• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.455-458
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• 2006

This study has numerically modelled the combustion processes of the turbulent swirling premixed lifted flames in the low-swirl burner (LSB). In these turbulent swirling premixed flames, the four tangentially- injected air jets induce the turbulent swirling flow which plays the crucial role to stabilize the turbulent lifted flame. In the present approach, the turbulence-chemistry interaction is represented by the level-set based flame let model. Two-dimensional and three-dimensional computations are made for the various swirl numbers and nozzle length. In terms of the centerline velocity profiles and flame liftoff heights, numerical results are compared with experimental data The three-dimensional approach yields the much better conformity with agreements with measurements without any analytic assumptions on the inlet swirl profiles, compared to the two-dimensional approach. Numerical clearly results indicate that the present level-set based flamelet approach has realistically simulated the structure and stabilization mechanism of the turbulent swirling stoichiometric and lean-premixed lifted flames in the low-swirl burner.

• Biomolecules & Therapeutics
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• 제10권3호
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• pp.202-207
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• 2002

The hepato-protective activity of the GODEX (Hepadif-s capsule) has been studied in the rats against $CCl_4$-ethanol induced liver toxicity. The rats were oral1y treated with $CCl_4$ (corn oil/ $CCl_4$ 1:1, 1 mg/kg). And one week passes, $CCl_4$(0.4 mg/kg) administered two times a week for 7 weeks. The drugs have been administered every two days for 4 weeks after $CCl_4$ injection. The experimental groups have consisted of the GODEX (250 mg/kg), Hepadif (200 mg/kg), DDB complex (DDB 50 mg/kg and garlic oil powder 50 mg/kg), DDB (50 mg/kg), and vehicle control respectively. There was a significant decrement on the serum level of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and total bilirubin in all treated groups. Specially, ALT level of GODEX and Hepadif only treated groups was decreased c1early. Also, serum albumin level was significantly enhanced in GODEX treated group compared with control and DDB treated groups. In histological results, hepatocellular vacuolar degeneration, lobular restructure and necrosis of bile duct were severely showed in control. But other treated groups showed centerilobular degeneration and mild hyper-plasia. Hepadif or DDB has a effects of the recovery on serum parameters and structure ill liver injury. When it was compared GODEX to Hepadif alone or DDB complex or DDB, it suggested to have the best activity of the liver recovery.

• Journal of Information Technology Applications and Management
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• 제17권2호
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• pp.19-45
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• 2010

This research has analyzed the differentiated influence of organizational variables(an organization's learning culture and organizational support networks) and personal variables(the individual's motivation to learn and self-efficacy) on the process of gaining and using of knowledge. These two variables have been regarded as the major variables for the successful learning of 6Sigma, according to Social Cognitive Theory. In addition, this research has proven the role structure of the abovementioned two variables through a suitable methodology(Hierarchical Linear Model). In regard to this methodology, the different hierarchical level of the personal variable and organizational variable was especially focused on, and the effect of interaction between the high level and the low level was considered in detail. Considering the current situation, in that the importance of organizational factor and personal factor has been emphasized but the accurate role of each variable has not been verified, the research model is thought to help to establish an effective strategy to implement 6 Sigma.

• 대한화학회지
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• 제56권4호
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• pp.518-529
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• 2012

이 연구에서는 중학교 '과학2' 교과서에 서술되어 있는 '원소', '주기율표', '원자'에 대한 내용이 요구하는 인지 요구도를 분석하였다. 우리나라는 2007년 개정 교육과정에 의하여 처음으로 주기율표 및 그와 관련 내용들을 중학교에서 다루게 되어있다. 분석에 활용한 6종 과학 교과서에 서술된 내용이 어떠한 인지 수준을 요구하는 지를 알아내는 분석틀은 영국에서 개발된 CAT(Curriculum Analysis Taxonomy)의 3종류 분석틀을 사용하였다. 이 3종류 분석틀에 의하여 분석한 '과학2' 교과서에 서술된 내용이 요구하는 인지 수준들은 다음과 같았다. '원소'에 대한 교과서 서술이 더 이상 간단한 물질로 분리될 수 없는 순물질임을 이해하는 내용으로 후기 형식적 조작 수준이었다. 그러나 '원소'는 한 가지 종류의 원자만으로 이루어진 물질이라고 서술된 초기 형식적 조작 수준도 있었다. '주기율표'에 대한 교과서 서술이 다양한 종류의 원소들을 원소 기호를 이용하여 특정 기준에 따라 몇 가지 그룹으로 분류될 수 있음을 이해해야 하고, 실체를 범주화하는데 있어서 여러 기준으로 분류해야 하는 내용으로 후기 구체적 조작 수준이었다. '주기율표'를 여러 족들의 집함임을 알고 이원 분류표로 이해해야 하는 내용으로 초기 형식적 조작수준이었다. '원자' 구조와 연결 짓는 복합적 분류 체계로 주기율표를 표현하는 후기 형식적 수준도 있었다. '원자'에 대한 교과서 서술이 원자가 구조를 가진다는 것 그리고 원자가 같은 종류도 있고 다른 종류도 있다는 서술은 초기 형식적 수준이었다.

