• Journal of Korean Society of Environmental Engineers
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• v.38 no.6
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• pp.291-298
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• 2016

Electrochemical water treatment process as a useful treatment method for the removal of non-degradable matter has been consistently studied for several decades. Key process of electrochemical water treatment are oxidation reaction from an anode and reduction from a cathode. In this study, the effect of pre-treatment methods in the insoluble electrode manufacturing process for the water treatment has been evaluated for the life time of electrode The results of this study showed that pre-treatment methods of a base metal such as surface roughness, clean method and interlayer formation influenced to life time of electrode when the same condition (catalyst electrode layer coating method and material system) was applied for pre-treatment methods. This study was conducted by using $IrO_2/Ti$ electrode In the test of sand-blasting process, an electrode manufactured by using sanding media of different sizes resulted in the most effective electrode life time when the size of alumina was used for $212{\sim}180{\mu}m$ praticle size (#80). The most effective method was considered using arc plasma in the additional roughness control and cleaning process, sputtering method to form Ta type interlayer formation process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.1
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• pp.25-31
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• 2009

This study was carried out to investigate the mutagenic, antimutagenic, cytotoxicity and antitumor effects of Adenophora triphylla (AT). AT was extracted with 70% ethanol and then further fractionated to hexane, chloroform, ethyl acetate, butanol and water. Antimutagenic, cytotoxicity and antitumor effects of AT extracts were measured by using Ames test, SRB method, and the tumor growth inhibition test. AT extracts did not show any mutagenicity in the Ames test; however, 70% ethanol extracts and its fractions had strong antimutagenic effects against mutation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 4-nitroquinoline-1-oxide (4NQO). The ethyl acetate fraction of AT (200 ${\mu}g$/plate) showed approximately 66.5% inhibitory effect on the mutagenesis induced by 4NQO against TA98 strain, whereas 83.3% and 75.1% inhibitions were observed on the mutagenesis induced by MNNG and 4NQO against TA100 strain. In anticancer effects, the cytotoxicity of AT extract and its fractions against cancer cell lines including human cervical adenocarcinoma (HeLa), human hepatocellular carcinoma (Hep3B), human breast adenocarcinoma (MCF-7), human gastric carcinoma (AGS), human lung carcinoma (A549) and transformed primary human embryo kidney (293) were investigated. The treatment of 1 mg/mL AT ethyl acetate faction had the highest cytotoxicity of 79.9%, 74.9%, 66.0%, 71.0% and 74.3% against HeLa, Hep3B, MCF-7, AGS and A549 cells, respectively. In contrast, the extract and its fractions showed only $3{\sim}36%$ cytotoxicity for a normal human kidney cell line (293). In vivo anti-cancer effect of Adenophora triphylla extract was tested using Balb/c mice transplanted sarcoma-180 cells. Adenophora triphylla ethyl acetate fraction showed the highest inhibition rate of 37.2% at the 50 mg/kg concentration.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.51-56
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• 1986

It is important to measure and protect from the radiation space dose and induced activity at the high energy medical linear accelerator facilities. These are to consider the additional risk to patients undergoing treatment, machine operators and staff members. Measurements of the space dose distribution and induced radioactivity at the 18 MeV medical linear accelerator facility in the Yonsei Cancer Center. 1. Exposure space dose for 300 rads monitor doses of 18 MeV electron are measured as 50 mR at 1 meter from patients. 2. Exposure space dose for 300 rads monitor doses of 10 MV X-ray are detected as 350 mR at 1 meter from phantom. 3. Induced radioactivity by photonuclear reaction was measured as 0.65 mR/hr from collimater after 30 Gy(3,000 rads) irradiated. 4. Analyzing the decay curves and energy spectrum of induced radioactivity, detected a few materials to be activated by photoneutron reaction, $^{65}Cu({\gamma}{\cdot}n)\;^{64}Cu,\;^{186}W({\gamma}{\cdot}n)\;^{185}W,\;^{181}Ta({\gamma}{\cdot}n)\;^{180}Ta,\;^{199}Au({\gamma}{\cdot}n)\;^{198}Au$.

• Archives of Plastic Surgery
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• v.48 no.4
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• pp.378-383
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• 2021

Conjoined twins are rare, and each set of conjoined twins has a unique conjoined anatomy. It is necessary to perform separation to increase the chance of patient survival. Tissue expansion is an advanced technique for providing sufficient soft tissue and skin for wound closure. We report the successful application of rapid tissue expansion in 10-month-old xipho-omphalopagus conjoined twins in Vietnam. A tissue expander was placed on the anterior body between the sternum and umbilicus with a baseline of 70 mL sterile saline (0.9% NaCl). The first injection into the tissue expander began on the 6th day after expander insertion, and injections continued every 2 days with approximately 30-70 mL per injection according to the expansion of the skin. The expander reached 335 mL after six injections and within 10 days. In order to prepare for surgical separation, expansion was completed on the 15th day after insertion. The expanded skin area was estimated to be 180 cm², which was sufficient to cover both patients' skin deficiencies. The twins presented for surgical separation 6 days following the completion of tissue expansion. Both babies were discharged in good health 1 month after separation.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.172-179
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• 2003

