• Progress in Superconductivity and Cryogenics
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• v.9 no.2
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• pp.23-26
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• 2007

The influence of water partial pressure in Metal-organic Deposition (MOD) method was investigated on the texture and the morphology of $YBa_2Cu_3O_{7-x}$ (YBCO) films grown on the buffered metal tapes. The water partial pressure was varied from 4.2% up to 10.0% with the other process variables, such as annealing temperature and oxygen partial pressure, kept constant. In this work, the fluorine-free Y & Cu precursor solution added with Sm was synthesized and coated by the continuous slot-die coating & calcination step. The next annealing step of the YBCO films was done by the reel-to-reel method with the gas flowed vertically down. From the x-ray diffraction analysis, the un-reacted phase like $BaF_2$ peak was found at the water partial pressure of 4.2%, but $BaF_2$ peak intensity is much reduced as the water partial pressure is increased. However, the higher water partial pressure of about 10% in this experiment leads to the poor crystallinity of YBCO films. The morphologies of the YBCO films were not different from each other when the water partial pressure was varied in this work. The maximum critical current density of 3.8MA/$cm^2$ was obtained at the water partial pressure of 6.2% with the annealing temperature of 780$^{\circ}C$ and oxygen partial pressure of 500ppm.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.2
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• pp.101-127
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• 2017

Even with the most advanced aviation technology benefits, aircraft accidents are constantly occurring while air passenger transportation volume is expected to double in the next 15 years. Since it is not possible to secure aviation safety only by the post aircraft accident safety action of accident investigations, it has been recognized and consensus has been formed that proactive and predictive prevention measures are necessary. In this sense, the aviation safety management system (SMS) was introduced in 2008 and has been carried out in earnest since 2011. SMS is a proactive and predictive aircraft accident preventive measure, which is a mechanism to eliminate the fundamental risk factors by approaching organizational factors beyond technological factors and human factors related to aviation safety. The methodology is to collect hazards in all the sites required for aircraft operations, to build a database, to analyze the risks, and through managing risks, to keep the risks acceptable or below. Therefore, the improper implementation of SMS indicates that the aircraft accident prevention is insufficient and it is to be directly connected with the aircraft accident. Reports of duty performance related hazards including their own errors are essential and most important in SMS. Under the policy of just culture for voluntary reporting, the guarantee of information providers' anonymity, non-punishment and non-blame should be basically secured, but to this end, under-reporting is stagnant due to lack of trust in their own organizations. It is necessary for the accountable executive(CEO) and senior management to take a leading role to foster the safety culture initiating from just culture with the safety consciousness, balancing between safety and profit for the organization. Though a Ministry of Land, Infrastructure and Transport's order, "Guidance on SMS Implementation" states the training required for the accountable executive(CEO) and senior management, it is not legally binding. Thus it is suggested that the SMS training completion certificates of accountable executive(CEO) and senior management be included in SMS approval application form that is legally required by "Korea Aviation Safety Program" in addition to other required documents such as a copy of SMS manual. Also, SMS related items are missing in the aircraft accident investigation, so that organizational factors in association with safety culture and risk management are not being investigated. This hinders from preventing future accidents, as the root cause cannot be identified. The Aircraft Accident Investigation Manuals issued by ICAO contain the SMS investigation wheres it is not included in the final report form of Annex 13 to the Convention on International Civil Aviation. In addition, the US National Transportation Safety Board(NTSB) that has been a substantial example of the aircraft accident investigation for the other accident investigation agencies worldwide does not appear to expand the scope of investigation activities further to SMS. For these reasons, it is believed that investigation agencies conducting their investigations under Annex 13 do not include SMS in the investigation items, and the aircraft accident investigators are hardly exposed to SMS investigation methods or techniques. In this respect, it is necessary to include the SMS investigation in the organization and management information of the final report format of Annex 13. In Korea as well, in the same manner, SMS item should be added to the final report format of the Operating Regulation of the Aircraft and Railway Accident Investigation Board. If such legal and institutional improvement methods are complemented, SMS will serve the purpose of aircraft accident prevention effectively and contribute to the improvement of aviation safety in the future.

