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Analytical solutions to the precession relaxation of magnetization with uniaxial anisotropy
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作者 张泽南 贾镇林 薛德胜 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期656-660,共5页
Based on the Landau-Lifshitz-Gilbert(LLG)equation,the precession relaxation of magnetization is studied when the external field H is parallel to the uniaxial anisotropic field H_(k).The evolution of three-component ma... Based on the Landau-Lifshitz-Gilbert(LLG)equation,the precession relaxation of magnetization is studied when the external field H is parallel to the uniaxial anisotropic field H_(k).The evolution of three-component magnetization is solved analytically under the condition of H=nH_(k)(n=3,1 and 0).It is found that with an increase of H or a decrease of the initial polar angle of magnetization,the relaxation time decreases and the angular frequency of magnetization increases.For comparison,the analytical solution for H_(k)=0 is also given.When the magnetization becomes stable,the angular frequency is proportional to the total effective field acting on the magnetization.The analytical solutions are not only conducive to the understanding of the precession relaxation of magnetization,but also can be used as a standard model to test the numerical calculation of LLG equation. 展开更多
关键词 precession relaxation Landau-Lifshitz-Gilbert(LLG)equation uniaxial anisotropy analytical solutions
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Solid-state impedance spectroscopy studies of dielectric properties and relaxation processes in Na_(2)O–V_(2)O_(5)–Nb_(2)O_(5)–P_(2)O_(5) glass
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作者 Sara Marijan Luka Pavic 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CSCD 2024年第1期186-196,共11页
Solid-state impedance spectroscopy(SS-IS)was used to investigate the influence of structural modifications resulting from the addition of Nb2O5 on the dielectric properties and relaxation processes in the quaternary m... Solid-state impedance spectroscopy(SS-IS)was used to investigate the influence of structural modifications resulting from the addition of Nb2O5 on the dielectric properties and relaxation processes in the quaternary mixed glass former(MGF)system 35Na_(2)O–10V_(2)O_(5)–(55-x)P_(2)O_(5)–xNb_(2)O_(5)(x=0–40,mol%).The dielectric parameters,including the dielectric strength and dielectric loss,are determined from the frequency and temperature-dependent complex permittivity data,revealing a significant dependence on the Nb2O5 content.The transition from a predominantly phosphate glass network(x<10,region I)to a mixed niobate–phosphate glass net-work(10≤x≤20,region II)leads to an increase in the dielectric parameters,which correlates with the observed trend in the direct-cur-rent(DC)conductivity.In the predominantly niobate network(x≥25,region III),the highly polarizable nature of Nb5+ions leads to a fur-ther increase in the dielectric permittivity and dielectric strength.This is particularly evident in Nb-40 glass-ceramic,which contains Na_(13)Nb_(35)O_(94) crystalline phase with a tungsten bronze structure and exhibits the highest dielectric permittivity of 61.81 and the lowest loss factor of 0.032 at 303 K and 10 kHz.The relaxation studies,analyzed through modulus formalism and complex impedance data,show that DC conductivity and relaxation processes are governed by the same mechanism,attributed to ionic conductivity.In contrast to glasses with a single peak in frequency dependence of imaginary part of electrical modulus,M″(ω),Nb-40 glass-ceramic exhibits two distinct contributions with similar relaxation times.The high-frequency peak indicates bulk ionic conductivity,while the additional low-fre-quency peak is associated with the grain boundary effect,confirmed by the electrical equivalent circuit(EEC)modelling.The scaling characteristics of permittivity and conductivity spectra,along with the electrical modulus,validate time-temperature superposition and demonstrate a strong correlation with composition and modification of the glass structure upon Nb_(2)O_(5) incorporation. 展开更多
关键词 phosphate glasses GLASS-CERAMICS impedance spectroscopy dielectric properties relaxation processes permittivity scaling conductivity scaling modulus formalism
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Effectiveness of aromatherapy with lavender compared to progressive muscle relaxation on anxiety and vital signs in patients under spinal anesthesia:A randomized clinical trial
