• Clean Technology
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• v.27 no.3
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• pp.232-239
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• 2021

In order to develop a novel system named "thermal medium and gas circulation type pyrolysis system," this study was conducted to obtain basic data for process simulation before performing the pyrolysis experiment. Polypropylene (PP) was chosen as model material in the basic pyrolysis experiment instead of waste plastic and fluidized sand (hereinafter referred to as "sand"), and it was used as a heat transfer material in the "thermal medium and gas circulation type pyrolysis system." Ni was impregnated as an active catalyst on the sand to promote catalytic pyrolysis. The basic physical properties of PP were analyzed using a thermogravimetric analyzer, and pyrolysis was performed at 600 ℃ in an N₂ atmosphere to produce liquid oil. The distribution of the carbon number of the liquid oil generated through the catalytic pyrolysis reaction was analyzed using GC/MS. We investigated the effects of varying the pyrolysis space velocity and catalyst amount on the yield of liquid oil and the carbon number distribution of the liquid oil. Using Ni/sand, the yield of liquid oil was increased except with the pyrolysis condition of 10 wt% Ni/sand at a space velocity of 30,000 h^-1, and the composition of C₆ ~ C₁₂ hydrocarbons increased. With increases in the space velocity, higher yields of liquid oil were obtained, but the composition of C₆ ~ C₁₂ hydrocarbons was reduced. With 1 wt% Ni/sand, the oil yield obtained was greater than that obtained with 10 wt% Ni/sand. In summary, when 1 wt% Ni/sand was used at a space velocity of 10,000 h^-1, the oil yield was 60.99 wt% and the composition of C₆ ~ C₁₂ hydrocarbons was highest at 42.06 area%.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.603-620
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• 2021

A land nodal seismic system was employed to acquire seismic reflection data using stand-alone cable-free receivers in a land-river area. Acquiring reliable data using this technology is very cost effective, as it avoids topographic problems in the deployment and collection of receivers. The land nodal airgun system deployed on the mouth of the Hyungsan River (in Pohang, Gyeongsangbuk Province) used airgun sources in the river and receivers on the riverbank, with subparallel source and receiver lines, approximately 120 m-spaced. Seismic data collected on the riverbank are characterized by a low signal-to-noise (S/N) and inconsistent reflection events. Most of the events are represented by hyperbola in the field records, including direct waves, guided waves, air waves, and Scholte surface waves, in contrast to the straight lines in the data collected conventionally where source and receiver lines are coincident. The processing strategy included enhancing the signal behind the low-frequency large-amplitude noise with a cascaded application of bandpass and f-k filters for the attenuation of air waves. Static time delays caused by the cross-offset distance between sources and receivers are corrected, with a focus on mapping the shallow reflections obscured by guided wave and air wave noise. A new time-distance equation and curve for direct and air waves are suggested for the correction of the static time delay caused by the cross-offset between source and receiver. Investigation of the minimum cross-offset gathers shows well-aligned shallow reflections around 200 ms after time-shift correction. This time-delay static correction based on the direct wave is found essential to improving the data from parallel source and receiver lines. Data acquisition and processing strategies developed in this study for land nodal airgun seismic systems will be readily applicable to seismic data from land-sea areas when high-resolution signal data becomes available in the future for investigation of shallow gas reservoirs, faults, and engineering designs for the development of coastal areas.

• Journal of the Korean Orthopaedic Association
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• v.52 no.1
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• pp.15-24
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• 2017

Purpose: The aim of this study was to determine the effectiveness of arthroscopic debridement with mini-open ulnar nerve decompression in primary osteoarthritis of the elbow with ulnar neuropathy. Materials and Methods: Between May of 2006 and July of 2014, a total of 43 patients who had undergone surgery for primary osteoarthritis of the elbow with ulnar neuropathy were included in this study. We divided the subjects into two groups according to the method of surgery: group 1 (n=18) received mini-open ulnar nerve decompression only, and group 2 (n=25) received arthroscopic debridement with mini-open ulnar nerve decompression. Patients were assessed for the following clinical outcomes: visual analogue scales (VAS) score, range of motion of the elbow joint, Mayo elbow performance score (MEPS), and disabilities of the arm, shoulder and hand (DASH) at the time before surgery and 6 months after surgery. We analyzed the recovery of the ulnar nerve by the McGowan grade and Bishop rating score preoperatively and at 6 months after the surgery. Results: The VAS score, range of motion of the elbow joint, MEPS, and DASH showed significant statistical difference after the surgery (p<0.05). However, between the 2 groups, there was no significant difference. For the McGowan grade, all cases of both groups-except one case each group-showed at least one grade improvement. Moreover, group 2 showed a greater significant difference than group 1 (p=0.001). At the final follow-up, according to the Bishop rating score, group 2 had a greater significant difference than group 1 (p=0.036). Conclusion: Arthroscopic debridement with mini-open ulnar nerve decompression in primary osteoarthritis of the elbow with ulnar neuropathy is a useful technique, which has several advantages, including the benefits associated with a minimally invasive surgery and also the improvement of elbow joint function and excellent recovery of the ulnar nerve.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1666-1671
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• 2008

