• Journal of the Korean Wood Science and Technology
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• 제42권5호
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• pp.555-562
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• 2014

Characteristics of carbonized fiberboard such as chemical materials absorption, electromagnetic shielding, and electrical and mechanical performance were determined in previous studies. The carbonized board therefore confirmed that having excellent abilities of these characteristics. In this study, the effect of density on physical properties and sound absorption properties of carbonized fiberboards at $800^{\circ}C$ were investigated for the potential use of carbonized fiberboards as a replacement of conventional sound absorbing material. The thickness of fiberboards after carbonization was reduced 49.9%, 40.7%, and 43.3% in low density fiberboard (LDF), medium density fiberboard (MDF), and high density fiberboard (HDF), respectively. Based on SEM images, porosity of carbonized fiberboard increased by carbonization due to removing adhesives. Moreover, carbonization did not destroy structure of wood fiber based on SEM results. Carbonization process influenced contraction of fiberboard. The sound absorption coefficient of carbonized low density fiberboard (c-LDF) was higher than those of carbonized medium density fiberboard (c-MDF) and carbonized high density fiberboard (c-HDF). This result was similar with original fiberboards, which indicated sound absorbing ability was not significantly changed by carbonization compared to that of original fiberboards. Therefore, the sound absorbing coefficient may depend on source, texture, and density of fiberboard rather than carbonization.

• Journal of the korean society of oceanography
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• 제34권4호
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• pp.207-213
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• 1999

Sediment physical properties (compressional wave velocity, grain density, dry bulk density, and wet bulk density) are correlated to the paleoenvironmental parameters (coarse fraction, oxygen isotope, and planktonic foraminifera fragmentation) to reveal the possible interrelationship in the latest Quaternary sediments of the Ulleung Basin, the East Sea of Korea. Laboratory determinations of physical properties and paleoenvironmental parameters have been conducted on four piston core sediments. There are slight differences in the physical properties between glacial and interglacial period sediment sections. This is due to the large fraction of coarse grains of volcanic and terrigenous sediments relative to carbonate sediments. However, dry bulk density as an indicator of carbonate abundance in pelagic environment shows higher values at the lower part of cores, reflecting deeper CCD in the glacial period. Changes in velocity also relatively parallel to those in sediment coarse fraction, number of planktonic foraminifera, and wet bulk density. Therefore, we suggest that high-resolution physical properties may be used as a valuable tool for paleoenvironmental interpretation in the Ulleung Basin.

• Journal of Biosystems Engineering
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• 제6권1호
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• pp.73-82
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• 1981

The physical properties of grain are very important for the design of handling, sorting, processing, and storage system. On the physical properties of grain, volume, bulk density, true density, specific gravity, and porosity arc the major factors affecting the thermal properties of grain. This study was conducted to determine experimentally the above physical properties of rough rice (3 Japonica-type, 3 Indica-type) and barley (covered, naked) as a function of moisture content ranged from about 10% to 25% (w.b). The results of this study are summarized as follows; 1. The volume of grain kernel increased with moisture content for both rice and barley. The volume of those grain kernel was in the range of $2.2068{\times}10^{-8}{\sim}3.3960{\times}10^{-8}m^3$ at the moisture content of 14%. 2. The bulk density of rice increased linearly with moisture content for Japonica-type rough rice and quadratically for Indica-type rough rice, but the bulk density of barley decreased linearly with moisture content. The bulk density of the grain was in the range of 501.14~689.13kg/$m^3$ at the moisture content of 14%. 3. The true density of whole grain decreased linearly with moisture content, and was in the range of 1019.49~1139.75kg/$m^3$ at the moisture content of 14%. 4. The porosity of rice decreased linearly with moisture content for Japonica-type rough rice and quadratically for Indica-type rough rice, but the porosity of barley increased linearly with moisture content. The porosity of the grain was in the range of 39.51~50.83% at the moisture content of 14%. 5. The regression equations of the physical properties such as volume, bulk density, true density, and porosity of the grain were determined as a function of moisture content.

