• ALGAE
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• v.25 no.1
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• pp.37-44
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• 2010

A tide-simulating apparatus was developed for culturing marine macroalgae. The objective of this study was to introduce a novel tide-simulating apparatus that can simulate a diurnal or semi-diurnal tidal cycle in the laboratory. In this apparatus, the seaweeds are move up and down and the water level remains the same during the simulated tidal cycle. The apparatus consists of 18 cylindrical culture tanks (3 blocks $\times$ 6 culture tanks) with 12 cm diameter and 24.5 cm long containing up to 2.5 L of seawater. There is a horizontal plate which covered all 18 culture tanks, and it is raised and lowered by a programmable motor that can regulate exposure time. In one application, seaweeds are attached to braided twine hung on Plexiglas air-tubing. The air-tubing is attached to a lid that is set on a horizontal plate. This apparatus is made of colorless Plexiglas to maximize light transmittance. This apparatus is easily disassembled and transportable to any indoor laboratory, wet laboratory, greenhouse, etc. This apparatus also offers considerable flexibility in terms of design. The size of culture tank can be redesigned by either increasing the height of cylinder or/and using a different diameter of cylindrical Plexiglas, therefore, larger/taller thalli can be cultivated. Growth rates of three eulittoral Porphyra species from different tidal elevations have been compared using this device.

• Ocean and Polar Research
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• v.24 no.3
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• pp.237-247
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• 2002

We report all sky camera and Fabry-Perot interferometer (FPI) observations of mesospheric gravity waves and a 12-hour wave at Resolute $(75^{\circ}N)$ and a joint observation of 10-hour wave with Eureka $(80^{\circ}N)$. All sky camera observations showed a low occurrence of mesosphere gravity waves during equinoxes, which is similar to the mid-latitude region. A slightly higher occurrence near solstice appears to indicate that gravity waves are not filtered out by the neutral wind in the winter. The FPI observation of a 12-hour wave showed amplitude variations from day to day. The phase of the wave is mostly stable and consistent with the GSWM prediction in the winter. The phase shifts with season as predicted by the GSWM. Four events of the 12-hour wave were found in spring with amplitudes larger than the GSW predictions. The FPls at Resolute and Eureka also observed a wave with period close to 10 hours. The 10-hour wave maybe the result of the non-linear interaction between the semi-diurnal tide and the quasi-two day wave. Further studies are under way. Overall, the combined Resolute and Eureka observation have revealed some new fractures about the mesospheric gravity wave, tidal wave, and other oscillations.

• Journal of Environmental Science International
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• v.29 no.7
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• pp.749-760
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• 2020

This study investigates the characteristics of diurnal, seasonal, and weekly roadside and residential concentrations of PM₁₀ and PM_2.5 in Busan, as well as relationship with meteorological phenomenon. Annual mean PM₁₀ and PM_2.5 concentrations in Busan were 44.2 ㎍/㎥ and 25.3 ㎍/㎥, respectively. The PM_2.5/PM₁₀ concentration ratio was 0.58. Diurnal variations of PM₁₀ and PM_2.5 concentrations in Busan were categorized into three types, depending on the number of peaks and times at which the peaks occurred. Roadside PM₁₀ concentration was highest on Saturday and lowest on Friday. Residential PM₁₀ concentration was highest on Monday and lowest on Friday. Residential PM_2.5 concentration was highest on Monday and Tuesday and lowest on Friday. PM₁₀ and PM_2.5 concentrations were highest on Asian dust and haze, respectively. The results indicate that understanding the spaciotemporal variation of fine particles could provide insights into establishing a strategy to control urban air quality.

• Water Engineering Research
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• v.3 no.1
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• pp.31-44
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• 2002

The effect of diurnal cycle, intermittent visit of observation satellite, sensor installation, partial coverage of remote sensing, heterogeneity of soil properties and precipitation to the soil moisture estimation error were analyzed to present the global sampling strategy of soil moisture. Three models, the theoretical soil moisture model, WGR model proposed Waymire of at. (1984) to generate rainfall, and Turning Band Method to generate two dimensional soil porosity, active soil depth and loss coefficient field were used to construct sufficient two-dimensional soil moisture data based on different scenarios. The sampling error is dominated by sampling interval and design scheme. The effect of heterogeneity of soil properties and rainfall to sampling error is smaller than that of temporal gap and spatial gap. Selecting a small sampling interval can dramatically reduce the sampling error generated by other factors such as heterogeneity of rainfall, soil properties, topography, and climatic conditions. If the annual mean of coverage portion is about 90%, the effect of partial coverage to sampling error can be disregarded. The water retention capacity of fields is very important in the sampling error. The smaller the water retention capacity of the field (small soil porosity and thin active soil depth), the greater the sampling error. These results indicate that the sampling error is very sensitive to water retention capacity. Block random installation gets more accurate data than random installation of soil moisture gages. The Walnut Gulch soil moisture data show that the diurnal variation of soil moisture causes sampling error between 1 and 4 % in daily estimation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.152-158
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• 2006

The objective of this study is to investigate change in diurnal respiration and transpiration of the fruits of kiwifruit during fruit growth. Three-hourly fruit transpiration and respiration rate were measured by a chamber technique. Results showed a tendency of higher transpiration and respiration in at maturation to commercial harvest period in 1995 fruit than in 1996 fruit. Fruit respiration rates were very similar to the transpiration rates. The air temperature record for the fruit maturation period in 1996 showed a sudden drop on September $19{\sim}24$ and October 14 down to $7{\sim}13^{\circ}C$. These results suggest that abnormal fruit transpiration and respiration rate in the fruit maturation period might be influenced by the air temperature.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.2
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• pp.115-122
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• 1997

