• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권7호
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• pp.424-429
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• 2004

The 4-probe method with a voltage tap on terminals has been used for the measurement of the critical current of multi-strand high-T$_{c}$ superconducting(HTS) cables. And the critical current of cables is obtained as the measured total current divided by the number of conductor when the terminal voltage exceeds the predetermined criterion of critical current. However, because of the non-uniform current distribution due to the different critical current, shapes, and other characteristics of each conductor, this is not applicable method to the multi-strand HTS cable. To determine the critical current of multi-strand HTS cable, the critical current of each conductor must be measured with different method. h this paper, the current distribution and the critical current of each conductors in multi-strand cable were measured with specially made Pick-up coils and voltage taps. It is presented that the real critical current of multi-strand is smaller than sum of each conductors. The main cause of non-uniform current distribution is the difference between the resistances appeared in each HTS wires.s.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.254-259
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• 2003

The 4-probe method with a voltage tap on terminals has been used for the measurement of the critical current of multi-strand high-Tc superconducting (HTS) cables. And the critical current of cables is obtained as the measured total current divided by the number of conductor when the terminal voltage exceeds the predetermined criterion of critical current. However, because of the non-uniform current distribution due to the different critical current, shapes, and other characteristics of each conductor this is not applicable method to the multi-strand HTS cable. To determine the critical current of multi-strand HTS cable the critical current of each conductor must be measured with different method. In this paper, the current distribution and the critical current of each conductor in multi-strand cable were measured with specially made pick-up coils and voltage taps. It is presented that the real critical current of multi-strand is smaller than sum of each conductors. The main cause of non-uniform current distribution is the different resistances appeared in each HTS wires.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.2004-2007
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• 2006

An efficient method for the in vitro reassembly of homologous DNA sequences is presented. The proposed method involves obtaining single strands of homologous genes and hybridizing them to obtain partially hybridized heteroduplex DNA; cleaving the single-stranded regions of the heteroduplex DNA using S1 nuclease to generate double-strand DNA fragments; denaturing the double-strand DNA fragments to generate single-strand DNA fragments; conducting a series of polymerase chain reactions (PCR) using the single-strand DNA fragments as internal primers and a mixture of homologous DNA as templates to obtain elongated reassembled DNA; and finally, amplifying the reassembled DNA by a PCR using terminal primers. As a result, DNA reassembly could be achieved between homologous genes with a sequence similarity as low as 78%.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 1994년도 제3회 학술강연회논문집
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• pp.39-45
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• 1994

Combustion characteristics of the solid composite propellants were studied from burning rate, ignition and steady combustion processes, and structure of the extinguished surfaces. Optical Vacuum Strand Burner (OVSB) system was desisted and configured to study those. Burning rates of the propellants were measured by OVSB at low pressure range by developed ten method. video camera(30 frames/s) was used to take potographs of the phenomena of ignition and combustion of propellant within the test cell of the OVSB. Burning surfaces of the propellants that were extinguished by rapid depressurization method were analyzed with Scanning Electron Microscope. (SEM).

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.339-343
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• 2016

Background: Evaluation of deoxyribonucleic acid (DNA)-strand break is important to elucidate the biological effect of ionizing radiations. The conventional methods for DNA-strand break evaluation have been achieved by Agarose gel electrophoresis and others using an electrical property of DNAs. Such kinds of DNA-strand break evaluation systems can estimate DNA-strand break, according to a molecular weight of DNAs. However, the conventional method needs pretreatment of the sample and a relatively long period for analysis. They do not have enough sensitivity to detect the strand break products in the low-dose region. Materials and Methods: The sample is water, methanol and plasmid DNA solution. The plasmid DNA pUC118 was multiplied by using Escherichia coli JM109 competent cells. The resonance frequency and Q-value were measured by means of microwave dielectric absorption spectroscopy. When a sample is located at a center of the electric field, resonance curve of the frequency that existed as a standing wave is disturbed. As a result, the perturbation effect to perform a resonance with different frequency is adopted. Results and Discussion: The resonance frequency shifted to higher frequency with an increase in a concentration of methanol as the model of the biological material, and the Q-value decreased. The absorption peak in microwave power spectrum of the double-strand break plasmid DNA shifted from the non-damaged plasmid DNA. Moreover, the sharpness of absorption peak changed resulting in change in Q-value. We confirmed that a resonance frequency shifted to higher frequency with an increase in concentration of the plasmid DNA. Conclusion: We developed a new technique for an evaluation of DNA damage. In this paper, we report the evaluation method of DNA damage using microwave dielectric absorption spectroscopy.

