• Journal of The Geomorphological Association of Korea
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• v.23 no.3
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• pp.105-122
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• 2016

To evaluate the changes in the physical characteristics of open rainfall related to canopy effects and rainfall intensity in Korea, the terminal velocity of raindrops and drop size distributions(DSD) were continuously measured by an optical-laser disdrometer in an open site(Op) and in two forest stands(Th1: Larix leptolepis, Th2: Pinus koraiensis) during five rainfall events in 2008. The terminal velocity, DSD and two forms of kinetic energy(KE, $Jm^{-2}$ $mm^{-1}$; KER, $Jm^{-2}$ $h^{-1}$) of open rainfall drops were determined and were compared with those of throughfall drops under two different canopy heights. The effects of the canopy and rainfall intensity, together with wind speed, on the changes in drop size and kinetic energy of throughfall were evaluated. Throughfall drops were larger than open rainfall drops. The distribution of terminal velocities for the drop sizes measured at Th2 was lower than that at Op; however, at Th1 the distribution was similar to that at Op. The total kinetic energy of throughfall at Th1 and Th2 was higher than the total kinetic energy of open rainfall, and the kinetic energy distribution for the drop sizes wassimilar to the drop size distribution. The observed throughfall-KER at Th1 was lower than an estimate previously produced using a model. The overestimation from the modeled value at Th1 was likely to be due to overestimated values of a square root transformation of fall height and its coefficient in the model because the distributions of terminal velocity for the drop size measured at Th1 were similar to those of open rainfall.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.182-188
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• 1982

A fluorometric method is described which permits the assay of trypsin inhibitor contained in a sample in an extremely small amount, utilizing a novel reagent generally called fluorescamine. The fluorometric assay with an enzyme kinetic approach has been found to be at least 100 times more sensitive than the well-known Kunitz's spectrophotometric method, considerably taster and less complicated, when it was demonstrated with the anti tryptic activities of very dilute extracts from soybean, red-bean and mung bean. Details of experimental procedure as well as theoretical considerations will be discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.371-378
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• 2020

Rainfall is one of the most active forces that cause soil erosion. The action of rain on the soil exerts an erosive power caused by the impact of the drops, which fall with variable speed and kinetic energy, depending directly on the diameter of the drop. The objective of this study is to determine algorithms capable of estimating rainfall erosivity for the region of Maceió-AL. For this purpose, erosion rains were collected between 2003 and 2006 using a RD-69 disdrometer, which continuously and automatically measures rainfall distribution in a range of 1 min. The determination of algorithms in the form of power equation to estimate was adjusted with one and two independent variables (amount of rainfall, duration and maximum intensity).

• Journal of the Korean Geographical Society
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• v.41 no.6 s.117
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• pp.657-669
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• 2006

Rates and processes of bare patch denudation were observed at Janggumokoreum(1,710m) and Minoruem(1,600m) in order to clarify some characteristics of turf exfoliation in the subalpine grassland of Mt. Halla. The bare patches have marginal terrace fronts with a maximum height of 85 cm. The terrace risers usually develop an overhanging edge 2 to 38 cm long that eventually hangs down and protects the riser beneath. The patches are largely covered with angular pebbles and cobbles. The mean rate of riser retreat for the period 2002-2004 is 39.2 mm, equivalent to 19.6 mm/yr. However, there is a disparity of the rate of riser retreat at individual sites. The maximum rate is 131 mm measured at Janggumokoreum patch while the minimum rate is 0 mm at Minoreum patch. The rate of riser retreat also varies with seasons. The thawing season of April exhibits a maximum rate of retreat. The freezing season of October and November and the rainy season of June and July show relatively high rates of retreat. Several Processes such as frost action, aeolian deflation, rainwash, rainsplash and fauna activity cause the denudation of bare patches. In particular, the needle ire action which is combined with rainwash or deflation plays a primary role in turf exfoliation due to the diurnal freeze-thaw cycles occurred over 100 days, melted snow and strong wind in the subalpine zone of Mt. Halla. Rainwash is also an important contributing process in the rainy season because Mt. Halla has the highest precipitation in Korea. By contrast, rainsplash erosion has a minor effect on the bare patch denudation due to the overhanging edge of terrace risers. Recent increase in roe deer appears to be responsible for turf destruction.

• Journal of the Korean Geographical Society
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• v.43 no.3
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• pp.296-311
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• 2008

In order to examine the rates and factors of path widening in Mount Halla, the retreat of path sidewalls was monitored at 32 sites of Seongpanak Hiking Trail located between 875 m and 1,400 m in elevation. The mean rate of sidewall retreat for the period 2002-2008 is 50.6 mm, equivalent to 10.0 mm/yr. The retreat rate of frozen period is 19.3 mm/yr, while the rate of unfrozen period is 4.3 mm/yr. The latter is divided into the rainy and dry periods that exhibit the retreat rates of 5.9 mm/yr and 2.9 mm/yr, respectively. The retreat rate of sidewalls is also varied with seasons; winter shows the maximum rate of 42.2 mm/yr, while summer exhibits the minimum rate of 1.3 mm/yr. Spring and fall show the intermediate rates of 13.9 mm/yr and 6.4 mm/yr, respectively. Soil hardness and elevation are not closely related to the retreat rate of sidewalls, even though the retreat rate is larger at the north-faced sidewalls than the south-faced sidewalls during the frozen period. Pipkrake is likely to be the most important factor contributing to the path widening in that the retreat of winter months accounts for 76.7% of the total retreat. The hiking trail is placed under the climatic conditions which develop pipkrake in 85 days annually. In addition, it is usual to observe the path sidewall covered with pipkrake in the freezing month of December and the thawing months of March and April. On the other hand, deflation and rainsplash erosion are not important due to the weak wind speed and the forested trail. Rainwash is also insignificant in that the path has been almost paved to mitigate trampling effects. Although biological activity is not dominant, hikers cause a large retreat of sidewalls in the thawing months since they would walk on the sidewalls to avoid snow-melting pools on the path.