• 복식문화연구
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• 제25권6호
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• pp.880-892
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• 2017

In this study, the appearance change and the heat moisture transfer properties of knitted fabric by yarn shrinkage were examined to obtain useful data on the development of thermo-sensitive functional materials. Eleven types of knitted fabric were knitted using highly bulky acrylic-blended yarn. After shrinking the specimens using dry heat treatment, the appearance change and thickness were measured. An HEC simulator was adopted for measuring the heat moisture transfer properties of specimens by yarn shrinkage. When holes were arranged vertically in the mesh structure, the specimens with 2,500 and 5,000 holes showed high percent change of hole area, appearance, and thickness. When holes were diagonally arranged in the mesh structure, the percent change of hole area in the specimen with 1,250 holes was larger than the one with 2,500 holes. However, the dimensional stability of the specimen with 2,500 holes was better because of its smaller appearance and thickness change. In the tuck structure, the percent change of hole area in the specimen with 625 and 416 holes was relatively large compared with the appearance and thickness change. Furthermore, the hole size in the tuck structure was smaller than that in the mesh structure but the percent change of hole area was larger. Therefore, it was proved that the tuck structure is more suitable than the mesh structure for developing thermo-sensitive functional materials. Heat moisture transfer property test verified that the change of hole area by yarn shrinkage enabled obtaining the thermal effect due to the distinct temperature difference in the inner layer.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2585-2593
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• 2020

Swift heavy ion (SHI) beam irradiation can generate desirable defects in materials by transferring sufficient energy to the lattice that favours huge possibilities in tailoring of materials. The effect of Ag¹⁵⁺ ion irradiation with energy 200 MeV on spray deposited V₂O₅ thin films of thickness 253 nm is studied at various ion doses from 5 × 10¹¹ to 1 × 10¹³ ions/㎠. The XRD results of pristine film confirmed orthorhombic structure of V₂O₅ and its average crystallite size was found to be 20 nm. The peak at 394 cm^-1 in Raman spectra confirmed O-V-O bonding of V₂O₅, whereas 917 cm^-1 arise because of distortion in stoichiometry by a loss of oxygen atoms. Raman peaks vanished completely above the ion fluence of 5 × 10¹² ions/㎠. Optical studies by UV-Vis spectroscopy shows decrement in transmittance with an increase in ion fluence up to 5 × 10¹² ions/㎠. The red shift is observed both in the direct and indirect band gaps until 5 × 10¹² ions/㎠. The surface topography of the pristine film revealed sheath like structure with randomly distributed spherical nano-particles. The roughness of film decreased and the density of spherical nanoparticles increased upon irradiation. Irradiation improved the conductivity significantly for fluence 5 × 10¹¹ ions/㎠ due to band gap reduction and grain growth.

• Advances in nano research
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• 제10권5호
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• pp.449-460
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• 2021

Flexoelectricity is an interesting materials' property that is more touchable in small scales. This property beside the sandwich structures placed in the center of scientists' attention due to their extraordinary effects on the mechanical properties. Furthermore, in the passage of decades, more elaborated sandwich structures took into consideration results from using honeycomb core. This kind of structure, inspiring from honeycomb core, provides more stiffness to weight ratio, which plays a crucial role in different industries. In this paper, based on the Love-Kirchhoff's hypothesis, Hamilton's principle, modified couple stress theory and Fourier series analytical method, equations of motion for a sandwich plate containing a honeycomb core integrated by two face-sheets have derived and solved analytically. The equations of both face sheets have derived by flexoelectricity consideration. Moreover, it should be noticed that the whole structure rests on the visco-Pasternak foundation. Conducting current research provided an acceptable and throughout study based on flexoelectricity to address the effect of materials' characteristics, length-scale parameter, aspect, and thickness ratios and boundary conditions on the natural frequency of honeycomb sandwich plates. Also, based on the presented figures and tables, there is a close agreement between previous studies and recent work. Due to the high ratio of strength to weight, current model analyzing is capable of taking into account for different vehicles' manufacturing in a high range of industries.

