• Steel and Composite Structures
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• v.32 no.6
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• pp.807-819
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• 2019

In recent earthquakes, the failure of ceiling systems has been one of the most widely reported damage and the major cause of functionality interruption in some buildings. In an effort to mitigate this damage, some scholars have studied a series of ceiling systems including plaster ceilings and mineral wool ceilings. But few studies have involved the backdrop metal ceiling used in some important constructions with higher rigidity and frequency such as the main control area of nuclear power plants. Therefore, in order to evaluate its seismic performance, a full-scale backdrop metal ceiling system, including steel runners and metal panels, was designed, fabricated and installed in a steel frame in this study. And the backdrop metal ceiling system with two perimeter attachments variants was tested: (i) the ends of the runners were connected with the angle steel to form an effective lateral constraint around the backdrop metal ceiling, (ii) the perimeter attachments of the main runner were retained, but the perimeter attachments of the cross runner were removed. In the experiments, different damage of the backdrop metal ceiling system was observed in detail under various earthquakes. Results showed that the backdrop metal ceiling had good integrity and excellent seismic performance. And the perimeter attachments of the cross runner had an adverse effect on the seismic performance of the backdrop metal ceiling under earthquakes. Meanwhile, a series of seismic construction measures and several suggestions that need to be paid attention were proposed in the text so that the backdrop metal ceiling can be better applied in the main control area of nuclear power plants and other important engineering projects.

• Advances in concrete construction
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• v.16 no.1
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• pp.59-68
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• 2023

In the pumping process, concrete moves along the pipe and experiences both pressure and shear. This changes the workability and flow characteristics of the concrete. However, the effect of pressure and shear on the change in properties of concrete during the pumping process has not yet been accurately identified. This study analyzed the effects of pressure and shear on the properties of concrete during pumping. For quantitative tests, lab-scale test equipment capable of simulating the pressure and shear applied to concrete during pumping was used. For one coarse aggregate type, two paste types, three mortar types, and five concrete types, the effects of pressure, shear, and shear under pressure conditions were examined by varying the maximum pressure (0 to 200 bar) and the rotational speed of the vane for shear (0 to 180 rpm). Under the maximum pressure condition of 200 bar, the water absorption of coarse aggregate increased by 0.62% and that of fine aggregate also increased. When the concrete was under pressure, significant changes (a reduction in a slump and an increase in viscosity and yield stress) compared with the effect of the elapsed time occurred owing to an increase in the water absorption of the aggregates. When both pressure and shear were applied to concrete, both the slump and viscosity decreased. As the rotational speed of the vane increased, changes in properties became significant. Shearing in the absence of pressure maintained the properties of concrete. However, shearing under pressure conditions caused a reduction in slump and viscosity.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.139-148
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• 2017

Ground subsidence caused by damaged water pipe and sewer is recently increasing due to the aging of city and pipeline in many city. Although many recent studies have verified characteristics of ground subsidence due to wastewater pipe breakdown, research about characteristics of ground subsidence due to water pipe is insignificant. subsidence due to water pipe is insignificant. This study aims to identify the ground failure mechanism caused by water and sewer pipe breakdown. Accordingly, we conducted an indoor model experiment to verify characteristics of ground subsidence considering characteristics of ground and ground failure. The water pipe pressure and velocity head was considered to find out ground subsidence mechanism. Also comparative analysis is conducted by analyzing relative density and fine-grain content considering embedded condition of water pipe. When the relative density and seepage pressure is low, small scale ground subsidence can occur, but when the conditions are opposite, ground subsidence occur in large scale and expands to ground level over time. Furthermore, it is acknowledgeable that ground cavity that is formed after soil run off due to seepage in deep earth, maintains steady strength and stays on the ground level for long period.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.4
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• pp.311-318
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• 2010

U. S. NRC Regulation Guide 1.52 regulating ESF ACS in nuclear power plants has been revised to revision 3. To apply reduction of operability test time, allowance of alternative challenge agents for in-place leak test of HEPA filters, and upgrade of Methyl Iodide penetration acceptance criterion in activated carbon performance test suggested in Reg. Guide 1.52(Rev.3) on Yonggwang units 5 and 6 ESF ACSes, technical feasibility study was carried out with on-site experiments as well as experiments with a lab-scale model. It was confirmed that the moisture in the system returned to the level before the test in 1 or 4 days even though the moisture was removed during the operability test lasting more than 10 hours. Therefore, it is appropriate to perform monthly operability test in 15 minutes just long enough to check the operability of equipment. To change challenge material for in-place HEPA filter leak test, size of aerosol, production rate, and leak detection capability were compared for DOP and PAO. It was concluded that PAO can be substituted for DOP in nuclear power plants. The upgrade of Methyl Iodide penetration acceptance criterion from 0.175 % to 0.5 % in active carbon filter bed deeper than 4 inches was to conform to the change of activated carbon performance test method to ASTM D3803(1989). It was confirmed that Methyl Iodide penetration acceptance criterion of 0.5 % under $30^{\circ}C$, relative humidity 95 % condition was conservatively good enough for testing performance of active carbon insitu. The licence change of Yonggwang units 5 and 6 has been completed based on this study.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.2
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• pp.17-29
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• 2020

