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        검색결과 85

        1.
        2023.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effects of La3+ substitution for Sr2+-site on the crystal structure and the dielectric properties of (Ba0.7Sr0.3-3x/2Lax) (Ti0.9Zr0.1)O3 (BSLTZ) (0.005 ≤ x ≤ 0.02) ceramics were investigated. The structural characteristics of the BSLTZ ceramics were quantitatively evaluated using the Rietveld refinement method from X-ray diffraction (XRD) data. For the specimens sintered at 1,550 °C for 6 h, a single phase with a perovskite structure and homogeneous microstructure were observed for the entire range of compositions. With increasing La3+ substitution (x), the unit cell volume decreased because the ionic size of La3+ (1.36 Å) ions is smaller than that of Sr2+ (1.44 Å) ions. With increasing La3+ substitution (x), the tetragonal phase fraction increased due to the A-site cation size mismatch effect. Dielectric constant (εr) increased with the La3+ substitution (x) due to the increase in tetragonality (c/a) and the average B-site bond valence of the ABO3 perovskite. The BSLTZ ceramics showed a higher dielectric loss due to the smaller grain size than that of (Ba0.7Sr0.3)(Ti0.9Zr0.1)O3 ceramics. BSLTZ (x = 0.02) ceramics met the X7R specification proposed by the Electronic Industries Association (EIA).
        4,000원
        3.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study focuses on how the partial substitution of copper by nickel nanoparticles affects the electrical and structural properties of the Bi2Ba2Ca2Cu2.9Ni0.1O10+δ, Bi2Ba2Ca2Cu2.8Ni0.2O10+δ and Bi2Ba2Ca2Cu2.6Ni0.4O10+δ compounds. Approximate values of crystallization size and crystallization percentage for the three compounds were calculated using the Scherer, modified Scherer, and Williamson-Hall methods. A great similarity was observed in the crystal size values from the Scherer method, 243.442 nm, and the Williamson-Hall method, 243.794 nm for the second sample. At the same time this sample exhibited the highest crystal size value for the three methods. In the examination of electrical properties, the sample with 0.1 partial substitution, Bi2Ba2Ca2Cu2.9Ni0.1O10+δ was determined to be the best with a critical temperature of 100 K and an energy gap of 6.57639 × 10-21 MeV. Using the SEM technique to analyze the structural morphology of the three phases, it was discovered that the size of the granular forms exceeds 25 nm. It was determined that the samples’ shapes alter when nickel concentration rises. The patterns that reveal the distribution of the crystal structure also exhibit clear homogeneity.
        4,000원
        5.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The purpose of this study is to confirm the thermal expansion characteristics of concrete mixed with 1% waste glass fine aggregates, which is the amount stipulated for recycled aggregates in the current quality standard. METHODS : The coefficient of thermal expansion was measured by applying AASHTOT 336-10 using a LVDT. The results measured were used as physical properties in a finite element analysis to confirm the change in tensile stress and the displacement of the right angle section of the upper slab of a concrete pavement due to admixture substitution. RESULTS : The thermal expansion coefficients of concrete based on the replacement rate of the admixture when the waste glass fine aggregates are replaced are within the range of the thermal expansion coefficients of concrete specified in the Federal Highway Administration report. As the replacement rate of the admixture increases, the thermal expansion coefficient of concrete decreases. As the thermal expansion coefficient decreases, the slab pavement curling displacement and the tensile stress of the center of the upper slab of concrete decrease. CONCLUSIONS : In the short term, the presence or absence of waste glass fine aggregates does not significantly affect the thermal expansion coefficient of concrete. However, in the long term, waste glass fine aggregates are reactive aggregates that causes ASR, which creates an expandable gel around the aggregates and results in concrete expansion. Therefore, the relationship between ASR and the thermal expansion coefficient must be analyzed in future studies.
        4,000원
        6.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To develop quality-improved muffins, the influence of the partial replacement of wheat flour with lemon balm powder (LBP) on their quality characteristics was analyzed. Studies were carried out to examine the supplementation of different percentages of LBP (2%, 4%, 6%, and 8%) on the quality characteristics of LBP muffins. The incorporation of LBP significantly affected the physicochemical parameters of muffins. Such incorporation at different levels significantly decreased pH, moisture content, baking loss, hardness, and color parameters, including L*, a*, and b* values of muffins (p<0.05). No significant effect of LBP substitution was found in height changes (p>0.05). Finally, the consumer acceptance test indicated that the highest levels of LBP incorporation (i.e., 8%) had a considerably adverse effect on consumer preferences in all attributes. In contrast, muffins with moderate levels of LBP (4%) showed a good and satisfactory sensorial acceptance in general. Thus, LBP was successfully employed in muffins, improving quality and broadening its potential applications in other bakery products.
