• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.30-36
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• 2012

The active fraction of soil organic matter, which includes organic debris and light organic fraction, plays a major role in nutrient cycling. In addition, particulate organic matter is a valuable index of labile soil organic matter and can reflect differences in various soil behaviors. Since soil organic matter bound to soil mineral particles has its density lower than soil minerals, we partitioned soil organic matter into debris ($<1.5g\;cm^{-3}$), light fraction ($1.5-2.0g\;cm^{-3}$), and heavy fraction ($>2.0g\;cm^{-3}$), based on high density $ZnCl_{2-}$ sucrose solutions. Generally, partitioned organic bands were clearly separated, demonstrating that the $ZnCl_{2-}$ sucrose solutions are useful for such a density gradient centrifugation. The available gradient ranges from 1.2 to $2.0g\;cm^{-3}$. Although there was not a statistically meaningful difference in organic debris and organomineral fractions among the examined soils, there was a general trend that a higher content of organic debris resulted in a higher proportion of light organomineral fraction. In addition, high clay content was associated with increased fraction of light organomineals. Partitioning of soil organic carbon revealed that carbon content is reduced in the heavy fraction than in the light fraction, reflecting that the light fraction contains more fresh and abundant carbon than the passive resistant fraction. It was also found that carbon contents in the overall organic matter, debris, light fraction, and heavy fractions may differ considerably in response to different farming practices.

• Journal of the Korean Ceramic Society
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• v.30 no.4
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• pp.289-298
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• 1993

Properties in terms of the variation of the glass compositions, which were density (p), molar volume(Vm), atom/ion packing density (Dp), refractive index (nD), transformation temperature (Tg), dilatometric softening point (Td), thermal expansion coefficient (α), Young's modulus (E), and knoop hardness (KHN) were investigated in CaO-SiO2 glasses and CaO-P2O5-SiO2 glasses containing less than 10mole% of P2O5. Those properties were measured by density measurement kit, Abbe refractometer, dilatometer, ultrasonic pulse echo equipment, and micro hardness tester. When CaO content was increased in CaO-SiO2 glasses, p, Dp, nD, Tg, Td, α, E and KHN were increased, while Vm was decreased. When P2O5 was added to the CaO-SiO2 glasses with constant CaO/SiO2 ratio as 1.07, p, Dp, nD, Tg, Td, α, E and KHN were decreased, while Vm was increased. When the amount of P2O5 in glasses was kept constant, the changes of the properties with variation of CaO content in the CaO-P2O5-SiO2 glasses were very similar to those of CaO-SiO2 glasses. These phenomena could be explained by the structural role of P2O5 in the CaO-P2O5-SiO2 glasses, which was polymerization of siicate structures and resulted in [PO4] monomer structure in glasses. Due to this structural characteristics, the bond strength and packing density were changed with compositions. Proportional relationships between 1) np and Dp, 2) Tg, Td, α and CaO content, 3) E and Vm-1, and 4) KHN and P2O5 content were evaluated in this investigation.

• Journal of Preventive Medicine and Public Health
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• v.39 no.5
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• pp.389-396
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• 2006

Objectives: A community-based, cross-sectional survey was conducted to determine theprevalence of osteoporosis and to evaluate the effects of body composition, health behaviors and reproductive history on bone density in postmenopausal women. Methods: The study subjects were 362 postmenopausal women, aged 45 years old or over, who were invited to the hospital. Information on their socio-demographic characteristics and the potential risk factors such as their past medical history, smoking, alcohol intake, exercise, diet and menstrual/reproductive histories were collected by trained interviewers. Weight, height, the body mass index ($kg/m^{2}$), and body composition variables were measured. Bone mineral density of the lumbar spine was measured by dual energy X-ray absorptiometry (DXA). Results: The prevalence of osteoporosis was 30.6% in the $45{\sim}64$ years old women, 52.5% in the elderly women aged $65{\sim}74$, and 68.7% in the women aged 75 years or over. After adjustment for the effect of potential covariates, those women in the highest 25% (4th quartile) of the lean body mass are less likely to have osteoporosis (aOR=0.31, 95% CI=0.12-0.76), compared with the lowest quartile group. More parity also had significantly detrimental effects on osteoporosis. Conclusions: These findings suggest that the prevalence of osteoporosis in postmenopausal women increased with age from 46.3% of those aged 45-64 to 68.7% for those aged 75 and over. Lean body mass and parity appeared significant contributor to bone mineral density in postmenopausal women in this population.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.3
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• pp.89-98
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• 1986

