• Title/Summary/Keyword: Atomic interface

Search Result 392, Processing Time 0.027 seconds

Distribution of Zirconium Between Salt And Bismuth During A Separation From Rare Earth Elements By A Reductive Extraction

  • S. W. Kwon;Lee, B. J.;B. G. Ahn;Kim, E. H.;J. H. Yoo
    • Proceedings of the Korean Radioactive Waste Society Conference
    • /
    • 2004.02a
    • /
    • pp.165-169
    • /
    • 2004
  • It was studied on the reductive extraction between the eutectic salt and Bi metal phases. The solutes were zirconium and the rare earth elements, where zirconium was used as the surrogate for the transuranic(TRU) elements. All the experiments were performed in a glove box filled with argon gas. Two types of experimental conditions were used -high and low initial solute concentrations in salt. Li-Bi alloy was used as a reducing agent to reduce the high chemical activity of Li. The reductive extraction characteristics were examined using ICP, XRD and EPMA analysis. Zirconium was successfully separated from the rare earth elements by the reductive extraction method. The LiF-NaF-KF system was favorable among the fluoride salt systems, whereas the LiCl-KCl system was favorable among the chloride salt systems. When the solute concentrations were high, intermetallic compounds were found near the salt-metal interface.

  • PDF

Effect of Nozzle on LBB Evaluation for Small Diameter Nuclear Piping (직경이 작은 원자력배관의 파단전누설 해석에 미치는 노즐의 영향)

  • Yu, Yeong-Jun;Kim, Yeong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.20 no.6
    • /
    • pp.1872-1881
    • /
    • 1996
  • LBB(Leak-Before-Break) analysis is performed for the highest stress location of each different type of mateerials in the nuclear piping line. In most cases, the highest stress occurs in the pipe and nozzle interface location. i.e. terminal end. The current finite element analysis approach utilizes the symmetry condition both for locations near the nozzle and for locationa away from the nozzle to minimize the size of the finite element model and to make analysis simple when calculating the J-integral values at the crack tip. In other words, the nozzle is not included in the finite element model. However, in reality, the symmetric condition is not applicable for the pipe-nozzle interface location. Because the pipe-nozzle interface location is asymmetric due to different stiffenss of the pipe and nozzle(both material and dimensions). The simplified analysis approach for pipe-nozzle interface locaiton is too conservative for a smaller diameter piping. In tlhis paper, various analyses are performed for the range of materials and crack sizes to evaluate the nozzle effect for a LBB anlaysis. This paper presents methodology for developing the piping evaluaiton diagram at the pipe-nozzle interface location.

Analysis of interface management tasks in a digital main control room

  • Choi, Jeonghun;Kim, Hyoungju;Jung, Wondea;Lee, Seung Jun
    • Nuclear Engineering and Technology
    • /
    • v.51 no.6
    • /
    • pp.1554-1560
    • /
    • 2019
  • Development of digital main control rooms (MCRs) has greatly changed operating environments by altering operator tasks, and thus the unique characteristics of digital MCRs should be considered in terms of human reliability analysis. Digital MCR tasks can be divided into primary tasks that directly supply control input to the plant equipment, and secondary tasks that include interface management conducted via soft controls (SCs). Operator performance regarding these secondary tasks must be evaluated since such tasks did not exist in previous analog systems. In this paper, we analyzed SC-related tasks based on simulation data, and classified the error modes of the SCs following analysis of all operational tasks. Then, we defined the factors to be considered in human reliability analysis methods regarding the SCs; such factors are mainly related to interface management and computerized operator support systems. As these support systems function to reduce the number of secondary tasks required for SC, we conducted an assessment to evaluate the efficiency of one such support system. The results of this study may facilitate the development of training programs as well as help to optimize interface design to better reflect the interface management task characteristics of digitalized MCRs.

Characterization and surface engineering of two-dimensional atomic crystals

  • Yu, Yeong-Jun
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2015.08a
    • /
    • pp.63.1-63.1
    • /
    • 2015
  • The next generation electronics need to not only be smaller but also be more flexible. To meet such demands, van der Waals (vdW) heterostructures using two dimensional (2D) atomic crystals such as graphene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMDCs) have been attracted intensely. In particular, for high performance of vdW heterostructures device, ultraclean interface between stacked 2D atomic crystals should be guaranteed. In this talk, I will present fabrication and characterization of the vdW field effect transistors toward performance enhancement by employing TMDCs channel, h-BN insulating layer and graphene electrode. Furthermore, it will also be introduced the characterization and surface engineering of graphene for gas molecule sensor.

  • PDF

Engineering-scale Test for Validating the T-H-M Behavior of a HLW Repository: Experimental Set-up

  • Lee, Jae-Owan;Baik, Min-Hoon;Cho, Won-Jin
    • Proceedings of the Korean Radioactive Waste Society Conference
    • /
    • 2004.06a
    • /
    • pp.194-198
    • /
    • 2004
  • The thermo-hydro-mechanical (T-H-M) process is one of major issues in the performance assessment of a high level waste (HLW) repository. An engineering-scale test was planned and its experimental set-up has being installed, to validate the T-H-M behavior in the buffer of a reference disposal system. The experimental set-up consists of 4 major components: the confining cylinder with its hydration water tank, the bentonite block, the heating system, and the sensors and instruments. The monitoring and data acquisition system is employed to control the heater to maintain the temperature of $95^{\circ}C$ at the interface of the heater and bentonite blocks and to collect signals from sensors and instruments installed in the bentonite blocks.

