Search Results - (Author, Cooperation:H. Giessen)
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1Latest Papers from Table of Contents or Articles in PressN. Liu ; M. Hentschel ; T. Weiss ; A. P. Alivisatos ; H. Giessen
American Association for the Advancement of Science (AAAS)
Published 2011Staff ViewPublication Date: 2011-06-18Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Algorithms ; *Biophysical Phenomena ; DNA/chemistry ; Gold ; *Nanostructures ; Nanotechnology/*methods ; *Optical Phenomena ; Proteins/chemistry ; Spectroscopy, Fourier Transform InfraredPublished by: -
2Articles: DFG German National LicensesLippitz, M. ; Schüttler, M. ; Giessen, H. ; Born, M. ; Rühle, W. W.
[S.l.] : American Institute of Physics (AIP)
Published 1999Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: The distance between sample and probe in a scanning near-field optical microscope is regulated via tracing the shear-force on the tip which is glued to a tuning fork piezo. A lock-in technique is used. We demonstrate that the bandwidth of the control loop is increased if not only amplitude or phase, but a favorable combination of both is used as feedback signal. The enhancement of bandwidth is connected with a reduction of signal-to-noise ratio. The optimum combination of both, bandwidth and signal-to-noise ratio, can be adjusted purely electronically to the specific needs of an experiment. A theoretical model is developed that discloses the relation between the mechanical and electrical properties of the combination of tuning fork and fiber tip. The frequency response of the shear-force detection system is calculated with a numerical simulation based on this model. Experimental frequency response curves are well fitted by these simulations. Our results are especially important for low-temperature scanning microscopy, where the bandwidth enhancement is essential for obtaining a reasonable scanning speed. © 1999 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesSchweitzer, B. ; Wegmann, G. ; Giessen, H. ; Hertel, D. ; Bässler, H. ; Mahrt, R. F.
Woodbury, NY : American Institute of Physics (AIP)
Published 1998Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We report on stimulated emission from a solid conjugated methyl-substituted ladder-type poly(paraphenylene). The threshold for stimulated emission as well as the spectral narrowing is measured. Upon exciting within the low energy tail of the S1-S0 (0–0) absorption band narrow emission lines offset from the excitation by the energies of the dominant vibrational modes are observed. From these measurements we conclude that vibronic sublevels play a major role in the optical gain mechanism. Hence, the gain mechanism can be explained in terms of molecularly excited states. © 1998 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesGiessen, H. ; Fluegel, B. ; Mohs, G. ; Peyghambarian, N. ; Sprague, J. R. ; Micic, O. I. ; Nozik, A. J.
Woodbury, NY : American Institute of Physics (AIP)
Published 1996Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Colloidal suspensions of InP quantum dots (diameters 25 and 35 A(ring)) show steplike absorption spectra which are blue-shifted by about 1 eV with respect to bulk material. Time resolved femtosecond spectroscopy at room temperature identifies the first quantum confined state. The nonlinear bleaching signal rises within 300 fs and persists longer than 200 ps. © 1996 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesMohs, G. ; Fluegel, B. ; Giessen, H. ; Meissner, K. ; Khitrova, G. ; Gibbs, H. ; Peyghambarian, N.
Woodbury, NY : American Institute of Physics (AIP)
Published 1996Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Gain for less than one picosecond is observed in a type II GaAs/AlAs multiple quantum well and compared to a type I multiple quantum well under the same conditions. A sophisticated three-beam experiment is used to unambiguously determine the internal gain of the samples. This method is capable of measuring very small amounts of gain and applicable to a wide variety of situations. The observations are well explained by a simple carrier scattering model. © 1996 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesBUCX, M. J. L. ; SNIJDERS, C. J. ; GEEL, R. T. M. ; ROBERS, C. ; GIESSEN, H. ; ERDMANN, W. ; STIJNEN, T.
Oxford, UK : Blackwell Publishing Ltd
Published 1994Staff ViewISSN: 1365-2044Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: MedicineNotes: We determined the forces on the maxillary incisors during routine laryngoscopy in 65 adult patients. The forces were measured by a strain gauge based sensor positioned between the handle and the blade of the laryngoscope. The mean maximal force acting on the maxillary incisors was 49 N. In patients without maxillary incisors, the force acting on the gums was significantly lower at 21N (p 〈 0.001). These results suggest that, despite traditional advice to the contrary, a levering movement of the laryngoscope, using the maxillary incisors (or gums) as a fulcrum, is common practice. Biomechanical analysis revealed that, although levering is not the preferred movement, it is an efficient way of bringing the glottis into view. These results may have implications for future laryngoscope design.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesWeber, Th. ; Giessen, H. ; Weckenbrock, M. ; Urbasch, G. ; Staudte, A. ; Spielberger, L. ; Jagutzki, O. ; Mergel, V. ; Vollmer, M. ; Dörner, R.
[s.l.] : Macmillian Magazines Ltd.
Published 2000Staff ViewISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Electronic correlations govern the dynamics of many phenomena in nature, such as chemical reactions and solid state effects, including superconductivity. Such correlation effects can be most clearly investigated in processes involving single atoms. In particular, the emission of two ...Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesBecker, U. ; Giessen, H. ; Zhou, F. ; Gilsdorf, T. ; Loidolt, J. ; Muller, M. ; Grun, M. ; Klingshirn, C.
Amsterdam : ElsevierStaff ViewISSN: 0022-0248Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyGeosciencesPhysicsType of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesStaff View
ISSN: 0022-0248Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyGeosciencesPhysicsType of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 0022-0248Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyGeosciencesPhysicsType of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesGiessen, H. ; Becker, U. ; Langbein, W. ; Bogdanov, S. ; Kalt, H. ; Grun, M. ; Klingshirn, C.
Amsterdam : ElsevierStaff ViewISSN: 0022-0248Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyGeosciencesPhysicsType of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 1741-0444Keywords: Analogue-digital conversion ; Data acquisition systems ; microprocessors ; Modems ; Telephone lineSource: Springer Online Journal Archives 1860-2000Topics: BiologyChemistry and PharmacologyMedicineType of Medium: Electronic ResourceURL: