Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at tempe...Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at temperatures between 450℃ and 900℃ in N_2 artmosphere. Then, in a successive activation stage, the product carbonized at 600℃ was activated in steam at 450-900℃ for 30 min, and at 600℃ for 5-30 min. The other carbonization products were activated at 600 and 900℃ for 30 min respectively. The products activated at 900℃ were then activated at 450℃ for 30 min again. The starting materiah carbonized products and all activation products were examined by FT-IR spectroscopy and some products were examined by X-ray photoelectron spectroscope (XPS). And the yields of the carbonized and activated products were calculated. By analysing these spectra, the amount of oxygen-containing functional groups of the activated products attained under various activation time, various activation temperature and various previous carbonization temperature was determined.展开更多
To better understand the nature of carbon nanotubes supported Co-Mo catalysts （Co-Mo/CNTs） for selective hydrodesulfurization （HDS） of fluid catalytic cracking （FCC） gasoline, studies are carried out using in si...To better understand the nature of carbon nanotubes supported Co-Mo catalysts （Co-Mo/CNTs） for selective hydrodesulfurization （HDS） of fluid catalytic cracking （FCC） gasoline, studies are carried out using in situ Fourier transform infrared spectroscopy （FT-IR）. The catalytic performances of Co-Mo/CNTs catalysts were evaluated with a mixture of cyclohexane, diisobutylene, cyclohexene, 1-octene （60 ： 30 ： 5 ： 5, volume ratio） and thiophene （0.5%, ratio of total weight） as model compounds to simulate FCC gasoline. The HDS experimental results suggested that the HDS activity and selectivity of Co-Mo/CNTs catalysts were affected by Co/Mo ratio; the optimal Co/Mo atomic ratio is about 0.4, and the optimum reaction temperature is 260 ℃. The in situ FT-IR studies revealed that 1-octene can be completely saturated at 200 ℃. In the FT-IR spectra of diisobutylene, the characteristic absorption peak around 3081 cm^-1 for the stretching vibration peak of =C-H bond was still clear at 320 ℃ indicating that diisobutylene is difficult to be hydrogenated. As for the thiophene, no characteristic absorption peak could be found around 3092 cm^-1 and 835 cm^-1 when the reaction temperature was raised to 280 ℃, indicating that thiophene had been completely hydrodesulfurized. On the basis of FT-IR results, it can be deduced that thiophene HDS reaction occurred mainly through direct hydrogenolysis route, whereas thiophene HDS and diisobutylene hydrogenation reaction over Co-Mo/CNTs catalysts might occur on two different kinds of active sites.展开更多
The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, ex...The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, excipients or as active in drugs has largely increased these recent years. The surface clay material presents hydroxyl groups, which can link very easily water molecules. These hydroxyl groups can react with organic groups and by their vibration in the infra-red region, FT-IR can be easily used as a technical method for surface clay characterization. In this paper, we focus on the determination of Lewis and Bronsted acid sites on the clay surface, a critical review of the sample preparation, the surface characterization of bulk clay and the modified surface clay samples using FT-IR spectroscopy.展开更多
The Fourier Transform Infrared (FT-IR) spectroscopy is by far known to be a useful technique for qualitative and quantitative analysis of asbestos in bulk samples, since all asbestos species exhibit intense absorption...The Fourier Transform Infrared (FT-IR) spectroscopy is by far known to be a useful technique for qualitative and quantitative analysis of asbestos in bulk samples, since all asbestos species exhibit intense absorption peaks in the 4000 - 400 cm-1 region of the infrared spectrum. In the present work, we compare the accuracy and precision of two analytical procedures (the Linear Calibration Curve Method and the Method of Addition) for the quantitative determination of asbestos in a host matrix. We have found that, providing careful samples preparation, both techniques quantify the asbestos content at the level of few micrograms with good precision. Due to less expensive equipment requirements and shorter analysis time, FT-IR can be a competitive analytical technique in the characterization of asbestos containing material with the respect to diffractometry or electron microscopy.展开更多
