• 한국재료학회지
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• 제32권3호
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• pp.125-131
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• 2022

Effect of sulfation processes on the physicochemical properties of ZrO₂ and TiO₂ nanoparticles were thoroughly investigated. SO₄/ZrO₂ and SO₄/TiO₂ catalysts were synthesized to identify the acidity character of each. The wet impregnation method of ZrO₂ and TiO₂ nanoparticles was employed using H2SO₄ with various concentrations of 0.5, 0.75, and 1 M, followed by calcination at 400, 500, and 600 ℃ to obtain optimum conditions of the catalyst synthesis process. The highest total acidity was found when using 1 M SO₄/ZrO₂-500 and 1 M SO₄/TiO₂-500 catalysts, with total acidity values of 2.642 and 6.920 mmol/g, respectively. Sulfation increases titania particles via agglomeration. In contrast, sulfation did not practically change the size of zirconia particles. The sulfation process causes color of both catalyst particles to brighten due to the presence of sulfate. There was a decrease in surface area and pore volume of catalysts after sulfation; the materials' mesoporous structural properties were confirmed. The 1 M SO₄/ZrO₂ and 1 M SO₄/TiO₂ catalysts calcined at 500 ℃ are the best candidate heterogeneous acid catalysts synthesized in thus work.

• Animal Bioscience
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• 제36권10호
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• pp.1604-1611
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• 2023

Objective: The aim of this study was to investigate the protective effect of wheat phytase as a structural decomposer of inflammatory nucleotides, extracellular adenosine triphosphate (ATP), and uridine diphosphate (UDP) on HT-29 cells. Methods: Phosphatase activities of wheat phytase against ATP and UDP was investigated in the presence or absence of inhibitors such as L-phenylalanine and L-homoarginine using a Pi Color Lock gold phosphate detection kit. Viability of HT-29 cells exposed to intact- or dephosphorylated-nucleotides was analyzed with an EZ-CYTOX kit. Secretion levels of pro-inflammatory cytokines (IL-6 and IL-8) in HT-29 cells exposed to substrate treated with or without wheat phytase were measured with enzyme-linked immunosorbent assay kits. Activation of caspase-3 in HT-29 cells treated with intact ATP or dephosphorylated-ATP was investigated using a colorimetric assay kit. Results: Wheat phytase dephosphorylated both nucleotides, ATP and UDP, in a dose-dependent manner. Regardless of the presence or absence of enzyme inhibitors (L-phenylalanine and L-homoarginine), wheat phytase dephosphorylated UDP. Only L-phenylalanine inhibited the dephosphorylation of ATP by wheat phytase. However, the level of inhibition was less than 10%. Wheat phytase significantly enhanced the viability of HT-29 cells against ATP- and UDP-induced cytotoxicity. Interleukin (IL)-8 released from HT-29 cells with nucleotides dephosphorylated by wheat phytase was higher than that released from HT-29 cells with intact nucleotides. Moreover, the release of IL-6 was strongly induced from HT-29 cells with UDP dephosphorylated by wheat phytase. HT-29 cells with ATP degraded by wheat phytase showed significantly (13%) lower activity of caspase-3 than HT-29 cells with intact ATP. Conclusion: Wheat phytase can be a candidate for veterinary medicine to prevent cell death in animals. In this context, wheat phytase beyond its nutritional aspects might be a novel and promising tool for promoting growth and function of intestinal epithelial cells under luminal ATP and UDP surge in the gut.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.390-390
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• 2013

