• Smart Structures and Systems
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• 제6권2호
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• pp.167-182
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• 2010

An adaptronic strut for machine tools with parallel kinematics for compensation of the influence of geometric errors is introduced. Implemented within the strut is a piezoelectric sensor-actuator unit separated in function. In the first part of this contribution, the functional principle of the strut is presented. For use of one piezoelectric transducer as both, sensor and actuator as so-called self-sensing actuator, the acquisition of the sensing signal while actuating simultaneously using electrical bridge circuits as well as filter properties are examined. In the second part the control concept developed for the adaptronic strut is presented. A co-simulation model of the strut for simulating the controlled multi-body behavior of the strut is set-up. The control design for the strut as a stand-alone system is tested under various external loads. Finally, the strut is implemented into a model of the complete machine tool and the influence of the controlled strut onto the behavior of the machine tool is examined.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1250-1258
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• 2017

The multigroup transport theory is the basis for many neutronics modules. A significant point of the cross-section (XS) generation procedure is the choice of the energy groups' boundaries in the XS libraries, which must be carefully selected as an unsuitable energy meshing can easily lead to inaccurate results. This decision can require considerable effort and is particularly difficult for the common user, especially if not well-versed in reactor physics. This work investigates a genetic algorithm-based tool which selects an appropriate XS energy structure (ES) specific for the considered problem, to be used for the condensation of a fine multigroup library. The procedure is accelerated by results storage and fitness calculation speedup and can be easily parallelized. The extension is applied to the coupled code SIMMER and tested on the European Sustainable Nuclear Industrial Initiative (ESNII+) Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID)-like reactor system with different fitness functions. The results show that, when the libraries are condensed based on the ESs suggested by the algorithm, the code actually returns the correct multiplication factor, in both reference and voided conditions. The computational effort reduction obtained by using the condensed library rather than the fine one is assessed and is much higher than the time required for the ES search.

• Nuclear Engineering and Technology
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• 제50권2호
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• pp.237-245
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• 2018

Potential air ingress scenarios during accidents in nuclear reactors or spent fuel pools have raised the question of the influence of air, especially of nitrogen, on the oxidation of zirconium alloys, which are used as fuel cladding tubes and other structure materials. In this context, the reaction of zirconium with nitrogen-containing atmospheres and the formation of zirconium nitride play an important role in understanding the oxidation mechanism. This article presents the results of analysis of the interaction of the oxygen-preloaded niobium-bearing alloy $M5^{(R)}$ with nitrogen over a wide range of temperatures ($800-1400^{\circ}C$) and oxygen contents in the metal alloy (1-7 wt.%). A strongly increasing nitriding rate with rising oxygen content in the metal was found. The highest reaction rates were measured for the saturated ${\alpha}-Zr(O)$, as it exists at the metal-oxide interface, at $1300^{\circ}C$. The temperature maximum of the reaction rate was approximately 100 K higher than for Zircaloy-4, already investigated in a previous study. The article presents results of thermogravimetric experiments as well as posttest examinations by optical microscopy, scanning electron microscopy (SEM), and microprobe elemental analyses. Furthermore, a comparison with results obtained with Zircaloy-4 will be made.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.2830-2838
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• 2021

This work deals with the assessment of the burnup capabilities of the Serpent Monte Carlo code to predict spent nuclear fuel (SNF) isotopic concentrations for low-enriched uranium (LEU) fuel at different burnup levels up to 47 MWd/kgU. The irradiation of six UO₂ experimental samples in three different VVER-1000 reactor units has been simulated and the predicted concentrations of actinides up to ²⁴⁴Cm have been compared with the corresponding measured values. The results show a global good agreement between calculated and experimental concentrations, in several cases within the margins of the nuclear data uncertainties and in a few cases even within the reported experimental uncertainties. The differences in the performances of the JEFF3.1.1, ENDF/B-VII.1 and ENDF/B-VIII.0 nuclear data libraries (NDLs) have also been assessed and the use of the newly released ENDF/B-VIII.0 library has shown an increased accuracy in the prediction of the C/E's for some of the actinides considered, particularly for the plutonium isotopes. This work represents a step forward towards the validation of advanced simulation tools against post irradiation experimental data and the obtained results provide an evidence of the capabilities of the Serpent Monte-Carlo code with the associated modern NDLs to accurately compute SNF nuclide inventory concentrations for VVER-1000 type reactors.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.701-701
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• 2006

