Northwestern Polytechnical University

The multi-stage manufacturing system (MMS) is a form of production process organization in modern industry, which refers to a kind of manufacturing system that organizes a variety of production steps, processes, or stages in a certain order to complete the processing of final products. With the increasing requirement for effective management of quality and reliability in manufacturing systems, the research on modeling, evaluating, and optimizing multi-stage manufacturing systems is brought into sharp focus. As one kind of complex system, a multi-stage manufacturing system has a wide range of unit types, performance indexes, and optimization methods, which breed a variety of study paradigms to accommodate different management decisions of MMS. In view of operation risk management, this paper reviews the studies about the unit-reliability model, system performance evaluation, and system performance optimization. In detail, the models covering the main information and physical units of MMS are studied. At the system level, different performance indexes for operation risk evaluation are reviewed, and general optimization activities and methods are also reviewed, such as the optimization for maintenance plan, inspection activities, rework operation, and their joint optimizations. Through these contents, the purpose of this study is to offer a quick review of the study paradigm of MMS, promoting the research and application of complex MMS.

Recent progress has demonstrated that synthetic gauge fields can mimic Landau quantization in materials including graphene and lattices for sound and light. However, despite using graphene-like structures with strain-induced textures in prior photonics, it is hard to capture the experimental attainment of distinct photon bound states for various Landau levels. In this work, we introduce an experimental framework for achieving photonic Landau quantization. We present the quantized distribution of photonic states across different Landau levels in a two-dimensional Kagome metal lattice. By introducing inhomogeneous coupling, we implement two kinds of pseudomagnetic field, which quantize spectrums and quantizes distribution of photonic states, respectively. We experimentally observe that the electric field distribution is localized according to the positional attributes of different Landau levels. Our proposed system is more straightforward to implement, and it opens an avenue to explore photonic states at non-zero Landau levels, which are predicted to demonstrate some interesting physical phenomena.

Defective heterovalent selenides provide a spacious arena for creating emergent electromagnetic (EM) phenomena that are unattainable in the conventional constituent counterparts. However, there are still synthetic methodological challenges, and in‐depth understanding of the EM properties, particularly correlation between tailored polarization sites and dielectric polarization response, are significantly inadequate. Herein, a selective ions exchange strategy driven by concentration‐regulated (Case 1) and time‐evoked (Case 2) approaches, is innovatively proposed to design series of defective heterovalent copper‐based selenides. The controllable phase evolution tailored by concentration‐regulated mixed cation/anion exchange is responsible for heterointerfaces levels (Case 1), while Cu⁺/Cu²⁺ electronic configurations controlled by time‐evoked cation exchange accounted for further manipulating heterointerfaces/defects levels and enriching polarization sites (Case 2). The coupling of nonstoichiometric Cu2−xSe‐containing heterointerfaces, unsaturated Se vacancies and multi‐valence configurations, rather than themselves alone even at a higher level, imparted abundant polarization sites to trigger boosted polarization response for defective heterovalent selenides. Consequently, this designed defective heterovalent selenide (ZnSe/CuSe/Cu2‐xSe) deliveres a broad bandwidth of 6.89 GHz compare to parent ZnSe without dielectric response, outperforming most reported metal selenides until now. This innovative strategy overcame the bottlenecks of conventional synthetic methodology, providing a paradigm for fabricating sophisticated defective heterovalent materials for versatile applications beyond EM absorption.

Acoustic streaming generated by surface acoustic waves (SAWs) enables diverse acoustofluidic functions, such as fluid mixing, particle manipulation, and enhanced fluid transport, making SAWs valuable lab‐on‐a‐chip systems. However, conventional SAW devices are often limited to a specific acoustofluidic function once fabricated. Each function typically requires different devices or designs to produce other wave modes, making exploration costly and time‐consuming. A Multidirectional Interdigital Transducer (M‐IDT) on a Flexible Printed Circuit Board (FPCB) is presented, allowing easy reconfigurability and multidirectional SAW propagation. This versatile device enables rapid, multifunctional experimentation on a single replaceable substrate, facilitating efficient exploration of acoustofluidic effects. This device, alongside finite element simulations, investigates substrate in‐plane rotation angles (0°, 30°, 60°, and 90° relative to the X‐axis) and wave modes. Favorable acoustic velocities are observed using Rayleigh SAW (R‐SAW) at 0° and 30°, and using combined wave modes at 60°, and 90°. The pseudo shear‐horizontal SAW (P‐SH‐SAW) at 90° exhibits higher velocities than R‐ SAW at 0°. P‐SH‐SAW also improved acoustic streaming at lower power, with high‐viscosity fluids, substantial fluid volumes (1 mL), and within a 96‐well plate. The M‐IDTs reconfigurable nature allows rapid, cost‐effective testing, making it ideal for prototyping a wide range of acoustofluidic applications.

