• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.39-49
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• 2007

In this study, the performance characteristics of solid phase microextraction (SPME) were investigated for three major odorous groups that consist of 10 individual compounds ([1] volatile organic compounds (VOC): benzene, toluene, p-xylene and styrene, [2] reduced sulfur compounds (RSC): hydrogen sulfide, methyl mercaptan, dimethylsulfide (DMS), dimethyldisulfide (DMDS), and carbon disulfide, and [3] amine: trimethylamine (TMA)). For the purpose of a comparative analysis, two types of SPME fiber ([1] polidimethylsiloxane/divinilbenzene (P/D) and [2] $Carboxen^{TM}$/polidimethylsiloxane (C/P)) were test ε d against each other for a series of standards prepared at different concentration levels (100, 200, and 500 ppb). To compare the analytical performance of each fiber, all standards were analyzed for the acquisition of calibration data sets for each compound. The results of P/D fiber generally showed that its calibration slope increased as a function of molecular weight across different VOCs; however, those of C/P fiber showed a fairly reversed trend. Besides, we confirmed that the application of SPME is limited to many sulfur compounds; only two compounds (DMS and DMDS) are sensitive enough to draw calibration results out of SPME. The calibration data for RSC show generally enhanced slop values for C/P relative to P/D fiber. However, in the case of TMA, we were not able to find a notable difference in their performance.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1302-1308
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• 2010

This study the change of the safety factor before and after the reinforcement were compared by performing the parameter research based on the limit equilibrium analysis regarding the same cross section after carrying out the safety factor before the reinforcement on the virtual section in order to observe the change of the safety factor of the slop reinforced with the slope planting reinforced earth, and the variation of the safety factor according to the increase of the length of the reinforcement materials and the change of the slope height was analyzed. As the result, the reinforcement effect was insignificant at no more than 0.6 of L/H, the reinforcement length ratio when the reinforcement length was increased, as the increase of the safety factor was slow comparing with the non-reinforced slope. At 3.0m of the slope height, reinforcement on the slope is not necessary, and at 3.0m to 5.0m of the slope height, the inclination was not influencing at no less than 0.6 of L/H. At 5.0m to 9.0m of the slope height, the safety factor was mostly secured on the slope at 0.8 of L/H and the over-reinforced slope appeared at no less than 1.0 of L/H. Also, the safety factor increased as the slope height increases and the slope gets steeper till 0.8 of L/H, but the slope steepness affects more on the increase of the safety factor than the reinforcement material, as the reinforcing force by the reinforcement material became steady.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.117-129
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• 2009

This paper studied the safety management network system of infrastructure which constructed smart sensors, closed-circuit television(CCTV) and monitoring system. This safety management of infrastructure applied to bridge, cut slop and tunnel, embankment etc. The system applied to technologies of standardization guidelines, data acquirement technologies, data analysis and judgment technologies, system integration setup technology, and IT technologies. It was constructed safety management network system of various infrastructure to improve efficient management and operation for many infrastructure. Integrated safety management network system of infrastructure consisted of the real-time structural health monitoring system of each infrastructure, integrated control center, measured data transmission using i of tet web-based, collecting data using sf ver, early alarm system which the dangerous event of infrastructure occurred. Integrated control center consisted of conference room, control room to manage and analysis the data, server room to present the measured data and to collect the raw data. Early alarm system proposed realization of warning and response within 5 minute or less through development of sensor-based progress report and propagation automation system using the media such as MMS, VMS, EMS, FMS, SMS and web services of report and propagation. Based on this, the most effective u-Infrastructure Safety Management System is expected to be stably established at a less cost, thus making people's life more comfortable. Information obtained from such systems could be useful for maintenance or structural safety evaluation of existing structures, rapid evaluation of conditions of damaged structures after an earthquake, estimation of residual life of structures, repair and retrofitting of structures, maintenance, management or rehabilitation of historical structures.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.3
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• pp.321-337
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• 1992

The objective of this study was to compare the condylar path and the anterior angle of articular fossa and to analyze the pattern of condylar path in edentulus patients. Nineteen male and female edentulous patients with normal masticatory system ranging in age 42 to 78, without present symptoms and any history of TMJ disturbance were selected for this study. On the computer analysis on the transcranial radiographs of the TMJ, the angle of slope of articular eminance and condylar path to the Frankfort Horizontal Plane and the height of glenoid fossa was measured respectively, and stuied their interrelationship comparatively. Obtained results were asfollows. 1. The angle of the slope of articular eminence averaged 37.28 degree. and there was no significant difference between the right and left side. 2. The condylar path angle averaged 29.05 degree and there was no significant difference between the right and left side. 3. The height of the glenoid fossa averaged 8.11 mm and there was no significant difference between the right and left side. 4. The sequence of the frequence of condylar movement patterns were concavex curve(39.5% ), 'S' shape curve(34.2%), reverse 'S' shape(15.8%) and convex curve(10.5%). 5. The horizontal distance of the point of the changed curve of the condylar path averaged 2.91 mm. 6. The height of glenoid fossa was highly correlated to the slope of articular eminence and relatively highly correlated to tile condylar path and the condylar path was closely correlated to the slop of articular eminence.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.291-294
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• 2015

