• Title/Summary/Keyword: High current measuring

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Experimental Study on the Effects of Combustion Products on the Human Body and Suggestion of Law Revision (흡음재의 연소 생성물이 인체에 미치는 영향에 대한 실험적 연구 및 법률 개정 제언)

  • Kang, Jung Ki;Choi, Don Mook
    • Fire Science and Engineering
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    • v.33 no.4
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    • pp.28-34
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    • 2019
  • Regardless of the ignition source, the main factors affecting the spread of flames to the human body are combustibles. The sound absorption material, which is the finishing material used in music institutes and karaoke rooms, consists of polyurethane that generates a large amount of toxic gas with a high amount of combustion gases during a fire. Still, the current law does not require the use of impregnated finishing materials for tutoring services with less than 100 users. In this study, the rate of flame diffusion was measured using the MultiRaelite composite gas measuring instrument (target substance VOC, HCHO, SO2, CO2, CO, HCN, and NO2) for the collection of sound-absorbing materials installed in the actual music academy. The results showed that the toxic gas found in this experiment exceeded the allowable concentration of TWA (Time Weighted Average) and STEL (Short Term Exposure Limit). In addition, a comparative combustion test of the general sound absorber and non-combustion sound absorbing materials on the market showed wide differences in ignition and diffusion. Therefore, based on the results of the experiment, private institutes with less than 100 users should be mandated to use non-combustion sound absorbing materials.

Recognition of Seawater Intrusion Using Reference IP Technique (참조채널 유도분극탐사기술에 의한 해수침투대 인지)

  • Lee, Sang-Kyu;Hwang, Hak-Soo;Hwang, Se-Ho;Park, In-Hwa;Shin, Je-Hyun
    • Geophysics and Geophysical Exploration
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    • v.5 no.1
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    • pp.56-63
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    • 2002
  • Tracing the history of study, problems of seawater intrusion are commonly investigated with electrical techniques because seawater saturated zone is indicative of the low resistivity anomaly. There we, however, silt and mud layers in the western and southern coastal areas of Korea, so we may make a mistake in case we determine seawater intrusion only with resistivity survey. Hence, reference IP survey was carried out in Kimje, Jeollabuk-Do and Youngkwang, Jeollanam-Do in order to decide whether or not the area is under the influence of seawater intrusion. With the use of a electric field cable to minimize EM coupling, we obtained more accurate results by appling reference If technique measuring simultaneously wavelet of current as well as potential. With the aid of reference IP technique, it is possible that we can exactly evaluate seawater intrusion by discriminating seawater saturated area (no IP effect) from very highly conductive layer composed of clay mineral (high IP effect).

A Linear Change of Leakage Current and Insulation Resistance of 22 kV Cables (22 kV 케이블의 누설전류 및 절연저항의 선형적 변화)

  • Um, Kee-Hong;Lee, Kwan-Woo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.3
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    • pp.169-173
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    • 2015
  • This study is to predict the life exponent by measuring, over 7 years, the insulation resistance of high-voltage cables in 22 kV operation for 13 years. We found out the lifetime index in order to determine the time-dependent trend of deteriorating performance of power cables. The insulation resistances decreased according to elapsed time. We found that: the initial measurements of the cable systems were in agreement with the deterioration properties of the Arrhenius Law. By analyzing the life curve of the cable system, we also verified that the value of the life exponent (n) in the v-t characteristics defined by Weibull distribution has values from 10 to 11. When designing the cable system, the initial value of life exponent was chosen as 9 without any grounding. We have verified that the theoretical grounding based on the design safety of n=9 was actually the best one available. In the short term, we apply our research result to the diagnosis and evaluation of the power cables. In the long run, however, we plan to reduce the cost of the installation and management of cable systems in operation at power stations.

A Study on the Wireless Ship Motion Measurement System Using AHRS (AHRS를 이용한 무선 선체 운동 측정 시스템에 관한 연구)

  • Kim, Dae-Hae;Lee, Sang-Min;Kong, Gil-Young
    • Journal of Navigation and Port Research
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    • v.37 no.6
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    • pp.575-580
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    • 2013
  • The IMU(Inertial Measurement Unit) which is the expensive equipment has been used as a special limited area, usually in measurement of posture of applying to the areas of ship, submarine, aircraft and military equipment application. However, in the current situation, MEMS AHRS technology can replace the high-priced IMU in MEMS AHRS selected application field. In this paper, wireless hull motion measurement system was suggested for measuring key elements of ship's movement such as rolling, pitching and yawing using gyro, acceleration and magnetic sensors of AHRS. In order to reduce the error such as instantaneous acceleration, effects and vibration of geomagnetic, we have adopted the sensors equipped with Kalman filtering. The Wireless hull motion measurement system using AHRS sensors was tested in actual ship and it could easily be applied in limited installation circumstances of the ship. In the future, this system can be useful in the navigation safety and marine accident analysis by using with ship equipment such as INS or VDR in the maritime.

