The Experts below are selected from a list of 31275 Experts worldwide ranked by ideXlab platform
Jiaoxia Zhang - One of the best experts on this subject based on the ideXlab platform.
-
thermomechanical investigation on the effect of nitroguanidine on the Thermal Expansion Coefficient and glass transition temperature of double base gun propellant
Journal of materials research and technology, 2019Co-Authors: Jiahao Liang, Zhongliang Xiao, Jiaoxia Zhang, Mengyao Dong, Zhanhu Guo, Jincheng Fan, Tao DingAbstract:Abstract Thermal Expansion Coefficient (CTE) is a critical parameter of gun propellant because of its major role in fabrication, storage and combustion performance of the propellant. Further, controlling the CTE of the propellant is an effective solution to improve its loading density. Therefore, it is important to understand the Thermal Expansion of the propellant. To obtain the linear CTE of insensitive gun propellant, different weight percentages of NQ are added to the B# double-base absorbent propellant, the Thermal mechanical analyzer (TMA) is employed to estimate their dimensional change over the temperature range of 213–323 K. The pure NQ flaky gun propellant exhibits a negative Thermal Expansion with a linear CTE of −2.006 × 10−4 mm/mm K−1. The results show that the linear CTE of the B# double-base absorbent propellant is decreased by 53.74% as the concentration of NQ is increased to 30%, whereas the glass transition temperature increases with increasing the NQ content.
-
experimental study on Thermal Expansion Coefficient of composite multi layered flaky gun propellants
Composites Part B-engineering, 2019Co-Authors: Taixin Liang, Le Qi, Zhongliang Xiao, Jiaoxia Zhang, Tao Ding, Yang Wang, Na LuAbstract:Abstract Improving the burning progressivity is an effective approach to improve the muzzle velocities of projectile of a gun. Composite multi-layered flaky gun propellant is a combination of a fast-burning inner layer and a slow-burning outer layer. It has an obvious burning progressivity which decreases the pressure in bore and increases the muzzle velocity, thus this characteristic is widely concerned by the research of gun propellant. The Thermal Expansion Coefficient of composite multi-layered gun propellant has a significant influence on the combustion performance. Therefore, understanding the Thermal Expansion properties of the composite multi-layered gun propellant is important. In this study, the Thermal Expansion Coefficients were measured by Thermal mechanical analyzer (TMA) for a three-layered flaky gun propellant, and the influence of laminating and coating flaky gun propellant on Thermal Expansion Coefficient was investigated. The results showed that the slow-burning layers had a higher Thermal Expansion Coefficient than the faster-burning layers, the Thermal Expansion Coefficient of slow-burning layers was 4–5 times bigger than that of fast-burning layers, and the order of magnitudes was 1 × 10−5 K−1. The laminating and coating had a great influence on the Thermal Expansion Coefficient of flaky gun propellant, the Thermal Expansion Coefficient of laminate sample was 10 times greater than that of the original sample, and the order of magnitudes for two layers and three layers propellant reached 1 × 10−4 K−1. Furthermore, the theoretical relations between the Thermal Expansion Coefficient of axial and the Thermal Expansion Coefficient of the fast and slow burning layer were derived.
Shibing Tian - One of the best experts on this subject based on the ideXlab platform.
-
Thermal Expansion Coefficient of few layer mos2 studied by temperature dependent raman spectroscopy
Scientific Reports, 2021Co-Authors: Zhongtao Lin, Shibing Tian, Ke Zhu, Wuguo Liu, Yuan Huang, Yang YangAbstract:The 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.
-
Temperature-dependent Raman investigation on suspended graphene: Contribution from Thermal Expansion Coefficient mismatch between graphene and substrate
Carbon, 2016Co-Authors: Shibing Tian, Ruhao Pan, Yu-guang Yang, Changzhi Gu, Zhe Liu, Chao Wang, Junjie LiAbstract:Dedicated Raman investigation was performed on the graphene suspended on the round holes, compared with graphene supported on Si/SiO2substrate, in the temperature range from 173 K to 673 K. We observed an unexpected result that the temperature-dependent Raman frequency shift of suspended graphene was similar as that of supported graphene. This evidenced that the strain caused by Thermal Expansion Coefficient mismatch between graphene and substrate cannot be neglected from suspended graphene. We predicted that the unsupported graphene zone and its surrounding graphene that adhered to substrate should be considered as a whole while studying the thermodynamic properties of this suspended graphene, and thus a semi-quantitative factor was introduced to the estimate the contribution from substrate to the suspended graphene, explaining well this result. Our results suggest that the Thermal Expansion Coefficient mismatch induced strain should be taken into consideration in the study of electronic and transport properties of suspended graphene devices, in which the self-heating effect cannot be eliminated during operation.
Tao Ding - One of the best experts on this subject based on the ideXlab platform.
