• Ocean and Polar Research
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• v.41 no.1
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• pp.11-18
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• 2019

This acoustic experiment noted that fish species in Chilam-Gijang marine ranching area were more densely distributed in the pelagic zone during nighttime than daytime. In each season, the gill nets caught 15 different fish species and the estimated average target strengths were -44.0 dB and -44.4 dB for autumn and winter surveys, respectively. The estimated autumn fish biomass were 7.7 tons and 26.0 tons during daytime and nighttime, respectively. Winter biomass was 2.27 tons and 30.97 tons during daytime and nighttime, respectively. Different fish species form schools that exhibit different movements and behaviors, and thereby occupy varying water layers. These results explained the estimated fish biomass, and variation with seasons and time of the surveys around artificial reefs in Chilam Bay, Korea.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.150-157
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• 1996

In this paper, to develop a smart CAD/CAM system for systematically performing from the 3-D solid shape design of products to the CNC cutting operation of products by a machining center, a B-Rep solid modeler is realized based on the half edge data structure. Because the B-Rep solid modeler has the various capabilities related to the solid definition functions such as the creation operation of primitives and the translational and rotational sweep operation, the solid manipulation functions such as the split operation and the Boolean set operation, and the solid inversion function for effectively using the data structure, the 3-D solid shape of products can be easily designed and constructed. Also, besides the automatic generation of CNC code, the B-Rep solid modeler can be used as a powerful tool for realizing the automatic generation of finite elements, the interfer- ence check between solids, the structural design of machine tools and robots and so on.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.2
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• pp.133-139
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• 2018

Chemically damaged hair is vulnerable to external stimuli in daily life due to the weakened physical properties of the hair strand itself. The purpose of this work was to determine whether chemical conjugation between hair keratin proteins restores tensile strength and thus results inpreventing further deterioration under repeated combing. A model damaged hair tress was produced by a typical perm-process. Then, it was internally crosslinked by the bifunctional crosslinker (3-aminopropyl)triethoxysilane (APTES), via both silane coupling and carbodiimide chemistry. Physical properties, including tensile strength, Young's modulus, and plateau stress, were measured to verify the effect of internal crosslinking, and the existence of crosslinking was verified by Fourier transform infrared (FT-IR) spectroscopy. The degrees of hair breakage and split ends were evaluated by repeated combing-drying tests. Physical properties of chemically damaged hair were restored by internal crosslinking. Successful crosslinking of APTES via both silane coupling and carbodiimide chemistry was verified by FT-IR spectra. Prevention of breakage and split ends after repeated combing with heat was observed. Human hair can be weakened by chemical damage including perm-processing, so restoring such properties is a major issue in the hair care industry. This work shows that internal crosslinking of damaged hair via chemical conjugation would be a potent method to restore the healthy hair.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.4
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• pp.404-409
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• 1999

The in situ target strengths of, maurolicus muelleri were measured by the split beam echo sounder system at the frequency of 38kHz.Target strengths were measured during the night time in order to obtain the pure separated echoes from the scattered individual. And also it was to establish reasonable threshold due to taking the signals like as the planktons and etc.Since Maurolicus muelleri is a typical micronektonic fish, they mainly consisted of deep scattering layers(DSLs), and had a vertical migration perrodically during daytime and at night.We found that the Maurolicus muelleri occupied about 99% of total catch. Total length ranged from 4.5 to 5.7cm with a mean of 5.2cm and a standard deviation of 0.22cm.The target strengths of Maurolicus muelleir ranged from -60.4 to - 52.7dB and -59.2 to - 52.5 dB in the water layer of 10~30m and 30~50m depth, perspectively. Mean target strength was -57.1dB/fish and -28.5dB/kg. The target strength had the relation with the total length of the fish as, TS=20logL-71.4.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.168-175
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• 2013

This paper presents compact dual-band WLAN filter and filter module. They were developed by embedding all of the passive lumped elements into a LTCC substrate. In order to reduce the size/volume of the filter and avoid EM parasitic couplings between the passive elements, the proposed filter was designed using a 3rd order Chebyshev circuit topology and J-inverter transformation technology. The 3rd order Chebyshev bandpass filter was firstly designed for the band-selection of the 802.11b and was then transformed using finite transmission zeros technologies. Finally, the dual-band filter was realized by adding two notch resonators to the 802.11b filter circuit for the band-selection of the 802.11a/g. The maximum insertion losses in the lower and higher passbands were better than 2.0 and 1.3 dB with minimum return losses of 15 and 14 dB, respectively. Furthermore, the filter was integrated with a diplexer to clearly split the signals between 2 and 5 GHz. The maximum insertion and minimum return losses of the fabricated module were 2.2 and 14 dB at 2.4 - 2.5 GHz, and 1.6 and 19 dB at 5.15 - 5.85 GHz, respectively. The overall volume of the fabricated filter was $2.7{\times}2.3{\times}0.59mm^3$.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.3
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• pp.163-168
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• 2003

