• 농업과학연구
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• 제49권4호
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• pp.845-855
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• 2022

The purpose of this study is to develop a self-propelled underground crop harvester and its performance was evaluated by measuring the load during actual potato harvesting operations. This study was conducted at a constant working speed of 1 km·h^-1. A load measurement system was installed to measure the actual load and the required working power was analyzed. A hydraulic pressure sensor was also installed to measure the hydraulic pressure. The required hydraulic power was calculated using the hydraulic pressure and flow rate. The results showed that the engine speed, torque, and power during harvesting operation were in the range of 845 - 1,423 rpm, 95 - 228 Nm, and 9 - 31 kW, respectively. Traction power, excluding the hydraulic pump of the tractor and power take-off (PTO) output, was in the range of 9 - 28 kW, and it was confirmed that it occupies a ratio of 16.2 to 50% of the engine rated output. The engine can supply the minimum required traction power to move the vehicle. This means that the engine used in this study could be down-sized to be suitable for an underground crop harvester. In this study, the gear stages of the tractor were not considered. This research thus shows the possibility of developing a self-propelled underground crop harvester.

• 한방재활의학과학회지
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• 제18권4호
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• pp.39-61
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• 2008

목적 : 좌골신경 압좌손상으로 유발된 쥐의 모델을 이용하여 손상된 말초신경의 재생효과에 관한 침자극 효과를 세포분자학적, 조직학적 관점에서 연구하였다. 아울러 손상 좌골신경을 지배하는 척수신경근과 가까운 부위 경혈자극과 좌골신경이 지배하는 말초부위 경혈자극과의 침자극 효과를 비교 연구하였다. 방법 : 한쪽 좌골신경에 압좌손상을 유발 한 실험쥐들을 1주, 2주로 나눈 뒤 각각에 대해 격일로 1주군은 3회, 2주군은 6회의 침자극을 시행하였다. 손상 좌골신경의 재생효과를 비교실험하기 위해 정상군, 압좌손상만을 유발한 실험군, 침자극 군으로 나누었다. 침자극 군 중 한 군은 손상신경을 지배하는 척수신경근에 가장 가까운 2개의 화타협척혈(EX B2)에 자침(근위부 자극군)하였고, 다른 한 군은 말초부위에 위치한 족삼리혈(ST 36)과 위중혈(BL 40) 2곳에 자침(원위부 자극군)하였다. 실험 후 각각의 조직을 분리하여 Western blotting 혹은 Hoechst staining으로 Gap-43, Cdc2, Cdk2, Erk1/2 단백질을 분석 및 좌골신경의 각 세포수를 측정하였다. Retrograde tracing을 통해 L5의 DRG와 척수에서 말초신경 재생 효과를 관찰하였고, Immunofluorescence staining을 통해 신경돌기 가지의 신장 정도를 파악하였다. 결과 : 좌골신경 손상 7일된 실험쥐의 근위부와 원위부 침자극군에서 GAP-43와 Cdc2 단백질수준이 향상된 것으로 나타났다. Cdk2 단백질수준은 압좌손상 실험군에서 강하게 증가하였지만 침자극군과 비교해서 별다른 차이는 보이지 않았다. Phospho-Erk1/2 단백질수준은 침자극군에서 향상된 것으로 나타났다. 손상 7일과 14일 된 실험쥐의 손상 원위부에서 슈반세포 수가 증가하였으며 특히 근위부 침자극군에서 더욱 증가한 것으로 나타났다. Retrograde tracing을 이용한 검사 결과 침자극군에서 L5의 DRG와 척수의 염색 세포 수가 증가된 것으로 나타나 침자극이 축삭재생에 효과적인 것으로 나타났다. L5의 DRG 감각신경의 신경돌기 가지 신장정도 및 GAP-43 단백질의 발현 정도를 측정한 결과 근위부 침자극군에서 효과적으로 GAP-43 단백질의 발현 및 신경돌기 가지가 신장된 것으로 나타났다. 결론 : 본 실험결과 침치료가 손상 좌골신경의 재생에 효과적인 것으로 보여지며, 특히 손상된 좌골신경을 지배하는 척수신경근 주위 화타협척혈에 대한 침자극이 말초부위의 침자극에 비해 신경재생에 더욱 효과적인 것으로 나타났다.

