• Journal of Wetlands Research
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• v.6 no.3
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• pp.55-70
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• 2004

The wetland ecosystem is a complex products of various erosion force, accumulation as water flows, hydrogeomorphic units, seasonal changes, the amount of rainfalls, and other essential element. There is no single, correct, ecologically sound definition for wetlands because of the diversity of wetlands and the demarcation between dry and wet environments occurs along a continuum, but wetland plays various ecosystem functions. Despite comprehensive integration through classification and impact factors there is still lacking in systematic management of wetlands. Classification system developed by the USFWS(1979) is hierarchical progresses from systems and subsystems at general levels to classes, subclasses, dominance types, and habitat modifiers. Systems and subsystems are delineated according to major physical attributes such as tidal flushing, ocean-derived salts, and the energy of flowing water or waves. Classes and subclasses describe the type of substrate and habitat or the physiognomy of the vegetation or faunal assemblage. Wetland classes are divided into physical types and biotic types. For the wise management of wetlands in Korea, this study was carried out to examine methodology of USFWS classification system and discuss its application for Korean wetland hydrogeomorphic units already known. Seven wetland types were chosen as study sites in Korea divided into some different types based on USFWS system. Three wetland types belonging to palustrine system showed no difference between Wangdungjae wetland and Mujechi wetland, but Youngnup of Mt. Daeam was different from the former two types at the level of dominant types. This fact means that setting of classification system for management of wetland is needed. Although we may never know much about the wetland resources that have been lost, there are opportunities to conserve the riches that remain. Extensive inventory of all wetland types and documentation of their ecosystem functions are vital. Unique and vulnerable examples in particular need to be identified and protected. Furthermore, a framework with which to demonstrate wetland characteristics and relationships is needed that is sufficiently detailed to achieve the identification of the integrity and salient features of an enormous range of wetland types.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.1-12
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• 2018

A gravity core (RS14-C2) was collected at site RS14-C2 in the continental slope to the east of Pennell-Isellin Bank of the Ross Sea (Antarctica) during PNRA XXIX (Rosslope II Project) Expedition. In order to trace the sediment source, magnetic susceptibility (MS), sand fraction, and clay mineral compositions were analyzed, and AMS $^{14}C$ ages were dated. Core sediments consist mostly of hemipelagic sandy clay or silty clay including ice-rafted debris (IRD). AMS $^{14}C$ age of core-top indicates the modern and Holocene sediments. Based on AMS $^{14}C$ dating, sediment color, MS and sand fraction, core sediments are divided into interglacial and glacial intervals. The interglacial brown sediments are characterized by low MS and sand fraction, whereas the glacial gray sediments are characterized by high MS and sand fraction. Among clay mineral compositions of core sediments, illite is highest (61.8~76.7%), and chlorite (15.7~21.3%), kaolinite (3.6~15.4%), and smectite (0.9~5.1%) are in decreasing order, and these compositions are also divided into the interglacial and glacial/deglacial intervals. During the glacial period, the high content of illite and chlorite indicate sediment supply from the bedrocks of Transantarctic Mountains under the Ross Ice Sheet. In contrast, because of decreasing supply of illite and chlorite by the glacial retreat, smectite and kaolinite contents increased relatively during the interglacial period. During the interglacial period, smectite may be transported additionally by the northeastward flowing surface current from the coast of Victoria Land in the western Ross Sea. Kaolinite may be also supplied to the continental slope by the Antarctic Slope Current from the kaolin-rich metasedimentary rock outcropped on the Edward VII Peninsula.

