Silver nanomaterials have been intensively applied in consumer products of diverse industrial sectors because of their strong biocidal properties and reported to be hazardous to aquatic organisms once released in the environment. Nanomaterials including sliver, are known to be different in toxicity according to their physicochemical characteristics such as size, shape, length etc. However studies comparing toxicity among silver nanomaterials with different physicochemical characteristics are very limited. Here, toxicities of silver nanomaterials with different size (50, 100, 150 nm), length (10, 20 μm), shape (wire, sphere), and coating material (polyvinylpyrrolidone, citrate) using OECD test guidelines were evaluated in aquatic species (zebrafish, daphnia, algae) and compared. On a size property, the smaller of silver nanomaterials, the more toxic to tested organisms. Sphered type of silver nanomaterials was less toxic to organisms than wired type, and shorter nanowires were less toxic than longer ones. Meanwhile the toxic effects of materials coated on silver nanomaterials were slightly different in each tested species, but not statistically significant. To the best of our knowledge, it is first investigation to evaluate and compare ecotoxicity of silver nanomaterials having different physicochemical characteristics using same test species and test guidelines. This study can provide valuable information for human and environmental risk assessment of silver nanomaterials and guide material manufacturers to synthesize silver nanomaterials more safely to human and environment.

Pollutants removal and disinfection effect of secondary effluent from final settling tank of sewage treatment plant of W city were investigated in Loop Reactor using ordinary granular activated carbon(GAC) and GAC coated with silver nanoparticles. The results showed that the removal efficiency of CODMn, T-N and T-P using GAC with silver nanoparticles were higher than using the ordinary GAC. The removal efficiency of T-P using GAC with silver nanoparticles is 45.4% and that of T-P using ordinary GAC is 30.9% in the same case of the input amount of 20 g/L of GAC. The total califorms is reduced according to increasing input amount of GAC with silver nanoparticles and ordinary GAC. The disinfection efficiency of total coliforms in case of GAC with silver nanoparticles is much higher than that in case of ordinary GAC. For all experiments using the silver nanoparticles, the total coliforms is under 26 cfu/mL and this shows very excellent disinfection effect.

As social media platforms (e.g., Facebook) and related online communication channels (e.g., review websites and community forums) grow in quantity and commercial orientation, marketing practitioners and scholars alike have recognised the importance of understanding and influencing online consumer communication processes. Specifically, it is suggested that online opinion leaders (‘Epinion leaders’) can be utilised as a target group to manage negative e-word-of-mouth (‘e-WOM’) and e-complaints. This study identifies and targets Epinion leaders and explores three central personality characteristics – altruism, self-confidence and the need for uniqueness – as a means of understanding Epinion leaders’ motivations to communication and tailoring corporate communication campaigns. The study focusses herby on the rapidly growing and increasingly influential 50-years+ e-commerce segment (i.e., ‘silver surfers’). Based on an online survey of 1,700 e-consumers aged 50 years and older, the proposed structural equation model verifies the positive influence of Epinion leadership on the propensity to spread negative e-WOM and e-complaints while demonstrating the applicability of personality characteristics as means of influencing consumers’ online communication strategies. The findings demonstrate that addressing consumers’ self-confidence can be an essential way of reducing negative e-WOM and encouraging e-complaints, which show opposing effects on customer satisfaction. For practitioners, this study emphasises the usefulness of negative Epinion leaders as a target group and recommends fostering consumers’ self-confidence in order to prevent negative online opinion-cascades and increase overall satisfaction.

Facilitated olefin transport membrane, containing positively charged silver nanoparticles (AgNPs) as olefin carriers dispersed in poly(vinyl pyrrolidone) (PVP), leads extremely high separation performances for propylene/propane mixtures. In this study, as representatives of electron withdrawing nitrobenzene compounds, 1,2-dinitrobenzene (DNB) and 3,4-dinitro toluene (DNT) were used for PVP/AgNPs membranes. The correlation between the surface charge density of AgNPs and the separation performance was investigated with X-ray photoelectron spectroscopy (XPS). A fairly good linear correlation between the surface charge density and the separation performance was confirmed, which meant that the positive charge density on the surface of AgNPs may be a key factor in determining the separation performance of facilitated olefin transport membranes.

