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Synthesis of CoFe2O4/Graphene Oxide-Grafted Tetraethylenepentamine for Removal of Cr (VI) from Aqueous Solution CoFe2O4/氧化石墨烯接枝四乙基戊二胺的合成及其对水溶液中Cr (VI)的去除
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-05-13 DOI: 10.1155/2022/8961039
H. Pan, Donglin Zhao, Li Wang
In this study, amino-functionalized magnetic graphene-based composite TEPA-GO/CoFe2O4 (TGOM) was prepared by a simple one-step hydrothermal reaction and applied to the removal of Cr (VI) from wastewater. The removal of Cr (VI) by TGOM has the characteristics of high removal efficiency and excellent cycle performance. The maximum adsorption capacity is 114.81 mg/g, and the adsorption efficiency can still reach 62% after four cycles. The mass percentage of amino in TGOM material is about 1.97% according to thermogravimetric analysis. The modification by TEPA increased the adsorption sites and improved the adsorption capacities due to the synergistic effect of chelation with Cr (VI). The effects of pH, contact time, and temperature on the removal of Cr (VI) were studied. The removal process accorded with the pseudo-second-order kinetics and Langmuir isotherm model, and the thermodynamic parameters showed that the adsorption process was exothermic and spontaneous. The characterization analysis before and after adsorption showed that there were complexation reaction, electrostatic adsorption, and reduction mechanism in the removal process. The above results indicate that TGOM is an effective adsorption material for the removal of Cr (VI) in wastewater.
本研究采用简单的一步水热反应制备了氨基功能化磁性石墨烯基复合材料TEPA-GO/CoFe2O4 (TGOM),并将其应用于废水中Cr (VI)的去除。TGOM脱除Cr (VI)具有脱除效率高、循环性能优异的特点。最大吸附量为114.81 mg/g,循环4次后吸附效率仍可达62%。热重分析表明,TGOM材料中氨基酸的质量百分比约为1.97%。经TEPA改性后,由于与Cr (VI)的螯合协同作用,增加了吸附位点,提高了吸附能力,研究了pH、接触时间和温度对Cr (VI)去除的影响。吸附过程符合拟二级动力学和Langmuir等温线模型,热力学参数表明吸附过程是自发放热的。吸附前后的表征分析表明,在去除过程中存在络合反应、静电吸附和还原机理。上述结果表明,TGOM是一种去除废水中Cr (VI)的有效吸附材料。
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引用次数: 1
Oxygen Dependence of Formation, Electronic State Transition, and Spin Polarization for Anatase TiO2: A Comprehensive Study 锐钛矿型TiO2形成、电子态跃迁和自旋极化的氧依赖性研究
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-04-11 DOI: 10.1155/2022/4709525
L. Shan, R. Fan, Y. Sun, F. M. Zhang, G. Zhang, G. Qin
The stability, geometry, microstructure, and specie combination together with the electronic states of the anatase TiO2 with oxygen defect content of 0%, 3.125%, 6.25%, and 12.5% have been intensively studied within the framework of the density functional theory method. The results show that the TiO2 with an oxygen defect is not as stable as intrinsic TiO2. The compound formation enthalpy Ef and the oxygen defect formation energy value tend to be larger for a higher defect content, and the oxygen defect gets harder to be formed. The bonds within the TiO6 polyhedron are different and not geometrically symmetrical. The bond strengths show distinct diversity, and the primitive cell of anatase TiO2 show spatial expansion when there are oxygen defects. All bands moved down to the low energy region, and two impurity energy band levels emerged for the anatase TiO2 with oxygen defect. The energy band gap is decreased from 3.085 eV to 1.165 eV, 1.0015 eV, and 0.43 eV. There are generally 7 peaks for the spin density of states function, corresponding to their 5 main bands. For the anatase TiO2 with an oxygen defect content of 12.5%, the spin density of states functions are not horizontal ordinate symmetrical near −1.12 eV and 0.31 eV. They are formed by oxygen defect energy levels, which is the result of the Ti d and O p state electron polarization. Transitions from weak paramagnetic to antiferromagnetic are found for the anatase TiO2 with oxygen defect.