• Corrosion Science and Technology
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• 제4권3호
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• pp.75-80
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• 2005

This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 $^{\circ}C$ and 2000~10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperaturewhilethe corrosionrate increasedwith boronconcentration. The experimental resultsobtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightlysolubleboric acid phase.Moreoverthe galvaniccorrosionrate calculatedusing initialgalvaniccoupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor.

• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.233-236
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• 2012

The driving properties of a particle-insertion method that filters non-moving particles are analyzed, by measuring its optical and electrical properties. An area that is occupied by the moved particles is proposed, as a desirable evaluation method for a reflective display. To compare the driving property of the particle-moving method with that of the reported simple particle-loading method, two panels are fabricated, according to the different particle-insertion methods, in the same panel condition, of which the width of ribs is $30{\mu}m$, the cell size is $220{\mu}m{\times}220{\mu}m$, the cell gap is $116-120{\mu}m$, the q/m value of the black particles is $+1.8{\mu}C/g$ and that for the white particles is $-4.3{\mu}C/g$. The particle-moving method has a filtering effect which excludes the non-moving particles, inserting only movable particles into the respective cell, so that a panel fabricated by the particle-moving method can drive most of the particles in a cell. Also, most of the particles move at the threshold voltage of 40 V, with enhanced reflectivity. The driving property is also verified by measurement of the occupation rate of the moved particles.

• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.634-640
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• 2009

The plate manufacturing processes are composed of the reheating furnace, finishing mill, cooling process and hot leveling. The finishing rolling mill (FM) as a reversing mill has produced the plate steel through multiple pass rolling. The automatic gauge control (AGC) is employed to maintain the thickness tolerance. The high grade products are forming greater parts of the manufacturing and customers are requiring strict thickness margin. For this reason, the advanced AGC method is required instead of the conventional AGC based on the PI control. To overcome the slow response performance of the conventional AGC and the thickness measurement delay, a fuzzy AGC based on the thickness deviation and its trend is proposed in this paper. An embedded controller with the fuzzy AGC has been developed and implemented at the plate mill in POSCO. The fuzzy AGC has dynamically controlled the roll gap in real time with the programmable logic controller (PLC). On line tests have been performed for the general and TMCP products. As the results, the thickness deviation range (maximum - minimum of the inner plate) is averagely from 0.3 to 0.1 mm over the full length. The fuzzy AGC has improved thickness deviation and completely satisfied customer needs.

• 수산해양기술연구
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• 제51권1호
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• pp.94-101
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• 2015

The heat treatment machine based on immersion was developed to reduce temperature difference during netting process and appraised it performance compared current heat treatment machine using high pressure. It was also reviewed the optimum heat treatment procedures for PBSAT monofilament net in accordance with the immersion time and temperature. The procedure was based on physical measurement such as breaking load, elongation and angle of the mesh for PBSAT monofilament. The water temperature gap of the treatment machine based on immersion was less than $1^{\circ}C$. and the energy consumption was also increased in high temperature condition. It was identified that the optimum temperature was $75^{\circ}C$ and its optimum processing time was between 15 minutes and 20 minutes to get qualified physical properties.

