• Applied Science and Convergence Technology
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• v.26 no.4
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• pp.79-85
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• 2017

The crack-free AlGaN template has been successfully grown by using selective area growth with triangular GaN facet. The triangular GaN stripe structure was obtained by vertical growth rate enhanced mode with low growth temperature of $950^{\circ}C$ and high growth pressure of 500 torr. The lateral growth rate enhanced mode of AlGaN for crack-free and flat surface was also investigated. Low pressure of 30 torr and high V/III ratio of 4400 were favorable for lateral growth of AlGaN. It was confirmed that the $4{\mu}m$ -thick $Al_{0.2}Ga_{0.8}N$ was crack-free over entire 2-inch wafer. The dislocation density of $Al_{0.2}Ga_{0.8}N$ was as low as ${\sim}7.6{\times}10^8/cm^2$ measured by cathodoluminescence. Based on the high quality AlGaN with low dislocation density, the ultraviolet laser diode epitaxy with cladding, waveguide and GaN/AlGaN multiple quantum well (MQW) was grown by metalorganic chemical vapor deposition. The stimulated emission at 349 nm with full width at half maximum of 1.8 nm from the MQW was observed through optical pumping experiment with 193 nm KrF laser. We also have fabricated the deep ridge type ultraviolet laser diode (UV-LD) with $5{\mu}m-wide$ and $700{\mu}m-long$ cavity for electrical properties. The turn on voltage was below 5 V and the resistance was ${\sim}55{\Omega}$ at applied voltage of 10 V. The amplified spontaneous emission spectrum of UV-LD was also observed from pulsed current injection.

• Korean Journal of Acupuncture
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• v.29 no.1
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• pp.17-22
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• 2012

Objectives : The purpose of this study is to discuss the diagnostic classification of the traditional medicine for pilosis, and the hair removal treatments in traditional medicine and its clinical application. Backgrounds : In recent years, appearance and beauty have become main interest that have positioned in the medical area. In clinical Korean medicine, a variety of methods such as moxibustion, superficial bleeding, multiple microneedling, facial meridian massage, herbal medicine facial pack, laser acupuncture, and intense pulsed light (IPL) have been applied. Methods and Results : Pilosis, a condition of abnormal hair growth, is stated for the first time in the publication, [Pathogenesis and Manifestations of All Diseases] by Chao Yuan-fang in 610 A.D. It shows that pilosis has been recognised as a disease for ages in Asia. Reviewing several publications, we found multiple approaches to pilosis were already existed in korean medicine. They include internal medicinal classification and its' medications. Acupuncture treatments also focused on regulation of radical causes and superficial removal of abnormal hairs. Specific treatments includes body and ear acupuncture, ear acupressure, hypodermic acupuncture, hypodermic acupuncture injection, laser acupuncture treatment. Physical and chemical methods of hair removal were widely invented. we resulted that significant scientific approaches to pilosis are under way in the korean medical field, and found a variety of medical treatments such as herbal medicines and dermatological methods. Conclusions : Hair removal treatments for pilosis in traditional medicine has a long history. Combined with advanced modern technology it can achieve greater advance in cosmetology.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.2
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• pp.1-8
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• 2009

Present studies of these experiments was conducted to using water, over a range of cross-flow velocities from 42 to 136 m/s, with injection frequencies from 35.7 to 166.2 Hz. In cross-flow field, main parameters of liquid jet for secondary breakup were cross-flow drag rather than pressure pulse frequency. As oscillation of the periodic pressure, liquid jet was moved up and down. Also, a bulk of liquid jet puff was detected at upper field of liquid surface. Because of pressure pulsation frequency, an inclination of SMD for the structured layer was evanescent. Cross-sectional characteristics of SMD at downstream area were non-structured distributions. The tendency of volume flux value for various frequency of pressure pulse was same distribution. And volume flux was decreased when the frequency of pressure pulse increasing.

• Analytical Science and Technology
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• v.18 no.1
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• pp.66-73
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• 2005

In this study, we investigated the gas chromatography (GC) and pulsed flame photometric detection (PFPD) system for the analysis of four major reduced S compounds including hydrogen sulfide ($H_2S$); methyl mercaptan ($CH_3SH$); dimethyl sulfide (DMS); and dimethyl disulfide (DMDS) contained in environmental samples. To analyze these compounds in high concentration range (above ppb level), we developed a high mode analytical setting with the loop-injection system. By contrast, we also established a low mode setting for the analysis of low concentration samples (ppt-level samples from ambient air) by the combination with thermal desorption unit (TDU). Comparative analysis of both settings revealed that relative detection properties of four S compounds are systematic enough. The results of high mode analysis indicated that the patterns were systematic among S compounds: $H_2S$ exhibited the lowest sensitivity, while DMDS showed the strongest one. The results were also compared in terms of sensitivity reductions for all compounds by dividing slope ratios between low and high mode system. Although low mode system exhibited significant reductions on the order of a few tens times, their detection characteristics were highly consistent as it was shown in the high mode setting. To learn more about absolute and relative relations between two different modes of S analysis, future studies may have to be directed to cover more complicated nature of GC/PFPD performance.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.180-180
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• 2012

