• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.182-190
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• 2004

An unique extraction chromatographic column (TOA: Tri-n-octylamine on Teflon powder) with a two-stage sample loading was prepared to separate Np and Pu from the environmental matrix. Np and Pu were efficiently retained in 4 M $HNO_3$ medium on the column and easily eluted with 0.02 M oxalic acid in 0.16 M HNO$_3$at $95^{\circ}C$. The separated solutions were free from most of the matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for 238U is more than 104. The instrumental detection limit for 237Np was 0.46 pg mL-l ($1.2{\times}10_{-5}$Bq mL-l), and for 239Pu was 0.48 pg mL-l ($1.1{\times}10_{-3}$ Bq mL-l). The feasibility for the determination of both elements was proved by analysing IAEA-135 reference samples, the measured values agreed with the recommended reference value.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.305-313
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• 2010

HDPE smooth and textured GMs were cut into dumbbell shape and notched where depth of the notch produced a ligament thickness of 90% to 10% of the nominal thickness of the specimen at 10% interval. Yield stress and elongation were measured of those samples and plotted on Graph. Yield stress and elongation at yield point decreases gradually as the notch depth is increased. Both installations damaged and notched GMs were used to understand stress crack behavior. Intact sample were notched in such a manner that the depth of notch produced a ligament thickness of 80% of the nominal thickness of the specimen. Installation damaged samples were not notched. Stress Crack Resistance behavior was observed using NCTL Test at $50{\pm}1^{\circ}C$ at different yield stresses immerging with pH 4 and pH 12 buffer solutions. Significant difference was observed in both cases.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.630-631
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• 2000

Sugar esters are produced by transesterification of fatty acids and sugars in organic solvent media. Chromatographic separation of sugar esters and fatty acids was investigated. $C_{18}$ column($3.9{\times}300mm$) was used in the chromatography experiment. The effect of flow rate, column temperature, and sample loading on the charateristics of chromatogram was studied. Sugar esters and fatty acids tested in this study was successfully separated with a high resolution.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.369-376
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• 2000

Parameters that represent the characteristic of consolidation have been determined by the oedometer tests. They are varied by the process of sampling and transportation, accuracy of apparatus, process of sample trimming and the skill of engineers. Also, it is difficult to grasp what factor exert a influence on the parameters. In this study, Slurry Rowe Cell Tests were peformed to evaluate the disturbance. Using the plot of e - log p which obtained from Rowe Cell test results, we compared the swelling indexes at the stress relief and the last loading stage. With that result, we tried to presume the disturbance of the 330 oedometer tests. The plot of compression-swelling index at the stress relief considerably scattered but at the last step of load shows a correlations between them. And the plot of depth-p$\sub$c/ shows a correlation with the different swelling indexes, but not in the LL-p$\sub$c/. Consequently, it is considered that the disturbance of the consolidation tests can be presumed by the comparison of the difference of swelling index.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.88-93
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• 2007

Nano-sized Sn particles were coated with Ni-P layer using an electroless deposition method and their anodic performance was tested for lithium secondary batteries. Uniform coating layers were obtained, of which the thickness was controlled by varying the $Ni^{2+}$ concentration in the plating bath. It was found that the Ni-P layer plays two important roles in improving the anodic performance of Sn powder electrode. First, it prevents the inter-particle aggregation between Sn particles during the charge/discharge process. Second, it provides an electrical conduction pathway to the Sn particles, which allows an electrode fabrication without an addition of conductive carbon. A pseudo-optimized sample showed a good cyclability and high capacity ($>400mAh\;g^{-1}$) even without conductive carbon loading.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.199-205
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• 2013

Stress and deformation on forklift happened at loading, unloading or moving freight are studied by structural and fatigue analysis in this study. As model 1 as closing type between forks has lower stress and stain than model 2 at opening type, model 1 has more durability than model 2. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'SAE bracket history' with the severest change of load at model 1 and 2, maximum life is shown with Cycle. Minimum damage with 854 at model 2 becomes much higher than model 1. As the gap between forks becomes open, the damage probability becomes higher. The structural result of this study can be effectively utilized with the safe and stable design of forklift by investigating prevention and durability against its damage.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.1-6
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• 1989

To intergrate finite elements Into CAD enviroment, design oriented structure of the finite element program is desirable. For this purpose a program called CFEP has been developed. Generation of geometry data is independently treated in the program to ease the modification of property or loading data. By conveniently handling the large number of load cases with various load combinations, and by comprehensively reporting the results through inclusive output for the multiple analyses, the program greatly facilitates the design process. Interfacing with interactive graphic post-processor, the results of analyses and final designed values are obtained in a compact and comprehensive manner. The paper also describes necessary tasks for developing such program on the economical microcomputer. Sample output of printed and graphical form well illustrates the procedure.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.809-815
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• 2007

The floor structure of railway vehicles consists of plywood, rubber, and wood keystone plate which affects on the comfort of passengers. Its structural characteristics has been investigated experimentally and numerically for samples of beam and plate structure, and the real floor structure in this paper. The material properties of etch part measured directly by experiments. The deformation and stress distribution of the sample beams for 6 different joints were sought experimentally and calculated using a commercial software. The numerical calculation shows that the effect of friction and clearance between joints is crucial. The DMU/EMU plates were also experimented and compared for different loading conditions. The structural characteristics of the whole floor structure were calculated numerically. The results show that the method of joint between plywoods is an important factor to decide the strength of the floor structure of railway vehicles.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.470-475
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• 2000

This research covers the resting of precast/prestressed concrete I-Girder bridge. The research was designed to examine processes for improving the condition evaluation and rating of prestressed concrete bridge. To establish procedures that allow for the full utilization of prestressed concrete bridge capacity, a 28-year old sample was loaded to failure in site. The bridge was constructed with 12 spans, and girders of each span were simply supported. At each loading stage, the deflections, reinforcement strains, prestressing wire strains and concrete strains were examined. Failure behavior was analyzed, and failure load was also evaluated. The test results wee compared to the analytical results from the non-linear finite element analysis.

• Journal of Ocean Engineering and Technology
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• v.19 no.2 s.63
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• pp.47-52
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• 2005

This paper introduces a procedure for free span and fatigue analysis of offshore pipelines per DNV-RP-F105, 2002. The new method includes the axial force and deflection load in pipelines. The screening criteria were established to calculate the allowable span lengths in the new design codes. The screening criteria allows a certain amount of vortex-induced vibration due to wave and current loading. However, the induced pipe stresses are very small and usually below the limit stresess of typical S-N curves. In contrast, the conventional criteria did not allow any vortex-induced vibration in the free span of pipelines. Thus, the screening criteria yields reduced allowable span lengths. A simplified procedure was established to calculate the fatigue damage due to long-term current distribution. The long-term current statistics was assumed with a 3-parameter Weibull distribution. The fatigue damage was estimated for the span lengths obtained from the screening criteria for various conditions. Sample calculations show the effect of axial force for various boundary conditions. Comparisons with conventional criteria are included.