• 한국추진공학회지
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• 제17권2호
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• pp.39-45
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• 2013

추진제를 고에너지 금속 분말 연소시스템에 점화원으로 적용을 위한 기초 연구로서 strand burner를 이용하여 HTPB/AP/Al, HTPE/AP/Al 추진제의 연소특성을 고찰하였다. 실험은 아르곤을 사용하여 ~300 psia 까지 가압하였으며, 2개의 석영창을 이용하여 가시화하였다. 추진제 점화를 위해서 10 W의 $CO_2$ 레이저를 사용하였으며, 연소 속도 측정은 초고속 카메라를 활용한 프레임 분석 기법 및 광다이오드를 이용한 연소시간 분석 기법을 적용하였다. 스펙트로메터를 이용하여 300 nm ~ 800 nm, 1500 nm ~ 5000 nm 의 방출 스펙트럼을 분석하여 추진제 연소반응 시 발생하는 화학종을 확인하였다.

• 한국전산구조공학회논문집
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• 제21권3호
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• pp.287-294
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• 2008

이 연구에서는 교량 상부구조물의 보수 보강에 많이 사용되는 7연 강연선의 공용중 긴장력 관리를 위한 새로운 방법은 제안하였다. 제안된 스마트 강연선은 기존 강연선의 중앙 킹와이어를 강제튜브로 대체하고, 강제튜브의 내부에 FBG 광섬유센서를 설치하여 강연선의 변형률을 측정할 수 있도록 하였다. 내장된 센서를 통하여 이 스마트 강연선의 변형률을 쉽게 측정할 수 있으므로, 공용중 강연선의 긴장력을 모니터링할 수 있다. 본 연구에서 제안된 장력 모니터링 방법의 효용성을 증명하기 위하여 FBG센서 2개가 내장된 길이 7.0m인 스마트 강연선을 제작하고, 이를 길이 6.4m, 높이 0.6m인 RC T형 모형거더에 외장형 텐던으로 적용하였다. 그리고 이 시험거더에 대한 재하-제하시험을 실시하고 로드셀에서 계측된 긴장력과 스마트 강연선을 이용하여 예측한 긴장력을 비교하였다. 비교 결과, 제안된 스마트 강연선은 긴장력이 작용된 강연선의 장력을 정확하게 모니터링 하는데 유용함을 확인할 수 있었다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.133-138
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• 2008

This study proposes a novel method for in-service evaluation of force in an external prestressing 7-wire tendon which is employed for retrofitting bridge superstructure. For this propose, a smart strand 7.0m long whose king wire is replaced by a steel tube and the FBG sensor, is developed. Performance of the strand is demonstrated through loading-unloading tests for a RC T-shaped beam 6.4m long. Finally, a couple of test results are presented to discuss effect of temperature change in the FBG sensor.

• 대한기계학회논문집A
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• 제25권1호
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• pp.127-134
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• 2001

Wire ropes are widely used in cable car, suspension bridge and elevator, etc. and composed of single or multi-layer strands. It is difficult to find out the characteristics of a strand or wire rope because of complicated geometry and contact condition. In this study, the axial stiffness is evaluated using finite element method and reliable finite element analysis model is presented, taking into consideration the convergence on the length. The axial stiffness predictive equation of a strand is developed using analysis of variance, which can be applicable for characterizing the relationship between load and displacement when the strand configuration is determined.

• Archives of Pharmacal Research
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• 제26권2호
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• pp.147-150
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• 2003

To find anticancer agents from higher plants, DNA strand-scission assay method was employed for bioassay-guided fractionation as well as for screening the crude extracts. During the screening, an ethyl acetate extracts of the heartwood of Caesalpinia sappan L. (Leguminosae) exhibited potent DNA strand-scission activity. Therefore, the ethyl acetate extracts of the dried heartwood of C. sappan was subjected to the bioassay-guided fractionation, which led to the isolation of a known compound, brazilin (1) as the active constituent. In addition, caesalpine J (2) was also isolated as an inactive constituent.