TY - JOUR
A1 - Fiedler, Thomas M.
A1 - Orzada, Stephan
A1 - Flöser, Martina
A1 - Rietsch, Stefan H. G.
A1 - Quick, Harald H.
A1 - Ladd, Mark E.
A1 - Bitz, Andreas
T1 - Performance analysis of integrated RF microstrip transmit antenna arrays with high channel count for body imaging at 7 T
JF - NMR in Biomedicine
N2 - The aim of the current study was to investigate the performance of integrated RF
transmit arrays with high channel count consisting of meander microstrip antennas
for body imaging at 7 T and to optimize the position and number of transmit ele-
ments. RF simulations using multiring antenna arrays placed behind the bore liner
were performed for realistic exposure conditions for body imaging. Simulations were
performed for arrays with as few as eight elements and for arrays with high channel
counts of up to 48 elements. The B1+ field was evaluated regarding the degrees of
freedom for RF shimming in the abdomen. Worst-case specific absorption rate
(SARwc ), SAR overestimation in the matrix compression, the number of virtual obser-
vation points (VOPs) and SAR efficiency were evaluated. Constrained RF shimming
was performed in differently oriented regions of interest in the body, and the devia-
tion from a target B1+ field was evaluated. Results show that integrated multiring
arrays are able to generate homogeneous B1+ field distributions for large FOVs, espe-
cially for coronal/sagittal slices, and thus enable body imaging at 7 T with a clinical
workflow; however, a low duty cycle or a high SAR is required to achieve homoge-
neous B1+ distributions and to exploit the full potential. In conclusion, integrated
arrays allow for high element counts that have high degrees of freedom for the pulse
optimization but also produce high SARwc , which reduces the SAR accuracy in the
VOP compression for low-SAR protocols, leading to a potential reduction in array
performance. Smaller SAR overestimations can increase SAR accuracy, but lead to a
high number of VOPs, which increases the computational cost for VOP evaluation
and makes online SAR monitoring or pulse optimization challenging. Arrays with
interleaved rings showed the best results in the study.
KW - body imaging at UHF MRI
KW - integrated transmit coil arrays
KW - VOP compression
Y1 - 2021
U6 - https://doi.org/10.1002/nbm.4515
SN - 0952-3480 (ISSN)
SN - 1099-1492 (eISSN)
VL - 34
IS - 7
PB - Wiley
CY - Weinheim
ER -
TY - JOUR
A1 - Fiedler, Thomas M.
A1 - Orzada, Stephan
A1 - Flöser, Martina
A1 - Rietsch, Stefan H. G.
A1 - Schmidt, Simon
A1 - Stelter, Jonathan K.
A1 - Wittrich, Marco
A1 - Quick, Harald H.
A1 - Bitz, Andreas
A1 - Ladd, Mark E.
T1 - Performance and safety assessment of an integrated transmit array for body imaging at 7 T under consideration of specificabsorption rate, tissue temperature, and thermal dose
JF - NMR in Biomedicine
N2 - In this study, the performance of an integrated body-imaging array for 7 T with 32 radiofrequency (RF) channels under consideration of local specific absorption rate (SAR), tissue temperature, and thermal dose limits was evaluated and the imaging performance was compared with a clinical 3 T body coil.
Thirty-two transmit elements were placed in three rings between the bore liner and RF shield of the gradient coil. Slice-selective RF pulse optimizations for B1 shimming and spokes were performed for differently oriented slices in the body under consideration of realistic constraints for power and local SAR. To improve the B1+ homogeneity, safety assessments based on temperature and thermal dose were performed to possibly allow for higher input power for the pulse optimization than permissible with SAR limits.
The results showed that using two spokes, the 7 T array outperformed the 3 T birdcage in all the considered regions of interest. However, a significantly higher SAR or lower duty cycle at 7 T is necessary in some cases to achieve similar B1+ homogeneity as at 3 T. The homogeneity in up to 50 cm-long coronal slices can particularly benefit from the high RF shim performance provided by the 32 RF channels. The thermal dose approach increases the allowable input power and the corresponding local SAR, in one example up to 100 W/kg, without limiting the exposure time necessary for an MR examination.
In conclusion, the integrated antenna array at 7 T enables a clinical workflow for body imaging and comparable imaging performance to a conventional 3 T clinical body coil.
