• Journal of the Korean Geophysical Society
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• v.5 no.1
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• pp.41-50
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• 2002

In order to delineate distribution of the basement in the vicinity of a Quaternary fault outcrop near the Gamsansa temple in Gyeongju, we conducted a seismic refraction survey along a 188 m profile with a 4 m receiver interval. Through tomographic inversion, we define four layers with refraction velocities of approximately 350 m/s, 600 m/s, 1,100 m/s and 2,400 m/s, respectively. We depict a reversed fault at a location of 40 m apart from the base station of the profile and interpret a fracture zone related to fault movements in the NNW of the profile.

• Toxicological Research
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• v.19 no.3
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• pp.181-187
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• 2003

Effects of repeated treatment with butylated hydroxyanisole (BHA) on the induction of glutathione S-transferases (GSTs) and teratogenicity of cyclophosphamide were investigated in rats. Pregnant rats were orally treated with BHA (50 mg/kg) for 7 days, from days 6 to 12 of gestation, and intraperitoneally challenged with cyclophosphamide (15 mg/kg) 2 hr after the final treatment. On day 20 of gestation, the maternal and fetal abnormalities were examined. Separately, a part of rats was sacrificed for the assay of hepatic and placental GSTs activities on day 12 of gestation following 7-day treatment with BHA. Cyclophosphamide, administered on day 12 of gestation, induced 43.2% of fetal death and resorption, and 100% of malformations in live fetuses, in contrast to low fetal resorption (8.7%) and malformations (8%) in control group. The malformations include cranial defect and exencephaly (100%), micrognathia and tongue extrusion (100%), limb defects (40%), renal pelvic dilatation (39%), and cleft palate (15%). Interestingly, BHA induced GSTs activities by 62% and 46% over the control in liver and placenta, respectively, and remarkably reduced the fetal resorption (13.9%) and malformations, resulting in 62% of cranial defect and exencephaly, 68% of micrognathia and tongue extrusion, 29% of limb defects, and 14% of renal pelvic dilatation. Taken together, it is suggested that a long-term pretreatment with BHA could substantially prevent fetuses from abortion and malformations following intrauterine exposure to teratogens including cyclophosphamide by inducing phase II antioxidant enzymes such as GSTs.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.234-239
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• 2023

Waste from the food is a challenge to the environment all over the globe, hence there is need to be recycled. There is a great deal of renewable energy potential in the biomass of vegetables and fruits, which can be used to generate power and steam, as well as fuel for human consumption and laboratory solvents. To maintain the nutritional, antioxidative, and functional qualities of sapota fruit, wine was made by fermenting it with wine yeast (Saccharomyces cerevisiae). The wine's approximate composition was as follows: total soluble solids, 2.38°Brix; total sugar, 3.8 g/100 ml tartaric acidity (TA), 1.29 g tartaric acidity total phenolics, 0.21 g/100 mL; pH, 3.02; acid/100 mL; pH, 3.02; total phenolics, 0.21 g/100 mL; 22 g/100 ml -carotene; 1.78 g/100 ml ascorbic acid mg/100 ml; 0.64 mg/100 ml lactic acid; and The ethanol percentage is 8.23% (v/v). The sapota wine was delicious. A DPPH-scavenging 2, 2-diphenyl-1picryl hydroxyl (DPPH) at a dosage of 250 g/ml, the activity was 46%. Infrared alcohols, phenethylamines, and other compounds were discovered via spectroscopy.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1444-1445
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• 2008

최근 Wireless Local Area Network(WLAN), Wide-band Code Division Multiple Access(WCDMA), CDMA2000, Bluetooth 등 다양한 모바일 통신 시스템에 대한 수요가 증가하고 있다. 이와 같은 모바일 통신 시스템에는 70dB이상의 SFDR(Spurious Free Dynamic Range)을 가진 ADC(Analog-to-Digital Converter)가 사용된다. 본 논문에서는 모바일 통신 시스템을 위한 SFDR 70dBc의 성능을 제공하는 10비트, 100Msps 파이프라인 ADC를 제안한다. 제안한 ADC는 요구되는 해상도 및 속도 사양을 만족시키기 위해 3단 파이프라인 구조를 채택하였으며, 입력단 SHA(Sample and Hold)회로에는 Nyquist 입력에서도 10비트 이상의 정확도로 신호를 샘플링하기 위해 부트스트래핑 기법 기반의 샘플링 스위치를 적용하였다. residue amplifier 회로에는 전력을 줄이기 위해 8배 residue amplifier 대신 3개의 2배 ressidue amplifier를 사용하였다. ADC의 높은 사양을 만족시키기 위해서는 높은 이득을 가지는 op-amp가 필수적이다. 제안한 ADC 는 0.18um CMOS 공정으로 설계되었으며, 100Msps의 동작 속도에서 70dBc 수준의 SFDR과 60dB 수준의 SNDR(Signal to Noise and Distortion Ratio)을 보여준다.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.534-542
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• 1992

