| 1. |
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| 2. |
- Andersen, A., et al.
(author)
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Oscillating Bubble SHG on Surface Elastic and Surface Viscoelastic Systems : New Insights in the Dynamics of Adsorption Layers
- 2006
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 110:37, s. 18466-18472
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Journal article (peer-reviewed)abstract
- Surface rheology governs a great variety of interfacial phenomena such as foams or emulsions and plays a dominant role in several technological processes such as high-speed coating. Its major difference with bulk rheology resides in the high compressibility of the surface phase, which is the direct consequence of the molecular exchange between adsorbed and dissolved species. In analogy to bulk rheology, a complex surface dilational modulus, ε, which captures surface tension changes upon defined area changes of the surface layer, can be defined. The module ε is complex, and the molecular interpretation of the dissipative process that gives rise to the imaginary part of the module is subject to some controversy. In this contribution, we used the oscillating bubble technique to study the surface dilational modulus in the mid-frequency range. The dynamic state of the surface layer was monitored by a pressure sensor and by surface second-harmonic generation (SHG). The pressure sensor measures the real and imaginary part of the modulus while SHG monitors independently the surface composition under dynamic conditions. The experiment allows the assessment of the contribution of the compositional term to the surface dilational modulus ε. Two aqueous surfactant solutions have been characterized: a surface elastic and a surface viscoelastic solution. The elastic surface layer can be described within the framework of the extended Lucassen−van den Tempel Hansen model. The change in surface concentration is in phase with the relative area change of the surface layer, which is in strong contrast with the results obtained from the surface viscoelastic solution. Here, surface tension, area change, and surface composition are phase-shifted, providing evidence for a nonequilibrium state within the surface phase. The data are used to assess existing surface rheology models.
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| 3. |
- Andersson, Henrik, et al.
(author)
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Evaluation of coatings applied to flexible substrates to enhance quality of ink jet printed silver nano-particle structures
- 2012
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In: IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part C. - 1083-4400 .- 1558-1241. ; 2:2, s. 342-348
-
Journal article (peer-reviewed)abstract
- Different types of the commercial surface treatment InkAid have been evaluated as a surface treatment to enhance print quality of silver nano-particle ink structures printed on polyimide and polyethene substrate. Originally these coatings have been specified to be applied on substrates for graphical ink jet printing. On the coated polyimide and polyethene substrates lines of different widths have been printed using a Dimatix materials printer together with silver nano-particle ink manufactured by Advanced Nano Products. The prints have then been evaluated in terms of print quality and resistivity before and after sintering. The results show that the application of these coatings can improve the print quality considerably, making it possible to print lines with a good definition, which is not otherwise possible with this type of ink on this substrate types. It has been found that the coating Semi Gloss provides the best results, both in terms of print quality as well as the lowest resistivity. The resistivity on polyethene is 3.5*10-7Ωm at best when sintered at 150°C and for polyimide 8.9*10-8Ωm sintered at 200°C. This corresponds to a conductivity of about 4.5% and 18%of bulk silver, respectively. It can be concluded that applying such PVP based coatings to polyethene and polyimide will increase the print quality quite substantially, making it possible to print patterns with requirements of smaller line widths and more details than what is possible without coating.
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| 4. |
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| 5. |
- Andersson, Henrik, et al.
(author)
-
The influence of paper coating content on room temperature sintering of silver nanoparticle ink
- 2013
-
In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 24:45, s. Art. no. 455203-
-
Journal article (peer-reviewed)abstract
- The resistance of inkjet printed lines using a silver nanoparticle based ink can be very dependent on the substrate. A very large difference in resistivity was observed for tracks printed on paper substrates with aluminum oxide based coatings compared to silica based coatings. Silica based coatings are often cationized with polymers using chloride as a counter ion. It is suggested that the precipitation of silver salts is the cause of the high resistivity, since papers pretreated with salt solutions containing ions that precipitate silver salts gave a high resistance. Silver nitrate has a high solubility and paper pretreated with nitrate ions gave a low resistivity without sintering. The results obtained show that, by choosing the correct type of paper substrate, it is possible to manufacture printed structures, such as interconnects on paper, without the need for, or at least to reduce the need for, post-print sintering. This phenomenon is, of course, ink specific. Inks without or with a low silver ion content are not expected to behave in this manner. In some sensor applications, a high resistivity is desired and, by using the correct combination of ink and paper, these types of sensors can be facilitated.
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| 6. |
- Andersson, Henrik, Dr, 1975-, et al.
(author)
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Variable low-density polylactic acid and microsphere composite material for additive manufacturing
- 2021
-
In: Additive Manufacturing. - : Elsevier BV. - 2214-8604 .- 2214-7810. ; 40
-
Journal article (peer-reviewed)abstract
- Thermally expandable microspheres are extensively used in industry as a lightweight filler for many products. The spheres can expand up to 60 times the initial size and are used for different purposes, including material reduction and surface modification. In fused filament fabrication (FFF), a material is deposited in a layer-by-layer process. Typically, FFF objects need not be solid because such objects are typically used for applications with low mechanical stress. Low material infill percentages are commonly used inside a solid outer shell to reduce material usage, weight, and manufacturing time. This paper proposes a new composite filament for FFF consisting of polylactic acid (PLA) and thermally expandable Expancel microspheres in the form of masterbatch granules. These filaments contain unexpanded microspheres that can be expanded during printing by heating. Two types of filaments containing 2 wt% and 5 wt% of masterbatch granules were manufactured and tested. The filaments were successfully used with a commercial 3D printer to manufacture objects with a density of 45% compared to objects manufactured using standard PLA. The tensile strength of these objects changed linearly with density and was comparable to that of PLA objects of the same density prepared using infill patterns. The composite filaments are advantageous in that they can reduce the amount of material used, as is currently done by using different amounts of infill in a pattern. Further, by varying the nozzle temperature, their density can be adjusted directly during printing as well as during fabrication to produce layers of different densities in the same object.
