• International journal of advanced smart convergence
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• 제11권3호
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• pp.170-178
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• 2022

Purpose: Gardening has been reported to have positive emotional and physical effects in older adults. However, limited studies have assessed this relationship in Korea. Therefore, in this pilot study of densely populated urban dwellers, we aimed to investigate whether temporary but repeated experiences of the natural environment could positively change metabolism-related blood indicators. Methods: This study used pre- and post-interventional designs to investigate the effects of 16 weeks of gardening on lipid profiles in an urban adult population and investigate their relationships. This study was conducted 30 times at the H Botanical Garden in Yongin City from August 16, 2021 to November 30, 2021 (16 weeks, twice a week, 3 hours each time). Before and after the gardening program, a clinical pathologist collected blood samples from the participants. Results: High-density lipoprotein levels increased, low-density lipoprotein levels decreased, and total cholesterol levels decreased after the gardening activity. Conclusions: Our findings suggest that gardening has potential for clinical application as it has good control over the lipid profile through physical activity. These findings can be used as basic data for studying the relationship between urban populations and their living environment and for various studies in the future as experiencing the natural environment provides many health benefits.

• Advances in concrete construction
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• 제14권3호
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• pp.215-225
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• 2022

Thermal comfort and energy conservation are critical issues in the building sector. Energy consumption in the building sector should be reduced whilst enhancing the thermal comfort of occupants. Concrete is the most widely used construction material in buildings. Its thermal conductivity (k-value) has a direct effect on thermal comfort perception. This study aims to find the optimum value of replacing the normal aggregate with lightweight expanded clay aggregate (LECA) under high strengths and low thermal conductivity, density and water absorption. The k-value of the LECA concrete and its physical and mechanical properties have varying correlations. Results indicate that the oven-dry density, compressive strength, splitting tensile strength and k-value of concrete decrease when normal coarse aggregates are replaced with LECA. However, water absorption (initial and final) increases. Thermal conductivity and the physical and mechanical properties have a strong correlation. The statistical optimisation of the experimental data shows that the 39% replacement of normal coarse aggregate by LECA is the optimum value for maximising the compressive and splitting tensile strengths whilst maintaining the k-value, density and water absorption at a minimum.

• Elastomers and Composites
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• 제36권1호
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• pp.52-60
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• 2001

발포체의 물성은 발포체의 밀도, 사용된 폴리머의 기계적 물성과 열린 셀(open cell) 함량, 셀 크기, 셀 크기 분포, 셀 형태, 격벽의 두께 등을 포함하는 셀 구조에 의존하며 이러한 발포체의 밀도는 사용된 폴리머의 종류와 가교제의 농도, 발포제의 농도 그리고 가공 기술 및가공 조건 같은 다양한 원료물질과 가교조건에 영향을 받는다. Ethylene vinyl acetate coplymer (EVA) 발포체는 가교 발포체로서 가교속도와 발포제의 분해속도에 의해 발포특성에 영향을 받으며 이에 따라 발포체 물성에도 영향을 미친다. 본 연구에서는 가공 온도인 $155^{\circ}C$에서의 시간에 따른 발포제의 분해 속도 차이와 이에 따른 발포특성과 발포체의 물성에 대한 영향을 평가하였다. 발포제 분해 속도가 보다 느린 경우, 발포제 분해속도가 빠른 경우와 비교하여 낮은 밀도를 보여주었으며, 우수한 충격흡수성을 나타내었고 발포체의 셀 크기는 보다 균일하였다.

• 한국조경학회지
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• 제42권6호
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• pp.50-59
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• 2014

이 연구는 식생모듈박스에 적용한 레플렉숨을 중심으로 식물 생육특성 간의 관계 및 식물의 생육특성과 토양 물리적 특성의 관계를 파악하기 위하여 수행하였다. 이 실험에서 토양 물리적 특성과 식물 생육특성의 관계에 관한 연구의 분석은 SPSS Ver 19.0 for Window용 통계프로그램을 이용하여, 상관분석과 다중회귀분석을 실시하였다. 토양 물리적 특성과 생육특성의 다중회귀 분석 결과, 레플렉숨에 대한 회귀식은 초장=$3.993-14.070^*$(용적밀도)+$.233^*$(고상)+$.038^*$(액상)+$.068^*$(침투율)로 나타났으며, 이 중 용적밀도와 고상이 유의성 있게 나타났다. 레플렉숨에 대한 회귀식은 초폭=$2.931-33.925^*$(용적밀도)+$.566^*$(고상)+$.206^*$(액상)+$.027^*$(침투율)이며, 이 중 용적밀도와 고상이 유의성 있게 나타났다. 즉, 초장 및초폭과 토양의 물리적 특성은 일정한 회귀식으로 작성할 수 있다. 상하부 생체량과 건중량은 토양의 물리적 특성과 직접적인 상관성이 없는 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제51권6호
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• pp.542-554
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• 2023

This study is a continuation of our previous work, which focused on the resistance of jabon wood to termites after impregnation with wood vinegar (WV) and animal-based adhesive (kak). This paper presents the physicomechanical properties of fast-growing jabon wood impregnated with kak at two concentrations (8% and 10%) in wood vinegar or water as a solvent with and without 4% borax. The physical properties of the impregnation solution, that is, viscosity, density, pH, and solid content, were evaluated according to SNI 06-4567-1998. Some physical parameters, such as weight percent gain (WPG), density, water uptake, anti-swelling efficiency (ASE), crystallinity, and mechanical properties, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength parallel to the grain (CS), of the impregnated wood were determined. Based on these results, wood impregnated using a mixture of kak in WV presented better physical (increased WPG, density, dimensional stability, and crystallinity) and mechanical (increased MOE/MOR and compression strength) properties than wood impregnated with a water solvent or untreated wood. The wood impregnated using WV and water solvent improved the physical and mechanical properties. The density of the wood increased by 44%-58% and 32%-47%, ASE radial-tangential increased by 38%-45%; 15%-28% after 24 h of water immersion, crystallinity increased by 59%-74%; 36%, MOE increased by 46%-57%; 28%-31%, MOR increased by 29%-34%; 14%-27%, and compression strength increased by 40%-76%; 38%-72% values to untreated wood.

