• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.103-109
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• 2009

Soils originated from limestone, located at the southern part of Kangwon province and Jecheon, Danyang of Chungbuk province are mainly composed of fine texture, and have different properties from soils originated from granite and granite gneiss, especially for water movement. This study was conducted for classification of hydrologic soil group (HSG) of soils originated from limestone by measuring the infiltration rate of surface soils and percolation rate of sub soils. Soils used for the experiment were 6 soils in total : Gwarim, Mosan, Jangseong, Maji, Anmi and Pyongan series. Infiltration and percolation rate were measured by a disc tension infiltrometer and a Guelph permeameter, respectively. Particle size distribution and organic matter content of the soils were analyzed. HSG, which was made by USDA NRCS(National Resources Conservation Service) for hydrology, of Gwarim series with O horizon of accumulated organic matter was classified as type A which show the properties of low runoff potential, rapid infiltration and percolation rate. HSG of Mosan series, which has high gravel content and very rapid permeability, was classified as type B/D because of the impermaeble base rock layer under 50cm from surface. HSG of Jangseong series with shallow soil depth was classified as type C/D owing to the impermaeble base rock layer under 50cm from surface. HSG of Maji series was type B, and HSG of Anmi series used as paddy land was type D because of slow infiltration and percolation rate caused by the disturbance of surface soil by puddling. HSG of Pyeongan series having a sudden change of layer in soil texture was type D because of the slow percolation rate caused a the layer.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.40-49
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• 1999

A laboratory flume experiment, using turbulence-generating acryl tank and natural sediments, was conducted to investigate the effects of salinity, concentration of suspended sediment, turbulence and clay minerals on the flocculation and settling of fine-grained suspended sediments. While experiments were run, a sequence of water samples were taken near the bottom of the tank to analyze the variations of size distribution and relative contents of clay minerals. The results of the salinity experiment indicate that median settling velocity ($W_{50}$) increases linearly with salinity. Different settling processes of suspended sediments under variable concentrations appear to be predictable, depending upon the range of the suspension concentration. At concentrations less than 200 mg/l, $W_{50}$ is rarely varied with concentration probably because of the individual--grain settling mode. In the range of 200 to 13,000 mg/l show $W_{50}$ and concentration a good relationship following an empirical formula: $W_{50}=0.45C^{0.44}$. This relationship, however, no longer holds in concentrations exceeding 13,000 mg/l; instead, a more or less reverse one is shown. This result suggests an effect of hindered settling. The turbulence effect is somewhat different from that of concentration. Turbulence accelerates the flocculation and settling susepended sediments at low concentration (200 mg/l), whereas at high concentration turbulence breaks floes down and impedes the settling. Size distribution of suspended sediments sampled near the bottom of the tank tend to be more negatively skewed and leptokurtic in turbulent conditions compared to those in static conditions. The clay mineral analysis from the sequential water samples shows that over time the content of smectite decreases most rapidly with illite remaining concentrated in suspension. This means that smectite, among other clay minerals, plays the most effective role in the flocculation of fine-grained sediment in saline water.

• Journal of Animal Science and Technology
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• v.51 no.4
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• pp.265-272
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• 2009

A total of 486 milk records were collected from 16 diary farms in Imsil-gun, Jeollabuk-do. Results obtained were as follows: The average 3MG (amount of milk within the first three minute) was 7.44 kg and 55% of total milk yield was produced within 3 min. The average of SPL (% of foam in milk) was 33.93% and the average of MNG (strip yield) was 0.14 kg, which was less than 1% of total milk yield. The averages of HMF (highest milk flow), HMG (maximum milk flow rate in one minute) and DMHG (average milk flow in the main milking phase) were 3.03 kg/min, 2.94 kg/min and 2.05 kg/min, respectively and the average milking speed in Imsil-gun was slower than other regions. The average of tS500(time to reach 0.5 kg/min at beginning) was 0.23min (about 14 seconds) and that of tMGG (duration of the total milking) was 7.75min. The average tMBG (duration of the dry milking phase) was 0.58 min (35 seconds) and that of tMNG (duration of the stripping phase) was 0.42min (14 seconds). The averages of ELHMF (electrical conductivity at highest milk flow) and ELAP (beginning peak level of the electrical conductivity) were 6.81 mS/cm and 7.58 mS/cm, respectively. The average of ELMAX (maximum electrical conductivity) was 7.48 mS/cm and that of ELAD (beginning peak difference of the electrical conductivity) was 0.61 mS/cm. While the total milk yields for DMHG, tMHG (duration of the main milking phase), tPL (duration of the plateau phase), tAB (duration of the descending phase) and tMGG were positively correlated (0.35~0.54), those for tMBG and SPL were negatively correlated (-0.11 and -0.27). As the DMHG increased, tMHG, tPL, tAB, tMGG and SPL decreased. While the cows with higher electrical conductivity at the beginning of milking had less somatic cell counts, cows with higher electrical conductivity after the peak of milk yield had more somatic cell counts. The results of this experiment indicated that through milking based on milking and lactating standards and the regular checking of milking status, the qualities of milk and milk yields could be improved.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.233-239
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• 2010

Four genes (yqfR, yfmL, ydbR, deaD) were identified as putative DEAD-box RNA helicase genes in the genomic sequence of Bacillus subtilis by homology search. To understand the function of these genes, each of the genes was deleted and the constructed strains were tested for their growth charateristics at different temperatures. The growth rate of ydbR deletion mutant ($T_d$=53 min) was a little bit reduced at $37^{\circ}C$ as compared to that of wild type strain (CU1065). But the growth rate of other three (yqfR, yfmL, deaD) deletion mutants ($T_d$=30-40 min) is nearly equal to the growth rate of wild type ($T_d$=32 min). On the other hands, the growth rate of deletion mutants were reduced at $22^{\circ}C$ in order of yqfR ($T_d$=151 min), yfmL ($T_d$=214 min), ydbR ($T_d$=343 min), which showed cold-sensitive phenotype. The deletion mutant of deaD ($T_d$=109 min) grew equally as compared to the growth rate ($T_d$=102 min) of the wild type at $22^{\circ}C$ and did not show cold-sensitive growth. Double, triple and quadruple deletion mutants of these genes were constructed, and growth rate of these mutants were measured at various temperature conditions ($22^{\circ}C$, $37^{\circ}C$, $42^{\circ}C$) using LB broth. Multiple deletion mutations showed more severe cold-sensitive growth than single deletion mutations, and double deletion of ydbR and yfmL ($T_d$=984 min) showed most cold-sensitive growth than any other double mutants. Such a cold-sensitive growth of these mutations is quite similar to the result of csdA or srmB deletion in E. coli and suggested that physiological role of ydbR and yfmL is related with ribosome assembly.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.495-503
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• 2012

The water quality of Gul-po Stream, the subject of this study, has been deteriorating because of the inflow of domestic sewage and the industrial wastewater due to industrialization and the problems relating to the structure of river including slow flow rate and the covering of river. In particular, the domestic sewage from small-medium sized factories by the river and large-scale industrial complex by the upper and middle streams of the river, and the domestic sewage from increasing population due to the regional development are the main pollution sources. Thus, this study aims to survey the water quality and the sediment affecting Gul-po Stream; monitor the state of pollution in water body; assess the yield of sediment and investigate the water quality of river and the problems arising from sediment; and then suggest reasonable ways to improve the situation. The findings from surveying pollution load shows the discharge increases up to average 72.8 times from the upper stream to the downstream of Gul-po Stream, and pollution load increases up to: SS 111 times, BOD 150 times, COD 145 times, the nutrient T-N 222 times and T-P 312 times on an average basis. As for the pollution concentration range, ignition loss is 1.29~12.43%; COD is 4,015~37,547 kg/day; T-N and T-P 94.8~352.5 kg/day and 81.8~372.3 kg/day, respectively. As for the releasing rate of sediment, T-N is -14.46~$156.61mg/m^2/day$; T-P is -11.53~$26.10mg/m^2/day$, indicating the likelihood of internal contamination due to the elution of sediment. This study is expected to be used as basic data to manage Gul-po Stream basin.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.421-429
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• 2016

