• 제목/요약/키워드: By-Product Materials

검색결과 2,169건 처리시간 0.032초

Development of High-Temperature Solders: Contribution of Transmission Electron Microscopy

  • Bae, Jee-Hwan;Shin, Keesam;Lee, Joon-Hwan;Kim, Mi-Yang;Yang, Cheol-Woong
    • Applied Microscopy
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    • 제45권2호
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    • pp.89-94
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    • 2015
  • This article briefly reviews the results of recently reported research on high-temperature Pb-free solder alloys and the research trend for characterization of the interfacial reaction layer. To improve the product reliability of high-temperature Pb-free solder alloys, thorough research is necessary not only to enhance the alloy properties but also to characterize and understand the interfacial reaction occurring during and after the bonding process. Transmission electron microscopy analysis is expected to play an important role in the development of high-temperature solders by providing accurate and reliable data with a high spatial resolution and facilitating understanding of the interfacial reaction at the solder joint.

Nonlinear Entropy Production in a Reversible Oregonator Model

  • Basavaraja, C.;Pierson, R.;Park, Seung-Hyun;Jeon, Eun-Ji;Huh, Do-Sung
    • Bulletin of the Korean Chemical Society
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    • 제29권5호
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    • pp.1051-1054
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    • 2008
  • The entropy production in a non-equilibrium state based on the reversible Oregonator model of the Belousov-Zhabotinskii (BZ) reaction system has been studied. The reaction affinity and the reaction rate for the individual steps have been calculated by varying the concentrations of key variables in the system. The result shows a linear relationship between the reaction affinity and the reaction rate in the given concentration range. However, the overall entropy calculated on the basic assumption that the entropy in a reaction system corresponds to the summation of a product of reaction affinity and reaction rate of individual steps shows a nonlinearity of the reaction system. The results well agrees with the fact that the entropy production is not linear or complicated function in a non-linear reaction system.

Silk Fibroin/Chitosan Conjugate Crosslinked by Tyrosinase

  • Kang, Gyung-Don;Lee, Ki-Hoon;Ki, Chang-Seok;Nahm, Joong-Hee;Park, Young-Hwan
    • Macromolecular Research
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    • 제12권5호
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    • pp.534-539
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    • 2004
  • Two biopolymers, silk fibroin (SF) and chitosan, were conjugated by tyrosinase (EC 1.14.18.1), a polyphenolic oxidase, to improve their physicochemical properties, such as their thermal properties and morphological stabilities in organic solvents. The crosslinking between SF and chitosan took place mainly through Michael addition reactions. A main reaction between the amino groups in chitosan and o-quinone, the oxidation product of the tyrosyl residue in SF, was confirmed by UV spectroscopy. Measurements of viscosity and light scattering indicated that the crosslinked SF/chitosan conjugate was compact: it had a smaller particle size because of tight bonding forces between the SF and chitosan molecular chains. Thermal decomposition of SF/chitosan conjugates crosslinked by tyrosinase occurred at higher temperatures. The adhesiveness of the SF/chitosan conjugates decreased steadily as the crosslinking reaction progressed. We propose that this new crosslinking method be used for the preparation of silk fibroin/chitosan conjugates using tyrosinase. We expect that SF/chitosan conjugates crosslinked by tyrosinase can be used preferentially in biomedical applications because of its unique properties and non-toxicity.

PLM 관점의 지속가능패션 신제품 개발에 대한 연구 (Applying PLM Approach for Sustainable New Product Development in Fashion Industry)

  • 전은하;한정하;고은주
    • 한국의류산업학회지
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    • 제20권1호
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    • pp.34-49
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    • 2018
  • Sustainability in fashion pertains to all stages within the product lifecycle, starting with the procurement of raw materials and ending with the disposal of the product. To clarify, the Lifecycle Management (LCM) views the Triple Bottom Line (TBL) from the perspective of a product's lifecycle. Sustainable products are identified based on their lifecycle, causing public attention to turn towards Product Lifecycle Management (PLM). As of now, PLM is largely known to have a strong impact on New Product Development (NPD). As such, the objective of this research is to study how PLM-based sustainable NPD models, when applied to the fashion industry, can produce a wide understanding of sustainable fashion products from a variety of angles. In order to achieve the research objective, this study did a selective case study on 20 sustainable fashion brands; conducted 1:1 in-depth interviews with 24 fashion experts, including both sustainable and non-sustainable experts; and took part in participant observation of 5 sustainable fashion brands. The results of the study indicate that there are specific conditions that must be met at each stage of production for the development of sustainable products by fashion brands. However, due to the lack of technological skills and the dearth of sustainability experts within the organization, management, monitoring and systematic collection of data is not properly implemented - leading to problems with the quantification of crucial data. This study aims to further forward the debate regarding the development of sustainable fashion products and its future implications.

The Dynamics of Noise and Vibration Engineering Vibrant as ever, for years to come

  • Leuridan, Jan
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2010년도 춘계학술대회 논문집
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    • pp.47-47
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    • 2010
  • Over the past 20 years, constant progress in noise and vibration (NVH) engineering has enabled to constantly advance quality and comfort of operation and use of really any products - from automobiles to aircraft, to all kinds of industrial vehicles and machines - to the extend that for many products, supreme NVH performance has becomes part of its brand image in the market. At the same time, the product innovation agenda in the automotive, aircraft and really many other industries, has been extended very much in recent years by meeting ever more strict environmental regulations. Like in the automotive industry, the drive towards meeting emission and CO2 targets leads to very much accelerated adoption of new powertrain concepts (downsizing of ICE, hybrid-electrical...), and to new vehicle architectures and the application of new materials to reduce weight, which bring new challenges for not only maintaining but further improving NVH performance. This drives for innovation in NVH engineering, so as to succeed in meeting a product brand performance for NVH, while as the same time satisfying eco-constraints. Product innovation has also become increasingly dependent on the adoption of electronics and software, which drives for new solutions for NVH engineering that can be applied for NVH performance optimization of mechatronic products. Finally, relentless pressure to shorten time to market while maintaining overall product quality and reliability, mandates that the practice and solutions for NVH engineering can be optimally applied in all phases of product development. The presentation will first review the afore trends for product and process innovation, and discuss the challenges they represent for NVH engineering. Next, the presentation discusses new solutions for NVH engineering of products, so as to meet target brand values, while at the same time meeting ever more strict eco constraints, and this within a context of increasing adoption of electronics and controls to drive product innovation. NVH being very much defined by system level performance, these solutions implement the approach of "Model Based System Engineering" to increase the impact of system level analysis for NVH in all phases of product development: - At the Concept Phase, to be able to do business case analysis of new product concepts; to arrive at an optimized and robust product architecture (e.g. to hybrid powertrain lay-out, to optimize fuel economy); to enable target cascading, to subsystem and component level. - In Development Phase, to increase realism and productivity of simulation, so as to frontload virtual validation of components and subsystems and to further reduce reliance on physical testing. - During the final System Testing Phase, to enable subsystem testing by a combination of physical testing and simulation: using simulation models to simulate the final integration context when testing a subsystem, enabling to frontload subsystem testing before final system integration is possible. - To interconnect Mechanical, Electronical and Controls engineering, in all phases of development, by supporting model driven controls engineering (MIL, SIL, HIL). Finally, the presentation reviews examples of how LMS is implementing such new applications for NVH engineering with lead customers in Europe, Asia and US, with demonstrated benefits both in terms of shortening development cycles, and/or enabling a simulation based approach to reduce reliance on physical testing.

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UVB유도성 CCD-986sk cell에서의 Casuarictin의 항노화 효과 (Anti-aging effects of casuarictin on UVB-induced CCD-986sk cell)

  • 김유아;김동희;김영아;유재묘;박병준;손준호
    • Journal of Applied Biological Chemistry
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    • 제60권1호
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    • pp.13-17
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    • 2017
  • 본 연구는 새로운 기능성 화장품 소재 개발을 위해 복분자 씨앗의 구성성분인 casuarictin을 이용하여 섬유아세포내에서의 항노화 효과를 확인 하고자 하였다. Casuarictin의 항노화 효과를 CCD-986sk 세포를 이용하여 측정한 결과, casuarictin은 UVB에 의해 증가된 ROS 발현을 억제하였으며, pro-collagen의 발현을 증가시키고 MMP-1의 발현을 억제하는 것으로 나타났다. 이는 노화 인자인 활성산소종의 생성 억제와 주름과 밀접한 관련이 있는 콜라겐의 합성 및 분해억제를 통해 항산화 및 주름개선 효과가 있는 것으로 판단되며, 따라서 casuarictin은 화장품 분야에서 항노화 소재로서의 활용가치가 있을 것으로 사료된다.

실내공기질 공정시험방법과 기준의 동시 개정에 따른 접착제 제품의 TVOC 관리수준 평가 (The TVOC management level evaluation of adhesive product following to simultaneous revision of indoor air quality testing methods and standards)

  • 유지호;박준만;김만구
    • 분석과학
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    • 제23권3호
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    • pp.255-260
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    • 2010
  • 환경부에서는 오염물질 다량 방출 건축자재의 효율적인 관리를 위해 "다중이용시설 등의 실내 공기질 관리법" 중 접착제의 시험방법과 방출관리기준을 동시에 개정하였다. 따라서 기존 관리수준과 개정 관리수준의 직접적인 비교가 불가능하다. 이 연구에서는 접착제의 개정된 시험방법의 각 요소들이 오염물질 방출강도에 미치는 영향들을 기존 시험방법과 비교하여 검토하였다. 이를 통하여 개정된 오염물질 방출관리기준을 평가하였다. 그 결과 접착제는 시험기간의 변경으로 인해 방출강도가 약 2.5배 약화되었고 건조시간의 변경에 따른 방출강도의 차이는 거의 없는 것으로 나타났다. 시험방법의 변경된 내용을 적용한 TVOC 방출 관리기준은 기존 방출 관리기준에 비해 약 2.1배 강화된 것으로 나타났다.

廢自動車 ASR의 風力 및 比中選別에 의한 處理 硏究 (Treatment of ASR from End-of-Life Vehicles by Air and Gravimetric Separation)

  • 이화영;오종기
    • 자원리싸이클링
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    • 제14권2호
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    • pp.3-9
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    • 2005
  • 폐자동차 ASR으로부터 염소성분을 제거하기 위하여 풍력선별 및 비중선별 실험을 수행하였다. 또한, ASR플라스틱만을 분리하여 물을 매체로 한 비중선별을 실시하였다. ASR 시료는 모두 8 mm이하로 재분쇄하여 선별실험에 사용하였으며, 플라스틱은 3가지 입도로 나누어 비중선별 실험을 하였다. 풍력선별은 공기유량 9~20 M$^3$/hr 범위의 1단계와 공기유량 25~34 M$^3$/hr 범위의 2단계로 나누어 실시하고 각 산물의 비율과 재질분포를 조사하였다. 1단계 풍력선별후 underflow 산물의 비율은 62~66%인 것으로 나타났으며, 공기유량이 큰 2단계 풍력선별에서는 overflow 산물의 비율이 크게 증가하였다. 폐플라스틱만을 대상으로 한 비중선별 실험결과 부유물질이 침강물질에 비해 다소 많게 나타났으며, 염소함량에 있어서는 최대 수백개의 염소함량 차이를 보여 순수 플라스틱의 경우 매우 우수한 염소함유 재질의 분리효과를 얻을 수 있었다.

산화철계 형석대체제의 전로 정련특성 (BOF Refining of Fluorspar Substitute Using Iron Oxide Based By-product)

  • 금창훈;허보영
    • 한국재료학회지
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    • 제16권5호
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    • pp.336-340
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    • 2006
  • Fluorspar has been essential flux in steelmaking process. The main effects of fluorspar addition are lowering of the viscosity and melting temperature of slag. In recent years, due to the increasing price and environmental problem of fluorspar, various types of fluorspar substitute have been investigated. In this study, iron oxide by-products such as sinter dust, basic oxygen furnace (BOF) sludge and mill scale were developed as a substitute in terms of waste recycling. Several plant trials were carried out by addition of briquetted substitutes of $4{\sim}6$ kg/ton to compare with the fluorspar of $0.7{\sim}1$ kg/ton. The substitutes showed a similar behavior of slag formation, phosphorus removal and MgO saturation content.

분할형 탄소복합재 자전거 프레임 개발에 관한 연구 (A Study on the Development of the Split-Type Carbon Composite Bicycle Frames)

  • 박찬곤;최영;강봉용;김은규
    • 한국정밀공학회지
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    • 제34권2호
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    • pp.139-143
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    • 2017
  • Finite element analysis was performed for a split-type CFRP bicycle frame, which was designed to apply a compression molding process with carbon fiber prepreg for a conventional bicycle. An epoxy adhesive material for joining the frames was selected by the extent of stress at joint interfaces. The split-type bicycle frame was then formed and its weak parts examined by the boundary conditions according to reliability tests. The results verified the reliability of the bicycle frame after modification of these weak parts. The finished product was manufactured by using this developed split-type bicycle frame.