scholarly journals Thermal expansion coefficient of monolayer MoS2 determined using temperature-dependent Raman spectroscopy combined with finite element simulations

2021 ◽  
Author(s):  
Yang Yang ◽  
Zhongtao Lin ◽  
Renfei Li ◽  
Yutong Li ◽  
Wuguo Liu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Finite Element ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Finite Element Simulations ◽  
Monolayer Mos2 ◽  
Temperature Dependent

scholarly journals Thermal expansion coefficient of few-layer MoS2 studied by temperature-dependent Raman spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhongtao Lin ◽  
Wuguo Liu ◽  
Shibing Tian ◽  
Ke Zhu ◽  
Yuan Huang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Negative Thermal Expansion ◽  
Thermal Parameter ◽  
Temperature Dependent ◽  
Bending Vibrations ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

AbstractThe thermal expansion coefficient is an important thermal parameter that influences the performance of nanodevices based on two-dimensional materials. To obtain the thermal expansion coefficient of few-layer MoS2, suspended MoS2 and supported MoS2 were systematically investigated using Raman spectroscopy in the temperature range from 77 to 557 K. The temperature-dependent evolution of the Raman frequency shift for suspended MoS2 exhibited prominent differences from that for supported MoS2, obviously demonstrating the effect due to the thermal expansion coefficient mismatch between MoS2 and the substrate. The intrinsic thermal expansion coefficients of MoS2 with different numbers of layers were calculated. Interestingly, negative thermal expansion coefficients were obtained below 175 K, which was attributed to the bending vibrations in the MoS2 layer during cooling. Our results demonstrate that Raman spectroscopy is a feasible tool for investigating the thermal properties of few-layer MoS2 and will provide useful information for its further application in photoelectronic devices.

Size- and temperature-dependent Young's modulus and size-dependent thermal expansion coefficient of thin films

2016 ◽  
Vol 18 (31) ◽  
pp. 21508-21517 ◽  
Author(s):  
Xiao-Ye Zhou ◽  
Bao-Ling Huang ◽  
Tong-Yi Zhang
Keyword(s):  
Thin Films ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Material Properties ◽  
Essential Role ◽  
Young's Modulus ◽  
Temperature Dependent ◽  
Size Dependent

Surfaces of nanomaterials play an essential role in size-dependent material properties.

scholarly journals Volumetric Properties in the NaAsO2 + H2O System at Temperature from 283.15 to 363.15 K and Atmospheric Pressure

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Hongfang Hou ◽  
Wanjing Cui ◽  
Jiaojiao Chen ◽  
Lingzong Meng ◽  
Yafei Guo ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Molar Volume ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Apparent Molar Volume ◽  
Correlation Coefficients ◽  
Apparent Molar Volumes ◽  
Temperature Dependent ◽  
Molar Volumes ◽  
Experimental Values

Densities of sodium arsenite (NaAsO2) aqueous solution with the molality varied from 0.19570 to 1.94236 mol·kg−1 at temperature intervals of 5 K from 283.15 to 363.15 K and 101 ± 5 kPa were measured by a precise Anton Paar Digital vibrating-tube densimeter. Apparent molar volumes (VΦ) and thermal expansion coefficient (α) were obtained on the basis of experimental data. The 3D diagram of apparent molar volume against temperature and molality and the diagram of thermal expansion coefficient against molality were generated. According to the Pitzer ion-interaction equation of the apparent molar volume model, the Pitzer single-salt parameters (βM,X0υ, βM,X1υ, βM,X2υ, and CM,Xυ, MX = NaAsO2) and their temperature-dependent correlation F(i, p, T) = a1 + a2ln (T/298.15) + a3(T − 298.15) + a4/(620 − T) + a5/(T − 227) (where T is temperature in Kelvin and ai are the correlation coefficients) for NaAsO2 were obtained for the first time. The predictive apparent molar volumes agree well with the experimental values, and those results indicated that the single-salt parameters and the temperature-dependent formula are reliable.

Compositional Design of Ceramic Extrusion Die Materials Based on the Residual Stress Analyses in the Die Manufacturing Process

2011 ◽  
Vol 291-294 ◽  
pp. 1709-1712
Author(s):  
Chong Hai Xu ◽  
Jing Jie Zhang ◽  
Zhen Yu Jiang ◽  
Ming Dong Yi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Extrusion Die ◽  
Element Simulation ◽  
Die Material ◽  
Longitudinal Cracks ◽  
Ceramic Extrusion

In the die manufacturing process of ceramic extrusion die, the residual stress was produced resulted from the thermal expansion coefficient mismatch between ceramic die and die core of graphite. As a result, the longitudinal cracks were formed in the ceramic extrusion die. The thermal residual stress formed in the cooling process was analyzed by finite element simulation method. The result indicated that the thermal expansion coefficient was the primary factor which could affect the tensile stress of ceramic extrusion die. Then, the thermal expansion coefficient, elastic modulus and poisson's ratio of ceramic extrusion die material were selected as design variables, and the largest tensile stress that less than allowable stress of ceramic die material was determined as the objective function, the material component were optimized according to the finite element simulation. The longitudinal cracks were eventually avoided.

Robustness of Residual Stresses in Castings and an Improved Process Window

2009 ◽  
Author(s):  
Magnus Hofwing ◽  
Niclas Stro¨mberg
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Thermal Expansion ◽  
Monte Carlo Simulations ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Young's Modulus ◽  
Process Window ◽  
Quadratic Response

In this work the robustness of residual stresses in finite element simulations with respect to deviations in mechanical parameters in castings is evaluated. Young’s modulus, the thermal expansion coefficient and the hardening are the studied parameters. A 2D finite element model of a stress lattice is used. The robustness is evaluated by comparing purely finite element based Monte Carlo simulations and Monte Carlo simulations based on linear and quadratic response surfaces. Young’s modulus, the thermal expansion coefficient and the hardening are assumed to be normal distributed with a standard deviation that is 10% of their nominal value at different temperatures. In this work an improved process window is also suggested to show the robustness graphically. By using this window it is concluded that least robustness is obtained for high hardening values in combination to deviations in Young’s modulus and the thermal expansion coefficient. It is also concluded that quadratic response surface based Monte Carlo simulations substitute finite element based Monte Carlo simulations satisfactory. Furthermore, the standard deviation of the responses are evaluated analytically by using the Gauss formula, and are compared to results from Monte Carlo simulations. The analytical solutions are accurate as long as the Gauss formula is not utilized close to a stationary point.

scholarly journals Thermal Expansion Coefficient of Monolayer Molybdenum Disulfide Using Micro-Raman Spectroscopy

Nano Letters ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 4745-4751 ◽  
Author(s):  
Lenan Zhang ◽  
Zhengmao Lu ◽  
Youngsup Song ◽  
Lin Zhao ◽  
Bikram Bhatia ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Expansion ◽  
Molybdenum Disulfide ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Micro Raman Spectroscopy
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