• Resources Recycling
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• v.9 no.6
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• pp.36-44
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• 2000

Fly ash was composed of the unburned carbon and mineral particles. The former was able to attach on the bubbles, while the latter was not. Therefore, it was possible to separate the unburned carbon and the mineral from fly ash using the froth flotation process. This study was carried out to evaluate the separation efficiency as a function of the ny ash particle properties in the column flotation. Separation efficiency was analyzed for various size fraction of -38 fm,38~125 fm and 1125 W, and for various fly ash samples containing 7, 11, and 20 wt% unburned carbon. For the size fractions of -38 fm containing 7 wt% unburned carbon, separation efficiency was 86ft, whereas separation efficiency was found to be 74% for the size fraction of +125$\mu\textrm{m}$ containing 20 wt% unburned carbon. The results indicated that separation efficiency increased with the decrease in the particle size and the unburned carbon content of the fly ash.

• Journal of Korean Society of Forest Science
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• v.7 no.1
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• pp.8-18
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• 1968

This experiment is a comparative study of influence on the seedling in individual pH treatment of culture soil I. T-R ratio and growth 1. T-R ratio has almost similar tendency in its range according to tree species, but in individual treatment there were lots of differences. In the strong acidic and the strong alkali conditions T-R ratio was small. This means the seedling body is out of balance. 2. Where the resistance to H-ion was stronger, the growth of root-system, that is, the resistance of fine root was comparatively better. 3. The growth of root system was greatly influenced by pH, and in the condition of pH3, pH8, pH9, the growth was especially worse. 4. Ginkgo biloba, Pinus rigida and Pinus banksiana kept on growing in the strong acidic condition. 5. The growth season has higher pH of culture soil than the dormant season, and tree species which have strong resistance of acidic had better growth and had stronger resistance of draught in the acidic condition of culture soil ; especially, Pinus rigida and Pinus banksiana were worse in the alkali condition. II Seedling pH 1. According to the tree species, there were differences in seedling pH, and tree species, considred to be strong in resistance of draught, had been high in seedling pH. 2. Seedling pH of the growth season was higher than that of the dormant season. 3. Seedling pH was not significant in pH treatment of the culture soil.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.21-34
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• 2017

The ground penetrating radar (GPR) signal can be measured with different amplitudes according to the directivity, so the directivity of the antenna should be considered. The objective of this study is to investigate the directivity of antenna by analyzing the reflection characteristics of electromagnetic waves radiated from the antenna, and to evaluate effective range of angle that can inspect an abnormal area according to the directivity of antenna. For the measurement of the directivity, a circular metal bar is used as reflector and the signals are measured by changing the angle and the distance between reflector and antenna in the E- and H-plane. The boundary distance between the near field and the far field is determined by analyzing the amplitudes of reflected signals, and two points with different distances from each of near and far fields are designated to analyze radiation patterns in near and far fields. As a result of radiation pattern measurement, in the near field, minor lobes are observed at angle section at more than $50^{\circ}$ in both E- and H-plane. Therefore, antenna has the directivity for the direction of main lobe and minor lobes in near field. In the far field, antenna has the directivity for a single direction of main lobe because minor lobes are not observed. The amplitude of the signal reflected from the near field is unstable, but it can be distinguished from noise. Therefore, in the near field, the ground anomaly can be detected with high reliability. On the other hand, the amplitude of the signal reflected from the far field is stable, but it is hard to distinguish between reflected signal and noise because of the excessive loss of electromagnetic wave. The analyses of directivity in the near and the far fields performed in this study may be effectively used to improve the reliability of the analyses of abnormal area.

• Journal of Korean Home Economics Education Association
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• v.29 no.3
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• pp.15-32
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• 2017

This study investigated the effectiveness of home economics class on self-esteem and stress of middle school students. Data were collected from self-reported inventory of the middle school students in Y city of Gyeonggi province and 165 data copies were used for analyses. Data were analyzed for frequency, percentage, mean, standard deviation, Cronbach's ${\alpha}$, t-test, corelation and dependent t-test using SPSS/PC 18.0 program. The results were as follows. First, the average of positive self-esteem was 2.74 and that of negative self-esteem was 1.90 on a 4 Likert scale. The range of stress level was 1.88~2.48 on a 5 Likert scale. Life satisfaction was 3.90 and helpfulness of home economics class was 3.89 on a 5 point Likert scale, which means moderately high. Second, examining differences in variables according to gender, there were statistically significant differences in stress regarding family for both pre- and post-tests. Third, helpfulness of home economics class had positive correlation with positive self-esteem and life satisfaction and had negative correlation with negative self-esteem and stress, which means that home economics class enhance life satisfaction and positive self-esteem and lessen negative self-esteem and stress of middle students. Fourth, as a result of comparison of pre and post-tests, positive self-esteem, life satisfaction, and helpfulness of home economics class increased statistically after home economics classes, while stress regarding school life decreased statistically. Even though students' growth and changes resulting from learning other subjects were not controlled, it was meaningful that effectiveness of home economics class were examined and helpful information for enhancing perception of home economics education were provided.