• ETRI Journal
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• 제37권1호
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• pp.97-106
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• 2015

In this paper, MOS-triggered silicon-controlled rectifier (SCR)-based electrostatic discharge (ESD) protection circuits for mobile application in 3.3 V I/O and SCR-based ESD protection circuits with floating N+/P+ diffusion regions for inverter and light-emitting diode driver applications in 20 V power clamps were designed. The breakdown voltage is induced by a grounded-gate NMOS (ggNMOS) in the MOS-triggered SCR-based ESD protection circuit for 3.3 V I/O. This lowers the breakdown voltage of the SCR by providing a trigger current to the P-well of the SCR. However, the operation resistance is increased compared to SCR, because additional diffusion regions increase the overall resistance of the protection circuit. To overcome this problem, the number of ggNMOS fingers was increased. The ESD protection circuit for the power clamp application at 20 V had a breakdown voltage of 23 V; the product of a high holding voltage by the N+/P+ floating diffusion region. The trigger voltage was improved by the partial insertion of a P-body to narrow the gap between the trigger and holding voltages. The ESD protection circuits for low- and high-voltage applications were designed using $0.18{\mu}m$ Bipolar-CMOS-DMOS technology, with $100{\mu}m$ width. Electrical characteristics and robustness are analyzed by a transmission line pulse measurement and an ESD pulse generator (ESS-6008).

• East Asian mathematical journal
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• 제33권2호
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• pp.177-197
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• 2017

The purpose of this study is to investigate and analyze the understandings of elementary pre-service teachers about 'estimation' in the elementary mathematics. Together with this analysis, we identify elementary pre-service teacher's Mathematical Pedagogical Contents Knowledge(MPCK), especially focusing to Subject Matter Knowledge(SMK). In order to this goals, we investigate contents relating to 'estimation' from $1^{st}$ curriculum to 2009 revised curriculum and compare 'rounding up', 'rounding off', 'rounding' in the elementary mathematics textbooks. As results of investigations, 'estimation' has been teaching at the 'Measurement' domain from $3^{rd}$ curriculum, but contexts of measuring weaken from $7^{th}$ curriculum. 'Rounding up(off)' is defined three types in the textbooks from $1^{st}$ to 2009 revised curriculum. And we examine elementary pre-service teachers through the questions on these 'estimation' contents. On the analysis of pre-service teacher's understanding relating MPCK, four themes is summarized as followings; the understanding of '0' in the 'rounding up', the cognitive gap between 'rounding up' and 'rounding off', the difference of percentage of correct answers according to types of question in the 'rounding up', and the difference between the definition of 'rounding up' and the definition of 'rounding'.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.515-517
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• 2004

The laser absorption spectroscopy has been used for measuresurement of the xenon atoms in the resonant $1S_4$ and metastable $1S_5$ states in coplanar AC PDP. For the purpose of improving VUV luminous efficiency and optimization of PDP cells, it is important to study behavior of excited Xe atoms in a micro-discharge cell of a coplanar AC-PDP. We measured the xenon excited density of $1S_5$ and $1S_4$ state under mixture gas of Ne-Xe(10%) with gas pressure of 350 Torr and sustaining gap distance of 150 um.

• 전기학회논문지P
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• 제55권1호
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• pp.26-30
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• 2006

For the purpose of developing capacitive humidity sensor having interdigital electrodes, interdigital electrode was modeled and simulated to obtain capacitance and sensitivity as a function of geometric parameters like the structural gap and thickness. For the development of ASIC, switched capacitor signal processing circuits for capacitive humidity sensor were designed and simulated by Cadence using $0.25{\mu}m$ CMOS process parameters. The signal processing circuits are composed of amplifier for voltage gain control, and clock generator for sensor driving and switch control. The characteristics of the fabricated sensors are; 1) sensitivity is 9fF/%R.H., 2) temperature coefficient of offset(TCO) is $0.4%R.H./^{\circ}C$, 3) nonlinearity is 1.2%FS, 4) hysteresis is 1.5%FS in humidity range of $3%R.H.{\sim}98%R.H.$. The response time is 50 seconds in adsorption and 70 seconds in desorption. Fabricated process used in this capacitive humidity sensor having interdigital electrode are just as similar as conventional IC process technology. Therefore this can be easily mass produced with low cost, simple circuit and utilized in many applications for both industrial and environmental measurement and control system, such as monitoring system of environment, automobile, displayer, IC process room, and laboratory etc.