본 연구에서는 폴리비닐알콜(PVA)와 폴리프로필렌글리콜(PPG)기반의 창상피복용 수분산 폴리우레탄수지를 합성하였으며, 시료의 물리적 특성을 필름 시료와 피혁(Full-Grain) 표면에 코팅을 하여 물리적 특성 변화를 연구하였다. 인장강도의 경우 PVA가장 적게 반응된 PUD-PA1 2.00 kgf/㎟ 으로 가장 높은 저항성을 보였으며. 마찬가지로 연실율은 PVA가장 적게 반응된 PUD-PA1가 554%로 높게 측정되었다. 내마모성 측정 결과 PVA 반응이 증가함에 따라 표면의 강도나 낮게 36.77 ㎎.loss로 감소 됨을 알수 있었다.

목적 : 본 연구는 정확한 처방에 의한 근용 안경 사용의 필요성을 알아보기 위하여 기성돋보기를 사용하고 있는 사람들을 대상으로 기성돋보기 사용자들의 변수를 측정하여 비교 분석하였다. 방법 : 연구대상자는 45세 이상 기성돋보기를 사용 중인 총 50명을 선정하여, 굴절검사와 최대조절력, 근용가입도, 근용 PD를 측정하였다. 또한, 사용 중인 기성돋보기 안경테 기준점간 거리와 안경렌즈 광학중심점간 거리를 측정하였다. 결과 : 기성돋보기의 구입 시기에 따른 가장 선명한 거리를 확인한 결과 구입 시기가 오래될수록 선명한 거리가 길어졌다. 기성돋보기의 안경테 기준점간 거리와 광학중심점간 거리를 비교한 결과 안경테의 기준점간 거리가 클수록 광학중심점간 거리도 커졌고, 광학중심점간 거리와 근용 PD가 2 mm 이상 차이가 나는 경우가 71.00% 인 것으로 나타났다. 또한, 양안시에 영향을 미치는 유발 프리즘을 확인한 결과 80.00%에서 BO △, 16.00%에서 BI △이 유발되는 것으로 나타났다. 결론 : 본 연구로 기성돋보기 안경과 실제 처방 근용 안경의 굴절력과 PD 차이로 양안시에 유발되는 사위로 인한 안정피로를 확인 할 수 있었다. 따라서, 눈 건강에 악영향을 미칠 수 있는 기성돋보기 사용을 예방하기 위하여 온라인을 포함한 기성돋보기 안경의 판매 기준과 안경사의 전문성 강화를 통해 국민 안보건 서비스의 질적 향상이 필요하다.

Dry etching of copper thin films is performed using high density plasma of ethylenediamine (EDA)/ hexafluoroisopropanol (HFIP)/Ar gas mixture. The etch rates, etch selectivities and etch profiles of the copper thin films are improved by adding HFIP to EDA/Ar gas. As the EDA/HFIP concentration in EDA/HFIP/Ar increases, the etch rate of copper thin films decreases, whereas the etch profile is improved. In the EDA/HFIP/Ar gas mixture, the optimal ratio of EDA to HFIP is investigated. In addition, the etch parameters including ICP source power, dc-bias voltage, process pressure are varied to examine the etch characteristics. Optical emission spectroscopy results show that among all species, [CH], [CN] and [H] are the main species in the EDA/HFIP/Ar plasma. The X-ray photoelectron spectroscopy results indicate the formation of CuCN compound and C-N-H-containing polymers during the etching process, leading to a good etch profile. Finally, anisotropic etch profiles of the copper thin films patterned with 150 nm scale are obtained in EDA/HFIP/Ar gas mixture.

Processing and characterization of graphene (Gr)-reinforced aluminium alloy 7075 (AA7075) microcomposites and nanocomposites are reported in this work. Composites are fabricated by mechanical alloying process at wet conditions. The bulk composites are prepared by uniaxial die pressing to get higher densification and sintered in an inert atmosphere. Density of the nanocomposites is higher than the microcomposites due to the reduction of grain size by increased milling time. X-ray diffraction (XRD) analysis confirms graphene interaction with the AA7075 matrix lattice spaces. The effective distribution of graphene with aluminium alloy is further confirmed by the Transmission Electron Microscopy (TEM) analysis. The hardness of the composites proportionally increases with the graphene addition owing to grain refinement. Wear morphology is characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Microcomposites reveal abrasive and ploughing wear mechanism of material removal from the surface. Nanocomposites show adhesive wear with delamination and particle pull-out from the material surface.