The objective of this study was to find an optimum methane yield condition in anaerobic digestion of sewage sludge with microwave pretreatment. The pretreatment process was carried out using a lab scale industrial microwave unit (2,450 MHz frequency). The digestion efficiency of pretreated sludge was evaluated by biochemical methane potential (BMP) test. Box-Behnken design and Response Surface Analysis (RSA) were applied to determine the optimal combination of sludge mixing ratio (0 to 100%), power (400 to 1600 W), holding time (0 to 10 min) and pretreatment temperature (60 to 100℃). BMP test results showed that Volatile Solid (VS) removal efficiency was up to 48% at a condition of 0% for mixing ratio, 1600 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. Methane production was up to 832.3 mL/g VS_removed at a condition of 50% for mixing ratio, 1000 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. The results of the variance analysis (ANOVA) showed that the p-value of the power and pretreatment temperature among the independent variables were significant (p<0.05), and in particular, the pretreatment temperature significantly affected on the solubilization and methane production. The optimum condition for the maximum methane yield (847 mL/g VS_removed) was consist of 38.4% of mixing ratio, 909.1 W of power, 4.1 min of holding time, and 80℃ of temperature within the design boundaries.

• Women's Health Nursing
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• v.1 no.1
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• pp.119-137
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• 1995

Maternity nurses' roles are to find out women's various responses related to the health problems during pregnancy, to intervene adequate nursing and supports, and to help them adapt satisfactorily to new situation, such as hospitalization. The purposes of this study are : firstly, to inquire about women's emotional status, feeling of discomfort, and the nursing need during hospitalization because of discomfort, and the nursing needs during hospitalization because of the possibility of abortion by threatened and habitual abortion : secondly, to provide fundamental data for developing adequate nursing intervention and improving hospital management. The subjects of this study were 62 women who were hospitalized, visited out-patient clinic for follow-up, and stayed at home after discharge since August, 1993 from one hospital located in Seoul, from March 23 to April 13, 1994. The questionnaire was consisted of 21 items of emotion(Reliability Cronbach's alpa, .77), 19 items of feeling of discomfort(.79), and 21 items of nursing needs (.89), and nurses' performance according to nursing needs,(.90). These were measured by using Likert Scale and analyzed by using SPSS / $PC^+$ with the descriptive statistics, $X^2$-test, and ANOVA. Research findings are as follows : 1) The subjects' average age, hospitalized days, and gestational age are 32.2, 15.7, 12.9 by respectively. 2) 88.7% of the subjects are getting antepatal care, 66.1% are experiencing 1.75 times of spontaneous abortion, and 82.3% are nuclear family. 3) The Emotions were mainly comprized negative and subjective state of minds such as uneasiness, anxiety, and discomfort. The domains of emotions were related to 'fetus', 'herself', 'hospitalization', and 'husband's 'families', in rank. The highest scored item was "I, above anyone else, am mostly stressed from abortion." 4) The feelings of discomforts were firstly related to 'personal discomfort arising from absolute bed rest', 'meals provided', Usage of hospital, perse', 'health team', in rank. 5) The nursing needs frequently pointed out were 'Nurses kindly explain of me the purpose, method, and results of the lab. test', 'Nurses sincerely pay attention to my word in communication'. The least nursing needs were 'Nurses observe my feces and whether I have constipation or not'. 'When I can't move, nurses help me by holding my arms or pulling my bed'. 6) The highest performed items were 'Nurses observe whether I bleed or not', and 'Nurses give me drug with exact dose in time'. The least performed items was about hospital environment, such as 'Temperature, ventilation & humidity in the room should be controlled'. 7) Besides religion that is related to nursing need with statistically significant difference, none of general characteristics were related to emotion, feeling of discomfort, and nursing needs.

• Geophysics and Geophysical Exploration
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• v.16 no.2
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• pp.79-90
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• 2013

Geophysical investigation in non-destructive testing is economically less expensive than boring testing and providing geotechnical information over wide-area. But, it provides only limited geotechnical information, which is hardly used to the design. Accordingly, we performed electrical resistivity experiments on large scale of soil model to analyze the correlation between electrical resistivity response and soil water contents. The soils used in the experiments were the Jumunjin standard sand and weathered granite soil. Each soil particle size distribution and coefficient of uniformity of experimental material obtained in the experiments were maintained in a state of the homogeneous. The specifications of the model used in this study is $160{\times}100{\times}50$(cm) of acrylic, and each soil was maintained at the height 30 cm. The water content were measured using the 5TE sensors (water contents sensors) which is installed 7 ~ 8 cm apart vertically by plugging to floor. The results of the resistivity behavior pattern for Jumunjin standard sand was found to be sensitive to the water content, while the weathered granite soil was showing lower resistivity over the time, and there was no significant change in behavior pattern observed. So, it results that the Jumunjin standard sand's particle current conduction was better than the weathered granite soil's particle through contact with the distilled water. This lab test was also compared with the result of a test bed site composed of similar weathered soil. It was confirmed that these experiments were underlying research of non-destructive investigation techniques to improve the accuracy to estimate the geotechnical parameter.

