• Title, Summary, Keyword: Strand method

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Non-uniform Current Distribution of Multi-Strand HTS Cable (다중-스트랜드 고온초전도케이블의 불균등 전류분포)

  • 배준한;배덕권;심기덕;조전욱;고태국
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.7
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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.

Non-Uniform Current Distribution of Multi-Strand HTS Cable (Multi-Strand HTS 케이블에서의 전류 불균일 분포)

  • Bae, Joon-Han;Bae, Duck-Kweon;Cho, Jeon-Wook;Sim, Ki-Deok;Kim, Hae-Jong;Seong, Ki-Chul;Ko, Tae-Kuk
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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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.

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Effective Family Shuffling Method Using Complementary DNA Fragments Produced by S1 Nuclease

  • Hong, Soon-Gyu
    • Journal of Microbiology and Biotechnology
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    • v.16 no.12
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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%.

A Study on the Burning Characteristics of Composite Propellants at Low Pressure using Vacuum Strand Burner (Vacuum Strand Burner를 이용한 혼합형 추진제의 저압 연소특성 연구)

  • 김인철;유지창;박영규;이태호
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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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).

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An Experimental Study of Laser-induced Ignition of Solid Propellant with Strand Burner (레이저 점화에 의한 고체추진제 Strand Burner 실험)

  • Lee, Sanghyup;Ko, Taeho;Yang, Heesung;Yoon, Woongsup
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.2
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    • pp.39-45
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    • 2013
  • Basically, in order to apply solid propellant as ignition source to high energy metal particle combustion system, we analyzed combustion characteristics of the HTPB/AP/Al, HTPE/AP/Al propellants by using a strand burner. The propellants were tested in a high-pressure windowed strand burner, which was pressurized up to 300 psia with pure argon gas. Strand burner was visualized with two quartz windows and ignition was accomplished by a 10 W $CO_2$ laser. The burning rate of propellant was measured with high-speed camera method for frame analysis and photodiode method for combustion time analysis. Emission spectrum was measured with spectrometer at 300 nm ~ 800 nm and 1500 nm ~ 5000 nm and then we analyzed species during propellant combustion.

Evaluation of DNA Damage Using Microwave Dielectric Absorption Spectroscopy

  • Hirayama, Makoto;Matuo, Youichirou;Sunagawa, Takeyoshi;Izumi, Yoshinobu
    • Journal of Radiation Protection and Research
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    • v.41 no.4
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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.

A Study on the Axial Stiffness Prediction of Stand Using Analysis of Variance (분산분석을 이용한 스트랜드의 축강성 예측에 관한 연구)

  • Park, Yong-Dae;Yang, Won-Ho;Heo, Seong-Pil;Seong, Gi-Deuk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.1
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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.

FE Analysis of Forged Parts of Suspension Bridge : cases of Strand Shoe and Hanger Socket (입체요소를 이용한 현수교 주단강품의 유한요소해석 : 스트랜드슈와 행어소켓)

  • 최창근;이태열;노혁천;김재철
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.149-156
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    • 1998
  • In suspension bridges, the axial farces in the wires are transferred by side pressure on the semicircular face, and further from the strand shoe through rods to a base plate fixed to the massive concrete part of the anchor block. For prefabricated strands the most common way of anchoring is by socketing the ends of the strands. In this study, strand shoe and hanger socket are analyzed far various load conditions using Finite Element Method. The finite element models are built using MSC/PATRAN and analysis is carried out using MSC/NASTRAN. Results are again completely processed using MSC/PATRAN. From the results of the analysis, trends of deformation and stress distribution are reviewed and important factors to consider in the design of strand shoe and hanger socket are discussed.

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A Methodology for Monitoring Prestressed Force of Bridges Using OFS-embedded Strand (광섬유센서가 내장된 강연선을 이용한 교량의 장력 모니터링 방법)

  • Kim, Hyoun-Wo;Kim, Jae-Min;Kim, Jin-Won;Kim, Young-Sang;Yun, Chung-Bang
    • Proceedings of the Computational Structural Engineering Institute Conference
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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.

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A DNA Strand-Nicking Principle of a Higher Plant, Caesalpinia sappan

  • Mar, Woongchon;Lee, Hyun-Tai;Je, Kang-Hoon;Choi, Hye-Young;Seo, Eun-Kyoung
    • Archives of Pharmacal Research
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    • v.26 no.2
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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.