KW - body imaging at 7 T MRI
KW - thermal dose
KW - tissue temperature
KW - transmit antenna arrays
Y1 - 2022
U6 - https://doi.org/10.1002/nbm.4656
SN - 0952-3480 (Print)
SN - 1099-1492 (Online)
VL - 35
IS - 5
SP - 1
EP - 17
PB - Wiley
ER -
TY - JOUR
A1 - Foltz, Christian
A1 - Schneider, Nicole
A1 - Wolf, Martin R.
A1 - Kausch, Bernhard
A1 - Schlick, Christopher
A1 - Luczak, Holger
ED - Nagl, Manfred
T1 - Usability engineering
JF - Collaborative and distributed chemical engineering : from understanding to substantial design process support; results of the IMPROVE Project. - (Lecture notes in computer science ; 4970)
Y1 - 2008
SN - 978-3-540-70552-9
U6 - https://doi.org/10.1007/978-3-540-70552-9_21
SP - 527
EP - 554
PB - Springer
CY - Berlin
ER -
TY - JOUR
A1 - Franke, Helmut
A1 - Streckert, Joachim
A1 - Bitz, Andreas
A1 - Goeke, Johannes
A1 - Hansen, Volkert
A1 - Ringelstein, E. Bernd
A1 - Nattkämper, Heiner
A1 - Galle, Hans-Joachim
A1 - Stögbauer, Florian
T1 - Effects of Universal Mobile Telecommunications System (UMTS) electromagnetic fields on the blood-brain barrier in vitro
JF - Radiation Research
Y1 - 2005
U6 - https://doi.org/10.1667/RR3424.1
SN - 1938-5404
VL - 164
IS - 3
SP - 258
EP - 269
ER -
TY - JOUR
A1 - Frauenrath, Tobias
A1 - Fuchs, Katharina
A1 - Dieringer, Matthias A.
A1 - Özerdem, Celal
A1 - Patel, Nishan
A1 - Renz, Wolfgang
A1 - Greiser, Andreas
A1 - Elgeti, Thomas
A1 - Niendorf, Thoralf
T1 - Detailing the use of magnetohydrodynamic effects for synchronization of MRI with the cardiac cycle: A feasibility study
JF - Journal of Magnetic Resonance Imaging
N2 - Purpose:
To investigate the feasibility of using magnetohydrodynamic (MHD) effects for synchronization of magnetic resonance imaging (MRI) with the cardiac cycle.
Materials and Methods:
The MHD effect was scrutinized using a pulsatile flow phantom at B0 = 7.0 T. MHD effects were examined in vivo in healthy volunteers (n = 10) for B0 ranging from 0.05–7.0 T. Noncontrast-enhanced MR angiography (MRA) of the carotids was performed using a gated steady-state free-precession (SSFP) imaging technique in conjunction with electrocardiogram (ECG) and MHD synchronization.
Results:
The MHD potential correlates with flow velocities derived from phase contrast MRI. MHD voltages depend on the orientation between B0 and the flow of a conductive fluid. An increase in the interelectrode spacing along the flow increases the MHD potential. In vivo measurement of the MHD effect provides peak voltages of 1.5 mV for surface areas close to the common carotid artery at B0 = 7.0 T. Synchronization of MRI with the cardiac cycle using MHD triggering is feasible. MHD triggered MRA of the carotids at 3.0 T showed an overall image quality and richness of anatomic detail, which is comparable to ECG-triggered MRAs.
Conclusion:
This feasibility study demonstrates the use of MHD effects for synchronization of MR acquisitions with the cardiac cycle. J. Magn. Reson. Imaging 2012;36:364–372. © 2012 Wiley Periodicals, Inc.
Y1 - 2012
U6 - https://doi.org/10.1002/jmri.23634
SN - 1522-2586
VL - 36
IS - 2
SP - 364
EP - 372
PB - Wiley-Liss
CY - New York
ER -
TY - JOUR
A1 - Frauenrath, Tobias
A1 - Hezel, Fabian
A1 - Renz, Wolfgang
A1 - de Geyer d'Orth, Thibaut
A1 - Dieringer, Matthias
A1 - von Knobelsdorf-Brenkenhoff, Florian
A1 - Prothmann, Marcel
A1 - Schulz-Menger, Jeanette
A1 - Niendorf, Thoralf
T1 - Acoustic cardiac triggering: a practical solution for synchronization and gating of cardiovascular magnetic resonance at 7 Tesla
JF - Journal of Cardiovascular Magnetic Resonance
N2 - Background
To demonstrate the applicability of acoustic cardiac triggering (ACT) for imaging of the heart at ultrahigh magnetic fields (7.0 T) by comparing phonocardiogram, conventional vector electrocardiogram (ECG) and traditional pulse oximetry (POX) triggered 2D CINE acquisitions together with (i) a qualitative image quality analysis, (ii) an assessment of the left ventricular function parameter and (iii) an examination of trigger reliability and trigger detection variance derived from the signal waveforms.
