• 농업과학연구
• /
• 제40권3호
• /
• pp.203-208
• /
• 2013

Differences in the filling amount of substrates in container can influence severely on the soil physical properties and crop growth. This research was conducted to secure the fundamental informations related to the changes in soil physical properties as influenced by the filling amount of coir dust-based substrates in container. For the experiment, three substrates were formulated by blending coir dust (CD) with expanded rice hull (CD+ERH, 8:2, v/v), carbonized rice hull (CD+CRH, 6:4, v/v) or ground and aged pine bark (CD+GAPB, 8:2, v/v). Based on the optimum bulk density, the amount of substrates filled in 347.5mL aluminum cylinder were adjusted to 90, 100, 110, 120, and 130%. Then the changes in total porosity (TP), container capacity (CC), and air-filled porosity (AFP) by various filling amounts were measured. The TP decreased linearly in CD+ERH and CD+GAPB and quadratically in CD+CRH as the filling amounts of the media increased from 90% to 130%. The CC in CD+ERH and CD+GAPB media increased as the filling amount increased from 90% to 120%, then decreased in 130%, showing quadratic change. The CC in CD+CRH was the highest in 90% filling amount and decreased gradually as the filling amount of root medea increased. The AFPs in CD+ERH and CD+GAPB media were 38 and 37%, respectively in 90% filling amount and they decreased drastically until 110% filling, then gradually in 120 and 130% filling amount showing the quadratic changes. The AFP of CD+CRH at 90% filling amount was 22% and it decreased as the filling amount increased until 130%, showing linear change. These results indicate that the increase in filling amount of substrates influenced more severely the AFP than CC, and careful consideration on container filling is required to provide a better root condition thus maximize crop growth.

• Restorative Dentistry and Endodontics
• /
• 제46권1호
• /
• pp.2.1-2.8
• /
• 2021

Objectives: New premixed bioceramic root repair materials require moisture for setting. Using micro-computed tomography (micro-CT), this study evaluated the filling ability and volumetric changes of calcium silicate-based repair materials (mineral trioxide aggregate repair high-plasticity [MTA HP] and Bio-C Repair, Angelus), in comparison with a zinc oxide and eugenol-based material (intermediate restorative material [IRM]; Dentsply DeTrey). Materials and Methods: Gypsum models with cavities 3 mm deep and 1 mm in diameter were manufactured and scanned using micro-CT (SkyScan 1272. Bruker). The cavities were filled with the cements and scanned again to evaluate their filling capacity. Another scan was performed after immersing the samples in distilled water for 7 days to assess the volumetric changes of the cements. The statistical significance of differences in the data was evaluated using analysis of variance and the Tukey test with a 5% significance level. Results: Bio-C Repair had a greater filling ability than MTA HP (p < 0.05). IRM was similar to Bio-C and MTA HP (p > 0.05). MTA HP presented the largest volumetric change (p < 0.05), showing more volume loss than Bio-C and IRM, which were similar (p > 0.05). Conclusions: Bio-C Repair is a new endodontic material with excellent filling capacity and low volumetric change. The gypsum model proposed for evaluating filling ability and volumetric changes by micro-CT had appropriate and reproducible results. This model may enhance the physicochemical evaluation of premixed bioceramic materials, which need moisture for setting.

• 펄프종이기술
• /
• 제45권1호
• /
• pp.52-58
• /
• 2013

The effets of the pretreatments of tropical kapok fibers were evaluated in this study in terms of water sorption capacity and oil sorption capacity. The alkali treatments with NaOH resulted in the reduction of lignin, oil and hemicellulose, which were detected with FT-IR spectrum. The reduction of the lyphophilic components such as fat on kapok fiber by the ozone treatments were also measured with FT-IR spectrum. The oil sorption capacity of kapok fiber was decreased by the alkali treatments and the ozone treatments, while the water sorption capacity was increased. The liquid sorption capacity were greatly affected by the mechanical cutting of kapok fiber which exposed the big lumen of kapok fiber. The hydrophilic property of kapok fiber could be controlled by the pretreatments, which would increase the applicability of kapok fiber for preparation of various functional paper products.

