Search Results (636)

Soil salinization critically restricts melon production, and the seed germination stage is particularly vulnerable to saline–alkali stress (SAS). Although silicon (Si) is known to enhance plant stress tolerance, its role in alleviating SAS-induced inhibition of melon seed germination—particularly under combined neutral and alkaline salt stress—remains insufficiently characterized. Here, using the melon cultivar ‘Xinyinhui’, we simulated SAS with a mixture of NaCl and NaHCO₃ and screened for the optimal Si concentration. We then systematically examined physiological, biochemical, and gene expression responses. SAS significantly inhibited germination (20.4% reduction in germination rate; 56.9% in vigor index) and induced oxidative damage (MDA increased by 9.7%; superoxide anion by 170.6%), suppressed antioxidant enzyme activities (SOD −28.8%, POD −69.4%), and disturbed starch metabolism. Exogenous Si at 1.25 mmol·L⁻¹ effectively alleviated these effects: The germination rate increased from 71.7% to 88.8%, and SOD and POD activities increased by 26.7% and 63.6%, while MDA and superoxide anion decreased by 7.1% and 16.4%. Si also promoted starch degradation, as indicated by a 13.9% reduction in starch content, 8.4% increase in total amylase activity, and 23.2% upregulation of CmBMY expression. In addition, Si significantly improved root morphology: Root surface area, volume, branch number, and tip number increased by 19.8–326.3%, while the average root diameter decreased by 24.4%. These results suggest that exogenous Si alleviates SAS inhibition of melon seed germination through coordinated regulation of antioxidant defense and starch metabolism rather than through a single pathway. Our findings provide a physiological basis for the potential application of Si fertilizer in melon cultivation under saline–alkali conditions. Full article

In this research, a signal-integrity control strategy of a through-silicon via (TSV) array for a Chiplet-based system is developed, based on the backpropagation neural network (BP-NN) model and particle swarm optimization algorithm with linear decreasing inertia weight (PSO-LDIW). Based on the HFSS software, the simulation results of the TSV array are obtained. The irregular relationship between design parameters (TSV pitches, height of TSV, radius of TSV, thickness of oxide layer, and offset angle) and signal indexes (return loss, insertion loss, near-end, and far-end crosstalk) is established by the BP-NN model. Then, the design parameters of the TSV array are optimized by the PSO-LDIW algorithm to obtain the desired signal indexes. Based on the optimized design parameters, the effectiveness of the developed signal-integrity control strategy is verified by HFSS simulations. For the three verification cases, the relative errors between the BP-NN-predicted values and the corresponding HFSS simulation values range from 0.31% to 5.02%. The relative deviations of the HFSS results from the desired NEXT, FEXT, and return-loss targets are no greater than 5.72%, while the maximum absolute deviation from the desired insertion-loss target is 0.0160 dB. These results demonstrate the feasibility of the developed strategy for controlling the signal indexes of the TSV array in the tested cases. Full article

We propose a three-dimensional (3D) integrated optical switch that leverages liquid crystal (LC) birefringence to achieve reconfigurable light routing for particular suitability for quantum optical communication. In our design, the large refractive index contrast between an LC’s ordinary (n_o) and extraordinary (n_e) indices is exploited by using n_o as an effective cladding and n_e as the core of voltage-controlled waveguides. This allows dynamic waveguide formation not only in-plane (horizontal routing on chip) but also vertically through stacked polymer layers, realizing a 3D switching architecture beyond traditional planar photonic circuits. A prototype multi-layer structure on a silicon substrate is described, incorporating alternating polymer cladding and core films with embedded LC cells that act as switchable waveguide segments. Simulations confirm that the LC switch can confine and direct light between different layers with low loss, enabling compact 3 × 3 and potentially up to 10 × 10 port-count switching matrices. The device is electrically driven (no moving parts) and can be operated at low voltages, ensuring compatibility with photonic integrated circuit fabrication. The simulated LC response time on ON/OFF is on the order of 1.1 ms/45 ms, which is slower than MEMS or electro-optic switches, but, however, sufficient for quantum key distribution and other quantum network applications where ultrafast switching is not required. Overall, this LC cell-based 3D optical switch offers a promising route toward scalable, low-loss photonic switching nodes for next-generation quantum communication networks. Full article

