• Transactions of Materials Processing
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• v.13 no.3
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• pp.279-284
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• 2004

Electroforming is the highly specialized use of electrodeposition for the manufacture of metal parts and basically a specialized form of electroplating. So, we can apply electrochemical system analysis for electroforming process. Electrochemical systems are concerned with the interplay between electricity and chemistry, namely the measurements of electrical quantities, such as current density, potential, and charge, and their relationship to chemical parameters. This paper based on the basic equations of electrics and electrochemical kinetics, was employed for a theoretical explanation of the current density distribution on electroforming process. We calculated current density distribution and potential distribution on cathode. Also, calculated current density distribution of vertical direction. It was shown that current density is related with distance of between anode and cathode and mass transfer process.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.11
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• pp.1798-1811
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• 2010

This research evaluates the changes in the comfort-related properties of high-density fabric, such as moisture permeability and waterproofness, in order to assess the relative importance of laundry conditions for clothing properties after repeated laundering and suggest the best laundering conditions for high-density fabric through the identification of the most influential factor. A commercial high-density fabric was washed 25 times in a drum-type washer using nine different laundry conditions based on profiles derived from a fractional factorial design. To evaluate the changes in the comfort-related properties of the fabric, pore size, air permeability, water vapor transport, water repellency, and water resistance were measured. The comfort-related properties of the fabric deteriorated after repeated laundering by the damaged surface finish; in addition, the damaged surface also changed the pore size. As a result, the water repellency and water resistance decreased. The detergent was the most responsible factor to change the properties among the four factors of detergent, hardness, temperature, and RPM. The best laundering conditions for the fabric was a neutral detergent, soft water of 70ppm, a temperature of $15^{\circ}C$, and 30rpm.

• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.167-174
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• 2004

Density is a physical property which contains information relating to the internal quality of fruits and vegetables, and can be used as an index for nondestructive quality evaluation. Density sorting has been employed by farmers for some agricultural products since ancient times. In this study, an automatic density measuring system based on the platform scale or water displacement method was developed for density sorting of watermelon. It consisted of water tan, load cell, net tray, electric motor, limit switch, control system and its program. The resolution of density was 0.001 g/㎤. In order to calibrate and evaluate the accuracy, the density was measured using a balloon kept in cold water. It showed 1.002 g/㎤ which almost correspond to real density of water. Test results with 6 watermelons and 3 replications showed that the standard deviations of the dens were 0.001∼0.004 g/㎤. The relationship between density and internal quality of watermelon was investigated using the system. The densities of hollow watermelons were less than 0.950 g/㎤, it was apparent that the density of the watermelon was related to the degree of hollowness. But the soluble solid contents and internal defects could not be estimated from the density.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.2
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• pp.46-52
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• 1993

The estimation of yield for semiconductor devices requires not only establishment of critical area but also a new parameter of process defect density that contains inspection mean defect density related cleanness of manufacure process line, minimum feature size and the total number of mask process. We estimate the repaired yield of memory devide, leads the semiconductor technique, repaired by redundancy scheme in relation with defect density distribution function, and we confirm the repaired yield for different devices as this model. This shows the possibility of the yield estimation as statistical analysis for the condition of device related cleanness of manufacture process line, design and manufacture process.

• Journal of the Korean Wood Science and Technology
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• v.49 no.6
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• pp.541-549
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• 2021

This paper reports a method to evaluate the residual strength of insect-damaged radiata pine lumber, such as the screw withdrawal strength as a semi-destructive method and a compression parallel to the grain test to assess the density changes after exposure to outdoor conditions. The screw withdrawal strength test was used as a semi-destructive method to estimate the residual density of decayed lumber. A compression parallel to the grain test was applied to evaluate the residual density. Three variables, such as the screw withdrawal strength, compression parallel to the grain, and residual density, were analyzed statistically to evaluate their relationships. The relationship between the residual density and screw withdrawal strength showed a good correlation, in which the screw withdrawal strength decreased with decreasing density. The other relationship between the residual density and compression parallel to the grain was also positively correlated; the compression parallel to the grain strength decreased with decreasing density. Finally, the correlation between the three variables was statistically significant, and the mutual correlation coefficients showed a strong correlation between the three variables. Hence, these variables are closely correlated. The test results showed that the screw withdrawal strength could be used as a semi-destructive method for an in situ estimation of an existing wood structure. Moreover, the method might approximate the residual density and compression parallel to the grain if supplemented with additional data.

