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A low-noise X-band microwave source with digital automatic frequency control for electron paramagnetic resonance spectroscopy
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作者 贺羽 康润琪 +1 位作者 石致富 荣星 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期46-51,共6页
We report a new design of microwave source for X-band electron paramagnetic resonance spectrometer.The microwave source is equipped with a digital automatic frequency control circuit.The parameters of the digital auto... We report a new design of microwave source for X-band electron paramagnetic resonance spectrometer.The microwave source is equipped with a digital automatic frequency control circuit.The parameters of the digital automatic frequency control circuit can be flexibly configured for different experimental conditions,such as the input powers or the quality factors of the resonator.The configurability makes the microwave source universally compatible and greatly extends its application.To demonstrate the ability of adapting to various experimental conditions,the microwave source is tested by varying the input powers and the quality factors of the resonator.A satisfactory phase noise as low as-135 d Bc/Hz at 100-k Hz offset from the center frequency is achieved,due to the use of a phase-locked dielectric resonator oscillator and a direct digital synthesizer.Continuous-wave electron paramagnetic resonance experiments are conducted to examine the performance of the microwave source.The outstanding performance shows a prospect of wide applications of the microwave source in numerous fields of science. 展开更多
关键词 electron paramagnetic resonance X-BAND microwave source automatic frequency control
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Temperature-Dependent Formation of Redox Sites in Molybdenum Trioxide Studied by Electron Paramagnetic Resonance Spectroscopy
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作者 谭天 陈明 +1 位作者 苏吉虎 杜江峰 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第6期657-660,I0002,共5页
The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature depend... The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO3 was surveyed at the range of 350℃ to 750℃. Upon reduction, the formed redox species characterized by EPR spectroscopy are the MoVion and superoxide anion radical (O2-) when the reduction was induced at the optimal temperature of 300-350℃. When heating-up from 350℃, the EPR signals started to decline in amplitude. The signals in the range of 400-450℃ decreased to half of that at 350℃, and then to zero at ~600℃. Further treatment at even higher temperature or prolonged heating time at 500℃ caused more reduction and more free electrons were released to the MoO3 bulk, which results in a delocalized means similar to the antiferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts. 展开更多
关键词 MOO3 Thermal reduction Mo~Ⅴ Superoxide anion radical electron paramagnetic resonance spectroscopy
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Identification of Superoxide O2^- during KNO3-NaNO2-NaNO3 Salt by Electron UV-Vis Absorption Spectroscopy Thermal Decomposition of Molten Paramagnetic Resonance and
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作者 刘舒婷 苏涛 +2 位作者 张鹏 费泽杰 刘洪涛 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第4期372-378,I0001,共8页
On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal sta... On account of excellent thermal physical properties, molten nitrates/nitrites salt has been widely employed in heat transfer and thermal storage industry, especially in concentrated solar power system. The thermal stability study of molten nitrate/nitrite salt is of great importance for this system, and the decomposition mechanism is the most complicated part of it. The oxide species O2^2- and O2^- were considered as intermediates in molten KNO3-NaNO3 while hard to been detected in high temperature molten salt due to their trace concentration and low stability. In this work, the homemade in situ high temperature UV- Vis instrument and a commercial electron paramagnetic resonance were utilized to supply evidence for the formation of superoxide during a slow decomposition process of heat transfer salt (HTS, 53 wt% KNO3/40 wt% NaNO2/7 wt% NaNO3). It is found that the superoxide is more easily generated from molten NaNO2 compared to NaNO3, and it has an absorption band at 420-440 nm in HTS which red shifts as temperature increases. The band is assigned to charge-transfer transition in NaO2 or KO2, responsible for the yellow color of the molten nitrate/nitrite salt. Furthermore, the UV absorption bands of molten NaNO2 and NANO3 are also obtained and compared with that of HTS. 展开更多