Diurnal variation of $PM_{10}$ concentration was investigated for 24 sites in library including reading room, bookstock room, lobby, office and so on, and 9 sites in student building at Kangwon National University using scattering light integrated type digital dust indicator. The dimensional conversion factors for mass concentrations (K) were determined by comparing between the $PM_{10}$ concentrations collected by $PM_{10}$ hig volume air sampler and the digital dust indicator. The dimensional conversion factor (K) was 3.33 for indoor air in this experiment. The highest concentrations were 649 $\mug/m^3$/day for smoking room in the library and 242 $\mug/m^3$/day for circle room in the student building. Most of spaces in the library except a office and bookstock rooms were over 150 $\mug/m^3$/day of $PM_{10}$ concentrations and 6 indoor spaces were over the guideline for indoor air quality in student building except a health center and two restaurants. Therefore, it should be required to make an improvement on the indoor air quaility for public facilities in the university buildings.

• The Korean Journal of Ecology
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• v.21 no.1
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• pp.89-96
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• 1998

The diurnal changes of the stomatal conductance, transpiration and leaf water potential were measured in order to assess the water relations characteristics of Pueraria thunbergiana in August of 1995 and 1996. The results showed two different responses depending on the duration of rainless days. The microclimatic conditions were highly stressful on 2 August. Daily maximum temperature reached to $39.0{\circ}C$ and vapor pressure deficit was 3.55 KPa. During this time the leaf water potential decreased to -1.02 MPa and a marked reduction of stomatal conductance was shown. However, on 15 August the stomatal conductance increased with increment of photon flux density, and transpiration was highly maintained during the day time. Minimum leaf water potential was only -0.47 MPa in spite of high transpiration rate. Furthermore, on 15 August reduced leaf water potential during the day time was recovered rapidly with decrease of photon flux density, whereas recovery of leaf water potential on 2 August was delayed. However, reduced leaf water potential on 2 August was recovered untile the next dawn. Osmotic potential at turgor loss point of Pueraria thunbergiana on 2, 3 and 15 August was -1.79, -1.70 and -1.60 MPa, respectively. The vapor pressure deficit is more contributive to the regulation of stomatal conductance than leaf water potential.

• Korean Journal of Occupational Health Nursing
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• v.18 no.1
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• pp.14-21
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• 2009

Purpose: This study was performed to investigate the effect of shift work on diurnal blood pressure (BP) pattern in nurses. Method: We studied 20 healthy nurses engaged in 3 shift work. 24-hour ambulatory BP monitoring was performed to each nurse two times during the day and night shift. Five nurses were excluded because of inadequate BP measurement. Results: All subjects were female. The mean age was 27.4 years (range: 23-33 years) and mean body mass index was 19.7 Kg/$m^2$ (range: 18.0-21.2 Kg/$m^2$). The changes of systolic BP ($17.8{\pm}9.1$ vs. $13.2{\pm}4.7%$, p=0.031), diastolic BP ($22.3{\pm}8.7$ vs. $17.3{\pm}9.0%$, p=0.061), and heart rate ($25.2{\pm}5.2$ vs. $12.5{\pm}8.7%$, p=0.001) during the sleeping period were decreased after a night shift compared with day shift. The non-dipper group significantly increased from 20% to 40% after a night shift (p=0.018). Conclusion: Working night shift is significantly associated with non-dipper status in nurses.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.7-14
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• 1996

Two experiments were conducted to evaluate breathing zone air quality in Taegu, using automatic analyzers for four air quality standards($SO_2$, $NO_2$, CO, and $O_3$). First, air target compounds were measured for 8 to 12 hours in each of two commercial areas and five residential areas. Second, air target compounds were hourly measured for 24 hours in each of two commercial areas, two residential areas, and an industrial complex area. Based on the first experiment the breathing zone air was more polluted in the commercial area as compared to the residential area, while the second experiment showed that the breathing zone air was polluted rather in the residential are3 as compared to the commercial area. The second experiment also indicated that there was some variation of breathing zone air concentration with time and measuring sites. Diurnal variation of breathing zone air concentrations was consistent with previous studies which measured at building height. The highest breathing zone air concentration was shown in Seongseo industrial complex area. An unusual finding of this study was that $SO_2$ concentration in the breathing zone air of Bisandong, a typical residential area of Taegu, was higher than that of other residential areas, even higher than that of Seongseo industrial complex area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.45-50
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• 1981

Diurnal changes in leaf stomatal resistances were measured on leaf positions and both surfaces to investigate the stomatal response to irradiance in wheat, var. Chokwang and barley, var. Dongbori 1. Stomatal frequency and size were also determined to explain the control mechanism of gas exchanges in two species. The leaf diffusive resistances of two species decreased, as the sun rose, to minimum at 10 to 11 o'clock a.m. and increased gradually in the afternoon, even faster at sunset. As the adaxial irradiance increased, stomatal resistances decreased sensitively in the range of 30uEm$^{-2}$ㆍsec$^{-1}$ to 150uEm$^{-2}$ㆍsec$^{-1}$ quantum flux density. The stomatal opening of the abaxial surface began at lower irradiance and was completed earlier than the adaxial surface. The adaxial irradiances decreased in order of leaf position, flag, the 2nd, the 3rd leaf, and the stomatal resistances increased in the same order. Even under the same irradiance, the stomatal resistance of lower leaves were higher than those of upper leaves. The stomatal frequencies of lower leaves were less, but the stomatal size was greater than those of upper leaves. Consequently, the relative leaf area occupied by stomatal pores were constant among leaf positions in two species.