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作者 Nazanin AMINI Safoora OMIDVAR +2 位作者 Masoomeh Noruzi ZAMENJANI Mehdi HARORANI Hesameddin MODIR 《Journal of Integrative Nursing》 2024年第2期90-95,共6页
Objective:This study aimed to determine the effectiveness of aromatherapy with lavender essential oil compared to progressive muscle relaxation(PMR)on anxiety and vital signs of patients under spinal anesthesia.Materi... Objective:This study aimed to determine the effectiveness of aromatherapy with lavender essential oil compared to progressive muscle relaxation(PMR)on anxiety and vital signs of patients under spinal anesthesia.Materials and Methods:This clinical trial was conducted on 120 spinal anesthesia candidates who were randomly assigned into three groups of 40 including control,PMR(Jacobsen group),and aromatherapy.The state-trait anxiety inventory was completed on surgery day and 15 min after the end of the intervention by the samples of all three groups,and at the same time as completing the questionnaire,vital signs were also measured and recorded.Results:The mean score of anxiety after intervention was lower than that before the intervention in the aromatherapy group(P<0.001).The mean score of anxiety in the aromatherapy group was significantly lower than that in the Jacobsen group(P<0.001).Moreover,data analysis showed a significant decrease in the mean arterial blood pressure scores of the PMR(P=008)and aromatherapy(P<0.001)groups and a statistically significant increase in the mean heart rate scores in the control group(P=0.002).Conclusion:The use of aromatherapy with lavender is more effective than PMR therapy in reducing the anxiety level of patients undergoing spinal anesthesia.Due to the high level of anxiety and its serious effects on the patient’s hemodynamics,aromatherapy with lavender can be used as an easy and cheap method to reduce anxiety in operation rooms. 展开更多
关键词 ANXIETY AROMATHERAPY lavender essential oil MASSAGE progressive muscle relaxation spinal anesthesia vital signs
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Photoelectric State with Long-Term Relaxation in CdTe:(Ag, Cu, Cd) and Sb2Se3:Se Photovoltaic Films
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作者 Ozodbek Ravshanboy o‘g‘li Nurmatov Dilkhumor Tolibjonovna Mamadieva Nosirjon Khaydarovich Yuldashev 《Journal of Applied Mathematics and Physics》 2024年第1期43-51,共9页
The results of an experimental study of long-term relaxation of the photoelectret state of polycrystalline CdTe:(Ag, Cu, Cd) and Sb<sub>2</sub>Se<sub>3</sub>:Se films with an anomalous photovol... The results of an experimental study of long-term relaxation of the photoelectret state of polycrystalline CdTe:(Ag, Cu, Cd) and Sb<sub>2</sub>Se<sub>3</sub>:Se films with an anomalous photovoltaic property are presented. In such films, the residual photovoltage is caused by the separation of photocarriers by the built-in electrostatic field of the near-surface region of space charges and their asymmetric capture by deep levels of impurities or complexes, including impurity atoms and intrinsic defects, both in the bulk and on the surface of crystal grains. It has been shown that in activated films, a two-step exponential temporary relaxation of the initial photovoltage of the order of V<sub>APV</sub> ≈ (500-600) V is detected, and only 10% of it experiences long-term relaxation (t ≈ 100-120 min). 展开更多
关键词 Thin Polycrystalline Films Doping Deep Centers Anomalous Photovoltage Photoelectret State Long-Term relaxation
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Improved Algorithm for Efficient Extraction of Relaxation Parameter Values from Wideband Permittivity of Baijiu
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作者 Haoyan Yu Qi Jin +1 位作者 Zhaozong Meng Zhen Li 《Instrumentation》 2024年第1期62-69,共8页
The complex permittivity of baijiu varies with frequency,and dielectric spectroscopy has been used to evaluate the quality.To simplify the analysis and reduce the number of the parameters,a dielectric relaxation model... The complex permittivity of baijiu varies with frequency,and dielectric spectroscopy has been used to evaluate the quality.To simplify the analysis and reduce the number of the parameters,a dielectric relaxation model is often used to fit the permittivity data.However,existing fitting methods such as the least squares and particle swarm optimization methods are often computationally complex and require preset initial values.Therefore,a simpler calculation method of the relaxation parameters considering the