The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecul...The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm-1 for Mo2N/Al2O3 catalyst, 2054 cm-1 for MozC/Al2O3 catalyst and 2037 cm-1 for MoP/Al2O3 catalyst, respectively. A strong band at 2200 cm-1 for Mo2N/Al2O3 catalyst, which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms, and a weak band at 2196 cm-1 for Mo2C/Al2O3 catalyst, which could be attributed to CCO species, were also detected. CO adsorbed on fresh Mo2N/Al2O3 catalyst, Mo2C/Al2O3 catalyst and MoP/Al2O3 catalyst, showed strong molecular adsorption, just like noble metals. Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo2N/Al2O3, Mo2C/Al2O3 and MoP/Al2O3 catalysts and noble metals.展开更多
A Nicolet-200SXV FT-IR spectrometer combined with an exciting light set-up has been applied to determine the shallow impurity concentration in detector-grade silicon. The detection sensitivity of boron concentration i...A Nicolet-200SXV FT-IR spectrometer combined with an exciting light set-up has been applied to determine the shallow impurity concentration in detector-grade silicon. The detection sensitivity of boron concentration is high up to 7.8 × 10-12. The calibration curve of boron concentration in high-purity silicon has been obtained, from which the experimental value of calibration factor of boron concentration in silicon is demonstrated to be 1.15 × 1013 cm-1.展开更多
The spontaneous condensation of the amphiphilic N-（O,O-dihexadecyl）phosphorylalanine on the cast film was observed by in situ investigation of transmission infrared spectroscopy The particular orientation and ordere...The spontaneous condensation of the amphiphilic N-（O,O-dihexadecyl）phosphorylalanine on the cast film was observed by in situ investigation of transmission infrared spectroscopy The particular orientation and ordered packing of the monomers within the multilayers of the cast film is concluded to attribute to the spontaneous condensation between the monomers.展开更多
Background:Cotton gin trash(CGT)is a lignocellulosic residue that can be used in the production of cellulosic ethanol.In a previous research,the sequential use of ultrasonication,liquid hot water,and ligninolytic enzy...Background:Cotton gin trash(CGT)is a lignocellulosic residue that can be used in the production of cellulosic ethanol.In a previous research,the sequential use of ultrasonication,liquid hot water,and ligninolytic enzymes was selected as pretreatment for the production of ethanol from CGT.However,an increment in the ethanol production is necessary.To accomplish that,this research evaluated the effect of pretreating CGT using alkaline ultrasonication before a liquid hot water and ligninolytic enzymes pretreatments for ethanol production.Three NaOH concentrations(5%,10%,and 15%)were employed for the alkaline ultrasonication.Additionally,this work is one of the first applications of Fourier transform infrared(FT-IR)spectrum and principal component analysis(PCA)as fast methodology to identify the differences in the biomass after different types of pretreatments.Results:The three concentrations employed for the alkaline ultrasonication pretreatment produced ethanol yields and cellulose conversions higher than the experiment without NaOH.Furthermore,15%NaOH concentration achieved twofold increment yield versus the treatment without NaOH.The FT-IR spectrum confirmed modifications in the CGT structure in the different pretreatments.PCA was helpful to determine differences between the pretreated and un-pretreated biomass and to evaluate how the CGT structure changed after each treatment.Conclusions:The combination of alkali ultrasonication hydrolysis,liquid hot water,and ligninolytic enzymes using 15%of NaOH improved 35%the ethanol yield compared with the original treatment.Additionally,we demonstrated the use of PCA to identify the modifications in the biomass structure after different types of pretreatments and conditions.展开更多
