[2-Cyclo­propyl-4-(4-fluoro­phenyl)quinolin-3-yl]methanol

The title compound, C19H16FNO, crystallizes with two independent mol­ecules in the asymmetric unit. In the two mol­ecules, the dihedral angles between the benzene and quinoline rings are 72.6 (5) and 76.2 (5)°, between the cyclo­propane and quinoline rings they are 65.2 (5) and 66.0 (5)°, and between the benzene and cyclo­propane rings they are 25.9 (5) and 33.9 (5)°. There are inter­molecular O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds, as well as intra­molecular C—H⋯O hydrogen bonds, which may be effective in stabilizing the crystal structure

CELLCOUNTER: Novel Open-Source Software for Counting Cell Migration and Invasion In Vitro

Transwell Boyden chamber based migration/invasion assay is a simple and extensively used approach for the characterization of cell motility in vitro. Cell motility is quantified by counting the number of cells that pass through the filter membrane. The counting is usually performed manually, which is laborious and error prone. We have therefore developed CELLCOUNTER, an application that is capable of recognizing and counting the total number of cells through an intuitive graphical user interface. The counting can be performed in batch, and the counting results can be visualized and further curated manually. CELLCOUNTER will be helpful in streamlining the experimental process and improving the reliability of the data acquisition

Power and limitations of single-qubit native quantum neural networks

Quantum neural networks (QNNs) have emerged as a leading strategy to establish applications in machine learning, chemistry, and optimization. While the applications of QNN have been widely investigated, its theoretical foundation remains less understood. In this paper, we formulate a theoretical framework for the expressive ability of data re-uploading quantum neural networks that consist of interleaved encoding circuit blocks and trainable circuit blocks. First, we prove that single-qubit quantum neural networks can approximate any univariate function by mapping the model to a partial Fourier series. We in particular establish the exact correlations between the parameters of the trainable gates and the Fourier coefficients, resolving an open problem on the universal approximation property of QNN. Second, we discuss the limitations of single-qubit native QNNs on approximating multivariate functions by analyzing the frequency spectrum and the flexibility of Fourier coefficients. We further demonstrate the expressivity and limitations of single-qubit native QNNs via numerical experiments. We believe these results would improve our understanding of QNNs and provide a helpful guideline for designing powerful QNNs for machine learning tasks.Comment: 22 pages including appendix. To appear at NeurIPS 202

Effect of Two-Step Surface Treatment on the Mechanical Properties of Hollow Integrated Core Sandwich Composites with GF/CF Hybrid Face Sheets

ABSTRACT In this study, the effect of a two-step surface treatment on the mechanical properties of hollow integrated core sandwich composites with glass fiber/carbon fiber (GF/CF) hybrid face sheets were investigated. The presence of functional groups on the surface during the two-step treatment was characterized by Fourier transform infrared spectrometer (FTIR). The results of tensile strength on single filaments indicated that no extra loss of fiber strength was observed after the two-step surface treatment for both the glass and carbon fibers. Scanning electron microscopy (SEM) data confirmed the positive effect of the two-step surface treatment on the hollow integrated core sandwich fabric with GF/CF hybrid face sheets. It was found that the hollow integrated core sandwich composites with GF/CF hybrid face sheets showed significant improvements in tensile strength, bending strength and compression strength after the two-step surface treatment, which indicated the two-step surface treatment was efficient

Characteristics of very fast transient currents in ultra high-voltage power system with hybrid reactive power compensation

Hybrid reactive power compensation (HRPC) consists of a stepped controlled shunt reactor (SCSR) and a series compensation (SC), which will find applications in future ultra high-voltage (UHV) power grids to resolve the problems due to the frequent change of reactive power and bulk power transmission. However, very fast transient currents (VFTCs) are inevitably generated during switching, which would lead to insulation breakdown. In the present work, we first develop the equivalent model for HRPC, following which we deduce the expression of VFTCs in the time domain by using an inverse Laplace transform. The analysis indicates that the amplitude and frequency of VFTCs are both affected by the capacitance of the SCSR and of the SC, as well as the line length, stray capacitance, etc. The oscillating frequency, peak, and amplitude of the main frequency of the VFTCs in the substation can be modified by adjusting the silicon-controlled rectifiers in the SCSR when the disconnecting switch in gas-insulated switchgear is switched on. When the disconnecting switch in the SC is switched on, the VFTC oscillation frequency in SCSR decreases with increasing stray capacitance of SC, but the frequency and peak of the VFTC remains quite large. Increasing the line length between the SC and the SCSR suppresses the VFTC in UHV power systems. These results lay the foundation for developing HRPC methods to suppress VFTCs in UHV substations

