This paper presents a low-cost, high-gain 1 × 4 collinear slot phased array for 5G millimeter-wave (mmWave) applications, which is realized on a two-layer standard printed circuit board. The design specifically addresses two key challenges in mmWave phased array design, which are mitigating the strong mutual coupling that limits wide-angle scanning performance and enabling the low cross-polarization radiation structure. A key innovation is the use of a periodically bent ridge within a ridge substrate integrated waveguide to efficiently excite a centerline collinear slot configuration, which minimizes cross-polarization. Furthermore, a compact via-based choke structure is introduced to suppress mutual coupling and thus achieve high inter-element isolation. The fabricated prototype exhibits an impedance bandwidth of 10.7% (26.5–29.5 GHz). The measured results show a peak gain of 14.5 dBi, port isolation better than 19 dB, and a stable 3-dB scanning range of ±50°. These results validate the proposed design as a compelling low-cost solution that achieves an excellent balance of high gain, wide-angle scanning, and high isolation.

This study investigates a novel class of flexible plate metamaterials (FPMMs), consisting of a periodic array of bottom-mounted flexible structures, designed for the sub-wavelength manipulation of surface gravity waves. A theoretical framework is developed by coupling the matched eigenfunction expansion method with a modal expansion technique, incorporating Bloch’s theorem to characterise the band structures and complex dispersion relations. Numerical analysis reveals that the structural flexibility facilitates the formation of low-frequency, broadband bandgaps, primarily driven by a local resonance (LR) mechanism. It is shown that wave propagation can be effectively suppressed within these bandgap regimes through the synergistic interaction between the incident wave field and the structural vibration modes. The theoretical predictions are validated through laboratory experiments conducted in a wave flume, where substantial wave attenuation was observed under resonant conditions. Notably, the LR-induced bandgaps occur at significantly lower frequencies and exhibit broader bandwidths compared to those arising from traditional Bragg resonance. These findings demonstrate that the proposed FPMMs provide a tunable and effective mechanism for sub-wavelength wave attenuation, offering fundamental insights into localised hydrodynamic wave control.

The flow behaviour of an inclined jet in crossflow (JICF) subjected to different upstream roughness regimes – smooth, transitionally rough (${k}_{s}/{D}=0.129$, where $k_{s}$ is the equivalent roughness height and $D$ is the jet hole diameter) and fully rough (${k}_{s}/{D}=0.782$) – is investigated using refractive-index-matching time-resolved particle image velocimetry for velocity ratios VR = 0.33, 0.67 and 1.0. The transitionally rough regime produces intensified, unbroken large-scale vortices that induce strong intermittency in the boundary-layer thickness. Its energy spectrum retains the original multi-scale coherence, but exhibits an additional wavelength associated with this intermittency. This intermittent state imposes the strongest unsteady influence on the downstream JICF, manifested as a binary flow pattern consisting of alternating jet lift-off and regular shedding. Time-averaged fields show a vertically elongated counter-rotating vortex pair (CRVP), while extended spectral proper orthogonal decomposition (ESPOD) indicates that the binary state drives modal bifurcation and distinct pathways associated with prematurely initiated centreline disturbance amplification. In contrast, the fully rough regime promotes rapid breakdown into small-scale turbulence. The ESPOD confirms that multi-scale frequency coherence decays rapidly, whereas low-frequency coherence experiences a brief amplification due to upstream signal injection. Additionally, secondary flows are observed to exert a localised, asymmetric modulation of the CRVP at VR ≤ 0.67: on the high-momentum pathway (downwash) side, one CRVP lobe is vertically compressed and its decay is delayed, while on the low-momentum pathway (upwash) side, the opposite lobe is vertically stretched and its decay is accelerated.

This work presents an integrated modelling study of fast-proton distributions generated by ion cyclotron range of frequency (ICRF) minority heating in the Experimental Advanced Superconducting Tokamak (EAST). Using a series of high-confinement (H-mode) discharges with increasing ICRF power levels from 0.8 to 2.4 MW, fast protons were produced via minority heating mechanisms and analysed through simulations using the ASCOT code. The results reveal that the fast protons are primarily concentrated near the fundamental cyclotron resonance layer and exhibit strong power-dependent behaviour in both real-space (R–Z) distribution and velocity space, where R is the major radius and Z is the vertical coordinate. As the ICRF power increases, the energetic proton population shows significant spatial broadening and energy enhancement, reaching up to 1 MeV. The fast-ion pitch-angle distribution becomes increasingly anisotropic, with high-energy ions concentrated around $|\textit{v}_{\|}/\textit{v}| \lt 0.5$, where $\nu$ is the magnitude (speed) of the full velocity vector of the particle. Furthermore, the energy density of fast ions aligns well with the ICRF power deposition profile, confirming efficient central-core heating. These findings, which provide insight into fast-ion behaviour and ICRF heating characteristics in EAST plasmas, also support future fast-ion diagnostics and performance control strategies in EAST and similar experimental conditions.

