Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of pre...Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of precision spectroscopy and trace gas detection.Here,we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell.Using this instrument,the broadband absorption spectra of several important molecules,including methane,acetylene,water molecules and nitrous oxide,are measured by near real-time data acquisition in the 2800-3500 cm^(-1)spectral region.The achieved minimum detectable absorption of the instrument is 4.4×10^(-8)cm^(-1)·Hz^(-1/2)per spectral element.Broadband spectra of H_(2)0 are fited using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%.Our system also enables precise spectroscopic measurements,and it allows the determination of the spectral line positions and upper state constants of N_(2)O in the(0002)-(1000)band,with results in good agreement with those reported by Toth[Appl.Opt.30,5289(1991)].展开更多
A series of Fe‐Mn/Al2O3 catalysts were prepared and studied for low temperature selective catalytic reduction （SCR） of NO with NH3 in a fixed‐bed reactor. The effects of Fe and Mn on NO conversion and the deactiva...A series of Fe‐Mn/Al2O3 catalysts were prepared and studied for low temperature selective catalytic reduction （SCR） of NO with NH3 in a fixed‐bed reactor. The effects of Fe and Mn on NO conversion and the deactivation of the catalysts were studied. N2 adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, H2 temperature‐programmed reduction, NH3 temperature‐programmed desorption, X‐ray photoelectron spectroscopy （XPS）, thermal gravimetric analysis and Fourier transform infrared spectroscopy were used to character‐ize the catalysts. The 8Fe‐8Mn/Al2O3 catalyst gave 99%of NO conversion at 150？？ and more than 92.6%NO conversion was obtained in a wide low temperature range of 90–210？？. XPS analysis demonstrated that the Fe3＋was the main iron valence state on the catalyst surface and the addition of Mn increased the accumulation of Fe on the surface. The higher specific surface area, enhanced dispersion of amorphous Fe and Mn, improved reduction properties and surface acidity, lower binding energy, higher Mn4＋/Mn3＋ratio and more adsorbed oxygen species resulted in higher NO conversion for the 8Fe‐8Mn/Al2O3 catalyst. In addition, the SCR activity of the 8Fe‐8Mn/Al2O3 cata‐lyst was only slightly decreased in the presence of H2O and SO2, which indicated that the catalyst had better tolerance to H2O and SO2. The reaction temperature was crucial for the SO2 resistance of catalyst and the decrease of catalytic activity caused by SO2 was mainly due to the sulfate salts formed on the catalyst.展开更多
Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made u...Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 （protein amide Ⅱ band）, 1 605 cm-1 （lignin） and 1 650 cm-1 （protein amide I band）.The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves （chocolate spot leaf： 15.42%, 42.98% and 41.61%, ring spot leaf：32.39%, 35.63% and 31.98%, rust leaf： 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf： 24.01%,36.55% and 39.44%）. For sub-peak area ratios （A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654）, those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases.展开更多
Methanol oxidation reaction （MOR） at Pt and Pt electrode surface deposited with various amounts of Ru （denoted as PtxRuy, nominal coverage y is 0.17, 0.27, and 0.44 ML） in 0.1 mol/L HClO4＋0.5 mol/L MeOH has been ...Methanol oxidation reaction （MOR） at Pt and Pt electrode surface deposited with various amounts of Ru （denoted as PtxRuy, nominal coverage y is 0.17, 0.27, and 0.44 ML） in 0.1 mol/L HClO4＋0.5 mol/L MeOH has been studied under potentiostatic conditions by in situ FTIR spectroscopy in attenuated-total-reflection con guration and di erential electro-chemical mass spectrometry under controlled flow conditions. Results reveal that （i） CO is the only methanol-related adsorbate observed by IR spectroscopy at all the Pt and PtRu electrodes examined at potentials from 0.3 V to 0.6 V （vs. RHE）; （ii） at Pt0.56Ru0.44, two IR bands, one from CO adsorbed at Ru islands and the other from COL at Pt substrate are detected, while at other electrodes, only a single band for COL adsorbed at Pt is observed; （iii） MOR activity decreases in the order of Pt0.73Ru0.27〉Pt0.56Ru0.44〉Pt0.83Ru0.17〉Pt; （iv） at 0.5 V, MOR at Pt0.73Ru0.27 reaches a current e ciency of 50% for CO2 production, the turn-over frequency from CH3OH to CO2 is ca. 0.1 molecule/（site sec）. Suggestions for further improving of PtRu catalysts for MOR are provided.展开更多
The remote sensing data which are used by marine fishery forecast only can get the information of ocean surface, while Argo data can provide fishery forecast with temperature and saltinity data of deeper area. To use ...The remote sensing data which are used by marine fishery forecast only can get the information of ocean surface, while Argo data can provide fishery forecast with temperature and saltinity data of deeper area. To use Argo data in cycle, we need to compute its circle to improve the quality of forecast. In 2001- 2008, the longer circle was 62.7 days and 117.5 days, and the shorter circle was 4.9 days and 9.8 days, which were obtained by power spectrum estimation. And there was an unobvious circle of 7 days. There existed big changes in observed profile data amount between years and within a year.展开更多
