• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.1053-1060
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• 2003

The temperature variation of the concrete pavement in the early age significantly affects the initiation and propagation of its early age cracks. This implies that the measurement and analysis of early age temperature trend are necessary to examine the causes of early age cracks in the concrete pavement. In this study, it is investigated how the early age temperature trend in the concrete pavement affects the random crack initiation and behaviors of saw-cut joints using the actual construction site which is located at the KHC test road. During 72 hours after placing the concrete pavement, the ambient air temperature and temperatures at the top, middle, and bottom in the concrete pavement were measured and the random crack initiation in concrete slabs and early age behaviors in the joints were surveyed. The investigation results indicate that the first random crack was initiated at one of the slabs placed in the early morning which have higher temperature changes during early 72 hours. In addition, the joints that were saw-cut in the morning were cracked more rapidly than those saw-cut in the afternoon.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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• pp.151-155
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• 2003

The requirements for harsh environment electronic controllers in automotive applications have been steadily becoming more and more stringent. Electronic substrate technologists have been responding to this challenge effectively in an effort to meet the performance, reliability and cost requirements. An effect of the plasma cleaning at the alumina substrate and the IMC layer between $Sn-37wt\%Pb$ solder and Ag-Pd thick film conductor after reflow soldering has been studied. Organic residual carbon layer was removed by the substrate plasma cleaning. So the interfacial adhesive strength was enhanced. As a result of AFM measurement, Ag-Pd conductor pad roughness were increased from 304nm to 330nm. $Cu_6Sn_5$ formed during initial ref]ow process at the interface between TiWN/Cu UBM and solder grew by the succeeding reflow process so the grains had a large diameter and dense interval. A cellular-shaped $Ag_3Sn$ was observed at the interface between Ag-Pd conductor pad and solder. The diameters of the $Ag_3Sn$ grains ranged from about $0.1\~0.6{\mu}m$. And a needle-shaped $Ag_3Sn$ was also observed at the inside of the solder.

• Structural Engineering and Mechanics
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• 제47권6호
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• pp.757-771
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• 2013

We present a semi-rigid connection estimation method by using cross modal strain energy method. While rigid or pinned assumptions are adopted for steel frames in traditional modeling via finite element method, the actual behavior of the connections is usually neither. Semi-rigid joints enable connections to be modeled as partially restrained, which improves the quality of the model. To identify the connection stiffness and update the FE model, a newly-developed cross modal strain energy (CMSE) method is extended to incorporate the connection stiffness estimation. Meanwhile, the relations between the correction coefficients for the CMSE method are derived, which enables less modal information to be used in the estimation procedure. To illustrate the capability of the proposed parameter estimation algorithm, a four-story frame structure is demonstrated in the numerical studies. Several cases, including Semi-rigid joint(s) on single connection and on multi-connections, without and with measurement noise, are investigated. Numerical results indicate that an excellent updating is achievable and the connection stiffness can be estimated by CMSE method.

• Wind and Structures
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• 제31권4호
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• pp.363-371
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• 2020

Proper understanding of offshore wind speed variability is of essential importance in practice, which provides useful information to a wide range of coastal and marine activities. In this paper, long-term wind speed data recorded at various offshore stations are analyzed in the framework of fractal dimension analysis. Fractal analysis is a well-established data analysis tool, which is particularly suitable to determine the complexity in time series from a quantitative point of view. The fractal dimension is estimated using the conventional box-counting method. The results suggest that the wind speed data are generally fractals, which are likely to exhibit a persistent nature. The mean fractal dimension varies from 1.31 at an offshore weather station to 1.43 at an urban station, which is mainly associated with surface roughness condition. Monthly variability of fractal dimension at offshore stations is well-defined, which often possess larger values during hotter months and lower values during winter. This is partly attributed to the effect of thermal instability. In addition, with an increase in measurement interval, the mean and minimum fractal dimension decrease, whereas the maximum and coefficient of variation increase in parallel.

