课程文献中心 更多>>

关键词： Cathodic arc evaporation   Hardness   Machine learning   Microstructure   Physical vapor deposition (PVD)   Scratch test   Ti-Al-Nb-N  

摘要： Understanding the relationship between chemical composition, process parameters, and their impact on titanium-based physical vapor deposition (PVD) coatings – such as titanium nitride (TiN), titanium niobium nitride (TiNbN), and titanium aluminum nitride (TiAlN) – remains a key challenge in advancing arc PVD coating technologies for industrial applications. Building on the promising performance of Ti_1-x-yAl_xNb_yN reported in previous studies, this study aimed to evaluate the impact of process bias on Ti_1-x-yAl_xNb_yN coatings with varying chemical configurations.

关键词： Morphing Wings   Spanwise Travelling Waves   Turbulence   Shear Layers   High-Fidelity numerical simulations   Aerodynamic Performance  

摘要： The effect of spanwise travelling wave (STW) morphing applied in the near trailing edge region of wings is investigated through High-Fidelity numerical simulations. This concept is part of the bioinspired electroactive morphing wings studies conducted in the context of the European research project HORIZON 2023–2027 PATHFINDER N°101129952 BEALIVE (“Bioinspired Electroactive Aeronautical multiscale LIVE-skin”). The numerical simulations were performed with the Navier-Stokes Multi Block (NSMB) solver, using the Arbitrary Lagrangian Eulerian (ALE) method to account for the moving and deforming grid. The Organised Eddy Simulation (OES) turbulence modelling was employed to capture the dynamics of coherent structures. The configuration studied corresponds to an A320 wing in the low subsonic regime, with a chord of $\mathit{70 cm}$, a span of $\mathit{60 cm}$, a Mach number of $\mathit{0.063}$, an incidence of

来源 ScienceDirectJournal 详细信息

关键词： Spinal cord injury   Brain extracellular matrix hydrogel   Neural stem cells   Melatonin   AMPK signaling  

摘要： Spinal cord injury (SCI) results in severe and debilitating neurological damage. Mitochondria play a crucial role in the differentiation of neural stem cells (NSCs) and neural regeneration. However, mitochondrial dysfunction occurs following SCI, manifesting as dysregulation of oxidative stress and ATP depletion, which impede neural regeneration. In this study, we developed a multi-functional, injectable hydrogel platform by integrating a brain-derived extracellular matrix (BEM), the neuroprotective agent melatonin (MT), and NSCs. We hypothesized that this NSCs@MT/BEM system would create a synergistic niche in which BEM provided tissue-specific signals, and melatonin metabolically reprogramed NSCs to enhance the regenerative potential. In vitro, melatonin directed NSCs differentiation towards a neuronal fate by enhancing mitochondrial function through AMPK signaling. When transplanted into a rat model of thoracic spinal cord contusion, the NSCs@MT/BEM hydrogel elicited robust functional recovery, evidenced by significantly improved Basso-Beattie-Bresnahan (BBB) scores, restored gait patterns, and enhanced electrophysiological conduction. This functional repair was supported by profound structural changes: enhanced survival of transplanted NSCs, preserved host neurons, attenuated glial scarring, and robust serotonergic axon regeneration across the lesion. Our findings demonstrated that a strategy combining a biomimetic scaffold with targeted metabolic modulation created a pro-regenerative microenvironment, significantly enhancing the therapeutic efficacy of NSCs transplantation for SCI repair.

关键词： Almost-anoxic PAHs bioremediation   Phenanthrene biodegradation   Denitrification   Carbon mineralization   Bioemulsifier   Metabolic process  

摘要：

• •
  Strain YWX-1 biodegraded phenanthrene and mineralized CO₂ synchronously.
• •
  The biodegradation was driven by oxygen reduction and partial denitrification.
• •
  Carbonic anhydrase and partial denitrification promoted carbon mineralization.
• •
  Bioemulsifier enhanced phenanthrene solubility and carbon mineralization.
• •
  The process of phenanthrene biodegradation and carbon mineralization was proposed.

