• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1608-1618
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• 2005

The purpose of this investigation was to investigate the degradation products of the dye component extracted from madder dyed fabrics using the GC-MS analysis and to evaluate the change of color due to degradation treatment. Four different degradation protocols were used in this study,; refrigeration at $7^{\circ}C$ (LT), room temperature (RT), oven treatment at $100^{\circ}C$ (OV), and $H_2O_2/UV(PER)$ method. Degradation times for each thermal system were 6 hour, 24 hour, 48 hour, 1 week, 2 week, 4 week. Alizarin was detected from the control and degraded samples of both alizarin dyed and madder dyed fabrics. Benzoic acid, 2, 4-di-tert-butylphenol, phthalic anhydride were detected as the degradation products for both alizarin dyed and madder dyed fabrics. The result suggest that these products can be used as the fingerprints of GC-MS analysis for the identification of madder dye in archaeological textiles. Both alizarin dyed and madder dyed samples became less red and less yellow after degradation. In the PER degradation system madder dyed sample showed the greatest color difference even after 1 week of degradation treatment. Further research is necessary for investigating the color change in the exhumed textiles, which is caused by the dual action of dye fading and the staining of organic matters in the soil.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.6 s.165
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• pp.859-868
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• 2007

Degradation products of the dye extracted from turmeric and the turmeric dyed textiles were examined by using GC-MS after 100 oven (OV) and $H_2O_2/UV/O_2$(PER) treatments for up to 28 days. Throughout the OV degradation times, 2-propenoic acid, 3-(2-hydroxyphenyl)- was found consistently, while isovanillin, and vanillic acid were newly detected. In 28 day PER degradation sample, feruloylmethane, 2-propenoic acid, 3-(2-hydroxyphenyl)-, benzoic acid, and vanillic acid were detected as well as isovanillin. Feruloylrnethane, and 2-propenoic acid, 3-(2-hydroxyphenyl)- were detected from the degraded fabric samples. With the absence of curcuminoids in the GC-MS result, the decreasing pattern of 2-propenoic acid, 3-(2-hydrokyphenyl)- reflect the degradation of curcuminoids in turmeric extraction with the progression of OV degradation times. It is suggested that isovanillin, feruloylmethane, 2-propenoic acid,3-(2-hydroxyphenyl)-, and vanillic acid are the probable fingerprint products for determining the turmeric dye from the badly faded archaeological textiles.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.4
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• pp.481-494
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• 2001

An enhanced degenerated shell finite element (FE), which has been developed for inelastic analysis of reinforced concrete structures is described in this paper. Generally, Reissner-Mindlin (RM) assumptions are adopted to develop the degenerated shell FE so that transverse shear deformation effects is considered. However, it is found that there are serious defects such as locking phenomena in RM degenerated shell FE since the stiffness matrix has been overestimated in some situations. As remedies of locking phenomena, reduced integration, incompatible mode and assumed strain method have been used. Especially, the assumed strain method has been successfully used in many FEs. But contrarily, there is a few investigation on the performance of the assumed strains in the inelastic analysis of concrete structures. Therefore, shell formulation is provided in this paper with emphasis on the terms related to the stiffness matrix based on assumed strain method and microscopic concrete material model. Finally, the performance of the present shell element is tested and demonstrated with several numerical examples. From the numerical tests, the present result shows a good agreement with experimental data or other numerical results.

• Solar Energy
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• v.15 no.3
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• pp.141-149
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• 1995

The tungsten oxide thin films were prepared on $s_i$ wafer by using an electron-beam evaporation technique. Thickness and structure of tungsten oxide film degraded in various electrolytes were analyzed by Rutherford backscattering spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscope. Thickness of $WO_3$ film was the most dissolved in 1M $H_2SO_4$ electrolytye. We have confirmed that the degradation of this films was accelerated by $H_2O$ in electrolytes. But the electronic structure of film degraded by electrolyte contained of glycerol was not changed as comparision with as-deposited film. The degradation may be attributed to a change of thickness and the surface morphology of the film.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.2002-2010
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• 2009

The degradation behavior of berberine is examined using GC-MS to select the fingerprint products that can be used to identify berberine dye in badly faded archaeological textiles. A total of $100^{\circ}C$ thermal and $H_2O_2/UV/O_2$ degradation systems were used to degrade berberine chloride 0.1% solution up to 408 hours. The samples were analyzed using the GC-MS. Dihydroberberine, 2-pteridinamine, 6,7-dimethyl-N-[(trimethylsilyl) oxy]-, and 8-methoxy-11-[3-methylbutyl]-11H-indolo[3,2-c]-quinoline, 5-oxide were detected as the major products of thermal degradation and identified as the fingerprint products for berberine dye at the early stage of degradation. Isobenzofuran-1,3-dione,4,5-dimethoxy-, 9H-fluorene,3,6-bis(2-hydroxyethyl)-,1,3-dioxolo[4,5-g]isoquinolin-5(6H)-one,7,8-dihydro-, and 3-tert-butyl-4-hydroxyanisole were detected as the major products generated by the $H_2O_2/UV/O_2$ degradation and identified as the fingerprint products for berberine dye under severe degradation conditions.

