• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.448-448
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• 2010

Magnetic random access memory (MRAM) has made a prominent progress in memory performance and has brought a bright prospect for the next generation nonvolatile memory technologies due to its excellent advantages. Dry etching process of magnetic thin films is one of the important issues for the magnetic devices such as magnetic tunneling junctions (MTJs) based MRAM. CoFeB is a well-known soft ferromagnetic material, of particular interest for magnetic tunnel junctions (MTJs) and other devices based on tunneling magneto-resistance (TMR), such as spin-transfer-torque MRAM. One particular example is the CoFeB - MgO - CoFeB system, which has already been integrated in MRAM. In all of these applications, knowledge of control over the etching properties of CoFeB is crucial. Recently, transferring the pattern by using milling is a commonly used, although the redeposition of back-sputtered etch products on the sidewalls and the low etch rate of this method are main disadvantages. So the other method which has reported about much higher etch rates of >$50{\AA}/s$ for magnetic multi-layer structures using $Cl_2$/Ar plasmas is proposed. However, the chlorinated etch residues on the sidewalls of the etched features tend to severely corrode the magnetic material. Besides avoiding corrosion, during etching facets format the sidewalls of the mask due to physical sputtering of the mask material. Therefore, in this work, magnetic material such as CoFeB was etched in an ICP etching system using the gases which can be expected to form volatile metallo-organic compounds. As the gases, carbon monoxide (CO) and ammonia ($NH_3$) were used as etching gases to form carbonyl volatiles, and the etched features of CoFeB thin films under by Ta masking material were observed with electron microscopy to confirm etched resolution. And the etch conditions such as bias power, gas combination flow, process pressure, and source power were varied to find out and control the properties of magnetic layer during the process.

• 한국대기환경학회지
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• 제32권6호
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• pp.633-641
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• 2016

Two identical Particle Into Liquid Samplers-Total Organic Carbon (PILS-TOC) were operated to measure fine particle Water Soluble Organic Carbon (WSOC) for one week on Feb. in 2016. The dual instrument operations provided validated WSOC concentrations to have a continuous WSOC measurement during the sample analysis period. Both PILS-TOC instruments were operated downstream of an carbon denuder to remove positive adsorption artifacts associated with semi-volatile organic compounds. Comparison of WSOC showed good agreement each other. The linear regression had a coefficient of determination ($r^2$) of 0.92 and a regression slope of 1.01 for the first period. The lower collection efficiency due to lower steam temperature is discussed. In addition, the potential primary source related to WSOC based on the comparison of black carbon (BC) concentrations is explained. The results of good agreement between two PILS-TOC measurements can provide the validation of WSOC cooperations and knowledge regarding the origins of WSOC and their behaviors.

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.255-261
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• 2018

Aglycon protopanaxatriol (APPT) has valuable pharmacological effects such as memory enhancement and tumor inhibition. ${\beta}$-Glycosidase from the hyperthermophilic bacterium Dictyoglomus turgidum (DT-bgl) hydrolyzes the glucose residues linked to APPT, but not other glycoside residues. ${\beta}$-Glycosidase from the hyperthermophilic bacterium Pyrococcus furiosus (PF-bgl) hydrolyzes the outer sugar at C-6 but not the inner glucose at C-6 or the glucose at C-20. Thus, the combined use of DT-bgl and PF-bgl is expected to increase the biotransformation of PPT-type ginsenosides to APPT. We optimized the ratio of PF-bgl to DT-bgl, the concentrations of substrate and enzyme, and the reaction time to increase the biotransformation of ginsenoside Re and PPT-type ginsenosides in Panax ginseng leaf extract to APPT. DT-bgl combined with PF-bgl converted 1.0 mg/ml PPT-type ginsenosides in ginseng leaf extract to 0.58 mg/ml APPT without other ginsenosides, with a molar conversion of 100%. We achieved the complete biotransformation of ginsenoside Re and PPT-type ginsenosides in ginseng leaf extract to APPT by the combined use of two ${\beta}$-glycosidases, suggesting that discarded ginseng leaves can be used as a source of the valuable ginsenoside APPT. To the best of our knowledge, this is the first quantitative production of APPT using ginsenoside Re, and we report the highest concentration and productivity of APPT from ginseng extract to date.

