• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.38-42
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• 2003

The use of VPI impregnated mica tape as high voltage insulation for large rotating electric machines requires a careful balance of processes and materials to obtain the desired electrical, mechanical and thermal characteristics. The stator insulation systems such as epoxy bonded high voltage mica tape have been produced for many years. One such system employing an epoxy and anhydride impregnating resin developed by Hyundai Heavy Industries, Co. (hereafter, HHI), to satisfy customer requests for an epoxy bonded insulation system. HHI applies the following electrical and thermal evaluations such as dielectric breakdown, voltage endurance, dissipation factor vs. temperature, isothermal weight loss, and so on. A detailed laboratory evaluation can describe specific physical limitations for an insulation system and permit development of long-term operation guidelines that permit full utilization of the proposed system. HHI has found these evaluations very helpful in qualifying insulation system for the repair of both large motors and generators.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.481-486
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• 2017

This paper aims to evaluate the characteristics of direct and indirect effluents'toxicity level and difference between two test durations (24 h and 48 h) of test method. The proportion of the indirect effluent samples which exceeded the ecotoxicity permit limitations (TU 1 or TU 2) showed more than 2 times higher than that of direct effluent samples. However, effluent toxicity of Wastewater Treatment Plants (WTPs) indicated less than TU 1 regardless of influent toxicity. From this results, treatment process was thought to have a good efficiency. WTP Salinity was very similar between influent and effluent. This trend could be reconfirmed by the component ratio of ion concentration between them and $Na^+$, $SO_4^{2-}$, $C^-$ lions which have a greater percentage than other ions. In addition, in case of high salinity, toxicity value also showed high level. To judge from above results, indirect effluents which were exempted from application of ecotoxicity standards, may need a new effluent limitations regardless of the treatment efficiency of WTP. According to circumstances, effective countermeasure may need to restrain the discharge of salinity-contained effluents which came from indirect-effluent factories. Test duration comparative study indicated that 48 h results were higher toxicity (exceeding rate of ecotoxicity criteria) than 24 h by the 5 to 5.4 percentage. 24 h test duration seemed to be useful in case of rapid detection, whereas 48 h test method could be applied for reinforcement of ecotoxicity regulatory system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.211-212
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• 2023

Building Information Modeling (BIM) design has been mandatory in Korea since 2016, and it has been gradually expanding in the industry, with a slow attempt to apply it in remodeling constructions. This is because Korea is facing a situation where many buildings are over 30 years old and require remodeling or reconstruction. The remodeling industry is also a growing market, as it saves construction time and cost compared to reconstruction. BIM is an ideal technology element for a competitive remodeling construction, as remodeling constructions face a complicated construction process from the start, including demolition, maintenance, and reinforcement to save the change process. However, there are still limitations in applying BIM to remodeling constructions, due to considerations of the existing building and the complicated requests of the inhabitants. BIM still has technical and environmental limitations for general use. In this study, I analyzed BIM application cases from existing studies and suggest what improvement points should be strengthened.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.237-249
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• 2016

There are constraints on truck weight, axle configurations and size imposed by departments of transportation around the globe due to structural capacity limitations of highway pavements and bridges. In spite of that, freight movers demand some vehicles that surpass the maximum size and legal weight limits to use the transportation network. Oversized trucks serve the purpose of spreading the load on the bridge; thus, reducing the load effect on the superstructure. For such vehicles, often a quick structural analysis of the existing bridges along the traveled route is needed to ensure that the structural capacity is not exceeded. For a wide vehicle having wheel gage larger than the standard 1830 mm, the girder distribution factors in the design specifications cannot be directly used to estimate the live load in the supporting girders. In this study, a simple approach that is based on finite element analysis is developed by modifying the AASHTO LRFD's girder distribution factors for slab-on-steel-girder bridges to overcome this problem. The proposed factors allow for determining the oversized vehicle bending moment and shear force effect in the individual girders as a function of the gage width characteristics. Findings of the study showed that the relationship between the girder distribution factor and gage width is more nonlinear in shear than in flexure. The proposed factors yield reasonable results compared with the finite element analysis with adequate level of conservatism.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.1-9
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• 2010

Technology-Based Effluent Limitations (TBELs) is a permit limits for a pollutant that is based on the capability of a treatment technology to reduce the pollutant to a certain concentration. Widely practiced for regulations of industrial wastewater in US, TBELs has been accepted as an effective means that can achieve balanced goals between complete elimination of pollutants discharge and economic feasibility for industries. The review of TBELs application in US and the applicability of TBELs to the domestic industry categories was given in three papers. In the first paper, the development and practices of TBELs in US were reviewed including case studies. The developments of TBELs in US in the four major categories, the metal products & machinery, the petroleum refining, the porcelain enameling and the meat & poultry products were reviewed. The applicability of TBELs to the domestic industrial categories was also assessed. In the second paper, the pollution loads analysis for domestic industrial wastewater was conducted based on risk assessment indicator using Toxic Weighting Factors (TWFs). This is an essential part to determine the priority of TBELs application for the domestic industrial categories. In the last paper, the application of TBELs to the domestic industries was demonstrated through a case-study for the pulp/paper/paperboard category. Direct application of TBELs of US into the Korean regulation system may not be desirable because the specific goals and the environment for the regulations for the two countries may not be identical. For example, unlike US, Korea does not adopt the individual permit system for pollution sources. However, among the unproductive and exhaustive controversies over the uniform regulations regardless of the industrial categories in Korea, the introduction of the principles of TBELs are inevitable and more extensive study for applications of TBELs optimized for Korean regulation system will be necessary.

