• Membrane and Water Treatment
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• v.13 no.5
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• pp.235-243
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• 2022

The paper presents the effect of operating temperatures and flow rates on the distillate flux that can be obtained from a hydrophobic membrane having the characteristics: pore size of 0.15 ㎛; thickness of 130 ㎛; and 85% porosity. That membrane in the present investigation could be the direct contact (DCMD) or the air-gap membrane distillation (AGMD). To model numerically the membrane distillation processes, the two-dimensional computational fluid dynamic (CFD) is used for the DCMD and AGMD cases here. In this work, DCMD and AGMD models have been validated with the experimental data using different flows (Parallel and Counter-current flows) in non-steady-state situations. A good agreement is obtained between the present results and those of the experimental data in the literature. The new approach in the present numerical modeling has allowed examining effects of the nature of materials (Polyvinylidene fluoride (PVDF) polymers, copolymers, and blends) used on thermal properties. Moreover, the effect of the area surface of the membrane (0.021 to 3.15 ㎡) is investigated to explore both the laminar and the turbulent flow regimes. The obtained results found that copolymer P(VDF-TrFE) (80/20) is more effective than the other materials of membrane distillation (MD). The mass flux and thermal efficiency reach 193.5 (g/㎡s), and 83.29 % using turbulent flow and an effective area of 3.1 ㎡, respectively. The increase of feed inlet temperatures and its flow rate, with the reduction of cold temperatures and its flow rate are very effective for increasing distillate water flow in MD applications.

• Korean Journal of Clinical Pharmacy
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• v.32 no.2
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• pp.84-92
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• 2022

Background: Topical corticosteroids (TCs) are available both as over-the-counter drugs and prescription medicines at pharmacies. Although they are generally safe drugs, inappropriate and excessive use could result in potential side effects. Thus, it is important to have appropriate knowledge regarding the use of TCs. We performed a cross-sectional survey to assess public knowledge and the potential misuse or overuse of TCs. Methods: A cross-sectional and nationwide online survey was conducted among participants who were aware of TCs. The survey items included sources of information, indications, potential side effects, and methods of application of TCs. A comparative analysis was conducted between those with (TC users) and without (TC non-users) an experience of using TCs. Results: Among 3,000 participants, 74.4% were TC users. The mass media was the most common information source of TCs, and only one-third of the surveyed people relied on pharmacists or doctors for information. Regarding indications and application methods, incorrect answer rate was high in some items, but respondents showed adequate knowledge. However, awareness of the safety of TCs was low. Overall, the TC users showed a higher knowledge of TCs than TC non-users. Conclusions: Public knowledge of the use of TCs appears to be appropriate. However, we found potential misuse or overuse of some items and a lack of awareness of the side effects concerning TCs. Thus, healthcare professionals' significant role is required.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.290-294
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• 2023

Among various types of harmful gases, hydrogen sulfide is a strong toxic gas that is mainly generated during spillage and wastewater treatment at industrial sites. Hydrogen sulfide can irritate the conjunctiva even at low concentrations of less than 10 ppm, cause coughing, paralysis of smell and respiratory failure at a concentration of 100 ppm, and coma and permanent brain loss at concentrations above 1000 ppm. Therefore, rapid detection of hydrogen sulfide among harmful gases is extremely important for our safety, health, and comfortable living environment. Most hydrogen sulfide gas sensors that have been reported are electrical resistive metal oxide-based semiconductor gas sensors that are easy to manufacture and mass-produce and have the advantage of high sensitivity; however, they have low gas selectivity. In contrast, the electrochemical sensor measures the concentration of hydrogen sulfide using an electrochemical reaction between hydrogen sulfide, an electrode, and an electrolyte. Electrochemical sensors have various advantages, including sensitivity, selectivity, fast response time, and the ability to measure room temperature. However, most electrochemical hydrogen sulfide gas sensors depend on imports. Although domestic technologies and products exist, more research is required on their long-term stability and reliability. Therefore, this study includes the processes from electrode material synthesis to sensor fabrication and characteristic evaluation, and introduces the sensor structure design and material selection to improve the sensitivity and selectivity of the sensor. A sensor case was fabricated using a 3D printer, and an Ag reference electrode, and a Pt counter electrode were deposited and applied to a Polytetrafluoroethylene (PTFE) filter using PVD. The working electrode was also deposited on a PTFE filter using vacuum filtration, and an electrochemical hydrogen sulfide gas sensor capable of measuring concentrations as low as 0.6 ppm was developed.