In this editorial,we comment on the recent article by Fei et al exploring the field of near-infrared spectroscopy(NIRS)research in schizophrenia from a bibliometrics perspective.In recent years,NIRS has shown unique a...In this editorial,we comment on the recent article by Fei et al exploring the field of near-infrared spectroscopy(NIRS)research in schizophrenia from a bibliometrics perspective.In recent years,NIRS has shown unique advantages in the auxiliary diagnosis of schizophrenia,and the introduction of bibliometrics has provided a macro perspective for research in this field.Despite the opportunities brought about by these technological developments,remaining challenges require multidi-sciplinary approach to devise a reliable and accurate diagnosis system for schizo-phrenia.Nonetheless,NIRS-assisted technology is expected to contribute to the division of methods for early intervention and treatment of schizophrenia.展开更多
This communication looks at the photo-oxidation of polythene and polypropylene plastic bottle tops that are placed on soil in a hot arid environment. The degree of oxidation of the plastic is monitored by FT-IR spectr...This communication looks at the photo-oxidation of polythene and polypropylene plastic bottle tops that are placed on soil in a hot arid environment. The degree of oxidation of the plastic is monitored by FT-IR spectroscopy. It is noted that while different bottle top types photo-oxidize at different rates, all show an appreciable level of oxidation after half a year of exposure to the environment. The oxidation leads to brittleness of the plastic, which leads to fissure formation in bottle tops of little thickness. This leads to fragmentation of the material upon impact, making plastic bottle tops an appreciable source of microplastics.展开更多
The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo_2C/Al_2O_3 catalyst have been studied by insitu FT-IR spectroscopy.Linearly adsorbed CH_3CN and CH_3CH_2NH_2 were formed after CH_3CN adsorption...The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo_2C/Al_2O_3 catalyst have been studied by insitu FT-IR spectroscopy.Linearly adsorbed CH_3CN and CH_3CH_2NH_2 were formed after CH_3CN adsorption on the Mo_2C/ Al_2O_3 catalyst.The appearance of a strong band at 1578 cm^(-1) indicates that CH_3CN was reactive with hydrogen on the Mo_2C/Al_2O_3 catalyst.展开更多
In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were c...In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.展开更多
AIM: To investigate the special Fourier transform infraredspectroscopy (FT-IR) spectra in normal and cancerous tissuesof esophagus.METHODS: Twenty-seven pairs of normal and canceroustissues of esophagus were studied b...AIM: To investigate the special Fourier transform infraredspectroscopy (FT-IR) spectra in normal and cancerous tissuesof esophagus.METHODS: Twenty-seven pairs of normal and canceroustissues of esophagus were studied by using FT-IR and thespecial spectra characteristics were analyzed in differenttissues.RESULTS: Different spectra were found in normal andcancerous tissues. The peak at 1 550/cm was weak andwide in cancerous tissues but strong and high in normaltissues.The ratio of I1 647/I1 550 was 2.0 in normal tissuesand 2.36 in cancerous tissues (P＜0.05). The ratio of Ⅰ1 550/I 1 080 was 4.5 in normal tissues and 3.4 in canceroustissues (P＜0.01). The peak at 1453/cm was higher than at1 402/cm in normal tissue and lower than at 1 402/cm incancerous tissues.CONCLUSION: The results indicate that F-FIR may be used in clinical diagnosis.展开更多
A simple method to obtain large red crystals of cytochrome bc1 complex from beef heart mitochondria has been developed. These crystals are very stable. Their shapes are retained for a long time in tip-sealed Pasteur p...A simple method to obtain large red crystals of cytochrome bc1 complex from beef heart mitochondria has been developed. These crystals are very stable. Their shapes are retained for a long time in tip-sealed Pasteur pipets placed in a refrigerator. The structure of crystalline cytochrome bc1 complex by micro FT-IR spectroscopy has been investigated. Based on the IR spectra of cytochrome c, the empirical assignments of the major infrared frequencies of cytochrome bc1 complex are given. Infrared frequencies and relative intensities of variable orientation and section of crystal are significantly different. These imply that infrared spectral characterization of the membrane protein crystallization is associated with the variable symmetries and orientations of the structure. Experimental results show that phospholipid exists in the crystal of cytochrome bc1 complex. The membrane protein is probably spanned on the mitochondrial membrane and buried in phospholipid bilayer in an asymmetric manner.展开更多
