• Membrane Journal
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• v.8 no.4
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• pp.203-209
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• 1998

The cutting oil emulsion microfiltration was carried out on dead-end call and crossflow systems equipped with 0.22 $\mu$m GVHP Millipore and 0.2 m stainless steel Mott microfiltration membranes, respectivdy. The oil drop size in the emulsion was varied from 0.07 to 0.22 $\mu$m. Cake filtration(CFM) and standard pore blocking models(SPBM) were applied to predict the permeation flux. The permeation fluxes of 0.01 vol% oil emulsion followed CFM for dead-end system very well under the condition of 400 rpm and below 100 kPa. The SPBM was, however, suitable for the permeation flux at 400 rpm and above 150 kPa. The oil layer on the membrane surface was destroyed and reproduced repeatedly as operating pressure was suddenly changed from 60 to 200 kPa, and then returned to 60 kPa. Also, we estimated the critical entry pressure(CEP) which is changed from CFM to SPBM, and CEP for dead-end system was around 100 kPa. The CEP increased from around 100 to 150 kPa for the crossflow system as the oil concentration increased from 0.01 to 0.03 vol% when Reynolds number was 7080.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.384-386
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• 2014

Pseudomonas aeruginosa is an opportunistic pathogen that inhabits various natural and artificial environments, such as pathogenesis, water, soil and air. They can cause serious problems, such as pathogenic infection. In this study, 220 colonies were isolated from water and soil environment that assumed to be P. aeruginosa using a membrane filter method based on International Organization for Standardization (ISO/NP 16266). Identification of the isolates was determined by physiobiochemical characteristics using newly modified ISO method which includes the resistance to 1,10 phenanthroline test. Only one of 220 presumed P. aeruginosa strains isolated from effluence water using a drain swab was determined as P. aeruginosa-positive by the ISO/NP 16266 method. Subsequently, the resistance to 1,10 phenanthroline test, which was newly proposed by ISO in 2014 and applied in this study, was considered as more precise and improvable method for identification of P. aeruginosa.

• Journal of Technology Innovation
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• v.28 no.4
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• pp.127-150
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• 2020

The World Health Organization (WHO) declared the third pandemic in history after the Hong Kong flu and swine flu. The outbreak of Corona 19 dramatically reduced exchanges between countries, while rapid contagion created a time gap in economic fluctuations by country. In January 2020, the trade dispute between the US and China entered into a consensus phase, but the economic decoupling phenomenon caused by Corona 19 made it difficult for China to balance trade with the US and made it difficult to comply with the terms of the trade dispute agreement between the US and China. President Trump attributed the responsibility for the spread of Corona 19 to China, and pointed out that the cause of the economic downturn was the infringement of Chinese trade secrets and illegal copies, and protectionism arose. As a result, China protested fiercely, and the conflict with the United States deepened. The US has declared trade sanctions on Huawei and SMIC, which are key companies in China's semiconductor industry, and is predicting the risk of a disconnection of the semiconductor value chain between the US and China. The separation of the value chain of the semiconductor industry has the potential to have a big impact on the semiconductor industry, a structure that is highly specialized and monopolized by certain countries and companies in the value chain. This paper aims to deal with the risk of disconnection in the semiconductor value chain between the US and China reignited by Corona 19, the impact and change of the global semiconductor industry value chain, and the response strategies of Korean semiconductor companies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1844-1849
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• 2014

Existing measurement methods using microscopes or surface roughness measurement instruments for surface control in manufacturing die are low in their efficiency when they are applied in industrial fields due to structural problems. Therefore, it is very important to develop a measurement and analysis system which can enhance efficiency in the measurement of different-sized manufacturing dies and provide quality control regardless of location. This study aimed at the development of a portable surface measurement system to satisfy this need. This measurement system was designed and manufactured in such a way as to divide it into three parts: the Base, the Body, and the Optical system. As a result of testing the system, the surface roughness was measured with an accuracy between 94.9 and 99.9%, and the deviation in the measurement value of a circle was within $2{\mu}m$.