geometric characteristics of the permittivity spectrum is proposed.It is based on the relationship between the Cole-Cole relaxation parameters and the Cole-Cole diagram,which is fitted by a geometric method.First,the concepts of the Cole-Cole parameters and the diagram are introduced,and then the process of obtaining the parameters from the complex permittivity measurement data is explained.Taking baijiu with 56%alcohol by volume(ABV)as an example,the fitting is better than the least squares method and similar to the particle swarm optimization.This method is then used for the parameter fitting of baijiu with ABV of 42-52%,and the average error is less than 1%,demonstrating its wider applicability.Finally,a prediction model is used for baijiu with 53%ABV,and the error is only 1.51%.Hence,the method can be applied to the measurement of ABV of baijiu. 展开更多
关键词 PERMITTIVITY cole-cole equation relaxation parameters alcohol by volume baijiu
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Effects of relaxation breathing exercise on fatigue and cortisol level among Indonesian gynecological cancer patients undergoing chemotherapy:a pilot study
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作者 Mulhaeriah Mulhaeriah Mohammad Syafar Sangkala +1 位作者 Syahrul Syahrul Rezki Wahyuni 《Frontiers of Nursing》 2024年第2期201-208,共8页
Objective:This study aimed to determine the effect of the relaxation breathing exercise(RBE)on fatigue and cortisol levels among Indonesian women with gynecological cancer undergoing chemotherapy.Methods:This pilot st... Objective:This study aimed to determine the effect of the relaxation breathing exercise(RBE)on fatigue and cortisol levels among Indonesian women with gynecological cancer undergoing chemotherapy.Methods:This pilot study consecutively recruited 44 gynecological cancer patients to receive RBE(22)or usual care(22).Cortisol level was measured before and after completion of the intervention(day 8).Fatigue was measured using the Piper Fatigue Scale(PFS).Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale(HADS)at the baseline days of the study for days 1,4,and 8.The obtained data were analyzed using Fisher’s exact test,the independent t-test,and the Mann-Whitney U test.Results:There were significant increases in cortisol levels within the groups,either the intervention or control groups,respectively(P-value=0.0003 and 0.001).Despite there being no statistical significance between the intervention and control groups,there were noticeable differences in the cortisol levels,indicating the extreme increase in cortisol levels in the control group(Median[IQR1-IQR3]:2.30[0.99-9.09];Min-Max:0.43-23.38)compared with the intervention group(Median[IQR1-IQR3]=2.97[1.26-5.18];Min-Max=0.39-6.91).Conclusions:RBE helps prevent a significant increase in cortisol levels that can alleviate fatigue for women with gynecological cancer.Further research was recommended to compare several intervention modalities for fatigue and cancer-related symptom management based on cortisol level changes. 展开更多
关键词 ANXIETY CORTISOL FATIGUE gynecological cancer relaxation breathing exercise
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A Bibliometric Study on The Application of Progressive Muscle Relaxation Training in The Nursing Field in China
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作者 Chengwen Shi Feifan Zhao +4 位作者 Yingshuo Wang Chengxuan Liu Aiyu Mao Siqi Ji Ruixiao Lu 《Journal of Clinical and Nursing Research》 2024年第4期14-21,共8页
Objective:To systematically analyze the research status and application of progressive muscle relaxation training(PMRT)in the nursing field in China,and provide a reference basis for scientific research in this field.... Objective:To systematically analyze the research status and application of progressive muscle relaxation training(PMRT)in the nursing field in China,and provide a reference basis for scientific research in this field.Methods:The bibliometric method was adopted in“progressive muscle relaxation training”or“PMRT,”and“nursing.”The established database was included in the China National Knowledge Infrastructure(CNKI)and the Wanfang Medical Network.The relevant articles in the Chinese Science and Technology Periodical Database(VIP)were analyzed.Results:A total of 169 literatures were included.The journals,years,and regions of literature publication were uneven,mainly originating from the eastern region(43.19%),and listed the application of progressive muscle relaxation training in the field of nursing in China.Intervention literature information was mainly dominated by experimental studies(97%).Conclusion:The related research and application of progressive muscle relaxation training in nursing in China is increasing,but there is a lack of objective evaluation of outcome indicators and a short intervention period.Further research should be conducted in the future to effectively guide the development of PMRT in the field of nursing in China. 展开更多
