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Thermodynamic Correlation Between Surface Carboxyl Configuration and Wettability
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作者 GUO Zhuohuan WANG Dayang 《高等学校化学学报》 北大核心 2026年第1期255-266,共12页
In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using at... In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces. 展开更多
关键词 Polyacrylic acid film Hydrogen bonding Attenuated total reflectance fourier-transform infrared spectroscopy Quantitative carboxyl configuration Polar component of surface energy
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The evolving role of Fourier-transform midinfrared spectroscopy in genetic improvement of dairy cattle 被引量:3
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作者 K.M.Tiplady T.J.Lopdell +1 位作者 M.D.Littlejohn D.J.Garrick 《Journal of Animal Science and Biotechnology》 CAS CSCD 2020年第3期626-638,共13页
Over the last 100 years,significant advances have been made in the characterisation of milk composition for dairy cattle improvement programs.Technological progress has enabled a shift from labour intensive,on-farm co... Over the last 100 years,significant advances have been made in the characterisation of milk composition for dairy cattle improvement programs.Technological progress has enabled a shift from labour intensive,on-farm collection and processing of samples that assess yield and fat levels in milk,to large-scale processing of samples through centralised laboratories,with the scope extended to include quantification of other traits.Fourier-transform midinfrared(FT-MIR)spectroscopy has had a significant role in the transformation of milk composition phenotyping,with spectral-based predictions of major milk components already being widely used in milk payment and animal evaluation systems globally.Increasingly,there is interest in analysing the individual FT-MIR wavenumbers,and in utilising the FT-MIR data to predict other novel traits of importance to breeding programs.This includes traits related to the nutritional value of milk,the processability of milk into products such as cheese,and traits relevant to animal health and the environment.The ability to successfully incorporate these traits into breeding programs is dependent on the heritability of the FT-MIR predicted traits,and the genetic correlations between the FT-MIR predicted and actual trait values.Linking FT-MIR predicted traits to the underlying mutations responsible for their variation can be difficult because the phenotypic expression of these traits are a function of a diverse range of molecular and biological mechanisms that can obscure their genetic basis.The individual FT-MIR wavenumbers give insights into the chemical composition of milk and provide an additional layer of granularity that may assist with establishing causal links between the genome and observed phenotypes.Additionally,there are other molecular phenotypes such as those related to the metabolome,chromatin accessibility,and RNA editing that could improve our understanding of the underlying biological systems controlling traits of interest.Here we review topics of importance to phenotyping and genetic applications of FT-MIR spectra datasets,and discuss opportunities for consolidating FT-MIR datasets with other genomic and molecular data sources to improve future dairy cattle breeding programs. 展开更多
关键词 Bovine milk Cattle breeding genetics fourier-transform infrared spectroscopy Trait prediction
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Use of Fourier-transform infrared spectroscopy to rapidly diagnose gastric endoscopic biopsies 被引量:1
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作者 Qing-BoLi Xue-JunSun +5 位作者 Yi-ZhuangXu Li-MinYang Yuan-FuZhang Shi-FuWeng Jing-SenShi Jin-GuangWu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第25期3842-3845,共4页
AIM: To determine if Fourier-transform infrared (FT-IR)spectroscopy of endoscopic biopsies could accurately diagnose gastritis and malignancy.METHODS: A total of 123 gastroscopic samples, including 11 cases of cancero... AIM: To determine if Fourier-transform infrared (FT-IR)spectroscopy of endoscopic biopsies could accurately diagnose gastritis and malignancy.METHODS: A total of 123 gastroscopic samples, including 11 cases of cancerous tissues, 63 cases of chronic atrophic gastritis tissues, 47 cases of chronic superficial gastritis tissues and 2 cases of normal tissues, were obtained from the First Hospital of Xi'an Jiaotong University, China. A modified attenuated total reflectance (ATR) accessory was linked to a WQD-500 FT-IR spectrometer for spectral measurement followed by submission of the samples for pathologic analysis. The spectral characteristics for different types of gastroscopic tissues were summarized and correlated with the corresponding pathologic results.RESULTS: Distinct differences were observed in the FTIR spectra of normal, atrophic gastritis, superficial gastritis and malignant gastric tissues. The sensitivity of FT-IR for detection of gastric cancer, chronic atrophic gastritis and superficial gastritis was 90.9%, 82.5%, 91.5%, and specificity was 97.3%, 91.7%, 89.5% respectively.CONCLUSION: FT-IR spectroscopy can distinguish gastric inflammation from malignancy. 展开更多
