A new68Ge/68Ga generator using CeO2 as absorbent for68Ge has been developed. Sharp elution curves were obtained by using 0.02 mol/l HCl as eluent. About 56% of68Ga formed on the column was concentrated in 0.5 ml of eluate. Neither radioactive impurities, nor dissolved cerium were found in the eluate.
In this work the analysis procedures of fission gas compositions and their isotopic distributions using a gas chromatography
(GC) system and/or a quadrupole mass spectrometer (QMS) system were established, and their analysis results were reviewed
in order to evaluate their analytical performance. Also, the accumulated data, up to now, regarding fission gas measurement
were reviewed to discern any irradiation histories of the punctured fuel rods. A simple gas injection apparatus was designed
and fabricated for the quantitative injection of a small volume of fission gas into the GC and the QMS system. With an appropriate
temperature controlling of a molecular sieve 5A column, nitrogen, krypton and xenon of a mixture gas was clearly separated
within 7 min. According to the analysis results, the relative standard deviation in the determination of fission gas compositions,
krypton and xenon, by the GC analysis or by the QMS analysis was about 1%. Based on the review results of the isotopic ratios
of krypton and xenon of the released fission gas, it is likely that no abnormally irradiated rods, i.e. defected rods, were
included among the punctured rods.
Authors:Jung-Hoon Song, Min-Chul Song, Kyeong-Ho Yeon, Jung-Bae Kim, Kun-Jai Lee, and Seung-Hyeon Moon
A magnetic filter — continuous electrodeionization (CEDI) hybrid separation system was investigated for the purification of the primary coolant in a nuclear power plant. A magnetic filter system with a 3000 Gauss magnetic field and a CEDI system with a cell consisting of 3 compartments were used for the removal of magnetite and nickel ions, respectively. The hybrid separation system achieved removal rates of 98% for magnetite and 99% for the nickel ions demonstrating its feasibility for the purification of primary coolant.
Authors:Kang-Zhen Xu, Yong-Shun Chen, Min Wang, Jin-An Luo, Ji-Rong Song, Feng-Qi Zhao, and Rong-Zu Hu
A novel energetic material, 4,5-dihydroxyl-2-(dinitromethylene)-imidazolidine (DDNI), was synthesized by the reaction of FOX-7 and glyoxal in water at 70 °C. Thermal behavior of DDNI was studied with DSC and TG-DTG methods, and presents only an intense exothermic decomposition process. The apparent activation energy and pre-exponential factor of the decomposition reaction were 286.0 kJ mol−1 and 1031.16 s−1, respectively. The critical temperature of thermal explosion of DDNI is 183.78 °C. Specific heat capacity of DDNI was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is 217.76 J mol−1 K−1 at 298.15 K. The adiabatic time-to-explosion was also calculated to be a certain value between 14.54 and 16.34 s. DDNI presents lower thermal stability, for its two ortho-hydroxyl groups, and its thermal decomposition process becomes quite intense.
In order to determine whether local anesthetics directly affect the propagation and strength of myometrial contractions, we compared the effects of bupivacaine, ropivacaine, lidocaine and tetracaine on the contractions of myometrium isolated from pregnant and non-pregnant rats. Full-thickness myometrial strips were obtained from 18- to 21-day pregnant and non-pregnant Sprague-Dawley rats and incubated in an organ bath. When spontaneous contractions became regular, strips were exposed to cumulative concentrations of the four local anesthetics ranging from 0.01 to 300 μmol/L and the amplitude and frequency of contraction were recorded. All four compounds caused a concentration-dependent inhibition of the contractility of pregnant and non-pregnant uterine muscle. In pregnant myometrium, the concentration that caused 50% inhibition (IC50) was 100 μmol/L for bupivacaine, 157 μmol/L for ropivacaine, > 1000 μmol/L for lidocaine, and 26.3 μmol/L for tetracaine. In non-pregnant myometrium, the IC50 was 26.9 μmol/L for bupivacaine, 40 μmol/L for ropivacaine, 384 μmol/L for lidocaine, and 7.4 μmol/L for tetracaine. These results suggested that local anesthetics do inhibit myometrial contractions in pregnant and non-pregnant rats in a concentration-dependent manner.