• Corrosion Science and Technology
• /
• v.23 no.4
• /
• pp.334-342
• /
• 2024

The need for efficient and sustainable energy storage solutions has emerged due to a rapidly increasing energy demand and growing concerns about environmental issues. Among various energy storage methods, lithium secondary batteries are widely used in a variety of electronic devices such as smartphones, laptops, electric vehicles, and large-scale power storage systems due to their high energy density, long lifespan, and cost competitiveness. Recently, all-solid-state batteries (ASSBs) have attracted great attention because they can reduce the risk of fire associated with liquid electrolytes. Additionally, using high-capacity alternative anodes and cathodes in ASSBs can enhance energy density. However, ASSBs that use solid electrolytes experience a degradation in their electrochemical performances due to resistance at solid-solid interfaces. These interfaces can also result in poor physical contact and the presence of products formed from chemical and electrochemical reactions. Solving this interface problem is a critical issue for the commercialization of ASSBs. This review summarizes interfacial reactions between the cathode and solid electrolyte, along with research aimed at improving these interactions. Future development directions in this field are also discussed.

• Journal of the Korean Wood Science and Technology
• /
• v.52 no.5
• /
• pp.450-458
• /
• 2024

Litsea elliptica, a Southeast Asian tree with a rich history of medicinal applications, is attracting increasing research attention. This study investigated the effects of leaf maturity and solvent selection on the extraction of bioactive compounds from L. elliptica leaves, specifically with regard to their antioxidant activity. 2,2'-Azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) method was employed to quantify the free radical scavenging capacity of L. elliptica leaf extracts prepared using three different solvents (n-hexane, ethyl acetate, and ethanol) at three different leaf stages (tender, immature, and mature). These results highlight the significant effects of leaf maturity and solvent selection on the extraction of phenolic compounds and flavonoids from L. elliptica leaves. Ethanol is the most effective solvent for the extraction of bioactive compounds, particularly from mature leaves. The ethanol extraction of tender leaves demonstrated potential for optimizing the antioxidant content. Further research is necessary to investigate the specific factors influencing the observed differences in antioxidant activity between leaves of varying ages and the potential impacts of other bioactive compounds present in the leaves.

• Steel and Composite Structures
• /
• v.52 no.4
• /
• pp.451-460
• /
• 2024

Hollow reinforced concrete columns confined with GFRP tubes (GRCH) are composite members composed of the outer GFRP tube, the PVC or other plastic tube as the inner tube, and the reinforced concrete between two tubes. Because of their high ductility, light weight, corrosion resistance and convenient construction, many researchers pay attention to the composite members. However, there are few studies on GRCH members under eccentric compression compared with those under axial compression. Eight hollow columns were tested under eccentric compression, including one axial compression column and seven eccentric compression columns. The failure modes and force mechanisms of GRCH members were analyzed, considering the varying in hollow ratio, reinforcement ratio and eccentricity. The test results showed that configuring steel bars can greatly increase the bearing capacity and ductility of the members. Each component (GFRP tube, concrete, steel bar) had good deformation coordination and the strength of each material could be fully utilized. But for specimens with larger eccentricity ratio (e_r=0.4) and larger hollow ratio (χ=0.55), the restraining effect of GFRP tube on concrete was significantly decreased.

• Journal of Periodontal and Implant Science
• /
• v.47 no.2
• /
• pp.77-85
• /
• 2017

