• Journal of Ecology and Environment
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• v.29 no.4
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• pp.353-360
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• 2006

Ecological correlates of flowering times often are examined to infer evolutionary mechanisms for flowering time diversities. We examined ecological characteristic associations such as growth habits and pollination modes with flowering times among 3,037 Korean angiosperms experiencing strong climatic seasonalities. We first examined taxonomic membership effects on flowering times across diverse taxonomic levels. Phylogeny constrained flowering times at all levels down to the genus level. We then analyzed the effects of ecological characteristics using subset data consisting of species randomly selected from each genus to control phylogenetic effects. The commonly observed patterns of early flowering of woody species in temperate regions existed. Spring flowering shrubs and trees, however, both being woody, were involved with biotic and abiotic vectors, respectively. In two herbaceous groups of annuals and perennials, annuals flowered later in the growing season than perennials although both herbs tended to be associated with abiotic vectors when flowering in autumn. These results support our hypothesis that species able to decouple vegetative and reproductive growth flower in spring's dry season, but species with different habits, even when they flower within the same season, are subjected to different selective pressures for efficient pollination.

• Journal of the Korean earth science society
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• v.44 no.4
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• pp.291-306
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• 2023

Shallow groundwater in rural areas is primarily polluted by agricultural activities. Nitrate-nitrogen is an indicator of artificial pollution. In this study, the hydrochemical characteristics and nitrate-nitrogen pollution of shallow groundwater were examined in two agricultural villages (Hyogyo-ri and Sinan-ri) in Chungcheongnam-do Province, Korea. Physicochemical quality analysis of shallow groundwater and stream water in the field, and chemical analysis in the laboratory were conducted from July 2020 to October 2021. In Hygyo-ri and Sinan-ri villages, shallow groundwater mainly belonged to the Ca-Cl, Ca-H CO₃, Na-HCO₃, and Na-Cl types, whereas stream water predominantly belonged to the Ca-HCO₃ type. The nitrate-nitrogen concentration in shallow groundwater varied depending on the season, displaying an increased concentration of nitrate-nitrogen in the dry season compared to the rainy season. Stream water may be influenced by runoff into villages from the surrounding area, although both shallow groundwater and stream water are affected by artificial pollution. In addition, the nitrate-nitrogen concentration in stream water was lower than that in shallow groundwater.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.170-174
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• 1994

Atmospheric lead concentrations in Seoul were monitored for ten years from January 1984 to June 1993 using X-ray fluorescence Spectrometer. 342 aerosol samples were collected using high volume samplers at two sites : one at Chungang University campus from 1984 to 1988 and the other at Yonsei University campus from 1989 to 1993. Lead concentration increased steadily from about 300ng/㎥ to the maximum of about 600ng/㎥ in 1988 and then decreased, and this is similar to the pattern of Korean leaded gasoline sales implying that Korean automobile emission is the main source. However, the emission from nation's coal combustion appeared to be substantial as welt, and this emmision is the major cause for the secondary feature strong seasonal variability. Lead concentration varied systematically from season to season, low in summer and high in winter. The region's characteristic climate, frequent and heavy precipitations in summer and dry in winter is considered to be another cause for the seasonal variability.

• The Korean Journal of Ecology
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• v.6 no.2
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• pp.90-97
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• 1983

Seasonal changes of the soil nutrient contents and aboveground biomass, relationship between the soil nutrients and the productivity, and the net efficiencies of solar energy conversion were studied in two reeed communities (Phragmites communis Trin.) at the salt marsh in the estuary of the Sumjin-River from April 30 to October 9, 1981. The inorganic nutrients such as exchangeable sodium and potassium of soil were decreased during growing season. The amounts of organic matter, exchangeable sodium and potassium, total nitrogen, and available phosphorus in stand $\prod$ were much more than those of stand $\coprod$ . Productivity of Phragmites communis was positively correlated with the soil nutrients such as available phosphorus, exchangeable potassium and total nitrogen. The maximum dry matter productions of the aboveground parts in stand $\prod$ stand $\coprod$ were $ 1, 120g/m^2; and; 843g/m^2$ in August, and the net coversion efficiencies of PhAR based on growing season (April to September) were 1.77% and 1.33%, respectively.

• 한국해양학회지
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• v.16 no.1
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• pp.24-30
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• 1981

In order to investigate water pollution of heavy metals in the Nagdong Estuary, samples were collected five times from August 1978 to April 1979 every other month, and analyzed for Cd, Cu, Pb and Zn by atomic absorption spectrophotometry. The results showed no significant heavy metal pollution in most parts of the studied areas, except near the outfalls of the Sasang Industrial Complex. In general, the heavy metal contents were higher in the dry season than in the rainy season due to the dilution effect of river water flow. Distribution of heavy metals in the dissolved and the particulate fractions were also investigated.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.311-319
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• 1999