        4,000원
        7.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The domestic catch of squid is decreasing every year. Import volume is increasing to replace these domestic products. Import volume is expected to increase in the future, so it is necessary to study import substitution. Therefore, in this study, after selecting frozen squid, which accounts for the majority of imported squid, as the target fish species, China, Chile and Peru, which account for the majority of frozen squid imports, will be selected as the target countries for analysis. Then, the demand function of squid is estimated using the Rotterdam model, the inverse Rotterdam model, AIDS and inverse AIDS, which are the simultaneous equation demand types, and then elasticity is derived. After that, these models are compared in terms of significance, theoretical fit and practical fit.
        5,200원
        8.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present paper, the natural fiber materials that can be replaced to reduce the weight of the vehicle are analyzed by bubble charts of - and - , and the possibility of alternative application of materials is investigated. For this purpose, the driving energy and fuel efficiency of the vehicle using the data of K model analyzed. In addition, the effect of vehicle weight on fuel efficiency was analyzed through the dynamic analysis approach of the vehicle. From the research results, the following results were obtained. Most of natural fibers have lower density and equal tensile strength and strain than metal materials. Therefore, the application rate of natural fiber materials should be increased in consideration of the application purpose and material characteristics of the vehicle. The major variables that greatly influence driving energy and fuel efficiency were fuel efficiency improvement of about 10% in order of speed, rolling resistance and mass. In addition, when steel is lightened by 10%, fuel efficiency improvement of up to maximum 4.5% is shown in the order of CFRP, Al, Ti.
        4,000원
        9.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the physicochemical properties and acceptability of yellow layer cake prepared using various levels of wet-milled rice flour (RF). RF was used to substitute 0% (control group), 15% (RF-15 group), 30% (RF-30 group) and 45% (RF-45 group) of wheat flour (WF) to manufacture yellow layer cakes. The substitution of WF with RF showed no significant effect on the pH but decreased the specific gravity and viscosity of the batter. Baking loss rates ranged from 4.65% to 5.03%, showing no significant difference among samples. In the color measurement, the experimental groups showed higher redness (a) and yellowness (b) than the control group (p<0.05). The experimental groups showed lower gumminess and chewiness than the control group. According to the results of intensity measurement of sensory properties, the RF-30 and RF-45 groups showed stronger intensities for darkness, sweetness, moistness and softness than the control group. The acceptance test found that the RF-45 group had significantly higher or similar results for all acceptance attributes than the control group. These results indicate that RF addition as a replacement of WF at a ratio of 45% is optimal for producing yellow layer cakes.
        4,000원
        10.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문의 목적은 토니 모리슨의 『재즈』에서 일어나는 의문의 살인사건을 통해서 한 사람의 죽음과 그 의미를 규명하는 것이다. 이를 위해 에마뉘엘 레비나스의 ‘대속’의 개념을 원용하여 소설에서 묘사된 죽음을 ‘타자’를 위한 ‘대속적 죽음’으로 정의한다. 살인사건의 가해자는 중년의 남자 조 트레이스이고, 피해자는 그의 애인인 열여덟 살 소녀 도카스이다. 도카스는 조에게 흔적만 남은 어머니의 ‘대체물’이며 어머니를 향한 욕망의 대상이다. 도카스 또한 ‘내면의 공허’를 채우기 위해 유부남 조와 성적인 일탈을 감행한다. 그러나 그녀는 삶의 마지막 순간, 그를 위해서 스스로 죽음을 선택한다. 그녀는 그가 쏜 총에 맞고도 그가 도망갈 수 있도록 그의 정체를 밝히지 않는다. 도카스의 죽음은 ‘자신보다 다른 어떤 것,’ ‘자신 밖에 있는 어떤 것’을 더 사랑한 결과로서, 바로 타자의 잘못을 제 죽음을 무릅쓰고라도 책임지는 죽음이다. 도카스가 조에게 유언으로 남긴 ‘하나뿐인 사과’는 그녀 자신을 가리키는 것으로, 그녀는 ‘대속적 죽음’을 통하여 ‘대체물’이 아니라 독특하고 유일한 존재, 즉 ‘대체 불가능한 자’가 된다. 결론적으로, 『재즈』가 형상화하는 ‘대속적 죽음’은 타자를 위한 책임과 대속이라는 철학적 요구에 대한 하나의 문학적 응답으로 읽을 수 있다.