This study was carried out for the settlement and camber of earth dam by the changes of the density. The testing material was taken five kinds of Soil used as banking material and it was compacted by 100, 95, 90, 85 and 80% compaction degree. The results of the settlement of earth dam whose height ranges from 10m to 50m are as follows. 1.The more the fine particle (n) increases, the higher the liquid limit (WL) and the lower the dry density (rd) becomes as follows; rd=2. 22-0. 0052n (gr/cm$_3$) rd=2. 394-0. 0164WL rd=2. 185-(5. 8n-2. 5WL)X10-$_3$ 2. The higher the optimum moisture content (Wo) becomes, the lower the density becomes as follows; rt,=2. 68-0. 028Wo rd=2. 578-0. 04Wo 3. 3.Most of the consolidation occurs immediately by loading and the more the fine particle increases, the lower the coefficient of consolidation becomes. 4.The more the fine particle increases and lower the compaction degree (D) becomes,the lower the pre-consolidation load (Pc) becomes but on the contrary the compression index (Cc) becomes higher. Those equation is as follows. Pc=3. 32-(4. 3n-3. 0D) X10-2 (kg/cm$^2$) Cc=0. 41+(1. 33n-4. 44D) X10-$^3$ 5.The more the consolidation load (P) increases, the lower the coefficient of volume change (mv) becomes with mv=ap-b, the higher the consolidation ratio (u) becomes with U= (0. 6~1. 35)PO.4 6.The more the fine particle (n) increases, the more the settlement of dam occurs with U=anb and 60-80% of the settlement occurs under construction. 7.The camber of dam has higher value in condition that has more fine particle, poorer compaction and higher height of dam. In the dam construction about twice value of table 7 is required for dam safety.

• The Korean Journal of Food And Nutrition
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• v.20 no.4
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• pp.450-459
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• 2007

This study was performed to assess the relationships between bone mineral density(BMD), anthropometric measurements, and maternal factors in postmenopausal women. The anthropometric measurements were taken by a trained practitioner, and the maternal factors of the 85 subjects in Chungnam were acquired by an interview questionaire. The BMDs of the lumbar $spines(L_2-L_4)$, femoral necks(FN), ward's triangles(WT), and trochanters(TR) were measured by dual energy X-ray absorptiometry(DEXA). The BMDs(T-score) for $L_2-L_4$, FN, and WT were 0.996 $g/cm^2$(-1.601), 0.697 $g/cm^2(-1.657)$, and 0.793 $g/cm^2(-1.512)$ respectively, which were assessed as osteopenia by the T-score ; TR was noma1 at 0.718 $g/cm^2(-0.675)$. The 85 subjects in Chungnam were divided into three groups according to their BMD measurements for $L_2-L_4$ and FN, assessed by the T-score. The percentages in the osteoporosis, osteopenia, and normal groups were 32.9%, 42.4, and 24.7%, respectively. The average age was significantly the highest in the osteoporosis group than in the other two osteopenia and normal group(p<0.001). The subjects' BMDs were positively correlated with weight, height, BMI, waist, WHR, OBR and hip circumference, and negatively correlated with the age, duration time after menopause, lactation, the age of last delivery, menarche age, and number of children. The average age at menopause was 48.8. The osteoporosis group's average age at menopause was lower than those of the other groups. However, the BMD of the lumbar spine positively correlated with duration time after menopause and the BMD of the femoral neck with lactation, last delivery, menarch age, number of children. Therefore, researches are needed to find out the effective way to minimize the effect of age and other physiological conditions on the decrease of bone mass density.

• Journal of Korea Water Resources Association
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• v.46 no.9
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• pp.909-919
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• 2013

This study examines the hydraulic characteristics, the channel changes, the behavior of bars, and bank stability by means of laboratory experiments. Three sets of laboratory experiments are conducted to elucidate the influence of riparian vegetation of the channels with erodible banks. Flow velocity is decreased in the vegetated zone, the mobility of lower channels is decreased. The double Fourier analysis of the bed waves shows that 1-1 mode (alternate bar) is dominant at the initial stage of the channel development. As time increases, 2-2 and 2-3 modes (central or multiple bars) are dominant due to the increased width to depth ratio. As the vegetation density is increased, the number of bars are increased, bank stability increases. The variation of sediment discharges is affected by vegetation density. The braided intensity is decreased with vegetation density. As the vegetation density is increased, the correlation coefficient of bed topography and bed relief index is increased.

• Polymer(Korea)
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• v.27 no.5
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• pp.502-507
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• 2003

The thermal and physical properties of low density polyethylene melt-blended with Metallocene linear low density polyethylenes were investigated. Since the Metallocene polyethylenes have similar MW and MWD except m-LLDPE4, it can be said that the thermal behavior and mechanical properties of the blends depend upon the l-octene comonomer content. The melting behavior of LDPE/m-LLDPE1 blends shows two melting peaks with LDPE contents higher than 50%, while the other blends show only one melting peak. It was observed that the blends show higher crystallization temperature and higher crystallinity with lower comonomer content. Initial modulus of a blend exhibited the behavior proportional to the crystallinity and the elongation at break of the blends was increased with increasing the m-LLDPE composition. Melt indices of the blends decreased with increasing the comonomer content of Metallocene LLDPE. Melt Index values of the blends show negative deviation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.151-164
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• 2006

