated total reflection (ATR) technique, in which the coupling between the incident electromagnetic waves and the normal modes is studied. For p-polarized incident waves, the ATR spectra based on the Otto and the Kretschmann configurations are obtained numerically, where the dips present the excitations of the surface and bulk modes. Furthermore, we also discuss the influences of the middle layer thickness, the incident angle and the damping term on the reflection in detail. It is found that the coupling frequencies and the maximum strength are strongly dependent on the above media parameters. 展开更多
关键词 surface polaritons attenuated total reflection METAMATERIAL
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Process Characterization of the Transesterification of Rapeseed Oil to Biodiesel Using Design of Experiments and Infrared Spectroscopy
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作者 Tobias Drieschner Andreas Kandelbauer +1 位作者 Bernd Hitzmann Karsten Rebner 《Journal of Renewable Materials》 SCIE EI 2023年第4期1643-1660,共18页
For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the proc... For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process. 展开更多
关键词 Process analytical technology TRANSESTERIFICATION design of experiment attenuated total reflection infrared spectroscopy partial least square regression
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Possible Relevance of the Allende Meteorite Conditions in Prebiotic Chemistry: An Insight into the Chondrules and Organic Compounds
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作者 Alejandro Heredia Barbero Héctor G. Vázquez López +8 位作者 Adriana L. Meléndez López Jorge A. Cruz Castañeda Daniel Luna Laviada Karina E. Cervantes de la Cruz Victor Meza Laguna Vladimir A. Basiuk Ivonne Rosales Chávez Alicia Negrón Mendoza Sergio Ramos Bernal 《Advances in Biological Chemistry》 2023年第3期82-99,共18页
The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the... The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the magnetic minerals present in ordinary and carbonaceous chondrites, providing information on the evolution of magnetic fields. The interaction of organic compounds with magnetic minerals is a possible source of chemical diversity, which is crucial for molecular evolution. Carbon compounds in meteorites are of great scientific interest for a variety of reasons, such as their relevance to the origins of chirality in living organisms. This study presents the characterization of organic and mineral compounds in the Allende meteorite. The structural and physicochemical characterization of the Allende meteorite was accomplished through light microscopy, powder X-ray diffraction with complementary Rietveld refinement, Raman and infrared spectroscopy, mass spectrometry, scanning electron microscopy, and atomic force microscopy using magnetic signal methods to determine the complex structure and the interaction of organic compounds with magnetic Ni-Fe minerals. The presence of Liesegang-like patterns of chondrules in fragments of the Allende structure may also be relevant to understanding how the meteorite was formed. Other observations include the presence of magnetic materials and nanorod-like solids with relatively similar sizes as well as the heterogeneous distribution of carbon in chondrules. Signals observed in the Raman and infrared spectra resemble organic compounds such as carbon nanotubes and peptide-like molecules that have been previously reported in other meteorites, making the Mexican Allende meteorite a feasible sample for the study of the early Earth and exoplanetary bodies. 展开更多
关键词 Allende Meteorite Carbonaceous Chondrite Light Microscopy X-Ray Diffraction with the Rietveld Method Raman Spectroscopy Attenuated Total Reflectance Infrared Spectroscopy Mass Spectrometry Scanning Electron Mi-croscopy Energy Dispersive X-Ray Spectroscopy Magnetic Force Microscopy
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Role of Bridge-bonded Formate in Formic Acid Dehydration to CO at Pt Electrode: Electrochemial in-situ Infrared Spectroscopic Study 被引量:1
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作者 张尊彪 徐杰 +1 位作者 康婧 陈艳霞 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第4期471-476,J0002,共7页
