Article
Refine
Year of publication
- 2024 (16)
- 2023 (59)
- 2022 (75)
- 2021 (80)
- 2020 (93)
- 2019 (95)
- 2018 (83)
- 2017 (72)
- 2016 (78)
- 2015 (83)
- 2014 (93)
- 2013 (96)
- 2012 (80)
- 2011 (128)
- 2010 (119)
- 2009 (119)
- 2008 (102)
- 2007 (94)
- 2006 (86)
- 2005 (99)
- 2004 (131)
- 2003 (74)
- 2002 (92)
- 2001 (88)
- 2000 (84)
- 1999 (88)
- 1998 (82)
- 1997 (79)
- 1996 (70)
- 1995 (68)
- 1994 (76)
- 1993 (51)
- 1992 (48)
- 1991 (25)
- 1990 (35)
- 1989 (38)
- 1988 (54)
- 1987 (32)
- 1986 (18)
- 1985 (32)
- 1984 (18)
- 1983 (17)
- 1982 (26)
- 1981 (18)
- 1980 (35)
- 1979 (23)
- 1978 (30)
- 1977 (14)
- 1976 (13)
- 1975 (10)
- 1974 (3)
- 1972 (2)
- 1971 (1)
- 1968 (1)
Document Type
- Article (3226) (remove)
Language
- English (3226) (remove)
Keywords
- Einspielen <Werkstoff> (7)
- avalanche (5)
- Earthquake (4)
- FEM (4)
- Finite-Elemente-Methode (4)
- LAPS (4)
- biosensors (4)
- field-effect sensor (4)
- frequency mixing magnetic detection (4)
- CellDrum (3)
- Heparin (3)
- Label-free detection (3)
- additive manufacturing (3)
- capacitive field-effect sensor (3)
- hydrogen peroxide (3)
- magnetic nanoparticles (3)
- shakedown analysis (3)
- snow (3)
- tobacco mosaic virus (TMV) (3)
- Acyl-amino acids (2)
Institute
- Fachbereich Medizintechnik und Technomathematik (1343)
- INB - Institut für Nano- und Biotechnologien (501)
- Fachbereich Chemie und Biotechnologie (466)
- IfB - Institut für Bioengineering (408)
- Fachbereich Elektrotechnik und Informationstechnik (401)
- Fachbereich Energietechnik (360)
- Fachbereich Luft- und Raumfahrttechnik (247)
- Fachbereich Maschinenbau und Mechatronik (147)
- Fachbereich Wirtschaftswissenschaften (106)
- Fachbereich Bauingenieurwesen (68)
- Solar-Institut Jülich (43)
- ECSM European Center for Sustainable Mobility (27)
- Sonstiges (21)
- Institut fuer Angewandte Polymerchemie (20)
- Freshman Institute (17)
- Nowum-Energy (16)
- MASKOR Institut für Mobile Autonome Systeme und Kognitive Robotik (15)
- Fachbereich Gestaltung (12)
- Fachbereich Architektur (9)
- ZHQ - Bereich Hochschuldidaktik und Evaluation (5)
The absorption coefficient of VAI3, FeAI, NiAI, NiAl2, CuAI2, PrAl2, and of disordered V–AI (16 at% AI, 28%, 41%) and Fe–AI (11%) alloys has been measured in the region of the M₂,₃ absorption of the transition metals and the Labsorption of AI. The strong changes of the AI spectrum in the region of the 100 eV maximum upon alloying are explained as another evidence of the EXAFS (extended X-ray absorption fine structure) nature of these structures. The broad, prominent absorption peaks from the 3p excitations in V and Fe and from the 4d excitations in Pr are influenced only little on allyoing and thus appear to be of atomic origin. The fine structure at the onset of the Pr 4d transitions is identical in the metal and the alloy but differs from that of Pr oxide. The only M₂,₃ edge which is detectably shifted is that of Ni (up to 2.1 eV), whereas the onset of the AI L₂,₃ edge is shifted in all the alloys (up to 1.1 eV). The shifts are interpreted in accordance with X-ray fluorescence and nuclear resonance measurements as changes of the density of states in the valence band of the alloys.
Photoabsorption of alloys of Al with transition metals V, Fe, Ni and Cu and Pr near the Al L₂,₃-edge
(1974)
The onset of Al 2p transitions of VAl₃, FeAl, NiAl, NiAl₃, CuAl₂, PrAl₂ and the disordered alloys V-Al (16 at % Al, 28%, 41%), Fe-Al (11%) is shifted up to 1.1 eV. New pronounced structure develops close to the onset which for NiAl agrees with a density of states calculation by Connolly and Johnson.
Photoelectrochemical (PEC) biosensors are a rather novel type of biosensors thatutilizelighttoprovideinformationaboutthecompositionofananalyte,enablinglight-controlled multi-analyte measurements. For enzymatic PEC biosensors,amperometric detection principles are already known in the literature. In con-trast, there is only a little information on H+-ion sensitive PEC biosensors. Inthis work, we demonstrate the detection of H+ions emerged by H+-generatingenzymes, exemplarily demonstrated with penicillinase as a model enzyme on atitanium dioxide photoanode. First, we describe the pH sensitivity of the sensorand study possible photoelectrocatalytic reactions with penicillin. Second, weshow the enzymatic PEC detection of penicillin.
A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500 μm, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immobilized on a sapphire microsphere and hybridized with a 29-mer target DNA. Whispering gallery modes (WGMs) were monitored before the sapphire was functionalized with DNA and after it was functionalized with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The shift in WGMs from the surface modification with DNA was measured and correlated well with the estimated thickness of the add-on DNA layer. It is shown that ssDNA is more uniformly oriented on the sapphire surface than dsDNA. In addition, it is shown that functionalization of the sapphire spherical surface with DNA does not affect the quality factor (Q≈104) of the sapphire microspheres. The use of sapphire is especially interesting because this material is chemically resilient, biocompatible, and widely used for medical implants.
In this study we show an optical biosensor concept, based on elastic light scattering from sapphire microspheres. Transmitted and elastic scattering intensity of the microspheres (radius 500 μm, refractive index 1.77) on an optical fiber half coupler is analyzed at 1510 nm. The 0.43 nm angular mode spacing of the resonances is comparable to the angular mode spacing value estimated using the optical size of the microsphere. The spectral linewidths of the resonances are in the order of 0.01 nm, which corresponds to quality factors of approximately 105. A polydopamine layer is used as a functionalizing agent on sapphire microspherical resonators in view of biosensor implementation. The varying layer thickness on the microsphere is determined as a function of the resonance wavelength shift. It is shown that polymer functionalization has a minor effect on the quality factor. This is a promising step toward the development of an optical biosensor.