• The Journal of Korean Physical Therapy
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• 제10권2호
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• pp.97-104
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• 1998

The Purpose of this study was ta investigate the change of bone density by Partial weight bearing and non-weight bearing exercise. Twelve female volunteers in good health (between 20 and 30 years of age) were studied as subjects. Subjects were divided into three groups; an experimental group 1(n =4 swimming group), group 2(n = 4 bicycle group) and control group=4. Before and after 11weeks(five times a week), the subjects were examined for change of bond density using a dual energy X-ray absorptiometry. The results were summarized as fellows T . There was increase in bone density of femoral neck in the group that swam but there was no difference in lumbar, femoral neck and femoral ward's triangle region (P<0.05) 2. There was increase in hone density of femoral ward's triangle in the group that swam but there was no difference in lumbar, femoral neck and femoral ward's triangle region(P<0.05) 3. After a aerobic exercise by partial weight bearing and non-weight bearing , there was no difference in the part of excessive muscle's exercise but there is the increase of the bone density in figures.

• 대한물리치료과학회지
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• 제8권2호
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• pp.1015-1021
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• 2001

Objectives: The objective of this study was to investigate analysis of women with low back pain and osteoporosis were measured for 40 normal in the women from July 20, 2000 to October 20, 2000. Methods: Bone mineral density(BMD) of lumbar spine was measured using energy absorptiometry and were correlated with age, calcium. alkaline phosphatase. bone mineral density standard T scores(p<0.05). Results: The bone mineral density of the lumbar spine decreased with aging, The bone mineral density of the lumbar spine decreased with the serum calcium and phosphate increased. The mean bone mineral density of the lumbar spine of healthy women in age($50\sim59$) was $0.83g/cm^2$, the lumbar spine of women low back pain in age($50\sim59$) was 0.75 glad. Conclusion: In the multiple regression of risk factors to bone mineral density(BMD) of lumbar spine were correlated with age, of abortion, calcium, bone mineral density standard T scores(p<0,05). In the prevention and early diagnosis and treatment of osteoporosis, the physician should consider the risk factors.

• Journal of Yeungnam Medical Science
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• 제13권2호
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• pp.261-271
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• 1996

저자들은 1992년 1월 1일부터 1995년 6월 30일까지 영남대학병원에서 양에너지 방사선 골밀도 측정기로 요추 골밀도를 측정한 자연적 폐경기 여성 136명을 대상으로 설문과 의무기록지를 검토하여 연령, 신장, 체중, 초경 및 폐경 연령, 자녀수, 모유수유 자녀수, 경구 피임력, 골다공증의 가족력, 우유 및 커피섭취량, 흡연 및 음주력 그리고 신체활동량을 평가하였다. 평균 연령은 55.2세였고, 평균 폐경 연령은 47.9세였다. 골밀도는 신장, 체중 그리고 신체활동량과 유의한 양의 상관관계를 보였고, 나이, 폐경 후 기간 그리고 자녀수와는 유의한 음의 상관관계를 보였다. % age-matched 골밀도는 나이, 신장, 체중, 신체활동량 그리고 폐경 후 기간과 유의한 상관관계를 보였다. 골밀도를 종속변수로 한 다중회귀분석에서는, 폐경 후 기간, 신체활동량 그리고 체중이 골밀도에 영향을 주는 유의한 변수였고, 그 중 폐경 후 기간이 가장 영향을 주는 변수였다. 나이의 효과를 통제하기 위해 % age-matched 골밀도를 종속변수로 한 다중회귀분석에서는, 신체활동량과 체중이 % age-matched 골밀도에 영향을 주는 유의한 변수였고, 신체활동량이 가장 영향을 주는 변수였다. 그 결과 폐경기 여성의 골밀도에 영향을 미치는 인자들 중 나이의 영향을 배제하면 신체활동량과 체중이 중요한 인자로 생각된다. 그러므로 지속적인 신체활동이 골다공증의 예방에 중요하다는 것을 알 수 있었다.

• The Journal of Korean Physical Therapy
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• 제18권1호
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• pp.83-94
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• 2006

Purpose: This study conducts quantitative evaluation or structural and functional characteristics or normal skeletal muscle with ultrasound image and surface electromyography, and is to provide basic materials for utilizing ultrasound image analysis in physical therapy diagnosis and assessment of skeletal muscle. Methods: Measurement of three stages was conducted with 88 normal adults between their twenties and seventies, correlations and differences using collected data according to age and gender were compared and correlations among measured items were analyzed and then the following conclusions were obtained. Results: Analysis of ultrasound image of normal skeletal muscle showed that density, median frequency had the closest relations with age. In addition, it was found that there were high correlations between density explaining structural characteristics of skeletal muscle and median frequency explaining functional characteristics. Conclusion: Analysis of ultrasound image makes complex evaluation of structure and function of skeletal muscle possible when it is connected with functional evaluation method using physical measurement surface electromyography as well as quantitative evaluation of structural changes of skeletal muscle and is effective in complementing physical therapy diagnosis centering around functionality evaluation.