• Analytical Science and Technology
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• v.15 no.5
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• pp.417-426
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• 2002

Inductively Coupled Plasma Dynamic Reaction Cell Quadrupole Mass Spectrometry (ICP-DRC-QMS) was characterized for the detection of the six naturally occurring calcium isotopes. The effect of the operating conditions of the DRC system was studied to get the best signal-to-noise ratio. This experiment shows that the potentially interfering ions such as $Ar^+$, ${CO_2}^+$, ${NO_2}^+$, $CNO^+$ at the calcium masses m/z 40, 42, 43, 44 and 48 were removed by flowing $NH_3$ gas at the rate of 0.7 mL/min $NH_3$ as reactive cell gas in the DRC with a RPq value (rejection parameter) of 0.6. The limits of detection for $^{40}Ca$, $^{42}Ca$, $^{43}Ca$, $^{44}Ca$, and $^{48}Ca$ were 1, 29, 169, 34, and 15 pg/mL, respectively. This method was applied to the determination of calcium in synthetic food digest samples (CCQM-P13) provided by LGC for international comparison. The isotope dilution method was used for the determination of calcium in the samples. The uncertainty evaluation was performed according to the ISO/GUM and EURACHEM guidelines. The determined mean concentration and its expanded uncertainty of calcium was ($66.4{\pm}1.2$) mg/kg. In order to assess our method, two reference samples, Riverine Water reference sample (NRCC SLRS-3) and Trace Elements in Water reference sample (NIST SRM 1643d), were analyzed.

• Journal of radiological science and technology
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• v.34 no.4
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• pp.323-331
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• 2011

We evaluated clinical usefulness of Arterial spin labeling perfusion MR imaging on the acute ischemic cerebral infarction patients through this study. We compared 22 patients who were done with DSC imaging and ASL imaging in admitted emergency room with acute ischemic cerebral infarction, with 36 normal comparison persons (DSC image on 21persons, ASL images on 15persons). Siemens Magnetom Verio 3.0T with 12 channel head coil was used for this study. DSC image obtained 4 maps(rCBV, rCBF, rMTT, TTP) through post-processing. For qualitative analysis we compared the area of lesion macro-diagonal with the size of diffusion weighted MR image for rMTT, TTP, rCBF, rCBV, ASL maps. For Quantitative analysis we analyzed significant correlations between less than 3 cm infarction group and normal comparison group using mean relative value of flowing image with Mann-Whitney U test. TTP(95.5%) and rCBF(95.5%) maps showed high recognition rate in qualitative analysis for >3cm infarction group. The rCBF and rCBV map tests were highly related with final stage stroke areas. Mean relative value of infarction group showed a significant correlations in quantitative analysis(p<0.05). As a conclusion, arterial spin labeling image showed high lesion recognition rate in the >3cm infarction group. Mean relative values in quantitative evaluation were used for reference data. If we do more sustainable researches, ASL image will be useful for an early diagnosis of cerebral infarction, determination of the range of ischemic pneumbra and effective treatments.

• Korean Journal of Environmental Agriculture
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• v.10 no.1
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• pp.33-49
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• 1991

In order to disclose the contamination of the Mushim-Cheon by pollutants and to establish the countermeasures, the water samples collected in November of 1989(lst sample), February(2nd), May(3rd) and August of 1990(4th) were analyzed to obtain the following results : 1. The water temperatures of the seasonal samples ranged from 8.6 to 16.2, 8.3 to 25.2, 18 to 26, and 24 to 32$^{\circ}C$, in the 1st, 2nd , 3rd, and 4th samples, respectively. 2. The pHs of all the samples ranged from 6.5 to 8.5. 3. In the 3rd sample, especially, DO was observed to fall down to 0.8 ppm at the downstream of St 13, which is not allowed even for agricultural use. 4. The BOD and COD values in sewers were much higher than those in the main stream, and especially the values of St 14-A reached 107-608 and 176-635 ppm, respectively, which far exceeded the limit of 40 ppm, the allowed value for the discharges from the disposal facilities. The SS value of St 14A ranged from 142 to 1, 900 ppm, which far exceeded the limit of 70 ppm, the allowed value for the discharges from the disposal facilities. 5. It turned out that the water quality of the Mushim-Cheon flowing through Cheong Ju was more worsened at sewers than the main stream, and at the downstream than the upstream of the surveyed area. Accordingly, the sewage disposal plant and the expansion of the disposal facilities are urgently needed.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.726-734
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• 2019

