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Recent advances in artificial intelligence technology and perception components have promoted the rapid development of autonomous vehicles. However, as safety‐critical software, autonomous driving systems often make wrong judgments, seriously threatening human and property safety. LiDAR is one of the most critical sensors in autonomous vehicles, capable of accurately perceiving the three‐dimensional information of the environment. Nevertheless, the high cost of manually collecting and labeling point cloud data leads to a dearth of testing methods for LiDAR‐based perception modules. To bridge the critical gap, we introduce MetaLiDAR, a novel automated metamorphic testing methodology for LiDAR‐based autonomous driving systems. First, we propose three object‐level metamorphic relations for the domain characteristics of autonomous driving systems. Next, we design three transformation modules so that MetaLiDAR can generate natural‐looking follow‐up point clouds. Finally, we define corresponding evaluation metrics based on metamorphic relations. MetaLiDAR automatically determines whether source and follow‐up test cases meet the metamorphic relations based on the evaluation metrics. Our empirical research on five state‐of‐the‐art LiDAR‐based object detection models shows that MetaLiDAR can not only generate natural‐looking test point clouds to detect 181,547 inconsistent behaviors of different models but also significantly enhance the robustness of models by retraining with synthetic point clouds. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is a mild, environmentally friendly, and versatile oxidizer. The current main production process, the anthraquinone method, has high energy consumption and pollution. However, the photocatalytic production of H2O2 is considered to be a green and sustainable process. In this paper, the research progress of photocatalytic production of H2O2 was reviewed. Firstly, the basic principle of photocatalytic production of H2O2 and the three production pathways, namely, oxygen reduction, water oxidation, and dual-channel were introduced. Then, advanced photocatalysts for H2O2 production were introduced with emphasis. From the reactants and products, several new reaction systems and improvement strategies were introduced, including the construction of a spontaneous system without a sacrifice agent, a gas–liquid–solid three-phase system, and inhibition of H2O2 decomposition. The in-situ applications of photocatalytic H2O2 production in the environmental field, including in-situ disinfection and in-situ degradation of pollutants are discussed. Finally, the research progress and future research directions in this field are summarized and prospected. [ABSTRACT FROM AUTHOR]

Based on the ultrafast and extremely strong interaction between laser pulses and materials, ultrafast laser irradiation can break the solid solubility constraints and enable hyperdoping of impurities. This process overcomes the bandgap constraints of crystalline silicon, resulting in heightened absorption across a broad spectral range spanning from ultraviolet to infrared wavelengths, therefore commonly referred to as black silicon (b‐Si). The b‐Si demonstrates significant changes in optoelectronic properties, making it highly promising for applications in silicon photonics. Specifically, b‐Si photodetectors exhibit distinct advantages in terms of high photoelectric gain at low voltage, ultrabroadband spectral responsivity, large dynamic range, and suitability for operation over a wide temperature range. These properties address the limitations of traditional silicon photodetectors, showcasing great potential for applications in optoelectronic integration, artificial intelligence, information technology, energy devices, and beyond. This review focuses on b‐Si achieved through ultrafast laser processing, with a special emphasis on its applications in photodetectors. The mechanism of ultrafast laser irradiation and the properties of hyperdoped silicon are discussed. Then, the research progresses and state‐of‐the‐art b‐Si photodetectors are introduced, as well as working mechanism and potential application expansion. Finally, the development prospects of b‐Si photodetectors based on ultrafast laser hyperdoping are predicted. [ABSTRACT FROM AUTHOR]

We report that the use of a hydrogen-bonded pyrimidine-macrocycle complex can efficiently facilitate the threading of two bispyridinium ethylenes into four rings, as evidenced by X-ray crystallography of its precursor, offering a rare example of a doubly threaded [6]rotaxane in 91% yield. The unusual architecture is found to be stable with no dethreading despite the large ring size of the macrocycle with respect to the stopper. [ABSTRACT FROM AUTHOR]

