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Abstract Time dependent observations of point-to-point correlations of the velocity vector field (structure functions) are necessary to model and understand fluid flow around complex objects. Using thermal gradients, we observed fluid flow by recording fluorescence of$${\text{He}}_{2}^{*}$$ excimers produced by neutron capture throughout a ~ cm3volume. Because the photon emitted by an excited excimer is unlikely to be recorded by the camera, the techniques of particle tracking (PTV) and particle imaging (PIV) velocimetry cannot be applied to extract information from the fluorescence of individual excimers. Therefore, we applied an unsupervised machine learning algorithm to identify light from ensembles of excimers (clusters) and then tracked the centroids of the clusters using a particle displacement determination algorithm developed for PTV.more » « less
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We report a novel manufacturing approach to fabricate liquid metal-based, multifunctional microcapillary pipettes able to provide electrodes with high electrical conductivity for high frequency electrical stimulation and measurement. Four-dimensional single cell manipulation has been realized by applying multi-frequency, multi-amplitude, and multi-phase electrical signals to the microelectrodes near the pipette tip to create a 3D dielectrophoretic trap and 1D electrorotation simultaneously. Functions such as single cell trapping, transferring, patterning, and rotation have been accomplished. Cell viability and multi-day proliferation characterization has confirmed the biocompatibility of this approach. This is a simple, low cost, and fast fabrication approach that requires no cleanroom and photolithography to manufacture 3D microelectrodes and microchannels accessible to a wide user base for broad applications.more » « less
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Abstract The superτ-charm facility (STCF) is an electron–positron collider proposed by the Chinese particle physics community. It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5 × 1035cm−2·s−1or higher. The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory — the BEPCII, providing a unique platform for exploring the asymmetry of matter-antimatter (charge-parity violation), in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions, as well as searching for exotic hadrons and physics beyond the Standard Model. The STCF project in China is under development with an extensive R&D program. This document presents the physics opportunities at the STCF, describes conceptual designs of the STCF detector system, and discusses future plans for detector R&D and physics case studies.more » « less
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