关键词 Progressive muscle relaxation training Nursing practice BIBLIOMETRICS
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Effects of Progressive Muscle Relaxation Training on Anxiety, Depression, and Quality of Life in Patients with Cerebral Small Vessel Disease
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作者 Chengwen Shi Feifan Zhao +3 位作者 Yingshuo Wang Chengxuan Liu Aiyu Mao Siqi Jin 《Journal of Clinical and Nursing Research》 2024年第5期283-292,共10页
Objective:To explore the effects of progressive muscle relaxation training on anxiety,depression,and quality of life in patients with cerebral small vessel disease(CSVD).Methods:Sixty-one patients with CSVD in the Dep... Objective:To explore the effects of progressive muscle relaxation training on anxiety,depression,and quality of life in patients with cerebral small vessel disease(CSVD).Methods:Sixty-one patients with CSVD in the Department of Neurology of a tertiary hospital were divided into an observation group(28 patients)and a control group(33 patients)by lottery method.The control group received conventional nursing care,while the observation group received progressive muscle relaxation training interventions in addition to the conventional care.The Hamilton Anxiety Scale(HAMA),the Hamilton Depression Scale(HAMD),and the Stroke-Specific Quality of Life Scale(SS-QOL)were used to compare the effects before the intervention,7 days after the intervention,and 30 days after the intervention.Results:Over time,at different time points after the intervention,the anxiety and depression scores of patients with CSVD in the observation group were significantly lower than those in the control group(P<0.05).The quality of life scores were significantly higher in the observation group compared to the control group(P<0.05),and these differences were statistically significant.Conclusion:Progressive muscle relaxation training can improve anxiety and depression in patients with cerebral small vessel disease and can effectively enhance their quality of life. 展开更多
关键词 Progressive muscle relaxation training Cerebral small vessel disease(CSVD) ANXIETY DEPRESSION Quality of life
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LIQUID-GAS COEXISTENCE EQUILIBRIUM IN A RELAXATION MODEL 被引量:1
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作者 王平 唐少强 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2005年第6期767-773,共7页
Stability of liquid-gas coexistence equilibrium in a relaxation model for isothermal phase transition in a sealed one-dimensional tube was discussed. With matched asymptotic expansion, a linear system for first order ... Stability of liquid-gas coexistence equilibrium in a relaxation model for isothermal phase transition in a sealed one-dimensional tube was discussed. With matched asymptotic expansion, a linear system for first order perturbations was derived formally. By solving this system analytically, it is shown that small initial perturbations are damped out in general; yet they may maintain at certain level for special cases. Numerical evidence is presented. This manifests the regularization effects of relaxation. 展开更多
关键词 phase transition relaxation matched asymptotic expansion
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Functional group resolved NMR relaxation of 3-carbon adsorbates in mesoporous alumina 被引量:1
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作者 Neil Robinson Carmine D’Agostino Michael LJohns 《Magnetic Resonance Letters》 2023年第3期248-255,I0004,共9页
NMR relaxation analysis provides a unique and non-invasive probe of fluid dynamics within porous materials,and may be applied to the interpretation of a wide variety of material and interfacial characteristics.Here,we... NMR relaxation analysis provides a unique and non-invasive probe of fluid dynamics within porous materials,and may be applied to the interpretation of a wide variety of material and interfacial characteristics.Here,we report two-dimensional^(1)H T_(1)-T_(2)relaxation correlation measurements of a range of three-carbon adsorbates(1-propanol,2-propanol and propanoic acid)imbibed within the mesoporous metal oxide gamma-alumina.Our data,acquired across field strengths of 2 MHz,12.7 MHz and 43 MHz,clearly reveal two populations in each measurement,identified as the alkyl and hydroxyl moieties of each adsorbate.These results expand the range of materials in which such functional group resolved relaxation is known to occur,and demonstrate the clear persistence of such phenomena using a range of typical benchtop NMR systems employed to study fluid-saturated porous media. 展开更多