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| 7. |
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| 8. |
- Andres, Britta, 1986-
(author)
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Low-Cost, Environmentally Friendly Electric Double-Layer Capacitors : Concept, Materials and Production
- 2017
-
Doctoral thesis (other academic/artistic)abstract
- Today’s society is currently performing an exit from fossilfuel energy sources. The change to sustainable alternativesrequires inexpensive and environmentally friendly energy storagedevices. However, most current devices contain expensive,rare or toxic materials. These materials must be replaced bylow-cost, abundant, nontoxic components.In this thesis, I suggest the production of paper-based electricdouble-layer capacitors (EDLCs) to meet the demand oflow-cost energy storage devices that provide high power density.To fulfill the requirements of sustainable and environmentallyfriendly devices, production of EDLCs that consist of paper,graphite and saltwater is proposed. Paper can be used as aseparator between the electrodes and as a substrate for theelectrodes. Graphite is suited for use as an active material in theelectrodes, and saltwater can be employed as an electrolyte.Westudied and developed different methods for the productionof nanographite and graphene from graphite. Composites containingthese materials and similar advanced carbon materialshave been tested as electrode materials in EDLCs. I suggest theuse of cellulose nanofibers (CNFs) or microfibrillated cellulose(MFC) as a binder in the electrodes. In addition to improvedmechanical stability, the nanocellulose improved the stabilityof graphite dispersions and the electrical performance of theelectrodes. The influence of the cellulose quality on the electricalproperties of the electrodes and EDLCs was investigated.The results showed that the finest nanocellulose quality is notthe best choice for EDLC electrodes; MFC is recommended forthis application instead. The results also demonstrated thatthe capacitance of EDLCs can be increased if the electrodemasses are adjusted according to the size of the electrolyte ions.Moreover, we investigated the issue of high contact resistancesat the interface between porous carbon electrodes and metalcurrent collectors. To reduce the contact resistance, graphitefoil can be used as a current collector instead of metal foils.Using the suggested low-cost materials, production methodsand conceptual improvements, it is possible to reduce the material costs by more than 90% in comparison with commercialunits. This confirms that paper-based EDLCs are apromising alternative to conventional EDLCs. Our findings andadditional research can be expected to substantially supportthe design and commercialization of sustainable EDLCs andother green energy technologies.
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| 9. |
- Arshadi Rastabi, Shahrzad, et al.
(author)
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Metallurgical investigation of aluminum anode behavior in water-in-salt electrolyte for aqueous aluminum batteries
- 2022
-
In: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 523
-
Journal article (peer-reviewed)abstract
- Although ionic liquid electrolytes (ILs) are environmentally unfriendly, they are the most common electrolyte used in aluminum-ion batteries (AIB). Aqueous electrolytes offer a more sustainable alternative, but problem with oxide passivating barrier on Al surface becomes more profound. Recently, a new sub-class of aqueous electrolytes, water-in-salt (WIS) of (AlCl3·6H2O), has been considered, but experimental validation of the behavior of the Al electrode over cycling is required. This work investigates aluminum/graphitic cells using WIS electrolytes with a mass ratio of salt to water of 4, 8, and 12 and finds that they show similar trends in cycling performance. The degradation observed over cycling has been attributed to the formation of a detrimental solid electrolyte interphase (SEI) layer on the Al surface. It was found that WIS 4 increased Al corrosion, resulting in a slightly higher capacity and longer cycling life. Metallurgical observation showed that the Al matrix has a tendency to initiate corrosion around Al3Fe intermetallic phases in both WIS and ILs. This implies that the presence of Al3Fe particles allows the electrolyte to break the oxide barrier and access the bulk Al. These results suggests that metallurgical treatments are important to enhance the electrochemical performance of AIB.
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| 10. |
- Arshadi Rastabi, Shahrzad, et al.
(author)
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Porous NiMoO4-NrGO as a Battery-Like Electrode Material for Aqueous Hybrid Supercapacitors
- 2023
-
In: Journal of Composites Science. - : MDPI. - 2504-477X. ; 7:6
-
Journal article (peer-reviewed)abstract
- Recently, much research has investigated nanocomposites and their properties for the development of energy storage systems. Supercapacitor performance is usually enhanced by the use of porous electrode structures, which produce a larger surface area for reaction. In this work, a biocompatible polymer of starch medium was used to create the porous nanostructure. Two powders, i.e., Nickel molybdate/reduced graphene oxide (NiMoO4-rGO) and Nickel molybdate/nitrogen-doped reduced graphene oxide (NiMoO4-NrGO), were synthesized using the deposition method in a medium containing starch, nickel nitrate salts, sodium molybdate, and graphene oxide powder. In terms of electrochemical performance, the NiMoO4-NrGO electrode displayed a higher specific capacitance, i.e., 932 Fg−1 (466 Cg−1), than the NiMoO4-rGO electrode, i.e., 884 Fg−1 (442 Cg−1), at a current density of 1 Ag−1. In fact, graphene oxide sheets could lose more oxygen groups in the presence of ammonia, resulting in increased electrical conductivity. For the asymmetric supercapacitor of NiMoO4-NrGO//AC, the specific capacitance at 1 Ag−1, energy density, and power density were 101.2 Fg−1 (111.32 Cg−1), 17 Wh kg−1, and 174.4 kW kg−1, respectively. In addition, this supercapacitor material displayed a good cycling stability of over 82%.
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| 11. |
- Bond, Luke, et al.
(author)
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Electrically conductive polymer-graphene composite material for selective laser sintering additive manufacturing
- 2024
-
In: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE - The International Society for Optics and Photonics. - 9781510670068
-
Conference paper (peer-reviewed)abstract
- Additive manufacturing is rapidly growing, where selective laser sintering technology dominates for industrial use. In the case of polymer selective laser sintering, polyamide is the standard material. However, polyamide is an electrical insulator, and for specific applications, it would be desirable to be able to manufacture polymer-based electrically conductive parts. Electromagnetic Compatibility is one of the most significant targeted applications, where the introduction of electric vehicles raises new electromagnetic compatibility demands. The goal is, therefore, to develop an electrically conductive composite material for selective laser sintering using graphene as the additive. Composites are prepared by mixing polyamide, graphene, and additives with varying graphene/polyamide ratios. The aim of this investigation is the laser-assisted processing of the resulting graphene/polyamide composites with various parameters to sinter the material, forming a solid conductive structure. The structure is characterized using SEM and resistance measurements. Results show sheet resistance values of about 700Ω/sq after laser-assisted processing with good powder flowability.
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| 12. |
- Busson, P., et al.