• The Journal of Korean Physical Therapy
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• 제13권1호
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• pp.97-105
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• 2001

본 연구는 2000년 7월 14일부터 8월 24일까지 대구광역시에 소재한 가톨릭병원 건강검진센타에서 골다공증 검사를 시행한 여성 36명을 대상으로 폐경후 여성의 골밀도차이를 비교하기 위해 실시하였다. 연령의 증가에 따라 요추부의 평균골밀도는 감소되었고, 신장이 증가할수록, 교육수준이 높을수록 평균골밀도는 증가했으며, 독신(이혼, 사별, 별거), 활동적인 직업 , 요통이 없다, 육류의 항목에서 평균골밀도는 각각 증가했지만 유의한 차이는 없었다. 골밀도의 표준편차인 T 값은 -2.5이하의 골다공증군이 41.7%로 가장 많았고, 골밀도 (BMD)는 평균 0.77g/c$m^2$로 나타났다. 가족중 골절시 연령이 증가할수록, 운동횟수, 운동시간이 증가할수록, 분만횟수가 증가할수록, 각각 골밀도는 높게 나타났지만 유의한 차이는 없었다. 자궁 절제술은 안했다가, 혈액형은 A형의 항목에서 골밀도는 높게 나타났지만 유의한 차이는 없었다. 폐경후 골밀도에 영향을 미치는 관련성이 있는 요인은 골밀도의 표준편차인 T 값이다(p<0.05). 본 연구는 폐경후 적성의 골밀도 관련요인에 대한 많은 변수를 고려한 전향적인 연구가 필요할 것으로 사료된다.

• Journal of the Korean Wood Science and Technology
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• 제27권4호
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• pp.57-64
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• 1999

This research was carried out to investigate the effects of density, resin and particle types on the physical and mechanical properties of the composites made from various wood particles mixed with coating paper. The experiment was designed to apply with three particles (flake, chip, and fiber) and three resin types (urea, phenol and PMDI resin). The mixed ratio of coating paper to wood particle was fixed on 50 to 50% in each board making. And also it was designed to apply for four density levels (0.6, 0.7, 0.8 and 0.9 g/$cm^3$) and four mixed formulations of coating paper to wood particle (10:90, 20:80, 30:70, and 40:60 %) to analyze clearly the effects of PMDI resin. Coating paper-wood particle composites have acceptable bending strength (MOR, MOE) though the mixed ratio of coating paper was increased, but have low internal bond strength and poor dimensional stability (WA, TS, LE). Composites with high density had higher mechanical properties but showed lower physical properties than composites with low density. In conclusion, at least up to 20% mixed ratios, coating paper-wood particle composites have acceptable physical and mechanical properties, and PMDI resin has possibility for coating paper-wood particle composite manufacture.

• Journal of the korean society of oceanography
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• 제38권4호
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• pp.166-172
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• 2003

Multi­Sensor Core Logger (MSCL) is a useful system for logging the physical properties (compressional wave velocity, wet bulk density, fractional porosity, magnetic susceptibility and/or natural gamma radiation) of marine sediments through scanning of whole cores in a nondestructive fashion. But MSCL has a number of problems that can lead to spurious results depending on the various factors such as core slumping, gas expansion, mechanical stretching, and the thickness variation of core liner and sediment. For the verification of MSCL data, compressional wave velocity, wet bulk density, and porosity were measured on discrete samples by Hamilton Frame and Gravimetric method, respectively. Acoustic impedance was also calculated. Physical property data (velocity, wet bulk density, and impedance) logged by MSCL were slightly larger than those of discrete sample, and porosity is reverse. Average difference between MSCL and discrete sample at both sites is relatively small such as 22­24 m/s in velocity, $0.02­-0.08\;g/\textrm{cm}^3$ in wet bulk density, and 2.5­2.7% in porosity. The values also show systematic variation with sediment depth. A variety of factors are probably responsible for the differences including instrument error, various measurement method, sediment disturbance, and accuracy of calibration. Therefore, MSCL can be effectively used to collect physical property data with high resolution and quality, if the calibration is accurately completed.