• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.1-6
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• 2015

We investigate the propagation characteristics of a pulse laser in a time-of-flight laser range finder (TOF-LRF) system with variations in atmospheric conditions, such as temperature, pressure, relative humidity, and the concentration of $CO_2$. The measurement error of distance related with the group velocity change in the TOF-LRF system is analyzed by considering the refractive index of the standard atmosphere with variations in atmospheric conditions. The dependence of the pulse width broadening induced by chromatic dispersion of the standard atmosphere on the operating wavelength and the initial pulse width of the light sources is discussed. The transmission of air with variations in the relative humidity or the concentration of $CO_2$ is analyzed by using different values of absorption coefficients depending on the operation wavelength of the light source in the TOF-LRF system.

• The Research Journal of the Costume Culture
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• v.24 no.6
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• pp.817-824
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• 2016

The introduction of natural dyes into modern dye houses is very promising green chemistry concept that should be popularized more to reduce the dependency of leather dyeing on some toxic and non-biodegradable synthetic dyes. In this study, the properties of dyeing of cochineal on cow leather were evaluated. The proper dyeing conditions were identified with dye uptake (K/S values) depending on the colorant concentration, dyeing duration, dyeing temperature, and dye bath pH. For the proper mordanting conditions, color changes for different mordants were observed as $La^{*}b^{*}$ and H V/C values. Color fastness (light, rubbing, and dry cleaning) was also examined. Additionally, antibacterial properties and UV protection were examined. The results were as follows: The optimized dyeing conditions were 300% o.w.f., $40^{\circ}C$, 40 min., and pH 5. The cow leather color was red in the absence of mordanting, while it was red purple after being mordanted with Al and Cu, and purple mordanted with Fe. The K/S value of cow leathers increased in the order of the dyeing using $AlK(SO_4)_2$ > $CuSO_4$ > $FeSO_4$. The colorfastness to light and rubbing were reduced compared to original (untreated) cow leather. However dry cleaning fastness was very satisfactory, with a 4~5 rating. The dyed and pre-mordanting dyed cow leather showed excellent antibacterial properties.

• Journal of Ecology and Environment
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• v.34 no.4
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• pp.347-355
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• 2011

Effects of forest thinning on community level properties have not been understood yet in Korea. We investigated regeneration patterns and trajectories after a disturbance by applying a chronosequence approach. Light availability, litter and woody debris cover, and species composition were determined for twenty 50 m line-transect samples representing a disturbance duration gradient (within 11 years). Environmental factors such as light availability and coverage of woody debris and litter changed abruptly after thinning and then returned to the pre-disturbance state. Although species richness was gained at shrub and ground layer in a limited way in both forests, cover of various functional types revealed diversity in their responses. Notably, Alnus firma stands exhibited a larger increment of cover in woody plants. Ordination analysis revealed different regeneration trajectories between natural and planted stands. Based on ordination analysis, rehabilitated stands showed movement to alternative states compared with natural ones, reflecting lower resilience to perturbation (i.e., lower stability). Our results suggest that community resilience to artificial thinning depends on properties of the dominant species. But to get more explanatory ecological information, longer-term static observations are required.

• Korean Institute of Interior Design Journal
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• v.16 no.5
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• pp.47-54
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• 2007

The change of modern society arouse the issue of the family structure and the demand of upbringing. According to the issue, the need of the upbringing is the big interest in society. This study is on the demand of the parents of students in eco-environmental space in child care center. The purpose of the study makes the suggestion the need of the eco-environmental space in child care center. The study progressed with looking up and giving questionaires in six child care centers which have eco-environmental space in Seoul. 210 questionaires were given out to parents and taken away 180 questionaires. The result of the study, parents required strongly to have the eco-environmental space in child care center. The natural interior materials, nature experimental outdoor ground and exterior garden were preferred overriding. The use of the woods and stones and eco-environmental adhesives are required as the natural Interior materials. And the natural light source can be imported in sky light, side window and atrium. Upcoming study would be directed in child care center without eco-environmental spaces. The next suggestion would be made in the needs of the eco-environmental space in child care center.

• Textile Coloration and Finishing
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• v.22 no.3
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• pp.207-213
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• 2010

Natural dyeing of Sangju silk for graveclothes with mulberry extract solution was studied. The anthocyanidin dye in the extracted mulberry solution was markedly influenced by pH condition, which resulted in the changed maximum light absorption from a $\lambda$max of 525nm in acidic condition to 380nm in alkaline condition possibly due to the irreversible transformation of anthocyanidin to cyanidin form of the dye. The color fastness properties to both light and washing were good when the fabrics were dyed at $80^{\circ}C$ with the mulberry-extracted solution upto twice extraction.