• 대한한방소아과학회지
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• 제20권3호
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• pp.23-32
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• 2006

Objectives : The object of this study was to evaluate the effect of oriental medical treatment to the growth of children using bone age as measurer. Methods : This clinical study has been carried out with 32 cases(male 15, female 17 of children) aging from 7 to 15 years old, who visited to the Department of Pediatrics growth clinic, ○○ medical center from January 2004 to August 2006 and were treated for more than 12 months. Their height, body weight, body mass index(BMI) and bone age were estimated at two points: Before and after oriental medical treatment was applied. Bone age is measured by X-ray image of growth plate in inferior radiocarpal joint. Results : Bone age correlated with choronological age, height, weight. Difference between bone and choronological age was correlated with percentile of height and weight. The mean growth of children showed 4.03 percentile upwardly(p=.046), and difference between bone and choronological age was reduced from $0.23{\pm}1.62$ to $-0.026{\pm}1.64(p=.040)$ after treatment. Conclusions : This study shows that oriental medical treatment helped growth of children using bone age as measurer.

• 턱관절균형의학회지
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• 제5권sup호
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• pp.25-30
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• 2015

본 증례에서는 MRI상 극심한 요추 척추관 협착증 소견을 받고 요통과 하지 방사통으로 일상생활이 어려워 수술적 치료를 예정 받은 환자에게서 음양균형장치를 포함한 PBT, 침치료 등 구조적 치료를 통해서도 유의한 치료변화가 나타남을 관찰하였고 자각적 통증 및 보행 시간의 호전이 있어 이를 보고하는 바이다.

• 턱관절균형의학회지
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• 제4권1호
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• pp.21-26
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• 2014

본 증례에서는 원인 불명의 만성 재발성 악관절 탈구 및 개구 장애에 대해 CBA, TBA를 비롯한 FCST의 구조적 치료를 통해서도 유의한 치료변화가 나타남을 관찰하였다.

• 턱관절균형의학회지
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• 제6권1호
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• pp.5-10
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• 2016

본 증례에서는 구안와사환자에게 음양균형장치를 포함한 표준형 구강내 균형장치, 침구치료, 골반교정 등 복합치료를 통해 유효한 임상경과를 보인 결론은 다음과 같다. 1. 안면신경은 주행이 길고 측두골내에서 좁은 골관을 지나기 때문에, 좌상(bruised) 등 여러 가지 이유에 의하여 골도속의 신경 부종과 혈액순환 장애로 지연성 마비를 일으킨다. 2. 음양균형장치와 표준형구강내 균형장치 등 턱관절의 균형조절을 통한 기능적뇌척주요법의 치료가 안면신경마비의 치료에 효과적인 방법인 것을 관찰하였다. 기존의 구안와사의 경우 대부분 뚜렷한 치료방법을 선택하기가 어려웠으나, 이 증례를 통해 볼 때 수술 등의 대증요법을 하지 않고 기능적뇌척주요법 치료의 접근을 시도해 볼 수 있는 가능성이 있다고 사료된다.

• Journal of Welding and Joining
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• 제19권3호
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• pp.311-316
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• 2001

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.

• The Journal of Korean Physical Therapy
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• 제23권6호
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• pp.37-42
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• 2011

Purpose: The aim of this study is to suggest the basic materials for proposing effective and efficient methods when stretching by measuring isokinetic muscular strength according to static, dynamic and PNF stretching. Methods: This study was conducted on 45 healthy persons (male and female) in their twenties who are attending universities. The subjects are randomly divided into three (3) groups, and static stretching is applied in group 1, dynamic stretching is applied in group 2 and PNF stretching is applied in group 3. After carrying out static, dynamic and PNF stretching, peak torque was measured using isokinetic muscular strength measurement. Results: According to the results, at $60^{\circ}$/sec and $180^{\circ}$/sec isokinetic peak torque of the knee joint according to types of stretching, the largest changes were shown in Group 2 extension and flexion, and the least changes were shown in Group 1. There were significant differences among the three groups (p<0.05), and the result of after-analysis by LSD showed that there were significant differences between Groups 1 and 2, and Groups 1 and 3 (p<0.05). Conclusion: The intention of this study was to determine the peak torque using Cybex after applying three stretching methods to hamstring muscles, and the case of dynamic and PNF stretching was found to be more significant in both the $60^{\circ}$/sec and $180^{\circ}$/sec angular speeds than that of static stretching. Using the results of such studies, if dynamic and PNF stretching are applied together with warming-up before performing sports, the risk of suffering wounds would reduce and the exactness of sports would increase.