This study investigated the effect of the addition of various levels of pig head meat (HM) as a substitute for rear leg meat (RLM) on the physico-chemical quality characteristics of non-emulsified, smoked, and cooked sausage during refrigerated storage. Sausages were prepared in four variations according to the proportion (0%, 10%, 20%, or 30%) of HM added and maintained at 4°C. Quality measurements were taken for 28 days. The sausages added with the addition of 20% and 30% HM had significantly (p<0.05) higher moisture and lower protein content compared to those without the addition of HM. The pH value during the storage period was higher (p<0.05) in the sausages to which the HM had been added than in those without HM. The sausages with 30% HM showed the lowest (p<0.05) L* and b* values and the highest (p<0.05) a* value during the storage period. The 2-thiobarbituric acid reactive substances (TBARS) content, hardness, cohesiveness, springiness, gumminess, and chewiness of the sausages showed no significant variations with the addition of various levels of HM. These data suggest that RLM could be substituted with 30% HM because it does not negatively affect the quality of the non-emulsified sausage. However, a further study on sausages made with 100% HM instead of RLM may be needed to improve its utilization.

The surface of silicon dummy wafers is contaminated with metallic impurities owing to the reaction with and adhesion of chemicals during the oxidation process. These metallic impurities negatively affect the device performance, reliability, and yield. To solve this problem, a wafer-cleaning process that removes metallic impurities is essential. RCA (Radio Corporation of America) cleaning is commonly used, but there are problems such as increased surface roughness and formation of metal hydroxides. Herein, we attempt to use a chelating agent (EDTA) to reduce the surface roughness, improve the stability of cleaning solutions, and prevent the re-adsorption of impurities. The bonding between the cleaning solution and metal powder is analyzed by referring to the Pourbaix diagram. The changes in the ionic conductivity, H2O2 decomposition behavior, and degree of dissolution are checked with a conductivity meter, and the changes in the absorbance and particle size before and after the reaction are confirmed by ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) analyses. Thus, the addition of a chelating agent prevents the decomposition of H2O2 and improves the life of the silicon wafer cleaning solution, allowing it to react smoothly with metallic impurities.

This study aimed to investigate the antioxidant activities and quality characteristics of jelly added with Orostachys japonicus juice. The moisture content and the soluble solids content of the jelly samples decreased significantly with increasing content of O. japonicus. The pH was highest in the control samples, and the pH significantly decreased with the addition of increasing amounts of O. japonicus. In terms of the chromaticity measurements, the lightness value and redness value was highest in the control sample, and it decreased as the amount of added O. japonicus increased, whereas the yellowness value increased with increasing levels of O. japonicus added. The gumminess and chewiness of the jelly increased with the addition of increasing amounts of O. japonicus. On the other hand, the cohesiveness and adhesiveness of the jelly did not show statistically significant changes. The total polyphenol and DPPH radical scavenging activities of the jelly with 100% O. japonicus added were significantly higher than those of the jelly with 0% O. japonicus added. Regarding the sensory evaluation, the sample with 75% O. japonicus added was perceived to have the best color, flavor, O. japonicus flavor, chewiness, and overall preference.

This study was conducted to effectively supplement vitamin D and increase the consumption of ear mushroom based on the investigation of the quality characteristics of cookies containing ear mushroom supplemented with vitamin D. Cookies were made of 0%, 1%, 3%, and 5% ear mushroom powder treated by ultraviolet B. Increased addition of ear mushroom powder led to a decrease in the bulk density of the dough as well as a spread factor, color value, and hardness of the cookies. There was no significant difference in the loss rate, but the water content of the dough and cookies was increased. The total polyphenol content of cookies added with 1~5% ear mushroom powder was higher than that of the 0%. The DPPH free radical scavenging activity of cookies added with 5% ear mushroom powder (23.8%) was 2 times higher than that of the 0% (10.9%). The vitamin D2 content of cookies added with 5% ear mushroom powder (835.5 μg/100 g D.W.) was 44 times higher than that of the 0% (19.0 μg/100 g D.W.). Consequently, ear mushroom powder is considered to be suitable for the production of functional cookies because of high values of antioxidant activity and vitamin D2 content.

