• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1942-1947
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• 2007

A thermoelectric module can be used for cooling or power generation. The basic requirements to achieve a significant thermoelectric performance are the same for both generators and coolers. Thermoelectric modules with $Bi_2Te_3$ materials are usually employed in the cooling applications below room temperature but it can also be used for the power generation in the similar temperature range. In the present study, the power generation with a $Bi_2Te_3$ thermoelectric module has been investigated. The temperature difference between the hot and cold sides of the module is maintained with electric heater and cold water from the circulating water bath. The result shows that the electric current generated increases with temperature difference and decreases with the load resistance. However, the voltage increases with both the temperature difference and load resistance. The electric power increases with temperature difference and it has the maximum value when the load resistance is about 4 ${\Omega}$ for a given device.

• 한국산업융합학회 논문집
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• 제5권1호
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• pp.11-19
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• 2002

This study described computer aided die design system for cold forging of non-axisymmetric parts such as gears and splines. To design the cold forging die, an integrated approach based on a rule-base system and commercial F. E. code were adopted. This system is implemented on the personal computer and its environment is a commercial CAD package named as Auto CAD. The system includes four modules. In the initial data input module, variables which are necessary to design of die are inputted by user and die material are selected from the database according to the variables. In the analysis and redesign module, stress distribution acting on the designed die is analyzed by commercial FEM code NISA II with elastic mode. If die failure predicted, the designed die would modified in four ways to prevent die failure in both states of stress free and pressurizing. The developed system provides useful date and powerful capabilities for die design of non-axisymmetric parts.

• Advances in Energy Research
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• 제4권1호
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• pp.1-28
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• 2016

A grid-connected photovoltaic (PV) system comprised of multicrystalline silicon (mc-Si) modules was installed in a cold climate region in the U.S. This roof-mounted stationary PV system is a real-world application of PV for building energy generation in International Energy Conservation Code (IECC) Climate Zone 5 (and possibly similar climate zones such as 6, 7 and 8), and it served the purposes of research, demonstration, and education. The importance of this work is highlighted by the fact that there has been less emphasis on solar PV system in this region of the U.S. because of climate and latitude challenges. The system is equipped with an extensive data acquisition system capable of collecting performance and meteorological data while visually displaying real-time and historical data through an interactive online interface. Experimental data was collected and analyzed for the system over a one-year period with the focus of the study being on measurements of power production, energy generation, and efficiency. The annual average daily solar insolation incident upon the array was found to be $4.37kWh/m^2$. During the first year of operation, the PV system provided 5,801 kWh (1,264 kWh/kWp) of usable AC electrical energy, and it was found to operate at an annual average conversion efficiency and PR of 10.6 percent and 0.79, respectively. The annual average DC to AC conversion efficiency of the inverter was found to be 94 percent.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.774-777
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• 2001

This paper describes a research work of developing a computer-aided design system of cold forging products. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plastic theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoCAD with a personal computer and is composed of six modules, which are selection of billet material, input of final product, process planning design, preform modification, insert design, shrink rings design module. Based on knowledge-based rules, the system is designed by considering several factors such as volume constancy, limite of formability by material, preform shape and so on.

• 한국정밀공학회지
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• 제13권4호
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• pp.43-52
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• 1996

This paper describes interactive computer procedures for design the forming sequences in cold forging. This system is implemented on the personal computer and its environment is a commercial AutoCAD system. The programming language. AutoLISP, was used for the configuration of the system. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the part is a key in process planning. To recognize the part section geometry, the section entity representation, the section coordinate-redius representation and the section primitive geometru were adopted. This system includes six major modules such as input module, forging design module, forming sequence design module, die design module, FEM verification module and output module which are used independently or in all. The sequence drawing wigh all dimensions, which includes the dimensional tolerances and the proper sequence of operations, can generate under the environment of AutoCAD. The acceptable forming sequences can be verified further, using the FE simulation.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.55-59
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• 2021

A thermoelectric cooler (TEC) is promising as an alternative refrigeration technology for the sake of its inherent advantages; no-moving parts and refrigerant-free in its operation. Due to the compactness, reliability and excellence in temperature stability, TECs have been widely used for small cooling devices. In recent years, thermoelectric devices have been attractive technologies that not only serve the needs of cooling and heating applications but also meet the demand for energy by recycling waste heat. In this research paper, multistage TEC is proposed as a concept of demonstrating the idea of transient cooling technology. The key idea of transient cooling is to harnesses the thermal mass installed at the interfacial level of the stages. By storing heat temporally at the thermal mass, the multistage TEC can readily reach lower temperatures than that by a steady-state operation. The multistage TEC consists of four different sizes of thermoelectric modules and they are operated with an optimized current. Once the cold-part of the uppermost stage is reached at the no-load temperature, the current is successively supplied to the lower stages with a certain time interval; 25, 50 and 75 seconds. The results show the temperatures that can be ultimately reached at the cold-side of the lowermost stage are 197, 182 and 237 K, respectively. It can be concluded that the timing or total amount of the current fed to each thermoelectric module is the key parameter to determine the no-load temperature.

