• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.707-718
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• 2019

Ecklonia cava Kjellman, which has recently gained popularity due to the spread of farming techniques, is expected to be developed in various varieties in the future. There exist increased needs for research on the basis of natural populations and inter-regional morphological variations. We compared the morphology of the aquaculture and natural populations from 16 coastal areas in Korea. The 18 traits found suitable for distinguishing varieties were selected from 14 measurement traits and 4 ratios related to the main morphology and characteristics of primary blade, secondary blade, and stipe. In the cluster analysis, Janggil (E4) and Sorok (S7) showed significant differences from those of the same coastal region. Two groups, including Suyou (Q6, Q8, and Q10) which was the second year of farming, of the rest of the populations from East sea and southern coast were distinguished. Three populations of Jeju were divided into a regional group. In the principal component analysis (PCA), a large number of populations from East sea and Southern coast appeared in the center with aquaculture populations. PC1 and PC2 associated with traits of secondary blade index, stipe length and diameter, stipe length/primary blade length, primary blade length and width, secondary blade number, secondary blade length and width, divided E4, S7 and populations of Jeju region. As a result, the 18 characters of this study were found to be useful as criteria for discrimination of populations with significant differences in each coastal region, and these populations were expected to be candidates for new varieties.

• Economic and Environmental Geology
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• v.36 no.4
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• pp.285-293
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• 2003

Tailings of Dukum mine in the vadose and saturated zone were investigated to reveal the mobility of metal elements and the condition of mineralogical solubility according to redox environments throughout the geochemical analysis, thermodynamic modelling, and mineralogical study for solid-samples and water samples(vadose zone; distilled water: tailings=5 : 1 reacted, saturated zone; pore-water extracted). In the vadose zone, sulfide oxidation has generated low-pH(2.72∼6.91) condition and high concentration levels of S $O_4$$^{2-}$(561∼1430mg/L) and other metals(Zn : 0.12∼l57 mg/L, Pb : 0.06∼0.83 mg/L, Cd : 0.06∼l.35 mg/L). Jarosite$(KFe_3(SO_4)_2(OH)_6)$ and gypsum$(CaSO_4{\cdot}2H_2O$) were identified on XRD patterns and thermodynamics modelling. In the saturated zone, concentration of metal ions decreased because pH values were neutral(7.25∼8.10). But Fe and Mn susceptible to redox potential increased by low-pe values(7.40∼3.40) as the depth increased. Rhodochrosite$(MnCO_3)$ identified by XRD and thermodynamics modelling suggested that $Mn^{4+}$ or $Mn^{3+}$ was reduced to $Mn^{2+}$. Along pH conditions, concentrations of dissolved metal ions has been most abundant in vadose zone throughout borehole samples. It was observed that pH had more effect on metal solubilities than redox potential. How-ever, the release of co-precipitated heavy metals following the dissolution of Fe-Mn oxyhydroxides could be the mechanism by which reduced condition affected heavy metal solubility considering the decrease of pe as depth increased in tile saturated zone.

• Korean Journal of Environmental Agriculture
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• v.28 no.2
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• pp.125-130
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• 2009

The aim of this study was to investigate whether differences in the distribution of soil invertebrates among different vegetation types (forest, reservoir, and crop land types) in rural area. A total of 18 orders and 137 species were collected by pitfall traps. Species numbers were the lowest (33 species) at the Chamaecyparis obtusa plantation (St. 6). On the forest sites, the individual number of Hymenoptera was the most abundant, and Acari and Coleoptera was the relatively more abundant than the other sites. On the reservoir sites (Salix chaenomeloides community), the individual number of Collembola was the most abundant, and Diptera was the relatively more abundant than the other sites. On the crop land sites, the individual numbers of Collembola, Hymenoptera, and Araneae were the relatively more abundant than the other orders. The density of Araneae was higher in the reservoir and crop land sites than in the forest sites. From a point of view of biodiversity, although the diversity index(H') was the highest in the mixed broad-leaved forest type (St. 2) with Quercus serrata and Q. acutissima, and the lowest in the upland levee of crop land(St. 11), there was no significant difference among the habitat or vegetation types. According to the community analysis, the soil invertebrates could be divided into 4 groups, the mixed broad-leaved forest type (A group), the plantation or pure forest type (B group), the reservoir type (C group), and the crop land type (D group).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.139-151
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• 2007

