• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.113-113
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• 2008

Cu CMP (Chemical Mechanical Planarization) has been used to remove copper film and obtain a planar surface which is essential for the semiconductor devices. Generally, it is known that chemical reaction is a dominant factor in Cu CMP comparing to Silicon dioxide CMP. Therefore, Cu CMP slurry has been regarded as an important factor in the entire process. This investigation focused on understanding the effect of corrosion inhibitor on copper surface and CMP results. Benzotriazole (BTA) was used as a corrosion inhibitor in this experiment. For the surface analysis, electrochemical characteristics of Cu was measured by a potentiostat and surface modification was investigated by X-ray photoelectron spectroscopy (XPS). As a result, corrosion potential (Ecorr) increased and nitrogen concentration ratio on the copper surface also increased with BTA concentration. These results indicate that BTA prevents Cu surface from corrosion and forms Cu-BTA layer on Cu surface. CMP results are also well matched with these results. Material removal rate (MRR) decreased with BTA concentration and static etch rate also showed same trend. Consequently, adjustment of BTA concentration can give us control of step height variation and furthermore, this can be applicable for Cu pattern CMP.

• Journal of Astronomy and Space Sciences
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• 제4권1호
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• pp.11-23
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• 1987

외신성의 폭발 원인을 반성으로부터 accretion disk에 흘러들어온 물질유입량의 갑작스런 증가로 가정하였다. 따라서 $\alpha$-disk모델에서 source term을 100배로 증가시켜 Newton-Raphson 방법으로 풀었다. 구해진 disk의 물리적 변수들을 disk의 반경에 대해 나타냈으며, 시간에 따른 disk의 광도와 질량 변화를 구하였다. $\alpha$ 의 값을 각각 0.1, 0.12, 0.15, 0.18로 바꿔가며 유입되는 물질의 양이 일정할 때와 disk의 밝기가 가장 밝을 때의 변수들을 비교하였다. 이들 결과를 $1M_\bigodot$의 항성의 표면과 대기와 비교하였다.

• 한국산림과학회지
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• 제34권1호
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• pp.47-56
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• 1977

I have investigated and compared the morphology of vascular bundle shown in the section of culm wall of bamboo trees growing on Mt. Jiri which were classified by Grosser and Liese with their methods of morphological classification. The results obtained were as follows: 1. It was shown that there are no b.g.i. types of bamboo classified by Grosser and Liese among the bamboo trees on Mt. Jiri (Phyllostachys and Sasa). 2. As for the thickness of the culm wall in the culm, it was shown that the culm wall of the Phyllostachys becomes thinner in proportion to its nearness to the upper part of the tree, but no distinctive difference appeared in the Sasa. 3. The c, d, and e types of Sasa were the same as those of the Phyllostachys, but there was a vascular bundle type of the a' type, which was quite different from that of the Phyllostachys. 4. It was shown that the a', d, and e types of Sasa were distributed in a zone less than 500m above sea level, but no a' type was distributed in the high mountain area except for the c, d and e types which ranged from 600m to 1000m above sea level. Such facts mean that the vascular bundle sheath has changed in quantity because of the height of mountain. 5. In general, as compared with the Phyllostachys, the Sasa (types a, c, d and e which included a new type a) have fewer vascular bundles. 6. Considering the above results, it is thought that not by the current Sasa classification method based on observation of the the study of Sasa form the outside, but by a new method of classification based on the aspect of the physiological construction as seen from the inside wall is advanced. I believe this new method of classification to be a first step towards an epoch-making methodological advance and encourage the further study of it.

• 한국추진공학회지
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• 제16권4호
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• pp.50-56
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• 2012

벤트 혼합기는 혼합기 후류에 존재하는 재순환 영역으로 공기를 유입시켜 연료-공기 혼합을 증대시키는 혼합기이다. Stereoscopic PIV기법을 통해 얻은 3차원 속도, 와류, 난류운동에너지를 토대로 계단형 혼합기를 기본 모델로 하여 벤트 혼합기의 성능을 분석하였다. 벤트 혼합기는 두터운 전단층으로 인해 높은 침투거리를 보였으며, 난류운동에너지는 주로 주유동과 제트유동의 경계면을 따라 분포하였다. 이 난류 영역은 혼합영역 내에서 활발히 물질전달을 일으키며, 혼합 증대를 가져온다.

