• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.92-95
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• 2002

A study on the system automation for the nitrogen splash slag coating in Basic Oxygen Blowing Furnace (BOF) is described. The engineers are trying to do their best efforts to increase the life of converter lining by developing improved refractory material and optimal operation techniques in the steel plants, A new slag coating method is needed to reduce the erosion rates of the refractory. In the current slag costing method, the BOF was swung back and forth. The new method uses the oxygen lance to blow the residual slag to the walls and cone of the converter. The nitrogen gas is used for blowing. This method is developed based on the automation process at factory in POSCO dated on the May 1998. The test results of nitrogen splash slag coating system for the BOF at POSCO are show to show the effectiveness of the system.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.31-35
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• 2001

Slopping deteriorates the productivity and the stability of operation in BOF refining process, and hence POSCO has developed methods to predict and prevent slopping. Specific equipment was developed to measure the change of the reacting force to the oxygen-blowing lance against oxygen jet and the force was gathered and analyzed with the flow rate of oxygen and the height of lance. From this study, it was found that the reacting force is strongly correlated to the slag foam height. Currently, the modeling of the relation of the slag foaming level and the vertically acted force to lance is being approached for predicting the slopping.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1755-1764
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• 2016

The application of Bacillus sp. in the biological control of plant soilborne diseases has been shown to be an environmentally friendly alternative to the use of chemical fungicides. In this study, the effects of bioorganic fertilizer (BOF) fortified with Bacillus amyloliquefaciens SQY 162 on the suppression of tomato bacterial wilt were investigated in pot experiments. The disease incidence of tomato wilt after the application of BOF was 65.18% and 41.62% lower at 10 and 20 days after transplantation, respectively, than in the control condition. BOF also promoted the plant growth. The SQY 162 populations efficiently colonized the tomato rhizosphere, which directly suppressed the number of Ralstonia solanacearum in the tomato rhizosphere soil. In the presence of BOF, the activities of defense-related enzymes in tomato were lower than in the presence of the control treatment, but the expression levels of the defense-related genes of the plants in the salicylic acid and jasmonic acid pathways were enhanced. It was also found that strain SQY 162 could secrete antibiotic surfactin, but not volatile organic compounds, to suppress Ralstonia. The strain could also produce plant growth promotion compounds such as siderophores and indole-3-acetic acid. Thus, owing to its innate multiple-functional traits and its broad biocontrol activities, we found that this antagonistic strain isolated from the tobacco rhizosphere could establish itself successfully in the tomato rhizosphere to control soilborne diseases.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.109-118
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• 2007

Recently, flash memory is used to store data in mobile computing devices such as PDAs, SmartCards, mobile phones and MP3 players. These devices need index structures like the B-tree to efficiently support some operations like insertion, deletion and search. The BFTL(B-tree Flash Translation Layer) technique was first introduced which is for implementing the B-tree on flash memory. Flash memory has characteristics that a write operation is more costly than a read operation and an overwrite operation is impossible. Therefore, the BFTL method focuses on minimizing the number of write operations resulting from building the B-tree. However, we indicate in this paper that there are many rooms of improving the performance of the I/O cost in building the B-tree using this method and it is not practical since it increases highly the usage of the SRAM memory storage. In this paper, we propose a BOF(the B-tree On Flash memory) approach for implementing the B-tree on flash memory efficiently. The core of this approach is to store index units belonging to the same B-tree node to the same sector on flash memory in case of the replacement of the buffer used to build the B-tree. In this paper, we show that our BOF technique outperforms the BFTL or other techniques.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.85-88
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• 2005

The properties of pcc using BOF-slag were investigated in order to use as fine aggregate, which has been made in the steel making process and stabilized by air-jet method. The fluidity of flesh concrete has been improved with the usage of BOF-slag and it should be noted that the air content goes up. The compressive strength of hardened concrete was reduced at weight fraction over 50$\%$ and Young's modulus tends toward the trivial change. Also, the flexural and tensile strengths were increased with the usage, especially, the rupture values were increased to 1.2 times at the weight fraction of 30$\%$.

