• Progress in Superconductivity
• /
• v.3 no.2
• /
• pp.247-251
• /
• 2002

In general, the bubbling, generated during the fabrication of the tapes, breaks the superconducting filament, and critical current of the tapes will be decreased. Heat-treatment schemes of Bi-2223/Ag HTS tapes were modified, such as pre-annealing of multi-stacked billet, 2-step main sintering and ramp rate etc. The generation of bubbling was drastically decreased from 20 bubbles/m to 0 ~ 1 bubble/m by the modified heat-treatment. Therefore, the value of critical current of the tapes without bubbling was increased almost twice higher than that of already existing tapes. Critical current up to 42 A in 40 m length Bi-22231Ag tapes have been measured at 77K, self-field, 1$mutextrm{V}$/cm criterion. It could be confirmed that elimination of bubbling is effective to maintain the superconducting property along the tape length.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1279-1280
• /
• 2006

병렬선재를 사용하여 권선을 제작할 경우 구성하는 초전도 선재의 임피던스의 차이에 의하여 통전전류 불균형이 발생하게 된다. 본 논문에서는 BSCCO 선재를 사용하여 제작된 병렬선재에서 전류불균형 분포에 따른 교류손실을 측정하였다. 4 가닥 병렬선재의 경우 전류 불균형이 발생한 선재에서의 교류손실이 전류 불균형이 일어나지 않을 때보다 2배 이상 증가함을 확인하였다.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.845-846
• /
• 2006

Reduce AC loss is very important in superconductor power machine. And HTS power application are needed an increment of current capacity. in this paper estimate AC loss effect and increase of current according tocomposition stack with 1G wire and 2G wire by measurement. A Method of composition stack are YBCO-BSCCO, YBCO-BSCCO-BSCCO-YBCO and BSCCO-YBCO-YBCO-BSCCO. also, test result compared analytic equation by Norries

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1739-1740
• /
• 2006

병렬선재를 사용하여 권선을 제작할 경우 구성하는 초전도 선재의 임피던스의 차이에 의하여 통전전류 불균형이 발생하게 된다. 본 논문에서는 BSCCO 선재를 사용하여 제작된 병렬선재에서 전류불균형 분포에 따른 교류손실을 측정하였다. 4 가닥 병렬선재의 경우 전류 불균형이 발생한 선재에서의 교류손실이 전류 불균형이 일어나지 않을 때보다 2배 이상 증가함을 확인하였다.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.945-947
• /
• 2005

변압기, 케이블, 한류기와 같은 고온초전도 선재의 전력기기의 개발과 응용에 있어서 교류손실은 기기의 운용과 효율에 밀접한 관계가 있기 때문에 중요한 연구 분야가 되고 있다. 또한 현재 전력기기에 응용 하고 있는 고온초전도 선재는 전력기기에 필요한 통전용량을 수용 할 수 없기 때문에 이를 해결하기 위한 방법으로 선재를 적층하여 통전용량을 증대시키는 다양한 방법이 연구되고 있다. 본 논문에서는 고온초전도 선재의 적층배열을 달리 하였을 때, 외부자계에 의한 고온초전도 선재의 자화손실 특성에 대해서 연구하였다. 선재의 적층 배열의 형상은 Edge-to-Edge, Face-to-Face형과 Matrix형이며, 적층배열에 사용한 선재의 개수는 2, 4, 8개이다. 연구결과, 동일한 적층 수의 조건하에서 Face-to-Face형의 적층배열이 다른 종류의 배열보다 자화손실이 낮음을 확인하였고, 이는 Face-to-Face 형태로 적층 될 때 인접선재로 인한 자기차폐효과가 다른 배열의 경우보다 우수하기 때문으로 보인다.

• Journal of Species Research
• /
• v.9 no.2
• /
• pp.131-146
• /
• 2020

Siphonophores are unique, gelatinous zooplankton, which many individuals gather and live like one "Superorganism". The role of individuals in the colony differs greatly depending on their morphological difference, making them more unique. In this study, we report four species belonging to Diphyidae Quoy and Gaimard, 1827 sampled from the South Sea and off Jeju Island, Korea. Two Chelophyes Totton, 1932 (C. appendiculata (Eschscholtz, 1829); C. contorta (Lens and van Riemsdijk, 1908)) and two Eudoxoides Huxley, 1859 (E. mitra (Huxley, 1859); E. spiralis (Bigelow, 1911)) species are described with multi-focus stacked digital images. Our findings update the confirmed order Siphonophorae Eschscholtz, 1829 in Korea to be three suborders, five families, eight genera, and 13 species. In addition, we summarize the synonyms and global distributions of these four newly recorded species in Korean waters.