To protect the surface of ground-cutting slopes and ground-raised slopes and to recover environment-friendly slopes at the national road expansion construction between Gamchon and Yaechon, test-construction work was done using several modes of hydro-seeding measures to select a suitable construction method through the field survey; the results were as follows : As a result of survey on physio-chemical characteristics of soil, the average soil inclination on ground-raised slopes was from 4.73 mm to 5.37 mm; the average soil acidity was from pH 6.47 to 6.73; the average soil humidity was within the scope of 0.57~1.70 %,; the average soil inclination on ground-cutting slopes was 9.17~10.43mm; the average soil acidity was pH 6.67~6.77 and the average soil humidity was within the scope of 0.53~1.27 %; considered overall, they showed generally satisfactory base materials for plant breeding. As a result of the number of sprouting individuals, the average sprouting number of individuals on test spots executed by Coir net with Seed spray construction methods and the average number of sprouting individuals on other test spots executed by furrow-digging with Seed spray and Straw mat-mulching measures were 1,172 number of per square meter and 970 number of per square meter respectively; thus they showed higher numerical value comparing with other test spots. Likewise, the average number of sprouting individuals on test spots of the ground-cutting slopes executed by Coir net with Seed spray method and the average number of sprouting individuals on other test spot executed by furrow-digger with Seed spray and Straw mat-mulching measures were found to be 1,107 number of per square meter and 1,105 number of per square meter respectively, whose numerical value showed rather higher other test spots. As a result of a survey on living plants' breeding index [dried weight], the weight in dried state on test spots executed by Coir net with Seed spray method and other test spots executed by furrow-digger with Seed spray and Straw mat-mulching measures on both ground-raised and ground-cutting slopes was found to be higher and showed similar characteristics statistically. As a result of survey on the surface-covering degree of ground-raised slopes, nine weeks after test construction, test spots executed by Coir net with Seed spray method and other test spots executed by furrow-digger with Seed spray and Straw mat-mulching measures showed commonly more than 70% of surface-covering degree, but other test spots showed only below 35% of surface covering degree; especially in case of test spots by Verdvol seed spray measures, they showed 10% of the lowest surface-covering. Surface-covering degree on the test spot of ground-cutting slopes nine weeks after test construction showed more than 75% both executed by Coir net with Seed spray construction method and executed by furrow-digger with Seed spray and Straw mat-mulching measures. As a result of survey on appearing plants on the test spots, there dominates Eragrostis curvula both on ground-raised slopes and on ground-cutting slopes with other seeding plant life's lower breeding and there appear intruders, such as Setaria viridis Beauv, Digitaria sanguinalis Scop, and Chenopodium album var.centrorubrum Makino. As for water-borne excavation and soil's washing-away on the slopes, there happened less washing-away and water-borne excavation with good breeding of plant life on test spots executed both by Coir net with Seed spray construction method and by furrow-digger with Seed spray and Straw mat-mulching measures, but there happened much more soil's washing-away along with water-home excavation at the test spot executed by Seed spray with measures. After the research results of test construction sites are examined overall, it's presumed that furrow-digger with Seed spray and Straw mat-mulching measures [interval between lines is 40cm, 5cm in depth] will be preferred to prevent erosion and water-home excavation of slopes located within the construction sites.