The orientation and structural characterization of the ultrathin film of azobenzene-containing amphiphilic compound, C_ 12AzoNaph(1,4)C_6N +Br -, were studied in the present study. The compound can form a stable m...The orientation and structural characterization of the ultrathin film of azobenzene-containing amphiphilic compound, C_ 12AzoNaph(1,4)C_6N +Br -, were studied in the present study. The compound can form a stable monolayer with sodium dextrin sulfate(SDS) by means of electrostatic interaction. Fourier-transform infrared(FT-IR) and near-infrared surface-enhanced Raman scattering(NIR-SERS) spectroscopies were used to study the orientation and characterize the structure of the Langmuir-Blodgett(LB) film and the dipping film. The FT-IR spectra indicate that the alkyl tail is nearly perpendicular to the substrate surface without any aggregation and adopts largely trans-zigzag conformation in the LB film. The NIR-SERS spectra demonstrate that the chromorphoric part in C_ 12AzoNaph(1,4)C_6N +Br is also nearly perpendicular to the surface of silver substrate both in the dipping film and the LB film. A new 'sandwiched system' model was designed to investigate the orientation and structural characterization of the chromophoric part in the multi-monolayer LB films on the non-SERS active substrate. The SERS mechanism of the 'sandwiched system' is discussed in the present paper.展开更多
We investigated bleached human hair by FT-IR microspectroscopy and chemical imaging. The cross sectioned hair is approximately 90 μm in diameter, showed cuticle and cortex in chemical imaging. Differential amide I/II...We investigated bleached human hair by FT-IR microspectroscopy and chemical imaging. The cross sectioned hair is approximately 90 μm in diameter, showed cuticle and cortex in chemical imaging. Differential amide I/II absorbance ratio and broadening amide I band between in the cortex and cuticle were confirmed in FT-IR microspectroscopy and chemical imaging. The cystine monoxide band from the products of disulfide oxidation of the amino acid cystine is associated with hair damaging during bleaching process. With increase bleaching time, the band for cystine monoxide shows more intense and larger area in chemical image. The spatially chemical change was investigated in detail by FT-IR microspectroscopy and chemical imaging during the bleached process.展开更多
Laser spectroscopic imaging techniques have received tremendous attention in the-eld of cancer diagnosis due to their high sensitivity,high temporal resolution,and short acquisition time.However,the limited tissue pen...Laser spectroscopic imaging techniques have received tremendous attention in the-eld of cancer diagnosis due to their high sensitivity,high temporal resolution,and short acquisition time.However,the limited tissue penetration of the laser is still a challenge for the in vivo diagnosis of deep-seated lesions.Nanomaterials have been universally integrated with spectroscopic imaging techniques for deeper cancer diagnosis in vivo.The components,morphology,and sizes of nanomaterials are delicately designed,which could realize cancer diagnosis in vivo or in situ.Considering the enhanced signal emitting from the nanomaterials,we emphasized their combination with spectroscopic imaging techniques for cancer diagnosis,like the surface-enhanced Raman scattering(SERS),photoacoustic,fluorescence,and laser-induced breakdown spectroscopy(LIBS).Applications ofthe above spectroscopic techniques offer new prospectsfor cancer diagnosis.展开更多
Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson...Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.展开更多
BACKGROUND Compared with current methods used to assess schizophrenia,near-infrared spectroscopy(NIRS)has the advantages of providing noninvasive and real-time monitoring of functional activities of the brain and prov...BACKGROUND Compared with current methods used to assess schizophrenia,near-infrared spectroscopy(NIRS)has the advantages of providing noninvasive and real-time monitoring of functional activities of the brain and providing direct and objective assessment information.AIM To explore the research field of NIRS in schizophrenia from the perspective of bibliometrics.METHODS The Web of Science Core Collection was used as the search tool,and the last