Chunli Ma

Publications (4)9.88 Total impact

• Article: The acoustic velocity, refractive index, and equation of state of liquid ammonia dihydrate under high pressure and high temperature.

  Chunli Ma, Xiaoxin Wu, Fengxian Huang, Qiang Zhou, Fangfei Li, Qiliang Cui
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  ABSTRACT: High-pressure and high-temperature Brillouin scattering studies have been performed on liquid of composition corresponding to the ammonia dihydrate stoichiometry (NH(3)[middle dot]2H(2)O) in a diamond anvil cell. Using the measured Brillouin frequency shifts from 180° back- and 60° platelet-scattering geometries, the acoustic velocity, refractive index, density, and adiabatic bulk modulus have been determined under pressure up to freezing point along the 296, 338, 376, and 407 K isotherms. Along these four isotherms, the acoustic velocities increase smoothly with increasing pressure but decrease with the increased temperature. However, the pressure dependence of the refractive indexes on the four isotherms exhibits a change in slope around 1.5 GPa. The bulk modulus increases linearly with pressure and its slope, dB∕dP, decreases from 6.83 at 296 K to 4.41 at 407 K. These new datasets improve our understanding of the pressure- and temperature-induced molecular structure changes in the ammonia-water binary system.
  The Journal of chemical physics 09/2012; 137(10):104504. · 3.09 Impact Factor
• Article: In situ observation of multiple phase transitions in low-melting ionic liquid [BMIM][BF4] under high pressure up to 30 GPa.

  Lei Su, Xiang Zhu, Zheng Wang, Xuerui Cheng, Yongqiang Wang, Chaosheng Yuan, Zhenping Chen, Chunli Ma, Fangfei Li, Qiang Zhou, Qiliang Cui
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  ABSTRACT: In situ characterization of phase transitions and direct microscopic observations of a low-melting ionic liquid, 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF(4)]), has been performed in detail by Raman spectroscopy. Compression of [BMIM][BF(4)] was measured under hydrostatic pressure up to ~30.0 GPa at room temperature by using a high-pressure diamond anvil cell. With pressure increasing, the characteristic bands of [BMIM][BF(4)] displayed nonmonotonic pressure-induced frequency shifts, and it is found to undergo four successive phase transitions at around 2.25, 6.10, 14.00, and 21.26 GPa. Especially, above a pressure of 21.26 GPa, luminescence of the sample occurs, which is connected with the most significant phase transition at around this pressure. It was indicated that the structure change under high pressure might be associated with a conformational change in the butyl chain. Upon releasing pressure, the spectrum was not recovered under a pressure up to 1.16 GPa, thereby indicating that this high-pressure phase remains stable over a large pressure range between 30 and 1.16 GPa in low-melting ionic liquid [BMIM][BF(4)]. Although the sample was kept under the normal pressure for 24 h, the spectrum was recovered, and it showed that the phase transition of [BMIM][BF(4)] was reversible. In other words, such a low-melting ionic liquid [BMIM][BF(4)] remains stable even after being treated under so a high pressure of up to 30 GPa.
  The Journal of Physical Chemistry B 02/2012; 116(7):2216-22. · 3.70 Impact Factor
• Source

  Available from: Hongyang Zhu

  Article: High-Pressure Behaviors of SrF2 Nanocrystals with Two Morphologies

  Jingshu Wang, ‡ Hongyang Zhu, † Chunli Ma, † Xiaoxin Wu, † Jian Zhang, † Dongmei Li, Ridong Cong, Jing Liu, Qiliang Cui
  01/2012;
• Article: Brillouin scattering study of liquid methane under high pressures and high temperatures.

  Min Li, Fangfei Li, Wei Gao, Chunli Ma, Liyin Huang, Qiang Zhou, Qiliang Cui
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  ABSTRACT: Brillouin scattering measurements were performed on liquid methane using diamond anvil cell along five isotherms and at the pressures up to solidification points. Sound velocity, refractive index, and adiabatic bulk modulus of liquid methane as function of pressure were determined with the measurements from the platelet and backscattering geometries. The maximum pressure and temperature reached up to 5.12 GPa and 539 K. The sound velocity, refractive index, and adiabatic bulk modulus increased with pressure along each isotherm. The equation of state of liquid methane was determined from the present Brillouin results.
  The Journal of chemical physics 07/2010; 133(4):044503. · 3.09 Impact Factor