The mite-control activities of materials obtained from Pelargonium graveolens oil against Dermatophagoides farinae and D. pteronyssinus were examined using an impregnated fabric disk bioassay and were compared with those shown by commercial benzyl benzoate and N,N-diethyl-m-toluamide (DEET). Purification of the biologically active constituents from P. graveolens oil was done by silica gel chromatography and high performance liquid chromatography. The structures of the active components were analyzed by EI/MS, $^{1}H$-NMR, $^{13}C$-NMR, $^{1}H-^{13}C$ COSY-NMR, and DEPT-NMR spectra, and were identified as geraniol ($C_{10}H_{18}O$, MW 154.25, trans-3,7-dimethyl-2,6-octadien-l-ol) and $\beta$-citronellol ($C_{10}H_{20}O$, MW 156.27, 3,7-dimethyl-6-octen-l-o1). Based on the $LD_{50}$ values, the most toxic compound was geraniol (0.26${\mu}g/cm^{2}$), followed by $\beta$-citronellol (0.28${\mu}g/cm^{2}$), benzyl benzoate (10.03${\mu}g/cm^{2}$), and DEET (37.12${\mu}g/cm^{2}$) against D. farillae. In the case of D. pteronyssinus, geraniol (0.28${\mu}g/cm^{2}$) was the most toxic, followed by $\beta$-citronellol (0.29${\mu}g/cm^{2}$), benzyl benzoate (9.58${\mu}g/cm^{2}$), and DEET (18.23${\mu}g/cm^{2}$). These results suggest that D. farinae and D. pteronyssinus may be controlled more effectively by the application of geraniol and $\beta$-citronellol than benzyl benzoate and DEET. Furthermore, geraniol and $\beta$-citronellol isolated from P. graveolens could be useful for managing populations of D. farinae and D. pterollyssinus.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.12 s.354
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• pp.15-22
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• 2006

In this paper, 1.8V 8-bit 500MSPS Low-power CMOS Digital-to-Analog Converter(DAC) for UWB(Ultra Wide Band) Communication Systeme is proposed. The architecture of the DAC is based on a current steering 6+2 full matrix type which has low glitch and high linearity. In order to achieve a high speed and good performance, a current cell with a high output impedance and wide swing output range is designed. Further a thermometer decoder with same delay time and low-power switching decoder for high efficiency performance are proposed. The proposed DAC was implemented with TSMC 0.18um 1-poly 6-metal N-well CMOS technology. The measured SFDR was 49dB when the output frequency was 50MHz at 500MS/s sampling frequency. The measured INL and DNL were 0.9LSB and 0.3LSB respectively. The DAC power dissipation was 20mW and the effective chip area was $0.63mm^2$.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.1
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• pp.101-124
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• 1996

In this study, we designed the finite element models of mandible with varying their connecting types between the prosthesis on implant fixture and 2nd premolar, which were free-standing case(Mf), precision attachment case(Mp), semiprecision attachment case(Ms) and telescopic case(Mt). The basic model of the designed finite element models, which contained a canine and the 1st & 2nd premolar, was implanted in the edentulous site of the 1st & 2nd molar by two implant fixtures. We applied the load in all models by two ways. A vertical load of 200N was applied at each central fossa of 2nd premolar and 1st implant. A tilting load of 20N with inclination of $45^{\circ}$ to lingual side was applied to buccal cusp tips of each 2nd premolar and 1st implant. And then we analyzed three-dimensional finite element models, making a comparative study of principal stress and displacement in four cases respectively. Three-dimensional finite element analysis was performed for the stress distribution and the displacement using commercial software(IDEAS program) for SUN-SPARC workstation. The results were as follows : 1 Under vertical load or tilting load, maximum displacement appeared at the 2nd premolar. Semiprecision case showed the largest maximum displacement, and maximum displacement reduced in the order of precision attachment, free-standing and telescopic case. 2. Under vertical load. the pattern of displacement of the 1st implant appeared mesio-inclined because of the 2nd implant splinted together. But displacement pattern of the 2nd premolar varied according to their connection type with prosthesis. The 2nd premolar showed a little mesio-inclined vertical displacement in case of free-standing and disto-inclined vertical displacement due to attachment in case of precision and semiprecision attachment. In telescopic case, the largest mesio-inclined vertical displacement has been shown, so, the 1st premolar leaned mesial side. 3. Under tilting load, The pattern of displacement was similar in all four cases which appeared displaced to lingual side. But, the maximum displacement of 2nd premolar appeared larger than that of the first implant. Therefore, there was large discrepancy in displacement between natural tooth and implant during tilting load. 4. Under vertical load, the maximum compressive stress appeared at the 1st implant's neck. Semiprecision attachment case showed the largest maximum compressive stress, and the maximum compressive stress reduced in the order of precision attachment, telescopic and free-standing case. 5 Under vertical load, the maximum tensile stress appeared at the 2nd implant's distal neck. Semiprecision attachment case showed the largest maximum tensile stress, and the maximum tensile stress reduced in the order of precision attachment, telescopic and free-standing case. 6. Under vertical load or tilting load, principal stress appeared little between natural tooth & implant in free-standing case, but large principal stress was distributed at upper crown and distal contact site of the 2nd premolar in telescopic case. Principal stress appeared large at keyway & around keyway of distal contact site of the 2nd premolar in precision and semiprecision attachment case, appearing more broad and homogeneous in precision attachment case than in semiprecision attachment case.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.21-26
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• 2005