• 한국토양비료학회지
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• 제49권2호
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• pp.144-156
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• 2016

Soil is a dynamic biological system, in which it is difficult to determine the composition of microbial communities. Knowledge of microbial diversity and function in soils are limited because of the taxonomic and methodological limitations associated with studying the organisms. In this review, approaches to measure microbial diversity in soil were discussed. Research on soil microbes can be categorized as structural diversity, functional diversity and genetic diversity studies, and these include cultivation based and cultivation independent methods. Cultivation independent technique to evaluate soil structural diversity include different techniques such as Phospholipid Fatty Acids (PLFA) and Fatty Acid Methyl Ester (FAME) analysis. Carbon source utilization pattern of soil microorganisms by Community Level Physiological Profiling (CLPP), catabolic responses by Substrate Induced Respiration technique (SIR) and soil microbial enzyme activities are discussed. Genetic diversity of soil microorganisms using molecular techniques such as 16S rDNA analysis Denaturing Gradient Gel Electrophoresis (DGGE) / Temperature Gradient Gel Electrophoresis (TGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP), Single Strand Conformation Polymorphism (SSCP), Restriction Fragment Length Polymorphism (RFLP) / Amplified Ribosomal DNA Restriction Analysis (ARDRA) and Ribosomal Intergenic Spacer Analysis (RISA) are also discussed. The chapter ends with a final conclusion on the advantages and disadvantages of different techniques and advances in molecular techniques to study the soil microbial diversity.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.3247-3252
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• 2014

Background: Genetic factors have been shown to play an important role in the development of cancers. However, individual studies may fail to completely demonstrate complicated genetic relationships because of small sample size. Therefore, we performed a meta-analysis to evaluate the association of E-selectin Ser128Arg (S128R) with cancer risk. Materials and Methods: A literature search in PubMed, Embase, Web of Science, Science Direct, SpringerLink, EBSCO, Wanfang, and Chinese National Knowledge Infrastructure databases was carried out to identify studies of the association between E-selectin S128R polymorphism and cancer risk. The odds ratio (OR) with 95% confidence intervals (95%CIs) were used to assess the strength of association. Results: A total of eight studies involving 1,675 cancer cases and 2,285 controls were included in the meta-analysis. In overall populations, S128R polymorphism seemed to be associated with cancer risk (Arg allele vs Ser allele: OR=1.65, 95%CI =1.33-2.04, p<0.01; Arg/Arg+Arg/Ser vs Ser/Ser: OR=1.87, 95%CI =1.48-2.36, p<0.01; Arg/Ser vs Ser/Ser: OR=1.80, 95%CI =1.51-2.14, p<0.01). Similarly, subgroup analysis by ethnicity and source of control also revealed that this polymorphism was related to cancer risk. Conclusions: Our meta-analysis revealed that there was association between the E-selectin S128R polymorphism and the risk of cancer. Further large and well-designed studies are needed to confirm this association.

• 인터넷정보학회논문지
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• 제22권4호
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• pp.65-82
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• 2021

A well-designed website is mandatory for good marketing and proper tourism business. This research considers Nepal as a domain of study and specifically explores welcomenepal.com, the official tourism portal as a reference for the study. The work is based on the study of the existing literature, user-survey, and technical testing of the website using open-source testing tools to identify user perspective, design issues, website architecture and design quality of the tourism website. A population size of 400 respondents, which consist of both domestic and international tourist, are considered for the survey. Data is received from 360 respondents, which is analyzed using statistical tests like Cronbach's alpha, Pearson's correlation, cross-tabulations, bars charts and graphs to draw inferences and consclusion. The software-based test results serve as another important parameter for the evaluation of the current official website. This study brings out core needs of the tourist in terms of expectations from a tourism website and access technical quality of the current portal to provide necessary feedback and suggestions. The government officials, business houses, and web designers can utilize this work as a knowledge base to build tourism websites, which are user-centric. Further, the work is specifically important for Nepal government and tourism officials to identify shortcomings in their current website and make improvements for better design and user adaptability in future.

• The Korean Journal of Pain
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• 제32권4호
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• pp.245-255
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• 2019

Stem cells are attracting attention as a key element in future medicine, satisfying the desire to live a healthier life with the possibility that they can regenerate tissue damaged or degenerated by disease or aging. Stem cells are defined as undifferentiated cells that have the ability to replicate and differentiate themselves into various tissues cells. Stem cells, commonly encountered in clinical or preclinical stages, are largely classified into embryonic, adult, and induced pluripotent stem cells. Recently, stem cell transplantation has been frequently applied to the treatment of pain as an alternative or promising approach for the treatment of severe osteoarthritis, neuropathic pain, and intractable musculoskeletal pain which do not respond to conventional medicine. The main idea of applying stem cells to neuropathic pain is based on the ability of stem cells to release neurotrophic factors, along with providing a cellular source for replacing the injured neural cells, making them ideal candidates for modulating and possibly reversing intractable neuropathic pain. Even though various differentiation capacities of stem cells are reported, there is not enough knowledge and technique to control the differentiation into desired tissues in vivo. Even though the use of stem cells is still in the very early stages of clinical use and raises complicated ethical problems, the future of stem cells therapies is very bright with the help of accumulating evidence and technology.

