The development of electronic technologies capable of withstanding high-energy cosmic radiation is urgently needed to enable scientific exploration in increasingly extreme application scenarios, such as nuclear facilities, deep-space missions, and orbiting space stations. Conventional silicon-based integrated circuits (ICs) typically require additional radiation-hardening processes after design, resulting in structures that are more complex than standard devices. Moreover, many standard silicon-based ICs remain susceptible to total ionizing dose (TID)-induced degradation without dedicated hardening, leading to limited radiation tolerance. Consequently, the development of new materials, devices, and ICs with intrinsic radiation tolerance has emerged as a critical research frontier in recent years. Single-walled carbon nanotubes (SWCNTs) offer significant inherent advantages over conventional silicon-based technologies owing to their strong sp2 carbon-carbon bonds, one-dimensional quantum confinement, and minimal charge-trapping interfaces. This Review highlights the progress made at the Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), in the development of semiconducting SWCNTs (sc-SWCNTs) as well as radiation-hardened SWCNT field-effect transistor (FET) devices and ICs. In this field, researchers at SINANO have also authored several books on carbon-based electronic materials, devices, and circuits, alongside publishing more than 200 papers and being granted more than 50 patents. Specifically, this Review covers the purification of sc-SWCNTs and single-chirality sc-SWCNTs by both commercial and self-designed conjugated organic compounds; the deposition of high-quality networked and aligned sc-SWCNT thin films on flexible and rigid substrates; and the design and fabrication of record-performance radiation-hardened SWCNT FET devices and ICs. Finally, the remaining challenges in sc-SWCNT materials, FET devices, and ICs for reliable radiation-hardened applications are discussed, followed by perspectives on future practical deployment in space and other nuclear extreme environments.
The synthesis and characterization of an 18-atom tetra-benzimidazolylidene macrocycle, Me,EtTCB (1), and the corresponding tetranuclear silver transmetallation reagent, [(Me,EtTCB)2Ag4(NCCH3)2](PF6)4 (2), are reported. Transmetallation reactions between the silver complex and first-row transition-metal iodide salts provide Fe(II), Co(II), and Ni(II) complexes. Single-crystal X-ray diffraction reveals that the tetracarbene ligand enforces distinct coordination geometries across the metal series, giving octahedral Fe(II) (3), square pyramidal Co(II) (4), and square planar Ni(II) (5) complexes. Downfield shifts in carbene 13C NMR spectra relative to analogous tetra-imidazolylidene systems indicate diminished σ-donor strength for benzimidazolylidene donor groups. Cyclic voltammetry experiments show substantial anodic shifts in the M(II/III) redox couples (ΔE1/2 = 0.36-0.38 V) relative to Me,EtTCPh analogues, consistent with stabilization of the metal d-orbital manifold. Density functional theory calculations support these experimental observations and indicate that benzimidazolylidene tetracarbene 1 generates a strong equatorial ligand field while providing reduced σ-donation compared to related tetra-imidazolylidene macrocycles. Chemical oxidation reactions afforded {FeNO}6 (6), Fe(III) (7), and Co(III) (8) macrocyclic tetracarbene complexes. These findings demonstrate that modification of macrocyclic tetra-NHC donor frameworks can significantly influence the electronic structures and redox properties of late first-row transition metal complexes.
Developing highly efficient photothermal catalyst for N2-to-NH3 conversion remains a great challenge. Here we report atomically dispersed cobalt on niobium oxide (Co-Nb2O5) for NH3 synthesis through a photothermal NH coupling mechanism. This catalyst exhibits 28-fold enhancement in the rate of NH3 formation (14 mmol.g-1.h-1) over pristine Nb2O5 (0.46 mmol.g-1.h-1). The mechanistic study reveals that under photothermal stimulation, photoexcited Co 3d orbitals donate electrons into the π* antibonding orbitals of adsorbed N2, weakening the NN bond and enabling stepwise hydrogenation while reducing the apparent activation energy by more than 50%. Complementary DFT calculations and in-situ spectroscopies reveal that Co sites stabilize key intermediates along the associative distal pathway. These findings manifest single-atom coordination chemistry to control molecular activation and multi-electron transformations for solar-driven nitrogen fixation.
