Level Crossing in a Frequency-dependent Photon Reservoir

Abstract

The level-crossing effect for a three-level atom placed into the resonant cavity (waveguide) and illuminated by a strong monochromatic laser light is discussed. The cavity plays the role of a frequency-dependent photon reservoir that modifies the spontaneous decay of the atom. The effect is studied by considering the modifications of the level-crossing (Hanle effect) signals. The non-Markovian character of spontaneous emission in frequency-dependent reservoirs is taken into account. Calculated signals are interpreted in terms of a dressed atom picture.     

Wetting and Microstructure Evolution of the Sn-Zn-Ag/Cu Interface

Wetting of Cu substrates by Sn-Zn eutectic-based alloys with 0.5, 1, and 1.5 wt.% of Ag was studied. Wetting tests were performed at 523 K, in the presence of ALU33^® flux, for 15, 30 and 60 s, respectively. The results indicated that the content of Ag in the alloys does not have significant effect on the contact angle. Selected, solidified Sn-8.8Zn-xAg/Cu couples were cross-sectioned and subjected to SEM-EDS study of the interfacial microstructure. The results revealed that the microstructure of the Sn-Zn-Ag/Cu interface evolves with time and is different from Sn-Zn/Cu interface. The continuous interlayers are observed at the interface. Composition of the interlayers was analyzed with EDS and their thickness measured.     

Unusual Solidification Behavior of the Suction-Cast Cu-Zr-Al-Y Alloy Doped with Fe

The effect of iron addition on the microstructure of the Cu-Zr-Al-Y glass-forming alloy was studied. Despite a high superficial cooling rate, small Fe additions (1.5 and 3 pct) induced formation of crystalline CuZr and AlCu₂Zr phases on the outer layers of suction-cast rods. As the melt composition near the solid/liquid interface was depleted in Fe, the remaining melt vitrified at a relatively low cooling rate.     

A cross-linked conjugated metallopolymer comprised of bisaxially coordinated ruthenium tetra-t-butyl phthalocyanine connected by quaterthiophene linkers

A ruthenium tetra-t-butylphthalocyanine bisaxially ligated with 3,5-bis(2,2′-bithiophene-5-yl)pyridine was synthesized from ruthenium tetra-t-butylphthalocyanine dimer. The complex was electropolymerized (in CH₂Cl₂ and CH₃CN, with and without addition of BF₃·Et₂O) to yield an insoluble conjugated metallopolymer, which was characterized by cyclic voltammetry and UV–vis spectroelectrochemistry. The polymer combines the electrochemical and spectral properties of the phthalocyanine and of a polythiophene-type conjugated polymer. In the presence of BF₃, the polymer can be reversibly p-doped and de-doped. Materials obtained in CH₂Cl₂ (tested in the same solvent) and in CH₃CN/BF₃ (tested in CH₃CN) exhibit an unusual hysteresis of redox properties.     

Modelling of a’fortiori reasoning

The paper presents the model of two variants of a’fortiori reasoning applicable in the case of statutory law as well the example of the genuine law case, which has been modeled with use of established methodology. The model of reasoning assumes the existence of “less–more” relation between the analyzed actions, which has been expressed by means of strict partial order and some additional assumptions. The paper also contains the implementation of the analyzed example.     

Membrane theory treatment of eccentric flows in concentric hoppers

This paper presents an initial study of the effects of an accidental eccentric flow channel that sometimes develops in the conical hopper of a metal storage silo. A simple assumed pressure regime is adopted, based on studies of eccentric discharge in cylindrical silos, and the structural actions are analysed using shell membrane theory. The results are verified against a finite element analysis. A set of equations is derived which give the complete membrane stress state in the hopper under such an unsymmetrical pressure regime.     

Lightweight PIM—a new multicast routing protocol

Multicast holds out great promise to significantly reduce network load between the sender and a group of receivers by delivering a single data stream to many recipients. Protocol‐Independent Multicast (PIM) Sparse Mode and its variant PIM Source‐Specific Multicast (PIM SSM) are the most widely used IP multicast protocols. Protocols offer low latency data delivery capabilities with relatively high reliability and are characterized by large signaling overhead. This article presents a new multicast protocol, called Lightweight PIM (LPIM), tackling the main problem hindering widespread usage of IP multicast protocols, which is a large volume of signaling traffic. Given the existing usability of the PIM family protocols, a decision was made to base the new LPIM protocol on PIM SSM. The improvements used in LPIM lead to a considerable reduction of state data and signaling messages required by LPIM as compared with PIM SSM. Similar to its predecessor, LPIM is capable of handling large groups, although with significantly lower overhead. Copyright © 2012 John Wiley & Sons, Ltd.     

In Situ Probing of Ion Ordering at an Electrified Ionic Liquid/Au Interface

Charge transport at the interface of electrodes and ionic liquids is critical for the use of the latter as electrolytes. A room‐temperature ionic liquid, 1‐ethyl‐2,3‐dimethylimidazolium bis(trifluoromethanesulfonyl)imide (EMMIM TFSI), is investigated in situ under applied bias voltage with a novel method using low‐energy electron and photoemission electron microscopy. Changes in photoelectron yield as a function of bias applied to electrodes provide a direct measure of the dynamics of ion reconfiguration and electrostatic responses of the EMMIM TFSI. Long‐range and correlated ionic reconfigurations that occur near the electrodes are found to be a function of temperature and thickness, which, in turn, relate to ionic mobility and different configurations for out‐of‐plane ordering near the electrode interfaces, with a critical transition in ion mobility for films thicker than three monolayers.     

Study of a new resin-based composites containing hydroxyapatite filler using Raman and infrared spectroscopy

The degree of conversion of polymeric matrix in hydroxyapatite-containing dental fillings by Raman and infrared spectroscopy has been determined. Resin-based dental composites are one of the most popular filling materials used in dentistry. These light-cured materials are characterized by the value of the degree of conversion, which depends on curing time and influences the quality of obtained dental filling. Distribution of the filler into polymeric matrix, which has a significant impact on the properties of the final product, has been determined by Raman mapping. The applied procedure also has allowed to present the changes of the degree of conversion on the examined surfaces. The results of the study demonstrate the versatility of the Raman spectroscopy as the analytical spectroscopic technique for determining chemical properties of dental fillings and providing insight into their organization at the microstructural level. The obtained degree of conversion values have been compared with data for the commercially available dental fillings characterized by other authors.     

Low power current-mode binary-tree asynchronous Min/Max circuit

A novel, current-mode, binary-tree, asynchronous Min/Max circuit for application in nonlinear filters as well as in analog artificial neural networks is proposed. The relatively high precision above 99% can be achieved by eliminating the copying of the input signals from one layer to the other in the tree. In the proposed solution, the input signals are always directly copied to particular layers using separate signal paths. This makes the precision almost independent on the number of the layers i.e. the number of the inputs. The circuit is a flexible solution. The power dissipation, as well as data rate can be scaled up and down in a wide range. For an average value of the input currents of 20 μA and data rate of 11 MHz the circuit dissipates 505 μW, while for the signals of 200 nA and data rate of 500 kHz the power dissipation is reduced to 1 μW. The prototype circuit with four inputs, realized in the CMOS 0.18 μm technology, occupies the area of 1800 μm².