关键词 Superoxide Decomposition of heat transfer salt High temperature UV-visible electron paramagnetic resonance
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Electron paramagnetic resonance study of amphiphiles partitioning behavior in desiccation-tolerant moss during dehydration 被引量:3
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作者 Shu Jun Xu Wei Hong Chen +2 位作者 Ying Wen Chen Cui Fang Wang Yan Wang 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第7期865-868,共4页
Desiccation tolerance is a crucial characteristic for desert moss surviving in arid regions. Desiccation procedure always induces amphiphiles transferring from the polar cytoplasm into lipid bodies. The behavior of am... Desiccation tolerance is a crucial characteristic for desert moss surviving in arid regions. Desiccation procedure always induces amphiphiles transferring from the polar cytoplasm into lipid bodies. The behavior of amphiphiles transferring can contribute to the enhancement of desiccation tolerance and the reduction of plasma membrane integrity simultaneously. The effects of amphiphiles partitioning into the lipid phase during water loss has been studied for pollen and seeds using electron paramagnetic resonance (EPR) spectroscopy. However, desiccation-tolerant high plants occur among mosses, several angiosperms and higher plants seeds or pollens. They have different strategies for survival in dehydration and rehydration. A desiccation-tolerant moss Tortula desertorurn was used to investigate the behaviors of amphiphilic molecules during drying by spin label technology. There are small amount of amphiphilic probes partitioning into membrane during moss leaves dehydration, comparing with that in higher plants. Cytoplasm viscosity changed from 1.14 into glass state only dehydration less than 60 min. Moss leaves lost plasma membrane integrity slightly,from 0.115 to 0.237, occurred simultaneously with amphiphiles partition. The results showed the more advantages of mosses than higher plants in adapting fast dehydration. We propose that EPR spin label is feasible for studying the amphiphiles partitioning mechanisms in membrane protection and damage for desiccation-tolerant mosses. 展开更多
关键词 Plasma membrane permeability Amphiphiles partition Desiccation tolerance electron paramagnetic resonance Tortula desertorum broth. MOSSES
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Electron paramagnetic resonance studies of the chelate-based ionic liquid in different solvents 被引量:3
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作者 Songna Zhang Xinyu Wang +1 位作者 Jia Yao Haoran Li 《Green Energy & Environment》 SCIE CSCD 2020年第3期341-346,共6页
The electron paramagnetic resonance spectra of the chelate-based ionic liquid[C_(10)mim][Cu(F_6-acac)_3]in different solvents have been obtained at 120 K.It was found that the values of the^(63)Cu hyperfine coupling c... The electron paramagnetic resonance spectra of the chelate-based ionic liquid[C_(10)mim][Cu(F_6-acac)_3]in different solvents have been obtained at 120 K.It was found that the values of the^(63)Cu hyperfine coupling constants(A_(IL))of[C_(10)mim][Cu(F_6-acac)_3]in molecular solvents were from 116 to 180 Gauss.Moreover,the A_(IL)values in general ionic liquids are more complicated,and two sets of peaks can often be observed in their electron paramagnetic resonance spectra.Based on the Kamlet-Taft parameters,relative permittivity,the experimental results were discussed in terms of solvation effect and coordination of the solvents. 展开更多
关键词 Chelate-based ionic liquid Probe electron paramagnetic resonance spectra Solvents
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Electron paramagnetic resonance characterization of aluminum ion implantation-induced defects in 4H-SiC 被引量:1
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作者 Xiuhong Wang Zongwei Xua +4 位作者 Mathias Rommel Bing Dong Le Song Clarence Augustine TH Tee Fengzhou Fang 《Nanotechnology and Precision Engineering》 EI CAS CSCD 2019年第4期157-162,共6页
Deep-level defects in silicon carbide(SiC)are critical to the control of the performance of SiC electron devices.In this paper,deep-level defects in aluminumion-implanted 4H-SiC after high-temperature annealingwere st... Deep-level defects in silicon carbide(SiC)are critical to the control of the performance of SiC electron devices.In this paper,deep-level defects in aluminumion-implanted 4H-SiC after high-temperature annealingwere studied using electron paramagnetic resonance(EPR)spectroscopy at temperatures of 77 K and 123 K under different illumination conditions.Results showed that the main defect in aluminum ion-implanted 4H-SiC was the positively charged carbon vacancy(VC+),and the higher the doping concentration was,the higher was the concentration of VC+.Itwas found that the type of material defectwas independent of the doping concentration,although more VC+defects were detected during photoexcitation and at lower temperatures.These results should be helpful in the fundamental research of p-type 4H-SiC fabrication in accordance with functional device development. 展开更多
