• Tunnel and Underground Space
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• v.33 no.3
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• pp.126-140
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• 2023

In this study, the cause of subsidence in limestone mine was analyzed using a LiDAR-based geometry model. Using UAV and ground-based LiDAR systems, a precise geometry model was constructed for the subsidence surface and mine tunnel, and the results of on-site geological survey and rock mass classification were utilized. Through the geometry model, distribution of thickness of crown pillar and faults around the subsidence area, calculation of the volume of the subsidence area and subsidence deposit, and analysis of the subsidence surface inclination were conducted. Through these analyzes, the causes of ground subsidence were identified.

• Analytical Science and Technology
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• v.21 no.1
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• pp.9-13
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• 2008

We have collected a batch of leaf samples at several main crossroads in Daejeon and a background site to obtain distribution of $CO_2$ (greenhouse gas) due to fossil fuel combustion. The leaf samples were treated with AAA method and ${\Delta}^{14}C$ values of them were measured using AMS. ${\Delta}^{14}C$ values of downtown sites were found to be lower by 27-102 ‰ than that of the background site, and the ratio of $CO_2$ originated from fossil fuel combustion in the atmosphere of Daejeon could be calculated from the differences of ${\Delta}^{14}C$ values. The average ${\Delta}^{14}C$ of the background site, around Kyeryong mountain, was measured to be $35{\pm}8$ ‰, and this value is lower than 66.3 ‰, which have been known as the backgdound values in USA.

• The Korean Journal of Ecology
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• v.23 no.1
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• pp.33-37
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• 2000

Mass loss and changes of mineral nutrients during decomposition of Lepista nuda for 7 weeks from October 7 to December 28 in 1998 were investigated in an oak stand in Kongju, Korea. Content of nitrogen, phosphorus, potassium, calcium and magnesium of the fresh L. nuda was 67.8, 4.1, 47.3, 0.4 and 1.5 ㎎/g, respectively. Content of nitrogen, phosphorus and potassium in L. nuda were much higher than those in leaf litter. After 7 weeks, remaining mass was 35%. Nitrogen, phos- phorus and potassium increased till 5 weeks and then decreased rapidly, however, calcium and magnesium steadily increased during the experimental period. Nitrogen and phosphorus showed a short period of immobilization, and calcium showed no immobilization period during decomposition. After 7 weeks, remaining N, P, K, Ca and Mg was 26.6, 37.5, 28.5, 35.0 and 91.0% of the initial content, respectively. Nutrients could be relocated spatially during the formation and decomposition of fruiting body of Basidiomycetes.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.803-813
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• 2017

This study discussed the possible optimization of enzyme-mediated calcite precipitation (EMCP) as a soil-improvement technique. Magnesium chloride was added to the injection solution to delay the reaction rate and to improve the homogenous distribution of precipitated minerals within soil sample. Soil specimens were prepared in 1-m PVC cylinders and treated with the obtained solutions composed of urease, urea, calcium, and magnesium chloride, and the mineral distribution within the sand specimens was examined. The effects of the precipitated minerals on the mechanical and hydraulic properties were evaluated by unconfined compressive strength (UCS) and permeability tests, respectively. The addition of magnesium was found to be effective in delaying the reaction rate by more than one hour. The uniform distribution of the precipitated minerals within a 1-m sand column was obtained when 0.1 mol/L and 0.4 mol/L of magnesium and calcium, respectively, were injected. The strength increased gradually as the mineral content was further increased. The permeability test results showed that the hydraulic conductivity was approximately constant in the presence of a 6% mineral mass. Thus, it was revealed that it is possible to control the strength of treated sand by adjusting the amount of precipitated minerals.

• The Journal of Pediatrics of Korean Medicine
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• v.21 no.2
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• pp.51-67
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• 2007

Objectives The study was designed to find out the relationships between short stature and low weight among children and teenagers. Methods This research was performed in 21 children and teenagers from August 2006 to June 2007. We measured height, weight, body mass index, obesity rare, bone age, and HTMA. Moreover, we analyzed correlation with height, weight, mineral concentrations and ratios obtained from HTMA. Results There were significant correlations between HTMA and short stature and low weight. 1. Most subjects(76%) had slow metabolic types. 2. Ca, Mg, Zn, Ca/P, and Cr had significant differences between high bone age group and high chronological age group. 3. Fe/Cu had significant differences between a group that recent height is more smaller than inherited height and a group that recent height is more taller than inherited height. 4. Ca, Mg, Ca/P had significant differences between a low weight group and a normal weight group classified by obesity rate. Conclusions Children and teenagers with short stature and low weight have specific mineral characters.

• Women's Health Nursing
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• v.19 no.1
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• pp.57-65
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• 2013

Purpose: This study identified the effects of body weight control behaviors on bone mineral density (BMD) in Korean women aged 20 to 39 years. Methods: A secondary analysis of the 5th Korean National Health and Nutrition Examination Survey was conducted. Asian-Pacific criteria of BMI (Body Mass Index) and BMD were calculated for 1,026 women selected. The effects of body weight control behaviors were assessed using binary multiple logistic regression analysis while controlling for BMI. Results: Osteopenia and osteoporosis rates were 32.8% and 2.0%, respectively. About 69% of women performed weight control behaviors, and a combination of diet/exercise (22.7%) and drug added methods (10.9%) for weight control. Women who performed both diet control and exercise had a lower possibility to have abnormal BMD than those who did not try weight control (OR=0.67, CI=0.45~0.98, p=.039). Further weight control behaviors did not influence abnormal BMD. Conclusion: Body weight control should include proper diet and exercise in accordance with each woman's BMI level.