• 한국한의학연구원논문집
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• 제11권1호
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• pp.109-118
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• 2005

In a field of oriental medicine, it is necessary to collect systemically clinical data and integrate. Input data items was decided, then categorized by the modules through discussion of the institute and hospitals. Items are information of patient, history, aspects of occurrence, pattern identification, prescriptions of herbal medicine, the results of biochemical serum examination, blood cell count, urine analysis, CT, MRI, Chest PA, EKG etc. Factors in oriental medicine are Sasang constitution, Stroke-Pattern-Identification(china), differentiation of cold and heat syndrome. This tool was constructed by using Microsoft-Access 2000 and Microsoft Visual Basic 6.0. Furthermore this web-based system could be applied to multi-center clinical investigation.

• 한국정보통신학회논문지
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• 제17권4호
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• pp.959-964
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• 2013

본 논문에서는 스완-간즈 카테터(Swan-Ganz catheter)를 사용하여 심장질환 중환자의 상태를 정확하게 파악하기 위해 기존의 모듈들보다 더 정밀한 데이터 측정이 가능한 모듈을 구현한다. 기존 방식은 차가운 수액을 심장에 주입하여 혈액의 온도변화와 회복시간을 측정하는 CO(Cardiac Output)를 측정하던 Bolus타입의 CO모듈이 존재하였지만, 지속적 환자 징후 관찰이 어렵다는 한계 때문에 현재는 대부분의 병원에서 사용하지 않는 상태이다. 이러한 한계를 극복하기 위해 지속적 심박출량 측정 플랫폼을 통해 효율적인 환자 징후관찰 및 상태파악이 가능 하도록 한다. 또한, 현재 기존 병원에서 심폐기능 이상 중환자의 징후관찰 및 상태파악을 위해 고가의 해외기기 도입으로 낭비되는 비용 문제를 해결하고 정밀한 데이터 수집으로 정확한 환자의 진단이 이루어 질 수 있도록 기존 모듈들의 문제점을 보완하였다.

• 자원환경지질
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• 제50권3호
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• pp.251-256
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• 2017

본 연구는 폐광산에서 배출되는 산성광산배수가 하천수 및 지하수에 유출되면서 발생되는 환경 오염들을 막기 위해 생물학적 자연정화 처리 방법인 연속적 알칼리도 생성 시스템의 효율을 증대 시키는 방안에 관한 연구이다. 연속적 알칼리도 생성 시스템를 이용한 산성광산배수의 처리는 대부분 황산염 환원 박테리아를 이용한 생물학적 처리 기술이며, 실제 현장 적용실험에서 그 효과가 증명되었고, 광산배수 정화 사업에 적용하도록 개발된 사례가 많다. 그러나 계절적인 온도 저하로 기온이 매우 낮은 겨울이나 초봄 동안에는 황산염 환원 박테리아가 생존은 가능하더라도 황산염을 환원시키는 활동이 거의 멈추게 되어 지속적인 산성광산배수 처리 효율에 문제점을 야기한다. 본 연구에서는 연속적 알칼리도 생성 시스템에 발광 다이오드를 접목하여 유기물 층의 황산염 환원 박테리아 활성을 증진시키고, 온도가 낮은 겨울철에도 발광 다이오드의 발열 효과를 이용하여 활성 온도를 유지 할 수 있는 방안을 제안한다. 더불어, 산성광산배수 처리 시설은 전력을 쉽게 공급할 수 없는 곳에 위치한 지리적인 특성을 고려하여, 발광 다이오드에 전원을 공급할 수 있는 전원 공급 장치로 태양 전지 모듈 사용을 제안한다. 본 방법을 통하여 추가적 연구들이 진행된다면, 태양광 에너지와 발광 다이오드를 융합한 친환경적인 방법을 이용하여 겨울철에도 산성광산배수 처리 기술의 효율을 극대화 할 수 있을 것이다.

• 멤브레인
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• 제9권4호
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• pp.209-214
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• 1999

본 연구의 목적은 냉연공장 폐수재이용을 위해 3단 역삼투시스템 사용시 각단에서의 투과특성을 조사하는 것이다 판틀형 모듈 7개를 사용하여 회수율이 75% 가 되도록 3단 (배열 : 4+2+1) 으로 구성하여 장기간에 걸친 pilot test를 통해 막오염 진행에 따른 각 단에서의 유량 및 수질변화를 조사하였다 실험결과 각 단 모듈 1개당 평균 투과수량은 운전초기에는 1단, 2단, 3단의 순서로 많았으나 운전시간이 경과하며 막오염이 진행됨에 따라 1단은 감소하는 반면 2단은 거의 변화가 없고 3단의 투과수량은 증가하였다 즉 막오염은 주로 1단에서 발생하며 점차 2단. 3단으로 진행되는 것을 확인할수 있었다. 한편 투과수 수질은 예상한 것과 같이 1단이 가장 우수하였고 다음으로는 2단, 3단의 순서였으며 막오염에 영향을 받지않았다.