关键词 electron paramagnetic resonance Silicon carbide DEFECTS Carbon vacancy
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X-Ray Diffraction, Electron Paramagnetic Resonance and Optical Absorption Study of Bauxite 被引量:1
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作者 Tanguturi Ravindra Reddy Krishnan Thyagarajan +2 位作者 Ovidio Almanza Montero Sanapa Reddy Lakshmi Reddy Tamio Endo 《Journal of Minerals and Materials Characterization and Engineering》 2014年第2期114-120,共7页
The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be g... The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques. 展开更多
关键词 BAUXITE GIBBSITE X-Ray Diffraction (XRD) electron paramagnetic electron paramagnetic resonance Optical Absorption Spectra FE3+ Water Fundamentals
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Electron Paramagnetic Resonance and Optical Absorption Studies on Copper Ions in Mixed Alkali Cadmium Phosphate Glasses
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作者 G. Giridhar M. Rangacharyulu +1 位作者 R.V.S.S.N. Ravikumar P. Sambasiva Rao 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2009年第4期531-534,共4页
Electron paramagnetic resonance (EPR) and optical absorption studies were carried out at room temperature on copper doped mixed alkali cadmium phosphate (LiNaCdP) glasses to understand the nature and symmetry of d... Electron paramagnetic resonance (EPR) and optical absorption studies were carried out at room temperature on copper doped mixed alkali cadmium phosphate (LiNaCdP) glasses to understand the nature and symmetry of dopant. Three samples with varying concentrations of alkali ions have been prepared. The spin Harniltonian parameters obtained from room temperature EPR spectra are: gli=2.437, 9⊥=2.096, A‖=117×10-4 cm-1, A⊥=26×10-4 cm-1 for LiNaCdP1, g‖=2.441, g⊥=2.088, A‖=121×10-4 cm-1, A⊥=25×10-4 cm-1 for LiNaCdP2and g‖=2.433,g⊥=2.096, A‖=125×10 4cm-1, A⊥=32×10-4cm-1 for LiNaCdP3. TheseEPR results indicate that the dopant Cu2+ ion enters the glass matrix into a tetragonally elongated octahedral site. The bonding parameters evaluated by correlating optical and EPR data suggest that bonding between the central metal ion and ligands is partially covalent. The mixed alkali effect in cadmium phosphate glasses was reported. 展开更多
关键词 GLASSES electron paramagnetic resonance (EPR) Optical properties
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Effect of local structure on electron paramagnetic resonance spectra for trigonal [Cr(H_2O)_6]^(3+) coordination complex in the sulfate alums series:a ligand field theory study
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作者 李艳芳 邝小渝 +2 位作者 高明亮 赵亚儒 王怀谦 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第7期2967-2974,共8页
A simple theoretical method is introduced for studying the interrelation between electronic and molecular structures.By diagonalizing the 120 × 120 complete energy matrices,the relationships between zero-field sp... A simple theoretical method is introduced for studying the interrelation between electronic and molecular structures.By diagonalizing the 120 × 120 complete energy matrices,the relationships between zero-field splitting (ZFS) parameter D and local distortion parameter △θ for Cr^3+ ions doped,separately,in α- and β- alums are investigated.Our results indicate that there exists an approximately linear relationship between D and △θ in a temperature range 4.2-297 K and the signs of D and △θ are opposite to each other.Moreover,in order to understand the contribution of spin-orbit coupling coefficient ζ to ZFS parameter D,the relation between D and ζ is also discussed. 展开更多
关键词 complete energy matrices electron paramagnetic resonance (EPR) spectra local structure
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Theoretical Studies of Electron Paramagnetic Resonance Parameters for Cr^4+ Ions in Ca2GeO4 Crystals
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作者 WUXiao-Xuan ZHENGWen-Chen MEIYang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期337-340,共4页
