Photo‐Polymerization Induced Hierarchical Pattern via Self‐Wrinkling

2021 ◽  
pp. 2106754
Author(s):  
Xiaxin Gao ◽  
Jin Li ◽  
Tiantian Li ◽  
Zhilong Su ◽  
Xiaodong Ma ◽  
...  
Keyword(s):  
Photo Polymerization ◽  
Hierarchical Pattern

scholarly journals Patterned waveguide liquid crystal displays

RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41693-41702
Author(s):  
Yunho Shin ◽  
Jinghua Jiang ◽  
Guangkui Qin ◽  
Qian Wang ◽  
Ziyuan Zhou ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Switching Time ◽  
Contrast Ratio ◽  
Liquid Crystal Displays ◽  
High Contrast ◽  
High Brightness ◽  
Photo Polymerization ◽  
Ultrafast Switching ◽  
Light Waveguide ◽  
Polymer Stabilized

A polymer stabilized LC based light waveguide display is reported. Performance is improved by patterned photo-polymerization or electrode. It has high brightness, ultrafast switching time, high contrast ratio, and high transmittance for transparent and augmented displays.

scholarly journals Self-Sensitization and Photo-Polymerization of Diacetylene Molecules Self-Assembled on a Hexagonal-Boron Nitride Nanosheet

Polymers ◽  
2018 ◽  
Vol 10 (2) ◽  
pp. 206 ◽  
Author(s):  
Elisseos Verveniotis ◽  
Yuji Okawa ◽  
Kenji Watanabe ◽  
Takashi Taniguchi ◽  
Takaaki Taniguchi ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Photo Polymerization ◽  
Boron Nitride Nanosheet ◽  
Self Assembled

scholarly journals Effect of Photoinitiator on Precursory Stability and Curing Depth of Thiol-Ene Clickable Gelatin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1877
Author(s):  
Kai-Hung Yang ◽  
Gabriella Lindberg ◽  
Bram Soliman ◽  
Khoon Lim ◽  
Tim Woodfield ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Visible Light ◽  
Rheological Properties ◽  
Swelling Ratio ◽  
Sodium Persulfate ◽  
Photo Polymerization ◽  
Gelation Kinetics ◽  
The Stability ◽  
Over Time

Recent advances highlight the potential of photopolymerizable allylated gelatin (GelAGE) as a versatile hydrogel with highly tailorable properties. It is, however, unknown how different photoinitiating system affects the stability, gelation kinetics and curing depth of GelAGE. In this study, sol fraction, mass swelling ratio, mechanical properties, rheological properties, and curing depth were evaluated as a function of time with three photo-initiating systems: Irgacure 2959 (Ig2959; 320–500 nm), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; 320–500 nm), and ruthenium/sodium persulfate (Ru/SPS; 400–500 nm). Results demonstrated that GelAGE precursory solutions mixed with either Ig2959 or LAP remained stable over time while the Ru/SPS system enabled the onset of controllable redox polymerization without irradiation during pre-incubation. Photo-polymerization using the Ru/SPS system was significantly faster (<5 s) compared to both Ig2959 (70 s) and LAP (50 s). Plus, The Ru/SPS system was capable of polymerizing a thick construct (8.88 ± 0.94 mm), while Ig2959 (1.62 ± 0.49 mm) initiated hydrogels displayed poor penetration depth with LAP (7.38 ± 2.13 mm) in between. These results thus support the use of the visible light based Ru/SPS photo-initiator for constructs requiring rapid gelation and a good curing depth while Ig2959 or LAP can be applied for photo-polymerization of GelAGE materials requiring long-term incubation prior to application if UV is not a concern.

Performance and Friction Properties of Injection Hybrid Moulds with Stereolithography Moulding Zones

2006 ◽  
Vol 514-516 ◽  
pp. 1673-1677 ◽  
Author(s):  
Mathias G. Westphal ◽  
António Sergio Pouzada ◽  
Gean V. Salmoria ◽  
Carlos H. Ahrens
Keyword(s):  
Structural Integrity ◽  
Chemical Properties ◽  
Rapid Manufacturing ◽  
Mechanical And Thermal Properties ◽  
Layer By Layer ◽  
Metallic Materials ◽  
Moulding Process ◽  
Photo Polymerization ◽  
Geometric Precision ◽  
And Chemical Properties

Stereolithography is a rapid manufacturing process that builds objects layer-by-layer based on the photo polymerization of a liquid resin. Due to the good geometric precision, this process has been used in Rapid Tooling for injection moulding. These tools are suitable for the production of short runs of parts and prototypes, where without resorting to the manufacture of a conventional metallic mould. The mechanical and thermal properties of the stereolitography resins, used in the manufacture of hybrid moulds, differ substantially from those of the conventional metallic materials. Particularly they must be known for guaranteeing the structural integrity and the thermal performance of the mould. Also the chemistry behaviour of the resin in contact with the polymer is important when tribological aspects are involved, especially during the ejection of the moulding. In this work, the behaviour of hybrid moulds with SL Vantico 5260 resin moulding cores was assessed. Several thermoplastics (iPP, ABS, PET and PA 6.6) were moulded, and their mechanical, thermal and chemical properties considered and related to the performance of the moulding process. Also, the friction properties of the SL resin in contact with the moulded thermoplastic in moulding conditions were observed and considered in the context of the performance of hybrid moulds.

