• Korean Journal of Weed Science
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• v.12 no.4
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• pp.317-334
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• 1992

Weed flora and floristic composition were reviewed in lowland rice field and upland crop area. For lowland rice field weed flora was not much changed since 1971. About 29 weed species belonged to 18 families were occurred. However, floristic composition of dominant weed species has greatly changed mainly due to introduction of herbicides. The predominant weed species in 1971 when herbicide was not used were Rotala indica, Eleocharis acicularis, Monochoria vaginalis, Echinochloa crus-galli, while these for in 1991 were Eleocharis kuroguwai, Sagittaria pygmaea, S. trifolia, Echinochloa crus-galli and M, vaginalis, respectively. In 1981 weed survey, E. crus-galli was no longer troblesome weed. However, this species became important again thereafter by introduction of herbicide mixtures with pyrazolate, bensulfuron-methyl or pyrazosulfuronethyl. For upland crop area, 216 weed species belonged to 46 families were recorded. One hundred and sixtyfive of these were grown in winter crop area while 189 weed species occurred in summer crop area, respectively. Among these, 138 weed species were grown in both crop seasons. In general, summer crops had less number of weed species compared to winter crops. Even though the dominant weed species varied by crop the most common weeds were Chenopodium album, Alopecunrs aqualis, Stellaria alsine and S, media for winter crops and Digitaria sanguinalis, Portulaca oleracea, Chenopodium album and Acalypha australis for summer crops, respectively.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.296-305
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• 2006

The heterogeneity of crop transpiration is important to clearly understand the microclimate mechanisms and to efficiently handle the water resource in greenhouses. A computational fluid dynamic program (Fluent CFD version 6.2) was developed to study the internal climate and crop transpiration distributions of greenhouses. Additionally, the global solar radiation model and a crop heat exchange model were programmed together. Those models programmed using $C^{++}$ software were connected to the CFD main module using the user define function (UDF) technology. For the developed CFD validity, a field experiment was conducted at a $17{\times}6 m^2$ plastic-covered mechanically ventilated single-span greenhouse located at Pusan in Korea. The CFD internal distributions of air temperature, relative humidity, and air velocity at 1m height were validated against the experimental results. The CFD computed results were in close agreement with the measured distributions of the air temperature, relative humidity, and air velocity along the greenhouse. The averaged errors of their CFD computed results were 2.2%,2.1%, and 7.7%, respectively.

• Journal of Preventive Medicine and Public Health
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• v.23 no.4 s.32
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• pp.391-403
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• 1990

In order to assess the degree of atmospheric pollution and noise and to contribute the health improvement of residents in Pusan, the author measured the levels of CO, $SO_2,\;NO_2$, TSP, HCHO and noise in 8 areas (industrial, residential and park areas) from January to March in 1990. The results were as follows : 1. Sasang industrial area was significantly higher($2.85{\pm}0.84ppm$) in the average concentration of CO than other areas. However, there no areas to affect the human body in terms of CO concentration. 2. In general, industrial area was significantly higher ($0.134{\pm}0.084ppm$) in the average concentration of $SO_2$ than other areas, and it was the lowest ($0.009{\pm}0.005ppm$) in the Namchon-dong area. 3. Industrial ($0.033{\pm}0.009ppm$) and residential area ($0.029{\pm}0.004ppm$) were significantly higher in the average concentration of $NO_2$ than Park area ($0.009{\pm}0.001ppm$). However, there were no areas to affect the human body in terms of $NO_2$ concentration. 4. Sasang industrial area was the highest ($580.4{\pm}415.26{\mu}g/m^3$) at the average concentration of TSP and Hae-Un Dae area was the lowest ($97.22{\pm}37.86{\mu}g/m^3$). But TSP concentration showed the level to affect the human body in most areas. 5. Industrial area was significantly higher ($2.25{\pm}1.15ppb$) in the average concentration of HCHO than residential ($1.13{\pm}0.25ppb$) and park area ($1.33{\pm}0.20ppb$). 6. Industrial area was significantly higher ($77.28{\pm}6.92dB(A)$) in the level of noise than residential ($65.77{\pm}3.76dB(A)$) and park area ($64.65{\pm}5.25dB(A)$). In comparison with regional Standard Noise Level, howeverm the average noise level of residential and park area was higher than that of the Standard. In general, the level of pollution of industrial complex areas was relatively higher than those of residential and park areas. Among the industrial areas, sasang area was worst in most items. Both $SO_2$ and TSP showed the level to affect the human body in most of studied areas. It is necessary to install a new Air Quality Standard for HCHO to screen our environmental pollution.

