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Abstract  

To provide a convenient and facile method to evaluate the radiochemical purity (RCP) of 99mTc-TRODAT-1 in quality control of routine clinical application, a simplified method of single-strip thin layer chromatography (TLC) was developed and validated by high performance liquid chromatography (HPLC). The RCP data of TLC correlated well with HPLC.

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Abstract  

During the past decade, interest has increased in qualifying and quantifying the threat posed to the public by the illegal use of radionuclides. In order to take investigations beyond the laboratory bench into more realistic scenarios, environmental and safety considerations dictate that these studies be performed on stable and benign surrogates. This paper discusses some of these studies, specifically the use of cerium dioxide for actinide ceramics and calcium and natural strontium ceramics for those based on 90Sr.

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Thermodynamic investigation of room temperature ionic liquid

The heat capacity and thermodynamic functions of BMIPF6

Journal of Thermal Analysis and Calorimetry
Authors: Z. Zhang, T. Cui, J. Zhang, H. Xiong, G. Li, L. Sun, F. Xu, Z. Cao, F. Li, and J. Zhao

Abstract  

The molar heat capacities of the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluoroborate (BMIPF6) were measured by an adiabatic calorimeter in temperature range from 80 to 390 K. The dependence of the molar heat capacity on temperature is given as a function of the reduced temperature (X) by polynomial equations, C P,m (J K−1 mol−1) = 204.75 + 81.421X − 23.828 X 2 + 12.044X 3 + 2.5442X 4 [X = (T − 132.5)/52.5] for the solid phase (80–185 K), C P,m (J K−1 mol−1) = 368.99 + 2.4199X + 1.0027X 2 + 0.43395X 3 [X = (T − 230)/35] for the glass state (195 − 265 K), and C P,m (J K−1 mol−1) = 415.01 + 21.992X − 0.24656X 2 + 0.57770X 3 [X = (T − 337.5)/52.5] for the liquid phase (285–390 K), respectively. According to the polynomial equations and thermodynamic relationship, the values of thermodynamic function of the BMIPF6 relative to 298.15 K were calculated in temperature range from 80 to 390 K with an interval of 5 K. The glass transition of BMIPF6 was measured to be 190.41 K, the enthalpy and entropy of the glass transition were determined to be ΔH g = 2.853 kJ mol−1 and ΔS g = 14.98 J K−1 mol−1, respectively. The results showed that the milting point of the BMIPF6 is 281.83 K, the enthalpy and entropy of phase transition were calculated to be ΔH m = 20.67 kJ mol−1 and ΔS m = 73.34 J K−1 mol−1.

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Abstract  

Positron annihilation lifetime (PAL) experiments are performed in polycarbonate (PC) exposed to CO2 and He gases as a function of time and pressure. In PC/CO2 systems, hole size and fraction reduced from PAL data increase as a function of CO2 pressure and exposure time. Significant hysteresis in positron lifetime data is observed during CO2 abasorption/desorption. In PC/He systems, no variation is observed. Hole size distribution in the CO2-exposed polymers is found to be significantly broader than in unexposed samples. The high sensitivity of PAL results to CO2 exposure of PC is thought to relate to the microstructural changes in the polymer matrix, such as penetrant plasticization, gas hydrostatic pressure effect, and molecular filling and creation of holes.

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