• The Journal of Korean Academy of Prosthodontics
• /
• v.29 no.1
• /
• pp.139-165
• /
• 1991

The properties of a investment material can be described by the consistency at the slurry state, the setting time, the compressive strength and the thermal expansion during the casting. In this study the effect of the production parameters which are included the ratio of quartz and cristobalite, the content of binder, the water powder ratio and the content and concentration of additives on the properties of the gypsum-bonded investments has been investigated with help of the consistency test, the vicat needle test, the compressive strength test, the thermal expansion test, x-ray diffraction and DTA thermal differential test. The experimental results showed that the constitution of a investment with W/P ratio of 0.34, 30% of gypsum, 0.8% aluminium sulfate, 2% magnesium sulfate, 0.6% sodium phosphate was adapted for the properties of the KDA Spec. No. 13 type I investment. The important experimental results are summarized as follows. 1. The consistency of the investment decreased with increasing amount of aluminium sulfate and decreasing amount of sodium phosphate. An addition of magnesium sulfate up to 2% an increase of the consistency was shown. But 3% magnesium sulfate in investment showed a decrease of consistency. The consistency did not vary significantly with a variation of the content of gypsum and cristobalite and the W/P ratio. 2. Aluminium sulfata and the magnesium sulfate promoted the hardening and the aluminium phoshpate delayed the hardening. The setting time increased with amount of gypsum. The effect of the matrix on the setting time was insignificant. With the W/P ratio of 0.34 the setting time was 14 min. 3. The compressive strength decreased with the amount of aluminium sulfate up to 0.25% and increased with the amount of aluminium sulfate greater than 3%. The compressive strength decreased as decreasing the amount of magnesium sulfate and gypsum and as increasing the W/P ratio. The effect fo the refractory on the compressive strength was also not significant. With the W/P ratio of 0.34 the compressive strength was $34Kg/mm^2$. 4. The 1st thermal expansion was found at the temperature near $250^{\circ}C$ and the steady state or the contraction stage was found at the temperature between $250^{\circ}C$ and $500^{\circ}C$. After this stage the 2nd thermal expansion took place at the temperature near $500^{\circ}C$. The amount of thermal expansion increased with decreasing the content of magnesium sulfate, aluminium sulfate and gypsum and the W/P ratio. And the amount of thermal expansion increased as the content of sodium phosphate ad cristobalite. With the W/P ratio of 0.34 the amount of total expansion was 1.2%.

• Asian Journal of Turfgrass Science
• /
• v.23 no.2
• /
• pp.271-278
• /
• 2009

This study was conducted to investigate the effect of the mixture ratio of the inorganic soil amendments on the soil physicochemical properties. In this experiment, three kinds of soil amendments which had similar pH, EC and particle size, the A, B and C, were tested. The mixture ratio of soil amendment were 0%, 3%, 5%, 7% and 10% (V/V) incorporated with sand which met to the USGA(United State of Golf Association) particle standard. To analyze the effects of amendment on chemical soil properties, pH, EC(electrical conductivity) and CEC(cation exchangeable capacity) were measured. The porosity, bulk density and hydraulic conductivity also measured to analyze the changes of physical properties. In the chemical properties, pH was significantly related to the mixture ratios of amendments, A and C(P<0.05), CEC and EC also related to the ratios of C(P<0.01). When the results were applied to the USGA standard of the soil physical properties, the optimum mixture ratios of each amendment were 3% in A and B, and 7~10% in C. To analyze the corelation of mixture ratio versus to physical character, volume of porosity was significantly related to the ratio of B (P<0.05), and showed similar corelation in porosity and hydraulic conductivity with ratio of C(P<0.05). These results indicate that types and mixture ratio of inorganic soil amendments should affect on soil physio-chemical properties of root zone on USGA sand green.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.890-895
• /
• 2003

The purpose of this experimental study is to investigate the influence of shear span-to-depth ratio on the minimum shear reinforcement ratio of reinforced concrete beams. In this study, 7 reinforced concrete beam specimens were tested. The parameters of experiment are shear span-to-depth ratio(a/d=2.0, 3.0, 4.0) and shear reinforcement ratio($p_v$=0%, 0.183%, and 0.233%). The section of all secimens was 350mm width and 450mm depth. The observed results were compared with the calculated results by the current ACI 318-02 Building Code and the proposed equation. The safety rate of the specimens, L5S2A, L5S3A, L5S4A, and L5S4P specimens were 1.80, 1.25, 1.38, and 1.56 respectively. The test results indicated that the shear behavior of reinforced concrete beams with the minimum shear reinforcement was influenced by the shear span-to-depth ratio.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.20 no.2
• /
• pp.93-100
• /
• 2010