search date was April 21,2024.Bibliometric indicators,such as the numbers of publications and citations,were recorded.Bibliometrix and VOS viewer were used for visualization analysis.RESULTS A total of 355 articles from 105 journals were included in the analysis.The overall trend of the number of research publications increased.Schizophrenia Research was identified as an influential journal in the field.Kasai K was one of the most influential and productive authors in this area of research.The University of Tokyo and Japan had the highest scientific output for an institution and a country,respectively.The top ten keywords were“schizophrenia”,“activation”,“near-infrared spectroscopy”,“verbal fluency task”,“cortex”,“brain,performance”,“workingmemory”,“brain activation”,and“prefrontal cortex”.CONCLUSION Our study reveals the evolution of knowledge and emerging trends in the field of NIRS in schizophrenia.the research focus is shifting from underlying disease characteristics to more in-depth studies of brain function and physiological mechanisms.展开更多
文摘Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at temperatures between 450℃ and 900℃ in N_2 artmosphere. Then, in a successive activation stage, the product carbonized at 600℃ was activated in steam at 450-900℃ for 30 min, and at 600℃ for 5-30 min. The other carbonization products were activated at 600 and 900℃ for 30 min respectively. The products activated at 900℃ were then activated at 450℃ for 30 min again. The starting materiah carbonized products and all activation products were examined by FT-IR spectroscopy and some products were examined by X-ray photoelectron spectroscope (XPS). And the yields of the carbonized and activated products were calculated. By analysing these spectra, the amount of oxygen-containing functional groups of the activated products attained under various activation time, various activation temperature and various previous carbonization temperature was determined.
基金National Basic Research Program of China ("973"Program,No.2004CB217807)
文摘To better understand the nature of carbon nanotubes supported Co-Mo catalysts （Co-Mo/CNTs） for selective hydrodesulfurization （HDS） of fluid catalytic cracking （FCC） gasoline, studies are carried out using in situ Fourier transform infrared spectroscopy （FT-IR）. The catalytic performances of Co-Mo/CNTs catalysts were evaluated with a mixture of cyclohexane, diisobutylene, cyclohexene, 1-octene （60 ： 30 ： 5 ： 5, volume ratio） and thiophene （0.5%, ratio of total weight） as model compounds to simulate FCC gasoline. The HDS experimental results suggested that the HDS activity and selectivity of Co-Mo/CNTs catalysts were affected by Co/Mo ratio; the optimal Co/Mo atomic ratio is about 0.4, and the optimum reaction temperature is 260 ℃. The in situ FT-IR studies revealed that 1-octene can be completely saturated at 200 ℃. In the FT-IR spectra of diisobutylene, the characteristic absorption peak around 3081 cm^-1 for the stretching vibration peak of =C-H bond was still clear at 320 ℃ indicating that diisobutylene is difficult to be hydrogenated. As for the thiophene, no characteristic absorption peak could be found around 3092 cm^-1 and 835 cm^-1 when the reaction temperature was raised to 280 ℃, indicating that thiophene had been completely hydrodesulfurized. On the basis of FT-IR results, it can be deduced that thiophene HDS reaction occurred mainly through direct hydrogenolysis route, whereas thiophene HDS and diisobutylene hydrogenation reaction over Co-Mo/CNTs catalysts might occur on two different kinds of active sites.
文摘The present paper should be considered as a review of the application of Fourier Transform Infra-Red for surface clay characterization. The application of surface clay materials for water treatment, oil adsorption, excipients or as active in drugs has largely increased these recent years. The surface clay material presents hydroxyl groups, which can link very easily water molecules. These hydroxyl groups can react with organic groups and by their vibration in the infra-red region, FT-IR can be easily used as a technical method for surface clay characterization. In this paper, we focus on the determination of Lewis and Bronsted acid sites on the clay surface, a critical review of the sample preparation, the surface characterization of bulk clay and the modified surface clay samples using FT-IR spectroscopy.