We monitored the current macrozoobenthic community structure after the Sea Prince oil spill around Keumo-do and Sori-do, Korea. Macrobenthic animals were collected seasonally around Sori-Keumo do using a van Veen grab ($0.1m^2$) from October 1999 to April 2000. In total, 196 species were identified at 46 sites around Keumho-do. The mean density was 1,460 individuals/$m^2$, and polychaetes comprised 80% of the total density of the macrozoobenthic. Dominant species were the polychaete Tharyx sp. (51%), the echinoderm Amphioplus megapomus (5%) and the polychaete Lumbrineris longifolia (3%). We identified 176 macrobenthic species at 36 sites around Sori-do. The mean density was 1,068 individuals/$m^2$, and polychaetes was the most abundant faunal group, comprising 41%, followed by mollusks (24%) and echinoderms (20%). Dominant species in Sori-do were the mollusk Potamocorbula amurensis (23%), the chinoderm Amphioplus megapomus (14%), and the polychaete Tharyx sp. (10%). The overall community structures in the study area showed few seasonal changes, although there was a gradual change in the species composition within each benthic community. Tharyx sp. was the most abundant species in the study area. Because this species has not been found in the other coastal areas except during recent investigations, it is considered to have increased during the course of community succession after the oil spill. The macrozoobenthic around Keumo-do showed little change in species richness, whereas around Sori-do, it showed a few increases in species richness after the summer of 1998. The overall density showed the same trend as species richness. Based on improved community indices, we suggest that the macrozoobenthic communities around Sori-Keumo Islands are gradually recovering from the oil-spill damagecaused by the oil spill.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.6
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• pp.710-722
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• 2014

This study investigated factors affecting the bone mineral density (BMD) of Korean adult men. Data on BMD and anthropometric (height, weight, body mass index, BMI, waist circumference, body fat) and biochemical(total cholesterol, vitamin D, alkaline phosphatase, ALP) measurements were obtained from the Fourth and Fifth Korea National Health and Nutrition Examination Surveys (KNHANES, 2008~2011). Overall, BMD of the subjects was decreased from year to year (T-score of 30~39 yr decreased to 0.447 (2010~2011) from 0.106(2008~2009) and in 50~59 yr decreased to 0.234 from 0.033. Age was negatively associated with BMD (T-score 0.361 of 20~29 yr group and -0.894 of ${\geq}80yr$ group in total femoral). According to increase of weight, BMI and waist circumference continuously increased BMD. High value of total cholesterol (T-score 0.157 of 201~<230 mg/dL group and 0.064 of ${\geq}230mg/dL$ group in total femoral) and alkaline phosphatase (T-score 0.337 of ${\leq}102IU/L$ group and -0.270 of ${\geq}336IU/L$ group in total femoral) were associated with lower BMD. Overall height, weight and BMI were positively associated with BMD, and ALP were negatively associated with BMD. Finding of the present study showed that bone loss may be associated with various factors such as age, weight, BMI, total cholesterol, vitamin D and ALP density and that much attention should be paid to bone health of adult men. Therefore, practical and systematic programs are required to improve the BMD of adult men as well as to maintain bone health.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.5
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• pp.500-511
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• 2017

This study was conducted to investigate the anthropometric data, bone density, serum profiles, nutrient intakes and diet quality of premenopausal and postmenopausal women. For the study, we obtained data for analysis from the combined 2008~2011 Korean National Health and Nutrition Examination Survey (KNHANES). The height and weight were 157.8 cm and 58.7 kg in premenopausal women and 155.5 cm and 58.3 kg in postmenopausal women, respectively. The obesity rate was 27.49% in premenopausal women and 34.98% in postmenopausal women (p<0.001). Total cholesterol, LDL-cholesterol, triglyceride, GOT, GPT and alkaline phosphatase in postmenopausal women were significantly higher than those in premenopausal women (p<0.001). The prevalence of osteoporosis was 0.0~0.89% in premenopausal women and 0.48~13.22% in postmenopausal women (p<0.001). In postmenopausal women, rates of hypertension, stroke, myocardial infarction, depression, and diabetes were significantly higher than those in premenopausal women. Water, fat. ash, sodium, retinol, thiamin, riboflavin and niacin intakes in premenopausal women were significantly higher than those in postmenopausal women. Water, fiber, Ca, and, K intakes were below KDRIs (Dietary Reference Intakes for Koreans) in both groups. The mean adequacy ratio (MAR) of premenopausal women was higher than that of postmenopausal women (p<0.001). The index of nutritional quality (INQ) in premenopausal women was also higher than that of postmenopausal women except iron and vitamin C. Therefore dietary guidelines and an education program should be developed for desirable improvement of health, bone density, nutrient status and dietary quality of postmenopausal women.