• Journal of Yeungnam Medical Science
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• v.6 no.1
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• pp.59-68
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• 1989

Ceftizoxime sodium is a new synthetic ${\beta}$-lactam antibiotic combining potent antibacterial activity with high stability to a wide range of bacterial ${\beta}$-lactamase. This experiment was achieved to evaluate the antibacterial activities of ceftizoxime sodium againist Gram negative enteric bacteria isolated from in outpatient visiting Yeungnam university hospital and to study the emergence of drug induced bacterial varients which resist to ceftizoxime in vitro. The antibacterial activity of the ceftizoxime was compared with that of antibiotics and its effect on population of normal intestinal flora in mice was observed. The results are summarized as follows : 1. Highly effective antibacterial activity of ceftizoxime against Gram negative enteric bacilli was demonstrated and this antibacterial activity was superior to that of ampicillin. 2. Several test strains shows multiple antibiotic resistence. Among 15 strains of Escherichia coli, 1 strain was resistent to ampicillin, cefadroxyl, gentamicin, tetracycline, and 2 strains were resistent to ampicillin, cefadroxyl, tetracycline, five strains of Escherichia coli and Enterobacter cloacae was resistent to amplicillin, tetracycline and Shigella dysenteria was resistent to ampicillin, gentamicin, tetracycline. 3. The frequency of in vitro emergence of resistent varients among ceftizoxime sensitive bacteria in the presence of increasing concentrations of the compound was found to be low. 4. Plasmid was isolated in 6 of 9 strains (6 strains of Escherichia coli, Shigella dysenteriae, Enterobacter cloaceae and Salmonella typhi) That showed different antibiotic resistance. They were 5 strains of Escherichia coli and 1 strain of Shigella dysenteriae. However, plasmid could not be considered as a hallmark for antibiotic resistance by this. Further studies with curing experiment are to be accomplished for this purpose. 5. Changes in the bacterial count of normal intestinal flora following 25mg/kg/day administration of ceftizoxime over S consecutive days were not significant. In conclusion, ceftizoxime appeared to be a drug of choice in the treatment of Gram negative enteric bacilli infection.

• Journal of the Geological Society of Korea
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• v.54 no.5
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• pp.477-488
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• 2018

Fluid muds commonly occur in estuarine environments, but their ancient examples have rarely been studied in terms of depositional characteristics and processes. Cores of estuarine channel deposits of the Early Cretaceous McMurray Formation, Alberta, Canada show various mudstone layers that possess depositional characteristics of high clay-concentration flows. These mudstone layers are examined in detail through microscopic observation of thin sections and classified into three microfacies (<1 to 25 mm thick) on the basis of sedimentary texture and structures. Structureless mudstone (Microfacies 1) consists mainly of clay particles and contains randomly dispersed coarser grains (coarse silt to fine sand). This microfacies is interpreted as being deposited by cohesive mud flows, i.e., fluid muds, which possessed sufficient strength to support suspended coarser grains (quasi-laminar plug flow). Silt-streaked mudstone (Microfacies 2) mainly comprises mudstone with dispersed coarse grains and includes very thin, discontinuous silt streaks of coarse-silt to very-fine-sand grains. The texture similar to Microfacies 1 indicates that Microfacies 2 was also deposited by cohesive fluid muds. The silt streaks are, however, suggestive of the presence of intermittent weak turbulence under the plug (upper transitional plug flow). Heterolithic laminated mudstone (Microfacies 3) is characterized by alternation of relatively thick silt laminae and much thinner clay laminae. It is either parallel-laminated or low-angle cross-laminated, occasionally showing low-amplitude ripple forms. The heterolithic laminae are interpreted as the results of shear sorting in the basal turbulent zone under a cohesive plug. They may represent low-amplitude bed-waves formed under lower transitional plug flows. These three microfacies reflect a range of flow phases of fluid muds, which change with flow velocities and suspended mud concentrations. The results of this study provide important knowledge to recognize fluid-mud deposits in ancient sequences and to better understand depositional processes of mudstones.