(author)
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Ferroelectric liquid crystalline dendrimers : Synthesis, thermal behavior, and electrooptical characterization
- 2001
-
In: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 34:5, s. 1221-1229
-
Journal article (peer-reviewed)abstract
- The preparation and characterization of a series of novel ferroelectric liquid crystalline dendrimers are presented. End-capping of 1-, 2-, and 3-generation dendrimers based on 2,2-bis(hydroxymethyl)propionic acid with mesogens gave surface-functionalized liquid crystalline compounds with 6, 12, and 24 mesogen-containing units, respectively. 4 -((R)-1-Methylheptyloxy)phenyl 4-(4 '-[10(hydroxycarbonyl)decyloxyl phenyl)benzoate was synthesized and used as a mesogen-containing unit. The purity and structure of each compound were determined by H-1 NMR spectroscopy, size exclusion chromatography, and elemental analysis. Differential scanning calorimetry and optical microscopy were used to investigate the mesomorphic properties of the mesogen-functionalized dendrimers. The materials displayed a variety of mesophases, including the smectic C* phase. All the liquid crystalline dendrimers showed ferroelectricity, and tilt angle and spontaneous polarization measurements were performed. The obtained results show that the ferroelectric properties of the materials are independent of the generation number of the dendritic scaffold.
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| 13. |
- Busson, P., et al.
(author)
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Preparation of mesogen-functionalized dendrimers for second-order nonlinear optics
- 2002
-
In: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 35:5, s. 1663-1671
-
Journal article (peer-reviewed)abstract
- Liquid crystalline dendrimers with peripheral mesogen-containing units have been prepared. Multistep synthesis with several selective reactions was used in the preparation of the mesogen-containing molecules, 4-[10-(hydroxycarbonyl)decyloxy]phenyl 4-[4'-(2-(R)-octyloxy)-3'-nitrophenyl]benzo ate and 4-[10-(hydroxycarbonyl)decyloxy]biphenyl 4-[4'-(2-(R)-octyloxy)-3'-nitrophenyl]benzoate. Both molecules possessed an electron-accepting nitro group placed perpendicular to the long axis of the molecules in order to enhance the nonlinear optical activity. A second generation hydroxyl functional aliphatic dendrimer based on the dihydroxy acid, 2,2-bis(hydroxymethyl)propionic acid, was used as dendritic scaffold and was subsequently functionalized with the aforementioned groups. The purity and structure of the two liquid crystalline dendrimers were determined by H-1 NMR spectroscopy, size exclusion chromatography, and elemental analysis. The synthesis of both the mesogen-containing units and the liquid crystalline dendrimers is described in detail. Investigation of the liquid crystalline properties of the materials by differential scanning calorimetry and optical microscopy showed that they exhibited different mesophases, including the chiral smectic C phase. Ferroelectric switching was observed in this tilted phase, and electrooptical properties, including tilt angle and spontaneous polarization measurements, were investigated. Finally, the nonlinear optical properties of one of the materials were preliminary characterized.
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| 14. |
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| 15. |
- Ebadi, Seyed Morteza, et al.
(author)
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A Highly-Efficient and Compact Surface Plasmon Polaritons High-Pass Filter based on MIM waveguides
- 2020
-
In: <em>Frontiers in Optics / Laser Science</em>. - Washington, D.C., United States : Optics Info Base, Optical Society of America. - 9781943580804 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- This letter presents design and simulation results of a highly-efficient and compact plasmonic high-pass filter based on a MIM waveguide. Numerical results reveal that by tailoring structural parameters, desired cut-off wavelength can be chosen.
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| 16. |
- Ebadi, Seyed Morteza, et al.
(author)
-
A Multipurpose and Highly-Compact Plasmonic Filter based on Metal-Insulator-Metal Waveguides
- 2020
-
In: IEEE Photonics Journal. - 1943-0655. ; 12:3
-
Journal article (peer-reviewed)abstract
- A multipurpose and ultra-compact nanoplasmonic wavelength filter based on stub structure in a metal-insulator-metal (MIM) waveguide is suggested and numerically investigated. A novel approach of connecting two stepped-like apertures to both input and output ports is applied to form Fabry-Perot (FP) cavities, which enabled the structure to act as a dual band-pass filter at wavelengths 1310 nm and 1550 nm. It is shown that the variation in cavities’ length allows to realize a long-wavelength cutoff filter, and cutoff wavelength can be easily tuned by adjusting the length of the cavities. Furthermore, it is revealed that increasing the gap between the stepped-like apertures and the cavities provides a triple band-pass at telecom wavelengths, e.g. 1267.5nm, 1414.19 nm, and 1644.7 nm. The tunable broadband high-pass wavelength filter is then achieved while the lengths of stepped-like apertures and stub resonators are set to be identical. Finally, a tunable nearly perfect absorber can be obtained by varying the width of stub resonators. Therefore, because of functionality, size, as well as efficiency the proposed plasmonic filter may greatly contribute to miniaturization of next generation of photonic integrated circuits (PICs), and find applications in on-chip integration and wavelength-division multiplexing (WDM) in optical communication systems.
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| 17. |
- Ebadi, Seyed Morteza, et al.
(author)
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A Reconfigurable and Ultra-Compact Plasmonic Filter based on MIM Waveguides at Optical Channels
- 2020
-
In: <em>OSA Advanced Photonics Congress (AP) 2020</em>. - : Optics Info Base, Optical Society of America. - 9781943580798
-
Conference paper (peer-reviewed)abstract
- This paper reports design and simulation of a tunable highly-efficient reconfigurableplasmonic filter based on MIM waveguides. Simulation results shown that by adjusting structuralparameters, the device can work as a multipurpose optical circuit.
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| 18. |
- Ebadi, Seyed Morteza, et al.
(author)
-
A Tunable and Highly-Efficient Plasmonic Band-Stop Filter at Telecom Wavelengths
- 2021
-
In: 2021 IEEE Research and Applications of Photonics in Defense Conference (RAPID). - Miramar Beach, FL, USA : Institute of Electrical and Electronics Engineers (IEEE). - 9781665446747 - 9781665422239 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- This paper reports design and numerical results of an ultra-compact, efficient and tunable plasmonic band-stop filter based on a metal-insulator-metal waveguide at optical channels. Furthermore, a wide-bandgap can be easily achieved by adjusting the width of the of the stub resonator.
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| 19. |
- Ebadi, Seyed Morteza, et al.
(author)
-
A Tunable Plasmonic Wide Flat-Top Band-Pass Filter based on Trapezoid Resonator at Near-Infrared
- 2021
-
In: OSA Advanced Photonics Congress 2021. - : Optics Info Base, Optical Society of America. - 9781943580941 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- A miniaturized and efficient tunable wide flat-top band-pass filter at NIR is proposed in a MIM plasmonic waveguide. Furthermore, numerical results illustrate that tunability is readily attained by varying length of right-angle trapezoid resonator.
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| 20. |
- Ebadi, Seyed Morteza, et al.
