• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.418-422
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• 1999

A method is described for the selective determination of Cr(III) and Cr(VI) in aqueous solutios by flame atomic absorption spectrometry. Selective extraction of $Cr_2O_7^{2-}$ was performed by Aliquat 336/NIBK from the mixtures of $Cr^{3+}$ and $Cr_2O_7^{2-}$, and the extraction of $Cr^{3+}$ was followed after complex formation with citrate by using the same extractant. The concentraction of each analyte in the extract was determined by $N_2O-C_2H_2$ flame atomic absorption spectrometry. The recoveries of $Cr^{3+}$ and $Cr_2O_7^{2-}$ from 50mL of aqueous solution ranging 0.1~1.0 ${\mu}g/mL$ as Cr respectively by single extractions with 5 mL of 1%(V/V) Aliquat 336/MIBK were resulted as 98.8∼101.7%.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.281-289
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• 2000

While acquiring images, the relative motion between the imaging device and the object scene seriously damages the image quality. This phenomenon is called motion blur. The peak-trace approach, which is our recent previous work, identifies important parameters to characterize the point spread function (PSF) of the blur, given only the blurred image itself. With the peak-trace approach the direction of the motion blur can be extracted regardless of the noise corruption and does not need much Processing time. In this paper stochastic peak-trace approaches are introduced. The erroneous data can be selected through the ML classification, and can be made small through weighting. Therefore the distortion of the direction in the low frequency region can be prevented. Using the linear prediction method, the irregular data are prohibited from being selected as the peak point. The detection of the second peak using the proposed moving average least mean (MALM) method is used in the Identification of the motion extent. The MALM method itself includes a noise removal process, so it is possible to extract the parameters even an environment of heavy noise. In the experiment, we could efficiently restore the degraded image using the information obtained by the proposed algorithm.

• Journal of Korean Home Economics Education Association
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• v.21 no.2
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• pp.61-81
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• 2009

The purpose of this study was to develop Graphic Organizer as Advance Organizer. The 'Menu Planning and Food Selection' unit of second grade middle school Technology & Home Economics(revised curriculum of 2007) was selected as the study subject. The course of abstracting an essential education element got done $3^{rd}$ times. It abstracted the first essential education elements to analyze the presented sentence or a concept with the educational contents factor which is on the achievement standard of the area of dietary life from 5grade to 10grade in curriculum revised in 2007. The first 4 essential education elements selected were superiority and cultural value of Korean traditional meal, preparing a balanced diet for the family, food purchasing, and food selection based on the various information'. It abstracted second essential education elements that it concretized the first content factor on a unit of this study and solved overlapping when it was happened at the first contents factor and made connecting with between grade. The $3^{rd}$ essential education elements abstracted to classify the contents which abstracted essential education elements in second. And, it developed Graphic Organizer on a unit of 'Menu Planning and Food Selection' in eight-grade Technology & Home Economics based on the abstracted essential education elements. Graphic Organizer was developed in according to order of the way for making on a Concept Map of Heo In Sook(2000). Developed Graphic Organizer is all of 10 which are 'nutrition value on food of the season', 'harmony and combination of food', 'natural dressing and a garnish', 'the recipe', 'fermented food', 'a traditional instrument and a vessel', 'actor of food harm', 'present food', 'food quality certification' and 'selecting food with food information'.

• Analytical Science and Technology
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• v.19 no.5
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• pp.441-448
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• 2006

11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THCCOOH) is the major metabolite of tetrahydrocannabinol (THC) which is the primary psychoactive component of marijuana. It is also the target analyte for the discrimination marijuana use. A method using solid-phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) was developed for the determination of THCCOOH in human urine. Urine samples (3 mL) were extracted by SPE column with a cation exchange cartridge after basic hydrolysis. The eluents were then evaporated, derivatized, and injected into the GC/MS. The limits of detection (LOD) and quantitation (LOQ) were 0.4 and 1.2 ng/mL, respectively. The response was linear with a correlation coefficient of 0.999 within the concentration range of 1.2 (LLE 1.3)~50.0 ng/mL. The precision and accuracy were stable within 1.20% and the recovery was 83.6~90.7%. The recovery of SPE method was lower than that of liquid-liquid extraction (LLE), but there were no apparent differences in LOD, LOQ, precision and accuracy between the two methods. While SPE method is used as a very effective and rapid procedure for sample pretreatment, and clean extracts, LLE method was not suitable for the extraction procedure of THCCOOH in urine. The applicability of the method was proven by analyzing a urine samples from a marijuana abusers.

