• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.4
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• pp.303-314
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• 2004

This study is intended to investigate the geotechnical behavior of jointed mass on tunnel excavation experimentally. Laboratory test were conducted in various conditions of distance from joint to tunnel and in-situ stress ratio ($K_0$). In case, the ground around the tunnel that has the joint angle $90^{\circ}$ generate the greatest influence in crown and far shoulder from joint. If the in-situ stress ratio is low, tangential stress of side wall that is opposite side of the joint is increased more than in crown. Otherwise in case, joint angle $45^{\circ}$, the generated compress stress is found out that left side of the tunnel of near the joint has influence on stability of the tunnel about 3 times than non-jointed rock.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.105-115
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• 1999

P-type의 단결정 실리콘 위에 $1000{\AA}$의 열산화막을 성장시킨후 $5500{\AA}$의 다결정 실리콘으로 증착된 시료를 가지고 $HBr/Cl_2/He-O_2$ 혼합기체로 식각할 때 시료의 식각 특성에 관한 $H_2-O_2$ 기체함량. RF 전력, 압력에 대한 영향을 XPS(X-ray photoelectron Spectroscopy)와 SEM(Scanning Electron Microscopy)으로 조사하였다. $HBr/Cl_2/He-O_2$ 혼합기체로 식각되는 동안 형성된 다결정 실리콘 식각속도는 $H_2-O_2$ 함량 증가에 따라 증가하였으며 식각잔유물은 RF 전력과 압력변화에 의해 영향은 받지 않는 것으로 나타났으며, 다결정 실리콘 측벽에서의 증착속도는 낮은 RF전력과 높은 압력에서 높게 나타났다. 다결정 실리콘 식각 잔유물의 결합에너지는 안정한 $SiO_2$인 열산화막의 경우보다 높으므로 식각 잔유물은 $SiO_{\chi}({\chi}>2)$의 화합결합을 가지는 산화물과 같은 잔유물로 생각된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.189-193
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• 2010

RMA-2, Telemac-2D, River2D 등 기존의 대부분 국내외 상용모형에서는 내부 경계인 하천구조물과 외부 경계인 측벽에서의 경계조건을 활동조건(slip condition)으로 가정하여 흐름장을 계산하였다. 그러나 실제로 벽면에서는 마찰력에 의해 흐름이 존재하지 않는 무활조건(no slip condition)이 물리적으로 타당하다. 따라서 본 연구에서는 내부구조물인 교각이 존재하는 영역에서의 수평 2차원 유속분포를 구하기 위해 천수방정식을 Galerkin법과 Newton-Raphson법에 의해 이산화한 수치모형을 개발하였다. Yulistiyanto 등(1998)이 수치모의 및 수리실험에 사용한 조건을 채택하여 벽면에서의 접선방향 유속이 존재하는 활동조건과 벽면에서 유속이 없는 무활조건을 부여하고 교각을 포함한 수로에서 유속, 수위 및 전단분포를 해석하였다. 활동경계조건을 적용한 경우 교각 표면을 따라 큰 유속이 분포하고 후면에서도 관성력에 의해 흐름방향 유속이 두드러지게 나타났으나 무활조건을 적용한 경우 교각 후면에서 와가 형성되고 후류현상이 두드러지게 나타났다. 무활조건을 적용한 경우 교각 전면부에서는 선수파(bow wave)가 4 cm정도 높게 나타났으며 교각 측면부에서는 2 cm 높게 나타났다. 반면 교각 후면에서는 후류의 영향으로 수면이 2 cm 낮게 분포하였다. 교각부에 작용하는 전단력을 분석한 결과 무활조건을 적용한 경우가 활동조건을 적용한 경우에 비해 최대 6배 높은 전단력이 나타났다.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.1-8
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• 2022

High-density packaging technologies, including Through-Si-Via (TSV) technologies, are considered important in many fields such as IoT (internet of things), 6G/5G (generation) communication, and high-performance computing (HPC). Achieving high integration in two dimensional packaging has confronted with physical limitations, and hence various studies have been performed for the three-dimensional (3D) packaging technologies. In this review, we described about the causes and effects of scallop formation in TSV, the scallop-free etching technique for creating smooth sidewalls, Cu pillar and Cu-SiO₂ hybrid bonding in TSV. These technologies are expected to have effects on the formation of high-quality TSVs and the development of 3D packaging technologies.

