Reversible structural transition of two-dimensional copper selenide on Cu(111)

Structural engineering opens a door to manipulating the structures and thus tuning the properties of two-dimensional materials. Here, we report a reversible structural transition in honeycomb CuSe monolayer on Cu(111) through scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). Direct selenization of Cu(111) gives rise to the formation of honeycomb CuSe monolayers with 1D moiré structures (stripe-CuSe), due to the asymmetric lattice distortions in CuSe induced by the lattice mismatch. Additional deposition of Se combined with post annealing results in the formation of honeycomb CuSe with quasi-ordered arrays of triangular holes (hole-CuSe), namely, the structural transition from stripe-CuSe to hole-CuSe. Further, annealing the hole-CuSe at higher temperature leads to the reverse structural transition, namely from hole-CuSe to stripe-CuSe. AES measurement unravels the Se content change in the reversible structural transition. Therefore, both the Se coverage and annealing temperature play significant roles in the reversible structural transition in CuSe on Cu(111). Our work provides insights in understanding of the structural transitions in 2D materials.

Tin(IV) Compounds as Photo-Stabilizers for Irradiated Surfaces of Poly(Vinyl Chloride) Films

Dimethyl-organotin(IV) valsartan (Me2SnL2) and dichlorostannanediyl valsartan (SnL2Cl2) complexes were synthesized, characterized, and applied as Poly(vinyl chloride) (PVC) photo-stabilizers. The complexes were loaded within the PVC films in a weight ratio of 0.5%, and the modified films were irradiated to a UV light of 313 nm wavelength for 300 h at room temperature. The efficiency of the complexes-filled films was compared with the plain one and evaluated before and after irradiation by Fourier transform infrared spectroscopy, weight loss, gel content, change in viscosity, atomic force microscopy, and field emission scanning electron microscopy. The SnL2Cl2 complex had higher activity than the Me2SnL2 complex to retard the PVC’s photodegradation by several mechanisms.

Efficiency Comparison between Two Masonry Wall Drying Devices Using In Situ Data Measurements

In this paper, an in situ investigation and comparison of energy consumption and efficiency of two devices for implementation of the thermo-injection masonry wall drying method are presented. The following drying devices were considered: the currently used device (CUD) and the novel prototype device (NPD) with optimized control of the operating parameters. The historic building subjected to the drying and renovation was located in the city of Łowicz (Poland). The temperature and relative humidity of the air in several points in the basement and the temperature and moisture content at various locations in the considered masonry wall segments, as well as the electrical parameters for both devices, were measured in the real time and registered by applying a dedicated data acquisition system. The specific energy consumption during drying, defined as the energy consumption divided by the length of the drying wall section and by the mean volumetric moisture content change in the wall, was equal to 16.58 and 10.44 kWh/m/moisture content vol.% for the CUD and NPD, respectively. Moreover, the moisture content in the wall decreased by an average of 2.13 and 3.22 vol.% for the CUD and NPD, respectively, while the temperature of the wall surface in the drying zone was increased to approximately 35–40 °C and 40–65 °C for the CUD and NPD, respectively. The obtained results showed that the NPD was much more efficient than the CUD and that the building renovation process may be more environmentally friendly by applying more efficient drying devices and strategies.

Prediction of Dynamical Changes Hydrogen Sulfide Concentration During South-West Gissar Gas-Condensate Fields Development

An unexpected raise of hydrogen sulfide levels during development of several gas condensate fields in Southwestern Gissar, producing from naturally fractured carbonate reservoirs, observed within a year, lead to necessity of full scale comprehensive investigation. For planning of effective mitigation strategy important questions related to the reasons of hydrogen sulfide level growth and prediction of its further behavior have been addressed in the present study. The entire investigation process encompassed both theoretical and practical parts. Theoretical part covered evaluation of sour gas sources that was crucial in respect to selection of conceptual methodology for predictions. All possible contributing sources including primary and secondary have been investigated to discern the causes and consequences of hydrogen sulfide occurrence. Practical component of the study employed cut to edge technologies tested and implemented in reservoir simulation. Based on conceptual constraints with the use of existing field data, interpretation results and regional knowledge basin and 3D static models with fracture network have been developed. Obtained modeling results have been integrated into compositional model, allowing to predict with applied uncertainty analyses further H2S content change during field development.

Effect of Mn Substitution Fe on the Formability and Magnetic Properties of Amorphous Fe88Zr8B4 Alloy

Elemental substitution is commonly used to improve the formability of metallic glasses and the properties of amorphous alloys over a wide compositional range. Therefore, it is essential to investigate the influence of element content change on the formability as well as magnetic and other properties. The purpose is to achieve tailorable properties in these alloys with enhanced glass forming ability. In this work, the glass-forming ability (GFA) and magnetic properties of the minor Mn-substituted Fe88Zr8B4 amorphous alloy were investigated. The addition of Mn improving the amorphous forming ability of the alloy. With the addition of Mn, the magnetic transition temperature, saturation magnetization and the magnetic entropy changes (−ΔSm) peaks decreased simultaneously, which is possibly caused by the antiferromagnetic coupling between Fe and Mn atoms. The dependence of −ΔSmpeak on Tc displays a positive correlation compared to the −ΔSmpeak- Tc−2/3 relationship proposed by Belo et al.

Transcriptomic, Metabolomic, and Physiological Analyses Reveal That the Culture Temperatures Modulate the Cryotolerance and Embryogenicity of Developing Somatic Embryos in Picea glauca

Cryopreservation is one of the key technologies for the mass propagation of conifers via somatic embryogenesis. Cryotolerance and embryogenecity of conifer somatic embryos (SEs) could be affected by different temperature treatments, for which the underlying mechanisms were unknown. In this study, the developing SEs of Picea glauca obtained their cryotolerance with a survival rate of 100% when cultured on maturation medium at either 23°C for 4 weeks or 4°C for 10 weeks. However, only the embryos that underwent 4°C acclimation remained high embryogenicity, i.e., 91.7% based on cryovials or 29.3% on the plant tissue. Analysis of differentially expressed genes (DEGs) revealed that both 23 and 4°C treatments led to drastic changes in the gene expression, i.e., 21,621 and 14,906 genes, respectively, and the general increase in many oligosaccharides and flavonoids, in addition to the content change of proline (1.9- and 2.3-fold at 23 or 4°C) and gallic acid (6,963- and 22,053-fold). There were 249 significantly different metabolites between the samples of 23 and 4°C treatments and the changing trend of the sorbitol, fatty acids, and monosaccharides differed between these samples. During 4°C-acclimation, the metabolites of the arginine biosynthesis pathway increased between 2.4- and 8.1-fold, and the expression of antioxidant genes was up-regulated significantly. At 4°C, the up-regulated genes were for germ-like proteins, instead of seed storage proteins at 23°C. Concentrations of abscisic acid and jasmonic acid increased up to 2- and 1.5-fold, respectively, in the cold-acclimated embryos. After 10 weeks at 4°C, the embryos stayed at pre-cotyledonary stage with 17.1% less DNA methylation and fewer storage substances than those at 23°C for 4 weeks, which developed cotyledons. This research provides new insights into mechanisms underlying the response of SEs to different culture temperatures and benefits method development for germplasm conservation in conifers.