• Journal of Biosystems Engineering
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• 제33권2호
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• pp.101-105
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• 2008

Some physical properties of rapeseed such as geometric properties (linear dimensions, sphericity, seed volume, surface area) and gravimetric properties (the mass of one thousand seeds, bulk density) were analyzed at five levels of moisture content of 10.03, 14.91, 20.07, 25.06 and 30.12% (w.b.). The physical properties of rapeseed were evaluated as a function of seed moisture content. In the moisture range, when the moisture content increase, sphericity decreased from 0.946 to 0.927, and geometric mean diameter, seed volume and surface area increased from 2.17 to 2.31 mm, 5.58 to $6.88 \;mm^3$ and 14.76 to $16.77\;mm^2$ respectively. Mass of one thousand seeds increased from 5.04 to 6.46 g. Bulk density decreased from 579.3 to $549.2\;kg/m^3$ due to swelling of the seed.

• 대한임상전기생리학회지
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• 제7권1호
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• pp.11-15
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• 2009

Purpose : This study aims to comparison of ultrasonography on both sides of biceps brachii muscle of hemiplegic patient. Methods : The biceps brachii muscle of fifteen subjects (5 male, 10 female) with stroke were scanned with ultrasonography at the muscle belly at rest at elbow angles of 90 deg. The echogenicity (density, white area index; WAI, anatomic cross-sectional area; ACSA, volume) of ultrasonography was examined. Results : In the biceps brachii muscle, there were significant differences of density, WAI, ACSA, and volume between affected side and non-affected side. biceps brachii muscle, echogenicity (density, WAI) of the affected side was higher than non-affected side. biceps brachii muscle, echogenicity (ACSA, volume) of the non-affected side was higher than affected side. Conclusion : This study showed that change of skeletal muscle architecture properties occurred biceps brachii muscle of the affected side muscle of hemiplegic patient.

• The Journal of Korean Physical Therapy
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• 제9권1호
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• pp.71-79
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• 1997

The purpose of this study were to determined the effect of laser irradiation on the fibroblast activity. Cultures of 3T3 fibroblasts were subjected to Helium Neon laser(632.8 nm) irradiation of various energy density. On one, two and three consecutive days the fibroblast monolayers wert irradiated for period from 0 to 32 minutes with 8 mW of average output power. The fibroblast activity was determined by the quantitative assay of MTT, SRB and NR after incubation of the fibroblasts for 24 hours. Results show that exposure duration from 2 min to 32 min could increase MTT at three consecutive days, whereas control and 1 min, one and two days irradiation had were not inclosed. The SRB and NR were inclosed at two and three consecutive days from 2 min to 32 min, whereas control and 1 min, and once radiation were not increased. These result demonstrate that energy density from 0.48 to 7.64 J/cm could increase cellular protein contents and fibroblast activity at more than twice irradiation of laser, whereas low energy density (less than 0.24 J/m) and once irradiation of laser had no effect. The results suggest that the beneficial effect of the He-Ne laser with adequate dose on fibroblast activity in vitro.

• 펄프종이기술
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• 제46권6호
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• pp.26-33
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• 2014

Frankincense resin was applied to Hanji to improve its physical properties. The resin-treated paper showed the increasement of physical properties such as weight, thickness, and density. The highest increasement in weight and density of resin-treated paper were found at 30% treatment concentrations and the largest values of density were $41g/m^2$ Hanji. With the increasement of concentration, the brightness was decreased and transparency was improved. Of the mechanical properties of the paper, the tensile index and burst index showed the improved values. The tear index, however, was decreased. The frankincense resin showed the highest result in the tensile index of resin-treated paper and the basis weight of $41g/m^2$ Hanji. The air resistance of the resin-treated paper got improved with the increase of the concentration and $105g/m^2$ Hanji showed the highest values. The highest improvement in air resistance may make the resin-treated Hanji possible to use for semipermeable materials.

• Elastomers and Composites
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• 제58권4호
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• pp.208-215
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• 2023

In this study, the properties of polyurethane-polydimethylsiloxane (PU-PDMS) hybrid foams containing different types and contents of physical blowing agents (PBAs) were investigated. Two types of blowing agents, namely physical blowing agents and thermally expandable microspheres (TEM), were applied. The apparent density was measured using precisely cut foam samples, and the pore size was measured using image software. In addition, the microstructure of the foam was confirmed via scanning electron microscopy and transmission electron microscopy. The thermal conductivities related to the microstructures of the different foams were compared. When 0.5 phr of the hydrocarbon-based PBA was added, the apparent density and pore size of the foam were minimal; however, the pore size was larger than that of neat foam. In contrast, the addition of 3 phr of TEM effectively reduced both the apparent density and pore size of the PBAs. The increase in resin viscosity owing to TEM could enhance bubble production stability, leading to the formation of more uniform and smaller pores. These results indicate that TEM is a highly efficient PBA that can be employed to decrease the weight and pore size of PU-PDMS hybrid foams.