• Journal of Ginseng Research
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• v.6 no.1
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• pp.84-99
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• 1982

Water content and its seasonal change in reprodltctive organs were reviewed in relation to cultivation practice s. Precipitati on and humidity under shade roof were reviewed in relation to shading ,jystem and environmental factors. High water content of reproductive organs suggests vulnerability to water stress during reproductive growth stage. Watering during dehisconce treat menu seems to keep optimum temperature but cnoventional practice seems to be too often In watering. Information effe on water physiology of seeds is too rare to develop seed storing method and ctive seed use. Dehiscent mechanism was considered in terms of water absorption of embryo. Precipitation rate of conventional shade roof reaclled to 38% and at line level 50% and varied with shade patterns. Precipitation rate under shade has been investigated for itself but should be investigated in relation to light intensity and soil moisture content Relative humidity under shade depends mainly on air humidity and soil moisture, considerably on shade materials and lithe on pole height, bed width or plant density. Since relative humidity was lower in afternoon it was often less than 50% even in summer with high temperature suggesting possible disorder of phi biological function especially in photosynthesis. More information was needed on optimum humidity for productive physiological function of leaf.

• Journal of Biosystems Engineering
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• v.19 no.2
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• pp.112-123
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• 1994

At present, no appropriate drying conditions can be found for the heated-air drying of mushroom in Korea. Usually, mushroom is being dried at the temperature range of 40 to $50^{\circ}C$ until the moisture content reaches 10~13% (wb). However, drying characteristics of the mushroom should be investigated for quality improvement and efficient drying operation of the mushroom. The results of this study may be summarized as follows ; 1. The effect of air temperature on the rate of drying was greater than that of relative humidity for drying of mushroom, and the rate of drying was increased with increase in the air temperature. 2. Drying rate for Shiitake mushroom showed falling-rate period of drying without constant-rate period of drying. Drying rate for Oyster mushroom showed a short constant-rate period at the initial stage of drying process, and followed by falling-rate period of drying. 3. Exponential and App.-Diffusion models were found to describe well the drying process of Shiitake mushroom. Exponential and Thompson models for Oyster mushroom in which Thompson model was the most suitable for Oyster mushroom. 4. The equilibrium moisture content of the mushroom decreased with decrease in the air temperature and increase in the relative humidity. In room condition($20^{\circ}C$, 54% RH), the calculated values of the equilibrium moisture content showed 11.17% for Shiitake mushroom and 13.19% for Oyster mushroom, respectively.

• Journal of Powder Materials
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• v.9 no.4
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• pp.227-234
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• 2002

For the austenitic stainless steel (304L) manufactured by metal injection molding(MIM), the effects of copper content and sintering temperature on the mechanical properties, antibacterial activities, corrosion resistance, and electric resistances were investigated. The specimens were prepared by injection molding of the premixed powders of water-atomized 304 L and Cu with poly-acetyl binders. The green compacts were prepared with various copper contents from 0 to 10 wt.% Cu, which were debound thermally at 873 K for 7.2 ks in $N_2$gas atmosphere and subsequently sintered at various temperatures from 1323 K to 1623 K for 7.2 ks in Ar gas atmosphere. The relative density and tensile strength of the sintered compacts showed the minimum values at 5 and 8 wt.% Cu, respectively. Both the relative density and the tensile strength of the specimen with 10 wt.% Cu sintered at 1373 K showed the highest values, higher than those of copper-free specimen. Antibacterial activities investigated by the plastic film contact printing method for bacilli and the quantitative analysis of copper ion dissolved in water increased as the increase of the copper content to stainless steels. It was also verified by the measurement of pitting potential that the copper addition in 304 L could improve the corrosion resistance. Furthermore the electric conductivity increased with the increase of copper content.

• YAKHAK HOEJI
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• v.32 no.5
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• pp.313-318
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• 1988

Radioprotective ginseng protein fraction was isolated from Korean white ginseng and its cytotoxic effect on CHO-K1 cells was studied by the method of measuring the relative cell survival and total cellular protein content (FRAME method). When ginseng protein at the dose of 300, 600, 900, $1200{\mu}g/ml$ was treated to cells for 24 hrs, the relative survival was significantly decreased at the concentration of above $600{\mu}g/ml$, indicating the presence of cytotoxic effect of the protein at certain concentration. When cellular protein content was measured after ginseng protein at the dose of 300, 600, 900, $1200\;{\mu}g/ml$ was treated, the amount of cellular protein was significantly reduced at the concentration above $600{\mu}g/ml$ in the case of 24 hr treatment and at all concentrations including $300{\mu}g/ml$ in the case of 72 hr treatment. The data suggest that the protein may inhibit cell growth, resulting in the reduction of live cells in culture. $ID_{50}$ value which is the concentration of ginseng protein that reduces the total cellular protein content to 50% of the control was calculated as 2276.86 and $1323.32\;{\mu}g/ml$ in groups treated for 24 and 72 hr, respectively. Since $ID_{50}$ value of above $1000{\mu}g/ml$ indicates very weak cytotoxicity, the ginseng protein seems to exert very weak cytotoxic effect on CHO-K1 cells.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.320-325
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• 1985

Relation between amylose and physical properties of milled rice was investigated. Amylose content was negatively and positively correlated with chalkiness and alkali solubility, respectively. No correlation was observed between amylose content and water uptake rate, cooked rice hardness or relative crystallinity. Relative crystallinity of the starch was negatively correlated with alkali solubility and water uptake rate.

