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A limitation of simultaneous localization and mapping (SLAM) is the lack of consideration of dynamic objects in the environment, resulting in degradation of map quality and positioning accuracy. This article introduces a 2-D tightly-coupled LiDAR-Inertial Odometry and Mapping framework (DY-LIO) to remove dynamic objects for a better SLAM. The main innovations are based on the process of LiDAR point cloud and occupancy grid map: 1) with respect to LiDAR point cloud processing, based on deskewing and aligning the point cloud through factor-graph-optimized inertial measurement unit (IMU) preintegration, the alignment errors are utilized to identify dynamic objects. Besides, a different property of static and dynamic cloud points is introduced to reduce the misidentification error and 2) in terms of occupancy grid map processing, a novel probabilistic update method is presented to enhance the filterability of dynamic grid and accelerate the filtering process. Based on these novel strategies, DY-LIO can guarantee accurate localization and clean map estimation in dynamic environments. The experimental results on realistic high dynamic datasets demonstrate that DY-LIO greatly outperforms the current mainstream 2D-SLAM algorithm (Cartographer) in terms of the mapping effect and localization accuracy, with high efficiency in dynamic environments.

Dy-free sintered magnets were fabricated by blending Neo powder with different grain boundary diffusion (GBD) alloy powders. Cu, CeAl, and CeAlCu have a negative effect on Hcj of magnets, while PrAlCu and AlCuGa have a positive effect. The PrAlCu-added magnet achieves the best magnetic properties among all magnets with the additions of different diffusion alloys. With increasing PrAlCu from 0–10 wt.%, Hcj of the magnets gradually increases from the original 14.5–19.2 kOe. The magnet with 7.5 wt.% PrAlCu obtains an Hcj of 18 kOe and (BH)max of 39.1 MGOe. It is found that Pr and Cu in PrAlCu alloy are mainly distributed at grain boundary and triple junctions (TJs), leading to a reduced coupling among grains, thus an enhanced Hcj. The grain boundary engineering by adding an appropriate alloy is an effective method to improve Hcj of Dy-free NdFeB magnets.

Within the series of the equiatomic REAlRh compounds, the representatives with RE= Y, La–Nd, Gd, Ho, Tm and Yb have been synthesized. The members with RE= Sm, Tb, Dy, Er and Lu, however, had not yet been reported. They have now been synthesized and structurally as well as magnetically and NMR-spectroscopically characterized. All members crystallize isostructurally in the orthorhombic TiNiSi type, similar to most of the known analogues. The evolution of their unit cell volumes exhibits the expected decrease due to the lanthanide contraction. While LuAlRh shows Pauli-paramagnetic behavior, SmAlRh, TbAlRh, DyAlRh, ErAlRh, and TmAlRh exhibit antiferromagnetic ground states with Néel temperatures between TN= 45 and 4 K. 27Al MAS-NMR investigations have been conducted on YAlRh and LuAlRh. The results of quantum-chemical calculations support the conclusions drawn from the NMR-spectroscopic study and give information on the charge distribution in these intermetallic aluminum metallides.

The magnetocaloric effect (MCE) is currently intensively investigated in various rare earths (RE)-containing magnetic solids, not only for developing appropriate magnetocaloric materials (MCMs) for cryogenic magnetic cooling but also for deepening our understanding into the inherent physical properties of these materials. Here, we provide a systematic experimental investigation into a series of new RE2CuTiO6(RE= Dy, Ho, Er) double-perovskite (DP) oxides regarding the structural and magnetic properties, especially for their cryogenic MCE and magnetic-phase transition (MPT). All of these RE2CuTiO6oxides crystallize in a B-site-ordered hexagonal DP-type structure with the symmetry of the crystallographic space group P6̅m2. These DP oxides exhibit magnetic ordering, with MPT temperatures of approximately 2.7, 2.2, and 2.7 K for Dy2CuTiO6, Ho2CuTiO6, and Er2CuTiO6, respectively. The magnetocaloric performances of the RE2CuTiO6DP oxides were characterized by the peak values of magnetic entropy change, the temperature-averaged magnetic entropy change (5K-lift), and relative cooling powers. These magnetocaloric parameters were deduced to be 18.7/17.9 J/kgK and 298.2 J/kg for Dy2CuTiO6, 12.5/12.2 J/kgK and 273.9 J/kg for Ho2CuTiO6, and 13.8/12.9 J/kgK and 188.4 J/kg for Er2CuTiO6under a magnetic field change of 0–5 T. These values are comparable to those of most reported RE-containing magnetocaloric materials, indicating that these RE2CuTiO6DP oxides are promising candidates for cryogenic magnetic cooling applications.