To understand the relationship between water velocity in a fishway and fish morphology, the fineness ratio of fish, expressed as the standard length to the body depth, was measured. The fineness ratios of fish groups belonging to Cyprinidae, Acheilognathinae, Centropomidae, and Centrachidae were relatively low. The FRs of other groups, excluding eel-shaped types of fish, were over 4.5, indicating streamlined structures. The fineness ratios of Korean fish were classified into three different types: type I was Bitterling-Carp group that favored a slow-flowing pool habitat(FRs ranged from 2.1 to 3.3), type II was the Chub group representing streamlined types (FRs FRs ranged from 3.7 to 5.2), and type III was the Smelt-Barbel fish group that preferred riffle-run habitats with high velocity (FRs is over 5.2). Fish abundance analysis of fish using the fishway during the experimental periods showed a relatively high abundance of both type II and III compared to type I. The FRs of the fish passing through fishway(velocity 0.5-1.0 m s^-1) ranged from 4.5 to 5.0, indicating that the fish using the fishway were mainly the streamlined type. As one of the standard fishways in Korea, the flow rate of the ice harbor type ranged from 0.2 to 2.6 m s^-1. The FR values of the fish groups using the fishway ranged from 4.3 to 5.0. In contrast, the flow rate measured in an artificial channel type of fishway (same as a natural type of fishway) ranged from 0.1 to 1.9 m s^-1 and the FR values for the fish groups using a natural type of fishway ranged from 3.3 to 5.3. The low FR values in natural fish are considered to be due to differences in the flow rates between the two types of fishways.

• Korean Journal of Ecology and Environment
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• v.33 no.1 s.89
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• pp.51-60
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• 2000

In order to understand the trend and assessment of water pollution, seasonal water quality was determined in the main river and the tributaries from midstream to downstream of the Kum River from March 1998 to June 1999. Among environmental factors, the variation of nitrogen, phosphorus and chlorophyll-a was distinctive on an aspect of increase and decrease relatively to others, and particularly the impact of inorganic N ${\cdot}$ P inflowing into the main river was observed to be more significant at the Kapchon, Mihochon and Soksongchon among the tributaries. Water quality was highly related to hydrologic factor, and it was more deteriorated when water discharge maintains for a long time below normal flow or relatively at low condition of minimum and drought flow. These phenomena were remarkablee from December to March of the next year. $NH_4$ and SRP were decreased dramatically flowing toward the lower part of the river and chl-a was increased exponentially. While, the variations of $NO_3$ and $BOD_5$ were regular from midstream to downstream and there was no significant difference between the stations. Limiting nutrient for Phytoplankton growth seemed to be P than N because the ratio of TN/TP or DIN/SRP was relatively high as 42 or 544 in the main river, respectively. The main river and tributaries were ranked to be third grade, based on the assessment of BOD as an indirect indicator of organics, but particularly Kapchon was ranked to be over fifth grade. In addition, the inflow of high N ${\cdot}$ P nutrients from tributaries including Kapchon and Mihochon seemed to be major factor of the development of water pollution of the Kum River. On the other hand, persistent bloom of phytoplankton in lower part of the river was observed. As a conclusion, management of water quality for main source of pollution is urgent.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.1
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• pp.7-12
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• 2009

This experiment was conducted to compare the agronomic characteristics and productivity in introduced forage pea cultivars at the experimental field. The experiment was arranged in a randomized block design with three replications. The forage pea used in this study were two cultivars ('Livioletta', 'Austrian Pea') and one Chinese milk vetch cultivar (Chinese domestic cultivar). Flowing of 'Livioletta' cultivar was May 16th and 'Austrian Pea' cultivar was 18th May, 20 days later than the former. The 'Livioletta' cultlvar showed stronger than winter hardiness of 'Austrian Pea' cultivar. Dry matter (DM) content of 'Liviotetta' and 'Austrian Pea' cultivars were 22.5% and 20.9% chinese milk vetch showed the lowest content with 17.7%. 'Austrian pea' cultivar showed the highest DM yield with 5,617 kg/ha but the DM yield of 'Livioletta' cultivar was low with 3,652 kg/ha. The yield of CP (crude protein) and TDN (total digestible nutrient) set high at 'Austrian Pea' cultivar. And 'Livioletta' and 'Austrian Pea' cultivars showed CP content with 15.5% and 14.4% but Chinese milk vetch with 19.3%. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) content of 'Austrian Pea' cultivar were 23.2% and 40.3%. Therefore 'Austrian pea' cultivar seems to be suitable varieties in paddy field as winter forage crops.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.103-109
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• 1997