The citrus industry is vital to regional economies, and scientific land suitability evaluation is essential for spatial optimisation. This study focuses on Tongcheng County in Hubei Province, which exemplifies a typical red soil hilly region that is ecologically vulnerable in southeastern China. This study integrates Geographic Information System (GIS), Analytic Hierarchy Process (AHP), and fuzzy mathematics to develop a comprehensive land suitability evaluation model that balances factor continuity with evaluation uncertainty. Multi-source spatial data (climate, topography, soil) were used to quantify fuzzy membership functions for citrus growth. Subsequently, we conducted a weighted overlay analysis based on this quantification, which resulted in the creation of a citrus cultivation suitability evaluation map for Tongcheng County. The evaluation results categorised the study area into three distinct zones: (1) The Optimal Zone (CAI ≥ 0.75), which comprises 75.8% (857 km2) of the total study area; (2) The Suitable Zone (0.55 ≤ CAI ≤ 0.75), which constitutes 19.6% (222 km2) of the total study area; and (3) The Unsuitable Zone (CAI ≤ 0.55), which represents 4.6% (52 km2) of the total study area. The research findings aligned with the actual conditions in Tongcheng County, thereby confirming the feasibility of the employed research methodology. These outcomes address research gaps and provide a replicable methodological framework for land evaluation in mountainous regions. This approach can be directly utilised in local agricultural spatial planning and the development of land-use policies. It carries substantial practical implications for advancing sustainable agricultural development and revitalising rural areas in mountainous regions.

Using different techniques to derive dietary patterns (DP) could evaluate real-world diet behaviours and provide DP recommendations. Therefore, we identified DP using hybrid methodologies and examined the associations of DP with all-cause and CVD mortality among older Chinese. Using data from the Guangzhou Biobank Cohort Study, dietary intake was assessed using a validated FFQ. DP were derived using hybrid methods including reduced rank regression (RRR) and partial least squares (PLS), focusing on nutrients commonly insufficient in Asian diets. Associations of the DP with mortality and CVD risk factors were examined using Cox regression and generalised linear models, respectively. Of 19 598 participants with an average follow-up of 15·8 years, 4966 deaths occurred. Two DP were derived based on the riboflavin-density, K:Na ratio and vitamin C-density. The DP derived from both RRR and PLS featured high intakes of green vegetables, yellow/orange fruits and whole grains and low intakes of refined grains and plant oils, with additional high intakes of fish identified by RRR and milk by PLS. These DP were associated with lower all-cause and CVD mortality risks. Compared with the lowest quartile, the highest quartiles showed lower risks of all-cause (hazard ratio (HR): 0·89–0·91, all P < 0·01) and CVD mortality (HR: 0·79–0·82, all P < 0·01). Moreover, both DP were associated with favourable cardiometabolic profiles, including lower systolic blood pressure, TAG and high-sensitivity C-reactive protein levels, and higher HDL-cholesterol levels. These findings suggest that nutrient-rich DP using hybrid methods may support the development of dietary recommendations to reduce mortality among older Chinese.

We investigate the EM approximation for $\mathbb{R}^d$-valued ergodic stochastic differential equations (SDEs) driven by rotationally invariant $\alpha$-stable processes ($\alpha\in(1,2)$) with Markovian switching. The coefficient g violates the dissipative condition for certain states of the switching process. Using the Lindeberg principle, we establish quantitative error bounds between the original process $(X_t,R_t)_{t\geqslant 0}$ and its Euler–Maruyama (EM) scheme under a specially designed metric. Furthermore, we derive both a central limit theorem and a moderate derivation principle for the empirical measures of both the SDE and its EM scheme. The theoretical results are subsequently validated through a concrete example.