Results
ECG was susceptible to severe distortions at 7.0 T. POX and ACT provided waveforms free of interferences from electromagnetic fields or from magneto-hydrodynamic effects. Frequent R-wave mis-registration occurred in ECG-triggered acquisitions with a failure rate of up to 30% resulting in cardiac motion induced artifacts. ACT and POX triggering produced images free of cardiac motion artefacts. ECG showed a severe jitter in the R-wave detection. POX also showed a trigger jitter of approximately Δt = 72 ms which is equivalent to two cardiac phases. ACT showed a jitter of approximately Δt = 5 ms only. ECG waveforms revealed a standard deviation for the cardiac trigger offset larger than that observed for ACT or POX waveforms.
Image quality assessment showed that ACT substantially improved image quality as compared to ECG (image quality score at end-diastole: ECG = 1.7 ± 0.5, ACT = 2.4 ± 0.5, p = 0.04) while the comparison between ECG vs. POX gated acquisitions showed no significant differences in image quality (image quality score: ECG = 1.7 ± 0.5, POX = 2.0 ± 0.5, p = 0.34).
Conclusions
The applicability of acoustic triggering for cardiac CINE imaging at 7.0 T was demonstrated. ACT's trigger reliability and fidelity are superior to that of ECG and POX. ACT promises to be beneficial for cardiovascular magnetic resonance at ultra-high field strengths including 7.0 T.
KW - Interval Time Series
KW - Image Quality Score
KW - Image Quality Assessment
KW - Sound Pressure Level
KW - Cardiovascular Magnetic Resonance
Y1 - 2010
U6 - https://doi.org/10.1186/1532-429X-12-67
SN - 1532-429X
VL - 12
IS - 1
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Frauenrath, Tobias
A1 - Niendorf, Thoralf
A1 - Kob, Malte
T1 - Acoustic method for synchronization of Magnetic Resonance Imaging (MRI)
JF - Acta Acustica
N2 - Magnetic Resonance Imaging (MRI) of moving organs requires synchronization with physiological motion or flow, which dictate the viable window for data acquisition. To meet this challenge, this study proposes an acoustic gating device (ACG) that employs acquisition and processing of acoustic signals for synchronization while providing MRI compatibility, immunity to interferences with electro-magnetic and acoustic fields and suitability for MRI at high magnetic field strengths. The applicability and robustness of the acoustic gating approach is examined in a pilot study, where it substitutes conventional ECG-gating for cardiovascular MR. The merits and limitations of the ACG approach are discussed. Implications for MR imaging in the presence of physiological motion are considered including synchronization with other structure- or motion borne sounds.
Y1 - 2008
U6 - https://doi.org/10.3813/AAA.918017
SN - 1861-9959
VL - 94
IS - 1
SP - 148
EP - 155
PB - Hirzel
CY - Stuttgart
ER -
TY - JOUR
A1 - Gligorevic, Snjezana
T1 - Joint channel estimation and equalisation of fast time-varying frequency-selective channels
JF - European transactions on telecommunications
Y1 - 2008
SN - 1541-8251; 2161-3915; 1120-3862; 1124-318X
VL - Vol. 19
IS - Iss. 1
SP - 1
EP - 13
ER -
TY - JOUR
A1 - Gligorevic, Snjezana
T1 - Airport surface propagation channel in the C-Band: measurements and modeling
JF - IEEE transactions on antennas and propagation
Y1 - 2013
SN - 0018-926x
VL - Vol. 61
IS - Iss. 9
SP - 4792
EP - 4802
PB - IEEE
CY - New York
ER -
TY - JOUR
A1 - Grande, Marion
A1 - Meffert, Elisabeth
A1 - Schoenberger, Eva
A1 - Jung, Stefanie
A1 - Frauenrath, Tobias
A1 - Huber, Walter
A1 - Hussmann, Katja
A1 - Moormann, Mareike
A1 - Heim, Stefan
T1 - From a concept to a word in a syntactically complete sentence: An fMRI study on spontaneous language production in an overt picture description task
JF - NeuroImage
N2 - Spontaneous language has rarely been subjected to neuroimaging studies. This study therefore introduces a newly developed method for the analysis of linguistic phenomena observed in continuous language production during fMRI.