        5,800원
        11.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : In this study, an ASR-reducing (alkali-silica reaction) cement was developed to prevent the blow-up of concrete pavements. To develop ASR-reducing cement, various amounts of ground granulated blast furnace slag (GGBFS), and fly ash (FA) were substituted with Portland cement, and the ASR reduction effect was verified through various experiments. METHODS : The physical properties of ASR-reducing cement, varying with the substitution amounts of GGBFS and FA, were verified through compressive strength tests. In addition, the ASR reduction effect was examined using accelerated mortar bar tests. Furthermore, the reasons for the ASR reduction were investigated using microstructural analysis techniques, such as XRD and TG/DTG. RESULTS : There was a difference in the compressive strength results according to the amount of GGBFS and FA substitution. In addition, the samples with GGBFS and FA exhibited relatively lower compressive strengths at 3 days, than OPC samples, but the compressive strength at 28 days was higher than that of the OPC samples. The samples with GGBFS and FA had higher compressive strength at 28 days than OPC samples, because the substituted GGBFS and FA induced pozzolanic reaction. Through XRD and TG/DTG analyses, various degrees of pozzolanic reaction occurring in the samples were examined, and a more active pozzolanic reaction occurred in the samples with FA than in the samples with GGBFS. Therefore, it appeared that the ASR reduction effect occurred because of the induced pozzolanic reaction. CONCLUSIONS : GGBFS and FA substituting Portland cement indicated an ASR reduction effect, which was owing to the pozzolanic reaction. In addition, FA indicated a greater ASR reduction effect than GGBFS, which suggested that FA induced a more active pozzolanic reaction than GGBFS.
        4,000원
        12.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the semantic map model is adopted to study the diachronic evolution and synchronic regional characteristics of the Chinese Verbs “Dai (代)” and “Ti (替)” with the meaning of “substitution”. The semantic evolution of the Verbs “Dai (代)” and “Ti (替)” are complicated, including the evolution in both dialects and general language, which can be clearly shown in the semantic map model. In the general language, “Dai (代)” and “Ti” have different lexical semantic functions. “Dai” mainly has the verbs semantic functions of “substitution”, yet the newer word “Ti (替)” mainly has the grammatical function of “substitution”. In the dialect, the evolution of the two verbs in different regions are not consistent. In northern dialects, the newer word “Ti (替)” is mostly used, yet in some southern dialects, more components of the ancient Chinese are retained, such as the prepositional function of “Dai (代)” in ancient Chinese.
        7,000원
        13.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        철근콘크리트 기둥에서 후프철근의 내진갈고리 시공성을 개선하기 위하여 기존 연구에서 “띠철근 갈고리 뽑힘 방지 장치”인 RCC장치(Rebar Confinement Clip)를 제안하여 인발실험을 통한 부착 및 정착성능 실험을 실시하였다. 그러나, 기존 연구의 실험에서는 콘크리트 구조기준에서 제시하는 피복두께를 준수하지 않았다. 그러므로, 보다 신뢰성 있는 실험 결과를 도출하 기 위하여 기준에서 제시하는 피복두께를 준수한 실험체로 실험을 실시할 필요가 있다. 이를 위하여 총 6개 실험체를 제작하여 실험을 실시하였으며 실험결과, 부착 및 정착의 합성강도는 RCC장치로 체결된 띠철근의 갈고리가 내진갈고리가 발휘하는 강도 보다 높게 나타났다. 또한, 내진갈고리의 실험체 균열 진전 및 파괴 양상과 RCC장치로 체결된 띠철근의 실험체는 유사하게 나타났다. 그러므로, 콘크리트 피복두께를 준수한 실험체에서 RCC장치로 띠철근에 체결할 경우 내진갈고리가 발휘하는 동등한 성능을 보유하고 있는 것으로 평가된다.
        4,300원
        14.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 생각/생각회피 과제를 이용하여 의도적 생각회피, 즉 생각억제와 생각대체의 효과를 종합적으로 검증하였다. 이를 위해 연관성이 높지 않은 2음절 단어자극을 선정하고, 단일집단을 대상으로 회상조건(단서회상, 표적회상)과 훈련조건(생각, 생각억제, 생각대체, 기저선)의 정확회상률을 비교하였다. 그 결과, 훈련조건과 관계없이 표적 회상에 비해 단서회상의 정확기억률이 높은 것으로 나타났으며, 회상조건과 관계없이 다른 조건에 비해 생각조건의 정확회상률이 높은 것으로 나타났다. 또한 회상조건과 훈련조건의 상호작용 효과의 경향성이 나타났으며, 세부적 검증 결과. 생각억제의 경우, 회상조건 간 차이가 나타나지 않은 반면에 생각대체의 경우에는 표적회상에 비해 단서회상의 정확기억률이 높은 것으로 나타났다. 이러한 결과는 생각억제와 생각대체전략이 모두 의도적으로 생각을 회피 하는데 효과적이라는 것과 더불어 생각억제와 생각대체전략이 서로 다른 원리에 의해 발생할 수 있음을 시사한다.
