• Nuclear Engineering and Technology
• /
• v.49 no.6
• /
• pp.1250-1258
• /
• 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
• /
• v.55 no.8
• /
• pp.2785-2796
• /
• 2023

How to generate the precise broad group cross section is important for the fast reactor design. In this study, a fast reactor multi-group cross-section generation code MGGC2.0 are developed in-house for processing ultrafine group MATXS format library. Validation and verification are performed for MGGC2.0 code by applying the benchmarks of ICSBEP handbook, and the results of MGGC2.0 agree well with that of MCNP. The consistent P_N method with critical buckling search is in good agreement that condensed with TWODANT flux and flux moment for the inner core and outer core region. For the radial blanket and reflector, two region approximation method has been applied in MGGC2.0 by using collision Probability Method neutron flux solver. The RBEC-M benchmark was used to verify the power distribution calculation, and the relative error of power distribution comparison with the reference are less than 0.8% in the fuel region and the maximum relative error is 5.58% in the reflector region. Therefore, the precise broad cross section can be generated by MGGC2.0 for fast reactor.

• Economic and Environmental Geology
• /
• v.42 no.1
• /
• pp.27-53
• /
• 2009

A 30-m-thick Middle Ordovician Jigunsan Shale exposed along the southern limb of the Backunsan (Baekunsan) Syncline, Taebacksan (Taebaeksan) basin, has been simply considered as a transgressive shale sequence onlapped the underlying Maggol platform carbonates. Results of this study, however, suggest that majority of the Jigunsan Shale be interpreted as a regressive shale sequence downlapped onto a thin (ca. 240 cm) marine stratigraphic unit consisting of organic-rich (>3 wt.% of TOC) black shales in the lower Jigunsan Shale, which was accumulated at the time of maximum regional transgression. Detailed stratigraphic analysis in conjunction with XRD, XRF, and ICP-MS as well as Rock-Eval pyrolysis allows the thin marine stratigraphic unit in the Jigunsan Shale to define a condensed section that was deposited in a distinctive euxinic zone formed due to expansion of pycnocline during the early highstand phase. As well, a number of stratigraphic horizons of distinctive character that may have sequence stratigraphic or environmental significance, such as transgressive surface, maximum flooding surface, maximum sediment starvation surface, and downlap surface, are identified in the lower Jigunsan Shale. In the future, these stratigraphic horizons will provide very useful information to make a coherent regional stratigraphic correlation of the Middle Ordovician strata and to develop a comprehensive understanding on stratigraphic response to tectonic evolution as well as basin history of the Taebacksan Basin.

• Korean Journal of Medicinal Crop Science
• /
• v.14 no.1
• /
• pp.36-40
• /
• 2006

This study was carried out to investigate histological characteristics of Korean ginseng in steaming process. The Korean red ginseng were prerared with 6-years-old ginseng according to the steaming prcess and dried with $13{\pm}0.5%$ moisture and than cut in vertical section and horizontal section. The tissues are separated into epidermis, cortex, and xylem observed with Scanning Electron Microscope. The materials dried without steaming process contain cell membrane and crystallization of starch particle within them. But Korean red ginseng with prolonged steaming process are condensed, and the large hollows and cell membranes of vessel and resin duct are disappeared. In addition, Ca-oxalate rosette crystal is not found in the case of above 60-minute steaming time. The reason is that the tissues are condensed because of dry after elements' gelatinization.