The electron paramagnetic resonance (EPR) parameters (zero-Geld splitting Dand g factors g_‖, g_⊥) of Cr~(4+) ions in Ca_2 GeO_4 crystals have been calculated from thecomplete high-order perturbation formulas of EPR... The electron paramagnetic resonance (EPR) parameters (zero-Geld splitting Dand g factors g_‖, g_⊥) of Cr~(4+) ions in Ca_2 GeO_4 crystals have been calculated from thecomplete high-order perturbation formulas of EPR parameters for a 3d~2 ion in trigonal MX_4clusters. In these formulas, in addition to the contributions to EPR parameters from the widely usedcrystal-field (CF) mechanism, the contributions from the charge-transfer (CT) mechanism (which areoften neglected) are included. From the calculations, it is found that for the high valence state3d~n ions in crystals, the reasonable explanation of EPR parameters (in particular, the g factors)should take both the CF and CT mechanisms into account. 展开更多
关键词 crystal- and ligand-field theory electron paramagnetic resonance charge-transfer mechanism optical spectroscopy tunable laser crystal
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Monitoring the autoproteolysis of hiv-1 protease by site-directed spin-labeling and electron paramagnetic resonance spectroscopy
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作者 Jamie L. Kear Luis Galiano +2 位作者 Angelo M. Veloro Laura S. Busenlehner Gail E. Fanucci 《Journal of Biophysical Chemistry》 2011年第2期137-146,共10页
Site-directed spin-labeling with continuous wave electron paramagnetic resonance spectroscopy was used to monitor autoproteolysis of HIV-1 protease, an enzyme essential for viral maturation. Two protein constructs wer... Site-directed spin-labeling with continuous wave electron paramagnetic resonance spectroscopy was used to monitor autoproteolysis of HIV-1 protease, an enzyme essential for viral maturation. Two protein constructs were examined, namely subtype F and the circulating recombinant form CRF01_A/E. As the protease undergoes self-cleavage, protein unfolds and small peptide fragments containing the spin label are generated, which collectively give rise to a sharp spectral component that is easily discernable in the high-field resonance line in the EPR spectrum. By monitoring the intensity of this spectral component over time, the autoproteolytic stability of each construct was characterized under various conditions. Data were collected for samples stored at 4 °C, 25 °C, and 37 °C, and on a subtype F HIV-1 protease sample stored at 25 °C and containing the FDA-approved protease inhibitor Tipranavir. As expected, the rate of autoproteolysis decreased as the storage temperature was lowered. Minimal autoproteolysis was seen for the sample that contained Tipranavir, providing direction for future spectroscopic studies of active protease samples. When compared to standard methods of monitoring protein degradation such as gel electrophoresis or chromatographic analyses, spin-labeling with CW EPR offers a facile, real-time, non-consuming way to monitor autoproteolysis or protein degradation. Additionally, mass spectrometry studies revealed that the N-termini of both constructs are sensitive to degradation and that the sites of specific autoproteolysis vary. 展开更多
关键词 HIV-1 PROTEASE Autoproteolysis Self-Proteolytic Activity SITE-DIRECTED Spin-Labeling electron paramagnetic resonance (EPR) Spectroscopy
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Electron Paramagnetic Resonance of Gd3+ in Cs 2Na Y0.75 H o0.25CI6
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作者 Josefina Maldonado Jorge Barreto Jose Luis Boldu Hector del Castillo Eduardo Mufioz Picone 《材料科学与工程(中英文B版)》 2011年第3期352-357,共6页
关键词 电子顺磁共振 温度依赖性 CS 温度范围 解析表达式 对称性 哈密顿
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Elucidating solvent effects on the stability of phenoxyl radicals in monohydric alcohols via electron paramagnetic resonance
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作者 Xinyu Wang Wenjing Sun +1 位作者 Yongtao Wang Haoran Li 《Green Chemical Engineering》 EI CSCD 2024年第4期483-488,共6页
Research on solvent effects is an important and long-standing topic,but there still is some room,especially for the special solvent effect of fluoroalcohols.In this work,we investigated the stability of phenoxyl radic... Research on solvent effects is an important and long-standing topic,but there still is some room,especially for the special solvent effect of fluoroalcohols.In this work,we investigated the stability of phenoxyl radical in monohydric alcohol solvents through in-situ electron paramagnetic resonance detections.The decay behavior of phenoxyl radical showed a reasonable relationship with the mesoscopic structure of alcohols,characterized by smalland wide-angle X-ray scattering.Moreover,the distinct solvent effects of fluoroalcohols were emphasized,and the significant influence of van der Waals distance in the solvents was suggested.Overall,the stability of phenoxyl radical in alcohols was quantified and correlated with the solvent structures.We believe that the established method for stability study on radicals will encourage solvent effect studies on various organic reactions,and the proposed solvent effects in fluoroalcohols may inspire the development of green solvents in both industrial conversions and organic synthesis. 展开更多