• Research in Community and Public Health Nursing
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• v.8 no.1
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• pp.31-44
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• 1997

The purpose of this study was to measure and determine the relationship of femoral neck and lumbar bone mineral density with their and related factors. It were measured and determined the relationships among bone mineral density, bone mineral content in the lumbar and femoral neck, muscle strength (arm, back, leg), muscle endurance, instrumental activity of daily living (IADL), quality of life, cognitive perceptual variables(self efficacy, perceived health status), age, age at menopausal period. The twenty five subjects participating in this study consisted of twelve males and thirteen females at a C-institution in Chung Buk province. The mean age of subjects was 73.64 years. The data was collected from August, 1993 to September, 1993. The data was analyzed with $x^2-test$, t-test, Correlation, multiple regression using a SPSS pc+ program. 1. The mean femoral neck bone mineral density was $0.636g/cm^2$, 66.7% of young bone mineral density, the mean lumbar($L_2-L_4$) bone mineral density was $0.807g/cm^2$, 79.86% of young bone mineral density. The mean fermoral neck bone mineral content was 2.906g and the mean lumbar bone mineral content was 36.898g. 2. The mean muscle strength was 17.14kg(grip strength), 32.05kg(back lift strength), 17.14kg (leg lift strength) and the mean muscle endurance was 9.92times. 3. Men showed a significantly higher score (p<0.01) in muscle strength and muscle endurance than women, as well as a significantly higher score on self efficacy and perceived health status(p<0.05). 4. The femur neck bone mineral density had a significant correlation(p<0.0l) with leg lift strength, back lift strength, and their was a significant correlations (p<0.05) with arm strength and muscle endurance. Lumbar ($L_2-L_2$) bone mineral density had a significant correlation(p<0.05) with muscle endurance, grip strength and IADL. 5. With the multiple regression analysis the most significant predictor for lumbar bone mineral density were IADL, the most significant predictor for femoral neck bone mineral density was leg strength. This study concluded: As the mean bone mineral density and bone mineral content were low, the aged showed osteopenia. Bone mineral density, muscle strength and IADL were correlated. The aged could pro mote muscle strength, bone mineral density and IADL through Leg Press exercise which was safe and efficient for the aged. This Leg Press exercise contributed to prevention of osteoporosis and promoted the health of the aged.

• Journal of muscle and joint health
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• v.20 no.3
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• pp.161-170
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• 2013

Purpose: This study is intended to compare musculoskeletal characteristics and Bone Mineral Density (BMD)-related factors between male and female students in a university. Methods: This descriptive study used self-report questionnaires and physical measurements to collect data. Subjects were 64 male and 67 female university students. The questionnaires asked BMD-related factors such as diet, exercise, mental health, and lifestyle. Data were analyzed using descriptive statistics, t-test, $x^2$-test, Fisher's exact test and correlation analysis. Results: The male group showed better back strength, balance, endurance, physical activity, and musculoskeletal health management than the female group. Depression and smoking rates were higher in the male group than in the female group. No difference was found in diet between the two groups. Conclusion: The results suggest to develop gender-specific strategies to increase BMD in university students.

• The korean journal of orthodontics
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• v.50 no.2
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• pp.108-119
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• 2020

Objective: The primary objective of this study was to quantitatively analyze the bone parameters (thickness and density) at four different interdental areas from the distal region of the canine to the mesial region of the second molar in the maxilla and the mandible. The secondary aim was to compare and contrast the bone parameters at these specific locations in terms of sex, growth status, and facial type. Methods: This retrospective cone-beam computed tomography (CBCT) study reviewed 290 CBCT images of patients seeking orthodontic treatment. Cortical bone thickness in millimeters (mm) and density in pixel intensity value were measured for the regions (1) between the canine and first premolar, (2) between the first and second premolars, (3) between the second premolar and first molar, and (4) between the first and second molars. At each location, the bone thickness and density were measured at distances of 2, 6, and 10 mm from the alveolar crest. Results: The sex comparison (male vs. female) in cortical bone thickness showed no significant difference (p > 0.001). The bone density in growing subjects was significantly (p < 0.001) lower than that in non-growing subjects for most locations. There was no significant difference (p > 0.001) in bone parameters in relation to facial pattern in the maxilla and mandible for most sites. Conclusions: There was no significant sex-related difference in cortical bone thickness. The buccal cortical bone density was higher in females than in males. Bone parameters were similar for subjects with hyperdivergent, hypodivergent, and normodivergent facial patterns.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.8 s.338
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• pp.1-10
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• 2005

In this paper, the explicit low density codes construction from the generalized permutation matrices related to algebra theory is investigated, and we design several Jacket inverse block matrices on the recursive formula and permutation matrices. The results show that the proposed scheme is a simple and fast way to obtain the low density codes, and we also Proved that the structured low density parity check (LDPC) codes, such as the $\pi-rotation$ LDPC codes are the low density Jacket inverse block matrices too.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.234-239
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• 2014

To study catalytic activity and hydrogen embrittlement of Pd, Pt, Ni, and Cr in fuel cell electrode, we used density-functional theory. The calculation tools based electron density give much shorter calculation time and cheap costs. Maximum of bond overlap populations of each metal are 0.6539eV for Pd-H, 0.6711eV for Pt-H, 0.6323eV for Ni-H, 0.6152eV for Cr-H. Electron density of Cr has strongest in related metals, which shows strong localization of electron, implying anti hydrogen embrittlement behaviors.