• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.21-31
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• 1977

The study has been carried out to compare the pathogenicity, physiological characteristics and genetic reliability between rough colony type strain and smooth colony type strains of Pseudomonas mori (Boyer et Lambert) Stevens which were isolated from diseased plant parts in 5 different areas throughout country. The results are summarized as follow. 1. The rough colony type strain showed more agressive reactions to tested host plant varieties than smooth colony type strains though there was no differences in the appearence of lesion types caused by both strains. 2. Both colony types were differentiated morphologically in that the rough colony type strain was having more than 200r long filamentous body without flagella where as the smooth colony type strains have short rods with one or several polar flagella. 3. The colony of smooth type strains was circular, entire, smooth and opaque, while the rough type strain shelved endulated, irregular margin, rough and wrinkled colony on nutrient agar media. 4. There were no differences between both colony types in the physiological and serological test. 5. Both of smooth and rough colony type strains showed genetic reliability through more than 100 succeeding cultures on the media, and were stable to various chemicals such as 1 to 3 percent of NaCl, 5 kinds of organic acid and 4 kinds of antibiotics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.482-494
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• 2016

This study examines the longitudinal trends regarding awareness of informatization, Information Technology (IT) use, and attitudes towards IT among older adults aged 60 or over. Surveys were conducted in 2004 and 2014 at senior welfare centers in Seoul, Korea. The trends between 2004 and 2014 showed that the rate of Internet use increased among older adults who lived alone, were aged 70 or over, had middle education level, had low income, or were unemployed. Older adults had positive attitudes towards IT, and users were more positive than non-users. The levels of IT use were low among users, and their reasons for IT use were for psychological, emotional, and practical purposes. For non-users of IT, their passive tendencies toward IT use and informatization were amplified. As such, the state of IT use and attitudes toward it among older adults in Seoul were longitudinally different, and the differences in awareness and ability between users and non-users tended to increase.

• Journal of The Korean Association For Science Education
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• v.38 no.3
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• pp.331-341
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• 2018

The purpose of this study is to explore relationships among the structural elements of Science Classroom as Community of Practice (SCaCoP). For this, we investigated the case of small-group activities in practical work of elementary school science in a qualitative way based on the five structural elements of SCaCoP, such as responsibility for learning, common interest, open participation, mutual relationship, and practice. We observed and interviewed five small-groups during five lessons with video- and audio- recording to collect data. The results of analysis are as follows. First, 'mutual relationship' was a necessary-condition for 'open participation.' We also found that 'common interest' has two dimensions related to their interest and related to learning topic. The former interacted with 'open participation,' and the latter was influenced by 'responsibility for learning. Lastly, 'practice' enhanced the features of other elements with dynamic relationships. Based on these results, we suggested the relationships among the structural elements of SCaCoP and discussed implications related to the perspective that regards learning as participation.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.764-771
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• 1994

Electrochemical synthesis of conductive polypyrrole films was carried out in nucleophilic solvent containing p-toluenesulfonic acid or bezensulfonic acid as supporting electrolyte and dopant. Also characteristics of degradation and improvement of mechanical properties were studied. The conductivity, tensile strength and elongation of the films obtained in dimethyformamide/p-toluenesulfonic acid had the highest value of 10-40S/cm, $25N/mm^2$ and 10%, respectively. The optimum condition of electrochemical synthesis was $2mA/cm^2$ for constant current method and 0.9V for constant potential method containing 0.5M pyrrole and 0.5M p-TSA. The obtained films showed good stability in air and electrode characteristics of secondary battery by reversibility in doping and undoping. The degradation process was 1st order reaction at various temeprature. The activation energy and rate constant of degradation reaction were $1.01JK^{-1}mol^{-1}$ and $3.1{\times}10^{-7}min^{-1}$ respectively at $25^{\circ}C$. For the improvement of mechanical properties, composition of polypyrrole films with various host polymer were investigated and increase of tensile strength and elongation was confirmed.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.40-48
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• 1999