Formic acid (HCOOH) decomposition at Pt film electrode has been studied by electrochem- ical in situ FTIR spectroscopy under attenuated-total-reflection configuration, in order to clarify whether bridge-bonded forma... Formic acid (HCOOH) decomposition at Pt film electrode has been studied by electrochem- ical in situ FTIR spectroscopy under attenuated-total-reflection configuration, in order to clarify whether bridge-bonded formate (HCOOD) is the reactive intermediate for COad for-mation from HCOOH molecules. When switching from HCOOH-free solution to HCOOH- containing solution at constant potential (E=0.4 V vs. RHE), we found that immediately upon solution switch COad formation rate is the highest, while surface coverage of formate is zero, then after COad formation rate decreases, while formate coverage reaches a steady state coverage quickly within ca. 1 s. Potential step experiment from E=0.75 V to 0.35 V, reveals that formate band intensity drops immediately right after the potential step, while the COad signal develops slowly with time. Both facts indicate that formate is not the reactive intermediate for formic acid dehydration to CO. 展开更多
关键词 Mechanism for formic acid dehydration Formate intermediate CO pathway Pt electrode Infrared spectroscopic studies under attenuated total reflection configuration
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LESS-INVASIVE LASER THERAPY AND DIAGNOSIS USING A TABLETOP MID-INFRARED TUNABLE LASER 被引量:1
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作者 HISANAO HAZAMA KATSUNORI ISHII KUNIO AWAZU 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2010年第4期285-292,共8页
Since numerous characteristic absorption lines caused by molecular vibration exist in the midinfrared(MIR)wavelength region,selective excitation or selective dissociation of molecules is possible by tuning the laser w... Since numerous characteristic absorption lines caused by molecular vibration exist in the midinfrared(MIR)wavelength region,selective excitation or selective dissociation of molecules is possible by tuning the laser wavelength to the characteristic absorption lines of target molecules.By applying this feature to the medical fields,less-invasive treatment and non-destructive diagnosis with absorption spectroscopy are possible using tunable MIR lasers.A high-energy nanosecond pulsed MIR tunable laser was obtained with difference-frequency generation(DFG)between a Nd:YAG and a tunable Cr:forsterite lasers.The MIR-DFG laser was tunable in a wavelength range of 5.5–10μm and generated laser pulses with energy of up to 1.4mJ,a pulse width of 5 ns,and a pulse repetition rate of 10 Hz.Selective removal of atherosclerotic lesion was successfully demonstrated with the MIR-DFG laser tuned at a wavelength of 5.75μm,which corresponds to the characteristic absorption of the ester bond in cholesterol esters in the atherosclerotic lesions.We have developed a non-destructive diagnostic probe with an attenuated total reflection(ATR)prism and two hollow optical fibers.An absorption spectrum of cholesterol was measured with the ATR probe by scanning the wavelength of the MIR-DFG laser,and the spectrum was in good agreement with that measured with a commercial Fourier transform infrared spectrometer. 展开更多
关键词 Mid-infrared tunable laser difference-frequency generation selective treatment attenuated total reflection spectroscopy hollow optical fiber
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Surface plasmon polaritons of symmetric and asymmetric metamaterial slabs
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作者 张惠芳 曹迪 +4 位作者 陶峰 杨希华 王燕 阎晓娜 白丽华 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第2期439-449,共11页
The p and s-polarized surface plasmon polaritons (SPPs) of symmetric and asymmetric slabs formed arbitrarily by four types of conventional materials: dielectrics, negative dielectric permittivity materials, negativ... The p and s-polarized surface plasmon polaritons (SPPs) of symmetric and asymmetric slabs formed arbitrarily by four types of conventional materials: dielectrics, negative dielectric permittivity materials, negative magnetic permeability materials, and left-handed materials are comprehensively analysed. The existence regions, dispersion relations, and excitation of SPPs in different frequency regions are investigated in detail. For symmetric slabs, the numbers and the frequency positions of surface polariton branches are quite different. At the same time, the pairs of the p or s-polarized SPP branches occur in the same frequency range. For asymmetric slabs, the SPP branches in mid- and high-frequency ranges are greatly different. In addition, the slab thickness has a great effect on SPPs of asymmetric and symmetric slabs. The attenuated total reflection spectra for the cases of p and s polarizations in these slabs are also calculated. 展开更多
关键词 surface plasmon polaritons META-MATERIALS symmetric and asymmetric slabs attenuated total reflection technique
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Deliquescence and Efflorescence Processes of Aerosol Particles Studied by in situ FTIR and Raman Spectroscopy
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作者 Li-jun Zhao Feng Wang +2 位作者 Kun Zhang Qing-xuan Zeng Yun-hong Zhang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2008年第1期1-11,共11页
