• Journal of Biosystems Engineering
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• v.27 no.6
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• pp.565-572
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• 2002

In order to control the root-zone temperature of greenhouse crops in the hydroponics at hot and cold season, heat pump system for cooling and heating was built and tested in this work. The system was air-to-water type and vapour compression type. The heating and cooling mode was selected by the four way valve. Capacity of the compressor was 3.75㎾ and heat transfer area of the evaporator and the condenser were 3.05㎡ and 0.6㎡, respectively. According to the performance test, it could supply heat of 42,360 to 64,372kJ/h depending on the water circulation rate of 600 to 1,500ℓ/h, respectively, when indoor air temperature was 10∼20$\^{C}$. COP of heat pump system was 3.0 to 4.0 in the heating mode. But, COP of the cooling mode was 1.3 to 2.1 at indoor temperature of 20∼35$\^{C}$. The feasibility test in the greenhouse the developed heating and cooling system was installed, showed that the heating cost of the developed system was only about 13% of that of the conventional heating system. The heating cost of the developed system was 367won/day(electric consumption 9.7㎾h/day), while that of the conventional system was 2,803won/day(oil consumption 7.7ℓ/day) at the same heating mode.

• Journal of Powder Materials
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• v.8 no.3
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• pp.163-167
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• 2001

A bulk porous $CaZrO_3/MgO$ composite with plantinum nano-dispersion was synthesized in air atmosphere through the combination of several in situ reactions, including the pyrolysis of $PtO_2$. A mixture of $CaMg(CO_3)_2$(dolomite), $ZrO_2$, $PtO_2$ and LiF (0.5 wt%, as an additive) was cold isostatically pressed at 200 MPa and sintered at $1100^{\circ}C$ for 2 h. The porous $CaZrO_3/MgO/Pt$ composite ($CaZrO_3/MgO$ : Pt=99 : 1 in volume) had a uniformly open-porous structure (porosity: 56%) with three-dimensional (3-D) network and a narrow pore-size distribution, similarly to the porous $CaZrO_3/MgO$ composites reported before. Catalytic Properties (viz., NO direct decomposition and NO reduction by $C_2H_4$) of the $CaZrO_3/MgO/Pt$ composite were investigated up to $900^{\circ}C$. In the absence of oxygen, the NO conversion rate reached ~52% for the direct decomposition and ~100% for the reduction by $C_2H_4$, respectively. The results suggest the possibility of the porous composite as a multifunctional filter, i.e., simultaneous hot gas-filtering and $de-NO_x$ in one component.

• Journal of the Korean Society of Food Culture
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• v.33 no.2
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• pp.125-132
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• 2018

This study was carried out to determine the optimal storage conditions by examining the effects of the storage conditions on the quality of red pepper powder during storage in households. Red pepper powder was stored at room temperature ($20^{\circ}C$), refrigeration (2 and $-1^{\circ}C$) and frozen (-5 and $-20^{\circ}C$) for 3, 6, 9 and 12 months. The ASTA color value, capsanthin content and redness ($a^{\ast}$) of the red pepper powders stored at -5 and $-20^{\circ}C$ were not decreased significantly depending on the storage temperatures until 9 months. The pH of red pepper powder stored at $20^{\circ}C$ decreased significantly until 9 months and increased at 12 months. The microbiological quality of the red pepper powder stored at -5 and $-20^{\circ}C$ was more stable during long-term storage. In the sensory evaluation of red pepper powder stored under all conditions, the overall freshness, redness, hot flavor, moisture release, and edibility decreased with increasing storage period from the control to 12 months. Moisture release increased from 3 months to 12 months. Overall, red pepper should be stored at low temperatures (2, $-1^{\circ}C$) for up to 6 months, and frozen (${\geq} -5^{\circ}C$) for 6 to 9 months. The optimal temperature for long-term storage (${\geq}9$ months) was $-20^{\circ}C$.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.95-103
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• 1993

A conceptual thermoelectric heat pump(cooling mode) of small capacity is designed. Its performance is investigated through parametric analysis. COP and cooling capacity decease as the ambient temperature increases with ${\mu}$, J, T$\sub$wi/, fixed. To design a system of fixed capacity comes to calculate ${\mu}$ and J when T$\sub$wi/, and T$\sub$a/ are given. As v is fixed by semi-conductor manufacturers, optimum combination of n and I should be searched for ν. Optimum current could be calculated using ${\mu}$-J curve and optimum value of ${\mu}$. COR$\sub$R/ increases as water flow rate increases and T$\sub$a/ decreases. The effect of heat transfer coefficient at hot(heat releasing) side is more significant than that at cold(heat absorbing) side.

