Journal articles: 'Periodic Micron Structures'

1

Tran, Tien Duy, Yibo Wang, Alex Glaetzle, Shannon Whitlock, Andrei Sidorov, and Peter Hannaford. "Magnetic Lattices for Ultracold Atoms." Communications in Physics 29, no. 2 (May 14, 2019): 97. http://dx.doi.org/10.15625/0868-3166/29/2/13678.

Full text

Abstract:

This article reviews the development in our laboratory of magnetic lattices comprising periodic arrays of magnetic microtraps created by patterned magnetic films to trap periodic arrays of ultracold atoms. Recent achievements include the realisation of multiple Bose-Einstein condensates in a 10 \(\mu\)m-period one-dimensional magnetic lattice; the fabrication of sub-micron-period square and triangular magnetic lattice structures suitable for quantum tunnelling experiments; the trapping of ultracold atoms in a sub-micron-period triangular magnetic lattice; and a proposal to use long-range interacting Rydberg atoms to achieve spin-spin interactions between sites in a large-spacing magnetic lattice.

APA, Harvard, Vancouver, ISO, and other styles

2

Kar, Soumitra, Swadeshmukul Santra, and Subhadra Chaudhuri. "Direct Synthesis of ZnS Nanoribbons, Micro-Sheets and Tetrapods." Journal of Nanoscience and Nanotechnology 8, no. 6 (June 1, 2008): 3222–27. http://dx.doi.org/10.1166/jnn.2008.150.

Full text

Abstract:

ZnS nano and micro structures such as nanoribbons, large sheets and tetrapod shaped crystals were fabricated by direct thermal evaporation of ZnS powder without using any catalyst. Formation of the one dimensional structures such as nanoribbons and micron order sheets was attributed to the vapor-solid growth mechanism. The formation of octahedron nucleus with cubic crystal structures was proposed as the growth unit of the wurtzite crystal structured tetrapods. Appearance of the periodic stacking faults or twining planes in between alternate cubic and hexagonal crystal structured zones along the growth direction of the ribbons provided secondary growth sites for the octahedron nucleus and subsequent crystal growth resulted in to the formation of the tetrapod arrays. These nano/micro structures of ZnS exhibited a green emission band at room temperature.

APA, Harvard, Vancouver, ISO, and other styles

3

Piccolo, Leonardo, Marco Sorgato, Afif Batal, Stefan Dimov, Giovanni Lucchetta, and Davide Masato. "Functionalization of Plastic Parts by Replication of Variable Pitch Laser-Induced Periodic Surface Structures." Micromachines 11, no. 4 (April 20, 2020): 429. http://dx.doi.org/10.3390/mi11040429.

Full text

Abstract:

Surface functionalization of plastic parts has been studied and developed for several applications. However, demand for the development of reliable and profitable manufacturing strategies is still high. Here we develop and characterize a new process chain for the versatile and cost-effective production of sub-micron textured plastic parts using laser ablation. The study includes the generation of different sub-micron structures on the surface of a mold using femtosecond laser ablation and vario-thermal micro-injection molding. The manufactured parts and their surfaces are characterized in consideration of polymer replication and wetting behavior. The results of the static contact angle measurements show that replicated Laser-Induced Periodic Surface Structures (LIPSSs) always increase the hydrophobicity of plastic parts. A maximum contact angle increase of 20% was found by optimizing the manufacturing thermal boundary conditions. The wetting behavior is linked to the transition from a Wenzel to Cassie–Baxter state, and is crucial in optimizing the injection molding cycle time.

APA, Harvard, Vancouver, ISO, and other styles

4

Wang, Rui, Ying Xu, Xiao Lin Yu, and Yan Min Zhou. "Enhanced Adhesion of Human Osteoblast-Like Cells on Femtosecond Laser Treated Ti-6Al-4V." Advanced Materials Research 739 (August 2013): 101–5. http://dx.doi.org/10.4028/www.scientific.net/amr.739.101.

Full text

Abstract:

Several techniques of implant surface structuring have been used in the past to modify the surface of titanium and its alloys. We first investigated the adhesion property of human osteoblasts (MG-63) on femtosecond laser treated Ti-6Al-4V for application in dental implant. Two different kinds of surface structures were generated with varied laser fluence. (1) Laser-induced periodic surface structures (LIPSS) with a period on the sub-micron level. (2) Microscale peaks and troughs surface structures (MPTSS) with superimposed submicron and nanoscale features. According to the cell quantity and adhesion property of MG-63 on polished and structured samples, femtosecond laser treated Ti-6Al-4V with LIPSS may more suitable for applied in dental implant.

APA, Harvard, Vancouver, ISO, and other styles

5

Berezovska, N., I. Dmitruk, S. Vovdenko, O. Yeshchenko, P. Teselko, A. Dmytruk, and I. Blonskyi. "Sub-micron and nanosized features in laser-induced periodic surface structures." Indian Journal of Physics 93, no. 4 (October 16, 2018): 495–502. http://dx.doi.org/10.1007/s12648-018-1323-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Showman, Adam P., and Timothy E. Dowling. "Nonlinear Simulations of Jupiter's 5-Micron Hot Spots." Science 289, no. 5485 (September 8, 2000): 1737–40. http://dx.doi.org/10.1126/science.289.5485.1737.

Full text

Abstract:

Large-scale nonlinear simulations of Jupiter's 5-micron hot spots produce long-lived coherent structures that cause subsidence in local regions, explaining the low cloudiness and the dryness measured by the Galileo probe inside a hot spot. Like observed hot spots, the simulated coherent structures are equatorially confined, have periodic spacing, propagate west relative to the flow, are generally confined to one hemisphere, and have an anticyclonic gyre on their equatorward side. The southern edge of the simulated hot spots develops vertical shear of up to 70 meters per second in the eastward wind, which can explain the results of the Galileo probe Doppler wind experiment.

APA, Harvard, Vancouver, ISO, and other styles

7

Sendova, Mariana, and Hiroyuki Hiraoka. "Sub-Half-Micron Periodic Structures on Polymer Surfaces with Polarized Laser Irradiation." Japanese Journal of Applied Physics 32, Part 1, No. 12B (December 30, 1993): 6182–84. http://dx.doi.org/10.1143/jjap.32.6182.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Walker, Jean Paul, Venkataraman Swaminathan, Aisha S. Haynes, and Haim Grebel. "Periodic Metallo-Dielectric Structures: Electromagnetic Absorption and its Related Developed Temperatures." Materials 12, no. 13 (June 30, 2019): 2108. http://dx.doi.org/10.3390/ma12132108.

