| 1121. |
- Kalbfleisch, Sebastian, et al.
(författare)
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X-ray in-line holography and holotomography at the NanoMAX beamline
- 2022
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Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 29, s. 224-229
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Tidskriftsartikel (refereegranskat)abstract
- Coherent X-ray imaging techniques, such as in-line holography, exploit the high brilliance provided by diffraction-limited storage rings to perform imaging sensitive to the electron density through contrast due to the phase shift, rather than conventional attenuation contrast. Thus, coherent X-ray imaging techniques enable high-sensitivity and low-dose imaging, especially for low-atomic-number (Z) chemical elements and materials with similar attenuation contrast. Here, the first implementation of in-line holography at the NanoMAX beamline is presented, which benefits from the exceptional focusing capabilities and the high brilliance provided by MAX IV, the first operational diffractionlimited storage ring up to approximately 300 eV. It is demonstrated that in-line holography at NanoMAX can provide 2D diffraction-limited images, where the achievable resolution is only limited by the 70 nm focal spot at 13 keV X-ray energy. Also, the 3D capabilities of this instrument are demonstrated by performing holotomography on a chalk sample at a mesoscale resolution of around 155 nm. It is foreseen that in-line holography will broaden the spectra of capabilities of MAX IV by providing fast 2D and 3D electron density images from mesoscale down to nanoscale resolution.
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| 1122. |
- Kalisch, Henrik, et al.
(författare)
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Numerical study of traveling-wave solutions for the Camassa-Holm equation
- 2005
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Ingår i: Chaos, Solitons & Fractals. - : Elsevier BV. - 0960-0779 .- 1873-2887. ; 25:2, s. 287-298
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Tidskriftsartikel (refereegranskat)abstract
- We explore numerically different aspects of periodic traveling-wave solutions of the Camassa-Holm equation. In particular, the time evolution of some recently found new traveling-wave solutions and the interaction of peaked and cusped waves is studied.
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| 1123. |
- Kamal, Chinnathambi, et al.
(författare)
-
Core-Level Binding Energy Reveals Hydrogen Bonding Configurations of Water Adsorbed on TiO2 (110) Surface
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 126:1
-
Tidskriftsartikel (refereegranskat)abstract
- Using x-ray photoelectron spectroscopy of the oxygen 1s core level, the ratio between intact (D2O) and dissociated (OD) water in the hydrated stoichiometric TiO2 (110) surface is determined at varying coverage and temperature. In the submonolayer regime, both the D2O:OD ratio and the core-level binding energy of D2O (Delta BE) decrease with temperature. The observed variations in Delta BE are shown with density functional theory to be governed crucially and solely by the local hydrogen bonding environment, revealing a generally applicable classification and details about adsorption motifs.
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| 1124. |
- Kaminski, Clemens, et al.
(författare)
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Flame growth and wrinkling in a turbulent flow
- 2000
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Ingår i: Applied physics. B, Lasers and optics (Print). - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 71:5, s. 711-716
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Tidskriftsartikel (refereegranskat)abstract
- High-speed planar laser-induced fluorescence (PLIF) and 3-D large eddy simulations (LES) are used to study turbulent flame kernel growth, wrinkling and the formation of separated flame pockets in methane/air mixtures. Turbulence was effected by a set of rotary fans situated in a cylindrical enclosure. Flame wrinkling was followed on sequential 2-D OH images captured at kHz repetition rates. Under stoichiometric conditions and low turbulence levels the flame kernel remains singly connected and close to spherical in shape. By increasing turbulence or reducing the stoichiometry of the mixture the formation of separated pockets could be observed and studied. The mechanisms behind these phenomena are investigated qualitatively by LES of a level-set G-equation describing the flame surface propagation in turbulent flows.
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| 1125. |
- Kamra, Tripta, et al.
(författare)
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Photoconjugation of Molecularly Imprinted Polymer Nanoparticles for Surface-Enhanced Raman Detection of Propranolol
- 2015
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 7:49, s. 27479-27485
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Tidskriftsartikel (refereegranskat)abstract
- We report a simple and versatile method to covalently immobilize molecularly imprinted polymer (MIP) nanoparticles on a Raman active substrate (Klarite) using a disulfide-derivatized perfluorophenylazide (PFPA-disulfide). Gold-coated Klarite was functionalized with PFPA-disulfide via a gold sulfur bond. Upon light radiation, the available azido groups were converted to highly reactive singlet perfluorophenyl nitrene that undergoes a CH insertion reaction and form covalent bonds with the MIP nanoparticles. The resulting surfaces were characterized using scanning electron microscopy and surface enhanced Raman spectroscopy to study the morphology and template affinity of the surfaces, respectively. The Raman measurements clearly show a dose-responsive signal when propranolol binds to the MIP surface. Because the MIP particles were covalently attached to the Raman active substrate, the sensing surface was stable and could be reused after regeneration in acetic acid solution. The MIP-based Raman sensor was used successfully to detect propranolol in urine samples (7.7 X 10(-4) M). Our results show that the high selectivity of MLPs and the fingerprint Raman identification can be integrated into a compact sensing unit using high-efficiency photoconjugation. Thus, the method proposed is reliable, efficient and fast for fabricating label-free chemical sensors.