文摘The Fourier Transform Infrared (FT-IR) spectroscopy is by far known to be a useful technique for qualitative and quantitative analysis of asbestos in bulk samples, since all asbestos species exhibit intense absorption peaks in the 4000 - 400 cm-1 region of the infrared spectrum. In the present work, we compare the accuracy and precision of two analytical procedures (the Linear Calibration Curve Method and the Method of Addition) for the quantitative determination of asbestos in a host matrix. We have found that, providing careful samples preparation, both techniques quantify the asbestos content at the level of few micrograms with good precision. Due to less expensive equipment requirements and shorter analysis time, FT-IR can be a competitive analytical technique in the characterization of asbestos containing material with the respect to diffractometry or electron microscopy.
基金supported by the National Nature Science Foundation of China(No.20903054).
文摘The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm-1 for Mo2N/Al2O3 catalyst, 2054 cm-1 for MozC/Al2O3 catalyst and 2037 cm-1 for MoP/Al2O3 catalyst, respectively. A strong band at 2200 cm-1 for Mo2N/Al2O3 catalyst, which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms, and a weak band at 2196 cm-1 for Mo2C/Al2O3 catalyst, which could be attributed to CCO species, were also detected. CO adsorbed on fresh Mo2N/Al2O3 catalyst, Mo2C/Al2O3 catalyst and MoP/Al2O3 catalyst, showed strong molecular adsorption, just like noble metals. Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo2N/Al2O3, Mo2C/Al2O3 and MoP/Al2O3 catalysts and noble metals.
文摘A Nicolet-200SXV FT-IR spectrometer combined with an exciting light set-up has been applied to determine the shallow impurity concentration in detector-grade silicon. The detection sensitivity of boron concentration is high up to 7.8 × 10-12. The calibration curve of boron concentration in high-purity silicon has been obtained, from which the experimental value of calibration factor of boron concentration in silicon is demonstrated to be 1.15 × 1013 cm-1.
基金supports from the National Natural Science Foundation of China(No.20272032,NSFCBIC20320130046)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE,P.R.C.(TRAPOYT)the Specialized research Fund for the Doctoral Program of Higher Education(SRFDP)(No.20030003049)
文摘The spontaneous condensation of the amphiphilic N-（O,O-dihexadecyl）phosphorylalanine on the cast film was observed by in situ investigation of transmission infrared spectroscopy The particular orientation and ordered packing of the monomers within the multilayers of the cast film is concluded to attribute to the spontaneous condensation between the monomers.
文摘Background:Cotton gin trash(CGT)is a lignocellulosic residue that can be used in the production of cellulosic ethanol.In a previous research,the sequential use of ultrasonication,liquid hot water,and ligninolytic enzymes was selected as pretreatment for the production of ethanol from CGT.However,an increment in the ethanol production is necessary.To accomplish that,this research evaluated the effect of pretreating CGT using alkaline ultrasonication before a liquid hot water and ligninolytic enzymes pretreatments for ethanol production.Three NaOH concentrations(5%,10%,and 15%)were employed for the alkaline ultrasonication.Additionally,this work is one of the first applications of Fourier transform infrared(FT-IR)spectrum and principal component analysis(PCA)as fast methodology to identify the differences in the biomass after different types of pretreatments.Results:The three concentrations employed for the alkaline ultrasonication pretreatment produced ethanol yields and cellulose conversions higher than the experiment without NaOH.Furthermore,15%NaOH concentration achieved twofold increment yield versus the treatment without NaOH.The FT-IR spectrum confirmed modifications in the CGT structure in the different pretreatments.PCA was helpful to determine differences between the pretreated and un-pretreated biomass and to evaluate how the CGT structure changed after each treatment.Conclusions:The combination of alkali ultrasonication hydrolysis,liquid hot water,and ligninolytic enzymes using 15%of NaOH improved 35%the ethanol yield compared with the original treatment.Additionally,we demonstrated the use of PCA to identify the modifications in the biomass structure after different types of pretreatments and conditions.
