Microcrystalline-Silicon-Oxide-Based N-Type Reflector Structure in Micromorph Tandem Solar Cells

N-type microcrystalline silicon oxide thin films (n-c-SiO:H) have been deposited by VHF-PECVD (40 MHz) with reactant gas mixtures of CO2/SiH4 and H2. N-c-SiO thin films exhibiting low refractive index value (n600nm∼2), and medium/high conductivity (≧10−9 S/cm) are suitable to be used as an “n-type reflector” in micromorph tandem solar cells. Transmission electron microscopy (TEM) results show that microstructures of n-c-SiO:H thin films contain nanocrystalline Si particles, which are randomly embedded in the a-SiO matrix. This specific microstructure provides n-c-SiO:H thin films excellent optoelectronic properties; therefore, n-c-SiO:H thin films are appropriate candidates for “n-type reflector” structures in Si tandem solar cells

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Typhoon locating and reconstruction from the infra-red satellite cloud image

Abstract—Typhoon inflicts terrible damage due to thunderstorms, violent winds, torrential rain, flooding and extreme high tides. Improving the early typhoon forecast capability is important for the disaster prevention. In recent years, many scholars have made efforts in typhoon center location, typhoon intensity estimation and moving path prediction from the satellite images. Moreover, it may be useful to transfer the useful information of typhoon to the audience in a low bandwidth environment. In this paper, we proposed a novel approach that partitions the satellite cloud image into slices to extract typhoon features. Then we used morphology operations and statistical image classification methods to locate the center and the contour of the typhoon. In addition, we applied the vector quantization method to encode typhoon satellite images owing to its fast image reconstruction capability in different resolutions and regions of interest. The infrared satellite images of 71 typhoons from mature period to decaying period occurred between 1995 and 2006 are tested in this paper. We used the proposed method to recognize, locate and reconstruct typhoon images from these collected satellite cloud images. Experimental results show that the main body of a typhoon image can be segmented effectively from the infrared satellite cloud image with complex background and reconstructed in regions of interest and resolution required. Index Terms—Typhoon center location, typhoon image reconstruction, typhoon recognition I