[Objective] This research aimed to study the FTIR spectra of corn germs and endosperms so as to provide a scientific way for identifying corn of different types. [Method] The corn germs and endosperms of three types w...[Objective] This research aimed to study the FTIR spectra of corn germs and endosperms so as to provide a scientific way for identifying corn of different types. [Method] The corn germs and endosperms of three types were studied by using Fourier transform infrared spectroscopy（FTIR） technology, combined with cluster analysis. [Result] The overall characteristics of original FTIR spectra were basically similar within the range of 700-1 800 cm^-1. The FTIR spectra were mainly composed by the absorption peaks of polysaccharides, proteins and lipids. Within the wavelength range of 700-1 800 cm^-1, there were only tiny differences in original FTIR spectra among the corn germs and endosperms of three different types. The spectra were then processed by using first derivative and second derivative. The second derivative spectra were used for hierarchical cluster analysis（HCA）. The results showed that with the wavelength range of 700-1 800 cm^-1, the second derivative spectra of the 52 samples could be better clustered according to the tree types and corn germ and corn endosperm. The clustering correct rate reached 96.1%.[Conclusion] FTIR technology, combined with cluster analysis, can be used to identify different types of corn germs and endosperms, and it is characterized by convenience and rapidness.展开更多
A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin （β-CD） was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentr...A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin （β-CD） was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate （Li2CO3） to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li2CO3 and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li2CO3 to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.展开更多
Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA w...Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material. The purity of CLA and total recovery of the product was more than 95% and 48%, respectively. The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC) linked to mass spectrometry (MS) and Fourier transform infrared spectroscopy (FTIR). The total amount of the two main isomers (9cis, 11trons-and 10trans, 12cis-CLA) determined by GC was more than 90% of the product.展开更多
The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) i...The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) ion adsorption onto AC-T.The modified activated carbon is characterized by scanning electron microscopy,Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5.Adsorption isotherms and kinetic study suggest that the sorption of Cd(Ⅱ) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption.And the adsorbent has a good reusability.According to the FT-IR and XPS analyses,electrostatic attraction and cation exchange between Cd(Ⅱ) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(Ⅱ) adsorption.展开更多
Microcapsules of salicylic acid （SA） with chitosan were prepared by spray drying method. Various analytical methods were used to characterize the nature of microcapsules. Fourier-transform infrared spectroscopy （F...Microcapsules of salicylic acid （SA） with chitosan were prepared by spray drying method. Various analytical methods were used to characterize the nature of microcapsules. Fourier-transform infrared spectroscopy （FTIR） confirmed the presence of intermolecular interactions between chitosan and SA. Particle size analysis showed that the average size ofmicrocapsules ranged from 2 to 20 pro, Scanning electron microscopy （SEM） studies indicated that the microspheres were spherical and had a relatively smooth surface. Microbiological assay of antibacterial activity for SA and its microcapsules was measured using different bacterial strains. It was found that the antibacterial activity of SA was improved after the formation of microcapsules. The in vitro release profile showed that the microcapsules could control SA release from I h to 4 h. Kinetic studies revealed that the release pattern follows Korsmeyer-Peppas mechanism. Enhanced antibacterial activity of the SA micro- capsules was attributed to the synergistic effects of intermolecular hydrogen-bonding interactions N-H...O and O-H...O=C between SA and chitosan. It was also confirmed by quantum chemical calculation.展开更多
Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-...Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-ray diffraction , X-ray absorption fine structure, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The catalytic per- formance for the higher alcohol synthesis from syngas was tested. The pure H2 treatment showed a high reduction capacity. The presence of a large amount of metallic CoO and low valence state Mo^φ＋ （0〈φ〈2） on the surface suggested a super activity for the CO dissoci- ation and hydrogenation, which promoted hydrocarbons formation and reduced the alcohol selectivity. In contrast, the pure CO-reduced catalyst had a low reduction degree. The Mo and Co species at the catalyst mainly existed in the form of Mo^4＋ and Co^2＋. The syngas- reduced catalyst showed the highest activity and selectivity for the higher alcohols synthesis. We suggest that the syngas treatment had an appropriate reduction capacity that is between those of pure H2 and pure CO and led to the coexistence of multivalent Co species as well as the enrichment of Mo~＋ on the catalyst＇s surface. The synergistic effects between these active species provided a better cooperativity and equilibrium between the CO dissociation, hydrogenation and CO insertion and thus contributed beneficially to the formation of higher alcohols.展开更多
Physicochemical properties of bio-oil obtained from fast pyrolysis of rice husk were studied in the present work.Molecular distillation was used to separate the crude bio-oil into three fractions viz.light fraction,mi...Physicochemical properties of bio-oil obtained from fast pyrolysis of rice husk were studied in the present work.Molecular distillation was used to separate the crude bio-oil into three fractions viz.light fraction,middle fraction and heavy fraction.Their chemical composition was analyzed by gas chromatograph and mass spectrometer（GC-MS）.The thermal behavior,including evaporation and decomposition,was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer（TG-FTIR）.The product distribution was significantly affected by contents of cellulose,hemicellulose and lignin.The bio-oil yield was 46.36%（by mass） and the yield of gaseous products was 27%（by mass）.The chemicals in the bio-oil included acids,aldehydes,ketones,alcohols,phenols,sugars,etc.The light fraction was mainly composed of acids and compounds with lower boiling point temperature,the middle and heavy fractions were consisted of phenols and levoglucosan.The thermal stability of the bio-oil was determined by the interactions and intersolubility of compounds.It was found that the thermal stability of bio-oil was better than the light fraction,but worse than the middle and heavy fractions.展开更多
Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The prese...Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The presence of water in the reaction stream results in a significant increase in NH3selectivity.This result is due to water‐induced hydroxylation promoting NH3formation and the competitive adsorption of H2O and NO at the same sites,which inhibits the reactivity of NO reduction by NH3.展开更多
The effect of the modification of an alumina support with chloride on the structure and the catalytic performance of Ag/Al_(2)O_(3)catalysts(SA)was investigated for the selective catalytic reduction(SCR)of NO using C_...The effect of the modification of an alumina support with chloride on the structure and the catalytic performance of Ag/Al_(2)O_(3)catalysts(SA)was investigated for the selective catalytic reduction(SCR)of NO using C_(3)H_(6)or H_(2)/C_(3)H_(6)as reductants.The Ag/Al_(2)O_(3)catalyst and Cl^(–)-modified Ag/Al_(2)O_(3)catalysts(SA-Cl)were prepared by a conventional impregnation method and characterized by X-ray diffraction,Brunauer-Emmett-Teller isotherm analysis,electron probe microanalysis,transmission electron microscopy,UV-Vis diffuse reflectance spectroscopy,X-ray photoelectron spectroscopy,and hydrogen temperature-programmed reduction.The catalytic activities in the C3H6-SCR and H_(2)/C3H6-SCR reactions were evaluated,and the reaction mechanism was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy and synchrotron vacuum ultraviolet photoionization mass spectroscopy(SVUV-PIMS).We found that Cl^(-)modification of the alumina-supported Ag/Al_(2)O_(3)catalysts facilitated the formation of oxidized silver species(Ag_(n)^(ᵟ+))that catalyze the moderate-temperature oxidation of hydrocarbons into partial oxidation products(mainly acetate species)capable of participating in the SCR reaction.The low-temperature promoting effect of H_(2)on the C3H6-SCR("hydrogen effect")was found to originate from the enhanced decomposition of strongly adsorbed nitrates on the catalyst surface and the conversion of these adsorbed species to–NCO and–CN species.This"H_(2)effect"occurs in the presence of Ag_(n)^(ᵟ+)species rather than the metallic Ag^(0)species.A gaseous intermediate,acrylonitrile(CH_(2)CHCN),was also identified in the H_(2)/C3H6-SCR reaction using SVUV-PIMS.These findings provide novel insights in the structure-activity relationship and reaction mechanisms of the SA-catalyzed HC-SCR reaction of NO.展开更多
A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of...A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.展开更多
The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diff...The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.展开更多