在密度泛函理论的框架下,对氧缺陷含量分别为0%、3.125%、6.25%和12.5%的锐钛矿型TiO2的稳定性、几何结构、微观结构、物种组合以及电子态进行了深入研究。结果表明,含氧缺陷的TiO2不像固有TiO2那样稳定。缺陷含量越高,化合物生成焓Ef和氧缺陷生成能值越大,氧缺陷越难形成。TiO6多面体内的键是不同的,不是几何对称的。钛矿型TiO2的结合强度表现出明显的多样性,当存在氧缺陷时,钛矿型TiO2的原始细胞表现出空间扩张。所有能带都向下移动到低能区,氧缺陷的锐钛矿TiO2出现了两个杂质能带。能带隙由3.085 eV减小到1.165 eV、1.0015 eV和0.43 eV。态函数的自旋密度一般有7个峰,对应于它们的5个主能带。对于氧缺陷含量为12.5%的锐钛矿TiO2,在- 1.12 eV和0.31 eV附近,态函数的自旋密度不是横坐标对称的。它们是由氧缺陷能级形成的,这是tid和op态电子极化的结果。含氧缺陷的锐钛矿TiO2由弱顺磁性向反铁磁性转变。
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引用次数: 0
Adsorption of Water Molecule in Graphene/MoS2 Heterostructure with Vacancy Defects in Mo Sites 含Mo空位缺陷的石墨烯/MoS2异质结构对水分子的吸附
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-04-11 DOI: 10.1155/2022/2135213
H. K. Neupane, N. Adhikari
First-principle calculations based on the spin-polarized density functional theory (DFT) with vdW corrections by DFT-D2 approach have been carried out to study structural, electronic, and magnetic properties of water-adsorbed graphene/MoS2 heterostructures (system-I), and water-adsorbed graphene/MoS2 heterostructures with vacancy defects in Mo sites (systems-II). We consider vacancy defects in different Mo sites such as centre-1Mo atom vacancy defect (system-IIa), left-1Mo atom vacancy defect (system-IIb), and 2Mo atom vacancy defects (system-IIc). All the systems considered in this study are structurally stable; however, the stability of defected systems decreases with an increase in defect concentrations. The calculated binding energies of HS used in this study agree with the reported work. Electronic properties of system-I and systems-II reveal that they have metallic characteristics. Our investigation shows that system-I is nonmagnetic and systems-II are magnetic. The magnetic moment in the defected systems (system-IIa, system-IIb, and system-IIc) is developed by unpaired up and down-spins of electrons created in the orbitals of atoms due to vacancy defects in Mo atoms.
基于自旋极化密度泛函理论(DFT)的第一性原理计算,通过DFT- d2方法进行了vdW修正,研究了水吸附石墨烯/MoS2异质结构(系统i)和Mo空位缺陷的水吸附石墨烯/MoS2异质结构(系统ii)的结构、电子和磁性能。我们考虑了不同Mo位的空位缺陷,如中心1mo原子空位缺陷(system-IIa)、左1mo原子空位缺陷(system-IIb)和2Mo原子空位缺陷(system-IIc)。本研究中考虑的所有系统都是结构稳定的;然而,缺陷系统的稳定性随着缺陷浓度的增加而降低。本文所用HS的结合能计算结果与文献报道一致。系统i和系统ii的电子性质表明它们具有金属特征。我们的研究表明,系统i是非磁性的,系统ii是磁性的。缺陷体系(system-IIa, system-IIb和system-IIc)的磁矩是由Mo原子的空位缺陷在原子轨道上产生的电子不配对的上下自旋产生的。
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引用次数: 1
Quantum Dot Phase Transition Simulation with Hybrid Quantum Annealing via Metropolis-Adjusted Stochastic Gradient Langevin Dynamics 基于大都市调节随机梯度朗之万动力学的混合量子退火量子点相变模拟
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-04-11 DOI: 10.1155/2022/9711407
Shiba Kodai, Ryo Sugiyama, Koichi Yamaguchi, Tomah Sogabe
We report a hybrid quantum-classical simulation approach for simulating the optical phase transition observed experimentally in the ultrahigh-density type-II InAs quantum dot array. A hybrid simulation scheme, which contains stochastic gradient Langevin dynamics (a well-known Bayesian machine learning algorithm for big data) along with adiabatic quantum annealing, is developed to reproduce the experimentally observed phase transition. By implementing the simulation scheme into a quantum circuit, we successfully verified the phase transition observed in the experiment. Our work demonstrates for the first time the feasibility of hybridizing quantum computation with classical Langevin dynamics for the analysis of carrier dynamics and quantum phase transition of the quantum dot.
