• Title/Summary/Keyword: current decay

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Spent fuel characterization analysis using various nuclear data libraries

  • Calic, Dusan;Kromar, Marjan
    • Nuclear Engineering and Technology
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    • v.54 no.9
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    • pp.3260-3271
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    • 2022
  • Experience shows that the solution to waste management in any national programme is lengthy and burdened with uncertainties. There are several uncertainties that contribute to the costs associated with spent fuel management. In this work, we have analysed the impact of the current nuclear data on the isotopic composition of the spent fuel and consequently their influence on the main spent fuel observables such as decay heat, activity, neutron multiplication factor, and neutron and photon source terms. Nuclear libraries based on the most general nuclear data ENDF/B-VII.0, ENDF/B-VII.1, ENDF/B-VIII.0 and JEFF-3.3 are considered. A typical NPP Krško fuel assembly is analysed using the Monte Carlo code Serpent 2. The analysis considers burnup of up to 60 GWd/tU and cooling times of up to 100 years. The comparison of results showed significant differences, which should be taken into account when selecting the library and evaluating the uncertainty in determining the characteristics of the spent fuel.

Antisense Oligonucleotide Therapeutics for Cystic Fibrosis: Recent Developments and Perspectives

  • Young Jin Kim;Adrian R. Krainer
    • Molecules and Cells
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    • v.46 no.1
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    • pp.10-20
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    • 2023
  • Antisense oligonucleotide (ASO) technology has become an attractive therapeutic modality for various diseases, including Mendelian disorders. ASOs can modulate the expression of a target gene by promoting mRNA degradation or changing pre-mRNA splicing, nonsense-mediated mRNA decay, or translation. Advances in medicinal chemistry and a deeper understanding of post-transcriptional mechanisms have led to the approval of several ASO drugs for diseases that had long lacked therapeutic options. For instance, an ASO drug called nusinersen became the first approved drug for spinal muscular atrophy, improving survival and the overall disease course. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF). Although Trikafta and other CFTR-modulation therapies benefit most CF patients, there is a significant unmet therapeutic need for a subset of CF patients. In this review, we introduce ASO therapies and their mechanisms of action, describe the opportunities and challenges for ASO therapeutics for CF, and discuss the current state and prospects of ASO therapies for CF.

Fabrication of Prototype Persistent Current Switch System Using by BSCCO-2223 Tape (BSCCO-2223 선재를 이용한 Prototype 영구전류스위치 시스템의 제작)

  • 강형구;김정호;이응로;안민철;김호민;윤용수;오상수;주진호;고태국
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2001.02a
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    • pp.72-75
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    • 2001
  • The persistent current mode operation of HTS coils is one of the key technologies required for very high-field MRI magnets composed of LTS and HTS coils. But to date, the fabrication of persistent current mode system using HTS is not investigated well. In this paper, we fabricated the magnet and PCS using by BSCCO-2223 tape and jointed them with solder. The current decay behavior of the circuit was measured in liquid nitrogen by monitoring the magnetic field in the centre of magnet with a Hall sensor. To enhance the characteristic of persistent current mode system, superconducting joint method should be investigated.

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A Study on the Green Emission Characteristics of Organic Device Produced by LB Method (LB법에 의해 제작된 유기소자의 녹색 발광특성에 관한 연구)

  • Chon, Dong-Kyu;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.506-509
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    • 2002
  • In this paper. we give pressure stimulation into organic ultra thin films and detected the induced displacement current proper ties, and then manufacture a device under the accumulation condition. In processing of a device manufacture. And electroluminescence(EL) from conjugated polymers has recently received great attention because polymer light-emitting diodes(LEDs) clealy have potential for applications such as large-area displays. The operation of polymer LEDs is based on double injection of electrons and holes from the elextrodes. followed by formation of excitons whose radiative decay results in light emission at wavelength characteristic to the material. In this paper, we fabricated the single layer EL device using $Alq_3$ as emitting material. According as turn on voltage could know about 5.5V in voltage-current characteristics and voltage rise, current could see that increase as non-linear, Current and ruminance can see that express similar relativity in voltage, and could know that ruminance is expressing current relativity.

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Development of Radiation Free Soft X-Ray Ionizer with Ion Control (완전차폐 및 이온조절형 연X선식 정전기제거장치의 개발)

  • Jeong, Phil Hoon;Lee, Dong Hoon
    • Journal of the Korean Society of Safety
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    • v.31 no.5
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    • pp.22-27
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    • 2016
  • The Electrostatic Charge Prevention Technology is a core factor that highly influences the yield of Ultra High Resolution Flat Panel Display and high-integrated semiconductor manufacturing processes. The corona or x-ray ionizations are commonly used in order to eliminate static charges during manufacturing processes. To develop such a revolutionary x-ray ionizer that is free of x-ray radiation and has function to control the volume of ion formation simultaneously is a goal of this research and it absolutely overcomes the current risks of x-ray ionization. Under the International Commission on Radiological Protection, it must have a leakage radiation level that should be lower than a recommended level that is $1{\mu}Sv/hour$. In this research, the new generation of x-ray ionizer can easily control both the volume of ion formation and the leakage radiation level at the same time. In the research, the test constraints were set and the descriptions are as below; First, In order not to leak x-ray radiation while testing, the shielding box was fully installed around the test equipment area. Second, Implement the metallic Ring Electrode along a tube window and applied zero to ${\pm}8kV$ with respect to manage the positive and negative ions formation. Lastly, the ion duty ratio was able to be controlled in different test set-ups along with a free x-ray leakage through the metallic Ring Electrode. In the result of experiment, the maximum x-ray radiation leakage was $0.2{\mu}Sv/h$. These outcome is lower than the ICRP 103 recommended value, which is $1{\mu}Sv/h$. When applying voltage to the metallic ring electrode, the positive decay time was 2.18s at the distance of 300 mm and its slope was 0.272. In addition, the negative decay time was 2.1s at the distance of 300 mm and its slope was 0.262. At the distance of 200 mm, the positive decay time was 2.29s and its slope was 0.286. The negative decay time was 2.35s and its slope was 0.293. At the distance of 100 mm, the positive decay time was 2.71s and its slope was 0.338. The negative decay time was 3.07s and its slope was 0.383. According to these research, the observation was shown that these new concept of ionizer is able to minimize the leakage radiation level and to control the positive and negative ion duty ratio while ionization.