In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice...In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice,forming solid solutions.The catalysts were then used for the selective catalytic reduction(SCR)of NO by CO.The Cu‐doped catalyst exhibited the highest SCR activity;it had a T50(i.e.,50%NO conversion)of only 83°C and a T90(i.e.,90%NO conversion)of 126°C.Such an activity was also higher than in many state‐of‐the‐art catalysts.In situ diffuse reflectance Fourier transform infrared spectroscopy suggested that the MOx‐CeO2 catalysts(M=Co and Fe)mainly followed an Eley‐Rideal reaction mechanism for CO‐SCR.In contrast,a Langmuir‐Hinshelwood SCR reaction mechanism occurred in CuO‐CeO2 owing to the presence of Cu+species,which ensured effective adsorption of CO.This explains why CuO‐CeO2 exhibited the highest activity with regard to the SCR of NO by CO.展开更多
AIM: Real-time and rapid Identification of the malignant tissue can be performed during or before surgical operation. Here we aimed to detect in vivo and in situ colorectal cancer by using Fourier transform infrared (...AIM: Real-time and rapid Identification of the malignant tissue can be performed during or before surgical operation. Here we aimed to detect in vivo and in situ colorectal cancer by using Fourier transform infrared (FTIR) spectroscopy and fiber-optic technology. METHODS: A total of five patients with large intestine cancer were detected in vivo and in situ. Of them, three cases of colon cancer and one case of cecum cancer were detected intraoperatively and in vivo by using a FTIR spectrometer during surgical operation, and one case of rectum cancer was explored non-invasively and in vivo before the surgical operation. Normal and malignant colorectal tissues were detected in vivo and in situ using FTIR spectroscopy on the basis of fundamental studies. RESULTS: There were significant differences between FTIR spectra of normal and malignant colorectal tissues detected in vivo and in situ. Experimental results revealed that the spectral characteristics of normal and malignant tissues found in vivo and in situ were similar to those obtained from in vitro measurement in our previous fundamental research. CONCLUSION: FTIR fiber-optic attenuated total reflectance (ATR) spectroscopy can identify in situ and in vivo colorectal cancer. FTIR spectroscopie method with fiber optics is a non-invasive, rapid, accurate and in vivo cancer detection technique in clinical diagnosis.展开更多
In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was p...In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was prepared by the calcination method and investigated for the CO oxidation. The microstructure and morphology of CeO2-Co3O4 were investigated by the Scanning Electron Microscope, High-resolution transmission electron microscopy, Raman and X-ray photoelectron spectroscopy characterization. The effect of CeO2 doping on Co3O4 for CO oxidation was characterized by in situ X-ray Diffraction (in situ XRD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). In situ XRD was carried out under H2 atmosphere to evaluate the redox property of catalysts. The results indicated that the ceria doping can enhance the reducibility of Co2+ and promote the Co3+-Co2+-Co3+ cycle, owing to the oxygen replenish property of CeO2. Furthermore, adsorbed carbonate species on the surface of CeO2-Co3O4 were investigated by in situ-DRIFTS experiment. It was turned out that carbonate species on ceria promoted cobalt oxide catalysts showed different IR peaks compared with pure cobalt oxide. The carbonate species on ceria promoted catalyst are more active, and similar to free state carbonate species with weak bonding to catalyst surface, which can effectively inhibit catalyst inactivation. This study revealed the mechanism of ceria promoting CO oxidation over cobalt oxide, which will provide theoretical support for the design of efficient CO oxidation catalysts.展开更多
基金supported by the National Natural Science Foundation China(No.42022051,No.U21A2028)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202089)the HFIPS Director's Fund(No.YZJJ202101,No.BJPY2023A02).
文摘Optical frequency combbased Fourier transform spectroscopy has the features of broad spectral bandwidth,high sensitivity,andmultiplexed trace gas detection,which has valuable application potential in the fields of precision spectroscopy and trace gas detection.Here,we report the development of a mid-infrared Fourier transform spectrometer based on an optical frequency comb combined with a Herriott-type multipass cell.Using this instrument,the broadband absorption spectra of several important molecules,including methane,acetylene,water molecules and nitrous oxide,are measured by near real-time data acquisition in the 2800-3500 cm^(-1)spectral region.The achieved minimum detectable absorption of the instrument is 4.4×10^(-8)cm^(-1)·Hz^(-1/2)per spectral element.Broadband spectra of H_(2)0 are fited using the Voigt profile multispectral fitting technique and the consistency of the concentration inversion is 1%.Our system also enables precise spectroscopic measurements,and it allows the determination of the spectral line positions and upper state constants of N_(2)O in the(0002)-(1000)band,with results in good agreement with those reported by Toth[Appl.Opt.30,5289(1991)].