Use of recycled aggregates in portland cement concrete construction can offer benefits associated with both economy and sustainability. Testing performed to date indicates that RBMA can be used as a 100% replacement for conventional coarse aggregate in concrete that exhibits acceptable mechanical properties for use in structural and pavement elements, including satisfactory performance in some durability tests. RBMAC is currently not used in any type of construction in the United States. However, use of RBMAC could become a viable construction strategy as sustainable building practices become the norm. Rating systems such as LEED offer points for reuse of building materials (particularly on-site) and use of recycled materials. If renovations at an existing facility call for the demolition of existing brick masonry constructions, the rubble could be included as RBMA in new concrete pavement, sidewalks, or curb and gutter. Other potential uses for RBMAC could include those in the precast concrete industry, particularly in architectural precast concrete applications. In addition to providing acceptable strength and economy, the color of RBMA could be an attractive component of architectural precast concrete panels or other façade components. This paper explores the feasibility of use of RBMAC in several types of sustainable construction initiatives, based upon the findings of previous work with RBMAC produced from construction and demolition waste from a case study site. Guidance for obtaining and using RBMA is presented, along with a summary of material properties of RBMAC that will be useful to construction professionals.

• 한국축산식품학회지
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• 제44권4호
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• pp.779-789
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• 2024

The effects of irradiation on meat constituents including water, proteins, and lipids are multifaceted. Irradiation leads to the decomposition of water molecules, resulting in the formation of free radicals that can have both positive and negative effects on meat quality and storage. Although irradiation reduces the number of microorganisms and extends the shelf life of meat by damaging microbial DNA and cell membranes, it can also accelerate the oxidation of lipids and proteins, particularly sulfur-containing amino acids and unsaturated fatty acids. With regard to proteins, irradiation affects both myofibrillar and sarcoplasmic proteins. Myofibrillar proteins, such as actin and myosin, can undergo depolymerization and fragmentation, thereby altering protein solubility and structure. Sarcoplasmic proteins, including myoglobin, undergo structural changes that can alter meat color. Collagen, which is crucial for meat toughness, can undergo an increase in solubility owing to irradiation-induced degradation. The lipid content and composition are also influenced by irradiation, with unsaturated fatty acids being particularly vulnerable to oxidation. This process can lead to changes in the lipid quality and the production of off-odors. However, the effects of irradiation on lipid oxidation may vary depending on factors such as irradiation dose and packaging method. In summary, while irradiation can have beneficial effects, such as microbial reduction and shelf-life extension, it can also lead to changes in meat properties that need to be carefully managed to maintain quality and consumer acceptability.

• 한국농촌건축학회논문집
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• 제26권3호
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• pp.29-36
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• 2024

The purpose of this study is to define the characteristics of regional architecture shown in the landscape paintings of Paul Cézanne, who is called the father of modern art, and then to think over the form of regional house in Korea modern architecture. The subject of the study focuses on landscape paintings depicting landscapes among Paul Cézanne's post-impressionist works. The research contents are, first, to understand the landscape structural and cubical characteristics of primary psyche-scene landscapes in his thoughts and insight, and second, to understand the characteristics of regional architecture depicted in his landscape paintings. In this study, characteristics of color in his pictures were excluded, and I attempted to find the origins of pure cube, then tried to pull out the cubical from from Korean regional architecture. The research results are summarized as follows. First, more than 54.7% of Paul Cézanne's paintings are post-impressionism, and the fact that he chose landscapes as the subject of his paintings can be explained to show the value of primary psycho-scene. Second, the building depicted in Paul Cézanne's painting is a pure cube as bastide and mas that are local houses in the Aix-en-Provence region in southern France. Third, Korean cubical flat style of house in the village comes from De Stijl that was provided the concept of Cubism and Mondrian's neo-plasticism.

• Structural Monitoring and Maintenance
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• 제11권3호
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• pp.247-262
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• 2024