A new Mg-4Zn X Ti-6Al-4V (TC4, of 0, 1, and 3 wt.%) alloy was successfully fabricated by a simple and low-cost gravity casting method and heat treatment at 150 °C for 24 h. The composite was examined by XRD, uniaxial tests, FESEM/EDS, potentiostat/EIS, and immersion tests for the material's microstructures, mechanical properties, electrochemical characteristics, and corrosion resistance. Experimental results indicate that heat treatment enables the precipitation of Zn along the Mg grain boundaries and drives the co-precipitation of Al around the TC4 particles and nearby grain boundaries. Uniaxial tensile tests reveal that TC4 reinforces the Mg-Zn matrix material with higher elastic modulus, ultimate tensile stress, and toughness. The heat treatment further enhanced these mechanical properties. Electrochemical tests show that 1 wt.% TC4 composite exhibits the highest open circuit potential among all tested samples, which implies the 1 wt.% TC4-added Mg-Zn is better resistant to the oxidation of the essential metals Mg, Zn, and Al. The immersion tests in the HBSS solution further show that the 1 wt.% TC4 composite has the lowest rise of pH values after 14 days, and EDS for the corroded surface signifies that Mg is the main element vulnerable to oxidation by corrosion. [ABSTRACT FROM AUTHOR]

This study investigates the effects of zinc (4 wt.%) and severe plastic deformation on the mechanical properties of AZ61 magnesium alloy through the stir-casting process. Severe plastic deformation (Equal Channel Angular Pressing (ECAP)) has been performed followed by T4 heat treatment. The microstructural examinations revealed that the addition of 4 wt.% Zn enhances the uniform distribution of β-phase, contributing to a more uniformly corroded surface in corrosive environments. Additionally, dynamic recrystallization (DRX) significantly reduces the grain size of as-cast alloys after undergoing ECAP. The attained mechanical properties demonstrate that after a single ECAP pass, AZ61 + 4 wt.% Zn alloy exhibits the highest yield strength (YS), ultimate compression strength (UCS), and hardness. This research highlights the promising potential of AZ61 + 4 wt.% Zn alloy for enhanced mechanical and corrosion-resistant properties, offering valuable insights for applications in diverse engineering fields. [ABSTRACT FROM AUTHOR]

The development of efficient and selective organic synthetic approaches for complex molecules has garnered significant attention due to the need for precise control over molecular structures and functions. Rotaxanes, a type of mechanically interlocked molecules (MIMs), have shown promising applications in various fields including sensing, catalysis, and material science. However, the highly selective synthesis of oligo[n]rotaxanes (mostly n≥3) through controlling host‐guest complexation and supramolecular threading assembly process still remains an ongoing challenge. In particular, the utilization of two‐dimensional (2D) macrocycles with structural shape‐persistency for the synthesis of oligo[n]rotaxanes is rare. In this concept, research on cooperatively threaded host‐guest complexation with hydrogen‐bonded (H‐bonded) aramide macrocycles and selective synthetic protocols of oligo[n]rotaxanes has been summarized. The high efficiency and selectivity in synthesis are ascribed to the synergistic interplay of multiple non‐covalent bonding interactions such as hydrogen bonding and intermolecular π–π stacking of macrocycles within the unique supramolecular structure of threaded host‐guest complexes. This review focuses on the latest progress in the concepts, synthesis, and properties of H‐bonded aramide macrocycle‐based oligorotaxanes, and presents an in‐depth outlook on challenges in this emerging field. [ABSTRACT FROM AUTHOR]

The key to intelligent fault diagnosis for transformer is to find relevant dissolved gas characteristics with the capability of representing different types of faults. However, the existing problem is that using a single traditional ratio method as the inputs of classification module cannot obtain high classification performance. Therefore, a fault diagnosis method for transformer based on neighborhood component analysis (NCA) and capuchin algorithm (CapSA)-regularized extreme learning machine (RELM) is proposed. Firstly, 21-dimensional features of the oil-immersed transformer are extracted based on the traditional ratio methods such as IEC three-ratio and Roger's ratio. Secondly, The NCA is used to select the feature to obtain an effective 6-dimensional feature. Then, these features are utilized as the input of the RELM model for training, and the parameters of model are optimized by CapSA. Finally, the feasibility and validity of the proposed method are verified by actual data sets collected from previous publications. The experimental results show that the proposed method has higher diagnostic precision and stability. [ABSTRACT FROM AUTHOR]