关键词 Solvent effect FLUOROALCOHOL Phenoxyl radical STABILITY electron paramagnetic resonance
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Advancements and Prospects in Continuous Wave Time-resolved Electron Paramagnetic Resonance
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作者 ZHANG Shixue ZHOU Shengqi +1 位作者 WU Hao GUO Xingwei 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2024年第5期798-805,共8页
This brief review highlights the techniques and diverse applications of time-resolved electron paramagnetic resonance(TREPR)spectroscopy,underscoring its essential role in elucidating the structures,spin dynamics,and ... This brief review highlights the techniques and diverse applications of time-resolved electron paramagnetic resonance(TREPR)spectroscopy,underscoring its essential role in elucidating the structures,spin dynamics,and reactivities of open-shell systems.Furthermore,we discuss the limitations of traditional TREPR methodologies,particularly their challenges in directly observing reactive radical intermediates under real-world reaction conditions.Lastly,we present the latest advancements in TREPR technology developed in our laboratory,specifically ultrawide single-sideband phase-sensitive detection(U-PSD)TREPR,highlighting its significant impact and tremendous potential in advancing free radical chemistry research.We envision promising future applications of TREPR and its pivotal role in enhancing our understanding of mechanisms involved in complex radical processes and photocatalysis. 展开更多
关键词 Time-resolved electron paramagnetic resonance(TREPR) Ultrawide single-sideband phase-sensitive detection(U-PSD) Spin chemistry Radical chemistry PHOTOCHEMISTRY
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In Situ Electron Paramagnetic Resonance Reveals Fading Mechanism of Mn-Based Prussian Blue Analogue:Accelerated Mn Dissolution Due to Charge Delocalization
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作者 Xiaobing Lou Zonglin Li +4 位作者 Shinuo Kang Yufan Li Sen Ma Fushan Geng Bingwen Hu 《Renewables》 2024年第5期341-352,共12页
Contrasting with Fe-based Prussian blue analogues(PBAs),Mn-based PBAs with higher energy density are more promising cathode materials for Na-ion batteries.However,fast capacity fading has severely impeded its practica... Contrasting with Fe-based Prussian blue analogues(PBAs),Mn-based PBAs with higher energy density are more promising cathode materials for Na-ion batteries.However,fast capacity fading has severely impeded its practical use,which is still not well understood.To elucidate the fading mechanism,in situ and ex situ electron paramagnetic resonance are employed here.The results first demonstrate the charge delocalization of Mn2+and Mn dissolution during cycles,which are further proved to be highly related.Our work reveals the inherent shortcoming of Mn-based PBA cathodes in liquid electrolyte. 展开更多
关键词 electron paramagnetic resonance fading mechanism Prussian blue analogues sodium-ion batteries Mn dissolution
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Analysis of the electron transfer pathway in small laccase by EPR and UV-vis spectroscopy coupled with redox titration
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作者 Lu Yu Aokun Liu +3 位作者 Jian Kuang Ruotong Wei Zhiwen Wang Changlin Tian 《Magnetic Resonance Letters》 2024年第3期52-59,共8页
Bacterial small laccases(SLAC) are promising industrial biocatalysts due to their ability to oxidize a broad range of substrates with exceptional thermostability and tolerance for alkaline p H. Electron transfer betwe... Bacterial small laccases(SLAC) are promising industrial biocatalysts due to their ability to oxidize a broad range of substrates with exceptional thermostability and tolerance for alkaline p H. Electron transfer between substrate, copper centers, and O2is one of the key steps in the catalytic turnover of SLAC. However, limited research has been conducted on the electron transfer pathway of SLAC and SLAC-catalyzed reactions, hindering further engineering of SLAC to produce tunable biocatalysts for novel applications. Herein, the combinational use of electron paramagnetic resonance(EPR) and ultraviolet-visible(UV-vis) spectroscopic methods coupled with redox