The integration of advanced semiconductor architectures strictly mandates process thermal budgets below 200 °C, positioning low-temperature PECVD of silicon nitride (SiN_x) film as a critical layer. However, SiN_x film deposited at sub-200 °C inherently exhibits sluggish deposition kinetics and degraded spatial uniformity. To overcome these bottlenecks, this study systematically investigates the regulatory mechanisms of the NH₃ precursor within SiH₄/N₂-based plasmas under varying chamber pressures and substrate temperatures. The results show that the introduction of NH₃ at 2.1 Torr, leveraging its facile plasma dissociation, drastically enhances the deposition rate from 18.2 to 39.1 Å/s and improves thickness uniformity by 1.07%. Meanwhile, NH₃ supplies abundant highly reactive radicals that elevate the refractive index and reinforce compressive stress. Furthermore, film properties exhibit a higher sensitivity to pressure than to temperature, primarily due to the pronounced influence of pressure on plasma dynamics and collision frequencies, whereas the effect of temperature remains comparatively minor. This phenomenon is clearly demonstrated by the Si–H and N–H content. This study validates that operating at low chamber pressures maximizes the collision-free travel distance of SiN_x radicals, providing an optimized and quantified process window for high-volume manufacturing of low-temperature SiN_x film. Full article

A simplified design framework for narrowband terahertz thermal emitters based on a resonant Salisbury-type structure is investigated numerically. The structure consists of a metallic backreflector, a dielectric spacer, and a thin resonant layer with a Lorentz-type dielectric response. Using the transfer matrix method, we show that matching the intrinsic resonance of the resonant layer with an interference resonance of the Salisbury structure enables selective enhancement of a single emissivity peak without requiring time-consuming full-wave optimization at the initial design stage. The influence of spacer thickness, refractive index, and resonance strength on the spectral response is analysed, providing simple guidelines for tuning the emission frequency and suppressing parasitic peaks. A realistic implementation based on a graphene metamaterial layer on a silicon spacer is also investigated using finite-element simulations to demonstrate the applicability of the proposed design concept. The obtained emissivity and thermal emission spectra show that the approach can be used for the efficient design of spectrally selective terahertz thermal emitters in the 10–40 THz range. Full article

Monocrystalline silicon, with its high refractive index, high infrared transmittance, and excellent dimensional stability, serves as a key optical component in high-energy laser systems, infrared imaging, and guidance fields. Its processing quality directly affects the performance indicators of related systems. To address the challenges of nanoscale precision shape and property control during processing, methods such as ultra-precision cutting, magnetorheological polishing, laser micromachining, ion beam processing, plasma etching, and chemical–mechanical polishing have been adopted to improve the surface shape accuracy and repair defects of monocrystalline silicon components. This paper reviews the research progress of key technologies, including nanoscale precision surface shape control manufacturing technology, nanoscale precision property control generation methods, and combined processes for its nanoscale shape and property control, providing technical support for achieving nanoscale precision shape and property control manufacturing of monocrystalline silicon components. Full article

We propose a novel silicon-based THz Mach–Zehnder interferometer (MZI) biosensor integrated with a polarization splitter and rotator (PSR). An optimized PSR is positioned at the input of the MZI, enabling arbitrary polarization inputs to be converted into the same TE mode, which eliminates the dependence of conventional MZI sensors on the input light polarization. The PSR structural parameters are optimized using 3D-FDTD simulations to achieve phase matching, and the calculation results show that efficient TM–TE-polarization conversion occurs along a coupling length of 22.9 mm. Furthermore, the PSR achieves a maximum TE-mode extinction ratio of −30.1 dB and a polarization conversion efficiency of 82.33% in the 0.44 to 0.45 THz range, effectively maintaining the polarization consistency of light entering the MZI. Meanwhile, the characteristic frequency shows a regular blue shift with increasing external refractive index, and the final results demonstrate that the designed MZI biosensor achieves a high sensitivity of 13,215.81 nm/RIU near the center frequency of 0.45 THz. All results presented in this work are obtained through numerical simulations, and experimental validation as well as analyte-concentration-dependent refractive index characterization will be addressed in future studies. To sum up, we propose a high-sensitivity terahertz MZI biosensor featuring a PSR with an on-chip integration scheme, which supports arbitrary polarization inputs and offers a highly integrated solution for specific detection in biomedicine. Full article