In Korea accelerated industry development and urbanization during the last three decades have led serious water pollution problems in many parts of the nation. Especially in the regions of west and south coast have low fresh water in the dry season of spring and summer. In the place isolated from land it is important to secure the fresh water for drinking and general service. This study is concerned on the thermal system design to develop low-pressure evaporation type fresh water gen-erator of capacity 1 ton/day using the heat source of non-operating boiler in the season of spring and summer. The results obtained from this study are as follows. the water quantitieds generated from experi-mental evaporator showed good coincidence with the calculated values. The maximum production quantity was 1.38ton/day at pressure 40mmHg abs. and temperature $80^{\circ}C$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.13 no.1
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• pp.17-25
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• 1977

For four calender years (1971-1974), daily observations of weather conditions (air temperature, humidity, wind speed, wind direction, cloud amount, fog, precipitation etc.) at six stations in the north western Pacific Ocean are used to calculate mean monthly values and to check extra-conditions. At Petropavlosk and Miko'skoe, where indicate the characteristics of modified continental climate, the temperature and humidity are high in summer, and Iow in winter. At A Dak and She Mya, where indicate the characteristics of warm current type maritime climate, humidity is high in all season and annual range of air temperature is nearly negligible. At Simusir and Vasi!' eva, where indicate the characteristics of cold current type maritime climate, humidity is high in all season and annual range of air temperature is $15^{\circ}C.$ As dry cooling power is relatively high in winter, working condition on deck is bad. Most of fogs are advection fog in the area of cold current type climate in summer.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.4
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• pp.278-287
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• 1993

In order to calssify smog type durnig the summer season in Seoul, air Quality and meterorological data were analyzed by multivariate analysis. Among 15 variables relating to visibility, 10 variables were selected by multiple regression analysis for clustering of smog types; total suspended particle, sulfur dioxide, ozone, ntrogen dioxide, total hydrocarbon, south-north wind component, ralative humidity, precipitable water, mixing height and air temperature. Somg types were grouped into three clusters using cubic clustering criterion and the mumbers of days in each cluster were contained 74, 28 and 16 days. Each cluster was seperated clearly by sulfur dioxide, precipitable water and air teperature. The first cluster was representative of high ozone concentration and prevailing meterological conditions for ozone formation. Therefore, visibility in the first cluster was considered to be affected by photochemical smog. The third cluster showed characteristics of sulphurous smog type due to the higher concentration of primary pollutant, based on the dry condition than that in another cluster. On the other hand, the characteristic of the second cluster was not relatively clear, but considered to be in an intermediate characteristic between photochemical smog and sulphurous smog type.

• Journal of the Korean Society of Floral Art and Design
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• no.42
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• pp.145-156
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• 2020

The purpose of this study was to investigate status survey on flower products with high sales by item and peak season. The survey was implemented for 103 people who are running flower shop and are members of association for Engineer Floral Design who are acquired Craftsman Floral Design and Engineer Floral Design. The result of this study, the peak season for the sale of flower product is showed May (52.0%) and February (24.3%). The reason for the selection was in May, month of family, teacher's day, etc. in February, personnel transfer and graduation ceremony. As a result of researching flower products with high sales volume by category, Cut flowers were ranked the first place of bouquet (51.5%%, 40.3%) and the second place of basket (28.8%, 37.5%) on annual and peak season. And also, Corsage, which was 6^th (1.8%) in the annual sales volume survey, increased to 3^rd (8.0%) during peak season. Pot plants were ranked 1st of foliage plant (50.6%, 51.3%) and 2nd tropical orchid·oriental orchids (27.4%, 28.3%) on annual and peak season. And also, Charcoal and bonsai, which were unresponsive in the annual sales survey, increased sales volume to 0.7% and 2.6%, respectively, during peak season. Processed flowers were highest ranked dry flower (45.3%, 39.5%), preserved flower (27.7%, 37.2%) on both non peak season and peak season. And then followed by artificial flower, pressed flower and collage.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.1
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• pp.16-25
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• 2012

To calculate the total mass flux that change in dry and flood season in the Yeomha Channel of Gyeonggi Bay, the 13 hour bottom tracking observation was performed from the southern extremity. The value of the total mass flux(Lagrange flux) was calculated as the sum of the Eulerian flux value and stroke drift value and the tidal residual flow was harmonically analyzed through the least-squares method. Moreover, the average during the tidal cycle is essential to calculate the mass flux and the tidal residual flow and there is the need to equate the grid of repeatedly observed data. Nevertheless, due to the great differences in the studied region, the number of vertical grid tends to change according to time and since the horizontal grid differs according to the transport speed of the ship as a characteristic of the bottom tracking observation, differences occur in the horizontal and vertical grid for each hour. Hence, the present study has vertically and horizontally normalized(sigma coordinate) to equate the grid per each hour. When compared to the z-level coordinate system, the Sigma coordinate system was evaluated to have no irrationalities in data analysis with 5% of error. As a result of the analysis, the tidal residual flow displayed the flow pattern of sagging in the both ends in the main waterway direction of dry season. During flood season, it was confirmed that the tidal residual flow was vertical 2-layer flow. As a result of the total mass flux, the ebb properties of 359 cm/s and 261 cm/s were observed during dry and flood season, respectively. The total mass flux was moving the intertidal region between Youngjong-do and Ganghwa-do.