Polyoxometalates (POMs) with various coordination fashions are versatile ligands for constructing single-ion magnets (SIMs), but enforcing POM-SIMs with a specific geometry remains a synthetic challenge. Herein, we synthesized a POM-cocrystallized DyIII–SIM [Dy(OPPh3)4(H2O)3][PW12O40]·4EtOH (1Dy) and a POM-ligated DyIII–SIM [{Dy(OPPh3)3(H2O)3}{PW12O40}]·Ph3PO·H2O (2Dy) with pentagonal bipyramidal local coordination geometry. Magnetic measurements indicate that 1Dydisplays field-induced single-molecule magnet (SMM) behavior and the relaxation is dominated by under-barrier processes. 2Dyexhibits spin–lattice relaxation at a broader temperature region with a reversal barrier over 300 K. Magneto-structural analysis reveals that the enhancement of SMM behavior originated from the equatorial replacement of Ph3PO by POM, which strengthens the axial anisotropy in 2Dy. Luminescent experiments indicate that the characteristic DyIIIemissions of 1Dyare covered up by the strong π–π* emission of Ph3PO at low-temperature regions. As for 2Dy, partial DyIIIemission persists thanks to the antenna effect between DyIIIand POM.

In order to further study the hydrogen storage mechanism of Mg-based hydrogen storage materials, Mg90Ce5Y5alloy was used as the basis, and three kinds of heavy rare earth oxides were doped into the alloy by ball milling technology. The microstructure and hydrogen storage properties were characterized by XRD, SEM, TEM and PCI. The results show that the hydrogen absorption rate and discharge rate of modified Mg90Ce5Y5alloy are significantly increased, and the performance is Er2O3> Dy2O3> Yb2O3. The hydrogen storage capacity of Er2O3catalyzed samples is 5.02 wt%, which is higher than 4.82 wt% and 4.80 wt% of Dy2O3and Yb2O3catalyzed samples. The hydrogen absorption saturation rate of the sample catalyzed by Er2O3for 2 min is ∼90 %, the complete release of hydrogen only takes 50 min at 573 K, and the dehydrogenation activation energy is 76.9 kJ/mol. The hydrogen absorption and emission rate is fast, and the dehydrogenation activation energy is slightly lower than that of the other two catalysts. In the process of hydrogen absorption and desorption, the three catalysts exhibit different phase transitions, namely DyH2↔DyH3, ErH2↔ErH3and irreversible YbH2. DyH2↔DyH3, ErH2↔ErH3phase transitions have the "hydrogen pump" effect, which can effectively improve the hydrogen absorption and desorption kinetic rate of Mg90Ce5Y5alloy. Some nano-rare earth compounds and phase transformation significantly improve the kinetic properties of the alloy. However, the enthalpy change of all three catalytic alloys is around 76 kJ/mol H2, which is considered only a slight improvement in thermodynamic properties.

In the pursuit of high-performance single-molecule magnets (SMMs), incorporating intramolecular magnetic coupling emerges as a pivotal strategy. Among these, d-f SMMs have garnered significant attention due to their remarkable versatility, which lies in their ability to tune coordination environments and facilely substitute metal centers. However, achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable challenge. While mononuclear hexagonal bipyramidal (D6h) DyIIISMMs have been successfully isolated, the exploration of d-f SMMs featuring D6h-lanthanide metal centers remains uncharted territory. In this study, we employed planar bipodal ligands in conjunction with “staple-like” axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f SMM. Remarkably, this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K, thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ions. Notably, the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field — a characteristic distinct from mononuclear SMMs. These findings shed light on a deliberate design approach for d-f SMMs, emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic interactions. This synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.