The generation and migration of bubbles in oil-pressboard insulation needle-plate system

Bubbles in transformer oil can easily lead to partial discharge, which can deteriorate the transformer oil and even breakdown the transformer insulation. To clarify the migration process and the characteristics of bubbles generated in an oil-immersed power transformer exposed to an extremely uneven electric field, we experimentally monitor these phenomena under an extremely nonuniform AC electric field and numerically simulate the migration distance and the migration speed of bubbles with different initial positions and sizes. The results show that the streamer discharge channel formed by a partial discharge in oil is gasified into a bubble channel. After it collides with the surface of the pressboard, its morphology is transformed into approximately spherical bubbles due to the surface tension of the gas-liquid interface. After bubbles are generated in the oil, they move away from areas with a strong electric field due to the electric-field force and gradually approach the oil surface due to the buoyancy force. The experimental results are consistent with the simulation results, which verify the rationality of the simulation model

Study on the breakdown characteristics of multiple-reignition secondary arcs on EHV/UHV transmission lines

A long-gap AC arc with a length of more than ten meters (secondary arc) are normally generated at the short-circuit arc channel after a single-phase-to-ground fault. In previous studies, arc breakdowns of secondary arcs have mainly been considered as electrical breakdowns, ignoring the role of heat in the arc channel. Besides, the extinction-reignition theory of secondary arc, i.e., dielectric strength recovery theory, still lack the support of experimental data. In this study, based on the equivalent experiments performed in the laboratory, the influences of compensation degree of transmission lines, initial recovery voltage gradient of air gap, test current, wind speed, and wind direction on the breakdown characteristics of secondary arcs are studied and statistically analyzed. The laws of the transient recovery voltage (TRV) and of the rate of rise of recovery voltage (RRRV) also studied by considering the influencing factors mentioned above. The results of this study will provide a more complete experimental basis for the theory of extinction–reignition of secondary arcs and a deeper understanding of the transient characteristics of arc breakdow

The Mulberry SPL Gene Family and the Response of MnSPL7 to Silkworm Herbivory through Activating the Transcription of MnTT2L2 in the Catechin Biosynthesis Pathway

SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, as unique plant transcription factors, play important roles in plant developmental regulation and stress response adaptation. Although mulberry is a commercially valuable tree species, there have been few systematic studies on SPL genes. In this work, we identified 15 full-length SPL genes in the mulberry genome, which were distributed on 4 Morus notabilis chromosomes. Phylogenetic analysis clustered the SPL genes from five plants (Malus × domestica Borkh, Populus trichocarpa, M. notabilis, Arabidopsis thaliana, and Oryza sativa) into five groups. Two zinc fingers (Zn1 and Zn2) were found in the conserved SBP domain in all of the MnSPLs. Comparative analyses of gene structures and conserved motifs revealed the conservation of MnSPLs within a group, whereas there were significant structure differences among groups. Gene quantitative analysis showed that the expression of MnSPLs had tissue specificity, and MnSPLs had much higher expression levels in older mulberry leaves. Furthermore, transcriptome data showed that the expression levels of MnSPL7 and MnSPL14 were significantly increased under silkworm herbivory. Molecular experiments revealed that MnSPL7 responded to herbivory treatment through promoting the transcription of MnTT2L2 and further upregulating the expression levels of catechin synthesis genes (F3′H, DFR, and LAR)

Impact of the inductive FCL on the interrupting characteristics of high-voltage CB's during out-of-phase faults

With respect to power systems installed with inductive fault current limiters (FCLs), the impact of an FCL on the out-of-phase fault current level was first analyzed, and thereby a method for determining the critical length of the power transmission tie lines was also given. Based on theoretical analysis and deduction, strict mathematical formulas were obtained to properly describe the relationship between the current limit factor and the recovery voltage of a circuit breaker (CB) as well as the rate of rise of recovery voltage (RRRV). Further, the concrete impacts of an FCL on the maximum and the RRRV of the recovery voltage were analyzed. Regarding out-of-phase faults, a conception of interruption severity as well as its quantitative expression for CBs was introduced, and a formula was established to incorporate the influence from the current limit factor and stray capacitance on the interruption severity of CBs, subsequently followed by detailed investigations. The aforementioned proposed research presents analytical methodology and practical reference for the parameter optimization of the inductive FCL and reliable selection of the interrupting characteristics of the high-voltage CBs