• Journal of the Korean Wood Science and Technology
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• 제31권6호
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• pp.31-39
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• 2003

The enzymatic isolation of residual lignins obtained from spruce and beech pulps (obtained by sulfite, kraft, ASAM and soda/AQ/MeOH pulping processes) and their characterization was described in previous publications. Here, the residual lignins have been submitted to potassium permanganate oxidation (KMnO₄ degradation), and 9 aromatic carboxylic acids (3 of them are dimeric) were identified after methylation with diazomethane by GC/MS. The analytical challenge during qantification by the internal standard methods was the partly high protein content of the samples, which resulted in elevated anisic acid yields in the degradation mixture of sulfite residual lignins. The results are compared with the KMnO₄ degradation of the corresponding MWLs and discussed in terms of S/G ratios and degrees of condensation. The latter was calculated as a quotient between the aromatic carboxylic acids derived from condensed and non-condensed lignin structures. Typical degradation patterns for the various processes have been observed. Among other parameter, the relative compositions between iso-hemipinic acid (which is for condensation in pos. 5 of the aromatic ring) and meta-hemipinic acid and 3,4,5-trimethoxyphthalic acid (both are for condensation in pos. 6 of the aromatic ring) was found to be process specific. Kraft and soda/AQ/MeOH residual lignins yielded higher amounts of iso-hemipinic acid. In contrast, the relative yields of meta-hemipinic acid and 3,4,5-trimethoxyphthalic acid (the latter in beech lignins) are higher in sulfite and particularly in ASAM residual lignin. In case of beech residual lignins the amount of acids originated from non-condensed syringyl type lignin units was surprisingly high. The condensation degree of residual lignins was shown to be generally higher than that of MWLs. This was especially true for the G units. ASAM residual lignin exhibited very high S/G ratios and degrees of polymerization. Causality between condensation degree and total yield of degradation products was demonstrated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 반도체재료
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• pp.75-78
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• 2001

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.910-912
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• 1998

In this paper, we purpose automatic diagnosis in online, as the fundamental study to diagnose the partial discharge mechanism and to predict the lifetime, by introduction a neural network. In the proposed method, Ire use acoustic emission sensing system and calculate a fixed quantity statistic operator by pulse number and amplitude. Using statically operators such as the center of gravity(G) and the gradient of the discharge distribute(C), we analyzed the early stage and the middle stage. the fixed quantity statistic operators are learned by a neural network. The diagnosis of insulation degradation and a lifetime prediction by the early stage time are achieved. On the basis of revealed excellent diagnosis ability through the neural network learning for the patterns during degradation, it was proved that the neural network is appropriate for degradation diagnosis and lifetime prediction in partial discharge.

• Structural Engineering and Mechanics
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• 제75권1호
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• pp.19-32
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• 2020

Due to repetitive traffic loadings and environmental attacks, reinforced concrete (RC) bridge deck slabs are suffering from severe degradation, which makes structural repairing an urgency. In this study, the fatigue performance of an RC bridge deck repairing technique using ultra-high performance fiber reinforcement concrete (UHPFRC) overlay is assessed experimentally with a wheel-type loading set-up as well as analytically based on finite element method (FEM) using a crack bridging degradation concept. In both approaches, an original RC slab is firstly preloaded to achieve a partly damaged RC slab which is then repaired with UHPFRC overlay and reloaded. The results indicate that the developed analytical method can predict the experimental fatigue behaviors including displacement evolutions and crack patterns reasonably well. In addition, as the shear stress in the concrete/UHPFRC interface stays relatively low over the calculations, this interface can be simply simulated as perfect. Moreover, superior to the experiments, the numerical method provides fatigue behaviors of not only the repaired but also the unrepaired RC slabs. Due to the high strengths and cracking resistance of UHPFRC, the repaired slab exhibited a decelerated deterioration rate and an extended fatigue life compared with the unrepaired slab. Therefore, the proposed repairing scheme can afford significant strengthen effects and act as a reference for future practices and engineering applications.

• 한국전기전자재료학회논문지
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• 제20권2호
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• pp.188-193
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• 2007

Tracking and erosion of Poly Methyl Methacrylate (PMMA) and the suppression mechanism of alumina trihydrate were investigated in the present study The conventional testing as IEC-60587 is widely used in surface aging measurement of outdoor insulator those testing can carry out very short time for Lab testing. Also IEC-60587 testing is able to offer the standard judgement of relative degradation level of outdoor HV system. Therefore it is very useful method compare to previous conventional tracking testing method, But surface discharges(SD) have very complex characteristics of discharge pattern so it is required estimation research to development of precise analysis method. In recent, the study of IRR-Camera is carrying out discover of temperature of power equipment through condition diagnosis and system development of degradation diagnosis. In this paper, SD occurred from IEC-60587 is measured with the surface temperature of weibull distribution in real time, the degradation grade of SD is analyzed through produced patterns in IEC-60587 using Infrared Radiation(IRR) camera.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마
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• pp.50-54
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• 2000

