(E)-4-tert-Butyl-2-(2,6-diisopropyl­phenyl­imino­meth­yl)-6-(morpholinometh­yl)phenol

In the mol­ecule of the title compound, C28H40N2O2, the tert-butyl group is disordered over two positions; site-occupation factors were kept fixed at 0.5. The morpholine ring has a chair conformation. Intra­molecular O—H⋯N hydrogen bonding results in the formation of a planar six-membered ring, which is oriented at a dihedral angle of 0.70 (3)° with respect to the adjacent aromatic ring. The dihedral angle between the benzene rings is 67.66 (3)°

Formation of the third bodies of steel sliding against brass under lubricated conditions

This work investigates the formation mechanism of the third bodies for brass under lubricated conditions. Atribometer based on on-line and radio-nuclide technique (RNT) techniques is used to perform the sliding ex-periment of brass versus steel. The microstructure, micro-hardness and chemical composition of the third bodiesare analyzed by mean of the scanning electron microscope (SEM), focused ion beam microscope (FIB), trans-mission electron microscope (TEM), hardness testers and X-ray photoelectron spectroscopy (XPS). The resultsindicate that the contact pairs show good tribological behaviors and the layered third bodies (mechanicallymixed layer (MML), grain refinement zone (GRZ) and plastic deformation zone (PDZ)) are formed on the brasssurface during sliding. The formation mechanism of the third bodies is explored. The MML gradually forms onthe worn surface in the later stage of the test by proceeding of oxidation reactions. Due to the severe plasticdeformation caused by sliding, the interactional dislocation movements and dynamic recrystallization (DRX) lead to the formation of GRZ with nano-scale grains. The PDZ grains lead to the shear deformation by means offriction stress. Moreover, the generation and accumulation of dislocations result in voids in the PDZ

Evidence of Dark Contents in the Center of NGC 6517

Millisecond pulsars can serve as effective probes to investigate the presence of Intermediate-mass Black Holes (IMBHs) within Galactic globular clusters (GCs). Based on the standard structure models for GCs, we conduct simulations to analyze the distributions of pulsar accelerations within the central region of NGC 6517. By comparing the measured accelerations of pulsars obtained from their period derivatives $\dot P$ to the simulated distribution profiles, we demonstrate that a central excess of dark mass is required to account for the measured accelerations. Our analysis, which relies on existing pulsar timing observations, is currently unable to differentiate between two possible scenarios: an IMBH precisely situated at the core of the cluster with mass $\gtrsim 9000^{+4000}_{-3000}~M_{\odot}$, or a central concentration of stellar mass dark remnants with a comparable total mass. However, with additional acceleration measurements from a few more pulsars in the cluster, it will be possible to differentiate the source of the nonluminous matter.Comment: 6 pages, 3 figures, 1 table. Accepted for publication in MNRA

A novel actuator-internal micro/nano positioning stage with an arch-shape bridge type amplifier

This paper presents a novel actuator-internal two degree-of-freedom (2-DOF) micro/nano positioning stage actuated by piezoelectric (PZT) actuators, which can be used as a fine actuation part in dual-stage system. To compensate the positioning error of coarse stage and achieve a large motion stroke, a symmetrical structure with an arch-shape bridge type amplifier based on single notch circular flexure hinges is proposed and utilized in the positioning stage. Due to the compound bridge arm configuration and compact flexure hinge structure, the amplification mechanism can realize high lateral stiffness and compact structure simultaneously, which is of great importance to protect PZT actuators. The amplification mechanism is integrated into the decoupling mechanism to improve compactness, and to produce decoupled motion in X- and Y- axes. An analytical model is established to explore the static and dynamic characteristics, and the geometric parameters are optimized. The performance of the positioning stage is evaluated through finite element analysis (FEA) and experimental test. The results indicate that the stage can implement 2-DOF decoupled motion with a travel range of 55.4×53.2 μm2, and the motion resolution is 8 nm. The stage can be used in probe tip-based micro/nano scratching

Interpretable Motion Planner for Urban Driving via Hierarchical Imitation Learning

Learning-based approaches have achieved remarkable performance in the domain of autonomous driving. Leveraging the impressive ability of neural networks and large amounts of human driving data, complex patterns and rules of driving behavior can be encoded as a model to benefit the autonomous driving system. Besides, an increasing number of data-driven works have been studied in the decision-making and motion planning module. However, the reliability and the stability of the neural network is still full of uncertainty. In this paper, we introduce a hierarchical planning architecture including a high-level grid-based behavior planner and a low-level trajectory planner, which is highly interpretable and controllable. As the high-level planner is responsible for finding a consistent route, the low-level planner generates a feasible trajectory. We evaluate our method both in closed-loop simulation and real world driving, and demonstrate the neural network planner has outstanding performance in complex urban autonomous driving scenarios.Comment: 6 pages, 8 figures, accepted by IROS202

Discovery and Timing analysis of new pulsars in globular cluster NGC 5024: new observations from FAST

NGC 5024 (M53) is the most distant globular cluster (GC) with known pulsars. In this study, we report the discovery of a new binary millisecond pulsar PSR J1312+1810E (M53E) and present the new timing solutions for M53B to M53E, based on 22 observations from the Five-hundred-meter Aperture Spherical radio Telescope (FAST).These discoveries and timing work benefit from FAST's high sensitivity. We find that M53C is the only isolated millisecond pulsar known in this distant globular cluster, with a spin period of 12.53 ms and spin period derivative of $5.26 \times 10^{-20} \, \rm s \; s^{-1}$. Our results reveal the orbital periods of 47.7, 5.8, and 2.4 days for M53B, D, and E, respectively. The companions, with a mass of 0.25, 0.27, and 0.18 ${\rm M}_\odot$, respectively, are likely to be white dwarf stars; if they are extended objects, they don't eclipse the pulsars. We find no X-ray counterparts for these millisecond pulsars in archival $Chandra$ images in the band of 0.3-8 keV. The characteristics of this pulsar population are similar to the population of millisecond pulsars in the Galactic disk, as expected from the low stellar density of M53.Comment: 10 pages, 4 figures, accepted for publication in ApJ