• Journal of Korean Society of Forest Science
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• 제100권2호
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• pp.202-211
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• 2011

The geometric characteristics of step-pool structures and how they are influenced by channel characteristics were investigated in a steep mountain stream in the Experimental Forests of Kangwon National University in Chuncheon, Gangwon-do. Average values of steps for the study reaches were as follows: step spacing, 4.69 m; step height, 0.47 m; step drop, 0.71 m; step-forming particle sizes, 0.68 m; number, 21steps/ 100 m; the ratio of step spacing to channel width, 0.5; and step steepness, 0.13. Relationships between spacing and height of steps and channel gradient showed a negative- and positive correlation, respectively, whereas all geometric variables of steps manifested poor correlation with channel width. Therefore, step steepness, expressed as the ratio of step height to step spacing, increased as channel gradient increased. The ratio of step steepness to channel gradient representing the criterion of maximum flow resistance was 1.2, indicating the channel bed's stable condition. In particular, the relationship between the ratio of step drop to step height and channel gradient showed a significant negative correlation, suggesting the influence of step-pool geometry in trapping sediment and providing an aquatic habitat. Positive correlations also exist between spacing and drop of steps and step particles. Our findings suggest that the dynamics of step-pool structures may strongly control physical and ecological environments in steep mountain streams, so understanding them is essential for stream management.

• Food Science and Preservation
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• 제22권2호
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• pp.167-173
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• 2015

This study was conducted to evaluate effect of adding cryoprotectant agents on the growth of lactic acid bacteria during storage of powdered Kimchi. Powdered Kimchi was prepared by adding 1.5% cryoprotectant (glucose, maltose, lactose, and sucrose) and freeze-dried. For the preparation of micro-sized particle of Kimchi powder, the freeze-dried Kimchi was powered at 14,000 rpm for 2 min. The survival ratio of lactic acid bacteria in the powdered Kimchi was monitored during storage period of 4 months at -20, 0, 4, and $25^{\circ}C$ after the capsulation of the powedered Kimchi. The number of lactic acid bacteria in the powdered Kimchi capsule was the greatest stored at $-20^{\circ}C$, and the addition of glucose in cryoprotectant showed higher survival rate of lactic acid bacteria than that of control. More than $10^7CFU/g$ of lactic acid bacteria were survived in the powdered Kimchi stored at 0 and $4^{\circ}C$. However, the lactic acid bacteria were not detected in the powdered Kimchi stored at $25^{\circ}C$. As a results, the addition of cryoprotectant agents in the manufacturing process improved the survival rate of lactic acid bacteria in powered Kimchi products with accompanying with a cold-chain system for the distributon of powdered Kimchi products.

• The Plant Pathology Journal
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• 제18권4호
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• pp.192-198
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• 2002

Mixed infections of two economically important viruses, Turnip mosaic virus(TuMV) in the family Potyviridae and Ribgrass mosaic virus(RMV) in the genus Tobamo-virus, were studied ultrastructurally on oriental cabbage. TuMV-ACl8 (alpine isolate in Korea) induced chlorotic spots on inoculated leaves of both ‘SSD63’ inbred line known as susceptible to TuMV, and ‘Tambok’ commercial cultivar, known as resistant to the virus, in the early stages of infection. TuMV-C5 (Taiwan isolate) caused severe mosaic and malformation on the upper leaves of ‘SSD63’, and necrotic spots in both inoculated and upper leaves of ‘Tambok’. RMV-CA1 (oriental cabbage isolate from alpine in Korea) induced vein chlorosis, leaf malformation, and midrib necrotic streak in the upper leaves of both ‘SSD63’ and ‘Tambok’. Both oriental cabbages infected with a combination of TuMV-ACl8 and RMV-CA1 showed synergistic symptoms of severe yellowing, severe mosaic, and necrotic spot or vein necrosis on their leaves. A combination of TuMV-C5 and RMV-CA1 produced synergistic symptoms only in ‘SSD63’. In ‘Tambok’ infected with the combination of TuMV-C5 and RMV-CA1, the number of necrotic spots on the inoculated leaves was one half lesser than that on singly infected with TuMV-C5. A few necrotic spots progressed systemically. In cells infected with a combination of TuMV-ACl8 and RMV-CA1 or TuMV-C5 and RMV-CA1, the particles of the two viruses made nonagon-like rings(NLR); one TuMV particle was surrounded loosely by nine RMV particles. Two unrelated viruses of TuMV and RMV were compacted in the central part of the spiral aggregates(SA) that was induced strikingly in cells by the mixed infections. The SA showed NLR in its center of the cross-sectioned side. Many particles of RMV of Tobamovirus were closely associated with Potyvirus-characteristic cylindrical inclusions. The SAs in the mixed infections were formed easily by the Potyvirus of TuMV-ACl8 or -C5 isolates.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제15권7호
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• pp.4665-4674
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• 2014