-
thermomechanical investigation on the effect of nitroguanidine on the Thermal Expansion Coefficient and glass transition temperature of double base gun propellant
Journal of materials research and technology, 2019Co-Authors: Jiahao Liang, Zhongliang Xiao, Jiaoxia Zhang, Mengyao Dong, Zhanhu Guo, Jincheng Fan, Tao DingAbstract:Abstract Thermal Expansion Coefficient (CTE) is a critical parameter of gun propellant because of its major role in fabrication, storage and combustion performance of the propellant. Further, controlling the CTE of the propellant is an effective solution to improve its loading density. Therefore, it is important to understand the Thermal Expansion of the propellant. To obtain the linear CTE of insensitive gun propellant, different weight percentages of NQ are added to the B# double-base absorbent propellant, the Thermal mechanical analyzer (TMA) is employed to estimate their dimensional change over the temperature range of 213–323 K. The pure NQ flaky gun propellant exhibits a negative Thermal Expansion with a linear CTE of −2.006 × 10−4 mm/mm K−1. The results show that the linear CTE of the B# double-base absorbent propellant is decreased by 53.74% as the concentration of NQ is increased to 30%, whereas the glass transition temperature increases with increasing the NQ content.
-
experimental study on Thermal Expansion Coefficient of composite multi layered flaky gun propellants
Composites Part B-engineering, 2019Co-Authors: Taixin Liang, Le Qi, Zhongliang Xiao, Jiaoxia Zhang, Tao Ding, Yang Wang, Na LuAbstract:Abstract Improving the burning progressivity is an effective approach to improve the muzzle velocities of projectile of a gun. Composite multi-layered flaky gun propellant is a combination of a fast-burning inner layer and a slow-burning outer layer. It has an obvious burning progressivity which decreases the pressure in bore and increases the muzzle velocity, thus this characteristic is widely concerned by the research of gun propellant. The Thermal Expansion Coefficient of composite multi-layered gun propellant has a significant influence on the combustion performance. Therefore, understanding the Thermal Expansion properties of the composite multi-layered gun propellant is important. In this study, the Thermal Expansion Coefficients were measured by Thermal mechanical analyzer (TMA) for a three-layered flaky gun propellant, and the influence of laminating and coating flaky gun propellant on Thermal Expansion Coefficient was investigated. The results showed that the slow-burning layers had a higher Thermal Expansion Coefficient than the faster-burning layers, the Thermal Expansion Coefficient of slow-burning layers was 4–5 times bigger than that of fast-burning layers, and the order of magnitudes was 1 × 10−5 K−1. The laminating and coating had a great influence on the Thermal Expansion Coefficient of flaky gun propellant, the Thermal Expansion Coefficient of laminate sample was 10 times greater than that of the original sample, and the order of magnitudes for two layers and three layers propellant reached 1 × 10−4 K−1. Furthermore, the theoretical relations between the Thermal Expansion Coefficient of axial and the Thermal Expansion Coefficient of the fast and slow burning layer were derived.
Igor S. Burmistrov - One of the best experts on this subject based on the ideXlab platform.
-
quantum elasticity of graphene Thermal Expansion Coefficient and specific heat
Physical Review B, 2016Co-Authors: I. V. Gornyi, Igor S. Burmistrov, V. Yu. Kachorovskii, Mikhail I. Katsnelson, Alexander D. MirlinAbstract:We explore thermodynamics of a quantum membrane, with a particular application to suspended graphene membrane and with a particular focus on the Thermal Expansion Coefficient. We show that an interplay between quantum and classical anharmonicity-controlled fluctuations leads to unusual elastic properties of the membrane. The effect of quantum fluctuations is governed by the dimensionless coupling constant, g(0) 0) and is equal to similar or equal to 0.05 for graphene. We demonstrate that the Thermal Expansion Coefficient alpha(T) of the membrane is negative and remains nearly constant down to extremely low temperatures, T-0 proportional to exp(-2/g(0)). We also find that alpha(T) diverges in the classical limit: alpha(T) proportional to -ln(1/g(0)) for g(0) -> 0. For graphene parameters, we estimate the value of the Thermal Expansion Coefficient as alpha(T) similar or equal to -0.23 eV(-1), which applies below the temperature T-uv similar to g(0)x(0) similar to 500K(where x(0) similar to 1 eV is the bending rigidity) down to T-0 similar to 10(-1)4 K. For T < T-0, the Thermal Expansion Coefficient slowly (logarithmically) approaches zero with decreasing temperature. This behavior is surprising since typically the Thermal Expansion Coefficient goes to zero as a power-law function. We discuss possible experimental consequences of this anomaly. We also evaluate classical and quantum contributions to the specific heat of the membrane and investigate the behavior of the Gruneisen parameter.
