• Journal of architectural history
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• v.29 no.2
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• pp.19-30
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• 2020

In the early of Joseon Dynasty, Royal Tomb developed from stone chamber tomb to lime chamber tomb through precedents. The lime chamber tomb consists of main-chamber(JeongGwang) and sub-chamber(ToeGwang). This separation makes character to construct tumulus of the Royal Tomb half and half. By this character, the Royal Tomb are not constructed by separate structure but constructed by coadjustment. The underground structure and tumulus of the Royal Tomb affect each other in the size and method of construction. The selecting type of Royal Tomb is generally made decision through terrain and politics. This study prove the architectural structure is also one of the major cause the that select type of Royal Tomb.

• International Journal of High-Rise Buildings
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• v.3 no.2
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• pp.147-154
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• 2014

The purposes of this study were to analyze criteria for measurement chamber design dedicated curtain wall, and how to measure of performance configuration and status of the chamber that is currently being used. Main dealing criteria is AAMA 1503-09. Measurement of data is made in curtain wall Mock-up experiment station with thermal imaging camera. Measurement data using thermal imaging cameras at Mock-up curtain was made at the test site. The results of this study were as follows; There is no U-value test method for actual size of curtain wall. The thermal test outdoor chamber showed heat loss in the connection part of indoor and outdoor chamber. And the indoor chamber showed unstable temperature distribution by height.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.24-31
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• 1999

The MPI engine becomes increasingly popular because it meets two requirements of stringent pollutant emission and the lower fuel consumption. Even though supplies the same amount of fuel to each cylinder , it is hard to precisely control the air-duel ration due to the different amount of air flowing into each cylinder. The uniformity of air-fuel ration in each cylinder is considerably affected by the plenum chamber configuration . This study is focused on experimentally analyzing the flow characteristics within the plenum chamber In the present experiment , steady and valve dynamic state flow tests are performed and the flow field inside the plenum chamber is visualized and measured by utilizing a laser sheet visualization technique and a PTV method. These measured results indicate that the flow structure in the plenum chamber is highly influenced by the plenum chamber configurations, suction flow rates, crank speeds and so on.

• Transactions of Materials Processing
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• v.28 no.6
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• pp.347-353
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• 2019

The porthole extrusion process is a classic metal forming process to produce complex cross-section shaped aluminum profile. It is very difficult to design porthole die and extrusion process because of the complex shape of extrusion die and internal metal flow. The main variables in this process are ram speed, initial billet and tool temperature, and die shape. In general, the metal flow of porthole extrusion process can be divided into two steps. During the first step, the billet is divided into several parts in the porthole die bridge. During the second step, the divided billets are welded in the welding chamber. In the welding chamber, the level of welding pressure is very important for the quality of the final product. The purpose of this study is to increase the welding pressure in the welding chamber by using a two stage welding chamber. The porthole extrusion die was designed by using the Taguchi method with orthogonal array. The effectiveness of the optimized porthole die was verified by using the finite element analysis.

• KIEAE Journal
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• v.7 no.5
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• pp.53-58
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• 2007

In order to predict the indoor air pollutant, the VOCs emission rate is used through small chamber in the design process. However, the small chamber method has limitations as the convective mass transfer coefficient, the most important factor when predicting VOCs contamination of indoor air, is different between the small chamber result and the measured data in the actual building. Furthermore, the existing studies which analyzed mass transfer coefficient in the small chamber were directed on the small chambers developed at the time and FLEC(Field and Laboratory Emission Cell), thus, are different from the current small chamber which has been changed with improvements. The purpose of this study is to determine the emission rate of pollutant in multi-layered building materials, and predict the indoor pollutant concentration through the CFD(Computational of Fluid Dynamics) and CRIAQ2 based on the mass transfer coefficient on singled-layered building material by using the current small chamber widely used in Korea. Futhermore, this study used the new convective mass transfer coefficient(hm') which indicates the existing convective mass transfer coefficient(hm) including VOC partition coefficient(k). Also, formaldehyde was selected as target pollutant.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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• pp.51-58
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• 2010

Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. In this study measured stem effect correction factor for length of ionization chamber from medical linear accelerator recommend to with the use of stem correction method. For a model of the Farmer-type chamber, were used to calculate the beam quality correction factor. These interactions contribute to the apparent measured exposure. Additionally, it needs to consider ionization chamber use of small volume and stem effect of cable by a large field. Linear accelerator generated photons energy and increased dose repeatedly measured by using stem correction method. Stem effect was dependence of the energy and increases with photon energy conditions improved of beam quality. In conclusion, stem effect correction factor was measured within 0.4% calculated according to the exposures stem length and also supposed to determined below 1% of another stem correction method.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.162-172
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• 1997

We investigated passby noise measurement method in a small-sized semi-anechoic chamber satisfying the American based SAE J1470 Recommended Practice to facilitate the measurements. We have tired two passby noise prediction methods. One is line array microphone method in which the free space sound field is decomposed into its eigenfunctions in the spherical coordinates and rearranged according to the order of the spherical Hankel function. However, due to the characteristics of the spherical Hankel function, it is impossible to distinguish the function's characteristics according to the order in farfield. Consequently it can be applied in the transient region of the nearfield and the farfield. The other method is nearfield acoustic holography(NAH). Although measuring hologram for the several operational engine speeds by conventional scanning method is time-consuming work, we can greatly reduce the measuring time by selecting the appropriate engine speed through preexperimental knowledge. To verify this method we experimented with the outdoor passby noise measurements and the passby noise prediction in the small-sized semi-anechoic chamber for the identical passenger vehicle and obtained reasonable and acceptable results.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.228-236
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• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from rice fields. This method has the advantages of being simple, easily available and economical. However, a measurement result using the chamber method is an estimated value and is complete when the uncertainty is estimated. The methane emissions from a rice paddy account for the largest portion of the greenhouse gas emissions in the agriculture sectors. Although assessment of uncertainty components affecting methane emission from a rice paddy is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. The goal of this study was to elucidate influencing factors on measurement uncertainty of methane concentrations measured by a closed automated chamber system from a rice paddy. METHODS AND RESULTS: The methane sampling system is located in the rice paddy in Gyeonggi-do Agricultural Research and Extension Services (37°13'15"N, 127°02'22"E). The primary measurement uncertainty components influencing methane concentrations (influencing factors) investigated in this research were repeatability, reproducibility and calibration in the aspects of methane sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor were quantified and compared. CONCLUSION: Results of this study showed what influencing factors were more important in determination of methane concentrations measured using the chamber system and analytical instrumentation located in the monitoring site. Quantifying the measurement uncertainty of the methane concentrations in this study would contribute to improving measurement quality of methane fluxes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.252-256
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• 2001

Scattering of surface materials has been known as one of the most important aspects in evaluating the acoustics of concert halls are designed. One of the methods that can reduce the errors in estimating the reverberation time and other acoustic parameters through computer modeling is to calculate scattering coefficient of surface materials. However. so far, no objective and reliable methods measuring scattering coefficient has been suggested. In this situation, ISO has suggested the method of measuring the random-incidence scattering coefficient on surfaces in diffuse field, whereas AES has introduced a method on directional-incidence in free field. In this study, the scattering coefficients of five kinds of hemispheres (1.5, 2.0. 2.5. 3.0. 3.5cm) were measured by using the ISO method in 1：10 reverberation chamber. It was found that 3.0cm hemisphere has the highest scattering coefficient satisfying 95％ reliability.

• Journal of Climate Change Research
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• v.7 no.4
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• pp.427-432
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• 2016

Nitrous oxide is one of the main sources of greenhouse gases and its concentration has increased from 273 ppb in 1,750 to 315 ppb in 2005. Specially, nitrogen fertilizer used in agricultural soils is considered as an important source of atmospheric $N_2O$ emission. This study was conducted to estimate the difference of nitrous oxide emission as chamber position on furrow and ridge and crop existence in gas sampling chamber on upland. Four treatments used in this experiment were (1) no-fertilizer without crop in chamber on ridge, (2) fertilizer application without crop in chamber on ridge, (3) fertilizer application with crop in chamber on ridge, (4) fertilizer application without crop in chamber on ridge and furrow. Nitrous oxide emission at fertilizer application with crop in chamber on ridge were the highest while were the lowest at no-fertilizer without crop in chamber on ridge. There was no significant difference of nitrous oxide emission by chamber position, but total emission by crop existence in chamber was significant difference. Therefore, in order to estimate greenhouse gases emission using chamber method in upland, it should be considered in correlation with crop existence in chamber and characteristic changes like as the soil moisture, microbial flora by crop growth stage.