        4,000원
        15.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the substitution effect of phosphate and isolated soybean powder (ISP) by Allomyrina dichotoma larvae powder (AP) in emulsion sausage. The sausages were prepared for five treatments: 1) positive control (PC): sausages manufactured with sodium pyrophosphate (0.3%) and ISP (1%); 2) negative control (NC): sausages manufactured without sodium pyrophosphate, and ISP; 3) phosphate replacement (PR): sausages manufactured with ISP and AP (1%); 4) ISP replacement (IR): sausages manufactured with sodium pyrophosphate and AP; 5) phosphate and ISP replacement (PIR): sausages manufactured with AP. The 1% AP extract showed DPPH radical scavenging (45.65±2.468%) and metal chelating (22.46±3.559%) activity. The high pH value of AP (8.03) increased the pH of the meat batter of PR, IR, and PIR (p<0.05), but there was no inhibitory effect on cooking loss. Cooking loss of IR was not significantly different with PC due to phosphate. The addition of AP decreased the L* and a* values and increased the b* values, and decreased hardness, chewiness, and springiness of PR, IR, and PIR (p<0.05). AP did not inhibit lipid oxidation in sausages, in contrast to phosphate. In sensory evaluation, the addition of AP resulted in low scores for all sensory parameters of the sausages, although most panels had normal or positive awareness (p<0.05). Aroma was more influential on samples than color. Overall, AP did not replace phosphate and ISP in the sausages. Therefore, processes such as eliminating unique aroma and color and increasing solubility through particle size control are necessary to use AP as a protein source.
        4,200원
        17.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The co-doping effect of aliovalent metal ions such as Mg2+, Ca2+, Sr2+, Ba2+, and Zn2+ on the photoluminescence of the Y2O3:Eu3+ red phosphor, prepared by spray pyrolysis, is analyzed. Mg2+ metal doping is found to be helpful for enhancing the luminescence of Y2O3:Eu3+. When comparing the luminescence intensity at the optimum doping level of each Mg2+ ion, the emission enhancement shows the order of Zn2+ Ba2+ > Ca2+ > Sr3+> Mg2+. The highest emission occurs when doping approximately 1.3% Zn2+, which is approximately 127% of the luminescence intensity of pure Y2O3:Eu3+. The highest emission was about 127% of the luminescence intensity of pure Y2O3:Eu3+ when doping about 1.3% Zn2+. It is determined that the reason (Y, M)2O3:Eu3+ has improved luminescence compared to that of Y2O3:Eu3+ is because the crystallinity of the matrix is improved and the non-luminous defects are reduced, even though local lattice strain is formed by the doping of aliovalent metal. Further improvement of the luminescence is achieved while reducing the particle size by using Li2CO3 as a flux with organic additives.
        4,000원
        18.
        2019.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Lu(Nb,Ta)O4:Eu3+ powders are synthesized by a solid-state reaction process using LiCl and Li2SO4 fluxes. The photoluminescence (PL) excitation spectra of the synthesized powders consist of broad bands at approximately 270 nm and sharp peaks in the near ultraviolet region, which are assigned to the Nb5+-O2− charge transfer of [NbO4]3− niobates and the f-f transition of Eu3+, respectively. The PL emission spectra exhibit red peaks assigned to the 5D0 → 7FJ transitions of Eu3+. The strongest peak is obtained at 614 nm (5D0 → 7F2), indicating that the Eu3+ ions are incorporated into the Lu3+ asymmetric sites. The addition of fluxes causes the increase in emission intensity, and Li2SO4 flux is more effective for enhancement in emission intensity than is LiCl flux. The substitution of Ta5+ for Nb5+ results in an increase or decrease in the emission intensity of LuNb1-xTaxO4:Eu3+ powders, depending on amount and kind of flux. The findings are explained using particle morphology, modification of the [NbO4]3− structure, formation of substructure of LuTaO4, and change in the crystal field surrounding the Eu3+ ions.
        4,000원
        19.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        There are lots of duplicative components in the glyph blocks of Maya hieroglyphs. Some of them are used to double the meaning or sound value of the original components. Some of them are just the aesthetic consideration of scribal which does not affect the significance of the original components. This phenomenon, which was discovered by earlier Maya epigraphers, still needs researches on its causes and substitution patterns. This essay discussed these two issues based on the rearrangement of the glyph blocks containing duplicative components. From the perspective of graphic structure, the doubling phenomenon existed in both syllabic signs and glyphs. There are two reasons for the doubling phenomenon as such. The redundancy and simplification of signs lead to the sign-internal duplication. The unique spelling rule of Mayan language lead to the repetition of the syllabic signs. From the perspective of glyphs, the doubling phenomenon existed in both compound graphs and couplets which are caused by the recombination of glyphs. The substitution patterns of these phenomenon are the use of doubling signs, underspelling, choosing different variants of the same syllabic sign, and sharing components. All of these four substitution patterns can function both in the glyph-internal and between different glyphs.
        5,500원
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