This work presents a novel strategy to model the coexistence of HELP & HEDE mechanisms. The proposed method accounts for ductile and brittle damage with a competitive fracture criterion to describe the competition effect between HELP & HEDE mechanisms. The cooperation aspect is addressed by a dislocation-enhanced hydrogen accumulation model, which agrees with the HELP-mediated HEDE mechanism. The tensile, fracture toughness, and threshold stress intensity factor tests are simulated in different hydrogen environments. The results demonstrate that the proposed method reproduces the hydrogen-dependent ductile to brittle transition phenomenon. Under different hydrogen conditions, the dominating damage mechanism and degradation trends agree with experimental observations. Furthermore, for the investigated 4130 steel, the predicted value of fracture toughness and threshold stress intensity factor match the experiment results. The difference in damage kinetics inherent in the two test methods is captured, which supports the rationality of the proposed strategy for HELP and HEDE interaction. [Display omitted] • Competitive & Cooperative ductile-brittle damage model on HELP & HEDE interplay. • Predicted Hydrogen embrittlement features match experimental observations. • K JC and K THa prediction outputs match experiment values. • Difference in hydrogen damage kinetics in different test methods captured. [ABSTRACT FROM AUTHOR]

Aims: Laparoscopic distal pancreatectomy (LDP) and laparoscopic central pancreatectomy (LCP) are two surgical methods that can remove pancreatic neck lesions. However, their benefits remain controversial. We aimed to compare the benefits and limitations of LDP and LCP. Methods: In total, 50 patients who underwent LDP (n = 34) or LCP (n =16) between January 2014 and November 2019 were retrospectively reviewed using our database. We analyzed their preoperative characteristics, operative data, pathological features, and postoperative outcomes. Results: The baseline features of patients did not differ significantly between the two groups (P < 0.05). Compared with the LDP group, the LCP group showed significantly prolonged operation time (392 ± 144 vs. 269 ± 130 min, P = 0.007), time to oral intake (3.8 ± 1.3 vs. 2.8 ± 0.9 days, P = 0.017), and hospital stay (19.6 ± 5.1 vs. 15.4 ± 4.1 days, P = 0.008) as well as increased hospital expenses (10.1 ± 6.2 vs. 6.6 ± 1.5 WanRMB, P = 0.023). However, no significant differences were observed in conversion rate (0/16 vs. 0/34), blood loss (154 ± 93 vs. 211 ± 170 mL, P = 0.224), postoperative white blood cell count (10.3 ± 2.7 vs. 11.1 ± 3.1, P = 0.432), first random blood glucose level after operation (8.2 ± 2.1 vs. 8.6 ± 2.6 mmol/L, P = 0.696), and ascites amylase level on day 3 after operation (5212 [3110–14,176] vs. 3142 [604–13,761] U/L, P = 0.167) between the two groups. Moreover, no significant differences were noted in the incidence of postoperative diabetes (1/16 vs. 5/34) between the two groups. However, LCP was associated with significantly higher incidences of pancreatic fistula grades B and C (P = 0.005) and postoperative hemorrhage (P = 0.031). Conclusion: Compared with the LCP, LDP is a useful and safer technique for benign or low-grade malignant tumors in the pancreatic neck. [ABSTRACT FROM AUTHOR]

Aims: Laparoscopic distal pancreatectomy (LDP) and laparoscopic central pancreatectomy (LCP) are two surgical methods that can remove pancreatic neck lesions. However, their benefits remain controversial. We aimed to compare the benefits and limitations of LDP and LCP. Methods: In total, 50 patients who underwent LDP (n = 34) or LCP (n =16) between January 2014 and November 2019 were retrospectively reviewed using our database. We analyzed their preoperative characteristics, operative data, pathological features, and postoperative outcomes. Results: The baseline features of patients did not differ significantly between the two groups (P < 0.05). Compared with the LDP group, the LCP group showed significantly prolonged operation time (392 ± 144 vs. 269 ± 130 min, P = 0.007), time to oral intake (3.8 ± 1.3 vs. 2.8 ± 0.9 days, P = 0.017), and hospital stay (19.6 ± 5.1 vs. 15.4 ± 4.1 days, P = 0.008) as well as increased hospital expenses (10.1 ± 6.2 vs. 6.6 ± 1.5 WanRMB, P = 0.023). However, no significant differences were observed in conversion rate (0/16 vs. 0/34), blood loss (154 ± 93 vs. 211 ± 170 mL, P = 0.224), postoperative white blood cell count (10.3 ± 2.7 vs. 11.1 ± 3.1, P = 0.432), first random blood glucose level after operation (8.2 ± 2.1 vs. 8.6 ± 2.6 mmol/L, P = 0.696), and ascites amylase level on day 3 after operation (5212 [3110–14,176] vs. 3142 [604–13,761] U/L, P = 0.167) between the two groups. Moreover, no significant differences were noted in the incidence of postoperative diabetes (1/16 vs. 5/34) between the two groups. However, LCP was associated with significantly higher incidences of pancreatic fistula grades B and C (P = 0.005) and postoperative hemorrhage (P = 0.031). Conclusion: Compared with the LCP, LDP is a useful and safer technique for benign or low-grade malignant tumors in the pancreatic neck. [ABSTRACT FROM AUTHOR]