Heteroepitaxial GaN nano- and micro-rods (NMRs) are one of the most promising structures for high performance optoelectronic devices such as light emitting diodes, lasers, solar cells integrated with Si-based electric circuits due to their low dislocation density and high surface to volume ratio. However, heteroepitaxial GaN NMRs growth using a metal-organic vapor phase epitaxy (MOVPE) machine is not easy due to their long surface diffusion length at high growth temperature of MOVPE above $1000^{\circ}C$. Recently some research groups reported the fabrication of the heteroepitaxial GaN NMRs by using MOVPE with vapor-liquid-solid (VLS) technique assisted by metal catalyst. However, in the case of the VLS technique, metal catalysts may act as impurities, and the GaN NMRs produced in this mathod have poor directionallity. We have successfully grown the vertically well aligned GaN NMRs on Si (111) substrate by means of self-catalystic growth methods with pulsed-flow injection of precursors. To grow the GaN NMRs with high aspect ratio, we veried the growth conditions such as the growth temperature, reactor pressure, and V/III molar ratio. We confirmed that the surface morphology of GaN was strongly influenced by the surface diffusion of Ga and N adatoms related to the surrounding environment during growth, and we carried out theoretical studies about the relation between the reactor pressure and the growth rate of GaN NMRs. From these results, we successfully explained the growth mechanism of catalyst-free and mask-free heteroepitaxial GaN NMRs on Si (111) substrates. Detailed experimental results will be discussed.

• The Korea Journal of Herbology
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• v.22 no.4
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• pp.261-270
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• 2007

Objective : The 5-HMF was not index material suitable to do the quality control of Rehmanniae Radix Preparata. In this study, We estimated the changes of oligosaccharide contents in Rehmanniae Radix Preparata using high-performance anion-exchange chromatography with pulsed amperometric detection(HPAEC-PAD). Methods : The analysis of oligosaccharide was conducted by HPAEC-PAD with Carbopac PA1, $250{\times}4mm$, 5um, and Carbopac PA1 guard column. Column temperature was kept at $30^{\circ}C$. Elution was carried out at 1000 ${\mu}l/min$ with 70mM NaOH and the injection volume was $10{\mu}l$. Each component was detected by PAD. Results : Nine constituents were found from merchandising Rehmanniae Radix Preparata(MR), while seven constituents were found in various processed Rehmanniae Radix Preparata. Not all constituents were defined but stachyose and raffinose were found in all cases. And The most common constituents of Rehmanniae radix was stachyose. In the course of processing, most of stachyose and raffinose were decreased. Stachyose was decreased slowly in the course of processing with rice wine(RR), amomi and rice wine(AR), and crataegi and rice wine(CR). However stachyose was decreased rapidly in the course of processing with fresh rehmannia juice(FR). The method with crataegi and rice wine(CR) showed the smallest decrease of stachyose. And processing method with crataegi and rice wine(CR) showed the most abundant amount for stachyose after the nineth processing. Conclusion : The changes of oligosaccharides in the course of processing were a very important direct barometers to do the quality control and set up a standard of Rehmanniae Radix Preparata.

• Parasites, Hosts and Diseases
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• v.30 no.4
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• pp.283-288
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• 1992

To observe the transmission patterns of karyotype of Pneumocystis carinii (Pc) by rat colonies, three strains of rats, Sprague-Dawlcy(SD), Wistar(W) and Fisher (F) from various animal vendors, were suppressed of their immunity by injection of methyl prednisolone. They were kept for 5 to 13 weeks in 3 different animal rooms, A, B, and C. The purified organisms were prepared in low melting point agarose gel by embedded Iysis method for pulsed field gel electrophoresis. Field inversion gel electrophoresis showed 2 patterns of the kart·otype of Pc. The rooms A and C contained SD rats from the source p, and also the room A was used for F and W rats. However, Pc from all of the SD and F rats in the room A showed same karyotypes, the pattern I. The SD rats from difFerent vendors, M and 5, were reared in the room B, and shared the same Pc karyotypes, the pattern II . The rats of W strain were from the vendor M, and immune-suppressed in the animal room A. Five weeks after the expe- riment, the Pc showed the karyotype pattern II but the pattern became mixed with the type I after 7 to 8 weeks. The Bindings revealed that the animals born and reared in the same animal quarter harbored Pc with same karyotypes. If the animals were kept under immune-suppression in the same room with heavily infected hosts, they could be infected by Pc from their neighbors. The present experimental findings suggest that Pc is transmitted among rats through the air.

