@article{YazdanbakhshSolbachBitz2012, author = {Yazdanbakhsh, Pedram and Solbach, Klaus and Bitz, Andreas}, title = {Variable power combiner for RF mode shimming in 7-T MR imaging}, series = {IEEE Transaction on Biomedical Engineering}, volume = {59}, journal = {IEEE Transaction on Biomedical Engineering}, number = {9}, publisher = {IEEE}, address = {New York}, issn = {1558-2531}, doi = {10.1109/TBME.2012.2205926}, pages = {2549 -- 2557}, year = {2012}, abstract = {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.}, language = {en} } @article{YangKriechbaumerAlbrachtetal.2015, author = {Yang, Peng-Fei and Kriechbaumer, Andreas and Albracht, Kirsten and Sanno, Maximilian and Ganse, Bergita and Koy, Timmo and Shang, Peng and Br{\"u}ggemann, Gert-Peter and M{\"u}ller, Lars Peter and Rittweger, J{\"o}rn}, title = {On the relationship between tibia torsional deformation and regional muscle contractions in habitual human exercises in vivo}, series = {Journal of Biomechanics}, volume = {48}, journal = {Journal of Biomechanics}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2014.12.031}, pages = {456 -- 464}, year = {2015}, language = {en} } @article{YangKriechbaumerAlbrachtetal.2014, author = {Yang, Peng-Fei and Kriechbaumer, Andreas and Albracht, Kirsten and Sanno, Maximilian and Ganse, Bergita and Koy, Timmo and Shang, Peng and br{\"u}ggemann, Gert-Peter and M{\"u}ller, Lars Peter and Rittweger, J{\"o}rn}, title = {A novel optical approach for assessing in vivo bone segment deformation and its application in muscle-bone relationship studies in humans}, series = {Journal of Orthopaedic Translation}, volume = {2}, journal = {Journal of Orthopaedic Translation}, number = {4}, publisher = {Elsevier}, address = {Singapore}, issn = {2214-0328}, doi = {10.1016/j.jot.2014.07.078}, pages = {238 -- 238}, year = {2014}, language = {en} } @inproceedings{YanStreseChwallek2018, author = {Yan, Zexiong and Strese, Steffen and Chwallek, Constanze}, title = {Explorer CEOs: The effect of CEO career variety on large firms' relative exploration orientation}, series = {G-Forum Jahreskonferenz 2018}, booktitle = {G-Forum Jahreskonferenz 2018}, pages = {42 Seiten}, year = {2018}, abstract = {Prior studies demonstrate that firms need to make smart trade-off decisions between exploration and exploitation activities in order to increase performance. Chief executive officers (CEOs) are principal decision makers of a firm's strategic posture. In this study, we theorize and empirically examine how relative exploration orientation of large publicly listed firms varies based on the career variety of their CEOs - that is, how diverse the professional experiences of executives were prior to them becoming CEOs. We further argue that the heterogeneity and structure of the top management team moderates the impact of CEO career variety on firms' relative exploration orientation. Based on multisource secondary data for 318 S\&P 500 firms from 2005 to 2015, we find that CEO career variety is positively associated with relative exploration orientation. Interestingly, CEOs with high career varieties appear to be less effective in pursuing exploration, when they work with highly heterogeneous and structurally interdependent top management teams.}, language = {en} } @inproceedings{XuSchwarteHeinoletal.1998, author = {Xu, Zhanping and Schwarte, Rudolf and Heinol, Horst-Guenther and Buxbaum, Bernd and Ringbeck, Thorsten}, title = {Smart pixel : photonic mixer device (PMD) ; new system concept of a 3D-imaging camera-on-a-chip}, series = {Proceedings : M2VIP '98; Nanjing, China, 10th - 12th September 1998}, booktitle = {Proceedings : M2VIP '98; Nanjing, China, 10th - 12th September 1998}, editor = {Cheung, Edmund H. M.}, address = {Hong Kong}, isbn = {962-442-129-3}, pages = {259 -- 264}, year = {1998}, language = {en} } @article{XuLueMaetal.2005, author = {Xu, Jung-Ming and L{\"u}, Min and Ma, Meijie and Hellwig, Angelika}, title = {Super connectivity of line graphs}, series = {Information processing letters}, volume = {Vol. 94}, journal = {Information processing letters}, number = {Iss. 4}, issn = {1872-6119 (E-Journal); 0020-0190 (Print)}, pages = {191 -- 195}, year = {2005}, language = {en} } @book{Waehlisch2012, author = {W{\"a}hlisch, Georg}, title = {Technisches Zeichnen : L{\"o}sungsvorschl{\"a}ge f{\"u}r das Selbststudium. (Berichte aus dem Maschinenbau)}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8440-1159-3}, pages = {[138] S. : zahlr. Ill., graph. Darst.}, year = {2012}, language = {de} } @book{Waehlisch2009, author = {W{\"a}hlisch, Georg}, title = {Technisches Zeichnen : Vorlesung und {\"U}bungen}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8322-8044-4}, pages = {IV, 120, 80 S. : Ill., graph. Darst.}, year = {2009}, language = {de} } @inproceedings{WuttkeButenwegRosinetal.2019, author = {Wuttke, Claudia and Butenweg, Christoph and Rosin, Julia and Kubalski, Thomas}, title = {Verbesserte seismische Nachweiskonzepte f{\"u}r Mauerwerksbauten in deutschen Erdbebengebieten}, series = {Adam, Christoph (Hrsg.) ; Univ. Innsbruck: 16. D-A-CH Tagung Erdbebeningenieurwesen \& Baudynamik 2019 : 26. und 27. September 2019, Innsbruck}, booktitle = {Adam, Christoph (Hrsg.) ; Univ. Innsbruck: 16. D-A-CH Tagung Erdbebeningenieurwesen \& Baudynamik 2019 : 26. und 27. September 2019, Innsbruck}, address = {Innsbruck}, isbn = {978-3-200-06454-6}, pages = {713 -- 722}, year = {2019}, language = {de} } @inproceedings{WulfhorstMerseburgTippkoetter2015, author = {Wulfhorst, Helene and Merseburg, Johannes and Tippk{\"o}tter, Nils}, title = {Analyse von Lignocellulose mittels dynamischer Differenzkalorimetrie und Infrarot - Spektrometrie}, series = {12. Dresdner Sensor-Symposium 2015 2015-12-07 - 2015-12-09}, booktitle = {12. Dresdner Sensor-Symposium 2015 2015-12-07 - 2015-12-09}, isbn = {978-3-9813484-9-1}, doi = {10.5162/12dss2015/P6.2}, pages = {210 -- 215}, year = {2015}, language = {de} }