This study confirms the presence of accessory foramina in the orbito-sphenoid region, reinforcing their potential impact on neurovascular injury and surgical outcomes. Continued data collection will enhance accuracy and generalizability, emphasizing the need for presurgical visualization to optimize patient safety and surgical success. This study examined variations in the orbito-sphenoidal region using donor skulls (n=10) from A.T. Still University's Gift of Body Program. Careful dissection exposed the optic canal and superior orbital fissure, and cranial variations were analyzed. Three donor skulls exhibited accessory foramina: two with bilateral accessory foramina and one with a single foramen in the left orbit. Foramina diameters ranged from 0.687 mm to 1.204 mm, with a mean of 1.015 mm. These findings suggest that cranial remodeling often results in variations such as accessory foramina, emphasizing the importance of preoperative visualization to reduce the risk of neurovascular damage. Further research in larger, more diverse populations is needed to better understand the clinical implications of these variations. This study confirms the presence of accessory foramina in the orbito-sphenoid region, reinforcing the need for presurgical visualization to minimize neurovascular risks. Continued research will improve accuracy and generalizability, aiding in safer surgical planning.
Access to the orbit, cavernous sinus, Meckel cave (MC), and infratemporal fossa (ITF) remains challenging due to the complex 3-dimensional anatomy and proximity to critical neurovascular structures. An extradural endoscopic orbitozygomatic (OZ) approach has the potential to provide a direct surgical corridor across these compartments while minimizing the limitations of compartment-specific corridors. Five formalin-fixed, silicone-injected cadaveric heads (10 sides) were dissected using an extradural OZ approach under operative microscopy supplemented with 0° and 30° rigid endoscopes. After a two-piece OZ craniotomy, extradural dissection was performed toward the superior orbital fissure and foramen rotundum/ovale, combined with anterior petrosectomy and opening of MC. Anatomic exposure, corridor continuity, and visualization of key neurovascular structures were qualitatively assessed. The extradural endoscopic OZ approach created a direct working corridor from the lateral orbit to the ITF and petroclival region. Endoscopic augmentation enhanced visualization of the lateral cavernous sinus wall, trigeminal divisions (V1-V3), cavernous internal carotid artery, medial orbital apex, deep infratemporal recesses, and the petroclival region. Anterior petrosectomy extended exposure toward the upper clivus and ventrolateral brainstem. Limitations included restricted microscopic visualization of the medial orbit and inferior ITF, which were partially mitigated by angled endoscopy. This cadaveric study demonstrates that the extradural OZ-anterior petrosectomy approach establishes a continuous anatomic corridor integrating the orbit, cavernous sinus/MC, ITF, and petroclival region, while defining its boundaries, areas of optimal exposure, and inherent limitations. As a qualitative study, the findings are descriptive in nature and do not include quantitative morphometric analysis.
Spin-orbit torque (SOT) provides an efficient route for ultrafast and energy-efficient magnetization control in spintronic devices. However, deterministic switching of perpendicular magnetization in conventional non-magnet/ferromagnet bilayers is fundamentally limited by symmetry, typically necessitating an external magnetic field. In this work, we demonstrate unconventional spin currents and associated SOTs in antiferromagnet (AFM)-based NiO(110)/Ta/CoFeB/MgO trilayers, enabling nearly complete field-free switching of perpendicular magnetization. We find that the switching efficiency is maximized when the applied current is oriented transverse to the AFM easy axis, indicating that the generated spin currents are governed by the relative orientation between the Néel vector and the current direction. Second-harmonic measurements reveal angle-dependent spin currents with both in-plane and out-of-plane spin polarizations, which is consistent with micromagnetic simulations incorporating the Néel-vector dynamics in the AFM layer. Our findings suggest that AFM-based trilayers offer a versatile platform for efficient field-free switching and highlight the potential of Néel-vector-dependent spin currents for SOT-based spintronic applications.