关键词 fourier-transform infrared spectroscopy Gastric endoscope Gastric cancer Chronic gastritis Spectral analysis Infrared detection
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Classification of Toxic Cyanobacterial Blooms by Fourier-Transform Infrared Technology (FTIR) 被引量:1
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作者 Gabriel Kenne Deon van der Merwe 《Advances in Microbiology》 2013年第6期1-8,共8页
Cyanobacteria are gram-negative photosynthetic bacteria capable of producing toxins responsible for morbidity and mortality in humans and domestic animals. They are capable of forming concentrated blooms, referred to ... Cyanobacteria are gram-negative photosynthetic bacteria capable of producing toxins responsible for morbidity and mortality in humans and domestic animals. They are capable of forming concentrated blooms, referred to as harmful algal blooms (HABs). Characterization of HABs is necessary to reduce risks from human and animal exposures to toxins. Current methods used to classify cyanobacteria and cyanotoxins have limitations related to time, analyst skills, and cost. Fourier-Transform Infrared Spectroscopy (FTIR) is a potential tool for rapid, robust cyanobacterial classification that is not limited by these factors. To examine the practicality of this method, library screening with default software algorithms was performed on HAB samples, followed by principle component cluster analyses and dendrogram analysis of samples meeting minimum quality requirements. Two tested spectrometers and software packages were successful at distinguishing cyanobacteria from green algae. Principle component cluster analysis and dendrogram analysis also resulted in clear differentiation between cyanobacteria and green algae. While these methods cannot be used independently to fully characterize HABs, they show the potential and practicality of FTIR as a screening tool. 展开更多
关键词 CYANOBACTERIA Harmful ALGAL BLOOM fourier-transform Infrared Spectroscopy
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Optical Frequency Comb-Based Cavity-Enhanced Fourier-Transform Spectroscopy:Application to Collisional Line-Shape Study
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作者 Akiko Nishiyama Grzegorz Kowzan +2 位作者 Dominik Charczun Ryszard S.Trawinski Piotr Mas lowski 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第1期23-30,共8页
Direct-comb spectroscopy techniques uses optical frequency combs(OFCs)as spectroscopic light source.They deliver high sensitivity,high frequency resolution and precision in a broad spectral range.Due to these features... Direct-comb spectroscopy techniques uses optical frequency combs(OFCs)as spectroscopic light source.They deliver high sensitivity,high frequency resolution and precision in a broad spectral range.Due to these features,the field has burgeoned in recent years.In this work we constructed an OFC-based cavity-enhanced Fourier-transform spectrometer in the nearinfrared region and used it for a line-shape study of rovibrational transitions of CO perturbed by Ar.The highly sensitive measurements spanned the wavenumber range from 6270 cm^-1 to 6410 cm^-1,which covered both P and R branch of the second overtone band of CO.The spectrometer delivers high-resolution surpassing the Fourier-transform resolution limit determined by interferogram length,successfully removing ringing and broadening effects caused by instrumental line shape function.The instrumental-line-shape-free method and high signal-to-noise ratio in the measurement allowed us to observe collisional effects beyond those described by the Voigt profile.We retrieved collisional line-shape parameters by fitting the speed-dependent Voigt profile and found good agreement with the values given by precise cavity ring-down spectroscopy measurements that used a continuous-wave laser referenced to a stabilized OFC.The results demonstrate that OFC-based cavity-enhanced Fouriertransform spectroscopy is a strong tool for accurate line-shape studies that will be crucial for future spectral databases. 展开更多
关键词 Carbon monoxide Spectral lineshapes Optical frequency comb Cavity enhanced absorption spectroscopy fourier-transform spectroscopy