• Economic and Environmental Geology
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• v.22 no.2
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• pp.151-166
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• 1989

A study of rare-earth mineralization in Kyemyungsan metasedimentary formation of Precambrian Ogcheon Group was carried out in the Mt. Eore Area near Choongju City based on the thorium (Th) and uranium (U) count data of geophysical airborne survey. This rare-earth mineralization was found in the magnetite-bearing banded quartizite which contains diagnostically some amounts of the metamict allanite. The brown colored allanites are distributed as aggregates of fine grains and sometimes banded structures with magnetite (inter growth) along the banding. The ore bed is displaced by the small faults and granite intrusions, and separated 5 ore blocks. The dimensions of the outcrop are 50-80 m in width, 1,500 m in length with the strike of $N70-80^{\circ}E$ and dip of $50-80^{\circ}NW$. In the field, the values of total gamma ray count of GR-101A scintillometer were able to measure more than 400 cps and maximum 1,500 cps, which data are coincided with the values of GR-310 gamma ray spectrometer and the gamma ray count of well logging data. The chemical compositions of the allanites from EPMA data are ranged from$\sum^{TR_2O_3}$ 18.57% to 26.00%, and the cerium oxides ($Ce_2O_3$) of allanite are positive relation with $La_2O_3$, MgO, FeO, MnO and negative relation with $SiO_2$, $Al_2O_3$, $Nd_2O_3$. The result of Neutron Activation Analysis (N.A.A.), Multi-Channel Analysis (M.C.A.) and wet chemistry of 25 outcrop samples for the elements of REE, Zr, U, Th shows strong anomalies. The good correlation elements with the thorium (Th) are the elements of La, Ce, LREE, $TR_2O_3$, Pr, Sm, Yb, Lu by the increasing order.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.365-370
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• 2003

The phase development process of $Ba_2$ $Ti_{9}$ $O_{20}$ ceramics is not clearly known and frequently accompanies second phases which deteriorate dielectric properties. In synthesizing $Ba_2$ $Ti_{9}$ $O_{20}$ ceramics, in order to trace the reaction sequence during conventional solid-state reaction in BaO-Ti $O_2$ system, different barium sources of BaC0$_3$ and BaTi0$_3$ precursor were used as starting materials. From the analysis of XRD patterns, different secondary phases could be identified depending on the barium source used, which might mean that the equilibrium phases in BaO-Ti $O_2$ system are very difficult to be synthesized. Because the BaTi0$_3$ precursor provides short diffusion paths of ions, the system revealed less secondary phases during solid state reaction. In synthesizing BaO-xSm$_2$0$_3$-4.5Ti0$_2$ system using different barium sources, different secondary phases were developed also. Microstructure and dielectric properties were examined and discussed in terms of secondary phase development.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2046-2050
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• 2008

현재까지 우리나라에서 주로 사용되고 있는 2차원 흐름 해석 모형은 미연방 도로국(U.S. Federal Highway Administration)과 연계하여 Brigham Young University에서 개발된 SMS(Surface-Water Modeling System)모형이다. SMS모형 중 이송 확산 모형으로는 RMA-4가 포함되나 이 모형은 최신 수치기법을 반영하지 못하는 등의 문제점들로 인해 실제 물리적 현상을 모의에 있어서 한계를 가지고 있다. 따라서 물리적 현상에 대한 적절한 모의를 위해 여러 개선과정을 거쳐 RAM4가 개발되었다. 본 연구를 위해 점적분 유사량 측정기(P-61)와 대하천 유속계를 사용하여 대상구간의 SS자료 및 유속의 2차원적 분포를 취득하였고, SMS의 Pre-processing 기능을 이용하여 유한요소망을 구성하였다. 구성된 유한요소망과 흐름모형인 RMA-2를 사용하여 대상구간의 유속장을 모의하였다. 이때 모의된 유속장과 현장에서 취득한 유속분포를 비교하여 RMA-2를 검증하였고, SS자료와 RAM4로 모의된 농도장을 비교하여 RAM4를 검증하였다. 검증된 두 모형을 바탕으로 대상 구간에서 다량의 점오염원이 투입되는 가상의 시나리오를 선정 및 적용하여 오염물 이송 및 확산 거동에 대해 살펴보았다. 본 연구의 대상 하천은 형산강으로써, 유역 내에 경주시와 포항시가 위치하고 이 두 도시를 잇는 산업도로가 형산강 본류 위를 지나고, 또한 두 도시를 관류하고 있어 다른 국가하천과 마찬가지로 지속적이고 안정적인 수질관리가 필요한 하천이다, 모의구간은 형산강 본류 중 No. 68(안강 수위관측소 상류 약 350 m)에서 No. 48(부조 수위관측소 하류 약 200 m)까지로서, 약 4.3 km 구간을 모의 하였다. 모의구간 시점에서 약 0.35 km 지점에 산업도로의 일부분인 강동대교, 0.98 km 지점에 왕신천 유입, 1.35 km 지점에 수중보, 1.8 km 지점에 국당1교, 3.2 km 지점에 국당2교가 위치하며 구간 내에는 만곡 및 사행, 특히 수중보 전 후로 사주가 발달해있어 2차원 흐름 및 이송확산 모의에 적합하다고 판단되었다.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.705-715
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• 2013