The NASA Rodent Habitat aboard the International Space Station enabled long-duration studies of behavioral responses to spaceflight, but video-based behavioral analysis has relied on laborious manual annotation. No study has tested whether deep learning tools can automate this analysis under the demanding imaging conditions of orbital vivaria. We applied pose estimation (SLEAP) and behavioral segmentation (DeepEthogram) to archival footage from the Rodent Research-1 mission. Nine labelers annotated 3,249 pose labels across 2,063 frames, and three behaviorists labeled 411,194 frames across 66 videos. Pose tracking accuracy approximated human inter-annotator variability despite progressive lens soiling, grid occlusions, and spherical aberration. Behavioral classification across eight categories achieved accuracy of 0.86-0.90 and suggests progressive behavioral adaptations to microgravity. Kinematic reconstruction of circling estimated centripetal accelerations periodically approaching 1 g . This is the first application of deep learning-based pose estimation and behavioral segmentation to rodents in spaceflight, establishing benchmarks for future monitoring systems. Deep learning-based pose estimation and behavioral segmentation of ISS video reveal progressive behavioral adaptations of mice to microgravity.
The conventional framework for chemical bonding between main-group elements involves separate σ and π orbitals to describe multiple bonds. However, relativistic effects mix these orbitals in molecules containing heavy elements through spin-orbit coupling, leaving the total angular-momentum projection (ω) as the only good quantum number. Direct experimental evidence that relativistic effects change the σ-π bonding framework has remained elusive. Here, we probe the carbon-bismuth triple bond in the CBi- anion using high-resolution cryogenic photoelectron spectroscopy, coupled with relativistic four-component Dirac-Coulomb coupled-cluster calculations. Even though the CBi- anion is isovalent to the well-known CN- species, we demonstrate that the traditional σ + 2π triple-bond picture collapses into a pure π-like |ω| = 3/2 and two |ω| = 1/2 Kramers pairs containing substantial σ/π mixing.
Osteoporotic fractures are weight-bearing skeleton fractures resulting from minor trauma, and can be influenced by osteoporosis, a systemic condition that can impact fracture outcomes from severe events. To detect the prevalence of osteoporosis in the maxillofacial region and its association with the impact of maxillofacial trauma. To evaluate and assess the bone density of the maxillofacial region between different age groups and to assess the relationship between bone density and the occurrence of facial fractures in patients with maxillofacial trauma. A cross-sectional observational study was conducted on patients with a maxillofacial trauma history. Computed tomography (CT) examinations were performed using a 160-slice CT and picture archiving and communication system, with a minimum sample size of 74. The study used SPSS software to analyze data on various fracture sites, including continuous variables like orbital floor, nasal bone (NB), and zygomatico-maxillary suture, and categorical variables like fracture score distribution and grayscale categories by inter- and intragroup comparisons. There was an increased prevalence of osteoporosis and maxillofacial fractures in males, between the age group of 26-35 years in the subjects. Additionally, the osteoporotic bone showed reduced Hounsfield unit value and a coarser trabecular pattern on CT scans. This study thus proved the direct and specific effects of osteoporosis in the maxillofacial region using CT measures and also proved that they could be fractured at ease.
We present an efficient implementation of a one-step relativistic second-order multireference perturbation theory based on the multireference driven similarity renormalization group (MR-DSRG) using the exact two-component (X2C) Hamiltonian, which we denote X2C-DSRG-MRPT2. We show that the X2C-DSRG-MRPT2 method can accurately capture spin-orbit coupling (SOC) effects in the electronic structure of strongly correlated systems containing elements across the periodic table. We further demonstrate that the X2C-DSRG-MRPT2 method, through its variational treatment of SOC effects, can yield spin-orbit splittings with mean absolute percentage errors consistently below 7% with respect to experimental values for systems containing up to sixth row elements. With its modest computational scaling (fourth power in system size for the perturbative step) and high accuracy, X2C-DSRG-MRPT2 provides a promising avenue for the routine treatment of relativistic effects in strongly correlated molecular systems.