This study was carried out to find the preventive medical and therapeutic effects of Sarcodon asparatus on adult disease by employing several biological and biochemical assays. Nitrate scavenging ability(NSA) of Sarcodan asparatus extracts was displayed up to 99.9% at pH 1.2 in a dose-dependent manner. They also had 90.4% electron donating ability(EDA) at the concentration of 0.1 mg/mL. Extracts of Sarcodon asparatus were also able to function as a powerful antioxidant at all concentrations(0.01∼l.0 mg/mL). Furthermore, we observed that 1 mg/mL concentration of the extracts was more powerful than BHT, With respect to fibrolytic activity, Sarcodon asparatus showed 1,843.8 unit/g, which was higher than streptokinase(1,189 unit/g). The inhibitory effects of the extracts on angiotensin converting enzyme, measured by the normal and pretreatment methods, were 53 and 58%, respectively. We also performed cytotoxicity effect of Sarcodon asparatus extracts on a various cancer cell lines. The growth inhibitory effects of the extracts(5.0 mg/mL) on A549, HeLa, AGS, and SK-Hep-1 cells were 78.9, 55.3, 69.0, and 42.5 %, respectively. Interestingly, Sarcodon asparatusextracts induced mutation on Salmonella typhimurium TA98 and TA100 when Ames test was done.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.279-283
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• 2013

This work was carried out to evaluate the effect of preharvest sprayable 1-methylcyclopropene (1-MCP: $Harvista^{TM}$) treatment on the fruit quality attributes in cold stored 'Gamhong' (Malus domestica Borkh) apples. Preharvest sprayable 1-MCP treatment did not affect fruit qualities at harvest but titratable acidity (TA) was higher in fruit treated 10 days before harvest (DBH) than in control. During cold storage, fruit firmness and TA were higher in 1-MCP treated fruit than in control fruit as storage duration progressed, while SSC was not affected. Internal ethylene concentration (IEC) levels were not different among treatments at harvest. While the IEC level in control fruit reached to $58.3{\mu}L{\cdot}L^{-1}$ after 6 month cold storage, the IEC levels in 1-MCP treated fruit ranged from 18.2 to $25.0{\mu}L{\cdot}L^{-1}$. Therefore, this result indicates that preharvest sprayable 1-MCP treatment should be another promising approach to retain fruit quality attributes in long-term cold stored 'Gamhong' apples.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.257-257
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• 2016

최근에 메모리의 초고속화, 고집적화 및 초절전화가 요구되면서 resistive random access memory (ReRAM), ferroelectric RAM (FeRAM), phase change RAM (PRAM)등과 같은 차세대 메모리 기술이 활발히 연구되고 있다. 다양한 메모리 중에서 특히 resistive random access memory (ReRAM)는 빠른 동작 속도, 낮은 동작 전압, 대용량화와 비휘발성 등의 장점을 가진다. ReRAM 소자는 절연막의 저항 스위칭(resistance switching) 현상을 이용하여 동작하기 때문에 SiOx, AlOx, TaOx, ZrOx, NiOx, TiOx, 그리고 HfOx 등과 같은 금속 산화물에 대한 연구들이 활발하게 이루어지고 있다. 이와 같이 다양한 산화물 중에서 AlOx는 ReRAM의 절연막으로 적용되었을 때, 우수한 저항변화특성과 안정성을 가진다. 하지만, AlOx 박막을 형성하기 위하여 기존에 많이 사용되어지던 PVD (physical vapour deposition) 또는 CVD (chemical vapour deposition) 방법에서는 두께가 균일하고 막질이 우수한 박막을 얻을 수 있지만 고가의 진공장비 사용 및 대면적 공정이 곤란하다는 문제점이 있다. 한편, 용액 공정 방법은 공정과정이 간단하여 경제적이고 대면적화가 가능하며 저온에서 공정이 이루어지는 장점으로 많은 관심을 받고 있다. 본 연구에서는 sputtering 방법과 용액 공정 방법으로 형성한 AlOx 기반의 ReRAM에서 메모리 특성을 비교 및 평가하였다. 먼저, p-type Si 기판 위에 습식산화를 통하여 SiO2 300 nm를 성장시킨 후, electron beam evaporation으로 하부 전극을 형성하기 위하여 Ti와 Pt를 각각 10 nm와 100 nm의 두께로 증착하였다. 이후, 제작된 AlOx 용액을 spin coating 방법으로 1000 rpm 10 초, 6000 rpm 30 초의 조건으로 증착하였다. Solvent 및 불순물 제거를 위하여 $180^{\circ}C$의 온도에서 10 분 동안 열처리를 진행하였고, 상부 전극을 형성하기 위해 shadow mask를 이용하여 각각 50 nm, 100 nm 두께의 Ti와 Al을 electron beam evaporation 방법으로 증착하였다. 측정 결과, 용액 공정 방법으로 형성한 AlOx 기반의 ReRAM에서는 기존의 sputtering 방법으로 제작된 ReRAM에 비해서 저항 분포가 균일하지는 않았지만, 103 cycle 이상의 우수한 endurance 특성을 나타냈다. 또한, 1 V 내외로 동작 전압이 낮았으며 104 초 동안의 retention 측정에서도 메모리 특성이 일정하게 유지되었다. 결론적으로, 간단한 용액 공정 방법은 ReRAM 소자 제작에 많이 이용될 것으로 기대된다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.177-180
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• 2002

