• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.06a
• /
• pp.339-343
• /
• 2005

Laser material processing is a very fast growing technology for various industrial applications, because of many advantages. Its major advantage of less and controlled heat input has been exploited successfully for the very critical application of aluminium alloy welding. This study suggested the occurrence source of weld-defects and its solution methods in a welding of lithium ion battery by pulsed Nd:YAG laser. In experiment, battery case has changed over joint geometry from welding of side position to flat one. In case of a electrolyte injection hole in order to seal it, welding is carried out after pressing Al ball. At this time, an eccentric degree, contact length and gap are worked as a major parameters. As improving the method of Al ball pressing, it was able to reduce an eccentricity, increase the contact length and decrease gap. As a results of a experiment, a sound weld bead shape and crack-free weld bead can be obtained.

• The Korean Journal of Pain
• /
• v.20 no.2
• /
• pp.195-198
• /
• 2007

A cluster headache is characterized by the occurrence of strictly unilateral and periocular pain with no side shift and ipsilateral oculofacial autonomic symptoms such as conjunctival injection, lacrimation, rhinorrhea and miosis. Cluster headache involves the activation of parasympathetic nerve structures located within the sphenopalatine ganglion, and blockade of the sphenopalatine ganglion has been shown to be effective at the treatment of cluster headaches that are resistant to conventional therapy. Herein, we describe a case of a 50-year-old male with a cluster headache that could not be controlled by conventional treatments who showed improvement after being treated with sphenopalatine ganglion pulsed radiofrequency.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.6
• /
• pp.38-47
• /
• 2008

The liquid column and spray trajectory have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle were varied to provide of jet operation conditions. The Pulsed Shadowgraph Photography and Planar Liquid Laser Induced Fluorescence technique was used to determine the injection characteristics in a subsonic crossflow of air. And the mainly objectives of this research was to get a empirical formula of liquid column and spray region trajectory with forward and reversed injection of air stream. As the result, This research has been shown that each trajectories were spatially dependent on air-stream velocity, fuel injection velocity, various injection angle, and normalized injector exit diameter. Furthermore, the empirical formula of liquid column trajectories has been some different of drag coefficient results between forward and reversed angled injection.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1910-1912
• /
• 1996

This paper presents the results of laboratory experimentals to remove $SO_2$ and $NO_x$ by a pulsed corona discharge in the wire-plate reactor. A rotating spark gap switch was used to generate the pulse by chewing the dc high voltage. Repetition frequency of the pulse was 60Hz and rising time of 50ns. The photo pictures of positive streamer corona taken by ICCD camera, pulse voltage and current were measured using a digital oscilloscope. Simultaneous effects of $C_{2}H_{4}$ injection and heterogeneous chemical reactions on nonthermal plasma process to remove $SO_2$ and $NO_x$ from flue gas were investigated in the present study

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.1
• /
• pp.42-49
• /
• 1992

Charge accumulation characteristics in low density polyethylene (LDPE) has been discussed based upon the internal charge distrubution measured by the pulsed electroacoustic technique. When the negative voltage with respect to earth is applied to the upper electrode, the negative charges near the anode and the positive charges near the cathode are accumulated in LDPE. Also, there was an asymmetric behavior of charge accumulation exhibiting that the charge accumulation near the anode keeps increasing whereas that near the cathode increases first and then decreases. Besides, under the present test conditions the internal charge distrubution becomes stabilized eventually. When the positive voltage with respect to earth is applied to the upper electrode, on the other hand, no such asymmetric charge accumulation was found. Therefore, it can be concluded that the heterocharges are accumulated at the surface region of LDPE subjected to high do voltages and that the begavior of charge accumulation depends on the polarity of do voltage and the position of charge accumulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.2
• /
• pp.166-174
• /
• 2009

The liquid column trajectory and column breakup length characteristics have been experimentally studied in angled jets injected into subsonic crossflow. Pulsed shadowgraph photography and Planar Liquid Laser Induced Fluorescence measurements were used to determine the angled effects. And the main objectives of this research are to get a empirical formula of liquid column trajectory and breakup length with below the $90^{\circ}$ degree injection angle conditions, and were compared with previous results. It was also found that the empirical formula, which reversed injection conditions of air stream. As the result, This has been shown that liquid column trajectories and column breakup length were spatially dependent on various injection angle, normalized injector exit diameter, air-stream and fuel injection velocity. Furthermore, the empirical formula of liquid column trajectories and breakup length has been some different of drag coefficient results between normal angled injection and reversed injection in subsonic crossflow.

