• Journal of Environmental Science International
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• v.15 no.7
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• pp.635-642
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• 2006

Present study evaluated the low-temperature destruction of n-hexane and benzene using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst. The parameters tested for the evaluation of catalytic destruction efficiencies of the two volatile organic compounds(VOC) included input concentration, reaction time, reaction temperature, and surface area of catalyst. It was found that the input concentration affected the destruction efficiencies of n-hexane and benzene, but that this input-concentration effect depended upon VOC type. The destruction efficiencies increased as the reaction time increased, but they were similar between two reaction times for benzene(50 and 60 sec), thereby suggesting that high temperatures are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Similar to the effects of the input concentration on destruction efficiency of VOCs, the reaction temperature influenced the destruction efficiencies of n-hexane and benzene, but this temperature effect depended upon VOC type. As expected, the destruction efficiencies of n-hexane increased as the surface area of catalyst, but for benzene, the increase rate was not significant, thereby suggesting that similar to the effects of the re- action temperature on destruction efficiency of VOCs, high catalyst surface areas are not always proper for economical thermal destruction of VOCs. Depending upon the inlet concentrations and reaction temperatures, almost 100% of both n-hexane and benzene could be destructed, The current results also suggested that when applying the mesh type transition Metal Pt/SS catalyst for the better catalytic pyrolysis of VOC, VOC type should be considered, along with reaction temperature, surface area of catalyst, reaction time and input concentration.

• Journal of Korea Technology Innovation Society
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• v.19 no.1
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• pp.1-28
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• 2016

Current Korean innovation system is facing a new turning point while the growth-oriented and S&T provide-oriented development strategy. Accordingly, there are needs for not only system transition in various area, such as sustainable energy, agriculture, and rural area but also STI policy paradigm shift to create a new innovative pathway. Living lab is being discussed in European country as a new innovative model based on user participation and as a niche experiments for sustainable system transition. This study attempts to analyze the living lab cases which are for the purpose of energy transition, agriculture rural areas system transition, and STI policy paradigm shift. Based on this analysis, the implications were derived in Korea. European Suslab project, C@R project, and Taiwan living lab, promoted diverse transitional experiments successfully by collecting users' background and experiences from pre-planning stage and by maintaining the user-driven innovative actions within the whole development process. This result provides various suggestions to current Korean situation that central government and local governments are considering the introduction of living lab. Living lab can also be utilized as a strategic niche experiments for socio-technical system transition in region or country, as a mean of policy integration, and as a new regional innovation model. In addition, it can be an important platform to realize the policy integration reflecting the user and demand-side which are highlighted in recent innovative policy paradigm.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.510-516
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• 2002

Recently the laser welding technology has been applied increasingly for the automotive bodies. But the lap joint laser welding for 3 dimensional automotive body is new while the butt joint laser welding is well known as the tailored blank technology. In this study, the process window was found for the full penetration welding of the lap joint of the 1mm-thick high strength steel sheets. The limit curves and characteristic curves were suggested to define the boundaries and the contour lines in a space of the welding speed and the gap size. The characteristics of the weld sectional geometry were used to determine the limit curves. They are bead width, penetration depth and sectional area. After the observed data was analysed carefully, it was noticed that there was a transition point at which the sectional shape was changed and the bead area jumped as the welding speed was increased. Also a new concept of 'input energy Per volume' was suggested to distinguish the difference at the transition Point. The difference of sectional areas at the transition point can be related to the dynamic keyhole phenomena.

• Journal of the Korean housing association
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• v.25 no.6
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• pp.19-26
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• 2014

This study aims to derive street design alternative which can be applied to residential area as the functions of land use have been changed. The main findings are as follows; First, the study area in this research is on the process of the functional transition from full residential use to residential-commercial mixed use with cafes and restaurants. Second, dead-end streets in residential areas needs to be widened in order to meet the increasing needs of pedestrians and cars. One of the suggested strategies is to remove fences on the dead-end streets. Third, based on the main findings, this research can suggest following policies. Citizen participation is necessary in building land use plans and space design in old residential areas. Citizens can participate in architectural and landscape contracts, district-unit plan with the help of experts such as urban planners and architects.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.378-382
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• 1999

We evaluated the effect of joining process such as contact method, shape of joined area and pressure on the electrical property of Bi-2223 superconducting tape. It was observed that the current capacity was reduced at the transition area of the joined tape and was significantly dependent on the uniaxial pressure. The lap-joined tape, fabricated with a pressure of 1,000-1,600 MPa, show the highest value of current capacity(80-90%) of the tape itself. It is believed the highest value of current capacity results from improvement in core density, contacting area and grain alignment, etc. In addition, the irreversible strain( ${\varepsilon}$ irrev) for the joined tape· was measured to be 0.1%, smaller than that of enjoined tape( ${\varepsilon}$ irrev = 0.3%). The decrease in the strength and irreversible strain for joined tape is believed to be due to the irregular geometry/morphology of the transition area of the tape.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.3
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• pp.34-45
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• 1993