Domestic sewage can greatly affect the macro-micro physical-mechanical properties of building foundation soils. In order to investigate the effect of domestic sewage on physical and mechanical properties of soils, the physicochemical properties of three groups of different concentrations of domestic sewage contaminated soil were tested through indoor experiments. Combined with scanning electron microscopy, X-ray diffraction experiments, and grey relational analysis, the degree of influence of different concentrations of domestic sewage on the physicochemical properties of soil was compared and analyzed from multiple perspectives such as microstructure and mineral composition, revealing the influencing mechanism of soil pollution by domestic sewage. The results showed that under the immersion of contaminated water, the color of the soaking water turned black first and then yellow, and brownish yellow secretions appeared on the surface of the soil samples. The moisture content, specific gravity, density, and pore ratio index of the soil samples immersed in 50% and 100% domestic sewage decreased with the increase of sewage concentration, while the liquid limit of the soil samples changed in the opposite direction. The immersion time had little effect on the slope of the compression curve of the soil samples soaked in tap water. For the soil samples immersed in domestic sewage, the slope of the compression curve and the compression coefficient increased with the increase of domestic sewage concentration and immersion time, while the compression modulus showed the opposite trend. In the soil samples immersed in tap water, there were a large number of small particles and cementitious substances, and the structure was relatively dense. With the increase of domestic sewage concentration, the microstructure of the soil changed significantly, with the appearance of sigle particle structure, loose and disorderly arrangement of particles, increased and enlarged pores, gradual reduction of small particle substances and cementitious substances, and the soil structure transformed from compact to loose. The research findings can provide theoretical reference for contaminated geotechnical engineering.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.174-175
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• 2012

(In, Ga) N-based III-nitride semiconductor materials have been viewed as the most promising materials for the applications of blue and green light emitting devices such as light-emitting diodes (LEDs) and laser diodes. Although the InGaN alloy can have wide range of visible wavelength by changing the In composition, it is very hard to grow high quality epilayers of In-rich InGaN because of the thermal instability as well as the large lattice and thermal mismatches. In order to avoid phase separation of InGaN, various kinds of structures of InGaN have been studied. If high-quality In-rich InGaN/GaN multiple quantum well (MQW) structures are available, it is expected to achieve highly efficient phosphor-free white LEDs. In this study, we proposed a novel InGaN double hetero-structure grown on GaN nano-pyramids to generate broad-band red-color emission with high quantum efficiency. In this work, we systematically studied the optical properties of the InGaN pyramid structures. The nano-sized hexagonal pyramid structures were grown on the n-type GaN template by metalorganic chemical vapor deposition. SiNx mask was formed on the n-type GaN template with uniformly patterned circle pattern by laser holography. GaN pyramid structures were selectively grown on the opening area of mask by lateral over-growth followed by growth of InGaN/GaN double hetero-structure. The bird's eye-view scanning electron microscope (SEM) image shows that uniform hexagonal pyramid structures are well arranged. We showed that the pyramid structures have high crystal quality and the thickness of InGaN is varied along the height of pyramids via transmission electron microscope. Because the InGaN/GaN double hetero-structure was grown on the nano-pyramid GaN and on the planar GaN, simultaneously, we investigated the comparative study of the optical properties. Photoluminescence (PL) spectra of nano-pyramid sample and planar sample measured at 10 K. Although the growth condition were exactly the same for two samples, the nano-pyramid sample have much lower energy emission centered at 615 nm, compared to 438 nm for planar sample. Moreover, nano-pyramid sample shows broad-band spectrum, which is originate from structural properties of nano-pyramid structure. To study thermal activation energy and potential fluctuation, we measured PL with changing temperature from 10 K to 300 K. We also measured PL with changing the excitation power from 48 ${\mu}W$ to 48 mW. We can discriminate the origin of the broad-band spectra from the defect-related yellow luminescence of GaN by carrying out PL excitation experiments. The nano-pyramid structure provided highly efficient broad-band red-color emission for the future applications of phosphor-free white LEDs.

• 한국조경학회지
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• 제49권2호
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• pp.61-73
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• 2021

