• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.262-268
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• 2022

This paper introduces a novel concept of the pulsed neutron facility (PNF) for maximizing the production of the thermal neutrons and its application to medical use based on prompt gamma neutron activation analysis (PGNAA) using Monte Carlo simulations. The PNF consists of a compact D-T neutron generator, a graphite pile, and a detection system using Cadmium telluride (CdTe) detector arrays. The configuration of fuel pins in the graphite monolith and the design and materials for the moderating layer were studied to optimize the thermal neutron yields. Biological samples - normal and cancerous breast tissues - including chlorine, a trace element, were used to investigate the sensitivity of the characteristic γ-rays by neutron-trace material interactions and the detector responses of multiple particles. Around 90 % of neutrons emitted from a deuterium-tritium (D-T) neutron generator thermalized as they passed through the graphite stockpile. The thermal neutrons captured the chlorines in the samples, then the characteristic γ-rays with specific energy levels of 6.12, 7.80 and 8.58 MeV were emitted. Since the concentration of chlorine in the cancerous tissue is twice that in the normal tissue, the count ratio of the characteristic g-rays of the cancerous tissue over the normal tissue is approximately 2.

• Tunnel and Underground Space
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• v.24 no.1
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• pp.46-54
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• 2014

Direct shear tests have been initiated to understand the characteristics of joints which crucially affect the stability of rock mass. In this research, numerical approach in direct shear tests has been initiated using 3DEC on the basis of 3D distinct element method. Normal loads were altered in four different levels on artificial joint tests depending on the sawtooth angle and strengths on constant normal stress conditions, measuring the peak shear strength according to the direct shear tests under laboratory condition. Also results obtained from mechanical properties through laboratory test were used to perform numerical modeling, and shear strength obtained from the modeling was used to compare with laboratory direct shear test. As a result numerical analysis from distinct element method can simulate well on the shear behavior of rockmass.

• Structural Engineering and Mechanics
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• v.68 no.4
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• pp.385-398
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• 2018

In the present paper, we offer a new flat shell finite element. It is the result of the combination of a membrane element and a bending element, both based on the strain-based formulation. It is known that $C^{\circ}$ plane membrane elements provide poor deflection and stress for problems where bending is dominant. In addition, they encounter continuity and compliance problems when they connect to C1 class plate elements. The reach of the present work is to surmount these problems when a membrane element is coupled with a thin plate element in order to construct a shell element. The membrane element used is a triangular element with four nodes, three nodes at the vertices of the triangle and the fourth one at its barycenter. Each node has three degrees of freedom, two translations and one rotation around the normal. The coefficients related to the degrees of freedom at the internal node are subsequently removed from the element stiffness matrix by using the static condensation technique. The interpolation functions of strain, displacements and stresses fields are developed from equilibrium conditions. The plate element used for the construction of the present shell element is a triangular four-node thin plate element based on Kirchhoff plate theory, the strain approach, the four fictitious node, the static condensation and the analytic integration. The shell element result of this combination is robust, competitive and efficient.

• Proceedings of the Korean Geotechical Society Conference
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• 1987.06a
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• pp.51-80
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• 1987

In this studys a numerical analysis on the defomation of foundation layer was carried out by indroducing joint element. The method using the joust element between adj assent different materials has been originally developed for rock behavior(Goodman, et al. 1968) . The application of this method to the interface between the footing and soil layer proved satisfactory(Ghaboussi p et at. 1973). Authors tried to obtain the deformation of rrcompound foundation layerg", which vertically or horizontally or both consists of the natural(or intact) soft clay layer and the layer improved artificially in order to get high stiff-fness with replacement or chemical treatment to reduce the excessively detrimental settlemellt or lateral displacement in case of banking or building the civil structure on the soft layer. The joint conditions were classified into three categories : contacts sliding and separation. By coupling "JOINT" as a subroutine into multi-purpose code for the finite element method of the foundatlion daveloped by authors on the assumption that shearing and normal displacement can not be coupledl which terms pinon-dilatant" and by selecting modified Cam-clay modeIP the deformation analysis was performmed. The results using joint element were compared with those secured without introduction of joint element Nain results analized are as follows : 1. For the prediction of settlement and lateral desplacement, the result due to joint element was evaluated larger, which was regarded safe. 2. For the determination of ultimate bearing capacetyi the value using joint element appeared smaller by 20%, which was also safe.

• BMB Reports
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• v.32 no.1
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• pp.45-50
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• 1999

We previously found three transcription factor-binding motifs in the rat p53 promoter. They are two recognition motifs of NF1-like protein (NF1-like element 1: -296 ~ -312, NF1-like element 2: -195 ~ -219) and a bHLH protein binding element (-142 ~ -146). In this study, we investigated the DNA-protein complex formation of the three elements with nuclear extracts from both normal and regenerating liver to find the element involved in the induced transcription of p53. The level of each DNA-protein complex on NF1-like and bHLH motifs was not changed. Instead, a new element located at -264 ~ -284 was detected in the DNase I footprinting assay with regenerating nuclear extract. This element has partial homology to the AP1 consensus motif. However, the competition studies with diverse oligonucleotides suggest that the binding protein is not AP1. An in vitro transcription assay shows that this element is important for the transcriptional activation of the rat p53 promoter. Therefore, for the induced transcription of the rat p53 promoter, the-264 ~ -284 region is required in addition to two NF1-like and one bHLH motif.

• Bulletin of the Korean Mathematical Society
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• v.48 no.4
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• pp.759-767
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• 2011

An element of a ring is called strongly nil clean provided that it can be written as the sum of an idempotent and a nilpotent element that commute. A ring is strongly nil clean in case each of its elements is strongly nil clean. We investigate, in this article, the strongly nil cleanness of 2${\times}$2 matrices over local rings. For commutative local rings, we characterize strongly nil cleanness in terms of solvability of quadratic equations. The strongly nil cleanness of a single triangular matrix is studied as well.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.36-39
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• 2000

The main issues for the power application of high Tc superconducting tape are lower AC loss and higher stability conditions. HTS tape has large stability margin by high heat capacity of superconductor itself and high temperature margin. But, it can be damaged by continuous heat generation at quench point, because normal zone propagation velocity by generating heat is very low. Here, we analyze the quench propagation characteristics using finite element method for BSCCO-2223 HTS tape.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.674-676
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• 2008

An electrostatic discharge (ESD) or a noise supplied from the outside has an effect on communication between the timing controller (TCON) and the memory element (EEPROM) through the interface between the timing controller and the memory element in liquid crystal displays (LCD). Therefore, we must apply ESD protection methods to LCD operating circuits for a normal operation. Our ESD protection circuit is to prevent from bi-directional communication errors between TCON and EEPROM due to an electrostatic discharge (ESD).

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.5
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• pp.77-84
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• 1992

In the most of acoustic system with low flow rate and low pressure level, one-dimensional, linear modeling techniques are used very well. At low frequency, the tube is modeled as inertia element and cavity as capacitance element, and to extend the range of frequency normal mode oscillators are represented. Bond graph modelling techniques are proposed to predict TL (Transmission Loss) and time response which is impossible by transfer matrix in muffler system. A simple acoustic filter which consists of several tubes and cawities is analyzed in both time and frequency domain.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1601-1610
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• 1991

본 연구에서는 3차원 스트레칭 문제의 2차원화가 가능한 주요 단면에 대해서 박막요소와 적층 셸(degenerated shell) 요소를 혼합하여 사용하는 선택적 M/S 방법을 이용하여 2차원 문제로 해석하였다. M/S변환 조건으로는 변형형상의 기하학적 조건 을 고려하였다.