基金supported by the National High Technology Research and Development Program of China (863 Program,2015AA03A401)the National Natural Science Foundation of China (51276039)+1 种基金the Fundamental Research Funds for the Central Universities (020514380020,020514380030)the Postdoctoral Science Foundation of Jiangsu Province,China (1501033A)~~
文摘A series of Fe‐Mn/Al2O3 catalysts were prepared and studied for low temperature selective catalytic reduction （SCR） of NO with NH3 in a fixed‐bed reactor. The effects of Fe and Mn on NO conversion and the deactivation of the catalysts were studied. N2 adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, H2 temperature‐programmed reduction, NH3 temperature‐programmed desorption, X‐ray photoelectron spectroscopy （XPS）, thermal gravimetric analysis and Fourier transform infrared spectroscopy were used to character‐ize the catalysts. The 8Fe‐8Mn/Al2O3 catalyst gave 99%of NO conversion at 150？？ and more than 92.6%NO conversion was obtained in a wide low temperature range of 90–210？？. XPS analysis demonstrated that the Fe3＋was the main iron valence state on the catalyst surface and the addition of Mn increased the accumulation of Fe on the surface. The higher specific surface area, enhanced dispersion of amorphous Fe and Mn, improved reduction properties and surface acidity, lower binding energy, higher Mn4＋/Mn3＋ratio and more adsorbed oxygen species resulted in higher NO conversion for the 8Fe‐8Mn/Al2O3 catalyst. In addition, the SCR activity of the 8Fe‐8Mn/Al2O3 cata‐lyst was only slightly decreased in the presence of H2O and SO2, which indicated that the catalyst had better tolerance to H2O and SO2. The reaction temperature was crucial for the SO2 resistance of catalyst and the decrease of catalytic activity caused by SO2 was mainly due to the sulfate salts formed on the catalyst.
基金Supported by National Natural Science Foundation of China(30960179)Program for Innovative Research Team in Science and Technology in University of Yunnan Province~~
文摘Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 （protein amide Ⅱ band）, 1 605 cm-1 （lignin） and 1 650 cm-1 （protein amide I band）.The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves （chocolate spot leaf： 15.42%, 42.98% and 41.61%, ring spot leaf：32.39%, 35.63% and 31.98%, rust leaf： 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf： 24.01%,36.55% and 39.44%）. For sub-peak area ratios （A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654）, those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases.
文摘Methanol oxidation reaction （MOR） at Pt and Pt electrode surface deposited with various amounts of Ru （denoted as PtxRuy, nominal coverage y is 0.17, 0.27, and 0.44 ML） in 0.1 mol/L HClO4＋0.5 mol/L MeOH has been studied under potentiostatic conditions by in situ FTIR spectroscopy in attenuated-total-reflection con guration and di erential electro-chemical mass spectrometry under controlled flow conditions. Results reveal that （i） CO is the only methanol-related adsorbate observed by IR spectroscopy at all the Pt and PtRu electrodes examined at potentials from 0.3 V to 0.6 V （vs. RHE）; （ii） at Pt0.56Ru0.44, two IR bands, one from CO adsorbed at Ru islands and the other from COL at Pt substrate are detected, while at other electrodes, only a single band for COL adsorbed at Pt is observed; （iii） MOR activity decreases in the order of Pt0.73Ru0.27〉Pt0.56Ru0.44〉Pt0.83Ru0.17〉Pt; （iv） at 0.5 V, MOR at Pt0.73Ru0.27 reaches a current e ciency of 50% for CO2 production, the turn-over frequency from CH3OH to CO2 is ca. 0.1 molecule/（site sec）. Suggestions for further improving of PtRu catalysts for MOR are provided.
基金supported by the National ‘863’ high-tech R&D Project of China (No.2007AA092202)special research fund for the national non-profit institutes (East China Sea Fisheries Research Institute, No. 2009T08)
文摘The remote sensing data which are used by marine fishery forecast only can get the information of ocean surface, while Argo data can provide fishery forecast with temperature and saltinity data of deeper area. To use Argo data in cycle, we need to compute its circle to improve the quality of forecast. In 2001- 2008, the longer circle was 62.7 days and 117.5 days, and the shorter circle was 4.9 days and 9.8 days, which were obtained by power spectrum estimation. And there was an unobvious circle of 7 days. There existed big changes in observed profile data amount between years and within a year.
