• Journal of Powder Materials
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• v.28 no.1
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• pp.7-12
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• 2021

The change in the open porosity of bulk graphite as a function of the uniaxial molding pressure during manufacturing is studied using artificial graphite powder. Subsequently, the graphite is impregnated to determine the effect of the open porosity on the impregnation efficiency and to improve the density of the final bulk graphite. Bulk graphite is manufactured with different uniaxial molding pressures after mixing graphite powder, which is the by-product of processing the final graphite products and phenolic resin. The bulk density and open porosity are measured using the Archimedes method. The bulk density and open porosity of bulk graphite increase as the molding pressure increases. The open porosity of molded bulk graphite is 25.35% at 30 MPa and 29.84% at 300 MPa. It is confirmed that the impregnation efficiency increases when the impregnation process is performed on a specimen with large open porosity. In this study, the bulk density of bulk graphite molded at 300 MPa is 11.06% higher than that before impregnation, which is the highest reported increase. Therefore, it is expected that the higher the uniaxial pressure, the higher the density of bulk graphite.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.4
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• pp.376-390
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• 2001

Alveolar bone changes after immediate loading on implants up to one year were observed by means of standard intraoral X-ray measurement which were taken at 3 month intervals. At the same time, bone density changes were observed according to digital subtraction method which is a becoming a more and more promising diagnostic tool for implants. Following results were obtained ; 1. There was no significant difference in the amount of alveolar bone loss implant type, sex and implant diameter, but there was difference according to case selection. In fully bone anchored prostheses cases, bone loss was $1.16{\pm}0.15m$ whereas, in partial edentulous cases, it was $1.84{\pm}0.08mm$. 2. Alveolar bone loss after immediate loading showed a higher degree of bone loss than after submerged loading in the initial three months. But there were no significant difference at the 12th month. 3. According to the one year bone density change observation at the alveolar bone surrounding the implant, significant change was observed vertically, whereas no significant change could observed horizontally. According to the above mentioned results, we can conclude that immediate loading of implants results in a higher degree of alveolar bone loss in one year than submerged loading. But since alveolar bone loss rate decreases to a reasonable rate after the initial 3 months of rapid bone loss, immediate loading of implants seems to be an acceptable treatment modality for patients with good bone conditions. Fully bone anchored cases showed an favorable outcome, but partial edentulous cases showed more bony resorption. So this cases considered in case selections. Bone density changes observation in the study was performed for only one year therefore a more longitudinal observation may be studied.

• The Journal of Pediatrics of Korean Medicine
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• v.17 no.2
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• pp.1-13
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• 2003

Objectives: The purpose of this study was to suggest a scientific method for measurement of children's growth development. Ultrasonic image of calcaneus bone has some advantages that it is harmless to human body and apply a new imaging analysis algorithm. it can be used for the diagnosis of growth analyzed the opening degree of growth plate and bone density. Methods: This clinical study have been carried out with the 57 case(male 24, female 33) of the children aged 5 to 14 years old who visited in Department of Pediatrics, Dongguk university Bundang Oriental Hospital. Bone maturity is measured by the opening degree of growth plate and bone density in ultrasonic image of calcaneus bone This study were designed to investigate the relationship of the development of children and the calcaneus bone maturity. Result: The opening degree of growth plate was no change in aged 5-10 years for male and 5-9 years for female but decreased significantly from aged 11 years for male and 10 years for female. the bone density was no change in aged 5-12 years for male and 5-11 years for female but increased significantly from aged 13 years for male and 12 years for female. it was confirmed that bone maturity in female is more rapid than in male. The opening degree of growth plate of claclneus bone was correlated with age, height, weight. The bone density was correlated with age, height, weight, BMI in this suudy(P<0.001) Conclusion: The opening degree of growth plate and bone density of calcaneus bone are sufficient diagnostic worth as an index to predict adolescent growth.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.41-47
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• 1972