Most neuroimaging studies investigating language have so far focussed on single word or — to a smaller extent — sentence processing, mostly due to methodological considerations. Natural language production, however, is far more than the mere combination of words to larger units. Therefore, the present study aimed at relating brain activation to linguistic phenomena like word-finding difficulties or syntactic completeness in a continuous language fMRI paradigm. A picture description task with special constraints was used to provoke hesitation phenomena and speech errors. The transcribed speech sample was segmented into events of one second and each event was assigned to one category of a complex schema especially developed for this purpose. The main results were: conceptual planning engages bilateral activation of the precuneus. Successful lexical retrieval is accompanied – particularly in comparison to unsolved word-finding difficulties – by the left middle and superior temporal gyrus. Syntactic completeness is reflected in activation of the left inferior frontal gyrus (IFG) (area 44). In sum, the method has proven to be useful for investigating the neural correlates of lexical and syntactic phenomena in an overt picture description task. This opens up new prospects for the analysis of spontaneous language production during fMRI.
Y1 - 2012
U6 - https://doi.org/10.1016/j.neuroimage.2012.03.087
SN - 1522-2586
VL - 61
IS - 3
SP - 702
EP - 714
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Gräßl, Andreas
A1 - Renz, Wolfgang
A1 - Hezel, Fabian
A1 - Dieringer, Matthias A.
A1 - Winter, Lukas
A1 - Özerdem, Celal
A1 - Rieger, Jan
A1 - Kellmann, Peter
A1 - Santoro, Davide
A1 - Lindel, Tomasz D.
A1 - Frauenrath, Tobias
A1 - Pfeiffer, Harald
A1 - Niendorf, Thoralf
T1 - Modular 32-channel transceiver coil array for cardiac MRI at 7.0T
JF - Magnetic Resonance in Medicine
N2 - Purpose
To design and evaluate a modular transceiver coil array with 32 independent channels for cardiac MRI at 7.0T.
Methods
The modular coil array comprises eight independent building blocks, each containing four transceiver loop elements. Numerical simulations were used for B1+ field homogenization and radiofrequency (RF) safety validation. RF characteristics were examined in a phantom study. The array's suitability for accelerated high spatial resolution two-dimensional (2D) FLASH CINE imaging of the heart was examined in a volunteer study.
Results
Transmission field adjustments and RF characteristics were found to be suitable for the volunteer study. The signal-to-noise intrinsic to 7.0T together with the coil performance afforded a spatial resolution of 1.1 × 1.1 × 2.5 mm3 for 2D CINE FLASH MRI, which is by a factor of 6 superior to standardized CINE protocols used in clinical practice at 1.5T. The 32-channel transceiver array supports one-dimensional acceleration factors of up to R = 4 without impairing image quality significantly.
Conclusion
The modular 32-channel transceiver cardiac array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0T.
Y1 - 2013
U6 - https://doi.org/10.1002/mrm.24903
SN - 1522-2594
VL - 72
IS - 1
SP - 276
EP - 290
PB - Wiley-Liss
CY - New York
ER -
TY - JOUR
A1 - Gspandl, Stephan
A1 - Pill, Ingo
A1 - Reip, Michael
A1 - Steinbauer, Gerald
A1 - Ferrein, Alexander
T1 - Belief Management for High-Level Robot Programs
JF - Proceedings of the Twenty-Second International Joint Conference on Artificial Intelligence [electronic resource] : Barcelona, Catalonia, Spain, 16 - 22 July 2011 / sponsored by International Joint Conferences on Artificial Intelligence (IJCAI) and the Association for the Advancement of Artificial Intelligence (AAAI). Ed. by Toby Walsh
Y1 - 2011
N1 - International Joint Conference on Artificial Intelligence ; (22 : ; 2011.07.16-22 : ; Barcelona, Spain) ; IJCAI ; (22 : ; 2011.07.16-22 : ; Barcelona, Spain)
SP - 900
EP - 905
ER -
TY - JOUR
A1 - Haag, S.
A1 - Zontar, D.
A1 - Schleupen, Josef
A1 - Müller, T.
A1 - Brecher, C.
