• Steel and Composite Structures
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• v.21 no.1
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• pp.57-72
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• 2016

The Poisson ratio reduction of symmetric hygrothermal aged $[{\theta}_m/90_n]_s$ composite laminates containing a transverse cracking in mid-layer is predicted by using a modified shear-lag model. Good agreement is obtained by comparing the prediction models and experimental data published by Joffe et al. (2001). The material properties of the composite are affected by the variation of temperature and transient moisture concentration distribution in desorption case, and are based on a micro-mechanical model of laminates. The transient and non-uniform moisture concentration distribution give rise to the transient Poisson ratio reduction. The obtained results represent well the dependence of the Poisson ratio degradation on the cracks density, fibre orientation angle of the outer layers and transient environmental conditions. Through the presented study, we hope to contribute to the understanding of the hygrothermal behaviour of cracked composite laminate.

• Journal of the Korean Society of Costume
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• v.1
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• pp.59-65
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• 1977

Les modes des costumes naitonaux de $cor{\acute{e}}e$ est plus simple que celle du Occident. mais les facons, sur les quelles les mesures fondamentalement agissent, ont des $varit{\acute{e}}s$ selon les personnes qui se les habillent: masculines, $f{\acute{e}}m$ nines, jeunes, vieilles. Le but de cette ${\acute{e}}tude$ est, par l'anayse statistique des mesures, $d'{\acute{e}}tablir$ comment sont les $vari{\acute{e}}t{\acute{e}}s$. Les $r{\acute{e}}sultats$ de ce travail peuveut $\hat{e}tre$ $r{\acute{e}}sum{\acute{e}}s$ ainsi: 1. Plus $\grave{a}g{\acute{e}}s$ sont les personnes, plue larges et longues les Cheo-go-ri (vestes). 2. A propos des longeur des vestes, on les $g{\acute{e}}n{\acute{e}}ralement$ $consid{\acute{e}}re$ comme les $donn{\acute{e}}es$ principalement $subondonn{\acute{e}}es$ aux tailles des personnes $habill{\acute{e}}es$. mais a mon travail, le tour do poitrine peut-$\hat{e}tre$ le plus relatis en ce problemes. [parce que le coefficient $conr{\acute{e}}ratif$ ayant rapponts au tour de poitrine (r=0.512) est plus haut que celui qui est relatif a la taille (r=0.436).

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.157-162
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• 2002

In this study, the secure Internet phone system using digital signature and data encryption with DES algorithm and EDE algorithm was implemented. And new key distribution algorithm was suggested utilizing the Diffie-bellman algorithm. For reducing processing time, a table combined with S-BOX and P-BOX of the DES was used. The proposed system was implemented with Java and the results showed the processing time using DES algorithm for encryption was 1.46 seconds and that of EDE algorithm was 3.25 seconds respectively. This system can be applied to Protect the copyright of sound products and data using internet.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.57-62
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• 1977

Der Zuwachs des Durchmessers des Einzelbaumes kann durch die Differenzialgleichung dx/dt=k(M-x)+f(t) beschrieben werder, wobei f(t) die von den zuf$\ddot{a}$lligen $\ddot{A}$nderungen der Umwelt bedingte Fluktuation des Wachstums bedeutet. Nach dieser Gleichung kann das Wachstum des Durchmessers des Einzelbaumes in zwei Teile zerlegt werden: der erste systematische Teil k(M-x) repr$\ddot{a}$sentiert den Trend des Wachstums und der zweite Teil die Fluktuation f(t), die f$\ddot{u}$r die Wald bewirtschaftung von Praktischer Bedeutung ist. Die Studie zeigt die mathematische Ableitung zur Bestimmung von f(t).