고분자막이 가진 수투과능 한계와 비가역적 막오염에 의한 효율 저하는 막기반 수처리공정의 추가적인 경쟁력 확보를 위해 해결해야 하는 문제이다. 본 연구에서는 초고속 물투과 특성과 뛰어난 선택성을 지닌 Graphene oxide (GO)막 에 뛰어난 항균성을 가진 은나노(nAg)가 코팅된 막을 제작, 평가하였다. GO막 은 막오염 저감에 효과적일 수 있는 높은 친수성과 음표면전하와 같은 특성과 막오염에 취약할 수 있는 높은 비표면적과 뛰어난 흡착능력과 같은 특성을 동 시에 가진다. 따라서, 논란의 부분이 있는 GO막의 막오염에 대한 저항성의 확실한 향상을 위해 nAg를 적용하였다.

The purpose of this study is to propose a specialized clothes-sizing system for elderly (aged 60~79) obese women satisfying the following conditions based on the data from the fifth Korean Agency for Technology and Standards (2004): a Rohrer's index of over 1.6, a BMI of over 25, and a WHR of over 0.85. The lower bodies of elderly obese women tends to be shorter and wider than average. Particularly, their torsos from the chest to the waist tend to be more obese than other areas. According to the KS standards, the clothes-sizing system sets up its size intervals as follows: 5cm in stature, 5cm and 3cm in bust, 3cm in waist, and 3cm in hip. Based on the dualistic distribution of each section, the names of the sections indicating high distribution are suggested. For suit tops, 11 sizes are selected as distributed in the 145-155cm stature section and 91-103cm bust section. For casual tops, nine sizes are selected as distributed in the 145-155cm stature section and 90-105cm bust section. For bottoms, 11 sizes are selected as distributed in the 82-97cm waist section and 91-97cm hip section. According to the KS standards, detailed sizes are suggested in the division of basic and reference areas.

고성능 투명 전극의 개발은 유기 태양 전지, 유기 발광 다이오드와 같은 저가형 유연 유기 광전자 소자의 개발에 매우 중요하다. 가장 널리 쓰이고 있는 투명전극인 indium tin oxide (ITO)는 비싼 가격과 잘 깨어지는 특성 을 가지고 있어서 저가형 유연 전자 소자의 개발에 많은 제한을 주고 있으며, 이를 극복하기 위한 대체 투명 전극의 개발에 대한 연구가 활발히 진행되고 있다. 은 나노와이어(silver nanowire, AgNW)는 우수한 전기 전도도와 광 투과 도를 가지고 저렴하며 뛰어난 유연성 때문에 ITO의 대체 투명전극으로서 큰 각광을 받고 있다. 그러나 AgNW의 거 친 표면은 유기 광전자 소자의 누설전류를 크게 증가시켜서 소자의 효율을 떨어뜨리기 때문에 이를 극복하는 기술의 개발이 시급한 실정이다. 본 연구에서는 UV 광 경화성 접착제를 이용하여 AgNW를 PET기판으로 transfer 시키는 방법으로 AgNW가 매몰된 유연 전도성 투명 기판을 제작하였으며, 이 기판은 낮은 표면 거칠기, 낮은 면저항과 높은 광투과도를 보여준다. 본 연구에서 개발된 AgNW가 매몰된 유연 전도성 투명 기판은 유기전자소자의 대체투명전극 으로 활용될 수 있는 가능성을 보여준다.

The purpose of this study was to examine new-silver women’s fiber and material property preferences and purchasing behaviors. The survey subjects were 115 new-silver women ranging in age from 50 to 60 years old. This study utilized a questionnaire as a measurement tool. The results of this study were as follows: First, the home ownership rate of the participants in this was 81.4%, and 54.9% of them had a bachelor’s degree or higher. Therefore, they turned out to be a new silver generation with higher education and stable income and assets. Second, regarding their purchasing behaviors, it was shown that they purchased the largest amount of clothing for themselves and their spouses, children, and grandchildren at the change of seasons. Third, with regard to their average spending on clothing, when they purchased clothing for themselves, it was shown that they purchased clothing at the price of KRW 500,000 or above for themselves but not for their family members. Fourth, their favorite type of fiber was synthetic fiber, and their favorite material property was heaviness, followed by roughness, stiffness, bulkiness, and glossiness. Moreover, with regard to their favorite functional textile, it was shown that the highest percentage of them preferred vitamin textiles, followed by ocher and scented textiles.