Full text

Abstract:

Multi-layer, metallo-dielectric structures (screens) have long been employed as electromagnetic band filters, either in transmission or in reflection modes. Here we study the radiation energy not transmitted or reflected by these structures (trapped radiation, which is denoted—absorption). The trapped radiation leads to hot surfaces. In these bi-layer screens, the top (front) screen is made of metallic hole-array and the bottom (back) screen is made of metallic disk-array. The gap between them is filled with an array of dielectric spheres. The spheres are embedded in a dielectric host material, which is made of either a heat-insulating (air, polyimide) or heat-conducting (MgO) layer. Electromagnetic intensity trapping of 97% is obtained when a 0.15 micron gap is filled with MgO and Si spheres, which are treated as pure dielectrics (namely, with no added absorption loss). Envisioned applications are anti-fogging surfaces, electromagnetic shields, and energy harvesting structures.

APA, Harvard, Vancouver, ISO, and other styles

9

Yu, Hang, Bing Rui Lu, Hui Li, Jian Ying Li, and Ran Liu. "Fabrication of Nanostructured Hydrophobic Surfaces with Laser Interference Lithography." Advanced Materials Research 815 (October 2013): 457–64. http://dx.doi.org/10.4028/www.scientific.net/amr.815.457.

Full text

Abstract:

The fabrication of large area nanoscale periodic structures on material surfaces for hydrophobicity engineering has been difficult due to the complex processes. Here we propose a two-step fabrication method for periodic nanostructures by combining laser interference lithography (LIL) and reactive ion etching (RIE). Sub-micron periodic nanotip patterns are fabricated in the photoresist by LIL, and then transferred into the silicon substrate using RIE. By measuring the contact angle (CA) of a water droplet on the substrate surface, the wettability of the surface with nanotip structures of various periods is studied. Our experiments show that the nanotip structures fabricated by the combined LIL and RIE process deliver satisfactory hydrophobic tendencies when the periods fall into the submicron scale. When the period of the structure is small enough, the hydrophilicity of the surface can be altered into hydrophobicity. The hydrophobicity achieved by this method is reusable and sustainable with low cost and no composition alteration comparing to chemical methods. The process developed in this work provides potential applications in biosensingand digital fluidics.

APA, Harvard, Vancouver, ISO, and other styles

10

Zheng, H. Y., G. K. L. Ng, Z. L. Li, and X. C. Wang. "Laser surface micro-engineering for industrial applications in Singapore." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 5 (February 12, 2010): 1129–42. http://dx.doi.org/10.1243/09544062jmes1873.

Full text

Abstract:

Some recent research in laser-induced surface ripple structures, surface ablation, surface colouration, and their potential industrial applications are discussed in this article. Both wavelength and sub-wavelength periodic surface structures were observed on semiconductors such as InP and GaN/sapphire surfaces after irradiation of femtosecond laser pulses. The orientation of the periodic structures was dependant on the laser beam polarization, and the period was dependent on the incident laser fluence. Such surface periodic structures may find applications in controlling surface hydrophobic and hydrophilic properties. Excimer laser ablation of epoxy compounds from wafer level chip size packages was found to be a feasible method to expose the micron-size Au bumps for solder reflow, which is a critical process in manufacturing portable electronic products. Studies on controlled surface oxidation by laser pulses showed that a range of colours can be achieved on a stainless steel surface. Selective Cr oxidation and iron oxides were detected. The appearance of colour is the result of the light constructive interference of the transparent oxide layer and is determined by the oxide thickness and the refractive index. The potential industrial applications of the techniques are discussed.

APA, Harvard, Vancouver, ISO, and other styles

11

Hu, Meilin, Jijil JJ Nivas, Martina D’Andrea, Mohammadhassan Valadan, Rosalba Fittipaldi, Mariateresa Lettieri, Antonio Vecchione, Carlo Altucci, and Salvatore Amoruso. "Periodic Surface Structuring of Copper with Spherical and Cylindrical Lenses." Nanomaterials 13, no. 6 (March 10, 2023): 1005. http://dx.doi.org/10.3390/nano13061005.

Full text

Abstract:

The use of a cylindrical lens in femtosecond laser surface structuring is receiving attention to improve the processing efficiency. Here, we investigate the structures produced on a copper target, in air, by exploiting both spherical and cylindrical lenses for beam focusing, aiming at elucidating similarities and differences of the two approaches. The morphological features of the surface structures generated by ≈180 fs laser pulses at 1030 nm over areas of 8 × 8 mm2 were analyzed. For the spherical lens, micron-sized parallel channels are formed on the target surface, which is covered by subwavelength ripples and nanoparticles. Instead, the cylindrical lens leads to a surface decorated with ripples and nanoparticles with a negligible presence of micro-channels. Moreover, the morphological features achieved by focusing ≈180 fs laser pulses at 515 nm with the cylindrical lens and varying the scanning parameters were also studied. The experimental results evidence a direct effect of the hatch distance used in the scanning process on the target surface that contains dark and bright bands corresponding to regions where the rippled surface contains a richer decoration or a negligible redeposition of nanoparticles. Our findings can be of interest in large area surface structuring for the selection of the more appropriate focusing configuration according to the final application of the structured surface.

APA, Harvard, Vancouver, ISO, and other styles

12

Steinbauer, Miloslav, Roman Pernica, Jiri Zukal, Radim Kadlec, Tibor Bachorec, and Pavel Fiala. "MODELING ELECTROMAGNETIC NANOSTRUCTURES AND EXPERIMENTING WITH NANOELECTRIC ELEMENTS TO FORM PERIODIC STRUCTURES." Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska 10, no. 4 (December 20, 2020): 4–14. http://dx.doi.org/10.35784/iapgos.2383.

Full text

Abstract:

We discuss the numerical modeling of electromagnetic, carbon-based periodic structures, including graphene, graphane, graphite, and graphyne. The materials are suitable for sub-micron sensors, electric lines, and other applications, such as those within biomedicine, photonics, nano- and optoelectronics; in addition to these domains and branches, the applicability extends into, for example, microscopic solutions for modern SMART elements. The proposed classic and hybrid numerical models are based on analyzing a periodic structure with a high repeatability, and they exploit the concept of a carbon structure having its fundamental dimension in nanometers. The models can simulate harmonic and transient processes; are capable of evaluating the actual random motion of an electric charge as a source of spurious signals; and consider the parameters of harmonic signal propagation along the structure. The results obtained from the analysis are utilizable for the design of sensing devices based on carbon periodic structures and were employed in experiments with a plasma generator. The aim is to provide a broader overview of specialized nanostructural modeling, or, more concretely, to outline a model utilizable in evaluating the propagation of a signal along a structure’s surface.

APA, Harvard, Vancouver, ISO, and other styles

13

Lee, Hyun, Jong-Won Jeon, Young-Hag Koh, and Hyoun-Ee Kim. "Dual-Scale Porosity Alumina Structures Using Ceramic/Camphene Suspensions Containing Polymer Microspheres." Materials 15, no. 11 (May 29, 2022): 3875. http://dx.doi.org/10.3390/ma15113875.

Full text

Abstract:

This study demonstrates the utility of thermo-regulated phase separable alumina/camphene suspensions containing poly(methyl methacrylate) (PMMA) microspheres as porogens for the production of multi-scale porosity structures. The homogeneous suspension prepared at 60 °C could undergo phase separation during freezing at room temperature. This process resulted in the 3D networks of camphene crystals and alumina walls containing PMMA microspheres. As a consequence, relatively large dendritic pores with several tens of microns size could be created as the replica of frozen camphene crystals. In addition, after the removal of PMMA microspheres via heat-treatment, micron-sized small spherical pores could be generated in alumina walls. As the PMMA content with respect to the alumina content increased from 0 vol% to 40 vol%, while the camphene content in the suspensions was kept constant (70 vol%), the overall porosity increased from 45.7 ± 0.5 vol% to 71.4 ± 0.5 vol%. This increase in porosity is attributed to an increase in the fraction of spherical pores in the alumina walls. Thus, compressive strength decreased from 153 ± 18.3 MPa to 33 ± 7.2 MPa. In addition, multi-scale porosity alumina objects with a honeycomb structure comprising periodic hexagonal macrochannels surrounded by dual-scale porosity walls were constructed using a 3D plotting technique.

APA, Harvard, Vancouver, ISO, and other styles

14

Bazzan, M., N. Argiolas, C. Sada, P. Mazzoldi, S. Grilli, P. Ferraro, P. De Natale, and L. Sansone. "High Resolution X-Ray Characterization of Sub-Micron Periodic Domain Structures in Lithium Niobate Crystals." Ferroelectrics 352, no. 1 (July 10, 2007): 25–34. http://dx.doi.org/10.1080/00150190701354893.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Chen, Kevin, Ebraheem Azhar, Teng Ma, Hanqing Jiang, and Hongbin Yu. "Facile large-area photolithography of periodic sub-micron structures using a self-formed polymer mask." Applied Physics Letters 100, no. 23 (June 4, 2012): 233503. http://dx.doi.org/10.1063/1.4726085.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Hu, Jingyun, Haibin Xue, and Xinping Zhang. "Two-Dimensional Crystalline Gridding Networks of Hybrid Halide Perovskite for Random Lasing." Crystals 11, no. 9 (September 13, 2021): 1114. http://dx.doi.org/10.3390/cryst11091114.

Full text

Abstract:

We report fabrication of large-scale homogeneous crystallization of CH3NH3PbBr3 (MAPbBr3) in the patterned substrate by a two-dimensional (2D) grating. This achieves high-quality optotelectronic structures on local sites in the micron scales and a homogeneous thin-film device in a centimeter scale, proposing a convenient technique to overcome the challenge for producing large-area thin-film devices with high quality by spin-coating. Through matching the concentration of the MAPbBr3/DMF solutions with the periods of the patterning structures, we found an optimized size of the patterning channels for a specified solution concentration (e.g., channel width of 5 μm for a concentration of 0.14 mg/mL). Such a design is also an excellent scheme for random lasing, since the crystalline periodic networks of MAPbBr3 grids are multi-crystalline constructions, and supply strong light-scattering interfaces. Using the random lasing performance, we can also justify the crystallization qualities and reveal the responsible mechanisms. This is important for the design of large-scale optoelectronic devices based on thin-film hybrid halide perovskites.

APA, Harvard, Vancouver, ISO, and other styles

17

Johnson, C. S., N. M. McKenna, and Y. Wang. "Association of microinjected myosin and its subfragments with myofibrils in living muscle cells." Journal of Cell Biology 107, no. 6 (December 1, 1988): 2213–21. http://dx.doi.org/10.1083/jcb.107.6.2213.

Full text

Abstract:

Purified skeletal muscle myosin was labeled with iodoacetamidofluorescein and microinjected into cultured chick myotubes. The fluorescent myosin analogue became incorporated within 10-15 min after injection, into either periodic (mean periodicity = 2.23 +/- 0.02 micron) bands or apparently continuous fibrillar structures. Comparison of rhodamine-labeled alpha-actinin with coinjected fluorescein-labeled myosin suggested that myosin fluorescence was localized at the A-bands of myofibrils. In addition, close examination of the fluorescent myosin bands indicated that they were composed of two fluorescent bars separated by a nonfluorescent line that corresponded to the H-zone. Once incorporated, the myosin underwent a relatively slow exchange along myofibrils as indicated by fluorescence recovery after photobleaching. Glycerinated myofibrils were able to bind fluorescent myosin in a similar pattern in the presence or absence of MgATP, indicating that actin-myosin interactions had little effect on this process. Fluorescent heavy meromyosin did not incorporate into myofibrillar structures after injection. Light meromyosin, however, associated with A-bands as did whole myosin. These results suggest that microinjected myosin, even with its relatively low solubility under the cytoplasmic ionic condition, is capable of association with physiological structures in living muscle cells. Additionally, the light meromyosin portion of the molecule appears to be mainly responsible for the incorporation.

APA, Harvard, Vancouver, ISO, and other styles

18

Lee, Bryan E. J., Hourieh Exir, Arnaud Weck, and Kathryn Grandfield. "Characterization and evaluation of femtosecond laser-induced sub-micron periodic structures generated on titanium to improve osseointegration of implants." Applied Surface Science 441 (May 2018): 1034–42. http://dx.doi.org/10.1016/j.apsusc.2018.02.119.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Wanakule, Nisita S., Alisyn J. Nedoma, Megan L. Robertson, Zhuangxi Fang, Andrew Jackson, Bruce A. Garetz, and Nitash P. Balsara. "Characterization of Micron-Sized Periodic Structures in Multicomponent Polymer Blends by Ultra-Small-Angle Neutron Scattering and Optical Microscopy." Macromolecules 41, no. 2 (January 2008): 471–77. http://dx.doi.org/10.1021/ma701922y.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Diel, Waldemar, Marcel Wassmer, and Klaus Krueger. "Inkjet Printed MgO-Thickfilm-Layer with Embedded BST Pillars." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, CICMT (September 1, 2011): 000255–60. http://dx.doi.org/10.4071/cicmt-2011-tha12.