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 춘계학술논문요약집
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• pp.133-134
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• 2018

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2003년도 춘계종합학술대회논문집
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• pp.298-302
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• 2003

화학분야 정보 중 무기재료 합성 및 물성 연구에 필수적으로 사용되는 무기결정구조 데이터베이스를 구축하였다. 또한 국내 연구자들이 무기결정구조 정보를 웹에서 손쉽게 검색할 수 있는 웹 검색 시스템을 개발하였다. 데이터 소스는 독일의 FIZ-Karlsruhe에 의해 수집된 1915년부터의 데이터 약 65,000건을 확보하였으며 빠르고 효율적인 화합물 검색이 가능하도록 데이터베이스를 설계, 검색 시스템을 개발하였고 특히 결정구조에 대한 수치검색이 가능하도록 개발하였다.

• 대한화학회지
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• 제15권5호
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• pp.246-255
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• 1971

이 硏究는 LLewellyn/Hopkins에 依해 發展시킨 直接加熱方法을 適用하였으며 그들의 方法을 修正하여 裝置를 만들었고, 高溫에서 熱, 電氣傳導度測定에 利用하였다. $1500^{\circ}~1700^{\circ}C$에서 pyrokohlenstoff의 析出時얻은 normal-과 spiralpyrokohlenstoff에 對한 熱 및 電氣傳導度의 測定値를 Hochregenerativpyrokohlenstoff의 文獻値와 比較하였다. 그 結果 Spiralpyrokohlenstoff는 Normalpyrokohlenstoff 보다 더 좋은 熱 및 電氣傳導度를 가졌을 뿐만 아니라 $2100^{\circ}$에서 析出된 Hochregenerativpyrokohlenstoff와 경쟁할 수 있었다는 것을 發見하였다.

• 정보관리연구
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• 제23권3호
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• pp.45-73
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• 1992

특이하게 운영(運營)되는 STN International은 세계 최대의 과학기술(科學技術) 온라인 정보검색(情報檢索) 시스템으로서 세 비영리기관인 미국(美國)의 Chemical Abstracts Service, 독일(獨逸)의 FIZ Karlsruhe, 일본(日本)의 과학기술정보(科學技術情報)센터가 공동으로 운영하고 있다. 본고에서는 STN에서 빠르고 효율적인 정보검색(情報檢索)을 위해서 설계(設計)한 Messenger 검색(檢索) 소프트웨어 기능, 검색시간(檢索時間)과 노력을 줄이는 진보된 소프트웨어인 SYN Express, 그리고 STN에 수록된 데이터베이스에 관해서 기술(記述)하였다.

• Nuclear Engineering and Technology
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• 제39권4호
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• pp.249-256
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• 2007

Light water reactors operated under supercritical pressure conditions have been selected as one of the promising future reactor concepts to be studied by the Generation IV International Forum. Whereas the steam cycle of such reactors can be derived from modem fossil fired power plants, the reactor itself, and in particular the reactor core, still need to be developed. Different core design concepts shall be described here to outline the strategy. A first option for near future applications is a pressurized water reactor with $380^{\circ}C$ core exit temperature, having a closed primary loop and achieving 2% pts. higher net efficiency and 24% higher specific turbine power than latest pressurized water reactors. More efficiency and turbine power can be gained from core exit temperatures around $500^{\circ}C$, which require a multi step heat up process in the core with intermediate coolant mixing, achieving up to 44% net efficiency. The paper summarizes different core and assembly design approaches which have been studied recently for such High Performance Light Water Reactors.