• Journal of Information Processing Systems
• /
• v.13 no.5
• /
• pp.1052-1070
• /
• 2017

For the autoencoder (AE) implemented as a construction component, this paper uses the method of greedy layer-by-layer pre-training without supervision to construct the stacked autoencoder (SAE) to extract the abstract features of the original input data, which is regarded as the input of the logistic regression (LR) model, after which the click-through rate (CTR) of the user to the advertisement under the contextual environment can be obtained. These experiments show that, compared with the usual logistic regression model and support vector regression model used in the field of predicting the advertising CTR in the industry, the SAE-LR model has a relatively large promotion in the AUC value. Based on the improvement of accuracy of advertising CTR prediction, the enterprises can accurately understand and have cognition for the needs of their customers, which promotes the multi-path development with high efficiency and low cost under the condition of internet finance.

• International Journal of High-Rise Buildings
• /
• v.9 no.4
• /
• pp.377-386
• /
• 2020

Beginning a few decades ago, Baku, the capital city of Azerbaijan, has experienced a dramatic construction boom that is revitalizing its skyline. The expansive growth looks to uphold the historic past of Baku as a focal point within the Caspian Sea Region while also evoking aspirations for a city of the future. With superstructure complete and interiors progressing, the Ministry of Taxation (MOT) tower is the latest addition to the city, with its stacked cubes twisting above a multi-level podium at the base. Each cube is separated by column-free green roof terraces, creating unique parametric reveals of the developing surroundings. Aside from MOT's stunning shape, its geolocation resulted in unusually high wind loads coupled with high seismic hazards for a tower of its height. In addition, limitations on possible structural systems required stepping away from a typical prescriptive code-based approach into one that utilized Performance-Based Design (PBD) methods. This paper presents the numerous structural challenges and innovations that allowed the design of a new icon to be realized.

• Progress in Superconductivity and Cryogenics
• /
• v.24 no.1
• /
• pp.1-7
• /
• 2022

So far, large-scale scientific devices such as nuclear fusion tokamaks and high energy circular accelerators were constructed using high-current conductors made of metallic superconducting wires. Recently, as REBCO superconducting wires usable in high magnetic fields have been developed by several companies, researchesto apply high current cable type REBCO conductors to next-generation large superconducting magnets were also started. High critical currents of several kA or more in high magnetic fields have been successfully demonstrated on test samples of REBCO cable conductors by several research groups. In this review article, the main features and properties of the representative high current REBCO conductors such as CORC(Conductor On Round Core), TSTC(Twisted Stacked-Tape Cable) and RACC(Roebel-Assembled Coated Conductor), which are currently being developed at abroad are briefly introduced. Research activities of high-current density REBCO MHOS(Multi HTS layers on One Substrate) conductor at KERI, whose structure is different from other cable type REBCO conductors are also shortly introduced.

• Nuclear Engineering and Technology
• /
• v.54 no.6
• /
• pp.2262-2275
• /
• 2022

The Korea Atomic Energy Research Institute (KAERI) studied the sodium-water reaction (SWR) minimized steam generator for the safety of the sodium-cooled fast reactor (SFR), and selected the copper bonded steam generator (CBSG) as the optimal concept. This paper introduces the conceptual design of the CBSG and the development of the CBSG sizing analyzer (CBSGSA). The CBSG consists of multiple heat transfer modules with a crossflow heat transfer configuration where sodium flows horizontally and water flows vertically. The heat transfer modules are stacked along a vertical direction to achieve the targeted large heat transfer capacity. The CBSGSA code was developed for the thermal-hydraulic analysis of the CBSG in a multi-pass crossflow heat transfer configuration. Finally, we conducted a preliminary sizing and rating analysis of the CBSG for the trans-uranium (TRU) core system using the CBSGSA code proposed by KAERI.