Surface-enhanced Raman scattering (SERS) spectroscopy has emerged as a powerful analytical technique for the sensitive detection of hazardous molecules, owing to its ultranarrow spectral linewidths and highly specific molecular fingerprinting capability. Herein, we designed a reliable SERS substrate consisting of polystyrene microspheres (PS), Ti3C2Tx MXene nanosheets, and Ag nanoparticles (NPs) for the sensitive detection of various organic pollutants. By integrating the photonic nanojet effect of PS, the charge transfer capability of MXene nanosheets, and the electromagnetic field enhancement induced by Ag NPs, the PS@MXene@Ag composite substrate exhibited outstanding SERS sensitivity, along with excellent reproducibility and signal uniformity. As a result, the limit of detection (LOD) for 2-mercaptopyridine (2-Mpy) was as low as 1.24 & times; 10- 12 M, with the SERS performance factor (SPF) of up to 5.0 & times; 107. Moreover, the SERS substrate maintained good stability after storage for four weeks. In addition, the PS@MXene@Ag composite was successfully applied to the detection of other organic pollutants, including thiram and methylene blue (MB). The calibration results revealed a good linear relationship between the logarithm of concentration and the corresponding SERS intensity, with correlation coefficients (R2) of 0.99 and 0.98, respectively. The LODs for thiram and MB were calculated to be 1.96 & times; 10-10 M and 2.33 & times; 10-10 M, respectively, and satisfactory recovery rates were obtained in practical sample analyses (orange peel and fish skin). These results demonstrate that the fabricated PS@MXene@Ag SERS substrate has promising potential for the detection of organic molecular pollutants.

Ferroptosis is a novel form of programmed cell death distinct from apoptosis, necrosis, and autophagy, characterized by the abnormal accumulation of iron-dependent lipid peroxides. Increasing evidence suggests that ferroptosis is widely involved in various diseases, including neurodegenerative disorders, cancers, and cardiovascular diseases. However, the mechanisms of enzymes promoting lipid peroxidation remain poorly understood. The endoplasmic reticulum monooxygenase (MMO) mainly composed of cytochrome P450 (CYPs) and cytochrome P450 reductase (CPR) transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH) to molecular oxygen, leading to the generation of reactive radical intermediates and hydrogen peroxide. Subsequently, peroxidation of unsaturated liposomes disrupts membrane integrity and leads to ferroptosis. Herein, we elucidate the molecular details of MMO-liposome interactions and reveal their association with phospholipid membrane permeabilization in ferroptosis. Using Raman spectroscopy, we found that MMO interacted with unsaturated liposomes in the presence of electron donors, disrupting the conformation order of fatty acid chains. Furthermore, the degree of unsaturation in the liposomes positively correlates with the extent of peroxidation. Simultaneously, through the Raman spectra of the CYP 3A4 redox center, the relationship between MMO-liposome interactions and reactive oxygen species (ROS) generation is revealed, providing new insights into the mechanistic analysis of MMO-mediated ferroptosis. Moreover, the addition of Fe3+ promotes the generation of reactive hydroxyl radicals, accelerating the extent of liposomal peroxidation. This study provides new mechanistic insights into how MMO promotes ferroptosis through lipid peroxidation and offers a theoretical basis for the development of novel anticancer therapeutic strategies.

Surface-enhanced Raman scattering (SERS) has emerged as a powerful analytical tool for trace molecular detection, enabling identification of target analytes through their characteristic vibrational fingerprints. Its high sensitivity, selectivity, and non-destructive detection capabilities make it extremely valuable in fields such as biological detection, food safety, and environmental detection. Currently, metal carbonitride (MXene) as an emerging two-dimensional material has become a hot topic in the field of SERS. In this work, by combining the advantages of bimetallic nanoparticles and MXene nanosheets, Ni/Ag nanoparticles with different proportions were modified on monolayer MXene nanosheets through chemical reduction and transmetallation reactions for the rapid detection of thiram. The evaluation of the SERS performance of the MXene-Ni/Ag composite substrate for the Raman reporter molecule mercaptobenzoic acid (MBA) demonstrates a high SERS performance factor (SPF) of 8.2 × 106, and a low detection limit of 10-10 M. Also, for the detection of the pesticide thiram, the substrate exhibits high sensitivity and reliable quantitative analysis capabilities, retaining detectable spectral features even at concentrations down to 10-9 M. Meanwhile, the substrate also exhibits a low relative standard deviation (RSD) value in reproducibility and maintains good stability over a certain period. Ni/Ag bimetallic nanoparticles provide high SERS activity, while MXene nanosheets effectively concentrate target molecules through their strong adsorption capacity. These results indicate that MXene-Ni/Ag composite substrates can serve as a highly effective SERS platform for sensitive and reliable environmental monitoring.

