• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.3
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• pp.257-264
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• 2010

In order to improve the breaking strength and elongation of Polybutylene succinate (PBS) monofilament, the monofilament was produced by blending PBS and Polybutlyne adipate-co-terephthalate (PBAT). The PBS/PBAT blend monofilament was prepared by the melt spinning system, and the weight ratios of the compositions of PBS/PBAT was 100/0, 95/5, 90/10 and 85/15, respectively. The breaking strength, elongation, softness and crystallization of PBS/PBAT blend monofilament were analyzed by using a tensionmeter, softness measurement, X-ray diffractometer in the both dry and wet conditions. The PBS/PBAT blend monofilaments were spun in the take-up velocity of 1.19m/sec under the drawing ratio of 6.8:1 condition. The production volumes of PBS/PBAT blend monofilaments showed 20% less than that of Nylon. The breaking strength of PBS/PBAT blend monofilaments were decreased as PBAT contents increased, while elongation and softness were increased. In case of PBAT content were over 5%, the breaking strength, elongation and softness of PBS/PBAT blend monofilaments were not shown to increase in spite of increasing in PBAT contents. Based on these results, it was possible to make the monofilaments with the maximized physical properties when the PBAT contents at 5%.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.1-8
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• 1989

Ten cultivars of malting barley grown at four locations were malted and assayed for six enzymes involved in the degradation of nucleic acids. Among these enzymes were deoxyrinonuclease, ribonuclease, phosphodiesterase, 3'- and 5'- nucleotidases and phosphomonesterase. Activities of all enzymes in five-day malts were significantly affected by variety and location of growth. The average levels of ribonuclease, deoxyribonuclease, 3'-nucleotidase and 5'-nucleotidase of 80 five-day malts were 11.2, 5.7, 5.6 and 1.2 units per gram of malt, respectively. Six-rowed barley malts contained higher levels of deoxyribonuclease, phosphodiesterase and 3'-nucleotidase than those of two-rowed barley malts, while two-rowed barley malts contained significantly higher ribonuclease levels than those of six-rowed barley malts.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.561-569
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• 2017

In this study, a synthetic amine made using the ethylene oxide-ammonia reaction was used as an absorbent to remove carbon dioxide. Existing absorbents were used in a mix in order to improve performance; however, because the ethylene oxide-ammonia reaction generates primary, secondary, and tertiary amines simultaneously, it has the merit that separate mixing of the absorbents was not needed. The performance of carbon dioxide absorption with the synthetic amine was compared to that of MEA. As a result of an experiment, it was determined that the $CO_2$ loading was 1.15 times better than that of MEA (a commonly used amine), while the cyclic capacity was 2.28 times higher. Because the heat of reaction was 1.10 times lower than for MEA, the synthetic amine showed superior performance in terms of absorption and regeneration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1233-1241
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• 2008

We design, fabricate, and measure a MIMO antenna system mountable on a small PCB (such as UMPC). The proposed antenna system accommodates three radiation elements on the PCB area of $40mm\;{\times}\;100mm$. Two of them employ a slot type and one uses a modified monopole with an inverted L shape expecting high isolation and polarization purity. The bandwidth of each proposed MIMO antenna ranges from 80MHz and 200MHz at the center frequency of 1.8 GHz. The isolations between ports have been found to be greater than 10dB over the interested frequency band. Besides, the proposed MIMO system has been evaluated in terms of ARC(Active Reflection Coefficient, TARC(Total ARC), correlation, MEG, and etc. The envelope correlation is calculated to be much less than 0.04 and the ratio of the mean effective gain(MEG) between the antennas is found to be close to unity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.579-584
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• 2014

In this paper, we propose beamsapce MIMO(mulitple input multiple output) system using patch ESPAR(Electronically Steerable Parasitic Array Radiator) antenna. When using conventional monopole ESPAR antenna, we have advantages cost of hardware and power consumption of RF cirsuit because of single RF chian. But it is difficult to apply to small portable mobile device. Therefore we design patch ESPAR antenna in order to reducing volume and analyze performance of BS MIMO system that is able to MIMO communication with single RF chain. In This paper, we confirm beam pattern of designed patch ESPAR antenna is steered as ${\pm}15^{\circ}$ elevation angle. Furthermore, we design BS MIMO system using this ESPAR antenna and confirm BER performance of this system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.288-297
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• 2007

