• Journal of Energy Engineering
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• v.23 no.2
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• pp.207-216
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• 2014

The energy loss can be divided into the loss caused by heat transfer and the loss caused by air flow. Heat transfer is the loss resulting from the heat transmittance of external wall, roof, and floor, and represents one of the most vulnerable elements of existing buildings. To prevent such loss, it is necessary to increase the mean heat transmittance of entire external wall, including the window, to a level above the standard regional value and ensure the air-tightness of window. The old buildings have the structure which is prone to the loss of greater air flow due to the air infiltration through the exit/entrance door upward along the stairway by the stack effect and simultaneous suction of air from each floor, and becomes even vulnerable to the loss of heat insulation for each floor, although the external wall and windows are the most vulnerable parts. The improvement plans for each floor need to be submitted in tandem with the diagnosis of whole building, regarding the diagnosis plan and energy improvement measures based on the survey of site, rather than adhering to the misconception that the replacement of window alone will result in energy-savings.

• Conservation Science in Museum
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• v.3
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• pp.71-78
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• 2001

The airtightness of museum cases in museums was measured by using CO₂ tracing gas, but it has been pointed that it has a problem with measuring the airtightness of a museum case which has a hole inside before it is used or while is being used. So studies tried to come up with alternatives which make it possible to measure the airtightness of a museum case before it is used or while it is being used if necessary by indirectly measuring the airtightness of the museum case without changing its form. Indirect measuring is done by measuring the change of Art-sorb weight and the change of temperature and humidity inside the museum case. Experiments were made for 12 days with three builtin wall case installed at the same place without turning on the lights but with Art-sorb and the data logger of temperature and humidity put into museum case. The change rate was produced with the change of temperature and humidity inside the museum case divided by that of those around museum case. As a result, the temperature change rate of museum case A(0.67) was lower than that of museum case B(0.69) or museum case C(0.79). The humidity change rate of museum case A(0.12) was lower than that of museum case B(0.19) or museum case C(0.72) showing that its airtightness was the best. Also in the direct airtightness measurement by CO₂ tracing gas, the air exchange rate was compared with the humidity change rate by Art-sorb in the indirect measurement.

• Resources Recycling
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• v.25 no.6
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• pp.41-49
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• 2016

The present study was intended to prepare cobalt oxide ($Co_3O_4$) powder of average particle size 50 nm or less by spray pyrolysis reaction using the raw cobalt chloride ($CoCl_2$) solution, in order to identify the change in the nature of the particles according to the change in the nozzle tip size. When the nozzle tip was 1 mm, it turned out that most of the droplets were spherical and the surface showed very tight structure. The average particle size of the finally formed particles was 20-30 nm. When the nozzle tip size was 2 mm, some of the droplets formed were spherical, but a considerable part of them showed severely disrupted form. particles formed showed an average particle size of 30 - 40 nm. For the nozzle tip size of 5 mm, spherical droplets were almost non-existent and most were in badly fragmented state. The tightness of surface structure of the droplets has greatly been reduced compared with other nozzle tip sizes. Average size of the formed particles was about 25 nm. As the nozzle tip size increased from 1 mm to 2 mm and 3 mm, the intensities of the XRD peaks have changed little, but significantly been reduced when the nozzle tip size increased to 5mm. As the nozzle tip size increased from 1 mm to 2 mm, the specific surface area of the particles decreased, but the nozzle tip size increased to 5mm, the specific surface area remarkably increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.409-414
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• 2021

Tightness performance that blocks compartments is important for surface ships to achieve superior mission performance and survivability in combat environments. To meet the above requirements, airtightness of the structural elements and the appropriate strength to specific areas are checked during a test run after ship construction. In particular, air tests of compartments adjacent to the water surface are performed. In an air test, air is injected into the compartment up to the test pressure of the test memo. The pressure drop value is checked after 10 minutes to determine if the requirements of the corresponding area are satisfied. In summer, however, when the influence of the outside temperature is large, a phenomenon in which the internal pressure increases during the air test was identified. This phenomenon reduces the reliability of the test result. Therefore, a system was designed to compensate for temperature changes in the compartments through this study. The developed system calculates the amount of pressure change caused by a temperature change in the compartment and outputs a correction value. The pressure change was calculated using the ideal gas equation, reflecting the maintenance, increase, and decrease in temperature during the test process. A comparison of the calculated pressure correction value with the database of NIST REFPROP revealed a difference of 0.126% to a maximum of 0.253%.

• Journal of Naturopathy
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• v.9 no.2
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• pp.62-70
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• 2020

Purpose: According to the Body-EU education program, this study investigates changes after conducting education with ten subjects with autism symptoms (disability level 2~3) 63 times (126 hours) for nearly two years. Methods: Body-EU habit practice, note writings discussion, singing, Bible study, question and communication, class arrangement, etc., a total of 63 times were educated for 2 hours each week. Results: Subjects felt comfortable breathing and improved energy. Other subject's habit of an out-toed gait step and bending back alleviated. One subject made it easier to speak, so if talking with no strength. When breathing, the stuffy nose improved, the eyes became calm, and the hands and feet were warm. Subject felt like my head was cleaned. Heart tightness disappeared. Subject felt at ease as gaining confidence. The subject gained confidence in seeing whoever the other person was. The subject's pronunciation became more sophisticated, with more confidence, and his mouth cramping alleviated. Subjects with right eye movements showed a relatively high concentration in education time. Conclusions: Subjects are educated and trained in making general habits of their body from morning to going to bed. This study was a research program for ordinary people, but it confirmed with autism. Whether it was genetic autism or acquired autism, they could be somewhat relieved.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.4
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• pp.130-137
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• 2022