• Journal of Korean Physical Therapy Science
• /
• v.11 no.3
• /
• pp.5-13
• /
• 2004

The use of therapeutic ultrasound(US) in humans with malignant neoplasms has been contra-indicated in physical therapy practice. Some studies have shown the results after application of US inhibited of tumor growth but some studies have shown the results facilitated of tumor growth in mouse. The purpose of this study were to determine the effects of US on rectal sarcoma(CT-26) in mouse and to determine the histological change of tumor. Thirty-five female BALB/C mouse, age 6 to 8 weeks received subcutaneous injection of 0.1 105 tumor cells. When tumors grew to 5 mm in diameters, the mouse were randomly assigned to control group(n=7) and high powered continuous US group(n=7) and low powered continuous US group(n=7) and high powered pulsed US group(n=7) and low powered pulsed US group(n=7). The experimental group (four groups) received 10 treatments over a 10-day period of 3 MHz ultrasound. Tumor dimension were measured on days 1(start of treatment), 5(midtreatment), and 10(end of treatment, preexcision and postexcision). Tumors were weighed after excision and the mouse were observated histological change of tumor. All tumors grew larger over time. Mean tumor weights(in grams) and volumes(in cubic millimeters) were 2.063 g and $2729.313\;mm^3$ for the high powered continuous US group 1.881 g and $2428.002\;mm^3$ for the low powered continuous US group 1.730 g and $2381.002\;mm^3$ for the high powered pulsed US 1.673 g and $2289.562\;mm^3$ for the low powered pulsed US group 1.670 g and $2297.333\;mm^3$ for the control group. Ultrasound increased the weight and volume of subcutaneous tumor in mouse. We urge caution in the use of ultrasound in the areas of tumors.

• Journal of the Optical Society of Korea
• /
• v.13 no.1
• /
• pp.65-74
• /
• 2009

Device quality indium tin oxide (ITO) films are deposited on glass substrates and ultra-thin diamond-like carbon films are deposited as a buffer layer on ITO by a pulsed Nd:YAG laser at 355 nm and 532 nm wavelength. ITO films deposited at room temperature are largely amorphous although their optical transmittances in the visible range are > 90%. The resistivity of their amorphous ITO films is too high to enable an efficient organic light-emitting device (OLED), in contrast to that deposited by a KrF laser. Substrate heating at $200^{\circ}C$ with laser wavelength of 355 nm, the ITO film resistivity decreases by almost an order of magnitude to $2{\times}10^{-4}\;{\Omega}\;cm$ while its optical transmittance is maintained at > 90%. The thermally induced crystallization of ITO has a preferred <111> directional orientation texture which largely accounts for the lowering of film resistivity. The background gas and deposition distance, that between the ITO target and the glass substrate, influence the thin-film microstructures. The optical and electrical properties are compared to published results using other nanosecond lasers and other fluence, as well as the use of ultra fast lasers. Molecularly doped, single-layer OLEDs of ITO/(PVK+TPD+$Alq_3$)/Al which are fabricated using pulsed-laser deposited ITO samples are compared to those fabricated using the commercial ITO. Effects such as surface texture and roughness of ITO and the insertion of DLC as a buffer layer into ITO/DLC/(PVK+TPD+$Alq_3$)/Al devices are investigated. The effects of DLC-on-ITO on OLED improvement such as better turn-on voltage and brightness are explained by a possible reduction of energy barrier to the hole injection from ITO into the light-emitting layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.84-87
• /
• 2001

Space charge formation at high temperature was investigated in several polymers using pulsed electro-acoustic (PEA) method. In SXLPE, homocharge is found and increased as an increase of temperature. In a charge of polarity of poling voltage(positive to negative), space charge mainly cause of hole injection. In Ionomer, heterocharge is found because of ion. As an increase of temperature heterocharge is also increased. In PET, As an increase of temperature homocharge is decreased.

• Proceedings of the Optical Society of Korea Conference
• /
• 2001.02a
• /
• pp.104-105
• /
• 2001

Recently, plasma injection has been suggested as a means to enhance and control combustion rates of propellant materials. It is also of interest for applications in fields such as rocket propulsion, electrothermal-chemical (ETC) launchers, and hypersonic mass acceleration technology. In order to characterize the plasma fundamental measurements such as the plasma excitation temperature and electron number density are essential. (omitted)