This experiment was conducted to investigate the effects of root zone warming on rhizosphere temperature of Oriental melon (Cucumis melo L. var. Makuwa) in winter season. Root zone was warmed by hot water flowing through pipe set at 35cm depth from the ridge. Treatments of minimum soil temperature at 20cm depth were 17, 21, $25^{\circ}C$, and non-warmed from Jan. 18 to Apr. 18. The results are summarized as follows. 1. The cumulative soil temperature for 1 month after planting oriental melon was 441, 558, 648, and 735$^{\circ}C$ at control, 17, 21, and $25^{\circ}C$ plot, respectively. 2. As soil temperature was higher, air temperature in tunnel was higher. The lowest temperature in control plot at night was 9.5$^{\circ}C$, 11.$0^{\circ}C$ in 17$^{\circ}C$ plot, 13.5$^{\circ}C$ in 21$^{\circ}C$ plot, and 16.5$^{\circ}C$ in $25^{\circ}C$ plot, respectively. 3. The xylem exudate amount of control plot for 24 hours just after basal stem abscission was 8.1$m\ell$. It was 1.2 times higher in 17$^{\circ}C$ plot, 1.3 times higher in 21 $^{\circ}C$ plot, and 4.8 times higher in $25^{\circ}C$ plot than in control plot at 30 days after planting. The xylem exudate amount at 67 days after planting of control plot was 10.4$m\ell$, those of 17, 21, $25^{\circ}C$ plots were 1.1, 3.2, and 3.3 times as compared to control plot. 4, Early growth in leaf length, stem diameter, leaf number and leaf area for 30 days after planting were better in higher temperature plots than in control plot. Particularly, the increase of leaf area was striking in higher temperature plots. Leaf area of control plot was 279.5$\textrm{cm}^2$ for 30 days after planting, 153.4% in 17$^{\circ}C$ plot, 745.6% in 21$^{\circ}C$ plot and 879.4% in $25^{\circ}C$ plot were increased as compared to in control plot.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.110-116
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• 1997

This experiment was conducted to investigate the effects of root zone warming on fruit yield of oriental melon (Cucumis melo L. var. Makuwa) in winter season. Root zone was warmed by hot water flowing through pipe set at 35cm depth from the ridge. Treatments of minimum soil temperature at 20cm depth were 17, 21, $25^{\circ}C$ and non-warming from Jan. 18 to Apr. 18. The results are summarized as follows. 1. The blooming of female flower was faster 1 days in 17$^{\circ}C$ plot, 6 days in 21$^{\circ}C$ plot, and 7 days in $25^{\circ}C$ plot than in control plot and the days from blooming to harvesting were shorter 5 days in 17$^{\circ}C$ plot, 11 days in 21$^{\circ}C$ plot, and 12 days in $25^{\circ}C$ plot than in control plot. 2. Mean fruit weight was the highest in 21$^{\circ}C$ plot, followed $25^{\circ}C$, 17$^{\circ}C$ and control plots, respectively, and flesh thickness was the highest in $25^{\circ}C$ plot, followed by 21, 17$^{\circ}C$ and control plots, respectively. 3. Early and middle-phase yield was the highest in $25^{\circ}C$ plot, followed by 21$^{\circ}C$, 17$^{\circ}C$ and control plots but late yield was the highest in 17$^{\circ}C$ plot, followed by control, 21, and $25^{\circ}C$ plots. Total yield per 10a was higher 33% in 17$^{\circ}C$ plot, 49% in 21$^{\circ}C$ plot, and 37a in $25^{\circ}C$ plots than in control plot, harvested 1, 490kg per 10a. 4. Total yield was highest in 21$^{\circ}C$ plot, followed by $25^{\circ}C$, 17$^{\circ}C$, and control plots. Malformed and fermented fruit rates were the highest in control, followed by 17, 25, and 21$^{\circ}C$ plots and marketable fruit rate was 21, 25, 17$^{\circ}C$, and control plot in order.