Due to the coronavirus disease 2019 (COVID-19) pandemic, appropriate management of sequelae and treatment of infectious symptoms became increasingly important healthcare issues. Although the practice guidelines and treatment cases based on the East Asian traditional medicine have been reported, there are rare studies on the use of Korean medicine in Korea. Therefore, this study aimed to present the progress of non-contact Korean medical treatment for infected patients at a local public health center using retrospective chart review. A total of 18 patients were prescribed with 5 days of herbal decoction and medicine extract covered by the national health insurance. With the questionnaire form, the progression and improvement of symptoms before and after treatment were evaluated using the numerical rating scale (NRS), and the treatment satisfaction and opinions were obtained. The symptoms such as cough (5.56±2.23 to 2.89±2.14), sputum (6.11±1,75 to 3.28±2.47), sore throat (6.06±2.70 to 1.47±1.62), anorexia (5.56±2.63 to 1.94±2.21), nausea (3.75±1.71 to 1.17±1.11), diarrhea (3.40±2.63 to 1.50±1.51), chest tightness (4.93±2.46 to 2.29±2.30) and fatigue (6.44±1.79 to 2.67±1.88) all improved according to the NRS, and the satisfaction with herbal medicine treatment on a 5-point Likert scale was 4.24±0.90. No side effects and adverse reactions were reported. Thereupon non-contact Korean medical treatment can be concluded that it effectively reduces the COVID-19 infection mild symptoms in restrictive extent. Since the retrospective data does not include a control group, the more confirmative data is needed by multicenter and large-scale controlled clinical study afterwards.

• Composites Research
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• v.36 no.2
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• pp.132-139
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• 2023

A linerless composite propellant tank was designed and manufactured by using the carbon fiber-reinforced composite materials which have superior strength-to-weight ratio in order to reduce weight of the tank. In this research, we designed a sub-scale composite propellant tank with a diameter of 800 mm to withstand an MEOP of 1.7 MPa. We manufactured the boss of the tank by using the same composite materials to reduce the thermal expansion difference between the boss and the secondary-bonded composite layers of the barrel in the cryogenic environment. We used the collapsible mandrel to manufacture the tank without any liner. The mandrel was made from epoxy-based composite tooling prepregs to reduce weight of the mandrel. We manufactured the test tanks by laying up the carbon fiber fabric prepregs manually on the mandrel and then applying the autoclave cure process. We performed a proof test, a helium tightness test, a repeated pressurization test, and a burst test in room temperature. The test results demonstrate that the proposed design and manufacture process satisfies all strength requirements as well as an anti-leakage requirement.

• Analytical Science and Technology
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• v.22 no.3
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• pp.191-200
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• 2009

The aim of this study was to evaluate and establish of emission test method for liquid phase building materials such as paint, adhesive, sealant by emission cell. A small-scale emission chamber and emission cell were used to evaluate emission of TVOC from paint, adhesive, sealant. The quantity of TVOC emission were measured by a gas chromatography/mass spectrometry (GC/MS). Background concentration of TVOC was below $10{\mu}g/m^3$ in the emission chamber and cell. Air tightness and recovery in chamber and cell showed good results. The recovery of thermal desorber for toluene and n-dodecane were about 120%. The repeatability of response factor and retention time in GC/MS below 30%. The method detection limit of VOCs ranged 0.04~8.82 ng. The concentration of TVOC emission using emission cell was 1.35~1.41 times higher than emission chamber. The correlation of TVOC emission using chamber and cell method was significantly high (r=0.91~0.97).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.327-340
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• 2017

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. 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 have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth 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, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving 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 analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.203-209
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• 1993

Dipyridamole is an agent that may be used to noninvasively evaluate coronary artery disease. The effect of dipyridamole infusion its generally related to its induced peripheral vasodilatory effect. In normal person, heart rate is generally increased slightly while blood pressure decrease, but the achieved double product and related myocardial oxygen consumption have no significant change. The purpose of this study is to examine the effect and side effect of dipyridamle, and to compare different response to dipyridamole among the patients. We evaluated 847 patients who underwent dipyridamole stress myocardial SPECT. 93.6% of them had induced hypotension, 0.9% showed no change of blood pressure, 5.5% had increased blood pressure. 8.3% had no change of pulse rate more than 10% of basal pulse rate. Among diabetes, 16.9% was not change of pulse rate, 6.7% in non-diabetes. There was no significant correlation between age and rate pressure product rest(RPPr), in patiens without perfusion defects on SPECT(y=7.1x+ 48.4 r=0.13 p>0.01). As increasing age, RPPs/RPPr was declined(y= -11.6x+68.9 r=0.17 p<0.01), similar results were obtained in patients with perfusion defect. The size of perfusion defect on myocardial SPECT have no correlation between RPPr and RPPs/RPPr. The side effects of dipyridamole included chest pain and chest tightness, headache, abdominal pain, dizzness, nausea, and dyspnea. As increasing age, dipyridamole-induced cardiac work at rest was increased, cardiac response to dipyridamole was decreased.