This study applies advanced AI techniques, including machine learning algorithms, to explore the numerically unsteady laminar flow of viscous and incompressible fluids in coaxially swirled porous disks, with applications in engineering sciences. Our focus encompasses the effects of magnetic hybrid nanomaterials and the dynamic behaviors associated with expanding/contracting and injection/suction. Utilizing single‐phase simulations, we address nonlinear coupled ordinary differential equations set against appropriate boundary conditions. Key parameters of our study include permeability and relaxation, as well as the influence of chemical reactions and mixed convection on fluid behaviors. The thermophysical properties of Al 2 O 3 /Cu nanoparticles have been by varying their morphological aspects. For the hybrid nanofluids flow, the aggregation of nanoparticle volume fraction has been designed critically in conjunction with an energy and mass transfer equation. Because dimensionless ordinary differential equations are employed, the obtained expression is transmuted using the obliging transformation technique. The desired nonlinear system of ODEs is implemented using an accurate numerical method. Our findings reveal significant impacts of chemical reaction parameters on the Sherwood number and a marked increase in the skin friction coefficient, Nusselt number, and Sherwood number as nanoparticle volume fraction rises from 2% to 7%.

Mitochondrial morphology and function are intrinsically linked, indicating the opportunity to predict functions by analyzing morphological features in live-cell imaging. Herein, we introduce MoDL, a deep learning algorithm for mitochondrial image segmentation and function prediction. Trained on a dataset of 20,000 manually labeled mitochondria from super-resolution (SR) images, MoDL achieves superior segmentation accuracy, enabling comprehensive morphological analysis. Furthermore, MoDL predicts mitochondrial functions by employing an ensemble learning strategy, powered by an extended training dataset of over 100,000 SR images, each annotated with functional data from biochemical assays. By leveraging this large dataset alongside data fine-tuning and retraining, MoDL demonstrates the ability to precisely predict functions of heterogeneous mitochondria from unseen cell types through small sample size training. Our results highlight the MoDL’s potential to significantly impact mitochondrial research and drug discovery, illustrating its utility in exploring the complex relationship between mitochondrial form and function within a wide range of biological contexts.

The development of 3D cell culturing toward labor saving and versatility is highly desired. Here, we propose a platform consisting of a multiwell plate and liquid marbles (LMs). The inner walls of the plate are covered with particle‐detachable superhydrophobic coatings that serve as both the substrates and particle sources for LM production. A produced LM, which serves as a minireactor for the 3D culture, features a monolayer nanoparticulate shell and naked‐droplet‐like transparency. The LM‐in‐plate platform provides a double‐superhydrophobic environment that increases the stability of the 3D culture and reduces the necessary operational cautions. In addition, both cell observation and high‐throughput applications can be conducted in situ, owing to the high LM transparency and the multiwell structure, respectively. This platform integrates the advantages of naked droplets (transparent and clean), LMs (stable non‐wetting), and multiwell plates (high‐throughput capability) and thus is promising for labor‐saving and versatile 3D culturing.

A molecular ligand separation method based on multivariate metal-organic frameworks (MOF) is developed to precisely regulate CuSn alloy for tuning the selectivity of HCOOH and CO in CO2 reduction. With...

Electrocatalytic urea synthesis from carbon dioxide (CO2) and nitrate (NO3⁻) offers a promising alternative to traditional industrial methods. However, current catalysts face limitations in the supplies of CO* and Nrelated* intermediates, and their coupling, resulting in unsatisfactory urea production efficiency and energy consumption. To overcome these challenges, we carried out tandem electrosynthesis approach using ruthenium dioxide‐supported palladium‐gold alloys (Pd2Au1/RuO2). This catalyst system effectively catalyzes CO2‐to‐CO* conversion on Pd2Au1 and NO3⁻‐to‐NH2* conversion on RuO2. Crucially, the minimized work function difference between two components promotes remote CO* spillover from Pd2Au1 to RuO2, improving effective coupling of CO* and NH2* for urea production. Our catalyst demonstrated exceptional performance, achieving a record‐high Faradaic efficiency for urea (FEurea) of 75.6±0.5 % and a urea production rate (rurea) of 73.5±0.8 mmol gcat⁻¹ h⁻¹. Notably, this was accomplished with an ultralow energy consumption of 18.9 kWh kgurea⁻¹. We also successfully demonstrate the long‐term stability of our catalyst in a flow cell, achieving over 160 h of uninterrupted urea and formate production with consistent profitability. This achievement represents a significant step towards the large‐scale practical application of sustainable urea electrosynthesis.