The limited deformation capacity at room temperature remains a significant challenge in refractory high-entropy alloys (RHEAs). In this study, the fine-grained Hf20Mo15Nb25Ta20-xTi20+x (x = 0, 5, 10, 15) alloys were prepared by mechanical alloying and subsequent spark plasma sintering (SPS), based on precise component regulation. The impact of altering the Ti/Ta ratio (R, R = (20+x)/(20-x)) on the pre-alloyed powders and the as-sintered alloys were investigated. An increase in R-value led to larger powder particle sizes and lower powder yields, which was attributed to the improvement in the plasticity of the pre-alloyed powders. After SPS sintering, the as-sintered alloys were comprised of two BCC solid solution matrices and nanoscale precipitated phases. As the R-value increases, the stability of the microstructure decreases slightly, while the yield strength shows a slight improvement, and the plastic strain experiences a relatively significant enhancement. The as-sintered Hf20Mo15Nb25Ta20-xTi20+x alloys all exhibited an excellent balance of strength and plasticity. Theoretical calculations revealed that the yield strength of the alloys was the result of the combined effect of several strengthening mechanisms, predominantly substitutional solid solution strengthening. Furthermore, a systematic discussion was conducted on the reasons for the improvement in the plasticity of the as-sintered alloys. This study presents an effective approach to enhancing the room temperature deformation capacity of RHEAs, thereby facilitating their broader application.

We demonstrate a large-mode-area erbium-doped waveguide amplifier based on the heterogeneous integration of $\text{Si}_{3}\mathrm{N}_{4}$ waveguide and $\text{Er}^{3+}:\mathrm{A}1_{2}\mathrm{O}_{3}$ film. It exhibits over 18 dBm on-chip output power at 1533 nm within an 8-cm-long waveguide.

This paper examines the solid-phase diffusion bonding (DB) of TiBw/Ti65 composites, focusing on the effects of processing parameters such as temperature, time, pressure, and interlayer thickness. The findings show that lower processing conditions resulted in slower atomic diffusion and more defects, whereas higher conditions reduced pores but led to grain growth. Optimal bonding was achieved at 950 degrees C, 10 MPa, and 60 minutes, yielding a shear strength of 686 MPa, which is 81.86 % of the base material's strength. The introduction of pure titanium interlayer results in a concentration gradient, which serves as an additional driving force for atomic diffusion, thereby enhancing the quality of diffusion bonding. Shear strength varied with interlayer thickness, peaking at 668 MPa for a 5 mu m interlayer. Microplastic deformation, dynamic recrystallization (DRX), and grain boundary (GB) migration affected the microstructure and mechanical properties of the bonding interface. TiB whiskers (TiBw) near the bonding interface significantly influenced DRX and GB migration during the DB process.

We present a novel and efficient methodology for obtaining high-gain on-chip few-mode erbium-doped waveguide amplifiers, which exhibit a moderate differential mode gain (DMG). The efficiency of the device is validated by an optimized algorithm that theoretically models the gain performance of the six lowest-order optical modes, namely TE0, TM0, TE1, TM1, TE2, and TM2. Notably, these six signal modes achieve internal net gains exceeding 22 dB within a 5-cm-long waveguide, while maintaining the DMG at a mere 2 dB. This DMG value represents a significant reduction of 5 dB compared to the non-optimized uniform doping configuration. Furthermore, a maximum saturated output power of 150 mW has been achieved. As a practical demonstration, we also propose a feasible fabrication process utilizing atomic layer deposition (ALD) along with standard complementary metal-oxide semiconductor (CMOS) techniques. These results demonstrate the superiority of our methodology in enhancing the performance of few-mode optical waveguide amplifiers.

A simple method for the fabrication of silver（Ag） nanosheet-assembled film on aluminum（Al） foil was demonstrated based on the Galvanic displacement reaction between Al and Ag + .In order to obtain Ag nanosheets with large area and high aggregation density, both F - and H + ions were introduced into the reaction system to etch the barrier layer Al 2 O 3 on Al foils and promoted the increasing of the number of Ag nuclei.Therefore, Ag nuclei grew into nanosheets with citrate ions as the shape control agent.By varying the reaction parameters, Ag nanosheet film were optimized for surface-enhanced Raman scattering（SERS） measurements.The Ag nanosheet film prepared by the presented method exhibit the advantages of controllable morphology, good SERS activity and distribution in large area, which can be utilized as a promising SERS-active candidate substrate for analytical applications.