• Tuberculosis and Respiratory Diseases
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• v.55 no.6
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• pp.570-578
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• 2003

Background : Ambient particles during Asian dust events are usually sized less than $10{\mu}m$, known to be associated with the adverse effects on the general populations. But, there has been no considerable evidence linking these particles to the adverse effects on airways. The objectives of this study was to investigate the possible adverse effects of Asian dust events on respiratory function and symptoms in subjects with bronchial asthma. Patients and Methods : From march to June 2002, Asthmatic patients who were diagnosed with bronchial challenge test or bronchodilator response were enrolled. We divided them into three groups; mild, moderate, and severe, according to the severity. Subjects with other organ insufficiency such as heart, kidney, liver, and malignancy were excluded. All patients completed twice daily diaries and recorded peak flow rate, respiratory symptom, and daily activity. Daily and hourly mean pollutant levels of particulate matter < $10{\mu}m$ in diameter($PM_{10}$), nitrogen dioxide($NO_2$), sulphur dioxide($SO_2$), ozone($O_3$) and carbon monoxide(CO) were measured at the 10 different monitoring sites. Results : Dust events occured 14 times during the study period. Daily averages of 4 air pollutant were measured with an increased level of $PM_{10}$, decreased level of $NO_2$ and $SO_2$, and no change in CO during dust days compared to those during control days. An increase in $PM_{10}$ concentration was associated with an increase of subjects with PEF variability of >20% (p<0.05), night time symptom(p<0.05), and a decrease in mean PEF (p<0.05), which were calculated by the longitudinal data analysis. Otherwise, there was no association between $PM_{10}$ level and bronchodialtor inhaler, and daytime respiratory symptoms. Conclusion : This study shows evidence that ambient air pollution, especially $PM_{10}$, during Asian dust events, could be one of the many aggravating factors at least in patients with airway diseases. This data can be used as a primary source to set up a new policy on air environmental control and to evaluate the safety of air pollution index. We also expect that this research will help identify precise components of dust, which are more linked to the adverse effects.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.135-143
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• 2008

An emergy concept was used to evaluate the environment and economy of the estuarine areas of Yeongsan River, Seomjin River, and Han River in Korea. The emergy evaluations clearly showed ecological and socioeconomic characteristics of the estuarine areas that act as ecological and economic centers of surrounding areas. River, tide, and rain provided most of the renewable emergy inputs to the estuarine areas with their contribution to the total emergy input less than 8%. The estuarine areas mostly relied for their operation on the purchased emergy which accounted for $92{\sim}98%$ of the total emergy input to the systems. Emergy indices such as emergy use per unit area, population carrying capacity, environmental loading ratio, and emergy sustainability index revealed that the estuarine areas of Yeongsan River, Seomjin River, and Han River are not sustainable at the current level of economic activities in the areas. The ecological economic values of the environment of the areas were in the range of $7.29{\sim}22.06$ million Em\/ha/yr. They are more than twice that for the whole country, indicating the ecological and economic importance of the eatuarine areas. It is, therefore, urgent to establish and implement estuarine management policies to protect and restore the ecological and economic potentials of the estuarine areas of Yeongsan River, Seomjin River, and Han River. Management plans for the estuarine areas should include both demand-side measures such as reduction of population and economic concentration and consideration of ecological carrying capacity in planning stages for utilization and development of the areas, and supply-side ones such as restoration of degraded ecosystems and construction of new productive ecosystems.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.487-494
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• 2017