Comparative study on dynamic change of canopy structure during ripening period were carried out by using newly bred high yield rice cultivar (IR 667-Suwon 213) and a commercial variety, Jinhung in relation to nitrogen nutrition. The results were as follows. 1. Canopy structure pattern (vertical distribution of dry matter density at heading)was vertical type for Jinhung and horizontal type for IR 667. 2. The vertical distribution pattern of leaf area density (or weight) in the canopy was central dominant type for IR 667 while apical dominant type for Jinhung. 3. Canopy conservation pattern and percent distribution pattern of leaf area density followed the vertical distribution pattern of leaf area density. 4. Canopy persistence was weaker in IR 667, thus they have smaller canopy conservation ratio indicating faster senescence. 5. Slow supply of nitrogen (sulfur coated urea) showed a trend to change the apical dominant pattern into the central dominant pattern by the conservation of central portion, and it-resulted in higher yield though nitrogen nutrition did little affect canopy pattern. 6. The central and apical dominant pattern appeared to be well matched to the upper leaf-dependent type and the lower leaf-dependent type of grain yield, respectively.

• Journal of Korean Physical Therapy Science
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• v.15 no.2
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• pp.1-13
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• 2008

Background: This study had been carried out with 18 ischemic stroke patients as its object for about eight months from October, 2006 to May, 2007 in order to observe the recovery of motor function and the change of important blood factors according to the different quantitative exercises. Methods: Subjects were assigned randomly either experimental group (n＝19) or the control group (n＝19), when the study began the halfway on this study dropout 20 patients, and final subjects remained experimental group's 9 patients and control group's 9 patients. Both groups received thermotherapy and functional electrical stimulation (FES), also taken different quantitative exercise therapy (experimental group 180 minutes, control group 80 minutes). Subjects were assessed for upper and lower extremities motor function Fugl－Meyer Scale; FMS), blood test (white blood count; WBC, low density lipoprotein －cholesterol; LDL-C, high density lipoprotein-cholesterol; HDL-C, Troponin) during pretest, after 2 months, after 3 months. Results: The results of this study were as follows; 1. FMS has no statistically significant difference with intergroup(p>.05). But there was a statistically significant difference with each groups (p<.05). 2. WBC has no statistically significant difference with intergroup (p>.05). But there was a statistically significant difference in control group (p<.05), without experimental group (p>.05). 3. LDL-C has no statistically significant difference with intergroup (p>.05). But there was a statistically significant difference in control group (p<.05), without experimental group (p>.05). 4. HDL-C has no statistically significant difference with intergroup (p<.05). But there was a statistically significant difference with each groups (p>.05). 5. Troponin Ⅰ has no statistically significant difference with intergroup (p>.05). Also there was no statistically significant difference with each groups (p>.05). Conclusion: These findings suggest that different quantitative exercises has no effect on FMS, LDL-C, HDL-C, WBC, Troponin Ⅰ with ischemic stroke patients. But the treatment period that there's less correlation between the recovery of motor function and the different quantitative exercise, also less correlation between the change of important blood factors and the different quantitative exercises with ischemic stroke patients.

• The Korean Journal of Applied Statistics
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• v.23 no.6
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• pp.1179-1190
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• 2010

Management of the existing traffic network and understanding current traffic conditions is the most important and effective way to solve traffic congestion. This research investigates the status of Korea expressway through the Speed-Flow-Density diagram and finds the best suitable queueing model for each area. Dynamic structure in the queueing model enables us to reflect the structural change of the road in case of traffic congestion. To find the best model and estimate the parameters, we use the Newton-Raphson method. Finally, we examine the road efficiency in view of the optimal speed and density using the conditional distribution of speed and density of a S-F-D diagram.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.6
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• pp.37-42
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• 2004

It is necessary for what just keep a living body balance be devoted to it being varied with acidity serious trouble, and constitution of a study person about the density (ph) change that an alkaline ion necessary for a living body is numerical to supply a human body with number alkali by PWM voltage control. Works in the water which included the calcium (Ca), kalium (K), magnesium (Mg), natrium (Na) back who is helpful for a human body, and there is Alkaline. It is done this alkaline electrolysis to ask in order to create a number, and minerals are gathered through isolated layer (isolated special layer) to a - electrode direction, and is created. of course, prominent derelicts gather, and the acidity capital is happened, and -ion of a chlorine (Cl), phosphorus(P), sulfur (S) back is usable unfavorably in water of different use to a + electrode direction. Microprocessor was used with a - pole and a + pole with a PWM(pulse width modulation) voltage in this electrolysis process, and four kinds of PWM voltages were implemented, and a voltage every ph density change tried to be considered. It is expected by getting exactly if number alkaline ion of ph density value necessary is done with setting value if PWM control is used thus.

