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Natural Frequencies of Euler-Bernoulli Beam with Open Cracks on Elastic Foundations
Youngjae Shin,Jonghak Yun,Kyeongyoun Seong,Jaeho Kim,Sunghwang Kang 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.4
A study of the natural vibrations of beam resting on elastic foundation with finite number of transverse open cracks is presented. Frequency equations are derived for beams with different end restraints. Euler-Bernoulli beam on Winkler foundation and Euler-Bernoulli beam on Pasternak foundation are investigated. The cracks are modeled by massless substitute spring. The effects of the crack location, size and its number and the foundation constants, on the natural frequencies of the beam, are investigated.
Seon Choi,Jonghak Kim,Yun Jeong Na,Dae Heon Kim 한국당과학회 2022 한국당과학회 학술대회 Vol.2022 No.07
In eukaryotic cells, organellar proteome biogenesis is pivotal for cellular function. Chloroplasts contain a complex proteome, the biogenesis of which includes post-translational import of nuclear-encoded proteins. Protein-targeting machineries must provide chaperones to protect their membrane-protein substrates from aggregation and to keep them in a translocation-competent state. However, the mechanisms determining when and how nascent chloroplast-targeted membrane proteins are sorted and guided in the cytosol are unknown. Here, we establish the timing and mode of interaction between ankyrin repeat-containing protein 2 (AKR2A), the cytosolic targeting factor of chloroplast outer membrane (COM) proteins, and its interacting partners during translation at the single-molecule level. The targeting signal of a nascent AKR2A client protein residing in the ribosomal exit tunnel induces AKR2A binding to ribosomal RPL23A. Subsequently, RPL23A-bound AKR2A binds to the targeting signal when it becomes exposed from ribosomes. AKR2A-mediated targeting of COM proteins is coupled to their translation, which in turn is crucial for biogenesis of the entire chloroplast proteome. On the other hand, structural analysis, molecular modeling, and mutational analysis of the Ankyrin repeat domain (ARD) of AKR2A identified two adjacent sites for coincidental and synergistic binding of monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG), and this and this binding is very important for the membrane insertion or import into the chloroplast of their cargo proteins. Finally, based on the understanding of the targeting mechanism of these membrane proteins, we investigate the possibility of utilizing organelles as oral delivery vehicle for protein therapuetics such as vaccines and protein drugs through engineering of the chloroplast outer membrane and membrane proteins.
Water vapor removal using CA/PEG blending materials coated hollow fiber membrane
Kim, KeeHong,Ingole, Pravin G.,Yun, SangHee,Choi, WonKil,Kim, JongHak,Lee, HyungKeun John WileySons, Ltd 2015 Journal of chemical technology and biotechnology Vol.90 No.6
<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>In this study, a polyethersulfone composite hollow fiber membrane was used for the separation of water vapor from mixed gas. For improvement of the separation properties, the fabricated membrane was coated with cellulose acetate (CA) and polyethylene glycol (PEG).</P><P><B>RESULTS</B></P><P>Experiments on the permeation of water vapor and N<SUB>2</SUB> gas mixture were performed to observe membrane behavior as a function of the coating conditions, such as the composition and molecular weight of PEG. The water vapor permeance and selectivity of water vapor/N<SUB>2</SUB> improved from 68.5 GPU to 444.1 GPU and from 76.1 to 175.5, respectively, using 5 wt% PEG 2000 blended coating solution.</P><P><B>CONCLUSION</B></P><P>An increase in the PEG content and molecular weight of the coating solution affected the permeance and selectivity due to the hydrophilicity of PEG and the structural changes of the coating layer. © 2014 Society of Chemical Industry</P>
신영재(Youngjea Shin),전수주(Suju Jaun),윤종학(Jonghak Yun) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper presented the application of the technique of differential transformation of free vibration of non-homogeneous damped beam. It is concerned with computing the eigenvalues of a continuous beam model with damping. The beam considered has different stiffness, damping and mass properties in each of two parts. The various boundary conditions are assumed at each end. The results obtained by the present method agree very well with those reported in the previous works. The present analysis shows the usefulness and validity of differential transformation in solving a non-homogeneous damped beam problem.
신영재(Youngjae Shin),전수주(Suju Jaun),윤종학(Jonghak Yun) 한국자동차공학회 2005 한국 자동차공학회논문집 Vol.13 No.5
In this paper, the natural frequencies of non-homogeneous damped beam are determined by using the differential transformation. The beam considered has different stiffness, damping and mass properties in each of two parts. The various boundary conditions are assumed at each end. The results obtained by the present method agree very well with those reported in the previous works. The present analysis shows the usefulness and validity of differential transformation in solving a non-homogeneous damped beam problem.