Browsing White, Mary Anne by Title
Now showing items 15-34 of 45
-
Low thermal conductivity of the negative thermal expansion material, HfMo2O8
The thermal conductivity of the cubic polymorph of hafnium molybdate, HfMo2O8, was determined over the temperature range of 2-400 K. The values of thermal conductivity were low (0.64 +/- 0.15 W m(-1) K-1 at T=300 K for a ... -
The nature of ammonium ion disorder in ammonium tetrafluoroaluminate, NH4AlF4.
To clarify previous conflicting reports concerning the existence of an order-disorder phase transition in NH4AlF4 at T ?150 K, the heat capacity of this compd. was measured from T = 15 to 305 K, by adiabatic calorimetry. ... -
Phase transitions in M(ClO4)2.6H2O (M = magnesium, zinc). Investigations by adiabatic calorimetry and infrared spectroscopy.
IR spectra of Mg(ClO4)2.6H2O at 10 K indicate a complex structure contg. at least 16 distinct types of H2O protons. At 107.9 K this structure transforms sharply to a much simpler disordered form (?Strans = 7.754 J K-1 ... -
Phase transitions in metal perchlorate hydrates: the supposed hydrate-to-pseudohydrate transformations.
A polemic. The hydrate-to-pseudohydrate transformations in metal perchlorate hydrates reported by M. B. Patel and H. D. Brist (ibid. 1983, 79, 4489) and Solid State Commun. (48, 139 (1983)) as well as the suggested ... -
The Phase-Transitions of Ferroelastic K2SeBr6 - a Calorimetric and X-Ray-Diffraction Study
No abstract available. -
Photoacoustic Investigation of the Temperature and Magnetic-Field Dependence of the Specific-Heat Capacity and Thermal-Conductivity Near the Curie-Point of Gadolinium
The photoacoustic technique was used as a simple but accurate tool to simultaneously determine the specific-heat capacity C and thermal conductivity kappa of gadolinium in the neighborhood of the Curie point. One ... -
-
Spin waves and quantum criticality in the frustrated XY pyrochlore antiferromagnet Er2Ti2O7
We report detailed measurements of the low temperature magnetic phase diagram of Er2Ti2O7. Heat capacity and time- of- flight neutron scattering studies of single crystals reveal unconventional low- energy states. Er3+ ... -
Structural principles and amorphouslike thermal conductivity of Na-doped Si clathrates
The postulated low thermal conductivity and the possibility of altering the electronic conductivity of metal-doped clathrates with semiconducting host elements have stimulated great interest in exploring these compounds ... -
Structure, thermal, and transport properties of the clathrates Sr8Zn8Ge38, Sr8Ga16Ge30, and Ba8Ga16Si30
The structural parameters, thermal properties, and transport properties of three type I clathrates, namely Sr8Zn8Ge38, Sr8Ga16Ge30, and Ba8Ga16Si30, have been determined at or below room temperature. The structural ... -
A study of phase transitions in cadmium perchlorate hexahydrate (Cd(ClO4)2.6H2O) by adiabatic calorimetry and infrared spectroscopy.
A calorimetric study of Cd(ClO4)2.6H2O from 20 to 345 K shows 3 phase transformations, at 124.8, 238.45, and 271.62 K. IR spectra indicate that the low-temp. structure (below 124.8 K) contains 1 type of [Cd(OH2)6]2+, of ... -
Technique for determination of accurate heat capacities of volatile, powdered, or air-sensitive samples using relaxation calorimetry
We introduce a four-step technique for the accurate determination of the heat capacity of volatile or air-sensitive samples using relaxation calorimetry. The samples are encapsulated in a hermetically sealed differential ... -
Temperature dependence of thermal conductivity enhancement in single-walled carbon nanotube/polystyrene composites
The thermal conductivity of single-walled carbon nanotube (SWCNT)/polystyrene composites, prepared by a method known to produce a uniform distribution of SWCNT bundles on the micrometer length scale, was measured in the ... -
Thermal and Diffraction Studies of Phase-Transitions in the Incommensurate Compound [P(Ch3)(4)]2CuCl4
Calorimetric and x-ray-diffraction studies of the commensurate