文摘In this editorial,we comment on the recent article by Fei et al exploring the field of near-infrared spectroscopy(NIRS)research in schizophrenia from a bibliometrics perspective.In recent years,NIRS has shown unique advantages in the auxiliary diagnosis of schizophrenia,and the introduction of bibliometrics has provided a macro perspective for research in this field.Despite the opportunities brought about by these technological developments,remaining challenges require multidi-sciplinary approach to devise a reliable and accurate diagnosis system for schizo-phrenia.Nonetheless,NIRS-assisted technology is expected to contribute to the division of methods for early intervention and treatment of schizophrenia.
文摘This communication looks at the photo-oxidation of polythene and polypropylene plastic bottle tops that are placed on soil in a hot arid environment. The degree of oxidation of the plastic is monitored by FT-IR spectroscopy. It is noted that while different bottle top types photo-oxidize at different rates, all show an appreciable level of oxidation after half a year of exposure to the environment. The oxidation leads to brittleness of the plastic, which leads to fissure formation in bottle tops of little thickness. This leads to fragmentation of the material upon impact, making plastic bottle tops an appreciable source of microplastics.
文摘The adsorption of acetonitrile and its co-adsorption with CO on fresh Mo_2C/Al_2O_3 catalyst have been studied by insitu FT-IR spectroscopy.Linearly adsorbed CH_3CN and CH_3CH_2NH_2 were formed after CH_3CN adsorption on the Mo_2C/ Al_2O_3 catalyst.The appearance of a strong band at 1578 cm^(-1) indicates that CH_3CN was reactive with hydrogen on the Mo_2C/Al_2O_3 catalyst.
基金Major State Basic Research Projects of China(973-2010CB732204)Specific Programs in Graduate Science and Technology Innovation of Beijing Forestry University(BLYJ201110)
文摘In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.
基金the National Natural Science Foundation of China, No.39730160
文摘AIM: To investigate the special Fourier transform infraredspectroscopy (FT-IR) spectra in normal and cancerous tissuesof esophagus.METHODS: Twenty-seven pairs of normal and canceroustissues of esophagus were studied by using FT-IR and thespecial spectra characteristics were analyzed in differenttissues.RESULTS: Different spectra were found in normal andcancerous tissues. The peak at 1 550/cm was weak andwide in cancerous tissues but strong and high in normaltissues.The ratio of I1 647/I1 550 was 2.0 in normal tissuesand 2.36 in cancerous tissues (P＜0.05). The ratio of Ⅰ1 550/I 1 080 was 4.5 in normal tissues and 3.4 in canceroustissues (P＜0.01). The peak at 1453/cm was higher than at1 402/cm in normal tissue and lower than at 1 402/cm incancerous tissues.CONCLUSION: The results indicate that F-FIR may be used in clinical diagnosis.
基金Project supported by the National Natural Science Foundation of China.
文摘A simple method to obtain large red crystals of cytochrome bc1 complex from beef heart mitochondria has been developed. These crystals are very stable. Their shapes are retained for a long time in tip-sealed Pasteur pipets placed in a refrigerator. The structure of crystalline cytochrome bc1 complex by micro FT-IR spectroscopy has been investigated. Based on the IR spectra of cytochrome c, the empirical assignments of the major infrared frequencies of cytochrome bc1 complex are given. Infrared frequencies and relative intensities of variable orientation and section of crystal are significantly different. These imply that infrared spectral characterization of the membrane protein crystallization is associated with the variable symmetries and orientations of the structure. Experimental results show that phospholipid exists in the crystal of cytochrome bc1 complex. The membrane protein is probably spanned on the mitochondrial membrane and buried in phospholipid bilayer in an asymmetric manner.