• Journal of Photoscience
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• v.5 no.2
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• pp.53-61
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• 1998

Using a squash plant, a chilling-sensitive species, and a spinach plant, a chilling-resistant one, effects of chilling temperature on the photosynthetic machinery were studied in terms of chlorophyll fluorescence. When thylakoid membranes were isolated and subjected to incubation at different temperatures, spinach showed stable photosystem II activity at the low temperature side, in contrast to squash which showed quite severe inactivation at low temperature. When parameters of chlorophyll fluorescence were examined, chilling in darkness did not affect either Fv/Fm or photochemical and non-photochemical quenching, in both types of plants. However, chilling of squash plants under irradiance of medium intensity caused a specific decrease in Fv/Fm accompanied by a decline in energy-dependent quenching. Contrastingly, photosystem li of spinach plants were not much affected by light-chilling. When the pool size of zeaxanthin was examined after exposure to high light at different temperatures, squash plants was shown to have a much lower content of antheraxanthin + zeaxanthin, as compared to spinach plants, during low-temperature photoinhibition. These results suggest that chilling-sensitive plants have low capacity to dissipate excitation energy nonradiatively, when they are exposed to low-temperature photoinhibition, and, as a consequence, more vulnerable to photoinhibitory, damage to the photosynthetic apparatus.

• Fashion & Textile Research Journal
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• v.10 no.3
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• pp.377-384
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• 2008

For the purpose of standardization and practicability of natural dyeing, the mordanting and dyeing properties of gallnut was studied. In this study, the colorants of gallnut were extracted with boiling water. Chitosan crosslinked cotton fabrics were been dyed with aqueous extract of gallnut and their dyeabilities on the fabrics were studied. Additionally, the fastness to washing and light were also investigated. Cotton fabrics were treated with a crosslinking agent epichlorohydrin in the presence of chitosan to provide the cotton fabrics the dyeing properties of natural dye(gallnut) by the chemical linking of chitosan to the cellulose structure. The chitosan finishing and durable press finishing of the cotton fabrics carried out simultaneously in the mercerization bath. The dyeability(K/S), which was obtained by CCM observation, remarkably increased as the concentration of chitosan was high. Dye ability of gallnut showed higher toward chitosan treated cotton than controlled cotton fabric under condition at $60^{\circ}C$, for 20 min. The hue value indicated reddish yellow with increasing the crosslinked chitosan concentration. And the color fastness to washing and light was the almost the same.

• Steel and Composite Structures
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• v.31 no.5
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• pp.529-539
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• 2019

Current paper deals with thermoelastic static and free vibrational behaviors of axisymmetric thick cylinders reinforced with functionally graded (FG) randomly oriented graphene subjected to internal pressure and thermal gradient loads. The heat transfer and mechanical analyses of randomly oriented graphene-reinforced nanocomposite (GRNC) cylinders are facilitated by developing a weak form mesh-free method based on moving least squares (MLS) shape functions. Furthermore, in order to estimate the material properties of GRNC with temperature dependent components, a modified Halpin-Tsai model incorporated with two efficiency parameters is utilized. It is assumed that the distributions of graphene nano-sheets are uniform and FG along the radial direction of nanocomposite cylinders. By comparing with the exact result, the accuracy of the developed method is verified. Also, the convergence of the method is successfully confirmed. Then we investigated the effects of graphene distribution and volume fraction as well as thermo-mechanical boundary conditions on the temperature distribution, static response and natural frequency of the considered FG-GRNC thick cylinders. The results disclosed that graphene distribution has significant effects on the temperature and hoop stress distributions of FG-GRNC cylinders. However, the volume fraction of graphene has stronger effect on the natural frequencies of the considered thick cylinders than its distribution.

• International Journal of High-Rise Buildings
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• v.12 no.2
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• pp.107-120
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• 2023

Tall buildings are frequently decried as unsustainable due to their excessive energy usage. Early skyscrapers used natural light and ventilation to facilitate human comfort and applied organic materials such as stone, glass, wood, concrete, and terra cotta for cladding and finishes. With the advent of fluorescent lighting, modern heating, ventilation, air-conditioning (HVAC) systems, and thermally sealed curtain walls, tall office buildings no longer had to rely on natural light and ventilation to provide comfort. Energy efficiency was not a significant factor when the operational costs of buildings were relatively inexpensive. However, today's skyscrapers must become more energy-efficient and sustainable due to energy crises and climate change. This paper highlights vital energy-efficient design principles and demonstrates with illustrative case studies how they are applied to tall buildings in various parts of the world. It shows how sustainable environmental systems do not act alone but are integrated with advanced curtain wall systems, sky gardens, and atria, among others, to regulate and sustain thermal comfort and conserve energy.

• Journal of Fashion Business
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• v.9 no.3
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• pp.99-113
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• 2005

Recently, problems related to the natural dyeing have been addressed. Severer problems have been posed by the elution at metallic ions and dyestuff tram dyed fabrics. In order to prevent the elution tram the dyed fabrics, it is needed to improve the fastness. Especially, it is the most important measure to improve the fastness to perspiration in terms at human body safety. In this study, we employed chitosan pretreatment method bet ore the dyeing process, anticipating that the pretreatment might improve the fastness. We used Al, Sn, and Cu as mordants and investigated the fastness to light and perspiration of the chitosan treated and dyed fabric specimens. By the chitosan pretreatment, the fastness to perspiration improved, while the fastness to light did not.