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Impact of time between meniscal injury and isolated meniscus repair on post-operative outcomes:A systematic review
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作者 Kashif Javid Xavier Akins +2 位作者 Nicole G Lemaster Amer Ahmad Austin V Stone 《World Journal of Clinical Cases》 SCIE 2025年第7期39-45,共7页
BACKGROUND Meniscal tears are one of the most common knee injuries.After the diagnosis of a meniscal tear has been made,there are several factors physicians use to guide clinical decision-making.The influence of time ... BACKGROUND Meniscal tears are one of the most common knee injuries.After the diagnosis of a meniscal tear has been made,there are several factors physicians use to guide clinical decision-making.The influence of time between injury and isolated meniscus repair on patient outcomes is not well described.Assessing this relationship is important as it may influence clinical decision-making and can add to the preoperative patient education process.We hypothesized that increasing the time from injury to meniscus surgery would worsen postoperative outcomes.AIM To investigate the current literature for data on the relationship between time between meniscus injury and repair on patient outcomes.METHODS PubMed,Academic Search Complete,MEDLINE,CINAHL,and SPORTDiscus were searched for studies published between January 1,1995 and July 13,2023 on isolated meniscus repair.Exclusion criteria included concomitant ligament surgery,incomplete outcomes or time to surgery data,and meniscectomies.Patient demographics,time to injury,and postoperative outcomes from each study were abstracted and analyzed.RESULTS Five studies met all inclusion and exclusion criteria.There were 204(121 male,83 female)patients included.Three of five(60%)studies determined that time between injury and surgery was not statistically significant for postoperative Lysholm scores(P=0.62),Tegner scores(P=0.46),failure rate(P=0.45,P=0.86),and International Knee Documentation Committee scores(P=0.65).Two of five(40%)studies found a statistically significant increase in Lysholm scores with shorter time to surgery(P=0.03)and a statistically significant association between progression of medial meniscus extrusion ratio(P=0.01)and increasing time to surgery.CONCLUSION Our results do not support the hypothesis that increased time from injury to isolated meniscus surgery worsens postoperative outcomes.Decision-making primarily based on injury interval is thus not recommended. 展开更多
关键词 MENISCUS Meniscal Meniscus repair MENISCECTOMY Patient reported outcomes Postoperative outcomes time to surgery Injury interval
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Storage time affects the level and diagnostic efficacy of plasma biomarkers for neurodegenerative diseases
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作者 Lifang Zhao Mingkai Zhang +4 位作者 Qimeng Li Xuemin Wang Jie Lu Ying Han Yanning Cai 《Neural Regeneration Research》 SCIE CAS 2025年第8期2373-2381,共9页
Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is k... Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is known about the long-term stability of these biomarker proteins in plasma samples stored at-80°C.We aimed to explore how storage time would affect the diagnostic accuracy of these biomarkers using a large cohort.Plasma samples from 229 cognitively unimpaired individuals,encompassing healthy controls and those experiencing subjective cognitive decline,as well as 99 patients with cognitive impairment,comprising those with mild cognitive impairment and dementia,were acquired from the Sino Longitudinal Study on Cognitive Decline project.These samples were stored at-80°C for up to 6 years before being used in this study.Our results showed that plasma levels of Aβ42,Aβ40,neurofilament light chain,and glial fibrillary acidic protein were not significantly correlated with sample storage time.However,the level of total tau showed a negative correlation with sample storage time.Notably,in individuals without cognitive impairment,plasma levels of total protein and tau phosphorylated protein threonine 181(p-tau181)also showed a negative correlation with sample storage time.This was not observed in individuals with cognitive impairment.Consequently,we speculate that the diagnostic accuracy of plasma p-tau181 and the p-tau181 to total tau ratio may be influenced by sample storage time.Therefore,caution is advised when using these plasma biomarkers for the identification of neurodegenerative diseases,such as Alzheimer's disease.Furthermore,in cohort studies,it is important to consider the impact of storage time on the overall results. 展开更多