This study addresses vibration control of a gradually varying-size beam supported manipulator system (VBSMS) under on-orbit assembly conditions, achieved by incorporating a nonlinear energy sink (NES) consisting of a cubic nonlinear spring in parallel with a linear spring. A dynamic model of the coupled system is developed, and the frequency and amplitude responses are obtained using the harmonic balance-alternating frequency/time (HB-AFT) method in conjunction with the arc-length continuation technique. A composite optimization objective is formulated, which considers both the suppression ratio of the maximum steady-state response and a supplementary indicator that evaluates the overall performance of the absorber by capturing the severity of the vibration amplification and the extent of the affected region. A parametric analysis was subsequently conducted, leading to the proposal of optimal design guidelines for the NES parameters. Focusing on the response amplitude over a selected frequency range, the analysis yields optimal design criteria that minimize the steady-state amplitude of the beam throughout the assembly process, thereby offering practical guidance for absorber design in VBSMS.
Ideal density-functional approximations (DFAs) should account for dynamic, static, and nondynamic correlation. While common DFAs struggle with the latter two, the Ziegler-Rauk-Baerends-Daul multiplet sum method (MSM) provides a pragmatic way to include static correlation. In this article, we use diagrammatic MSM density-functional theory (diag MSM DFT) using the two-orbital two-electron model to extend MSM DFT to include nondynamic correlation without relying on symmetry arguments. Building on previous formulations [Ponra et al., J. Chem. Phys. 159, 244306 (2023) and Casida et al., J. Chem. Phys. 162, 144317 (2025)] that lacked relaxation effects, this article incorporates relaxation via nonorthogonal configuration interaction. We demonstrate that this modified diag MSM DFT produces an accurate ground-state potential energy curve for lithium hydride, even at the ionic-to-open-shell-singlet avoided crossing characterized by significant charge transfer. This encouraging result suggests that the model can be extended to (at least) other singly and multiply bonded diatomic molecules, while providing insight into a novel way to include strong correlation in DFT.
The rational design of carborane-based second-order nonlinear optical (NLO) materials requires fundamental understanding of how distinct electronic interactions govern the first hyperpolarizability. Herein, a systematic DFT/TD-DFT investigation is performed on a series of chalcogen-functionalized closo-carborane derivatives to establish explicit structure-property relationships and to achieve a comparative understanding of how distinct bonding motifs-nonconjugation, σ-π conjugation, and intramolecular charge transfer (ICT)-affect the second-order NLO properties. Our results demonstrate that nonconjugated compound 1 exhibits a modest NLO response. In chalcogen-bridged monomers 2-4, σ-π conjugation significantly enhances hyperpolarizability through improved orbital delocalization and moderate ICT. Notably, dimer 5 achieves the largest first hyperpolarizability (βtot = 786.4 a.u.), owing to its relatively extended CT distance and highly asymmetric spatial charge separation. In contrast, dimers 6 and 7 show markedly lower NLO activity despite stronger ICT, due to their symmetric, convergent charge redistribution that cancels the net dipole moment change. These results reveal that optimal second-order NLO performance requires a synergy of extended conjugation, directional ICT, and asymmetric charge redistribution. The quantitative correlations between electronic descriptors (e.g., overlap integral Sr, CT distance D, charge separation t index, and etc.) and first hyperpolarizability provide a predictive framework for engineering high‑efficiency NLO chromophores in hybrid inorganic-organic architectures.
The development of efficient electrocatalysts for ambient ammonia synthesis is a key challenge for enabling sustainable nitrogen fixation. However, most reported single-atom catalysts (SACs) rely heavily on conventional transition metals, which limits the exploration of alternative active centers. In this work, first-principles calculations are employed to systematically investigate a series of rare-earth (RE) SACs, focusing on their stability, nitrogen reduction reaction (NRR) activity, reaction pathways, and selectivity. The results indicate that the alternating pathway is thermodynamically preferred for the NRR, and a volcano-type relationship is established between the limiting potential and the adsorption free energy of NNH*, identifying NNH* as an effective activity descriptor. Among the investigated systems, Ce-embedded phthalocyanine (Ce/PC) exhibits excellent stability, high NRR activity, and strong suppression of the competing hydrogen evolution reaction. Electronic structure analysis reveals that the interaction between Ce and the PC support is mainly governed by Ce-5d orbitals, while activation of the N2 π* antibonding orbital originates from charge transfer involving Ce-4f states. Moreover, axial Li coordination further enhances the catalytic performance of Ce/PC, reducing the limiting potential to -0.13 V. Overall, this study broadens the scope of SAC design beyond traditional transition metals and provides new insights into rare-earth-based catalysts for sustainable ammonia synthesis.
To investigate the regulatory effect and mechanism of nuclear fragile X mental retardation-interacting protein 1 (NUFIP1) on the apoptosis of dendritic cells (DCs) in septic mice. Nufip1+/- C57BL/6J mice were generated, and Western blotting was performed to verify the protein expression level of NUFIP1 in splenic DCs. A total of 48 SPF male wild-type (WT) mice and Nufip1+/- mice were divided into the sham group (18 mice) and the sepsis group (30 mice). Three independent replicate experiments were conducted, and mice were grouped using a random number table in each trial. The cecal ligation and puncture (CLP) procedure was performed to establish the sepsis model in the sepsis group; mice in the Sham group only underwent laparotomy and cecal separation without ligation. Twenty-four hours after operation, orbital blood was collected. The mice were then sacrificed, and heart, lung, liver, kidney tissues as well as spleens were harvested for isolation and extraction of splenic DCs. Flow cytometry was applied to detect the apoptosis rate of splenic DCs. Western blotting was used to determine the protein expression levels of apoptosis-related proteins including caspase-3, Bcl-2, heat shock protein 5 (HSPA5), eukaryotic translation initiation factor 2 alpha kinase 3 (EIF2AK3), phosphorylated EIF2AK3 (p-EIF2AK3), eukaryotic translation initiation factor 2A (EIF2A), phosphorylated EIF2A (p-EIF2A), activating transcription factor 4 (ATF4) and DNA damage-inducible transcript 3 protein (DDIT3) in splenic DCs. Enzyme-linked immunosorbent assay (ELISA) was adopted to detect the serum levels of interleukins (IL-2, IL-4, IL-10), transforming growth factor-β (TGF-β) and interferon-γ (IFN-γ). Hematoxylin-eosin (HE) staining was performed to observe the injury of heart, lung, liver and kidney under light microscope. The endoplasmic reticulum (ER) morphology of splenic DCs was observed under a laser confocal microscope. An additional 20 WT mice and 20 Nufip1+/- mice were respectively assigned to the sham group and sepsis group, with 10 animals in each subgroup. The 7-day survival rate after CLP was observed in all groups. Western blotting results showed that the protein expression level of NUFIP1 in splenic DCs of Nufip1+/- mice was lower than that of WT mice (NUFIP1/β-actin: 1.080±0.233 vs. 2.178±0.440, P<0.05), indicating the successful construction of NUFIP1 gene-deficient mice. Flow cytometry results revealed that the apoptosis rate of splenic DCs at 24 h after CLP in the Nufip1+/- sepsis group was higher than that in the WT sepsis group [(43.41±1.70)% vs. (30.43±4.99)%, P<0.05]. Meanwhile, compared with the WT sepsis group, the protein expression level of caspase-3 in splenic DCs was increased, while the protein expression level of Bcl-2 was decreased in the Nufip1+/- sepsis group (caspase-3/β-actin: 1.23±0.17 vs. 0.59±0.14, Bcl-2/β-actin: 0.46±0.13 vs. 0.72±0.08, all P<0.05). Compared with the WT sepsis group, the serum levels of IL-2 and IFN-γ in the Nufip1+/- sepsis group were decreased [IL-2 (ng/L): 8.54±0.27 vs. 209.70±1.56; IFN-γ (ng/L): 391.60±9.24 vs. 512.70±31.50, all P<0.05], whereas the serum levels of IL-4, IL-10 and TGF-β were increased [IL-4 (ng/L): 73.19±2.38 vs. 28.52±0.98; IL-10 (ng/L): 359.20±2.02 vs. 267.60±5.05; TGF-β (ng/L): 826.20±26.73 vs. 497.30±3.33, all P<0.05], and the IFN-γ/IL-4 ratio was decreased (7.98±0.46 vs. 16.59±0.40, P<0.05). These findings suggested that peripheral immunosuppression was further aggravated in Nufip1+/- mice during sepsis relative to WT mice. HE staining demonstrated that the injury of heart, lung, liver, kidney and other tissues in the Nufip1+/- sepsis group was markedly severer than that in the WT sepsis group, and the 7-day survival rate was lower in Nufip1+/- mice [20% (2/10) vs. 50% (5/10), P<0.05). Compared with the WT sepsis group, the protein expression levels of HSPA5, the ratio of p-EIF2AK3 to EIF2AK3, the ratio of p-EIF2A to EIF2A, ATF4 and DDIT3 in splenic DCs after CLP were all up-regulated in the Nufip1+/- sepsis group (HSPA5/β-actin: 0.93±0.38 vs. 0.34±0.02, p-EIF2AK3/EIF2AK3 ratio: 1.67±0.28 vs. 0.59±0.05, p-EIF2A/EIF2A ratio: 0.90±0.09 vs. 0.61±0.08, ATF4/β-actin: 1.71±0.77 vs. 1.60±0.48, DDIT3/β-actin: 1.18±0.12 vs. 0.56±0.34, all P<0.05). Laser confocal microscopy showed that the morphological changes of ER in splenic DCs of the Nufip1+/- sepsis group were more obvious than those in the WT sepsis group, presenting irregular distortion, swelling and fragmentation. NUFIP1 gene deficiency induces extensive apoptosis of splenic DCs in the early stage of sepsis, further aggravate peripheral immunosuppression, exacerbate multiple organ damage and worsen survival outcomes in septic animals.
