• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.167-189
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• 1992

Frictional heat produced by cutting tools during dental implantation procedure may destroy the surrounding bone tissue and regenerative capacity and interfere ossointegration by formation of undifferentiated connective tissue. To study the effect of frictional heat according to various rotational speeds on the regenerative capacity of surrounding bone tissue, 13 ITI HS implants (8 mm) were inserted at 4 mongrel dogs. Temperatures were measured using thermocouple located 6 mm below from the marginal crest and 0.5 mm from the periphery of trephine mill during implant bed preparation. After 4 and 9 months, animals were sacrificed and specimens were examined using x-rays and light microscope. Results were as follows: 1. With drill speeds of 300, 800, 2,000, 3,500 rpm and saline irrigation, temperatures of surrounding bone were decreased from $-2.9^{\circ}\;to\;-1.7^{\circ}C$. Temperature rises of $2.0^{\circ}\;and\;2.1^{\circ}C$ were recorded with a drill speed of 5,000 rpm and irrigation. 2. With drill speeds of 800, 3,500, 5,000 rpm and no irrigation, temperatures of surrounding bone rose from $+1.5^{\circ}\;to\;+6.8^{\circ}C$, but maximum temperature was $40^{\circ}C$ at 5,000 rpm. 3. On radiographic examination, bone resorptions were observed at the upper half of implant of 5,000 rpm without irrigation and one case of 5,000 rpm with irrigation. 4. Osseointegration was unsuccessful in cases of 3,500, 5,000 rpm without irrigation due to fibrous connective tissue formation to the outer surface and hollow, but it was successful in a case of 800 rpm without irrigation. 5. Osseointegration was successful in cases of 300, 800, 2,000 and 3,500 rpm with irrigation. But fibrous connective tissue formation was observed at the hollow of implant inserted with 5,000 rpm with irrigation.

• KSBB Journal
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• v.31 no.1
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• pp.20-26
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• 2016

This study aims to examine the optimum blanching conditions as a pretreatment condition to improve the storage stability of Dolsan leaf mustard pickle. The effects of the blan- ching temperature and time were investigated at a temperature range of $80-100^{\circ}C$. Sampling was done for 1 month after a 5 days interval. The L value of the Dolsan leaf mustard was found to be the highest at $80^{\circ}C$. The cutting force increased as the blanching temperature increased. The tensile strength decreased at $95^{\circ}C$ and $100^{\circ}C$. In addition, the sensory evaluation scores were the best at $80^{\circ}C$. The storage stability was assessed at various blanching temperatures to increase the sinigrin content during storage. Liquid chromatography with photodiode array and tandem mass spectrometry (LC-PDA/MS/MS) analysis was conducted to identify and quantify the sinigrin content in the Dolsan leaf mustard. Sinigrin as an internal standard was co-injected into each sample solution. The sample was monitored by recording the ultraviolet absorbance at 228 nm and by electrospray ionization (ESI) positive ion mode in the m/z 50-1,500 range. Blanching the sample at $80^{\circ}C$ showed the highest sinigrin concentration during storage among various temperatures and the maximum concentration was 350 ppm at 15 days storage. Study on utilization of vegetable from food processing of leaf mustard and preservation conservation results suggest that blanching at $80^{\circ}C$ is expected to improve the palatability of the pickle.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.2
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• pp.77-84
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• 1992

This experiment was designed to gain information on factors affecting stubble death of orchardgrass (Dactylis glomerata L.) during the first rainy season. According to the experimental plan, the effects of sowing methods, drainages and cutting dates on the stubble carbohydrate content of orchardgrass, available soil moisture content of experimental plots, temperatures at the ground level and in the soil, and relative light intensity and humidity at the base of orchardgrass canopy were measured during the rainy season. The carbohydrate content of orchardgrass was sharply decreased to 2.9 % at 3rd day after cutting in the plots cut before rainy season and a gradural recovery was noted following the sharp reduction, but in the plots cut after rainy season, orchardgrass showed 5.5% of carbohydrate content before cutting and 3.0% at the 3rd day after cutting. The same pattern in both carbohydrate reduction and recovery was found between two cutting treatments. The available soil moisture content in the plots cut before rainy season was slightly higher than that in the plots cut after rainy season. But after the rainy season, the available soil moisture content in the plots cut after rainy season was higher than that in the plots cut before rainy season. Soil temperature at lOcm depths in the plots cut before rainy season was higher than that in the plots cut after rainy season. Daily maximum air temperature at the ground level in the plots cut before rainy season was higher than that in the plots cut after rainy season and changeable. Relative humidity at the ground level was below 70% in the plots cut before rainy season, but 75 to 90 % was observed in the plots cut after rainy season. Relative light intensity at the ground level in the plots cut before rainy season was much higher, recorded 50 to 90 %, than that in the plots cut after rainy season showing less than 10%. The results of this study suggest that the stubble death of orchardgrass during the rainy season is due to plant diseases influenced by a decrease of light penetration and increase of relative humidity at the base of the grass canopy.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.768-776
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• 2010