关键词 NMR relaxation ADSORPTION Porous media Low-field NMR
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The dynamic relaxation form finding method aided with advanced recurrent neural network 被引量:1
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作者 Liming Zhao Zhongbo Sun +1 位作者 Keping Liu Jiliang Zhang 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第3期635-644,共10页
How to establish a self‐equilibrium configuration is vital for further kinematics and dynamics analyses of tensegrity mechanism.In this study,for investigating tensegrity form‐finding problems,a concise and efficien... How to establish a self‐equilibrium configuration is vital for further kinematics and dynamics analyses of tensegrity mechanism.In this study,for investigating tensegrity form‐finding problems,a concise and efficient dynamic relaxation‐noise tolerant zeroing neural network(DR‐NTZNN)form‐finding algorithm is established through analysing the physical properties of tensegrity structures.In addition,the non‐linear constrained opti-misation problem which transformed from the form‐finding problem is solved by a sequential quadratic programming algorithm.Moreover,the noise may produce in the form‐finding process that includes the round‐off errors which are brought by the approximate matrix and restart point calculating course,disturbance caused by external force and manufacturing error when constructing a tensegrity structure.Hence,for the purpose of suppressing the noise,a noise tolerant zeroing neural network is presented to solve the search direction,which can endow the anti‐noise capability to the form‐finding model and enhance the calculation capability.Besides,the dynamic relaxation method is contributed to seek the nodal coordinates rapidly when the search direction is acquired.The numerical results show the form‐finding model has a huge capability for high‐dimensional free form cable‐strut mechanisms with complicated topology.Eventually,comparing with other existing form‐finding methods,the contrast simulations reveal the excellent anti‐noise performance and calculation capacity of DR‐NTZNN form‐finding algorithm. 展开更多
关键词 dynamic relaxation form‐finding noise‐tolerant zeroing neural network sequential quadratic programming TENSEGRITY
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Data-driven optimization study of the multi-relaxation-time lattice Boltzmann method for solid-liquid phase change 被引量:1
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作者 Yanlin REN Zhaomiao LIU +1 位作者 Zixiao KANG Yan PANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第1期159-172,共14页
Sharp phase interfaces and accurate temperature distributions are important criteria in the simulation of solid-liquid phase changes.The multi-relaxation-time lattice Boltzmann method(MRT-LBM)shows great numerical per... Sharp phase interfaces and accurate temperature distributions are important criteria in the simulation of solid-liquid phase changes.The multi-relaxation-time lattice Boltzmann method(MRT-LBM)shows great numerical performance during simulation;however,the value method of the relaxation parameters needs to be specified.Therefore,in this study,a random forest(RF)model is used to discriminate the importance of different relaxation parameters to the convergence,and a support vector machine(SVM)is used to explore the decision boundary of the convergent samples in each dimensional model.The results show that the convergence of the samples is consistent with the sign of the decision number,and two types of the numerical deviations appear,i.e.,the phase mushy zone and the non-physical heat transfer.The relaxation parameters chosen on the decision boundary can further suppress the numerical bias and improve numerical accuracy. 展开更多
关键词 solid-liquid phase change lattice Boltzmann method(LBM) relaxation parameter random forest(RF) support vector machine(SVM)
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Synchronization coexistence in a Rulkov neural network based on locally active discrete memristor
