• Carbon letters
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• 제12권1호
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• pp.26-30
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• 2011

For polyacrylonitrile (PAN) based carbon fiber (CF) process, we developed a lab scale wet spinning line and a continuous tailor-made stabilization system with ten columns for controlling temperature profile. PAN precursor was spun with a different spinning rate. PAN spun fibers were stabilized with a total duration of 45 to 110 min at a given temperature profile. Furthermore, a stabilization temperature profile was varied with the last column temperature from 230 to $275^{\circ}C$. Stabilized fibers were carbonized in nitrogen atmosphere at $1200^{\circ}C$ in a furnace. Morphologies of spun and CFs were observed using optical and scanning electron microscopy, respectively. Tensile properties of resulting CFs were measured. The results revealed that process conditions such as spinning rate, stabilization time, and temperature profile affect microstructure and tensile properties of CFs significantly.

• 한국염색가공학회지
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• 제35권2호
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• pp.121-127
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• 2023

In this study, a comprehensive investigation was conducted on the morphological and property changes of laser-induced nanocarbon (LINC) as a function of laser process parameters. LINC was formed on the surfaces of polyimide films with different backbone structures under various process conditions, including laser power, scan speed, and resolution. Three different forms of LINC electrodes (i.e., continuous 3D porous graphene, wooly nanocarbon fibers, line cut) were formed depending on the laser power and scan speed. Furthermore, heteroatom doping induced from the chemical structure of the polyimide during laser patterning was found to be effective in modifying the electrical properties of LINC electrodes. The LINC surfaces exhibited different microstructures depending on the laser beam resolution under constant laser power and scan speed, allowing for controllable surface wettability. The correlation between the chemical structure of the polymer substrate, laser process parameters, and carbonized surface properties in this study is expected to be utilized as fundamental understanding for the manufacturing of next-generation carbon-based electronic devices.

• Journal of the Korean Wood Science and Technology
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• 제52권3호
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• pp.276-288
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• 2024

This study was conducted to reproduce the woodworking process of Baekje wooden storage facilities. Green timber of Quercus spp. was processed using ancient woodworking tools, and the tool-trace formed in this process were compared with the tool-trace of actual excavated artifacts. In the tool-trace analysis, the length and shape of the tool-trace were objectively recorded using a 3D Scan, and that were difficult to confirm with photograph were confirmed through stereoscopic microscope. As a result, there were two types of adze's tool-trace. One of them is minute straight Blade-top trace line when trimming the wood surface and the other is Plucked trace that appear when strongly chop at the wood. When a chisel bat was not used, a long and wide continuous shape blade trace was produced. And when the chisel head was struck with the chisel bat, a straight blade-top trace was regularly observed. Saw-trace was identified in several layers with fine straight stripes. Through this, it was found that the tool-trace of the woodworking tools, which is estimated to have been used in each process, and the tool-trace remaining in the Baekje wooden storage facility coincide.

• 분석과학
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• 제21권5호
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• pp.345-363
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• 2008

이미 석유화학산업 등 대규모 산업공정에서 널리 활용되고 있는 공정분석화학 및 공정분석기술의 역사는 오래되었지만, 최근 "공정분석기술(Process Analytical Technology: PAT)"의 새로운 개념이 매우 빠르게 일부 산업분야의 생산공정에 보급되고 있다. 본 총설에서는 이미 오래 전부터 대규모 연속식 생산라인에서 널리 활용되어 왔던 공정분석화학 및 공정분석기술의 신개념 첨단 분석기술로서의 태동 배경과 용어 정의 등을 명확히 하였다. 또한, 공정최적화를 위한 공정분석화학 혹은 공정분석기술의 기본개념, 계량화학 등의 공정분석화학 핵심요소, 국내외 산/학/연의 기술 및 활동 현황 등에 관하여 다루었고, PAT에서 주로 활용되고 있는 공정분석기기의 종류와 현황, 그리고 미래 유망기술 및 활용분야에 대해서도 소개하였다.