This study was conducted to predict number and fresh weight of leaves, and total leaf area of a single-stemmed rose 'Vital' based on the accumulated thermal units, and to develop a model of shoot development for the prediction of the time when the flowering shoot reaches a phenological stage in a plant factory system. The base temperature ($T_b$), optimum temperature ($T_{opt}$), and maximum temperature ($T_{max}$) were estimated by regressing the rate of shoot development against the temperature gradient. The rate of shoot development ($R$, $d^{-1}$) for the phase from cutting to bud break (CT-BB) was best described by a linear model $R_b$ ($d^{-1}$) = -0.0089 + $0.0016{\cdot}temp$. The rate of shoot development for the phase from bud break to harvest (BB-HV) was fitted to the parabolic model $R_h$ ($d^{-1}$) = $-0.0001{\cdot}temp^2$ + $0.0054{\cdot}temp$ - 0.0484. The $T_b$, $T_{opt}$, and $T_{max}$ values were 5.56, 27.0, and $42.7^{\circ}C$, respectively. The $T_b$ value was used in the thermal unit computations for the shoot development. Number of leaves, leaf area (LA), and leaf fresh weight showed sigmoidal curves regardless of the cut time. The shoot development and leaf area model was described as a sigmoidal function using thermal units. Leaf area was described as LA = 578.7 $[1+(thermal units/956.1)^{-8.54}]^{-1}$. Estimated and observed shoot length and leaf fresh weight showed a reasonably good fit with 1.060 ($R^2=0.976^{***}$) and 1.043 ($R^2=0.955^{***}$), respectively. The average thermal units required from cutting to transplant and from transplant to harvest stages were $426{\pm}42^{\circ}C{\cdot}d$ and $783{\pm}24^{\circ}C{\cdot}d$, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.66-71
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• 1982

Field experiments of nitrogen application (0, 100, 200, 400, 800kg N/ha year) were carried out to study the nitrogen response of Sudangrass at College Farm, Seoul National Univ., in 1979 and 1980. Dry matter yield and leaf area index increased up to 400kg N/ha in 1979 and 800kg N/ha in 1980. The forage yield of 1980 was less than that of 1979, due to the extraordinarily low temperature and the decreased solar radiation during summer. Total nitrogen contents in forage increased with nitrogen application, but maximum contents were found either 400 or 800kg N levels depend on each cutting stages. Nitrate nitrogen content in forage exceded over 2000 ppm at 800kg N application. Overall percentages of N recovery were below 50% with average 34%. Net assimilation rate and nitrogen use efficiency of Sudangrass were improved in higher temperature and more sunlight condition during regrowth period.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.427-435
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• 1984

Alfalfa field was established to investigate seasonal changes of nodule activity and contents of carbohydrates, and nitrogen, and also to examine their relationships in alfalfa (Medicago sativa L.). Periodical sampling of alfalfa in cutting and uncutting plots was collected to measure growth of plants, development and activity of nodule, and content of carbohydrates and nitrogen in the third year following year of establishment. Nodule activity of alfalfa root appeared to early April, increased to a maximum in beginning of June (flowering stage), and then decreased and generally remained low from late-July to mid-August, and again increased from early September, and then decreased and generally remained low for the rest of growing season. After flowering, nodule weight tended to decrease slowly throughout the growing season. Until flowering stage, increase of dry weight was closely related with that of nodule activity. But after flowering the curve pattern of dry weight did not fit to that of nodule activity due to decrease of supply of assimilate to nodule, drought, and high temperature. Total nonstructural carbohydrates in roots were closely correlated with nodule weight and nodule activity. While, nitrogen contents in leaves were closely correlated with nodule weight and nodule activity. Also cutting on July prevented unnessesary losses of respiration during summer to provide rapid recovery of nodule activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.796-803
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• 1996