• 한국환경농학회지
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• 제42권4호
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• pp.371-381
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• 2023

The effectiveness of plant-based attractants was studied using large traps, which attracted relatively more snails in agricultural water drainage ditches and rice-cultivating environments, although their effectiveness in rice fields and lakes was limited. The rate began to rise after three hours of observation. Watermelon peel exhibited the highest apple snail attraction rate (13.8%), followed by potatoes (10.0%), and apple peel (8.8%). These values significantly differed from the attraction rate attributed to papaya leaves (F=3.84; P=0.0387). After 24 h, watermelon peel and apple peel indicated a higher rate of attraction (23.4% and 21.7%, respectively), which were significantly different compared with those of papaya leaves and potatoes (F=9.94; P=0.00455). Large bait traps outperformed funnel traps in capturing golden apple snails and trapped a significant number of snails measuring over 1 cm in size. Watermelon peel was the most effective attractant for a large bait trap, followed by apple peel, potatoes, and papaya leaves. On average, 110 snails were captured in the lure net. However, potatoes, apple peels, and papaya leaves caught an average of 93, 80, and 79 snails, respectively. Among the attractants, the lure effect of the snails was not significantly different. The efficiency of large bait traps in capturing snails, regardless of the plant attractant employed, followed the order: apple peel > watermelon peel and potatoes > papaya leaves > melon > Korean melon. Watermelon peel is highly recommended for farmer use, as well as apple peel and potatoes. Utilizing these snail attractants may contribute positively to developing a safe and environment-friendly integrated pest management strategy.

• 한국수소및신에너지학회논문집
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• 제35권3호
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• pp.345-351
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• 2024

The unitized regenerative fuel cell (URFC) is a method that can reduce costs and increase system simplification by unitizing a fuel cell system and a water electrolysis system. The spray method is suitable as the membrane electrode assembly (MEA) manufacturing method for URFC because it is easy to control the amount of catalyst, the size of the system is small, and economical manufacturing is possible. In this study, a numerical analysis of the effect of solution concentration on the spray method was performed to use it as basic data for the spray method to be used in MEA manufacturing. As result, as the Nafion solution concentration decreases it was found that the spray speed and the mass flow rate and the discrete phase model concentration increases and the spray range widens.

• 자연과학논문집
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• 제14권1호
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• pp.83-121
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• 2004

본 연구는 영농규모화에 대한 전개과정과 충남지역 쌀 생산기반을 검토하고 쌀 산업의 미래지향적 방향의 한 축을 이어갈 쌀 전업농의 영농규모화를 통한 그 대안을 모색하는데 있다. 이 목적을 완성하기 위해 조사된 내용을 요약하면 다음과 같다. 1. 충남지역이 쌀 생산은 전국에서 가장 높으며 재배면적에서도 제2위를 차지하고 있다. 이는 그만큼 쌀에 대한 국제적 정세변화는 충남의 쌀 생산농가에게 지대한 영향을 미칠 수 있는 개연성을 높여준다. 쌀 생산의 핵심이 되는 전업농가 수는 도내 전체농가의 7.7%를 차지하고 있고, 이들의 평균 경작면적은 2.9ha 이다. 이 면적은 규모화사업을 위해 지원된 자금이 크게 주효한 결과라고 해석된다. 2. 1980년대 후반부터 2002년까지 추진된 충남지역 영농규모화사업은 충남지역에 쌀 전업농가의 경영규모를 19,484ha까지 증가시켰다. 또한 1995년부터 2002년까지 매매사업이 이루어진 농가 수는 6,431농가에 1,6517ha가 매매되었으며, 장기임대차사업은 같은 기간동안 7,059농가에 면적은 6,970ha에 이르렀다. 다만 농지교환분합사업은 210ha에 1,864농가가 참여하였는데 이처럼 농지교환.분합사업이 활발하지 못한 것은 은퇴자들이 영농에 넓은 면적을 요망하지 않아 구태여 규모화사업에 응하지 않더라도 생활에 지장이 없기 때문이다. 또한 교환과 분합작업에 따른 복잡성 등, 일반 사회적 여건도 농지의 교환분합사업에 부정적인 방향으로 작용했던 것으로 추정된다. 3. 영농규모화사업을 촉진하기 위해서 제안된 방안들은 다음과 같다. (1) 재촌탈농자 및 고령 은퇴자를 위한 전직 프로그램 및 사회보장프로그램을 수립하고 농지매매 촉진을 위한 각종 인센티브제를 도입하여야 할 것이다. (2) 효율적인 쌀 생산시스템을 확립하기 위하여 단위면적당 생산량을 증대시키고 생산비를 낮추는 제 방안이 강구되어야 한다. 이를 위해서는 쌀 생산기술과 경영적 능력을 갖춘 생산조직이 육성되어야 하며 시설의 적정배치 및 정보화가 완비되어야 한다. 그리고 영농시스템 구축에 바탕을 둔 지역종합의 다양한 구조개선도 병행하지 않으면 안 될 것이다. (3) 경영규모를 확대, 개선하기 위해서는 개별경영규모를 확대하거나 집단규모를 활용한 방안이 강구될 수 있을 것이다. 이상을 종합하면 충남의 영농규모화사업은 성공적으로 수행되어 왔다고 할 수 있으나, 궁극적으로 이 사업이 소기의 목적을 달성하기 위해서는 부수되는 제반 문제점을 적절히 해결해 가지 않으면 안 된다. 그리고 쌀 전업농에 대한 적절한 지원 및 탈농자 및 은퇴자에 대한 종합대책수립은 충남의 영농규모화사업을 완수하는데 반드시 선결되어야할 사항이다.