Deliquescence and efflorescence are the two most important physicochemical processes of aerosol particles. In deliquescence and efflorescence cycles of aerosol particles, many fundamental problems need to be investiga... Deliquescence and efflorescence are the two most important physicochemical processes of aerosol particles. In deliquescence and efflorescence cycles of aerosol particles, many fundamental problems need to be investigated in detail on the molecular level, including ion and molecule interactions in supersaturated aerosols, metastable solid phases that may be formed, and microscopic structures and deliquescence mechanisms of aerosol particles. This paper presents a summary of the progress made in recent investigations of deliquescence and efflorescence processes of aerosol particles by four common spectral techniques, which are known as Raman/electrodynamic balance, Fourier transform infrared/aerosol flow tube, Fourier transform infrared/attenuated total reftection, and confocal Raman on a quartz substrate. 展开更多
关键词 AEROSOL DELIQUESCENCE EFFLORESCENCE Raman/electrodynamic balance Fourier transform infrared/aerosol flow tube Fourier transform infrared/attenuated total reflection Confocal Raman
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Responses of Transmembrane Peptide and Lipid Chains to Hydrophobic Mismatch
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作者 YANG Lei LI Jian-tao +1 位作者 QI Hai-yan LI Fei 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第4期732-736,共5页
Hydrophobic mismatch between the hydrophobic length of membrane proteins and hydrophobic thickness of membranes is a crucial factor in controlling protein function and assembly.We combined fluorescence with circular d... Hydrophobic mismatch between the hydrophobic length of membrane proteins and hydrophobic thickness of membranes is a crucial factor in controlling protein function and assembly.We combined fluorescence with circular dichroism(CD) and attenuated total reflection infrared(ATR-IR) spectroscopic methods to investigate the behaviors of the peptide and lipids under hydrophobic mismatch using a model peptide from the fourth transmembrane domain of natural resistance-associated macrophage protein 1(Nramp1),the phosphatidylcholines(PCs) and phosphatidylglycerols(PGs) with different lengths of acyl chains(14:0,16:0 and 18:0).In all PG lipid membranes,the peptide forms stable α-helix structure,and the helix axis is parallel to lipid chains.The helical span and orientation hardly change in varying thickness of PG membranes,while the lipid chains can deform to accommodate to the hydrophobic surface of embedded peptide.By comparison,the helical structures of the model peptide in PC lipid membranes are less stable.Upon incorporation with PC lipid membranes,the peptide can deform itself to accommodate to the hydrophobic thickness of lipid membranes in response to hydrophobic mismatch.In addition,hydrophobic mismatch can increase the aggregation propensity of the peptide in both PC and PG lipid membranes and the peptide in PC membranes has more aggregation tendency than that in PG membranes. 展开更多
关键词 Hydrophobic mismatch Transmembrane peptide Fluorescence Circular dichroism(CD) Attenuated total reflection infrared(ATR-IR)
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Electrochemical CO2 Reduction on Pd-Modified Cu Foil
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作者 Zhi-juan Sun Matthew M.Sartiny +5 位作者 Wei Chen Fan He Jun Cai Xu-xu Ye Jun-ling Lu Yan-xia Chen 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第3期303-310,I0002,共9页
Bimetallic catalysts can improve CO2 reduction efficiency via the combined properties of two metals.CuPd shows enhanced CO2 reduction activity compared to copper alone.Using differential electrochemical mass spectrome... Bimetallic catalysts can improve CO2 reduction efficiency via the combined properties of two metals.CuPd shows enhanced CO2 reduction activity compared to copper alone.Using differential electrochemical mass spectrometry(DEMS)and electrochemical infrared(IR)spectroscopy,volatile products and adsorbed intermediates were measured during CO2 and CO reduction on Cu and CuPd.The IR band corresponding to adsorbed CO appears 300 mV more positive on CuPd than that on Cu,indicating acceleration of CO2 reduction to CO.Electrochemical IR spectroscopy measurements in CO-saturated solutions reveal similar potentials for CO adsorption and CO3^2-desorption on CuPd and Cu,indicating that CO adsorption is controlled by desorption of CO3^2-.DEMS measurements carried out during CO reduction at both electrodes showed that the onset potential for reduction of CO to CH4 and CH3OH on CuPd is about 200 mV more positive than that on Cu.We attribute these improvements to interaction of Cu and Pd,which shifts the d-band center of the Cu sites. 展开更多