关键词 Alzheimer’s disease amyloid-β diagnostic ability glial fibrillary acidic protein NEURODEGENERATION neurofilament light chain plasma biomarkers single molecule array storage time tau
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RELAXATION TIME LIMITS PROBLEM FOR HYDRODYNAMIC MODELS IN SEMICONDUCTOR SCIENCE 被引量:3
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作者 黎勇 《Acta Mathematica Scientia》 SCIE CSCD 2007年第2期437-448,共12页
In this article, two relaxation time limits, namely, the momentum relaxation time limit and the energy relaxation time limit are considered. By the compactness argument, it is obtained that the smooth solutions of the... In this article, two relaxation time limits, namely, the momentum relaxation time limit and the energy relaxation time limit are considered. By the compactness argument, it is obtained that the smooth solutions of the multidimensional nonisentropic Euler-Poisson problem converge to the solutions of an energy transport model or a drift diffusion model, respectively, with respect to different time scales. 展开更多
关键词 Hydrodynamic models nonisentropic Euler-Poisson momentum relaxation time limit energy relaxation time limit
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A time domain induced polarization relaxation time spectrum inversion method based on a damping factor and residual correction 被引量:2
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作者 Liu Xiaonan Kong Li +1 位作者 Zhou Kaibo Zhang Pu 《Petroleum Science》 SCIE CAS CSCD 2014年第4期519-525,共7页
Relaxation time spectra (RTS) derived from time domain induced polarization data (TDIP) are helpful to assess oil reservoir pore structures. However, due to the sensitivity to the signal-to-noise ratio (SNR), th... Relaxation time spectra (RTS) derived from time domain induced polarization data (TDIP) are helpful to assess oil reservoir pore structures. However, due to the sensitivity to the signal-to-noise ratio (SNR), the inversion accuracy of the traditional singular value decomposition (SVD) inversion method reduces with a decrease of SNR. In order to enhance the inversion accuracy and improve robustness of the inversion method to the SNR, an improved inversion method, based on damping factor and spectrum component residual correction, is proposed in this study. The numerical inversion results show that the oscillation of the RTS derived from the SVD method increased with a decrease of SNR, which makes it impossible to get accurate inversion components. However, the SNR has little influence on inversion components of the improved method, and the RTS has high inversion accuracy and robustness. Moreover, RTS derived from core sample data is basically in accord with the pore-size distribution curve, and the RTS derived from the actual induced polarization logging data is smooth and continuous, which indicates that the improved method is practicable. 展开更多
关键词 Inversion method damping factor relaxation time spectrum time domain inducedpolarization spectrum component residual correction
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Multi-relaxation time lattice Boltzmann simulation of inertial secondary flow in a curved microchannel 被引量:2
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作者 孙东科 项楠 +3 位作者 姜迪 陈科 易红 倪中华 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第11期376-384,共9页
The inertial secondary flow is particularly important tbr hydrodynamic lbcusing and particle manipulation m biomed- ical research. In this paper, the development of the inertial secondary flow structure in a curved mi... The inertial secondary flow is particularly important tbr hydrodynamic lbcusing and particle manipulation m biomed- ical research. In this paper, the development of the inertial secondary flow structure in a curved microchannel was investi- gated by the multi relaxation time lattice Boltzmann equation model with a force term. The numerical results indicate that the viscous and inertial competition dominates the development of secondary flow structure development. The Reynolds number, Dean number, and the cross section aspect ratio influence significantly on the development of the secondary vor- texes. Both the intensity of secondary flow and the distance between the normalized vortex centers are functions of Dean numbers but independent of channel curvature radius. In addition, the competition mechanism between the viscous and inertial effects were discussed by performing the particle focusing experiments. The present investigation provides an improved understanding of the development of inertial secondary flows in curved microchannels. 展开更多