• Korean journal of food and cookery science
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• v.27 no.3
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• pp.11-20
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• 2011

The purpose of this study was to investigate the use and perception of adults concerning bokbunja (Rubus coreanus Miquel) products. Self-administered questionnaires were collected from 502 residents in the Daegu and Gyeongbuk area. According to the survey more females in their 20s responded than males (45.2 and 54.8%, respectively). In total, 82.6% of respondents had an income of under 4,000,000 won per month and most were living in the city. The results regarding knowledge about bokbunja products showed that the bokbunja wine score was highest (3.66), and intake frequency showed that over half of the respondents had never eaten bokbunja products. The preference for bokbunja wine by males was higher than that for females, whereas the others products showed higher scores for females than for males. When asked about how they knew about bokbunja products, 37.0% of males and 46.9% of females responded a family member or neighbor. When purchasing bokbunja products, males and females answered that they considered taste, country of origin, and manufacturer, and price. Approximately 48% of the respondents answered that they purchased bokbunja products in the grocery and department store. As a result, popularization of bokbunja products was based on product development and sales promotion, and the product development factor significantly influenced preference for bokbunja products.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.303-309
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• 2008

The physico-chemical properties of the rainfall interception culture (85 sites) and the open field culture soils (85 sites) in the area of Gochang-gun, Jeollabuk-do were surveyed. Soil textural distribution of the rainfall interception culture and the open field culture soils was 74% and 64% for silt loam, 16% and 35% for loam, and 10% and 1% for clay, respectively. The percentage of aggregate rates was higher in the open field culture soils (60.06%) than rainfall interception culture soils (55.84%). Electrical conductivity, exchangeable cations, and anions in the rainfall interception culture soils were higher than those in open field soils. Specially, accumulated amount of anion in rainfall interception culture soils was remarkably higher 2~3 times than open field culture soils. The results from the analyses of rainfall interception culture soils suggested that the most critical problem is the salts accumulation caused by over-fertilization of chemical fertilizer and compost. Therefore, application rates of chemical fertilizer and compost should be controlled in order to conservation of soil and water for sustainable agriculture.

• The Korean Journal of Ecology
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• v.23 no.5
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• pp.397-406
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• 2000

In order to clarify the ecophysiological characteristics of Chenopodiaceae which widely distribute on saline and arid habitats, we collected 10 chenopodiaceous plant species, examined their inorganic and organic solute patterns, and confirmed several common physiological characteristics. In spite of high soil Ca/sup 2＋/ contents, chenopodiaceous plants had a little water-soluble Ca within cells, but contained high contents of acid-soluble Ca particularly as a result of Ca-oxalate formation. These plant species also showed accumulation of inorganic ions such as K/sup ＋/, NO₃/sup －/ and Cl/sup －/, and Na/sup ＋/especially in saline habitats instead of K/sup ＋/ Meanwhile, with respect to nitrogen metabolism they retained high N contents in leaves, but showed very low amino acid contents. Additionally, they contained very little proline known to act as a cytoplasmic osmolyte. To ascertain whether this physiological characteristics in the field also can be found under controlled conditions, 7 chenopodiaceous plants (Atriplex gmelini, Corispermum stauntonii, Salicornia herbacea, Suaeda aspayagoides, Suaeda japonica, Chenopodium album var. centrorubrum, C. serotinum) were selected and cultivated under salt treatments. As well as field-grown plants, selected plant species showed similar solute pattern in growth experiment. In summary, the family of Chenopodiaceae represents the following physiological properties; high storage capacity for inorganic ions (especially alkali cations, nitrate and chloride), oxalate synthesis to maintain lower soluble Ca contents within cytoplasm, and low contents of amino acids. In addition to some characteristics mentioned above, the physiological plasticities of Chenopodiaceae which can properly regulate their ion and solute pattern according to soil conditions may enable its representative to grow in dry sand dune and salt marsh habitats.