The diversity and stability of the gut microbiota, along with various microbial and host–microbe interactions, are crucial factors in maintaining a healthy state. In this study, a total of 12 healthy 1–2 years old cats of similar weight were recruited and divided into two groups according to the experimental design and breed: the British shorthair (BS) group and the nulla luctus felis (NLF) group. After 21 days of the same diet, we analyzed and compared the gut microbiota of BS and NLF. Our results showed that the values of the serum biochemical indicators of the BS and NLF selected for this experiment were within the normal range. The Venn diagram showed that the two groups had 310 common operational taxonomic units. Significant differences in beta diversity (P < 0.05), but not in alpha diversity (P > 0.05), distinguished the two groups. Comparative analysis revealed the NLF group was enriched in Lactobacillus and Bacillus, but depleted in Enterococcus at the genus level (P < 0.05). Furthermore, 59 taxa were established as biomarkers based on a linear discriminant analysis score greater than 3.5. According to PICRUSt2 function analyses, the BS group and NLF group had a ratio of 77.11% and 76.55% for metabolism at level 1, respectively. At level 3, the NLF group significantly increased 15 metabolism pathways, while decreasing 13 metabolism pathways (P < 0.05). Finally, NLF-P1, which was screened from the feces of NLF, exhibited a good antibacterial effect on three strains of pet-associated pathogens, and the evolutionary tree was constructed to show that it may be Lactobacillus paracasei or Lactobacillus casei. In conclusion, there were significant differences in intestinal microbiota composition between BS and NLF, and NLF-P1 has research and application potential.

In this paper, a millimeter-wave (mmWave) wideband high-gain low-temperature co-fired ceramic (LTCC) phased array using ridged substrate integrated waveguide (RSIW) element is proposed, which can cover n257/n258 bands (24.25–29.5 GHz). First, a novel widebeam and high-gain RSIW slot antenna subarray is designed, which is constructed by staggered longitudinal slot that incorporated with additional radiating elements on the non-scanning plane. Further, the proposed widebeam antenna subarray is applied to construct a 1 × 4 array integrated in an LTCC package with small element spacing of about 0.41λ0. Moreover, by adding isolation slots and metal vias between adjacent array elements, the isolation of ports thereby is reduced below −15 dB, and the scanning range is increased up to ±7°. A wideband and low-loss feeding network is realized by series-parallel combined feeding, further improving isolation and scanning performance after assembly. The simulation and measurement demonstrate that the antenna array possesses satisfied beam-scanning capabilities over wide bandwidth of ∼20%, achieving maximum scanning angle up to ±62° while maintaining desirable gain above 14.5 dBi. Furthermore, within the entire operating bandwidth, the scanning angles extend to ±55° with minimal variation. These features show that the proposed antenna array is promising for 5G mmWave communications.

Direct numerical simulations are performed to explore the impact of surface roughness on inter-scale energy transfer and interaction in a turbulent open-channel flow over differently arranged rough walls. With friction Reynolds number approximately 540, six distinct configurations of roughness arrangements are examined. The results show that the clustered roughness arrangements yield notable changes in large-scale secondary-flow structures, which manifest in the profiles of dispersive stresses, predominantly near the roughness elements. They are marked by the presence of spanwise alternating high-momentum pathways and low-momentum pathways. From the outer peak in the spanwise energy spectra, the size and intensity of turbulent secondary flows are shown to be related to the spanwise spacing of the roughness heterogeneity. The emergence of turbulent secondary flows serves to suppress the original large-scale structures in the outer region of smooth-wall turbulence, paving the way for the development of new turbulent structures at the second harmonic scale. Furthermore, the spanwise triadic interaction analysis reveals the mutual energy exchange between the secondary harmonic scale and the secondary-flow scale. These findings elucidate the underlying mechanisms behind the attenuation of large-scale structures in the outer region influenced by roughness, offering new insights into the dynamic interplay of scale interactions in rough-wall turbulence.

Carbon storage in saline aquifers is a prominent geological method for reducing CO2 emissions. However, salt precipitation within these aquifers can significantly impede CO2 injection efficiency. This study examines the mechanisms of salt precipitation during CO2 injection into fractured matrices using pore-scale numerical simulations informed by microfluidic experiments. The analysis of varying initial salt concentrations and injection rates revealed three distinct precipitation patterns, namely displacement, breakthrough and sealing, which were systematically mapped onto regime diagrams. These patterns arise from the interplay between dewetting and precipitation rates. An increase in reservoir porosity caused a shift in the precipitation pattern from sealing to displacement. By incorporating pore structure geometry parameters, the regime diagrams were adapted to account for varying reservoir porosities. In hydrophobic reservoirs, the precipitation pattern tended to favour displacement, as salt accumulation occurred more in larger pores than in pore throats, thereby reducing the risk of clogging. The numerical results demonstrated that increasing the gas injection rate or reducing the initial salt concentration significantly enhanced CO2 injection performance. Furthermore, identifying reservoirs with high hydrophobicity or large porosity is essential for optimising CO2 injection processes.