关键词 CO2 reduction CH band CuPd activity Differential electrochemical mass spectrometry Attenuated total reflection Fourier transform infrared spectroscopy
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Connection of acoustic absorption, reflection lossesand mode attenuation in shallow water
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作者 JIANG Dejun(Institute Of Acoustics Beijing 100080) 《Chinese Journal of Acoustics》 1997年第4期312-321,共10页
The relationship among acoustic absorption in the water, the boundaries losses on the surface and bottom and mode attenuation per cycle is presented, using the method of complex effective depth approximation. The equi... The relationship among acoustic absorption in the water, the boundaries losses on the surface and bottom and mode attenuation per cycle is presented, using the method of complex effective depth approximation. The equivalence of bottom refiection loss and mode attenuation per cycle, based on the work of Tindle [J. Acoust. Soc. Am. 66, 250-255 (1979)],is proved to give rise to several deviation in the range of middle low frequency (200 Hz <f < 2 kHz). Some of the results are that (1) corresponding to the small grazing angle, mode attenuation per cycle distance is equal to the sum of boundaryls reflection losses and the transmission loss per cycle distance of the waveguide geometric ray, (2) the method of complex effective depth approximation can give mode attenuation coefficient an explicit physical interpretation, which is similar to ray-mode theory. 展开更多
关键词 MODE CYCLE reflection lossesand mode attenuation in shallow water Connection of acoustic absorption
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Graphene Sheets with Modified Surface by Sodium Lauryl Sulfate Surfactant for Biomedical Applications
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作者 Zhypargul Abdullaeva Zhazgul Kelgenbaeva +3 位作者 Tsushida Masayuki Megumi Hirano Shoji Nagaoka Tomohiro Shirosaki 《Graphene》 2016年第4期155-165,共11页
This work describes synthesis of graphene sheets with modified surface by sodium lauryl sulfate (SLS) surfactant using one-pot solvothermal reaction method. Effect of sodium lauryl sulfate surfactant amount on surface... This work describes synthesis of graphene sheets with modified surface by sodium lauryl sulfate (SLS) surfactant using one-pot solvothermal reaction method. Effect of sodium lauryl sulfate surfactant amount on surface modification level of graphene sheets was investigated. Ether (-S-OR- at 762 cm<sup>-1</sup> - 863 cm<sup>-1</sup>), thiocarbonyl (=C=S at 1050 cm<sup>-1</sup> - 1176 cm<sup>-1</sup>) and sulfoxide (S-O, V<sub>s</sub> and V<sub>as</sub> at 1030 cm<sup>-1</sup> - 1450 cm<sup>-1</sup>) functional groups released from sodium lauryl sulfate (SLS) surfactant during solvothermal reaction and attached on the surface of graphene sheets were detected by (attenuated total reflectance-fast Fourier infrared) ATR-FTIR spectroscopy. (Atomic force microscope) AFM observations revealed apparent surface of graphene sheets modified by surfactant molecules with an average multiple profile of graphene nanosheets ≈ 4.8 nm high. This synthesis way of surface modified graphene sheets can be considered as easy, one-step and cheap method for manufacturing of novel biosurface with graphene, as reinforcement for biopolymer coatings such as ultra-high molecular weight polypropylene (UHMWPE), metallic biomaterials (Ti and Ti alloys) and bioceramics as hydroxyapatite (HA). 展开更多
关键词 GRAPHENE SYNTHESIS Surface Modification SURFACTANT Attenuated Total reflection
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Cu/Mo2C synthesized through Anderson-type polyoxometalates modulate interfacial water structure to achieve hydrogen evolution at high current density
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作者 Dunyuan Jin Fen Qiao +6 位作者 Yan Zhou Junfeng Wang Kecheng Cao Jing Yang Jikang Zhao Lei Zhou Haitao Li 《Nano Research》 SCIE EI CSCD 2024年第4期2546-2554,共9页
The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C... The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C)using Anderson-type polyoxometalates(POMs)synthesized by the facile soaking method as precursors.The electronic interaction between Cu and Mo_(2)C drives the positive charge of Cu,alleviating the strong adsorption of hydrogen at the Mo site by modulating the d-band center of Mo_(2)C.By studying the interfacial water structure using in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS),we determined that the positively charged Cu crystals have the function of activating water molecules and optimizing the interfacial water structure.The interfacial water of Cu/Mo_(2)C contains a large amount of free water,which could facilitate the transport of reaction intermediates.Due to activated water molecules and optimized interfacial water structure and hydrogen adsorption energy,the overpotential of Cu/Mo_(2)C is 24 mV at a current density of 10 mA·cm^(-2) and 178 mV at a current density of 1000 mA·cm^(-2).This work improves catalyst performance in terms of interfacial water structure optimization and deepens the understanding of water-mediated catalysis. 展开更多