The calcium to phosphate ratio (Ca/P) in biphasic calcium phosphates powders using X-ray diffraction analysis (XRD) was characterized. The BCP powders with various stoichiometric Ca/P molar ratio were synthesized with coprecipitation process and calcination. Compositions of the powders with Ca/P molar ratio between 1.5 and 1.67 were subjected to starting Ca/P molar ratio, pH = 10, and thermal treatment up to $900^{\circ}C$. The structural, morphological and chemical characterizations for BCP powders with stoichiometric Ca/P ratio were carried out with scanning electron microscope (SEM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) and a phase quantification was investigated by XRD. The solubility of HAp, $\beta$-TCP, and BCP powders was tested in the phosphate buffer solution (PBS) at $36.5^{\circ}C$ and pH = 7.4.

• The Korean Journal of Food And Nutrition
• /
• v.7 no.4
• /
• pp.353-360
• /
• 1994

Effect of pH, calcium, sucrose, heating and mixing ratio of soy and cow milk was studied on the viscosity and the sensory characteristics of cow-soy milk. The viscosity of soymilk was significantly affected by pH with showing maximum at 6.0 and the pH effect was decreased as the ratio of cow talk increased. A addition of sucrose or calcium affected little on the viscosity and a negative linear relationship was found be tween viscosity and an increase in cow milk ratio. Sensory characteristics of grassy and beany odor and taste of soymilk were rapidly decreased and nutty flavor and total acceptability were increased during initial 30 min of boiling. A further increase in boiling affected little on tastes and odors of soymilk. The beany odor and taste linearly decreased and milk flavor Increased as the ratio of cow milk increased. The total acceptability of 50 : 50 was found to be maximum for cow and soy mixed milks.

• Korean Journal of Poultry Science
• /
• v.28 no.3
• /
• pp.187-192
• /
• 2001

The repeatabilities on Yolk percentage and yolk to albumen (Y:A) ratio of the eggs produced consecutively were investigated. The differences between two yolk lines in major egg characteristics were also evaluated. The investigations using one hundred ISA-Brown layers were conducted at 29 wk, 33 wk, 38 wk, and 43 wk of age. At the initiated age (29 wk of age) of the experiments, the birds producing eggs with lower or higher Y:A ratio than the overall mean Y:A ratio were classified as Low Yolk Line (LYL) or High Yolk Line (HYL), respectively. Overall, the eggs of LYL were significantly (P<0.05) lighter in yolk weight and lower in yolk percentage for the whole egg weight and Y:A ratio, but heavier in egg weight, albumen weight, and shell weight than those of HYL. The overall mean correlations among the three consecutive laying days in Y:A ratio showed highly significant (P<0.001) in both lines. At four different ages, the mean phenotypic correlation coefficients (r$_{p}$) among the three consecutive laying days in Y:A ratio also had very high significant(P<0.01 ~ 0.001) positive values. The egg weight was more closely associated with albumen weight than with yolk weight in both yolk lines.s.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.2
• /
• pp.107-113
• /
• 2009

In order to improve air stability, we proposed a new active layer of an organic TFT by synthesizing P3HT/POSS conjugated polymer. P3HT/POSS OTFTs with the various P3HT/POSS volume ratios were fabricated and characterized. With the P3HT/POSS volume ratio of 1:1, we achieved the field-effect mobilities of ${\sim}1.19{\times}10^{-3}\;cm^2/v{\cdot}sec$ in the saturation region and the current on/off ratio of ${\sim}2.51{\times}10^2$. The resulting current on-off ratio was much higher than that of the P3HT-based OTFTs and resulted from the dramatic decrease of the off-current. Since the off-current can be reduced by preventing oxygen in atmosphere from doping the P3HT/POSS active layers, this new active layer shows its ability to avoid oxygen doping in atmosphere. Therefore, the improvement of the air stability can be achieved by employing the P3HT/POSS active layers.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.3
• /
• pp.353-358
• /
• 2003

