Recent advancements in deep learning, high-fidelity simulation, and robotic hardware have propelled significant progress in Physical Artificial Intelligence (AI). This field marks a revolutionary step in the evolution of AI by combining the precision of physical laws with the adaptability of machine learning. In this paper, we review the development of Physical AI and its taxonomy by examining the relevant literature, categorizing it into three sub-domains: Physical-Informed AI, Generative Physical AI, and Embodied AI. These sub-domains primarily tackle scientific and engineering challenges, create physics-plausible scenarios, and enable robots or autonomous vehicles to interact with the physical world. This approach also addresses the questions of how to perceive, generate, and interact with the physical world by integrating physics with AI algorithms. Additionally, we discuss related benchmarks and datasets. Finally, we outline the current challenges and propose potential opportunities for future research.

To address the high cognitive demands of augmented assembly and repair for operators, this paper presents a lightweight augmented reality framework combining object tracking and registration. Specifically, we propose a new object tracking architecture named YOLOv7-TinyMRN which is improved from YOLOv7-Tiny, reducing GFLOPS by 11.45

Zero area compressibility (ZAC) is an extremely rare mechanical response that exhibits an invariant two-dimensional size under hydrostatic pressure. All known ZAC materials are constructed from units in two dimensions as a whole. Here, we propose another strategy to obtain the ZAC by microscopically orthogonal-braiding one-dimensional zero compressibility strips. Accordingly, ZAC is identified in a copper-based compound with a planar [CuO 4 ] unit, Cu 2 GeO 4 , that possesses an area compressibility as low as 1.58(26) TPa −1 over a wide pressure range from ≈0 GPa to 21.22 GPa. Based on our structural analysis, the subtle counterbalance between the shrinkage of [CuO 4 ] and the expansion effect from the increase in the [CuO 4 ]-[CuO 4 ] dihedral angle attributes to the ZAC response. High-pressure Raman spectroscopy, in combination with first-principles calculations, shows that the electron transfer from in-plane bonding d x 2 -y 2 to out-of-plane nonbonding d z 2 orbitals within copper atoms causes the counterintuitive extension of the [CuO 4 ]-[CuO 4 ] dihedral angle under pressure. Our study provides an understanding on the pressure-induced structural evolution of copper-based oxides at an electronic level and facilitates a new avenue for the exploration of high-dimensional anomalous mechanical materials.

Materials with negative/zero area compressibility (NAC or ZAC), which expand or keep constant along two directions under hydrostatic pressure, are very rare but of great scientific and engineering merits. Here, we investigate “wine-rack” architecture, which is the most prevailing for the pressure-expansion effect in materials, and identify that two allotropes (Ag3BO3-I and -II ) of Ag3BO3 have the ZAC and NAC effects, respectively, by the first-principles calculations. Structural analysis discloses that the competition between the contraction effect from the bond length/angle shrinkage and the expansion effect from the angle closing between O-Ag-O bars and the (a , b ) plane dominates the occurrence of ZAC/NAC, and the framework openness governs the competing balance in this system. This work deepens the understanding of “wine-rack” models and enriches the NAC/ZAC family.

Negative-thermal-expansion (NTE) materials violate the common knowledge of "thermal expansion and cold contraction" in solids and embrace various physical mechanisms. In most phonon-driven NTE materials, an open-framework structure is necessary to accommodate the spatially anisotropic phonon excitations of the bridged atoms, but such a structural feature may result in structural instability at a high temperature. Herein, we focus on gamma-LiBO2 with a closed-framework diamond-like structure and identify its uniaxial NTE behavior over the largest temperature range (100-850 K) among this structural family. As the temperature increases, the synergetic structural modification of the constituent structural groups, i.e., the stretching and bending of the Li-O bonds in floppy [LiO4] and the tension or rotation in the [BO4] group, accounts for NTE along the c-axis. Our study unveils that, apart from the anisotropic phonon excitations of individual atoms, the preferred phonon excitations of structural groups are also able to generate NTE, which would update the understanding of the NTE mechanism and guide the further exploration of phonon-driven NTE materials.

Laser crystals, serving as the laser gain medium, are key materials in all-solid-state lasers. Due to considerable thermal expansion and low thermal conductivity, the performance of conventional laser crystals strongly depends on thermal management systems to improve the laser quality and power, which inevitably restricts the development of laser technology. In this work, a new potential laser crystal of Mn2+-doped Zn4B6O13 (ZBO) with a low thermal expansion and high thermal conductivity was grown and characterized. The strong luminescence emission at 539 nm in ZBO:Mn2+ was observed, with a long lifetime of 16.20(7) ms, and the corresponding absorption bands in the range of 410-460 nm fall within the spectra of GaN- or InGaN-based laser diodes. In variable-temperature fluorescence spectra, promoted by relaxation on the parity-forbidden 4T1-to-6A1 transition from the increased phonon number, an abnormal negative thermal quenching was manifested below 140 K, with the lifetime consistently greater than 10 ms over the whole temperature range of 80-500 K. Meanwhile, ZBO:Mn2+ manifests very low thermal expansion (3.1 MK-1) and high thermal conductivity (27.44(6) W/(mK)) at room temperature (300 K). These excellent thermal properties, combined with good optical properties, make ZBO:Mn2+ an outstanding gain medium for green laser generation. Our study confirms that ZBO is a promising laser matrix crystal.

Materials with negative/zero area compressibility (NAC or ZAC), which expand or keep constant along two directions under hydrostatic pressure, are very rare but of great scientific and engineering merits. Here, we investigate "wine-rack" architecture, which is the most prevailing for the pressure-expansion effect in materials, and identify that two allotropes (Ag3BO3-I 3 BO 3- I and-II) II ) of Ag3BO3 3 BO 3 have the ZAC and NAC effects, respectively, by the first-principles calculations. Structural analysis discloses that the competition between the contraction effect from the bond length/angle shrinkage and the expansion effect from the angle closing between O-Ag-O bars and the (a, a , b ) plane dominates the occurrence of ZAC/NAC, and the framework openness governs the competing balance in this system. This work deepens the understanding of "wine-rack" models and enriches the NAC/ZAC family.

Hybrid organic-inorganic metal halide (OIMH) perovskites are regarded as potential photoluminescent (PL) materials and have attracted intensive attention. Here, we select 1-methylpiperazine as an organic component and successfully obtain a two-dimensional (2D) Ge-based OIMH perovskite, (1-mpz)GeBr4. It features a 2D layered structure composed of distorted [GeBr6]4- octahedra with organic (C5H14N2)2+ located between the layers. (1-mpz)GeBr4 exhibits strong orange color under ultraviolet (UV) light and possesses good PL stability for over 2 months. The photoluminescence quantum efficiency is measured to be 7.15% at room temperature, which is the largest among all reported low-dimensional Ge-based perovskites. Experimental measurements, combined with first-principles calculations, reveal that its PL property is attributed to self-trapped excitons (STEs) from [GeBr6]4- groups. From the deduced structure-property relationship, Ge-based OIMH PL perovskites with good stability and high PL efficiency can be expected.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

新时代背景下,研究生导师立德树人还存在认同感与获得感缺失、思政育人方法与途径不足等问题.针对上述问题,文章对研究生导师立德树人的实现途径进行了深入探索与研究.首先提出了以思政要素为导向、科研项目为载体的研究生多维、多元协同科研思政培养模式,并深入剖析了其内涵,从导师自我提升、多元协同工作和校友返校等方面阐述了科研思政机制建设方法,最后对研究生立德树人实践效果进行了评价.

The strong mutual coupling of and even the opposite change in the key parameters, such as the band gap ( E g ) and second-order harmonic generation (SHG), leads to the extreme scarcity in high-performance IR nonlinear optical (NLO) chalcogenides. Herein, we report 8 new sulfides, Na 2 Ba[(Ag x Na 1− x ) 2 Sn 2 S 7 ] ( 1 , x =0; 1   series , x =0.1–0.6; Na 2 Ba[(Li 0.58 Na 0.42 ) 2 Sn 2 S 7 ], 1-0.6Li ); Na 2 Sr[Cu 2 Sn 2 S 7 ] ( 2 ); and Na 2 Ba[Cu 2 Sn 2 S 7 ] ( 3 ). We use the structural tolerance factor ( ) to connect the chemical composition, crystal structure, and NLO properties. Guided by these correlations, a better balance between E g and SHG is realized in 1 , which exhibits a large E g of 3.42 eV and excellent NLO properties (SHG: 1.5×AGS; laser-induced damage threshold: 12×AGS), representing the best performance among the known Hg- or As-free sulfides to date.

Negative area compressibility (NAC) is a counterintuitive 'squeeze-expand' behavior in solids that is very rare but attractive due to possible pressure-response applications and coupling with rich physicochemical properties. Herein, NAC behavior is reported in palladium diselenide with a large magnitude and wide pressure range. We discover that, apart from the rigid flattening of layers that has been generally recognized, the unexpected giant NAC effect in PdSe2 largely comes from anomalous elongation of intralayer chemical bonds. Both structural variations are driven by intralayer-to-interlayer charge transfer with enhanced interlayer interactions under pressure. Our work updates the mechanical understanding of this anomaly and establishes a new guideline to explore novel compression-induced properties.

In the era of smart grids and the Internet of Things, demand side management, which aims to reduce electricity bills while increasing user satisfaction by scheduling appliances properly, becomes imperative for residential consumers. As a result of the conflict between the two objectives, it is impossible to optimize them simultaneously. Nevertheless, using multi-objective optimization approaches, trade-off solutions can be obtained. In this paper, a novel demand-side management method is presented to manage the operation of residential appliances. In the beginning, appliances are divided into interruptible, non-interruptible, and power-shiftable types according to their operating characteristics and the user’s preferences. And the mathematical models are built accordingly. Then, a multi-objective optimization problem is formulated to minimize the electricity cost and user dissatisfaction, in which residents’ tolerance to discomfort is considered. Since it is a multi-objective mixed integer nonlinear programming problem, a hybrid meta-heuristic algorithm is proposed to solve it efficiently. The experiment results have confirmed the effectiveness of the optimization model and the higher efficiency of the hybrid algorithm. Furthermore, a case study has been performed to demonstrate the effectiveness of the scheduling method.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Under cold pressure sp 1 /sp 2 -to-sp 3 hybridization transformation has been exclusively observed in covalent or molecular crystals overwhelmingly above ≈10 GPa, and the approaches to lower the transition pressure are limited on external heat-treatment and/or catalyzers. Herein we demonstrate that, by internal-lattice stress-transfer from ionic to covalent groups, the transformation can be significantly prompted, as shown in a crystal of LiBO 2 under 2.85 GPa for the first case in ionic crystals. This unprecedentedly low transformation pressure is ascribed to the enhanced localized stress on covalent B−O frames transferred from ionic Li−O bonds in LiBO 2 , and accordingly the corresponding structural feature is summarized. This work provides an internal structural regulation strategy for pressure-reduction of the s-p orbital hybridization transformation and extends the sp 1 /sp 2 -to-sp 3 transformation landscape from molecular and covalent compounds to ionic systems.

This paper proposes a 3D reconstruction method for the cross-scale narrow space containing thin structure. This method takes monocular image sequences as input and respectively constructs large-scale scene point cloud of main part based on incremental SfM and small-scale thin structure point cloud based on the curve method. The small-scale thin structure point cloud reconstructed individually alleviates the defect of incomplete point cloud from the large-scale scene. By introducing PCA for initial registration, alternatively iterating the closest point algorithm and the global optimization algorithm, we achieve a more precise registration for the thin structure point cloud. Then, a replacement algorithm is used to fuse it with the point cloud of the main part. The experiment containing two scenes verifies the effectiveness of our method, which reconstructs point cloud of the thin structure with high accuracy and retains the overall 3D information of the scene at the same time.

Negative thermal expansion (NTE), violating thecommon sense of"thermal expansion and cold contraction"effects,is a novel temperature-responding behavior of great scientific andtechnical significance. Herein, we report a two-dimensional (2D)NTE behavior in a crystal of LiBO2, which is constructed bygraphite-like [LiBO2]infinity layers. This intriguing thermal propertyoriginates from the synergistic effect of the distortion of in-plane[LiO3] bases in [LiO4] tetrahedra and the rotation of [BO3]triangles in the [LiBO2]infinity layer, driven by the force perpendicular tothe layer owing to the large interlayer separation as temperatureincreases. Remarkably, the in-plane and out-of-plane Li-O bondswithin the [LiO4] tetrahedra have nearly the same bond strengthand exhibit the similar variation with respect to temperature, andthis is quite different from the common sense on the 2D NTEbehavior in layered structures that the intralayer atomic interaction must be much stronger than the interlayer ones. Our studydeepens the understanding of the 2D NTE mechanism and would promote the exploration for NTE materials.

结合普通纸笔交互方式对纸张检测的实时性和鲁棒性的要求,提出了一种基于边缘检测的快速纸张检测方法.在边缘检测阶段,提出了跨层特征融合的快速纸张边缘检测方法.在HED主干网上添加线性瓶颈逆残差块和融入高效通道注意力的B-ECA块,大幅度减少了参数量,增加了显著特征的权重;分阶段融合各阶段各层特征,保留了更多的边缘特征;对高阶段特征上采样,并与低阶段特征进行跨层特征融合,解决了边缘模糊的问题.在自建的MPDS数据集上进行训练和测试,相较于HED方法,提出的纸张边缘检测方法在ODS和OIS指标上分别提高了8.1％和6.6％,检测速度由22.08 fps提高到了39.02 fps.在纸张提取阶段,提出了基于纸张结构约束的纸张提取方法.依次对纸张边缘进行基于非极大值抑制的边缘细化、直线检测与筛选、结构约束的纸张顶点提取,最终提取出只包含纸张的图像.实验结果表明,在各种复杂桌面环境及遮挡情况下,提出的纸张提取方法均可以快速、准确地提取完整的纸张图像,可以为普通纸笔交互方法提供交互基础.

With the increasing of intelligence and interactivity of vehicles, the navigation system become an indispensable component. Since current available navigation systems may lead drivers’ attention distracted, a novel AR HMD (Head-Mounted Display) navigation system is proposed, which relies on HoloLens2, integrating virtual-real fusion with eye tracking capability to analyze the relationship between the driver’s gaze behaviour and the driving scenario. To analysis the influence from navigation on driver’s attention, a new metrics with five indicators is designed. The experiments versify that the proposed AR navigation system can effectively avoid driver’s distraction and improve driving service level.