关键词 electrocatalytic hydrogen production interfacial water charge transport d band center in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS)
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Ni-Cu bimetallic alloy anchored on nitrogen-doped carbon nanotubes for CO_(2)-to-CH_(4) electrochemical conversion
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作者 Jing Li Chuanyong Jing Jin Wang 《Nano Research》 SCIE EI CSCD 2024年第8期6922-6930,共9页
Electrocatalytic CO_(2) reduction to CH_(4) remains challenging due to multi-electron transfer and intermediates adsorption.Herein,we synthesized electrocatalysts by growing Ni-Cu alloy structure on nitrogen-doped car... Electrocatalytic CO_(2) reduction to CH_(4) remains challenging due to multi-electron transfer and intermediates adsorption.Herein,we synthesized electrocatalysts by growing Ni-Cu alloy structure on nitrogen-doped carbon nanotubes(NixCuy-NCNT)for electrocatalytic CO_(2) reduction reaction(CO_(2)RR)via hydrothermal method followed by pyrolysis.The optimized Ni_(1)Cu_(1)-NCNT demonstrated a superior CO_(2)RR performance,achieving 99.7%FECH_(4)(FE=Faradaic efficiency)and 11.54 mA·cm^(−2) current density at−1.2 V vs.reversible hydrogen electrode(RHE),which outperformed single metal counterparts.Its outstanding performance was due to the electrons transferred from Cu to Ni and Ni-Cu alloy shifted the d-band center toward the Fermi level,which was more conducive to the intermediate formation.In situ electrochemical attenuated total reflection(EC-ATR)and density functional theory(DFT)calculations revealed the appearance of *CHO intermediate and the pathway during the CO_(2)RR process.The design of the bimetallic electrocatalyst in this study provides a new perspective for the highly selective reduction of CO_(2). 展开更多
关键词 electrocatalytic CO_(2) reduction Ni-Cu alloy nitrogen-doped carbon nanotube(NCNT) electrochemical attenuated total reflection(EC-ATR) density functional theory(DFT)calculations
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Unraveling the interfacial effect of PdBi bimetallic catalysts on promoting CO_(2)electroreduction to formate
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作者 Wenhui Liu Lingtong Ding +5 位作者 Minmin Liu Xiao Wang Zhengrong Zhang Tian-Wen Jiang Shengjuan Huo Wen-Bin Cai 《Nano Research》 SCIE EI CSCD 2023年第8期10822-10831,共10页
Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEf... Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEformate)of 94%and a partial current density(jformate)of 34 mA·cm^(−2)at−0.8 V vs.reversible hydrogen electrode(RHE)in an H-cell.Moreover,the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm^(−2)with formate selectivity up to 92%in a flow cell and could steadily operate for at least 20 h.Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)confirmed that the PdBi interface could greatly weaken the adsorption of*CO intermediates due to electronic and geometric effects.Density functional theory(DFT)calculations also established that the PdBi interface regulated the CO_(2)-to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of*CO intermediates on the catalyst surface.This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations. 展开更多
关键词 carbon dioxide reduction reaction bimetallic PdBi interface engineering FORMATE in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)
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Experimental and mechanistic understanding of photo-oxidation of methanol catalyzed by CuO/TiO2-spindle nanocomposite:Oxygen vacancy engineering 被引量:8
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作者 Quanquan Shi Zhaoxian Qin +5 位作者 Changlin Yu Ammara Waheed Hui Xu Yong Gao Hadi Abroshan Gao Li 《Nano Research》 SCIE EI CAS CSCD 2020年第4期939-946,共8页