Trypsin inhibtor produced by Streptomyces sp. S-217 was purified by solvent extraction and various column chromatographies. and physico-chemical properties of the inhibitor were investigated. Inhibitor complex was formed for incubation of 10 min. Streptomyces 5-217 showed the highest production of trypsin inhibitor when it was cultivated at $37^{\circ}C$ for 66 hr in the medium containing 2% mannitol & 0.9% peptone, pH 7.0. Trypsin inhibitor was purified by column chromatography and high performance liquid chromatography. Trypsin inhibitor indicated the maxium wavelength at 215 nm and solubilities in water, methanol and dimethyl sulfoxide were 95, 70 and 75%, respectively. The concentration of 50% inhibition ($IC^{50}$) was 15 $\mu$g/ml. The inhibitor was stable on heating at $100^{\circ}C$ for 60 min in pH 5~9 and was more stable in alkaline region than acidic region.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.166-172
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• 2003

Rockwool slabs used for hydroponic cultures are expected to have potential to be reused after breakdown as a growing medium component for hydroponic culture of vegetables and cut flowers, pot plants, or plug plants. This study was conducted to test the feasibility of using particles of used rockwool slabs (PURS) mixed with woodchips for growing plug seedlings of ‘Nokkufang’ pepper. In the first experiment growth of pepper seedlings was tested in media of steam sterilized PURS mixed with chestnut woodchips (CW), which was weatherized for six months and screened through 2.8 mm or 5.6 mm sieves, at 100:0, 75:25, 50:50, 28:75 or 0:100 (%, v/v). In the second experiment growth of pepper seedlings was tested in 20 different media containing steam sterilized PURS mixed with 4 mm chestnut woodchips (CW), 4 mm pinc woodchips (PW), coir, peatmoss, or perlite. In the first experiment, there were no significant growth differences as affectcd by particle size of CW, while the overall best growth was achieved il1 the control and l00% PURS. In the second experiment, seedling growth was enhanced as compared to the control in 100% PURS or PURS mixed with peatmoss, coir, or perlite. In contrast, growth was suppressed as the proportion of peatmoss or coir mixed with PURS decreased and the proportion of CW increased. Growth was better in the PURS + peatmoss than in the 100% PURS or PURS + coir, and when woodchips were mixed with coir than peatmoss.

• Natural Product Sciences
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• v.13 no.4
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• pp.279-282
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• 2007

The aim of the present study was to investigate the various chemical components present in the cone volatile oil of Cupressus macrocarpa and also determine its antimicrobial activity. Totally 13 compounds were identified with 99.99% by GC-MS analysis. The major compounds identified were terpinene-4-ol (19.42%), dinopol (15.63%), ${\alpha}$-pinene (13.58%), and ${\beta}$-pinene (12.16%). The antimicrobial activity was carried out for the oil and a 2% cream formulation using cup plate method by measuring the zone of inhibition. The gram positive organisms used were Bacillus subtilis, Staphylococcus aureus, Bacillus megaterium, and Bacillus cogulans. The gram negative organisms used were Escherichia coli, Kleibseilla pneumonia, Pseudomonas aeruginosa and Salmonella typhi. In vitro antifungal studies were also carried out by using organisms, Candida albicans, Aspergillus flavus, Trichoderma lignorum and Cryptococcus neoformans. The standard drugs used were penicillin ($100{\mu}g/mL$), gentamycin ($100{\mu}g/mL$) and griseofulvin ($100{\mu}g/mL$) for gram positive bacteria, gram negative bacteria and fungi respectively. Both oil and cream formulation showed good activity against fungi than bacteria. This study is being reported for the first time on cone volatile oil of this plant.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.183-192
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• 2018

