Studies on Production of Supercooling State and Electrical Properties of Water Condenser for Energy Compression

由于水具有较高的介电常数，因此被用作脉冲功率技术中脉冲形成线的介质材料。介电常数随温度的降低而增加。到目前为止，对水的电气特性所做的大部分工作都限制在0^ C以上的温度范围内。这样做的目的是使过冷却水稳定，并了解它的电学性质。同时采用水膨胀交联聚丙烯酸（PAA）凝胶。主要结果总结如下：1)水的冷冻温度为-15^ C， PAA的冷冻温度为-12^ C。这个温度取决于蓄水材料的表面张力，以及电场和磁场的存在。2)水的介电常数随温度的降低而增大，其特性与温度高于零时相似。3) PAA凝胶所含的水分是凝胶体积的5倍左右。然而，电导率却比水高了3个数量级。4) PAA凝胶的膨胀和收缩行为可由溶剂的pH值和电场强度控制。为了使过冷水和-PAA凝胶应用于介电材料，需要进一步研究击穿场强、击穿冲击对过冷行为的影响等问题，并开发消除低聚物的技术。

Water has been taken as a dielectric material of pulse forming lines for pulse-power technology because of its high dielectric constant. The dielectric constant increases with decreasing temperature. Most of the work done on electrical characteristics of water so far is limited in temperature range above 0^ﾟC. The purpose of this is to make supercooling water stable, and to know the electrical properties of it. Water-swollen cross-linked poly-acrylic-acid (PAA) gels were taken as well. The main results summarized follows.1) The frozen temperature was around -15^ﾟC for the water and -12^ﾟC for the PAA. This temperature depended on the surface tension of materials which holds water, and the presence of electric and magnetic fields.2) The dielectric constant of the water increased with decreasing temperature in a similar characteristic as that in temperatures above zero.3) The PAA gel contained water around 5 times as large as the gel volume itself. However, the conductivity became about 3 orders of magnitude higher than that of the water.4) The swelling and contraction behavior of the PAA gel could be controlled by the pH values of the solvent and the electric field strength.In order to develop supercooling-water and -PAA gel to the dielectric materials, the breakdown field strength, influence of shock of breakdown on the supercooled behaviors, etc. and development of technology to eliminate oligomers should be investigated further.