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Lee, Seong-Cheol,Bang, Du-Yeol,S. Chonan,H. Inooka 한국정밀공학회 1992 한국정밀공학회지 Vol. No.
This paper provides the end-point positioning of a single-link flexible robot arm by inverse dynamics. The system is composed of a flexible arm, the mobile ballscrew stage as an arm base, a DC servomotor as an actuator, and a computer. Actuator voltages required for the model of a flexible arm to follow a given tip trajectory are formulated on the basis of the Bermoullie-Euler beam theory and solved by applying the Laplace transform method, and computed by the numerical inversion method proposed by Weeks. The mobile stage as the arm base is shifted so that the end-point follows the desired trajectories. Then the trajectory of end-point is measured by the laser displacement sensor. Here, two kinds of functions are chosen for the given tip trajectories. One is what is called the bang-bang acceleration profile and the other is the Gaussian velocity profile.
Block Copolymer Nanolithography: Translation of Molecular Level Control to Nanoscale Patterns
Bang, Joona,Jeong, Unyong,Ryu, Du Yeol,Russell, Thomas P.,Hawker, Craig J. WILEY‐VCH Verlag 2009 Advanced Materials Vol.21 No.47
<P><B>Abstract</B></P><P>The self‐asembly of block copolymers is a promising platform for the “bottom‐up” fabrication of nanostructured materials and devices. This review covers some of the advances made in this field from the laboratory setting to applications where block copolymers are in use.</P>
Size control and registration of nano-structured thin films by cross-linkable units
Kim, Eunhye,Shin, Changhak,Ahn, Hyungju,Ryu, Du Yeol,Bang, Joona,Hawker, Craig J.,Russell, Thomas P. Royal Society of Chemistry 2008 Soft matter Vol.4 No.3
<P>Thermoset thin films <I>via</I> directed self-assembly, where benzocyclobutene (BCB) groups are incorporated selectively into the one block, have been prepared from cross-linkable block copolymers in a simple process, which allows size controllability and the registration of oriented microdomains in multi-layer applications.</P> <P>Graphic Abstract</P><P>Thermoset thin films <I>via</I> directed self-assembly, prepared from cross-linkable block copolymers, allow size controllability and the registration of oriented microdomains in multi-layer applications. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b717903k'> </P>
Optimized Solvent Vapor Annealing for Long-Range Perpendicular Lamellae in PS-<i>b</i>-PMMA Films
Kim, Kyunginn,Park, Sungmin,Kim, Yeongsik,Bang, Joona,Park, Cheolmin,Ryu, Du Yeol American Chemical Society 2016 Macromolecules Vol.49 No.5
<P>We report a simple approach to fabricating highly stable, perpendicularly oriented lamellae through the self-assembly of high-molecular-weight polystyrene-bpoly(methyl methacrylate) (PS-b-PMMA). Using a solvent vapor annealing (SVA) process controlled by modulating the temperature gap between the chamber and bottom plate, followed by a subsequent thermal annealing process, the ordering stability of perpendicularly oriented lamellae was investigated. The temperature gap that regulates the solvent absorption and dewetting times of the swollen block copolymer (BC?) films was adjusted to enable the films to wet a neutral substrate, thereby facilitating ordering and structural development with no ordering failure. An optimized SVA process at a selected temperature gap of 5 degrees C was found to display the excellent long-term stability, at which highly ordered line arrays composed of perpendicularly oriented lamellae were confined to large-width (3.2 mu m) topographic line patterns. This study also provides the effective time window for the SVA process, suggesting a simple and efficient route to fabricating long-range lateral ordering in BCP self-assembled structures.</P>
Choi, Eunyoung,Park, Sungmin,Ahn, Hyungju,Lee, Moongyu,Bang, Joona,Lee, Byeongdu,Ryu, Du Yeol American Chemical Society 2014 Macromolecules Vol.47 No.12
<P>Lamellar microdomain orientation in polystyrene-<I>b</I>-poly(methyl methacrylate) (PS-<I>b</I>-PMMA) films was controlled by a solvent vapor annealing process, where the high-molecular-weight block copolymer (BCP) was used to self-assemble in a large period of 105 nm. A neutral solvent annealing with tetrahydrofuran vapor screened the difference in the surface energy between the two blocks and the interfacial interactions of the substrate with each block, leading to the substrate-independent perpendicular orientation of lamellar microdomains. Together with thermal annealing of the solvent-annealed BCP film, we demonstrate that highly ordered line arrays of perpendicularly oriented lamellae were well guided in topographic line and disk photoresist patterns composed of the PS-attractive cross-linked copolymer, where the interlamellar <I>d</I>-spacing compliant to the patterns was dependent on the confinement types.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2014/mamobx.2014.47.issue-12/ma500716f/production/images/medium/ma-2014-00716f_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma500716f'>ACS Electronic Supporting Info</A></P>
권대규,최병용,임숙정,방두열,이성철 전북대학교 공업기술연구소 2001 工學硏究 Vol.32 No.-
This paper presents the active control of a flexible intelligent beam with added mass. The two types of different materials which are the glass fiber reinforced(GFR) thermoplastic composite and the carbon fabric/epoxy(CFE) theromosetting composite, are employed to achieve vibration characteristics according to added mass induced end of composite beam with a distributed PVDF sensor and piezo-ceramic actuator. The PID controllers are employed to achieve vibration suppression in tranisent vibration situations. Simulations and experiments were carried out with the designed controllers in order to demonstrate the suppression efficiency of each controller.
