• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.217-224
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• 1979

The main purpose of the present study is to measure the sound spectra of the underwater noises generated by moving trawl net. An underwater recording system was designed to detect underwater noise generated by moving trawl net. The acoustic analysis was made by a heterodyne analyzer (B & K 2010) and level recorder (B & K 2307). The noises generated by the trawl net are appreciably higher (about 10dB) than the background noise in the presence of the fishing vessel. The frequency distribution of underwater noise was DC-6,300 Hz and predominant frequency range was 100-200 Hz, and maximum sound pressure level was $137\;db(re\;1{\mu}Pa)$. Sound pressure level recorded at the ground rope was higher than that recorded at the head rope. The sound pressure level meosured in the course of hawling was higher than that measured in the course of towing. When tile net is being casted tile sound pressure level showed the lowest value.

• YAKHAK HOEJI
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• v.60 no.2
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• pp.58-63
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• 2016

The purpose of this study is to develop a new preparation process of ginseng berry extracts having high concentrations of ginsenoside Rh1, Rg2, Rg5, F4, a special component of red and black ginseng. Chemical transformation from ginseng saponin glycosides to prosapogenin was analyzed by the HPLC. Extracts of ginseng (Panax ginseng) berry was processed under several treatment conditions including ultrasonication treatments. The content of total saponin reached their heights at 6 hr (UGB-6, 61.760%) of ultrasonication treatment, followed by 10 hr (UGB-10, 53.009%) and 9 hr (UGB-9, 50.652%) of ultrasonication treatment at $100^{\circ}C$. Results of those treatments showed that the quantity of ginsenoside Rh1 increased by over 15% at 10 hr of ultrasonication treatment at $100^{\circ}C$. The results of processing with UGB-10 indicate that the ultrasonication processed ginseng berry extracts that had gone through 10 hr treatments were found to contain the largest amount of ginsenoside Rh1 (15.358%), Rg2 (6.301%), Re (4.567%) and F4 (2.658%). In addition, UGB-6 contained ginsenoside Rg3 (13.632%) at high concentrations. It is thought that such results provide basic information in preparing ginseng berry extracts with functionality enhanced.

• Journal of Sensor Science and Technology
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• v.13 no.5
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• pp.399-404
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• 2004

We report on the technology of formation of sandwich structures based on fullerite films and on experimental results in research of optical and conductivity properties of these sandwich samples. Single crystals of sapphire (100) or silicon were used as substrates. The sandwich specimens were based on the structure M/$C_{60}$/M (M=Cr, Pd, Ag, Al, Cu). The thickness of the fullerite films was about $0.2{\sim}1.0{\mu}m$. The area of the $C_{60}$ film under the top contact was about $1cm^{2}$. The specimens have been investigated by infrared spectroscopy, spectra-photometry, ellipsometry and X-ray diffraction analysis. Measurements of the current/voltage characteristics and research on the temperature dependence of conductivity were performed as well. It was shown that metals such as Cr, Pd, Ag, Al, and Cu penetrate easily into the fullerite films. It appears that these specimens have a large conductivity. For silver/$C_{60}$ and other sandwich structures the conductivities show a semiconductor-like behaviour.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.754-761
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• 2011

The present study numerically investigates two-dimensional flow and heat transfer in the multiple confined impinging slot jet. Numerical simulations are performed for the different Reynolds numbers(Re=100 and 200) in the range of nozzles from 1 to 9 and height ratios(H/D) from 2 to 5, where H/D is the ratio of the channel height to the slot width. The vector plots of velocity profile, stagnation and averaged Nusselt number distributions are presented in this paper. The dependency of thermal fields on the Reynolds number, nozzle number and height ratio can be clarified by observing the Nusselt number as heat transfer characteristic at the stagnation point and impingement surface. The Nusselt number at the stagnation point of the central slot shows unsteadiness at H/D=3 and Re=200. The value of Nusselt number at the stagnation point of the central slot decreases with higher Reynolds number and number of nozzle although overall area averaged Nusselt number increases. Hence careful selection of geometrical parameters and number of nozzle are necessary for optimization of the heat transfer performance of multiple slot impinging jet.

• Journal of the Mineralogical Society of Korea
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• v.1 no.1
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• pp.15-19
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• 1988

In the process of re-checking the phase relations of the Pt-Sb system the previously reported Pt4+Sb phase did not occur. Instead, Pt34Sb7 phase with an average chemical composition (wt%) Pt 89.3, Sb 11.4, total 100.7, has been newly found to exist, and the formula Pt34Sb7 has been tentatively assigned to it, It is pale brownish grey to yellowish grey under refloecting microscope and non-bireflectant, VHN100=225 (206-243). X-ray powder patterns are (d(I/Io)): 2.318(100), 2.293(100), 2.110(30), 1.440(50), 1.390(15), 1.283(5), 1.203(70) and 1.192(40)$\AA$. They are indexable on the basis of tertragonal cell with $\alpha$=3.948(3), c=16.85(1)$\AA$. A question whether the tetragonal Pt34Sb7 is the new phase or a polymorph of the cubic Pt4+Sb phase remains unclear and awaits better X-ray diffraction, electron microprobe analysis and DTA for the Pt4+Sb phase. The Pt3Sb phase reported to be of tetragonal symmetry has been confirmed to exist. It is greyish yellow in air and in oil, very weakly bireflectant, and weakly anisotropic. VHN25=216 (183-240). Its X-ray powder data have been successively indexed on a tetragonal cell with $\alpha$=3.9455(7), c=16.959(5)$\AA$.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.92-100
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• 2015