关键词 lattice Boltzmann method multi relaxation time MICROCHANNEL inertial secondary flow
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Prediction of impedance responses of protonic ceramic cells using artificial neural network tuned with the distribution of relaxation times 被引量:2
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作者 Xuhao Liu Zilin Yan +6 位作者 Junwei Wu Jake Huang Yifeng Zheng Neal PSullivan Ryan O'Hayre Zheng Zhong Zehua Pan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第3期582-588,I0016,共8页
A deep-learning-based framework is proposed to predict the impedance response and underlying electrochemical behavior of the reversible protonic ceramic cell(PCC) across a wide variety of different operating condition... A deep-learning-based framework is proposed to predict the impedance response and underlying electrochemical behavior of the reversible protonic ceramic cell(PCC) across a wide variety of different operating conditions.Electrochemical impedance spectra(EIS) of PCCs were first acquired under a variety of opera ting conditions to provide a dataset containing 36 sets of EIS spectra for the model.An artificial neural network(ANN) was then trained to model the relationship between the cell operating condition and EIS response.Finally,ANN model-predicted EIS spectra were analyzed by the distribution of relaxation times(DRT) and compared to DRT spectra obtained from the experimental EIS data,enabling an assessment of the accumulative errors from the predicted EIS data vs the predicted DRT.We show that in certain cases,although the R^(2)of the predicted EIS curve may be> 0.98,the R^(2)of the predicted DRT may be as low as~0.3.This can lead to an inaccurate ANN prediction of the underlying time-resolved electrochemical response,although the apparent accuracy as evaluated from the EIS prediction may seem acceptable.After adjustment of the parameters of the ANN framework,the average R^(2)of the DRTs derived from the predicted EIS can be improved to 0.9667.Thus,we demonstrate that a properly tuned ANN model can be used as an effective tool to predict not only the EIS,but also the DRT of complex electrochemical systems. 展开更多
关键词 Protonic ceramic fuel cell/electrolysis cell Electrochemical impedance spectroscopy Distribution of relaxation times Artificial neural network
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Effective relaxation time and viscosity of the earth inferred from the postseismic vertical deformations of the 1990 MS=7.0 Gonghe earthquake 被引量:1
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作者 王庆良 巩守文 +1 位作者 张希 祝意青 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第5期40-47,共8页
The postseismic vertical deformation rates of the 1990 Gonghe M S=7.0 earthquake appears to have decreased exponentially. Based on Okada′s coseismic surface displacement solution caused by a uniform fault slip... The postseismic vertical deformation rates of the 1990 Gonghe M S=7.0 earthquake appears to have decreased exponentially. Based on Okada′s coseismic surface displacement solution caused by a uniform fault slip in an elastic homogeneous half space, we derived its postseismic surface displacement by using a single layer standard linear solid model, and further derived a simplified formula for determining the effective relaxation time and viscosity of the earth, which is independent of the dislocation parameters of the causative fault. From the postseismic vertical deformation of the 1990 Gonghe earthquake, we inferred that the effective relaxation time defined by τ = η/μ is 2.6 years, and the effective viscosity η is about 10 18 Pa·s. 展开更多
关键词 Gonghe earthquake POSTSEISMIC vertical deformation earth medium relaxation time VISCOSITY
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Effect of optical pumping on the momentum relaxation time of graphene in the terahertz range 被引量:1
