• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.363-363
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• 2011

열분해 반응기 내에서 실리콘 필름을 성장시키는 것은 반도체/디스플레이, 태양전지, 신소재 등 다양한 분야에서 중요한 공정이다. 더욱이 반도체 소자 선폭이 줄어들면서 나노입자의 오염 제어가 더불어 중요해지고 있다. 생산 공정 기술의 집적화에 따라 패턴 사이 거리가 작아지고, 이에 불과 수 십 나노미터크기의 오염입자에 의해서 패턴불량이 발생하고 생산수율을 감소시킨다. 일반적으로 반도체 공정 중 발생한 오염입자는 반응기 내의 가스가 물리/화학적 공정에 의해 핵생성(nucleation)이 일어나 핵(nuclei)이 생성되고, 이 때 표면반응 및 응집(coagulation)에 의해 성장하게 된다. 이에 본 연구에서는 열분해 반응기 내에서 사일렌(SiH4) 가스를 열분해하여 발생되는 실리콘 오염입자의 핵생성과 성장 모델을 정립하고, 생성된 오염입자의 거동과 전달 현상을 이론적으로 고찰하였다. 열분해 반응기와 같은 기상공정(Gas to particle conversion)에서 오염입자가 생성될 때, 그 성질과 크기 등에 물리/화학적 영향을 주는 요소는 전구체/이송기체의 농도 및 유량, 작동 압력, 작동 온도와 반응기 고유 특성 등이 있다. 수치해석의 정당성과 빠른 계산을 위해 단순화시킨 0D 모델인 Batch 반응기와 1D모델인 plug flow 반응기 등에서 SiH4 가스의 열분해 과정시 생성되는 Si cluster를 상용코드인 CHEMKIN 4.1.1을 이용하여 계산하였으며, 2D모델인 Shear flow 반응기로 확장시켜 Si 오염입자가 생성특성을 연구하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.186-186
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• 2010

액정디스플레이, 유기발광소자 및 태양전지에서 전도성 투명전극으로 indium-tin-oxide (ITO)가 일반적으로 많이 사용되고 있지만 인듐의 희소성과 유독성으로 인하여 ITO를 대체할 수 있는 물질에 대한 많은 연구가 현재 진행되고 있다. ITO 전극을 대체할 수 있는 물질 중에서 Al 도핑된 ZnO (AZO) 박막은 높은 전도성과 광학적 투과성 때문에 다양한 광전소자의 전극과 윈도우 물질로 많은 응용 가능성을 보여주고 있다. 본 연구에서는 여러 가지 스퍼터링 증착 조건에서 증착된 AZO 박막의 전기적특성과 광학적 특성을 조사하였다. 기준시료의 AZO 박막 증착 조건은 ZnO-2 wt.% $Al_2O_3$세라믹 타겟을 사용하였고 $250^{\circ}C$의 기판 온도에서 100 W 전력으로 5 mTorr의 진공 분위기에서 증착되었다. 최적의 AZO 박막 조건을 얻기 위해 증착 온도와 증착 챔버의 압력을 변화하면서 AZO 박막의 전기적 특성 변화와 광학적 특성 변화를 조사하였다. 4-포인트 프로브 측정과 홀 효과측정으로 각기 다른 조건에서 증착한 AZO 박막의 비저항과 전하농도 값을 비교 분석하였고 UV 스펙트로미터 측정을 통해서 AZO 박막의 투과율을 조사하였다. 스퍼터링 방법으로 증착된 AZO 박막은 높은 전도성과 광학적 투과성을 가지기 때문에 액정디스플레이, 유기발광소자 및 태양전지의 투명전극으로 사용할 수 있음을 알 수 있었다.

• Korean Journal of Labor Studies
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• v.14 no.2
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• pp.347-375
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• 2008