Full text

Abstract:

Barium strontium titanate (BST) and magnesium oxide (MgO) are common materials for electronic applications. Because of its low permittivity MgO can be used for passivation layers. In contrast to that the high-k BST allows for building up structures with high capacitances. Bandgap and antenna applications are feasible based on periodic BST/MgO structures, which are e.g. woodpile shaped. Furthermore BST can be used for filter or phase shifter applications due to the dielectric constant of BST that can be modified by the applied electrical field. To keep the applied voltage in a low range very fine structures are required. There are reports about the attempt to realize these very fine structures by screen printing or thin film deposition of BST and MgO. In this paper inkjet printing will be presented as an alternative method for the realization of such fine structured thick films. BST particles with a diameter of 0.5 micron are deposited by inkjet printing with the additional advantage of creating two dimensional patterns in one layer. The resulting BST structures are embedded in MgO layers, which are inkjet printed as well. The corresponding, own developed inks are based on an organic non-polar solvent. The particles are dispersed in the solvent by triple-roll-mill process and stabilized sterically. A solvent is found which is compatible to both kinds of particles as well as to the used substrates. Hence, the ink formulation differs only in the solid phase. The printed structures are processed in two steps. First the MgO layer with the included holes is printed, the BST columns are deposited afterwards. The realization of fine MgO and BST structures is demonstrated. Printing of large areas with holes or channels as well as printing of columns with a high aspect ratio is investigated. Numerous designs can be realized using inkjet printing. Any common passive devices as well as periodical structures with small dimensions and high aspect ratio are feasible.

APA, Harvard, Vancouver, ISO, and other styles

21

Rubin, Shimon, Arie Tulchinsky, Amir D. Gat, and Moran Bercovici. "Elastic deformations driven by non-uniform lubrication flows." Journal of Fluid Mechanics 812 (January 5, 2017): 841–65. http://dx.doi.org/10.1017/jfm.2016.830.

Full text

Abstract:

The ability to create dynamic deformations of micron-sized structures is relevant to a wide variety of applications such as adaptable optics, soft robotics and reconfigurable microfluidic devices. In this work, we examine non-uniform lubrication flow as a mechanism to create complex deformation fields in an elastic plate. We consider a Kirchhoff–Love elasticity model for the plate and Hele-Shaw flow in a narrow gap between the plate and a parallel rigid surface. Based on linearization of the Reynolds equation, we obtain a governing equation which relates elastic deformations to gradients in non-homogeneous physical properties of the fluid (e.g. body forces, viscosity and slip velocity). We then focus on a specific case of non-uniform Helmholtz–Smoluchowski electro-osmotic slip velocity, and provide a method for determining the zeta-potential distribution necessary to generate arbitrary static and quasi-static deformations of the elastic plate. Extending the problem to time-dependent solutions, we analyse transient effects on asymptotically static solutions, and finally provide a closed form solution for a Green’s function for time periodic actuations.

APA, Harvard, Vancouver, ISO, and other styles

22

Stomeo, Casolino, Guido, Qualtieri, Scalora, D’Orazio, Vittorio, and Grande. "2D Dielectric Nanoimprinted PMMA Pillars on Metallo-Dielectric Films." Applied Sciences 9, no. 18 (September 11, 2019): 3812. http://dx.doi.org/10.3390/app9183812.

Full text

Abstract:

In this work, we propose an optimized nanoimprint protocol for the fabrication of a two-dimensional (2D) array of polymethyl-methacrylate (PMMA) nano-pillars deposited on different sputtered configurations (bilayer and multi-layer) of copper (Cu) and aluminum nitride (AlN) slabs supported by a silicon dioxide (SiO2) substrate. Both the Cu/AlN bilayer and multilayer thin films were deposited by a sputtering technique. The sub-micron PMMA pillars were realized by using nanoimprint lithography (NIL). In order to optimize the NIL process, several tests were performed by varying temperature and pressure, allowing us to achieve uniform and high-resolution pillars. The fabricated periodic array enabled the phase-matching of the incident plane wave exciting optical resonances. All the fabricated devices were then optically characterized by means of an ad hoc setup, where the reflected light from the sample was analyzed. The fabricated nano-pillars are mechanically stable, and they could be fully exploited for the realization of novel metallo-dielectric core/shell structures for sensing, surface-enhanced Raman spectroscopy, and light–matter interactions.

APA, Harvard, Vancouver, ISO, and other styles

23

Mukhamedgalieva, A. F., A. M. Bondar, I. M. Svedov, M. A. Kononov, V. B. Laptev, and N. N. Novikova. "The investigations of nanoclusters and micron-sized periodic structures created at the surface of the crystal and amorphous silica by resonant CO2laser irradiation." EPJ Web of Conferences 132 (December 13, 2016): 03035. http://dx.doi.org/10.1051/epjconf/201713203035.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Mukhamedgalieva, A. F., A. M. Bondar, I. M. Shvedov, M. A. Kononov, V. B. Laptev, and N. N. Novikova. "The Spectroscopical and Microstructural Investigations of Nanoclusters and Micron-Sized Periodic Structures Created at the Surface of the Crystal and Amorphous Silica by Resonant CO2Laser Irradiation." EPJ Web of Conferences 103 (2015): 06006. http://dx.doi.org/10.1051/epjconf/201510306006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Baronti, Luca, Aleksandra Michalek, Marco Castellani, Pavel Penchev, Tian Long See, and Stefan Dimov. "Artificial neural network tools for predicting the functional response of ultrafast laser textured/structured surfaces." International Journal of Advanced Manufacturing Technology 119, no. 5-6 (January 7, 2022): 3501–16. http://dx.doi.org/10.1007/s00170-021-08589-9.

Full text

Abstract:

AbstractArtificial Neural Networks (ANNs) are well-established knowledge acquisition systems with proven capacity for learning and generalisation. Therefore, ANNs are widely applied to solve engineering problems and are often used in laser-based manufacturing applications. There are different pattern recognition and control problems where ANNs can be effectively applied, and one of them is laser structuring/texturing for surface functionalisation, e.g. in generating Laser-Induced Periodic Surface Structures (LIPSS). They are a particular type of sub-micron structures that are very sensitive to changes in laser processing conditions due to processing disturbances like varying Focal Offset Distance (FOD) and/or Beam Incident Angle (BIA) during the laser processing of 3D surfaces. As a result, the functional response of LIPSS-treated surfaces might be affected, too, and typically needs to be analysed with time-consuming experimental tests. Also, there is a lack of sufficient process monitoring and quality control tools available for LIPSS-treated surfaces that could identify processing patterns and interdependences. These tools are needed to determine whether the LIPSS generation process is in control and consequently whether the surface’s functional performance is still retained. In this research, an ANN-based approach is proposed for predicting the functional response of ultrafast laser structured/textured surfaces. It was demonstrated that the processing disturbances affecting the LIPSS treatments can be classified, and then, the surface response, namely wettability, of processed surfaces can be predicted with a very high accuracy using the developed ANN tools for pre- and post-processing of LIPSS topography data, i.e. their areal surface roughness parameters. A Generative Adversarial Network (GAN) was applied as a pre-processing tool to significantly reduce the number of required experimental data. The number of areal surface roughness parameters needed to fully characterise the functional response of a surface was minimised using a combination of feature selection methods. Based on statistical analysis and evolutionary optimisation, these methods narrowed down the initial set of 21 elements to a group of 10 and 6 elements, according to redundancy and relevance criteria, respectively. The validation of ANN tools, using the salient surface parameters, yielded accuracy close to 85% when applied for identification of processing disturbances, while the wettability was predicted within an r.m.s. error of 11 degrees, equivalent to the static water contact angle (CA) measurement uncertainty.