Single-molecule magnets (SMMs) are a kind of nanosized magnetic materials that are capable of storing massive bytes of information. Strongly coupling the spin centers in a proper manner is a usual approach to promote the working temperature (or blocking temperature) for SMMs. Electron delocalized radicals have been widely employed to accomplish this job. Here, we show a new manner by using weak but multiple B–Hδ−⋯ Dy3+inverse hydrogen bonding (IHB) interactions to control the magnetic couplings in a series of dimeric dysprosiacaborane SMMs. This approach leads to a record high TB100sof 10 K among non-radical bridged dimeric SMMs, which is mainly ascribed to strong ferromagnetic coupling (4.38 cm−1) and the proper alignment of the magnetic principle axes of the adjacent dysprosium(III) ions. In verifying by theoretical calculations, these results demonstrate that IHB interactions can be used to construct strong axial ferromagnetic coupling and enhancing magnetic blocking temperature for SMMs.

The crystal structures of the U3Si2-related intermetallic compounds RE2Pd2Cd (RE= Nd, Sm, Gd, Dy) and RE2Ga2Mg (RE= Tb, Er, Tm, Lu) were studied from single crystal X-ray diffraction data at T= 90 K in order to understand the slightly enhanced U33displacements of the 2apositions in their room temperature structures. The compounds Sm2Pd2Cd, Gd2Pd2Cd and Dy2Pd2Cd show a decrease of the ratio of U33to U11for the cadmium atoms, leading to a more isotropic behavior at low temperature, keeping the P4/mbmspace group symmetry. Nd2Pd2Cd shows a translationengleichesymmetry reduction to space group P4bmalong with a weak puckering effect with shorter (342.7 pm) and longer (345.7 pm) Cd–Nd distances within the Cd@Nd8square prisms. This new, non-centrosymmetric superstructure variant was also observed for the magnesium compounds Tb2Ga2.069Mg0.931, Er2Ga2.104Mg0.896, Tm2Ga2.097Mg0.903and Lu2Ga2.173Mg0.827, which show small degrees of Mg/Ga mixing.

A dual-main-phase magnet with excellent thermal stability was prepared by co-mixing two types of magnetic powders, which was the conventional N55-grade powder without Dy elements, while the Co and Dy contents reached 50 wt% and 6 wt% respectively in another Co-rich powder. Studies showed that the magnetic properties along with the thermal stabilities of the magnets exhibited significant differences with the changes in the mixing ratio of the two powders. Especially, when mixing the two powders in equal proportions, a great remanence temperature coefficient of −0.0725 %/°C at 20–100 °C was obtained with a rather high Curie temperature of 581 °C, possessing its magnetic properties with Br = 12.58 kGs, Hcj = 15.9 kOe, and (BH)max = 36.88 MGOe. Note that as the proportion of Co-rich powder increased to 2/3, although the Curie temperature of the prepared magnets further increased to 622 °C, both the remanence temperature coefficient and the magnetic properties deteriorated significantly. The phase composition and microstructure analyses revealed that when the proportion of added Co-rich component exceeded 1/2, the RE(Fe,Co)2B phase transformed into the RE(Fe,Co)4B phase, and a significant amount of RE(Fe,Co)1.8B0.2phase precipitated at the grain boundaries, leading to a deterioration in magnetic performance. In addition, dynamic domain evolution analyses under variable temperature conditions demonstrated the positive effect of the appropriate introduction of Co/Dy on the anti-demagnetization in high temperatures. This work provides insights and an experimental foundation for the development of high-performance magnets with high thermal stability, used in high-temperature environments.