Although the sesame lignans, sesamol, have been shown to possess antioxidative activity, less is known about the metabolism and antioxidative properties of sesamol, a major constituent of sesame oil. To determine the ability of sesamol to act as an antioxidant in vivo, we fed rats a diet containing 0.5% sesamol for 3 wk and studied its metabolism and its effects on oxidative stress. Body weight gain and weight of liver, kidneys were significantly higher in the rats fed sesamol than in rats fed the control diets. GST and GST-Px activities in rat liver microsomes were higher in rats fed sesamol and CAT activities were found to be significantly increased in rats fed sesamol. The formation of TBARS was decreased in the liver of rat fed the 0.5% sesamol diet than in controls. We detected sesamol metabolites in liver and kidneys of rats fed sesamol and its metabolites were present as conjugated glucuronides and sulfates. In contrast, not detected sesamol peak in other organs such as colon, small intestine and pancreas.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.318-323
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• 2015

The aim of this study was to assess the association of metabolic syndrome and Vitamin D in Korean adults. The study subjects were Korean menopausal woman (n=4,340) who participated in the Korea National Health and Nutrition Examination Survey 2010~2012. After adjusting for factors such as age, body mass index, total cholesterol, smoking, and regular exercise, the mean 25(OH)D levels ($M{\pm}SE$) decreased with increasing metabolic syndrome score (MSS) (MSS 0, $18.18{\pm}0.29ng/Ml$; MSS 1, $18.09{\pm}0.21ng/mL$; MSS 2, $18.07{\pm}0.19ng/mL$; MSS 3, $18.04{\pm}0.21ng/mL$; MSS ${\geq}4$, $17.27{\pm}0.23ng/mL$), and the mean 25(OH)D level ($M{\pm}SE$) for metabolic syndrome ($17.66{\pm}0.16ng/mL$) decreased in comparison to non-metabolic syndrome ($18.11{\pm}0.14ng/mL$). In conclusion, our results suggest that an increase in metabolic syndrome score or metabolic syndrome are inversely associated with the vitamin D levels.

• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.137-142
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• 1998

Helicobacter pylori is a Gram-negative bacterium which causes chronic gastritis and is associated with gastric ulcer, duodenal ulcer and gastric carcinoma. In the process of screening of antibacterial activities against H. pylori from soil microorganisms, fungus No. 60686 was isolated. After fermentation of No.60686, the antibacterial compound was isolated, purified and followed by extraction of mycelium with organic solvents, acetone and ethyl acetate, through silica gel chromatography, LH-20 gel chromatography and HPLC. As a result of the structural analyses of the compound by IR, $^1$H- and $^{13}$C-NMR, FAB/Mass spectrophotometer, the compound having the antimicrobial activity was identified as chaetoglobosin A ($C_{32}H_{36}N_2O_5$), a cytochalasan derivative. The antimicrobial activity of chaetoglobosin A was tested against Gram-positive and negative bacteria by paper disk method. Among the test strains of 9 Gram-positive bacteria and 18 Gram-negative bacteria containing 4 H. pylori strains, the growth of 4 H. pylori strains and 3 S. aureus strains (SG 511, 285 and 503) was only inhibited by chaetoglobosin A. Also it was shown that its growth inhibition against H. pylori strains was stronger than that against S. aureus strains at the treatment of the same concentration. Therefore it was concluded that chaetoglobosin A has a specific growth inhibition against H. pylori of the tested bacteria.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.319-328
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• 1995

This study was carried out to investigate the resistance mechanism by three different kinds of procymidone-resistant and susceptible isolates of Botrytis cinerea which had been collected from green houses. The average resistance level of the resistant strains was 1,000 times higher than that of susceptible ones. Also, it was revealed that the resistance was not originated from components excreted by Botrytis cinerea, based on the result obtained from the treatment with piperonyl butoxide and triphenyl phosphate as an inhibitor of monooxygenase and esterase, respectively. The total lipod content of resistant strains was 1.3 times higher than that of susceptible ones, among fatty acids, palmitic acid, stearic acid, and linoleic and being 3.0, 2.5, and 2.0 times higher, respectinely. Also slight differences in sterol contents and components were observed. The crude chitin content was slightly higher in susceptible strains but contents of N-acetyl glucosamine, a hydrolysate of chitin, were about 2 times higher in resistant ones.