• Journal of Nutrition and Health
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• v.31 no.4
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• pp.716-728
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• 1998

To investigate the effect of dietary Ca levels on metabolic changes of Ca and skeleton in postmenopausal women, 10-month-old ovariectomized female rats were compared with 2 month old rats. The rats were fed either 0.2% or 1.2% Ca diets for 16 weeks. Food intake and weight gain as higher in rats fed high Ca diets and in ovariectomized rats. Apparent Ca absorption as higher, and Ca balance was lower in the low Ca groups. Vertebrae density was higher in old rats or those fed a high Ca diets. The old rats and ovariectomized rats showed decreased bone formation, increased bone resorption and kidney function deterioration resulting in increased urinary Ca excretion. Contradictory to the above observation, old rats and ovariectomized rats still showed higher bone mass and bone ash content. Therefore aging was not fully onging in 10-month-old rats. Bone weights, mineral contents, and mineral/wt ratio were lower in ovariectomized rats. Dietary Ca level did not affect urinary Ca excretion, urinary protein excretion, GFR, serum alkaline phosphatase, or urinary hydroxyporline excretion. This means that dietary Ca level did not influence kidney function or bone turnover. However Ca content and the ash content of femur, 4th vertebra, and scapula were increased in high Ca groups. Therefore, it is considered that decreased bone formation and accelerated bone resorption may account for the increased osteoporotic risk in women in menopause after middle age. However, Ca metabolism can be improved and bone components can be maintained if Ca is supplemented.

• Women's Health Nursing
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• v.21 no.1
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• pp.43-54
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• 2015

Purpose: This study was conducted to identify the problem of bone health and potential influencing factors of bone mineral density (BMD) for women across the life cycle of menopause. Methods: Complex sampling design data analysis was performed on the fifth Korea National Health and Nutrition Examination Survey 2010 in order to identify the problems with bone health, BMD and its influencing factors in 3,499 women who answered the menopausal status. Women's life cycle was categorized by premenopausal, postmenopausal, and elderly. Results: 35.1% of premenopausal women, 73.3% of postmenopausal women, and 96.0% of elderly women had problems with bone health that were related to low BMD. Influencing factors of BMD were residential area, alcohol drinking, and body mass index (BMI) for premenopausal women; age, residential area, education, marital status, income, and BMI for postmenopausal women; and age, education, and BMI for elderly women. Conclusion: Problems with bone health required to be considered as a major health problem in all women regardless their life cycle. Interventions to maximize BMD need to be developed by considering its influencingfactors across the women's life cycle.

• Journal of Nutrition and Health
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• v.25 no.7
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• pp.656-667
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• 1992

This study was designed to investigate the effect of environmental an d physiological factors on bone mineral density(BMD) of the lumbar spine(L2longrightarrowL4) in 41 postmenopausal women. There were a positive relationships between BMD of the lumbar spine and monthly income food expenses pocket money energy expenditure(EXP) per day sociocultural EXP activity intensity time of standing and walking or age at first pregnancy. BMD of the lumbar spine was negatively correlated with age Engel index time of sleeping and sitting number of childbirty and children period of breastfeeding or menopausal period. But there were no significant relationships between BMD and physiological domestic EXP body mass index age at menar-che menstruation cycle or age at menopause. The complex interrelations between BMD and these variables were examined using stepwise multiple regression analysis. From this analysis in subject aged 50~59 years. EXP per body weight physiological EXP age at menopause time of sleeping were positively significant independent predictors of BMD. In subjects aged 60~69 years, . time of walking only and in total subjects. EXP per body weight pocket money were positively significant independent predictors ofBMD. This study suggest that EXP and pocket money are major constituents affection lumbar spine BMD in postmenopausal women.

• Journal of Korean Public Health Nursing
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• v.25 no.2
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• pp.266-275
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• 2011

Purpose: The study investigated the relationship of health behavior with bone mineral density (BMD) for college students. Methods: A descriptive study was done using a convenient sampling of college students (n=116) enrolled in a health-related department. Height, weight, body mass index (BMI), health behaviors recognition of subjective health, smoking, drinking, exercise, food habits, intake of calcium, and family history of fracture were measured. BMD was measured at the right forearm using Hologic lunar duel-energy X-ray absorptiometry. Data were analyzed using descriptive analysis, t-test, ANOVA and multiple linear regression. Results: The prevalence of osteopenia and osteoporosis was 41.4% and 22.4%, respectively. Significant relationships were observed between BMD of right forearm and gender, BMI, subjective health recognition, drinking, and exercise (p<.05). Results of linear regression after adjusted BMD were increased concerning subjective health recognition and regular exercise (p<.05). Conclusions: Subjective health recognition and exercise carries positive effects on BMD. We recommend for college students that healthy behaviors like proper weight, smoking cessation, regular exercise, regular food habits, and health awareness are helpful to BMD.