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Promotional roles of ZrO_2 and WO_3 in V_2O_5-WO_3/TiO_2-ZrO_2 catalysts for NO_x reduction by NH_3:Catalytic performance,morphology,and reaction mechanism 被引量:8
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作者 张亚平 王龙飞 +4 位作者 李娟 张会岩 徐海涛 肖睿 杨林军 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第11期1918-1930,共13页
V2O5/TiO2-ZrO2 catalysts containing various amounts of WO3 were synthesized.The catalyst morphologies,catalytic performances,and reaction mechanisms in the selective catalytic reduction of NOx by NH3 were investigated... V2O5/TiO2-ZrO2 catalysts containing various amounts of WO3 were synthesized.The catalyst morphologies,catalytic performances,and reaction mechanisms in the selective catalytic reduction of NOx by NH3 were investigated using in situ diffuse-reflectance infrared Fourier-transform spectroscopy,temperature-programmed reduction(TPR),X-ray diffraction,and the Brunauer-Emmett-Teller(BET) method.The BET surface area of the triple oxides increased with increasing ZrO2 doping but gradually decreased with increasing WO3 loading.Addition of sufficient WO3 helped to stabilize the pore structure and the combination of WO3 and ZrO2 improved dispersion of all the metal oxides.The mechanisms of reactions using V2O5-9%WO3/TiO2-ZrO2 and V2O5-9%WO3/TiO2were compared by using either a single or mixed gas feed and various pretreatments.The results suggest that both reactions followed the Eley-Ridel mechanism;however,the dominant acid sites,which depended on the addition of WO3 or ZrO2,determined the pathways for NOx reduction,and involved[NH4^+-NO-Bronsted acid site]^* and[NH2-NO-Lewis acid site]^* intermediates,respectively.NH3-TPR and H2-TPR showed that the metal oxides in the catalysts were not reduced by NH3 and O2did not reoxidize the catalyst surfaces but participated in the formation of H2O and NO2. 展开更多
关键词 ZIRCONIA Tungsten oxide Selective catalytic reduction by ammonia In situ infrared diffuse-reflectance fourier-transform spectroscopy Reaction mechanism
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Application of Cosine Zone Plates to Image Encryption
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作者 葛凡 陈林飞 赵道木 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第8期2863-2865,共3页
We analyse the diffraction result of optical field after Cosine zone plate, and theoretically deduce its transform matrix. Under some conditions, its diffraction distribution is a mixture of fractional Fourier spectra... We analyse the diffraction result of optical field after Cosine zone plate, and theoretically deduce its transform matrix. Under some conditions, its diffraction distribution is a mixture of fractional Fourier spectra. Then we use Cosine zone plate and its diffraction result to image encryption. Possible optical image encryption and decryption implementations are proposed, and some numerical simulation results are also provided. 展开更多
关键词 FRACTIONAL fourier-transforms DIGITAL HOLOGRAPHY OPTICAL IMPLEMENTATION DOMAIN WAVELENGTH OBJECT
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中国首个地基高分辨率傅里叶变换光谱观测站的大气成分长期观测研究 被引量:5
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作者 刘诚 孙友文 +7 位作者 单唱功 王薇 Justus Notholt Mathias Palm 殷昊 田园 高吉熹 毛慧琴 《Engineering》 SCIE EI CAS CSCD 2023年第3期201-214,共14页
长期观测主要大气成分的体积混合比(VMR)廓线和柱总量对掌握中国气候变化和碳收支具有重要意义。本文对我国首个TCCON高分辨率傅里叶变换光谱(FTS)地基观测站——合肥观测站开展了系统性研究,该观测站可观测30多种大气成分的柱总量和VM... 长期观测主要大气成分的体积混合比(VMR)廓线和柱总量对掌握中国气候变化和碳收支具有重要意义。本文对我国首个TCCON高分辨率傅里叶变换光谱(FTS)地基观测站——合肥观测站开展了系统性研究,该观测站可观测30多种大气成分的柱总量和VMR廓线。本文公布了2014年以来合肥观测站观测到的部分关键大气成分的时间序列,总结了迄今为止该站点取得的主要研究成果,包括光谱反演表征和归一化、关键大气成分的总体演变特征、排放估计、卫星和化学传输模式(CTM)校验以及对大气污染来源和传输的相关研究。同时,本文还对合肥观测站的观测、科学研究和未来研究计划进行了展望。中国明确提出2030年二氧化碳排放达到峰值,2060年实现碳中和。合肥观测站将为中国政府制定绿色经济政策、实现碳中和及《巴黎协定》目标提供科学支撑。 展开更多
关键词 Remote sensing fourier-transform Atmospheric pollution Greenhouse gases Climate change
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Forsterite Nanopowder:Structural Characterization and Biocompatibility Evaluation 被引量:3
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作者 M.A.Naghiu M.Gorea +2 位作者 E.Mutch F.Kristaly M.Tomoaia-Cotisel 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2013年第7期628-632,共5页