• 간호행정학회지
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• 제6권1호
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• pp.123-134
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• 2000

This study intended to analyze the effectiveness to obtain by developing the critical pathway presented as the method to improve the quality-betterment and cost effectiveness the through the continuous and consistent patient management for the hysterectomy patient and applying it to the real practice. This study was designed to develop and effect the critical pathway for hysterectomy patients in the way to be possible the intergrated in patient management. It was adopted the process of seven phase to develop a critical pathway. To analyze the application effect of the developed critical pathway, this author offered health care service applying the critical pathway to the hysterectomy patient from July. 20 to Oct. 19. 1999. The study method had been done by investigating the experimental group and control group through the questionnaire on 40 patients who had been inpatient hysterectomy. Dependent variables were measured by modified from satisfaction, and cost and length of hospital stay. The data anlyzed by frequency, x2-test, t-test. The results of this study was as follows; 1. It was decided that the vertical line of the critical pathway was made up of eight items such as monitoring/assessment, treatment, activity, medication, consult. Lab test, diet, patient teaching and horizontal line was 7days from admission to discharge. 2. After the verifying the validity of the expert group about the critical pathway, the horizontal line was amended from hospitalization to five postoperative days and taking their consensus, some contents of the horizontal line was amended and deleted. 3. There was no significant differences in the experimental group and control group in the satisfaction, and significant differences in the cost, the length of hospital stay.

• 한국안전학회지
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• 제14권2호
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• pp.70-76
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• 1999

In this paper, a mixed-integer programming approach is presented for adjusting the voltage profiles in a power system. The advent of large-scaled system makes the reactive power and voltage problem-an attempt to achieve an overall improvement of system security, service quality and economy-more complex and seriously, Although the problem is originally a nonlinear optimization problem, it can be formulated as a mixed integer linear programming(MILP) problem without deteriorating of solution accuracy to a certain extent. The MILP code is developed by the branch and bound process search for the optimal solution. The variable for modeling transformer tap positions is handled as discrete one, and other variables continuous ones. Numerical data resulting from case study using a modified IEEE 30 bus system with outaged line show that the MILP can produce more reductions of magnitude in the operating cost. The convergence characteristics of the results are also presented and discussed.

• 상하수도학회지
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• 제24권3호
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• pp.333-339
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• 2010

Particle removal is an important step taken at water treatment plants (WTPs) for the safety of tap water due to its proportionality to the pathogen inactivation. Government promulgated a treatment technique for the optimization of filtration including continuous turbidity monitoring using on-line turbidimeters. Based on the turbidity measurements of 460 filters at 31 WTPs operated by K-water, the evaluation of filtration performance and the investigation of major causes related to particle breakthrough were explored. 98.1 % of the filters had an effluent turbidity measurement which was less than 0.1 NTU, but turbidity breakthrough of more than 0.3 NTU was noticed occasionally which is in violation of AWWA 5-Star guidelines. It was shown that the optimization of coagulation, filter-to-waste, the observance of optimal filtration velocity and backwashing process based on filtrate turbidity were crucial for the improvement of filtrate.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1488-1491
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• 1996

Throughout CGL(Continuous Galvanizing Line) in steel works, zinc-coated steel sheets are produced which are used where long-running corrosion resistivity is required. During the galvanizing process, top dross is created and floated on the zinc pot. Because the dross leaves ill patterns on the coated sheets, it is removed manually with shovel-like tools in about twenty minutes. Because, however, the working environment is very noisy, hot and harmful to human workers, a robot system is developed and implemented on a real plant to automatically remove the top dross. It consists of a robot and its carriage system, a pot level sensor, a system controller, and special tools to collect, pick up, and put the top dross into a dross waste basket. A system software is developed to monitor the system status. A series of tests were performed to verify the robot motion and adaptation to working conditions, and proved successful work.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.836-839
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• 1996

Throughout CGL (Continuous Galvanizing Line) in steel works, zinc-coated steel sheets are produced which are used where long-running corrosion resistivity is required. During the galvanizing process, top dross is created and floated on the zinc pot. Because the dross leaves ill patterns on the coated sheets, a robot system is developed to automatically collect and remove the top dross. It consists of a robot and its carriage system, a pot level sensor, a system controller, and special robot tools. For the first time the level of zinc pot must be measured and fed back to the robot controller to avoid submersion of the robot hand into the hot zinc pot. In this paper, acoustic distance sensor is tested as a candidate for the pot level sensor in the view point of hot environment. Some considerations on the use of the acoustic distance sensor will be denoted.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.323-327
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• 1995

A new air knife system for coating thickness control in hot dip galvanizing process had been developed and installed on the CGL in Pohang Steel Works, POSCO. This new system consists of air knives with remotely adjustable nozzle slot and an automatic control system which can control both longitudinal and traverse coating deviations. Based on the optimal control algorithm, a traverse coating deviation control was designed. The controller controls the lip profile of the air knives with flexible structure according to the deviation of coating weight. From the measured values which are dependent on the strip width, the lip gaps are calculated with optimal algorithm and the model of the coating deviation. Time delay between knives and a coating thickness gauge is solved by the Smith Predictor.