A Study on the Green Eemission Ccharacteristics of $Alq_3$ ($Alq_3$의 녹색발광특성에 관한 연구)

  • Kang, Young-Chol;Chon, Dong-Kyu;Song, Jin-Won;Kim, Young-Keun;Kim, Ju-Seung;Gu, Hal-Bon;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.957-960
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    • 2002
  • Electroluminescence(EL) from conjugated polymers has recently received great attention because polymer light-emitting diodes(LEDs) clealy have potential for applications such as large-area displays. The operation of polymer LEDs is based on double injection of electrons and holes from the elextrodes, followed by formation of excitons whose radiative decay results in light emission at wavelength characteristic to the material. In this paper, we fabricated the single layer EL device using $Alq_3$ as emitting material. According as turn on voltage could know about 5.5V in voltage-current characteristics and voltage rise, current could see that increase as non-linear. Current and ruminance can see that express similar relativity in voltage, and could know that ruminance is expressing current relativity.

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Transient Photocurrent in Amorphous Silicon Radiation Detectors

  • Lee, Hyoung-Koo;Suh, Tae-Suk;Choe, Bo-Young;Shinn, Kyung-Sub;Cho, Gyu-Seong
    • Nuclear Engineering and Technology
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    • v.29 no.6
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    • pp.468-475
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    • 1997
  • The transient photocurrent in amorphous silicon radiation detectors (n-i-n and forward biased p-i-n) were analyzed. The transient photocurrents in these devices could be modeled using multiple trap levels in the forbidden gap. Using this model the rise and decay shapes of the photocurrents could be fitted. The decaying photocurrent shapes of the p-i-n and n-i-n devices after a short duration of light pulse showed a similar behavior at low dark current density levels, but at higher dark current density levels the photocurrent of the p-i-n diode decayed faster than that of the n-i-n, which could be explained by the decreased electron lifetimes in the forward biased p-i-n diode at high dark current densities. The transient photoconductive gain behaviors in the amorphous silicon radiation detectors are discussed in terms of device configuration, dark current density and time scale.

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Characteristics Analysis of a Small Scale Persistent Current Switch System by using Coated Conductor (Coated Conductor를 이용한 소용량 영구전류스위치 시스템의 특성 해석)

  • Kim, Yeong-Sik;Yoon, Yong-Soo;Yang, Seong-Eun;Park, Dong-Keun;Ahn, Min-Cheol;Ko, Tae-Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.9 no.1
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    • pp.47-52
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    • 2007
  • This paper presents characteristics analysis of persistent current switch(PCS) system on a small scale by using YBCO coated conductor(CC). A high temperature superconductor(HTS) PCS system mainly consists of a PCS, a HTS magnet load and a magnet power supply(MPS). To design the optimal heater triggering switch. the three-dimensional heat conduction model was analyzed by finite element method(FEM). The electrical equivalent model considering the n-value of CC was applied to analyze current decay during persistent current mode. In the experiment and simulation, the heater was applied with a current of 0.43A and the current was ramped up to 10A and 20A with 0.2A/s. Finally, experimental results of the HTS PCS system have been compared with the theoretical results. It has been concluded that flux creep can not influence the results because the operating current was 40% of critical current and optimal sequential operation of the PCS system is indispensable to enhance its performance.

A Wave Prediction Model with Current and Finite Depth Effects (흐름과 수심을 고려한 파랑 추정모형)

  • 윤종태
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.6 no.1
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    • pp.72-80
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    • 1994
  • A discrete spectral model of wind waves for arbitrary depth and current is presented This model incorporates wave growth. decay by opposite int bottom friction and wave-current interaction. Depth dependent factor was also added to the fully developed spectrum in order to consider finite depth effects. The physical behavior for the effect of depth and bottom friction was analyzed for an artificially-imposed wind field.

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Establishment of the Measurement Model about the Adequate Urban Development Density using System Dynamics (시스템다이내믹스를 활용한 도시개발밀도의 적정성 평가 모델 구축 연구)

  • 전유신;문태훈
    • Proceedings of the Korean System Dynamics Society
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    • 2003.08a
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    • pp.1-24
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    • 2003
  • The purpose of this paper was developing a development density control model for urban growth management, using system dynamics modeling. The density control model was developed to see how urban growth, transition, and decay occur depending on the interaction among population, houses, industry structure, land and urban infrastructure such as road, water supply, and sewage treatment facilities. Suggesting adequate level of development density control using the model was another purpose of this paper. The model was applied to An'yang city to estimate the maximum number of population, industry structures, houses, and cars that can be adequately sustained with the current An'yang city's infrastructur capacity. The computer simulation results shows that the city is overpopulated by some 90,000 people. To reduce the population to the adequate level that the current urban infrastructure can sustain, the current city regulation on floor area ratio are needed to be strengthened at least 20 to 35%.

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