This study proposes measures to improve management performance of construction projects by re-designing the organizational structures of the Regional Construction Management Administrations of the Ministry of Land, Infrastructure and Transport. The re-designing measures are derived based on the three measures which were established by analyses on status of the Regional Construction Management Administrations, requirements from the current organizational structure, and domestic/overseas examples; the measures are: 1) organizational integration and scope expansion, 2) structural re-organization according to construction projects, and 3) building a knowledge management structure. In order to realize the re-designing measures, sixteen tasks are derived; a milestone is established according to importance, feasibility and lead-lag relationships of these tasks. If these tasks are to be carried out successfully, the management performance of the Regional Construction Management Administrations of the Ministry of Land, Infrastructure and Transport will be expected to improve. Ultimately, the Regional Construction Management Administrations can reduce cost and improve the quality of public service by outsourcing the non-core competence tasks and by concentrating on the construction management for the new infrastructure projects.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.255-261
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• 2018

Aglycon protopanaxatriol (APPT) has valuable pharmacological effects such as memory enhancement and tumor inhibition. ${\beta}$-Glycosidase from the hyperthermophilic bacterium Dictyoglomus turgidum (DT-bgl) hydrolyzes the glucose residues linked to APPT, but not other glycoside residues. ${\beta}$-Glycosidase from the hyperthermophilic bacterium Pyrococcus furiosus (PF-bgl) hydrolyzes the outer sugar at C-6 but not the inner glucose at C-6 or the glucose at C-20. Thus, the combined use of DT-bgl and PF-bgl is expected to increase the biotransformation of PPT-type ginsenosides to APPT. We optimized the ratio of PF-bgl to DT-bgl, the concentrations of substrate and enzyme, and the reaction time to increase the biotransformation of ginsenoside Re and PPT-type ginsenosides in Panax ginseng leaf extract to APPT. DT-bgl combined with PF-bgl converted 1.0 mg/ml PPT-type ginsenosides in ginseng leaf extract to 0.58 mg/ml APPT without other ginsenosides, with a molar conversion of 100%. We achieved the complete biotransformation of ginsenoside Re and PPT-type ginsenosides in ginseng leaf extract to APPT by the combined use of two ${\beta}$-glycosidases, suggesting that discarded ginseng leaves can be used as a source of the valuable ginsenoside APPT. To the best of our knowledge, this is the first quantitative production of APPT using ginsenoside Re, and we report the highest concentration and productivity of APPT from ginseng extract to date.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.683-693
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• 2013

In this study, the mixing characteristics in lid-driven cavity flows were studied numerically by using a hybrid lattice Boltzmann method (HLBM). First, we compared the numerical results from single-relaxation-time (LB-SRT) and multi-relaxation-time (LB-MRT) models to examine their reliability. In most of the cavity flow, the results from both the LB-SRT and the LB-MRT models were in good agreement with those using a Navier-Stokes solver for Re=100-5000. However, the LB-MRT model was superior to the LB-SRT model for the simulation of higher Reynolds number flows having a geometrical singularity with much lesser spatial oscillations. For this reason, the LB-MRT model was selected to study the mass transport in lid-driven cavity flows, and it was demonstrated that mass transport in the fluid was activated by a recirculation zone in the cavity, which is connected from the top to the bottom surfaces through two boundary layers. Various mixing characteristics such as the concentration profiles, mean Sherwood (Sh) numbers, and velocity were computed. Finally, the detailed transport mechanism and solutions for the concentration profile in the cavity were presented.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.2
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• pp.341-348
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• 2013

The auditory thresholds for 7 specimens of the sharp toothed eel Muraensox cinerus were measured at 5 frequencies by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of the sharp toothed eel extended from 80Hz to 300Hz with the best sensitivity around 80Hz and 100Hz. In addition, the auditory thresholds over 200Hz increased rapidly. The mean auditory thresholds of the sharp toothed eel at the test frequencies of 80Hz, 100Hz, 200Hz and 300Hz were 87dB, 86dB, 105dB and 126dB, respectively. Auditory masking was determined for the sharp toothed eel by using masking stimuli with the spectrum level range of about 70~80dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise. The noise spectrum level at the start of masking was distributed at the range of about 64dB within 80~100Hz. Critical ratio ranged from minimum 24dB to maximum 40dB at test frequencies of 80Hz~200Hz.

• Korean Journal of Medicinal Crop Science
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• v.20 no.1
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• pp.63-71
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• 2012

The objectives of this study were to investigate the antioxidant activity of Schizandra chinensis seed oil and its active ingredients. Schizandra chinensis seed oil content extracted with hexane was 36.06%. Schizandra chinensis seed oil extracted with hexane was purified during 20 min at $85^{\circ}C$ with phosphoric acid 0.15% for degumming and 20 min at $80^{\circ}C$ with 3 M NaOH 1% for deaciding. The purified oil consisted of unsaturated fatty acid (88.7%), fatty acid (9.97%), and so on. The major unsaturated fatty acids of purified oil were linoleic acid (71.1%) followed by oleic acid (15.7%), while the main saturated fatty acid was palmitic acid (6.56%). The purified oil was found that contents of phenolic compounds, vitamin A, and E were 1.45 g/100 g, 1494.86 RE/100 g, and 0.58 mg ${\alpha}$-TE/100 g, respectively. Schizandra chinensis seed oil exhibited strong antioxidant activity (91.7%) as compared to grape seed oil and canola seed oil with 87.4% and 85.1% in the DPPH assays. Present results suggest that Schizandra chinensis seed oil could be potentially used as bioactive source for health and preventing numerous diseases.