This study was designed to examine the specificities of the designed primers for F. nucleatum and F. necrophorum and to compare the PCR results using clinical samples with those of the anaerobic culture method. F. nucleatum and F. necrophorum spp. are frequently isolated in infected root canals, and they are related to periapical diseases. F. nucleatum(VPI 10197) and F. necrophorum(ATCC 25286) were used as references for PCR reaction, and thirty five teeth with one canal and periapical lesion were used. The samples were cultured anaerobically and identified using Rapid ID 32A(BioMerieux Vitek, Inc., France) as biochemical battery. In the GenBank database, species-specific PCR primers(nuc1/nuc2 primers for F. nucleatum and nec1/nec2 primers for F. necrophorum) were designed from the 16S ribosomal DNA(rDNA) sequences of F. nucleatum(accession number M58683) and F. necrophorum(accession number AF044948). PCR procedures of F. nucleatum(VPI 10197) and F. necrophorum (ATCC 25286) were simulated on a computer software. Amplify(v.1.2${\beta}$ for Macintosh). 820 bps and 817 bps of nucleotides were expected, respectively. Using extracted DNAs with QiaAmp tissue kit(Qiagen co., Germany), PCR was done. The results were as follows : 1. The nuc1/nuc2 primers produced an amplicon of 820 bps and the nec1/nec2 primers produced an amplicon of 817 bps. 2. The nuc1/nuc2 primers and the nec1/nec2 primers were specific and did not react with species other than the designated ones(i.e. nuc1/nuc2 primers did not produce amplicons for F. necrophorum, and vice versa.). And the PCR products of Porphyromonas endodontalis(ATCC 35406), Porphyromonas gingivalis(ATCC 33277), Prevotella intermedia(ATCC 25611), and Prevotella nigrescens(ATCC 33563), frequently isolated in infected root canals and periapical lesions, were not amplified by the primers specific for Fusobacterium nucleatum and Fusobacterium necrophorum. 3. This method utilizing PCR could detect F. nucleatum and F. necrophorum in clinical samples, while anaerobic culture method could detect neither.

• Journal of Environmental Health Sciences
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• v.44 no.5
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• pp.480-490
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• 2018

Objective: This study aimed to report the level of extremely low frequency-magnetic field (ELF-MF) emitted by portable hand-held fans (HHF) and to discuss the methodologies for determining the health risk of ELF-MF for HHF products. Method: ELF-MF was monitored at eight locations by distances in the vicinity of HHFs. A total of 13 HHF brands on the market were randomly selected. A portable ELF-MF monitor MDEX II was used to measure the ELF-MF level in the range of 40-800 Hz with a resolution of $0.01{\mu}T$. This study also examined the frequency results of a total of 45 HHF products investigated by the Korean Ministry of Science and ICT (KMSICT). Results: ELF-MF higher than $0.3{\mu}T$ was found to be emitted at a distance of less than 20 cm from 12 HHF. ELF-MF emitted from four products was found to exceed the reference level ($83.3{\mu}T$ based on 60 Hz) recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). KMSIT reported that the principle frequency emitted from the HHFs ranged from 54 Hz to 284 kHz, without the level of LEF-MF. Unscientifically, the KMSICT used the reference level by ICNIRP as the chronic level and concluded that all HHFs are safe with a basis of 1.2-36.0% less than the reference level. Conclusion: The HHF emitted much higher levels of ELF-MF than $0.3-0.4{\mu}T$, which is regarded as the reference level for childhood leukemia. The risk of HHF should be examined in terms of whether they can be used by the general public, including children and pregnant woman.