• IMMUNE NETWORK
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• v.6 no.3
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• pp.154-162
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• 2006

Background: Dendritic cell (DC)-based cancer immunotherapy is studied for several years. However, it is mainly derived from autologous PBMC or leukapheresis from patient, which has limitations about yield and ability of DC production according to individual status. In order to solve these problems, inquiries about allogeneic DCs are performed but there are no preclinical trial answers for effect or toxicity of allogeneic DC to use for clinical trial. In this study, we compared the anti-tumor effect of allogeneic and autologous DCs from mouse bone marrow stem cells in mouse metastatic melanoma model. Methods: B16F10 melanoma cells ($5{\times}10^4$/mouse) were injected intravenously into the C57BL/6 mouse. Therapeutic DCs were differentiated from autologous (C57BL/6: CDC) or allogeneic (B6C3F1: BDC) bone marrow stem cells with GM-CSF, SCF and IL-4 for 13days and pulsed with B16F10 tumor cell lysate (Blys) for 18hrs. DC intra-peritoneal injections began on the 8th day after the tumor cell injection by twice with one week interval. Results: Anti-tumor response was observed by DC treatment without any toxicity especially in allogeneic DC treated mice (tumor burden score: $2.667{\pm}0.184,\;2.500{\pm}0.463,\;2.000{\pm}0.286,\;1.500{\pm}0.286,\;1.667 {\pm}0.297$ for saline, CDC/unpulsed-DC: U-DC, CDC/Blys-DC, BDC/U-DC and BDC/Blys-DC, respectively). IFN-${\gamma}$ secretion was significantly increased in allogeneic DC group stimulated with B16F10 cell lysate ($2,643.3{\pm}5,89.7,\;8,561.5{\pm}2,204.9.\;6,901.2{\pm}141.1pg/1{\times}10^6$ cells for saline, BDC/U-DC and BDC/Blys-DC, respectively) with increased NK cell activity. Conclusion: Conclusively, promising data was obtained that allogeneic DC can be used for DC-based cancer immunotherapy.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.334-340
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• 2003

For the study of the hemodynamic changes of the cranial pancreaticoduodenal arterial flow(cPDAF) in the dog with acute pancreatitis, acute pancreatitis was experimentally induced in 10 dogs by the injection of oleic acid into the accessory pancreatic duct. The parameters of cPDAF were measured by transcutaneous pulsed-wave Doppler ultrasonography. The hemodynamic changes included resistive indexe(RI), pulsatility index(PI) and maximum velocity (Vmax). Ultrasonographic scans were performed before the induction of pancreatitis and once daily for five days after the induction. The RI, PI and Vmax were increased with day as follows; the RI prior to induction was 0.625$\pm$0.096 (mean$\pm$SD), the PI was 1.117$\pm$0.289 and the Vmax was 0.349$\pm$0.094 m/s. After five days, the RI was 0.727$\pm$0.051 (p<0.0l), the PI was 1.480$\pm$0.284 (p<0.0l) and the Vmax was 0.585:$\pm$0.114 m/s (p<0.00l). These results show that there is some relation between the increase of the RI, PI and Vmax of cPDAF and the progress of acute pancreatitis in dogs. Therefore, the measurements of the hemodynamic changes of cPDAF may be a valuable technique for the evaluation of acute pancreatitis in dogs.

• KSBB Journal
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• v.21 no.3
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• pp.224-229
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• 2006

FEMLAB is a powerful interactive environment for modeling, solving all kinds of scientific and engineering problems based on partial differential equations(PDEs). Separation process of chiral compound in HPLC columns was simulated by FEMLAB. To study change of elution profile with isotherm models, non-competitive and competitive Langmuir adsorption isotherm were adopted. Separated material was (R, S)-ibuprofen [(R, S)-2-(4-isobutyl phenyl) propionic acid], an anti-inflammatory agent, which retain the pharmacological activity in the (S)-(+)-enantiomer. Sample concentrations were changed from 0.5 mg/ml to 2.0 mg/ml at a flow rate of 1 ml/min and flow rate varied from 1 ml/min to 3 ml/min at an ibuprofen concentration of 2.0 mg/ml and $20{\mu}l$ of injection volume. Simulated results were well fitted with experimental data.