Cutting wood specimens for observation in the scanning electron microscope

This report deals with the cutting of wood specimens for observation in the scanning electron microscope. Several cutting devices and types of knives are described and critically evaluated.     

The control of graphene double-layer formation in copper-catalyzed chemical vapor deposition

The growth of graphene during Cu-catalyzed chemical vapor deposition was studied using ¹²CH₄ and ¹³CH₄ precursor gasses. We suggest that the growth begins by the formation of a multilayer cluster. This seed increases its size but the growth speed of a particular layer depends on its proximity to the copper surface. The layer closest to the substrate grows fastest and thus further limits the growth rate of the upper layers. Nevertheless, the growth of the upper layers continues until the copper surface is completely blocked. It is shown that the upper layers can be removed by modification of the conditions of the growth by hydrogen etching.     

Biosynthesis of Colabomycin E,a New Manumycin‐Family Metabolite,Involves an Unusual Chain‐Length Factor

Colabomycin E is a new member of the manumycin‐type metabolites produced by the strain Streptomyces aureus SOK1/5‐04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans. Bioinformatic analysis and mutagenic studies identified components of the biosynthetic pathway that are involved in the formation of both polyketide chains. Recombinant polyketide synthases (PKSs) assembled from the components of colabomycin E and asukamycin biosynthetic routes catalyzing the biosynthesis of “lower” carbon chains were constructed and expressed in S. aureus SOK1/5‐04 ΔcolC11–14 deletion mutant. Analysis of the metabolites produced by recombinant strains provided evidence that in both biosynthetic pathways the length of the lower carbon chain is controlled by an unusual chain‐length factor supporting biosynthesis either of a triketide in asukamycin or of a tetraketide in colabomycin E. Biological activity assays indicated that colabomycin E significantly inhibited IL‐1β release from THP‐1 cells and might thus potentially act as an anti‐inflammatory agent.     

Revealed comparative advantages in academic publishing of “old” and “new” European Union Member States 1998–2018

Scientometrics - The paper uses a variant of the Revealed Comparative Advantage index to examine comparative advantages of the European Union (EU) countries in 254 research areas and their...     

LiNi1/3Mn1/3Co1/3O2 with morphology optimized for novel concept of 3D Li accumulator

An array of LiNi_1/3Mn_1/3Co_1/3O₂ (NMC 111) samples with a hollow-sphere morphology enabling the use of binder-free, millimeter-thick electrodes in a battery are prepared by a combination of ball milling, hydrothermal treatment and calcination. Materials are studied by powder X-ray diffraction, nitrogen adsorption measurements, X-ray fluorescence analysis, and scanning electron microscopy. Their electrochemical performance for Li⁺ extraction/insertion is tested by cyclic voltammetry and galvanostatic chronopotentiometry on thin-film electrodes. Optimized materials, prepared by mechanical and thermal treatment with surface areas of 7 to 10 m² g⁻¹, provide charge capacity values of 141 to 156 mAh g⁻¹. The concentration of the crystalline phase in NMC 111 materials with a hollow-sphere morphology is found to be the decisive parameter for their galvanostatic cycling stability. Hollow spheres with well-developed NMC nanocrystals and a low concentration of amorphous phase in the walls, exhibiting excellent cycling stability and charge capacity in thin-film electrodes are incorporated into a NMC/graphite 3D-battery module. This 122 Ah/451 Wh 3D-battery provides 78% of theoretical capacity and 73% of theoretical energy after 10 formatting cycles. Additionally, the battery prototype exhibits stable performance over more than 200 cycles at C/10 rate. A series of analogous 3D Li accumulators, currently assembled and tested in a pilot plant, represent the first step toward large-scale production of novel 3D Li accumulator.     

Performance analysis of LoRa in the 2.4 GHz ISM band: coexistence issues with Wi-Fi

Telecommunication Systems - Within realization of the visions of the Internet-of-Things (IoT), Low Power Wide Area Networks (LPWANs) are undoubtedly one of the fields that attract high interest...     

Heat losses in Grätzel solar cells

The absorption and reflection spectra of a Grätzel-type solar cell were evaluated in terms of heat losses. Using these experimental data, the temperature distribution inside the solar cell was calculated. The temperature-controlling process in this cell is the heat transfer from the cell to the environment. Assuming the environment temperature of 25°C, the natural air convection leads to the temperature of 46.9°C inside the TiO₂ layer. Forced air convection causes the decrease, up to 30.1°C at the wind speed of 10 m s⁻¹. Variations in the cell dimensions, except the active layer length, have only a small effect on the temperature field, compared to the variations in the heat transfer coefficients.