本文报道了一种混合量子-经典模拟方法,用于模拟实验中观察到的超高密度ii型InAs量子点阵列的光学相变。采用随机梯度朗之万动力学(一种著名的大数据贝叶斯机器学习算法)与绝热量子退火相结合的混合模拟方案,再现了实验观察到的相变。通过在量子电路中实现模拟方案,我们成功地验证了实验中观察到的相变。我们的工作首次证明了将量子计算与经典朗之万动力学相结合用于量子点载流子动力学和量子相变分析的可行性。
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引用次数: 0
AlGaN/GaN Heterostructure Schottky Barrier Diodes with Graded Barrier Layer 具有梯度势垒层的AlGaN/GaN异质结构肖特基势垒二极管
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-04-06 DOI: 10.1155/2022/5885992
Honghui Liu, Z. Liang, C. Yan, Yuebo Liu, Fengge Wang, Yanyan Xu, Junyu Shen, Z. Xiao, Zhisheng Wu, Yang Liu, Qi Wang, Xinqiang Wang, Baijun Zhang
The AlGaN/GaN Schottky barrier diodes (SBDs) working as high-power mixer and multiplier show great potential in millimeter wave (MMW) field owing to their high breakdown voltage. Nevertheless, its further application is severely limited by large reverse leakage current (Jr) since the two-dimensional electron gas (2DEG) channel is hard to be pinched off at low voltage. To address this limitation, a graded AlGaN/GaN heterostructure is introduced to extend the 2DEG channel into a quasi-three-dimensional electron slab. By comparing the fixed Al composition AlGaN/GaN SBD, Jr of the graded AlGaN/GaN SBD is significantly reduced due to the extension of channel carriers, confirming the effective Jr suppression effect of this structure. Furthermore, on this basis, a recessed anode structure is utilized to expect a smaller Jr. The results indicated that the graded AlGaN/GaN SBDs with air-bridge structure have achieved a pretty low Jr value (1.6 × 10−13 A at -15 V), and its cutoff frequency is as high as 60.6 GHz. It is expected that such SBDs with low Jr have significant advantages in future applications.
AlGaN/GaN肖特基势垒二极管(sdd)作为大功率混频器和乘法器,由于其高击穿电压,在毫米波(MMW)领域显示出巨大的潜力。然而,由于二维电子气(2DEG)通道在低电压下难以被掐断,其反向泄漏电流(Jr)大,严重限制了其进一步应用。为了解决这一限制,引入了梯度AlGaN/GaN异质结构,将2DEG通道扩展为准三维电子板。通过比较固定Al组成AlGaN/GaN SBD,分级AlGaN/GaN SBD的Jr由于通道载流子的扩展而显著降低,证实了该结构有效的Jr抑制效果。结果表明,采用气桥结构的梯度AlGaN/GaN sdd具有较低的Jr值(在-15 V时为1.6 × 10−13 a),截止频率高达60.6 GHz。预计这种低Jr的sbd在未来的应用中具有显著的优势。
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引用次数: 0
Study on the Adsorption Characteristics of Mo-Doped Graphene on the Decomposition Products of SF6 Substitute Gas Based on First-Principle Calculations 基于第一性原理计算的掺钼石墨烯对SF6替代气体分解产物的吸附特性研究
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-03-27 DOI: 10.1155/2022/7740210
Can Ding, Xing Hu, Lu Feng
C4F7N, C5F10O, etc., as new environmental-friendly alternative gases decompose under partial discharge and produce a series of products such as CO, CF4, C2F6, C3F8, CF3CN, C2F5CN, and COF2. Based on the first-principles calculation method of density functional theory (DFT), the adsorption characteristics of intrinsic state graphene and Mo-doped graphene adsorbing SF6 and its substitute gas decomposition products are calculated and analyzed. By comparing the adsorption energy, adsorption distance, density of state, Mulliken charge population, charge transfer amount, and molecular orbital energy for adsorbing different decomposition gases, it can be seen that the system structure is the most stable when Mo is doped at the T site of the graphene surface. The adsorption of Mo-doped graphene on gas molecules is significantly stronger than that of intrinsic graphene, and the order of adsorption is: SO2F2 > H2S > SO2 > CF4. The adsorption of H2S gas molecules by intrinsic state and Mo-doped graphene is n-type adsorption, while the adsorption of SO2F2, CF4, and SO2 gas molecules is p-type adsorption. Mo-doped graphene can be used as a detection device for SO2F2 gas resistance sensors.
