• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.862-867
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• 2013

Torsional interaction between electrical network phenomena and turbine-generator shaft cause torsional stress on turbine-generator shaft and torsional fatigue fracture on vulnerable component, but the prediction of the torsional stress is difficult because the torsional stress is occurred instantly and randomly. Therefore continuous monitoring of the torsional stress on turbine-generator shaft is necessary to predict the torsional fatigue, but installing the sensors on the surface of the shaft directly to monitor the stress is impossible practically. In this study torsional vibration was measured using magnetic sensor at a point of turbine-generator rotor kit, the torsional stress of whole train of rotor kit was calculated using rotor kit's stress model and the calculated results were verified in comparison with the measured results using strain gauge at several point of turbine-generator rotor kit. It is expected that these experiment results will be used effectively to calculate the torsional stress of whole train of turbine-generator rotor in power plants.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.40.4-40.4
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• 2020

Kyung Hee university invented the Transformable Reflective Telescope (TRT) for optical experiment and education. The TRT kit can transform into three optical configurations from Newtonian to Cassegrain to Gregorian by exchanging the secondary mirror. We designed the Ebert-Fastie spectrograph as an extension of the TRT kit. The primary mirror of the TRT kit serves as both collimator and camera lens, and the reflective grating as the dispersing element is placed along the optical axis of the primary mirror. We designed and fabricated the grating holder and the source units using 3D printer. Baffle was also fabricated to suppress the stray light, which was reduced by 83%. The spectrograph can observe the optical wavelength range (4000Å~7000Å). Measured resolving power (R=λ/Δλ) was ~700 with slit width of 0.18mm. The spectrograph is optimized for f/24, and the spectral pixel scale is 0.49Å/pixel with Canon 550D detector. We present the sample spectra of discharged Ne, Ar and Kr gases. The flexible setting and high performance make this spectrograph a useful tool for education and experiment.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.38.1-38.1
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• 2021

본 발표에서는 Transformable Reflective Telescope(TRT kit)의 새로운 버전을 소개한다. TRT kit는 기본형인 뉴턴식 반사망원경에서 부경 교체를 통해 카세그레인식, 그레고리식으로 간단하게 변형 할 수 있는 광학 실험장치이다. 본 장치는 주로 망원경 교육이나 광학계 개발에 필요한 실험에 활용된다. 모듈화 설계를 통해서 여러 종류의 광학계를 쉽게 탈착하여 다양한 실험을 할 수 있다. 광기계부는 정밀하게 제작된 알루미늄 프로파일과 Isogrid구조를 채택하여 경량화 구조로 설계되었다. 이러한 경량부품들을 통해 이전 버전보다 50~70%의 중량 감소율을 달성하였다. 유한요소해석 결과 경량화된 뉴턴식 TRT kit는 이전 버전과 비교해서 자체 하중에 의한 최대 구조 변형이 0.11mm에서 0.023mm로 감소하였다. 부경 지지대 설계에는 자체 하중으로 인한 변형을 최소화하기 위해 트러스 (Truss) 구조가 도입되었다. 부경부의 자체 하중으로 인한 변형은 기존의 80㎛에서 21㎛로 감소하였다. 또한, 십자 레이저 정렬 장치가 추가되어 뉴턴식과 카세그레인식에서 공차 1.5' 이내로 광학계 정렬이 가능하다.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.901-910
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• 2023

In universities, programming language-based thinking and software education for non-majors are being implemented to cultivate creative and convergent talent capable of leading the digital convergence era in line with the Fourth Industrial Revolution. However, learners face difficulties in acquiring the unfamiliar syntax and programming languages. The purpose of this study is to propose a software education model to alleviate the challenges faced by non-major students during the learning process. By introducing algorithm techniques and diagram techniques based on programming language thinking and using the EZMKER kit as an instructional model, this study aims to overcome the lack of learning about programming languages and syntax. Consequently, a structured software education model has been designed and implemented as a top-down system learning model.

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.401-411
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• 2003

One of the most important characteristics in the seventh educational course is an enforcement of differentiated level curriculum. Therefore, development of various different level educational subjects is needed. A new chromatographic experimental kit which is helpful for middle school students to understand chromatographic principles is needed to correct some mistakes of chromatographic part within the 6th educational course's middle school textbook. In this research, a new thin layer chromatography(TLC) experimental kit for middle school students are developed by using acid-base indicator as samples and ethyl alcohol, ethylacetate, hexane as eluents. The kit is applied to two kinds of middle school student groups(general group & genius group) and two kinds of teacher groups(science teacher & non-science teacher) and an efficacy of the new chromatographic kits are evaluated through making up some questions.