Jung, Hyunjung,Woo, Sanghoon,Park, Sungmin,Lee, Sumi,Kang, Minhyuk,Choe, Youngson,Son, Jeong Gon,Ryu, Du Yeol,Huh, June,Bang, Joona The Royal Society of Chemistry 2015 SOFT MATTER Vol.11 No.21
<P>The directed self-assembly (DSA) of block copolymers (BCPs) has emerged as an alternative method to replace or complement conventional photolithography as a result of the approximately 10 nm scale of microdomain ordering, the variety of microstructures that can be obtained and its compatibility with current lithographic processes. In DSA, BCP microdomains are controlled <I>via</I> guide patterns and two main techniques are popular: graphoepitaxy and chemoepitaxy assembly. We have demonstrated a simple and feasible technology for a DSA process by combining graphoepitaxy with “inexpensive” chemoepitaxial assembly to improve the alignment of the lamellar microdomains. For chemoepitaxial assembly, the hexagonal surface patterns from cross-linkable, cylinder-forming BCP were used to guide the graphoepitaxial assembly of the overlying BCP lamellar film. When the guiding patterns were prepared on the hexagonal patterns, it was found that the degree of lamellar alignment was significantly improved compared with the lamellar alignment on the homogeneous neutral layers. Simulation results suggested that the underlying hexagonal pattern can assist the lamellar alignment by reducing the large number of orientation states of the lamellar layers. This strategy is applicable to various nanofabrication processes that require a high degree of fidelity in controlling the nanopatterns over large areas with reduced costs.</P> <P>Graphic Abstract</P><P>We demonstrated a simple and feasible technology for a DSA process by combining graphoepitaxy with “inexpensive” chemoepitaxial assembly to improve the alignment of lamellar microdomains. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5sm00250h'> </P>
Kim, Eunhye,Ahn, Hyungju,Park, Sungmin,Lee, Hoyeon,Lee, Moongyu,Lee, Sumi,Kim, Taewoo,Kwak, Eun-Ae,Lee, Jun Han,Lei, Xie,Huh, June,Bang, Joona,Lee, Byeongdu,Ryu, Du Yeol American Chemical Society 2013 ACS NANO Vol.7 No.3
<P>The directed assembly of block copolymer nanostructures with large periods exceeding 100 nm remains challenging because the translational ordering of long-chained block copolymer is hindered by its very low chain mobility. Using a solvent-vapor annealing process with a neutral solvent, which was sequentially combined with a thermal annealing process, we demonstrate the rapid evolution of a perpendicularly oriented lamellar morphology in high molecular weight block copolymer films on neutral substrate. The synergy with the topographically patterned substrate facilitated unidirectionally structural development of ultrahigh molecular weight block copolymer thin filmseven for the structures with a large period of 200 nmleading to perfectly guided, parallel, and highly ordered line-arrays of perpendicularly oriented lamellae in the trenched confinement. This breakthrough strategy, which is applicable to nanolithographic pattern transfer to target substrates, can be a simple and efficient route to satisfy the demand for block copolymer assemblies with larger feature sizes on hundreds of nanometers scale.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-3/nn3051264/production/images/medium/nn-2012-051264_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn3051264'>ACS Electronic Supporting Info</A></P>
Jung, Hyunjung,Hwang, Dongjune,Kim, Eunhye,Kim, Byung-Jae,Lee, Won Bo,Poelma, Justin E.,Kim, Jihyun,Hawker, Craig J.,Huh, June,Ryu, Du Yeol,Bang, Joona American Chemical Society 2011 ACS NANO Vol.5 No.8
<P>Three-dimensional (3D) nanostructures were obtained by the directed formation of multilayer block copolymer (BCP) thin films. The initial step in this strategy involves the assembly and cross-linking of cylinder-forming polystyrene-<I>b</I>-poly(methyl methacrylate) (PS-<I>b</I>-PMMA) BCP, in which 1.5 mol % of reactive azido (−N<SUB>3</SUB>) groups were randomly incorporated along the styrene backbone. Significantly, assembly of thin films of lamellar-forming BCPs on top of the underlying cross-linked cylindrical layer exhibited perpendicular orientations of microdomains between lamellae and cylinder layers. From the theoretical calculation of free energy in the multilayers, it was found that the nematic interactions between polymer chains at the interface play a critical role in the perpendicular orientation of lamellae on the cross-linked cylinder layers. Removal of the PMMA domains then affords nonsymmetrical nanostructures which illustrate the promise of this strategy for the design of well-defined 3D nanotemplates. It was also demonstrated that this structure can be effectively used to enhance the light extraction efficiency of GaN light-emitting diodes. Furthermore, we anticipate that such 3D nanotemplates can be applied to various areas, including advanced BCP nanolithography and responsive surface coating.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-8/nn2006943/production/images/medium/nn-2011-006943_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn2006943'>ACS Electronic Supporting Info</A></P>