基金Supported by National Natural Science Foundation of China(30960179)Natural Science Foundation of Yunnan Province(2007A048M)~~
文摘[Objective] This research aimed to study the FTIR spectra of corn germs and endosperms so as to provide a scientific way for identifying corn of different types. [Method] The corn germs and endosperms of three types were studied by using Fourier transform infrared spectroscopy（FTIR） technology, combined with cluster analysis. [Result] The overall characteristics of original FTIR spectra were basically similar within the range of 700-1 800 cm^-1. The FTIR spectra were mainly composed by the absorption peaks of polysaccharides, proteins and lipids. Within the wavelength range of 700-1 800 cm^-1, there were only tiny differences in original FTIR spectra among the corn germs and endosperms of three different types. The spectra were then processed by using first derivative and second derivative. The second derivative spectra were used for hierarchical cluster analysis（HCA）. The results showed that with the wavelength range of 700-1 800 cm^-1, the second derivative spectra of the 52 samples could be better clustered according to the tree types and corn germ and corn endosperm. The clustering correct rate reached 96.1%.[Conclusion] FTIR technology, combined with cluster analysis, can be used to identify different types of corn germs and endosperms, and it is characterized by convenience and rapidness.
基金ACKNOWLEDGMENTS This work was supported by the Innovation Foundation of Graduate Students in University of Science and Technology of China （No.KD2008020）, and the Natural Science Foundation of Anhui Province （No.090416228）.
文摘A small shielding effect on the hydrogen atoms of chiral carbons of β-cyclodextrin （β-CD） was detected by 1H nuclear magnetic resonance, but a large environmental change of the chiral carbon atoms at high concentration ratios of lithium carbonate （Li2CO3） to β-CD was observed by polarimetry in aqueous solution. These findings urged us to investigate whether different formation conditions of the molecule-ion system between Li2CO3 and β-CD in solid state were involved in different spectral performances. To answer the question, we prepared three adducts of Li2CO3 to β-CD, i.e., samples 1, 2, and 3, by magnetic stirring, solvothermal and grinding conditions, respectively. Powder X-ray diffraction and Fourier transformation infrared spectroscopy provided the information of formation of the three molecule-ion adducts. Besides, scanning electron microscope images provided different surface information of the three adducts. Further, significant spectral differences in thermal behavior of these adducts were found by thermogravimetry and derivative thermogravimetry.
文摘Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material. The purity of CLA and total recovery of the product was more than 95% and 48%, respectively. The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC) linked to mass spectrometry (MS) and Fourier transform infrared spectroscopy (FTIR). The total amount of the two main isomers (9cis, 11trons-and 10trans, 12cis-CLA) determined by GC was more than 90% of the product.
基金Supported by the Fundamental Research Funds for the Central Universities(TD2013-2,2012LYB33)the National Natural Science Foundation of China(51278053,21373032)grant-in-aid from Kochi University of Technology and China Scholarship Council
文摘The adsorption of aqueous cadmium ions(Cd(Ⅱ)) have been investigated for modified activated carbon(AC-T)with oxygen-containing functional groups.The oxygen-containing groups of AC-T play an important role in Cd(Ⅱ) ion adsorption onto AC-T.The modified activated carbon is characterized by scanning electron microscopy,Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).The results of batch experiments indicate that the maximal adsorption could be achieved over the broad pH range of 4.5 to 6.5.Adsorption isotherms and kinetic study suggest that the sorption of Cd(Ⅱ) onto AC-T produces monolayer coverage and that adsorption is controlled by chemical adsorption.And the adsorbent has a good reusability.According to the FT-IR and XPS analyses,electrostatic attraction and cation exchange between Cd(Ⅱ) and oxygen-containing functional groups on AC-T are dominant mechanisms for Cd(Ⅱ) adsorption.
基金Supported by the National Natural Science Foundation of China(21376279,21425627)the Science and Technology Major Program of Guangdong Province(2012A080103005)+2 种基金the Fundamental Research Funds for the Central Universities(14lgpy28)Guangzhou Science and Technology Plan Projects(2014J4100125)the Dayawan Science and Technology Plan Projects(2013A01013)
文摘Microcapsules of salicylic acid （SA） with chitosan were prepared by spray drying method. Various analytical methods were used to characterize the nature of microcapsules. Fourier-transform infrared spectroscopy （FTIR） confirmed the presence of intermolecular interactions between chitosan and SA. Particle size analysis showed that the average size ofmicrocapsules ranged from 2 to 20 pro, Scanning electron microscopy （SEM） studies indicated that the microspheres were spherical and had a relatively smooth surface. Microbiological assay of antibacterial activity for SA and its microcapsules was measured using different bacterial strains. It was found that the antibacterial activity of SA was improved after the formation of microcapsules. The in vitro release profile showed that the microcapsules could control SA release from I h to 4 h. Kinetic studies revealed that the release pattern follows Korsmeyer-Peppas mechanism. Enhanced antibacterial activity of the SA micro- capsules was attributed to the synergistic effects of intermolecular hydrogen-bonding interactions N-H...O and O-H...O=C between SA and chitosan. It was also confirmed by quantum chemical calculation.