The novel internal monopole chip antenna of penta-band operation for GSM850/GSM900/DCS/USPCS/WCDMA bands for mobile phones is proposed. This antenna occupies a small volume $8\times3.2\times20mm^3$ and is suitable to be embedded in a mobile phone as an internal antenna. The minimization of the proposed antenna was realized by using spiral line structure and meander line structure on FR-4 of dielectric$(\varepsilon_r=4.4)$. The designed antenna has the wide-band operation in the upper band by overlapping high order resonances. The measured bandwidth of this antenna (VSWR>3) is 150MHz$(1,030\sim1,180\;MHz)$ in the lower band operation and 650 MHz$(1,760\sim2,410\;MHz)$ in higher band operation. The measured radiation efficiency within bandwidth(VSWR 3:1) is over 50 %. The antenna has been designed by a commercial software HFSS.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.15-22
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• 2018

In this paper, a microstrip-fed triple-band monopole antenna for WLAN/WiMAX applications was proposed. The proposed antenna is consist of two arc-shaped and one strip line structure, then get the three current path and then designed in order to get triple resonant characteristics. We carried out simulation about parameters. Taking account of coupling effect, Adjusted the length of the two arc-shaped and one strip line, we get the optimized parameters. The proposed antenna is fabricated on an FR-4 substrate, the dielectric constant is 4.4, and total size is $23.5mm(W1){\times}32.0mm(L1){\times}1.0mm(t)$, and its proposed antenna size is $21.0mm(W6){\times}31.0mm(L7)$. From the measured results, return loss of the proposed antenna satisfied return loss 927 MHz (1.844~2.771 GHz), 926 MHz (3.33~4.256 GHz), and 1,415 MHz (5.13~6.545 GHz). And measured results of gain and radiation patterns displayed for operating bands.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.10
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• pp.833-838
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• 2016

This paper presents a performance evaluation of various feature-initialization algorithms for forward-viewing mono-camera based simultaneous localization and mapping (SLAM), specifically in indoor environments. For mono-camera based SLAM, the position of feature points cannot be known from a single view; therefore, it should be estimated from a feature initialization method using multiple viewpoint measurements. The accuracy of the feature initialization method directly affects the accuracy of the SLAM system. In this study, four different feature initialization algorithms are evaluated in simulations, including linear triangulation; depth parameterized, linear triangulation; weighted nearest point triangulation; and particle filter based depth estimation algorithms. In the simulation, the virtual feature positions are estimated when the virtual robot, containing a virtual forward-viewing mono-camera, moves forward. The results show that the linear triangulation method provides the best results in terms of feature-position estimation accuracy and computational speed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.114-122
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• 2014

For an efficient finite-difference time-domain(FDTD) analysis of coaxial-probe feeding structures in radio frequency(RF) and microwave bands, an interrelation between equivalent source modeling techniques is investigated. In existing literature, equivalent source models with delta-gap or magnetic-frill concepts have been developed by many researchers. It is well known that FDTD implementation and computational accuracy of these source models are slightly different. In this paper, the interrelation between FDTD equivalent source models for coaxial feeding structures under the quasi-static approximation(QSA) is presented. As a function of FDTD equivalent source models, time-domain and frequency-domain responses of a coaxial-probe fed conical monopole antenna are calculated numerically. And comparison results of computational accuracy and efficiency are provided.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.99-107
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• 2014

Abruptly occurred obstacles on highway threaten driving safety. Radar draws the attention to the collision avoidance system because it can be fully operational in all weather, and day and night condition. This paper presents the design, implementation and performance test results of pulsed Doppler radar system for detection and warning of road obstacles. The system is designed to consider highway environment and detection capability about various fixed and moving obstacles. The system consists of 4 subsystems, which include antenna unit, transmitter and receiver unit, radar signal & data processing unit, and controller & display unit. The core technologies include clutter map based change detection for fixed obstacles detection, Doppler estimation for velocity detection of moving targets, and azimuth angle estimation method using monopulse for lane estimation and tracking. The design performance of the developed radar system is verified through experiments using a fixed reference target and moving vehicles in test highway.