• Food Engineering Progress
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• v.13 no.3
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• pp.195-202
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• 2009

This study was accomplished that analysis of seven polycyclic aromatic hydrocarbons (PAHs) in smoked or nonsmoked processing foods by high performance liquid chromatography (HPLC) with fluorescence detection. The calibration line was constructed with injected different levels of standard concentration. Limit of detection (LOD) and limit of quantification(LOQ) showed higher linearity ($r^{2}$=0.998) reasonably, and recovery exhibited 0.033-0.666 $\mu$g/kg, 0.108-2.217 $\mu$g/kg and 69.31-90.14%, respectively. As a result, the samples using smoked tuna as smoked materials contained seven PAHs with different range from 0.256 to 0.486 $\mu$g/kg. The benzo[a]pyrene, indicator of PAHs, was detected to below the LOQ in two samples. Concentrations of benzo[a]pyrene in three samples were below the 2 $\mu$g/kg which is the limit of regulation. Smoked tuna sauces were detected from 0.321 to 0.552 $\mu$g/kg and not detected in drying powders. PAHs of smoked meat products were ranged from 0.720 to 2.027 $\mu$g/kg and are higher than concentration of tuna smoked samples. PAHs were very low in non-smoked foods including mustard, herb, and roasted meats.

• Korean Journal of Remote Sensing
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• v.14 no.4
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• pp.353-365
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• 1998

Light absorption coefficient per unit mass of particles, i.e., specific absorption coefficient, is important as one of the main parameters in developing algorithms for ocean color remote sensing. Specific absorption coefficient of chlorophyll ($a^*_{ph}$) and suspended sediment ($a^*_{ss}$) were analyzed with a spectrophotometer using the "wet filter technique" and "Kishino method" for the seawater collected in the Yellow and Mediterranean Sea. An improved data-recovery method for the filter technique was also developed using spectrum slopes. This method recovered the baselines of spectrum that were often altered in the original methods. High $a^*_{ph}({lambda})$ values in the oligotrophic Mediterranean Sea and low values in the Yellow Sea were observed, ranging 0.01 to 0.12 $m^2$/mg at the chlorophyll maximum absorption wavelength of 440 nm. The empirical relationship between $a^*_{ph}$(440nm) and chlorophyll concentrations () was found to fit a power function ($a^*_{ph}$=0.039 $^{-0.369}$), which was similar to Bricaud et al. (1995). Absorption specific coefficients for suspended sediment ($a^*_{ss}$) did not show any relationship with concentrations of suspended sediment. However, an average value of $a^*_{ss}$ ranging 0.005 - 0.08 $m^2$/g at 440nm, was comparable to the specific absorption coefficient of soil (loess) measured by Ahn (1990). The morepronounced variability of $a^*_{ss}$ than $a^*_{ph}$ was determined from the variable mixing ratio values between particulate organic matter and mineral. It can also be explained by a wide size-distribution range for SS which were determined by their specific gravity, bottom state, depth and agitation of water mass by wind in the sea surface.

• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.213-222
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• 1998

Electro-Optical Camera(EOC) is the main payload of the KOrea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including a Digital Terrain Elevation Map(DTEM). This instalment which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510~730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response, the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the users of EOC data. The modulation transfer function of EOC was measured as greater than 16 % at Nyquist frequency over the entire field of view, which exceeds its requirement of larger than 10 %. The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.461-470
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• 2019

This study was carried out to quantify the drought stress in grafted watermelon seedlings non-destructively by using chlorophyll fluorescence (CF) imaging technique rather than the visual judgment. Six-day old watermelon seedlings were grown under uniform irrigation for 3 days, and then given drought stress. Afterward, the sensor for the measurement of water content in plug tray cell unit was used to classify the drought-stress level into nine groups from D1 (53.0%, sufficient moisture state) to D9 (15.7%, extremely dry stress), and the 16 CF parameters were measured. In addition, re-irrigation was performed on the drought stressed seedlings(D5 - D9) to determine the growth and photosynthesis recovery level, which was not confirmed by visual judgment. The kinetic curve patterns of CF in three different drought stressed seedling groups were found to be different for the early detection of drought stress. All the 16 CF parameters decreased continuously with exposure to drought stress and drastically decreased from D5 (32.1%) where the visual judgment was possible. The fluorescence decline ratio (Rfd_Lss) started to decrease from the initial drought stress level (D5 - D6), and the Maximum PSII quantum yield (Fv/Fm) was significantly decreased in the later extreme drought stress range (D7 - D9) by re-irrigation recovery test. Thus, Rfd_Lss and Fv/Fm parameters were finally selected as potent indicators of growth and photosynthesis recovery in the initial and later stages of drought stress. Also, to the differences in the numerical values of the individual chlorophyll fluorescence parameters, the drought stress level was intuitively confirmed through the image. These results indicate that Rfd and Fv/Fm can be considered as potential CF parameters for the detection of low and extremely high drought stress, respectively. Furthermore, Fv/Fm can be considered as the best CF parameters for recovery at re-irrigation.