High-index silicon surfaces provide anisotropic step networks, reconstruction states, and facet-adjacent geometries that can modify the first stages of III–V heteroepitaxy. This critical review examines GaAs/AlGaAs growth on Si$\left(hhl\right)$ surfaces, with emphasis on the coupled roles of substrate orientation, surface preparation, first-monolayer initiation, and molecular beam epitaxy kinetics. The central viewpoint is that high-index Si can act as an active interfacial template: its anisotropy can bias early nucleation, relaxation, and faceting pathways before any intentional lithographic patterning is introduced. The discussion is anchored in two recent GaAs/Si studies. The first is a matched-condition benchmark comparing Si(001), Si(113), Si(111), and Si(331) under Ga-first and As-first initiation. The second is a Si(331) case study in which Ga pre-exposure followed by low-rate GaAs nucleation yields laterally ordered nanocorrugation/faceting and measurable in-plane optical anisotropy under the explored conditions. Surface-science precedents from adsorbate-induced reconstructions provide additional context for treating the first atomic layer as a meaningful growth variable. These studies point to a broader opportunity: using high-index Si$\left(hhl\right)$ surfaces to link interface chemistry, anisotropic morphology, structural relaxation, and optical response within a common framework for GaAs/Si integration. Full article

Traditional tunable Bragg waveguide grating filters, which rely on thermo-optic or carrier effects, often face limitations such as high energy consumption, low tuning efficiency, and difficulty in achieving independent multi-parameter control. To overcome these bottlenecks, this work proposes a novel optical waveguide filter based on the heterogeneous integration of silicon nitride and the phase-change material Sb₂Se₃. The device leverages the substantial refractive index contrast between crystalline and amorphous states of Sb₂Se₃ to construct a programmable Bragg grating within the thin film layer. This is realized through laser-induced phase transition method, enabling nonvolatile manipulation of the light field. Simulation results indicate that the independent tuning of central wavelength over 19.2 nm range was achieved by adjusting the grating width and ripple width simultaneously. Likewise, the extinction ratio could be independently controlled over 22.3 dB through coordinated adjustments of the grating length and position shift. Beyond its tuning capabilities, the proposed device theoretically exhibits exceptional performance characteristics, including an ultra-low insertion loss of 0.1 dB and strong side lobe suppression. These advantages highlight the potential of this approach to provide a low energy consumption, multifunctional solution for integrated photonic devices, offering a promising pathway for the next generation of programmable photonic integrated circuits. Full article

Decarbonizing heavy-duty logistics requires powertrains that integrate novel topology design, degradation-aware optimization, and robust dynamic performance under real-world operational loads. While solid oxide fuel cells offer high efficiency, their application in transportation is hindered by thermal fatigue. This study proposes a novel hybrid powertrain topology integrating a metal-supported solid oxide fuel cell (SOFC), a micro gas turbine (MGT), and an aluminum–silicon phase change material (PCM) thermal buffer. A high-fidelity dynamic model is developed and coupled with a multi-objective optimization framework to size the PCM buffer and battery pack, balancing capital expenditure and system lifetime. Furthermore, a degradation-aware energy management strategy based on a thermal state-of-charge metric is introduced. Simulations over a 10 h dynamic drive cycle indicate that the optimal configuration (120 kg PCM, 80 kWh battery) extends the SOFC’s simulated remaining useful life to 38,400 h, a 2.5-fold improvement over unbuffered systems. Concurrently, the proposed energy management strategy reduces the MGT mechanical wear index by 98% compared to conventional load-following strategies. The system demonstrates robust performance across ambient temperatures from −20 °C to +45 °C and achieves a 22% reduction in projected capital expenditure compared to standard proton exchange membrane fuel cell powertrains. This topology offers a highly durable and economically viable pathway for next-generation zero-emission heavy-duty vehicles. This work addresses a critical gap in the literature: the lack of integrated thermal buffering and degradation-aware control strategies for high-temperature fuel cell systems in dynamic vehicular applications. By coupling a physical latent heat buffer with a novel Thermal-SOC-proportional Energy Management Strategy, the proposed architecture directly targets the primary degradation mechanisms that have historically impeded SOFC commercialization in heavy-duty transport. Full article