Recently, the HFPD measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Also HFPD testing is able to offer the judgement standard of degradation level of HV machine and can detect discharge signals in live-line. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires live-line diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In recent, the study of partial discharge is carrying out discover of initial defect of power equipment through condition diagnosis and system development of degradation diagnosis using HFPD(High Frequency Partial Discharge) detection. In this study, simulated transformer is manufactured and HFPD occurred from transformer is measured with broad band antenna in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages.

• 대한금속재료학회지
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• 제48권7호
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• pp.674-682
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• 2010

Fe-fullerene/$TiO_2$ composite photocatalysts were prepared with titanium (IV) n-butoxide (TNB) by a sol-gel method. The samples were characterized by scanning electron microscopy (SEM), Transmission electron microscope (TEM), specific surface area (BET), X-ray diffraction analysis (XRD) and energy dispersive X-ray spectroscopy (EDX). The photocatalytic activities were evaluated by the photocatalytic degradation of methylene blue (MB) solution. XRD patterns of the composites showed that the Fe-fullerene/$TiO_2$ composite contained a typical single and clear anatase phase. The surface properties shown by SEM present a characterization of the texture on Fe-fullerene/$TiO_2$ composites and showed a homogenous composition in the particles for the titanium sources used. The EDX spectra for the elemental identification showed the presence of C and Ti with strong Fe peaks for the Fe-fullerene/$TiO_2$ composite. From the photocatalytic results, the excellent activity of the Fe-fullerene/$TiO_2$ composites for degradation of methylene blue under UV light irradiation could be attributed to both the effects between photocatalytic reaction of the supported $TiO_2$, decomposition of the organometallic reaction by the Fe compound and energy transfer effects such as electron and light of the fullerene.

• 한국가금학회지
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• 제49권4호
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• pp.265-272
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• 2022

Many studies on poultry have been conducted in the poultry industry to improve their important economic traits, such as egg production, meat quality, and carcass yield. Environmental changes affect the poultry's economic traits, including muscle growth. The purpose of this study is to investigate the mechanisms by which simvastatin causes muscle injury in quail muscle cells. Following treatment with various doses of simvastatin, LD50 in the quail myoblast cells was determined using a cell viability test; cell death was caused by apoptosis and/or necrosis. Thereafter, the expression patterns of the atrophy marker genes were examined via quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The results showed that the transcriptional levels of the muscle atrophy marker genes (Atrogin-1, TRIM63) and the upstream genes in their signaling cascade were increased by simvastatin treatment. This indicated that simvastatin induced myogenic cell death and muscle injury via protein degradation through muscle atrophy signaling. Further studies should focus on identifying the mechanism by which simvastatin induces the protein degradation signaling pathway in quail muscle..

• 대한화학회지
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• 제58권2호
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• pp.205-209
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• 2014

Hematite iron oxide (${\alpha}$-$Fe_2O_3$) nanowalls were fabricated on aluminum substrate by a facile solvent-assisted hydrothermal oxidation process. The XRD and EDS patterns indicate that the sample has a rhombohedral phase of hematite $Fe_2O_3$. FE-SEM, TEM, HR-TEM, SA-ED were employed to characterize the resulting materials. $N_2$ adsorption-desorption isotherms was used to study a BET surface area. Their capability of catalytic degradation of titan yellow GR azo dye with air oxygen in aqueous solution over $Fe_2O_3$ catalysts was studied. The result indicates that the as-prepared product has a high catalytic activity, because it has a larger surface area. Langmuir and Freundlich isotherms of adsorption dye on the catalysts surface were investigated and the decomposition of titan yellow GR follows pseudo-first order kinetic.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제2권1호
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• pp.33-37
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• 2002

Insulation aging diagnosis system provides early warning regarding electrical equipment defects. Early warning is very important in that it can avoid great losses resulting from unexpected shutdown of the production line. Since relations of insulation aging and partial discharge dynamics are non-linear. it is very difficult to provide early warning in an electrical equipment. In this paper, we propose the design method of insulation aging diagnosis system that use a electromagnetic wave and acoustic signal to diagnose an electrical equipment. Proposed system measures the partial discharge on-line from DAS(Data Acquisition System and acquires 2D patterns from analyzing it. For filtering the noise contained in sensor signals we used ICA algorithms. Using this data, we design of the neuro-fuzzy model that diagnoses an electrical equipment and is investigated in this paper. Validity of the new method is asserted by numerical simulation.