TY  - JOUR
A1  - Zastrow, Udo
A1  - Rieder, G.
T1  - Bracketing eigenvalues of an oscillating elastic body by integral equations
JF  - Bracketing of eigenfrequencies of continous structures : Euromech Colloquium, no. 112, Mátrafüred (Hungary), 21 - 23 February, 1979 / ed. by À. Bosznay
Y1  - 1980
SN  - 963-05-2625-5
N1  - Euromech Colloquium <112, 1979, Mátrafüred>
SP  - 421
EP  - 434
PB  - Akad. Kiadó
CY  - Budapest
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
A1  - Panagiotopoulos, P. D.
T1  - An integral "Equation" approach to the unilateral contact problem
JF  - ZAMM - Zeitschrift für angewandte Mathematik und Mechanik. 59 (1979), H. 8
Y1  - 1979
SN  - 1521-4001
SP  - 392
EP  - 393
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
A1  - Hackl, Klaus
T1  - On the existence, uniqueness and completeness of displacements and stress functions in linear elasticity  / Hackl, Klaus ; Zastrow, Udo
JF  - Journal of Elasticity. 19 (1988), H. 1
Y1  - 1988
SN  - 1573-2681
SP  - 3
EP  - 23
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
T1  - On the formulation of the fundamental solutions for orthotropic plane elasticity
JF  - Acta Mechanica. 57 (1985), H. 3-4
Y1  - 1985
SN  - 1619-6937
SP  - 113
EP  - 122
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
T1  - On the complete system of fundamental solutions for anisotropic slices and slabs: A comparison by use of the slab analogy
JF  - Journal of Elasticity. 15 (1985), H. 3
Y1  - 1985
SN  - 1573-2681
SP  - 293
EP  - 318
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
T1  - Basic geometrical singularities in plane-elasticity and plate-bending problems
JF  - International Journal of Solids and Structures. 21 (1985), H. 10
Y1  - 1985
SN  - 0020-7683
SP  - 1047
EP  - 1067
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
T1  - Numerical plane stress analysis by integral equations based on the singularity method
JF  - SM archives . 10 (1985)
Y1  - 1985
SN  - 0376-7426
SP  - 113
EP  - 128
ER  - 
TY  - JOUR
A1  - Zastrow, Udo
T1  - Solution of plane anisotropic elastostatical boundary value problems by singular integral equations
JF  - Acta Mechanica. 44 (1982), H. 1-2
Y1  - 1982
SN  - 1619-6937
SP  - 59
EP  - 71
ER  - 
TY  - JOUR
A1  - Yazdanbakhsh, Pedram
A1  - Solbach, Klaus
A1  - Bitz, Andreas
T1  - Variable power combiner for RF mode shimming in 7-T MR imaging
JF  - IEEE Transaction on Biomedical Engineering
N2  - This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers’ input signals. The power distribution at the output ports of the VPC is then fed into the “mode” ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17% to 60% and from 14% to 55% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.
Y1  - 2012
U6  - http://dx.doi.org/10.1109/TBME.2012.2205926
SN  - 1558-2531
VL  - 59
IS  - 9
SP  - 2549
EP  - 2557
PB  - IEEE
CY  - New York
ER  - 
TY  - JOUR
A1  - Wolf, Martin
A1  - Simon, S.
A1  - Schlick, Christopher
T1  - Qualitative and Quantitative Analysis of Cooperation / Wolf, M. ; Simon, S. ; Schlick, C.
JF  - Proceedings : May 26 - 29, 1998, Cannes (France) = Actes : 26 - 29 mai 1998 / INRIA, Institut National de Recherche en Informatique et en Automatique, Unité de recherche ... F. Darses ..., eds
Y1  - 1998
N1  - COOP ; Institut National de Recherche en Informatique et en Automatique ; Centre ; (Sophia Antipolis) ; International Conference on the Design of Cooperative Systems ; (3 ; 1998.05.26-29 ; Cannes) ; Conference Internationale sur la Conception de Systèmes Coopératifs ; (3 ; 1998.05.26-29 ; Cannes) ; COOP ; (3 ; 1998.05.26-29 ; Cannes)
SP  - 1
EP  - 5
PB  - -
CY  - Cannes
ER  -