NKN [(Na,K)NbO3] is a candidate lead-free piezoelectric material to replace PZT [Pb(Zr,Ti)O3]. A single crystal has excellent piezoelectric-properties and its properties are dependent of the crystal orientation direction. However, it is hard to fabricate a single crystal with stoichiometrically stable composition due to volatilization of sodium during the growth process. To solve this problem, a solid solution composition is designed (Na,K)NbO3-Ba(Cu,Nb)O3 and solid state grain growth is studied for a sizable single crystal. Ceramic powders of (Na,K)NbO3-M(Cu,Nb)O3 (M = Ca, Sr, Ba) are synthesized and grain growth behavior is investigated for different temperatures and times. Average normal grain sizes of individual specimens, which are heat-treated at 1,125 oC for 10 h, are 6.9, 2.8, and 1.6 m for M = Ca, Sr, and Ba, respectively. Depending on M, the distortion of NKN structure can be altered. XRD results show that (NKN-CaCuN: shrunken orthorhombic; NKN-SrCuN: orthorhombic; NKN-BaCuN: cubic). For the sample heat-treated at 1,125 oC for 10 h, the maximum grain sizes of individual specimens are measured as 40, 5, and 4,000 m for M = Ca, Sr, and Ba, respectively. This abnormal grain size is related to the partial melting temperature (NKN-CaCuN: 960 oC; NKN-SrCuN: 971 oC; NKN-BaCuN: 945 oC).

Objectives: Free Water Protocols (FWPs) are implemented selectively because of mixed evidence on the benefits associated with their use. This retrospective study examines the implementation a long-standing clinical program and descriptively reports rehabilitation and quality care outcomes. Methods: Data were collected over 6 years (n = 575). Inpatient rehabilitation setting. Variables included in this study were age, medical diagnoses, rate of acute care hospital transfers, discharge destinations, length of time on FWP. Results: Cohort consisted of older adults (M = 68.43, SD = 15.11), with diagnosis of stroke (60.2%), brain injury (19.1%), spinal cord injury (7.3%), cardiac (1%), orthopedics (5%), other (13.1%). Acute care hospital transfers occurred in 6% as descriptively compared to national average (14%). Additionally, participants tolerated FWP for days (M = 14.1, SD = 14.4) and most went home following rehabilitation Discussion: This retrospective study concludes the feasibility of implementing a FWP in a rehabilitation facility and reports descriptive outcomes. Experimental research is required for conclusions to be made regarding effectiveness of the FWP for dysphagia.

2-브로모에틸 에틸 에테르를 이용한 2-에티닐피리딘의 무촉매 중합을 통하여 측쇄에 에테르 부분을 갖는 새로운 공액구조 고분자를 합성하였다. 이 중합반응은 비교적 낮은 온도 조건에서도 균일하게 잘 진행 되었으며 89%의 수율로 해당 고분자를 합성할 수 있었다. NMR, IR, UV-visible 분광분석기 등을 이용하여 고 분자의 구조를 분석한 결과 설계한 치환기를 갖는 해당 고분자가 합성되었음을 확인할 수 있었다. 본 고분자는 물을 포함한 DMF, DMSO, DMAc, 메탄올 등의 유기 용매에 완전히 용해하였다. 합성 고분자의 전기화학적 특성과 광발광 특성을 측정하고 분석하였다.

In this paper, the dynamic snapping of the 3-free-nodes spatial truss model was studied. A governing equation was derived considering geometric nonlinearity, and a model with various conditions was analyzed using the fourth order Runge-Kutta method. The dynamic buckling phenomenon was observed in consideration of sensitive changes to the force mode and the initial condition. In addition, the critical load level was analyzed. According to the results of the study, the level of critical buckling load elevated when the shape parameter was high. Parallelly, the same result was caused by the damping term. The sensitive asymmetrical changes showed complex orbits in the phase space, and the critical load level was also becoming lowly. In addition, as the value of damping constant was high, the level of critical load also increases. In particular, the larger the damping constant, the faster it converges to the equilibrium point, and the occurrence of snapping was suppressed.

