• 경영과정보연구
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• 제3권
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• pp.287-316
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• 1999

Cyberspace permits us to more beyond traditional face-to-face, mail and telephone surveys, yet still to examine basic issues regarding the quality of data collection: sampling, questionnaire design, survey distribution, means of response, and database creation. This article address each of these issues by contrasting and comparing traditional survey methods(Paper-and-Pencil) with Internet or Personal Computer networks-mediated (Screen-and-Keyboard) survey methods also introduces researchers to this revolutionary and innovative tool and outlines a variety of practical methods for using the Internet or Personal Computer Networks. The revolution in telecommunications technology has fostered the rapid growth of the Internet all over the world. The Internet is a massive global network and comprising many national and international networks of interconnected computers. The Internet or Personal Computer Networks could be the comprehensive interactive tool that will facilitate the development of the skills. The Internet or Personal Computer Networks provides a virtual frontier to expand our access to information and to increase our knowledge and understanding of public opinion, political behavior, social trends and lifestyles through survey research. Comparable to other technological advancements, the Internet or Personal Computer Networks presents opportunities that will impact significantly on the process and quality of survey research now and in the twenty-first century. There are trade-offs between traditional and the Internet or Personal Computer Networks survey. The Internet or Personal Computer Networks is an important channel for obtaining information for target participants. The cost savings in time, efforts, and material were substantial. The use of the Internet or Personal Computer Networks survey tool will increase the quality of research environment. There are several limitations to the Internet or Personal Computer Network survey approach. It requires the researcher to be familiar with Internet navigation and E-mail, it is essential for this process. The use of Listserv and Newsgroup result in a biased sample of the population of corporate trainers. However, it is this group that participates in technology and is in the fore front of shaping the new organizations of interest, and therefore it consists of appropriate participants. If this survey method becomes popular and is too frequently used, potential respondents may become as annoyed with E-mail as the sometimes are with mail survey and junk mail. Being a member of the Listserv of Newsgroup may moderate that reaction. There is a need to determine efficient, effective ways for the researcher to strip identifiers from E-mail, so that respondents remain anonymous, while simultaneously blocking a respondent from responding to a particular survey instrument more than once. The optimum process would be on that is initiated by the researcher : simple, fast and inexpensive to administer and has credibility with respondents. This would protect the legitimacy of the sample and anonymity. Creating attractive Internet or Personal Computer Networks survey formats that build on the strengths of standardized structures but also capitalize on the dynamic and interactive capability of the medium. Without such innovations in survey design, it is difficult to imagine why potential survey respondents would use their time to answer questions. More must be done to create diverse and exciting ways of building an credibility between respondents and researchers on the Internet or Personal Computer Networks. We believe that the future of much exciting research is based in the Electronic survey research. The ability to communicate across distance, time, and national boundaries offers great possibilities for studying the ways in which technology and technological discourse are shaped. used, and disseminated ; the many recent doctoral dissertations that treat some aspect of electronic survey research testify to the increase focus on the Internet or Personal Computer Networks. Thus, scholars should begin a serious conversation about the methodological issues of conducting research In cyberspace. Of all the disciplines, Internet or Personal Computer Networks, emphasis on the relationship between technology and human communication, should take the lead in considering research in the cyberspace.

• 청정기술
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• 제17권2호
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• pp.124-133
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• 2011

