• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.77.1-77.1
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• 2012

Zn 기반 산화물 반도체는 기존의 비정질 Si에 비해 저온공정에도 불구하고 높은 이동도, 투명하다는 장점으로 인해 차세대 디스플레이용 백플레인 소자로 주목받고 있다. 산화물 트랜지스터는 우수한 소자특성을 보여주고 있지만, 온도, 빛, 그리고 게이트 바이어스 스트레스에 의한 문턱전압의 불안정성이 문제의 문제를 해결해야한다. 산화물 반도체의 문턱전압의 불안정성은 유전체와 채널층의 계면 혹은 채널에서의 charge trap, photo-generated carrier, ads-/desorption of molecular 등의 원인으로 보고되고 있어, 고신뢰성의 산화물 채널층을 성장하기 위한 노력이 이루어지고 있다. 최근, 산화물 트랜지스터의 다양한 조건에서의 문턱전압의 불안정성을 해결하기 위해 산화물의 주된 결함으로 일컬어지고 있는 산소결핍을 억제하기 위해 성장공정의 제어 그리고, 산소와의 높은 binding energy를 같은 Al, Hf, Si 등과 같은 원소를 첨가하여 향상된 소자의 특성이 보고되고 있지만, 줄어든 산소공공으로 인해 이동도가 저하되는 문제점이 야기되고 있다. 이러한 문제점을 해결하기 위해, 최근에는 Buried layer의 삽입 혹은 bi-channel 등과 같은 방안들이 제안되고 있다. 본 연구는 atomic layer deposition을 이용하여 AZO bureid layer가 적용된 ZnO 트랜지스터의 특성과 안정성에 대한 연구를 하였다. 다결정 ZnO 채널은 유전체와의 계면에 많은 interface trap density로 인해 positive gate bias stress에 의한 문턱전압의 불안정성을 보였지만, AZO층이 적용된 ZnO 트랜지스터는 줄어든 interface trap density로 인해 향산된 stability를 보였다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.152-158
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• 2006

The objective of this study is to investigate change in diurnal respiration and transpiration of the fruits of kiwifruit during fruit growth. Three-hourly fruit transpiration and respiration rate were measured by a chamber technique. Results showed a tendency of higher transpiration and respiration in at maturation to commercial harvest period in 1995 fruit than in 1996 fruit. Fruit respiration rates were very similar to the transpiration rates. The air temperature record for the fruit maturation period in 1996 showed a sudden drop on September $19{\sim}24$ and October 14 down to $7{\sim}13^{\circ}C$. These results suggest that abnormal fruit transpiration and respiration rate in the fruit maturation period might be influenced by the air temperature.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.330-335
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• 2012

This study performed the structure analysis for development and localization of main and nose wheel in Korean Helicopter Program(KHP). Structural stability of wheel is evaluated using ANSYS. Considering wheel and tire interface, Stress analysis was conducted by applying pneumatic of tire, static load, radial load and combined load on main and nose wheel. Considering yield strength at which plastic deformation occurs, simulation results suggest the method which increases structure stability after comparing maximum stress and yield strength.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.61-73
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• 2002

Daegok dam is Concrete Face Rockfill Dam(C.F.R.D) of which 52m height, 190m length, that construction in beneath 306, Chanjeon-Ri, Dudong-Myeon, Ulju-Gun, Ulsan Metrocity. Left slope excavation of spillway have related to Daegok dam construction are developing crack in Sta. No. 1~2, EL. 134~137m after 67.0mm rainfall from 2000. 7. 23. 13:00 to 7. 24. 04:00. Surface geological survey and slope stability investigation with stereographic projection method in order of slope stability establishment. Partial supplement excavation and SSL. P. C. Anchoring method is able to pre-stressing are think about unstable element after excavation. This slope stability establishment is very successfully completion.

• Journal of Sensor Science and Technology
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• v.21 no.3
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• pp.186-191
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• 2012

In this paper, we present a pH measurement method that uses a microcantilever-array-based biosensor system. It is composed of microcantilever array, liquid cell, micro syringe pump, laser diode array, position sensitive detector, data acquisition device, and data processing software. Four microcantilevers are functionalized with pH-sensitive MHA(mercaptohexadecanoic acid) as a probe, while three microcantilevers are functionalized with HDT(hexadecane thiol) as reference. We prepare PBS(phosphate buffered saline) solutions of different pH and inject them into the liquid cell with a predefined volumetric speed at regular time intervals. The functionalized mircocantilevers in the liquid cell deflect as a self-assembled monolayer on the microcantilever binds with probe molecules in the solution. The difference in deflection between the MHA-covered probe microcantilever and the HDT-covered reference microcantilever was used to compensate for thermal drift. The deflection difference clearly increases with increasing pH in the solution. It was shown that when the pH values of the PBS solutions are high, there were large variations in the deflection of microcantilevers, whereas there were small variations for low pH value. The experimental results show that the microcantilever array functionalized with MHA and HDT can detect pH value with good repeatability.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.237-240
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• 1998

The application of a low calorie sweetener, tagatose, to chocolate product was investigated. The viscosity of chocolate prepared with tagatose were almost the same as that of chocolate with sucrose. The melting point and endothermic enthalpy of chocolate prepared with tagatose, which were obtained from the analysis of differential scanning calorimetry, were also almost the same as those of chocolate with sucrose. However, chocolate with tagatose was softer than that of chocolate with sucrose.

