• Journal of Welding and Joining
• /
• v.22 no.2
• /
• pp.38-45
• /
• 2004

Ultrasonic signals transmitted through adhesively bonded plates were used to evaluate parameters related to attenuation and frequency in the adhesively bonded joint. The kinds of bonding materials with a different bonding thickness of constant pressure were used. And ultrasonic diagnosis was evaluated by p-wave sensor of 10MHz. FFT has been performed to determine bond-layer parameters such as effective thickness and frequency for adhesively bonded joint of A16061 plates in comparison with measured to theoretical ratios. When variable thickness exists, the ultrasonic spectrum was changed the frequency wave. The more materials thickness and the higher the frequency, the larger shift was observed. Measured ratios for cases of bond thickness and variety bonding materials are then used to determine bond parameters. The results show that the technique can be applied to the characterization of adhesively bonded joint.

• Journal of Welding and Joining
• /
• v.21 no.5
• /
• pp.555-560
• /
• 2003

In automobile industry, it is necessary to reduce the weight from the view point of energy and environmental problems in these days. One of the ways for weight reduction is using adhesive aluminum structures. In this study, ultrasonic signals reflected from the adhesively bonded joint layer are used to evaluate the adhesively bonded joints. FFT is performed to determine bond-layer parameters such as effective thickness and frequency for adhesively bonded joint Al 6061 plates in comparison with the measured and theoretical ratios. And the parameters of ultrasonic wave and the J-integral are investigated to evaluate the adhesively bonded joint strength by DCB specimens.

• Transactions on Electrical and Electronic Materials
• /
• v.15 no.3
• /
• pp.159-163
• /
• 2014

More accurate CD (Critical Dimension) control is required for the nanometer-scaled devices. However, since the reflectivity between substrate and PR (Photoresist) becomes higher, the CD (Critical Dimension) swing curve was intensified. The higher reflectivity also causes PR notching due to the pattern of sub-layer. For this device requirement, it was optimized for the thickness, refractive index(n) and absorption coefficient(k) in the bottom anti-reflective coating(BARC; SiON) and photoresist with the minimum reflectivity. The computational simulated conditions, which were determined with the thickness of 33 nm, n of 1.89 and k of 0.369 as the optimum condition, were successfully applied to the experiments with no standing wave for the 0.13um-device. At this condition, the lowest reflectivity was 0.44%. This optimum condition for BARC SiON film was applied to the process for 0.13um-device. The optimum SiON film as BARC to PR and sub-layer could be formed with the accurate CD control and no standing waver for the nanometer-scaled semiconductor manufacturing process.

• Journal of the Korean Society of Food Culture
• /
• v.20 no.2
• /
• pp.204-213
• /
• 2005

This study was focused on the analysis of questionnaire that surveyed the uses, preference and recognition on apple. The subjects of this study consisted of 452 female(married 238, unmarried 214) in Daegu area. Among those respondents, 49.1% answered that they ate apple after dinner. Respondents preferred as purchase place fruits store(34.5%), traditional market(22.6%), and big discount store(21.7%), in order. Taste(46.0%) was the most important as purchase criterion. 49.1% of respondents preferred small amount below 2-3kg every one purchase. In preference survey on apples, 80.5% of total subjects responded 'like' or 'very like', and 73.6% of those subjects who favorably responded liked the 'taste' of apples. The preference survey study on apple foods revealed that respondents preferred the most apple juice(M=3.47), fellowed by apple jam(M=3.35) and apple vinegar(M=3.21). On the other hand, apple bab(M=2.29) and apple jook(M=2.23) had the most low preference score. The recognition survey study on apple revealed that respondents knew relatively well the followings: apple is natural food(M=4.25), apple is good for body and apple is good for beauty(M=4.20). Respondents required apple to be fresher(41.0%) and taster(37.4%). 89.4% of respondents expected that consumption of apples would be increased or maintain at the present level.

• Journal of the Korean Society for Heat Treatment
• /
• v.13 no.4
• /
• pp.259-264
• /
• 2000

In this study, we quantitatively measure the ion ranges of arsenic with energies ranging from 10 KeV to 100 KeV, implanted at $3^{\circ}$, $9^{\circ}$ $15^{\circ}$ the (100) plane, and the damage created during ion implantation. To obtain detailed information of ion range and damage distributions in low energy region where elastic collisions dominate the slowing down process, molecular dynamics computer simulation was performed and compared to the existing results. The effects of implant energy and degree on damage generation are present. The number of vacancy were calculated from the deposited energy using Kinchin-Pease equation. In the energy range 10 keV-100 keV, simulations show that the number of Frenckel pairs produced by As-ion bimbardment is 9 and incident angle dependence of the vacancy was the same but defects were distributed at different depth.

• Journal of the East Asian Society of Dietary Life
• /
• v.16 no.1
• /
• pp.107-112
• /
• 2006

This study analyzed the changes of chlorophyll and ascorbic acid contents according to the extraction temperatures and the number of soakings using five kinds of Korean and Japanese green tea(3 kinds of green tea and 2 kinds of tea bag) which were obtained from local markets in Korea and Japan. The findings are as follows: 1. The chlorophyll contents of Japanese green tea were $2\sim3$ times higher than those of Korean green tea. 2. The chlorophyll contents of Korean green tea in high and middle grades were increased with increasing temperature $(80>70>60^{\circ}C)$ but the contents in low grade were increased with decreasing temperature. The contents of chlorophyll in Japanese green tea were almost similar in low, middle and high grades. 3. Ascorbic acid content was higher in low grade Korean green tea but it was higher in high and middle grades of Japanese green tea. Chlorophyll contents of Japanese green tea were higher than those of Korean green tea but ascorbic acid contents of Korean green tea were higher than those of Japanese green tea.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.3
• /
• pp.75-80
• /
• 2006

Since air pollution has become a globally critical issue and exhaust emissions from automobiles cause a major source of air pollution, many countries including advanced countries have stipulated stringent emission regulations. Particularly in diesel vehicles, NOx and particulate matters exhaust in significant amounts even though diesel vehicles provide merits in aspects of higher thermal efficiency and lower $CO_2$. To reduce Particulate matters and NOx, after-treatment technology such as filter trap, oxidation catalysts and EGR has been applied. This test was conducted on the effect of continuous regeneration diesel particulate filter and cooled-EGR, and 15ppm low sulfur diesel was used as a test fuel. Exhaust emissions, PM, NOx, CO, HC and Soots were measured and compared under D-13 and D-3 modes.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.10
• /
• pp.543-553
• /
• 2020

This paper examines the effect of COVID-19 pandemic on the Philippine stock exchange, peso-dollar rate and retail price of diesel using robust least squares regression and vector autoregression (VAR). The robust least squares regression using MM-estimation method concluded that COVID-19 daily infection has negative and statistically significant effect on the Philippine stock exchange index, peso-dollar exchange rate and retail pump price of diesel. This is consistent with the results of correlation diagnostics. As for the VAR model, the lag values of the independent variable disclose significance in explaining the Philippine stock exchange index, peso-dollar exchange rate and retail pump price of diesel. Moreover, in the short run, the impulse response function confirmed relative effect of COVID-19 daily infections and the variance decomposition divulge that COVID-19 daily infections have accounted for only minor portion in explaining fluctuations of the Philippine stock exchange index, peso-dollar exchange and retail pump price of diesel. In the long term, the influence levels off. The Granger causality test suggests that COVID-19 daily infections cause changes in the Philippine stock exchange index and peso-dollar exchange rate in the short run. However, COVID-19 infection has no causal link with retail pump price of diesel.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.10
• /
• pp.523-530
• /
• 2020

The efficient market hypothesis explains the random walk hypothesis suggesting that stock prices are independent of each other, hence, it is impossible to earn abnormal profits. The positive effect of a well-functioning and highly efficient stock market on the performance of an economy motivated the Philippine Stock Exchange to pursue massive modernization initiatives. This research provides evidence of the existence of random walk in the Philippine stock market employing the Augmented Dickey-Fuller (1981) and Phillips-Perron (1988) unit root tests, the Lo-MacKinlay's (1988) conventional variance ratio test, and Chow-Denning's (1993) simple multiple variance ratio test. Results of the ADF and PP unit root tests confirm the necessary condition for a random walk. The Chow-Denning (1993) maximum /z/ statistic and the Wald test statistic as in Richardson and Smith (1991) for the joint hypotheses and the Lo and MacKinlay (1988) individual statistics variance ratio test generally accepted the null hypothesis of a random walk. That is, the unit root and variance ratio tests consistently indicate that the null hypothesis of random walk cannot be rejected. The existence of a random walk in weak-form efficiency can be attributed to market liquidity as a result of continuous development and modernization of the Philippine equity market.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.1058-1059
• /
• 2015

최근 건축 구조물 설계에 있어서 외부 또는 내부로부터 발생될 수 있는 미지의 진동에 대하여 대책을 수립하여 구조물을 설계하고 있다. 뿐만 아니라 기타 제조업 분야에 있어서 정밀할 가공이 필요한 특수한 기계 가공기에 있어서 내부 또는 외부에서 발생될 수 있는 진동을 감안하여 시스템을 구성하고 있다. 이러한 구조물 및 기계시스템에 대하여 진동을 억제할 수 있는 진동 억제 알고리즘에 관해서는 많이 연구되고 있다. 본 논문에서는 구조물 및 기계시스템에서 발생될 수 있는 미지의 외란을 제거하기 위하여 내부모델제어(IMC)를 기반으로 수정된 적응 알고리즘을 매트랩 시뮬링크(matlab simulink)를 통하여 제어성능을 제시하고자 한다.