BINA

Halide perovskites (HaPs) have rapidly grown as highly promising photovoltaic materials. Despite the impressive device efficiencies, however, the fundamental mechanisms governing their unusual optoelectronic properties are still unclear [1]. In particular, the nature of their elementary optical excitations, their dynamics and interactions on ultrafast timescales are currently debated. Due to the comparatively low exciton binding energy, typically< 50 meV [2], the near-bandgap absorption in HaPs is a mixture of excitons and free carrier transitions. This makes it challenging to distinguish the contributions of these two species to the nonlinear optical spectra in experiments, in particular at room temperature.

We present combinatorial method for high-throughput screening and synthesis of libraries of solid lithium-ion conductors. The method has the advantages of speed, simplicity and the capability to produce and control simultaneously a variety of compositions by the co-deposition on a substrate of several different materials to create “materials library”. In our research we fabricate materials libraries by two methods. The first one is RF-magnetron sputtering, where Ar plasma sputters a target material that is being deposited on a substrate. The effects of RF power applied to Li2O and LiAlSiO2 targets, the deposition time, rotation of the substrate and heat treatment on Li-ion conductivity of 169 samples of one library have been studied. The XPS tests showed that RF coating contains Li2O, Li2CO3, LiAl0.18Si0.13O1.22, LiAl0.67Si0.41O2.49 and LiAl1.17Si0.71O3.93 compounds. The non-stoichiometric lithium …

Recently, we reported on a series of aminomethylene-phosphonate (AMP) analogues, bearing one or two heterocyclic groups on the aminomethylene moiety, as promising Zn (II) chelators. Given the strong Zn (II) binding properties of these compounds, they may find useful applications in metal chelation therapy. With a goal of inhibiting the devastating oxidative damage caused by prion protein in prion diseases, we explored the most promising ligand,{bis [(1H-imidazol-4-yl) methyl] amino} methylphosphonic acid, AMP-(Im) 2, 4, as an inhibitor of the oxidative reactivity associated with the Cu (II) complex of prion peptide fragment 84-114. Specifically, we first characterized the Cu (II) complex with AMP-(Im) 2 by ultraviolet-visible spectroscopy and electrochemical measurements that indicated the high chemical and electrochemical stability of the complex. Potentiometric pH titration provided evidence of the formation of a stable 1: 1 [Cu (II)-AMP-(Im) 2]+ complex (ML), with successive binding of a second AMP-(Im) 2 molecule yielding ML2 complex [Cu (II)-(AMP-(Im) 2) 2]+(log K'= 15.55), and log β'= 19.84 for ML2 complex. The CuN3O1 ML complex was demonstrated by X-ray crystallography, indicating the thermodynamically stable square pyramidal complex. Chelation of Cu (II) by 4 significantly reduced the oxidation potential of the former. CuCl2 and the 1: 2 Cu: AMP-(Im) 2 complex showed one-electron redox of Cu (II)/Cu (I) at 0.13 and-0.35 V, respectively. Indeed, 4 was found to be a potent antioxidant that at a 1: 1: 1 AMP-(Im) 2: Cu (II)-PrP84-114 molar ratio almost totally inhibited the oxidation reaction of 4-methylcatechol. Circular dichroism …

RF imaging technique based on optical time multiplexing super resolution methods is presented. The system overcome both resolution limits associated with antenna size and the number of detection channels whole incorporate target range detection.

Recently, we reported on a series of aminomethylene-phosphonate (AMP) analogues, bearing one or two heterocyclic groups on the aminomethylene moiety, as promising Zn(II) chelators. Given the strong Zn(II) binding properties of these compounds, they may find useful applications in metal chelation therapy. With a goal of inhibiting the devastating oxidative damage caused by prion protein in prion diseases, we explored the most promising ligand, {bis[(1H-imidazol-4-yl)methyl]amino}methylphosphonic acid, AMP-(Im)2, 4, as an inhibitor of the oxidative reactivity associated with the Cu(II) complex of prion peptide fragment 84–114. Specifically, we first characterized the Cu(II) complex with AMP-(Im)2 by ultraviolet–visible spectroscopy and electrochemical measurements that indicated the high chemical and electrochemical stability of the complex. Potentiometric pH titration provided evidence of the formation of a …

We propose to perform a spatial location finding of objects based upon using portable cellular devices. The data is derived from a set of time delayed signals observed by array of receiving elements having arbitrary and a priori known distribution in space. The popular solution of direction finding is based on time of arrival (TOA) measurement. The accuracy of the measurement depends strongly on different system and scenario parameters such as: target relative distance, number of elements, distances between the elements, azimuth and elevation beam widths which may cause ambiguity and multi path effects. For operational systems, it is important to have the ability to identify not only static targets but also moving ones. One of the modern solutions is time difference of arrival (TDOA) measurement. In addition to improve accuracy, we employ an advanced process, delta delta phase (DDPHASE) technique which is …

Lasers have become a generally accepted tool for surgery due to their advantages compared to traditional approaches like the scalpel. However, lasers lack a feedback system for safe laser guidance. This problem prevents the potential laser application for a lot of medical cases in the clinical environment. In this work, a new tissue differentiation modality which might be implemented as a feedback system using remote speckle-sensing is presented. This modality is tested on three tissue types and the results are discussed.

