Infrared Resonance Tuning of Nanoslit Antennas with Phase-Change Materials.

Phase-change materials (PCMs) have been established as prime candidates for nonvolatile resonance tuning of nanophotonic components based on a large optical contrast between their amorphous and crystalline states. Recently, the plasmonic PCM InSbTe was introduced, which can be switched from an amorphous dielectric state to a crystalline metallic one over the entire infrared spectral range. While locally switching the PCM around metallic nanorod antennas has already been demonstrated, similar tuning of inverse antenna structures (nanoslits) has not yet been investigated.

Evolution of Short-Range Order of Amorphous GeTe Upon Structural Relaxation Obtained by TEM Diffractometry and RMC Methods.

Glasses frequently reveal structural relaxation that leads to changes in their physical properties including enthalpy, specific volume, and resistivity. Analyzing the short-range order (SRO) obtained from electron diffraction by transmission electron microscopy (TEM) in combination with Reverse-Monte-Carlo (RMC) simulations is shown to provide information on the atomic arrangement. The technique elaborated here features several benefits including reliability, accessibility, and allows for obtaining detailed structural data quickly.

Fast crystallization below the glass transition temperature in hyperquenched systems.

Many phase change materials (PCMs) are found to crystallize without exhibiting a glass transition endotherm upon reheating. In this paper, we review experimental evidence revealing that these PCMs and likely other hyperquenched molecular and metallic systems can crystallize from the glassy state when reheated at a standard rate. Among these evidences, PCMs annealed below the glass transition temperature T exhibit slower crystallization kinetics despite an increase in the number of sub-critical nuclei that should promote the crystallization speed.

More than one way home - Student raters' impressions of interventions and group processes in mentalisation based group psychotherapy and group analytic psychotherapy.

In a study comparing mentalisation-based group therapy (MBT-G) and group analytic psychotherapy (GAP) in a day clinic, both group psychotherapy forms were found to be highly effective. But how did specific interventions and processes in both groups differ? The present article describes student raters impressions. Twelve psychology students listened to 100 audio recordings of 90 minutes group psychotherapy sessions of GAP and MBT-G.

Highly tunable β-relaxation enables the tailoring of crystallization in phase-change materials.

In glasses, secondary (β-) relaxations are the predominant source of atomic dynamics. Recently, they have been discovered in covalently bonded glasses, i.e.

Examination of a Structural Preference in Quaternary Alkali-Metal (A) Rare-Earth (R) Copper Tellurides by Combining Experimental and Quantum-chemical Means.

In the quest for materials addressing the grand challenges of the future, there is a critical need for a broad understanding of their electronic structures because the knowledge of the electronic structure of a given solid allows us to recognize its structural preferences and to rationalize its properties. As previous research on quaternary chalcogenides containing active metals (a group-I- or -II-element), early transition-metals, and late transition-metals indicated that such materials could pose as alluring systems in the developments of thermoelectrics, our impetus was stimulated to probe the suitability of tellurides belonging to the prolific ARCuTe-family. In doing so, we first used quantum-chemical techniques to explore the electronic and vibrational properties of representatives crystallizing with different ARCuTe structure types.

Far-Infrared Near-Field Optical Imaging and Kelvin Probe Force Microscopy of Laser-Crystallized and -Amorphized Phase Change Material GeSbTe.

Chalcogenide phase change materials reversibly switch between non-volatile states with vastly different optical properties, enabling novel active nanophotonic devices. However, a fundamental understanding of their laser-switching behavior is lacking and the resulting local optical properties are unclear at the nanoscale. Here, we combine infrared scattering-type scanning near-field optical microscopy (SNOM) and Kelvin probe force microscopy (KPFM) to investigate four states of laser-switched GeSbTe (as-deposited amorphous, crystallized, reamorphized, and recrystallized) with nanometer lateral resolution.

The potential of chemical bonding to design crystallization and vitrification kinetics.