• 대한조선학회논문집
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• 제43권1호
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• pp.134-146
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• 2006

This paper presents the primary conceptual design results of twenty-passenger class Wing-In-Ground(WIG) effect craft. As a first step, top level requirements were proposed and principal dimensions were determined. Maximum speed in ground effect condition is 150 km/h with two tons payload including passengers. Total weight is estimated as 8.5 tons with 2 tons of thrust. Hull and airfoil sections were designed and self propulsion tests were performed by radio controlled model. Two planing hull forms with the transom stern were proposed and towing tests were performed. The resistance and running attitude were measured and the feasibility is checked for the prototype hull form of the twenty-passenger class WIG craft. The free running tests show the stable smooth running attitude at designed speed. Also this radio controlled model can take off around 0.15 meter wave height. It can be said that the top level requirement for the twenty passenger class WIG ship is satisfied successfully. The design optimization to increase the transport efficiency and safety will be performed in the near future.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.26-33
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• 2020

This study measured the downward stepping movement relative to weight change (no load, and 10%, 20%, 30% of body weight respectively of adult male (n=10) from standardized stair (rise of 0.3 m, tread of 0.29 m, width of 1 m). The 3-dimensional cinematography and ground reaction force were also utilized for analysis of leg stiffness: Peak vertical force, change in stance phase leg length, Torque of whole body, kinematic variables. The strategy heightened the leg stiffness and standardized vertical ground reaction force relative to the added weights (p<.01). Torque showed rather larger rotational force in case of no load, but less in 10% of body weight (p<.05). Similarly angle of hip joint showed most extended in no-load, but most flexed in 10% of body weight (p<.05). Inclined angle of body trunk showed largest range in posterior direction in no-load, but in vertical line nearly relative to added weights (p<.001). Thus the result of the study proved that downward stepping strategy altered from height of 30 cm, regardless of added weight, did not affect velocity and length of lower leg. But added weight contributed to more vertical impulse force and increase of rigidity of whole body than forward rotational torque under condition of altered stepping strategy. In future study, the experimental on effect of weight change and alteration of downward stepping strategy using ankle joint may provide helpful information for development of enhanced program of prevention and rehabilitation on motor performance and injury.

• 동의신경정신과학회지
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• 제31권4호
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• pp.225-233
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• 2020

Objectives: This study aimed to reveal the gait characteristics of each Sasang constitution by examining the differences in gait analysis indicators using a 3-axis accelerometer. Methods: Ninety-one participants were classified through the TS-QSCD (Two-Step Questionnaire for Sasang Constitution Diagnosis) method and gait analysis was performed using a 3-Axis Accelerometer (G-WALK. BTS Bioengineering, Italy). Gait analysis in returning to the 6-meter turnaround point and 6-minute walking test were performed. The differences in the gait analysis index values were analyzed between each constitution. Results: The gait analysis of 91 subjects (37 Taeumin, 37 Soyangin, and 17 Soeumin), showed that the percent stride length/height in the Soyangin subjects was significantly higher than that of the Taeeumin and Soeuminin subjects in the spatiotemporal walking variables (p<0.05). Stride length also showed the widest tendency in the Soyangin subjects (p=0.05). In the kinesiological analysis, the range of pelvic obliquity angles in the Soeumin subjects was significantly wider than that of the Taeumin and Soyangin subjects (p<0.05). In the six-minute walking test, the Soyangin subjects walked the farthest at 309.41±35.23 m (p=0.064). Conclusions: In a comparison of the gait characteristics for each Sasang constitution using a three-dimensional accelerometer, the stride width of the Soyangin subjects was the widest compared to the Taeeumin, and Soeumin subjects, and Soyangin's walking speed showed a faster tendency than that of the Taeeumin and Soeumin subjects.