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.101-110
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• 2024

The purpose of this study is to analyze the effect of monitoring and feedback on walking activity using wearable devices on changes in body composition and metabolic syndrome factors in middle-aged woman. The subjects use a mobile interlocking wearable device for 6 month, feedback is provided through mobile app automatically transmitted step counter and walking activity. As a results, significantly difference shows on body weight, skeletal muscle mass, and body fat in statistically(p<.001). In changes of metabolic syndrome factor, systolic(p<.05), fasting flucose(p<.01), abdominal circumference(p<.001), TC(p<.001), and LDL-C(p<.05) are significantly difference. In conclusion, wearable devices that can be conveniently applied is an effective tool to increase walking activity and prevent metabolic syndrome of people with a sedentary lifestyle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4721-4726
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• 2010

The performance characteristics of water-chilling heat pump using CO2 for the control of inverter frequency was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter flow type heat exchangers with concentric dual tubes, which are made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2.4m length. The experimental results summarize as the following: for constant inlet temperature of evaporator and gas cooler, as mass flow rate, compression ratio and discharge pressure increases with the inverter frequency. And heating capacity and compressor work increases, but coefficient of performance(COP) decreases with the inverter frequency of compressor. As inlet temperature of secondary fluid in the evaporator increases from $15^{\circ}C$ to $25^{\circ}C$, compression ratio and compressor work decreases, but mass flow rate, heating capacity and COP increases with the inverter frequency of compressor. The above tendency is similar with performance variation with respect to the variation of inverter frequency in the conventional vapor compression refrigeration cycle.

• Journal of the Korean Home Economics Association
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• v.20 no.3
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• pp.85-102
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• 1982

The current employment status among young home economists and perspectives in occupations for prospective Home Economics graduates were explored in this study which utilized information from 17 to 21 colleges in Korea and colleges in the United States during the five years of 1977∼1981. The Home Economics content areas covered in this study were Clothing and Textiles, Foods and Nutrition, Housing and Interior Design, and Child Development and Family Life. The highest percentage of Korean graduates in Clothing and Textiles was employed either as teachers at the junior high school level or as designers in the clothing and textile industries. Quite a number of the graduates were engaged in further studies at the graduate level. Korean graduates with a master's degree were teaching at the college level and some had furthered their studies at the doctorate level either here or abroad. Koreans with a bachelor's degree in Foods and Nutrition held jobs as teachers in junior high school, dieticians at mass feeding institutions and hospitals, food scientists in food industries, and researchers in institutions. Those with a master's degree were teaching at the college level. Americans with a bachelor's degree worked as dieticians, supervisors in restaurants and institutions, extension workers, researchers at various facilities, teachers and clerks. Americans with a master's or doctorate degree were engaged in teaching at colleges or supervising at research or working as extension specialists. In general, Korean graduates were found to hold positions in less varied areas than their American counter-parts. Among forty-nine graduates those working in their professional field reported less sex discrimination that those working in other fields. The major area of employment in Housing and Interior Design or Home Management graduates in Korea was teaching while in the United States it was extension work, business, governmental work and teaching. It was suggested that in the future, career development in Korea be further explored to include extension service, research, social welfare, financial planning, business, free-lancing, funeral home, home-call, and correctional education. Interviews with executives from 6 business enterprises indicated that most of them were aware of the potential contribution home economists could make for their companies but they expressed a negative attitude towards women in general due to their short stay on the job. Jobs held by Child Development and Family Life majors with a bachelor's degree in Korea were mostly teaching positions in public, junior and senior high school. However, jobs such as nursery school teaching, working in clinical setting, business, and teaching at public, junior and senior high school predominated in the United states. Most Korean graduates with a master's degree were teaching in professional colleges while in the United Stated the job variation among the graduates was rather evenly distributed among teaching at college level, public and high school, nursery school and administration areas. Reports from 7 child development majors on the job indicated that they were paid less that secretarial workers. Only half of them were working in their major area and these expressed satisfaction with their work. Two thirds of the respondents indicated no sex discrimination. It was suggested that in the future Child Development and Family Life majors pursue employment in counseling, guidance, recreation, mass media, administration and outreach work as well as education, research and parent education in services for children, teen-agers, adults and families.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.146-156
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• 1998

Fly ash produced in coal combustion is a fine-grained material consisting mostly of spherical, glassy, and porous particles. A physical, morphological, and chemical characteristic of fly ash has been analyzed. This study may contribute to the data base of domestic fly ash, the improvement of combustion efficiency, ash recycling and ash collection in the electrostatic precipitator. The physical property of fly ash is determined using a particle counter for the measurement of ash size distribution and gravimeter. Morphological characteristic of fly ash is performed using a scanning electron micrograph and an optical microscope. The chemical components of fly ash are determined using an inductively coupled plasma emission spectrometry (ICP). The distribution of fly ash size was ranged from 15 to 25 $\mu$m in mass median diameter. Exposure conditions of flue gas temperature and duration within the combustion zone of the boiler played an important role on the morphological properties of the fly ash such as shape, relative opacity, coloration, cenosphere and plerosphere. The spherical fly ash might be generated at the condition of complete combustion. The size of fly ash was found to be increased the with particle-particle interaction of agglomeration and coagulation. Fly ash consisted of $SiO_2\;Al_2O_3\;and\;Fe_2O_3$ with 85% and carbon with 3~10% of total mass.