The response of the freshwater microalga Chlorella vulgaris to mercuric ion ($Hg^{2+}$) stress was examined using chlorophyll a fluorescence image analysis and O-J-I-P analysis as a way to monitor the toxic effects of mercury on water ecosystems. The levels of photosynthetic pigments, such as chlorophyll a and b and carotenoids, decreased with increasing $Hg^{2+}$ concentration. The maximum photochemical efficiency of photosystem II(Fv/Fm) changed remarkably with increasing $Hg^{2+}$ concentration and treatment time. In particular, above $200{\mu}M\;Hg^{2+}$, considerable mercury toxicity was seen within 2 h. The chlorophyll a fluorescence transient O-J-I-P was also remarkably affected by $Hg^{2+}$; the fluorescence emission decreased considerably in steps J, I, and P with an increase in $Hg^{2+}$ concentration when treated for 4 h. Subsequently, the JIP-test parameters (Fm, Fv/Fo, RC/CS, TRo/CS, ETo/CS, ${\Phi}_{PO}$, ${\Psi}_O$ and ${\Phi}_{EO}$) decreased with increasing $Hg^{2+}$ concentration, while N, Sm, ABS/RC, DIo/RC and DIo/CS increased. Therefore, a useful biomarker for investigating mercury stress in water ecosystems, and the parameters Fm, ${\Phi}_{PO}$, ${\Psi}_O$, and RC/CS can be used to monitor the environmental stress in water ecosystems quantitatively.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.257-265
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• 2014

The aim of this study was to establish the appropriate guidelines in the sedation techniques and to organize the continuing education programs for the sedation in future under the direction of Committee on Sedation, Education and Research under the Korean Academy of Pediatric Dentistry(KAPD). The surveys on the sedation technique were performed on 111 organizations which practices the sedation and responded to the survey via online and e-mail by February 2014. The collected survey were analyzed. The purpose of sedation was mainly to manage the children's behavior and its uses were primarily on 3~4 years old children. The most frequent duration of treatment was 1~2 hours to treat both maxillary and mandible. The preferred dosages of sedative drugs were chloral hydrate(CH) 50~70 mg/kg, hydorxyzine(Hx) 1~2 mg/kg, and intramuscular midazolam(Mida IM) 0.1~0.2 mg/kg. The preferred combination of the sedative drugs were CH + Hx + $N_2O/O_2$(67.6%), CH + Hx + Mida submucosal administration (SM) + $N_2O/O_2$(29.7%), and Mida IM + $N_2O/O_2$(23.4%). The administration of additional sedatives was carried out at 48%, mainly using Midazolam. 87.5% of the respondents experienced the adverse effects of the sedation such as vomiting/retching, agitation during recovery, subclinical respiratory depression, staggering, and etc. Among them, only 20% periodically retrain the emergency management protocol. About the discharge criteria for patients after the sedation, the respondents either showed a lack of clear criteria or did not follow the recommended discharge criteria. 86% of the respondents expressed the interests in taking a course on the sedation and they wanted to learn mostly about the sedation-related emergency management, the safe dosage of the sedative drugs, and etc. The use of sedation in pediatric dentistry must be consider a patient's safety as top priority and each dentist must show the evidence of sound practices for the prevention of any possible medical errors. Therefore, KAPD must establish the proper sedation guidelines and it needs to provide the systematic technical training program of sedation-related emergency management for pediatric dentists.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.392-404
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• 2015