The aim of this study was to confirm the feasibility of the electro-coagulation process as a pre-treatment for the membrane separation of anaerobic digestion effluents to minimize membrane fouling. The reduction of membrane fouling was evaluated according to the number of electrodes (immersed surface area of electrodes), current density and contact time. In the case of the small surface area of electrodes, the increased electric field strength resulted in a soluble COD increase due to the destruction of the microbial flocs and/or cells, whereas large changes in the soluble COD were not observed in the case of the high surface area of electrodes. On the other hand, the T-P concentration decreased as a result of the precipitation of aluminum ions and phosphates. The membrane permeation flux increased and the fouling resistance (Rc+Rf) decreased with increasing electric current density. Although the particle size of the anaerobic digestion effluent increased slightly, it was not related directly to the reduced fouling phenomena. The main mechanism for the enhanced flux was attributed to the inorganic particulate produced during electrocoagulation, such as $AlPO_4$, which acted as a dynamic membrane deposited on the membrane surface.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제47권4호
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• pp.177-186
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• 2015

Until Mandelbrot introduced the concept of fractal geometry and fractal dimension in early 1970s, it has been generally considered that the geometry of nature should be too complex and irregular to describe analytically or mathematically. Here fractal dimension indicates a non-integer number such as 0.5, 1.5, or 2.5 instead of only integers used in the traditional Euclidean geometry, i.e., 0 for point, 1 for line, 2 for area, and 3 for volume. Since his pioneering work on fractal geometry, the geometry of nature has been found fractal. Mandelbrot introduced the concept of fractal geometry. For example, fractal geometry has been found in mountains, coastlines, clouds, lightning, earthquakes, turbulence, trees and plants. Even human organs are found to be fractal. This suggests that the fractal geometry should be the law for Nature rather than the exception. Fractal geometry has a hierarchical structure consisting of the elements having the same shape, but the different sizes from the largest to the smallest. Thus, fractal geometry can be characterized by the similarity and hierarchical structure. A process requires driving energy to proceed. Otherwise, the process would stop. A hierarchical structure is considered ideal to generate such driving force. This explains why natural process or phenomena such as lightning, thunderstorm, earth quakes, and turbulence has fractal geometry. It would not be surprising to find that even the human organs such as the brain, the lung, and the circulatory system have fractal geometry. Until now, a normal frequency distribution (or Gaussian frequency distribution) has been commonly used to describe frequencies of an object. However, a log-normal frequency distribution has been most frequently found in natural phenomena and chemical processes such as corrosion and coagulation. It can be mathematically shown that if an object has a log-normal frequency distribution, it has fractal geometry. In other words, these two go hand in hand. Lastly, applying fractal principles is discussed, focusing on pulp and paper industry. The principles should be applicable to characterizing surface roughness, particle size distributions, and formation. They should be also applicable to wet-end chemistry for ideal mixing, felt and fabric design for papermaking process, dewatering, drying, creping, and post-converting such as laminating, embossing, and printing.

• Journal of the Society of Cosmetic Scientists of Korea
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• 제37권4호
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• pp.289-295
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• 2011

Recently, the number of customers who want natural cosmetics without petroleum originated cosmetic ingredients is increasing over the world, however, there are few natural cosmetics that claim functionality in the products. Because there are few functional cosmetic ingredients from nature and though so, it is very difficult to stabilize the final products manufactured by using those functional cosmetic ingredients in the long period. This study is on stabilization of oleanolic acid, insoluble anti-wrinkle cosmetic ingredients from nature, with hydrogenated lecithin in the solubilization product, aiming for developing a formulation of solubilization products which can be certified as organic cosmetics. In case of other synthetic solubilizers, they showed unstability at $45^{\circ}C$ within 2 ~ 3 days, however, for natural origin hydrogenated lecithin a stable product was made without particle size change during 4 weeks. The stability of oleanolic acid in the solubilization product was measured for 24 weeks at $25^{\circ}C$ and $40^{\circ}C$, both samples showed over 90 wt% value of the initial one, which can prove that oleanolic acid was stabilized in the product without any degradation. Also through clinical tests, the effect of moisturizing, anti-wrinkle, safety were confirmed.

