• 한국전기전자재료학회논문지
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• 제14권9호
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• pp.707-713
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• 2001

As the integrated circuit device shrinks to smaller dimensions, chemical mechanical polishing (CMP) process was requirdfo the global planarization of inter-metal dielectric (IMD) layer with free-defect. However, as the IMD layer gest thinner, micro-scratches are becoming as major defects. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Micro-scratches are generated by agglomerated slurry, solidified and attached slurry in pipe line of slurry supply system. To prevent agglomerated slurry particle from inflow, we installed 0.5${\mu}{\textrm}{m}$ point of use (POU) filter, which is depth-type filter and has 80% filtering efficiency for the 1.0${\mu}{\textrm}{m}$ size particle. In this paper, we studied the relationship between defect generation and polished wafer counts to understand the exact efficiency fo the slurry filteration, and to find out the appropriate pad usage. Our experimental results showed that it sis impossible to prevent defect-causing particles perfectly through the depth-type filter. Thus, we suggest that it is necessary to optimize the slurry flow rate, and to install the high spray bar of de-ionized water (DIW) with high pressure, to overcome the weak-point of depth type filter.

• Journal of Chest Surgery
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• 제23권3호
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• pp.430-437
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• 1990

We clinically evaluated 121 cases of ventricular septal defect which we operated from April, 1986 to December, 1989 at Inha General Hospital, Seong-Nam, Department of Thoracic and Cardiovascular Surgery, College of Medicine, Inha University. These patients were occupied 54.8% of all congenital heart diseases operated on its same period. Of the 121 patients, 63 patients were male[52.1%] and 58 patients were female[47.9i]. The two most common symptoms were frequent upper respiratory infection and dyspnea on exertion. By Kirklin s anatomical classification, type I constituted 34.7%, type II 61.98%, type III 0.03% and type IV not occupied. Associated cardiac anomalies were found in 34 cases, and PDA was most common associated anomaly, occupied in 22 cases. On the cardiac catheterization data, there were statistically significant correlation between VSD size[cm2 /BSAm2] and systolic pulmonary arterial pressure[sPAP], pulmonary to systemic flow ratio[Qp/Qs] & pulmonary to systemic pressure ratio[Pp/Ps] respectively, Type II [r=0.53, p<0.01] was more correlated than type I [r=0.49, p<0.05] between VSD size and Qp /Qs. We could not found the correlationship between age and Qp/Qs [Type I; r=0.16, Type II; r=-0.15] All cases were operated under cardiopulmonary bypass and 58 cases[46.3%] were operated through the right atrial approach, and 34 cases[28.1%] through the pulmonary arterial approach. Operative mortality rate was 4.13%[5 cases].

• Journal of Chest Surgery
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• 제32권9호
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• pp.823-826
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• 1999

주대동맥폐동맥간 부행혈관, 심실중격결손과 폐동맥 형성부전이 동반된 6개월된 환아에서 Clamshell 절개 를 통한 일차 완전교정술을 시행하였다. 수술 후 특별한 합병증은 없었으며, 초음파 검사상 남아있는 심실중 격결손이나 의미있는 폐동맥 협착 소견을 보이지 않았다. 이러한 질환의 수술적 접근에 \ulcorner폐로 공급되는 혈 류의 형태에 따라 다양한 방법이 존재하는데, 최근 들어서는 일차 완전교정술에 대한 여러 형태의 수술방법 이 제시되고 있으며, 그 적용 또한 확대되고 있다. 본 증례의 경우 Clamshell 절개 방법을 적용함으로써 종격 동내 병변에 대한 접근이 용이하였으며, 수술 결과 및 합병증 등의 측면에서도 일차 완전교정술의 한 방법 으로 고려해 볼만하다고 여겨진다.

• 대한전기학회논문지:전력기술부문A
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• 제51권8호
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• pp.379-384
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• 2002

In the competitive electricity market, various pricing methods are developed and practiced in many countries. Among these pricing methods, marginal loss factor(MLF) can be applied to reflect the marginal cost of network losses. For the calculation of MLF, power flow method has been used to calculate system loss deviation. However, this power flow method shows some shortcomings such as necessity of regional reference node, and absence of an ability to consider network constraints like line congestion, voltage limit, and generation output limit. The former defect might affects adversely to the equity of market participants and the latter might generate an inappropriate price signals to customers and generators. To overcome these defects, the utilization of optimal power flow(OPF) is suggested to get the system loss deviation in this paper. 30-bus system is used for the case study to compare the MLF results by the power flow and the OPF method for 24-hour dispatching and pricing, Generator payment and customer charge are compared with these two methods also. The results show that MLF by OPF reflects the power system condition more faithfully than that of by the conventional power flow method

• 대한기계학회논문집B
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• 제21권5호
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• pp.700-712
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• 1997