The vibration isolator is a key part of many ultra-precision machines and measuring apparatus. Magnetic suspension vibration isolators (MSVIs) will have excellent application prospects in these instruments to restrain external oscillations. So this paper firstly proposes a new basic configuration of MSVI. Then, in order to study the mechanical characteristics of the MSVI, an analytical expression of the magnetic force is established. The effectiveness of which is demonstrated by the experiment and finite element analysis (FEA). The stiffness of the MSVI is obtained by the derivative of the established analytical magnetic force. Both the axial magnetic force and stiffness appear strong nonlinearity when the inner ring moves at both ends of the fixed outer ring. While the inner ring travels in the middle of the fixed outer one, the axial magnetic force and stiffness indicate approximate linearity with enough bearing capacity. Furthermore, parametric analysis, based on the created magnetic force and stiffness, is performed. The analytical results show that the axial magnetic stiffness may achieve a zero or even negative stiffness value in this range at some size dimensions. The MSVI appears to have a negative stiffness characteristic. More importantly, if a linear and nonlinear positive stiffness spring is combined with the MSVI, it can increase the load capacity of the MSVI. As an example study, the vibration isolation performance of the MSVI is analyzed. The vibration isolation calculation and experiment with the zero stiffness MSVI will be the further focus of the paper. [ABSTRACT FROM AUTHOR]

AFM has a wide range of applications in nanostructure scanning imaging and fabrication. The wear of AFM probes has a significant impact on the accuracy of nanostructure measurement and fabrication, which is particularly significant in the process of nanomachining. Therefore, this paper focuses on the study of the wear state of monocrystalline silicon probes during nanomachination, in order to achieve rapid detection and accurate control of the probe wear state. In this paper, the wear tip radius, the wear volume, and the probe wear rate are used as the evaluation indexes of the probe wear state. The tip radius of the worn probe is detected by the nanoindentation Hertz model characterization method. The influence of single machining parameters, such as scratching distance, normal load, scratching speed, and initial tip radius, on probe wear is explored using the single factor experiment method, and the probe wear process is clearly divided according to the probe wear degree and the machining quality of the groove. Through response surface analysis, the comprehensive effect of various machining parameters on probe wear is determined, and the theoretical models of the probe wear state are established. [ABSTRACT FROM AUTHOR]

Idesia polycarpa Maxim is a native dioecious tree from East Asia cultivated for its fruits and as an ornamental plant throughout temperate regions. Given the economic potential, comparative studies on cultivated genotypes are of current interest. This study aims to discover the dynamic changes and potential functions of endogenous hormones in I. polycarpa, as well as the differences in endogenous hormone contents in different growth stages among different I. polycarpa provenances. We used High-Performance Liquid Chromatography (HPLC) to measure and compare the levels of abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellin A3 (GA3), and trans-Zeatin-riboside (tZR) in the leaves, flowers, and fruits of I. polycarpa from various provenances between April and October. Our findings indicated that changes in the ABA and GA3 content of plants from Jiyuan and Tokyo were minimal from April to October. However, the levels of these two hormones in Chengdu plants vary greatly at different stages of development. The peak of IAA content in the three plant materials occurred primarily during the early fruit stage and the fruit expansion stage. The concentration of tZR in the three plant materials varies greatly. Furthermore, we discovered that the contents of endogenous hormones in I. polycarpa leaves, flowers, and fruits from Chengdu provenances were slightly higher than those from Tokyo and Jiyuan provenances. The content of IAA was higher in male flowers than in female flowers, and the content of ABA, GA3, and tZR was higher in female flowers than in male flowers. According to the findings, the contents of these four endogenous hormones in I. polycarpa are primarily determined by the genetic characteristics of the trees and are less affected by cultivation conditions. The gender of I. polycarpa had a great influence on these four endogenous hormones. The findings of this study will provide a theoretical foundation and practical guidance for artificially regulating the flowering and fruiting of I. polycarpa. [ABSTRACT FROM AUTHOR]

