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Protein-based soft micro-optics fabricated by femtosecond laser direct writing
Sun, Yun-Lu,Dong, Wen-Fei,Niu, Li-Gang,Jiang, Tong,Liu, Dong-Xu,Zhang, Lu,Wang, Ying-Shuai,Chen, Qi-Dai,Kim, Dong-Pyo,Sun, Hong-Bo Nature Publishing Group 2014 Light, science & applications Vol.3 No.1
<P>In this work, we report a novel soft diffractive micro-optics, called 'microscale kinoform phase-type lens (micro-KPL)', which is fabricated by femtosecond laser direct writing (FsLDW) using bovine serum albumin (BSA) as building blocks and flexible polydimethylsiloxane (PDMS) slices as substrates. By carefully optimizing various process parameters of FsLDW (e. g., average laser power density, scanning step, exposure time on a single point and protein concentration), the as-formed protein micro-KPLs exhibit excellent surface quality, well-defined three-dimensional (3D) geometry and distinctive optical properties, even in relatively harsh operation environments (for instance, in strong acid or base). Laser shaping, imaging and other optical performances can be easily achieved. More importantly, micro-KPLs also have unique flexible and stretchable properties as well as good biocompatibility and biodegradability. Therefore, such protein hydrogel-based micro-optics may have great potential applications, such as in flexible and stretchable photonics and optics, soft integrated optical microsystems and bioimplantable devices.</P>
고강도 후크형 강섬유로 보강된 콘크리트의 압축 및 휨 성능
왕기 ( Qi-wang ),김동휘 ( Dong-hwi Kim ),윤현도 ( Hyun-do Yun ),장석준 ( Seok-joon Jang ),김선우 ( Sun-woo Kim ) 한국구조물진단유지관리공학회 2021 한국구조물진단유지관리공학회 논문집 Vol.25 No.6
이 논문은 고강도 후크형 강섬유 보강량과 형상비에 따른 콘크리트의 압축 및 휨 성능에 미치는 영향에 대하여 다룬다. 이를 위하여 총 10개 콘크리트 배합이 계획되었다. 설계기준강도 30 MPa인 콘크리트에 형상비(l/d)가 64, 67, 80인 강섬유를 0.25%, 0.50%, 0.75% 혼입하여 강섬유 보강콘크리트가 제조되었다. 형상비 64, 67, 80인 강섬유의 인장강도는 각각 2,000, 2,400, 2,100 MPa이다. 시험 결과로부터 고강도 후 크형 강섬유의 혼입량은 콘크리트의 압축 및 휨 성능에 영향을 미치는 것으로 나타났다. 강섬유 혼입량이 증가함에 따라 푸아송비 및 압축인성은 향상되었으나 콘크리트의 압축강도 및 탄성계수에 큰 변화를 보이지 않았다. 강섬유 보강 콘크리트의 균열발생후 휨거동의 특성을 나타내는 잔여 휨강도 및 노치에서 시작된 균열면에서 에너지 소산능력은 강섬유의 혼입률 및 형상비에 따라 크게 좌우되었다. 특히 MC2010에서 정의된 사용 및 극한 상태한계에서의 잔여 휨강도는 강섬유 혼입량과 형상비가 증가함에 따라 증가되었다. This paper investigates the effect of high strength hooked-end steel fiber content and aspect ratio on the compressive and flexural performance of concrete. A total of ten mixtures were prepared and tested. Concretes with specific compressive strength of 30 MPa were reinforced with three different aspect ratios (l/d) of steel fibers 64, 67, and 80 and three different percentages of steel fibers 0.25, 0.50, and 0.75% by volume of concrete. Tensile strengths of steel fibers with l/d of 64, 67, and 80 are 2,000, 2,400, and 2,100 MPa, respectively. The compressive and flexural properties of plain and steel fiber-reinforced concrete (SFRC) mixtures were evaluated and compared. The experimental results indicated that the incorporation of high-strength hooked-end steel fibers had significant effects on the compressive and flexural performance of concrete. With the increase of steel fiber content, compressive performances, such as Poisson's ratio and toughness, of concrete were improved. The steel fibers with the least l/d of 67 resulted in a larger enhancement of compressive performances. The residual flexural strength, that is, post-cracking flexural resistance and toughness, of concrete is mainly depended on the dosage and aspect ratio of steel fibers. The residual flexural strength at serviceability (SLS) and ultimate limit state (ULS) defined in fib Model Code 2010 (MC2010) is increased as the fiber content and aspect ratio increase.
철근콘크리트 연결보의 강섬유 혼입을 통한 구속 철근 대체가능성 평가
김동휘(Kim, Dong Hwi),왕기(Wang, Qi),정우진(Jeong, Woo Jin),지성준(Ji, Sung Jun),윤현도(Yun, Hyun Do) 한국콘크리트학회 2021 한국콘크리트학회 학술대회 논문집 Vol.33 No.2
본 연구는 복잡한 배근상세를 갖는 연결보의 배근상세 완화를 위해 수행되었으며, 강섬유보강 콘크리트의 구속 철근 대체 가능성을 평가하기 위해 실시되었다. 이를 위해 설계 압축강도 24MPa 급의 SFRC 연결보를 제작하였으며, 섬유혼입률은 0.75%로 설정하였다. This study was conducted to alleviate the reinforcement details of a coupling beam with complicated reinforcement details, and to evaluate the possibility of replacing the confining rebar in steel fiber reinforced concrete. For this, an SFRC coupling beam with a design compressive strength of 24 MPa was manufactured, and the fiber volume fraction was set at 0.75%.
강섬유보강 콘크리트 보에 매립된 SHCC 센서의 자기감지 성능
왕기(Wang, Qi),김동휘(Kim, Dong Hwi),정우진(Jeong, Woojin),지성준(Ji, Sungjun),윤현도(Yun, Hyun Do) 한국콘크리트학회 2021 한국콘크리트학회 학술대회 논문집 Vol.33 No.2
본 연구는 MWCNT 3% 혼입된 SHCC(변형 경화형 시멘트 복합체) 센서가 매립된 강섬유 혼입률 5%의 섬유보강 콘크리트 보에 휨 및 자기감지 성능에 미치는 영향을 평가하였다. 실험 결과는 반복 및 단조 하중에 대해 전기저항의 변화가 민감하게 나타났다. The fexural performance and self-sensing capacity of a SHCC (Strain-Hardening Cementitious Composites) sensor combined with 3% MWCNT (Multi-Walled Carbon Nanotube) implanted in fiber reinforced concrete prisms with a mix of 5% steel fiber is explored in this study. The results reveal that under cyclic and single loading situations, the resistance values of cement-based sensors are sensitive.
New Triterpenoids from the Fruits of Schisandra wilsoniana and Their Biological Activities
Gao, Xue-Mei,Li, Yun-Qi,Shu, Li-Dan,Shen, Yan-Qiong,Yang, Li-Ying,Yang, Liu-Meng,Zheng, Yong-Tang,Sun, Han-Dong,Xiao, Wei-Lie,Hu, Qiu-Fen Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.3
Investigation of an organic extract of the fruits Schisandra wilsoniana led to the isolation of two new highly oxygenated nortriterpenoids, named schilancidilactones V-W (1-2). Their structures were elucidated by spectroscopic evidence. Compounds 1-2 feature a double bond between C-7 and C-8 compared with related known nortriterpenoids isolated from the genus Schisandra. Compounds 1 and 2 were tested for their anti-HIV-1 activities and cytotoxicity. The results revealed that compounds 1 and 2 showed moderate anti-HIV-1 activities with $EC_{50}$ 3.05 and 2.87 ${\mu}g/mL$, respectively, and compound 1 showed high cytotoxicity against KB and MDA-MB-231 cell with $IC_{50}$ values of 3.18 and 5.22 ${\mu}M$, respectively.