Multicomponent Ti‐containing ultra‐high temperature ceramics (UHTCs) have emerged as more promising ablation‐resistant materials than typical UHTCs for applications above 2000 °C. However, the underlying mechanism of Ti improving the ablation performance is still obscure. Here, (Hf,Zr,Ti)B2 coatings are fabricated by supersonic atmospheric plasma spraying, and the effects of Ti content on the ablation performance under an oxyacetylene flame are investigated. The (Hf0.45Zr0.45Ti0.10)B2 coating shows superior ablation resistance and cycling reliability at ≈2200°C. A functionally graded oxide scale comprising an outer dense layer and an underlying fine granular layer formed. The former is a better oxygen barrier owing to fewer cracks and the latter has high strain tolerance due to finer grain size. The uniform dissolving of ≈4 mol% Ti in the inner layer results in grain refinement via sluggish diffusion and thus stress release. For the outer layer, Ti segregation at the nanoscale leads to a metastable cubic (Hf,Zr,Ti)O2 and local severe lattice distortion, inhibiting the propagation of cracks. Ti ions’ unique dissolving in the oxide scale enables a strong oxygen diffusion barrier with high strain tolerance, which is responsible for superior performance. This study provides new insights into the ablation behavior of Ti‐containing multicomponent UHTCs.

Separation of multi-component mixtures in an energy-efficient manner has important practical impact in chemical industry but is highly challenging. Especially, targeted simultaneous removal of multiple impurities to purify the desired product in one-step separation process is an extremely difficult task. We introduced a pore integration strategy of modularizing ordered pore structures with specific functions for on-demand assembly to deal with complex multi-component separation systems, which are unattainable by each individual pore. As a proof of concept, two ultramicroporous nanocrystals (one for C2H2-selective and the other for CO2-selective) as the shell pores were respectively grown on a C2H6-selective ordered porous material as the core pore. Both of the respective pore-integrated materials show excellent one-step ethylene production performance in dynamic breakthrough separation experiments of C2H2/C2H4/C2H6 and CO2/C2H4/C2H6 gas mixture, and even better than that from traditional tandem-packing processes originated from the optimized mass/heat transfer. Thermodynamic and dynamic simulation results explained that the pre-designed pore modules can perform specific target functions independently in the pore-integrated materials.

A cavitation flow can greatly impact a vehicle's attitude and stability when exiting water. This paper adopts an improved delayed detached eddy turbulence model and a Schnerr–Sauer cavitation model as well as the volume-of-fluid method and an overlapping grid technique to investigate this effect. In addition, the experimental system of the underwater launch is designed and built independently, which the numerical results are in good agreement with the experimental results. The transient cavitation flow structure and motion characteristics of the projectiles successively launched underwater are studied. When the axial spacing ranges from 0 to 1.0 times the diameter of the projectile, both projectiles are severely affected to various extents in cavitation pattern, vortex structure, and motion characteristics. It is worth noting that the internal cavity of the secondary projectile is disturbed by the wake of the primary projectile, resulting in large-scale fractures and detachment of the internal cavity, but its motion stability is good.

The effects of air inlet temperature on the flame structures and the local extinctions of n-decane swirl spray flames at constant air flow velocity were clarified by using the simultaneous planar laser induced fluorescence measurements of OH and CH2O. Results show that the blowoff limit decreases 48% as the temperature increases from 298 to 473 K. The OH and the [CH2O] × [OH] overlap are mainly distributed near the shear layer, while a small amount of formaldehyde is also observed in the outer recirculation zone (ORZ), corresponding to the low-temperature reactions. The formaldehyde intensity in the ORZ varies non-monotonically with the temperature. The non-monotonic temperature dependence of the formaldehyde intensity is governed by the competition of the droplet evaporation rate and the initial droplet size. The local extinctions of swirl spray flames can be identified by the formation of holes or breaks in the OH branches together with the accumulation of formaldehyde. It suggests that the combination of OH and CH2O is a good indicator to predict the local extinctions. The probability of the local extinctions decreases gradually with the temperature. The locations of the local extinction move downstream from 333 to 423 K; however, the local extinctions occur frequently near the flame root at 473 K. It reveals that the local extinctions near the flame root are mainly associated with the cooling effect and the perturbation effect of the flame–droplet interactions at low temperature and at high temperature, respectively.

We propose a universal method based on deep reinforcement learning (specifically, soft actor–critic) to control the chimera state in the coupled oscillators. The policy for control is learned by maximizing the expectation of the cumulative reward in the reinforcement learning framework. With the aid of the local order parameter, we design a class of reward functions for controlling the chimera state, specifically confining the spatial position of coherent and incoherent domains to any desired lateral position of oscillators. The proposed method is model-free, in contrast to the control schemes that require complete knowledge of the system equations. We test the method on the locally coupled Kuramoto oscillators and the nonlocally coupled FitzHugh–Nagumo model. Results show that the control is independent of initial conditions and coupling schemes. Not only the single-headed chimera, but also the multi-headed chimera and even the alternating chimera can be obtained by the method, and only the desired position needs to be changed. Beyond that, we discuss the influence of hyper-parameters, demonstrate the universality of the method to network sizes, and show that the proposed method can stabilize the drift of chimera and prevent its collapse in small networks.