C4F7N、c5f100等新型环保替代气体在部分排放下分解,生成CO、CF4、C2F6、C3F8、CF3CN、C2F5CN、COF2等系列产品。基于密度泛函理论(DFT)第一性原理计算方法,计算分析了本征态石墨烯和掺钼石墨烯对SF6及其替代气体分解产物的吸附特性。通过比较吸附不同分解气体的吸附能、吸附距离、态密度、Mulliken电荷居群、电荷转移量、分子轨道能,可以看出,在石墨烯表面T位掺杂Mo时,体系结构最稳定。掺钼石墨烯对气体分子的吸附明显强于本征石墨烯,吸附顺序为:SO2F2 > H2S > SO2 > CF4。本征态和掺钼石墨烯对H2S气体分子的吸附为n型吸附,而对SO2F2、CF4和SO2气体分子的吸附为p型吸附。掺钼石墨烯可作为SO2F2气体电阻传感器的检测器件。
{"title":"Study on the Adsorption Characteristics of Mo-Doped Graphene on the Decomposition Products of SF6 Substitute Gas Based on First-Principle Calculations","authors":"Can Ding, Xing Hu, Lu Feng","doi":"10.1155/2022/7740210","DOIUrl":"https://doi.org/10.1155/2022/7740210","url":null,"abstract":"C4F7N, C5F10O, etc., as new environmental-friendly alternative gases decompose under partial discharge and produce a series of products such as CO, CF4, C2F6, C3F8, CF3CN, C2F5CN, and COF2. Based on the first-principles calculation method of density functional theory (DFT), the adsorption characteristics of intrinsic state graphene and Mo-doped graphene adsorbing SF6 and its substitute gas decomposition products are calculated and analyzed. By comparing the adsorption energy, adsorption distance, density of state, Mulliken charge population, charge transfer amount, and molecular orbital energy for adsorbing different decomposition gases, it can be seen that the system structure is the most stable when Mo is doped at the T site of the graphene surface. The adsorption of Mo-doped graphene on gas molecules is significantly stronger than that of intrinsic graphene, and the order of adsorption is: SO2F2 > H2S > SO2 > CF4. The adsorption of H2S gas molecules by intrinsic state and Mo-doped graphene is n-type adsorption, while the adsorption of SO2F2, CF4, and SO2 gas molecules is p-type adsorption. Mo-doped graphene can be used as a detection device for SO2F2 gas resistance sensors.","PeriodicalId":7382,"journal":{"name":"Advances in Condensed Matter Physics","volume":"20 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83289987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Electric Modulus Analysis of (1 − x) PbMg1/3Nb2/3O3-(x)K1/2Bi1/2TiO3 Ceramics (1−x) PbMg1/3Nb2/3O3-(x)K1/2Bi1/2TiO3陶瓷的电模量分析
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-03-22 DOI: 10.1155/2022/2450578
K. Legesse, Vijaya Bhaskar Rao Poluri, Elangovan Sampandam
Ferroelectrics refer to groups of dielectrics having the property of spontaneous polarization. Lead magnesium niobate-potassium bismuth titanate ((1 − x) PbMg1/3Nb2/3O3-(x)K1/2Bi1/2TiO3)) x = 0.15, 0.25, and 0.35 are prepared by solid-state reaction rout technique. The electric modulus of the prepared samples is studied using the complex impedance spectroscopic method at 400°C, 450°C, and 500°C in various frequency ranges. In the lower frequency range, the real modulus (M′ (ω)) decreased with increasing the temperature. Furthermore, the real modulus (M′ (ω)) increased with increasing frequency and the concentration of the doping component. The imaginary modulus (M″ (ω)) increased with increasing the temperature. The significant variations in the real and imaginary coefficients signify the existence of thermally activated dielectric relaxation between the selected components. Moreover, the magnitude of grain capacitance increased with increasing the temperature, confirming the negative temperature coefficient of resistance of the material.
