An effective route for the synthesis of cationic palladium complexes of general formula [(Acac)PdLL]A

A series of palladium complexes of general formula [(Acac)PdL¹L²]⁺A⁻, where L¹, L² = phosphines and A = BF₄, CF₃SO₃, were synthesized. Preliminary studies show that the complexes are active in selective dimerization of styrene and addition polymerization of norbornene.     

An analog to Kamenkov’s critical stability case for nonstationary systems of impulsive differential equations

A new approach to the investigation of the stability of nonlinear nonautonomous differential equations with impulse effects in critical cases is proposed. The approach is based on the direct method of Lyapunov with the use of piecewise differentiable functions. The sufficient conditions of the asymptotic stability of the critical position of equilibrium in one case are obtained. The case is analogous to Kamenkov’s critical case.     

Stability of silver clusters in mordenites with different SiO2/Al2O3 molar ratio

The stability and decay of silver clusters characterized by absorption bands 320 and 285 nm incorporated in mordenites with different SiO₂/Al₂O₃ molar ratios were studied under ambient conditions. Significantly different rates of disappearance of these two bands were the basis for assigning them to different silver species. Oxidation converts the clusters peaking at 320 and 285 nm into other silver clusters characterized by absorption bands at 310 and 240 nm, respectively. The oxidation of silver clusters peaking at 285 nm is significantly faster than that at 320 nm. The stability of both original clusters decreases with acid site strength that, in its turn, depends on Si0₂/Al₂O₃ molar ratio. The minimum lifetime of clusters peaking at 320 and 285 nm equal to ca. 40 and 20 days, respectively, was observed for mordenite characterized by the strongest acid sites. For mordenites possessing weaker acid sites, the lifetime of these clusters is found to be more than 50 months. The oxidation of silver clusters is reversible, and re-reduced silver clusters were revealed to possess the same electron structure as original ones.     

Real Matrix Representations for the Complex Quaternions

Starting from known results, due to Y. Tian in [5], referring to the real matrix representations of the real quaternions, in this paper we will investigate the left and right real matrix representations for the complex quaternions and we will give some examples in the special case of the complex Fibonacci quaternions.     

Spaceborne Laser Rangefinder “LORA” Used as a Cloud Lidar

First, in this report an overview is given on the use of the Russian laser altimeter in space “LORA” as a lidar for cloud measurements. Secondly, the influence of multiple scattering is verified by analysis of the backscatter signals from clouds having the excellent range resolution of a rangefinder.Presented at the 7th International Workshop on Multiple Scattering Lidar/Light Experiments (MUSCLE7), July 21–23 1994, Chiba, Japan.     

The relationship between the crystal structure and optical properties for isomeric aminopyridinium iodobismuthates

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A new synthetic route to substituted 1-fluoro-1-cyclopropanecarboxylates

Substituted 6-fluoro-2,4-dioxo-3-azabicyclo[3.1.0]hexane-6-carboxylates were obtained as a mixture of the exo- and endo-isomers by reaction of substituted 6,8-dioxo-2,3,7-triazabicyclo[3.3.0]oct-3-en-4-carboxylates with N-fluoropyridinium tetrafluoroborate.     

A New Look at the Spin Glass Problem from a Deep Learning Perspective

Spin glass is the simplest disordered system that preserves the full range of complex collective behavior of interacting frustrating elements. In the paper, we propose a novel approach for calculating the values of thermodynamic averages of the frustrated spin glass model using custom deep neural networks. The spin glass system was considered as a specific weighted graph whose spatial distribution of the edges values determines the fundamental characteristics of the system. Special neural network architectures that mimic the structure of spin lattices have been proposed, which has increased the speed of learning and the accuracy of the predictions compared to the basic solution of fully connected neural networks. At the same time, the use of trained neural networks can reduce simulation time by orders of magnitude compared to other classical methods. The validity of the results is confirmed by comparison with numerical simulation with the replica-exchange Monte Carlo method.     

Magnetization reversal by a single pulse of magnetic field or spin-polarized current

One of the important requirements for spintronic devices concerns an efficient magnetization reversal, which may eventually lead to ultra-fast non-volatile magnetic memory applications. In particular, it is necessary to achieve stable sub-nanosecond switching times and to reduce magnetization “ringing”, so that the reversal will proceed along the shortest ballistic path connecting the initial and the target magnetization states. This paper is dedicated to the numerical simulations of a mono-domain ferromagnetic particle, described by the Landau–Lifshitz–Gilbert equation. We study the general case of arbitrary orientation of the applied field/current pulses, constructing dynamic diagrams for the reversal time. We have found that even short 50 ps pulses, applied at a proper angle, will induce magnetization reversal with minimal ringing effects.