The flowfield generated by a 2-D rotating cylinder on a plane moving at freestream velocity was experimentally investigated in a wind tunnel to simulate aerodynamic characteristics of rotating wheels of an automobile. In the flowfield around a rotating cylinder at 3*10$^{3}$ < Re$_{d}$<8*10$^{3}$, unique mean flow and turbulence characteristics were confirmed by hot-wire measurements as well as frequency analysis, which was supported by flow visualization. In the vicinity of a rotating cylinder, a unique turbulence structure on .root.over bar u'$^{2}$ profiles was formed in hump-like shape at 1 < y/d < 3. A peak frequency which characterized the effect of a rotating cylinder had the same value of the rotation rate of a cylinder. In case of cylinder rotation, the depths of mean velocity -defect and turbulent-shear regions were thickened by 20-40% at 0 < x/d < 10 compared with the case of cylinder stationary. Far downstream beyond x/d > 10, the flowfield generated by a rotating cylinder showed self-similarity in the profiles of mean velocity and turbulence quantities. The effect of a rotating cylinder was independent of its rotation rate and Reynolds number in the measurement range.

• 한국해양공학회지
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• 제35권6호
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• pp.403-413
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• 2021

As the size of ships increases, the size and output power of their thrusters also increase. When a large ship berths or unberths, the jet flow produced from its thruster has an adverse effect on the stability of quay walls. In this study, we conducted a numerical analysis to examine the impact of the thruster jet flow of a 30,000 TEU container ship, which is expected to be built in the near future, on the stability of a quay wall. In the numerical simulation, we used the fluid-structure interaction analysis technique of LS-DYNA, which is calculated by the overlapping capability using an arbitrary Lagrangian Eulerian formulation and Euler-Lagrange coupling algorithm with an explicit finite element method. As the ship approached the quay wall and the vertical position of the thruster approached the mound of the quay wall, the jet flow directly affected the foot-protection blocks and armor stones. The movement and separation of the foot-protection blocks and armor stones were confirmed in the area affected directly by the thruster jet flow of the container ship. Therefore, the thruster jet flows of ultra-large ships must be considered when planning and designing ports. In addition, the stability of existing port structures must be evaluated.

• 한국정밀공학회지
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• 제14권9호
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• pp.30-36
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• 1997

In this study, the development of an aluminum forged piston was tried to substitute the cast piston, in which there were internal defects such as blow hole and shrink pipe. A gasoline engine piston was chosen as an example for developing the forged piston. Before aluminum forging, model, material (plasticine) test was carried out to investigate the forgeability and internal flow pattern of the forged piston at room temperature. From the result of model material test, an aluminum piston to be forged was redesigned. The aluminum pistion was forged in hot process. The quality of a forged piston was compared with that of a cast piston in the point of mechanical properties, internal defect and microstructure. It was proved that the forged piston was superior to the cast piston.

• 한국정밀공학회지
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• 제21권1호
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• pp.32-39
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• 2004

Traditional forging of a hollow T-shaped part has been applied to forge a solid T-shaped product from a solid billet and then to machine the hollow in that. In a case, a hollow T-shaped part can be forged by backward-extruding from a solid billet. In this study, four types of forging were suggested for manufacture of hollow T-shaped parts. Forging simulations for each of these forging methods were carried out to investigate folding defect, metal flow pattern, effective strain, and forging loads. Experimental works were carried out to be compared with the simulation results. Here, the ratio of the thickness of the hollow tube to that of the flange was selected to investigate a forging defect like folding.

• 한국임상수의학회지
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• 제21권3호
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• pp.314-318
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• 2004

A 7-month-old 8.2 kg female Siberian Husky with history of exercise intolerance, delayed growth, and tachypnea was presented to Veterinary Medical Teaching Hospital, Kyungpook National University. A holosystolic murmur was identified in cardiac ausculation. In electrocardiography, thoracic radiographs, and ultrasonography, a right axis deviation, enlarged right ventricle, stenotic main pulmonary artery, large ventricular septal defect, marked right ventricle hypertrophy, and overriding aorta with dilation were identified. The color Doppler examination showed the left-to-right shunting of blood via interventricular septal defect and the blood flow streams converging from the right and left ventricles into the aorta. The dog was diagnosed as tetralogy of Fallot. The current state of the dog is well-tolerated without any specific medication.

• 한국세라믹학회지
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• 제44권4호
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• pp.202-207
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• 2007

High-Quality 1-Dimensional InN single crystalline have been grown by Halide Vapor-Phase Epitaxy on the Au catalyst coated Si substrate using the vapor-liquid-solid growth mechanism. We have been grown 1-dimension InN nanowires having controlled the growth conditions for substrate temperature and gases flow rate. The grown InN nanowire of characteristics for morphologies, crystal structure, and element analysis were carried out by SEM, HR-TEM, and EDS respectively. And the defects of InN crystalline were analyzed by indexing of selective area diffraction pattern with attached HR-TEM. We have successfully obtained the defect-free 1-dimensional InN single crystalline nanowire at the atmosphere pressure.