Purpose: Guided bone regeneration (GBR) is the most widely used technique to regenerate and augment bones. Even though augmented bones (ABs) have been examined histologically in many studies, few studies have been conducted to examine the biological potential of these bones and the healing dynamics following their use. Moreover, whether the bone obtained from the GBR procedure possesses the same functions as the existing autogenous bone is uncertain. In particular, little attention has been paid to the regenerative ability of GBR bone. Therefore, the present study histologically evaluated the regenerative capacity of AB in the occlusive space of a rat guided bone augmentation (GBA) model. Methods: The calvaria of 30 rats were exposed, and plastic caps were placed on the right of the calvaria in 10 of the 30 rats. After a 12-week healing phase, critical-sized calvarial bone defects (diameter: 5.0 mm) were trephined into the dorsal parietal bone on the left of the calvaria. Bone particles were harvested from the AB or the cortical bone (CB) using a bone scraper and transplanted into the critical defects. Results: The newly generated bone at the defects' edge was evaluated using micro-computed tomography (micro-CT) and histological sections. In the micro-CT analysis, the radiopacity in both the augmented and the CB groups remained high throughout the observational period. In the histological analysis, the closure rate of the CB was significantly higher than in the AB group. The numbers of cells positive for runt-related transcription factor 2 (Runx2) and tartrate-resistant acid phosphatase (TRAP) in the AB group were larger than in the CB group. Conclusions: The regenerative capacity of AB in the occlusive space of the rat GBA model was confirmed. Within the limitations of this study, the regenerative ability of the AB particulate transplant was inferior to that of the CB particulate transplant.

• Parasites, Hosts and Diseases
• /
• v.38 no.2
• /
• pp.51-57
• /
• 2000

Follow-up studies have been conducted every three years on the endemicity of Gymnophalloides seoi infection in a small coastal village of Chollanam-do (Province), Korea, since it was first known as an endemic area in 1994. Special attention was given to its egg laying capacity in the human host. In fecal examinations, the overall helminth egg and/or cyst positive rate was 78.7% (74/94) in 1997 and 76.6% (82/107) in 2000. Among them G. seoi eggs showed the highest rate; 71.3% (67/94) in 1997 and 72.0% (77/107) in 2000. The average number of eggs per gram of feces (EPG) was 1,015 in 1997, while a reduced rate of 353 was observed in 2000. In 1997, total of 320,677 adult flukes of G. seoi (av. 10,344/person, 94-69,125 in range) were collected from the diarrheic stools of 31 treated patients. The EPG/worm obtained from 21 cases ranged from 0.04 to 0.77 (av. 0.23), suggesting density-dependent constraints on the worm fecundity. The relationship between the worm burden (X) and EPG/worm (Y) can be expressed as $Y=0.42{\cdot}e{\cdot}^{-l.2x}(r=0.49)$. The results showed that G. seoi infection is persistently endemic in this village.

• Environmental and Resource Economics Review
• /
• v.22 no.2
• /
• pp.367-391
• /
• 2013

After the Fukushima nuclear accident, the external costs of generating electricity from nuclear power plants such as additional safety compliance costs and possible accident risk action costs have gained increasing attention from the public, policy-makers and politicians. Consequently, estimates of the external costs of nuclear power are very deliberate issue that is at the center of the controversy in Korea. In this paper, we try to calculate the external costs associated with the safety of the nuclear power plants, particularly focusing on additional safety compliance costs and possible accident risk action costs. To estimate the possible accident risk action costs, we adopt the damages expectation approach that is very similar way from the external cost calculation of Japanese government after the Fukushima accident. In addition, to estimate additional safety compliance costs, we apply the levelized cost of generation method. Furthermore, we perform the sensitivity analysis to examine how much these social costs increase the electricity price rate. Estimation results of the additional security measure cost is 0.53Won/kWh ~ 0.80Won/kWh depending on the capacity factor, giving little change on the nuclear power generation cost. The estimates of possible accident risk action costs could be in the wide range depending on the different damages of the nuclear power accident, probability of the severe nuclear power accident and the capacity factor. The preliminary results show that it is 0.0025Won/kWh ~ 26.4188Won/kWh. After including those two external costs on the generation cost of a nuclear power plant, increasing rate of electricity price is 0.001%~10.0563% under the capacity factor from 70% to 90%. This paper tries to examine the external costs of nuclear power plants, so as to include it into the generation cost and the electricity price. This paper suggests one of the methodologies that we might internalize the nuclear power generations' external cost, including it into the internal generation cost.