Police Officers' Cognitions of Police Investigation Specialization (수사경과제에 대한 경찰공무원의 인식)

  • Choi, Mu-Chan
    • The Journal of the Korea Contents Association
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    • v.9 no.6
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    • pp.289-299
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    • 2009
  • This study set out to analyze the perceptions of investigative police officers and division police officers regarding Police Investigation Specialization, which had been in effect for four years, identify the problems, and search for alternative policies. The results led to the following alternative policies; first, the communication among the members should be facilitated by trading the jobs between investigative policemen and division members in certain percentage regularly, integrating job education and special work, and developing diverse support programs for detective activities to provide them with opportunities to experience and understand investigation. The second suggestion concerns the investigation members' morale. There should be a range of measures to boost their moral such as allocating separate budget and personnel to support the investigation department and the treatment of major criminal and civil cases, giving each investigation team an office and investigation room to improve their working environment, readjusting the promotion ratio of Police Investigation Specialization to introduce a promotion system proper for each investigation's characteristics. The third suggestion is to secure job efficiency. It's required to reinforce the current short-term specialized education program to bring up practical and professional investigators, open the certification exam of professional investigators to all members so that every policeman can have their abilities recognized and approved as long as they have the demanded capabilities, and create a system of shedding off the members idle at work by reflecting low performance records when evaluating the members to decide who to dismiss from Police Investigation Specialization. And finally, it's important to divide duties rationally. The rationality of duties division can be guaranteed by setting the guidelines for direct handling for the team leader to help him devote himself to his duties, defining objective criteria of measuring investigation workload, and creating devoted systems and teams for simple and small accidents so that experienced investigators can deal with high-profile cases.

Relationship of the Institutes for Analyzing Requested Samples(IARS) among Working Environment Measuring Institutes(WMIs) and the Participation of the Non-mandatory Proficiency Test (작업환경측정시료의 분석수탁기관과 자율정도관리 참여와의 연관성)

  • Kim, Sungho;Kwon, Jiwoon;Cho, Hyunmin;Park, Hae Dong
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.31 no.2
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    • pp.111-118
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    • 2021
  • Objectives: The necessity of samples for analysis requested by working environment monitoring institutes (WMIs) has grown recently. The collection of samples of a few chemical substances requested by WMIs is allowed under the current occupational safety and health act in Korea, leading to an expansion of samples for analysis requested by institutes (SRIs). The objective of this study was to identify the number of institutes for analyzing requested samples (IARS), SRIs, and their participation in a non-mandatory proficiency test. Methods: Questionnaires were completed by all WMIs. The collected information was quantity of analysis equipment, sorting of chemicals from SRIs, and the number of SRIs. This was compared in terms of the participation in the non-mandatory proficiency test. Results: All WMIs in Korea responded to the survey, establishing a 100% response rate. There were 52 (29%) IARS among the 179 WMIs in Korea. The total number of samples of acid for ion chromatograph (IC) analysis requested by WMIs was 21,165, which is the most. Even the number of IARS for crystalline silicon oxide was less than other top-five IARS. The total amount of samples was 13,863, which was the second most. The calculated participation score for IARS was significantly higher than other WMIs (p<0.001). According to participation in the non-mandatory proficiency test by type of substance, such as crystalline silicon oxide and formaldehyde among IARS, the number of SRIs from those IARS was significantly higher than IARS that did not participate in the proficiency test (p<0.05). Conclusions: IARS had a high frequency of participation in the non-mandatory proficiency test and the number of SRIs at IARS participating in the proficiency test was higher among IARS. With the revision of the occupational health and safety act in Korea, the number of IARS participating in the non-mandatory proficiency test might increase.