Thickness dependence of crystallographic orientation of diol based sol-gel derived PZT(52/48) films on dielectric and piezoelectric properties was investigated The thickness of each layer by one time spinning was about 0.2 $\mu\textrm{m}$, and crack-free films was successfully deposited on 4 inches Pt/Ti/SiO$_2$/Si substrates by 0.5 mol solutions in the range from 0.2 $\mu\textrm{m}$ to 3.8 $\mu\textrm{m}$. Excellent P-E hysteresis curves were achieved without pores or any defects between interlayers. As the thickness increased , the (111) preferred orientation disappeared from 1$\mu\textrm{m}$ to 3 $\mu\textrm{m}$ region, and the orientation of films became random above 3 $\mu\textrm{m}$. Dielectric constants and longitudinal piezoelectric coefficient d$\_$33/, measured by pneumatic method were saturated around the value of about 1400 and 300 pC/N respectively above the thickness of 0.8 7m. A micromachined piezoelectric cantilever have been fabricated using 0.8 $\mu\textrm{m}$ thickness PZT (52/48) films. PZT films were prepared on Si/SiN$\_$x/SiO$_2$/Ta/Pt substrate and fabricated unimorph cantilever consist of a 0.8 fm thick PZT layer on a SiNx elastic supporting layer, which becomes vibration when ac voltage is applied to the piezoelectric layer. The dielectric constant (at 100 kHz) and remanent polarization of PZT films were 1050 and 25 ${\mu}$C/$\textrm{cm}^2$, respectively. Electromechanical characteristics of the micromachined PZT cantilever in air with 200-600 $\mu\textrm{m}$ lengths are discussed in this presentation.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.273-284
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• 2018

Purpose: Conventional headland turning typically requires repeated forward and backward movements to move the farming equipment to the next row. This research focuses on developing an upland agricultural robot with an optimized headland turning mechanism that enables a $180^{\circ}$ turning positioning to the next row in one steering motion designed for a two-wheel steering, four-wheel drive agricultural robot named the HADA-bot. The proposed steering mechanism allows for faster turnings at each headland compared to those of the conventional steering system. Methods: The HADA-bot was designed with 1.7-m wide wheel tracks to travel along the furrows of a garlic bed, and a look-ahead path following algorithm was applied using a real-time kinematic global positioning system signal. Pivot turning tests focused primarily on accuracy regarding the turning radius for the next path matching, saving headland turning time, area, and effort. Results: Several test cases were performed by evaluating right and left turns on two different surfaces: concrete and soil, at three speeds: 1, 2, and 3 km/h. From the left and right side pivot turning results, the percentage of lateral deviation is within the acceptable range of 10% even on the soil surface. This U-turn scheme reduces 67% and 54% of the headland turning time, and 36% and 32% of the required headland area compared to a 50 hp tractor (ISEKI, TA5240, Ehime, Japan) and a riding-type cultivator (CFM-1200, Asia Technology, Deagu, Rep. Korea), respectively. Conclusion: The pivot turning trajectory on both soil and concrete surfaces achieved similar results within the typical operating speed range. Overall, these results prove that the pivot turning mechanism is suitable for improving conventional headland turning by reducing both turning radius and turning time.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.791-797
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• 2007

We studied the inhibitory effect of solvent fractions from doenjang on mutagenicity using Salmonella typhimurium TA100 in Ames test. We also investigated the effect of solvent fractions from doenjang on the growth of tumor cells and the production of interleukin-2 (IL-2). The treatment of dichlorormethane and ethylacetate fractions (2.5 mg/assay) from doenjang to Ames test system inhibited aflatoxin B$_1$ (AFB$_1$) induced mutagenicity by 96% and 97%, respectively, and showed a higher antimutagenic effect than other solvent fractions. In case of N-methyl-N'-nitro-N-nitrosoguamidine (MNNG) induced mutagenicity, the ethylacetate fraction showed the highest inhibitory effect (by 75%) among the other sol-vent fractions, although the inhibitory effect was not stronger compared to AFB$_1$ induced mutagenicity. The treatment of dichloromethane and ethylacetate fractions markedly inhibited the growth of Yac-1 (by 80% and 94%, respectively) and sacroma-180 cancer cells (by 60% and 96%, respectively) after 4 days of incubation at 37${\circ}$C. To elucidate the immunological mechanism of antitumor activity of doenjang, spleen cells of Balb/c mouse were exposed to the dichloromethane and ethyl-acetate fractions for 24 hours at 37${\circ}$C . The culture supernatants following the treatment of djchloromethane and ethylacetate factions to spleen cells increased the production of IL-2. These results indicated that the anticarcinogenic effect of doenjang was mediated by the production of IL-2.