Hardware implementation of artificial neural networks facilitates real-time parallel processing of massive data sets. Optical neural networks offer low-volume 3D connectivity together with large bandwidth and minimal heat production in contrast to electronic implementation. In this presentation we will present a conceptual design for in-fiber optical neural network, i.e. a fiber-based realization of a photonic-FPGA. Neurons and synapses are realized in two ways: first as individual silica cores in a multi-core fiber and then within a multi-mode fiber. In the first realization optical signals are transferred transversely between cores by means of optical coupling. Pump driven amplification in erbium-doped cores mimics synaptic interactions. Simulations and experimental validation show classification and learning capabilities. Therefore, devices similar to our proposed multi-core fiber could potentially serve as building blocks …

Raman spectroscopy has been shown to be a powerful spectroscopic approach for detecting gases. It is capable of detecting gases that possess no infrared absorption feature, such as diatomics, and it also does not suffer from signal saturation as can be the case for transmission measurements. However, the Achilles heel of Raman based gas detection is the low scattering cross section. Here we show that introducing gas into an optical open micro-cavity (OMC) can greatly enhance the Raman signal. The enhancement comes from 2 factors: namely confining the light longer in the gas containing volume, hence strengthening the light-matter interaction, and also directing the Raman scattering in a more collimated fashion towards the detector. The OMC has been designed such that the separation between the mirrors is piezo controlled, hence it is possible to scan the micro-cavity resonances and tune the OMC to …

Planar acousto-optic devices are implemented in standard silicon on insulator. Pump light is absorbed in metallic gratings. Stimulated surface waves modulate an optical probe in a ring resonator. Narrowband microwave photonic filtering is demonstrated.

As the use of portable devices such as mobile phones, laptops and tablets grows rapidly, efficient portable energy technologies are becoming more necessary than ever. In the past years, fuel cells made a great advancement in the field of power sources technology, and are currently referred to as the most promising alternative energy technology. The most popular type of fuel cells today is the polymer electrolyte membrane fuel cell (PEMFC), fueled with hydrogen. Although it offers very high power density, the lack of fueling infrastructure necessary for the handling of hydrogen is currently one of its biggest commercial impediments. In order to overcome this hurdle with portable devices, direct methanol fuel cells (DMFC) were proposed as an alternative. This is mainly due to the methanol’s high energy density and ease of handling. DMFC’s were studied thoroughly over the past decades, and the technology …

We study induced transitions between different energy levels in the one-dimensional attractive Bose-Hubbard model with periodic boundary conditions. The initial eigenstates of the model are found by the exact diagonalization of the Bose-Hubbard Hamiltonian in the limit of small systems. Then, we drive transitions between the eigenstates by inducing a weak modulation of the tunnelling rate. The knowledge of exact eigenstates allows us to identify the selection rules for transitions between the different eigenstates. One obvious selection rule is related to the translation symmetry of the system. In addition, we identify a subspace in the total Hilbert space where parity symmetry dictates another and less obvious selection rule. We then show that in the strongly interacting limit this selection rule has implications on the entire Hilbert space. We discuss its signatures on the system's dynamics and consider how it can be …

Feshbach dimers and Efimov trimers, being insensitive to the short range inter-particle interactions, display a variety of universal properties. Standard experimental techniques for the study of Efimov physics have essentially been limited to the study of loss features due to inelastic collisions subject to variable initial conditions. Such an approach is best suited for the negative scattering length region, where the shallow trimer states dissociate into the free atom continuum. In contrast, for positive scattering lengths the presence of Feshbach dimers shifts the dissociation of trimers into the atom-dimer continuum and Efimov resonances remain inaccessible for direct observations. Here we develop a novel experimental approach which turns the presence of Feshbach dimers into an advantage. We use the dimers as a local reference for the Efimov trimers by creating a coherent superposition of both states. The …

A proper comparison between bond strengths of different atom pairs is relevant only for the same formal bond order (BO) of atomic interactions, e.g., for single bonds, because it is clear that the higher is the BO or the number of the electron pairs responsible of bonding, the stronger is the bond. For the metal–metal interactions, such a comparison of the bond strengths is especially problematic because formal BOs may differ from the effective ones by more than 1 v.u. (valence units). In this paper, we investigated the strength of bonding and its correlation to structural parameters (bond length/BO) for 24 metal-metal pairs. A simple way of the BO and bond-strength analysis was proposed and verified on the transition metal dimers. In contrast to the previous studies, the effective BOs were not calculated from spectroscopic data or related to reference compounds, but determined independently based on the Pauling model …

We empirically investigate agent software repositories using commonly used software metrics, which are used in software engineering literature to quantify meaningful characteristics of software based on its source code. We contrast the measurements with those of software in other categories. Analyzing hundreds of software projects, we nd that agent software may be di erent from other types of software, in terms of software complexity measures.