(author)
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A Tunable Wide Flat-Top Band-Pass Plasmonic Filter basedon Tilted T-Junction Resonators at Near-Infrared
- 2021
-
In: 2021 IEEE 21st International Conference on Nanotechnology (NANO). - Montreal, QC, Canada : Institute of Electrical and Electronics Engineers (IEEE). - 9781665441575 - 9781665441568 ; , s. 54-55
-
Conference paper (peer-reviewed)abstract
- A highly efficient and compact wide flat-top band-pass filter at NIR is realized in a MIM plasmonic waveguide.Besides, simulation results reveal that through tuning the length of resonators, a broadband band-pass transmission can beeasily achieved.
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| 21. |
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| 22. |
- Ebadi, Seyed Morteza, et al.
(author)
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An Extremely Miniaturized and Highly-Efficient High-Pass Wavelength Plasmonic Filter at Near-Infrared
- 2020
-
In: <em>Frontiers in Optics / Laser Science</em>. - : Optics Info Base, Optical Society of America. - 9781943580804 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- This letter describes design and numerical simulation of an extremely-compact and efficient high-pass plasmonic filter based on MIM waveguides. Numerical results shown that by tuning structural parameters, desired cut-off wavelengths can be chosen.
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| 23. |
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| 24. |
- Ebadi, Seyed Morteza, et al.
(author)
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Chip-Scale and Tunable Flat-Top Surface Plasmon Polaritons Band-pass Filter at Optical Channels
- 2021
-
In: 2021 IEEE Research and Applications of Photonics in Defense Conference (RAPID). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665446747 - 9781665422239 ; , s. 1-2
-
Conference paper (peer-reviewed)abstract
- We present the design and simulation results of a highly-miniaturized and efficient flat-top plasmonic band-pass filter based on a MIM waveguide. In addition to that, it is revealed that by adjusting the length of stub segment, the desired spectral response can be easily realized.
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| 25. |
- Ebadi, Seyed Morteza
(author)
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Design and Numerical Modelling of Nanoplasmonic Structures at Near-Infrared for Telecom Applications
- 2022
-
Licentiate thesis (other academic/artistic)abstract
- Industrial innovation is mostly driven by miniaturization. As a result of remarkable technological advancements in the fields of equipment, materials and production processes, transistor, the fundamental active component in conventional electronics, has shrunk in size. Semiconductor technology is unique in that all performance metrics are enhanced, while at the same time unit prices are reduced. Moore’s Law, which predicts that the number of components per chip will double every two years, was established in 1965, and the industry has been able to keep up with this prophetic prognosis since. Thermal management, on the other hand, has become a key limiting factor for current electronic circuits and is set to put a stop to Moore’s Law. Given the fact that complementary metal oxide semiconductor (CMOS) scaling is reaching fundamental limits, there are several new alternative processing devices and architectures that have been investigated for both traditional integrated circuit (IC) technologies and novel technologies, including new technologies aimed at contributing to advances in scaling progress and cost reductions in manufacturing operations in the coming decades. These factors will encourage the development of new information processing and memory systems, new technologies for integrating numerous features heterogeneously and new system architectural design layouts, among other things. Energy efficiency is advantageous from a sustainability perspective and for consumer electronics, for which fewer power-hungry components mean longer times between charges and smaller batteries. The creation of novel chip-scale tools that can aid in the transfer of information across optical frequencies and microscale photonics between nanoscale electronic devices is now a possibility. Bridging this technological gap may be achieved by plasmonics. The incorporation of plasmonic, photonic and electrical components on a single chip may lead to a number of innovative breakthroughs. Photonic integrated circuits (PICs) enable the realization of ultra-small, high-efficiency, ultra-responsive and CMOS-compatible devices that can be used in applications ranging from optical wireless communication systems (6G and beyond) and supercomputers to health and energy. This thesis provides a platform from which to design nanoplasmonic devices while facilitating high-transmission and/or absorption efficiency, miniaturized size and the use of near-infrared (NIR) wavelengths for telecom applications. With a significant amount of Internet traffic transmitted optically, communication systems are further tightening the requirements for the development of new optical devices. Several new device structures based on the metal-insulator-metal (MIM) plasmonic waveguide are proposed and investigated using performance metrics. The transmission line theory (TLM) from microwave circuit theory and coupled mode theory (CMT) is studied and employed in the design process of the nanostructures, in particular to address the losses in plasmonic-based devices, which has been the major factor hampering their widespread usage in communication systems. By taking advantage of well-established microwave circuit theory (through new design that paves the way for mitigating these losses and enabling efficient transmission of power flow in the optical devices), we have suggested a number of high-transmission efficiency nanodevices that offer highly competitive performance compared with other platforms. As a result, a promising future for plasmonic technology, which would enable design and fabrication of multipurpose and multifunctional optical devices that are efficient in terms of losses, footprint and capability of integrating active devices, is anticipated.
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| 26. |
- Ebadi, Seyed Morteza, et al.
(author)
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Design of miniaturized wide band-pass plasmonic filters in MIM waveguides with tailored spectral filtering
- 2024
-
In: Optical and quantum electronics. - : Springer Nature. - 0306-8919 .- 1572-817X. ; 56:5
-
Journal article (peer-reviewed)abstract
- This paper reports the design and numerical results of three new extremely compact and efficient flat-top band-pass plasmonic filters operating in the near-infrared region. The proposed structures are realized in metal–insulator-metal plasmonic waveguides based on stub, tilted T-junction and right-angle trapezoid configurations. A built-in parameterized genetic algorithm is applied to maximize the transmission efficiency, while at the same time contributing to shrinking down the size of the device structures. It is shown that the tunability of the optical filters can be realized by modulating their structural parameters to gain control over the band-pass filtering wavelengths. Numerical calculations are conducted based on the finite element method of CST Microwave Studio and demonstrate that the suggested ultra-compact plasmonic waveguide filters offer wide bandwidths of more than 270 nm, 424 nm, and 289 nm, with transmission efficiencies of higher than 80%, 74.2%, and 74.3%, respectively. The sizes of the proposed wavelength filters are 490 nm × 575 nm, 350 nm × 180 nm, and 420 nm × 150 nm, respectively, which make them attractive candidates for applications in high density photonic integrated circuits (PICs). As a result, because of the promising characteristics of the proposed topologies such as their high efficiency, compact size, tunability, and simple structure they may find applications in on-chip integration, laser technology, and multi-photon fluorescence.
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| 27. |
- Engisch, Lutz, et al.
