• Biomedical Science Letters
• /
• v.15 no.1
• /
• pp.87-91
• /
• 2009

In photodynamic therapy (PDT), oxygen plays important role. Because of singlet oxygen which is produced by activated photosensitizer after laser irradiation of specific wavelength. The aim of this study is to find how oxygen concentration affects anticancer effect in PDT. Groups were divided into PDT with oxygen applied group and only PDT applied group. PDT with oxygen applied group supplied oxygen for 15 minute before laser irradiation. In vitro, CT-26 cell was incubated with various concentration of photofrin $(50.0{\sim}0.05{\mu}g/ml)$ and was irradiated with 632nm diode laser 6hr after application of photofrin. The cell viability of two groups was assessed by MTT assay. In vivo, CT-26 cell line was transplanted into the subcutaneous tissue of BALB/c mouse. The anticancer effect of two groups was measured by tumor volume change. In vitro study, the cell viability was significantly decreased at $1.56{\sim}3.13{\mu}g/ml$ in PDT with oxygen applied group. In vivo study, the PDT with oxygen applied group significantly higher reduction rate of tumor volume 7 days after PDT compared to PDT only group. The high oxygen concentration might enhance the anticancer effect of the photodynamic therapy.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.25 no.1
• /
• pp.31-35
• /
• 2014

Objectives : The aim of this study was to evaluate the effectiveness and feasibility of coblation resection for the treatment of laryngotracheal disease. Methods : We conducted a retrospective review, evaluating 7 patients with laryngotracheal disease treated using coblator. Information collected included demographic data of the patients, diagnosis, size and location of the disease, procedure time, the number of previous operation, and the postoperative complication. Results : Among the etiology, granulation is most frequent (n=4), followed by recurrent repiratory papillomatosis (n=2) and tracheal stenosis (n=1). The location of lesions was peristomal area (n=2), glottis (n=2), subglottis (n=2) and mid-trachea. Coblation resection could remove the lesions completely and there was no significant complication including local burn, bleeding, and hypertrophic scar. The procedure time was shorter than the previous operation using $CO_2$ laser. Conclusion : Coblation resection is an effective and safe method for layngotracheal disease and can substitute the classic method such as $CO_2$ laser.

• Korean Journal of Bronchoesophagology
• /
• v.4 no.1
• /
• pp.91-95
• /
• 1998

Background： Laryngeal cancer, the most common malignancy of head and neck, is being detected and treated in earlier and more effectively due to introduction of endoscope, continuous development of radiographic technology, and advancement in new surgical techniques such as laser surgery and conservation laryngeal surgery Objectives To compare the different treatment results for early laryngeal cancer to determine which methos provides the good prognosis. Materials and Methods： Retrospective study was done for 135 patients with early laryngeal squamous cell carcinoma(Stage I or II) who were treated at our institute between 1989 to 1996. There were 105 patients with glottic cancer(Stage I: 68 patients, Stage II：37 Patients) and 30 patients with supraglottic cancer(Stage I: 12 patients, Stage II：18 patients) Initial treatment included radiation therapy for 54 patients, endoscopic laser surgery for 8 patients, laryngofissure and cordectomy for 8 patients, vertical partial laryngectomy for 37 patients, supraglottic laryngecomy for 14 patients and supracricoid laryngectomy for 5 patiens, and total laryngectomy for 9 patients. Results : Salvage treatments, such as total laryngectomy, conservation laryngeal surgery, radiation therapy and neck dissection were performed for initial treatment failure with 9 patients after radiation therapy, 8 patients after conservation laryngeal surgery, 2 patients after endoscopic laser and 3 patients after total laryngectomy. Overall 3-year survival rate for glottic 71 was 92.4%, glottic f 84.3%, supraglottic 7172.7%, and supraglottic f was 63.%%. However, survival rate of the same stage was variable according to the choice of initial treatment. Conclusion New classification of the early laryngeal cancer was necessary and helpful for the choice of the initial treatment.

• Korean Journal of Optics and Photonics
• /
• v.10 no.5
• /
• pp.364-368
• /
• 1999

We investigate the evaluation items of LSU (Laser Scanning Unit), such as beam size, f$\theta$ characteristics, linearity, skew and bow, optical power ratio between image height of 0mm and $\pm$108 mm, pitch error, Jitter and shift of printing position. Through the measurement of LSU using BSH (Beam Scan Head) installed on LMC (Linear Motion Controller) which moves linearly within the whole scanning range (-108 mm~+108 mm), we can ascertain plastic f$\theta$ lenses, which are manufactured by TVLP (Two-step Variable Low Pressure) molding method, to satisfy 600DPI(Dots Per Inch) performance.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.1
• /
• pp.108-113
• /
• 2010

Decreasing products lifecycles and increasing consumers desires for quality and design make the automotive industries try to reduce time for developing new designs. In order to reduce developing time, I have designed head lamps, which are really important to have an effect on brand identities and images, using layers concept that is one of the international automotive design trends by alias and photoshop, and produced prototype by RP. To assemble the produced prototype to the body and manufacture the frame to exterior modelling efficiently, I have studied on joining dissimilar materials of aluminum alloy that can make the prototype lighter and stainless steel, which is good for corrosion resistance by using laser beam. These materials were welded for finding the optimum joining condition and evaluating the soundness of joining zone. The joining was performed under the condition of laser power 500, 550, 575, 600W and 11~14Hz. In this study, the suitable joining condition between aluminum alloy (Al 2024) and stainless steel (STS 304) can be obtained at the laser power 575W and frequency 12Hz.

• 대한미세수술학회:학술대회논문집
• /
• 1995.11a
• /
• pp.72.1-72.1
• /
• 1995

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.118.4-118
• /
• 2001

An Inspection system, composed of sensor head and controller, is presented which is a 3-D laser vision system using principles of optical triangulation for weld quality and chamfer quality. The sensor head id composed of laser diode, micro CCD camera, filter and several optical components. This systems can be used in welding bead and undercut inspection and chamfer quality inspection as well. It is mech more convenient to use and the inspection time is to be greatly shortened compared with conventional inspection method. Furthermore, data saved in controller can be used for statistics afterwards. This system has been begin used in Koje Shipyard of Samsung Heavy Industries and the need is being increased.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.06a
• /
• pp.24-33
• /
• 2000

The effect of particulate contamination on friction and wear between a negative-pressure picoslider / tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data zone were better for those of the laser-textured zone. It was also found that durability of head-disk interface (HDI)decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• Tribology and Lubricants
• /
• v.16 no.6
• /
• pp.469-476
• /
• 2000

The effect of particulate contamination on the friction and wear between a negative-pressure picoslider/tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data Bone were better than those in the laser-textured zone. It was also found that durability of head-disk interface (HDI) decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.160-163
• /
• 2002

Silica waveguide for an integrated diffractive optical head system was designed and fabricated. The waveguide was designed to optimize the optical efficiency of red and/or blue laser source, and a lab-made RF magnetron sputter was adopted to deposit silica cladding and core layers on SiO$_2$/Si substrates. The cladding and core layers were formed using commercial targets, and the former was done with ＃7740 and the latter with BK7 and BAK4, respectively The surface roughness of the waveguide layers was measured to be 30.3${\AA}$ for BK7 and 17.8${\AA}$ for BAK4, and the difference of refractive indices between core and cladding layers was 0.9% and 2.5%, respectively. The waveguide fabricated with the core layer of BK7 showed better optical properties when the final diffractive optical probe heads were measured with red laser(650nm) source.