• Journal of Korean Public Health Nursing
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• v.13 no.1
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• pp.41-62
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• 1999

Recently the request of the patients to participate in the medical courses has been expanding due to elevated sense of right on the people's health. merchandised medical treatment by mass supply, human right declaration of the patients, generalized medical informations by the mass media and the change of human relation between the medical personnels and the patients. Under these phenomena the accident by the nurses have been increasing by the area of the nurses having been expanded and their independent roles having been increased. Such nursing accidents are the important subject which the professional occupation of the nurses has been facing but legal protective capability of the nurses has been very weak. Therefore this study has examined the degree of the experience of the nursing accident that happens in the clinical nursing scenes in the general hospital to provide the basic materials for the protection and the counter measures of the nursing accidents. The following is the conclusion based by the above examination. 1) The general characters of the subjects of this study is that they are mostly single in their twenties and graduate from nursing college. Their total clinical career is above 5 years$(44.8\%)$ and their current clinical parts' career is between 1-3 years$(40.1\%)$. So these facts suggest that most hospitals has taken the working rotation policy on nurses. 2) The level of nurses' knowledge on the nursing law is accurate partially but isn't it patially. So it is suggested that nurses need the accurate information and education about the nursing law. But the nurses' attitude is very approved of the establishment of a unilateral nursing law. 3) The relation between the demographic characters of the subjects and their attitudes on the nursing law shows that there is no significant differences except the relation between the attitude 6(the sufficient level of education on nursing law in formal education course) and age. total clinical career. 4) The perception of the nurses shows that the cause of the nursing accident has been due to the heavy work$(78.2\%)$. short of professional knowledge and skill$(60.2\%)$, discordance with Doctors. patients and patients' families. They report the accident to the head nurse first$(81.8\%)$ and within 30 minute$(75.1\%)$. The hour of nursing accident frequently happened is regardless of service hour with $49.4\%$ in response rate. the highest rate. and the nursing accident happens in the night more than the daytime. Even though most nurses think that they are themselves responsible for nursing accident. it is found that the chief cause of the nursing accident is due to the nurses' heavy work$(78.2\%)$. So the causes of nursing accidents is analysed. it may be suggested that the endeavor of hospital and nursing organizations to decrease nursing accidents is very important. 5) The coping patterns of patients with nursing accidents are mostly active attitude such as a violent words$(69\%)$. sue or accusation$(36.4\%)$, monetary compensation $(35.6\%)$ except a understanding cases$(38.7\%)$. But the coping patterns of hospitals with nursing accidents are mostly to investigate the accurate cause.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.1-21
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• 2021

Panax species have gained numerous attentions because of their various biological effects on cardiovascular, kidney, reproductive diseases known for a long time. Recently, advanced analytical methods including thin layer chromatography, high-performance thin layer chromatography, gas chromatography, high-performance liquid chromatography, ultra-high performance liquid chromatography with tandem ultraviolet, diode array detector, evaporative light scattering detector, and mass detector, two-dimensional high-performance liquid chromatography, high speed counter-current chromatography, high speed centrifugal partition chromatography, micellar electrokinetic chromatography, high-performance anion-exchange chromatography, ambient ionization mass spectrometry, molecularly imprinted polymer, enzyme immunoassay, 1H-NMR, and infrared spectroscopy have been used to identify and evaluate chemical constituents in Panax species. Moreover, Soxhlet extraction, heat reflux extraction, ultrasonic extraction, solid phase extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, acceleration solvent extraction, matrix solid phase dispersion extraction, and pulsed electric field are discussed. In this review, a total of 219 articles published from 1980 to 2018 are investigated. Panax species including P. notoginseng, P. quinquefolius, sand P. ginseng in the raw and processed forms from different parts, geographical origins, and growing times are studied. Furthermore, the potential biomarkers are screened through the previous articles. It is expected that the review can provide a fundamental for further studies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.1-10
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• 1972

Studies on the circulation and water masses in the continental shelf break region of the East China Sea are Summerized as follows : 1. The main stream of the Kuroshio flowing north-east near $29^{\circ}N\;Lat\;127^{\circ}E$ tong of the East China Sea in summer is narrow in width. Moving toward east, it becomes twice as wide in Tokora Strait, Japan. 2. In the main stream area of the Kuroshio, the surface Waters in the Upper layer (0-250m) are influenced by the coastal waters of China, and the counter current submerges under the surface water. Therefore, the mixing waters are found in its intermediate layer. 3. Water mass between Amami Island and the continental shelf of the East China Sea consists of main stream water, counter current water, gyration water and mixed water with coastal waters. 4. The maximum velocity of current in this waters was 139cm/sec. The volume transport was estimated approximately as $24.2\;\times\;10^6m^3/sec$. It was less than $33\;\times\;10^6m^3/sec$ in the region between Okinawa and continental shelf of the East China Sea. 5. Surface waters east of $29^{\circ}N\;Lat\;128^{\circ}E$ Long flows toward Amami Island, Okinawa Island, and Hachi Ju San Island, while those west of the region flow toward the Korea-strait, Cheju Island, coastal waters of Kyusyu, and the Pacific Ocean through Tokora Strait. The velocity of the current was estimated approximately as $0.3\~0.5$ miles per hour. 6. The bottom waters in the continental shelf break region flow toward the Korea Strait, Cheju Island and the coastal water of Kyusyu, while that of the continental shelf flows toward the Yellow Sea, 7, The characteristics of the Kuroshio water is changed remarkably by the mixing with the coastal water of China.