Forsterite, a new biocompatible material was synthesized from Mg(NO3)2.6H20 and TEOS by using the sol-gel method. The material was then heated at 800, 900 and 1000 ℃. The forsterite was noticed as the main crystall... Forsterite, a new biocompatible material was synthesized from Mg(NO3)2.6H20 and TEOS by using the sol-gel method. The material was then heated at 800, 900 and 1000 ℃. The forsterite was noticed as the main crystalline phase in the material fired at 900 and 1000 ℃, while periclase (MgO) was present in all the samples. The tests confirm that in the first two samples forsterite is present as crystallites 〈60 nm, while in the sample synthesized at 1000 ℃ it forms aggregates of micrometre-sized grains. In vitro test was performed by immersing the forsterite powder in the simulating body fluids (SBF) and hydroxyapatite formation on the surface was investigated. We could evidence the formation of hydroxyapatite on the forsterite surface after 7 days of immersion. The MTT test confirmed that forsterite powders dissolution promote osteoblast proliferation of the human-type osteoblasts with no significant cytotoxicity effects. 展开更多
关键词 FORSTERITE Nano particles BIOCOMPATIBILITY Grain size fourier-transform infrared (FTIR) spectroscopy
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Removal and transformation of dissolved organic matter in secondary effluent during granular activated carbon treatment 被引量:3
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作者 Liang-liang WEI Qing-liang ZHAO +1 位作者 Shuang XUE Ting JIA 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第7期994-1003,共10页
This paper focused on the removal and transformation of the dissolved organic matter (DOM) in secondary effluent during the granular activated carbon (GAC) treatment. Using XAD-8/XAD-4 resins, DOM was fractionated... This paper focused on the removal and transformation of the dissolved organic matter (DOM) in secondary effluent during the granular activated carbon (GAC) treatment. Using XAD-8/XAD-4 resins, DOM was fractionated into five classes: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N) and hydrophilic fraction (HPI). Subsequently, the water quality parameters of dissolved organic carbon (DOC), absorbance of ultraviolet light at 254 nm (UV-254), specific ultraviolet light absorbance (SUVA) and trihalomethane formation potential (THMFP) were analyzed for the unfractionated and fractionated water samples. The results showed that the order of the DOC removal with respect to DOM fractions was observed to be HPI〉HPO-A〉HPO-N〉TPI-A〉TPI-N. During the GAC treatment, the THMFP of the unfractionated water samples decreased from 397.4 μg/L to 176.5 μg/L, resulting in a removal efficiency of 55.6%. The removal order of the trilaalomethanes (THMs) precursor was as follows: HPO-A〉TPI-A〉TPI-N〉HPO-N〉HPI. By the GAC treatment, the specific THMFP of HPO-A, TPI-A, TPI-N and the original unfractionated water samples had a noticeable decrease, while that of HPO-N and HPI showed a converse trend. The Fourier transform infrared (FTIR) results showed that the hydroxide groups, carboxylic acids, aliphatic C-H were significantly reduced by GAC treatment. 展开更多
关键词 Dissolved organic matter (DOM) FRACTIONATION Trihalomethane formation potential (THMFP) Specific THMFP fourier-transform infrared (FTIR)
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The quantum spectra analysis of the circular billiards in wells 被引量:2
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作者 张延惠 张丽琴 +3 位作者 徐学友 葛美华 林圣路 杜孟利 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第3期502-506,共5页
We use a recently defined quantum spectral function and apply the method of closed-orbit theory to the 2D circular billiard system. The quantum spectra contain rich information of all classical orbits connecting two a... We use a recently defined quantum spectral function and apply the method of closed-orbit theory to the 2D circular billiard system. The quantum spectra contain rich information of all classical orbits connecting two arbitrary points in the well. We study the correspondence between quantum spectra and classical orbits in the circular, 1/2 circular and 1/4 circular wells using the analytic and numerical methods. We find that the peak positions in the Fourier- transformed quantum spectra match accurately with the lengths of the classical orbits. These examples show evidently that semi-classlcal method provides a bridge between quantum and classical mechanics. 展开更多
关键词 circular billiard closed-orbit theory quantum spectra function fourier-transformed spectra
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Introducing a Novel Approach for Oil-Oil Correlation based on Asphaltene Structure: X-ray Diffraction 被引量:2
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作者 Zahra SADEGHTABAGHI Ahmad Reza RABBANI Abdolhossein HEMMATI-SARAPARDEH 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第6期2100-2119,共20页
