The desorption behavior of Tc from active carbon was studied as a fundamental study on separating Tc from high-level radioactive liquid waste. Technetium adsorbed from 0.5 M HNO, solution could be ...desorbed more effectively with alkaline thiocyanate solution than with HN0
3
. The adsorption behavior of Tc on the active carbon previously treated with alkaline thiocyanate solution was also studied for the purpose of a recycle use of the active carbon.
The distribution coefficient of Tc, Kd, depended sensitively on pH in the presence of KSCN. The value of Kd exceeded 10
5
ml/g below pH 2 and became less than 10 ml/g above pH 4. It was found by spectrophotometric analysis that this large difference in Kd was due to the change of the chemical form of Tc. Below pH 2, Tc was adsorbed in the form of thiocyanate complexes, TC(NCS)
6
2-
and Tc(NCS)
6
3-
. Above pH 4, these complexes were hardly formed and TcO
4
−
was desorbed by anion exchange reaction with thiocyanate ion.
Leadframes with heat spreaders have been developed for mounting high power LSI devices, such as MPUs and MPEGs. Power dissipation of this package is from 2 to 3 W. However, there is a great need for ...less expensive leadframes for Heatspreader-enhanced Quad Flat Packs (HQFPs) for general use. Therefore, we modified the structure of the leadframe for the HQFP and improved the manufacturing to achieve very low-cost leadframes. The features of this new leadframe are as follows: (1) Nearly the same cost as a conventional leadframe with-out a heat spreader. (2) From 2 to 3 W thermal dissipation. (3) Easy wire bonding. (4) High reliability through solder reflow. This leadframe achieves high thermal performance and guarantees high reliability at the least cost.
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