This study focuses on fabricating silver flake powder by a mechanical milling process and investigating the formation of flake-shaped particles during milling. The silver flake powder is fabricated by varying the mechanical milling parameters such as the amount of powder, ball size, impeller rotation speed, and milling time of the attrition ballmill. The particle size of the silver flake powder decreases with increasing amount of powder; however, it increases with increasing impeller rotation speed. The change in the particle size of the silver flake powder is analyzed based on elastic collision between the balls, taking energy loss of the balls due to the powder into consideration. The change in the particle size of the silver flake powder with mechanical milling parameters is consistent with the change in the diameter of the elastic deformation contact area of the ball, due to the collision between the balls, with milling parameters. The flake-shaped silver particles are formed at the elastic deformation contact area of the ball due to the collision. Keywords: Flake powder, Milling, Ball collision, Elastic deformation

In this study, the properties of Ag-coated TiO2 nanoparticles were observed, while varying the molar ratio of water and Ag+ for the surfactant and TiO2. According to the XRD results, each nanoparticle showed a distinctive diffraction pattern. The intensity of the respective peaks and the sizes of the nanoparticles increased in the order of AT1(R1 = 5)(33.3 nm), AT2 (R1 = 10)(38.1 nm), AT3(R1 = 20)(45.7 nm), AT4(R1 = 40)(48.6 nm) as well as AT5(R2 = 0.2, R3 = 0.5)(41.4 nm), AT6(R2 = 0.3, R3 = 1)(45.1 nm), AT7(R2 = 0.5, R3 = 1.5)(49.3 nm), AT8(R2 = 0.7, R3 = 2)(57.2 nm), which values were consistent with the results of the UV-Vis. spectrum. The surface resistance of the conductive pastes fabricated using the prepared Ag-coated TiO2 nanoparticles exhibited a range 7.0~9.0(274~328 μΩ/cm2) times that of pure silver paste(ATP)(52 μΩ/cm2).

Reduction in the amount of Ag salts in the membranes is required for practical applications in the industry. However, since the separation performance is directly related to the amount of Ag salts, it has been difficult to reduce the amount of Ag salts. In this study, we succeeded in preparing polymer/Ag salts/Al(NO3)3 membranes with 30% reduction in the amount of Ag salts by utilizing KIT-6, which is a porous material. When KIT-6 was incorporated into the polymer/Ag salts/Al(NO3)3 membrane, the separation performance for propylene/propane mixed gas increased with a propylene over propane selectivity of 20 and mixed gas permeance of 10 GPU. The enhanced separation performance is attributed to both the coordination of hydroxyl groups in KIT-6 with Ag ions and the porous properties of KIT-6.

This study analyzed the body-type characteristics of 340 old-aged obese women that had been on the rise as a part of efforts to activate the silver clothing industry. The subjects were in the age range of 60-79 and met some obesity requirements, including a Rohrer Index of 1.6 or higher, a BMI of 25 or higher, and a WHR of 0.85 or higher. Old-aged obese women showed increased thickness of the torso with age, which suggests that they revealed the characteristics of regardless of gender. In other words, they became bigger in the waist and abdomen, shorter in height, slimmer in the lower body, and thicker in the torso. There are three types of obesity: Type 1 is lower-body obesity with a higher degree of obesity in the abdomen than the upper body. Type 2 is abdominal obesity with a higher degree of obesity in the upper body than in the lower body. Type 3 is whole-body obesity with balanced obesity of the whole body. As for changes to the types of obesity according to age, those who are in their sixties usually fall into the categories of upper-body and whole-body obesity, and those who are in their seventies are much more concentrated in the categories of abdominal obesity and upper-body obesity with a decreased percentage of whole-body obesity. It is apparent that the percentage of abdominal and upper-body obesity rises with age due to fat accumulation in the abdomen.

One-dimensional (1D) silver nanostructures, which possess the highest conductivity among all room-temperature materials, moderate flexibility and high transmittance, are one of the most promising candidate materials to replace conventional indium tin oxide transparent electrodes. However, the short length and large diameter of 1D silver nanostructures cause a substantial decrease in the optical transparency or an increase in the sheet resistance. In this work, ultra-long silver nanofiber networks were synthesized with a low-cost and scalable electrospinning process, and the diameter of the nanofibers were finetuned to achieve a higher aspect ratio. The decrease in the diameter of the nanofibers resulted in a higher optical transparency at a lower sheet resistance: 87 % at 300 Ω/sq, respectively. It is expected that an electrospun silver nanofiber based transparent electrode can be used as a key component in various optoelectronic applications.

Korean society is aging at a fast rate and the ratio of elderly population is expected to increase by 38.2% in 2050 (Statistics Korea, 2011). The extension of average life expectancy of the elderly generation leads to various problems and the most important issue is the mental health of the elderly. The suicide rate of the elderly is increasing every year and is the highest rate among OECD nations (OECD, 2014). The primary reason for the rapidly increasing suicide rate is psychological hardship caused by personal, social, and environmental factors such as a generation gap from nuclearization, decreased social position, retirement, economic hardship, spousal bereavement, and separation. The importance of education to improve quality of life through the mental stability of the elderly generation is emphasized. Continued education has a positive effect on the physical, social, and psychological health of the elderly generation (Kim, 2011), successful aging (Jee, 2010), and quality of life (Kim &An, 2008). Arts and crafts education can achieve development in visual perception, sense of touch, and continued elderly education (Mo, 2011). Arts and crafts education improves accomplishments and creative thinking ability through analogue behavior of making by hand. This study conducted 12 hours of education for 3 days from 1pm to 5 pm at 1 week intervals on 5 elderly women between 55 and 70 years of age to investigate physical and psychological effects on elderly women through natural wool craft activity. Before the education, the anxiety degree of subjects of the past week was measured with the Beck Anxiety Inventory (BAI) to verify the effect of sensibility education by conducting electroencephalogram(EEG) and PortaLite before after conducting education on subjects. As a result of analyzing the before and after numerical mean value through brainwave test, the increasing phenomenon of an alpha waves appeared and showed that the psychology of subjects is stable and secure. The result of this study showed that wool craft education decreased anxiety, increased alpha waves and improved the psychological stability of elderly women.

본 연구에서는 크기와 형상이 서로 다른 4가지 실버 파우더를 이용하여 감광성 실버 페이스트를 제조 하였다. 제조된 실버 페이스트의 레올로지 특성 및 터치패널용 전도성 미세패턴 구현을 검토하였다. 그리고 건조방식에 따른 전도성도 평가하였다. 그 결과 실버 파우더의 평균입자 크기는 D50=0.8∼1.0㎛이 가장 낮은 저항치를 얻을 수 있었고, 또한 패턴의 Sharpness도 가장 우수함을 알 수 있었다. 건조방식은 예비건조 및 후 건조를 IR/IR방식으로 진행한 것이 가장 낮은 저항치를 얻을수있었다.

The silver nanoparticles (AgNPs) incorporated reverse osmosis (RO) membranes with an excellent antibacterial property has been reported. However, the incorporated AgNPs could increase the hydraulic resistance of membrane, indicating the decline of water flux. Here, hybrid silver nanoparticles (Ag@SiO2, 400 nm) were strongly immobilized using Ag-S chemical bonding on the polyamide surface of RO membrane for both protecting the decline membrane performance and having a strong antimicrobial property. The membrane performance was unchanged after the immobilization of silver nanoparticles, when compared to that of unmodified membrane. In addition, the silver-polyamide composite membrane significant reduced the number of live bacteria attached on the membrane surface by 92.7 ± 1.8, 99.5 ± 0.3, and 73.3 ± 5.5% for E. coli, P. aeruginosa, and S. aureus, respectively. The strong antimicrobial property is ascribed to the combination effect by the directly attachment to bacteria surface and the penetration of released silver ions inside the cell membrane of bacteria.

본 연구에서는 flake type hybrid silver powder와 poxy type hybrid binder로 그라비어 오프셋 인쇄용 실버 페이스트를 제조하였다. 제조된 실버 페이스트로 그라비어 오프셋인쇄법을 이용하여 30/30㎛(line/space) 를 연속적으로 300장 인쇄가 가능했다. 130℃에서 20분 동안 오븐에서 경화시켰을 때, 선저항은 약 10.4Ω㎝, 연필경도는 4H였다. 결론적으로 본 연구의 결과는 터치 패널용 narrow bezel전극으로 사용 가능함을 알 수 있었다.