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作者 左志高 王平 +2 位作者 凌福日 刘劲松 姚建铨 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第9期579-582,共4页
The momentum relaxation time of a photoexcited graphene in the THz frequency range has been studied by using terabertz time domain spectroscopy under optical pumping at room temperature. It is found that the momentum ... The momentum relaxation time of a photoexcited graphene in the THz frequency range has been studied by using terabertz time domain spectroscopy under optical pumping at room temperature. It is found that the momentum relaxation time of the graphene as a function of the optical pumping intensity exhibits a threshold behavior. The features of the momentum relaxation time as a function of the optical pumping intensity are also investigated. The results are useful for understanding the basic underlying physics of graphene scattering as well as finding the possible applications in carbon- based electronics. 展开更多
关键词 GRAPHENE momentum relaxation time optical pumping TERAHERTZ
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Combined immersed boundary method and multiple-relaxation-time lattice Boltzmann flux solver for numerical simulations of incompressible flows 被引量:1
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作者 Xiaodi WU Fu CHEN Huaping LIU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2017年第12期1679-1696,共18页
A method combining the immersed boundary technique and a multi- relaxation-time (MRT) lattice Boltzmann flux solver (LBFS) is presented for numerical simulation of incompressible flows over circular and elliptic c... A method combining the immersed boundary technique and a multi- relaxation-time (MRT) lattice Boltzmann flux solver (LBFS) is presented for numerical simulation of incompressible flows over circular and elliptic cylinders and NACA 0012 Airfoil. The method uses a simple Cartesian mesh to simulate flows past immersed complicated bodies. With the Chapman-Enskog expansion analysis, a transform is performed between the Navier-Stokes and lattice Boltzmann equations (LBEs). The LBFS is used to discretize the macroscopic differential equations with a finite volume method and evaluate the interface fluxes through local reconstruction of the lattice Boltzmann solution. The immersed boundary technique is used to correct the intermediate velocity around the solid boundary to satisfy the no-slip boundary condition. Agreement of simulation results with the data found in the literature shows reliability of the proposed method in simulating laminar flows on a Cartesian mesh. 展开更多
关键词 immersed boundary method lattice Boltzmann equation (LBE) multiple relaxation time incompressible flow
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Effect of relaxation time on the squeezed correlations of bosons for evolving sources in relativistic heavy-ion collisions 被引量:1
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作者 Wei-Ning Zhang Peng-Zhi Xu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第2期87-92,共6页
The squeezed back-to-back correlation(SBBC)of a boson-antiboson pair is sensitive to the time distribution of the particle-emitting source,and the SBBC function for an evolving source is expected to be affected by the... The squeezed back-to-back correlation(SBBC)of a boson-antiboson pair is sensitive to the time distribution of the particle-emitting source,and the SBBC function for an evolving source is expected to be affected by the relaxation time of the system.In this study,we investigated the effect of relaxation time on the SBBC function.We propose a method for calculating the SBBC function with relaxation-time approximation for evolving sources.SBBC functions of D^(0)D^(-0)in relativistic heavy-ion collisions were investigated using a hydrodynamic model.We found that the relaxation time reduces the amplitudes of the SBBC functions.This becomes apparent for long relaxation times and large initial relative deviations of the chaotic and squeezed amplitudes from their equilibrium values in the temporal steps. 展开更多
关键词 relaxation time Squeezed back-to-back correlation Evolving source Relativistic heavy-ion collisions
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4种植物源性成分多重real-time PCR检测方法的建立及其在食用淀粉中的应用 被引量:3
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作者 范维 高晓月 +4 位作者 董雨馨 刘虹宇 李贺楠 赵文涛 郭文萍 《食品科学》 EI CAS CSCD 北大核心 2024年第1期210-216,共7页
建立一种可同时快速检测红薯、木薯、马铃薯、玉米源性成分的多重实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)方法。分别以红薯g3pdh基因、木薯g3pdh基因、马铃薯UGPase基因、玉米zSSIIb基因为靶基因设计... 建立一种可同时快速检测红薯、木薯、马铃薯、玉米源性成分的多重实时聚合酶链式反应(real-time polymerase chain reaction,real-time PCR)方法。分别以红薯g3pdh基因、木薯g3pdh基因、马铃薯UGPase基因、玉米zSSIIb基因为靶基因设计特异性引物和TaqMan探针,以18S rRNA基因为内参基因,建立多重real-time PCR方法,开展方法学验证,并对不同掺入比例模拟样品和实际淀粉样品进行检测。结果显示,该方法具有高通量、特异性强、灵敏度高等优点。与15种非目标源性均无交叉反应;对目标DNA的检测灵敏度可达到3×10^(-3) ng/μL,且具有良好的线性关系和扩增效率;对淀粉样品的检出限可达0.1%,对50份实际样品进行检测,结果与参比方法一致,说明建立的多重real-time PCR法可用于食用淀粉种类掺假鉴别检测。 展开更多
关键词 多重实时聚合酶链式反应 食用淀粉 木薯 红薯 马铃薯 玉米
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Concise review of relaxations and approximation algorithms for nonidentical parallel-machine scheduling to minimize total weighted completion times 被引量:1
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作者 Li Kai Yang Shanlin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第4期827-834,共8页
A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time. Models and relaxations are collected. Most of these problems are NP-hard... A class of nonidentical parallel machine scheduling problems are considered in which the goal is to minimize the total weighted completion time. Models and relaxations are collected. Most of these problems are NP-hard, in the strong sense, or open problems, therefore approximation algorithms are studied. The review reveals that there exist some potential areas worthy of further research. 展开更多
关键词 parallel machine SCHEDULING REVIEW total weighted completion time relaxation algorithm
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Time-Dependent Stokes Shift from Solvent Dielectric Relaxation
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作者 许婧 王全德 +3 位作者 朱权 傅克祥 何福城 李象远 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第3期297-302,I0001,共7页
The Stokes shift response function, which is related to the time dependent solvation energy, is calculated with the dielectric response function and a novel expression of nonequilibrium solvation energy. In the deriva... The Stokes shift response function, which is related to the time dependent solvation energy, is calculated with the dielectric response function and a novel expression of nonequilibrium solvation energy. In the derivation, relationship between the polarization and the dielectric response function is used. With the dipole-in-a-sphere model applied to the system coumarin 343 and water as the solvent, encouraging agreement with the experimental data from Jimenez et al. is obtained [Nature 369, 471 (1994)]. 展开更多
关键词 Stokes shift Solvation energy Characteristic time
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Measurement scheme to detect α relaxation time of glass-forming liquid 被引量:1
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作者 Xing-Yu Zhao Li-Na Wang +2 位作者 Hong-Mei Yin Heng-Wei Zhou Yi-Neng Huang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第8期276-281,共6页
A measurement scheme for detecting theαrelaxation time(τ)of glass-forming liquid is proposed,which is based on the measured ionic conductivity of the liquid doped with probing ions by low-and middle-frequency dielec... A measurement scheme for detecting theαrelaxation time(τ)of glass-forming liquid is proposed,which is based on the measured ionic conductivity of the liquid doped with probing ions by low-and middle-frequency dielectric spectroscopy and according to the Nernst-Einstein,Stokes-Einstein,and Maxwell equations.The obtainedτvalues of glycerol and propylene carbonate by the scheme are consistent with those obtained by traditional dielectric spectroscopy,which confirms its reliability and accuracy.Moreover,theτof 1,2-propanediol in a larger temperature range is compared with existing data. 展开更多
关键词 αrelaxation IONIC CONDUCTIVITY GLASS-FORMING liquid DIELECTRIC spectroscopy
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Investigation on Exciton Relaxation Kinetics of ZnCulnS/ZnSe/ZnS Quantum Dots by Time-Resolved Spectroscopy Techniques
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作者 李雪璁 隋宁 张宇 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第1期54-58,I0001,共6页