  • PDF

Analysis of Nano-contact Between Nano-asperities Using Atomic Force Microscopy (나노스케일 표면돌기 간의 미세접촉에 대한 해석)

  • Ahn, Hyo-Sok;Jang, Dong-Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.18 no.4
    • /
    • pp.369-374
    • /
    • 2009
  • In micro/nano-scale contacts in MEMS and NEMS, capillary and van der Waals forces generated around contacting micro-asperities significantly influence the performance of concerning device as they are closely related to adhesion and stiction of interacting surfaces. In this regard, it is of prime importance to accurately estimate the magnitude of surface forces so that an optimal solution for reducing friction and adhesion of micro/nano-surfaces may be obtained We introduced an effective method to calculate these surface forces based on topography information obtained from an atomic force microscope. This method was used to calculate surface forces generated in the contact interface formed between diamond-like carbon coating and $Si_3N_4$ ball. This method is shown to effectively demonstrate the influence of capillary force in the contact area, especially in humid atmosphere.

  • PDF

Atomic Force Microscopy Applications to the Next Generation Lithium-ion Batteries (차세대 리튬이온이차전지 연구에서의 원자력 현미경 활용)

  • Lee, Ji Hyun;Gong, Sang Hyuk;Kim, Hyeong Woo;Kim, Hyung-Seok
    • Ceramist
    • /
    • v.22 no.4
    • /
    • pp.381-392
    • /
    • 2019
  • Recently, demands for lithium-ion batteries (LIB) in various fields are increasing. In particular, understanding of the reaction mechanism occurring at the electrode-electrolyte surface/interface is significant for the development of advanced LIBs. Meanwhile, research and development of LIBs highly requires a new specific characterization approach. For example, atomic force microscopy (AFM) has been utilized to the LIB research field for various purposes such as investigation of topography, electrochemical reactions, ion transport phenomena, and measurement of surface potential at high resolution. Advances in the AFM analysis have made it possible to inspect various material properties such as surface friction and Young's modulus. Therefore, this technique is expected to be a powerful method in the LIB research field. Here, we review and discuss ways to apply AFM to LIB studies.

Atomic Layer Deposition of HfO2 Films on Ge

  • Cho, Young Joon;Chang, Hyo Sik
    • Applied Science and Convergence Technology
    • /
    • v.23 no.1
    • /
    • pp.40-43
    • /
    • 2014
  • We investigated the growth characteristics and interfacial properties of $HfO_2$ films deposited on Ge substrate through atomic layer deposited (ALD) by using an in-situ medium energy ion scattering analysis. The growth kinetics of $HfO_2$ grown on a $GeO_2/Ge$ substrate through ALD is similar to that grown on an $SiO_2/Si$ substrate. However, the incubation period of $HfO_2$ deposition on Ge is shorter than that on Si. The $HfO_2$ grown on the GeO/Ge substrate shows a significant diffusion of Hf atoms into the substrate interface and GeO volatilization after annealing at $700^{\circ}C$. The presence of low-quality Ge oxide or suboxide may degrade the electrical performance of device.

Control of solid oxide fuel cell ceramic interfaces via atomic layer deposition (원자층 증착법을 통한 고체산화물 연료전지의 세라믹 인터페이스 제어)

  • Seo, Jongsu;Jung, WooChul;Kim, Jeong Hwan
    • Ceramist
    • /
    • v.23 no.2
    • /
    • pp.132-144
    • /
    • 2020
  • Solid oxide fuel cell (SOFC) have attracted much attention due to clean, efficient and environmental-friendly generation of electricity for next-generation energy conversion devices. Recently, many studies have been reported on improving the performance of SOFC electrodes and electrolytes by applying atomic layer deposition (ALD) process, which has advantages of excellent film quality and conformality, and precise control of film thickness by utilizing its unique self-limiting surface reaction. ALD process with these advantages has been shown to provide functional ceramic interfaces for SOFC electrodes and electrolytes. In this article, recent examples of successful functionalization and stabilization on SOFC electrodes and electrolytes by the application of ALD process for realizing high performance SOFC cells are reported.

Conceptual Study of the Application Software Manager Using the Xlet Model in the Nuclear Fields (원자력 관점에서의 Xlet 모델을 이용한 응용 소프트웨어 관리자 개념 연구)

  • Joon-Koo Lee;Hee-Seok Park;Heui-Youn Park;In-Soo Koo
    • Proceedings of the Korea Society for Simulation Conference
    • /
    • 2003.11a
    • /
    • pp.59-65
    • /
    • 2003
  • In order to reduce the cost of software maintenance including software modification, we suggest the object oriented program with checking the version of application program using the Java language and the technique of executing the downloaded application program via network using the application manager. In order to change the traditional scheduler to the application manager we have adopted the Xlet concept in the nuclear fields using the network. In usual Xlet means a Java application that runs on the digital television receiver. The Java TV Application Program Interface(API) defines an application model called the Xlet application lifecycle. Java applications that use this lifecycle model are called Xlets. The Xlet application lifecycle is compatible with the existing application environment and virtual machine technology. The Xlet application lifecycle model defines the dialog(protocol) between an Xlet and its environment

  • PDF