Effects of Sc addition on microstructure, electrical conductivity, thermal conductivity and mechanical properties of the as-cast and as-extruded Al-2Zn-1Cu-0.3Mg-xSc (x = 0, 0.25, 0.5 wt%) alloys are investigated. The average grain size of the as-cast Al-2Zn-1Cu-0.3Mg alloy is 2,334 μm; however, this value drops to 914 and 529 μm with addition of Sc element at 0.25 wt% and 0.5 wt%, respectively. This grain refinement is due to primary Al3Sc phase forming during solidification. The as-extruded Al-2Zn-1Cu-0.3Mg alloy has a recrystallization structure consisting of almost equiaxed grains. However, the asextruded Sc-containing alloys consist of grains that are extremely elongated in the extrusion direction. In addition, it is found that the proportion of low-angle grain boundaries below 15 degree is dominant. This is because the addition of Sc results in the formation of coherent and nano-scale Al3Sc phases during hot extrusion, inhibiting the process of recrystallization and improving the strength by pinning of dislocations and the formation of subgrain boundaries. The maximum values of the yield and tensile strength are 126 MPa and 215 MPa for the as-extruded Al-2Zn-1Cu-0.3Mg-0.25Sc alloy, respectively. The increase in strength is probably due to the existence of nano-scale Al3Sc precipitates and dense Al2Cu phases. Thermal conductivity of the as-cast Al-2Zn-1Cu-0.3Mg-xSc alloy is reduced to 204, 187 and 183 W/MK by additions of elemental Sc of 0, 0.25 and 0.5 wt%, respectively. On the other hand, the thermal conductivity of the as-extruded Al-2Zn-1Cu-0.3Mg-xSc alloy is about 200 W/Mk regardless of the content of Sc. This is because of the formation of coherent Al3Sc phase, which decreases Sc content and causes extremely high electrical resistivity.

Conductive polymer composites with high electrical and mechanical properties are in demand for bipolar plates of phosphoric acid fuel cells (PAFC). In this study, composites based on natural graphite/fluorinated ethylene propylene (FEP) and different ratios of carbon black are mixed and hot formed into bars. The overall content of natural graphite is replaced by carbon black (0.2 wt% to 3.0 wt%). It is found that the addition of carbon black reduces electrical resistivity and density. The density of composite materials added with carbon black 3.0 wt% is 2.168 g/cm3, which is 0.017 g/cm3 less than that of non-additive composites. In-plane electrical resistivity is 7.68 μΩm and through-plane electrical resistivity is 27.66 μΩm. Compared with non-additive composites, in-plane electrical resistivity decreases by 95.7 % and through-plane decreases by 95.9 %. Also, the bending strength is about 30 % improved when carbon black is added at 2.0 wt% compared to non-additive cases. The decrease of electrical resistivity of composites is estimated to stem from the carbon black, which is a conductive material located between melted FEP and acts a path for electrons; the increasing mechanical properties are estimated to result from carbon black filling up pores in the composites.

The carbon anode material for lithium-ion battery was prepared by pyrolysis fuel oil and waste polyethylene terephthalate (PET) additive. The pitch was synthesized as a medium material for carbon anode by heat treatment. The waste PET additive improved the softening point and thermal stability of the pitch. La and Lc of the anode material (heat-treated pitch) increased at higher treatment temperature but decreased by waste PET additive. The electric capacity was evaluated based on effects of defective cavity and developed graphite interlayer, respectively. When the La and Lc of the anode material decreased, the electric capacity by cavity increased based on defective graphite structure. Therefore, the addition of waste PET causes the improved capacity by the cavity. The anode material which has a high efficiency (over 95%) and C-rate (95%, 2 C/0.1 C) was obtained by controlling the process of heat treatment and PET addition. The mechanism of lithium-ion insertion was discussed based on effects of defective cavity and developed graphite interlayer.