2006년 시행되어 온 RoHS 규제에 유해물질을 추가하여 더 강화된 RoHS II의 공표에 대비하여 본 연구에서는 RoHS II의 최우선 규제 물질이면서 2010년 발표된 REACH SVHC 후보목록에도 포함된 물질인 Hexabromocyclododecane (HBCDD) 및 3종 프탈레이트, Dibutyl phthalate (DBP), Butyl benzyl phthalate (BBP), Diethylhexyl phthalate (DEHP)의 국내 전기 전자제품내의 함유 여부를 사전 검토해보려는 목적으로 사례 연구를 진행하였다. 이에 고분자 소재로 구성된 세탁기, 냉장고, 혹은 전자렌지의 부품 20개를 12개 전기전자 부품 생산회사로부터 수거하여 4종 규제 물질을 기체크로마토그래피 질량분석법으로 분석하여 그 함유량을 측정한 결과 Nitrile Butadine Rubber (NBR), Polypropylene (PP), Polybutylene Terephthalate (PBT), Ethylene Propylene Rubber (EPDM), Polyvinyl Chloride (PVC) 등의 소재로 된 부품 중 HBCDD는 NBR 소재로 된 3종 부품에서 42~381 mg/kg 범위로 검출되어 규제값 0.1 wt% (1,000 mg/kg)보다는 적지만 주의를 요한다. DBP 및 BBP는 20개 부품모두에서 검출되지 않고 있어 이 두 물질은 전지전자 제품용 플라스틱 소재에서 넓게 사용되지 않고 있을 가능성을 시사하고 있다. 그러나 DEHP는 40~59,400 mg/kg 범위로 NBR, PP, PBT, EPDM 및 PVC로 이루어진 부품에서 모두 검출되어 광범위하게 사용되고 있음을 알 수 있었고 특히 NBR 및 PVC로 이루어진 8개 부품에서 예상 규제치인 0.1 wt% (1,000 mg/kg)을 훨씬 능가한 0.45~5.94 w%로 검출되고 있어 이에 대한 대비가 필요함을 알 수 있었다. 추가로 REACH SVHC (고위험성 물질)에 속하는 Diarsenic pentaoxide, Diarsenic trioxide, Lead hydrogen arsenate, Triethyl arsenate의 4종 물질의 함유 여부를 ICP에 의한 비소(Arsenic) 분석으로 스크리닝해 본 결과 NBR, PBT 소재의 4개 부품에서 15~700 mg/kg으로 검출되었고 이 중 PBT소재의 부품인 Thermistor에서는 규제되는 비소화합물이 규제값(0.1 wt%, 1,000 mg/kg)을 초과할 가능성이 매우 높다.

• 한국재료학회지
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• 제22권6호
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• pp.321-327
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• 2012

The production of functional activated carbon materials starting from inexpensive natural precursors using environmentally friendly and economically effective processes has attracted much attention in the areas of material science and technology. In particular, the use of plant biomass to produce functional carbonaceous materials has attracted a great deal of attention in various aspects. In this study the preparation of activated carbon has been attempted from rice husks via a chemical activation-assisted microwave system. The rice husks were milled via attrition milling with aluminum balls, and then carbonized under purified $N_2$. The operational parameters including the activation agents, chemical impregnation weight ratio of the calcined rice husk to KOH (1:1, 1:2 and 1:4), microwave power heating within irradiation time (3-5 min), and the second activation process on the adsorption capability were investigated. Experimental results were investigated using XRD, FT-IR, and SEM. It was found that the BET surface area of activated carbons irrespective of the activation agent resulted in surface area. The activated carbons prepared by microwave heating with an activation process have higher surface area and larger average pore size than those prepared by activation without microwave heating when the ratio with KOH solution was the same. The activation time using microwave heating and the chemical impregnation ratio with KOH solution were varied to determine the optimal method for obtaining high surface area activated carbon (1505 $m^2$/g).

• 한국도서관정보학회지
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• 제50권4호
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• pp.359-379
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• 2019

이 연구의 목적은 국내 대학도서관이 이용자를 위한 수업 및 학습활동 지원을 강화할 수 있는 방안을 제시하는 것이다. 이를 위하여, 전국 대학도서관의 발전계획서를 수집하고 발전계획서에 나타난 수업 및 학습 활동 지원 계획을 분석하였다. 연구의 결과, 가장 많은 도서관들이 '학습자료 확충'을 중시하여 발전계획서에서 추진계획을 밝힌 것으로 나타났다. 다음으로 '독서교육 및 독서프로그램 확대', '전자자료 확충', '특성화자료 확충' 순으로 실행계획을 제시하였다. 이 연구는 대학도서관의 수업 및 학습활동 지원 강화 방안으로 '수용자 중심의 장서개발 및 학습자료 확충', '빅데이터를 활용한 도서관 서비스 활성화', '장애인 및 외국인 학생을 위한 포용서비스 확대'를 제시하였다.