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作者 马铭磷 谢小华 +2 位作者 杨阳 李志军 孙义闯 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第5期705-709,共5页
At present, many neuron models have been proposed, which can be divided into discrete neuron models and continuous neuron models. Discrete neuron models have the advantage of faster simulation speed and the ease of un... At present, many neuron models have been proposed, which can be divided into discrete neuron models and continuous neuron models. Discrete neuron models have the advantage of faster simulation speed and the ease of understanding complex dynamic phenomena. Due to the properties of memorability, nonvolatility, and local activity, locally active discrete memristors(LADMs) are also suitable for simulating synapses. In this paper, we use an LADM to mimic synapses and establish a Rulkov neural network model. It is found that the change of coupling strength and the initial state of the LADM leads to multiple firing patterns of the neural network. In addition, considering the influence of neural network parameters and the initial state of the LADM, numerical analysis methods such as phase diagram and timing diagram are used to study the phase synchronization. As the system parameters and the initial states of the LADM change, the LADM coupled Rulkov neural network exhibits synchronization transition and synchronization coexistence. 展开更多
关键词 locally active discrete memristor(LADM) Rulkov synchronization coexistence
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Coexistence of giant Rashba spin splitting and quantum spin Hall effect in H–Pb–F
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作者 薛文明 李金 +3 位作者 何朝宇 欧阳滔 戴雄英 钟建新 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期414-418,共5页
Rashba spin splitting(RSS)and quantum spin Hall effect(QSHE)have attracted enormous interest due to their great significance in the application of spintronics.In this work,we theoretically proposed a new two-dimension... Rashba spin splitting(RSS)and quantum spin Hall effect(QSHE)have attracted enormous interest due to their great significance in the application of spintronics.In this work,we theoretically proposed a new two-dimensional(2D)material H–Pb–F with coexistence of giant RSS and quantum spin Hall effec by using the ab initio calculations.Our results show that H–Pb–F possesses giant RSS(1.21 eV·A)and the RSS can be tuned up to 4.16 e V·A by in-plane biaxial strain,which is a huge value among 2D materials.Furthermore,we also noticed that H–Pb–F is a 2D topological insulator(TI)duo to the strong spin–orbit coupling(SOC)interaction,and the large topological gap is up to 1.35 e V,which is large enough for for the observation of topological edge states at room temperature.The coexistence of giant RSS and quantum spin Hall effect greatly broadens the potential application of H–Pb–F in the field of spintronic devices. 展开更多
关键词 coexistence Rashba spin splitting quantum spin Hall effect spin–orbit coupling
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Unusual magnetic relaxation in a single-molecule magnet with toroidal magnetic moments
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作者 苏丹 张义权 +1 位作者 刘恩克 孙阳 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期446-449,共4页
We report the synthesis and characterization of a single-molecule magnet composed of triangular clusters of dysprosium ions.The structural study shows that the symmetry changes from one polar point group(mm2)at room t... We report the synthesis and characterization of a single-molecule magnet composed of triangular clusters of dysprosium ions.The structural study shows that the symmetry changes from one polar point group(mm2)at room temperature to another polar point group(m)at low temperature.Magnetic studies and theory calculations illustrate that the vortex distribution of magnetic dipoles in the triangular dysprosium clusters forms a toroidal magnetic moment.Interestingly,the analysis of AC magnetic susceptibility reveals the coexistence of three distinct magnetic relaxation processes,corresponding to the Raman,Orbach,and QTM relaxation pathways,respectively.The sum of three modified Debye functions is successfully used to describe the multiple relaxation behavior. 展开更多
关键词 single-molecule magnet magnetic relaxation toroidal moment
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Relaxation of Ne^(1+)1s^(0)2s^(2)2p^(6)np produced by resonant excitation of an ultraintense ultrafast x-ray pulse
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作者 闫杰 刘彦鹏 +4 位作者 侯永 高城 吴建华 曾交龙 袁建民 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期75-79,共5页
