• Journal of Welding and Joining
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• 제26권3호
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• pp.30-36
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• 2008

A flip-chip bonding system using IR laser with a wavelength of 1064 nm was developed and associated process parameters were analyzed using Taguchi methods. An infrared laser beam is designed to transmit through a silicon chip and used for transferring laser energy directly to micro-bumps. This process has several advantages: minimized heat affect zone, fast bonding and good reliability in the microchip bonding interface. Approximately 50 % of the irradiated energy can be directly used for bonding the solder bumps with a few seconds of bonding time. A flip-chip with 120 solder bumps was used for this experiment and the composition of the solder bump was Sn3.0Ag0.5Cu. The main processing parameters for IR laser flip-chip bonding were laser power, scanning speed, a spot size and UBM thickness. Taguchi methods were applied for optimizing these four main processing parameters. The optimized bump shape and its shear force were modeled and the experimental results were compared with them. The analysis results indicate that the bump shape and its shear force are dominantly influenced by laser power and scanning speed over a laser spot size. In addition, various effects of processing parameters for IR laser flip-chip bonding are presented and discussed.

• 대한화학회지
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• 제55권3호
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• pp.495-501
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• 2011

플라보노이드계 화합물인 HMPC (3-hydroxy-7-methoxy-2-phenylchromen-4-one의 부식억제성질, HMPC와 TBAB(n-tetrabutylammonium bromide) 간 상승효과, 염산 조건하 부드러운 강철의 흡착성질을 무게 감량, 변전위 편극, 전기화학 임피던스 분광기를 사용하여 연구하였다. 다양한 온도에서 무게 감량 측정 실험한 결과 부식 억제 효율은 억제제 농도가 증가함에 따라 증가하였고, 계의 온도가 증가함에 따라 감소하였다. 전기화학 실험 결과 부식 억제는 여러 혼합된 형태의 억제 방법에 의해 가능하였다. 금속 표면에 흡착된 억제 화합물 분자는 보호막을 형성하였다.

• 농업과학연구
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• 제39권3호
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• pp.413-420
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• 2012

Spectroscopic measurement method based on visible and near-infrared wavelengths was prominent technology for rapid and non-destructive evaluation of internal quality of fruits. Reflectance measurement was performed to evaluate firmness, soluble solid content, and acid content of truss tomatoes by hyperspectral reflectance imaging system. The Vis/NIR reflectance spectra was acquired from truss tomatoes sorted by 6 ripening stages. The multivariable analysis based on partial least square (PLS) was used to develop regression models with several preporcessing methods, such as smoothing, normalization, multiplicative scatter correction (MSC), and standard normal variate (SNV). The best model was selected in terms of coefficient of determination of calibration ($R_c^2$) and full cross validation ($R_{cv}^2$), and root mean standard error of calibration (RMSEC) and full cross validation (RMSECV). The results of selected models were 0.8976 ($R_p^2$), 6.0207 kgf (RMSEP) with gaussian filter of smoothing, 0.8379 ($R_p^2$), $0.2674^{\circ}Bx$ (RMSEP) with the mean of normalization, and 0.7779 ($R_p^2$), 0.1033% (RMSEP) with median filter of smoothing for firmness, soluble solid content (SSC), and acid content, respectively. Results show that Vis / NIR hyperspectral reflectance imaging technique has good potential for the measurement of internal quality of truss tomato.

• 한국전자통신학회논문지
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• 제12권5호
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• pp.923-932
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• 2017

본 논문에서는 기존의 문제점인 얼굴 움직임이 있을 시 시선 식별이 어려운 점과 사용자에 따른 교정작업이 필요하다는 점을 해결하고자 새로운 시선 식별 시스템과 얼굴인식에 필요한 GRNN(: Generalized Regression Neural Network) 알고리즘을 제안한다. Kalman필터를 사용하여 현재 머리의 위치정보를 이용하여 미래위치를 추정하였고 얼굴의 진위 여부를 판단하기 위해서 얼굴의 특징요소를 구조적 정보와 비교적 처리시간이 빠른 수평, 수직 히스토그램 분석법을 이용하여 얼굴의 요소를 검출한다. 그리고 적외선 조명기를 구성하여 밝은 동공효과를 얻어 동공을 실시간으로 검출, 추적하였고 동공-글린트 벡터를 추출하여 의료정보 보호에 도움을 주고자 한다.

• 한국가구학회지
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• 제22권1호
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• pp.72-81
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• 2011

These days, beds have been developed not as furniture to sleep in but Healthcare Furniture. The function of heating, non-electronic-waves and far-infrared rays have been added. Also, eco-friendly materials such as stone, mud, rubber and wood are combined to them together with the radiation-heating method using heat conduction through electronic coil and hot water circulation. Modern people suffer from stress and fatigue. The hot issue is "health." Focused on the health, the development of design for beds considering the influence electronic waves, anions, deep sleep and the density of toxic materials have on human bodies has become urgent. In this study, the trend, specification and efficiency of the functional health-related electronic coil technology are analyzed. Through the analysis, the environmental standards are set. According to them, technology, eco-friendly materials and additional functions for the development of the design are considered. Also, the government is promoting the IEC international standardization for the Korean traditional floor heating style beds. In preparation for that, we adopted new HPT method technology. It enables non-electronic-waves, low electricity and stable temperature maintenance control for the warm top and the cool bottom. Also, the head boards and the frames of the beds can be separated. Through this separation, the beds can be easily moved or installed. Eco-friendly materials such as Hinoki cypress wood and red clay and the existing tables function are combined to the head boards so they can be used as drawers and display shelves. If they are used as separate items, they can be used as covers. This is how we suggest the design for the heating beds.