铁电体是指具有自发极化特性的介电体群。采用固相反应路由技术制备了铌镁铅-钛酸铋钾((1−x) pbm1 / 3nb2 / 3o3 -(x)K1/2Bi1/2TiO3) x = 0.15、0.25和0.35。采用复阻抗谱法对制备的样品在400°C、450°C和500°C不同频率范围内的电模量进行了研究。在低频范围内,实模量(M′(ω))随温度的升高而减小。实模量(M′(ω))随掺杂频率和掺杂浓度的增加而增加。虚模量(M″(ω))随温度的升高而增大。实系数和虚系数的显著变化表明在所选组分之间存在热激活的介电弛豫。晶粒电容的大小随温度的升高而增大,证实了材料的电阻温度系数为负。
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引用次数: 0
Study of the Effect of Quenching on Microstructural and Magnetic Properties of Cu-Doped Mg-Ferrite 淬火对cu掺杂mg -铁氧体组织和磁性能影响的研究
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-02-27 DOI: 10.1155/2022/3354087
Apurba Poddar, Suman Halder, S. I. Liba, S. M. Hoque, S. S. Sikder
Mg1-xCuxFe2O4 (x = 0.0–0.5) was prepared by the double sintering ceramic method, which sintered at 1100°C and 1200°C for 3 hours and investigated for structural, microstructural, and magnetic properties as a function of the Cu content and cooling process. XRD analysis of 1100°C sintered samples revealed that all the samples were crystallized in a single-phase cubic spinal structure. The microstructural and magnetic properties of slow cooled (furnace-cooled) and fast cooled (quenched) Mg-Cu ferrites have been studied using the scanning electron microscope (SEM), vibrating sample magnetometer (VSM), and Mössbauer spectroscopy after sintering at 1200°C. Homogeneous coaxial grains did not form for any furnace-cooled samples, while for the quenched sample, homogeneous grains were clearly visible even without doping with Cu. Substantial grain growth was witnessed by the samples with higher copper content for both cooling conditions, whereas quenched samples possessed a smaller grain size compared to furnace-cooled samples. The saturation magnetization experienced a higher value for quenched samples compared to furnace-cooled samples with increasing Cu content except for x = 0.4. The sextet pattern of Mössbauer spectroscopy confirmed all the samples were ferromagnetic in nature. Chemical shift, quadrupole shift, hyperfine field, and site occupancy of Fe3+ were also obtained using Mössbauer spectroscopy.
采用双烧结法制备了Mg1-xCuxFe2O4 (x = 0 ~ 0.5),分别在1100℃和1200℃下烧结3 h,研究了Cu含量和冷却工艺对Mg1-xCuxFe2O4组织、显微组织和磁性能的影响。1100℃烧结试样的XRD分析表明,所有试样均呈单相立方脊状结晶。采用扫描电镜(SEM)、振动样品磁强计(VSM)和Mössbauer谱仪研究了慢冷(炉冷)和快冷(淬火)Mg-Cu铁氧体在1200℃烧结后的显微组织和磁性能。炉内冷却后的样品均未形成均匀的同轴晶粒,而淬火后的样品即使不掺杂Cu,也能清晰地看到均匀的晶粒。在两种冷却条件下,具有较高铜含量的样品都有明显的晶粒生长,而淬火样品的晶粒尺寸比炉冷样品小。除x = 0.4外,随着Cu含量的增加,淬火样品的饱和磁化强度高于炉冷样品。Mössbauer光谱的六重模式证实了所有样品都是铁磁性的。利用Mössbauer光谱法还得到了Fe3+的化学位移、四极位移、超精细场和位占用。
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引用次数: 1
Evolution of Microstructure during Rapid Solidification of SiC under High Pressure SiC在高压下快速凝固过程中的组织演变
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-02-23 DOI: 10.1155/2022/7823211
Wanjun Yan, X. Qin, Zhongzheng Zhang, C. Zhang, T. Gao
The microstructure evolution of liquid silicon carbide (SiC) during rapid solidification under different pressure values is simulated with the Tersoff potential using molecular dynamics. The structure evolution characteristics of SiC are analyzed by considering the pair distribution function, bond angle distribution, coordination number, and the diagrams of the microstructure during rapid solidification. The results show that the average energy of atoms gradually increases with pressure. When the pressure reaches 100 GPa, the average energy of the atom is greater than the average energy of the atom in the initial liquid state. Under different pressures, the diffusion of atoms tends to remain stable at a temperature of about 3700 K. The application of pressure has a major impact on the arrangement of atoms, except on the third-nearest neighbor, while the impact on the nearest neighbor and the second-nearest neighbor is relatively small. The pressure increases the medium-range order of the system. The coordination numbers of Si and C atoms gradually decrease with the decrease in temperature and increase in pressure. Pressure changes the microstructure of the SiC amorphous system after solidification, and the density can be increased by adjusting the coordination number of atoms. As the pressure increases, the SiC amorphous system exhibits a dense structure with coordination numbers of 4, 5, 6, and 7.
