• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.123-128
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• 2018

Effect of activators in flux on the printability and wettability of a solder paste was evaluated in this study. The activators in this study were dicarboxylic acids, which were oxalic acid (n = 0), malonic acid (n = 1), succinic acid (n = 2), glutaric acid (n = 3), adipic acid (n = 4), and pimelic acid (n = 5). When the solder pastes were observed with a SMT scope, solder with glutaric acid showed clean and shiny surface when it was melted. Slump ratio of the solder pastes was low when the carbon numbers of the dicarboxylic acid were 1-3. Spreadability was high when the carbon number was over 2. Zero cross time of wetting balance test was under 1 sec when the carbon number was over 3. When activator was oxalic acid or malonic acid, zero cross time was over 1 sec and maximum wetting force was low. Fluxes with the oxalic acid and malonic acid showed decomposition at the temperature close to melting point. Among the dicarboxylic acids, glutaric acid provided excellent slump, spreadability, and wettability.

• Korean Journal of Acupuncture
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• v.29 no.2
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• pp.188-199
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• 2012

Objectives : This study was performed to find the desirable remaining time of needle in the acupuncture treatment. Methods : The 21 volunteers were given acupuncture at LU9 vertically and needles were remained for 2 min, 10 min, 15 min, 30 min, respectively. The thermographic change induced by acupuncture was measured with Digital Infrared Thermographic Image at the following acupoints: LU11, LU10, LU9, LU8, LU5, LU1, and PC7. The statistical significance of thermographic change was evaluated using paired t-test and post hoc Wilcoxon test. Results : The most significant changes after acupuncture were produced when needles were remained for 10 min or 15 min. LU11, LU5, LU1, and PC7 were the point at which all of the remaining time produced significant change commonly. At LU11, the biggest change was produced when needle was remained for 15 min, while at LU5, LU1, and PC7, the biggest change was produced when needle was remained for 30 min, and the smallest change was produced when needle was remained for 10 min at all of acupoints of LU11, LU5, LU1, and PC7. The unbalance between left side and right was decreased the most largely in 15 min group. Conclusions : The results of this study suggest that the desirable remaining time of acupuncture needle might be 15 min.