This study aims to analyze the mixing characteristics of hydrogen considered as a new fuel for internal combustion engines. As the physical property of helium gas is similar to that of hydrogen, helium gas was used in this study. To analyze the steady and unsteady behavior of jet, helium gas was injected into the stationary atmosphere at the normal temperature and pressure. Concentration of helium gas in the center of jet flow is in inverse proportion with axial distance from the nozzle tip. This agrees with the free jet theory of Schlichting. The relative equation for dimensionless concentration to radial/axial distance the axial distance of potential core region, the cone angle a of the jet flow and the relative equation for arriving distance of the front of jet flow to the lapse of time are obtained. But free jet theory of Schlichting in the dimensionless concentration is not in agreement with the present experimental results of the distance of the radial direction. It needs more study. When the arrival frequency of jet flow is used as a parameter, the transition area changing from unsteady flow area into steady flow area becomes gradually wider downstream, but its ratio for the whole unsteady flow area gradually decreases.

• Korean Journal of Environment and Ecology
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• v.16 no.3
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• pp.223-232
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• 2002

For the zoning of natural ecosystem, Vegetation Index is calculated from the vegetation data surveyed on Baekdudaegan (Pijae-Doraegijae). Five factors -biodiversity, conservation value of the stand, environmental quality, longevity of the stand, site productivity- are considered in the calculation of Vegetation Index. Vegetation Index might be a useful zoning tool for management of Baekdudaegan. For Vegetation Index I, 59 sample plots 52.2% of total 113 sample plots are belong to core area, 34 sample plots 30.l% and 20 sample plots 17.7% are belong to buffer zone and transition area, respectively. For Vegetation Index II, 49 sample plots 43.4% of total 113 sample plots are belong to core area, 38 sample plots 33.6% and 26 sample plots 23.0％ are belong to buffer zone and transition area, respectively.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.431-444
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• 2018

Numerical simulations have been conducted to study the unstart/restart characteristics of an over-under turbine-based combined-cycle propulsion system (TBCC) inlet during the inlet transition phase. A dual-solution area exists according to the Kantrowitz theory, in which the inlet states may be different even with the same input parameters. The entire transition process was divided into five stages and the unstart/restart hysteresis loop for each stage was also obtained. These loops construct a hysteresis surface which separates the operating space of the engine into three parts: in which a) inlet can maintain a started state; b) inlet keeps an unstarted state; c) inlet state depends on its initial state. During the transition, the operation of the engine follows a certain order with different backpressures and splitter angles, namely control route, which may result in disparate inlet states. Nine control routes with different backpressures and transition stages were designed to illuminate the route-dependent behavior of the inlet. The control routes operating towards the unstart boundary can make the inlet transit from a started state into an unstarted one. But operating backward the same route cannot make the inlet restart, additional effort should be made.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.2
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• pp.92-96
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• 2010

The National Health Insurance Corporation (NHIC) was performed population health checkup survey program with especially two target ages, 40 years and 66 years old that were called as "life transition period" for national collective prophylaxis of cardiovascular diseases in Korea. We were investigated and compared between two age groups with the serum levels of cholesterol and triglyceride from data of the survey in Daegu province, Korea at April, 2007. Data of one hundred persons per each age (40 years and 66 years old) were collected and investigated for risk factors for chronic degenerative diseases including serum lipid concentration, health habits of drinking, smoking, exercise etc. In spite of the definite difference of life transition of the each age, the transition from adolescence to adulthood at 40 years old, and from adulthood to senescence at 66 years old, there were no significant difference of total cholesterol and triglyceride between two age groups.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.1-11
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• 2018

Sound propagation in shallow water changes from spherical spreading to cylindrical spreading, depending on boundary conditions, and this point is defined as a transition point of the sound propagation condition. Theoretically, the transition point can be estimated using the transmission loss as a function of source-receiver range. In this paper, the transmission loss curve in a Pekeris waveguide is predicted using a parabolic-equation based acoustic propagation model and using this transmission loss curve, the range from the source of the transition point is estimated, which is compared to the critical distance calculated using the sound speed ratio of water to sediment. In addition, the effects of the sound speed profile and source depth change on the transition point are investigated. Finally, the transition point is estimated using the transmission loss data measured during the period of the SAVEX15 (Shallow Water Acoustic Variability EXperiment 2015) conducted 65 km southwest of Jeju Island in May 2015, and it is compared to the ocean environmental parameters to understand the properties of sound propagation in the experimental area.