关键词： Dielectric loss   Inelastic neutron scattering   Perovskite   Phonon   STEM   Thermal conduction  

摘要： Ba(Mg_1/3Ta_2/3)O₃ (BMT) is a promising microwave dielectric material for 5 G resonator applications owing to its exceptionally high Q×f value exceeding 300 THz. In this study, the temperature dependence of the dielectric loss (tan δ) previously reported for BMT, was reanalyzed using inelastic neutron scattering data, the temperature dependence of thermal conductivity, and microstructural observations of domain boundaries. The temperature dependence of tan δ was separated into a temperature‑proportional term and a Debye‑type relaxation term. The former analysis revealed that BMT possesses an exceptionally small third‑order lattice‑energy term. Electron‑density distributions derived from synchrotron radiation X-ray diffraction and maximum-entropy-method analysis indicate a highly localized electron distribution around Ta ions, which is inferred to suppress lattice anharmonicity and thereby reduce dielectric loss. The latter analysis showed that the Debye relaxation originates from structural motifs associated with domain boundaries. This interpretation is further supported by the absence of relaxation behavior in BMT ceramics sintered in a nitrogen atmosphere, in which domain boundaries are significantly reduced and relaxation behavior is absent. These results clarify the intrinsic mechanisms governing dielectric loss in BMT and provide guidance for further loss reduction through microstructural control.

关键词： Digital-to-analog converter (DAC)   Non-return-to-zero (NRZ)   Power efficiency   Pulse amplitude-modulation 4-level (PAM-4)   SerDes   Serialization   Wireline transmitter  

摘要： This paper presents a 128 Gb/s PAM-4 wireline transmitter implemented in 22 nm CMOS. To address the inherent trade-offs between speed and power in the final serialization stage of quarter-rate architectures, a passive 4:1 multiplexer (MUX) based on capacitive charge redistribution is proposed. Unlike conventional designs, the proposed MUX eliminates static power consumption while maintaining sufficient operating speed for high-rate operation. It also avoids the need for complex control signaling, further simplifying the design. A comprehensive analysis of the trade-offs between output swing and operating speed is provided, and an optimal design point is identified. A 128 Gb/s PAM-4 transmitter incorporating the proposed passive MUX is implemented. Post-layout simulation results demonstrate that the transmitter achieves an energy efficiency of 0.89 pJ/bit with a 1 V_ppd output swing. These results validate the potential of passive charge-redistribution techniques for high-speed, energy-efficient wireline links.

关键词： 3,4-Dihydroquinazolin-2(1H)-Ones   5+1 annulation   Amines   Aryl isocyanates  

摘要： A [5 + 1] annulation tandem cycloaddition strategy of aryl isocyanates and amines has been developed and affords 3,4-dihydroquinazolin-2(1H)-one derivatives through the formation of new C–C and C–N bonds under mild conditions. The protocol displays broad substrate scope, high functional group tolerance, mild reaction conditions and is applicable on gram scale as well as to the concise synthesis of other functionalities analogue.

关键词： WN   Phase composition   XPS   Peak fitting   Chemical bonding  

摘要： The reliability of XPS spectra interpretation of heterogeneous materials exhibiting compositionally-driven phase transformations is shown to improve by a comprehensive sample analysis including characterization of microstructure, elemental composition, impurity level, and phase constitution. This approach is demonstrated here for a series of W_1-xN_x films with N content varying in the range 0 ≤ x ≤ 0.65, which results in a complex evolution of W 4f spectra. The reliability of peak models is further enhanced by performing self-consistent XPS analysis from all major core level spectra (W 4f, N 1s, O 1s, and C 1s) in liaison with XRD (for crystalline phase content, lattice parameters, preferred orientation), ToF-ERDA (elemental composition, impurity levels), SEM and TEM (micro- and nano-structural analysis), and SAED (crystalline content down to the nm-level). It is thus found that a phase transformation occurs as x increases from bcc α-W(N) with x = 0.06 to bcc α-W(N) + cubic β-W_yN (0.08 ≲ x ≲ 0.27), cubic β-W_yN + hexagonal W₂N₃ (0.36 ≲ x ≲ 0.56), and finally to cubic β-W_yN + amorphous WN₂ (0.62 ≲ x ≲0.65). The comparison of spectra recorded before and after Ar⁺ etching reveals that sensitivity to sputter damage varies greatly between different phases. This integrated methodology is particularly valuable for transition metal nitrides, carbides, and related compounds exhibiting continuous structural evolution with overlapping XPS signatures.