Recently, ZnO based oxide TFTs used in the flexible and transparent display devices are widely studied. To apply to OLED display switching devices, electrical performance and stability are important issues. In this study, to improve these electrical properties, we fabricated TFTs having Al doped Zinc Oxide (AZO) layer inserted between the gate insulator and ZnO layer. The AZO and ZnO layers are deposited by Atomic layer deposition (ALD) method. I-V transfer characteristics and stability of the suggested devices are investigated under the positive gate bias condition while the channel defects are also analyzed by the photoluminescence spectrum. The TFTs with AZO layer show lower threshold voltage ($V_{th}$) and superior sub-threshold slop. In the case of $V_{th}$ shift after positive gate bias stress, the stability is also better than that of ZnO channel TFTs. This improvement is thought to be caused by the reduced defect density in AZO/ZnO stack devices, which can be confirmed by the photoluminescence spectrum analysis results where the defect related deep level emission of AZO is lower than that of ZnO layer.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.268-273
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• 1999

To measure the precision of Soiltek$^{(R)}$ KA-1 spectrophotometric measurement of soil available phosphate, standard deviation, C;V, and relative sensitivity were investigated, comparing to Lancaster method. Available phosphate concentration measured by Soiltek$^{(R)}$ KA-1 spectrophotometric method was highly correlated with Lancaster method($r=0.998^{***}$) and the slop of regression equation was close to 1.0. There were no differences in standard deviation. CV, and relative sensitivity for soil available phosphate concentrations measured by two methods. Regarding to convenience of experimental procedure and instrumental operation, and time saving analysis, Soiltek$^{(R)}$ KA-1 spectrophotometric measurement for soil available phosphate is highly recommended.

• Journal of Korea Water Resources Association
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• v.40 no.5
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• pp.373-382
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• 2007

The exact resolution of channel initiation points is not so easy because of the dynamic behaviors of water movement on the hillslope. To this end, Kim, Joocheol and Kim, Jaehan(2007) have represented the channel network in real world basins for slope-area regimes using DEM. This study is its sequential content and then proposes the reliabilities of the hypothetical channel networks identified from DEM, which are assessed based on the geometric characteristics of drainage density and source-basin. The resulting drainage structures on the natural basin can be found to be depicted remarkably depending on the hypothetical channel network applied by slop-area threshold criterion. In addition, it is shown that there is a wonderful geometric similarity between the shapes of source- basin in a geomorphologically homogeneous region. Area threshold criterion could have restricted the shape of source-basin, so that it might bring about the incorrect drainage structures. But the hypothetical channel networks identified from DEM deserves special emphasis on expressing the space-filling structures nonetheless.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.269-280
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• 2014

To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

• Composites Research
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• v.17 no.5
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• pp.39-46
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• 2004

In this study, the strength of spatially reinforced composites (SRC) are predicted by using stiffness reduction for each structural element composed of a rod stiffness in each direction and a matrix stiffness proportional to its rod volume fraction. Maximum failure strain criteria is applied to rod failure, and modified Tsai-Wu failure criteria to matrix failure. The material properties composed of the tensile failure strain of a rod, the compressive failure strain of 3D SRC, the tensile and compressive strength of the 3D SRC in the $45^{\cir}$ rotated direction from a rod and the shear strength of the 3D SRC are measured to predict the SRC strength. The strength distributions of the 3D/4D SRC in rod and off-rod direction have the largest and the smallest values, respectively. A variable load step is selected to increase an efficiency of strength distribution calculation. Uniform load step is applied when a load history is needed. The results of compressive strength from analysis and experiment show the 18 % difference though the initial slop is coincident with each other.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.105-116
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• 2006

This research introduces the method to measure cross-slope using Road Safety Survey and Analysis Vehicle(RoSSAV) with multiple sensors. Cross-slope is an important element like horizontal alignment and vertical alignment in evaluating safety of the roads. In many cases, cross-slope is different from drawings due to frequent overlays. It is extremely difficult to measure cross slope at the roads which has huge traffic volume. Therefore, the algorithm, which can be used when driving the RoSSAV with CPS/INS and Laser Scanner sensors was developed for measuring the cross-slop. Also, in order to examine the algorithm, the superelevation was measured by Laser Scanner and GPS/INS system during travelling and the result was verified by statistical verification.