• Journal of the Microelectronics and Packaging Society
• /
• v.18 no.3
• /
• pp.53-57
• /
• 2011

In the modern packaging technologies highly condensed metal interconnects are typically formed by highcost processes. These methods inevitably require the precise controls of mutually dependant process parameters, which usually cause the difficulty of the change in the layout design for interconnects of chip to-chip, or chip-to-substrate. In order to overcome these problems, the unique concept and methodology of self-assembly even in micro-meter scale were developed. In this report we focus on the factors which influenced the self-formed bumps by analyzing the phenomenon experimentally. In case of RMA flux, homogenous pattern was obtained in both plain surface and cross-section surface observation. By using RA flux, the phenomena were accelerated although the self-formtion results was inhomogenous. With ussage of moderate RA flux, reaction rate of the self-formation was accelerated with homogeneous pattern.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2002.05a
• /
• pp.63-68
• /
• 2002

Quality of industrial crops is considered to have three categories : the nutritional value, functional value, shape and appearance. The frame of this article are composed of five section : major oil crops, sesame, perilla, peanut, rape seed, and medicinals. The authors are reviewed and discussed on the current status and prospects of the quality evaluation and researches in industrial crops to provide and refers the condensed informations on the their quality.

• Korean Journal of Animal Reproduction
• /
• v.12 no.1
• /
• pp.1-10
• /
• 1988

In order to investigate the spermiogenesis of the Korean Native Jin-do dog, the tissue sampled from the testis and the epididymis of matured dog were conventionally prepared as thin sections. And then these sections were observed under a transmission electron microscope. Based on the development of various permanent organelle and certain transient structures, the spermiogenesis of the dog could be divided into four major phases: Golgi, cap, acrosome and maturation; and these phases had been futher subdivided into seven stages. In the maturatin phase, the karyoplasm has been condensed completely and the nucleus eleongated as the movement of the unclear ring. The equatorial segment has notable waist-form at the late acrosomal stage. In the cross section of the tail, it shows a typicl 9＋9＋2 pattern of the axial fiber bundle condisting of the dense fibers, the inner fibers, and a central pair. The dense fiber number 1, 5, 6, and 9 were larger in diameter than the rest of the dense fibers.

• Smart Structures and Systems
• /
• v.13 no.4
• /
• pp.637-657
• /
• 2014

This paper presents a dynamic analysis of three-dimensional beams. Structures made of functionally graded materials are considered. Several higher-order as well as classical theories are derived by means of a compact notation for the a-priori expansion order of the displacement field over the beam cross-section. The governing differential equations and boundary conditions are obtained in a condensed nuclear form that does not depend on the kinematic hypotheses. The problem is, then, exactly solved in space by means of a Navier-type solution, whereas time integration is performed by means of Newmark's solution scheme. Slender and short simply supported beams are investigated. Results are validated towards three-dimensional FEM results obtained via the commercial software ANSYS. Numerical investigations show that good accuracy can be obtained through the proposed formulation provided that the appropriate expansion order is considered.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.341-346
• /
• 2000

This experimental study investigated the flow motion of the working fluid for various diameters of miniature thermosyphons and the performance characteristics for the various amount of the working fluid. The temperatures of condenser surface were measured and visual observations were conducted. The test results show that some fluid condensed in the tube diameters of 0.18cm and 0.22cm is not returned to the evaporator section due to capillary effect so that large temperature gradients are measured. To enhance returning the working fluid, one copper wire of 0.5mm diameter was inserted and the test results show good performance. When the liquid charge was less than 10% in volume dry-out was occurred fur the thermosyphons of the inner diameter of 1.8mm and 2.2mm.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1473-1478
• /
• 2011

In this study, simulation and optimization works for a demethanizer column have been performed to obtain ethane and heavier products from a pretreated natural gas stream. Pretreated natural gas feed stream is partially condensed after being precooled by exchanging heat with demethanizer top vapor stream and by using an external refrigeration cycle with a propane refrigerant. Vapor stream is furtherly cooled and partially condensed through a turbo-expander and the power generated from the expansion of turbo-expander was delivered to the compressor for the residue gas compression. Liquid stream is being cooled by Joule-Thomson expansion valve and is fed to the middle section of the demethanizer. Ethane recovery percent for feed natural gas was set to 75% and methane to ethane molar ratio was fixed as 0.015. Propane refrigeration heat duty was reduced by splitting the feed stream and to exchange heat with side reboiler.