文摘Activated carbon supported Mo-based catalysts were prepared and reduced under different activation atmospheres, including pure H2, syngas （H2/CO=2/1）, and pure CO. The cat- alysts structures were characterized by X-ray diffraction , X-ray absorption fine structure, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The catalytic per- formance for the higher alcohol synthesis from syngas was tested. The pure H2 treatment showed a high reduction capacity. The presence of a large amount of metallic CoO and low valence state Mo^φ＋ （0〈φ〈2） on the surface suggested a super activity for the CO dissoci- ation and hydrogenation, which promoted hydrocarbons formation and reduced the alcohol selectivity. In contrast, the pure CO-reduced catalyst had a low reduction degree. The Mo and Co species at the catalyst mainly existed in the form of Mo^4＋ and Co^2＋. The syngas- reduced catalyst showed the highest activity and selectivity for the higher alcohols synthesis. We suggest that the syngas treatment had an appropriate reduction capacity that is between those of pure H2 and pure CO and led to the coexistence of multivalent Co species as well as the enrichment of Mo~＋ on the catalyst＇s surface. The synergistic effects between these active species provided a better cooperativity and equilibrium between the CO dissociation, hydrogenation and CO insertion and thus contributed beneficially to the formation of higher alcohols.
基金Supported by the International Science and Technology Cooperation Program of China（2009DFA61050） the National High Technology Research and Development Program of China（2009AA05Z407） the National Natural Science Foundation of China（50676085 90610035）
文摘Physicochemical properties of bio-oil obtained from fast pyrolysis of rice husk were studied in the present work.Molecular distillation was used to separate the crude bio-oil into three fractions viz.light fraction,middle fraction and heavy fraction.Their chemical composition was analyzed by gas chromatograph and mass spectrometer（GC-MS）.The thermal behavior,including evaporation and decomposition,was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer（TG-FTIR）.The product distribution was significantly affected by contents of cellulose,hemicellulose and lignin.The bio-oil yield was 46.36%（by mass） and the yield of gaseous products was 27%（by mass）.The chemicals in the bio-oil included acids,aldehydes,ketones,alcohols,phenols,sugars,etc.The light fraction was mainly composed of acids and compounds with lower boiling point temperature,the middle and heavy fractions were consisted of phenols and levoglucosan.The thermal stability of the bio-oil was determined by the interactions and intersolubility of compounds.It was found that the thermal stability of bio-oil was better than the light fraction,but worse than the middle and heavy fractions.
基金supported by the National Natural Science Foundation of China (21463015)the Provincial Applied Fundamental Research Program of Yunnan (2014FA045)the National High Technology Research and Development Program of China (863 Program,2015AA034603)~~
文摘Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The presence of water in the reaction stream results in a significant increase in NH3selectivity.This result is due to water‐induced hydroxylation promoting NH3formation and the competitive adsorption of H2O and NO at the same sites,which inhibits the reactivity of NO reduction by NH3.
文摘The effect of the modification of an alumina support with chloride on the structure and the catalytic performance of Ag/Al_(2)O_(3)catalysts(SA)was investigated for the selective catalytic reduction(SCR)of NO using C_(3)H_(6)or H_(2)/C_(3)H_(6)as reductants.The Ag/Al_(2)O_(3)catalyst and Cl^(–)-modified Ag/Al_(2)O_(3)catalysts(SA-Cl)were prepared by a conventional impregnation method and characterized by X-ray diffraction,Brunauer-Emmett-Teller isotherm analysis,electron probe microanalysis,transmission electron microscopy,UV-Vis diffuse reflectance spectroscopy,X-ray photoelectron spectroscopy,and hydrogen temperature-programmed reduction.The catalytic activities in the C3H6-SCR and H_(2)/C3H6-SCR reactions were evaluated,and the reaction mechanism was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy and synchrotron vacuum ultraviolet photoionization mass spectroscopy(SVUV-PIMS).We found that Cl^(-)modification of the alumina-supported Ag/Al_(2)O_(3)catalysts facilitated the formation of oxidized silver species(Ag_(n)^(ᵟ+))that catalyze the moderate-temperature oxidation of hydrocarbons into partial oxidation products(mainly acetate species)capable of participating in the SCR reaction.The low-temperature promoting effect of H_(2)on the C3H6-SCR("hydrogen effect")was found to originate from the enhanced decomposition of strongly adsorbed nitrates on the catalyst surface and the conversion of these adsorbed species to–NCO and–CN species.This"H_(2)effect"occurs in the presence of Ag_(n)^(ᵟ+)species rather than the metallic Ag^(0)species.A gaseous intermediate,acrylonitrile(CH_(2)CHCN),was also identified in the H_(2)/C3H6-SCR reaction using SVUV-PIMS.These findings provide novel insights in the structure-activity relationship and reaction mechanisms of the SA-catalyzed HC-SCR reaction of NO.