-
quantum elasticity of graphene Thermal Expansion Coefficient and specific heat
Physical Review B, 2016Co-Authors: I. V. Gornyi, Igor S. Burmistrov, Mikhail I. Katsnelson, Yu V Kachorovskii, Alexander D. MirlinAbstract:We explore thermodynamics of a quantum membrane, with a particular application to suspended graphene membrane and with a particular focus on the Thermal Expansion Coefficient. We show that an interplay between quantum and classical anharmonicity-controlled fluctuations leads to unusual elastic properties of the membrane. The effect of quantum fluctuations is governed by the dimensionless coupling constant, ${g}_{0}\ensuremath{\ll}1$, which vanishes in the classical limit $(\ensuremath{\hbar}\ensuremath{\rightarrow}0)$ and is equal to $\ensuremath{\simeq}0.05$ for graphene. We demonstrate that the Thermal Expansion Coefficient ${\ensuremath{\alpha}}_{T}$ of the membrane is negative and remains nearly constant down to extremely low temperatures, ${T}_{0}\ensuremath{\propto}exp(\ensuremath{-}2/{g}_{0})$. We also find that ${\ensuremath{\alpha}}_{T}$ diverges in the classical limit: ${\ensuremath{\alpha}}_{T}\ensuremath{\propto}\ensuremath{-}ln(1/{g}_{0})$ for ${g}_{0}\ensuremath{\rightarrow}0$. For graphene parameters, we estimate the value of the Thermal Expansion Coefficient as ${\ensuremath{\alpha}}_{T}\ensuremath{\simeq}\ensuremath{-}0.23\phantom{\rule{0.28em}{0ex}}{\mathrm{eV}}^{\ensuremath{-}1}$, which applies below the temperature ${T}_{\mathrm{uv}}\ensuremath{\sim}{g}_{0}{\ensuremath{\varkappa}}_{0}\ensuremath{\sim}500$ K (where ${\ensuremath{\varkappa}}_{0}\ensuremath{\sim}1$ eV is the bending rigidity) down to ${T}_{0}\ensuremath{\sim}{10}^{\ensuremath{-}14}$ K. For $Tl{T}_{0}$, the Thermal Expansion Coefficient slowly (logarithmically) approaches zero with decreasing temperature. This behavior is surprising since typically the Thermal Expansion Coefficient goes to zero as a power-law function. We discuss possible experimental consequences of this anomaly. We also evaluate classical and quantum contributions to the specific heat of the membrane and investigate the behavior of the Gr\"uneisen parameter.
Zhongliang Xiao - One of the best experts on this subject based on the ideXlab platform.
-
thermomechanical investigation on the effect of nitroguanidine on the Thermal Expansion Coefficient and glass transition temperature of double base gun propellant
Journal of materials research and technology, 2019Co-Authors: Jiahao Liang, Zhongliang Xiao, Jiaoxia Zhang, Mengyao Dong, Zhanhu Guo, Jincheng Fan, Tao DingAbstract:Abstract Thermal Expansion Coefficient (CTE) is a critical parameter of gun propellant because of its major role in fabrication, storage and combustion performance of the propellant. Further, controlling the CTE of the propellant is an effective solution to improve its loading density. Therefore, it is important to understand the Thermal Expansion of the propellant. To obtain the linear CTE of insensitive gun propellant, different weight percentages of NQ are added to the B# double-base absorbent propellant, the Thermal mechanical analyzer (TMA) is employed to estimate their dimensional change over the temperature range of 213–323 K. The pure NQ flaky gun propellant exhibits a negative Thermal Expansion with a linear CTE of −2.006 × 10−4 mm/mm K−1. The results show that the linear CTE of the B# double-base absorbent propellant is decreased by 53.74% as the concentration of NQ is increased to 30%, whereas the glass transition temperature increases with increasing the NQ content.
-
experimental study on Thermal Expansion Coefficient of composite multi layered flaky gun propellants
Composites Part B-engineering, 2019Co-Authors: Taixin Liang, Le Qi, Zhongliang Xiao, Jiaoxia Zhang, Tao Ding, Yang Wang, Na LuAbstract:Abstract Improving the burning progressivity is an effective approach to improve the muzzle velocities of projectile of a gun. Composite multi-layered flaky gun propellant is a combination of a fast-burning inner layer and a slow-burning outer layer. It has an obvious burning progressivity which decreases the pressure in bore and increases the muzzle velocity, thus this characteristic is widely concerned by the research of gun propellant. The Thermal Expansion Coefficient of composite multi-layered gun propellant has a significant influence on the combustion performance. Therefore, understanding the Thermal Expansion properties of the composite multi-layered gun propellant is important. In this study, the Thermal Expansion Coefficients were measured by Thermal mechanical analyzer (TMA) for a three-layered flaky gun propellant, and the influence of laminating and coating flaky gun propellant on Thermal Expansion Coefficient was investigated. The results showed that the slow-burning layers had a higher Thermal Expansion Coefficient than the faster-burning layers, the Thermal Expansion Coefficient of slow-burning layers was 4–5 times bigger than that of fast-burning layers, and the order of magnitudes was 1 × 10−5 K−1. The laminating and coating had a great influence on the Thermal Expansion Coefficient of flaky gun propellant, the Thermal Expansion Coefficient of laminate sample was 10 times greater than that of the original sample, and the order of magnitudes for two layers and three layers propellant reached 1 × 10−4 K−1. Furthermore, the theoretical relations between the Thermal Expansion Coefficient of axial and the Thermal Expansion Coefficient of the fast and slow burning layer were derived.