• Journal of Environmental Health Sciences
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• v.34 no.5
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• pp.369-373
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• 2008

The indoor environment is an important source of exposure to various aeroallergens and pathogenic microorganism. It has been shown that exposure to aeroallergens enhances the risk of indoor inhabitants developing asthma. Since the skin prick test, a typical clinical method for identification of subjects positive to allergens, can rarely cause fatal or non-fatal reactions in susceptible persons, an in vitro assay such as ELISA using serum has been considered for testing positivity against various allergens. We evaluated the validity of a serum ELISA kit for screening positive subjects to major aeroallergens including Dermatophagoides farinae, Dermatophagoides pteronyssinus, cockroach, Alternaria, Cladosporium, Aspergillus, Penicillium, dog hair, cat fur, mugwort, and ragweed. The ELISA results were compared with the skin prick test results, and sensitivity, specificity, and overall accuracy were calculated to each allergen. Higher sensitivities were obtained from D. farinae, (77.8%) and D. pteronyssinus (69.2%), but sensitivities to Aspergillus, Penicillium, dog hair, cat fur, and ragweed were very low down to 0%. Specificity ranged from 88.7% (cat fur) to 100% (mugwort and ragweed). Overall the accuracy of the serum ELISA kit was relatively high, in that the lowest was 85.1% for cat fur and the highest was 98.6% for Alternaria, Cladosporium, and ragweed. Considering specificity and overall accuracy for the serum ELISA kit, it may be considered reliable. However, when the kit is used for screening purpose, positivity to aeroallergens should be carefully determined since sensitivity for the kit is low.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.683-691
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• 2014

Significance of SAR(Synthetic Aperture Radar) satellite regadless of weather have grown for Earth observation. According to the cost-effective trend in satellite development, SAR antenna is actively studied. It's a competitive candidate to use deployable SAR antenna out of CFRP. In this study, variables for an antenna configuration model was researched and evaluated. The design of the antenna was structurally analyzed by FEM(Finite Element Model). Tool-kit was developed for modifying the SAR antenna model easily in accordance with system requirement change. In the tool-kit, antenna configuration design and error analysis of the antenna surface could be achieved. And compatibility of tool-kit results to CST, a RF analysis program, was confirmed.

• Journal of Animal Science and Technology
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• v.54 no.6
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• pp.411-418
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• 2012

KIT gene is the major causative gene for coat color variation in diverse animal species. This gene regulates melanocyte migration from the neural crest to target tissues and the mutation of this gene can affect dominant white phenotypes in animals. Because this gene has a major influence for the coat color variation, single nucleotide polymorphisms (SNPs) in 14 Korean cattle (Hanwoo) and 5 Holstein individuals were investigated. The Hanwoo DNA samples included three different colored (5 Black, 5 Yellow and 4 Stripe) animals. Total 126 polymorphisms have been identified and 23 of them are located in the exon region. Also, 5 bp (TTCTC) and 3 bp (TCT) intronic indels in intron 3 and intron 5, respectively, were identified. Out of 23 exonic polymorphisms, 15 SNPs are the missense mutations and the rest of the SNPs are silence mutations. The neighbor-joining phylogenetic tree was constructed for the different colored animals using the obtained KIT gene sequences. Holstein breed showed a clear breed-specific cluster in the phylogenetic tree which is differed from Hanwoo. Also, three colored Hanwoo animals were not discriminated among the breeds. The KIT gene polymorphisms identified in this study will possibly give some solutions for the color variations in cattle with further verifications.

• Journal of Engineering Education Research
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• v.6 no.2
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• pp.5-14
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• 2003

In this paper, we developed an efficient virtual experiment kit with creative and interactive multimedia contents, which can be used to enhance the quality of education in the area of digital logic circuits. Since our virtual experiment kit is implemented to describe the on-campus laboratory, the learners can obtain similar experimental data through it. Also, our web-based virtual experiment kit is designed to enhance the efficiency of both the learners and the educators. The learners will be able to achieve high learning standard and the educators save time and labor. The virtual experiment is performed according to the following procedure: (1) Circuit Composition on the Bread Board (2) Applying Input Voltage (3) Output Measurements (4) Checkout of Experiment Results. Furthermore, the circuit composition on the bread board and its corresponding online schematic diagram are displayed together on the virtual experiment kit for the learner's convenience. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing learning efficiencies as well as faculty productivity.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.335-340
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• 2016

This study was conducted to find out the most suitable DNA isolation methods for PCR detection of foodborne pathogens. Four DNA isolation methods including Universal Genomic DNA Extraction Kit (TaKaRa), PrepMan Ultra (Applied Biosystems), boiling method and alkaline lysis method (w/PEG) were tested and compared. The Universal Genomic DNA Extraction kit (TaKaRa) was considered as the more efficient isolation method for Escherichia coli O157:H7 and Staphylococcus aureus in lettuce, fish and beef. Meanwhile to detect the foodborne pathogens directly from foods without enrichment, the four different buffers such as double-distilled water, saline, glycine-saline, glycine-saline with Tween-20 and beef extract were also evaluated. As a result, saline was more suitable buffer for E. coli O157:H7. And double-distilled water was more suitable buffer than saline for S. aureus, respectively