The creation and relaxation of double K-hole states 1s^(0)2s^(2)2p^(6)np(n≥3)of Ne^(1+)in the interaction with ultraintense ultrafast x-ray pulses are theoretically investigated.The x-ray photon energies are selected... The creation and relaxation of double K-hole states 1s^(0)2s^(2)2p^(6)np(n≥3)of Ne^(1+)in the interaction with ultraintense ultrafast x-ray pulses are theoretically investigated.The x-ray photon energies are selected so that x-rays first photoionize1s^(22)s^(22)p^(6) of a neon atom to create a single K-hole state of 1s2s^(22)p^(6) of Ne^(1+),which is further excited resonantly to double K-hole states of ls^(0)2s^(2)2p^(6)np(n≥3).A time-dependent rate equation is used to investigate the creation and relaxation processes of 1s^(0)2s^(2)2p^(6)np,where the primary microscopic atomic processes including photoexcitation,spontaneous radiation,photoionization and Auger decay are considered.The calculated Auger electron energy spectra are compared with recent experimental results,which shows good agreement.The relative intensity of Auger electrons is very sensitive to the photon energy and bandwidth of x-ray pulses,which could be used as a diagnostic tool for x-ray free electron laser and atom experiments. 展开更多
关键词 hollow atoms x-ray resonant excitation relaxation
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Some of the Mechanisms for Coexistence of Tree Species Diversity in Tropical Forests: A Review of Effects of Tree Density Dependence
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作者 Oladele Fisayo Falade 《Open Journal of Forestry》 2023年第1期132-144,共13页
Tree communities contribute to maintenance of species diversity in tropical forests. Coexistence of many tree species is not without competition. Therefore, coexistence of tree species and size diversities occur seque... Tree communities contribute to maintenance of species diversity in tropical forests. Coexistence of many tree species is not without competition. Therefore, coexistence of tree species and size diversities occur sequentially or simultaneously in tropical natural forests. Understanding coexistence and competition mechanisms of tree species requires knowledge of interactions within and between species. However, many conservation efforts and strategies failed due to inability to identify and maintain functional coexistence mechanisms among tree species in the forest. Also, most trees died because of pressure on their habitats and not because of limiting growth resources. Hence, species identity, minimum distance and size of the neighbouring trees which are responsible for coexistence of competing trees in most tropical forests have not been explicitly reviewed. Therefore, this review evaluated some of the density dependent mechanisms for coexistence of tree species alpha diversity in tropical forests. Many interactive mechanisms are responsible for coexistence tree species in tropical forests. Inter- and intra-specific competitions are the most significant and both facilitate positive and negative density dependence. Therefore, switching from negative to positive density dependence may occur in some situations. Positive and negative density effects regulate species abundance and coexistence through conspecific and heterospecific structures. Aggregates of conspecific and heterospecific neighbours constitute forest spatial structure. Negative density interactions are mutually exclusive and basically ranged from effect of species identity of neighbours, distance to neighbours and tree size of the neighbours to reference trees in the community structures. Some mechanisms shorten distances for heterospecific than conspecific interactions. Conspecific structures improved survival and growth of rare tree species. Interactive mechanisms in tree community and population structures facilitate species diversity and size inequality, respectively. 展开更多
关键词 Tree Community Structure Tree Species Diversity Tree Species coexistence Tree Populations
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GLOBAL SOLUTIONS TO A HYDRODYNAMIC MODEL FOR SEMICONDUCTORS WITH VELOCITY RELAXATION
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作者 王先婷 陆云光 +1 位作者 Richard De la cruz 尤国桥 《Acta Mathematica Scientia》 SCIE CSCD 2023年第2期975-980,共6页