There is little evidence on the effects of environmental tobacco smoke (ETS) on prevalence of periodontal disease. The aims of this study were to explore the trends of prevalence of periodontal disease and types of exposure to smoke, including ETS according to the survey year, identify factors affecting periodontal disease, and compare the effect size of periodontal disease between active smokers and secondhand smokers. Data on 11,643 individuals were obtained from the fourth and fifth Korean National Health and Nutritional Examination Surveys. Information on exposure to ETS at home and work was self-reported. Severity of periodontal disease was evaluated using the community periodontal index. A multivariate logistic regression analysis was performed to model periodontal disease using types of smoking and the survey year. Overall, the prevalence of periodontal disease was 26.0% (n=3,029) and about 9% of the study population were secondhand smokers. The prevalence of periodontal disease among smokers was significantly increased according to smoking types by year. Active smokers showed a statistically significant adjusted odds ratio (aOR) for having periodontal disease except in the year 2007, whereas secondhand smokers had significant associations only in 2010 (aOR, 1.68; 95% confidence interval, 1.05 to 2.70) compared to non-smokers. For secondhand smokers, the statistical relationship of predicting periodontal disease was weaker than that of active smokers. However, ETS should separately be considered as an important risk factor for periodontal disease. This study suggested the need for further investigation of the impact of ETS on prevalence of periodontal disease using in-depth research designs and objective measurements for assessing periodontal disease and ETS.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.147-156
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• 2010

This study was conducted from April, 2002 to March 2006, using three urban streams(Gap Stream, Yudeung Stream and Daejeon Stream) in Daejeon Metropolitan City. 12,027 individual birds summed by the peak count in 126 species, 34 families, and 13 orders were observed from three stream sites. Dominant species were of Anas poecilorhyncha, Anas crecca, Columba livia, Passer montanus, and Egretta garzetta(in that order). The groups of birds were classified into six types. The most frequent group were the arbor birds(54 species), while the smallest group was the diving ducks(7 species). As for the number of individuals, the shrub bird group had 721 individuals while the dabbling ducks observed had 4,974 individuals. Regarding the distribution of birds appeareing in each stream, 14,885 individual numbers in 114 species were observed at Gap Stream, 6,642 individuals in 90 species at Yudeung Stream and 4,202 individuals in 69 species at Daejeon Stream. Various indices of the birds were analyzed with respects to the similarities between streams. Gap Stream had similar characteristics to Yudeung Stream, and the latter was similar to Daejeon Stream. However, Gap Stream and Daejeon Stream showed different characteristics. The dominance index of each section was calculated using ten dominant bird species top-down. Subsequently, the birds and their preferred environment were analyzed. The results showed that shrub birds and arbor birds preferred the upper stream of every stream, while herons and dabbling ducks inhabited the midstream. Dabbling ducks and some diving ducks appeared downstream.

• Korean Journal of Environment and Ecology
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• v.21 no.1
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• pp.55-66
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• 2007

This study was conducted to analyze the distribution patterns of wintering waterbird communities in relation to local environmental factors in the urban streams of Seoul, Korea. A field survey was conducted at 66 sites of 5 tributaries and the main channel of the Hangang River in Seoul in January 2006. The total of 65 species and 39,560 individuals were recorded in the field survey. There were 48 species and 28,989 individuals in the Hangang River, 14 species and 1,395 individuals in the Tancheon stream, 15 species and 2,306 individuals in the Jungrangcheon stream, 22 species and 5,990 individuals in the Anyangcheon, 18 species and 283 individuals in the Changrungcheon stream, and 24 species and 597 individuals in Gokrungcheon stream. The dominant species were Anas platyrhynchos (22.65%), A. poecilorhyncha (14.01%), Aythya ferina (13.26%), Aythya fuligula (8.04%), and Mergus merganser (7.03%). Among the 16 species (with 30,650 individuals) of ducks, the dabbling and diving ducks were 8 species with 18,286 individuals and 8 species with 12,364 individuals, respectively. Through the principal component analysis, the study sites were classified into four main groups according to the similarity of their waterbirds' species compositions: 3 tributaries in the urban area (Group 1), 2 tributaries in the rural area (Group 2), one in the rural area, one in the urban area, the urban area in Hangang River (Group 3) and the main channel of the Hangang River in the urban area (Group 4). Species diversity index and species evenness were the highest in Group 1, while the lowest Group 2. Analysis on their environmental factors showed that the waterbirds wintering in urban streams of Seoul prefer broad water width, low water depth and broad resting sites.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.844-861
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• 2008

The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.