• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.393-399
• /
• 2005

The purpose of this study is to suggest some references of maintenance and design of concrete gravity dams by analyzing dynamic characteristics in x, y, z directions. It is considered as additional mass, soil interaction for numerical dynamic analysis for gravity concrete dams in Han River basin as some cases. The result shows that the overflow structure can be possibly underestimated for the evaluation of the seismic performance using seismic intensity, modified seismic intensity methods. A much more research is still necessary for the evaluation of comprehensive seismic performance of concrete gravity dam

• Journal of Chest Surgery
• /
• v.15 no.2
• /
• pp.169-173
• /
• 1982

We have experienced two cases of complicated teratoma in anterior mediastinum. One case, 1-year-old female, has a huge anterior mediastinal teratoma involving almost all of the left pleural cavity with atelectasis of the left lung. The other case, 12-year-old female, has a anterior mediastinal teratoma with fistula between the teratoma and the bronchus of anteromedial basal segment of left lung. The bronchus has a bronchiectatic change with cell infiltration. We performed exploratory thoracotomy with complete excision of tumor mass in both cases and with additional resection of anteromedial basal segment of the left lung due to inflammation and necrosis in latter case. The patients had uneventful postoperative courses and were discharged in good condition. Histopathologic diagnosis of these were benign teratoma consist of skin, skin appendages, cartilage, connective tissue, and gut.

• Journal of the Korean Vacuum Society
• /
• v.6 no.S1
• /
• pp.59-65
• /
• 1997

Efficient Si(100) etching by thermal H atoms at low substrate temperatures has been achieved. Gas-phase etching product $SiH_4$(g) upon H atom bombardment resulting from direct abstraction of $SiH_3$(a) by impinging H atoms was detected with a quadrupole mass spectrometer over the substrate temperature range of 105-408 K Facile depletion of all surface silyl ($SiH_3$) groups the dissociative adsorption product of disilane ($Si_2H_6$) at 105K from Si(100)2$\times$1 by D atoms and continuous regeneration and removal of $SiD_3$(a) were all consumed. These results provide direct evidence for efficient silicon surface etching by thermal hydrogen bombardment at cryogenic temperatures as low as 105K We attribute the high etching efficiency to the formation and stability of $SiH_3$(a) on Si(100) at lowered surface temperatures allowing the $SiH_3$(a) abstraction reaction by additional H atom to produce $SiH_4$((g).

• Transactions on Electrical and Electronic Materials
• /
• v.12 no.5
• /
• pp.197-199
• /
• 2011

In this paper, the bottom-gate thin-film transistors (TFTs) were fabricated with an amorphous/microcrystalline Si double layer (DL) as an active layer and the variations of the electrical characteristics were investigated according to the DC bias stresses. Since the fabrication process of DL TFTs was identical to that of the conventional amorphous Si (a-Si) TFTs, it creates no additional manufacturing cost. Moreover, the amorphous/microcrystalline Si DL could possibly improve stability and mass production efficiency. Although the field effect mobility of the typical DL TFTs is similar to that of a-Si TFTs, the DL TFTs had a higher reliability with respect to the direct current (DC) bias stresses.

• Journal of the Korean Society of Combustion
• /
• v.23 no.1
• /
• pp.44-54
• /
• 2018

Heat and mass balance process modeling has been conducted for a coal-firing power plant to be used as a testbed facility for development of various plant systems and equipment. As the material and design of the boiler tube bundle and fuel conversion to the biomass have become major concerns, the process modeling is required to incorporate those features in its calculation. The simulation cases for two different generation load show the satisfying results compared to the operational data from the actual system. Based on the established process conditions, the hypothetical case using wood pellet has also been simulated. Additional calculations for the tube bundle has been conducted regarding the changes in the tube material and design.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.2
• /
• pp.644-650
• /
• 2010

In this paper, an experimental study is performed in order to determine the effects of interaction between vehicle and structure. For this purpose a wheel tracking machine and an adequate precast concrete deck single span bridge are designed. Results presented in the paper show that interaction between vehicle and structure produce additional effects on dynamic behavior of structure including reversal and contrary behavior.

• Earthquakes and Structures
• /
• v.12 no.2
• /
• pp.145-152
• /
• 2017

The analytical method is used to develop new models for an elevated tank to estimate its natural period. The equivalent mass- spring method is used to configure the developed analytical models. Also direct method is used for numerical verification. The current study shows that developed models can have a good estimation of natural period compared with concluded results of finite elements. Additional results show that, the dependency of impulsive period to soil stiffness condition is higher than convective period. Furthermore results show that considering the fluid- structure- soil interaction has remarkable effects on natural impulsive and convective periods in case of hard to very soft soil.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.38 no.4
• /
• pp.240-244
• /
• 2012

Myofibroblastic sarcoma is a rare tumor that mostly develops in the soft tissues of the head and neck. Within the oral cavity, a tongue lesion is the most common. A myofibroblastic sarcoma tends to recur locally instead of metastasizing. We encountered a myofibroblastic sarcoma of the mandible of a 9-year-old male and performed mass excision and additional marginal alveolectomy. So far, there is neither recurrence nor metastasis. We report this case because of the uncommon location of this tumor type and its surgical approach compared to other forms of sarcomas.

• 한국전산유체공학회:학술대회논문집
• /
• 2007.10a
• /
• pp.141-148
• /
• 2007

We present an immersed boundary (IB) method for 3D simulation of flappingflags in a uniform flow. The proposed formulation is manipulated on the basis of an efficient Navier-Stokes solver adopting the fractional step method and a staggered Cartesian grid system. A direct numerical method is developed to calculate the flag motion, with the elastic force treated implicitly. The fluid motion defined on an Eulerian grid and the flag motion defined on a Lagrangian grid are independently solved and the mass of flag is handled in a natural way. An additional momentum forcing is formulated from the flag motion equation in a way similar with the direct-forcing IB formulation and acts as the interaction force between the flag and ambient fluid. A series of numerical tests are performed and the present results are compared qualitatively and quantitatively with previous studies. The instantaneous flag motion is analyzed under different conditions and surrounding vortical structures are identified. The effects of physical parameters on the flapping frequency are studied.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.511-516
• /
• 2001

The flow characteristics in a hot mill reheating furnace is numerically simulated in this study. Navier-Stokes equations for conservation of mass, momentum, energy are solved and the standard $k-\varepsilon$ model, mixture fraction/PDF model are used for the turbulent reacting flow in the furnace. Radiation heat transfer is incorporated by the P-1 method with the absorption coefficient evaluated using WSGGM. First, simulation results are obtained for the total furnace region with existing protective dam, and then the calculations are carried out only for the preheating zone in the furnace. In that zone, additional center darn is built in order to control the flow behavior of the inlet air and the combustion gas.