Asphaltenes have always been an attractive subject for researchers.However,the application of this fraction of the geochemical field has only been studied in a limited way.In other words,despite many studies on asphal... Asphaltenes have always been an attractive subject for researchers.However,the application of this fraction of the geochemical field has only been studied in a limited way.In other words,despite many studies on asphaltene structure,the application of asphaltene structures in organic geochemistry has not so far been assessed.Oil-oil correlation is a wellknown concept in geochemical studies and plays a vital role in basin modeling and the reconstruction of the burial history of basin sediments,as well as accurate characterization of the relevant petroleum system.This study aims to propose the Xray diffraction(XRD)technique as a novel method for oil-oil correlation and investigate its reliability and accuracy for different crude oils.To this end,13 crude oil samples from the Iranian sector of the Persian Gulf region,which had previously been correlated by traditional geochemical tools such as biomarker ratios and isotope values,in four distinct genetic groups,were selected and their asphaltene fractions analyzed by two prevalent methods of XRD and Fouriertransform infrared spectroscopy(FTIR).For oil-oil correlation assessment,various cross-plots,as well as principal component analysis(PCA),were conducted,based on the structural parameters of the studied asphaltenes.The results indicate that asphaltene structural parameters can also be used for oil-oil correlation purposes,their results being completely in accord with the previous classifications.The average values of distance between saturated portions(d_(r))and the distance between two aromatic layers(d_(m))of asphaltene molecules belonging to the studied oil samples are 4.69Aand 3.54A,respectively.Furthermore,the average diameter of the aromatic sheets(L_(a)),the height of the clusters(L_(c)),the number of carbons per aromatic unit(C_(au)),the number of aromatic rings per layer(R_(a)),the number of sheets in the cluster(M_(e))and aromaticity(f_(a))values of these asphaltene samples are 10.09A,34.04A,17.42A,3.78A,10.61Aand 0.26A,respectively.The results of XRD parameters indicate that plots of dr vs.d_(m),d_(r) vs.M_(e),d_(r) vs.f_(a),d_(m) vs.L_(c),L_(c) vs.L_(a),and f_(a) vs.L_(a) perform appropriately for distinguishing genetic groups.A comparison between XRD and FTIR results indicated that the XRD method is more accurate for this purpose.In addition,decision tree classification,one of the most efficacious approaches of machine learning,was employed for the geochemical groups of this study for the first time.This tree,which was constructed using XRD data,can distinguish genetic groups accurately and can also determine the characteristics of each geochemical group.In conclusion,the obtaining of structural parameters for asphaltene by the XRD technique is a novel,precise and inexpensive method,which can be deployed as a new approach for oil-oil correlation goals.The findings of this study can help in the prompt determination of genetic groups as a screening method and can also be useful for assessing oil samples affected by secondary processes. 展开更多
关键词 oil-oil correlation petroleum characterization X-ray diffraction fourier-transform infrared spectroscopy decision tree classification
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Optical high-resolution spectroscopic study of Tm^(3+) crystal-field levels in LiLuF_4 被引量:2
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作者 D.S.Pytalev S.A.Klimin M.N.Popova 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第4期624-626,共3页
We report on the fast high-resohition study of LiLuF4:Tm3+. The accurate energy level scheme of Tm3+ in the LiLuF4 matrix was obtained for the 3H6.5.4, 3F4.3.2, and ^1G4 multiplets. It was shown that electric-dipol... We report on the fast high-resohition study of LiLuF4:Tm3+. The accurate energy level scheme of Tm3+ in the LiLuF4 matrix was obtained for the 3H6.5.4, 3F4.3.2, and ^1G4 multiplets. It was shown that electric-dipole transitions dominate for all the studied multiplets except the 3H5 one. 展开更多
关键词 fourier-transform spectroscopy Tm^3+ crystal-field levels LiLuF4 rare earths
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Phase-Space Analysis of Wavefront Coding Imaging Systems 被引量:1
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作者 阳庆国 孙建锋 刘立人 《Chinese Physics Letters》 SCIE CAS CSCD 2006年第8期2080-2083,共4页
