• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.505-510
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• 2012

Cobalt oxide nanostructure materials have been prepared by adding several concentrations of spectator Ni ions in solution, and analyzed by electron microscopy, X-day diffraction, calorimetry/thermogravimetric analysis, UV-vis absorption, Raman, and X-ray photoelectron spectroscopy. The electron microscopy results show that the morphology of the nanostructures is dramatically altered by changing the concentration of spectator ions. The bulk XRD patterns of $350^{\circ}C$-annealed samples indicate that the structure of the cobalt oxide is all of cubic Fd-3m $Co_3O_4$, and show that the major XRD peaks shift slightly with the concentration of Ni ions. In Raman spectroscopy, we can confirm the XRD data through a more obvious change in peak position, broadness, and intensity. For the un-sputtered samples in the XPS measurement process, the XPS peaks of Co 2p and O 1s for the samples prepared without Ni ions exhibit higher binding energies than those for the sample prepared with Ni ions. Upon $Ar^+$ ion sputtering, we found $Co_3O_4$ reduces to CoO, on the basis of XPS data. Our study could be further applied to controlling morphology and surface oxidation state.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.398-402
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• 2012

ZnSe/$SiO_2$ coaxial nanowires were synthesized by a two-step process: thermal evaporation of ZnSe powders and sputter-deposition of $SiO_2$. Two different types of nanowires are observed: thin rod-like ones with a few to a few tens of nanometers in diameter and up to a few hundred of micrometers in length and wide belt-like ones with a few micrometers in width. Room-temperature photoluminescence (PL) measurement showed that ZnSe/$SiO_2$ coaxial nanowires had an orange emission band centered at approximately 610 nm. The intensity of the orange emission from the $SiO_2$-sheathed ZnSe nanowires was enhanced significantly by annealing in a reducing atmosphere whereas it was degraded by annealing in an oxidizing atmosphere. The origins of the PL changes by annealing are discussed based on the energy-dispersive X-ray spectroscopy analysis results.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.139-146
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• 2011

In present study, it aims to compare the noise and vibration characteristics between magnesium alloy and steel hood panel. The AZ31 magnesium hood panel was fabricated through warm forming process, and the noise and vibration characteristics between both hood panels was compared through the measurement of engine radiation noise and transmission loss, as well as FRF on modal analysis. The sound insulation performance of magnesium alloy was wholly superior to that of steel hood panel, even though the transmission loss of magnesium alloy is lower than that of steel due to mass effect primarily. The FRF characteristics on modal analysis indicates that the resonance frequency of magnesium hood panel is remarkably increased to higher value than that of steel hood panel. The radiation and interior noise of magnesium panel even without acoustic hood insulation were remarkably lower than those of steel hood panel with acoustic insulation, in particular, at a range below 4,000 rpm.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.123-129
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• 2013

Among various manual materials handling tasks, pushing/pulling was known to be one of the risk factors for the low back and shoulder musculoskeletal disorders (MSDs). This study was conducted to find out an optimal solution set of the handle height and distance for 4-wheel cart with two vertical handles. Ten male college students participated in the pushing force measurement experiment. The face-centered cube design, one of the central composite designs, was applied for the experiment, and the isometric voluntary pushing force was measured in 9 treatment conditions. The second order response surface model was predicted by using the pushing strength as a response variable, and the handle height and distance as independent factors. According to the 2nd order response model, the handle height and distance showed nonlinear relationship with the isometric pushing strength. To maximize the 2nd order response model (pushing force), the handle height and distance were optimized. The optimal handle height was 'xyphoid process height - stature', and the optimal handle distance was '$1.25{\times}shoulder$ width'. When calculated using the anthropometric data of the subjects of this study, the optimal handle height was $115.4{\pm}3.4$ cm, slightly higher than the elbow height, and the handle distance was $52.9{\pm}2.3$ cm.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.1-8
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• 1991

Recently, researches for buried lifelines such as pipelines have been carried out to provide for safe design. On of the major causes to the damage of buried pipelines has been soil liquefaction. Analytical models have been presented to compare with the results from recent model experiment under a soil liquefaction environment induced by seismic shaking table. The analytical results were more than two times those those of experimental measurement. Thus the objective of this study is to introduce a rigorous nonlinear analysis of equation of motion with more realistic parameters which are dynamic soil and water pressure, dynamic subgrade reaction coefficient, and damping coefficient for soil liquefaction environment.

• World Technopolis Review
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• v.1 no.3
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• pp.177-185
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• 2012

In recent years, some experts have shown that urban competitiveness is more important than national competitiveness. They have also argued that innovation will make cities more competitive. The purpose of this paper is to create Korean urban competitiveness index, and to also highlight strategic aspects for enhancement of urban competitiveness of metropolitan cities based on innovation in Korea. First, we will present various factors and indicators of urban competitiveness based on three components for innovation: formation of cluster, human capital, creative economy. Available literature and statistical analyses will be used. Second, scores of urban competitiveness will be developed based on Analytic Hierarchy Process (AHP). Evaluation of scores with weights will be used for this purpose. The resulting weights are 0.3672 for the formation of cluster, 0.3318 for human capital, and 0.3010 for creative economy, respectively. Finally, we present urban competitiveness using the standardized T-score. The most competitive city based on innovation is Daejeon(1st), followed by Gwangju(2nd) and Daegu(3rd). Three least competitive cities are Incheon (6th), Busan(5th) and Ulsan(4th).

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.163.1-163.1
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• 2010

MTO 공정을 개발하기 위한 순환유동층 장치에서 고체순환량을 높이기 위해 고체 주입량 및 상승관 유속에 따른 수력학적 특성의 파악에 관한 연구를 수행하였다. 전체 높이 2.6m 직경 0.009m의 상승관을 가진 순환유동층 장치에 대해 고체순환량을 조절하기 위한 비기계적 밸브로 각각 Seal-pot과 L-valve가 장착된 두 장치에 대해 고체순환량 및 체류량을 측정하였다. 고체순환량 및 체류량은 두 장치에서 모두 고체의 주입량이 증가함에 따라 증가하는 모습을 나타내었으며, 상승관의 유속에 따라서는 특정한 유속의 범위 내에서 증가하다가 일정 유속 이후 감소하는 모습을 나타내었다. Seal-pot을 사용한 장치에서는 고체순환량이 최대 $87kg/m^2.s$ 가량의 값을 나타내었으나 L-valve를 사용한 장치에서는 최대 $180kg/m^2.s$를 보였다. 이러한 실험 결과를 바탕으로 하여 전산유체역학을 이용한 순환유동층의 유동해석에 관한 연구를 실시하여 실험조건의 변화에 따른 상승관 내부의 수력학적 특성을 비교하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.8 no.1
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• pp.85-89
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• 1968

The author has carried out the statistical standards on liner and angular measurements of sells turcica in 244 normal Korean of various age group by means of lateral cephalometric radiography. The results were as follows; 1. The linear measurements between Ant-Post distance and distance from the tip of tuberculum of sellae to posterior clinoid process were obtained 14.81mm, 9.85mm in the age of 5 years old male and 14.44mm, 9.52mm in female, respectively. There was no outstanding difference with age, but more predominant in female than male. 2. The linear measurements of inferior depth show somewhat increases but no changes in superior depth. 3. It has been showed that the greatest width revealed significant increment beyond 15 years old of both sexes in Korean. 4. None of the significant difference in angular measurement was found with age, but angulation for dorsum sellae decreased after 15 years of male. 5. Generally speaking, increment rates of female in each items were greater than male.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1234-1242
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• 2003

In this paper we present a simple and efficient robust optimal design formulation for MEMS structures and its application to a resonant-type micro probe. The basic idea is to use the gradient index (GI) to improve robustness of the objective and constraint functions. In the robust optimal design procedure, a deterministic optimization for performance of MEMS structures is followed by design sensitivity analysis with respect to uncertainties such as fabrication errors and change of operating conditions. During the process of deterministic optimization and sensitivity analysis, dominant performance and uncertain variables are identified to define GI. The GI is incorporated as a term of objective and constraint functions in the robust optimal design formulation to make both performance and robustness improved. While most previous approaches for robust optimal design require statistical information on design variations, the proposed GI based method needs no such information and therefore is cost-effective and easily applicable to early design stages. For the micro probe example, robust optimums are obtained to satisfy the targets for the measurement sensitivity and they are compared in terms of robustness and production yield with the deterministic optimums through the Monte Carlo simulation. This method, although shown for MEMS structures, may as well be easily applied to conventional mechanical structures where information on uncertainties is lacking but robustness is highly important.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.845-852
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• 2020

The study aims to investigate the implementation of the internal quality assurance system (IQAS) on HEIs performance, mediated by financial management accountability. The commitment from foundation leadership on financial management accountability and their implications for HEIs' performance is also carefully examined. This study employs samples of 108 respondents from the leadership of private HEIs under Region IV Service Institutions. The purposive sampling, as a part of non-probability sampling was chosen as the sampling technique. Statistical data analysis conducted by use the structural equation model to test the hypothesis. The results reveal that the implementation of IQAS does not influence the financial management accountability, but it has an essential role on HEIs' performance. Moreover, foundation leadership's commitment has a significant positive effect on financial management accountability and HEIs' performance. Financial management accountability also has a significant positive effect on HEIs' performance. Financial management becomes important because the entire activities of HEIs should end with financial reporting. Therefore, financial and non-financial aspects are two interrelated and complementary aspects in the accreditation process. The findings of this study suggest that that performance measurement is very crucial as a part of the efforts to meet the general accountability requirement for organizations, particularly in HEIs.