Tenebrio molitor larvae contain large amounts of proteins, lipids and other functional materials, enabling this insect to be used as an edible food source in animal feeds and for industrialization. Although many efforts have been made to set up mass rearing systems, few studies have been conducted to establish optimal rearing conditions for the production of high quality T. molitor larvae. Herein we investigated 1) the effects of additional diets on the survival and fecundity of the insect, 2) the relationship between oviposition period and the uniformity of larval size, 3) the effects of rearing density and temperature on insect development, and 4) the storage stability of eggs and pupae at low temperatures given possible temporary production discontinuation. The addition of carrot and zucchini to the traditional wheat bran diet significantly increased the survival and fecundity rate of adult T. molitor. Of the three different oviposition sampling periods (3, 7, and 14 days) used to investigate the uniformity of the hatched larvae in each treatment, the period of 3 and 7 days provided higher uniformity than the 14 days oviposition period. Larval development was faster at $30^{\circ}C$ than at 20, 25, and $35^{\circ}C$. Interestingly, oviposition rates were highest at $20^{\circ}C$ but showed much slower larval development and lower uniformity at $30^{\circ}C$. Regarding the effect of larval rearing densities (1, 10, 20, 30, 40, and 50 larvae per 90 mm diam. dish), larval weight was significantly reduced at higher rearing densities, but larval longevity and length were not influenced by rearing density. The 30 larvae/dish is suggested to be a reasonable density to be applied to mass production systems. When kept at $4^{\circ}C$, T. molitor eggs showed a significant reduction in hatching rate; however, when stored under the same conditions, pupae emergence rates remained high until 10 weeks, suggesting that storage at low temperatures is more suitable for the pupal stage than the egg stage. Our findings suggest that an increase in T. molitor adult survival and fecundity rates and a uniformity of hatched larval development can be achieved with the following recommendations: a combination diet (including wheat bran), a 7-day oviposition period; a larvae-rearing temperature of $30^{\circ}C$, a rearing density of 30 larvae/dish, and the storage of pupal stages at low temperatures in the case of rearing discontinuation. This study serves as a strong foundation for the successful mass production of high quality T. molitor larvae.

• Journal of the Korean earth science society
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• v.38 no.1
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• pp.64-79
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• 2017

We have reported the petrographic properties on the soda straw primarily based on the field measurements and discussed the causes of their traits. 156 soda straws in district B of the Baeg-nyong Cave nominated with the natural monument No. 260 have been investigated to estimate physical, sedimentological and textural characteristics. The soda straws have an average length of 3.05 cm with a standard deviation of 1.7 cm and a mean diameter of 6.0 mm. This result shows that the average diameter of the soda straws measured in this study is thicker than previous reports by 20%. Although the drip rates of cave water from 85.3% of all the soda straws are exceedingly lower than 1 drop per 10 minutes, almost all soda straws have a dripping water. We firstly report growth lamina in the Korean soda straw from 85.3% of all samples, and this textural dominance indicates that the growth lamina are one of the common features of the soda straws at least in the study area. Secondary precipitations inside the soda straw were identified from 68.6%. Notably, the strong inverse correlation between growth lamina and secondary precipitates was represented from 70.5% of all samples. This finding might be explained by the seasonality of cave drip water supplied into the soda straws or the increased opacity caused by secondary precipitates. Based on petrograhic characteristics, the soda straws in the study area can be classified into normal and erratic types. Hopefully our results on the soda straws in Baeg-nyong Cave would provide a basis for the descriptions of soda straws from other caves and paleoclimatic applications.