영국지방정부 노사관계는 중앙집권적인 구도 속에도 개별 지방정부 차원에서의 자율이 허용되는 일종의 조정된 분권화의 모습을 보였다. 하지만 1980년대부터의 시장메커니즘의 도입 이후 일부 지방정부는 중앙의 현실인식부족을 강조하면서 중앙차원의 교섭구도에서 탈피하게 된다. 1997년의 교섭구도의 통합화 이후 보다 조정된 형태로의 변화를 기대했으나, 지부차원에서의 교섭자율화는 그대로 유지되었다. 하지만 중앙교섭의 영향력은 여전히 건재하며 이러한 측면에서 우리는 일종의 중앙과 지방의 상호결합이 나타나고 있다고 정의할 수 있다. 그동안 축적된 조직력과 경험이 이를 가능하게 했다고 보여진다. 또 다른 변화는 노사 파트너십의 도입인데 노동조합도 자신들의 입지 약화를 인정하면서 이러한 변화에 대해 긍정적인 입장이고, 더 이상 과거와 같은 대립적인 관계는 자신들에게 유리할 것이 없다는 인식이 확산되는 상황에서 점차적으로 파트너십의 관행이 영국 내 자리 잡을 것으로 기대된다. 여전히 중앙의 영향력이 있기는 하지만 분권화와 같은 변화는 현장 차원에서의 파트너십을 용이하게 할 수 있는 제도이기 때문이다. 결국 지방정부의 노사관계는 기존의 고도의 현대화의 하나인 제도적인 형태에서 철저한 성과압력 및 하위단계로의 권한 위임 등을 동반한 고도의 온정적인 모습 그리고 고도의 현대화의 또 다른 형태이자 보다 유연한 모습인 협의에 근거한 일종의 파트너십 등이 동시에 사용되어지는 다양하고 복잡한 모습으로 변해가고 있다고 정의할 수 있다.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.530-534
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• 2002

Background: In aortic surgery, division and ligation of the left brachiocephalic vein(LBV) may improve exposure of the aortic arch but controversy continues about the safety of this division and whether a divided vein should be reanastomosed after arch replacement was completed. The safety of LBV division and the fate of the left subclavian venous drainage after LBV division were studied. Material and Method: From November 1998 to January 2001, planned division and ligation of the LBV on the mid-line after median sternotomy was peformed in 10 patients during the aortic surgery with the consideration of local anatomy and distal aortic anastomosis. Assessment for upper extremity edema and neurologic symptoms, measurement of venous pressure in the right atrium and left internal jugular vein, and digital subtraction venography(DSV) of the left arm were made postoperatively. Result: In 10 patients there was improvement in access to the aortic arch for procedures on the ascending aorta or aortic arch. The mean age of patients was 62 years(range 24 to 70). Follow-up ranged from 3 weeks to 13 months. One patient died because of mediastinitis from methicilline-resistant staphylococcus aureus strain. All patients had edema on the left upper extremity, but resolved by the postoperative day 4. No patient had any residual edema or difficulty in using the left upper extremity during the entire follow-up period. No patient had postoperative stroke. Pressure difference between the right atrium and left internal jugular vein was peaked on the immediate postoperative period(mean peak pressure difference = 25mmHg), but gradually decreased, then plated by the postoperative day 4. In all DSV studies left subclavian vein flowed across the midline through the inferior thyroid venous plexus. Conclusion: We conclude that division of LBV is safe and reanastomosis is not necessary if inferior thyroid vein, which is developed as a main bridge connecting the left subclavian vein with right venous system, is preserved.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.389-394
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• 1987

The electrical conductivity of CeO$_2$ has been measured in the temperature range of 300 to 1000${\circ}$C under the oxygen pressures of 10$^{-5}$ to 10$^{-1}$ atm. Plots of log ${\sigma}$ vs. 1/T at constant PO$_2$ are found to be linear with an inflection, and the activation energy obtained from the slopes appears to be 2.16 eV for the intrinsic region. The conductivity dependences on PO$_2$ at the above temperature range are closely approximated by ${\sigma}$ ${\alpha}$PO$_2^{-1/4}$ for the intrinsic and ${\sigma}$ ${\alpha}$PO$_2^{-1/6.2}$ for the extrinsic, respectively. The dominant defects in this sample are believed to be Ce$^{3{\cdot}}$ interstitial for the intrinsic and the (Vo-2e') for the extrinsic range. The interpretations of conductivity dependences on temperature and $PO_2$ are presented, and conduction mechanisms are proposed to explain the data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.546-551
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• 2020

Generally, surface vessels have many compartments for operation and living quarters, and each compartment is an important space for the ship's survivability. During ship construction, a compartment leak test is necessary and is carried out on each vessel. However, the current test method is in doubt when looking at the actual test results. The reason is that only one pressure gauge is used for the measurement to check the air, so an uncomprehended phenomenon is detected during group compartment leak tests. From this point of view, an improved test device and method are needed. In this study, a multi-channel data acquisition device with multiple pressure sensors is proposed to detect each compartment's pressure variation or pressure drop. This test is a more confidential compartment leak test than the current method, and the test device can show real-time pressure detection values of each of the pressure sensors, which are installed in each compartment, including unmanned space.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.128-133
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• 2010