• 센서학회지
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• 제23권4호
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• pp.266-271
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• 2014

Chemical sensors are used in various industrial facilities such high-risk and prevent the leakage of substances, important in life and environmental protection and the safe use of industry, used for management. In particular, high-temperature environments such as power generation equipment of the rotating part due to leakage generated by the various oil, power plants Shut Down, fire, work environment (exposure to various chemical solution and gas leak) and various water, air and soil pollution causes. Thus, over the long term through various channels such as crops and groundwater contamination caused by the slow, serious adverse effect on the ecosystem. In this paper, synthetic lube oil and high pressure hydraulic fluid leakage and immediately detect a new Printed Electronic implementation of technology-based film-type sensors, and its performance test. Thus, industrial accidents and environmental pollution and for early detection of problems, large accidents can be prevented. Experimental results of the synthetic lube oil and high pressure hydraulic fluid solution after the contact time depending on the experiment and the oil solution of the sensor material of the conductive porous PE resistance value by a chemical reaction could be confirmed that rapid increase. Also implemented in the film-type oil sensor electrical resistance change over time of the reaction rate and the synthetic lube oil is about 2 minutes or less, the high pressure hydraulic fluid is less than about 1 minute was. Therefore, more high-pressure hydraulic fluid such as a low volatility synthetic lube oils are the resistance change and the reaction rate was confirmed to be the slowest.

• 한국분말재료학회지
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• 제13권5호
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• pp.321-326
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• 2006

Electronic packaging involves interconnecting, powering, protecting, and cooling of semiconductor circuits fur the use in a variety of microelectronic applications. For microelectronic circuits, the main type of failure is thermal fatigue, owing to the different thermal expansion coefficients of semiconductor chips and packaging materials. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers. The advantages of carbon nanofibers, especially the good thermal conductivity, are utlized to obtain a composite material having a thermal conductivity higher than 400 W/mK. The main challenge is to obtain a homogeneous dispersion of carbon nanofibers in copper. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed. In order to improve the bonding strength between copper and nanofibers, different alloying elements were added. The microstructure and the properties will be presented and the influence of interface modification will be discussed.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.214-219
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• 2009

In high-efficiency crystalline silicon solar cells, If high-efficiency solar cells are to be commercialized. It is need to develop superior contact formation method and material that can be inexpensive and simple without degradation of the solar cells ability. For reason of plated metallic contact is not only high metallic purity but also inexpensive manufacture. It is available to apply mass production. Especially, Nickel, Copper and Silver are applied widely in various electronic manufactures as easily formation is available by plating. The metallic contact system of silicon solar cell must have several properties, such as low contact resistance, easy application and good adhesion. Ni is shown to be a suitable barrier to Cu diffusion as well as desirable contact metal to silicon. Nickel monosilicide(NiSi) has been suggested as a suitable silicide due to its lower resistivity, lower sintering temperature and lower layer stress than $TiSi_2$. Copper and Silver can be plated by electro & light-induced plating method. Light-induced plating makes use the photovoltaic effect of solar cell to deposite the metal on the front contact. The cell is immersed into the electrolytic plating bath and irradiated at the front side by light source, which leads to a current density in the front side grid. Electroless plated Ni/ Electro&light-induced plated Cu/ Light-induced plated Ag contact solar cells result in an energy conversion efficiency of 14.68 % on $0.2{\sim}0.6{\Omega}{\cdot}cm,\;20{\times}20mm^2$, CZ(Czochralski) wafer.