The spin polarization of carbon nanomaterials is crucial to design spintronic devices. In this paper, the first-principles is used to study the electronic properties of two defect asymmetric structures, Cap-(9, 0)-Def [6, 6] and Cap-(9, 0)-Def [5, 6]. We found that the ground state of Cap-(9, 0)-Def [6, 6] is sextet and the ground state of Cap-(9, 0)-Def [5, 6] is quartet, and the former has a lower energy. In addition, compared with Cap-(9, 0) CNTs, the C adatom on C30 causes spin polarization phenomenon and Cap-(9, 0)-Def [6, 6] has more spin electrons than Cap-(9, 0)-Def [5, 6] structure. Moreover, different adsorb defects reveal different electron accumulation. This finding shows that spin polarization of the asymmetric structure can be adjusted by introducing adatom defects.

In this work, we demonstrate a simple method for the fabrication of silver (Ag) nanosheet-assembled film on aluminum (Al) foil based on the galvanic displacement reaction between Al and Ag+. In order to obtain Ag nanosheets with large area and high aggregation density, both F− and H+ ions were introduced into the reaction system to etch the barrier layer Al2O3 on Al foils and promote the increase of the number of Ag nuclei. Therefore, Ag nuclei grew into nanosheets with citrate ions as the shape control agent. By varying the reaction parameters, Ag nanosheet film was optimized for surface-enhanced Raman scattering (SERS) measurements. The Ag nanosheet film prepared by the presented method exhibit the advantages of controllable morphology, good SERS activity, and distribution in large area, which could be utilized as a promising SERS-active candidate substrate for analytical applications.

Superatom-assembled materials have highly tunable magnetic and electronic properties and parameters of clusters. Here, eight superatom dimers composed of two U@B40 motifs have been studied by the density functional theory. Calculation results show that U@B40 dimers exhibit spin antiferromagnetic coupling, spin ferromagnetic coupling and nonmagnetic, that is, the magnetic coupling is induced by the interaction between the U@B40 superatoms. In addition, the monomers in U@B40 dimers still retain the superatomic orbitals, and some of the super atomic orbitals disappear due to the interaction between monomers. The assembly based on U@B40 induced a decrease in the energy gap. This study provides a basis for a deep understanding of controlling the cluster-assembled materials for tailoring their functionalities.

In this work, a serials of PS(polystyrene)/Cu2S/Ag sandwich substrates were successfully constructed using the magnetic sputtering method by adjusting the Ag sputtering time (0 min, 2 min, 4 min, 6 min, 8 min and 10 min) and used as the surface-enhanced Raman scattering (SERS) substrates. When the Ag sputtering time was 6 min, the strongest SERS signal was observed. The optimized SERS substrate has strong SERS activity on 4-mercaptobenzoic acid (4-MBA), the minimum detection limit was 10(-13) M and the enhancement factor was as high as 4.7 x 10(7). In addition, the SERS signals were highly reproducible with small standard deviation. The SERS enhancement mechanism of the PS/Cu2S/Ag system was attributed to the synergistic effect of the chemical mechanism and the electromagnetic enhancement mechanism. This strategy has find a new way for manufacturing SERS activity sensor with high sensitivity and reproducibility. (C) 2021 Elsevier B.V. All rights reserved.

A PS/Au/ZIF-8 hybrid was successfully prepared and used as a SERS active substrate. Meanwhile, the hybrid SERS substrate exhibited good SERS reproducibility, and we successfully obtained an ultrahigh enhancement factor of 1.67 × 106.

Adjusting the spin polarization of carbon nanotubes is critical for achieving functional applications of spintronic devices such as magnetic switches. Herein, heterojunction carbon nanotubes (HCNTs) are constructed by connecting two different zigzag edges to achieve this goal. First‐principles calculations indicate spin ferromagnetic (FM) or antiferromagnetic (AFM) coupling in the corresponding structure, which can be regulated by the number of carbon atoms at the zigzag edges of the HCNTs. Further calculations related to the charged HCNTs indicate that electronic ground states of the same structure can be transformed from spin AFM to spin FM coupling states. Thus, the behavior of spin polarization for zigzag–zigzag HCNTs can also be regulated by the charge. This finding opens up a new approach for spin adjustment, which can potentially contribute to the design of spintronic devices.