• 대한생식의학회:학술대회논문집
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• 1996.11a
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• pp.61.1-61.1
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• 1996

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.240.2-240
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• 2003

• Resources Recycling
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• v.7 no.1
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• pp.50-56
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• 1998

Basic oxygen furnace @OF) slag. a by-pradud of thc iron and steelmaking industry produced in largc quantities in Korea, poszs a subslantial disposal challenge. The BOF slag used in this study was if3 CaCO, in total n e u ~ ~ pnowger and application of 7-8 Mgha' was needed to bring soil pH to 6.5 horn pH 5.0-5.5 m silly clay or clay loam sod wnlained about 10% orgaoic matter. A field assay was conducted to shldg whether BOP slag could bc used as a dolomitic k i n g agent for agricullural soils. Four slag rates (0, 4, 8, 12 Mgha-')were investigated for their effcfect on soil pmperti~, mineral concentralions in leaf tissues of rice and soybean, and yield of the crops. Slag application at 8 Mgha-' rate in paddy field increased pH, Ca Mg, P, Si and Fe wntenl in sail and rice yield by 4.3-14.25 depending an the soil type. h upland field the 8 Mghaf ratc increa3ed pH, Ca and Fe wntent m soil and soybean yield by 36.6%. Thus, BOF slag appears to be a useful liming mate&\ulcornerl for corrzch~gs oil acidity on both paddy and upland ficld soils and for innwing Ca, Mg, P, Si, and Fe wncenhation in plants.

• Korean Journal of Metals and Materials
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• v.56 no.11
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• pp.813-821
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• 2018

The basic oxygen furnace (BOF) steelmaking process in the steel industry is highly complicated, and subject to variations in raw material composition. During the BOF steelmaking process, it is essential to maintain the carbon content and the endpoint temperature at their set points in the liquid steel. This paper presents intelligent models used to estimate the endpoint temperature in the basic oxygen furnace (BOF) steelmaking process. An artificial neural network (ANN) model and a least-squares support vector machine (LSSVM) model are proposed and their estimation performance compared. The classical partial least-squares (PLS) method was also compared with the others. Results of the estimations using the ANN, LSSVM and PLS models were compared with the operation data, and the root-mean square error (RMSE) for each model was calculated to evaluate estimation performance. The RMSE of the LSSVM model 15.91, which turned out to be the best estimation. RMSE values for the ANN and PLS models were 17.24 and 21.31, respectively, indicating their relative estimation performance. The essential input parameters used in the models can be selected by sensitivity analysis. The RMSE for each model was calculated again after a sequential input selection process was used to remove insignificant input parameters. The RMSE of the LSSVM was then 13.21, which is better than the previous RMSE with all 16 parameters. The results show that LSSVM model using 13 input parameters can be utilized to calculate the required values for oxygen volume and coolant needed to optimally adjust the steel target temperature.

• Economic and Environmental Geology
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• v.55 no.4
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• pp.377-388
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• 2022

Laboratory-scale experiments were performed to identify the As removal mechanism of the residual slag generated after the mineral carbonation process. The residual slags were manufactured from the steelmaking slag (blast oxygen furnace slag: BOF) through direct and indirect carbonation process. RDBOF (residual BOF after the direct carbonation) and RIBOF (residual BOF after the indirect carbonation) showed different physicochemical-structural characteristics compared with raw BOF such as chemical-mineralogical properties, the pH level of leachate and forming micropores on the surface of the slag. In batch experiment, 0.1 g of residual slag was added to 10 mL of As-solution (initial concentration: 203.6 mg/L) titrated at various pH levels. The RDBOF showed 99.3% of As removal efficiency at initial pH 1, while it sharply decreased with the increase of initial pH. As the initial pH of solution decreased, the dissolution of carbonate minerals covering the surface was accelerated, increasing the exposed area of Fe-oxide and promoting the adsorption of As-oxyanions on the RDBOF surface. Whereas, the As removal efficiency of RIBOF increased with the increase of initial pH levels, and it reached up to 70% at initial pH 10. Considering the PZC (point of zero charge) of the RIBOF (pH 4.5), it was hardly expected that the electrical adsorption of As-oxyanion on surface of the RIBOF at initial pH of 4-10. Nevertheless it was observed that As-oxyanion was linked to the Fe-oxide on the RIBOF surface by the cation bridge effect of divalent cations such as Ca²⁺, Mn²⁺, and Fe²⁺. The surface of RIBOF became stronger negatively charged, the cation bridge effect was more strictly enforced, and more As can be fixed on the RIBOF surface. However, the Ca-products start to precipitate on the surface at pH 10-11 or higher and they even prevent the surface adsorption of As-oxyanion by Fe-oxide. The TCLP test was performed to evaluate the stability of As fixed on the surface of the residual slag after the batch experiment. Results supported that RDBOF and RIBOF firmly fixed As over the wide pH levels, by considering their As desorption rate of less than 2%. From the results of this study, it was proved that both residual slags can be used as an eco-friendly and low-cost As remover with high As removal efficiency and high stability and they also overcome the pH increase in solution, which is the disadvantage of existing steelmaking slag as an As remover.