Noncentrosymmetric Tetrel Pnictides RuSi4P4 and IrSi3P3: Nonlinear Optical Materials with Outstanding Laser Damage Threshold

Noncentrosymmetric (NCS) tetrel pnictides have recently generated interest as nonlinear optical (NLO) materials due to their second harmonic generation (SHG) activity and large laser damage threshold (LDT). Herein nonmetal-rich silicon phosphides RuSi₄P₄ and IrSi₃P₃ are synthesized and characterized. Their crystal structures are reinvestigated using single crystal X-ray diffraction and ²⁹Si and ³¹P magic angle spinning NMR. In agreement with previous report RuSi₄P₄ crystallizes in NCS space group P1, while IrSi₃P₃ is found to crystallize in NCS space group Cm, in contrast with the previously reported space group C2. A combination of DFT calculations and diffuse reflectance measurements reveals RuSi₄P₄ and IrSi₃P₃ to be wide bandgap (E_g) semiconductors, E_g = 1.9 and 1.8 eV, respectively. RuSi₄P₄ and IrSi₃P₃ outperform the current state-of-the-art infrared SHG material, AgGaS₂, both in SHG activity and laser inducer damage threshold. Due to the combination of high thermal stabilities (up to 1373 K), wide bandgaps (≈2 eV), NCS crystal structures, strong SHG responses, and large LDT values, RuSi₄P₄ and IrSi₃P₃ are promising candidates for longer wavelength NLO materials.     

Investigation into the Influence of Sodium Lignosulfonate,Anionic Surfactants,and Their Mixtures on the Copper Cementation Rate by Zinc

Russian Journal of Non-Ferrous Metals - This article is devoted to the influence of sodium lignosulfonate (SL), anionic surfactants (sodium dodecylsulfate (SDS), sodium dodecylbenzene sulfonate...     

Mechanochemical synthesis of the low-temperature (B20) phase of FeGe

We have investigated solid-state reactions in an equiatomic mixture of Fe and Ge powders during ball milling in a water-cooled high-energy mill under an argon atmosphere. The mechanical alloying products have been characterized by x-ray diffraction, Mössbauer spectroscopy, and calorimetry. The observed sequence of phase formation correlates with the thermodynamic properties of the iron germanides involved. The alloy prepared by ball milling for 2 h consists entirely of nanocrystallites (?15 nm) of the low-temperature, stable, cubic (B20) phase of FeGe.     

Ermittlung von Verfahrensgrenzen für das Fügen durch Knickbauchen anhand des Werkstoffes E235+N

Through a systematic approach and the consistent comparison of the results between experimental and numerical investigations, a deep understanding of the bulging mechanisms has been first developed. From these investigations process limitations were derived and presented in the form of a working diagram for the material E235+N. With regard to a wide industrial use of upset bulging as a joining technology, a technologically, productively as well as economically appropriate method could be developed and validated by means of practical and numerical experiments.     

Ion-Exchange Interaction of Glass-Forming Silicate Melts with Mixed Chloride Melts

The ion-exchange interaction of the sodium aluminosilicate and sodium galliumsilicate melts with a mixture of molten Li, Na, K, Rb, Cs, and Ba chlorides is studied. It is established that two alkaline silicate melts are characterized by negative deviations from the ideal behavior, and silicate melts containing alkaline and alkaline-earth cations are characterized by noticeable positive deviations from the ideal behavior.     

Diffusion formation of boride phases on the iron surface

The composition, structure, and size of a coating formed as a result of the interaction between iron and a sodium tetraborate melt with additions of boron and silicon carbides have been determined using electron-probe X-ray microanalysis, X-ray powder diffraction analysis, and optical microscopy. The main regularities of the diffusion in multiphase systems have been considered. The rate constants of the growth of the phases under investigation and the parameters relating the reaction rate to the diffusion and thermodynamic characteristics of the Fe-B system have been determined.     

Time resolution of a 6-gap resistive plate chamber with strip readout

A 6-gap glass resistive plate chamber with a strip readout was tested on the beam of the U-70 accelerator at the Institute for High Energy Physics. A time resolution of ∼45 ps was attained at an efficiency of >98%. The position resolution along a strip was estimated to be ∼1 cm.     

A parameterized model of heat storage by lake sediments

A model of seasonal heat storage by lake sediments is proposed oriented at applications in climate modeling and at lake parameterization in numerical weather prediction. The computational efficiency is achieved by reformulating of the heat transfer problem as a set of ordinary differential equations for evolution of the temperature wave inside the upper sediment layer. Arising temperature and depth scales completely replace the conductivity of the sediment in the heat transfer equation and can be easily achieved from the lake water temperature observations without any data on the sediment thermal properties. The method is proposed for the scales estimation from the inverse solution of the model equations in special case of the constant water-sediment heat flux in ice-covered lakes. The method is tested on data from sediments of Lake Krasnoye, North-Western Russia. The long-term (1961–2002) modeling of temperature in German lakes Müggelsee and Heiligensee with a coupled one-dimensional model of lake water column and sediments has demonstrated an appreciable effect of the sediment heat storage on near-bottom temperatures in both lakes. Thus, incorporation of the sediment layer into lake temperature models can essentially improve, at low computational costs, the model performance, especially for shallow lakes. In addition, a better forecast of near-bottom temperature evolution on climatic scales can provide a better understanding of the response of lake benthic communities to global warming.