The design and fabrication of catalysts with low-cost and high electrocatalytic activity for the oxygen evolution reaction (OER) have remained challenging because of the sluggish kinetics of this reaction. The key to the pursuit of efficient electrocatalysts is to design them with high surface area and more active sites. In this work, we have successfully synthesized a highly stable and active NiCo2S4 nanowire array on a Ni-foam substrate (NiCo2S4 NW/NF) via a two-step hydrothermal synthesis approach. This NiCo2S4 NW/NF exhibits overpotential as low as 275 mV, delivering a current density of 20 mA cm-2 (versus reversible hydrogen electrode) with a low Tafel slope of 89 mV dec-1 and superior long-term stability for 20 h in 1M KOH electrolyte. The outstanding performance is ascribed to the inherent activity of the binder-free deposited, vertically aligned nanowire structure, which provides a large number of electrochemically active surface sites, accelerating electron transfer, and simultaneously enhancing the diffusion of electrolyte.

Carbon materials with tailorable structures and superior properties have great potential applications in environmental protection, energy conversion, and catalysis. Plant biomass as abundant and green non-toxic raw materials has been considered as good precursors for synthesizing heteroatom-doped carbon materials. However, few studies have been reported on the different natures of carbon materials derived from different parts of the same plant biomass. In this study, we prepared carbon materials from the petioles and blades of apricot leaves by direct pyrolysis without additives. Detailed characterizations indicate that these two carbon materials are similar in element composition and graphitization degree, but differ greatly in surface area and pore volume. These differences can be attributed to the different contents of inorganic salts, vascular bundles, and proteins in petioles and blades. When used as catalysts for the oxidation of ethylbenzene, the petiole-derived carbon shows better catalytic performance than the blades derived carbon due to its high surface area, large average pore size, and doped nitrogen atoms. Furthermore, the carbon catalysts derived from the petioles and blades of poplar leaves and parasol tree leaves show the same difference in catalytic reaction, implying that the above-mentioned conclusion is rather universal, which can provide reference for the synthesis of carbon materials from leaves.

지구상에서 가장 오래된 해양 미세조류로 알려진 스피룰리나는 인체에 필요한 영양성분을 대부분 함유하고 있는 것으로 알려져 있다. 그 구성성분으로는 phycocyanin, chlorophyll, β-carotene과 같 은 다양한 물질을 다량 함유한다고 보고되고 있으며, 노화 및 미백효과가 있다고 알려져 있다. 본 연구에서 는 스피룰리나 정제수 추출물의 UVB로 유도된 활성산소종 ROS (reactive oxygen species) 소거능과 항산 화능을 확인하였다. 스피룰리나 정제수 추출물 0.05, 0.10, 0.50 1.0 mg/mL의 DPPH 라디칼 소거능, FRAP 환원능 및 ABTS+ 라디칼 소거능을 측정하여 항산화효과를 확인하였다. 대체실험동물모델인 Zebrafish를 이용하여 스피룰리나 정제수 추출물을 0.05, 0.10, 0.50 mg/mL 농도로 처리하여 응고율, 부 화율, 심장독성을 측정하였으며, 스피룰라나 추출물을 0.05, 0.10, 0.50 mg/mL 농도로 처리한 후, DCFH-DA로 염색하여 UVB로 유도된 ROS 저해효과를 확인하였다. 항산화효과 측정 결과 양성대조군인 ascorbic acid와 비교시 DPPH, Frpa, ABTS 모두 농도 의존적으로 항산화 효과가 있음을 확인하였다. 대체 실험동물인 Zebrafish를 이용하여 응고율과 부화율, 심박수를 측정한 결과 0.5 mg/mL을 제외한 0.05, 0.10 mg/mL에서는 대조군과 비교 시 독성이 없음을 확인 하였다. UVB로 유도된 Zebrafish의 ROS 소거 능은 양성대조군에 비해 높은 ROS 감소 효과를 나타내었다. 본 연구의 결과는 스피룰라나 정제수 추출물 이 자외선 및 피부 보호 화장품 소재로 사용가치가 있음을 시사한다.