(author)
-
Studies on inkjet ink with confocal Raman microscopy
- 2007
-
Conference paper (peer-reviewed)abstract
- The chemical properties of ink, substrate and the interface between them influence the printing process and the achievable printing quality. Several methods to characterize these properties are developed and used in the recent years. The usage of vibration spectroscopy methods are opening a new way to characterize printouts on the molecular level. The raman spectroscopy, mainly working with visible light and a low level sample preparation, has a high potential in this field. Starting with chemical characterization of the composition up to using this method as an online observation tool in printing systems, a wide area of applications is thinkable. This work presents the first results of using a confocal raman microscope to characterize oil and water based inkjet inks on different substrates. Using the proper measurement parameters, we were able to observe the spreading and penetration of the ink into the substrate. Further work shows the possibility of using the results for three dimensional ink distribution analyzing.
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| 28. |
- Engish, L, et al.
(author)
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Application of Raman spectroscopy and infrared synchrotron radiation for digital print analysis
- 2008
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In: Proceedings of Non-Impact Printing. - : The Society for Imaging Science and Technology. - 9780892082797 ; , s. 449-449
-
Conference paper (other academic/artistic)abstract
- The chemical properties of ink, substrate and the interface between them influence the printing process and the achievable print quality. Several methods to characterize these properties have been developed and used in recent years. The usage of vibrational spectroscopy methods are opening a new way to characterize printouts at the molecular level. The Raman spectroscopy, mainly working with visible light and a low level of sample preparation, has a high potential in this field. In the present work, the use of micro-Raman spectroscopy and synchrotron radiation-based infrared (SR-FTIR) spectro-microscopy offers a powerful, non-destructive method for the study and the identification of inks on paper and the comparison of them to one another without the need for chemical preparation and related laboratory work. Using the proper measurement parameters, the 3-D distribution of ink in paper was studied and related to the spreading and penetration of single inkjet droplets. This research was undertaken at the IR beamline at the Australian Synchrotron, Victoria Australia.
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| 29. |
- Erikson, Arne, et al.
(author)
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Quantification of the second-order nonlinear susceptibility of collagen I using a laser scanning microscope
- 2007
-
In: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 12:4
-
Journal article (peer-reviewed)abstract
- Characteristic changes in the organization of fibrillar collagen can potentially serve as an early diagnostic marker in various pathological processes. Tissue types containing collagen I can be probed by pulsed high-intensity laser radiation, thereby generating second harmonic light that provides information about the composition and structure at a microscopic level. A technique was developed to determine the essential second harmonic generation (SHG) parameters in a laser scanning microscope setup. A rat-tail tendon frozen section was rotated in the xy-plane with the pulsed laser light propagating along the z-axis. By analyzing the generated second harmonic light in the forward direction with parallel and crossed polarizer relative to the polarization of the excitation laser beam, the second-order nonlinear optical susceptibilities of the collagen fiber were determined. Systematic variations in SHG response between ordered and less ordered structures were recorded and evaluated. A 500µm-thick z-cut lithiumniobate (LiNbO3) was used as reference. The method was applied on frozen sections of malignant melanoma and normal skin tissue. Significant differences were found in the values of d22, indicating that this parameter has a potential role in differentiating between normal and pathological processes.
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| 30. |
- Fazio, Valentina, et al.
(author)
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New insights in static and dynamic properties of soluble monolayers
- 2003
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In: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 5223, s. 38-49
-
Journal article (peer-reviewed)abstract
- Abstract In this paper we discuss selected equilibrium and dynamic properties of adsorp-tion layers of soluble surfactants. The surface state has been investigated by nonlinearoptical techniques based on second order χ(2)effects which exhibit a high surface specificityand suppress bulk contributions. The surface tension isotherm σ(c) of the homologousseries of n-alkyldimethylphosphine (n =8 − 12) can be described by Frumkin’s equation ofstate which yields the surface interaction parameter, surface coverage and the correspondingarea per molecule A. The comparison of the surface tension σ at a given area per moleculeA reveals a strong alternation within the homologous series. Odd C2n±1 layers show alower surface tension than the adjacent even members C2n of the homologous series. Thiseffect is also present at low surface coverage (A =1.4nm2) and cannot be attributed to adifferences in the chain-packing within a crystalline state. Infrared-Visible Sum-FrequencyGeneration Spectroscopy (SFGS) has been used to monitor the orientation and chain orderwithin the aliphatic tail. SFGS spectra have been recorded for different chain lengths andat different areas per molecule. The analysis of the spectra yields an order parameterG which is proportional to the number of gauche defects within the aliphatic tail. Theodd-even effect in the surface tension turned out to be accompanied by an odd-even effectin the order parameter G. The data suggest that an ordered structure has a bigger impacton the surface tension than an unordered structure. The odd-even effect is also observedin the orientation of the terminating methyl group as retrieved by polarization dependentSFGS measurements. The data shed some light in the relation between molecular andmacroscopic properties. Furthermore surface dilatational viscoelastic properties of afluorinated amphiphile have been measured by a novel version of the oscillating bubble.The oscillating bubble method generates a non-equilibrium state by a harmonic compressionand expansion of the surface layer formed at the tip of a capillary. The surface state ismonitored by Surface Second Harmonic Generation (SHG). This technique is highly surfacespecific and discriminates between monolayer and subsurface coverage. Our set-up allowsto measure the monolayer coverage under dynamic conditions and to relate this to surfacedilatational viscosity and elasticity. For a purely elastic surface layer the prediction of theLucassen van den Temple model (LvdT) are fulfilled.
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| 31. |
- Gepp, Sebastian, et al.
(author)
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Measuring cockling on-line in high speed inkjet printing
- 2009
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In: International Conference on Digital Printing Technologies. - 9780892082872 ; , s. 521-523
-
Conference paper (peer-reviewed)abstract
- Cockling of paper is unwanted out-of-plane deformation arising from variations in humidity. Paper is typically characterised by measurements of dimensional changes when slowly changing the humidity or by measurements of cockling on printed paper after printing. Here, a novel experimental set-up is presented in which cockling can be measured on-line at high speed in the inkjet printing process. Cockling was recorded as a function of time. It is shown that the cockling is several orders of magnitude higher during printing than after printing. Measurements on three papers are reported.
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| 32. |
- Jonas, Örtegren, et al.