• 기술혁신연구
• /
• 제31권2호
• /
• pp.303-332
• /
• 2023

본 연구는 '국가 경제에 큰 영향을 미치는 중소기업들의 경쟁우위 강화와 성과 창출을 위해 어떠한 무형자원이 중요할까? 특히, 시장 환경 변화가 크고, 위기·재난 상황일 경우에는 어떤 역량이 필요할까? 시장 환경 변화가 클 때, 중소기업 중 플랫폼기업과 일반 기업의 기업성과에 미치는 역량은 다를 수 있지 않을까?'라는 질문에서 시작되었다. 이를 위해 중소기업의 경쟁우위와 성과에 영향을 미치는 주요 역량으로 기업가지향성, 흡수역량, 조직회복탄력성을 제시하였고, 특히, 최근 기업의 핵심역량으로 부상하고 있는 조직회복탄력성이 기업성과에 어떠한 조절효과를 갖는지 실증하였다. 또한, 플랫폼기업과 일반기업을 비교하여 기업성과에 미치는 조직회복탄력성의 조절효과를 분석하였으며, 조직회복탄력성의 어떤 하위요소에 따라 조절효과가 달라지는지 실증하였다. 연구 결과, 기업가지향성, 흡수역량은 모두 기업성과에 유의한 정(+)의 영향을 미치며, 조직회복탄력성도 기업성과에 유의한 정(+)의 영향을 미치는 것으로 나타났다. 또한, 조직회복탄력성의 하위 구성요소인 위기준비 역량, 위기대응 역량, 변화주도 역량은 기업가지향성과 기업성과 간 관계를 유의하게 조절하고, 위기준비 역량과 변화주도 역량은 흡수역량과 기업성과 간 관계를 유의하게 조절하였다. 그리고, 기업가지향성과 기업성과 간 관계에서 위기준비 역량의 조절효과, 기업가지향성과 기업성과 간 관계에서 위기대응 역량의 조절효과는 플랫폼기업에서만 유의한 결과를 보였다. 연구 결과는 조직회복탄력성이 기업성과에 직접 영향을 줄 뿐 아니라, 기업가지향성, 흡수 역량과 상호작용하여 기업성과를 더욱 높여줄 수 있으며, 플랫폼기업과 일반기업 간 조직회복 탄력성의 조절효과가 다를 수 있음을 시사하였다. 이러한 결과는 중소기업의 경영에 실질적인 도움이 될 것으로 기대된다.

• Journal of Nutrition and Health
• /
• 제36권3호
• /
• pp.287-297
• /
• 2003

This intervention study was performed to assess the effect of spirulina on lipid metabolism, antioxidant capacity, and immune function in elderly Koreans. The subjects were 6 male and 6 female people between the ages of 60 and 75, who were given spirulina supplements of 7.5 g/day for 24 weeks. Dietary intake, anthropometric measurements and biochemical assessment for plasma lipid levels, antioxidant status and immune function were measured before and throughout the intervention period. Before entering the study, the subjects were in relatively good health. Their nutrient intake was satisfactory, and anthropometric indices and plasma nutrient levels were within the normal range. Spirulina supplementation for 24 weeks did not affect dietary intake and anthropometric parameters. However, considerable changes were observed in blood lipid profiles, antioxidant capacity, and immune indices. The plasma concentrations of triglycerides, total- and LDL-cholesterol decreased from 4 weeks of the supplementation period. The antioxidant capacity improved, as shown in increasing TAS and decreasing TBARS after supplementation. Improved immune function was also observed as the PBL lymphocyte proliferation rate and plasma C3 levels increased. The above effects of spirulina supplementation did not differ between mild hypercholesterolemic (cholesterol $\geq$ 200mg/d1) and normochole-sterolemic (cholesterol < 200 mg/dl) subjects. This study provided evidence that spirulina could be used as dietary supplementation in nutritionally vulnerable groups to improve nutritional and health status and to prevent chronic disease such as hyperlipidemia or oxidation-prone diseases. further studies in this area with various population groups are warranted.

• Journal of Ginseng Research
• /
• 제33권1호
• /
• pp.40-47
• /
• 2009

This study evaluates changes in the chemical composition and bioactivities of American ginseng (Panax quinquefolius L.) processed by boiling in water, $75^{\circ}C$ for 10, 20, 30, and 40 min, and autoclaving at high temperatures, $115^{\circ}C$ for 30 and 60 min and $130^{\circ}C$ for 90 and 120 min. Total ginsenoside contents of boiled ginseng remained relatively unchanged, whereas the contents of autoclaved ginseng samples significantly decreased with an increase of both time and temperature. Compared to unheated ginseng (control), the color of both boiled and autoclaved ginseng decreased in lightness and increased in redness. The acidic polysaccharide contents, the total phenolic contents and the antioxidant capacity of boiled and autoclaved ginseng were higher than the untreated ginseng, with the highest values being exhibited by the autoclaved samples. In particular, the antioxidant capacity of unheated ginseng increased about 2.5 times ($285.7{\pm}14.03\;mg$/100g to $777.2{\pm}26.4\;mg$/100g) when ginseng was autoclaved at $130^{\circ}C$ for 120 min as compared to the control. It was concluded that as American ginseng was processed at a high temperature, especially steam-heated in an autoclave, its chemical constituents changed and, in particular, acidic polysaccharides, total phenolics and antioxidant capacity were considerably increased.

• 한국전기전자재료학회논문지
• /
• 제19권1호
• /
• pp.100-106
• /
• 2006

Today, restricted energy sources, environmental considerations and the high cost of transporting fuel have limited the number and location of available power plant sites. The pressures resulting from these conditions have tended to require the construction of long, high-capacity, high-voltage power lines. it's used to adapt to STACIR/AW(Super Thermal-resistant Aluminum alloy Conductors, aluminum-clad Invar-Reinforced) conductor for coping with these situations. STACIR/AW conductor was formed by the combination of INVAR/AW as the core for low sag and super thermal-resistant aluminum alloy conductor for current capacity increase. increase of temperature by current capacity and long span lines make the susceptible to the deterioration of thermo-mechanical properties(conductivity, tensile strength, E-modulus and twist property et al). In the present work, changes of thermo-mechanical properties with aging have been studied in STACIR/AW $410 mm^2$ conductor with forms of single wire and strand wire.

• Industrial Engineering and Management Systems
• /
• 제12권3호
• /
• pp.207-223
• /
• 2013

Revenue management (RM) has been widely used to model products characterized as perishable. Classical RM model assumed that price is the sole factor in the model. Thus price adjustment becomes a crucial and costly factor in business. In this paper, an optimal pricing model is developed based on minimization of soft customer cost, one kind of price adjustment cost and is solved by Lagrange multiplier method. It is formed by expected discounted revenue/bid price integrating quantity-based RM and pricing-based RM. Quantity-based RM consists of two capacity models, namely, booking limit and overbooking. Booking limit, built by assuming uncertain customer arrival, decides the optimal capacity allocation for two market segments. Overbooking determines the level of accepted order exceeding capacity to anticipate probability of cancellation. Furthermore, pricing-based RM models occupancy/demand rate influenced by internal and competitor price changes. In this paper, a mathematical model based on game theoretic approach is developed for two conditions of deterministic and stochastic demand. Based on the equilibrium point, the best strategy for both hotels can be determined.

• 설비공학논문집
• /
• 제17권9호
• /
• pp.824-829
• /
• 2005

MHR(Metal Hydride Refrigerator) powered by MGT exhaust gas is investigated to find out the optimum conditions corresponding to MGT operating powers. There are many factors to affect cooling capacity of MHR. In this study, the effect of switching time, flow rate of brine on cooling temperature and capacity is investigated. The present results show (1) hydrogen reaction is saturated with 25 min switching time at 25 kW MGT power, (2) cooling power shows maximum phenomenon with increasing switching time, (3) optimum switching times are 20 minutes for 15kW MGT power and 15 minutes for 20, 25kW MGT power, (4) according to increasing brine flow rate, cooling capacity shows decrease at 15 kW MGT power and changes little at above 20 kW MGT power.

• PNF and Movement
• /
• 제16권3호
• /
• pp.389-395
• /
• 2018

Purpose: The purpose of this study was to investigate whether the respiratory function of patients with stroke was different on the ground and under water. Methods: We recruited 14 adults who had experienced a stroke (12 male, 2 female) for our study. We measured forced vital capacity, forced expiratory volume at one second, maximum inspiratory pressure, and maximum expiratory pressure when the participants breathed on the ground and under water. On the ground, the participants were safely supported using a table and chair and were measured in a standing posture. For measuring under water, the participants were immersed in water in a standing position to clavicle height. The participants were measured while standing, and the assistant supported them when they needed help. The collected data were analyzed by a paired t-test. Results: Forced vital capacity and forced expiratory volume at one second were significantly lower in water than on the ground when breathing at maximum. Maximum inspiratory pressure was not significantly different when standing on the ground or in water, but maximum expiratory pressure was significantly higher in water than on the ground. Conclusion: It has been confirmed that the hydrostatic pressure affecting stroke patients immersed in water affects the forced expiratory volume at one second while reducing the forced vital capacity and increasing the maximum expiratory pressure.