We study dynamically highly asymmetric binary mixtures comprised of small methyl tetrahydrofuran (MTHF) molecules and polystyrene. Combined use of dielectric spectroscopy, 2H nuclear magnetic resonance, incoherent quasielastic neutron scattering, and depolarized dynamic light scattering allows us to selectively probe the dynamics of the components in a broad dynamic range. It turns out that the mixtures exhibit two glass transitions in a wide concentration range although being fully miscible on a macroscopic scale. In between both glass transition temperatures, the dynamics of the small molecules show strong confinement effects, e.g., a crossover from Vogel-Fulcher to Arrhenius behavior of the time constants. Moreover, the dynamical behavior of small molecules close to the slow matrix is consistent with mode coupling theory predictions for a type-A glass transition, which was expected from recent theoretical and simulation studies in comparable systems.
Zur Repositions- und Implantatkontrolle wird häufig eine intraoperative 2D-Fluoroskopie durchgeführt. Diese liefert allerdings nicht immer die Details, um Gelenkstufen oder Fehlrepositionen sicher zu erkennen. Über die letzten Jahre hat sich die intraoperative 3D-Darstellung etabliert und weiterentwickelt. Multiple Studien belegen einen Vorteil und eine bessere intraoperative Kontrolle durch eine 3D-Darstellung. Beispiele hier sind neben der Wirbelsäule das obere Sprunggelenk, die proximale Tibia sowie der distale Radius; hier liegen die Raten der intraoperativen Revisionen bei durchgeführter digitaler Volumentomographie (DVT) zwischen 20–30 %. Technische Weiterentwicklungen, wie z. B. Metallartefaktreduktionen, automatisierte Ebeneneinstellung, automatische Schraubendetektion und robotisierte DVT-Geräte, erleichtern die intraoperative Bedienung, verkürzen die Operationszeit und bieten eine verbesserte Bildqualität. Durch Aufbereitung der Datensätze in Form eines immersiven, computersimulierten Bilds im Sinne der "augmented reality" (AR) kann intraoperativ eine erhöhte Präzision bei gleichzeitig verringerter Strahlenbelastung erzielt werden. Die Implementierung dieser Systeme ist mit Kosten verbunden, diesen stehen Kosteneinsparungen durch vermiedene Revisionen entgegen. Eine adäquate Gegenfinanzierung fehlt zum aktuellen Zeitpunkt noch. Die intraoperative 3D-Bildgebung stellt ein wichtiges Tool zur intraoperativen Kontrolle dar. Die aktuelle Datenlage erfordert, sich mit dem routinemäßigen Einsatz von 3D-Verfahren v. a. im Gelenkbereich auseinanderzusetzen. Die Indikationsstellung wird zunehmend weiter gefasst. Technische Neuerungen wie z. B. Robotik und AR haben in den letzten Jahren die 3D-Geräte deutlich verbessert und bieten ein hohes Potenzial zur Integration in den OP.
In recent years, due to the availability of affordable 3D sensors and the increased computing power, various methods for the generation of 3D thermograms have been developed. 3D thermal imaging describes the fusion of geometry and temperature data. A well-established approach is the fusion of data from depth and long-wave infrared (LWIR) cameras. However, these models generated in real-time have the limitation that the model size is limited due to inefficient data storage approach. Newer algorithms from Computer Vision promise to overcome this limitation by more efficient data handling and storage. Within this work, three state of the art 3D reconstruction algorithms from the computer vision community are compared and one of these is extended by overlaying thermal data, which allows the creation of large-scale 3D thermograms with a portable 3D measurement system. For this purpose, a geometric calibration is required, the data structure is adapted, and the handling of cyclic non-uniformity corrections required for uncooled LWIR cameras is described. The results will show exemplary 3D thermograms and the advantages compared to current existing systems.
In recent years, various methods for the generation of 3D thermograms have been developed.A well-stablished approach is the fusion of data from depth and long-wave infrared (LWIR) cameras.However, these models generated in real-time have the limitation that the model size is limited due to inefficient data storage.Newer algorithms from Computer Vision promise to overcome this limitation.Within this work, one of these 3D modelling algorithms is extended by the overlay of thermal data, which allows the creation of large-scale 3D thermograms.The results will show the advantages over current existing systems.
The structure of two model room temperature ionic liquids, [BMIM](+)[PF(6)](-) and [BMIM](+)[BF(4)](-), near the solid/liquid interface with charged Al(2)O(3)(0001) (sapphire) was determined with subnanometer resolution by high energy (72.5 keV) x-ray reflectivity. [BMIM](+)[PF(6)](-) exhibits alternately charged, exponentially decaying, near-surface layering. By contrast, the smaller-anion compound, [BMIM](+)[BF(4)](-), shows only a single layer of enhanced electron density at the interface. The different layering behaviors, and their characteristic length scales, correspond well to the different bulk diffraction patterns, also measured in this study. Complementary measurements of the surface and interface energies showed no significant different between the two RTILs. The combined bulk-interface results support the conclusion that the interfacial ordering is dominated by the same electrostatic ion-ion interactions dominating the bulk correlations, with hydrogen bonding and dispersion interactions playing only a minor role.