基金supported by the National Key R&D Program of China(2016YFB0600305)~~
文摘A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.
基金Project(2007AA03Z0455) supported by the National High-Technology Research and Development Program of ChinaProject(BE2009168) supported by the Natural Science Foundation of Jiangsu Province in ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institution,China
文摘The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.
文摘In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice,forming solid solutions.The catalysts were then used for the selective catalytic reduction(SCR)of NO by CO.The Cu‐doped catalyst exhibited the highest SCR activity;it had a T50(i.e.,50%NO conversion)of only 83°C and a T90(i.e.,90%NO conversion)of 126°C.Such an activity was also higher than in many state‐of‐the‐art catalysts.In situ diffuse reflectance Fourier transform infrared spectroscopy suggested that the MOx‐CeO2 catalysts(M=Co and Fe)mainly followed an Eley‐Rideal reaction mechanism for CO‐SCR.In contrast,a Langmuir‐Hinshelwood SCR reaction mechanism occurred in CuO‐CeO2 owing to the presence of Cu+species,which ensured effective adsorption of CO.This explains why CuO‐CeO2 exhibited the highest activity with regard to the SCR of NO by CO.
基金Supported by the National Natural Science Foundation of China, No. 30371604 State Key Project of China, No. 2002CCA01900
文摘AIM: Real-time and rapid Identification of the malignant tissue can be performed during or before surgical operation. Here we aimed to detect in vivo and in situ colorectal cancer by using Fourier transform infrared (FTIR) spectroscopy and fiber-optic technology. METHODS: A total of five patients with large intestine cancer were detected in vivo and in situ. Of them, three cases of colon cancer and one case of cecum cancer were detected intraoperatively and in vivo by using a FTIR spectrometer during surgical operation, and one case of rectum cancer was explored non-invasively and in vivo before the surgical operation. Normal and malignant colorectal tissues were detected in vivo and in situ using FTIR spectroscopy on the basis of fundamental studies. RESULTS: There were significant differences between FTIR spectra of normal and malignant colorectal tissues detected in vivo and in situ. Experimental results revealed that the spectral characteristics of normal and malignant tissues found in vivo and in situ were similar to those obtained from in vitro measurement in our previous fundamental research. CONCLUSION: FTIR fiber-optic attenuated total reflectance (ATR) spectroscopy can identify in situ and in vivo colorectal cancer. FTIR spectroscopie method with fiber optics is a non-invasive, rapid, accurate and in vivo cancer detection technique in clinical diagnosis.
基金supported by the State Key Research Development Program of China(2016YFA0204200)the National Natural Science Foundation of China(21822603,21577036,21773062)+3 种基金the Shanghai Pujiang Program(17PJD011)the Zhejiang public welfare technology research plan/rural agriculture(LGN18B010001)the Zhejiang provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing(NO:2016KF0005)the scientific research project of Zhejiang provincial education department(Y201839892)~~
文摘In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was prepared by the calcination method and investigated for the CO oxidation. The microstructure and morphology of CeO2-Co3O4 were investigated by the Scanning Electron Microscope, High-resolution transmission electron microscopy, Raman and X-ray photoelectron spectroscopy characterization. The effect of CeO2 doping on Co3O4 for CO oxidation was characterized by in situ X-ray Diffraction (in situ XRD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). In situ XRD was carried out under H2 atmosphere to evaluate the redox property of catalysts. The results indicated that the ceria doping can enhance the reducibility of Co2+ and promote the Co3+-Co2+-Co3+ cycle, owing to the oxygen replenish property of CeO2. Furthermore, adsorbed carbonate species on the surface of CeO2-Co3O4 were investigated by in situ-DRIFTS experiment. It was turned out that carbonate species on ceria promoted cobalt oxide catalysts showed different IR peaks compared with pure cobalt oxide. The carbonate species on ceria promoted catalyst are more active, and similar to free state carbonate species with weak bonding to catalyst surface, which can effectively inhibit catalyst inactivation. This study revealed the mechanism of ceria promoting CO oxidation over cobalt oxide, which will provide theoretical support for the design of efficient CO oxidation catalysts.