• Food Science of Animal Resources
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• v.18 no.2
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• pp.176-184
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• 1998

The objective of this study was to investigate the effects of freezing rate on aroma retention and to examine the mechanism of aroma retention during freeze drying process. Our experiments were carried out with self-manufactured freeze-dryer. Gelatin gels (2% w / w, 80${\times}$20mm) containing diacetyl(2mg/ml) were frozen unidirectionally (Neumann's model) from the bottom at -45, -30, -20, and -15$^{\circ}C$ and followed with freeze-drying. Under the upper conditions we measured freezing rate and the change of temperature and pressure during freeze drying. Freeze-dried gelatins were cut horizontally into 5 mm thickness from the bottom measured and diacetly contents. Besides, we observed the effect of the relative humidity of the diacetyl contents freeze-dried gelatin during storage. The retained diacetyl content was increased at high freezing temperature and in order of 0∼5, 5∼10, 10∼15, 15∼20 mm section from the bottom of the sample. It was observed that the retained diacetyl content was high in 15∼20 mm section. The retained diacetyl content and freeze-dried gelatin stored in the condition of high relative humidity was decreased significantly but in the low relative humidity case, was it decreased in small amount. The results of our experiment resents that the low temperature freezing and low humidity storing condition is effective for preserving aroma compound in food.

• Journal of Biosystems Engineering
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• v.16 no.1
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• pp.60-82
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• 1991

Drying process of red pepper is very important in terms of drying cost and quality of the end product. Recently, many studies on red pepper drying have been performed. Nevertheless, an optimum drying condition is not established yet. Drying characteristics of red pepper is much affected by drying factors such as variety and initial state of red pepper as well as by environmental drying factors such as temperature and relative humidity of drying air. Various varieties of red pepper are being cultivated and the initial state of red pepper at harvest is very ambiguous. For this reason, it is very costly and time-consuming to establish an optimum drying condition of red pepper by experiment. A general drying model to descirbe a drying process has not been developed due to diversity of drying characteristics of red pepper. This study was, therefore, performed to develop a general drying model describing a drying process of red pepper. The results from this study are summarized as follows. 1. A basic model was established to develop an appropriate mositure content model and temperature model describing a drying process of red pepper, and the basic model was validated with experimental data. 2. The bone dry weight of fruit and mositure content were accepted satisfactorily as parameter to define the arbitrary red pepper. 3. The equilibrium moisture content of red pepper was found out to be different according to the variety of red pepper, air temperature and relative humidity. Also, the EMC model was developed using the parameters of air temperature, relative humidity and bone dry weight of fruit. 4. A general drying model for red pepper was developed, parameters of which were expressed as the function of drying factors related with drying phenomena. The developed drying model was found out to describe well the drying process of red pepper.

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.237-243
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• 2001

The prediction model is proposed to estimate the variation of compressive strength of fly ash concrete with aging. After analyzing the experimental result with the model, the regression results are presented according to fly ash replacement content and water-cement ratio. Based on the regression results, the influence of fly ash replacement content and water-cement ratio on apparent activation energy was investigated. According to the analysis, the model provides a good estimate of compressive strength development of fly ash concrete with aging. As the fly ash replacement content increases, the limiting relative compressive strength and initial apparent activation energy become greater. The concrete with water-cement ratio smaller than 0.40 shows that the limiting relative compressive strength and apparent activation energy are nearly constant according to water-cement ratio. But, the concrete with water-cement ratio greater than 0.40 has the increasing limiting relative compressive strength and apparent activation energy with increasing water-cement ratio.

• Journal of the Korean GEO-environmental Society
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• v.12 no.2
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• pp.23-33
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• 2011

In this paper, we got soil-water characteristic curve(SWCC) of Nak-Dong River's sand respectively as relative density 40%, 60%, 80% and content of silt 0%, 10%, 20%, 30%. As a result, the more the sand densify in the same silt content and the more the sand has silt in the same relative density, the change of volume water content was decreased. we have known effect of silt contents for SWCC and verified existing empirical formula of SWCC. As experiment results of soil-water characteristic curves compared to the empirical solutions, the results of van Genuchten(1980) and Fredlund & Xing(1994) were well-matched showing S type curves with experiment results. Especially the empirical solution of Fredlund & Xing showed almost same results of the coefficient of correlation($R^2$) equal to 0.99.

• The Journal of Engineering Geology
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• v.27 no.3
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• pp.217-231
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• 2017

The subsidence of ground in urban area can be caused by the occurrence of the cavity and the change in ground volumetric water content. The objective of this study is the detection of abnormal area of ground in urban area where the cavity or the change in ground volumetric water content is occurred by the ground penetrating radar signal. GPR survey is carried out on the test bed with a circular buried object. From the GPR survey, the signals filtered by the bandpass filtering are measured, and the methods consisting of gain function, time zero, background removal, deconvolution and display gain are applied to the filtered signals. As a result of application of the signal processing methods, the polarity of signal corresponds with the relation of electrical impedance of the cavity and the ground in test bed. In addition, the relative permittivity calculated by GPR signal is compared with that of predicted by volumetric water content of the test bed. The relative permittivities obtained from two different methods show similar values. Therefore, the abnormal area where the change in ground volumetric water content is occurred can be detected from the results of the GPR survey in case the depth of underground utilities is known. Signal processing methods and estimation of relative permittivity performed in this study may be effectively used to detect the abnormal area of ground in urban area.