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| 1126. |
- Kanje, Sara, 1986-, et al.
(författare)
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Protein engineering allows for mild affinity-based elution of therapeutic antibodies
- 2018
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Ingår i: Journal of Molecular Biology. - : Elsevier. - 0022-2836 .- 1089-8638. ; 430:18, s. 3427-3438
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Tidskriftsartikel (refereegranskat)abstract
- Presented here is an engineered protein domain, based on Protein A, that displays a calcium-dependent binding to antibodies. This protein, ZCa, is shown to efficiently function as an affinity ligand for mild purification of antibodies through elution with ethylenediaminetetraacetic acid. Antibodies are commonly used tools in the area of biological sciences and as therapeutics, and the most commonly used approach for antibody purification is based on Protein A using acidic elution. Although this affinity-based method is robust and efficient, the requirement for low pH elution can be detrimental to the protein being purified. By introducing a calcium-binding loop in the Protein A-derived Z domain, it has been re-engineered to provide efficient antibody purification under mild conditions. Through comprehensive analyses of the domain as well as the ZCa–Fc complex, the features of this domain are well understood. This novel protein domain provides a very valuable tool for effective and gentle antibody and Fc-fusion protein purification
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| 1127. |
- Kao, ChungYao, et al.
(författare)
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Simple stability criteria for systems with time-varying delays
- 2004
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Ingår i: Automatica. - : Elsevier BV. - 0005-1098 .- 1873-2836. ; 40:8, s. 1429-1434
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers the problem of checking stability of linear feedback systems with time-varying but bounded delays. Simple but powerful criteria of stability are presented for both continuous-time and discrete-time systems. Using these criteria, stability can be checked in a closed loop Bode plot. This makes it easy to design the system for robustness.
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| 1128. |
- Kao, Chung-Yao, et al.
(författare)
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A MATLAB toolbox for robustness analysis
- 2004
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Ingår i: Proceedings of the IEEE International Symposium on Computer-Aided Control System Design. ; , s. 297-302, s. 297-302
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Konferensbidrag (refereegranskat)abstract
- Verification of control systems is often done using extensive simulation. This gives the engineer useful qualitative information about the system performance. However, simulation cannot be used to rigorously prove stability and robustness of the system. Such properties can only be verified using mathematical analysis which for many realistic systems becomes rather involved. This paper presents the MATLAB toolbox IQCβ. It provides a user friendly interface for advanced semi-automatic systems analysis.
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| 1129. |
- Karayiannidis, Yiannis, 1980, et al.
(författare)
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Operational space robot control for motion performance and safe interaction under Unintentional Contacts
- 2016
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Ingår i: 2016 European Control Conference (ECC);Aalborg, Denmark, 29 June - 1 July 2016. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 407-412, s. 407-412, s. 407-412
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Konferensbidrag (refereegranskat)abstract
- A control law achieving motion performance of quality and compliant reaction to unintended contacts for robot manipulators is proposed in this work. It achieves prescribed performance evolution of the position error under disturbance forces up to a tunable level of magnitude. Beyond this level, it deviates from the desired trajectory complying to what is now interpreted as unintentional contact force, thus achieving enhanced safety by decreasing interaction forces. The controller is a passivity model based controller utilizing an artificial potential that induces vanishing vector fields. Simulation results with a three degrees of freedom (DOF) robot under the control of the proposed scheme, verify theoretical findings and illustrate motion performance and compliance under an external force of short duration in comparison with a switched impedance scheme.
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| 1130. |
- Karimi, Mohammad, 1988-, et al.
(författare)
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Intersubband Quantum Disc-in-Nanowire Photodetectors with Normal-Incidence Response in the Long-Wavelength Infrared
- 2018
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Ingår i: Nano letters (Print). - Washington : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 18:1, s. 365-372
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires have great potential for realizing broadband photodetectors monolithically integrated with silicon. However, the spectral range of such detectors has so far been limited to selected regions in the ultraviolet, visible, and near-infrared regions. Here, we report on the first intersubband nanowire heterostructure array photodetectors exhibiting a spectrally resolved photoresponse from the visible to long-wavelength infrared. In particular, the infrared response from 3 to 20 μm is enabled by intersubband transitions in low-bandgap InAsP quantum discs synthesized axially within InP nanowires. The intriguing optical characteristics, including unexpected sensitivity to normal incident radiation, are explained by excitation of the longitudinal component of optical modes in the photonic crystal formed by the nanostructured portion of the detectors. Our results provide a generalizable insight into how broadband nanowire photodetectors may be designed and how engineered nanowire heterostructures open up new, fascinating opportunities for optoelectronics.
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