• Journal of Ecology and Environment
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• 제45권4호
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• pp.163-169
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• 2021

Background: Understanding the habitat characteristics of the endangered Siberian flying squirrel Pteromys volans is the first step in conserving and managing the forests it requires for nesting, gliding, and feeding. Therefore, in the present study, we characterized the habitats of P. volans using GIS analysis of 411 forest sites in South Korea where fecal droppings were found. Results: Fecal signs of P. volans were found in various regions in South Korea, including the Baekdudaegan Mountains. GIS analysis with six environmental layers (vegetation type, wood-age class, diameter at breast height [DBH], crown density, elevation, and distance from stream) revealed that fecal signs of P. volans were more frequently found in broad-leaved deciduous forests (42%) located 200-399 m above sea level (43.1%) and 0-199 m from the nearest stream (53%), with 5th class wood-age (35.3%), middle size class DBH (51.1%), and high crown density (71%). Conclusions: The present study provides information on the biotic and abiotic characteristics of P. volans habitats. In South Korea, the fecal droppings of P. volans were found predominantly old deciduous broadleaf forests. Further studies are needed to reveal whether the more frequent occurrence of P. volans dropping in broadleaf forests may be due to a particular preference of this species for the forests or to a simple reflection of the area of the broadleaf forests occupying a much larger area than other forest types in Korea.

• 한국운동역학회지
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• 제32권4호
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• pp.111-120
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• 2022

Objective: This study investigated the effect of pelvic tiltng according to the paralytic side on gait in stroke patients during a 10 m functional movement timed up and go (TUG) test. Method: In this study, gait parameters were measured using a gait analyzer for 20 stroke patients and their gait was analyzed during a 10 m TUG test. For statistical analysis, an independent sample t-test were performed for age, height, and weight among general characteristics of subjects and homogeneity was tested by performing a chi-square test for gender, paralysis side, period of onset, and K-MMSE score. In order to understand the relationship between each variable, Pearson correlation analysis was performed on the variables. Results: First, the right-hand paralyzed group showed correlations in cadence and gait velocity in the up and down tilt of the pelvis, and the left-hand paralyzed group showed correlations in cadence and step length in the anterior and posterior tilt of the pelvis. Second, the tilt of the pelvis was correlated with the Sit to stand, walk forward, walk backwards, turn around at the end point, sit on a chair and the total TUG time in the right hemiplegic group compared to the left hemiplegic group. Conclusion: In this study, a significant correlation was confirmed as a result of gait analysis of right-handed stroke patients divided into a right paraplegic group and a left paraplegic group. In the future, it is suggested that treatment for improving gait of stroke patients should be treated differently for the right and left paralyzed side.

• 로봇학회논문지
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• 제16권4호
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• pp.336-344
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• 2021

This paper presents a robust deep learning-based human tracking framework in crowded environments. For practical human tracking applications, a target must be robustly tracked even in undetected or overcrowded situations. The proposed framework consists of two parts: robust deep learning-based human detection and tracking while recognizing the aforementioned situations. In the former part, target candidates are detected using Detectron2, which is one of the powerful deep learning tools, and their weights are computed and assigned. Subsequently, a candidate with the highest weight is extracted and is utilized to track the target human using a Kalman filter. If the bounding boxes of the extracted candidate and another candidate are overlapped, it is regarded as a crowded situation. In this situation, the center information of the extracted candidate is compensated using the state estimated prior to the crowded situation. When candidates are not detected from Detectron2, it means that the target is completely occluded and the next state of the target is estimated using the Kalman prediction step only. In two experiments, people wearing the same color clothes and having a similar height roam around the given place by overlapping one another. The average error of the proposed framework was measured and compared with one of the conventional approaches. In the error result, the proposed framework showed its robustness in the crowded environments.