Fabrication of transparent conducting amorphous Zn–Sn–In–O thin films by direct current magnetron sputtering

Amorphous ZnO–SnO2–In2O3 films were grown by direct current magnetron sputtering from vacuum hot pressed ceramic oxide targets of Zn:In:Sn cation ratios 1:2:1 and 1:2:1.5 onto glass substrates. X-ray diffraction analysis showed that the microstructure remained amorphous during annealing at 200 °C for up to 5 hours. By monitoring the electrical resistivity, oxygen content and substrate temperature were optimized during deposition. The optimal films were characterized by Hall Effect, work function and optical spectroscopy measurements. Films of 1:2:1 composition showed the lowest resistivity (7.6×10−4 Ω-cm), when deposited onto substrates preheated to 300 °C. Transmissivity of all films exceeded 80% in the visible spectral region. The energy gap was 3.52–3.74 eV, and the work function ranged 5.08–5.22 eV, suitable for cathode applications in organic light emitting diodes. Overall, the film characteristics were comparable or superior to those of amorphous tin-doped indium oxide and zinc-doped indium oxide films and may serve as viable, lower-cost alternatives

No-boundary measure and preference for large e-foldings in multi-field inflation

The no-boundary wave function of quantum gravity usually assigns only very small probability to long periods of inflation. This was a reason to doubt about the no-boundary wave function to explain the observational universe. We study the no-boundary proposal in the context of multi-field inflation to see whether the number of fields changes the situation. For a simple model, we find that indeed the no-boundary wave function can give higher probability for sufficient inflation, but the number of fields involved has to be very high.Comment: 16 pages, 2 figure

Hydraulic Conductivity of Model Soil-Bentonite Backfills Subjected to Wet-Dry Cycling

The potential for changes in hydraulic conductivity, k, of two model soil-bentonite (SB) backfills subjected to wet-dry cycling was investigated. The backfills were prepared with the same base soil (clean, fine sand) but different bentonite contents (2.7 and 5.6 dry wt %). Saturation (S), volume change, and k of consolidated backfill specimens (effective stress = 24 kPa) were evaluated over three to seven cycles in which the matric suction, Ym, in the drying stage ranged from 50 to 700 kPa. Both backfills exhibited susceptibility to degradation in k caused by wet-dry cycling. Mean values of k for specimens dried at Ym = 50 kPa (S = 30-60 % after drying) remained low after two cycles, but increased by 5- to 300-fold after three or more cycles. Specimens dried at Ym ≥ 150 kPa (S \u3c 30 % after drying) were less resilient and exhibited 500- to 10 000-fold increases in k after three or more cycles. The greater increases in k for these specimens correlated with greater vertical shrinkage upon drying. The findings suggest that increases in hydraulic conductivity due to wet-dry cycling may be a concern for SB vertical barriers located within the zone of a fluctuating groundwater table

Spatial mapping of short-term solar radiation prediction incorporating geostationary satellite images coupled with deep convolutional LSTM networks for South Korea

A practical approach to continuously monitor and provide real-time solar energy prediction can help support reliable renewable energy supply and relevant energy security systems. In this study on the Korean Peninsula, contemporaneous solar radiation images obtained from the Communication, Ocean and Meteorological Satellite (COMS) Meteorological Imager (MI) system, were used to design a convolutional neural network and a long short-term memory network predictive model, ConvLSTM. This model was applied to predict one-hour ahead solar radiation and spatially map solar energy potential. The newly designed ConvLSTM model enabled reliable prediction of solar radiation, incorporating spatial changes in atmospheric conditions and capturing the temporal sequence-to-sequence variations that are likely to influence solar driven power supply and its overall stability. Results showed that the proposed ConvLSTM model successfully captured cloud-induced variations in ground level solar radiation when compared with reference images from a physical model. A comparison with ground pyranometer measurements indicated that the short-term prediction of global solar radiation by the proposed ConvLSTM had the highest accuracy [root mean square error (RMSE) = 83.458 Wcenterdotm−2, mean bias error (MBE) = 4.466 Wcenterdotm−2, coefficient of determination (R2) = 0.874] when compared with results of conventional artificial neural network (ANN) [RMSE = 94.085 Wcenterdotm−2, MBE = −6.039 Wcenterdotm−2, R2 = 0.821] and random forest (RF) [RMSE = 95.262 Wcenterdotm−2, MBE = −11.576 Wcenterdotm−2, R2 = 0.839] models. In addition, ConvLSTM better captured the temporal variations in predicted solar radiation, mainly due to cloud attenuation effects when compared with two selected ground stations. The study showed that contemporaneous satellite images over short-term or near real-time intervals can successfully support solar energy exploration in areas without continuous environmental monitoring systems, where satellite footprints are available to model and monitor solar energy management systems supporting real-life power grid systems

