• Transactions on Electrical and Electronic Materials
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• v.6 no.6
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• pp.262-271
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• 2005

In order to achieve timely and accurate fault detection of plasma etching process, neural network based time series modeling has been applied to reactive ion etching (RIE) using two different in-situ plasma-monitoring sensors called optical emission spectroscopy (OES) and residual gas analyzer (RGA). Four different subsystems of RIE (such as RF power, chamber pressure, and two gas flows) were considered as potential sources of fault, and multiple degrees of faults were tested. OES and RGA data were simultaneously collected while the etching of benzocyclobutene (BCB) in a $SF_6/O_2$ plasma was taking place. To simulate established TSNNs as incipient fault detectors, each TSNN was trained to learn the parameters at t, t+T, ... , and t+4T. This prediction scheme could effectively compensate run-time-delay (RTD) caused by data preprocessing and computation. Satisfying results are presented in this paper, and it turned out that OES is more sensitive to RF power and RGA is to chamber pressure and gas flows. Therefore, the combination of these two sensors is recommended for better fault detection, and they show a potential to the applications of not only incipient fault detection but also incipient real-time diagnosis.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.85-91
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• 2001

This paper presents safety analysis of LNG leakage in a prestressed concrete outer tank, which is strongly related on the leak checking effects of the PC structure with and without a residual compression zone based on the BS 7777 codes. The full containment type outer tank which is constructed by a prestressed concrete may be destroyed by leaked cryogenic fluids. The FE calculated results show that the total leak checking time of the PC structure with $10\%$ residual compression zone is about 9 days for $-162^{\circ}C$ liquids. But, three primary pumps in an inner tank may operate to send cryogenic fluids for 6 days, which are stored in an inner tank of $140,000m^3$ capacity This means that the prestressed concrete outer tank may be safe for $-162^{\circ}C$ cryogenic fluids leaked from the demolished inner tank.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.103-103
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• 2009

As the size of containership increased over 14,000TEU, thick steel plate with high strength has been used. The plate thickness increased over 70mm and yield strength of the steel plate was around $47kg_f/mm^2$. Many researchers reported that the thick welded plate has low crack arrest toughness. They noticed the crack arrest ability is dependent on the plate thickness. In other words, brittle crack propagates straightly along the welded line and make abrupt fracture in the thick plate which causes low $K_{ca}$. In this study, the other factors, especially welding heat input, to cause low crack arrest toughness was investigated for thick steel plate welds. EH grade steel plates were used in this study and 50 to 80 thick plates were tested to confirm thickness sensitivity. Electro gas welding (EGW) and flux cored arc welding (FCAW) were adopted to prepare the welded joints. Temperature gradient ESSO test was performed to measure $K_{ca}$ values with the variation of welding variables. As a result of this study, regardless of plate thickness, welding heat input to cause welding residual stress around crack path is a key factor to control the brittle crack propagation in welded joints.

• Journal of Biosystems Engineering
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• v.30 no.6 s.113
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• pp.333-339
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• 2005

The pesticide is raising public interest in the world, because it causes damage to an environmental pollution and the human health remaining agricultural products and an ecosystem, in spite of the advantages. Particularly, each country restricts the residual pesticide and induces observance about the safety and usage standard so that they can control the amount of pesticide used and defend the safety of agricultural products. The habitual practice for the analysis of the residual pesticide depends on GC (gas chromatography), HPLC (high performance liquid chromatography) and GC/MS (gas chromatography/mass spectroscopy), which triturate the fixed quantity of samples, abstract and purify as a suitable organic solvent. These methods have the highly efficient in aspects of sensitivity and accuracy. On the other hand, they need the high cost, time consuming, much effort, expensive equipment and the skillful management. Carbofuran is highly toxic by inhalation and ingestion and moderately toxic by dermal absorption. As with other carbamate compounds, it is metabolized in the liver and eventually excreted in the urine. The half-life of carbofuran on crops is about 4 days when applied to roots, and longer than 4 days if applied to the leaves. This research was conducted to develop immunoassay for detecting carbofuran residue quickly on the basis of surface plasmon resonance and to evaluate the measurement sensitivity. Gold chip used was CM5 spreaded dextran on the surface. An applied antibody to Immunoassay was GST (glutathione-s-transferase). The association and the dissociation time were 176 second and 215 second between GST and carbofuran. The total analysis time using surface plasmon resonance was 13 minutes including regeneration time, on the other hand HPLC and GC/MS was 2 hours usually. The minimum detection limit of a permissible amount for carbofuran in the country is 0.1 ppm. The immunoassay method using surface plasmon resonance was 0.002 ppm.

• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.21-29
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• 1999

The effects of density and pore size distribution of substrate in preparing SiC conversiton layer on graphite substrate were investigated. The chemical reaction for formation of SiC conversion layer was occurred at substrate surface or below surface through SiC gas infiltration. It was supposed that the pore size distribution required for the sufficient SiO gas infiltration and the continuous chemical reaction during conversion process was in the range of 1.0∼10.0$\mu\textrm{m}$. In the stress analysis of SiC layer with finite element method (FEM), the residual stress distribution due to thermal mismatch was shown. However, the compressive stress was measured in SiC layer by X-ray diffraction, it was presumed that the residual stress distribution of SiC layer was mainly influenced by the constraining effect of interlayer between SiC layer and graphite substrate, and the densification behaviro and the grain growth in SiC conversion layer.

