• Journal of Ocean Engineering and Technology
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• v.10 no.3
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• pp.138-152
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• 1996

Many studies of heat transfer on the swirling flow or unswirled flow in a abrupt pipe expansion are widely carried out. The mechanism is not fully found evidently due to the instabilities of flow in a sudden change of the shape and appearance of turbulent shear layers in a recirculation region and secondary vortex near the corner. The purpose of this study is to obtain data through an experimental study of the swirling flow and heat transfer downstream of an abrupt expansion in a circular pipe with uniform heat flux. Experiments were carried out for the turbulent flow nd heat transfer downstream of an abrupt circular pipe expansion. The uniform heat flux condition was imposed to the downstream of the abrupt expansion by using an electrically heated pipe. Experimental data are presented for local heat transfer rates and local axial velocities in the tube downstream of an abrupt 3:1 & 2:1 expansion. Air was used as the working fluid in the upstream tube, the Reynolds number was varied from 60, 00 to 120, 000 and the swirl number range (based on the swirl chamber geometry, i.e. L/d ratio) in which the experiments were conducted were L/d=0, 8 and 16. Axial velocity increased rapidly at r/R=0.35 in the abrupt concentric expansion turbulent flow through the test tube in unswirled flow. It showed that with increasing axial distance the highest axial velocities move toward the tube wall in the case of the swirling flow abrupt expansion. A uniform wall heat flux boundary condition was employed, which resulted in wall-to-bulk temperatures ranging from 24.deg. C to 71.deg. C. In swirling flow, the wall temperature showed a greater increase at L/d=16 than any other L/d. The bulk temperature showed a minimum value at the pipe inlet, it also exhibited a linear increase with axial distance along the pipe. As swirl intensity increased, the location of peak Nu numbers was observed to shift from 4 to 1 step heights downstream of the expansion. This upstream movement of the maximum Nusselt number was accompanied by an increase in its magnitude from 2.2 to 8.8 times larger than fully developed tube flow values.

• Journal of Nutrition and Health
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• v.13 no.1
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• pp.51-58
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• 1980

In order to investigate the level of pesticide residues in the vegetables for Kimchi materials (Chinese cabbage, radish, red pepper, garlic and cucumber), which were produced in Andong district, organochlorine and organophosphur pesticide residues were analyzed using gas chromatography. The results were as follows; 1) In chinese cabbage, radish and some other vegetables harvested in early summer (June), organochlorine and organophosphur pesticide residues were detected in almost all of the samples tested, and a few of them showed a level higher than the organochlor APR(allowable pesticide residues). 2) Heptachlor, the soil insecticide was the most abundantly detected pesticide among the four organochlorine pesticides tested (Dieldrin, Endrin, BHC, Heptachlor) in this study. 3) Somewhat higher concentrations of organochlorine pesticides were detected in all kinds of sample vegetables harvested in late summer than in those harvested in early summer. And the frequency of organochlorine pesticide contamination was also increased, but the frequency of organophosphur pesticide contamination was decreased. 4) In the vegetable harvested in late autumn, level of organochlorine pesticide residues and frequency of contamination were markedly decreased and organophosphur pesticide residues (Diaginon, Malathion, Thiometon, EPN) were rarely detected. 5) The results of this study indicates that to take a lot of vegitables grown in summer was somewhat uncomfortable than those grown in autumn.

• Journal of Bio-Environment Control
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• v.17 no.1
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• pp.1-8
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• 2008

Four cover plants such as Phlox subulata, Glechoma hederacea var. longituba, Sedum middendorffianum and Saxifraga laciniata were evaluated to investigate the effect of companion planting on reducing soil erosion in Chinese cabbage cultivated highland. The experiment was conducted using lysimeters of $5\;m{\times}2\;m$ (length$\times$width) with 5, 15 and 30% slopes. Companion plants except Sedum middendorffianum did not interface with growth of Chinese cabbage Glechoma hederacea var. longituba and Sedum middendorffianum grew faster than Phlox subulata and Saxifraga laciniata in the early growth stage suer transplanting, resulting in fast ground covering, but the ground covering by Phlox subulata and Saxifraga laciniata was delayed because growth suppression by high air temperature during summer season. Soil erosion became severe as increasing degree of slope. Assessments of the four cover plants were conducted in relation to soil conservation characteristic of scenery, endurance to the environment stress, plant growth and weed suppression. From the assessments, Phlox subulata was superior to other intercropping crops tested for reducing soil erosion in highland cultivation of Chinese cabbage.

• Journal of the Korean Society for information Management
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• v.34 no.3
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• pp.89-107
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• 2017

This study aims to compare information seeking behavior of 1300K users on PC and mobile phone. Transaction logs of 1300K, a major Korean shopping search engine, were analyzed. These transaction logs were collected over 1 month period, from April 1 to April 31, 2016. The results of this study show that there are a little more mobile sessions than PC sessions. Users conducted slightly more browsing on PCs than mobile phones, whereas users submitted queries more than two times on mobile phones than on PCs. Users clicked more search results on PCs than mobile phones, whereas users made important decision makings such as product purchases more on mobile phones than PCs. Top queries and categories were similar between PCs and mobile phones. Queries and categories on mobile phones were more focused than queries on PCs. Overall, mobile search behavior is more simple, passive, and focused than PC search behavior. The results of this study can be implemented to the effective improvement and development of search services for different devices.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.135-142
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• 1990