We explore the use of the Radon-Wigner transform, which is associated with the fractional Fourier transform of the pupil function, for determining the point spread function (PSF) of an incoherent defocused optical s... We explore the use of the Radon-Wigner transform, which is associated with the fractional Fourier transform of the pupil function, for determining the point spread function (PSF) of an incoherent defocused optical system. Then we introduce these phase-space tools to analyse the wavefront coding imaging system. It is shown that the shape of the PSF for such a system is highly invariant to the defocus-related aberrations except for a lateral shift. The optical transfer function of this system is also investigated briefly from a new understanding of ambiguity function. 展开更多
关键词 FRACTIONAL fourier-transform WIGNER DISTRIBUTIONS OPTICS
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Probing active species for CO hydrogenation over ZnCr_(2)O_(4) catalysts 被引量:1
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作者 Yunjian Ling Yihua Ran +7 位作者 Weipeng Shao Na Li Feng Jiao Xiulian Pan Qiang Fu Zhi Liu Fan Yang Xinhe Bao 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第8期2017-2025,共9页
Oxide catalysts are increasingly employed for hydrogenation reactions,among which ZnCrOx is a major catalyst for the oxide-zeolite(OXZEO)process and for the hydrogenation of C1 molecules in general.Owing to the comple... Oxide catalysts are increasingly employed for hydrogenation reactions,among which ZnCrOx is a major catalyst for the oxide-zeolite(OXZEO)process and for the hydrogenation of C1 molecules in general.Owing to the complex nature of ternary oxides,the surface and catalytic properties of ZnCr_(2)O_(4) spinel have remained controversial for CO hydrogenation.Combining in-situ Fourier-transformed infrared spectroscopy and X-ray photoelectron spectroscopy,we examined the adsorption and reaction of CO/H_(2) on the ZnCr_(2)O_(4) catalysts,which were pre-treated under oxidative or reductive conditions.The reduced ZnCr_(2)O_(4) catalyst was found to expose more surface sites for CO adsorption/reaction than the oxidized ZnCr_(2)O_(4) catalyst.Exposing the reduced ZnCr_(2)O_(4) to H_(2) at room temperature led to the formation of surface hydride species,which would transform into hydroxyl species at elevated temperatures.The reduced ZnCr_(2)O_(4) surface exhibited much stronger interaction with CO and H_(2) than ZnO and Cr_(2)O_(3).Exposing the reduced ZnCr_(2)O_(4) to the CO and H_(2)(1:1)mixture gas led to the hydrogenation of CO.However,CO was oxidized by the hydroxyl species via the water-gas-shift reaction,whereas the hydrogenation of CO could only be achieved by surface hydride species on the reduced ZnCr_(2)O_(4) to formyl or formate species at 373-473 K.Our study has thus shed light on the active species that control elementary reaction process of CO hydrogenation on complex oxide surfaces. 展开更多
关键词 ZnCr_(2)O_(4) fourier-transformed infrared spectroscopy CO adsorption HYDRIDE HYDROXYL
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Spectroscopy of compounds from the family of rare-earth orthoborates 被引量:1
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作者 Marina N.Popova 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第4期607-611,共5页
This paper is devoted to the rare-earth borates described by the general formula RM3(BO3)4, M = Al, Fe, and Cr, that have non-centrosymmetric trigonal slructure of the natural mineral huntite. It give a brief review... This paper is devoted to the rare-earth borates described by the general formula RM3(BO3)4, M = Al, Fe, and Cr, that have non-centrosymmetric trigonal slructure of the natural mineral huntite. It give a brief review of a spectroscopic research on YbAI3(BO3)4 (YbAB), on a large group of magnetic iron borates, and on NdCra(BO3)4. 展开更多
关键词 YbAl3(BO3)4 rare-earth iron and chromium borates magnetic ordering fourier-transform optical spectroscopy
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Effect of metal fluorides on chromium ions doped bismuth borate glasses for optical applications
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作者 L Haritha K Chandra Sekhar +3 位作者 R Nagaraju G Ramadevudu Vasanth G Sathe Md.Shareefuddin 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第3期366-372,共7页
Fluoride based glasses with composition CaF_2-ZnF_2-Bi_2 O_3-B_2 O_3 doped with chromium ions have been investigated using physical, optical, electron paramagnetic resonance(EPR), Fourier-transform infrared spectrosco... Fluoride based glasses with composition CaF_2-ZnF_2-Bi_2 O_3-B_2 O_3 doped with chromium ions have been investigated using physical, optical, electron paramagnetic resonance(EPR), Fourier-transform infrared spectroscopy(FTIR), and Raman studies. The amorphous nature of samples was confirmed from x-ray diffraction spectra. The density is evaluated from the Archimedes principle and the values of optical band gap and Urbach energy values were evaluated from the optical absorption spectra. Thus, molar volume, refractive index, etc., were also evaluated. The observed decrease in density and the optical band gap with CaF2 is explained using the crystalline density of metal fluorides and the ionicity of fluorine ions,respectively. The three peaks near 450 nm, 606 nm, and 720 nm, which are shown in the absorption spectra, are accredited to ~4 A)(2 g) → ~4 T_(1 g), ~4 A_(2 g)→ ~4 T_(2 g), ~4 A_(2 g)→~2 E transitions, respectively. Resonance signals at g≈ 4.82 and g≈ 1.99 were observed in EPR spectra which are assigned. FTIR and Raman analysis were carried out to examine the impact of metal fluorides on the structure of bismuth borate glasses. 展开更多