The no-boundary measure in scalar-tensor gravity

In this article, we study the no-boundary wave function in scalar-tensor gravity with various potentials for the non-minimally coupled scalar field. Our goal is to calculate probabilities for the scalar field - and hence the effective gravitational coupling and cosmological constant - to take specific values. Most calculations are done in the minisuperspace approximation, and we use a saddle point approximation for the Euclidean action, which is then evaluated numerically. We find that for potentials that have several minima, none of them is substantially preferred by the quantum mechanical probabilities. We argue that the same is true for the stable and the runaway solution in the case of a dilaton-type potential. Technically, this is due to the inclusion of quantum mechanical effects (fuzzy instantons). These results are in contrast to the often held view that vanishing gravitation or cosmological constants would be exponentially preferred in quantum cosmology, and they may be relevant to the cosmological constant problem and the dilaton stabilization problem.Comment: 31 pages, 9 figure

Automatic segmentation of cardiac structures for breast cancer radiotherapy

Background and purpose We developed an automatic method to segment cardiac substructures given a radiotherapy planning CT images to support epidemiological studies or clinical trials looking at cardiac disease endpoints after radiotherapy. Material and methods We used a most-similar atlas selection algorithm and 3D deformation combined with 30 detailed cardiac atlases. We cross-validated our method within the atlas library by evaluating geometric comparison metrics and by comparing cardiac doses for simulated breast radiotherapy between manual and automatic contours. We analyzed the impact of the number of cardiac atlas in the library and the use of manual guide points on the performance of our method. Results The Dice Similarity Coefficients from the cross-validation reached up to 97% (whole heart) and 80% (chambers). The Average Surface Distance for the coronary arteries was less than 10.3 mm on average, with the best agreement (7.3 mm) in the left anterior descending artery (LAD). The dose comparison for simulated breast radiotherapy showed differences less than 0.06 Gy for the whole heart and atria, and 0.3 Gy for the ventricles. For the coronary arteries, the dose differences were 2.3 Gy (LAD) and 0.3 Gy (other arteries). The sensitivity analysis showed no notable improvement beyond ten atlases and the manual guide points does not significantly improve performance. Conclusion We developed an automated method to contour cardiac substructures for radiotherapy CTs. When combined with accurate dose calculation techniques, our method should be useful for cardiac dose reconstruction of a large number of patients in epidemiological studies or clinical trials

Constructing a counterexample to the black hole complementarity

We propose a regular black hole whose inside generates a de Sitter space and then is finally frustrated into a singularity. It is a modified model which was suggested originally by Frolov, Markov, and Mukhanov. In our model, we could adjust a regular black hole so that its period before going into the extreme state is much longer than the information retention time. During this period an observer could exist who observes the information of the Hawking radiation, falls freely into the regular center of the black hole, and finally meets the free-falling information again. The existence of such an observer implies that the complementary view may not be consistent with a regular black hole, and therefore, is not appropriate as a generic principle of black hole physics.Comment: 8 pages, 5 figure

Mapping rice area and yield in northeastern asia by incorporating a crop model with dense vegetation index profiles from a geostationary satellite

Acquiring accurate and timely information on the spatial distribution of paddy rice fields and the corresponding yield is an important first step in meeting the regional and global food security needs. In this study, using dense vegetation index profiles and meteorological parameters from the Communication, Ocean, and Meteorological Satellite (COMS) geostationary satellite, we estimated paddy areas and applied a novel approach based on a remote sensing-integrated crop model (RSCM) to simulate spatiotemporal variations in rice yield in Northeastern Asia. Estimated seasonal vegetation profiles of plant canopy from the Geostationary Ocean Color Imager (GOCI) were constructed to classify paddy fields as well as their productivity based on a bidirectional reflectance distribution function model (BRDF) and adjusted normalized difference vegetation indices (VIs). In the case of classification, the overall accuracy for detected paddy fields was 78.8% and the spatial distribution of the paddy area was well represented for each selected county based on synthetic applications of dense-time GOCI vegetation index and MODIS water index. For most of the Northeast Asian administrative districts investigated between 2011 and 2017, simulated rice mean yields for each study site agreed with the measured rice yields, with a root-mean-square error of 0.674 t ha−1, a coefficient of determination of 0.823, a Nash-Sutcliffe efficiency of 0.524, and without significant differences (p-value = 0.235) according to a sample t-test (α = 0.05) for the entire study period. A well-calibrated RSCM, driven by GOCI images, can facilitate the development of novel approaches for the monitoring and management of crop productivity over classified paddy areas, thereby enhancing agricultural decision support systems