The exciton relaxation kinetics of ZnCuInS/ZnSe/ZnS quantum dots (QDs) is investigated by time-resolved spectroscopy techniques in detail. Based on the rate distribution model, the wavelength-dependent emission dyna... The exciton relaxation kinetics of ZnCuInS/ZnSe/ZnS quantum dots (QDs) is investigated by time-resolved spectroscopy techniques in detail. Based on the rate distribution model, the wavelength-dependent emission dynamics shows that the intrinsic exciton, the exciton in the interface defect state and that in donor-acceptor pair state (DAPS) together participate in the photoluminescence process of QDs, and the whole emission process is mainly dependent on the DAPS emission. Transient absorption data show that the intrinsic exciton and the interface defect species maybe together appear after excitation and the intensity-dependent Auger recombination process also exists in QDs at high excitation intensity. 展开更多
关键词 Quantum dots time-resolved spectroscopy Exciton relaxation kinetics
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The Influence of Organo-Clay Ratio in the HIPS-OMMT Nanocomposites Analyzed by Proton Spin-Lattice and Spin-Spin Relaxation Times 被引量:1
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作者 Paulo Sérgio Rangel Cruz da Silva Lívia Rodrigues Menezes Maria Inês Bruno Tavares 《Materials Sciences and Applications》 2016年第3期150-158,共9页
Spin-lattice and spin-spin relaxation times are one of the most attractive tools in the solid-state nuclear magnetic resonance spectroscopy to evaluate the level of clay dispersion in the nanocomposite matrices. The e... Spin-lattice and spin-spin relaxation times are one of the most attractive tools in the solid-state nuclear magnetic resonance spectroscopy to evaluate the level of clay dispersion in the nanocomposite matrices. The efficiency of the relaxation processes can be used to evaluate the nanoparticles intermolecular interactions and, consequently, the dispersion of them in the polymer matrix, the molecular dynamic of the hybrid compounds, as well as the molecular domains formation in an organic material. The determination of relaxation parameters was carried out to evaluate the organoclay exfoliation and intercalation process in the polymeric matrix, in addition to their dispersion and distribution in the matrix. The proton NMR relaxation data showed that the polymeric nanomaterials investigated presented good intermolecular interaction that promoted good nanoparticles dispersion and distribution in the hybrid materials. The proportion of 2% clay promoted a greater heterogeneity in the matrix compared to other ratios;1% clay influenced only to the higher molecular rigidity phase;and 3% clay had a decrease in heterogeneity compared to 2% though still influenced the matrix as a whole. These results prove the efficiency of NMR technique in the evaluation of nanofillers interaction with polymer matrices, as well as their dispersion and distribution. 展开更多
关键词 Polymeric Nanocomposites Nanoparticles relaxation times NMR
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Long-Time Magnetic Relaxation in Antiferromagnetic Topological Material EuCd_(2)As_(2) 被引量:1
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作者 Yang Wang Cong Li +12 位作者 Yong Li Xuebo Zhou Wei Wu Runze Yu Jianfa Zhao Chaohui Yin Youguo Shi Changqing Jin Jianlin Luo Lin Zhao Tao Xiang Guodong Liu X.J.Zhou 《Chinese Physics Letters》 SCIE CAS CSCD 2021年第7期96-105,共10页
Magnetic topological materials have attracted much attention due to the correlation between topology and magnetism.Recent studies suggest that EuCd_(2)As_(2) is an antiferromagnetic topological material.Here by carryi... Magnetic topological materials have attracted much attention due to the correlation between topology and magnetism.Recent studies suggest that EuCd_(2)As_(2) is an antiferromagnetic topological material.Here by carrying out thorough magnetic,electrical and thermodynamic property measurements,we discover a long-time relaxation of the magnetic susceptibility in EuCd_(2)As_(2).The(001)in-plane magnetic susceptibility at 5 K is found to continuously increase up to∼10%over the time of∼14 hours.The magnetic relaxation is anisotropic and strongly depends on the temperature and the applied magnetic field.These results will stimulate further theoretical and experimental studies to understand the origin of the relaxation process and its effect on the electronic structure and physical properties of the magnetic topological materials. 展开更多
关键词 relaxation SUSCEPTIBILITY MAGNETIC
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Approach to Phonon Relaxation Time and Mean Free Path in Nonlinear Lattices 被引量:1