A Study on Replica Restoration Methods through Scientific Analysis of Seongju Lee Family's Portraits (성주 이씨가(家) 초상화의 과학적 분석을 통한 모사복원방안 연구)

  • Jeong, Ji-Youn;Lee, Jang-Jon;Han, Min-su
    • Journal of Conservation Science
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    • v.38 no.3
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    • pp.201-216
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    • 2022
  • Materials and techniques used for two portraits (Jo-nyeon Lee and S ung-in Lee) of the Lee family from Seongju enshrined in Seongsan temple were scientifically analyzed, and based on the data, an optimal replica restoration method was designed. According to the expression technique investigation, both portraits were expressed mainly in line drawing, but there were differences in shoes, pupils, the color expression of flesh, overpainting, and traces of reinforcement. Pigment analysis revealed that a mixture of cinnabar and minium, organic pigment, azurite, malachite, lead white, and yellow pigment were used in common. In the case of Sung-in Lee's portrait, seokganju and atacamite were also used. In addition, comparison with the contemporaneous portraits of gentry showed that the portrait style at the time was found in the two portraits, but the singularity was modified differently there. Based on the scientific analysis, it was decided to replicate the old color restoration for Jo-nyeon Lee's portrait while for Sung-in Lee's portrait, it was decided to replicate the phenomenon. Detailed coloring techniques were presented by supplementing the expression techniques that are difficult to confirm visually using scientific data. In addition, by measuring the chromaticity of representative positions in the portrait for each color and presenting the color reference value calculated as the average value, the current color of the artifact can be replicated and restored based on the objective data as much as possible.

Modeling Residual Water in the Gas Diffusion Layer of a Polymer Electrolyte Membrane Fuel Cell and Analyzing Performance Changes (고분자 전해질막 연료전지의 기체확산층 내부 잔류수 모델링 및 성능변화해석)

  • Jiwon Jang;Junbom Kim
    • Applied Chemistry for Engineering
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    • v.35 no.1
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    • pp.16-22
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    • 2024
  • Polymer electrolyte membrane fuel cells have the advantage of low operating temperatures and fast startup and response characteristics compared to others. Simulation studies are actively researched because their cost and time benefits. In this study, the resistance of water residual in the gas diffusion layer (GDL) of the unit cell was added to the existing equation to compare the actual data with the model data. The experiments were conducted with a 25 cm2 unit cell, and the samples were separated into stopping times of 0, 10, and 60 minutes following primary impedance measurement, activation, and polarization curve data acquisition. This gives 0, 10, and 60 minutes for the residual water in the GDL to evaporate. Without the rest period, the magnitude of the performance improvement was not significantly different at the same potential and flow rate, but the rest period did improve the performance of the membrane electrode assembly when measuring impedance. By changing the magnitude of the resistance reduction to an overvoltage, the voltage difference between the fuel cell model with and without residual water was compared, and the error rate in the high current density region, which is dominated by concentration losses, was reduced.

A Study on Qulity Perceptions and Satisfaction for Medical Service Marketing (의료서비스 마케팅을 위한 품질지각과 만족에 관한 연구)

  • Yoo, Dong-Keun
    • Journal of Korean Academy of Nursing Administration
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    • v.2 no.1
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    • pp.97-114
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    • 1996
  • INSTRODUCTION Service quality is, unlike goods quality, an abstract and elusive constuct. Service quality and its requirements are not easily understood by consumers, and also present some critical research problems. However, quality is very important to marketers and consumers in that it has many strategic benefits in contributing to profitability of marketing activities and consumers' problem-solving activities. Moreover, despite the phenomenal growth of medical service sector, few researchers have attempted to define and model medical service quality. Especially, little research has focused on the evaluation of medical service quality and patient satisfaction from the perspectives of both the provider and the patient. As competition intensifies and patients are demanding higher quality of medical service, medical service quality and patient satisfaction has emerged as a critical research topic. The major purpose of this article is to explore the concept of medical service quality and its evaluation from both nurse and patient perspectives. This article attempts to achieve its purpose by (1)classfying critical service attibutes into threecategories(satisfiers, hygiene factors, and performance factors). (2)measuring the relative importance of need criteria, (3)evaluating SERVPERF model and SERVQUAL model in medical service sector, and (4)identifying the relationship between perceived quality and overall patient satisfaction. METHOD Data were gathered from a sample of 217 patients and 179 nurses in Seoul-area general hospitals. From the review of previous literature, 50 survey items representing various facets of the medical service quality were developed to form a questionnaire. A five-point scale ranging from "Strongly Agree"(5) to "Strongly Disagree"(1) accompanied each statement(expectation statements, perception statements, and importance statements). To measure overall satisfaction, a seven-point scale was used, ranging from "Very Satisfied"(7) to "Very Dissatisfied"(1) with no verbal labels for scale points 2 through 6 RESULTS In explaining the relationship between perceived performance and overall satisfaction, only 31 variables out of original 50 survey items were proven to be statistically significant. Hence, a penalty-reward analysis was performed on theses 31 critical attributes to find out 17 satisfiers, 8 hygiene factors, and 4 performance factors in patient perspective. The role(category) of each service quality attribute in relation to patient satisfaction was com pared across two groups, that is, patients and nurses. They were little overlapped, suggesting that two groups had different sets of 'perceived quality' attributes. Principal components factor analyses of the patients' and nurses' responses were performed to identify the underlying dimensions for the set of performance(experience) statements. 28 variables were analyzed by using a varimax rotation after deleting three obscure variables. The number of factors to be extracted was determined by evaluating the eigenvalue scores. Six factors wereextracted, accounting for 57.1% of the total variance. Reliability analysis was performed to refine the factors further. Using coefficient alpha, scores of .84 to .65 were obtained. Individual-item analysis indicated that all statements in each of the factors should remain. On 26 attributes of 31 critical service quality attributes, there were gaps between actual patient's importance of need criteria and nurse perceptions of them. Those critical attributes could be classified into four categories based on the relative importance of need criteria and perceived performance from the perspective of patient. This analysis is useful in developing strategic plans for performance improvement. (1) top priorities(high importance and low performance) (in this study)- more health-related information -accuracy in billing - quality of food - appointments at my convenience - information about tests and treatments - prompt service of business office -adequacy of accommodations(elevators, etc) (2) current strengths(high importance and high performance) (3)unnecessary strengths(low importance and high performance) (4) low priorities(low importance and low performance) While 26 service quality attributes of SERPERF model were significantly related to patient satisfation, only 13 attributes of SERVQUAL model were significantly related. This result suggested that only experience-based norms(SERVPERF model) were more appropriate than expectations to serve as a benchmark against which service experiences were compared(SERVQUAL model). However, it must be noted that the degree of association to overall satisfaction was not consistent. There were some gaps between nurse percetions and patient perception of medical service performance. From the patient's viewpoint, "personal likability", "technical skill/trust", and "cares about me" were most significant positioning factors that contributed patient satisfaction. DISCUSSION This study shows that there are inconsistencies between nurse perceptions and patient perceptions of medical service attributes. Also, for service quality improvement, it is most important for nurses to understand what satisfiers, hygiene factors, and performance factors are through two-way communications. Patient satisfaction should be measured, and problems identified should be resolved for survival in intense competitive market conditions. Hence, patient satisfaction monitoring is now becoming a standard marketing tool for healthcare providers and its role is expected to increase.