• Journal of Engineering Education Research
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• v.12 no.4
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• pp.84-92
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• 2009

The purpose of this study was to investigate the level of self-regulated learning ability for engineering students. Self-regulated learning theory has been studied as the theoretical background and assessment framework explaining life-long ability. A survey was conducted to engineering students from an engineering-centered university, located in Seoul. The research findings were as follows. First, each mean of cognitive regulation, motivation regulation, and behavior regulation was 3.041, 3.051, and 2.996 respectively, indicating that the scores were not high. Second, there was no significant difference in the mean score of self-regulated learning ability between female and male students. Third, students in ABEEK accredited program scored meaningfully higher than students in non-accredited program on only 3 sub-components of organization strategy, metacognition, and task value. Fourth, senior students scored meaningfully higher than 1st year students on only 3 sub-components of metacognition, intrinsic motivation, learning environment management. The results revealed that instructional interventions should be provided for engineering students to develop self-regulated learning ability.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.700-704
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• 2009

A simulation study on SCR(steam carbon dioxide reforming) in gas-to-liquid(natural gas to Fischer-Tropsch synthetic fuel) process was carried out in order to find optimum reaction conditions for SCR experiment. Optimum operating conditions for SCR process were determined by changing reaction variables such as temperature and $CH_4/steam/CO_2$ feed ratio. Simulation was carried out by Aspen Plus. During the simulation, overall process was assumed to proceed under steady-state conditions. It was also assumed that physical properties of reaction medium were governed by RKS(Redlich-Kwong-Soave) equation. Optimum simulation variables such as temperature and feed ratio were determined by considering $H_2/CO$ ratio for FTS(Fischer-Tropsch synthesis), $CH_4$ conversion, and $CO_2$ conversion. Simulation results showed that optimum reaction temperature and $CH_4/steam/CO_2$ feed ratio in SCR process were $850^{\circ}C$ and 1.0/1.6/0.7, respectively. Under optimum temperature of $850^{\circ}C$, $CH_4$ conversion and $CO_2$ conversion were found to be 99% and 49%, respectively.

• Journal of Korean Society of Forest Science
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• v.109 no.1
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• pp.72-80
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• 2020

Two strategies for calculating economic feasibility are the machine rate and cash-flow methods. This study used the cash-flow method to evaluate the economic feasibility of the HAM300 yarding operation for extracting tree length logs in Larix kaempferi forest stands. In financial analysis based on 7-year cash-flow, the net present value and pay-back period method were used. We analyzed two scenarios: operating opportunities (50, 100, 150, and 200 days per year) and productivity change yield (7.5 and 10.5 ㎥/scheduled machine hour: SMH). The analysis indicated that high rates of return on extraction activity investment can be achieved when machines are used for >150 days per year. In addition, improved productivity (10.5 ㎥/SMH) increased financial feasibility compared to current productivity (7.5 ㎥/SMH) when machines were operated for 100 days per year. These results suggest that the appropriateness of HAM300 harvesting depends on the number of annual operating days and productivity.

• Journal of agricultural medicine and community health
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• v.45 no.1
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• pp.13-40
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• 2020

Objectives: The purpose of this manuscript was to propose the policy and perspectives of prevention and management for hypertension and diabetes in Korea. Methods: Authors reviewed the chronic disease prevention and management projects and models were executed in Korea until now, and analyzed and evaluated their performances. Results: In the circumstances of Korea, the following several requisites should be improved ; Specific Korean strategy for development and pursuing of national level policy agenda for chronic disease management must be established. There are a need to establish several means of supplementing the weaknesses of the current chronic disease management policies and programs. Firstly, development and distribution of contents of guidelines on the systematic project execution regime (regarding systematization of local community, subjects and contents of the projects) with guarantee for the quality of chronic disease prevention and management are necessary. Secondly, there is a need for development of information system that can lead the chronic disease management programs currently being implemented. Thirdly, there is urgent need to develop resources such as cultivation of manpower and facilities for provision of education and consultation for the patients and holders of risk factors of chronic disease. Fourthly, there is a need for means of securing management system and financial resources for operation of policies and programs. Conclusions: The results can be able to use as a road map, models, and direction and strategies of policies for chronic disease prevention and management of Korea.