• Journal of the Korean Geosynthetics Society
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• 제18권4호
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• pp.1-13
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• 2019

The purpose of this study is to examine the effect of soft ground improvement by dynamic replacement with utilizing crushed rock. In order to understand the ground improvement effect when applying dynamic replacement method with crushed rock, the laboratory test and field test were performed. The internal friction angle and apparent cohesion were derived through direct shear test. The dynamic replacement characteristics were identified by analyzing the weight, drop, and number of blows needed for dynamic replacement. Through the field plate bearing test and density test, the bearing capacity and settlement of the improved ground were measured, and the numerical analysis were conducted to analyze the behavior of the improved ground. In this study, it proposes modified soil experimental coefficient(C_DR) to 0.3~0.5 in the dynamic replacement method with crushed rock. Also when applying the dynamic replacement method using crushed rock, the particle size range is less than 100 mm, D₉₀ is less than 80 mm and D₁₅ is more than 30 mm.

• Journal of Korea Water Resources Association
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• 제50권1호
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• pp.55-64
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• 2017

This study presents a numerical model for simulating turbidity currents using the ULTIMATE scheme. For this, the layer-averaged model is used. The model is applied to laboratory experiments, where the flume is composed of sloping and flat parts, and the characteristics of propagating turbidity currents are investigated. Due to the universal limiter of the ULTIMATE scheme, the frontal part of the turbidity currents at a sharp gradient without numerical oscillations is computed. Simulated turbidity currents propagate super-critically to the end of the flume, and internal hydraulic jumps occur at the break-in-slope after being affected by the downstream boundary. It is found that the hydraulic jumps are computed without numerical oscillations if Courant number is less than 1. In addition, factors that affect propagation velocity of turbidity currents is studied. The particle size less than $9{\mu}m$ does not affect propagation velocity but the buoyancy flux affects clearly. Finally, it is found that the numerical model computes the bed elevation change due to turbidity currents properly. Specifically, a discontinuity in the bed elevation, arisen from the hydraulic jumps and resulting difference in sediment entrainment, is observed.

• Applied Chemistry for Engineering
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• 제10권7호
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• pp.1052-1060
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• 1999

Tire and raw material of tire, i.e., SBR were degraded using pyrolysis process. The yield of pyrolytic oil was increased and that of gas was decreased with increase of operating temperature in pyrolysis. And the yield of pyrolytic oil was increased and that of gas and char was decreased with increase of heating rate. The maximum oil yields of SBR and tire were 86% and 55% each at $700^{\circ}C$ with a heating rate of $20^{\circ}C/min$. The number average molecular weight ranges of SBR and tire were 740~2486, 740~1719, and the calorific value of SBR and tire was 39~40 kJ/g. The oil components were consisted of mostly 50 aromatic compounds. The particle size was decreased and the surface area was increased with increase of operating temperature, and the BET surface area was $47{\sim}63m^2/g$. The optimum condition of pyrolysis was the temperature of $700^{\circ}C$ with heating rate of $20^{\circ}C$, and the reactor was continuously purged with inert gas to sweep the evolved gases from the reaction zone.

• Korean Journal of Clinical Pharmacy
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• 제21권3호
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• pp.256-269
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• 2011

Omega-3 fatty acids are a specific type of unsaturated fat that the body cannot manufacture on its own, so they must be obtained from food which is essential fatty acids (EFAs). Omega-3 fatty acids consist of three types which are a-Linolenic Acid (ALA), Eicosapentaenoic (ELA), and Docosahexaenoic Acid (DHA). Especially, EFAs help to prevent skin and hair drying, acne, eczema, prevention from allergies, brittle nails, rashes, and tiny lumps. The aim of this study is to investigate improvement and protection for hair damaged by chemical treatment with omega-3 formulated shampoo. We selected virgin hair sample and divided into two groups for bleaching once and three times and then damaged hair by changing the number of hair bleaching (twice with interval of 15 minutes). Each bleached hair was treated by five different kinds of shampoo (Control, Horse shampoo, DHA shampoo, EPA shampoo, Omega-3 shampoo mixture). Apart from this, EPA/DHA 2, 5, 8, 10 and 12% shampoo were prepared and treated to hair for comparing rate of progress in damaged hair. To quantify improved condition of damaged hair, we performed Scanning Electron Microscope (SEM) for ultrastructure of damaged hair fraction, measurement of thickness change and BCA Protein Assay for recovery rate of damaged hair. The moisture in hair was measured by Thermal analysis machine. In results, we observed the particle of hair surface damaged by bleaching treatment were well improved with treatment with EPA and DHA shampoo. Also, quantity of protein was lowered with higher concentration of EPA & DHA i.e., 8 and 12 % then compared with horse oil shampoo in three times treatment group. It shows that bleached hair have been recovered by treating rapidly and get protective coat. In conclusion, EPA and DHA shampoo improved damaged hair, especially with EPA / DHA 12% shampoo. Also, EPA shampoo could protect the damaged hair depending on increasing concentration of EPA. Therefore, we conclude omega-3 shampoo could make damaged hair protect and get healthy hair environment.