APA, Harvard, Vancouver, ISO, and other styles

26

Dey, Rajib, Sergey Alexandrov, Peter Owens, Jack Kelly, Sine Phelan, and Martin Leahy. "Skin cancer margin detection using nanosensitive optical coherence tomography and a comparative study with confocal microscopy." Biomedical Optics Express 13, no. 11 (October 7, 2022): 5654. http://dx.doi.org/10.1364/boe.474334.

Full text

Abstract:

Excision biopsy and histology represent the gold standard for morphological investigation of the skin, in particular for cancer diagnostics. Nevertheless, a biopsy may alter the original morphology, usually requires several weeks for results, is non-repeatable on the same site and always requires an iatrogenic trauma. Hence, diagnosis and clinical management of diseases may be substantially improved by new non-invasive imaging techniques. Optical Coherence Tomography (OCT) is a non-invasive depth-resolved optical imaging modality based on low coherence interferometry that enables high-resolution, cross-sectional imaging in biological tissues and it can be used to obtain both structural and functional information. Beyond the resolution limit, it is not possible to detect structural and functional information using conventional OCT. In this paper, we present a recently developed technique, nanosensitive OCT (nsOCT), improved using broadband supercontinuum laser, and demonstrate nanoscale sensitivity to structural changes within ex vivo human skin tissue. The extended spectral bandwidth permitted access to a wider distribution of spatial frequencies and improved the dynamic range of the nsOCT. Firstly, we demonstrate numerical and experimental detection of a few nanometers structural difference using the nsOCT method from single B-scan images of phantoms with sub-micron periodic structures, acting like Bragg gratings, along the depth. Secondly, our study shows that nsOCT can distinguish nanoscale structural changes at the skin cancer margin from the healthy region in en face images at clinically relevant depths. Finally, we compare the nsOCT en face image with a high-resolution confocal microscopy image to confirm the structural differences between the healthy and lesional/cancerous regions, allowing the detection of the skin cancer margin.

APA, Harvard, Vancouver, ISO, and other styles

27

Papineau, Dominic, Jiayu Yin, Kevin G. Devine, Deng Liu, and Zhenbing She. "Chemically Oscillating Reactions during the Diagenetic Formation of Ediacaran Siliceous and Carbonate Botryoids." Minerals 11, no. 10 (September 28, 2021): 1060. http://dx.doi.org/10.3390/min11101060.

Full text

Abstract:

Chemically oscillating reactions are abiotic reactions that produce characteristic, periodic patterns during the oxidation of carboxylic acids. They have been proposed to occur during the early diagenesis of sediments that contain organic matter and to partly explain the patterns of some enigmatic spheroids in malachite, phosphorite, jasper chert, and stromatolitic chert from the rock record. In this work, circularly concentric self-similar patterns are shown to form in new chemically oscillating reaction experiments with variable mixtures of carboxylic acids and colloidal silica. This is carried out to best simulate in vitro the diagenetic formation of botryoidal quartz and carbonate in two Ediacaran-age geological formations deposited after the Marinoan–Nantuo snowball Earth event in South China. Experiments performed with alkaline colloidal silica (pH of 12) show that this compound directly participates in pattern formation, whereas those with humic acid particles did not. These experiments are particularly noteworthy since they show that pattern formation is not inhibited by strong pH gradients, since the classical Belousov–Zhabotinsky reaction occurs in solution with a pH around 2. Our documentation of hundreds of classical Belousov–Zhabotinsky experiments yields a number of self-similar patterns akin to those in concretionary structures after the Marinoan–Nantuo snowball Earth event. Morphological, compositional, and size dimensional comparisons are thus established between patterns from these experiments and in botryoidal quartz and carbonate from the Doushantuo and Denying formations. Selected specimens exhibit circularly concentric layers and disseminations of organic matter in quartz and carbonate, which also occurs in association with sub-micron-size pyrite and sub-millimetre iron oxides within these patterns. X-ray absorption near edge structure (XANES) analyses of organic matter extracted from dolomite concretions in slightly younger, early Cambrian Niutitang Formation reveal the presence of carboxylic and N-bearing molecular functional groups. Such mineral assemblages, patterns, and compositions collectively suggest that diagenetic redox reactions take place during the abiotic decay of biomass, and that they involve Fe, sulphate, and organic matter, similarly to the pattern-forming experiments. It is concluded that chemically oscillating reactions are at least partly responsible for the formation of diagenetic siliceous spheroids and concretionary carbonate, which can relate to various other persistent problems in Earth and planetary sciences.

APA, Harvard, Vancouver, ISO, and other styles

28

Miyazaki, Koji. "Periodic Micro-structures for Thermal Radiation Control." Hosokawa Powder Technology Foundation ANNUAL REPORT 14 (2006): 122–27. http://dx.doi.org/10.14356/hptf.04117.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Nikiforov, A. I., V. A. Timofeev, V. I. Mashanov, I. D. Loshkarev, I. V. Skvortsov, D. V. Gulyaev, D. D. Firsov, and O. S. Komkov. "Material based on multilayer periodic structures with GeSiSn pseudomorphic layers." «Узбекский физический журнал» 23, no. 3 (December 7, 2021): 1–6. http://dx.doi.org/10.52304/.v23i3.255.

Full text

Abstract:

The growth of multilayer structures with Ge0.3Si0.7-yGey/Si heterojunction at tin content from 0 to 18% was studied. The X-ray diffractometry method shows the presence of strict periodicity of layers and a high level of tin content. It has been established that GeSiSn compounds are thermally stable in the annealing temperature range of 300-550 °C. A photoluminescence signal in the infrared range of about 3 microns is observed from a structure with pseudomorphic GeSiSn layers.

APA, Harvard, Vancouver, ISO, and other styles

30

Sotillo, Belén, Rocio Ariza, Jan Siegel, Javier Solis, and Paloma Fernández. "Preferential Growth of ZnO Micro- and Nanostructure Assemblies on Fs-Laser-Induced Periodic Structures." Nanomaterials 10, no. 4 (April 11, 2020): 731. http://dx.doi.org/10.3390/nano10040731.