T1 - Chain of refined perception in self-optimizing assembly of micro-optical systems
JF - Journal of sensors and sensor systems
N2 - Today, the assembly of laser systems requires a large share of manual operations due to its complexity regarding the optimal alignment of optics. Although the feasibility of automated alignment of laser optics has been shown in research labs, the development effort for the automation of assembly does not meet economic requirements – especially for low-volume laser production. This paper presents a model-based and sensor-integrated assembly execution approach for flexible assembly cells consisting of a macro-positioner covering a large workspace and a compact micromanipulator with camera attached to the positioner. In order to make full use of available models from computer-aided design (CAD) and optical simulation, sensor systems at different levels of accuracy are used for matching perceived information with model data. This approach is named "chain of refined perception", and it allows for automated planning of complex assembly tasks along all major phases of assembly such as collision-free path planning, part feeding, and active and passive alignment. The focus of the paper is put on the in-process image-based metrology and information extraction used for identifying and calibrating local coordinate systems as well as the exploitation of that information for a part feeding process for micro-optics. Results will be presented regarding the processes of automated calibration of the robot camera as well as the local coordinate systems of part feeding area and robot base.
Y1 - 2014
U6 - https://doi.org/10.5194/jsss-3-87-2014
SN - 2194-878X
VL - 3
IS - 1
SP - 87
EP - 95
PB - Copernicus Publ.
CY - Göttingen
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Loss mechanisms and domain stabilization in doped BaTiO₃
JF - Journal of Physics C: Solid State Physics
Y1 - 1978
SN - 0022-3719
U6 - https://doi.org/10.1088/0022-3719/11/15/031
VL - 11
IS - 15
SP - 3333
EP - 3344
PB - n.a.
CY - London
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Electrical properties of acceptor-doped BaTiO3 ceramic. Hagemann, H. J.
JF - Berichte der Deutschen Keramischen Gesellschaft. 55 (1978)
Y1 - 1978
SN - 0365-9542
SP - 353
EP - 355
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
T1 - Reduction of hysteresis losses of ferroelectric BaTiO3. Hagemann, H. J.
JF - Ferroelectrics. 22 (1978)
Y1 - 1978
SN - 0015-0193
SP - 743
EP - 743
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P. K.
A1 - Lade, H.
A1 - Leers, D.
T1 - Thermal properties of C/H-, C/H/O-, C/H/N- and C/H/X-grown polycrystalline CVD diamond. P. K. Bachmann, H. J. Hagemann, H. Lade, ...
JF - Diamond and Related Material. Vol 4. (1995), H. Issue 5-6
Y1 - 1995
N1 - abstract online:
SP - 820
EP - 826
PB - Elsevier Science
CY - New York, NY [u.a.]
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P. K.
A1 - Lade, H.
A1 - Leers, D.
T1 - Influence of the gas phase on diamond deposition and diamond properties. Bachmann, P. K.; Hagemann, H.J.; Lade, H.; Leers, D.; Picht, F.; Wiechert, D. U.
JF - Advanced materials '94 : proceedings of the NIRIM International Symposium on Advanced Materials '94, Tsukuba, Japan, March 13 - 17, 1994 / National Institute for Research in Inorganic Materials. Ed. by M. Kamo
Y1 - 1994
N1 - NIRIM International Symposium on Advanced Materials ; <1994, Tsukuba>
SP - 115
EP - 120
PB - International Communications Specialists, Inc.
CY - Tokyo
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P.K.
A1 - Lade, H.
A1 - Leers, D.
T1 - CVD Diamond Growth: Gas Compositions and Film Properties / P.K. Bachmann, H.J. Hagemann, H. Lade, D. Leers, D.U. Wiechert and H. Wilson
JF - Advanced materials '94 : proceedings of the NIRIM International Symposium on Advanced Materials '94, Tsukuba, Japan, March 13 - 17, 1994 / National Institute for Research in Inorganic Materials. Ed. by M. Kamo ...
Y1 - 1994
N1 - NIRIM International Symposium on Advanced Materials ; 1994 (Tsukuba) : 1994.03.13-17
SP - 115
EP - 120
PB - International Communications Specialists
CY - Tokyo
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Bachmann, P.K.
A1 - Lade, H.
A1 - Leers, D.
T1 - Diamond chemical vapor deposition: gas compositions and film properties / Bachmann, P.K.; Hagemann, H.-J.; Lade, H; Leers, D.; Picht, F.; Wiechert, D.U.; Wilson, H.