采用分子动力学方法,利用Tersoff势模拟了不同压力值下液态碳化硅(SiC)快速凝固过程中的组织演变。结合对分布函数、键角分布、配位数和快速凝固组织图,分析了SiC的组织演变特征。结果表明,原子的平均能量随压力的增大而逐渐增大。当压力达到100gpa时,原子的平均能量大于初始液态原子的平均能量。在不同压力下,原子的扩散在3700 K左右的温度下趋于稳定。压力的施加对原子的排列有很大的影响,除了对第三近邻的影响,而对最近近邻和第二近邻的影响相对较小。压力增加了系统的中量程阶。随着温度的降低和压力的增大,Si和C原子的配位数逐渐降低。压力改变了SiC非晶体系凝固后的微观结构,通过调整原子配位数可以提高密度。随着压力的增加,SiC非晶体系呈现出配位数为4、5、6和7的致密结构。
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引用次数: 2
Equation of State Determination for Rhenium Using First-Principles Molecular Dynamics Calculations and High-Pressure Experiments 用第一性原理分子动力学计算和高压实验确定铼的状态方程
IF 1.5 4区 物理与天体物理 Q3 PHYSICS, CONDENSED MATTER Pub Date : 2022-02-18 DOI: 10.1155/2022/7545777
S. Ono
The room-temperature bulk modulus of rhenium (Re) was measured in the pressure range 0 to 115 GPa using a laser-annealing diamond anvil cell and the synchrotron X-ray diffraction method. Thermal properties of Re were investigated up to 4000 K based on first-principles molecular dynamics calculations, and the equation of state for Re was determined using experimental and calculated data. A Vinet equation of state fitted to the 300 K data yielded a bulk modulus of KT0 = 384 GPa and a pressure derivative of K T 0 ′  = 3.26. The contribution of thermal pressure was determined to have the form ΔPth = [αKT(Va) + (∂KT/∂T)Vln(Va/V)]ΔT. When αKT(Va) was assumed to be constant, the fit to the data yielded αKT(Va) = 0.0056 GPa/K. In contrast, the volume dependence of the thermal pressure was very small, and fitting yielded a value of (∂KT/∂T)V = −0.00042.
在0 ~ 115 GPa的压力范围内,采用激光退火金刚石砧池和同步x射线衍射法测量了铼(Re)的室温体积模量。基于第一性原理分子动力学计算研究了Re在4000 K温度下的热性能,并利用实验和计算数据确定了Re的状态方程。用Vinet状态方程拟合300 K的数据,得到体积模量KT0 = 384 GPa,压力导数KT0 ' = 3.26。确定热压力的贡献形式为ΔPth = [αKT(Va) +(∂KT/∂T)Vln(Va/V)]ΔT。当αKT(Va)不变时,拟合得到αKT(Va) = 0.0056 GPa/K。相比之下,热压的体积依赖性非常小,拟合的值为(∂KT/∂T)V =−0.00042。
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引用次数: 1
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