Two heteroatom-templated Dy(III)-confined polyoxotungstates [H2N(CH3)2]7Na7[Dy2(H2O)7(W4O9)(HPSeW15O54)(a-SeW9O33)2]·31H2O (1) and [H2N(CH3)2]14K2Na18{[Dy2(H2O)13W14O40]2[a-SeW9O33]4[HPSeW15O54]2}·44H2O (2) were synthesized by a one-pot aqueous reaction and structurally characterized. The most distinctive structural feature of complexes 1& 2is the simultaneous presence of both trivacant Keggin [a-SeW9O33]8–and Dawson [HPSeW15O54]10–building blocks containing P(III)–Se(IV) heteroatoms. The trimeric polyanion of 1can be represented as a fusion of two trivacant Keggin [a-SeW9O33]8–and Dawson [HPSeW15O54]10–building units encapsulating the [Dy2(H2O)7(W4O9)]12+cluster. On the other hand, hexameric polyoxoanions of 2are described as four trivacant Keggin [a-SeW9O33]8–and two Dawson [HPSeW15O54]10–, building units anchoring a [Dy4(H2O)26W28O80]20+cluster. The magnetic investigation revealed the presence of significant magnetic anisotropy and slow relaxation of magnetization behavior for complex 1with a phenomenological energy barrier, Ueff= 13.58 K in the absence of an external magnetic field, and Ueff= 24.57 K in the presence of a 500 Oe external dc magnetic field. On the other hand, complex 2favors the QTM relaxation process in the absence of an external magnetic field and shows field-induced slow relaxation of magnetization with Ueff= 11.11 K at 1500 Oe applied dc field. The in-depth analysis of magnetic relaxation dynamics shows that the relaxation process follows the Orbach as well as Raman relaxation pathways. Further, the ab initiocalculation of the studied complexes confirms that the highly axial ground and first excited energy states (containing pure highest mJstates) are responsible for the observed single-molecule magnet (SMM) behavior. Remarkably, this is the first example of a mixed heteroatom-based Dy(III)-substituted polyoxotungstate with both trimeric Keggin [a-SeW9O33]8–and Dawson [HPSeW15O54]10–building units showing SMM behavior.

• Introduction of cu into the grain boundary phase through diffusion treatment, transforming the brittle RE-rich grain boundary phase into a ductile (Tb,Dy)Cu grain boundary phase. • The semi-coherent interface between the (Tb,Dy)Fe 2 matrix phase and (Tb,Dy)Cu grain boundary phase was achieved. • The tensile strength, bending strength, and fracture toughness at room temperature increased to 44.6 MPa, 106.8 MPa, and 2.36 MPa m1/2, respectively, which were 2, 2.4, and 1.5 times those of the original sample. • Magnetostriction reached 1448 ppm, suggesting minimal influence of grain boundary diffusion on the matrix phase. Giant magnetostrictive Tb-Dy-Fe alloys in the form of thin sheets or fine wires are required in precision micro-actuators and sensors. However, Tb-Dy-Fe alloys are too brittle to undergo machining and application. In the present work, we investigated the effects of diffusing the Dy 36 Cu 64 alloy into the grain boundary phases of the <110>-oriented Tb 0.30 Dy 0.70 Fe 1.95 alloy to modify the microstructural, mechanical, and magnetostrictive properties. Microstructural analysis revealed the introduction of Cu into the grain boundary phase through the diffusion treatment, transforming the brittle rare earth (RE)-rich grain boundary phase into a ductile (Tb,Dy)Cu grain boundary phase and changing the non-coherent interface to a semi-coherent one between the (Tb,Dy)Fe 2 matrix phase and the grain boundary phase without affecting the microstructure of the matrix phase. The as-diffused Tb 0.30 Dy 0.70 Fe 1.95 alloy exhibited significantly improved mechanical properties, with its tensile strength, bending strength, and fracture toughness at room temperature increasing to 44.6 MPa, 106.8 MPa, and 2.36 MPa m1/2, respectively, which were 2, 2.4, and 1.5 times those of the non-diffused sample. This was attributed to the formation of ductile (Tb,Dy)Cu grain boundary phase and semi-coherent interfaces. Furthermore, the magnetostrictive strain of the as-diffused Tb 0.30 Dy 0.70 Fe 1.95 alloy reached 1448 ppm, suggesting that there was minimal impact on the magnetostrictive properties, due to the small influence of grain boundary diffusion on the matrix phase. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanoneedle-shaped superhydrophilic Dy@Ni-MOF on carbon cloth is fabricated via Dy-induced valence electronic perturbation approach. Studies demonstrate that the strong electronic interaction of Dy/Ni species promotes the adsorption of oxygen-containing intermediates and accelerates reaction kinetics, thereby boosting OER performance.