As water resources are limited and legal regulations are strengthened, there is a growing need to reuse residuals in WTP(Water Treatment Plant). In this study, membrane filtration system was constructed and its operation method was studied for water quality stabilization and reuse of WTP residuals. The operation parameters were stable for 1 year and 6 months. Membrane fouling was identified as particulate pollution (activated carbon) and inorganic pollution (manganese). The membrane system was operated steadily with raw water of high concentration SS(Suspended solid) containing activated carbon because membrane fouling was reduced by the effect of End-Free type. In the case of inorganic contamination, dissolved manganese eluted by chemicals and acted as a membrane fouling source, and the operating conditions for minimizing membrane fouling were confirmed by newly developing application methods and types of cleaning chemicals. Based on the results, design parameters for reducing manganese membrane fouling were derived.

Consumers want to express their original unique personality, and even are willing to endure high expenses in order to do this. One noticeable strategy in the market, used by companies to suit for this consumer sentiment, is that of employing limited edition marketing and limited free gifts. This study investigated the effects of limited free gifts on consumer response. Specifically, the present study examined how the need for uniqueness moderated the effects of limited free gifts on brand commitment and attitudes. The online survey method was used to gather the data and a total of 224 data were used to analyze data. The results of the research were as follows. The findings revealed four dimensions of limited free gifts: scarcity/specialty, not for sale, complementarity, and risk. Complementarity positively affected brand commitment, while all four dimensions of limited free gifts positively influenced brand attitude. In addition, the need for uniqueness was proven to be the strongest variable which positively influenced brand commitment and attitudes. Also, when the need for uniqueness was applied as a moderating variable, depending on the levels of the need for uniqueness, the effects of riskiness on the consumer’s response were shown to be different. The findings of this study infer various academic and practical applications.

Graphene has attracted the interest of many researchers due to various its advantages such as high mobility, high transparency, and strong mechanical strength. However, large-area graphene is grown at high temperatures of about 1,000 °C and must be transferred to various substrates for various applications. As a result, transferred graphene shows many defects such as wrinkles/ripples and cracks that happen during the transfer process. In this study, we address transfer-free, large-scale, and high-quality monolayer graphene. Monolayer graphene was grown at low temperatures on Ti (10nm)-buffered Si (001) and PET substrates via plasma-assisted thermal chemical vapor deposition (PATCVD). The graphene area is small at low mTorr range of operating pressure, while 4 × 4 cm2 scale graphene is grown at high working pressures from 1.5 to 1.8 Torr. Four-inch wafer scale graphene growth is achieved at growth conditions of 1.8 Torr working pressure and 150 °C growth temperature. The monolayer graphene that is grown directly on the Ti-buffer layer reveals a transparency of 97.4 % at a wavelength of 550 nm, a carrier mobility of about 7,000 cm2/V×s, and a sheet resistance of 98 W/□. Transfer-free, large-scale, high-quality monolayer graphene can be applied to flexible and stretchable electronic devices.