• Korean Journal of Biological Psychiatry
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• v.6 no.2
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• pp.161-169
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• 1999

There are a number of approaches in developing experimental models for depression, but there is no such thing as a best model for depressive syndrome. Animal models are subject to the obvious limitations inherent in the assumption that human psychopathology can be represented accurately in lower animals. Recently, the concern increasingly is to develop a variety of experimental paradigms in animals to study selected aspects of human psychopathology, and animal models should be understood as basically experimental preparations that are developed to carry out these objects. Therefore, a battery of a variety of animal models should be applied to permit detailed pathophysiological studies and to develop new antidepressant treatments. Animal models of depression basically consider behavioral isomorphism with the human depression a plus, but not a req-uirement, and the model behavior should be defined operationally in order to be reproduced reliably by other researchers and be responsive to those agents possessing demonstrated clinical efficacy in human depression. In conclusion, animal models of depression have played a significant role in elucidating pathophysiology of depression and developing current treatments for depression, but there is no single comprehensive model for depression until now. Each of the proposed animal model has its advantages and limitations. In other words, certain paradigms are suitable for studying certain phenomena, whereas others are more suitable for studying other aspects. The best model for depression depends upon what the question is.

• Clinical Endoscopy
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• v.51 no.6
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• pp.541-546
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• 2018

Recent advances in cholangiopancreatoscopy technology permit image-enhanced endoscopy (IEE) for pancreatobiliary diseases. There are limitations in endoscopy performance and in the study of the clinical role of IEE in bile duct or pancreatic duct diseases. However, currently available IEEs during cholangiopancreatoscopy including traditional dye-aided chromoendoscopy, autofluorescence imaging, narrow-band imaging, and i-Scan have been evaluated and reported previously. Although the clinical role of IEE in pancreatobiliary diseases should be verified in future studies, IEE is a useful promising tool in the evaluation of bile duct or pancreatic duct mucosal lesions.

• Textile Coloration and Finishing
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• v.9 no.3
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• pp.1-9
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• 1997

Plasma techniques permit modification of the surface layers of the substrate while maintaining its bulk properties. The use of plasma treatment on textile fibers and fabrics is very limited, however, the limitations, plasma treatments have been used to modify surface properties of textiles. In this study, multifunctional finish was performed by corona discharge technique for surface functionalization. Electron spectroscopy for chemical analysis(ESCA) was used to determine the ratios of carbon, oxygen, nitrogen, and phosphor at a 20$\AA$ sampling depth. K/S value and limiting oxygen index(LOI) value were used to obtain information on the effect of the finished fabrics. The mechanism of the flame retardancy was analyzed by the thermogravimetry-and the residue number. In ESCA, relative N1s intensity increased in case of mixtrure. The flame retardancy of the polyester and polyester/cotton fabrics treated with JA-6034 and JA-6050 was found to be operative mainly in the condensed phase mechanism. The multifunctional finish was better effect for the post treated finish agent.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.6 no.1
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• pp.108-115
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• 2006

The inherent biology of neural stem cells (NSCs) endows them with capabilities that not only circumvent many of the limitations of other gene transfer vehicles, but that enable a variety of novel therapeutic strategies heretofore regarded as beyond the purview of neural transplantation, Most neurodegenerative diseases are characterized not by discrete, focal abnormalities but rather by extensive, multifocal, or even global neuropathology. Such widely disseminated lesions have not conventionally been regarded as amenable to neural transplantation. However, the ability of NSCs to engraft diffusely and become integral members of structures throughout the host CNS while also expressing therapeutic molecules may permit these cells to address that challenge. Intriguingly, while NSCs can be readily engineered to express specified foreign genes, other intrinsic factors appear to emanate spontaneously from NSCs and, in the context of reciprocal donor-host signaling, seem to be capable of neuroprotective and/or neuroregenerative functions. Stem cells additionally have the appealing ability to "home in" on pathology, even over great distances. Such observations help to advance the idea that NSCs - as a prototype for stem cells from other solid organs - might aid in reconstructing the molecular and cellular milieu of maid eve loped or damaged organs.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.188-192
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• 2007

The biochemical oxygen demand (BOD) test is widely used to determine the pollution strength of water, to evaluate the performance of wastewater treatment plants and to judge compliance with discharge permits. However, nitrification is a cause of significant errors in measuring BOD, particularly when a large population of nitrifying organisms is existing in water such as effluents from biological treatment plants. In order to investigate the amount of nitrogenous oxygen demand (NOD), BOD with and without inhibitor was measured as samples in the biological treatment plants. About 81% of effluent BOD from the biological treatment plant used in this experiment was comprised of NOD. In the case of influents, the NOD accounted for about 9% of BOD. The inhibited 5-day BOD (Carbonaceous BOD) test must be considered in evaluating the performance of wastewater treatment plant and judging compliance with discharge permit limitations.