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Analysis of Amperometric Response to Cholesterol according to Enzyme-Immobilization Methods (효소고정화 방법에 따른 콜레스테롤 검출용 바이오센서의 전류 감응도 분석)

  • Ji, Jung-Youn;Kim, Mee-Ra
    • Journal of the East Asian Society of Dietary Life
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    • v.21 no.5
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    • pp.731-738
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    • 2011
  • Cholesterol is the precursor of various steroid hormones, bile acid, and vitamin D with functions related to regulation of membrane permeability and fluidity. However, the presence of excess blood cholesterol may lead to arteriosclerosis and hypertension. Moreover, dietary cholesterol may affect blood cholesterol levels. Generally, cholesterol determination is performed by spectrophotometric or chromatographic methods, but these methods are very time consuming and costly, and require complicated pretreatment. Thus, the development of a rapid and simple analysis method for measuring cholesterol concentration in food is needed. Multi-walled carbon nanotube (MWCNT) was functionalized to MWCNT-$NH_2$ via MWCNT-COOH to have high sensitivity to $H_2O_2$. The fabricated MWCNT-$NH_2$ was attached to a glassy carbon electrode (GCE), after which Prussian blue (PB) was coated onto MWCNT-$NH_2$/GCE. MWCNT-$NH_2$/PB/GCE was used as a working electrode. An Ag/AgCl electrode and Pt wire were used as a reference electrode and counter electrode, respectively. The sensitivity of the modified working electrode was determined based on the amount of current according to the concentration of $H_2O_2$. The response increased with an increase of $H_2O_2$ concentration in the range of 0.5~500 ${\mu}M$ ($r^2$=0.96) with a detection limit of 0.1 ${\mu}M$. Cholesterol oxidase was immobilized to aminopropyl glass beads, CNBr-activated sepharose, Na-alginate, and toyopearl beads. The immobilized enzyme reactors with aminopropyl glass beads and CNBr-activated sepharose showed linearity in the range of 1~100 ${\mu}M$ cholesterol. Na-alginate and toyopearl beads showed linearity in the range of 5~50 and 1~50 ${\mu}M$ cholesterol, respectively. The detection limit of all immobilized enzyme reactors was 1 ${\mu}M$. These enzyme reactors showed high sensitivity; especially, the enzyme reactors with CNBr-activated sepharose and Na-alginate indicated high coupling efficiency and sensitivity. Therefore, both of the enzyme reactors are more suitable for a cholesterol biosensor system.