(author)
-
Cone motion viscosity and optical second harmonic generation of ferroelectric liquid crystalline dendrimers
- 2001
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In: Liquid crystals (Print). - : Informa UK Limited. - 0267-8292 .- 1366-5855. ; 28:6, s. 861-868
-
Journal article (peer-reviewed)abstract
- We report second harmonic generation in a ferroelectric liquid crystalline trimer and ferroelectric liquid crystalline dendrimers of first, second and third generation. Thin cells were filled with the compounds by capillary forces at elevated temperature, and cooled from the surface stabilized ferroelectric state to below the glass transition temperature, while kept in an electric field. The cone motion viscosity and the threshold electric field for unwinding of the helix axis of the chiral tilted smectic mesophases were studied separately at elevated temperature, and these data were used to optimize the preparation of the films. The measured response time was between 0.3 and 3 ms, which corresponds to a cone motion viscosity between 0.5 and 50 Pa s. Second harmonic generation was studied both at elevated temperature with an electric field and at room temperature with and without electric field. The first generation dendrimer exhibited a strong increase in the second order non-linear optical response with time at room temperature. The d(23)-coefficient of this dendrimer was approximately four times larger than for the other macromolecules and was 0.045 pm V-1. The relatively large d-coefficient of the first generation dendrimer is ascribed to crystallization, which improved the orientation of the molecular dipoles.
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| 33. |
- Lundberg, Anna, et al.
(author)
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Aggregation of Color pigments by Surface fixation treatment
- 2011
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In: Journal of Imaging Science and Technology. - 1062-3701 .- 1943-3522. ; 55:5, s. 1-8
-
Journal article (peer-reviewed)abstract
- The quality of a printed image is strongly influenced by the physical and the chemical interactions between the ink and the paper. Print quality can be evaluated either by objective measurements using instruments or by visual assessment studies involving panel of observers judging the final print. In this article, the print quality on commercial papers as well as on non-commercial papers with different amounts of salt for surface fixation has been studied. Perceived detail reproduction depends not only on sharp edge definition but also on the level of color saturation (Chroma). Color saturation and edge definition originate from two different ink and paper interaction processes. Color saturation is heavily dependent on ink penetration while edge definition correlates to ink spreading. In order to gain understanding of the performance of surface treatment by salt, large efforts have been put on splitting up of the increase in color saturation (Chroma) and improved edge definition. The printouts have been made with a desktop printer using pigmented inks. Cross section images have been taken with a light microscope to analyze the ink penetration depth. SEM analysis has been made to analyze the aggregation of the pigments on the surface. The print quality measurements have been both objective measurements such as print density and subjective image evaluation using a test panel of observers in a perceptual study. The perceptual study focused on detail reproduction, and efforts were made to separate the influence of the print density from the edge definition on the detail reproduction. The result from this study shows that an increased level of salt as surface fixation improves the detail reproduction due to aggregation of the pigments on the surface and that the ink penetration depth can be reduced by adding salt as surface fixation resulting in a higher print density.
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| 34. |
- Lundberg, Anna, 1977-, et al.
(author)
-
Improved Print quality by Surface fixation of Pigments
- 2010
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In: International Conference on Digital Printing Technologies. - : The Society for Imaging Science and Technology. - 9780892082933 ; , s. 251-255
-
Conference paper (peer-reviewed)abstract
- Inkjet printing is a non impact printing method that deposits a limited amount of ink onto the paper surface. To improve runnabillity and printability the demands on papers ability to rapidly absorb the fluid and make the colorants stay on the surface increase. These demands get more pronounced as the technology develops and the print speed significantly increases. The quality of a printed image is strongly influenced by the physical and the chemical interactions between the ink and the paper. Some print quality parameters can be measured objectively by physical measurements using instruments. Subjective print quality evaluation involves human judgments of the final print.In this article, the print quality on commercial papers as well as on trial papers with different amounts of salt for surface fixation has been studied. The printouts have been made with a desktop printer that uses pigmented inks. The print quality measurements have been both objective measurements such as print density and line quality and subjective image evaluation using a test panel in a perceptual study. The perceptual study focused on detail reproduction, and efforts were made to separate the influence of the print density from the edge definition on the detail reproduction. The study confirms the influence of ink and paper interaction on print quality and the relation to different levels of surface fixation.
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| 35. |
- Lundberg, Anna, 1977-, et al.
(author)
-
Microscale droplet absorption into paper for inkjet printing
- 2011
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In: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 26:1, s. 142-150
-
Journal article (peer-reviewed)abstract
- Digital printing using high-speed inkjet technology puts heavy demands on paper's ability to rapidly absorb the liquid. This is important for both the runability during the printing process and for the print quality. In this article, the dynamics of inkjet droplet absorption and penetration is discussed. The LucasWashburn equation has been applied to experimental results from inkjet printing on paper. The ink absorption on different paper grades is discussed in terms of the physical properties of the surface such as surface energy, surface roughness and porosity. The results of this study indicate that ASA used as internal sizing reduces the absorption speed of water based dye inkjet ink and that evaporation affects the result. The Lucas-Washburn equation can be used to some extent for describing micro-scale droplet absorption into paper, depending on the properties of the paper.
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| 36. |
- Lundberg, Anna, 1977-, et al.
(author)
-
On the Effect of Variations in paper composition on print quality
- 2009
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In: International Conference on Digital Printing Technologies 2009. - : The Society for Imaging Science and Technology. - 9780892082872 ; , s. 316-319
-
Conference paper (peer-reviewed)abstract
- During the last few years, digital printing technology has begun to play a significant role in the printing industry due to the quest for short runs and variable data printing. Digital printing using inkjet technology makes heavy demands on the paper's ability to rapidly absorb liquid and thereby increases the need to understand what parameters that affect the dynamics and interactions between paper and ink and how print quality is affected by these parameters. In this paper, the print quality for nine pilot papers with varying composition and eight different commercial papers has been studied. The printouts have been made with two small office/Home office printers; the print quality measurements for this study have been line quality-measurements and color -gamut volume measurements. The line quality and the color gamut volume for the commercial papers and the pilot papers are discussed.
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| 37. |
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| 38. |
- Niga, Petru, et al.
(author)
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Hybrid package printing. Assessment of the influence of paper media parameters for inkjet printing on flexographic printed paper.
- 2014
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In: Narrow WebTech. - : G&K Tech Media GmbH. - 1617-206X. ; :1, s. 16-22
-
Journal article (peer-reviewed)abstract
- Hybrid printing combining inkjet technology with flexography can be used to add customer specific information in the production of packaging and print. However, in order to improve print quality a comprehensive understanding of the mechanisms governing print quality is required. In this work, inkjet printing using three aqueous inkjet inks was performed on top of flexographic printouts on four paper substrates. The flexographic film contained tone values ranging from 0 to 100% ink coverage. Line quality and print density of the inkjet print were evaluated in order to estimate the influence of paper parameters on the print quality. Specifically, it was found that for the system studied, the flexographic film essentially dictates the surface energy while keeping the porosity and the surface roughness of the paper unaltered. These findings are further supported by micrograph images.