Although coconut water is recognized for its desirable sensory appeal and nutritional composition, its broader industrial use is constrained by the rapid deterioration that occurs after extraction. In this study, crossflow microfiltration of coconut water with a silicon carbide membrane was optimized by investigating pressure and temperature through a face-centered design (FCD) and artificial neural network modeling coupled with a genetic algorithm (ANN–GA). Permeate flux and fouling index were used as process responses, and the optimized condition was further examined in terms of hydraulic resistance, fouling behavior, and retention of minerals and primary metabolites. Pressure and temperature affected the process differently: permeate flux showed marked nonlinear behavior, whereas fouling index was governed mainly by pressure. At the sample level, ANN described permeate flux more accurately than FCD (R² = 0.99 vs. 0.96), whereas FCD showed better grouped cross-validated predictivity across unseen pressure–temperature conditions (Q² = 0.85 vs. 0.57). For the fouling index, FCD outperformed ANN in both sample-level fit and grouped validation (R² = 0.95 vs. 0.60; Q² = 0.70 vs. 0.61). Both approaches converged on the same favorable operating window, and experimental validation at 60 kPa and 35 °C yielded 1085.23 ± 23.12 L h⁻¹ m⁻² and 83.56 ± 1.56%. During concentration mode, flux decline was severe but predominantly reversible, with high clean-water permeance recovery after chemical cleaning. Resistance partition and fouling modeling indicated that the main hydraulic limitation was associated with concentration polarization and external cake-layer buildup rather than irreversible membrane damage. The clarified fraction also preserved high transmission of major minerals and relevant primary metabolites, indicating that the selected condition combined high productivity, manageable fouling, and satisfactory nutritional retention. Full article

The water bodies of southern Kazakhstan are under strong anthropogenic pressure, underscoring the relevance of their comprehensive research. In the summer of 2025, hydrobiological and hydrochemical studies were conducted at 32 stations across seven water bodies in the region. The dissolved solids content (TDS) ranged from 239.5 to 1472.5 mg/dm³, with favorable oxygen levels and relatively low nutrient levels. Zooplankton comprised 100 species, with rotifers predominating. Zooplankton abundance was 133.2–1289.9 thousand specimens/m³, with a biomass of 0.99–3.94 g/m³. The average number of species per sample varied from 11.5 to 26.7. The Shannon index values ranged from 1.20 to 2.74 bits. The average individual mass of a specimen varied from 0.0011 to 0.0371 mg. Cluster analysis revealed significant differences in the species composition of planktonic invertebrates across water bodies and their biotopes, which, according to the MDS analysis, reflected heterogeneity in external conditions. Analysis of multivariate data showed that the main factors shaping summer zooplankton community structure in the surveyed water bodies were TDS, silicon, and phosphate. The reasons for the identified dependencies between abiotic and biological variables are discussed. The high indicator significance of zooplankton communities in assessing the ecological state of aquatic ecosystems is demonstrated. Full article

Integrating semi-transparent photovoltaics (STPV) into greenhouse structures offers an effective approach to optimizing the Food–Energy Nexus and maximizing sustainable land-use efficiency. However, a knowledge gap remains regarding how specific STPV spectral signatures drive plant morpho-physiological acclimation across multiple cultivation cycles. This study presents a 19-month multi-cycle, proof-of-concept evaluation of the structural growth dynamics and physiological responses of generative (tomato) and vegetative (lettuce) crops under greenhouse prototypes with two distinct thin-film STPV technologies: Cadmium Telluride (CdTe) and amorphous Silicon (a-Si), compared to an unshaded transparent control. Biometric monitoring revealed that morphological acclimation (Shade-Avoidance Syndrome) was highly plastic, driven by the interplay between spectral filtering and seasonal irradiance limits. While structural adaptations, such as foliar expansion and stem elongation under the a-Si spectrum, were pronounced during specific transitional seasons (e.g., early spring), these morphological differences largely homogenized across treatments during periods of extreme high or low natural irradiance. Despite the shading penalty, this morphological acclimation successfully sustained agronomic fresh mass. Systemic efficiency, quantified by the Land Equivalent Ratio (LER) as a relative biophysical synergy index, demonstrated notably crop-specific synergies. Under an extended single fruiting cycle, the CdTe prototype showed potential to improve yield, achieving a maximum LER of 1.66 for the high-light-demanding tomato (Y_crop = 1.40). Conversely, the a-Si module excelled with the shade-tolerant lettuce during early vegetative stages in high-radiation periods, achieving peak LERs up to 1.55. These findings provide a biophysical baseline to help guide future scalability assessments prior to full-scale commercial agrivoltaic (APV) implementation for sustainable food systems. Full article