• Analytical Science and Technology
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• v.16 no.4
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• pp.325-332
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• 2003

To analyze co-planar PCBs in food, the isotopic dilution method by high resolution gas chromatography/high resolution mass spectrometry was applied. Among 209 PCB congeners, 12 congeners (#77, #81, #126, #169, #105, #114, #118, #123, #156, #157, #167 and #189) were chosen as target compounds that were toxic congeners re-assessed by WHO in 1998. Milk and milk products including cheese and butter were collected as food samples. Samples were homogenized, spiked with the known amount of the standard mixture and extracted. After extraction, extracts were cleaned up by sulfuric acid impregnated silica gel, purified on silica gel and alumina column chromatography and then analyzed by HRGC/HRMS. As results, the overall recoveries were ranged from 83% to 106% and the limit of detection was about 0.1 pg/g at signal/noise>3. Levels of targets in the selected food samples were 0.001~0.107 pgWHO-TEQ/g.

• Journal of Life Science
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• v.13 no.1
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• pp.83-89
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• 2003

To investigate the function of chloroplast small heat shock protein (HSP), transgenic tobacco plants (Nicotiana tabacum L, cv. SR-1) that constitutively overexpress the rice chloroplast small HSP (Oshsp26) were generated. Effects of constitutive expression of the Oshsp26 on thermotolerance were investigated with the chlorophyll fluorescence. After 5-min incubation of leaf discs at high temperatures, an increase in the Fo level, indication of separation of LHCII from PSII, was mitigated by constitutive expression of the chloroplast small HSP When tobacco plantlets grown in Petri dishes were incubated at $20^{\circ}C$/TEX> for 45 min and subsequently incubated at $20^{\circ}C$/TEX> leaf color of wild-type plant became gradually white and all plantlets were finally died. Under the conditions in which all the wild-type plants died, more than 80% of the transformants remained green and survived. It was also found that the levels of Oshsp26 protein accumulated in transgenic plants were correlated with the degree of thermotolerance. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery, as a results, increases thermotolerance of whole plant during heat stress.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.66-66
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• 2003

목적 : 선량측정의 정확성을 향상시키기 위하여 물 흡수선량 표준에 토대를 두고 있는 표준측정법, AAPM TG-51과 IAEA TRS-398, 이 발표되어 선량측정의 파라다임이 변화하고 있다. 본 연구에서는 이들 대표적인 표준측정법에 대하여 사용자 편의성을 고려하여 웹에 기반한 선량교정 프로그램을 개발하고자 한다. 대상 및 방법 : 미국의학물리학회 AAPM TG-51과 국제원자력기구 IAEA TRS-398 표준측정법에 선량교정 프로그램은 Microsoft IIS 6.0 웹서버와 .NET 플렛폼상에서 Visual Studio. NET 도구를 사용하여 개발하였다. 개발언어로는 C# 언어를 사용하였고 각 표준측정법에 대한 선량교정 작업서는 ASP. NET 페이지로 작성하였다. 웹페이지와 산량 교정 모듈을 분리하여서 개발 후 유지보수가 쉽게 설계하였다. 또한 기준점에서의 선량 계상에 사용하는 모든 물리적인 파라미터와 데이터는 데이터베이스에 저장하였다. 이로써 향후 수식체계의 변화 또는 물리적인 데이터의 변화로 인한 프로그램 수정이 최소화하도록 하였다. 결과 : 이들 표준측정법은 모두 물 흡수선량 교정인수에 토대를 두고 있으나 측정 조건 및 물리적인 자료 에 있어 약간의 차이를 보이고 있다. 그러므로 각 표준측정법간의 유사점 및 차이점을 비교 분석하기가 용이하였다. 그리고 개발된 프로그램을 이용하여 표준측정법에서 제시된 선량교정 작업서에 따라 선량 교정을 수행한 교정 결과 데이터를 XML 파일 형식으로 저장하여 이전의 측정 자료를 관리할 수 있게 하였다. 이 과거 측정 자료를 사용하여 출력 선량 교정의 변화 및 기타 중요한 물리적인 데이터 값의 변화를 분석할 수 있다. 결론 : 두 표준측정법에 대한 선량교정 프로그램은 사용자가 선호하는 표준측정법을 선택할 수 있고, 웹에 토대를 두고 있어 프로그램으로 전국 방사선종양학과의 방사선치료기기의 출력 및 물리적인 변화에 대한 자료를 비교 분석하기 용이하고 수작업으로 인해 발생할 수 있는 실수 및 오차를 줄일 수 있다. 또한 개발된 프로그램의 활용을 통하여 국내 실정에 적합한 물 흡수선량 표준에 기반한 표준측정법 개발에 토대를 마련하는데 있어 기여할 것으로 사료된다.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.18-25
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• 2002

