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133 results on '"Yang, Meng-Lin"'

27. Effects of chemical composition on the structural stability, elastic, vibrational, and electronic properties of Cs2NaLnX6 (Ln = La...Lu, X = F, Cl, Br, I) elpasolites.

Author

Wu, Bing, Yang, Meng‐Lin, Yan, Yan‐Ci, Ma, Chong‐Geng, Zhang, Hong‐Wu, Brik, Mikhail G., Dramićanin, Miroslav D., Valiev, Uygun V., and Piasecki, Michal

Subjects
*CHEMICAL stability, *RARE earth ions, *ELASTIC constants, *NUCLEAR nonproliferation, *ATOMIC number, *CESIUM compounds, *RARE earth metals
Abstract

Elpasolite crystals are very important materials, both from the applied and fundamental points of view. Those elpasolites, which contain rare earth ions with a high atomic number Z, are very much suitable for the low‐cost high‐performance gamma‐ray detection, applications in medicine, food industry, nuclear energy production, processing, and detection of nuclear proliferation. The thermal and structural stabilities are important parameters required for detecting applications, because the performance conditions for such devices are usually very harsh. Since it is widely believed that elpasolites may have even better detection properties, the lack of systematic studies on the elpasolites and thus the unavailability of reliable data on their physical properties and trends in their variation caused by chemical composition considerably hinders search for more efficient new materials. Therefore, to fill in this gap and provide with all essential information about a large number of elpasolites crystals, for the first time, the structural stability, elastic, vibrational, and electronic properties of 60 cubic elpasolite Cs2NaLnX6 (Ln = La, ..., Lu, X = F, Cl, Br, I) crystals were consistently calculated in the framework of the same computational approach based on the density functional theory (DFT). Variation of all calculated parameters (such as the lattice constants, elastic constants, Debye temperature, normal vibrational modes frequencies, Mulliken effective charges, bond populations, and band gaps) across the considered groups of crystals was analyzed and several trends, which are important for the search and preparation of new stable materials with improved performance, were identified. [ABSTRACT FROM AUTHOR]

Published
2021
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36. Heat capacity and phase transitions of 2-amino-2-hydroxymethylpropan-1,3-diol from 290 K to 455 K

Author

Zhang Zhi Ying and Yang Meng Lin

Subjects
Phase transition, Melting temperature, Diol, Enthalpy, Analytical chemistry, Thermodynamics, Heat capacity, Atomic and Molecular Physics, and Optics, Calorimeter, chemistry.chemical_compound, chemistry, General Materials Science, Physical and Theoretical Chemistry, Adiabatic process
Abstract

The heat capacity of 2-amino-2-hydroxymethylpropan-1,3-diol was measured from 290 K to its melting temperature by means of an automated adiabatic calorimeter. A bifurcated solid-to-solid transition was found for the compound with the temperatures of the maxima occurring at (407.44 ± 0.01) K and (407.56 ± 0.01) K, and with a molar transition enthalpy of (33.42 ± 0.21) kJ · mol −1 . In addition, the melting temperature and molar enthalpy of melting for the compound were determined to be (443.6 ± 0.1) K and (2.41 ± 0.17) kJ · mol −1 , respectively.

Published
1990

42. Effects of melt overheating degree on undercooling degree and amorphous forming of Nd9Fe85–xTi4C2Bx(x=10, 12) magnetic alloys

Author

YANG, Meng-lin, PAN, Jing, LIU, Xin-cai, XIAO, Xiao-yan, and ZHAN, Yu-yong

Abstract

The effects of melt overheating degree on the undercooling degree and resultant solidification structures of Nd9Fe85–xTi4C2Bx(x=10, 12) glass-forming alloys were studied by differential thermal analysis combining with solidification structure analysis. The results indicate that the undercooling degree of Nd9Fe85–xTi4C2Bx(x=10, 12) alloys significantly increases with the rise of melt overheating degree, and two overheating degree thresholds corresponding to the drastic increase of the mean undercooling degree are found for each of the alloys. The existence of two turning points of the mean undercooling degrees can be linked to the structure transitions inside the overheated melts, which result in the evident increase of volume fraction of amorphous phase in the solidified structures.

Published
2016
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46. Study on thermal conductivity of porous silicon thermal isolation layer based on micro-structure mathematical model

Author

Hu Ming, Yang Meng-Lin, Xu Lu-Jia, Yang Hai-Bo, and Zhang Jie

Subjects
Thermal conductivity, Materials science, Silicon, chemistry, Scattering, General Physics and Astronomy, chemistry.chemical_element, Composite material, Conductivity, Microstructure, Porosity, Thermal conduction, Porous silicon
Abstract

Porous silicon can be used as a thermal isolation layer because of its low thermal conductivity. Different from other models based on the mechanism that the thermal conductivity of porous silicon is attributed to complex microcosmic thermal conductivity through such as boundary scattering, the model used in this paper is based on the mechanism that the low conductivity of the porous silicon material is due to its structure factors, such as the existence and distribution of pores and porous silicon is viewed as a compound microstructure piece, which is constructed by both silicon continuous material and pore continuous material medium, connecting in parallel and series patterns. Therefore, the authors give a more understandable and simpler reason why the conductivity of such a material is at such a low level. It is pointed out that the influence of porosity on equivalent thermal conductivity can be divided into two parts: vertical and horizontal, thereby giving semi-quantitative relationships between the porosity and equivalent thermal conductivity for different pore structures and distributions. A comparison between the calculated results and experimental results shows the validity of this model, thus supporting the reason why the thermal conductivity of porous silicon material is relatively low.

Published
2010

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