Regarding the fattening of younger cattle that the Ministry of Agriculture Forestry and Fisheries (MAFF) recommends in Japan, this study looked at vitamin A control in feed and blood and its effect on performance of production and carcass composition of Wagyu steers. Five sets from 10 Wagyu artificial identical twins were divided to into 2 groups, a restricted group (Test) and a supplied group (Control). The body weight at the finishing time of the Test was significantly lower than that of the Control (p<0.05). The daily gain from 13 to 21 months old, as the animals in the Test were fed the concentrated feed without Vitamin A, was significantly different (p<0.05) between the Test and the Control. The total daily gains for the Test and the Control for the fattening period were 0.82 kg/day and 0.93 kg/day, respectively, which showed a significant difference (p<0.01). Regarding the rib thickness, the Test was thinner than the Control. The Beef Marbling Scores of the Test and Control were 3.60 and 2.80, respectively. The muscle weight of the Test was significantly smaller than that of the Control (p<0.01). However, regarding the ratio to the carcass, the Test was significantly higher than the Control (p<0.05). For the fat weight, the Test was smaller by about 15 kg than the Control (p<0.01). Furthermore, for the fat ratio to the carcass, the Test was significantly lower than the Control (p<0.05). The bone weights of the two groups were approximately the same. Regarding the ratio of bone to carcass, the Test was higher than the Control (p<0.01). For the younger fattening method, the low level vitamin A in the serum had the effect that the muscle ratio to the carcass weight was greater and the fat was less, but the carcass and muscle weight were less.

• Korean Journal of Community Nutrition
• /
• v.15 no.1
• /
• pp.27-35
• /
• 2010

This study was done to investigate the association of blood clinical parameters and dietary intakes with serum adiponectin level. Athropometric measurement, dietary intakes, serum lipids and adiponectin levels were examined in 160 overweight and obese women. The subjects were divided into 5 groups by quintile according to serum adiponectin level. Weight, BMI, waist circumferences and waist/hip ratio of the highest quintile group were significantly lower than those of the lowest quintile group. Serum lipid analysis showed a significant higher level of TG, LDL-cholesterol, LDL/HDL ratio, AI, and serum hs-CRP in the lowest quintile group. Similarly, correlation data also showed that serum adiponectin level was positively correlated with serum HDL-cholesterol level (p < 0.01) and was negatively correlated with BMI (p < 0.01), waist circumferences (p < 0.01), waist/hip ratio (p<0.01), systolic (p < 0.01) and diastolic blood pressure (p < 0.05), TG (p < 0.01), LDL-cholesterol (p < 0.05), LDL/HDL ratio (p < 0.05), AI (p < 0.01), Homa-IR (p < 0.01), hs-CRP (p < 0.05) and leptin (p < 0.05). Dietary intake data showed that protein intake was significantly lower in the highest quintile group compared to the lower quintile groups while intakes of vitamin C was significantly higher in highest quintile group after adjustment by BMI, waist and energy intake, In addition, the highest quintile group had higher fiber intakes than the lower quintile groups. These results might suggest that a diet high in fiber and vitamin C and low in protein for obese patients would better be recommended to improve adiponectin level. However, further research is needed to elucidate the association of dietary intakes or dietary patterns and serum adiponectin level.

• Journal of the East Asian Society of Dietary Life
• /
• v.18 no.6
• /
• pp.949-958
• /
• 2008

This study was carried out to examine the association of age, nutrient intake, alcohol drinking and smoking on serum lipid and apolipoprotein levels in 100 healthy adults (54 males and 46 females). The serum total cholesterol, low density lipoprotein cholesterol (LDL-C) (p<0.05), apolipoprotein B (Apo B) levels, LDL-C:high density lipoprotein cholesterol (HDL-C) ratio, Apo B:apolipoprotein(Apo A-I) ratio and atherogenic index (AI) (p<0.001) were significantly higher in males than females, but HDL-cholesterol level was significantly lower (p<0.01) in males than females. The plasma ascorbic acid concentration had no difference in both genders. Most of nutrient intakes except Ca, vitamin A and vitamin $B_2$ were higher than RI (Recommended intake) in both males and females. The meal frequency per day was significantly higher (p<0.01) in males than females, while meal speed, the heaviest meal, meal quantity and meal regularity had no significant differences. The rates of drinking and smoking were significantly higher (p<0.01) in males (59.3%, 37.2%) than females (17.3%, 6.9%). The age was positively correlated with triglyceride level in males (p<0.05), and with total cholesterol (p<0.001), LDL-cholesterol (p<0.001), Apo B (p<0.01), LDL-C:HDL-C ratio (p<0.01), Apo B:Apo A-I ratio (p<0.05) and AI (p<0.01) in females. The levels of serum lipid and apolipoprotein were more correlated with protein intake than other macronutrient intakes in males, while those in females were more correlated energy, carbohydrate and lipid intakes than protein intake. The effect of drinking on serum lipid and apolipoprotein levels was bigger in males than females, while the effect of smoking on those was bigger in females than males. The plasma ascorbic acid concentration was positively correlated with HDL-cholesterol (p<0.05), Apo A-I levels (p<0.001), whereas negatively correlated with Apo B:Apo A-I ratio (p<0.05) in males. And that was positively correlated with HDL-cholesterol (p<0.05) in females. These results suggest that moderate macronutrient intake, less alcohol consumption and non-smoking were necessary to maintain healthy lipid profile with aging in adults.