Synopsis Polar, non-polar and cross-shaped isomers of OCS dimer are observed and the corresponding structures are resolved using fs laser-induced Coulomb explosion. These three structures are confirmed in the simulations, and demonstrate that the dimer structures can be reconstructed from the measured momenta distributions. Our study will promote the real time imaging the evolution of molecular dimer at fs time scale after excitation and ionization.

In this work, the monodisperse polystyrene colloidal particles/Ag/zeolite imidazole framework (PS/Ag/ ZIF-8) substrate was successfully prepared and served as SERS active substrate. The composition, structure and morphology of the PS/Ag/ZIF-8 substrates were studied by XRD, SEM, UV-Vis and XPS measurements. The main finding of this study was that the as-prepared PS/Ag/ZIF-8 substrate could exhibit outstanding SERS property when 4-mercaptobenzoic acid (4-MBA) was used as the SERS probes. The SERS mechanism was attributed to the combined effect of the electromagnetic enhancement and chemical enhancement (CT). In addition, the SERS behavior of the sandwich PS/Ag/ZIF-8 substrate exhibit a laser wavelength-dependence CT effect with changing the laser source (473 nm, 514 nm, 633 nm and 785 nm). The wavelength-dependence CT mechanism were discussed briefly in the article. The results showed that the chemical interaction in the structure is a necessary condition for occurrence of the CT. The CT process can be evaluated quantitatively by the charge transfer degree (rho(CT)). Moreover, the enhancement factor (EF) of 1.23 x 10(6) was obtained with 4-MBA probes adsorbed on the synthesized PS/Ag/ZIF-8 substrate. More importantly, our research may open the door for developing the SERS substrate research with the well-studied metal-organic frameworks nanostructures materials. (C) 2020 Elsevier B.V. All rights reserved.

We investigate the sequential double ionization dynamics for the dissociative channel C+ O+ of CO molecules in strong circularly polarized laser fields. By using four-particle coincident measurement, the obtained ionic angular emissions and molecular frame photoelectron angular distributions of each ionization steps for various pathways reveals the significant effects of multiorbital ionization and laser-driven excitation.

We proposed a 1×N-channel cross-grid microring resonator array (MRRA) model according to the coupled mode theory (CMT), electro-optic (EO) modulation theory, and microring resonance theory. This model integrates wavelength division multiplexing and switching functions. When this model is subjected to an operating voltage, the horizontal channel outputs a new resonance wave. As an example, the 1×8-channel cross-grid MRRA with 1550-nm central wavelength and 0.8-nm wavelength spacing is used to analyze its transmission characteristics. The simulation results show that the resonant wavelength in the horizontal channels shifts when the sectional size of the waveguide core, the buffer layer thickness between the waveguide core and electrode, electrode thickness, and coupling gap between the microring and channel are 1.5×1.5μm2, 2.0 μm, 0.05 μm, and 0.1μm, respectively; this shift also occurs when the switching voltage changes from 0 to 21.3V. Thus, resonance wavelength conversion with 0.8-nm wavelength spacing can be achieved in the same horizontal channel.

Herein, a cross-grid microring resonator electro-optic switching array model is proposed on the basis of the coupled mode theory, electro-optic modulation theory, and microring resonance theory. The proposed device has N+1 horizontal channels, N vertical channels, and 2N microrings with equal radii. By applying an operating voltage to the microrings in the array unit in various ways, the switching function of the N+1 horizontal channel can be realized. Taking the structure of 9 × 8 channels as an example, the output spectrum, insertion loss, crosstalk, extinction ratio, and other characteristics of this switching array device under a resonant wavelength of 1550 nm are simulated and analyzed.

A series of heteroleptic cyclometalated Ir (III) complexes with low-color-temperature and low-efficiency roll-off properties, which cause a fast reduction in efficiency when the drive current increases, for organic light-emitting devices are investigated theoretically to explore their electronic structures and spectroscopic properties. The geometries, electronic structures, lowest-lying singlet absorptions and triplet emissions of (ptpy)(2)Ir(acac), and the theoretically designed models (ptpy)(2)Ir(tpip), (F-ptpy)(2)Ir(acac), (F-ptpy)(2)Ir(tpip), (F-2-ptpy)(2)Ir(acac) and (F-2-ptpy)(2)Ir(tpip), are investigated with density functional theory approaches, where ptpy denotes 4-phenylthieno [3,2-c] pyridine, acac denotes acetylacetonate, tpip denotes tetraphenylimido-diphosphinate, F-ptpy denotes 4-(3-fluorophenyl) thieno [3,2-c] pyridine, and F-2-ptpy denotes 4-(2,4-difluorophenyl) thieno [3,2-c] pyridine.