• Journal of the Korean Society of Food Culture
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• v.19 no.5
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• pp.573-586
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• 2004

This study aims at providing useful information to establish subdivided marketing direction by deriving factors of significant extent and practicable extent of buffet users toward menu quality among super deluxe hotels in Gyeongju, and furthermore aims at presenting implications for efficient management result and sales increase of buffet in the future. The result of positive analysis is as follows. Firstly, in result of analyzing difference between importance and performance of hotel buffet in Gyungju area, importance is much higher than performance. Secondly, respondents consider that the most important menu of hotel buffet is main dish such as hot food and instant food rather than menu such as beverage, soup and salad. When it comes to attribute of menu quality, it appeared that respondents put highly significant extent on sanitariness of food, freshness of food, flavor of food, and seasonality and variety of menu. Thirdly, oriental instant food is included in the second quadrant of IPA regarding buffet menu which should be intensively managed. And three attributes such as temperature of food, time of changing food, and creativity of menu are included in the second quadrant of IPA graph by attribute of hotel buffet's menu quality. Lastly, in IPA graph by hotel, the following menus of each hotel need to be intensively managed: Oriental instant food of A hotel, Western cold food of B hotel, Oriental instant food, Western instant food, and Oriental dessert of C hotel, and Western porridge soup, Oriental instant food, and Western instant food of E hotel. The aforementioned menus should be improved.

• The Journal of the Korean Society for Microbiology
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• v.3 no.1
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• pp.5-14
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• 1968

Prostitutes living in Songdo beach in Pusan, for two years period (from September 4, 1964 to August 28, 1966) were investigated for the present status and Venereal Diseases. The following results were obtained. 1. Age distribution:The youngest was 18 years old and the oldest 29. The group between 22-25 years old was 72.8%, approximately three fourth of all prostitute. 2. Educational background: From illiterate to college graduated. The group of graduated primary school was 80.7%, approximately four fifth of all prostitutes. 3. Distribution of birth places: From all cities and provinces in Korea except Chejudo Island province. Kyongsang Namdo province was highest(24%), Kyongsan Pukdo province 18%, Pusan city 12%, and Seoul city 11%. 4. Monthly and weekly Venereal Diseases examination to prostitutes: Total examined cases were 7757, consisting of 323 monthly, and 75 weekly. Total numbers of disqualified persons were 592(7.63% of total examined), consisting of 25 monthly, and 6 weekly. 5. Clinical and laboratory findings of the rejected prostitutes at the Venereal Disease examination: Among total cases of rejected 592, gonococcal positive cases were 2.89%, staining by gram's method, cervical erosions 3.53%, and numerous pus cells but gonococcal negative 1.53%. 6. Seasonal distribution of prostitutes : Songdo beach is one of the famous sea shore sightseeing resort in Pusan. Therefore, numbers of prostitutes were increasing in hot season, summer and decreasing in cold season, winter. 7. Number of disqualified prostitutes at the Venereal Disease examination by seasonal trend: In autumn 18.04%, winter 8.68%, spring 5.85%, and summer 4.43%, in order as described, the decreasing tendency was observed. 8. Serolgical tests for syphilis: VDRL slide method and Kolmer-Wassermann reaction were performed to the prostitutes. STS were positive by VDRL slide method in 8.33-33.87%, Kolmer-Wassermann reaction in 8.33-27.42% of the prostitutes. The results of sero-positive of syphilis showed tendency toward gradually increase from 1964 to 1966. 9. Authors were observed only 1 case or soft chancer, but neither lymphogranuloma venereum nor granuloma inguinale were detected.