• Sleep Medicine and Psychophysiology
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• v.17 no.2
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• pp.91-99
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• 2010

Objectives: Deficit schizophrenia (DS) constitutes a disease separate from non-deficit schizophrenia (NDS). The aim of the current study was to compare the quantitative EEG and low resolution electromagnetic tomography (LORETA) imaging between DS and NDS. Methods: This study was performed by 32 channels EEG for 42 schizophrenia patients who we categorized into DS and NDS using proxy instrument deficit syndrome (PDS). We performed the absolute power spectral analyses for delta, theta, alpha, low beta and high beta activities. We compared power spectrum between two groups using Independent t-test. Partial correlation test was performed with clinical parameters. Standardized LORETA (sLORETA) was used for comparison of cortical activity, and statistical nonparametric mapping (SnPM) was applied for the statistical analysis. Results: DS showed significantly increased delta and theta absolute power in fontal and parietal region compared with NDS (p<0.05). Power spectrum showed significant correlation with 'anergia' and 'hostility/suspiciousness' subscale of brief psychiatric rating scale (BPRS)(p<0.05). sLORETA found out the source region (anterior cingulate cortex/limbic part) that delta activity was significantly increased in DS (p=0.042). Conclusions: DS showed different cortical activity compared with NDS. Our results may suggest QEEG and LORETA could be the marker in differentiating between DS and NDS.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.1
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• pp.23-28
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• 2017

Purpose Recently, there has been increasing demands for clinical departments at Asan Medical center in Seoul. They want to see the results of lab tests about blood samples as soon as possible and to be reported to them on the day. As the main contents of the survey, we explained the goodness of Asan medical center's in vitro and the points to be improved. Based on this, it became an opportunity to create a positive image of In vitro laboratory. In addition, we could identify their specific requirements through the surveys. Materials and Methods In September 2016, a total of 14 questionnaire surveys were conducted for 49 clinical departments and outpatient nurses at Asan Medical center in Seoul. The survey consists of description questions to be able to express the intention of the individual and the questions made on the Likert 4 point scale. The main contents of 14 questions are composed of goodness of In Vitro laboratory and points to be improved. Results 62% answered that the best service in In Vitro laboratory was "good accuracy and reproducibility". On the other hand, as an inconvenience when requesting blood tests, 73% pointed out that "the result report time was long", which was recognized as a part to be improved. There are many contents that "The result of all tests is reported within 2 hours" on the day of the examination. In the question - 'Are there some examination results which do not coincide well with clinical observations?', 55 of 56 people answered "no". Above all, the majority answered that waiting for re-examination results is too long. This problem must be causing discomfort to the patients. Conclusion In order to improve these problems, the first thing is to increase the number of blood tests by using the current personnel, equipments and reagents to the fullest by item in Asan Medical Center's Nuclear medicine in vitro part. Secondly, in case of re-examinations, we use the "AMIS message" to show other clinical departments the reporting time. This methode improves the efficiency of work with nurses and increases satisfaction of custom service. Thirdly, the correlation was evaluated by selecting the test species that can be carried out by the shortening method. Currently, C-peptide and insulin are implemented in the reaction process to shorten 2 hours into 1 hour. Finally, we are considering purchasing new equipments for quick test results.

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.175-184
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• 2000

A lab-scale MF membrane reactor was installed to investigate the membrane permeability, characteristics of membrane fouling at each conditions, and quality of permeate (liquid livestock manure) in the separation of solid-matters using membrane. Experiment was divided three filtration type such as follows; continuous filtration, gravity filtration, and intermittent filtration. As a result of experiment, flux 1 LMH was maintained for 7days, and trans-membrane pressure(TMP) was increased gradually under 10cmHg, but it was increased immediately after 10cmHg, respectively. However, the flux was increased, the Tmax was decreased exponential more and more. During the pure-flux test, most of the fouling of membrane was reversible. At the gravity filtration, permeate could be obtained as 1.75 LMH for 3.5days without any other electronic pressure. As an investigation of membrane surface, this study could be decided that the reason of fouling at the lower flux (Run 1 and 2) was attached matters in membrane surface, but at the higher flux (Run 4-6) was concentration polarization.