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作者 Yue Liu Dahai He 《Chinese Physics Letters》 SCIE CAS CSCD 2021年第4期56-60,共5页
Based on the self-consistent phonon theory,the spectral energy density is calculated by the canonical transformation and the Fourier transformation.Through fitting the spectral energy density by the Lorentzian profile... Based on the self-consistent phonon theory,the spectral energy density is calculated by the canonical transformation and the Fourier transformation.Through fitting the spectral energy density by the Lorentzian profile,the phonon frequency as well as the phonon relaxation time is obtained in one-dimensional nonlinear lattices,which is validated in the Fermi-Pasta-Ulam-β(FPU-β) and φ^(4) lattices at different temperatures.The phonon mean free path is then evaluated in terms of the phonon relaxation time and phonon group velocity.The results show that,in the FPU-β lattice,the phonon mean free path as well as the phonon relaxation time displays divergent power-law behavior.The divergent exponent coincides well with that derived from the Peierls-Boltzmann theory at weak anharmonic nonlinearity.The value of the divergent exponent expects a power-law divergent heat conductivity with system size,which violates Fourier’s law.For the φ^(4) lattice,both the phonon relaxation time and mean free path are finite,which ensures normal heat conduction. 展开更多
关键词 PHONON relaxation EXPONENT
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DEFORMATION DUE TO TIME HARMONIC SOURCES IN MICROPOLAR THERMOELASTIC MEDIUM POSSESSING CUBIC SYMMETRY WITH TWO RELAXATION TIMES 被引量:1
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作者 Rajneesh Kumar Praveen Ailawalia 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第6期781-792,共12页
The response of a micropolar thermoelastic medium possessing cubic symmetry with two relaxation times due to time harmonic sources is investigated. Fourier transform is employed and the transform is inverted by using ... The response of a micropolar thermoelastic medium possessing cubic symmetry with two relaxation times due to time harmonic sources is investigated. Fourier transform is employed and the transform is inverted by using a numerical inversion technique. The components of displacement, stress, microrotation and temperature distribution in the physical domain are obtained numerically. The results of normal displacement, normal force stress, tangential couple stress and temperature distribution are compared for micropolar cubic crystal and micropolar isotropic solid. The numerical results are illustrated graphically for a particular material. Some special cases are also deduced. 展开更多
关键词 time harmonic THERMOELASTIC micropolar medium cubic symmetry MICROROTATION Fourier transform
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MECHANICAL RELAXATION TIME OF A TWO-COMPONENT EPOXY NETWORKLiClO_4 POLYMER ELECTROLYTE
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作者 彭新生 吴淑云 陈东霖 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1993年第2期133-143,共11页
The mechanical relaxation time of a two-component epoxy network-LiClO_4 system as a polymer electrolyte was investigated. The network is composed of diglycidyl ether of polyethylene glycol (DGEPEG) and triglycidyl eth... The mechanical relaxation time of a two-component epoxy network-LiClO_4 system as a polymer electrolyte was investigated. The network is composed of diglycidyl ether of polyethylene glycol (DGEPEG) and triglycidyl ether of glycerol (TGEG), wherein LiCIO_4 was incorporated and acts as both the ionic carrier and the curing catalyst. As the relaxation time is informative to the segmental mobility, which is known to be essential for ionic conductivity, the average relaxation times of the specimens were determined through master curve construction. Experimental results showed that the salt concentration, molecular weight of PEG in DGEPEG and DGEPEG/TGEG ratio have profound effect on the relaxation time of the specimen. Among these factors , the former reinforces the network chains, leading to lengthen the relaxation time, whereas the latter two are in favour of the chain flexibility and show an opposite effect. The findings was rationalized in terms of the free volume concept. 展开更多
关键词 Polymer solid electrolyte Mechanical relaxation time Segmental mobility Two-component epoxy network-LiClO_4 complex.
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