• The Journal of Korean Medicine
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• v.24 no.3
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• pp.23-34
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• 2003

Objective : In 2001, the rate of obesity in Korea reached 30.6%. There are many therapeutic ways to reduce body weight, such as low and very low calorie diet, exercise therapy, behavior modification therapy, etc. However, in many cases the patients feel stress under obesity treatment because of starvation. This study was aimed to evaluate the anti-starvation stress effect of Coicis Semen on mice. Methods : First, the mice were divided into 6 groups : Normal (group with no starvation), Control (administrated normal saline 6 times before starting 36 hours starvation), and Samples A, B, C, and D (administrated 0.25, 0.5, 1.0, 3.0 g/kg Coicis Semen respectively 6 times before starting 36 hours starvation). Then the plasma corticosterone level and rectal temperature were measured. The norepinephrine, dopamine, DOPAC (dihydroxy-phenylacetic acid), 5-HT (5-hydroxytryptamine) and 5- HIAA (5-hydroxy-indole-acetic acid) in the hypothalamus were measured by the HPLC method. Result : I. The rectal temperature in Sample group D showed a significant difference (P<0.05) compared with the Control group. 2. The DOPAC in Sample groups A, C and D showed the significant difference (P<0.05) compared with the Control group. Conclusion : It might be recognized that Coicis Semen has an anti-starvation stress effect.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.4
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• pp.373-384
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• 2007

The purpose of this study was to analyse the stress distribution on the craniofacial suture and cranium after application of RME. Twelve years and six months old boy and twenty years old adult male were chosen for taking computed-tomography for FEM. From DICOM visual information, it was processed by 3-dimensional image construction program Mimics 10.01. Hounsfield unit(HU) which shows gray scale of CT image is picked for revealing mechanical properties of each model. The models have been accomplished with various range of physical properties. After applying 5.0 mm expansion, the maxillary complex model was obeserved for analyzing displacement and stress distribution of the model. The amount of transverse expansion of child and adult maxilla is different according to its location. It appears that it decreases gradually with the distance from separation site. In child, maximum compressive stress located broad area in zygomatic buttress department and the ends of frontal process of maxilla, pterygoid plate, and bones surrounding orbit. However, in adult maximum compressive stress was located smaller area and the stres was higher than child.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.271-271
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• 2011

본 논문에서는 W-N 확산 방지막을 각각 다른 질소 유입 조건 (0 sccm, 0.5 sccm, 1 sccm) 하에 Si (Silicon) (100) 기판 위에 rf (radio-frequency) magnetron sputter를 이용하여 증착하였다. 증착된 박막은 800$^{\circ}C$에서 열처리하였고, 이때 각각의 W-N 확산 방지 막의 열적 안정성을 분석하였다. 기존 W-N박막의 분석은 X-ray diffraction (XRD)와 같은 분광학적 방법을 사용하여 분석하였으나, 이는 점점 미세화 되어가는 반도체 산업의 최근 동향에는 적합하지 않다. 따라서 이번 실험에서는 박막 국부적인 영역에서 nano scale의 분석이 가능한 nano indentation을 이용하여 분석하였다. 본 연구에서는 열적 안정성을 분석하기 위하여 각각 열처리 온도가 다른 박막의 stress 분포를 XRD와 AFM를 이용하여 구한 격자상수로 먼저 박막 전체적인 영역을 분석하였다. 박막의 국부적인 영역은 앞서 언급하였던 nano indentation을 이용하여 stress 분포를 분석하였다. 실험 결과, 표면의 RMS roughness는 3.6에서 1.4 nm으로 변하였으며, 박막은 미열처리에서 열처리 온도의 증가 시 보다 tensile stress를 많이 받는 것으로 분석하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.133-141
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• 2006

The Low cycle fatigue behavior of 11.7Cr-1.1Mo heat-resisting steel has been investigated under strain-controlled conditions with mean stresses at room temperature and $300^{\circ}C$. For the tensile mean stress test, the initial high tensile mean stress generally relaxed to zero at room temperature, however, at $300^{\circ}C$ initial tensile mean stress relaxed to compressive mean stress. Low cycle fatigue lives under mean stress conditions are usually correlated using modifications to the strain-life approach. Based on the fatigue test results from different stain ratio of -1, 0, 0.5, and 0.75 at room temperature and $300^{\circ}C$, the fatigue damage of the steel was represented by using cyclic strain energy density. Total strain energy density considering mean stress indicated well better than not considering mean stress at $300^{\circ}C$. Predicted fatigue life using Smith-Watson-Topper's parameter correlated fairly well with the experimental life at $300^{\circ}C$.