• 대한간호학회지
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• 제23권4호
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• pp.602-616
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• 1993

The purpose of this study was to explore the degree of stress in caregivers caring for patients who had had a cerebro vascular accident as the stress is related to the self- care ability of the patient. The subjects for the study were caregivers of 111 CVA patients, hospitalized at two University affiliated hospitals and two general hospitals in Daejon. The survey instruments used in the study were Kang’s ADL Check List and a modified form of Lee’s Stress Inventory. The survey was conducted from July 16th to August 30th, 1992. The survey results were analyzed using the Statisitical Package for Social Sciences (SPSS) and can be sumerized as follows: 1. The level of self- care for the CVA patients was : 1) complete dependence (M=34.7, 31.2%), 2) complete independence (M=14.8. 13.3%), 3) in-complete independence ( M=17.5, 15.8% ), 4) in-complete dependence (M=14.8, 13.3%) and 5) dependence and independence (M=14.1, 12.7%). The items for which there was a high level of self-care were 1) drinking (M=3.640), 2) returning (M=2.351) and 3) eating (M=2.351) : and the items for which there was a low level of self -care were : 1) ascending and descending stairs (M=2.351), 2) dressing and undressing trousers (M=2.514) and 3) dressing and undressing jacket (M :2.532). 2. There was a statistically difference between the paralytic status and the level of self- care accord-ing to their demographic characteristics ( F=24. 7056, p(.001). 3. There was no significant difference in the degree of caregiver stress according to patient's demo-graphic characteristics. 4. There was a statistically significant difference in the degree of caregiver stress according to the following demographic characteristics : age (F=7.4189, p(.001), education level (F=5.8336, P(.01), family structure (t=2.10, p(.05) and their relationship with the patient (F=6.5099, P〈.01). 5. There was no significant difference in the degree of caregiver stress according to the level of patient self - care.

• 전기학회논문지
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• 제66권10호
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• pp.1532-1539
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• 2017

The floating photovoltaic system is a new concept in the renewable energy technology. That is similar to land based photovoltaic technology except floating system. So the system needs buoyant objects, mooring, ect, besides modules and supports, and that is able to withstand in water level changes and wind strength. Therefore the floating photovoltaic system is much different from land photovoltaic system. K-water (Korea Water Resources Corporation) has been operating two floating photovoltaic system that's capacity is 100 kW and 500 kW respectively since in summer 2011 for commercial generation, and have construction project for 2,000 kW in Boryeong multipurpose Dam and other areas. Furthermore K-water was developing a tracking-type floating photovoltaic system at Daecheong multipurpose Dam and developed and installed an ocean floating photovoltaic demonstration plant at Sihwa Lake in October 2013 for R&D. In this paper, we introduce that structure of floating photovoltaic system include buoyant structure, mooring system and auxiliary device. Especially the rope which is in part of mooring should be always maintain tension under any water level. Also we explain about structure design concept to wind load in an every loading condition and a kind of structure materials and PV structure types used in water environment. Especially ocean floating PV system is affected by tidal current and typhoon. So there are considering the elements in design. Finally we compare with floating and land photovoltaic on power amount. As a result of that we verified the floating photovoltaic system is more about 6.6~14.2 % efficiency than a general land photovoltaic system.

• Structural Engineering and Mechanics
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• 제74권4호
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• pp.567-576
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• 2020

Considerable controversy surrounds the choice of the best abutment type for implant prosthetics. The two most common structures are hex and non-hex abutments. The non-hex abutment typically furnishes a larger contact area between itself and the implant than that provided by a hex structure. However, when a hex abutment is loaded, the position of its contact area may be deeper than that of a non-hex abutment. Hence, the purpose of this study is to determine the different biomechanical behaviors of an internal bone-level implant based on the abutment type-hex or non-hex-and clinical crown length under static and cyclic loadings using finite element analysis (FEA). The hex structure was found to increase the implant and abutment stability more than the nonhex structure among several criteria. The use of the hex structure resulted in a smaller volume of bone tissues being at risk of hypertrophy and fatigue failure. It also reduced micromovement (separation) between the implant components, which is significantly related to the pumping effect and possible inflammation. Both static and fatigue analyses, used to examine short- and long-term stability, demonstrated the advantages of the hex abutment over the non-hex type for the stability of the implant components. Moreover, although its impact was not as significant as that of the abutment type, a large crown-implant ratio (CIR) increased bone strain and stress in the implant components, particularly under oblique loading.

