Adsorption Properties of a Magnetite Composite with Coffee Waste

Russian Journal of Physical Chemistry A - Magnetic composite sorbent consisting of a synthetic magnetite and ground coffee waste is produced and characterized. The point of zero charge is...     

Probabilistic Study of Rainfall-Triggered Instabilities in Randomly Heterogeneous Unsaturated Finite Slopes

Transport in Porous Media - Water infiltration destabilises unsaturated soil slopes by reducing matric suction, which produces a decrease of material cohesion. If the porosity of the soil is...     

Constraint Reduction Reformulations for Projection Algorithms with Applications to Wavelet Construction

Journal of Optimization Theory and Applications - We introduce a reformulation technique that converts a many-set feasibility problem into an equivalent two-set problem. This technique involves...     

Experimental Calibration of Sn‐Related Varshni Parameters for High Sn Content GeSn Layers

From temperature‐dependent photoluminescence of a single Ge_0.84Sn_0.16 sample, Sn‐related Varshni parameters are extracted and used as input parameters in an 8‐band k·p model, and predict direct bandgap energies of high Sn content GeSn alloys with concentration varying from 8% to 16%. Then, exhaustively compared are the calculated direct Γ‐valley bandgap energies to photoluminescence results of 13% and 16% Sn content alloys and to direct bandgap energies found in literature. The agreement between k·p modeling and experimental datasets is close to 3% for different strain conditions of GeSn epilayers. The outcome of this study is an 8‐band k·p model with a fixed set of parameters, the model being self‐sufficient to describe the direct bandgap of Ge_1?xSn_x layers with x varying from 8% to 16% for large ranges of strain and temperature.     

Dopant effects on the structural, low temperature Raman scattering and electrical transport properties in SrTi1?xFexO3 nanoparticles synthesized by sol-gel method

We investigate effects of Fe dopant concentration on the structure, as well as low temperature Raman scattering and electrical transport properties in SrTi_1−x Fe _x O₃ (x = 0.00, 0.10, 0.20, 0.30, 0.40) nanoparticles prepared by sol-gel method. The results show an average particle size of powder is about 30 nm, and the lattice parameters decrease as increasing the Fe content. In the Raman spectra, a broad structure in the region 200–500 cm⁻¹ is almost absent and the peaks in the region 600–800 cm⁻¹ show different weights with respect to SrTiO₃, relating to structural changes with increasing dopant concentration in conjunction with increasing grain boundary contribution to the impedance. The abrupt change in Raman peak position as function of temperature suggests a phase transition in our samples in the range of 110–150 K. These results indicate that the Fe ion has replaced the site of Ti in unit cell. These results also demonstrate the feasibility of synthesizing the compound with low annealing temperature.     

Phosphaethyne polymers are analogues of cis-polyacetylene and graphane

Spontaneous and rapid polymerization of phosphaethyne was previously observed, however the crystal structure and electronic properties of the polymer have not been studied in detail. In the present work, we investigated the stability and electronic structure of the polymers based on phosphaethyne, which were studied using density functional methods and compared with those of the polymers of acetylene (cis-polyacetylene and graphane) and phosphorus (black phosphorus allotrope). Similar to the reference compounds, the graphane-like layer structure of poly-phosphaethyne is considerably more thermodynamically stable than the oligomers and has no unsaturated chemical bonds; hence it can be synthesized. This also opens the way to chemically modify and fine-tune the properties of graphane by synthetically incorporating poly-phosphaethyne units in the layer structure. We would propose that when using appropriate reaction conditions, graphane-like structures can be prepared by polymerization of phosphaethyne.     

Two new sesquiterpenes from Sarcandra glabra

Phytochemical study of the ethanol extract of Sarcandra glabra resulted in the isolation of two new sesquiterpenes, glabranols A (1) and B (2). Their structures were elucidated as 8alpha,9alpha,15-trihydroxylinden-4,7(11)-dien-12,8beta-olide (1) and 1beta,4alpha,7beta,11-tetrahydroxyeudesmane (2), by spectroscopic methods including 1D- and 2D-NMR and FTICR-MS.     

A new monoterpenoid glycoside from Myrica esculenta and the inhibition of angiotensin I-converting enzyme

One new monoterpenoid glycoside, myresculoside (1), and eleven known compounds, were isolated from methanol extract of Myrica esculenta leaves by repeated column chromatography. The effects of these compounds on angiotensin I-converting enzyme (ACE) inhibition were investigated. Compounds 3 and 4 showed the most potent ACE inhibition with rates of 29.97% and 25.63% at concentration of 100 μM, respectively. Compounds 5, 6, and 11 showed weak activity with inhibitory rates of 0.07-1.41% at concentration of 100 μM.