• Journal of The Korean Association For Science Education
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• v.38 no.1
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• pp.43-55
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• 2018

In this study, we investigated high school students' analogy generating processes using the think-aloud method. Twelve high school students in Seoul participated in this study. The students were asked to generate analogies on ionic bonding and were also interviewed after their activities. Their activities and interviews were recorded and videotaped. After classifying the analogy generating processes into the three stages-encoding, exploring sources, and mapping, several process components were identified. The analyses of the results indicated that they checked the target concept given and selected one for a salient attribute among many attributes of the target concept at the stage of encoding. After selecting the salient attribute, they translated the salient attribute that is a scientific term into an everyday term, which is named as 'extracting salient similarities.' At the stage of exploring sources, they chose the sources based on salient similarities and chose the final source through circular processes, which included the process components of 'evaluating the sources' and 'discarding the sources.' At the final stage, they added the attributes to analogs and mapping them to the attributes of the target concept, which is named as 'mapping shared attributes.' There were some cases that 'mapping shared attributes' appeared after they specified the situation of analogs or assumed new situation, which is named as 'specifying the situations.' Some students recognized unshared attributes in their analogs.

• Korean Journal of Optics and Photonics
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• v.18 no.3
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• pp.179-184
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• 2007

In order to extract more accurate skin parameters, this study was focused on the improvement of the efficiency of a previous inverse fitting algorithm based on genetic algorithms. The algorithm provides the best fitting result of the diffusion approximation model to a VRS (visual reflectance spectroscopy) curve of skin. Simplex and wavelength selection methods were applied to the previous algorithm. Nine skin parameters were inversely extracted from the modeling studies. The revised inverse fitting algorithm was determined to produce an 83% reduction of computation time and a 0.64% reduction of sum of square error, compared to the previous algorithm. In conclusion, we confirmed that the new algorithm provides faster and more accurate solutions for the diffusion approximation model.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.723-730
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• 2014

The usage of Ground Granulated Blast Furnance Slag (GGBFS) has been increased recently. Studies on the cement hydration model incorporating GGBFS as well as the properties of cement paste done with GGBFS such as compressive strength, hydration products and hydration heat have been the subjects of many researches. However, studies on the reaction degree of GGBFS that affect the properties of cement paste incorporating GGBFS are lacking globally and specially in Korea. Thus, in this study, the reaction degree of GGBFS using the method if selective dissolution, compressive strength, the amount of chemical bound water and $Ca(OH)_2$ were measured and analysed in accordance with water-binder ratio, replacement ratio of GGBFS, and curing temperature. The results show that the reaction degree of GGBFS, the amount of chemical bound water and $Ca(OH)_2$ in cement paste with GGBFS were higher in conditions where the replacement ratio of GGBFS was low and both water-binder ratio and curing temperature were high. Finally, the reaction degree of GGBFS was achieved at a value between 0.3~0.4.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.47-55
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• 2006

Recovery of acids from the waste etching solution of containing nitric, hydrofluoric and acetic acid discharged from silicon wafer manufacturing process has been attempted by using solvent extraction method. With EHA (2-Ethylhexlalcohol) for acetic acid and TBP(Tri-butly Phosphate) for nitic and hydrofluoric acid as extraction agent was carried on experiment to obtain the process design data in separation procedure. From the McCabe-Thiele diagram analysis, we obtained the optimum conditions of phase ratio(O/A) and stages to separate the each acid sequently from the mixture acids. The recovery yield was obtained 90% above for acetic acid from the acid mixtures, 90% above for nitric acid from acetic acid extraction raffinate and then 67% above for hydrofluoric acid from final extraction raffinate.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.27-34
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• 2010

This paper presents a methodology for classifying left and right motor imagery using a neural network with weighted fuzzy membership functions (NEWFM) and wavelet-based feature extraction. Wavelet coefficients are extracted from electroencephalogram(EEG) signal by wavelet transforms in the first step. In the second step, sixty numbers of initial features are extracted from wavelet coefficients by the frequency distribution and the amount of variability in frequency distribution. The distributed non-overlap area measurement method selects the minimized number of features by removing the worst input features one by one, and then minimized six numbers of features are selected with the highest performance result. The proposed methodology shows that accuracy rate is 86.43% with six numbers of features.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.789-795
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• 2014

Acetic acid is the most abundant and serious ethanol fermentation inhibitor in dilute-acid hemicellulosic hydrolysates. A mixture of xylose, acetic acid and sulfuric acid was chosen as a simulated hemicellulosic hydrolysate so as to find an optimal separation system to selectively remove acetic acid from the hydrolysates. In order to attain the purpose, emulsion liquid membrane was applied to removal of acetic acid from the simulated hemicellulosic hydrolysate. The effects of main constituents of water-in-oil (W/O) emulsion, such as amine extractant type, surfactant composition, additive type, and type and concentration of stripping agent, on extraction of acetic acid, xylose, and sulfuric acid in the simulated hemicellulosic hydrolysate were investigated. Under specific experimental conditions, degree of extraction of acetic acid was higher than 95% while loss of xylose was insignificant, which means that the current emulsion liquid membrane can be an economically feasible process.