We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%s... We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%selectivity.The catalysts are obtained via precise depositing of CuO nanoclusters(size:~3.5 nm)at the{101}facet of the TiO2 to optimally tune exciton recombination through oxygen vacancies generation,evidenced by photoluminescence and Raman spectroscopy measurements.The turnover frequency(TOF)and the apparent quantum efficiency(AQE)of the 7%CuO/TiO2-spindle composites reach up to 23.8 molmethanol·gcat^-1·h^-1 and 55.2%at 25℃,respectively,which are substantially higher than these previously reported photocatalysts.Further,the in-situ attenuated total reflection infrared spectroscopy analysis reveals that the methanol oxidation most likely takes place through the conversion of adsorbed methoxy(CH30^*)to formaldehyde(CHO^*)intermediate,a subject of major debate for a long time.The adsorbed formaldehyde(CHO^*)thus produced reacts with another CH30^*species in its close proximity to form the final product of methyl formate.Results of this study provide insights into the reaction mechanism,and offer guidelines to systematically develop and apply photocatalysts for methanol conversion and related reactions via surface engineering. 展开更多
关键词 CuO/Ti02 nanocomposite methyl formate in-situ attenuated total reflection infrared spectroscopy photocatalysis oxygen vacancy METHANOL
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Performance measurement of sericin-coated silks during aging 被引量:4
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作者 ZHANG XiaoMei WYETH Paul 《Science China Chemistry》 SCIE EI CAS 2011年第6期1011-1016,共6页
Silks are among the most precious ancient and historic artefacts worldwide. While washing removes the natural gum from the fibres during the fabrication of most silk textiles, for a small proportion of historic silks ... Silks are among the most precious ancient and historic artefacts worldwide. While washing removes the natural gum from the fibres during the fabrication of most silk textiles, for a small proportion of historic silks some or perhaps all of the sericin still remains. This paper investigated the effect of sericin coating on the aging of silk fibroin by means of ATR and tensile testing. The results show that sericin can provide some extent of protection from light and heat aging. However, in high humidity environments degummed and ungummed silk aged at the same rate because of leaching of sericin. Silk degraded at faster rate and more extensively in a moist environment. ATR could give very useful information about the aging of silk. The ATR-derived crystallinity index is good at tracing the aging factor and extent of silk deterioration. Alanine and tyrosine within fibroin, as estimated by ATR spectroscopy, are very sensitive to light, but not to heat and water. The ATR absorbance intensity ratio Iamide Ⅲ/ Iamide I is very useful for deterioration evaluation of archaeological silk objects. As a high humidity resulted in the leaching of silk, it is suggested for sericin-coated silk in collections, that not only wet cleaning is harmful, but also that storage or display in a high RH environment would be detrimental. 展开更多
关键词 attenuated total reflectance infrared spectroscopy archaeological silk SERICIN
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Surface plasmon excitation in semitransparent inverted polymer photovoltaic devices and their applications as label-free optical sensors 被引量:2
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作者 Byoungchoo Park Soo Hong Yun +10 位作者 Chan Youn Cho Young Chan Kim Jung Chul Shin Hong Goo Jeon Yoon Ho Huh Inchan Hwang Ku Youn Baik Young In Lee Han Sup Uhm Guang Sup Cho Eun Ha Choi 《Light(Science & Applications)》 SCIE EI CAS 2014年第1期5-12,共8页
Herein,we report on surface plasmon(SP)-sensitive semitransparent inverted polymer photovoltaic(PV)devices that are based on multilayered material systems consisting of poly(3-hexylthiophene):fullerene-derivative bulk... Herein,we report on surface plasmon(SP)-sensitive semitransparent inverted polymer photovoltaic(PV)devices that are based on multilayered material systems consisting of poly(3-hexylthiophene):fullerene-derivative bulk-heterojunction PV layers and thin gold or silver anodes.We demonstrate that these PV devices allow the simultaneous generation of both electrical power and SPs on their anodes for photoexcitation just above the optical absorption edge of the PV layers,resulting not only in attenuated total reflection,but also in attenuated photocurrent generation(APG)under the SP resonance(SPR)condition.Moreover,we also confirm that the biomolecular interaction of biotin–streptavidin on the PV devices can be precisely detected via apparent SPR angle shifts in the APG spectra,even without the need for complex attenuated total reflection configurations.We highlight our view that APG measurements made using these PV devices show great potential for the development of future generations of compact and highly sensitive SPR-based optical sensors. 展开更多
关键词 attenuated total reflection optical sensors photocurrent generation polymer photovoltaic devices surface plasmon
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