We observed the acute effects of Qigong training on the levels of human endogenous opioid peptides, such as beta-endorphin, and other stress hormones [adrenocorticotrophic hormone (ACTH), cortisol, and dehydroepiandrosterone-sulfate (DHEA-S)] in a group of ChunDoSunBup Qigong trainees. At pre (-10 min), mid (40 min) and post (70 min) time of training, blood was taken for the determination of plasma level of hormones. The level of beta-endorphin was significantly increased during the mid-time of training while the level of ACTH declined at the mid- and post-time of training. Cortisol and DHEA-S were not significantly changed during training. This result suggests that Qigong training, as a stress coping method, affects and plays a role in hormonal regulation related to the maintenance of homeostasis in man.

In this study, we obtain experimental understanding of the mode characteristics of a droplet placed on a flat surface under periodic forced vibrations. The detachment conditions for the droplet on the surface were also studied. In order to estimate the resonance frequency of a droplet placed on a hydrophobic surface, theoretical modelling was combined with experimental approaches. Two high speed cameras were used to observe droplet characteristics, including mode shape, detachment, occurrence of secondary droplet breakup, and horizontal torsional motion. Two cameras were installed to the right above the droplet and at the side of the droplet. There was no more than an 18% discrepancy between the theoretical and experimental resonance frequencies. This discrepancy was likely caused by several factors such as contact line friction, nonlinear wall adhesion, and experimental uncertainty. When applying a relatively low voltage to a speaker, the contact line of a droplet was pinned and shape oscillations of the droplet appeared in a bilaterally symmetric way. In contrast, at higher voltages, the contact line depinned and the shape oscillations became more active. For excitation frequencies identical to the mode frequency, the lobe size of the droplet was relatively larger than that at neighbouring frequencies. The experimental results also indicate that the generation and complete detachment of small-scale droplets occur only at the 2nd mode.

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This study aimed to understand the mode characteristics of a droplet subject to periodic forced vibration and the detachment of a droplet placed on a plate surface. An surface was coated with Teflon to clearly observe the behavior of a droplet. The contact angle between the droplet and surface and the hysteresis were found to be approximately 115° and within 25°, respectively. The coating process was performed in a clean room that had an environment with a low level of contaminants and impurities such as air dust, detergents, and particles. To predict the resonance frequency of a droplet, theoretical and experimental approaches were applied. Two high-speed cameras were configured to acquire side and top views and thus capture different characteristics of a droplet: the mode shape, the detachment, the separated secondary droplet, and the waggling motion. A comparison of the theoretical and experimental results shows no more than 18 discrepancies when predicting the resonance frequency. These differences seem to be caused by contact line friction, nonlinear wall adhesion, and the uncertainty of the experiment. For lower energy inputs, the contact line of the droplet was pinned and the oscillation pattern was axisymmetric. However, the contact line of the droplet was de-pinned as the oscillation became more vigorous with increased energy input. The size of each lobe at the resonance frequency is somewhat larger than that at the neighboring frequency. A droplet in mode 2, one of the primary mode frequencies, exhibits vertical periodic movement as well as detachment and secondary ejection from the main droplet.Corresponding