81 research outputs found
Semiconductor Laser Engineering, Reliability and Diagnostics A Practical Approach to High Power and Single Mode Devices
No full textReliability and Diagnostics reflects the extensive expertise of the author in the diode laser field both as a top scientific researcher as well as a key developer of high-power highly reliable devices. With invaluable practical advice, this new reference book is suited to practising researchers in diode laser technologies, and to postgraduate engineering students. Dr. Peter W. Epperlein is Technology Consultant with his own semiconductor technology consulting business Pwe-PhotonicsElectronics-IssueResolution in the UK. He looks back at a thirty years career in cutting edge photonics and electronics industries with focus on emerging technologies, both in global and start-up companies, including IBM, Hewlett-Packard, Agilent Technologies, Philips/NXP, Essient Photonics and IBM/JDSU Laser Enterprise. He holds Pre-Dipl. (B.Sc.), Dipl. Phys. (M.Sc.) and Dr. rer. nat. (Ph.D.) degrees in physics, magna cum laude, from the University of Stuttgart, Germany. Dr. Epperlein is an internationally recognized expert in compound semiconductor and diode laser technologies. He has accomplished R&D in many device areas such as semiconductor lasers, LEDs, optical modulators, quantum well devices, resonant tunneling devices, FETs, and superconducting tunnel junctions and integrated circuits. His pioneering work on sophisticated diagnostic research has led to many world's first reports and has been adopted by other researchers in academia and industry. He authored more than seventy peer-reviewed journal papers, published more than ten invention disclosures in the IBM Technical Disclosure Bulletin, has served as reviewer of numerous proposals for publication in technical journals, and has won five IBM Research Division Awards. His key achievements include the design and fabrication of high-power, highly reliable, single mode diode lasers. Book Reviews "Semiconductor L
Pancreas development in zebrafish: early dispersed appearance of endocrine hormone expressing cells and their convergence to form the definitive islet.
No full textpeer reviewedTo begin to understand pancreas development and the control of endocrine lineage formation in zebrafish, we have examined the expression pattern of several genes shown to act in vertebrate pancreatic development: pdx-1, insulin (W. M. Milewski et al., 1998, Endocrinology 139, 1440-1449), glucagon, somatostatin (F. Argenton et al., 1999, Mech. Dev. 87, 217-221), islet-1 (Korzh et al., 1993, Development 118, 417-425), nkx2.2 (Barth and Wilson, 1995, Development 121, 1755-1768), and pax6.2 (Nornes et al., 1998, Mech. Dev. 77, 185-196). To determine the spatial relationship between the exocrine and the endocrine compartments, we have cloned the zebrafish trypsin gene, a digestive enzyme expressed in differentiated pancreatic exocrine cells. We found expression of all these genes in the developing pancreas throughout organogenesis. Endocrine cells first appear in a scattered fashion in two bilateral rows close to the midline during mid-somitogenesis and converge during late-somitogenesis to form a single islet dorsal to the nascent duodenum. We have examined development of the endocrine lineage in a number of previously described zebrafish mutations. Deletion of chordamesoderm in floating head (Xnot homolog) mutants reduces islet formation to small remnants, but does not delete the pancreas, indicating that notochord is involved in proper pancreas development, but not required for differentiation of pancreatic cell fates. In the absence of knypek gene function, which is involved in convergence movements, the bilateral endocrine primordia do not merge. Presence of trunk paraxial mesoderm also appears to be instrumental for convergence since the bilateral endocrine primordia do not merge in spadetail mutants. We discuss our findings on zebrafish pancreatogenesis in the light of evolution of the pancreas in chordates
The ReTrainer arm exoskeleton - a modular lightweight device that combines adjustable gravity compensation, lockable joints and neuromuscular electrical stimulation
No full text
Applications of laser-induced periodic surface structures (LIPSS)
No full textApplications of laser-induced periodic surface structures (LIPSS, ripples) upon irradiation of solid materials by fs-laser pulses are reviewed. This includes the colorization of technical surfaces, the control of surface wetting, the mimicry of the natural texture of animal integuments for realizing specific fluid transport functionalities, the tailoring of surface colonization by bacterial biofilms, and the improve-ment of the tribological performance of nanostructured metal surfaces
Transport in partially degenerate, magnetized plasmas. Part 2. Numerical calculation of transport coefficients
No full textThe modified Fokker–Planck collision operator for partially
degenerate electrons was derived in an earlier paper [J. Plasma Phys.58, 577 (1997)]. This is now employed to study linear
electron transport for a partially
degenerate, magnetized plasma. Because polynomial expansions can yield
incorrect transport coefficients owing to lack of resolution of the small fraction
of low-energy unmagnetized electrons, a numerical discrete-ordinate scheme is
employed. The inclusion of electron–electron collisions advances the model
beyond that of Lee and More, and in the classical limit agrees with the results
of Epperlein and Haines.</jats:p
O libovolně dlouhých periodických orbitech evolučních her na grafech
No full textPeriodické chování v biologických a ekonomických systémech je velmi sledovaným fenoménem. Ukážeme, že pro libovolné herně-teoretické parametry popisují sociální dilemata projevují evoluční hry na grafech s imitační dynamikou periodické chování. Zkonstruujeme grafy a jim odpovídající počáteční podmínky, jejichž trajektorie jsou periodické s libovolnou minimální periodou. Také prozkoumáme periodické chování evolčních her na grafu, jejichž graf je acyklický (strom). I tato acyklická struktura překvapivě umožňuje vznik libovolně dlouhých periodických orbitů.2019-06-30A periodic behavior is a well observed phenomena in biological and economical systems. We show that evolutionary games on graphs with imitation dynamics can display periodic behavior for an arbitrary choice of game theoretical parameters describing social-dilemma games. We construct graphs and corresponding initial conditions whose trajectories are periodic with an arbitrary minimal period length. We also examine a periodic behavior of evolutionary games on graphs with the underlying graph being an acyclic (tree) graph. Astonishingly, even this acyclic structure allows for arbitrary long periodic behavior
Separation of enantiomers of drugs by capillary electrophoresis; Part 8: β-Cyclodextrin as chiral solvating agent 毛细管电泳分离分析对映体药物 8. β-环糊精作手性选择剂
No full textElectronic Transport in Disordered Interacting Systems
No full textWe numerically investigate the transport properties of disordered interacting electrons in three dimensions in the metallic as well as in the insulating phases. The disordered many-particle problem is modeled by the quantum Coulomb glass which contains a random potential, long-range unscreened Coulomb interactions and quantum hopping between different sites. We have recently developed the Hartree-Fock based diagonalization (HFD) method which amounts to diagonalizing the Hamiltonian in a suitably chosen energetically truncated basis. This method allows us to investigate comparatively large systems. Here we calculate the combined effect of disorder and interactions on the dissipative conductance. We find that the qualitative influence of the interactions on the conductance depends on the relative disorder strength. For strong disorder interactions can significantly enhance the transport while they suppress the conductance for weak disorder
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