This study examines the modular organization of the human skull and variation in cranial integration across Eurasian populations. The study analyzed 450 male crania from 10 Eurasian populations using 35 craniometric variables. Correlation matrices were constructed and evaluated using EMMLi analysis and the covariance ratio (CR) to test alternative modularity models, while two-block partial least squares (2B-PLS) analysis was used to estimate the strength of cranial integration. EMMLi and CR analyses supported a highly modular organization of the human skull, with generally weak correlations within and between cranial modules. Viscerocranial modules showed stronger internal integration than neurocranial modules. Asian populations displayed weaker intermodular correlations, especially in the orbital and zygomatic regions, suggesting greater independence of these traits. The Khanty sample occupied an intermediate position between major macroregional groups. Increased cranial integration was observed in island and peripheral populations. The findings indicate that weak integration among cranial modules may increase the potential for craniofacial variation in humans. Reduced integration of orbital and zygomatic modules in North Asian populations may reflect climatic adaptation and/or high population mobility. Lower modularity in island populations may result from stronger genetic drift or stabilizing selection, whereas increased modularity may reflect directional selection. Cranial modularity varies not only among species but also among modern human populations, reflecting microevolutionary processes and environmental influences on morphological diversity.
IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder characterized by complex immune-mediated mechanisms and broad organ involvement that remains substantially underdiagnosed in clinical practice. The head and neck region is one of the most commonly involved anatomical domains, encompassing the major salivary glands, lacrimal glands, nasal cavity and paranasal sinuses, larynx and subglottis, thyroid gland, middle ear, orbit, and cervical lymph nodes. This review integrates current understanding of the immunopathological mechanisms underlying IgG4-RD with organ-specific clinical features and therapeutic considerations across these head and neck subregions. The core immune pathogenesis involves clonally expanded CD4+ cytotoxic T lymphocytes and activated follicular helper T cells that, within a Th2-skewed cytokine environment, promote IgG4 class-switch recombination and plasmablast expansion, driving the transition from inflammatory infiltration to progressive fibrotic remodeling. Although head and neck subtypes share this common immunopathological framework, they differ considerably in the relative balance between inflammatory and fibrotic features, clinical severity, and organ-specific risk profiles. These differences may reflect local microenvironmental factors, including epithelial characteristics, innate immune responsiveness, and the functional properties of resident stromal fibroblasts, though the precise mechanisms remain to be fully established. Therapeutically, glucocorticoids remain the standard first-line treatment for remission induction but are limited by high relapse rates after withdrawal. Rituximab has demonstrated efficacy in refractory and relapsing disease. Inebilizumab, an anti-CD19 monoclonal antibody, has shown significant benefit in a phase III randomized controlled trial. Dupilumab, which targets the IL-4/IL-13 signaling axis, has shown potential in case reports and small series, but prospective validation is required before it can be recommended as a standard therapeutic option. By mapping organ-specific immunopathological differences onto differentiated therapeutic approaches, this review aims to support a more individualized, biologically informed framework for managing IgG4-RD in the head and neck.
Continuous time-translation symmetry is often spontaneously broken in open quantum systems, and the condition for their emergence has been actively investigated. However, there are only a few cases in which its condition for appearance has been fully elucidated. In this Letter, we show that a Lindbladian parity-time (PT) symmetry can generically produce persistent periodic oscillations in a wide class of systems. This includes one-collective spin models, which have been studied thoroughly in the context of dissipative continuous time crystals, and spatially extended bipartite bosonic systems with a conserved particle number. By making an analogy to nonreciprocal phase transitions, we demonstrate that a transition point from the dynamical phase is associated with spontaneous PT symmetry breaking that typically corresponds to a critical exceptional point. Interestingly, the periodic orbits in the PT symmetric phase are found to be center type, implying an initial state dependence. These results are established by proving that the Lindbladian PT symmetry at the microscopic level implies a nonlinear PT symmetry and by performing a linear stability analysis near the transition point. This research will further our understanding of novel nonequilibrium phases of matter and phase transitions with spontaneous antiunitary symmetry breaking.
Cobalt (Co), a highly valuable transition metal with unique physical properties, has been widely used as a battery material and, significantly, it satisfies the demand for the rapid development of electric vehicles. However, the scarcity of available sources of Co2+ hinders its sustainable development and the extraction and recovery of Co2+ is facing severe challenges. Compared to traditional extraction processes, ionic liquids (ILs) have been widely studied as advanced solvents due to their excellent properties. In this study, we investigated the Co2+ extraction performance of several ILs, including tri(2,4-methylpentyl)phosphinate ([C8H17NH2][Cyanex272]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4MIM][NTF2]) with tributyl phosphate (TBP), [C4MIM]citrate ([C4MIM][C6H7O7]) with di(2-ethylhexyl)phosphoric acid (D2EHPA), 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF6]) with histidine-2-ethylhexylamide (H2EHA), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4MIM][NTF2]) and trioctyl phosphine oxide (Cyanex923). We found that the number of H2O molecules impacts the cluster structures, while the different types of ILs determine the Co2+ extraction efficiency. The extraction performance follows the order of [C4MIM][C6H7O7]/D2EHPA > [C8H17NH2][Cyanex272] > [C4MIM][NTF2]/Cyanex923 > [HMIM][PF6]/H2EHA > [C4MIM][NTF2]/TBP. The structures with the highest formation energy were selected for analysis of their intra-cluster interactions using an independent gradient model based on Hirshfeld partition (IGMH), electrostatic potential and Natural Bond Orbital (NBO) analysis. Unexpectedly, the extraction effects of five cluster structures on Co2+ were all better than those on Li+, indicating that the extraction performance of ILs significantly differs among different metals. Additionally, we found that the overall extraction efficiency of four ILs for extracting Co2+ and Li+ was identical, among which [C4MIM][C6H7O7 exhibited the best performance. Using the same IL [C4MIM][NTF2], we compared the extraction performance in different co-solvents, Cyanex923 and TBP, and found that Cyanex923 was more effective in extracting metal ions than TBP. This work provides theoretical evidence for the application of ILs in liquid-liquid extraction and for the design of highly efficient extractants in metal recovery.
Ab initio CASSCF/(MRCI + Q) calculations were employed to investigate the electronic structure of the AlCd molecule. The adiabatic potential energy curves of the low-lying doublet and quartet electronic states of AlCd were computed in both the 2S+1Λ(+/-) and Ω representations. The spectroscopic parameters T e, R e, ωe, B e, the dipole moment μe, and the dissociation energy D e were determined for the bound states of the molecule. Several new electronic states were characterized here for the first time. Rovibrational analysis of the ground and low-lying excited states was carried out using the canonical functions method to obtain the constants B v, D v, E v, R min, and R max. To assess the potential of AlCd for direct laser cooling, Franck-Condon factors were determined between the ground and low-lying excited states.