Full text

Abstract:

In this work, we demonstrate the use of laser-induced periodic surface structures (LIPSS) as templates for the selective growth of ordered micro- and nanostructures of ZnO. Different types of LIPSS were first produced in Si-(100) substrates including ablative low-frequency spatial (LSF) LIPSS, amorphous-crystalline (a–c) LIPSS, and black silicon structures. These laser-structured substrates were subsequently used for depositing ZnO using the vapor–solid (VS) method in order to analyze the formation of organized ZnO structures. We used scanning electron microscopy and micro-Raman spectroscopy to assess the morphological and structural characteristics of the ZnO micro/nano-assemblies obtained and to identify the characteristics of the laser-structured substrates inducing the preferential deposition of ZnO. The formation of aligned assemblies of micro- and nanocrystals of ZnO was successfully achieved on LSF-LIPSS and a–c LIPSS. These results point toward a feasible route for generating well aligned assemblies of semiconductor micro- and nanostructures of good quality by the VS method on substrates, where the effect of lattice mismatch is reduced by laser-induced local disorder and likely by a small increase of surface roughness.

APA, Harvard, Vancouver, ISO, and other styles

31

Stankevičius, Evaldas, Mindaugas Gedvilas, Bogdan Voisiat, Mangirdas Malinauskas, and Gediminas Račiukaitis. "Fabrication of periodic micro-structures by holographic lithography." Lithuanian Journal of Physics 53, no. 4 (2013): 227–37. http://dx.doi.org/10.3952/physics.v53i4.2765.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

D’Annibale, Francesco, Manuel Ferretti, and Angelo Luongo. "Static and Dynamic Responses of Micro-Structured Beams." Applied Sciences 10, no. 19 (September 29, 2020): 6836. http://dx.doi.org/10.3390/app10196836.

Full text

Abstract:

In this study, we developed a one-dimensional Timoshenko beam model, embedded in a 3D space for static and dynamic analyses of beam-like structures. These are grid cylinders, that is, micro-structured bodies, made of a periodic and specifically designed three-dimensional assembly of beams. Derivation is performed in the framework of the direct 1D approach, while the constitutive law is determined by a homogenization procedure based on an energy equivalence between a cell of the periodic model and a segment of the solid beam. Warping of the cross-section, caused by shear and torsion, is approximatively taken into account by the concept of a shear factor, namely, a corrective factor for the constitutive coefficients of the equivalent beam. The inertial properties of the Timoshenko model are analytically identified under the hypothesis, and the masses are lumped at the joints. Linear static and dynamic responses of some micro-structured beams, taken as case studies, are analyzed, and a comparison between the results given by the Timoshenko model and those obtained by Finite-Element analyses on 3D frames is made. In this framework, the effectiveness of the equivalent model and its limits of applicability are highlighted.

APA, Harvard, Vancouver, ISO, and other styles

33

Ferretti, Manuel, and Francesco D’Annibale. "Buckling of Planar Micro-Structured Beams." Applied Sciences 10, no. 18 (September 18, 2020): 6506. http://dx.doi.org/10.3390/app10186506.

Full text

Abstract:

In this paper, a Timoshenko beam model is formulated for buckling analysis of periodic micro-structured beams, uniformly compressed. These are planar grid beams, whose micro-structure consists of a square lattice of equal fibers, modeled as Timoshenko micro-beams. The equivalent beam model is derived in the framework of a direct one-dimensional approach and its constitutive law, including the effect of prestress of the longitudinal fibers, is deduced through a homogenization approach. Accordingly, micro–macro constitutive relations are obtained through an energy equivalence between a cell of the periodic model and a segment of the equivalent beam. The model also accounts for warping of the micro-structure, via the introduction of elastic and geometric corrective factors of the constitutive coefficients. A survey of the buckling behavior of sample grid beams is presented to validate the effectiveness and limits of the equivalent model. To this purpose, results supplied by the exact analyses of the equivalent beam are compared with those given by finite element models of bi-dimensional frames.

APA, Harvard, Vancouver, ISO, and other styles

34

Härtig, Frank, Michael Paul Krystek, and S. Klein. "Reliable Detection of Periodic Micro Structures on Open Surfaces." Key Engineering Materials 381-382 (June 2008): 15–18. http://dx.doi.org/10.4028/www.scientific.net/kem.381-382.15.

Full text

Abstract:

The reliable determination of periodic micro structures on open surfaces as they exist on involute tooth flanks gain of increasing importance. They allow conclusions from the waviness of the gear surface to the wear and running noise in gears. With the aim of determining traceable wave structures, a method has been developed at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig by which it is possible to model, realise and, especially, reliably evaluate wave-shaped structures on the flank surfaces of involute cylindrical gears.

APA, Harvard, Vancouver, ISO, and other styles

35

Sivakumar, Manickam, and Jun Wang. "Controlled Fabrication of Micro/Nano-Structures on Germanium Using Ultrashort Laser Pulses under Ambient Conditions." Advanced Materials Research 1136 (January 2016): 440–45. http://dx.doi.org/10.4028/www.scientific.net/amr.1136.440.

Full text

Abstract:

A technique for ordered fabrication of periodic freestanding micro/nanostructures on the crystalline germanium (Ge) <100> surfaces with 1064 nm wavelength ultrashort laser pulses under ambient conditions is presented. The laser radiation fluence used for obtaining the structures is close to the melting threshold (0.1 J/cm2) of Ge. The dimensions of structures range from hundreds of nanometres to a few microns. The orientation of the periodic surface structures depends on laser beam polarization direction. Arrays of structures are formed in rows parallel to the sample movement direction for samples machined with s-polarized laser pulses, but formed in the direction perpendicular to the movement for p-polarized pulses. The structures are fabricated under variable temperatures on sample surface owing to the changed interference between incident and reflected laser beams. A micro-Raman analysis of the processed surfaces shows a minor change in the spectral intensity as compared to the unprocessed surface and the material retains its crystallinity after laser irradiation.

APA, Harvard, Vancouver, ISO, and other styles

36

Li, Xin, Yu Cheng Ding, Jin You Shao, and Hong Zhong Liu. "Investigation of Electrohydrodynamic Patterning of Micro Structures at Room Temperature." Applied Mechanics and Materials 367 (August 2013): 3–6. http://dx.doi.org/10.4028/www.scientific.net/amm.367.3.

Full text

Abstract:

EHD (Electrohydrodynamic) patterning forming micro structures with UV light curable materials at room temperature is investigated in this paper. It is a process for fabricating patterns on polymer film by applying electrical field to the template and the substrate as an electrode pair. The maintaining time of EHD patterning is reduced from several hours to tens of minutes by using UV curable polymer with low viscosity. The flat template generates the periodic pillars with micro scale. The periodic pillars with different period are obtained by varying the applied voltage in the different phase of experiment. The micro scale replication with good fidelity is produced by using patterned template made of doped silicon wafer.