A series of chiral heterometallic Ln–Co clusters, denoted as Co2Lnand Co3Ln2(Ln = Dy and Er), were synthesized by reacting the chiral chelating ligand (R/S)-2-(1-hydroxyethyl)pyridine (Hmpm), CoAc2·4H2O, and Ln(NO3)3·6H2O. Co2Lnand Co3Ln2exhibit perfect mirror images in circular dichroism within the 320–700 nm range. Notably, the Co2Erand Co3Er2clusters display pronounced magnetic circular dichroism (MCD) responses of the hypersensitive f–f transitions 4I15/2–4G11/2at 375 nm and 4I15/2–2H11/2at 520 nm of ErIIIions. This study highlights the strong magneto-optical activity associated with hypersensitive f–f transitions in chiral 3d–4f magnetic clusters.

In this study, bulk Mg-Dy-Zr alloys with an average grain size of 78.8 nm and a diameter of 12.1 mm were prepared by room temperature rotary swaging (RTRS). The evolution of the microstructure and texture during the grain refinement process was investigated using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that the original texture consisting of arbitrarily oriented recrystallized grains and ED∥[10 1‾0] deformed grains is transformed into an ED∥[10 1‾0] texture after the alloy processed by RTRS. The formation of nanograins is induced by a large number of tensile twins, deformation bands, and dislocation arrays synergistically adapting to the strain. The yield strength and ultimate tensile strength of the nanograin alloys obtained are substantially increased to 281% and 190% of those of the as-extruded alloys. The strength improvement of the alloys is a result of the combined effect of grain refinement and dislocation strengthening, in which nanograin strengthening dominates.

In this study, two octa-nuclear lanthanide complexes consisting of a templated Ln8(Ln = Tb, Dy) cluster and a ″4 + 4″ type Schiff-base covalent organic macrocycle, named Ln8L4+4, were constructed successfully. The stepwise solution assembly process of Tb8L4+4from the initial organic subcomponents and metal templates was tracked as Tb1L1+2→ Tb2L1+2→ Tb3L1+2→ Tb3L2+2→ Tb4L2+2→ Tb4L3+2→ Tb5L3+2→ Tb6L3+2→ Tb8L4+4, through ESI-MS technology. Interestingly, Tb8L4+4can be used as a sensitive and selective fluorescence-sensing material to determine the level of dipicolinic acid (DPA), and Dy8L4+4has the characteristics of a single molecule magnet behavior.

As one of the potential candidates of nonlinear-optical (NLO) materials, rare-earth chalcophosphates have demonstrated promising properties. Here, KREP2S6(RE = Sm, Gd, Tb, Dy) were synthesized using the facile RE2O3-B-S solid-state method. They crystallize with a monoclinic chiral P21structure, and their layer structures are built by isolated ethane-like P2S6dimers and RES8bicapped trigonal prisms built {[RE2S15]24–}∞layers. By comparing the structures with related ones, the change of the alkali metal or RE3+ions can cause structural transformation. Their band gaps are tunable between 2.58 and 3.79 eV, and their powder samples exhibit good NLO properties. Theoretical calculations suggest that the NLO properties are mainly contributed by P2S6units and {[RE2S15]24–}∞layers synergistically, in which {[RE2S15]24–}∞layers and P2S6units dominate the contribution to the band gap and second-harmonic-generation response, respectively. This work enriches the application of rare-earth chalcophosphates as NLO materials.