• Applied Biological Chemistry
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• v.45 no.2
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• pp.101-107
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• 2002

The essential oils isolated from leaves, flowers, stems, and fruits of Vitex rotundifolia by steam distillation and extraction (SDE) method were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 76 components detected by GC, 42 components were identified positively by GC-MS and GC co-injection with authentic standards, and 34 components were identified tentatively by mass spectral data only. They included 16 monoterpene hydrocarbons, 30 oxygenated hydrocarbons, 10 sesquiterpene hydrocarbons, 8 oxygenated sesquiterpenes, 3 diterpenes, and 9 miscellaneous components. The major components in the oil from the leaves were ${\alpha}-pinene$ (30.25%), 1,8-cineole (19.89%), sabinene (9.56%), ${\alpha}-terpineol$ (7.94%), ${\beta}-pinene$ (5.69%), and terpinen-4-ol (2.37%), and those in the flower oil were ${\alpha}-pinene$ (25.47%), 1,8-cineole (7.69%), manoyl oxide (6.21%), ${\beta}-pinene$ (4.20%), ${\alpha}-te.pineol$ (3.76%), and sabinene (2.78%). The major components in the oil from the stems were ${\alpha}-pinene$ (13.24%), ${\alpha}-terpineol$ (10.64%), 1,8-cineole (4.40%), manoyl oxide (4.02%), ${\beta}-pinene$ (2.39%), and terpinen-4-ol (2.21%) while those in the oil from the fruits were ${\alpha}-pinene$ (20.24%), 1,8-cineole (11.47%), ${\beta}P-pinene$ (9.79%), ${\alpha}-terpineol$ (7.08%), sabinene (3.68%), and limonene (2.77%). The percentage composition of monoterpenes in the oils from the leaves and the fruits were higher than in those from the flowers and the stems, whereas the oil from the flowers and the stems were characterized by a large content of sesquiterpenes, diterpenes and other unknown high molecular weight components.

• Journal of the Korean Geosynthetics Society
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• v.18 no.3
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• pp.33-44
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• 2019

Clinker layer is a stratum structure distributed in volcanic area such as Jeju Island. The clinker layers were formed in between the repetitive action of eruption and solidification of lava flows. Since the clinker layer contains a large amount of voids accompanied by the lava gas ejection process, there is a possibility of inducing overall stability of the ground due to the low stiffness and strength of the clinker layer. Therefore, in this study, site investigation was carried out at both ends of the 00 bridge where the clinker layers exist. And, based on the ground survey results, the behavior of shallow foundations was analyzed numerically. In addition, the improved shallow foundation behavior in grouting substitution using the chemical injection method of the clinker layer was compared with the shallow foundation behavior in the ground, and the grouting substitution efficiency of each layer was analyzed. As a result, the bearing capacity, the replacement efficiency and elastic settlement were different according to the presence or absence of the sediment layer. This is because the sediment layer has a lower stiffness and density than the clinker layer.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.2
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• pp.41-48
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• 2017

A vertical multi-stage ammonia stripping reactor using E-PFR, which has been proved to be superior in anaerobic and aerobic treatment, was developed and a lab scale experiment was conducted. According to the change of stage number condition, the removal rate of the ammonia nitrogen in the reactor with 0-stage was about 52.5% after 8 hours (pH 10, temperature $35^{\circ}C$, and the air/liquid ratio $3min^{-1}$) However, in the reactor with 5-stage, the removal efficiency was about 62.6%. According to the change of pH condition, the removal rate of ammonia nitrogen was about 42.6% at pH 9 after 8 hours, and was about 74.4% at pH 11 (5-stage reactor, temperature $35^{\circ}C$, and the air/liquid ratio $3min^{-1}$). According to the change of temperature condition, the removal rate of the ammonia nitrogen was about 51% at $25^{\circ}C$ after 8 hours (5-stage reactor, pH 10, and the air/liquid ratio $3min^{-1}$), and was about 87.2% at $45^{\circ}C$. According to the change of air injection volume condition, the removal rate of the ammonia nitrogen was about 45.8% at $2min^{-1}$ after 8 hours (5-stage reactor, pH 10, and at $35^{\circ}C$). and was about 75% at $4min^{-1}$. Based on these results, we will follow up the applicability of the actual plant in the future through continuous operation evaluation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.7
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• pp.492-507
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• 2010

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2009. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery and piping, and new and renewable energy. Various topics were covered in the field of general thermal and fluid flow such as an expander, a capillary tube, the flow of micro-channel water blocks, the friction and anti-wear characteristics of nano oils with mixtures of refrigerant oils, etc. Research issues mainly focused on the design of micro-pumps and fans, the heat resistance reliability of axial smoke exhaust fans, and hood systems in the field of fluid machinery and piping. Studies on ground water sources were executed concerning two well type geothermal heat pumps and multi-heat pumps in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included the heat transfer in thermoelectric cooling systems, refrigerants, evaporators, dryers, desiccant rotors. In the area of industrial heat exchangers, researches on high temperature ceramic heat exchangers, plate heat exchangers, frosting on fins of heat exchangers were performed. (3) In the field of refrigeration, papers were presented on alternative refrigerants, system improvements, and the utilization of various energy sources. Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and $CO_2$ were studied. Efforts to improve the performance of refrigeration systems were made applying various ideas of suction line heat exchangers, subcooling bypass lines and gas injection systems. Studies on heat pump systems using unutilized energy sources such as river water, underground water, and waste heat were also reported. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. In the area of cogeneration systems, papers on energy and economic analysis, LCC analysis and cost estimating were reported. Studies on ventilation and heat recovery systems introduced the effect on fire and smoke control, and energy reduction. Papers on district cooling and heating systems dealt with design capacity evaluation, application plan and field application. Also, the maintenance and management of building service equipments were presented for HVAC systems. (5) In the field of architectural environment, various studies were carried to improve indoor air quality and to analyze the heat load characteristics of buildings by energy simulation. These studies helped to understand the physics related to building load characteristics and to improve the quality of architectural environment where human beings reside in.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.