• Journal of Aquaculture
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• v.9 no.1
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• pp.43-55
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• 1996

The experiment was performed to evaluate the possibility of utilizing underground sea water for the seed production of tiger puffer, Takifugu rubripes. For this purpose, the effects of 6 different salinities (3.5, 7.0, 14.0, 20.0, 27.0, $33.0\%_{\circ}$) were determined based on the hatching rate of fertilized eggs, survival rate and the amount of food consumed by hatched larvae, where as the effects of 3 different salinities (20.0, 27.0, $33.0\%_{\circ}$) were also examined with rearing tiger puffer juvenile ($4.29{\pm}0.50$ cm in total length) for 50 days in the closed recirculating water system. As a results, either the hatching or the survival rate of more than $70.0\%$ were obtained from the fertilized eggs reared at the salinity of 27.0 to $33.0\%_{\circ}$, the early hatched larvae at 27.0 to $33.0\%_{\circ}$, and the 10-day-old larvae at 20 to $33.0\%_{\circ}$. At three different salinities, the survival rate of 20-day- and 30-day-old larvae turned out to be $89.0\%$ and $92.5\%$, respectively. The salinity for maximum food intake thus appeared to be from 27.0 to $33.0\%_{\circ}$. In this condition, 20-day-old hatched larvae consumed $323\~342$ Artemia nauplii and 30-day-old hatched larvae ate $1,559\~1,5791$ A. nauplii. The highest growth rate of fingerlings were observed at the salinity $27\%$ and followed by 33.0 and $20.0\%_{\circ}$, respectively. The relationship between the days of rearing (X) and the total length (Y) of the fingerlings were as follows : $33.0\%_{\circ}$ group : Y=0.107X-2.532 (r=0.982) $27.0\%_{\circ}$ group : Y=0.116X-3.195 (r=0.975) $20.0\%_{\circ}$ group : Y=0.116X-2.693 (r=0.987) The slopes of regression line estimated from $27.0\%_{\circ}$ and $33.0\%_{\circ}$ groups were significantly different from that of $20.0\%_{\circ}$ group.

• Atmosphere
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• v.23 no.3
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• pp.293-305
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• 2013

Nonhydrostatic effects on convectively forced mesoscale flows in two dimensions are numerically investigated using a nondimensional model. An elevated heating that represents convective heating due to deep cumulus convection is specified in a uniform basic flow with constant stability, and numerical experiments are performed with different values of the nonlinearity factor and nonhydrostaticity factor. The simulation result in a linear system is first compared to the analytic solution. The simulated vertical velocity field is very similar to the analytic one, confirming the high accuracy of nondimensional model's solutions. When the nonhydrostaticity factor is small, alternating regions of upward and downward motion above the heating top appear. On the other hand, when the nonhydrostaticity factor is relatively large, alternating updraft and downdraft cells appear downwind of the main updraft region. These features according to the nonhydrostaticity factor appear in both linear and nonlinear flow systems. The location of the maximum vertical velocity in the main updraft region differs depending on the degrees of nonlinearity and nonhydrostaticity. Using the Taylor-Goldstein equation in a linear, steady-state, invscid system, it is analyzed that evanescent waves exist for a given nonhydrostaticity factor. The critical wavelength of an evanescent wave is given by ${\lambda}_c=2{\pi}{\beta}$, where ${\beta}$ is the nonhydrostaticity factor. Waves whose wavelengths are smaller than the critical wavelength become evanescent. The alternating updraft and downdraft cells are formed by the superposition of evanescent waves and horizontally propagating parts of propagating waves. Simulation results show that the horizontal length of the updraft and downdraft cells is the half of the critical wavelength (${\pi}{\beta}$) in a linear flow system and larger than ${\pi}{\beta}$ in a weakly nonlinear flow system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.63-69
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• 1972

There was a concentrated heavy rain resulted in 450mm of precipitation from Aug. 18 and 19, 1972. Almost all the paddy grown in the main plain areas of KimPo, Bu Cheon and Pyong Taek(N. L. $37^{\circ}$00'98'$-37^{\circ}$30'56", Long. $126^{\circ}$45'99"$-127^{\circ}$55'92"E) have been damaged of submergency. The effects of the different degrees of submergency in different growth stages of paddy, on the yield of paddy, rates of fertilization, maturity and degree of heading have been observed, and may be summarized as follows. (1) When the paddy was damaged due to submergency at the heading stage, a) on the basis of normal paddy, the yield of paddy may be expected about 67,57,40,9 and 6% with the submerged periods of 0.5, 1. 0, 2.0, 3.0 and 4.0 days, respectively, and a significant-negative correlation was found between the periods of submergency and the yields. b) As in the yield of paddy, rapid decreases in the rates of fertilizations and maturities of paddy were found as the submerged periods are increased. When the submerged periods are 0.5, 1.0, 2.0, 3.0 and 4.0 days, the corresponding rates of fertilizations and maturities observed are 89 and 88,83 and 78,52 and 40,24 and 19, and 12 and 9%, respectively, showing significant negrative correlations. c) Considerable decreases of the degree of heading were found as the submerged periods are increased. resulted in a significant negative correlation at 1% level between the degree of heading and submerged periods. (2) When the paddy plants were under submergency just before heading, the damage was found to be less than that at heading stage. The yields were 86,82,60,36 and 10%, as compared with the normal yield, with 0.5, 1.0, 2.0, 3.0 and 4.0 days of the submerged periods. (3) When the paddy was under the submergency at the mid-stage of head sprouting, its damage was severer than that of just before heading stage. The yields of paddy under the different submerged periods, 0.5, 1.0, 2.0, 3.0 and 4.0 days, were 79, 64, 34 and 6%, respectively, of the normal yields. normal yields.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.85-94
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• 1997

The study is aimed to find out the causes of rapidly increasing chloride (Cl$^{－}$) concentration of the Samyang 3rd pumping station originated from coastal springs of Cheju since January 1996. The study results show that it was caused by following complicated natural and anthropogenic effects. Due to severe draught in 1996 with total rainfall of only 41.7% of annual mean of the last 36 years (1991 to 1995), it creates firstly), significant decrease of the spring discharges as well decline of the groundwater level at the site . Sea water level was in general 4.4 cm to 12.4 cm higher than the groundwater level of the site during 2 to 3.8 hours at each high tide. Those higher potential head of sea water motivates the sea water intrusion into the fresh water lens through the permeable clinkers and fracture zones situated beneath the existing grouted zone which was installed to a maximum 10 m below the ground water surface, The repeated expansion and contraction of the fresh water lens occurred by periodic changes of the sea water level at high and low tide accelerates secondly the enlargement of the transition zone between the fresh and sea water at the site. The decrease of recharge amount by rainfall shortage creates thirdly the reverse flow at the interface of sea water and groundwater. The repeated groundwater extraction of 2790${\pm}$450 $m^3$d$^{－1}$ at the time of low tide, when the fresh water lens of the sire is under the contraction stare, makes additional drawdown of the ground water level and induces the upconing of salt water into the fresh water lens. The duration of spring discharge whose Cl concentration is less than 150 mg/1 at the low tide measured at the nearby springs was about two hours with discharge rate of 532 $m^3$d$^{－1}$ and after that Cl$^{－}$ concentration is increased up to more than 1900 mg/ι.eased up to more than 1900 mg/L.