• Journal of Animal Environmental Science
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• v.18 no.1
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• pp.1-8
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• 2012

The study was conducted to investigate the effects of climate on indoor environment of a swine house with natural. This study was tested in the beef swine stall at Young-in, Kyung-ki do. The test was experimented for the effect of interior environment by the outdoor environment and the interior-pan. The results are as follows. 1. In test 1 ($T_{out}$ : $25.7^{\circ}C$, without fan), an indoor air flow pattern was showed that entered from sidewall winch-curtain to went out of a indoor by the ridge winch-curtain. And the velocity of a section of the center was measured two times as large as the velocity of the floor. It is the acceleration of the velocity by thermal buoyancy. And, the entered air was rapidly dissipated by flow energy. So that in the swain livestock with sidewall winch-curtain is effected by thermal buoyancy. And the air temperature of the indoor was distributed more higher as compared with the outdoor temperature. This result is caused by the sensible heat from swine and the ventilation is restricted. 2. In test 2 (($T_{out}$ : $25.7^{\circ}C$, with fan), the velocity of a section of the center was measured more higher as compared with the test 1. And the variance of air velocity was distributed higher as compared with the test 1. This result is showed dead region of air flow with a fan operation. And, the variance of gas density was distributed lower as compared with the test 1.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.721-728
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• 2004

Velopharyngeal closure is a sphincter mechanism between the activities of the soft palate, lateral pharyngeal wall and the posterior pharyngeal wall, which divides the oral and nasal cavity. It participates in physiological activities such as swallowing, breathing and speech. It is called a velopharyngeal dysfunction when this mechanism malfunctions. The causes of this dysfunction are defects in (1) length, function, posture of the soft palate, (2) depth and width of the nasopharynx and (3) activity of the posterior and lateral pharyngeal wall. The purposes of this study are to analyze the nasopharynx of cleft palate patients using cephalometry and to evaluate the degree of hypernasality using nasometry to find its relationship with velopharyngeal dysfunction. The following results were obtained : 1. In cephalometry, there were significant differences in soft palate length, soft palate thickness, nasopharyngeal depth, nasopharyngeal area, and adequate ratio between two groups. 2. In nasometry, there were significant differences between two groups in vowel /o/ and sentences including oral consonants. 3. In cleft palate patients, though no general correlation was found between Anatomic VPI and nasalance scores, vowel /i/ and sentences including oral consonants were slightly correlated. In conclusion, cephalometry and nasometer results were significantly different between the two groups. Though in the cleft palate group, Anatomic VPI and nasalance scores, which are indices for velopharyngeal closure, excluding the vowel /i/ and sentences including oral consonants show generally no significance.

• Journal of the Korean GEO-environmental Society
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• v.9 no.4
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• pp.5-13
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• 2008

Just as infill material can reduce the shear strength of a rock joint, a layer of soft material between concrete and the surrounding rock socket can reduce pile shaft resistance of drilled shafts socketed in rocks. This can also result from construction methods that leave smeared or remoulded rock or drilling fluid residue on the sides of the rock sockets after concrete placement. The nature of the interface between the concrete pile shaft and the surrounding rock is critically important to the performance of the pile, and is heavily influenced by construction practice. Characteristics of the concrete-rock interface, such as roughness and the presence of the soft materials deposited during or after construction can significantly affect the shaft resistance response of the pile. In this study, we conducted the parametric study to examine the performance characteristics of drilled shafts socketed in smeared rock under the vertical load with the code of finite difference method of FLAC 2D. As the results of the current research, the parameters that affect the settlement of the pile head and the ultimate unit shaft resistance could be identified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3578-3582
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• 2010

The nitrogen oxidized substance(NOx) from cars in city is one of serious air-polution problems. In advanced country, the powder or the liquid photocatalystic for asphalt pavement and noise barrier have been used to reduce the air-polution. In this paper, the effect of photocatalystic on asphalt pavement has been evaluated, especially for UV optical science reactions analyzed NOx purification efficiencies of the automobile waste gas. Judging from the limited lab-scale test, the use of the powder or the liquid photocatalystic is one of alternatives to reduce the NOx from automobile.

• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.251-256
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• 2013

This paper is mainly concerned with the ship-bank interaction by model test. The experiments for the characteristics of hydrodynamic interaction forces and moments between vessel and bank with a mound were carried out in the seakeeping and maneuvering basin. A series of tests were carried out with ship model in parallel course along a vertical sidewall with a mound with varying lateral spacing between model ship and sidewall, length of sidewall and water depth. From the experimental results, it indicated that the hydrodynamic interaction effects increase as length of sidewall with a mound increases. Furthermore, for lateral spacing less than about 0.2L between vessel and bank, it can be concluded that the bank effects increase largely as the lateral spacing between vessel and bank decreases. However, for spacing between vessel and bank more than about 0.3L, the interaction effects increase slowly as lateral spacing decreases. Also, for the water depth to draft ratio(h/d) less than about 1.5, the hydrodynamic interaction effects increase dramatically as h/d decreases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7964-7970
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• 2015

In enclosed areas such as railway tunnels, the heat and smoke generated by a fire can pose a tremendous risk to the life of passengers. To prevent or mitigate such scenarios, fire detectors are installed for early fire detection. This numerical study is preformed for establishing the method of detecting performance of fire detectors installed on railway tunnels. Numerical analysis are conducted using the fire dynamics simulator, developed by the NIST. The temperature of the tunnel walls is determined using the assumed exterior structure of the tunnel. In addition, the detection times of detectors installed at different locations in the tunnel are obtained for different sizes of the fire source, and the results are compared and analyzed.