• 대한한의학회지
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• 제19권1호
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• pp.234-250
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• 1998

Bujeonghangamtang(扶正抗癌湯) has been used for cure of tumor as a traditional medicine without any experimental evidence to support the rational basis for its clinical use. This study was carroed out to evaluate the possible therapeutic or antitumoral effects of Bujeonghangamtang extract against tumor, and to carry out some mechanisms responsible for its effect. Some kinds of tumor were induced by .the typical application of 3-methylcholanthrene (MCA) or by the implantation(s.c) of malignant tumor cells such as leukemia cells(3LL cells) or sarcoma cells(Sl80 cells). Treatment of the Bujeonghangamtang water-extract (dailly 1mg/mouse, i. p.) was continued for 7 days prior to tumor induction and after that the treatment was lasted for 20 days. Against squamous cell carcinoma induced by MCA, Bujeonghangamtang decreased not only the frequency of tumor production but also the number and the weight of tumors per tumor bearing mice (TBM). Bujeongmngamtang also significantly suppressed the development of 3LL cell and S180 cell-implanted tumors in occurence-frequency and their size, and some developed tumors were regressed by the continuous treatment of Bujeonghangamtang extract into TBM. In vitro, treatment of Bujeonghangamtang extract had no effect on the growth of some kinds of cell line such as FsaII, A431 strain but significantly inhibited the proliferation of 3LL, S180 cells and augmented the DNA synthesis of mitogen-activated lymphocytes. Bujeonghangamtang also stimulated the migrative ability of leukocyte, the MIF and IL-2 production of T lymphocytes, but not IL 6 production of B cells. Bujeonghangamtang-administration to mice enhanced NK cells attivities. These results demonstrated that Bujeonghangamtang extract exhibited a significant prophylactic benefits against tumors and its antitumor activity was manifested depending on the type of tumor cells. And these results also suggested that effect of Bujeonghangamtang might be chiefly due to nonspecific enhancement of NK cell activities and cell-mediated immune responses.

• Journal of Ginseng Research
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• 제46권2호
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• pp.255-265
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• 2022

Background: Ginsenoside Rb1, a bioactive component isolated from the Panax ginseng, acts as a remedy to prevent myocardial injury. However, it is obscure whether the cardioprotective functions of Rb1 are related to the regulation of endogenous metabolites, and its potential molecular mechanism still needs further clarification, especially from a comprehensive metabolomics profiling perspective. Methods: The mice model of acute myocardial ischemia (AMI) and oxygen glucose deprivation (OGD)-induced cardiomyocytes injury were applied to explore the protective effect and mechanism of Rb1. Meanwhile, the comprehensive metabolomics profiling was conducted by high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (HPLC-Q/TOF-MS) and a tandem liquid chromatography and mass spectrometry (LC-MS). Results: Rb1 treatment profoundly reduced the infarct size and attenuated myocardial injury. The metabolic network map of 65 differential endogenous metabolites was constructed and provided a new inspiration for the treatment of AMI by Rb1, which was mainly associated with mitophagy. In vivo and in vitro experiments, Rb1 was found to improve mitochondrial morphology, mitochondrial function and promote mitophagy. Interestingly, the mitophagy inhibitor partly attenuated the cardioprotective effect of Rb1. Additionally, Rb1 markedly facilitated the phosphorylation of AMP-activated protein kinase α (AMPKα), and AMPK inhibition partially weakened the role of Rb1 in promoting mitophagy. Conclusions: Ginsenoside Rb1 protects acute myocardial ischemia injury through promoting mitophagy via AMPKα phosphorylation, which might lay the foundation for the further application of Rb1 in cardiovascular diseases.