• Smart Structures and Systems
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• 제23권2호
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• pp.107-122
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• 2019

As one of the most important parameters in structural health monitoring, structural frequency has many advantages, such as convenient to be measured, high precision, and insensitive to noise. In addition, frequency-change-ratio based method had been validated to have the ability to identify the damage occurrence and location. However, building a precise enough finite elemental model (FEM) for the test structure is still a huge challenge for this frequency-change-ratio based damage detection technique. In order to overcome this disadvantage and extend the application for frequencies in structural health monitoring area, a novel method was developed in this paper by combining the cross-model cross-mode (CMCM) model updating algorithm with the frequency-change-ratio based method. At first, assuming the physical parameters, including the element mass and stiffness, of the test structure had been known with a certain value, then an initial to-be-updated model with these assumed parameters was constructed according to the typical mass and stiffness distribution characteristic of shear buildings. After that, this to-be-updated model was updated using CMCM algorithm by combining with the measured frequencies of the actual structure when no damage was introduced. Thus, this updated model was regarded as a representation of the FEM model of actual structure, because their modal information were almost the same. Finally, based on this updated model, the frequency-change-ratio based method can be further proceed to realize the damage detection and localization. In order to verify the effectiveness of the developed method, a four-level shear building was numerically simulated and two actual shear structures, including a three-level shear model and an eight-story frame, were experimentally test in laboratory, and all the test results demonstrate that the developed method can identify the structural damage occurrence and location effectively, even only very limited modal frequencies of the test structure were provided.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.294.1-294.1
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• 2016

Transition metal dichalcogenides (TMDs) with two-dimensional layered structure, such as molybdenum disulfide (MoS2) and tungsten diselenide (WSe2), are considered attractive materials for future semiconductor devices due to its relatively superior electrical, optical, and mechanical properties. Their excellent scalability down to a monolayer based on the van der Waals layered structure without surface dangling bonds makes semiconductor devices based on TMD free from short channel effect. In comparison to the widely studied transistor based on MoS2, researchs focusing on WSe2 transistor are still limited. WSe2 is more resistant to oxidation in humid ambient condition and relatively air-stable than sulphides such as MoS2. These properties of WSe2 provide potential to fabricate high-performance filed-effect transistor if outstanding electronic characteristics can be achieved by suitable metal contacts and doping phenomenon. Here, we demonstrate the effect of two different metal contacts (titanium and platinum) in field-effect transistor based on WSe2, which regulate electronic characteristics of device by controlling the effective barreier height of the metal-semiconductor junction. Electronic properties of WSe2 transistor were systematically investigated through monitoring of threshold voltage shift, carrier concentration difference, on-current ratio, and field-effect mobility ratio with two different metal contacts. Additionally, performance of transistor based on WSe2 is further enhanced through reliable and controllable n-type doping method of WSe2 by triphenylphosphine (PPh3), which activates the doping phenomenon by thermal annealing process and adjust the doping level by controlling the doping concentration of PPh3. The doping level is controlled in the non-degenerate regime, where performance parameters of PPh3 doped WSe2 transistor can be optimized.

• 한국환경복원기술학회지
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• 제18권2호
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• pp.119-131
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• 2015

The purpose of this study was to compare the differences of the ecological attributes in the two types of urban park at Suwon and Goyang city. 'Directly linked park' is forests and rivers in the vicinity, it is capable of re-supply of the species and 'Isolated park' is forests and rivers apart, it is a difficult re-supply of the species. The result of assessment of the ecological attributes in the two types of urban park was analyzed as the percentage of 'Forest zone' was high, but the percentage of 'Area of permeable pavement' and 'Bush area' was low. 'The planting structure' was mostly 1-layer structure(47%) and 'Foreign tree species' is high by half the proportion. 'Age classes' were a 2-3age classes level, and 'Water body' could barely. Thus, ecological attributes degree was very low. In addition, results of investigation whether the difference of ecological attributes degree between the two types of urban park, also statistically analyzed that there is no difference. Therefore, when establishing the composition of the future plans of the city park, to take full account of the ecological situation in the surrounding parkland, and identify the ecological potential with the parkland. Next, it should be designed and planned of the park that fully utilizing the potential of this ecological attributes.