• Journal of the Korean housing association
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• v.20 no.2
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• pp.77-86
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• 2009

The purpose of this study was to examine the household characteristics, the actual residential environment of the elderly living with their offsprings together in Gwangju. We also evaluated their satisfaction with the needs for remodeling of their houses and the different opinions about those things between the elderly and their off springs. We used comparative and descriptive T-test in statistical analysis. The results were as follows. There were more families living in the detached houses than those living in the apartments. The average size of the houses was 100.8 square meters. The mean residence period was 13.5 years. The sons were usually the legal householders. The residents who experienced remodeling before reassigned the furniture and installed the bathtub, which was designed to be sat on comfortably in a common. A few residents installed safety system such as alarms for incident fire or gas, convenient knobs for handling and faucets for running hot or cold water separately. After the installation of alarms, convenient knobs of windows or door, Customer satisfaction for those things were quite high. But that for the installation of safety bar were the lowest in contrast. The most things the old wanted to change were to rearrange bedrooms and bathrooms on the first floor and to decorate them in westernized styles. They didn't need to set up safety bars or shower instrument for modulating heights. The second generation wanted to install the blinds or curtains more than the third generations.

• Journal of ILASS-Korea
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• v.25 no.1
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• pp.27-33
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• 2020

NOx, PN and CO emissions from diesel trucks make up a significant portion of domestic air pollutant emissions. Therefore, test vehicles with various emission standards and driving modes were selected to evaluate the emission characteristics of regulated pollutants (NOx, PN, CO) in medium-duty trucks. As a result of test, all test vehicles were satisfied with Euro 5 or 6 regulation. NOx emissions of Euro 6 vehicles with after-treatment of LNT + DPF were lower than those of Euro 5 vehicles with DPF. In WLTC mode, all vehicles have high NOx emissions at section of extra high speeds, which are determined by increased fuel consumption and high combustion temperatures. CO and PN emissions from all vehicles were found to be low at section of low speeds. Also, The NO₂/NOx ratio was analyzed at 7-23% in each mode, and the NO₂/NOx ratio increased as the average vehicle speed increased. In NIER 9 mode, the CO, HC, and PN emissions were higher under cold conditions of engine than hot conditions of engine. In addition, vehicles with after-treatment system of LNT have similar NOx emissions level in this study.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.26-34
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• 2011

The present work addresses structural characteristics of natural gas flames in a lean premixed swirl-stabilized combustor with an attention focused on the effect of the formation of recirculation zones on the combustion instability. It is known that the recirculation zone plays an important role in stabilizing a turbulent, premixed natural gas flames by providing a source of heat or radicals to the incoming premixed fuel and air. To improve our understanding of the role of recirculation zones, the flame structure was investigated for various mixture velocities, equivalence ratios and swirl numbers. The optically accessible combustor allowed for the application of laser diagnostics, and Particle Image Velocimetry(PIV) measurements was used to characterize the flame structure under both cold flow conditions and hot flow conditions. Dynamic pressures were also measured to investigate characteristics of combustion at the same time. The results indicates that the formation of recirculation zone is strongly related to the occurrence of thermo-acoustic instabilities.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.111-119
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• 2007

The annual mean temperature of South Korea has risen by $1.3^{\circ}C$ for last 100 years by urbanization and industrialization. Especially, the frequency of unusual hot weather in summer increases for a long time and the frequency of unusual cold weather in winter clearly decreases. In recently, The considerable portion of curtain wall system is appled to building skin in domestic. As related to this, the Korea Institute of Construction Technology devised the box typed double skin facade(It is occasionally called as FDFS : Functional Double Facade System) as an alternative that reflects the distinctive local climate and saves cooling energy. Two mock-ups($49m^*4.9m$) applied to single skin(curtain wall) and double skin each were monitored under the outdoor condition. Therefore, the characteristics of natural ventilation and cooling energy consumption of each window had been analyzed in real time. The results of this study are summarized as follow, Analysis of the experiment on an air conditioner: the indoor temperature of the chamber with FDFS is lower than that of the chamber with single skin facades by $3{\sim}6$ degrees(C). A temperature variation of about $1{\sim}2$ degrees between the 0.2m and 1.7m height of the mock-up occurs in FDFS, while that of about maximum 7 degrees occurs in single skin facade at noon with abundant intensity of solar accident. Also, 67 percent of energy consumption for air conditioning has been saved.