Hand, foot, and mouth disease (HFMD) shows spatiotemporal heterogeneity in China. A spatiotemporal filtering model was constructed and applied to HFMD data to explore the underlying spatiotemporal structure of the disease and determine the impact of different spatiotemporal weight matrices on the results. HFMD cases and covariate data in East China were collected between 2009 and 2015. The different spatiotemporal weight matrices formed by Rook, K-nearest neighbour (KNN; K = 1), distance, and second-order spatial weight matrices (SO-SWM) with first-order temporal weight matrices in contemporaneous and lagged forms were decomposed, and spatiotemporal filtering model was constructed by selecting eigenvectors according to MC and the AIC. We used MI, standard deviation of the regression coefficients, and five indices (AIC, BIC, DIC, R2, and MSE) to compare the spatiotemporal filtering model with a Bayesian spatiotemporal model. The eigenvectors effectively removed spatial correlation in the model residuals (Moran’s I < 0.2, p > 0.05). The Bayesian spatiotemporal model’s Rook weight matrix outperformed others. The spatiotemporal filtering model with SO-SWM was superior, as shown by lower AIC (92,029.60), BIC (92,681.20), and MSE (418,022.7) values, and higher R2 (0.56) value. All spatiotemporal contemporaneous structures outperformed the lagged structures. Additionally, eigenvector maps from the Rook and SO-SWM closely resembled incidence patterns of HFMD.

Let $(X_t)_{t \geqslant 0}$ be the solution of the stochastic differential equation

\[\mathrm{d} X_t = b(X_t) \,\mathrm{d} t+A\,\mathrm{d} Z_t, \quad X_{0}=x,\]

$b\,:\, \mathbb{R}^d \rightarrow \mathbb{R}^d$

$A \in \mathbb{R}^{d \times d}$

$(Z_t)_{t\geqslant 0}$

$\alpha$

$\alpha \in (1,2)$

$x\in\mathbb{R}^{d}$

$\Gamma = (\gamma_n)_{n\in \mathbb{N}}$

$(X_t)_{t \geqslant 0}$

$\alpha$

$\gamma^{\frac{1}{\alpha}}_n$

$\gamma^{1+\frac {1}{\alpha}-\frac{1}{\kappa}}_n$

$\kappa \in [1,\alpha)$

$\gamma^{\frac{2-\alpha}{\alpha}}_n$

$\alpha$

In this paper, we investigate the number of customers that overlap or coincide with a virtual customer in an Erlang-A queue. Our analysis starts with the fluid and diffusion limit differential equations to obtain the mean and variance of the queue length. We then develop precise approximations for waiting times using fluid limits and the polygamma function. Building on this, we introduce a novel approximation scheme to calculate the mean and variance of the number of overlapping customers. This method facilitates the assessment of transient overlap risks in complex service systems, offering a useful tool for service providers to mitigate significant overlaps during pandemic seasons.

In this paper, on–off switching digitization of a W-band variable gain power amplifier (VGPA) with above 60 dB dynamic range is introduced for large-scale phased array. Digitization techniques of on–off switching modified stacking transistors with partition are proposed to optimize configuration of control sub-cells. By the proposed techniques, gain control of a radio frequency variable gain amplifier (VGA) could be highly customized for both coarse and fine switching requirements instead of using additional digital-to-analog converters to tune the overall amplifier bias. The designed VGA in 130 nm SiGe has achieved switchable gain range from −46.4 to 20.6 dB and power range from −25.0 to 15.7 dBm at W band. The chip size of the fabricated VGPA is about 0.31 mm × 0.1 mm.

We document firms often determine CEO equity grants based on a predetermined dollar value (value-based equity grant) instead of on the number of shares (share-based grant). Value-based equity grants weaken the relationship between stock performance and CEO equity pay, lower CEO portfolio delta, and slow firms’ investment in R&D. We find that retention pressure is a key reason for the use of value-based equity pay, while governance could also matter. Overall, this paper alerts boards to the unintended consequences of pursuing a target pay level or pay structure because such practices can lead to value-based equity grants in CEO compensation.