JF - Diamond, SiC and nitride wide bandgap semiconductors : symposium held April 4 - 8, 1994, San Francisco, California, U.S.A. / ed.: Calvin H. Carter, Jr. ...
Y1 - 1994
SN - 1-55899-239-1
N1 - Materials Research Society symposium proceedings ; 339
SP - 267
EP - 277
CY - Pittsburgh, Penn.
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Backhaus, U.
A1 - Goessner, S.
T1 - Collaborative eLearning Concepts for University Level Online Laboratory Courses in Engineering. U. Backhaus, S. Goessner, H. J. Hagemann
JF - Proceedings Online Educa Berlin: 8th International Conference on Technology Supported Learning & Training. 2002
Y1 - 2002
N1 - Online Educa <2002, Berlin>
SP - 62
EP - 66
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Breitschuh, S.
A1 - Graber, S.
A1 - Schmitz, Günter
T1 - Internet Laboratory Courses with Remote Access and Control of Real Measurements on Sensors and Electronic Components
JF - Mechatronics & Robotics 2004 : Aachen, Germany, September 13 - 15, 2004 / [APS - European Centre for Mechatronics]. P. Drews (ed.)
Y1 - 2004
SN - 3-938153-30-X
N1 - MechRob <2004, Aachen>
SP - 1280
EP - 1284
PB - Eysoldt
CY - Aachen
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Cassidy, Wiliam D.
T1 - Diamond growth rates and quality: dependence on gas phase cpmposition / William D. Cassidy [...], Hans-Jurgen Hagemann
JF - Diamond, SiC and nitride wide bandgap semiconductors : symposium held April 4 - 8, 1994, San Francisco, California, U.S.A. / ed.: Calvin H. Carter, Jr. ....
Y1 - 1994
SN - 1-55899-239-1
N1 - Materials Research Society symposium proceedings ; 339
SP - 285
EP - 291
CY - Pittsburgh, Penn. ,
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
T1 - PCVD hybrid technology for single mode fibres. Hagemann, H. J.; Geittner, P.
JF - Proceedings : papers presented at: the 8th Annual European Fibre Optic Communications and Local Area Networks Exposition
Y1 - 1990
N1 - EFOC LAN <8, 1990, München>
SP - 67
EP - 72
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Leers, D.
T1 - Intrinsic scattering and absorption losses of Ge- and F-doped optical fibres prepared by PCVD. Geittner, P.; Hagemann, H. J. ; Leers, D.
JF - Electronics letters : an intern. publication / The Institution of Electrical Engineers. 25 (1989), H. 7
Y1 - 1989
SN - 0013-5194
SP - 436
EP - 437
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Lydtin, H.
A1 - Warnier, J.
T1 - Hybrid technology for large SM-fiber preforms. Geittner, P.; Hagemann, H. J.; Lydtin, H.; Warnier, J.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 6 (1988), H. 10
Y1 - 1988
SN - 0733-8724
SP - 1451
EP - 1454
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Warnier, J.
A1 - Weling, F.
T1 - Reduction of geometric taper losses in the PCVD process. Geittner, P.; Hagemann, H. J.; Warnier, J.; Weling, F.; Wilson, H.
JF - Electronics letters : an intern. publication / The Institution of Electrical Engineers. 21 (1985), H. 13
Y1 - 1985
SN - 0013-5194
SP - 870
EP - 871
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Geittner, P.
A1 - Warnier, J.
A1 - Wilson, H.
T1 - PCVD at high deposition rates. Geittner, P.; Hagemann, H. J.; Warnier, J.; Wilson, H.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 4 (1986), H. 7
Y1 - 1986
SN - 0733-8724
SP - 818
EP - 822
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Gudat, W.
A1 - Kunz, C.
T1 - Photoabsorption of alloys of Al with transition metals V, Fe, Ni and Cu and Pr near the Al L₂,₃-edge
JF - Solid State Communications
N2 - 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.
Y1 - 1974
SN - 0038-1098
U6 - https://doi.org/10.1016/0038-1098(74)91165-X
VL - 15
IS - 3
SP - 655
EP - 658
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Gudat, W.
A1 - Kunz, C.
T1 - Optical constants from the far infrared to the X-ray region: Mg, Al, Cu, Ag, Au, Bi, C, and Al₂O₃
JF - Journal of the Optical Society of America (JOSA)
Y1 - 1975
SN - 0030-3941
U6 - https://doi.org/10.1364/JOSA.65.000742
VL - 65
IS - 6
SP - 742
EP - 744
PB - Optical Society of America
CY - New York
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Gudat, W.
A1 - Kunz, C.
T1 - Photoabsorption coefficient of alloys of Al with transition metals V, Fe, Ni and Cu and Pr from 30 to 150 eV photon energy
JF - Physica status solidi b
N2 - 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.
Y1 - 1976
SN - 0031-8957
U6 - https://doi.org/10.1002/pssb.2220740211
N1 - weitere ISSN 0370-1972
VL - 74
IS - 2
SP - 507
EP - 521
PB - Wiley-VCH
CY - Berlin
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Hennings, D.
T1 - Reversible Weight change of acceptor-doped BaTiO3. Hagemann, H. J.; Hennings, D.
JF - Journal of the American Ceramic Society. 64 (1981)
Y1 - 1981
SN - 0002-7820
SP - 590
EP - 594
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Hennings, D.
A1 - Wernicke, R.
T1 - Ceramic multilayer capacitors. Hagemann, H. J.; Hennings, D.; Wernicke, R.
JF - Philips' technical review / Philips' Gloeilampenfabrieken. Philips' Gloeilampenfabrieken . 41 (1984)
Y1 - 1984
SN - 0031-7926
SP - 89
EP - 98
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Hero, A.
A1 - Gonser, U.
T1 - The valence change of Fe in BaTiO3 studied by Mößbauer effect and gravimetry. Hagemann, H. J.; Hero, A.; Gonser, U.
JF - Physica Status Solidi (A) - Applied Research. 61 (1980)
Y1 - 1980
SN - 0031-8965
SP - 63
EP - 72
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Ihrig, H.
T1 - Valence change and phase stability of 3d-doped BaTiO3 annealed in oxygen and hydrogen. Hagemann, H. J.; Ihrig, H.
JF - Physical Review B.. 20 (1979), H. 9
Y1 - 1979
SN - 1095-3795
SP - 3871
EP - 3878
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Lade, H.
A1 - Warnier, J.
A1 - Wiechert, D. U.
T1 - The performance of Depressed-Cladding Single-Mode Fibres with Different b/a Ratios. Hagemann, H.-J.; Lade, H.; Warnier, J.; Wiechert, D. U.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 9 (1991), H. 6
Y1 - 1991
SN - 0733-8724
SP - 689
EP - 694
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - O´Bryan, H. M.
T1 - Grain boundary and surface segragation of Ba-Ti-O-Phases in rutile. O´Bryan, H. M.; Hagemann, H. J.
JF - Journal of the American Ceramic Society. 70 (1987)
Y1 - 1987
SN - 0002-7820
SP - 274
EP - 278
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Stumpe, R.
A1 - Wagner, D.
A1 - Bäuerle, D.
T1 - The influence of contact effects on the dielectric behavior of diffuse phase transitions. Stumpe, R.; Wagner, D.; Bäuerle, D.; Hagemann, H. J.
JF - Ferroelectrics : the international journal devoted to the theoretical, experimental, and applied aspects of ferroelectrics and related materials / Letters section. 4 (1985)
Y1 - 1985
SN - 0731-5171
SP - 143
EP - 147
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Ungelenk, J.
A1 - Wiechert, D. U.
T1 - Optical time domain reflectometry (OTDR) of diameter modulations in single-mode fibers. Hagemann, H. J.; Ungelenk, J.; Wiechert, D. U.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 8 (1990), H. 11
Y1 - 1990
SN - 0733-8724
SP - 1641
EP - 1645
ER -
TY - JOUR
A1 - Hagemann, Hans-Jürgen
A1 - Wiechert, D. U.
T1 - Measurements and calculations of the LP01 intensity of SM fibres far off the core. Hagemann, H.-J.; Wiechert, D. U.
JF - Journal of Lightwave Technology (J-LT) / Institute of Electrical and Electronics Engineers (IEEE). 10 (1992), H. 4
Y1 - 1992
SN - 0733-8724
SP - 407
EP - 412
ER -
TY - JOUR
A1 - Hamm, Laurits
A1 - Hartung, Frank
T1 - High Quality Visual Communication based on IMS
JF - Mobilkommunikation : Technologien und Anwendungen ; Vorträge der 16. ITG-Fachtagung vom 18. bis 19. Mai 2011 in Osnabrück / Veranst.: Informationstechnische Gesellschaft im VDE (ITG) ... Tagungsleitung: Ralf Tönjes. Programmkomitee/Hrsg.: Peter Roer
Y1 - 2011
SN - 978-3-8007-3352-1
N1 - ITG-Fachbericht ; 230 ; Fachtagung Mobilkommunikation <16, 2011, Osnabrück>
SP - 80
EP - 85
PB - VDE-Verl.