목적 : 한국 성인의 누진굴절력렌즈 사용현황 분석을 통해 누진굴절력렌즈 착용자의 정시안과 비정시안의 비율 과 변화추이를 살펴보고 그들이 착용하는 가입도를 분석하였다. 원용굴절력과 가입도와의 상관관계를 분석하고 유의성을 살펴봄으로써 가입도와 관련하여 누진굴절력렌즈 처방에 참고가 될만한 기초자료를 제공하고자 연구를 시작하였다. 방법 : 2014년도부터 2018년도까지 경기와 수도권 지역 안경원에서 처방한 최근 5년간의 누진굴절력렌즈 처 방현황을 바탕으로 한국 성인의 누진굴절력렌즈 사용변화 추이를 파악해보았다. 원거리 굴절이상안의 분류는 등가 구면굴절력(spherical equivalent = spherical + cylinder/2)을 기준으로 근시안, 정시안, 원시안, 난시안으로 분 류했다. 누진굴절력렌즈를 착용하는 한국성인의 원용굴절력과 가입도의 상관성을 분석하였다. 결과 : 원거리 굴절이상도와 가입도간의 상관관계를 분석한 결과, 근시 r=0.070, p＜0.010, 원시 r=0.150, p ＜0.010, 난시 r=0.092, p＜0.010으로 나타났다. 굴절이상도와 가입도간의 상관계수는 근시, 난시, 원시의 순으 로 높게 나타났다. 결론 : 노안은 현대사회에서 피할 수 없는 현실이다. 노안을 해결하는 가장 좋은 방법은 누진굴절력렌즈를 착용하 는 것이다. 그러나 한국에서의 누진굴절력렌즈 착용 비율은 해외에 비해 저조한 편이다. 본 연구에 기초했을 때, 누진굴 절력렌즈 처방시 굴절이상도와 가입도의 관계를 고려해야 할 것으로 판단된다. 또한 누진굴절력렌즈에 잘 적응하여 만족스러운 시생활을 영위하기 위해서는 누진굴절력렌즈의 초기착용를 권장하는게 바람직하다고 여겨진다. 그리고 정기 적인 굴절검사의 진행과 함께 누진굴절력렌즈의 적응방법에 관한 체계적인 교육이 필요하다고 사료된다.

Amniotic membrane stem cells are considered as a good alternative to embryonic stem cells, but their use in clinical studies is still not common. Here, exosomes from canine amniotic membrane mesenchymal stem cells (cAmMSCexo) were used for dog sperm cryopreservation. Upon cryopreserved straws using cryoprotectant containing 0, 0.5, 1, or 2 μg/mL of cAmMSC-exo were thawed, motility and membrane integrity were analyzed. However, results showed no significant differences between the groups. We concluded that cAmMSC-exo with lower than 2 µg/mL have no effects on sperm cryopreservation, and further studies to get higher concentrations of cAmMSC-exo should be conducted for clinical application.

In this study, the effects of kaolin addition on the properties of reticulated porous diatomite-kaolin composites are investigated. A reticulated porous diatomite-kaolin composite is prepared using the replica template method. The microstructure and pore characteristics of the reticulated porous diatomite-kaolin composites are analyzed by controlling the PPI value (45, 60, and 80 PPI) of the polyurethane foam (which are used as the polymer template), the ball-milling time (8 and 24 h), and the amount of kaolin (0–50 wt. %). The average pore size decreases as the amount of kaolin increases in the reticulated porous diatomite-kaolin composite. As the amount of kaolin increases, it can be determined that the amount of inter-connected pore channels is reduced because the plate-shaped kaolin particles connect the gaps between irregular diatomite particles. Consequently, a higher kaolin percentage affects the overall mechanical properties by improving the pore channel connectivity. The effect of kaolin addition on the basic properties of the reticulated porous diatomite-kaolin composite is further discussed with characterization data such as pore size distribution, scanning electron microscopy images, and compressive strength.

The Nannophya species in Korea was thought to consist of only Nannophya pygmaea. Previous studies on the species, including life history and development, conservation and restoration, habitat characteristics, genetic studies, distribution, behavior, and taxonomy have been conducted. However, a new Nannophya species, Nannophya koreana, was recently discovered in Korea. Moreover, this new species was found to inhabit both Korea and Japan. Thus, the previous studies should be reevaluated in relation to the new species, Nannophya koreana, and the latter should be treated as an endangered species worldwide given the current population instability.

This study investigated the quality characteristics of black soybean sediments to diversify the availability of soybean. The cooking method selected for black soybean sediment preparation was a pressure cooking process without soaking, considering the isoflavone content. The black soybean sediments were prepared by the addition of 0, 10, 30, 50 and 100% (w/w) black soybean. When 0% to 100% black soybean was added to the black soybean sediments, the moisture and crude protein contents increased from 53.17% to 54.41% and from 12.07% to 21.68%, respectively. The total isoflavone content of the black soybean sediments was increased from 2.69 μg/g to 696.09 μg/g, respectively, by the addition of black soybean. The anthocyanin content of the black soybean sediments ranged from 279.29 μg/g to 387.8 μg/g by the addition of black soybean. The total polyphenol content and the total flavonoid content of the black soybean sediments range from 1.72 mg/g to 2.00 mg/g and 0.89 mg/g to 0.92 mg/g, respectively, by the addition of black soybean. Given the isoflavones, total polyphenol, and anthocyanin content of the black soybean sediments, it is appropriate that the ratio of added black soybeans is at least 50% after the pressure-cooking process, regardless of soaking.