• Structural Engineering and Mechanics
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• v.67 no.2
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• pp.165-173
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• 2018

A simple predicted model using a modified Shear-lag method was used to represent the moisture absorption effect on the stiffness degradation for $[0/90]_{2s}$ composite laminates with transverse cracks and under flexural loading. Good agreement is obtained by comparing the prediction model and experimental data published by Smith and Ogin (2000). The material properties of the composite are affected by the variation of temperature and moisture absorption. The transient and non-uniform moisture concentration distribution give rise to the transient elastic moduli of cracked composite laminates. The hygrothermal effect is taken into account to assess the changes in the normalised axial and flexural modulus due to transverse crack. The obtained results represent well the dependence of the stiffness properties degradation on the cracks density, moisture absorption and operational temperature. The composite laminate with transverse crack loaded in axial tension is more affected by the hygrothermal condition than the one under flexural loading. Through this theoretical study, we hope to contribute to the understanding of the moisture absorption on the composite materials with matrix cracking.

• Advances in aircraft and spacecraft science
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• v.6 no.4
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• pp.315-331
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• 2019

The stiffness degradation of the cross-ply composite laminates containing a transverse cracking and delamination in $90^{\circ}$ layer is predicted by using a modified shear-lag model by introducing the stress perturbation function. The prediction shows better agreement with the experimental results published by Ogihara and Takeda 1995, especially for laminates with thicker $90^{\circ}$ plies in which extensive delamination occurs. A homogenised analytic model for average transient moisture uptake in composite laminates containing periodically distributed matrix cracks and delamination is presented. It is shown that the model well describes the moisture absorption in a cross-ply composite laminate containing periodically distributed transverse matrix cracks in the $90^{\circ}$ plies. The obtained results represent well the dependence of the stiffness degradation on the crack density, thickness ratio and moisture absorption. The present study has proved to be important to the understanding of the degradation of the material propertiesin the failure process when the laminates in which the delamination grows extensively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.3
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• pp.65-78
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• 1997

Due to the cryptographic functional structure including the S-box, DES is not robust against differential cryptoanalysis (DC). Therefore, to increase the security against DC, we have to redesign the S-box or modify DES algorithm to decrease the probability for the N-1 round characteristics. However, it has been shown that a new design for the S-box is not secure enough. Rather, if will be more reliable to devise a modified cryptographic algorithm. In this paper, we propose a modified DES algorithm to decrease the probability of N-1 round characteristics to be robust against DC. According to our comparative study, the proposed algorithm is shown to be more robust against the DC than DES.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

• Journal of Life Science
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• v.22 no.3
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• pp.387-397
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• 2012

In this study, we focused on myomoduline A (MMA) released from the central nervous system of Aplysia kurodai. The primary structure of MMA is Pro-Met-Ser-Met-Leu-Arg-Leu-$NH_2$. This peptide is the same as that of the myomodulin family peptide found in other mollusks. The purified MMA showed a modulating activity of phasic contraction on the anterior byssus retractor muscle (ABRM) of Mytilus edulis. In order to study the relationship between the structure and biological activity of MMA, we synthesized MMA, Des[$Pro^1$]-MMA, Des[$Pro^1,Met^2$]-MMA, Des[$Pro^1,Met^2,Ser^3$]-MMA, and MME. The amino acid sequences of Des[$Pro^1$]-MMA, Des[$Pro^1,Met^2$]-MMA, and Des[$Pro^1,Met^2,Ser^3$]-MMA were Met-Ser-Met-Leu-Arg-Leu-$NH_2$, Ser-Met-Leu-Arg-Leu-$NH_2$, and Met-Leu-Arg-Leu-$NH_2$, respectively. MMA and synthetic peptides were tested on ABRM in M. edulis as well as muscle preparations in Achatina fulica. At $1{\times}10^{-8}$ M or lower, MMA showed a potentiating effect on phasic contraction of the ABRM, but this peptide had an inhibitory effect at $1{\times}10^{-6}$ M or higher. Both MMA and its analogs stimulated a contractile response on the crop and a relaxed catch-relaxing response on the penial retractor muscle of A. fulica. These results suggest that Met-Leu-Arg-Leu-$NH_2$ in MMA is the minimum structure required for the regulation of the contraction of ABRM, as well as the reproductive and digestive activities of mollusks.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.456-457
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• 1989