Objectives: This study measured and analyzed the concentrations of crystalline silica, elemental carbon and the contribution ratio of pollutants which influence environmental and respiratory disease around the Ansim Briquette Fuel Complex in Daegu, Korea. Methods: We analyzed the crystalline silica and elemental carbon in the air according to FTIR(Fourier Transform Infrared Spectroscopy) and NIOSH(National Institute of Occupation Safety and Health) method 5040, respectively. In addition, lead stable isotopes, and carbon and nitrogen stable isotopes were analyzed using MC-ICP/MS(Multi Collector-Inductively Coupled Plasma/Mass Spectrometer), and IRMS(Isotope Ratio Mass Spectrometer), respectively. Results: The concentration of crystalline silica in the direct exposure area around the Ansim Briquette Fuel Complex was found to be $0.0014{\pm}0.0005mg/Sm^3$, but not to exceed the exposure standards of the ACGIH(American Conference of Governmental Industrial Hygienists). In the case of the autumn, the direct exposure area was found to show a level 2.5 times higher than the reference area, and on the whole, the direct exposure area was found to have a level 1.4 times higher than the reference area. The concentration of elemental carbon in the direct exposure area and in the reference area were found to be $0.0014{\pm}0.0006mg/Sm^3$, and $0.0006{\pm}0.0003mg/Sm^3$, respectively. This study confirmed the contribution ratio of coal raw materials to residentially deposited dusts in the area within 500 meters from the Ansim Briquette Fuel Complex and the surrounding area with a stable isotope ratio of 24.0%(0.7-62.7%) on average in the case of carbon and nitrogen, and 33.9%(26.6-54.1%) on average in the case of lead stable isotopes. Conclusions: This study was able to confirm correlations with coal raw materials used by the Ansim Briquette Fuel Complex and the surrounding area. The concentration of some pollutants, crystalline silica, and elemental carbon emitted to the direct-influence area around the Ansim Briquette Fuel Complex were relatively higher than in the reference area. Therefore, we need to impose continuous and substantive reduction countermeasures in the future to prevent particulate matter and coal raw materials in the study area. It is time for the local government and authorities to prepare active administrative methods such as the relocation of Ansim Briquette Fuel Complex.

• Food Science and Preservation
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• v.23 no.5
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• pp.718-726
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• 2016

Sweet pumpkin paste (SPP) was fermented by Leuconostoc mesenteroides SM at $25^{\circ}C$ for 3 days for enhancing its physicochemical properties. SPPs with 5%, 10%, and 15% solid contents (SC) were fortified with 20% sucrose and 0.5% yeast extract. The unfermented SPP with 15% SC indicated L, a, and b color values of 25.02, 4.66, and 13.35, respectively, and a consistency index of $48.6Pa{\cdot}s^n$. During the 3 days of fermentation, both the a and b color values decreased slightly, whereas the consistency index increased to $188.8Pa{\cdot}s^n$, giving the fermented product a pudding-like consistency. This fermented SPP (15% SC) showed the highest acid production and viable cell counts among samples, indicating pH 3.85, 1.30% acidity and $9.2{\times}10^8CFU/mL$ respectively. The added sucrose was completely utilized after 1 day of fermentation. After 3 days, the insoluble and soluble dextran contents were 8.9% and 4.5%, respectively. Furthermore, the contents of mannitol and fructose were 3.11% and 1.76%, respectively. Regarding the sensory evaluation, this fermented sample also indicated the highest color, taste and texture scores, and was the overall preferred sample. In conclusion, the fermented SPP with 15% SC was carotinoid-rich a wholesome pumpkin-based product that is rich in probiotics and lactic bacteria-produced mannitol and dextran, which gave the product an acceptable viscous pudding-like consistency and good organoleptic properties.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.381-391
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• 2007

A series of talus slope stability analyses were carried out using 2D FEM and 3D limit equilibrium methods for this study. The FEM analyses on Phase 2 were performed to delineate failure depths based on stress distributions for each slope. The results revealed that the failure surface exist in the colluvium layer of about 3-10 m thickness. Three dimensional models, derived from the FEM analyses and geological field survey, were made for the use in a 3D limit equilibrium analysis. The result shows that all the talus slopes are stable under dry condition, but unstable under saturated condition due to heavy rain.