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| 39. |
- Niga, Petru, et al.
(author)
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Hybrid printing : paper media for combined flexographic and inkjet printing
- 2012
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In: Conference proceedings International Paper Physics Conference. - Stockholm : Innventia. ; , s. 79-81
-
Conference paper (other academic/artistic)abstract
- Hybrid printing combining inkjet technology with flexography can be used to add customer specific information into the production of packaging and print. However, in order to improve print quality, a comprehensive understanding of the mechanisms governing print quality is required. In this work, inkjet printing using three aqueous inkjet inks was performed on top of flexographic printouts on four paper substrates. For comparative reasons, inkjet printouts were made on the four papers as well. The flexographic film contained tone values ranging from 0 to 100% ink coverage. Line width and print density of the inkjet printouts were evaluated. It was found that paper characteristics such as surface energy, porosity, absorption coefficient and surface roughness play an important role in defining the final print quality. These findings are further supported by micrograph images.
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| 40. |
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| 41. |
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| 42. |
- Olsen, Martin, 1971-, et al.
(author)
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Frequency and voltage response of a wind-driven fluttering triboelectric nanogenerator
- 2019
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
-
Journal article (peer-reviewed)abstract
- Triboelectric nanogenerators (TENG:s) are used as efficient energy transducers in energy harvesting converting mechanical energy into electrical energy. Wind is an abundant source of mechanical energy but how should a good triboelectric wind harvester be designed? We have built and studied a TENG driven by air flow in a table-top sized wind tunnel. Our TENG constitutes of a plastic film of size10 cm × 2 cm which is fluttering between two copper electrodes generating enough power to light up a battery of LED:s. We measured the voltage and frequency of fluttering at different wind speeds from zero up to 8 m/s for three electrode distances 6 mm, 10 mm and 14 mm. We found that the frequency increases linearly with the wind speed with a cutoff at some low speed. Power was generated already at 1.6 m/s. We seem to be able to explain the observed frequency dependence on wind speed by assuming excitation of the film into different harmonics in response to von Kármán vortices. We also find that the voltage increase linearly with frequency. We anticipate that TENG:s of this design could be useful both as generators and speed sensors because they work at low air speeds.
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| 43. |
- Olsen, Martin, 1971-
(author)
-
Nanomechanics – Quantum Size Effects, Contacts, and Triboelectricity
- 2019
-
Doctoral thesis (other academic/artistic)abstract
- Nanomechanics is different from the mechanics that we experience in everyday life. At the nano-scale, typically defined as 1 to 100 nanometers, some phenomena are of crucial importance, while the same phenomena can be completely neglected on a larger scale. For example, the feet of a gekko are covered by nanocontacts that yield such high adhesion forces that the animal can run up on walls and even on the ceiling. At small enough distances, matter and energy become discrete, and the description of the phenomena occurring at this scale requires quantum mechanics. However, at room temperature the transitions between quantized energy levels may be concealed by the thermal vibrations of the system. As two surfaces approach each other and come into contact, electrostatic forces and van der Waals forces may cause redistribution of matter at the nano level. One effect that may occur upon contact between two surfaces is the triboelectric effect, in which charge is transferred from one surface to the other.This effect can be used to generate electricity in triboelectric nanogenerators (TENGs), where two surfaces are repeatedly brought in and out of contact, and where the charge transfer is turned into electrical energy.This thesis concerns nanomechanics addressing whether quantum mechanics play a role in elastic deformation, as well as various mechanical aspects of nanocontacts including electric charging. The objectives are to contribute to the understanding when quantum effects are of importance at the nanolevel, increase the fundamental understanding of the mechanisms responsible for triboelectric phenomena and apply the triboelectric effect to a wind harvesting device.For more insight into whether quantum effects are of importance in nanomechanics, we use a one dimensional jellium model and the standard beam theory allowing the spring constant of an oscillating nanowire cantilever to be calculated. As the nanowire bends, more electron states fit in its cross section, giving rise to an amplitude dependent resonance frequency of the nanowire oscillations.Furthermore, a model for electric field induced surface diffusion of adatoms was developed. The model takes electrostatic forces and van der Waals forces into account as a voltage is applied between a scanning tunneling microscope tip and a sample. The calculated force on the adatoms at the surface of the sample, which is stemming from the inhomogeneous electric field and the dipole moment of the adatoms, is relatively small, but due to thermal vibrations adatoms diffuse and form mounds at the sample.When bringing two different materials into contact, the difference in triboelectric potentials between the materials results in electric charging. To increase the understanding of triboelectricity, a two-level Schottky model, assuming ion transfer, was developed to describe the temperature dependence of the triboelectric effect for a TENG. The two levels correspond to the binding energy for ions on the two surfaces that are brought into contact, where the difference in binding energy enters the Boltzmanndistribution. The model describes the decreasing triboelectric effect in TENG:s with increasing temperature as described in the literature, and results in a separation energy, which is of the right order of magnitude for physically adsorbed atoms.It was recently demonstrated that TENGs can convert wind energy into electrical energy. Here, a TENG based on a plastic film fluttering between two copper electrodes was constructed. It was found that the frequency of the the fluttering film increases linearly with the wind speed. TENG:s designed in this way generate electricity already at low wind speed, and we therefore expect such TENG:s to be useful both as generators and speed sensors in the future.While quantum mechanics is of importance in a limited number of nanomechanical systems, nanocontacts have a broader meaning, and are crucial for the understanding of triboelectric phenomena. We anticipate that the findings in this thesis will contribute to a better understanding of nanomechanics, in particular the mechanism of triboelectricity.
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| 44. |
- Olsen, Martin, 1971-, et al.
(author)
-
Schottky model for triboelectric temperature dependence
- 2018
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
-
Journal article (peer-reviewed)abstract
- The triboelectric effect, charging by contact, is the working principle in a device called a triboelectric nanogenerator. They are used as efficient energy transducers in energy harvesting. In such generators the charging of surfaces at contact is followed by a separation of the surfaces increasing the electrical energy which can subsequently be used. Different materials have different triboelectric potentials leading to charging at contact. The temperature dependence of the charging has just recently been studied: the triboelectric effect is decreasing with temperature for a generator of Al-PTFE-Cu. Here, we suggest a mechanism to explain this effect assuming ion transfer using a two-level Schottky model where the two levels corresponds to the two surfaces. The difference in binding energy for ions on the two surfaces then enters the formula for charging. We fit the triboelectric power density as a function of temperature obtained from a two-level Schottky model to measured data for nanogenerators made of Al-PTFE-Cu found in three references. We obtain an average separation energy corresponding to a temperature of 365 K which is of the right magnitude for physically adsorbed atoms. We anticipate that this model could be used for many types of triboelectric nanogenerators.