• 한국안전학회지
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• 제33권5호
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• pp.15-20
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• 2018

This paper describes the fusing time characteristics of Light PVC Sheathed Circular Cord(VCTF) and Tray Frame Retardant(TFR) cables according to increased temperature under over current condition. The experimental equation will be used to determine the validity and reliability of the test results. The over current flowed 3, 5 and 10 times higher than the amount of allowable current using DC power supply with DAQ(Data Acquisition) measurement system. An infrared radiation heater, which was controlled by a variable AC auto transformer, was used to increase the temperature from room temperature to 50, 100 and 150 degrees Celsius. First, two type of cables were analyzed those with different cross-sectional areas with in the same structure and those with different structures with in the same cross-sectional areas. Then, it was determined how fusing time had been influenced according to the cross-sectional areas and different structures, respectively. The cable resistance was increased by joule heating according to increasing temperature. Therefore, the allowable current of cable is decreased. Finally, the fusing time of the cable was decreased due to increased temperatures at current flow, which were 3 times the amount of allowable current. The instantaneous breakdown was observed when current flow was 5 and 10 times over the amount of allowable current. The fusing time is directly affected by the structure of cable insulation.

• 한국세라믹학회지
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• 제48권1호
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• pp.63-68
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• 2011

The investigation is directed to lead free (Pb-free) frits that can be used for organic light emitting diode, plasma display screen devices and other sealing materials. $P_2O_5$-SnO system glasses have been prepared for Pb-free low temperature glass frit. Structure and properties of the glasses with the composition SnO-$xB_2O_3-(60-x)P_2O_5$ (x=0, 5, 10, 15, 20, 25, 30, 35, 40 mol%) were characterized by infrared spectra (IR), X-ray diffraction(XRD), Density, Molar volume, Thermo mechanical analysis(TMA) and weight loss after immersion test. Glass transition temperature($T_g$), dilatometric softening temperature($T_d$) and chemical durability increased, and coefficient of thermal expansion($\alpha$) decrease with the substitution of $B_2O_3$ for $P_2O_5$ in the range of 0~25 mol%.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• 한국운동역학회지
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• 제25권3호
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• pp.353-361
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• 2015

Objective : The aim of this study was to develop the non-powered horse riding device and was to evaluate the elaborate its applicability throughout static structural and transient structural analysis of the outdoor core strength exercise equipment. Method : Fifteen college students (mass: $69.55{\pm}13.38kg$, height: $1.69{\pm}5.61m$, age: $21.42{\pm}1.83yrs$) rode the powered horse riding device and 14 college students (mass: $71.12{\pm}9.74kg$, height: $1.73{\pm}3.31m$, age: $22.50{\pm}1.47yrs$) rode the non-powered horse riding device for the comparison. All motion capture data was collected at 100 Hz using six infrared cameras and the muscular activities were collected using a Delsys Trigno wireless system. The peak forward/backward lean angle, range of motion anter/posterior and vertical COM(Center of mass) movement of trunk and pelvis segment, and muscle activities of six muscles were compared between the two devices by using independent t-test (p<.05). Results : Several kinematic variables (peak forward-backward lean angle and vertical COM movement of trunk and pelvis segment, range of motion of trunk) significantly different between non-powered and powered horse riding device. The muscle activities of Rectus abdominis and External oblique of abdomen on the non-powered horse riding device were significantly greater than those of the powered device. Conclusion : It was concluded that non-power horse riding device could give the effect of core strength exercise as well as the body motion which can simulate the powered horse riding device.

• 한국정보통신학회논문지
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• 제10권5호
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• pp.897-904
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• 2006

리오그랑디주에서 바이아주 남부까지 약 300 km에 이르는 길고 좁은 브라질 북동부 지역에서는 남동무역풍의 교란, 전선의 침투, 해륙풍 순환 그리고 지형과 수증기 플럭스에 기인하는 국지 대류와 같은 다양한 강수 시스템이 나타난다. 연간 총강수량은 내륙에서는 600 mm, 해안지역에서는 3000 mm의 분포를 보이고 있다. 지역 기후 평균에 5-12배의 강수량이 2004년 1월에 알라고아스주 여러 지역에서 기록되었다. 46,000명의 수재민이 발생했고, 10,000,000 US$의 재산 피해였다. 이 폭우는 $21^{\circ}W,\;12^{\circ}S$에서 형성된 UTCV가 1월 내내 브라질 북동부 지역에 머물면서 영향을 미쳤기 때문이라는 것을 GOES 적외선 영상 분석으로 알 수 있었다.