• 한국물환경학회지
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• 제24권6호
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• pp.701-708
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• 2008

As a countermeasure for reduction of corrosion in the delivery and distribution pipes used for tap water, materials for the pipelines in-houses and the effect of water quality on corrosivity of water pipelines were investigated in the distribution system of Han river. As the corrosion index at 6 water purification facilities of Han river, average Langelier Saturation Index (LI) of raw and finished water were -1.0 and -1.4 respectively and average Larson Index (LR) were 9.5 and 9.9, respectively. And also corrosion potential showed corrosivity in finished water (-431~-462 mV) as well as raw water (-426~-447 mV). This results indicate that tap water quality of han river have corrosivity. To understand the corrosivity effect in pipe material used for premise distribution system, water quality of stagnant tap water and tap water were analyzed and the differences between them were calculated. The difference concentration of iron, copper and zinc were $12.9{\mu}g/L$, $31.0{\mu}g/L$ and $45.0{\mu}g/L$ respectively in galvanized steel pipe for use more than 15 years and showed highest concentration. As a result, the control to corrosivity in the water pipelines, corrosivity control treatment in the water purification system can be applied. In advance it is necessary to monitor corrosivity of water quality using corrosive index because corrosivity may differ from the seasonal and regional characteristics and water chemicals dosage. For the future the guideline for corrosion index have to be established.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
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• pp.43-55
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• 2000

In traditional electronic packages the die and the substrate are interconnected with fine wire. Wire bonding technology is limited to bond pads around the peripheral of the die. As the demand for I/O increases, there will be limitations with wire bonding technology. Flip chip technology eliminates the need for wire bonding by redistributing the bond pads over the entire surface of the die. Instead of wires, the die is attached to the substrate utilizing a direct solder connection. Although several steps and processes are eliminated when utilizing flip chip technology, there are several new problems that must be overcome. The main issue is the mismatch in the coefficient of thermal expansion (CTE) of the silicon die and the substrate. This mismatch will cause premature solder Joint failure. This issue can be compensated for by the use of an underfill material between the die and the substrate. Underfill helps to extend the working life of the device by providing environmental protection and structural integrity. Flux residues may interfere with the flow of underfill encapsulants causing gross solder voids and premature failure of the solder connection. Furthermore, flux residues may chemically react with the underfill polymer causing a change in its mechanical and thermal properties. As flip chip packages decrease in size, cleaning becomes more challenging. While package size continues to decrease, the total number of 1/0 continue to increase. As the I/O increases, the array density of the package increases and as the array density increases, the pitch decreases. If the pitch is decreasing, the standoff is also decreasing. This paper will present the keys to successful flip chip cleaning processes. Process parameters such as time, temperature, solvency, and impingement energy required for successful cleaning will be addressed. Flip chip packages will be cleaned and subjected to JEDEC level 3 testing, followed by accelerated stress testing. The devices will then be analyzed using acoustic microscopy and the results and conclusions reported.

• Advances in materials Research
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• 제6권2호
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• pp.169-184
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• 2017

Electro-Discharge machining (EDM) is a thermal process comprising a complex metal removal mechanism. This method works by forming of a plasma channel between the tool and the workpiece electrodes leading to the melting and evaporation of the material to be removed. EDM is considered especially suitable for machining complex contours with high accuracy, as well as for materials that are not amenable to conventional removal methods. However, several phenomena can arise and adversely affect the surface integrity of EDMed workpieces. These have to be taken into account and studied in order to optimize the process. Recently, artificial neural networks (ANN) have emerged as a novel modeling technique that can provide reliable results and readily, be integrated into several technological areas. In this paper, we use an ANN, namely, the multi-layer perceptron and the back propagation network (BPNN) to predict the mean surface roughness of electro-discharge machined surfaces. The comparison of the derived results with experimental findings demonstrates the promising potential of using back propagation neural networks (BPNNs) for getting a reliable and robust approximation of the Surface Roughness of Electro-discharge Machined Components.