• 한국치위생학회지
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• 제6권2호
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• pp.115-127
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• 2006

A purpose of this study is degree of recognition and consciousness investigation about a satisfaction duty before admission about a school subject of some academic dental hygiene students. From responses to individual written survey questionnaires answered by 608 students who are studying Dental Hygiene at colleges in Mokpo, Iksan, Gangneung. The following are the results regarding their satisfaction levels with their majors and their interest in working abroad: 1. Regarding the motivating factors to major in Dental Hygiene, most students(51.3%), particularly most freshmen(57.3%), have chosen this major because of more job opportunities than students with other majors. The most common source of information in choosing majors is the Internet(30.8%). 2. Most students do not want to change their majors even if they are provided with the chance to do so(65.5%). They are in general satisfied with their studies. The result shows that the Dental Hygiene majors are positive toward their major. 3. Most students will choose their jobs by their own choices(40.6%), and the most important factor in their choices is the opportunity of self-growth and development(33.1%). The survey results show that the Dental Hygiene students value their own decisions and self-realization. 4. Showed the difference that as a result of having seen a knowledge degree advance a school subject of major in Dental Hygiene by a school year and ash students, an admission motive, relevance of an information acquisition path, all noted. 5. And were able to see the difference that noted in an adviser, work selection bases in case of work selection whether or not there was a dissatisfaction reason about a major and a criminal record.

• 한국환경교육학회지:환경교육
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• 제9권1호
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• pp.58-71
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• 1996

The purpose of this study was to investigate the rural housewives' recognition and practice on environmental preservation. The subjects of this study were 300 rural housewives living in Chung-buk province. Questionaires were distributed to them during a week from August $25^{th}$ to August $31^{th}$ in 1995. Major findings were as follows: 1. The saved water quite well in washing their faces and the dishes compared with urban housewives, but they did not save water so well in using the lavatory. They used synthetic detergent, one of water pollutants, more often than natural soaps in shampooing and laundering. In addition, they did not use a measuring cup. It resulted in the waste of detergent and aggravation of water pollution. 2. Food waste was disposed of properly, but used batteries were not collected separately. A disposable vinyl bag was more commonly used than a reusable shopping basket. The reason for not using a shopping basket was bothering or uncustomary. Since most of them did not know refillable products of goods with environmental mark, they did not use those. Therefore, housewives should be educated in order to prevent soil pollution. 3. The use of spry-type pesticide and hair treatment, one of air pollutants, was wide-spread among them. They hardly recognized and practiced saving of electric power when they used household electric appliances. 4. The major source of environmental knowledge was mass media like TV of radio. Many of them did not know the practical ways to solve the environmental education program. In conclusion, low level of recognition and practice of rural housewives on environmental preservation indicated that a systematic environmental education program should be developed and implemented.

• 한국물환경학회지
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• 제31권6호
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• pp.693-699
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• 2015

It has been known that torrential rainfall events have been occurring worldwide due to climate change. The accelerated soil erosion has caused negative impacts on water quality and ecosystem of receiving waterbodies. Since soil security issues have been arising in various areas of the world, intensive interests have been given to topsoil management in Korea. Thus in this study, Web GIS-based computing system of physical, chemical, and biological topsoil quality indices were developed. In this study, five soil quality maps at national scale and top soil erosion potential were prepared for evaluation of soil quality based on soil erosion potential. For this system, the open source Web GIS engine, OpenGeo, was used as core engine of the system. With this system, decision makers or related personnel in areas of soil erosion Best Management Practices (BMPs) would be able to find the most appropriate soil erosion BMPs based on soil erosion potential and soil quality at the area of interest. The Web GIS system would be efficiently used in decision making processes because of ease-of-use interface and scientific data used in this system. This Web GIS system would be efficiently used because this system could provide scientific knowledge to decision makers or stakeholders. Currently various BMP database are being built to be used as a decision support system in topsoil management and topsoil quality areas.