基金Supported by the Major State Basic Research Development Program( G2 0 0 0 0 7810 2 ) and the National Natural ScienceFoundation of China( No.2 0 0 0 3 0 0 4)
文摘The orientation and structural characterization of the ultrathin film of azobenzene-containing amphiphilic compound, C_ 12AzoNaph(1,4)C_6N +Br -, were studied in the present study. The compound can form a stable monolayer with sodium dextrin sulfate(SDS) by means of electrostatic interaction. Fourier-transform infrared(FT-IR) and near-infrared surface-enhanced Raman scattering(NIR-SERS) spectroscopies were used to study the orientation and characterize the structure of the Langmuir-Blodgett(LB) film and the dipping film. The FT-IR spectra indicate that the alkyl tail is nearly perpendicular to the substrate surface without any aggregation and adopts largely trans-zigzag conformation in the LB film. The NIR-SERS spectra demonstrate that the chromorphoric part in C_ 12AzoNaph(1,4)C_6N +Br is also nearly perpendicular to the surface of silver substrate both in the dipping film and the LB film. A new 'sandwiched system' model was designed to investigate the orientation and structural characterization of the chromophoric part in the multi-monolayer LB films on the non-SERS active substrate. The SERS mechanism of the 'sandwiched system' is discussed in the present paper.
文摘We investigated bleached human hair by FT-IR microspectroscopy and chemical imaging. The cross sectioned hair is approximately 90 μm in diameter, showed cuticle and cortex in chemical imaging. Differential amide I/II absorbance ratio and broadening amide I band between in the cortex and cuticle were confirmed in FT-IR microspectroscopy and chemical imaging. The cystine monoxide band from the products of disulfide oxidation of the amino acid cystine is associated with hair damaging during bleaching process. With increase bleaching time, the band for cystine monoxide shows more intense and larger area in chemical image. The spatially chemical change was investigated in detail by FT-IR microspectroscopy and chemical imaging during the bleached process.
基金support from the Sichuan Science and Technology Program(2019ZDZX0036)the support from the Analytical&Testing Center of Sichuan University.
文摘Laser spectroscopic imaging techniques have received tremendous attention in the-eld of cancer diagnosis due to their high sensitivity,high temporal resolution,and short acquisition time.However,the limited tissue penetration of the laser is still a challenge for the in vivo diagnosis of deep-seated lesions.Nanomaterials have been universally integrated with spectroscopic imaging techniques for deeper cancer diagnosis in vivo.The components,morphology,and sizes of nanomaterials are delicately designed,which could realize cancer diagnosis in vivo or in situ.Considering the enhanced signal emitting from the nanomaterials,we emphasized their combination with spectroscopic imaging techniques for cancer diagnosis,like the surface-enhanced Raman scattering(SERS),photoacoustic,fluorescence,and laser-induced breakdown spectroscopy(LIBS).Applications ofthe above spectroscopic techniques offer new prospectsfor cancer diagnosis.
文摘Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.
基金Supported by The Southwest Medical University Student Innovation and Entrepreneurship Project Fund,No.202310632045 and No.202310632059。
文摘BACKGROUND Compared with current methods used to assess schizophrenia,near-infrared spectroscopy(NIRS)has the advantages of providing noninvasive and real-time monitoring of functional activities of the brain and providing direct and objective assessment information.AIM To explore the research field of NIRS in schizophrenia from the perspective of bibliometrics.METHODS The Web of Science Core Collection was used as the search tool,and the last search date was April 21,2024.Bibliometric indicators,such as the numbers of publications and citations,were recorded.Bibliometrix and VOS viewer were used for visualization analysis.RESULTS A total of 355 articles from 105 journals were included in the analysis.The overall trend of the number of research publications increased.Schizophrenia Research was identified as an influential journal in the field.Kasai K was one of the most influential and productive authors in this area of research.The University of Tokyo and Japan had the highest scientific output for an institution and a country,respectively.The top ten keywords were“schizophrenia”,“activation”,“near-infrared spectroscopy”,“verbal fluency task”,“cortex”,“brain,performance”,“workingmemory”,“brain activation”,and“prefrontal cortex”.CONCLUSION Our study reveals the evolution of knowledge and emerging trends in the field of NIRS in schizophrenia.the research focus is shifting from underlying disease characteristics to more in-depth studies of brain function and physiological mechanisms.