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| 45. |
- Patil, Rohan, 1983-
(author)
-
A scalable furnace technique to grow silicon nanoparticles for high-performance Li-ion battery anodes
- 2023
-
Licentiate thesis (other academic/artistic)abstract
- Lithium-ion batteries are one of the key technologies to address the global climate challenge. Higher battery capacity could also be seen as indirectly influencing the entire value chain. One way to increase capacity is to add silicon to the graphite anode, since silicon can store much more lithium ions than graphite. Several high-performance schemes utilizing silicon nano solutions have been demonstrated. However, industrial-scale implementation of these solutions still poses a challenge. In this thesis I present a novel scalable furnace technique to create silicon nanoparticles attached to the nanographite flakes. The novel furnace technique allows compatibility with already established industrial-scale electrode manufacturing techniques, presenting itself as a promising strategy for engineering electrodes with endurable performance.
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| 46. |
- Patil, Rohan, 1983-, et al.
(author)
-
Highly Stable Cycling of Silicon-Nanographite Aerogel-Based Anode for Lithium-Ion Batteries
- 2021
-
In: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 6:10, s. 6600-6606
-
Journal article (peer-reviewed)abstract
- Silicon anodes are considered as promising electrode materials for next-generation high-capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge−discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in the recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nano graphite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.
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| 47. |
- Phadatare, Manisha R., et al.
(author)
-
Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries
- 2019
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
-
Journal article (peer-reviewed)abstract
- To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.
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| 48. |
- Razaz, Ghadir, et al.
(author)
-
Aluminum Alloy Anode with Various Iron Content Influencing the Performance of Aluminum-Ion Batteries
- 2023
-
In: Materials. - : MDPI AG. - 1996-1944. ; 16:3
-
Journal article (peer-reviewed)abstract
- Considerable research has been devoted to the development of cathode materials for Al-ion batteries, but challenges remain regarding the behavior of aluminum anodes. Inert oxide (Al2O3) film on Al surfaces presents a barrier to electrochemical activity. The structure of the oxide film needs to be weakened to facilitate ion transfer during electrochemical activity. This study addresses oxide film challenges by studying Al alloy anodes with different iron content. The results reveal that using an anode of 99% Al 1% Fe in a cell increases the cycling lifetime by 48%, compared to a 99.99% Al anode. The improvement observed with the 99% Al 1% Fe anode is attributed to its fractional surface area corrosion being about 12% larger than that of a 99.99% Al anode. This is coupled to precipitation of a higher number of Al3Fe particles, which are evenly scattered in the Al matrix of 99% Al 1% Fe. These Al3Fe particles constitute weak spots in the oxide film for the electrolyte to attack, and access to fresh Al. The addition of iron to an Al anode thus offers a cheap and easy route for targeting the oxide passivating film challenge in Al-ion batteries.
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| 49. |
- Rehberger, Marcus, et al.
(author)
-
VDP on packaging : Elementary velocity study on inkjet-printed papers for corrugated board production
- 2010
-
In: Proceedings of the Technical Association of the Graphic Arts, TAGA. - 9781935185024
-
Conference paper (peer-reviewed)abstract
- The idea of the “HybSpeed Printing” Project at Innventia AB is to facilitate the combination of a conventional printing process with inkjet printing, in-line, in the converting process. Inkjet print is “the” printing technique for adding variable data to a conventional printed layout (van Daele, 2005). It is already available, but the current processes do not guarantee high quality print at high speed, but the constant progress in inkjet technology will mean that this is soon provided. The aim of the present project is to evaluate the practicability of attaining high quality variable data print (VDP) at high speed. In 2008, an exploratory test was conducted on a Kodak Versamark DP5240 in Örnsöldsvik, Sweden, in cooperation with the Digital Printing Centre (DPC). As already mentioned, speed is probably the greatest issue facing the inkjet system. Flexo presses, for example, are running at a speed of 1000-1500 fpm, but the maximum speed of the inkjet test rig at DPC is 1000 fpm (5.08 m/s). Hence, this inkjet unit almost achieves the minimum requirements in speed. The question is how does the inkjet print quality at maximum speed differ from that at lower speed? The results reveal that speed has a slight influence on the print quality and that the line thickness and print density can be compensated for by changing the print layout. To minimize the line raggedness at high speed, other counter-measures have to be considered. However, the choice of paper had a greater influence and these issues are also discussed.
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| 50. |
- Wandtke, K.-D., et al.
(author)
-
The influence of the sublayer on the surface dilatational modulus
- 2005
-
In: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 261:1-3, s. 75-83
-
Journal article (peer-reviewed)abstract
- The frequency dependence of the surface dilatational modulus is valuable for an assessment of surface models of aqueous surfactant solutions. Precise data of the complex surface dilatational modulus can be obtained with an oscillating bubble device. The technique covers a broad frequency range (3–500 Hz) and has been used to study several surfactant systems. So far, the surface rheology has been mainly described by the well-established Lucassen–van den Tempel–Hansen model (LvdTH model). This model can describe the dynamic surface behavior of many surfactant solutions, but a few puzzles remain. First, the measured data do not match the corresponding model fit, in particular near the CMC or the limit of solubility. Moreover, the frequency dependence of the modulus of some surfactant systems provides clear evidence for the existence of an intrinsic surface dilatational viscosity. All contradictions and observational facts can be bridged by applying the Guggenheim convention with an extended surface phase, which explicitly includes a molecular exchange between the monolayer and an adjacent sublayer as intrinsic properties. Neglecting these substructures one obtains the classical Gibbs model of the surface. Furthermore, the model takes into consideration the dissipative losses in the extended effective surface layer. The significance of this finding requires an independent verification; therefore, independent measurements with surface second harmonic generation, SHG, have been carried out. SHG is a non-linear optical technique with an inherent surface specificity. It can be used for the measurement of the monolayer coverage under dynamic conditions. SHG measurements carried out on an oscillating bubble provide evidences for the extended surface model. The surface dilatational viscosity is a system quantity which has consequences for variety of technological processes such as high speed coating processes. Furthermore, it could be demonstrated that surface dilatational viscosity is a prerequisite for stable foams. The paper discusses also the surface properties of high concentrated solutions and solutions of surfactant/polyelectrolyte mixtures, which require a different treatment.
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