Fabrication of Three-Dimensional Micro-Structures with Two-Photon Absorption by Femtosecond Laser

2006 ◽  
Vol 532-533 ◽  
pp. 568-571
Author(s):  
Ming Zhou ◽  
Hai Feng Yang ◽  
Li Peng Liu ◽  
Lan Cai
Keyword(s):  
Photonic Crystal ◽  
Femtosecond Laser ◽  
Detection System ◽  
Three Dimensional ◽  
Photon Absorption ◽  
Micro Fabrication ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photo Polymerization ◽  
System A

The photo-polymerization induced by Two-Photon Absorption (TPA) is tightly confined in the focus because the efficiency of TPA is proportional to the square of intensity. Three-dimensional (3D) micro-fabrication can be achieved by controlling the movement of the focus. Based on this theory, a system for 3D-micro-fabrication with femtosecond laser is proposed. The system consists of a laser system, a microscope system, a real-time detection system and a 3D-movement system, etc. The precision of micro-machining reaches a level down to 700nm linewidth. The line width was inversely proportional to the fabrication speed, but proportional to laser power and NA. The experiment results were simulated, beam waist of 0.413μm and TPA cross section of 2×10-54cm4s was obtained. While we tried to optimize parameters, we also did some research about its applications. With TPA photo-polymerization by means of our experimental system, 3D photonic crystal of wood-pile structure twelve layers and photonic crystal fiber are manufactured. These results proved that the micro-fabrication system of TPA can not only obtain the resolution down to sub-micron level, but also realize real 3D micro-fabrication.

scholarly journals RHPTree—Risk Hierarchical Pattern Tree for Scalable Long Pattern Mining

2022 ◽  
Vol 16 (4) ◽  
pp. 1-33
Author(s):  
Danlu Liu ◽  
Yu Li ◽  
William Baskett ◽  
Dan Lin ◽  
Chi-Ren Shyu
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Pattern Mining ◽  
Tree Structure ◽  
Research Initiative ◽  
Speed Up ◽  
Dynamic Tree ◽  
Significant Patterns ◽  
Search Approach ◽  
Hierarchical Pattern

Risk patterns are crucial in biomedical research and have served as an important factor in precision health and disease prevention. Despite recent development in parallel and high-performance computing, existing risk pattern mining methods still struggle with problems caused by large-scale datasets, such as redundant candidate generation, inability to discover long significant patterns, and prolonged post pattern filtering. In this article, we propose a novel dynamic tree structure, Risk Hierarchical Pattern Tree (RHPTree), and a top-down search method, RHPSearch, which are capable of efficiently analyzing a large volume of data and overcoming the limitations of previous works. The dynamic nature of the RHPTree avoids costly tree reconstruction for the iterative search process and dataset updates. We also introduce two specialized search methods, the extended target search (RHPSearch-TS) and the parallel search approach (RHPSearch-SD), to further speed up the retrieval of certain items of interest. Experiments on both UCI machine learning datasets and sampled datasets of the Simons Foundation Autism Research Initiative (SFARI)—Simon’s Simplex Collection (SSC) datasets demonstrate that our method is not only faster but also more effective in identifying comprehensive long risk patterns than existing works. Moreover, the proposed new tree structure is generic and applicable to other pattern mining problems.

scholarly journals Integrating layer by layer manufacturing for the realization of polymer complex geometries with scanning devices: re-building by digital data

2021 ◽  
Author(s):  
Carlo Bruni ◽  
Luciano Greco ◽  
Tommaso Mancia ◽  
Massimiliano Pieralisi
Keyword(s):  
Original Data ◽  
Digital Data ◽  
Complex Geometries ◽  
Polymer Complex ◽  
Layer By Layer ◽  
Input File ◽  
3D Scanner ◽  
Photo Polymerization ◽  
Layer Manufacturing ◽  
Computer Aided

The additive manufacturing technique represents a way to realize components or prototypes without the use of conventional tools.The research presented aims at proposing a methodology based on the use of three different techniques that are the poly-jet 3D using UV photo-polymerization, the FDM of polyamide materials and the FDM of PLA materials. The original data were used at the beginning with the first technique in order to detect the shape and the geometry by a 3D SCANNER. The objective was the re-building of a model shape made using a procedure in which the input file characteristics were updated starting from those got by the scanning device in order to respect the original requirements defined in the computer aided environment. It was found that the physical re-building of an object is depending the characteristics of the input file that needs to be digitally processed in order to get the desired shape and geometry. In that way also FDM using PLA and polyamide materials can be utilized to get components or prototypes from scanned digital data. The results are reported in details.

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