Color results from the interaction of objects with varying wavelengths of light and the human visual system’s perception under different illumination conditions. In this study, special emphasis was placed on examining how varying illumination conditions and measurement geometries affect the color appearance and optical properties of printed effect pigments. Two distinct groups of pigments were examined: three interference pigments (M-series) based on calcium–aluminum borosilicate substrates, and three multicolor pigments (C-series) based on silicon dioxide. To ensure comparability of the results, all pigments were printed using screen printing techniques onto black PVC film. Characterization involved using a multi-angle spectrophotometer to measure CIEL*a*b* values, chroma (C*), and hue (h*) under CIE standard illuminants D50, A2, and F2 at a fixed illumination angle of 45° and aspecular angles of −15°, 15°, 25°, 45°, 75°, and 110°. Furthermore, the research methodology included the evaluation of lightness difference (∆L*), color differences (∆E*), chroma difference (∆C*), and hue difference (∆H*), with the D50 illuminant chosen as the reference and A2 and F2 as sample illuminants. The flop index (FI), as the indicator of lightness change at different scattering angles, was calculated for all printed pigments under all three standard illuminations. This multidisciplinary approach provided a deeper understanding of the relationship between pigment structure, illumination conditions, and viewing angles in our visual perception of printed pigments, which is of great importance for the development and optimization of goniochromatic materials. The results showed that while A2 and F2 illuminants have a negligible impact on lightness differences across all pigments, they induce noticeable variations in color, chroma, and hue differences, particularly at near-specular angles (−15° and 15°). Conversely, these differences become negligible at far-aspecular angles (75° and 110°). Furthermore, flop index (FI) analysis revealed that despite the larger borosilicate flakes in the M-series, the silicon dioxide-based C-series pigments exhibited the highest overall flop effect, with pigment C1 maintaining consistently high FI values under all illuminants. Full article

Graphene–plasmonic electro–optic (EO) modulators have attracted significant interest for compact and energy-efficient integrated photonic systems due to their electrically tunable optical response and strong light–matter interaction. In this work, an ultra-thin silicon-on-insulator (SOI) graphene–plasmonic slot modulator (G-PSM) is investigated using a combined semi-analytical and numerical framework. The analysis integrates finite-temperature Kubo conductivity modeling, perturbation-based effective-index analysis, overlap-factor evaluation, eigenmode analysis, and full-wave simulations to study the influence of silicon thickness on the EO performance of the proposed structure. The obtained results demonstrate that geometry engineering strongly affects modal confinement, overlap enhancement, effective-index perturbation, transmission characteristics, extinction ratio (ER), insertion loss (IL), energy-per-bit consumption, and EO bandwidth. Under optimized operating conditions, the proposed G-PSM achieves an effective refractive-index variation of approximately $3.1\times {10}^{-3}$, an ER of approximately 3.5 dB, an IL of 1.5–2 dB, an energy-per-bit consumption of approximately 7.5 fJ/bit, and a 3 dB EO bandwidth approaching 200 GHz. Strong electromagnetic confinement is achieved inside the plasmonic slot region near the graphene-active layer, enabling efficient electro–absorptive and electro–refractive modulation. Excellent agreement between the semi-analytical calculations and numerical simulations validates the developed framework and confirms the suitability of the proposed ultra-thin SOI G-PSM for compact broadband EO modulation in future integrated photonic systems. Full article