Gamma irradiation was applied to soybean(Glycine max.), Hwangkeum, at dose levels of 0, 5, 10 and 20 kGy to improve the physical properties of soybeans. The time to reach a fixed moisture content was reduced depending on the increment of soaking temperatures and applied irradiation dose levels. Irradiation at 5~20 kGy resulted in reduction in soaking time of the soybeans by about 3~6 hrs at soaking temperature of $20^{\circ}C.$ The degree of cooking of soybeans in boiling water was determined by measuring the maximum cutting force of cotyledon. The cutting force to reach complete cooking was about 145g/g. Irradiation at 5~20 kGy resulted in a reduction of cooking time of soybeans by 55~75% as compared to the nonirradiated soybean. In electron microscopic observation of seed coat inner, the parenchyma of nonirradiated soybean showed tight fibrillar structure, whereas that of irradiated soybeans showed loosened and deformed structure. The microstructure of compressed cells and cotyledon epidermis was also deformed by gamma irradiation. In subcellular structure of cotyledon, the roundness of protein body was deformed and changed to spike shape at 20 kGy. Also, the size of lipid body decreased as the irradiation dose levels increased.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1303-1312
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• 2013

We report an ultra-precision lathe designed to machine micron-scale features on a large-area roll mold. The lathe can machine rolls up to 600 mm in diameter and 2,500 mm in length. All axes use hydrostatic oil bearings to exploit the high-precision, stiffness, and damping characteristics. The headstock spindle and rotary tooling table are driven by frameless direct drive motors, while coreless linear motors are used for the two linear axes. Finite element method modeling reveals that the effects of structural deformation on the machining accuracy are less than $1{\mu}m$. The results of thermal testing show that the maximum temperature rise at the spindle outer surface is approximately $0.5^{\circ}C$. Finally, performance evaluations of the error motion, micro-positioning capability, and fine-pitch machining demonstrate that the lathe is capable of producing optical-quality surfaces with micron-scale patterns with feature sizes as small as $20{\mu}m$ on a large-area roll mold.

• Journal of Korean Society of Forest Science
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• v.38 no.1
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• pp.27-32
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• 1978

The diurnal pattern of leaf water potential in cuttings by Dye Method was as follows: 1. Diurnal pattern of leaf water potential (${\psi}_l$) in Viburnum Awabuki K. Koch and Daphne odora Thunb. was shown the pattern of the curves without mutual relation with soil classes when soil water potential (${\psi}_s$) was 0 bar. When ${\psi}_s$ was above -0.01 bar, the cuttings in the loamy sand (L.S.) was shown by the maximum values than that in sandy clay (S.C.) by about -1 bar gap (Fig. 1). 2. The diurnal changes of ${\psi}_l$ was shown the most high from two to eight O'clock in the morning, the maximum value was -3 bars when ${\psi}_s$ was above -0.01 to -0.02 bar, and was -4 bars below -0.03 bar. The diurnal the lowest values of ${\psi}_l$ showed -20 to -22 bars from one to two O'clock in the afternoon. In the fifteenth day after cutting V.A., the staying time in the diurnal maximum values of ${\psi}_l$ is about half in comparison with it in the fifth day. The curves of recovery of water stress (Fig. 1), the former reached to the diurnal maximum values -1 to -2 bars lately every hours comparing with it of the latter. The general diurnal pattern of ${\psi}_l$ was most clearly related to change with air temperature and the relative humitidy. 3. Comparing the treatment block by IAA 50 ppm with controlled block in fifteenth day after V.A. cuttings, in case of treatment reached to maximum values -2 to -3 bars lately as shown Fig. 2., and also staying times was only half in comparison with controlled block. 4. The cuttings 4 leafs was much rootings than 2 leafs in V.A. (Table. 1), and the former reached maximum value -2 to -3 bars lately every hours comparing with the latter. 5. In case of Buxus microphylla var. Koreana as shown Fig. 3., comparing the pattern curves of in the cuttings 8 leafs with 4 leafs, the former reached to maximum values -2 to -3 bars lately in comparison with the latter, but reffering to the amount of rooting (Table. 2), the former is less than the latter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.398-402
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• 1989

Moisture sorption and cooking properties of two varieties of Korean soybean(Jangyup and Whangkeum) were studied. When soybean was stored under the various relative humidities (RH) of 33-86% at 16'E for 125hours, its sorption behaviors were divided into two : desorption at the RHs of 33 and 44% and adsorption at the RHs of above 55%. The sorption rate was decreased rapidly during storage. In comparisons with only storage humidities, the sample stored at higher RH held the higher sorption rate. The relationships between storage time and sorption rate were applied well to the equation, log dw/dt= b log t+ log a, where w is the moisture content(%, db), t is time(hour) and a and b are the parameters which were calculated from the experimental data. The calculated moisture contents from the equation agreed well with the measured moisture contents. On the other hand, the cooking degrees of soybean which was steamed in an autoclave at $106-121^{\circ}C$ were compared by the maximum cutting forces. The cooking time to attain the same degree of cooking decreased logarithmically as the cooking temperature increased. The z-values which were calculated from the time-temperature combinations that gave the same degree of cooking for Jangyup and Whangkeum were $13.3^{\circ}C$ and $12.8^{\circ}C$ respectively.