Theory of MBE Growth of Nanowires on Reflecting Substrates

Selective area growth (SAG) of III-V nanowires (NWs) by molecular beam epitaxy (MBE) and related epitaxy techniques offer several advantages over growth on unpatterned substrates. Here, an analytic model for the total flux of group III atoms impinging NWs is presented, which accounts for specular re-emission from the mask surface and the shadowing effect in the absence of surface diffusion from the substrate. An expression is given for the shadowing length of NWs corresponding to the full shadowing of the mask. Axial and radial NW growths are considered in different stages, including the stage of purely axial growth, intermediate stage with radial growth, and asymptotic stage, where the NWs receive the maximum flux determined by the array pitch. The model provides good fits with the data obtained for different vapor–liquid–solid and catalyst-free III-V NWs.

Is Cork Growth a Reliable Proxy for Stem Diameter Growth in Cork Oak (Quercus suber L.)? Implications for Forest Management under Climate Change in Mediterranean Regions

Cork-ring widths have been extensively used in dendroecological studies assessing the relationship between cork growth patterns and climate (precipitation and temperature). Generally, cork growth is assumed as a proxy for stem diameter growth to address cork oak (Quercus suber L.) growth sensitivity to climate and cork yield modeling. Cork growth represents a large part of stem radial increment in this species due to the enhanced activity of phellogen when compared to the cambium activity; thus, similar inter-annual variations of cork-ring widths and tree diameter growth might be expected. However, so far, the influence of rainfall and temperature on stem diameter growth has scarcely been addressed; moreover, it is still not clear whether tree size relates, and in what way, to the variations in radial growth of cork and stem diameter and whether these reflect (proportional) quantitative variations in stem basal area growth. In this study, we computed the annual growth of cork and of stem diameter at breast-height in data series of 47 trees, from 2000 to 2012, corresponding to a full cork production cycle. Results showed a tight link between cork-ring width and stem diameter growth indices. However, while cork growth strongly correlated with climate conditions in autumn–winter prior to the growing season, stem diameter growth correlated with climate conditions of the current growing season, and, more importantly, it was tree size-related. The extrapolation from cork-ring increments to stem basal area growth is likely to progressively underestimate tree growth and biomass increment in larger cork oaks and to further bias it due to climate change effects in the Mediterranean region.

Vaccine policy in Austria and Germany should work

Significance It comes after Austria became the first European country to announce it would make vaccinations mandatory for the adult population. Both countries have among the lowest vaccination rates in Western Europe, which has resulted in soaring infection rates, hospitalisations, and the re-introduction of lockdown restrictions. Impacts Germany and Austria are likely to experience protests over the coming weeks in opposition to vaccination policy. More European countries could consider implementing mandatory vaccines amid concerns over the new Omicron COVID-19 variant. Persistently high COVID-19 infections would slow down the German government’s social and economic reform agenda. Slower euro-area growth as a result of new lockdown measures could see the ECB extend its loose monetary policies.

Fabrication and optical characterization of GaN quasi-phase matching crystal by double polarity selective area growth in metal organic vapor phase epitaxy

The fabrication of ultra-violet (UV) second-harmonic generation (SHG) (UV-SHG) devices requires GaN quasi-phase matching (GaN-QPM) crystals with periodically arranged polar GaN. For fabricating GaN-QPM crystals, the double polarity selective area growth (DP-SAG) using carbon mask technique is employed. However, the growth of narrow (2–4 [Formula: see text]m) pitch pattern GaN-QPM crystals, which is necessary for UV-SHG devices, has not been reported using this technique. Herein, we report the successful fabrication of 4 [Formula: see text]m pitch pattern GaN-QPM. We fabricated a thick GaN-QPM crystal at the optimized V/III ratio. Through optical characterization, we observed SHG generation from the GaN-QPM crystal fabricated using DP-SAG.

Modelling Industrial Growth in The Coastal Area of Semarang Metropolitan Region Using GeOBIA

Central Java Province has the manufacturing industry sector as the largest economic contributor. This manufacturing industry sector growth is mainly supported by the strategic location and infrastructures on the northern coast of Central Java Province (Kendal-Semarang-Demak). However, the high increase of industrial built-up area in the coastal area of Semarang Metropolitan Region has an impact on the conversion of coastal land if the growth cannot be controlled through the spatial plan implementation. This study identified the direction and trends of industrial growth in the coastal area of Semarang Metropolitan Region in 2015-2020 and the industrial growth prediction in 2030 for assessing the industrial zones in spatial plan 2011-2031. This research consists the estimation of industrial built-up area growth using the combination of GeOBIA method and manual interpretation of high-resolution satellite imagery (Sentinel-2A) from 2015 to 2020 and assessment of industrial zones in spatial plan based on the industrial growth prediction model in 2030 using the Cellular Automata Markov (CA-Markov). Industrial built-up area tends to grow towards the western and eastern part of the coastal area of Semarang Metropolitan Region based on map distribution and area growth. The results showed more than 20 % of industrial land is not suitable with the spatial plan in 2020 and it predicted will be increased in 2030, it is necessary to increase the efforts to control the spatial use.