The quality improvement of antigen (crude saline extract) of Spirometra maptscni 1)lerocercoid (sparganum) was investigated by protein purificatioll. The crude extract was fractionated by gel filtration through Sephacryl S-300 Superfine. Its third fraction was purified by affinity chromatography using a monoclonal antibody as ligand. When observed by SDS-PAGE, the purified protein was composed of 2 bands of 36 kDa and 29 kDa which were found already as the most sensitive components in the crude extract by immunoblots with patients sera. The quality of the purified antigen was evaluated in comparison with the crude extract by ensyme-linked imnunosorbent assay (ELISA) for the specific (IgG) antibody in sera of human sparganosis, other parasitic and neurologic diseases, and normal control. When the purified antigen was used: the sensitivity was not altered but remained high (96.4%) while the specificity was increased from 86.8% to 96.9%.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.347-355
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• 2006

Possible nematicidal effects of plant extracts of 25 species uninfected by M. hapla were observed at the 5 times dilutions in all treatments and at the 10 times dilutions in Anemarrhena asphodeloides, Acorus calamus, Achyranthes japonica, Agrimonia pilosa, Dianthus chinensis, Geum aleppicum, Houttuynia cordate, Rudbeckia bicolor, Ricinus communis, Scrophularia buergeriana, Sesamum iindicum, Sedum kamtschaticum, and Sanguisorba officinalis. The 13 species plant extracts of 5 times dilutions were evaluated for the suppression effects on reducing densities of M. hapla by treating to C. lanceolata sown and transplanted later in pots. All the plant extracts showed suppressive effects on M. hapla except for.A. pilosa. The suppressive effects of A. asphodeloides, A. japonica, A. calamus, D. chinensis, R. communis, and S. buergeriana were over 80%. When the selected plants had been incorporated into the soil before C. lanceolata was sown, the numbers of root galls, egg sacs and $J_{2}$ appeared lower in the treatment of 12 plant species than in control except for S. indicum. But the suppressive effects were lower than the effects of selected plants being cultivated simultaneously in the field. A. calamus and A. japonica exhibited over 70% suppressive effects, among the tested plants.

• Journal of Korean Society of Transportation
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• v.18 no.6
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• pp.63-75
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• 2000

Stated Preference (SP) data has been regarded as more useful than Revealed Preference (RP) data, because researchers can investigate the respondents\` Preference and attitude for a traffic condition or a new traffic system by using the SP data. However, the SP data has two bias: the first one is the bias inherent in SP data and the latter one is the attrition bias in SP panel data. If the biases do not corrected, the choice model using SP data may predict a erroneous future demand. In this Paper, six route choice models are constructed to deal with the SP biases, and. these six models are classified into cross-sectional models (model I∼IH) and dynamic models (model IV∼VI) From the six models. some remarkable results are obtained. The cross-sectional model that incorporate RP choice results of responders with SP cross-sectional model can correct the biases inherent in SP data, and also the dynamic models can consider the temporal variations of the effectiveness of state dependence in SP responses by assuming a simple exponential function of the state dependence. WESML method that use the estimated attrition probability is also adopted to correct the attrition bias in SP Panel data. The results can be contributed to the dynamic modeling of SP Panel data and also useful to predict more exact demand.

• Journal of Korean Society of Forest Science
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• v.81 no.1
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• pp.21-29
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• 1992

This study was conducted to provide basic information for deciding silvicultural system appropriate to a natural mixed stand in Jindong-Ri. For this, the stand structure such as DBH distribution, height distribution, and volume per DBH class were analyzed and the possibility of selection cutting as a silvicultural system was discussed. The DBH structure of the stand has reverse J-shaped diameter distribution which is typical in a selection cutting stand. The possibility of selection cutting is also accepted in the height structure by showing multi-storied height distribution of the stand. On the other hand, volume structure per DBH class did not show the mature stand of selection cutting due mainly to the lack of number of trees at 30cm DBH class and above. It seems that the unclear part of stand structure should be solved by further studies. Also, the rate of increment for DBH and volume should be estimated to predict the future stand structure.

• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.16-21
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• 1984

The present study was aimed to investigate persistence of dichlorvos EC, fenitrothion EC, fenthion EC, and phenthoate EC in and on mulberry leaves with special reference to silkworm mortality and cocoon production under greenhouse condition. The halflives of fenitrothion, fenthion, and phenthoate in and on mulberry leaves were ranged from two to three days, while that of dichlorvos was less than 9 hours. The insecticide residues in and on mulberry leaves persisted longer in spring cropping season than in autumn cropping season. Elapsed periods from last application of each insecticide to leaf harvest for silkworm feed and maximum residue limits for safe cocoon production as well as relations between insecticide residues in and on mulberry leaves and silkworm mortality were produced.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.404-411
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• 2011

The purpose of this study was to analyze the characteristics of plant covering in the extensive green roof site. Eighteen herbaceous perennial grass such as Caryopteris incara and sedum species such as Sedum Kamtschaticum were planted on an experimental green roof with 10cm substrate depth in 2007. This study investigated vegetation change over 3 growing seasons 2007-2009. The covering rates of planted species mostly increased in 2008, but declined in 2009 except 6 species such as sedum specis and Thymus quinquecostatus var. japonica etc. There were four categories of covering characteristics generated from the results of this study. These include the type of sustain planting site, the type of encroach adjacent site, the type of creeps and spreads, and the type of scatters and spreads. The covering models of eight planted species were drawn by simple regression analysis. However more monitoring of various plants will be needed to establish the information for sustainable roof planting plan.