Controlling a state of material between its crystalline and glassy phase has fostered many real-world applications. Nevertheless, design rules for crystallization and vitrification kinetics still lack predictive power. Here, we identify stoichiometry trends for these processes in phase change materials, i.

Uncovering β-relaxations in amorphous phase-change materials.

Relaxation processes are decisive for many physical properties of amorphous materials. For amorphous phase-change materials (PCMs) used in nonvolatile memories, relaxation processes are, however, difficult to characterize because of the lack of bulk samples. Here, instead of bulk samples, we use powder mechanical spectroscopy for powder samples to detect the prominent excess wings-a characteristic feature of β-relaxations-in a series of amorphous PCMs at temperatures below glass transitions.

Switching between Crystallization from the Glassy and the Undercooled Liquid Phase in Phase Change Material Ge Sb Te.

Controlling crystallization kinetics is key to overcome the temperature-time dilemma in phase change materials employed for data storage. While the amorphous phase must be preserved for more than 10 years at slightly above room temperature to ensure data integrity, it has to crystallize on a timescale of several nanoseconds following a moderate temperature increase to near 2/3 T to compete with other memory devices such as dynamic random access memory (DRAM). Here, a calorimetric demonstration that this striking variation in kinetics involves crystallization occurring either from the glassy or from the undercooled liquid state is provided.

Advanced Optical Programming of Individual Meta-Atoms Beyond the Effective Medium Approach.

Nanometer-thick active metasurfaces (MSs) based on phase-change materials (PCMs) enable compact photonic components, offering adjustable functionalities for the manipulation of light, such as polarization filtering, lensing, and beam steering. Commonly, they feature multiple operation states by switching the whole PCM fully between two states of drastically different optical properties. Intermediate states of the PCM are also exploited to obtain gradual resonance shifts, which are usually uniform over the whole MS and described by effective medium response.

Hyperthyroidism appearing as hyperemesis gravidarum.

Vomiting is a poorly recognized manifestation of hyperthyroidism. During pregnancy, this appearance can be indistinguishable from hyperemesis gravidarum. Two patients with intractable hyperemesis gravidarum were found to have hyperthyroidism.

Taurocholate is more potent than cholate in suppression of bile salt synthesis in the rat.

Synthesis of bile salts is regulated through negative feedback inhibition by bile salts returning to the liver. Individual bile salts have not been distinguished with regard to inhibitory potential. We assessed inhibition of bile salt synthesis by either cholate or its taurine conjugate in bile fistula rats.

The effect of hepatic blood flow on taurocholate extraction by the isolated perfused rat liver.

The effect of the rate of portal blood flow on the fractional extraction of the bile salt sodium taurocholate was studied in the isolated perfused rat liver. Thirty-two livers were perfused with a 60 microM solution of taurocholate at flow rates varying from 0.65 to 3.

Inhibition of human fat cell adenylate cyclase mediated via alpha-adrenoceptors.

Human adipose tissue contains alpha- as well as beta-adrenoceptor sites mediating antagonistic catecholamine effects on lipolysis. To characterize the mechanisms of catecholamine action in biochemical terms we have studied the effects of the almost pure beta-adrenoceptor agonist isoproterenol and of the mixed adrenergic agonist adrenaline on human fat cell adenylate cyclase in the presence of alpha- and beta-adrenoceptor blocking drugs. In contrast to the almost pure beta-adrenergic agent isoproterenol, the mixed agonist adrenaline, besides its stimulatory action, also had inhibitory effects which became apparent upon complete beta-adrenoceptor blockade using 0.

Hepatic extraction of bile salts in conscious dogs.

The enterohepatic circulation of cholic acid conjugates (CAC) was studied in three conscious dogs by comparing the relationship of the concentration of CAC in portal, hepatic, and peripheral venous plasma samples collected simultaneously. The pool of CAC in each dog was labeled with 14C. Catheters were surgically placed in the jugular, left hepatic, and portal veins.