• Journal of Technology Innovation
• /
• v.21 no.2
• /
• pp.57-84
• /
• 2013

New product development(NPD) is imperative management activity for growth and survival of the firm. In the context of the small and medium-sized enterprises(SMEs), the firm became further dependent upon NPD with the increasing turbulence in environments. This research suggests the role of entrepreneurship orientation(EO) and absorptive capacity(ACAP) that affect the success rate of NPD in SMEs. Although each of them has been highlighted as critical resources in the aspect of the sustainable competitive advantage, the relationship and the effect between EO and ACAP have received scant attention. Based on the sample of 261 Korean SMEs, this study examines the direct/indirect effect of EO and ACAP on NPD performance. While innovativeness of EO has the direct effect on NPD performance, both risk-taking and proactiveness of EO show no significance. While realized ACAP has the positive influence on NPD performance, potential ACAP shows no significant influence. In addition, we found that the impact of innovativeness on NPD performance was being partially mediated by ACAP whereas the relationship between proactiveness and NPD performance being fully mediated by ACAP. These findings would provide generic insights that both exploration and exploitation regarding knowledge and resources in SMEs are necessary in order to increase NPD performance and two activities have to align with EO.

• Journal of Hydrogen and New Energy
• /
• v.9 no.1
• /
• pp.16-24
• /
• 1998

Recently Zr-based $AB_2$ type hydrogen absorbing alloy has received much attention as a negative electrode material for the Ni-MH batteries because of its high capacity. In this study $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy was chosen and the effects of heat treatment and a partial substitution of the Mo in Mn site on the various electrode properties were investigated. The alloys was prepared by arc melting (as-cast sample). Some of them were heat treated at $1,100^{\circ}C$ for 4 hours. After this they were differentiated by the different cooling rates of slow cooling and quenching. Various electrode characteristics such as activation process, high rate dischargeability and self discharge characteristic were investigated with the three types of electrodes. It was found that heat treated alloys resulted in an increase in plateau flatness of P-C isotherms however both discharge capacity and high rate capability were decreased. And the partial substitution of Mo for Mn in $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy improved the self-discharge characteristic without the loss of discharge capacity (300mAh/g).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.434-442
• /
• 2019

Low Impact Development(LID) techniques has been attracting attention as a countermeasure to solve frequent flood damage in urban areas. LID is a techniques for returning to the natural hydrological cycle system by infiltrating the runoff from the impervious surface into the soil. The Bio-retention, one of the LID element technology has outflow reduction effect by reserving and infiltrating storm water runoff from watersheds. Recently, a number of studies have been carried out as interest in the reduction of storm water runoff and non-point pollutants in Bio-retention has increased. However, quantitative analysis on the outflow reduction of Bio-retention applied to small watershed is insufficient. In this study, Bio-retention model was constructed in a small watershed using K-LIDM which is capable of hydrologic analysis. When the storage capacity was increased or dividing the Bio-retention and watershed, the outflow reduction effect was 20% according to the storage capacity increase and 5~15% in the distributed Bio-retention system. The results of this analysis will be used as the basic data of future Bio-retention research related to watershed characteristics, vegetation type and soil condition.

• Journal of Life Science
• /
• v.30 no.12
• /
• pp.1033-1041
• /
• 2020

Many people of all ages wish to have lighter skin for cosmetic reasons, and natural products attract more attention than chemically synthesized compounds. Uncaria rhynchophylla is widely used in Asia as a traditional herbal medicine. In order to find novel skin whitening agents, the present study evaluated the antioxidant activity and potential tyrosinase-inhibiting properties of U. rhynchophylla. Specifically, this study analyzed the antioxidant capacity of a 70% ethanolic extract of U. rhynchophylla as well as its effects on tyrosinase activity and melanin synthesis. Total mRNA levels were examined using reverse transcription polymerase chain reaction. The results revealed that U. rhynchophylla extracts exhibit great antioxidant capacity and significant levels of polyphenol and flavonoid compounds. U. rhynchophylla extracts can also powerfully inhibit tyrosinase activity. This same capacity was observed in melanoma B16F10 cells; that is, U. rhynchophylla extracts suppressed intracellular tyrosinase activity and reduced the amount of melanin in treated cells. In addition, a 1 mg/ml concentration of U. rhynchophylla extract significantly reduced the mRNA expression levels of tyrosinase. U. rhynchophylla extracts decrease tyrosinase and inhibit melanogenesis in B16F10 cells. This finding suggests that U. rhynchophylla has great potential as a natural whitening agent in skincare products.