titration were employed to monitor the electron transfer processes and obtain further insights into the electron transfer pathway in SLAC. The reduction potentials for type 1 copper(T1Cu), type 2 copper(T2Cu) and type 3copper(T3Cu) were determined to be 367 ± 2 mV, 378 ± 5 m V and 403 ± 2 mV,respectively. Moreover, the reduction potential of a selected substrate of SLAC, hydroquinone(HQ), was determined to be 288 mV using cyclic voltammetry(CV). In this way, an electron transfer pathway was identified based on the reduction potentials. Specifically,electrons are transferred from HQ to T1Cu, then to T2Cu and T3Cu, and finally to O2.Furthermore, superhyperfine splitting observed via EPR during redox titration indicated a modification in the covalency of T2Cu upon electron uptake, suggesting a conformational alteration in the protein environment surrounding the copper sites, which could potentially influence the reduction potential of the copper sites during catalytic processes. The results presented here not only provide a comprehensive method for analyzing the electron transfer pathway in metalloenzymes through reduction potential measurements, but also offer valuable insights for further engineering and directed evolution studies of SLAC in the aim for biotechnological and industrial applications. 展开更多
关键词 electron paramagnetic resonance Redox titration electron transfer Reduction Potential Small laccase
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Developing in situ electron paramagnetic resonance characterization for understanding electron transfer of rechargeable batteries 被引量:1
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作者 Bin Wang Wanli Wang +5 位作者 Kang Sun Yujie Xu Yi Sun Qiang Li Han Hu Mingbo Wu 《Nano Research》 SCIE EI CSCD 2023年第10期11992-12012,共21页
Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable sources.To facilitate the development of these devices,it is important to ... Electrochemical energy storage devices are pivotal in achieving“carbon neutrality”by enabling the storage of energy generated from renewable sources.To facilitate the development of these devices,it is important to gain insight into the underlying the single-/multi-electron transfer process.This can be achieved through in-time detection under operational conditions,but there are limited tools available for monitoring electron transfer under operando conditions.Electron paramagnetic resonance(EPR)is a powerful technique that can meet these expectations,as it is highly sensitive to unpaired electrons and can detect changes of paramagnetic centres.Despite the long history of in situ electrochemical EPR research,its potential has been surprisingly underutilized due to the need for strict operando cell design under special testing conditions.This review comprehensively summarizes recent efforts to understand energy storage mechanisms using in situ/operando EPR,with the aim of drawing researchers’attention to this powerful technique.After introducing the fundamental principles of EPR,we describe the critical advances made in detecting batteries using operando EPR,along with the remaining challenges and opportunities for future development of this technology in batteries.We emphasize the need for strict operando cell design and the importance of designing experiments that closely mimic real-world conditions.We believe that this review will provide innovative solutions to solve tough problems that researchers may encounter during their battery research,and ultimately contribute to the development of more efficient and sustainable energy storage devices. 展开更多
关键词 electron paramagnetic resonance in situ energy storage BATTERY
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Thermal evolution of source rocks in sedimentary basin by using electron paramagnetic resonance technique 被引量:3
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作者 邱楠生 汪集旸 +3 位作者 周礼成 张启明 陈贵云 蔡世祥 《Chinese Science Bulletin》 SCIE EI CAS 1995年第19期1625-1628,共4页
1 Methods and principles Based on the variation of free radicals, thermal evolution of organic matter in source rocks in sedimentary basin can be identified by using electron paramagnetic resonance (EPR) technique. Th... 1 Methods and principles Based on the variation of free radicals, thermal evolution of organic matter in source rocks in sedimentary basin can be identified by using electron paramagnetic resonance (EPR) technique. This is based on the changes of free radicals with the evolution of kerogen, which may lead to the changes of EPR spectra. The number of free radicals 展开更多
关键词 electron paramagnetic resonance (EPR) free RADICAL paleoheat flow MATURITY of organic matter.