APA, Harvard, Vancouver, ISO, and other styles

37

GONG Lei, 巩蕾, 刘阳林 LIU Yanglin, 于洁 YU Jie, 王海斌 WANG Haibin, 王利国 WANG Liguo, 谭林秋 TAN Linqiu, and 吴振森 WU Zhensen. "三维微纳米半球周期结构光学表面场分布及复合散射特性." ACTA PHOTONICA SINICA 50, no. 7 (2021): 173. http://dx.doi.org/10.3788/gzxb20215007.0729001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Lu, Qi, Chang Liu, Ning Wang, Shlomo Magdassi, Daniel Mandler, and Yi Long. "Periodic micro-patterned VO2thermochromic films by mesh printing." Journal of Materials Chemistry C 4, no. 36 (2016): 8385–91. http://dx.doi.org/10.1039/c6tc02694j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Mukhammad, A. I., P. I. Gaiduk, O. Yu Nalivaiko, and V. V. Kolos. "IR TRANSMITTANCE OF Si/SiO2/Si3N4/Si ISLAND STRUCTURES FORMED BY SELECTIVE LASER ANNEALING." Journal of Applied Spectroscopy 89, no. 4 (July 20, 2022): 511–18. http://dx.doi.org/10.47612/0514-7506-2022-89-4-511-518.

Full text

Abstract:

Periodic Si/SiO2/Si3N4/Si structures with an insular surface layer were formed by selective laser annealing. The study by infrared Fourier spectrometry showed a decrease in the transmittance of the island structure formed by selective laser annealing compared to the structure without annealing in range 2–25 microns. It is shown that the decrease in the transmittance value may be due to the presence of highly alloyed regions of recrystallized silicon in the surface layer. Analysis of dispersion curves obtained by FDTD modeling showed that plasma-like oscillations were detected in the range of 5–20 THz, which can support in layers of periodic high-alloyed silicon islands in a layer of unalloyed silicon. The results of the study are interpreted considering the assumption of the occurrence of “spoof” surface plasmons in a structure with an insular surface layer.

APA, Harvard, Vancouver, ISO, and other styles

40

Badin, A. V., A. I. Berdyugin, V. D. Moskalenko, K. V. Simonova, and R. P. Gursky. "Two-dimensional THz reflectometry of a periodic structure obtained by additive technology." Journal of Physics: Conference Series 2140, no. 1 (December 1, 2021): 012015. http://dx.doi.org/10.1088/1742-6596/2140/1/012015.

Full text

Abstract:

Abstract This paper considers the development and application of a system of reflectometry for the analysis of the homogeneity of structures manufactured by additive technologies. A system of reflectometry based on a backward wave oscillator, a two-dimensional object positioning system and an optoacoustic detector (Goley cell) is described. The results of reflectometry of the hexagonal periodic structure of cells based on acrylonitrile butadiene styrene at a wavelength of 343 microns are presented.

APA, Harvard, Vancouver, ISO, and other styles

41

MARTINSSON, P. G., and IVO BABUŠKA. "HOMOGENIZATION OF MATERIALS WITH PERIODIC TRUSS OR FRAME MICRO-STRUCTURES." Mathematical Models and Methods in Applied Sciences 17, no. 05 (May 2007): 805–32. http://dx.doi.org/10.1142/s021820250700211x.

Full text

Abstract:

The equations that govern elastostatic equilibrium between a prescribed force field and an unknown displacement field for materials with periodic skeletal micro-structures are studied. It is shown that as the size of the micro-structure tends to zero, the displacement field will converge to the solution of a constant coefficient partial differential equation. This equation is shown to be either a classical or a micro-polar continuum elasticity equation, depending on the micro-structural geometry and the nature of the external load field. Convergence is proved for representative model problems in Sobolev energy norms and in the maximum norm. In addition, it is shown that by considering pseudo-differential homogenized equations, any order of convergence can be achieved.

APA, Harvard, Vancouver, ISO, and other styles

42

Martinsson, Per-Gunnar, and Ivo Babuška. "Mechanics of Materials with Periodic Truss or Frame Micro-Structures." Archive for Rational Mechanics and Analysis 185, no. 2 (May 12, 2007): 201–34. http://dx.doi.org/10.1007/s00205-006-0044-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Fotsing, Edith Roland, Arnaud Dubourg, Annie Ross, and Jacky Mardjono. "Acoustic properties of periodic micro-structures obtained by additive manufacturing." Applied Acoustics 148 (May 2019): 322–31. http://dx.doi.org/10.1016/j.apacoust.2018.12.030.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Adeniran, B. V., B. D. Bjarkadottir, R. Appeltant, S. Lane, and S. A. Williams. "Improved preservation of ovarian tissue morphology that is compatible with antigen detection using a fixative mixture of formalin and acetic acid." Human Reproduction 36, no. 7 (May 6, 2021): 1871–90. http://dx.doi.org/10.1093/humrep/deab075.

Full text

Abstract:

Abstract STUDY QUESTION Can ovarian tissue morphology be better preserved whilst enabling histological molecular analyses following fixation with a novel fixative, neutral buffered formalin (NBF) with 5% acetic acid (referred to hereafter as Form-Acetic)? SUMMARY ANSWER Fixation with Form-Acetic improved ovarian tissue histology compared to NBF in multiple species while still enabling histological molecular analyses. WHAT IS KNOWN ALREADY NBF fixation results in tissue shrinkage in various tissue types including the ovary. Components of ovarian tissue, notably follicles, are particularly susceptible to NBF-induced morphological alterations and can lead to data misrepresentation. Bouin’s solution (which contains 5% acetic acid) better preserves tissue architecture compared to NBF but is limited for immunohistochemical analyses. STUDY DESIGN, SIZE, DURATION A comparison of routinely used fixatives, NBF and Bouin’s, and a new fixative, Form-Acetic was carried out. Ovarian tissue was used from three different species: human (n = 5 patients), sheep (n = 3; 6 ovaries; 3 animals per condition) and mouse (n = 14 mice; 3 ovaries from 3 different animals per condition). PARTICIPANTS/MATERIALS, SETTING, METHODS Ovarian tissue from humans (aged 13 weeks to 32 years), sheep (reproductively young i.e. 3–6 months) and mice (10 weeks old) were obtained and fixed in 2 ml NBF, Bouin’s or Form-Acetic for 4, 8, and 24 h at room temperature. Tissues were embedded and sectioned. Five-micron sections were stained with haemotoxylin and eosin (H&E) and the percentage of artefact (clear space as a result of shrinkage) between ovarian structures was calculated. Additional histological staining using Periodic acid-Schiff and Masson’s trichrome were performed on 8 and 24 h NBF, Bouin’s and Form-Acetic fixed samples to assess the compatibility of the new fixative with stains. On ovarian tissue fixed for both 8 and 24 h in NBF and Form-Acetic, immunohistochemistry (IHC) studies to detect FOXO3a, FoxL2, collagen IV, laminin and anti-Müllerian hormone (AMH) proteins were performed in addition to the terminal deoxynucleotidyl transferase nick end labelling (TUNEL) assay to determine the compatibility of Form-Acetic fixation with types of histological molecular analyses. MAIN RESULTS AND THE ROLE OF CHANCE Fixation in Form-Acetic improved ovarian tissue morphology compared to NBF from all three species and either slightly improved or was comparable to Bouin’s for human, mouse and sheep tissues. Form-Acetic was compatible with H&E, Periodic acid-Schiff and Masson’s trichrome staining and all proteins (FOXO3a, FoxL2, collagen IV and laminin and AMH) could be detected via IHC. Furthermore, Form-Acetic, unlike NBF, enabled antigen recognition for most of the proteins tested without the need for antigen retrieval. Form-Acetic also enabled the detection of damaged DNA via the TUNEL assay using fluorescence. LARGE SCALE DATA N/A LIMITATIONS, REASONS FOR CAUTION In this study, IHC analysis was performed on a select number of protein types in ovarian tissue thus encouraging further studies to confirm the use of Form-Acetic in enabling the detection of a wider range of protein forms in addition to other tissue types. WIDER IMPLICATIONS OF THE FINDINGS The simplicity in preparation of Form-Acetic and its superior preservative properties whilst enabling forms of histological molecular analyses make it a highly valuable tool for studying ovarian tissue. We, therefore, recommend that Form-Acetic replaces currently used fixatives and encourage others to introduce it into their research workflow. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the Oxford Medical Research Council Doctoral Training Programme (Oxford MRC-DTP) grant awarded to B.D.B. (Grant no. MR/N013468/1), the Fondation Hoffmann supporting R.A. and the Petroleum Technology Development Fund (PTDF) awarded to B.V.A.

APA, Harvard, Vancouver, ISO, and other styles

45

Bălilescu, Loredana, Carlos Conca, Tuhin Ghosh, Jorge San Martín, and Muthusamy Vanninathan. "Bloch wave spectral analysis in the class of generalized Hashin–Shtrikman micro-structures." Mathematical Models and Methods in Applied Sciences 32, no. 03 (February 17, 2022): 497–532. http://dx.doi.org/10.1142/s0218202522500129.

Full text

Abstract:

In this paper, we use spectral methods to introduce Bloch waves for studying the homogenization process in the non-periodic class of generalized Hashin–Shtrikman micro-structures (see Ref. 35), which incorporates both translation and dilation with a family of scales, including one subclass of laminates. We establish the classical homogenization result by providing the spectral representation of the homogenized coefficients. It offers a new lead towards extending the Bloch spectral analysis to general micro-structures, including the class of non-periodic media or the homogenization of Heisenberg operators (see Refs. 8 and 9).

APA, Harvard, Vancouver, ISO, and other styles

46

Xia, Wenxuan, Erkan Oterkus, and Selda Oterkus. "Ordinary state-based peridynamic homogenization of periodic micro-structured materials." Theoretical and Applied Fracture Mechanics 113 (June 2021): 102960. http://dx.doi.org/10.1016/j.tafmec.2021.102960.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Alamri, Sabri, Fotis Fraggelakis, Tim Kunze, Benjamin Krupop, Girolamo Mincuzzi, Rainer Kling, and Andrés Fabián Lasagni. "On the Interplay of DLIP and LIPSS Upon Ultra-Short Laser Pulse Irradiation." Materials 12, no. 7 (March 27, 2019): 1018. http://dx.doi.org/10.3390/ma12071018.

Full text

Abstract:

Controlling laser induced surface morphology is essential for developing specialized functional surfaces. This work presents novel, multi-scale periodic patterns with two-dimensional symmetry generated on stainless steel, polyimide and sapphire. The microstructures were realized by combining Direct Laser Interference Patterning with the generation of Laser Induced Periodic Surface Structures in a one-step process. An industrial, fiber femtosecond laser source emitting at 1030 nm with a pulse duration of 500 fs was utilized for the experiments. In the case of stainless steel, it was possible to create line-like or pillar-like surface patterns by rotating the polarization orientation with respect to the interference pattern. In the case of polyimide and sapphire, the absorption of the laser radiation was promoted by a multiphoton mechanism. In polyimide, grooves and pillars of several microns in depth were produced over an area much larger than the spot size. Finally, for sapphire, the simultaneous generation of interference-like pattern and laser induced periodic surface structures was realized. The results reported here provide valuable data on the feasibility to combine two state-of-the-art techniques with an industrial apparatus, to control the induced surface morphology.

APA, Harvard, Vancouver, ISO, and other styles

48

Dietrich, Felix, and Dennis Merkert. "Homogenization of periodic micro-structures with FFT-based higher order schemes." PAMM 17, no. 1 (December 2017): 583–84. http://dx.doi.org/10.1002/pamm.201710261.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Ma, Yongbin, and Zichen Deng. "A hybrid symplectic and high-frequency homogenization analysis for the dispersion property of periodic micro-structured thin plate structures." Applied Mathematical Modelling 93 (May 2021): 276–93. http://dx.doi.org/10.1016/j.apm.2020.12.017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Fu, Yangxi, Marcos Soldera, Wei Wang, Bogdan Voisiat, and Andrés Fabián Lasagni. "Picosecond Laser Interference Patterning of Periodical Micro-Architectures on Metallic Molds for Hot Embossing." Materials 12, no. 20 (October 18, 2019): 3409. http://dx.doi.org/10.3390/ma12203409.

Full text

Abstract:

In this work, it is demonstrated that direct laser interference patterning (DLIP) is a method capable of producing microtextured metallic molds for hot embossing processes. Three different metals (Cr, Ni, and Cu), relevant for the mold production used in nanoimprinting systems, are patterned by DLIP using a picosecond laser source emitting at a 532 nm wavelength. The results show that the quality and surface topography of the produced hole-like micropatterns are determined by the laser processing parameters, such as irradiated energy density and the number of pulses. Laser-induced periodic surface structures (LIPSS) are also observed on the treated surfaces, whose shapes, periodicities, and orientations are strongly dependent on the accumulated fluence. Finally, the three structured metals are used as embossing molds to imprint microlenses on polymethyl methacrylate (PMMA) foils using an electrohydraulic press. Topographical profiles demonstrate that the obtained structures are comparable to the masters showing a satisfactory reproduction of the texture. The polymeric microlens arrays that showed the best surface homogeneity and overall quality were those embossed with the Cr molds.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Periodic Micron Structures'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles