• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.4
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• pp.81-90
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• 2020

A textile and capillary tube composite panel(TCP) was developed to simultaneously retrofit the seismic performance and the energy efficiency (e.g. heating or insulation performance) of existing unreinforced masonry (URM) buildings. TCP is a light-weight mortar panel in which carbon textile reinforcements and capillary tubes are embedded. Textile reinforcements plays a role of seismic retrofit and capillary tubes that hot water circulates contribute to the energy retrofit. In this paper, the static cyclic loading tests were performed on the masonry walls with/without TCP to understand the seismic retrofit effect of TCP retrofit and the results were summarized. The results of the test showed that the TCP contributed to increase the capacity of the Shear strength and ductility of the URM walls. In addition, the deformation of the wall after cracking was substantially controlled by the carbon textile.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.454-461
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• 2003

This study addressed a procedure to carry out an experimental study on a behavior of simple and continuous concrete beams. For this purpose, sample concrete beams were fabricated and sensors for the measurement of strains and deflections were attached both on the surface of the beams and inside them. Two types of sensors were used to measure strains associated with loading: electric resistance strain sensors and fiber optic sensors. Displacement gauges were also attached on the bottoms of beams to investigate the behavior of beams more rationally. The behavior of the beams was then evaluated throughout the results measured from different sensors while they were subject to steady loading up to failure. From results of this study, it was found that concurrent use of sensors and displacement gauges is helpful in investigating the behavior of concrete beams more effectively. Especially, combined-type strain sensors specifically fabricated in this experiment were found not to be affected by the occurrence of cracks so significantly and to be very effective in monitoring strains of concrete structure. It was also observed that beams show nonlinear force-displacement relationship and reinforcing bars take charge of resisting the external force once cracks occur in concrete beams.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.917-920
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• 2008

ECC is a special kind of high performance cementititous composite which exhibits typically more than 2% tensile strain capacity by bridging microcracks at a crack section. Therefore, micromechanics should be adopted to obtain multiple cracking and strain hardening behavior. This paper propose a linear elastic analysis method to simulate the multiple cracking and strain hardening behavior of ECC. In an analysis, the stress-crack opening relation modified considering the orientation of fibers and the number of effective fibers is adopted. Furthermore, to account for uncertainty of materials and interface between materials, the randomness is assigned to the tensile strength(${\sigma}_{fci}$), elastic modulus($E_{ci}$), peak bridging stress(${\sigma}_{Bi}$) and crack opening at peak bridging stress(${\delta}_{Bi}$), initial stress at a crack section due to chemical bonding, (${\sigma}_{0i}$), and crack spacing(${\alpha}_cX_d$). Test results shows the number of cracking and stiffness of cracked section are important parameters and strain hardening behavior and maximum strain capacity can be simulated using the proposed method.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.415-420
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• 2005

LMTT (Linear Motor-based Transfer Technology) is the horizontal transfer system for yard automation, which has been proposed to take the place of AGV (Automated Guided Vehicle) in the maritime container terminal. The system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that consists of stator modules on the rail and shuttle car. It is desirable to reduce the weight of LMTT in order to control the electronic devices with minimum energy. In this research, structural optimization for a mover of shuttle car is performed to minimize the weight satisfying design criteria. The objective function is set up as weight. On the contrary, the design variables are transverse, longitudinal and wheel beams' thicknesses and its height, and the constraints are considered as strength and stiffness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1505-1512
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• 2007

The RFID Technology (which is importantly used at the Ubiquitous environment) is attached to all of the units like the ID cards and then information on the units and units' environment is transferred and processed through the radio frequency. so it is the no touched recognition system. RFID Technology's research of the middle ware and wireless interface etc. is currently conducted and variously broaden like the industry of the distribution and logistics. This paper suggests that the gate control system which is based on RFID middle ware is realized to prevent the district and facility for security. The indication of this paper is that algorithm (which is to certificate Users' enterance through RFID EPC code) is proposed and realizes the user certification module, the control module of the gates' opening and closing, the maintenance module of the gate, the display module of coming and going information, test program ect. through RFID technology.

• Analytical Science and Technology
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• v.7 no.4
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• pp.483-492
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• 1994

Direct solid analysis of various kinds of metal samples has been conducted by glow discharge. In this laboratory, the gas-jet assisted glow discharge(GJGD) device has been developed and characterized. The effect of changes in applied current, cell pressure and flow rate on atomic emission signals obtained from a jet-assisted cathodic sputtering was investigate. The emission intensities of Cu, Zn, and Ar were measured. They were increased with the current. But the intensities were decreased by increasing the flow rate of argon due to the diffusion and transportation of particles into plasma. By increasing the pressure of the cell, the intensities were greatly decreased because of enhancement of redeposition onto the surface of the sample.

• Journal of Surface Science and Engineering
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• v.11 no.1
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• pp.5-13
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• 1978

This experiment intends to study Zn-coating weight through galvanixing process. A through examination has been carried out on the change of steel-composition, galvanizing-temperature, dipping-rime, Fe-loss when other factors were regular. Activation energy needed for Fe-loss was obtained and within this sample, the best condition which has influence on coating weight was found so as to reduce Fe-loss. As Fe-loss was diminidhed, the amount of product of Dross and Zn-using amount per total products could be reduced. The results of experiments are as follow. 1. Zn-coating thickness was increased by the rising Zn-bathtemperature and was the maximum at 8-minutes dipping time. 2. The coating weight was greatly influency by Si. As in other samples, the proportion of increasing was very rate after 20minutes. If the dipping time prolonged, the increasing amounts of Fe-loss are more greatly. 3. Activation Energy needed for Fe-loss was as follows Such numerical values were most equal to those of the activation energy which had influences on the growth of ${\gamma}$-phase. Sample - I = 18,500 Cal/mole Sample - III = 22,000 Cal/mole Sample - V = 42,300 Cal/mole

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.330-331
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• 2005

본 논문에서는 카메라폰용 광학중(Optical zooming) 과 자동초점조절장치 (Auto Focusing, AF)에 쓰일 초음파모터를 제작하였다. 초음파모터의제작 및 시뮬레이션은 유한요소해석 프로그램인 ATILA 5.2.1 (Magsoft co.)를 사용하여 디자인설계에 따른 구동특성을 고찰하였고 제작된 초음파모터는 한쪽 면이 없는 사작형의 탄성체를 제작하였으며 탄성체의 양쪽 다리에 각각 압전체를 부착하였다. 또한 압전세라믹의 조성은 $0.9Pb(Zr_{0.51}Ti_{0.49})O_3-0.1Pb(Mn_{1/3}Nb_{1/3}Sb_{1/3})O_3$의 조성으로 설계하였고 시편의 제조는 7-layer로 적층하였다. 제작된 압전세라믹의 치수는 6*2*0.35$mm^3$(길이*폭*두께)로 제작하였다 또한 탄성체의 외형치수는 10*10*2$mm^3$로 제작하였으며 두께를 각각 0.3[mm], 0.5[mm], 0.8[mm]으로 변화시키며 제작하였다. 두께가 0.8[mm]인경우 공진주파수는 60.5[kHz]를 나타내었으며 초음파모터의 압전세라믹에 인가전압이 증가함에 따라 회전속도와 모터에 흐르는 전류는 증가하였다. 인가전압이 40[Vpp] 일 때 회전속도는 206[rpm] 이며 소비전력은 0.3[W]로 제작된 시편은 카메라폰용 광학중 및 자동초점조절장치시스템 분야에 응용이 가능하다.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1425-1433
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• 2011

We investigated an early rehabilitation training system that increase the intensity of patient rehabilitation training to shorten the time it takes for patients to progress to a secondary rehabilitation training stage by allowing patients incapable of self-ambulation. It consisted of tilting bed, unstable platform using strong springs and training program for lower limb rehabilitation. We performed experimental study on the muscular activities of tibialis anterior(TA), soleus(SO), gastrocnemius(GA) in the lower extremities during training of straight line, circle, quardrangle pattern during tilting angle of $30^{\circ}$, $60^{\circ}$. The muscle activities were higher during tilting angle of $30^{\circ}$ than $60^{\circ}$. In straight line pattern, the muscle activities were higher by SO, GA and TA during medio-lateral direction, however, by TA, SO and GA during anterio-posterior direction. In circle and quardrangle pattern, the muscle activities were higher by TA, SO and GA during clockwise and counterclockwise direction. The results indicate that the early rehabilitation training system could be applied to improve the lower extremity muscular strength for elderly and patients, especially, stroke.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.43-43
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• 2018

수생태계는 다른 여러 생태계 중에서 가장 위험에 처해있으며, 기후변화로 인한 수온, 수문 수질의 변화는 수생태계와 담수 생물다양성에 가장 큰 영향을 미치는 요인 중 하나이다. 본 연구에서는 생물 생태학적으로 변화하는 세계적인 물 관리 패러다임에 따라 한강유역에서의 미래 수생태계 평가를 수행하였다. 본 연구의 목적은 수생태 건강성 관측자료와 수질자료, SWAT 모형을 이용하여 미래 기후변화에 따른 한강유역의 수생태를 평가하는 것이다. 본 연구에서 선정한 수생태계 건강성 조사자료로 국립환경과학원에서 8년간(2008년~2015년) 봄과 가을 2차례에 걸쳐 모니터링 한 부착돌말류(TDI), 저서형 대형무척추동물(BMI), 어류(FAI)에 대한 수생태 등급자료 및 해당 지점에 대한 수온 및 수질자료를 이용하였다. 수집한 결과를 DB(T-N, $NH_4N$, $NO_3N$, T-P, PO4P)에 대한 수생태 등급의 상관성을 분석하고 수온 수질인자에 따른 수생태 등급을 나타내어 미래 기후변화에 따른 수생태 건강성 평가 및 예측을 실시하고자 하였다. Soil and Water Assessment Tool (SWAT) 모형은 유역의 신뢰성 있는 유역 수문, 수질 모의 및 기후변화 영향평가를 위하여 활용되었다. SWAT 모형을 이용하여 한강유역의 다목적댐(3개), 발전용댐(1개), 다기능보(3개) 운영을 고려하였고, 237개의 표준유역으로 분할한 뒤 수문 및 수질 모의를 수행하였다. 모형의 적용성 평가를 위해 댐 및 보의 유입량, 증발산량, 토양수분, 지하수위, SS, T-N, T-P에 대하여 보정(2005~2009) 및 검증(2010~2015)을 수행하였다. 기후변화에 따른 수문, 수질 및 수생태 평가를 위해 기상청의 HadGEM3-RA RCP 4.5와 8.5 시나리오를 적용하였으며, 기준년(1975-2005)년에 대해 2020s(2010-2039), 2050s(2040-2069), 2080s(2070-2099)의 수생태를 평가하였다.