• Journal of Nutrition and Health
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• v.36 no.2
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• pp.175-182
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• 2003

This study was conducted to examine whether bone mineral density changes in 55 young Korean college women aged 19 to 26 years over 2 years and nutritional and biochemical factors are related. Bone mineral density (BMD) was measured in the spine (LS), femoral neck (FN), ward's triangle (WT), and femoral trochanter (FT) by dual energy X-ray absorptiometry three times at one-year intervals. Serum osteocalcin (OC), parathyroid hormone (PTH), and urinary cross-linked N-teleopeptides of type collagen (NTx) were measured. Dietary intake was assessed 8 times with 24-hour recall method. Physical activity (PA) was obtained by questionnaire and body fat content was measured by bioelectrical impedance analysis at baseline and after 2 years. Analyses were performed on 34 subjects with all three BMD measurements. The BMDs at the lumbar spine gradually increased over 2 years, while the BMDs of three sites at the femur were sustained or increased. The mean OC, PTH had a similar pattern with the change of BMD at the femur. The mean NTx decreased over 2 years but was still higher than those in other studies. BMI, body fat, vitamin A and zinc intake had a significant correlation with LS-BMD. Femur, PTH, body fat, vitamin A, vitamin B$_2$and calcium intake had a significant correlation with WT-BMD and was mostly influenced by diet. By multiple regression analysis, it was shown that the significant factors affecting the LS-BMD were BMI and vitamin A intake and those affecting FN and WT were age, BMI, PTH and calcium intake. These results indicate that some Korean women still experience increases in BMD and that this was associated with PTH and vitamin A and calcium intake. Therefore, proper diet and diet management is needed to increase changes in BMD among college women.

• Journal of Biosystems Engineering
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• v.21 no.1
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• pp.84-93
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• 1996

Several paraffins(CnH2n +2) can be used as the thermal energy storage medium because of their large amount of latent heat and their flexibility of phase change temperature. But they have not been used in the thermal energy storage system because their long term stability have not been verified. Paraffins(CnH2n+2) which the values of n are 23, 24, 26 and 28 were selected for this experimental research. And this research was peformed to apply them to the practical systems. The results were summarized as follows. (1) The increase of phase change cycles had no effect on their phase change temperatures. (2) According as the values of n increased from 23 to 28, the specific heats of paraffins(CnH2n+2) increased, and were in the range of 0.47 0.75 ㎉/$kg^circ C$. (3) Thermal conductivities of them were in the range of 0.14 0.17 W/$m^circ C$. and specific gravities of them were in the range of 765800 kg/m3. (4) The density of paraffins was in the range of 765 800 kg/$m^circ C$ , and the density of solid phase was larger than that of liquid phase. (5) When the number of phase change cycles was 1, 500 cycles, the latent heat of paraffins was 90% of the initial value.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.69-74
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• 2009

The tempering system which is developed by this research which sees energy curtailment and from the environmental side which is essential for in hazard analysis critical control point. The tempering system with development experimented frozen pork and fish. As test result, frozen pork region was not thawed occurred plentifully. Like this the actual condition, the case of frozen fish is grind and the bulk and density uniformly was formed, the pork the density was dense and was thought with the fact that the temperature difference change is big. Also after tempering from measurement location center the temperature appeared substitutionally with the low-end thing. This central part of the frozene region is thought the impedance change appears few. To hereafter respects an impedance change is thought that has the necessity which will change the structure of tempering system.