본 연구는 사용자의 경험에 의해 생성된 SNS 데이터를 활용하여 이용자의 경관 인식과 경관 특성을 파악하고자 하였다. 이에 섬에서 나타나는 주요 장소와 경관은 어떻게 인지하고 있는지, 주요 경관 특성은 무엇인지 온라인상의 텍스트 데이터와 사진 데이터를 활용하여 분석하였다. 텍스트 데이터는 텍스트마이닝과 네트워크 구조분석을 시행하였으며, 사진 데이터는 경관파악모델과 색채분석을 실시하였다. 연구의 결과는 첫째, 박지·반월도 주제어의 빈도분석 결과, 지역 경관 대상 키워드인 '퍼플교', '두리마을'과 장소, 행태, 경관 이미지 키워드를 도출할 수 있었으며, 이 중 경관 이미지는 감성분석을 동시해 수행함으로써 긍정의 키워드와 함께 도출하여 경관 대상 및 인식을 파악할 수 있었다. 둘째, 네트워크 구조 분석 결과, 주요 키워드와 도출되지 않은 키워드간의 연결을 보다 구체적으로 분석할 수 있어 색채를 활용한 경관 조성이 지역 활성화에 영향을 미치고 있음을 알 수 있었다. 셋째, 경관파악모델을 활용하여 분석한 결과, 주대상인 '퍼플교', '두리마을'을 활용한 선호 경관을 조성하기 위해선 인공요소가 배제되고, 원경으로 대상장인 바다와 하늘이 보이는 조망점을 설정하는 것이 효과적일 것으로 파악되었다. 넷째, 박지·반월도는 색채를 테마로 하여 조성한 최초의 섬으로 인공시설물에 사용된 색채는 주변 환경과 유사한 색채 계열, 상반되는 명도, 채도 값으로 주변 환경과 조화를 이루고 있음을 알 수 있었다. 본 연구는 경관분야에서 방문객이 직접 업로드한 온라인 데이터를 활용하여 이용자의 인식과 경관 대상을 파악하였다. 또한, 텍스트 및 사진 데이터를 모두 활용하여 경관 인식 및 특성을 파악한 것은 어떤 경관과 자원을 선호하고 인지하고 있는지 구체적으로 파악할 수 있다는 점에서 큰 의의가 있다. 또한, 지역의 경관에 대해 방문객의 인식을 파악함에 있어 정량적인 빅데이터 분석 방법과 정성적인 경관파악모델을 활용함은 대규모 이용자의 인식을 파악하고, 결과를 바탕으로 이루어지는 논의를 통해 경관을 보다 구체적으로 이해할 수 있을 것이다.

• 헤리티지:역사와 과학
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• 제40권
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• pp.243-270
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• 2007

직물에 표현되는 연주문은 제작 과정상 크기나 모양의 제약이 없어 그 표현이 자유롭고, 그 형태와 재료 색체 등을 통해서 당시의 사회문화를 유추할 수 있다. 본 연구의 주제인 동전(東傳) 연주문은 사산조 페르시아에서 출발하여 실크로드를 통해 전래된 것으로 동서문화 교류와 밀접해 있다. 이에 본 연구에서는 연주문이 시작되는 5세기부터 10세기에 해당하는 서 중앙아시아의 벽화 복식, 중국 신강 청해 일대에서 출토된 고대직물 그리고 일본 정창원(正倉院) 소장품의 연주문에 대해 고찰하였다. 그리고 이상의 자료를 통해 연주문의 동서 교류 현상과 구조적 변천과정을 밝히는 데에 목적을 두고 있다. 실크로드를 따라 동전(東傳)하는 연주문의 도안은 지역에 따라 조금씩 차이가 난다. 예를 들러 고대 소그들인들이 주로 활동했던 파미르고원 서쪽에서는 서아시아적인 모티브가 변형된 사슴이나 화식조 등을 주제로 하는 연주문금이 출토되지만, 쿠차 신강에서는 중국적인 모티브가 첨가되어 한자문이 삽입되거나 태양신[Helios] 대신 불상문 보살문으로 나타난다. 이처럼 새로운 문양의 등장은 구조적인 변화를 동반하여 점차 사산조 페르시아의 정형화된 패턴에서 벗어나게 된다. 그리고 그 구조적인 변천과정은 후대 여러 문양의 구성 및 배치방법과 연관이 있다. 연주 환간의 마름모꼴 공간에 안치된 사합초화문 등이 능화문의 형태로 발전되었으며, 10세기 이후 나타나는 기하학적인 골조문양의 유행 단위문양을 상하좌우로 배치하는 탑자문의 전개법이 연주문과 유사하다. 요컨대 연주문은 기술적 진보와 함께 표현 자체에서 세련된 예술적 코드를 읽을 수 있으며, 지역이나 문화를 넘어서는 보편적인 문양으로서 중요한 의미를 지닌다.

• 헤리티지:역사와 과학
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• 제55권2호
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• pp.200-211
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• 2022

청자 투각고리문 의자는 4점 일괄유물로 경기도 개성에서 출토된 것으로 전해진다. 청자 의자는 고려시대 당시 청자 제작기술의 우수성과 화려한 생활상을 보여주는 등 미술사적으로 가치가 높아 보물로 지정 관리되어 왔다. 그러나 일괄유물 중 1점의 경우 과거 수리 복원된 것으로, 처리 재료의 열화, 처리자의 미숙함 등으로 인해 미적가치가 하락되었고, 구조적으로 불안하여 재처리의 필요성이 제기되었다. 처리 전 보존상태를 조사한 결과, 물리적 손상은 전반적으로 제조상 결함부위를 중심으로 인위적 손상이 가중되어 구조적으로 취약한 상태를 보였다. 균열부위 및 탈락된 편은 접합면이 맞지 않고 접착제가 청자 표면에 흐른 자국과 접착제 표면에 분진 등 2차적 오염물이 생겨 변질된 상태였다. 수리복원 상태를 조사하기 위해 자외선과 확대현미경을 이용하여 균열부의 접합 부위의 위치와 범위, 상태를 파악하였다. 적외선분광 분석(FT-IR)과 휴대용 X-선 형광분석을 실시하여 보존처리에 사용한 재료를 분석한 결과, 접착제로 셀룰로오스계 수지와 에폭시계 수지가 사용된 것을 확인하였다. 또한 일부 힘을 받는 접합부위에서는 접합강도를 높이기 위해 접착제에 석고(CaSO₄·2H₂O) 또는 골분(Ca₁₀ (PO₄)₆(OH)₂)을 첨가한 것을 알 수 있었다. 상태조사 결과를 바탕으로, 유물의 보존처리는 기존 접합된 상태에서 전면 해체하고 물리적으로 취약한 부분을 중심으로 접합·복원을 통해 보강하는데 중점을 두었다. 기존에 사용된 접착제를 제거하고 해체한 결과, 청자 의자는 크게 상부와 하부, 굽다리, 일부 고리 문 등 총 6개 편으로 분리되었다. 해체 후 접합면에 남아 있는 잔류 접착제 및 오염물은 화학적 및 물리적으로 제거하고 스팀세척기로 파단면 세척을 통해 재접합의 효율을 높였다. 유물의 접합은 접합부위와 크기에 따라 접착제를 다르게 적용하였다. 편의 위치만 고정하는 접합부에는 시아노아크릴계 수지 Loctite^® 401을 사용하고 구조적으로 안정화시키는 부분에는 가역성을 위해 아크릴계 수지인 Paraloid^® B-72 20%(in xylene)로 단면처리한 후 에폭시계 수지 Epo-tek^® 301-2를 이용하여 접합하였다. 상·하부 접합 같이 힘을 받는 부위는 Epo-tek^® 301-2에 Kaolin을 첨가하여 접합강도를 보강하였다. 연속되는 문양으로 추정 가능한 고리문의 결실 부분은 SN-Sheet로 뼈대를 만들고 Wood epos^®로 파손단면을 연결하여 모델링하면서 고리문을 복원하였다. 그 외 접합하면서 생긴 복원 부위는 심미적 및 구조적 안정화를 위해 Wood epos^®로 메움처리하였다. 복원부위 및 메움처리한 부분은 추후 전시활용에 있어 이질감이 없도록 색맞춤하였다. 다양한 과학기술을 활용한 조사와 처리과정은 체계적으로 기록하여 보존 관리하는데 기초자료로 활용하도록 하였다.