It is imperative to inject carbon dioxide($CO_2$) into an aquifer for alleviating the emission of $CO_2$. However, faults in the aquifer can be reactivated due to pressure increasement. Analyses of pressure change of the aquifer is necessary to prevent the fault reactivation. In this research, we assess the stability of an aquifer in Pohang Yeongil bay by investigating the pressure variation of faults EF1 and EF2. Two scenarios, which repeat $CO_2$ injection and suspension during two years, are simulated. Each scenario includes cases of injection rates of 20, 40, and 100 tons/day. In addition, we analyze planned and predicted injection rates for each case. In case of 20 tons/day, the maximum pressure of faults is 65% of the reactivation pressure. Even if daily injection rates are increased to 40 and 100 tons/day, the maximum pressures are 71% and 80% of the reactivation pressures, respectively. For 20 and 40 tons/day cases, planned injection rates almost accord with predicted injection rates during whole simulation period. On the other hand, predicted injection rates are smaller than planned injection rates for the 100 tons/day case due to bottom-hole pressure limit of the injection well.

• Research in Plant Disease
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• v.25 no.3
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• pp.114-123
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• 2019

QD LED has an ideal light source for growing crops and can also be used to control plant pathogenic microorganisms. The mycelial growth inhibition effect of QD LED light on Rhizoctonia solani, Phytophthora drechsleri, Sclerotinia sclerotiorum, Sclerotinia minor, Botrytis cinerea, Fusarium oxysporum, Pectobacterium carotovorum, and Xanthomonas campestris were investigated. According to the results, BLUE (450 nm) light, suppressed S. sclerotiorum by 16.7% at 50 cm height from the light source, and 94.1% mycelial growth at 30 cm height. Mycelial growth of Sclerotinia minor was inhibited by 80.4% at 50 cm height and 36.3% at 50 cm height in B. cinerea. S. minor, and B. cinerea was inhibited by 100% mycelial growth at a height of 30 cm from the light source. At 15 cm height, all three pathogens (B. cinerea, S. minor, and S. sclerotiorum) was inhibited by 100%. QD RED (M1) and QD RED (M2) light suppressed mycelial growth of S. minor and B. cinerea by 100% at 30 cm and 15 cm height from the light source. For S. sclerotiorum, QD RED (M1) and QD RED (M2) showed 75.2% and 100% inhibition, respectively. Further experiment was conducted to know the suppression effect of lights after inoculating the fungal pathogens on lettuce crop. According to the results, QD RED (M2) suppressed the S. sclerotiorum by 59.9%. In addition, Blue (450 nm), QD RED (M1), and QD RED (M2) light reduce the infestation by 59.9%. In case of B. cinerea, disease reduction was found 84% by BLUE (450 nm) light. Results suggest that the growth inhibition of mycelium increases by Quantum dot LED light.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.238-244
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• 2012

Toxic effects of heavy metal (Pb, Cr, As) were examined by the hatching rates of fertilized eggs in the oliver flounder, Paralichthys olivaceus. Eggs were exposed to Pb, Cr, As (0, 10, 100, 500, 1,000, 2,500, 5,000 ppb) and then normal hatching rates were investigated after 48 h. The normal hatching rates in the control condition (not including heavy metal) were greater than 80%, but suddenly decreased with increasing of heavy metal concentrations. Pb, Cr and As reduced the normal hatching rates in concentration-dependent way and a significant reduction occurred at concentration grater than 100, 100, 500 ppb, respectively. The ranking of heavy metal toxicity was Cr>As>Pb, with $EC_{50}$ values of 415, 518 and 1,029 ppb, respectively. The no-observed-effect-concentration (NOEC) and lowest-observed-effect-concentration (LOEC) show each 100 bbp and 500 ppb of normal hatching rates in exposed to Pb and As. The NOEC and LOEC of normal hatching rates in Cr were 10 ppb and 100 ppb, respectively. From these results, the normal hatching rates of P. olivaceus have toxic effect at greater than the 100 ppb concentrations in Pb, As and the 10 ppb concentrations in Cr in natural ecosystems. These results suggest that biological assay using the normal hatching rates of P. olivaceus are very useful test method for the toxicity assessment of a toxic substance as heavy metal in marine ecosystems.