Three-dimensional solid model has not been widely used in surgical prediction of orthognathic surgery because frequent artifacts from occlusal restorations or prosthesis limited the usefulness of simulated surgery involving occlusion. We prepared three-dimensional(3D) solid model from CT data and integrated the 3D solid model with dental cast using a face-bow transfer technique combined with skeletal reference measurement and confirmation with cephalometric radiographs. With this simple and easy method, it was possible to predict bony interference between the proximal and distal segment of the mandible so that we can prevent condylar displacement after sagittal split ramus osteotomy of the mandible with prominent asymmetry. The method error was within 2mm and it seemed to be useful in preoperative planning for maxillofacial surgery with maxillo-mandibular occlusal change.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.245-252
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• 2018

In this paper, the dual band circular polarization patch antenna was designed by using band rejection characteristics of CSRR structure for geostationary satellites. A quadrangular CSRR structure was etched on the ground at the rear of the patch antenna's feed to obtain band rejection characteristics in between the receiving frequency band(1525~1559MHz) and transmission band(1626.5~1660.5MHz), and the corner of the patch antenna was truncated to enable circular polarization. It was confirmed that the resonant frequency of the patch antenna differs according to the size anc location of the CSRR and cirular polarization characteristics with simulation and measurement results. Measurement results shows the gain of about 0.2dB and 1.5dB in the TX and RX band.

• Journal of Aerospace System Engineering
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• v.2 no.1
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• pp.7-12
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• 2008

The three-dimensional finite element modeling of a composite rotor blade is very hard and requires much computation effort. The efficient method to model a composite beam is necessary for the dynamic and aeroelastic analyses of rotor blades. In this study, the beam modeling method of a composite rotor blade is studied using VABS. The computer program, VABS (Variational Asymptotic Beam Section Analysis), uses the variational asymptotic method to split a 3-D nonlinear elasticity problem into 2-D cross-sectional analysis and 1-D nonlinear beam problem. The VABS can produce the sectional stiffness coefficients of composite rotor blades with various cross section and initial twist/curvatures, and recover the original 3-D distribution of displacement/strain/stress fields. The results of various cross section beams show that VABS gives us the accurate results comparared to commercial codes and does not need much computation effort. It can be concluded that VABS provides the efficient method to establish the FE model of a composite rotor blade.

• ETRI Journal
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• v.18 no.3
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• pp.171-179
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• 1996

Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of $0.15{\mu}m$ gate length with $1.35{\mu}m-wide$ head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at $V_{ds}=2V andI_{ds}=17mA$ was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9.

• Journal of the Korean Arthroscopy Society
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• v.15 no.2
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• pp.99-107
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• 2011

Purpose: The purpose of this study was to investigate the clinical results after a anatomical double bundle ACL reconstruction using a longitudinally split tibialis anterior allograft. Materials and Methods: We evaluated 24 patients with a minimum follow-up of 12 months who had undergone anatomical double bundle ACL reconstructions. The grafts utilized in all cases were tibialis anterior allografts which were longitudinally split into two strands. A standard rehabilitation protocol was applied in all patients. The pre- and post-operative data including Lysholm scores, International Knee Documentation Committee (IKDC) scores, Lachman test, pivot shift test and the side-to-side differences of anterior laxity measured by KT-2000 arthrometer were analyzed by use of a statistical method Results: The mean side-to-side instrumented laxity measured by the KT-2000 arthrometer significantly improved to a mean of $1.04{\pm}0.80\;mm$ (P < 0.001). The Lysholm knee scores also improved from $58.34{\pm}15.32$ to $86.25{\pm}6.48$ after surgery (P < 0.001). The patients exhibited improved IKDC scores (A: 15 cases, B; 9 cases) at the final follow-up, compared to preoperative scores (B: 5, C: 10, D: 9). Conclusion: Our data demonstrated that clinical results of anatomical double bundle ACL reconstruction with a split tibialis anterior allograft are encouraging with excellent side-to side laxity, significantly improved Lysholm knee score, IKDC score, Lachman and pivot shift data.