CY - Berlin
ER -
TY - JOUR
A1 - Hansen, Volkert W.
A1 - Bitz, Andreas
A1 - Streckert, Joachim R.
T1 - RF Exposure of Biological Systems in Radial Waveguides
JF - IEEE Transactions on Electromagnetic Compatibility
Y1 - 1999
U6 - https://doi.org/10.1109/15.809852
SN - 1558-187X
VL - 41
IS - 4
SP - 487
EP - 493
ER -
TY - JOUR
A1 - Hartung, Frank
T1 - Mobile DRM Introduction: The Need for Mobile DRM
JF - Digital Rights Management : Technological, Economic, Legal and Political Aspects / Becker, Eberhard [u.a.]
Y1 - 2003
N1 - Lecture Notes in Computer Science ; 2770
SP - 138
EP - 149
PB - Springer
CY - Berlin
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Baldo, N.
A1 - Horn, U.
A1 - Kampmann, M.
T1 - RTCP feedback based transmission rate control for 3G wireless multimedia streaming / Baldo, N. ; Horn, U. ; Kampmann, M. ; Hartung, F. ;
JF - 15th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2004. PIMRC 2004. Date:5-8 Sept. 2004 ; Vol. 3
Y1 - 2004
N1 - http://dx.doi.org/10.1109/PIMRC.2004.1368313
SP - 1817
EP - 1821
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Dondeti, L.
A1 - Castleford, F.
T1 - Multimedia Internet KEYing (MIKEY) General Extension Payload for Open Mobile Alliance BCAST LTKM/STKM Transport / Dondeti, L. ; Castleford, D. ; Hartung, F.
Y1 - 2007
SP - 1
EP - 7
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Girod, Bernd
T1 - Copyright protection in video delivery networks by watermarking of pre-compressed video / Hartung, Frank ; Girod, Bernd
JF - Multimedia Applications, Services and Techniques - EMAST ´97 : Second European Conference Milan, Italy, May 21-23, 1997 Proceedings / Fdida, Serge ; Morganti, Michele
Y1 - 1997
N1 - Lecture Notes in Computer Science ; 1242
SP - 423
EP - 436
PB - Springer
CY - Berlin
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Girod, Bernd
T1 - Statistical optimization of switched two-level quantizers with application to DPCM encoding of color video / Hartung, Frank ; Girod, Bernd
JF - IEEE International Conference on Acoustics, Speech, and Signal Processing, 1996. ICASSP-96. Conference Proceedings., 1996
Y1 - 1996
SN - 0-7803-3192-3
SP - 1974
EP - 1977
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Girod, Bernd
A1 - Horn, Uwe
T1 - Subband Image Coding / Girod, Bernd ; Hartung, Frank ; Horn, Uwe
JF - Subband and Wavelet Transforms: Design and Applications / ed. by Ali N. Akansu
Y1 - 1995
SN - 0792396456
SP - 213
EP - 250
PB - Kluwer
CY - Boston
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Horn, Uwe
A1 - Huschke, Jörg
A1 - Kampmann, Markus
T1 - MBMS—IP Multicast/Broadcast in 3G Networks / Hartung, Frank ; Horn, Uwe ; Huschke, Jörg ; Kampmann, Markus ; Lohmar, Thorsten
JF - International Journal of Digital Multimedia Broadcasting. 2009 (2009)
Y1 - 2009
SN - 1687-7586
N1 - Article ID 597848
SP - 1
EP - 25
ER -
TY - JOUR
A1 - Hartung, Frank
A1 - Horn, Uwe
A1 - Huschke, Jörg
A1 - Kampmann, Markus
T1 - Delivery of Broadcast Services in 3G Networks / Hartung, Frank ; Horn, Uwe ; Jörg Huschke ; Kampmann, Markus ; Lohmar, Thorsten ; Lundevall, Magnus
JF - IEEE Transactions on Broastcasting. 53 (2007), H. 1 Part: 2
Y1 - 2007
SN - 0018-9316
N1 - campusweit: http://dx.doi.org/10.1109/TBC.2007.891711
SP - 188
EP - 199
ER -