• The Korean Journal of Malacology
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• v.20 no.2
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• pp.125-130
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• 2004

Arkshell, Scapharca broughtonii spats were placed in natural environmental condition for 30 days from July 28 to August 27, 2004, in order to estabilish intermediate culture technique. Growth and survival of the spats in different intermediate culture areas with various culture methods were measured. Water temperature of studied area ranged from 24.1 to 28.5$^{\circ}C$, salinity was 15.4 to 33.3 psu, dissolved oxygen was 3.92 to 12.6 mg/l. Scapharca broughtonii spats cultured in Yeosu developed the best, 10.15 ${\pm}$ 1.12 mm in average shell length, and the highest survival was recorded as 77% in Namhae. Shell lengths of the Scapharca broughtonii spats cultured in the water depths of 2, 5, and 10 m were 7.14 ${\pm}$ 1.14 mm, 6.98 ${\pm}$ 1.74 mm and 6.27 ${\pm}$ 1.33 mm, and the survivals showed 75.5%, 77.0% and 76.5%, respectively. When 1 mm, 2 mm, and 3 mm-sized spats were cultured for 30 days in water depth of 5 m, the shell length increased to 6.73 ${\pm}$ 1.46 mm, 6.98 ${\pm}$ 1.74 mm and 7.04 ${\pm}$ 1.19 mm, and survivals were 67.0%, 77.0% and 58.5%, respectively. The shell lengths of spat cultured for 30 days in mesh sizes of 1 ${\times}$ 1 mm, 2 ${\times}$ 2 mm and 3 ${\times}$ 3 mm, 5 m below the surface were 8.14 ${\pm}$1.23 mm, 8.26 ${\pm}$ 1.19 mm and 8.78 ${\pm}$ 1.16 mm, and survivals were 41.5%, 43.0% and 44.5%, respectively.

• Journal of Mushroom
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• v.7 no.3
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• pp.105-109
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• 2009

Ten to thirty percent of ginko leaf pomace(GLP) were added to pine sawdust to investigate mycelial growth. Mycelial growth on the medium with GLP was 86~101(mm/28 days) and was slower than that of the control without GLP as, 102(mm/28 days). Mycelial growth time on medium of sawdust with 10 to 20% GLP was similar to the control without GLP as 29 days but that on medium with 30% GLP was delayed for 2 days. The time of pinhead formations of sawdust with 10 to 20% GLP was 7 days, the growth time to harvest was 11 days. These results were similar to those of the control without GLP. The sizes of pileus of treatments with 10 to 30% GLP were tend to be smaller compared with the control. The length of stipe of 10% GLP treatment was 98mm which was longer than that of the control with 91mm. The thickness of stipes of 10 to 30% GLP treatments were 45 to 48mm which were tend to be thicker than that of the control with 45mm. The hardness of stipe were 35,062($g/cm^2$) to 4,1065($g/cm^2$)) which were harder than that of the control with 32,156($g/cm^2$)). GLP treatments seem to be favorable to store or distribute. Yields per volume of GLP added treatments were 88.7g to 95.6g, which was increased 3 to 12% compare to 85.8g of the control without GLP.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.357-363
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• 2010

In this study, we investigated the geologic structure of the basement and overlying sediments of the construction site of the dinosaur egg fossil museum in Hwasung, Gyeonggi Province through refraction seismology, drilling, and downward seismic velocity measurements in the drill holes. The construction site ($350{\times}750\;m^2$) is located in the reclaimed area south of Sihwa Lake, Gojeong-ri. About 6,950 m of seismic refraction data consisting of 11 lines were acquired using a sledge hammer source. Drilling to the basement was performed at five sites. Sediment samples from drilling were analysed for grain-size distribution and age dating. At two drill holes, seismic velocity was measured with depth using a hammer as a seismic source. The geological structure of the study area consists of, from top to bottom, a tidal flat layer (5 ~ 12 m thick), a weathered soil layer (2 ~ 8 m thick), and the basement. The basement is interpreted as Cretaceous sedimentary rocks that tend to be shallow eastward. The volume of the tidal flat sediments and weathered soil in the study area is estimated as $1.4{\times}10^6\;m^3$, weighing $3.5{\times}10^6$ tons. The rate of sea level rise since 8,000 yrs BP is estimated to be 0.1 ~ 0.15 cm/yr.