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Electron paramagnetic resonance in monitoring of nitric oxide production after kidney transplantation in rats 被引量:4
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作者 徐涛 陈希 +6 位作者 王晓峰 黄晓波 曲星珂 叶海云 张小东 侯树坤 朱积川 《Chinese Medical Journal》 SCIE CAS CSCD 2004年第10期1552-1557,共6页
Background Much research has been focused on ischemia/reperfusion injury (IRI) to the transplanted organs. As a free radical, nitric oxide (NO) plays an important role in IRI. In this study, the production of NO and ... Background Much research has been focused on ischemia/reperfusion injury (IRI) to the transplanted organs. As a free radical, nitric oxide (NO) plays an important role in IRI. In this study, the production of NO and its functions during IRI were monitored in rat models after allotransplantation of kidney grafts.Methods Of 75 male LEW rats, 30 served as donors, and the remaining 45 rats were divided into three groups (15 rats in each group): controls (group 1), kidney allotransplantation followed by bilateral nephrectomy during reperfusion (group 2), 2 hours before operation, donors and recipients were treated with NG-nitro L-arginine methyl ester (L-NAME), a NO synthase inhibitor, at a dose of 30 mg/kg (group 3). Bilateral nephrectomies were performed while kidney grafts were reperfused. The kidney grafts were hypothemically stored for 24 hours. The production of NO before and after reperfusion was measured by electron paramagnetic resonance (EPR). The creatinine level, the glomerular filtration rate (GFR) and the protein carbonyl content in tissue samples were recorded on the first and the fifth day after operation. The data were evaluated by one-way analysis of variance. Differences were considered to be statistically significant when a P value was less than 0.05.Results After reperfusion for 15 minutes, the production of NO increased remarkably and kept increasing till 120 minutes, after which the level returned to normal. In group 3, which was pretreated with L-NAME, creatinine levels were higher than those in group 2 at the 24th hour (4.10±0.50 mg/dl vs. 3.77±0.42 mg/dl, P<0.05) and the 120th hour (3.19±0.79 mg/dl vs. 2.22±0.53 mg/dl, P<0.05). GFR levels in group 3 were lower than those in group 2 at the 24th hour (0.50±0.12 ml/min vs. 0.71±0.19 ml/min, P<0.05) and the 120th hour (0.59±0.38 ml/min vs. 1.27±0.23 ml/min, P<0.01). The content of protein carbonyl in tissue samples of group 3 was lower than that in group 2 at the 24th hour (29.01±7.02 nmol/mg protein vs. 49.39±13.13 nmol/mg protein, P<0.05), but was higher than that at the 120th hour (75.71±16.74 nmol/mg protein vs. 57.93±15.32 nmol/mg protein, P<0.05).Conclusions After transplantation of hypothemically stored kidney grafts, the increased NO production in the early stage has protective effects on the transplanted kidney. Application of L-NAME to inhibit NO production is harmful to the recovery of the renal functions of kidney grafts. 展开更多
关键词 nitric oxide · kidney transplantation · ischemia/reperfusion injury · electron paramagnetic resonance
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Spin probes for electron paramagnetic resonance imaging 被引量:7
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作者 YAN GuoPing PENG Lei +2 位作者 JIAN ShuangQuan LI Liang BOTTLE Steven Eric 《Chinese Science Bulletin》 SCIE EI CAS 2008年第24期3777-3789,共13页
Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of st... Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of stable spin probes, low frequency EPR imaging has recently allowed the use of large tissue samples or whole animals in vivo in the field of biology and medicine. It is normally necessary to introduce prior intravenous or intramuscular infusion of stable or slowly metabolizable non-toxic water-soluble paramagnetic materials, or stable implantable particulate materials as spin probes into the system. The classification and research progress of spin probes at present were described briefly. Three important potential approaches in water-soluble paramagnetic materials design including deuterated, site-specific and macromolecular conjugated nitroxides were also investigated. 展开更多
关键词 顺磁共振成像 旋转探头 氘化 大分子化合物
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