关键词 GLASSES x-ray diffraction electron PARAMAGNETIC resonance fourier-transform infrared spectroscopy(FTIR) RAMAN spectra
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Optical Image Encryption with Simplified Fractional Hartley Transform
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作者 李新新 赵道木 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第7期2477-2480,共4页
We present a new method for image encryption on the basis of simplifed fractional Hartley transform (SFRHT). SFRHT is a real transform as Hartley transform (HT) and furthermore, superior to HT in virtue of the adv... We present a new method for image encryption on the basis of simplifed fractional Hartley transform (SFRHT). SFRHT is a real transform as Hartley transform (HT) and furthermore, superior to HT in virtue of the advantage that it can also append fractional orders as additional keys for the purpose of improving the system security to some extent. With this method, one can encrypt an image with an intensity-only medium such as a photographic film or a CCD camera by spatially incoherent or coherent illumination. The optical realization is then proposed and computer simulations are also performed to verify the feasibility of this method. 展开更多
关键词 fourier-transform DIGITAL HOLOGRAPHY FRESNEL DOMAIN IMPLEMENTATION
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Integrated phase unwrapping algorithm for the measurement of 3D shapes by Fourier transform profilometry
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作者 Shuang-qing WU Yin ZHANG +1 位作者 San-yuan ZHANG Xiu-zi YE 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第7期1018-1028,共11页
An integrated and reliable phase unwrapping algorithm is proposed based on residues and blocking-lines detection, closed contour extraction and quality map ordering for the measurement of 3D shapes by Fourier-transfor... An integrated and reliable phase unwrapping algorithm is proposed based on residues and blocking-lines detection, closed contour extraction and quality map ordering for the measurement of 3D shapes by Fourier-transform profilometry (FTP). The proposed algorithm first detects the residues on the wrapped phase image, applies wavelet analysis to generate the blocking-lines that can just connect the residues of opposite polarity, then carries out the morphology operation to extract the closed contour of the shape, and finally uses the modulation intensity information and the Laplacian of Gaussian operation of the wrapped phase image as the quality map. The unwrapping process is completed from a region of high reliability to that of low reliability and the blocking-lines can prevent the phase error propagation effectively. Furthermore, by using the extracted closed contour to exclude the invalid areas from the phase unwrapping process, the algorithm becomes more efficient. The experiment shows the effec-tiveness of the new algorithm. 展开更多
关键词 fourier-transform profilometry (FTP) Phase unwrapping RESIDUES Blocking-lines Laplacian of Gaussian Modulation intensity
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Tm^(3+) interactions in LiYF_4 studied by high-resolution spectroscopy
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作者 S.A.Klimin D.S.Pytalev 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第4期633-636,共4页
We used the high-resolution spectroscopy to study the interactions that Tm3+ ion in a LiYF4 crystal is subjected to. Several crystal field transitions with low integral intensity were found not registered before by m... We used the high-resolution spectroscopy to study the interactions that Tm3+ ion in a LiYF4 crystal is subjected to. Several crystal field transitions with low integral intensity were found not registered before by means of ordinary spectroscopy. Spectral evidences for interionic, hyperfine, isotopic interactions, and for a resonant broadening of the ground state are presented. 展开更多
关键词 high-resolution fourier-transform speclroscopy hyperfme structure isotopic structure pair centers rare earths
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