• Korean Journal of Materials Research
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• v.5 no.5
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• pp.575-582
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• 1995

Al 8090합금의 퇴화처리시에 나타나는 금속간화합물 변화과정과 PFZ 생성 및 입계석출물의 거동을 TEM을 사용하여 조사하였다. 기지에서는 $\delta$상, T$_{1}$ 상과 S'상이 모든 시편에서 관찰되었고, 입계어슨 PFZ이 형성되었다. 본 연구에 사용된 Al합금의 초기PFZ의 생성 기구는 입계의 임계공공 농도에 의한 것으로 나타났다. 2단계 열처리시 시간이 2분 이상이면 입계에 석축물이 형성되었다. 입계에는 중간단계로 5회전대칭축을 가지는 준안전상의 icosahedral상의 생성되었다. 평형 입계석출물은 사방정의 $Al_{13}$Fe$_{4}$였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.353-364
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• 2007

In this paper, a nonlinear finite element analysis program NUCAS, which has been developed for assessment of ultimate pressure capacity and failure mode for nuclear containment building is described. Degenerated shell element with assumed strain method and low-order solid element with enhanced assumed strain method is adapted to microscopic material and elasto-plastic material model, respectively. Finally, the performance of the developed program is tested and demonstrated with several examples. From the numerical tests, the present results show a good agreement with experimental data or other numerical results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.322-327
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• 1995

Experiments were conducted to know the relationships between seed quality and leakage of sugars from differently-aged seeds of rape, Chinese cabbage and radish. Seeds were artificially aged at 90% relative humidity and 45$^{\circ}C$ to get different seed qualities. Significant amounts of total sugars were leaked from the dead seeds of all crops during the 8~24 hours soaking period, while high quality seeds leaked negligible amounts of total sugars. High quality seeds of all crops contained lots of sucrose and glucose and some stachyose, raffinose and fructose. During the artificial aging of seeds stachyose, raffinose, and sucrose decreased, while glucose and fructose increased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.235-242
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• 2011

The control performance in active structural control system can be drastically deteriorated when the modeling errors and the uncertainties existing in the disturbances are disregarded in the designing stage. It can even throw the control system into an unstable phase, resulting in out of control against the seismic excitations. The purpose of the study is to investigate the control effectiveness of a non-linear control system called sliding mode controller(SMC) in cooperation with a Tuned Mass Damper subjected to the three seismic excitations selected from the FFT analysis. Even though the transient performance such as settling time and overshoot were deteriorated, the robustness against the system stability was appeared from SMC when the structural masses and stiffness perturbed within the range of ${\pm}30%$. SMC is a feasible technique for active structural control in cooperation with TMD against seismic disturbances, exhibiting robustness in perturbation of system stiffness and mass as well as uncertainties of the disturbances.

• Korean Journal of Materials Research
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• v.6 no.10
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• pp.1025-1033
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• 1996

본 연구에서는 0.5M NaCI 용액내에서 일어나는 고분자재료로 피복된 강의 퇴화현상을 광학현미경 관찰 및 A.C. impedance spectroscopy를 이용하여 연구하였다. 강의 부식은 고분자재료로 피복된 강의 경우 국부부식(localized corrosion)의 형태로 나타난 반면, 피복되지 않은 강의 경우에는 전면부식(uniform corrosion)의 형태로 진행되었다. 고분자재료로 피복된 강의 부식이 국부적으로 진행되는 것은 피복층내에 존재하는 기공이나 크랙과 같은 결함 등에서 부식이 선택적으로 일어나기 때문으로 사료된다. 피복층의 박리(delamination) 현상은 고분자재료로 피복된 강/구리 갈바닉쌍(galvanic couple)의 경우 구리표면 위의 피복층에서만 관찰되었다. 이는 캐소드(cathode)로 작용하는 구리의표면에서 산소의 환원반응에 의해서 형성된 수산화이온(OH-)이 피복층의 박리를 조장하고 있음을 보여준다. 또한, 고분자재료 피복층의 파손 현상은 고분자재료/강의계면에서 석출된 부식생성물에 의해서 크게 조장되고 있음을 알 수 있다.