System and method for regulating a power converter. The present invention may be advantageously used for obtaining spherical, uniformly micro sized toner particles through the emulsion polymerization only, without performing the aggregation or melting process. 9 wt % or higher; cutting the ingot into a cut powder and hydrogenating the cut powder into ZrH2; pulverizing and dehydrogenating the resultant product into a Zr powder and oxidizing the Zr powder at a high temperature in an oxygen atmosphere into a ZrO2 fine powder; and mixing the ZrO2 fine powder with B having a purity of 99. Ipomoea batatas Sweet Caroline Light Green is suitable for use in landscaping and containerized gardens.