One of the most serious concern in nuclear power plant piping maintenance is thickness reduction due to flow-accelerated corrosion (FAC). Since the FAC occurs under specific conditions of pH, dissolved oxygen, temperature, flow velocity, steam quality of the fluid and materials and geometry of the piping, a systematic approach is required for managing the FAC problem. In this study, construction of a secondary piping database, analyzing the FAC rate using the database and predicting the residual life was performed for a domestic CANDU nuclear power plant. Also FAC mechanism and factors affecting FAC were reviewed. By showing a case study on analysis for a pipe line between a separator and a flash tank, a procedure for managing FAC problem is suggested. The procedure proposed in this paper can be widely applied to the secondary piping of other domestic nuclear polder plants.

• Journal of Sericultural and Entomological Science
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• v.34 no.1
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• pp.49-56
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• 1992

Treatment of vinyl monomers onto silk fiber modifies the properties of the original silk fiber considerably. This field has been the subject of investigation by many workers using chemical and radiation initiation. Many studies on the reaction conditions, polymerization mechanism, physical properties and practical performances of methacrylamide-treated silk fiber have been continued. However, the polymerization mechanism has not been clearly revealed yet and this remains ambiguously whether the grafting is formed on fiber or not. In general, it has been accepted that free radicals were formed and vinyl monomers were polymerized in silk fibroin by graft polymerization mechanism, while active sties were varied by the types of monomer and initiator as well as by the reaction conditions. On the other hand, there is another argument on polymerization mechanism, in which monomers are polymerized and impregnated in the internal side of the fiber by homopolymerization. Though a large number of analytical methods are used to examine the polymerization mechanism of methacrylamide-treated silk fiber, the results on the basis of thermal analysis are merely reported in this paper. In differential scanning calorimetry (DSC) analysis, the thermal decomposition behaviors of the methacrylamie-treated silk fibers were determined and compared to those of the controlled silk fibers. DSC curves obtained from the methacrylamide-treated silk fibers showed double peaks at around 290$^{\circ}C$ (A peak) and 320$^{\circ}C$ (B peak) which are attributed to the thermal decomposition of the methacrylamide polymer and silk fibroin fiber, respectively. The temperature of A and B peak shifted to higher value with the increase of add-on. Also, the moisture regain of the treated silk fibers increased with add-on.

• 대한공업교육학회지
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• v.34 no.2
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• pp.321-330
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• 2009

This study presents the blow molding of injection stretch-blow molding process for PET bottle. The numerical analysis of the blow molding of PET bottle is considered in this paper using CAE with a view to minimize the thickness difference. In order to determine the design parameters and processing conditions in blow molding, it is very important to establish the numerical model with physical phenomenon. In this study, a shell model with thickness has been introduced for the purpose and blow simulations with 3-type blow process condition are carried out. The simulations resulted in the thickness distribution in good agreement with the physical phenomenon. Also, from the result of numerical analysis, we appropriately predicted the thickness distribution along the PET bottle wall and Using the result of numerical analysis we apply the preform design and blow molding process condition for optimization.