본 연구는 쿨롱마찰을 갖는 동적시스템의 기초적인 연구로써 단자유도계의 자유진동응답에 대한 닫힌 해를 제공하는 것을 목적으로 한다. 쿨롱마찰을 포함하는 동적시스템의 운동방정식은 운동방향에 따른 마찰력의 부호변화로 인하여 비선형 미분방정식의 형태로 표현되기 때문에 닫힌 형태의 해를 얻기가 매우 어려운 특성이 있다. 이를 해결하기 위한 기존의 방법으로는 수치적분법에 의해 비선형 미분방정식을 직접 계산하거나 또는, 쿨롱마찰에 의한 감쇠효과를 등가점성감쇠로 치환한 선형 미분방정식을 이용하여 간접적으로 해를 구하는 방법이 사용되고 있다. 그러나 이러한 방법들은 수학적인 측면에서 닫힌 해를 제공하지 않는다. 따라서 본 연구에서 는 운동방정식에서 반주기 구간마다 반전되는 마찰력의 부호변화를 고려하고, 이를 멱급수를 이용하여 전 구간으로 확장시킴으로써 쿨롱마찰을 고려한 단자유도계의 자유진동응답에 대해서 수학적으로 닫힌 해를 유도하였다. 또한, 마찰력의 크기가 강성에 의한 복 원력의 크기보다 커지는 순간에 자유진동 운동이 정지하는 조건을 이용함으로써 주어진 초기조건에 대해서 예측되는 자유진동 반주기의 수와 운동이 정지하는 순간의 정확한 응답 값을 제안하였다.

고구마 바이러스 무병묘의 기내급속증식을 위한 적정 생장 조절물질 및 sucrose 농도, 최소생장 기내보존(15°C)에 미치는 광의 영향과 생존율 및 기내생장 특성 등을 조사하였다. 고구마 무병묘의 마디배양은 0.2mg·L-1 BA 첨가배지에서 줄기신장, 줄기직경, 잎수, 뿌리수, 생체중 및 건물중 등이 가장 양호하였다. 배양부위 및 배지물리성에 따른 적정 sucrose 농도는 마디배양은 5% sucrose를 첨가한 고체배지에서, 정단배양은 3% sucrose를 첨가한 액체배지에서 줄기두께, 잎수, 뿌리수, 뿌리길이, 생체중 및 건물중 등의 생육에 가장 효과적이었다. 15°C 저온항온기에서 고구마 무병묘의 최소생장 기내보존은 암상태에서는 3개월 내에 모두 고사하였으나, 적색:청색(7:3) 혼합 LED (150±5μmol·m-2·s-1 PPFD)에서는 5개월까지 100% 생존하였다. 따라서 고구마 무병묘의 최소생장 기내보존에는 광이 필요하며, 샬레에 밀식(10 개체/샬레)할 경우, 좁은 공간에서 대량보존이 가능하였다.

Embryos produced with serum show the alterations in their ultrastructure, impaired compaction, abnormal blastulation, aberrant mRNA expression profiles and large calf syndrome with greater incidences of stillbirths and deaths after birth. The aim of the present study was to describe in vitro embryo production by analyzing embryo production, fetal production and pregnancy rate in free-serum medium. The OPU-IVP data used in this study from 2016. Approximately, sixteen cows (Hanwoo), which belonged to the Institute of Gyeongsang National University, were used. Two experimental group is used in this study. Serum groups were conducted in March to July and free-serum group was conducted in September to December. The recovered cumulus-oocyte complexes were morphologically classified to four grades based on the compaction of cumulus cells layers and homogeneity of the cytoplasm. The number of oocyte was significantly greater in serum groups than that in free-serum groups (29.61 ± 0.63 vs. 15.6 ± 0.62; p < 0.05). Between serum and free-serum groups indicate that average of 1st and 2nd grade oocytes were no difference (2.38 ± 1.67 vs. 2.38 ± 1.48; p > 0.05), but number of 3rd and 4th grade oocytes were greater in serum groups than that in free-serum groups (7.31 ± 7.64 vs. 5.60 ± 6.29; p < 0.05). Embryo cleaved competence was higher in rate in free-serum groups than that in serum groups (62.1% vs. 58.3; p < 0.05). However, blastocyst developmental rate was no difference between serum and free-serum groups (33.1% vs. 43.5%; p < 0.05). 986 recipients were used for embryo transfer. Pregnancy rate was indicated that between serum and free-serum group was no difference (54.6% vs. 56.3%; p < 0.05). In conclusion, we developed the free-serum system for production of in vitro bovine embryos in order to meet the developmental and qualitative requirements for large scale commercial use.