ZnO:Al films were deposited by DC-pulsed magnetron sputtering using a two-step process involving the control of the oxygen pressure. The seed layers were prepared with various Ar to oxygen flow ratios and the bulk layers were deposited under pure Ar. As the oxygen pressure during the deposition of the seed layer increased, the crystallinity and degree of (002) texturing increased. The resistivity gradually decreased with increasing crystallinity from $4.7\times10^4\Omega{\cdot}cm$ (no seed) to $3.7\times10^4\Omega{\cdot}cm$ (Ar/$O_2$ = 9/1). The etched surface showed a crater-like structure and an abrupt morphology change appeared as the crystallinity was increased. The sample deposited at an Ar/$O_2$ flow ratio of 9/1 showed a very high haze value of 88% at 500 nm, which was explained by the large feature size of the craters, as shown in the AFM image.

• Tunnel and Underground Space
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• v.29 no.3
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• pp.197-213
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• 2019

We simulated the fault reactivation experiment conducted at 'Main Fault' intersecting the low permeability clay formations of Mont Terri Underground Research Laboratory in Switzerland using TOUGH-FLAC simulator. The fluid flow along a fault was modelled with solid elements and governed by Darcy's law with the cubic law in TOUGH2, whereas the mechanical behavior of a single fault was represented by creating interface elements between two separating rock blocks in FLAC3D. We formulate the hydro-mechanical coupling relation of hydraulic aperture to consider the elastic fracture opening and failure-induced dilation for reproducing the abrupt changes in injection flow rate and monitoring pressure at fracture opening pressure. A parametric study was conducted to examine the effects of in-situ stress condition and fault deformation and strength parameters and to find the optimal parameter set to reproduce the field observations. In the best matching simulation, the fracture opening pressure and variations of injection flow rate and monitoring pressure showed good agreement with field experiment results, which suggests the capability of the numerical model to reasonably capture the fracture opening and propagation process. The model overestimated the fault displacement in shear direction and the range of reactivated zone, which was attributed to the progressive shear failures along the fault at high injection pressure. In the field experiment results, however, fracture tensile opening seems the dominant mechanism affecting the hydraulic aperture increase.

• Journal of the Korea Society of Computer and Information
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• v.27 no.2
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• pp.153-161
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• 2022

Physical activities are decreasing and sitting time is increasing due to the automation, smartization, and intelligence of necessary household items throughout daily life. Recent healthcare studies have reported that the likelihood of obesity, diabetes, cardiovascular disease, and early death increases in proportion to sitting time. In this paper, we develop a sitting posture correction cushion in real time using capacitive pressure sensor based on conductive textile. It develops a pressure sensor using conductive textile, a key component of the posture correction cushion, and develops a low power-based pressure measurement circuit. It provides a function to transmit sensor values measured in real time to smartphones using BLE short-range wireless communication on the posture correction cushion, and develops a mobile application to check the condition of the sitting posture through these sensor values. In the mobile app, you can visualize your sitting posture and check it in real time, and if you keep it in the wrong posture for a certain period of time, you can notify it through an alarm. In addition, it is possible to visualize the sitting time and posture accuracy in a graph. Through the correction cushion in this paper, we experiment with how effective it is to correct the user's posture by recognizing the user's sitting posture, and present differentiation and excellence compared to other product.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.32-39
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• 2014

To ensure the reliability of the safety system so that handing large quantities of hazardous materials in chemical plant is considered basic information in chemical process design. However, the reliability of the production system may be reduced when the reliability of the safety system emphasized in order to ensure the safety of chemical process. It is necessary to balance the reliability of the production system and reliability of the safety. In this study, a quantitative risk assessment was performed by selecting the furnace process, which is widely used in the chemical plant in order to suggest a way to ensure the safety and productivity of chemical process, based on the quantitative data. Quantitative risk assessment methodology have been used directed graph analysis methodology. It is possible to evaluate the reliability of the safety system and the production system. In this study, the optimum system design requirement to improve the safety and the productivity of the furnace is two-out-of-three logic for TT and PT.