In this paper,we apply the method given in the paper“Zero relaxation time limits to a hydrodynamic model of two carrier types for semiconductors”(Mathematische Annalen,2022,382:1031–1046)to study the Cauchy problem... In this paper,we apply the method given in the paper“Zero relaxation time limits to a hydrodynamic model of two carrier types for semiconductors”(Mathematische Annalen,2022,382:1031–1046)to study the Cauchy problem for a one dimensional inhomogeneous hydrodynamic model of two-carrier types for semiconductors with the velocity relaxation. 展开更多
关键词 global L solution hydrodynamic model two-carrier types velocity relaxation
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Inferring Human-elephant Coexistence Based on Characteristics of Human-elephant Interactions in Nangunhe of Yunnan,China
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作者 WANG Jiahui CHEN Ying +2 位作者 SUN Yakuan LYU Zhuoluo SHI Kun 《Chinese Geographical Science》 SCIE CSCD 2023年第2期363-376,共14页
Human-wildlife conflict(HWC)negatively impacts both humans and wildlife.Attitudes of local residents have been critical in promoting wildlife conservation.It is therefore necessary to understand the characteristics of... Human-wildlife conflict(HWC)negatively impacts both humans and wildlife.Attitudes of local residents have been critical in promoting wildlife conservation.It is therefore necessary to understand the characteristics of HWC and identify influential factors on attitudes towards conservation to implement conservation strategies efficiently.This research focused on features of human-elephant interactions,while attitudes and values regarding the small population of Asian elephants(Elephas maximus)in Nangunhe National Nature Reserve(NNR),Yunnan,China.The total of 327 valid questionnaires were gathered around the area where Asian elephants were distributed.Logistic regression models were employed to analyze the correlations among five predictor variables(‘Area’,‘Family size’,‘Annual income’,‘Quantity of family members in non-primary industries’and‘Experiencing loss or not’)and three response variables(‘Attitude towards elephants’,‘Perception of the values of elephants’and‘Attitude towards tourism development’).The study area was densely forested with tea plants,rubber trees,corns and sugarcane.There,25.99%of respondents reported the experience of human-elephant conflict(HEC),with crop raiding and cash crop damages being the major conflict types.To demonstrate respect for elephants and to mitigate HEC,a unique custom called‘Giving tribute to elephants’was developed long ago.Respondents’township with an official annual festival of‘Giving Tribute to Elephants’(odds ratio(OR)=2.75,P=1.73×10^(-6))and higher annual income(OR=2.09,P=5.45×10^(-5))significantly contributed to forming a more positive attitude towards elephants,whereas HEC itself have contributed to a more negative attitude(OR=0.50,P=3.29×10^(-3)).Therefore,we propose that:1)reducing human-elephant conflict by testing multiple mitigation measures and adopting the most effective one of them;2)enhancing local livelihoods through the development of ecological products and ecotourism;and 3)preserving and developing the Wa culture in this region.The study area deserves more attention and further research to explore and obtain endorsement from the public to achieve coexistence between human and wildlife. 展开更多
关键词 Asian elephant(Elephas maximus) Wa people human-elephant conflict coexistence Nangunhe National Nature Reserve YUNNAN China
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Protection and Restoration of Soil and Water Ecology to Achieve Harmonious Coexistence between Human and Nature
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作者 SUN Fazheng 《Journal of Landscape Research》 2023年第1期60-62,共3页
At present,the ecological environment crisis of global concern,such as climate warming and biodiversity loss,the fundamental reason is the change and destruction of the earth's soil and water ecology.Therefore,pro... At present,the ecological environment crisis of global concern,such as climate warming and biodiversity loss,the fundamental reason is the change and destruction of the earth's soil and water ecology.Therefore,protecting and restoring the authenticity,diversity,cleanliness and integrity of soil and water ecology,we should coordinate and deal with the relationship between human beings and soil and water ecology,and realize the harmonious coexistence between human beings and nature from the three aspects of protecting natural soil and water ecology,protecting and restoring natural soil and water ecology,building and regenerating artificial soil and water ecology. 展开更多
关键词 Soil and water ecology PROTECTION RESTORATION Harmonious coexistence
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