• Analytical Science and Technology
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• v.13 no.1
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• pp.34-40
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• 2000

The optimum conditions for the half-life time and residual analysis of the iminoactadine triacetate fungicide on soils were investigated by using the gas chromatography. Iminoctadine triacetate(IOTA) was extracted from soils with 2.0 M-NaOH/methanol and chloroform. The extracted IOTA was derivatized to pyrimidine hexafluroacetylacetone by the acetylation and analyzed with GC/ECD after elimination of moisture and impurities on the Sep-Pak column. From the standard addition experiments with 0.1 and 1.0 ppm, the average recoveries were ranged from 83.8 to 93.2 % and the detection limit was 0.005 ppm. The half-life time of iminoctadine triacetate in the silty clay was 30 days in the laboratory and 19.5 days in the field test whereas it was 27 days and 17.5 days for each in case of silty loam.

• Korean Journal of Veterinary Research
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• v.17 no.2
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• pp.63-71
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• 1977

During the period of March, 1976 to December, 1976, 48 raw milk samples were taken from dairy cows at 48 different dairy farms in Korea analyzed by gas liquid chromatography to determine the seasonal variation of the amount of organochlorine pesticide residues. At the same time 80 market milk, 10 beef and 10 pork samples were analyed by the same procedure for checking residual levels. The results were summarized as follows; 1. Milk samples from 17 dairy farms (36 per cent of tatal) were shown to be contaminated with various organochlorine pesticides. The residua lrate of ${\gamma}-BHC$ in tested samples were 44per cent (14 sam ples) that of aldrine was 28 per cent (9 samples) and those of pp'-DDT, dieldrin and heptachlor were 9.3 percent (3 samples) respectively. 2. In raw milk pp'-DDT, ${\gamma}-BHC$, aldrin, dieldrin and heptachlor were detected, and aldrin, dieldrin and heptachlor were detected in the market milk. Any kinds of organochlorine pesticides were not detected in beef samples but dieldrin and heptachlor were detected in pork samples. Average residual values of aldrin, dieldrin and heptachlor in the market milk were 0.0077 ppm (0.0000~1.1100 ppm), 0.0001ppm (0.0000~0.0500 ppm) and 0.0008 ppm (0.0000~2.0520 ppm), respectively, and those of dieldrin and heptachlor in pork samples were 0.0010 ppm (0.0000~0.0100 ppm) and 0.0033 ppm (0.0000~0.0330 ppm). respectively. 3. Residues of organochlorine pesticides in raw milk were extremely variable; in fact pp'-DDT was detected in milk samples from A, B, C and D districts and endrin was not detected from all districts. The ${\gamma}-BHC$ and dieldrin were detected at the district of A, C and D, aldrin at the districts of A and C and heptachlor at the districts of both A and D. 4. Seasonal trends of residual values of organochlorine pesticides were, in general, noticeable. The residual level was much higher in Spring than in other seasons and showed the tendeney of decrease from spring through summer and autumn generally; in the case of pp'-DDT average residual values were 0.0121 ppm in spring, 0.0022 ppm in summer and not detected in autumn. But in winter ${\gamma}-BHC$ and aldrin residues were increased a little. Residual values in raw milk (when cow are fed on hay and silage) were appeared higher in winter than the other seasons. 5. Residues of organochlorine pesticides in raw milk were not related in respect to hygienic conditions of dairy farms pp'-DDT and heptachlor were, in general, detected in all farms and aldrin was more detected in milk from well sanitated farms than poor sanitated ones.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.169-174
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• 2006

A distinctive difference of hydrocarbon in crude oil and petroleum products exists. Depending on the origin where it comes from, crude oil shows its own unique pattern which is different from petroleum products containing characteristics according to their operating process and production period. A process of mixing behavior in a tank containing residual amounts of oil draws its own pattern when analysis is conducted. The analytical process described above is named oil fingerprint method. This study investigates an effectiveness of the method for comparing data sets produced by conventional gas chromatography with mass spectrometer (GC/MS) and comprehensive two-dimensional gas chromatography (GC X GC) which is known as powerful new technology for chemical analysis.

• Journal of Welding and Joining
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• v.26 no.3
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• pp.45-50
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• 2008

SM45C steel rods being used generally for power transmission shafts and machine components was selected and welded by Butt-GMAW(Gas Metal Arc Welding) method. An estimation of fatigue life was studied by constructing S-N curve. Fatigue strength of base metal zone showed higher values than one of weld zone in low cycles between $10^4$ and $10^6$cycles. However, significant decrease in fatigue strength of base metal was found around $10^6$cycles, which were almost same as one of heat affected zone. This decrease was attributed that initial residual stress of the steel rods distributed by drawing process was diminished by continually applied load, and resulted in softening of base metal. The fatigue limit of the weld zone was highest in the boundary between deposited metal zone and heat affected zone, and followed by in the order of deposited metal zone, base metal zone, and heat affected zone. Based on these results, it is revealed that the stress for safety design of machine components using SM45C butt-welded steel rods must be selected within the region of the lowest fatigue limit of heat affected zone.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.706-710
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• 2010

Understanding of chemical composition and energy contents in tree is important to develope strategies of renewable energy policy to cope with climate change. Residual biomass as renewable energy source was evaluated and focused on the bark-containing branches. Chemical analysis studies were conducted for different part of yellow poplar (Liriodendron tulipifera), which were partitioned to inner bark, outer bark, small branches, medium branches, big branches and trunk. The variations in hydrophobic extractives, hydrophilic extractives, lignin, carbohydrate compositions, energy contents (higher heating value) and the ash content were determined. The inner and outer bark had higher ash content, hydrophobic and hydrophilic extractives content, and higher energy content than those of tree trunk. Polysaccharides content in inner and outer bark was quite lower than those of stem or branches. Based on the energy content of residual biomass, replacement of fossil fuel and greenhouse gas emission abatement were calculated.