• 벤처창업연구
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• 제16권6호
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• pp.287-297
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• 2021

본 연구는 고객만족의 매개효과를 통해 고객충성도를 결정짓는 주요 요인을 연구하는 것이다. 또한 고객이 전통적인 자금이전과 은행에서 핀테크로 전환하는 이유를 살펴보고자 하였다. 이 연구에서 제시된 소비자 선택은 국경 간 자금거래에서 모바일 핀테크를 선택하는 요인에 대하여 알 수 있었다. 특정 요인에 대한 소비자 선호도를 추정할 수 있는 결합분석 접근방식을 사용하였다. 또한 모바일 결제 서비스를 사용하는 핀테크의 주요 속성이 선택에 미치는 영향에 대한 소비자 평가를 조사하였다. 이 연구에서는 국경 간 지불을 위해 정기적으로 모바일 핀테크를 사용하는 348명의 표본을 대상으로 분석하였다. 신뢰도와 매개효과를 검증하기 위해 SPSS 26을 사용하였다. 모든 설문지는 고객이 해외 송금을 위해 기존 은행 대신 핀테크를 사용하는 소비자들을 대상으로 연구하였다. 연구 결과 서비스 품질, 고객의 신뢰, 제품 품질은 고객의 만족도에 유의한 영향을 미치는 것으로 나타났다. 국가간 핀테크 결제거래에서 고객들의 충성도와 만족도를 높이기 위해서는 서비스 품질, 고객 신뢰 및 제품 품질에 보다 중점을 두어야 한다는 시사점을 얻을 수 있었다.

• 대한치과보철학회지
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• 제51권4호
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• pp.261-268
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• 2013

연구 목적: 본 연구는 납형의 크기 및 형태 변화가 티타늄의 주조성에 어떠한 영향을 미치는지 확인하고자 하였다. 연구 재료 및 방법: 납형의 크기에 따라 Small Pattern군과 Large Pattern군으로 나누었고, 각각 Flat, Semicircular, Horse-shoe 및 V-shape형으로 납형의 형태에 따라 4개의 하위군으로 나누어 총 8개의 군으로 분류하였다. 모든 납형의 주입선은 Runner-bar형으로 하였다. 티타늄 주조 전용 매몰재인 실리카계 매몰재(Rematitan Plus$^{(R)}$, Dentarum, Germany)를 이용하여 매몰하였고, 아크용융 방식의 원심 주조기(Ti Cast Super R$^{(R)}$, Selec, Japan)를 사용하여 주조하였다. 주조성 평가는 완전한 형태로 주조 된 격자의 개수를 척도로 재현 정도를 확인하였다. 통계처리는 SPSS ver. 19.0 for WIN (SPSS. Inc. Chicago, IL, USA)를 사용하였다. 납형의 크기 및 형태에 따른 티타늄의 주조성을 이원변량 분산분석(Two-way ANOVA)을 이용하여 분석하였다. 결과:납형의 평균 재현율은 Small Pattern군은 95.14%, Large Pattern군은 94.30%로 Small Pattern군의 주조성이 유의하게 높았다(P<.05). 납형의 형태 변화에 따른 주조성은 Small Pattern군에서 Semicircular군 133.20개(96.52%), Horse-shoe군 132.40개(95.94%), Flat군 132.00개(95.65%), V-shape군 127.60개(92.46%) 순으로 감소하였다. Large Pattern군은 Flat군 198.60개(95.94%), V-shape군 197.80개(95.56%), Semicircular군 196.40개(94.88%), Horse-shoe군 188.00개(90.82%)순으로 감소하였다. Small Pattern군과 Large Pattern군 모두에서 납형의 형태변화에 따른 주조성은 유의할 만한 차이를 보이지 않았다(P>.05). 결론:주조체의 크기가 작을수록 주조성이 높아짐을 알 수 있었고 형태에 따른 주조성에서는 큰 영향을 받지 않는 것을 알 수 있었다.