The Neogene is an important period for studying the onset of subduction, with numerous subduction zones forming in the western Pacific, including the Ryukyu, Manila, Philippine, North Sulawesi, Halmahera, New Britain, Solomon, and New Hebrides subduction zones. However, studies on these subduction zones are relatively independent, so it is important to conduct systematic comparative studies. In this paper, we review the initiation models of Neogene subduction in the western Pacific, with the three typical types of subduction initiation models including polarity-reversal, induced subduction re-initiation, and non-inherited subduction initiation to form new ruptures. In addition, the parameters of different subduction zones are collated to form five categories: basic features, subducting plate features, upper plate features, kinematic features, and subsequent activity. The regularity of the subduction processes, the specificity of the different subduction cases, and the possible constraints between the subduction initiation types and the characteristics of the subduction zone parameters are discussed and analyzed. The compiled dataset of the subduction zone parameters can provide data support for related studies. [ABSTRACT FROM AUTHOR]

Online education brings more possibilities for personalized learning, in which identifying the cognitive state of learners is conducive to better providing learning services. Cognitive diagnosis is an effective measurement to assess the cognitive state of students through response data of answering the problems(e.g., right or wrong). Generally, the cognitive diagnosis framework includes the mastery of skills required by a specified problem and the aggregation of skills. The current multi-skill aggregation methods are mainly divided into conjunctive and compensatory methods and generally considered that each skill has the same effect on the correct response. However, in practical learning situations, there may be more complex interactions between skills, in which each skill has different weight impacting the final result. To this end, this paper proposes a generalized multi-skill aggregation method based on the Sugeno integral (SI-GAM) and introduces fuzzy measures to characterize the complex interactions between skills. We also provide a new idea for modeling multi-strategy problems. The cognitive diagnosis process is implemented by a more general and interpretable aggregation method. Finally, the feasibility and effectiveness of the model are verified on synthetic and real-world datasets. [ABSTRACT FROM AUTHOR]

2.25Cr-1Mo-0.25 V steel has been widely used to manufacture hydro-processing equipment operating under harsh environments for its good creep performance. Warm bending, a common fabricating process of 2.25Cr-1Mo-0.25 V steel ring shells, inevitably changes the creep property of 2.25Cr-1Mo-0.25 V steel, but its detailed effect still remains obscure. In this work, we experimentally investigated the impact of warm bending on the microstructure and creep behavior of 2.25Cr-1Mo-0.25 V steel. First, a series of creep rupture tests were carried out at 482 °C and 350 MPa, in which test materials were extracted from an actually fabricated ring shell and its raw plate. Thereafter, the microstructures of test materials were semi-quantitatively analyzed by various characterization techniques, such as electron backscatter diffraction (EBSD) and three-dimensional high-resolution X-ray computed tomography (3D μ-XCT). Finally, warm forming induced microstructural degradation as well as their implication for creep was discussed in detail. Creep rupture tests showed that warm bending leads to a significant decrease in creep lifetime at the surface region of virgin plate but a slight decline at the central region of virgin plate. An inhomogeneous creep resistance distribution was thereby revealed along the thickness direction of the ring shell, which could not be completely eliminated by subsequent tempering at 705 °C for 8 h. Moreover, microstructural observations demonstrated that warm deformation leads to multiple microstructural deterioration, including carbide coarsening, ferrite matrix softening, void defect increasing, etc. Their combined action appears to accelerate the creep fracture behavior of 2.25Cr-1Mo-0.25 V steel. This work will contribute to the long-term safety and integrity assessment of 2.25Cr-1Mo-0.25 V steel structures. [ABSTRACT FROM AUTHOR]

A commutation torque ripple suppression strategy for the brushless DC motor (BLDCM) with commutation time is proposed. First, a torque model considering back electromotive force (back‐EMF) variation is presented, and the cause of commutation torque ripple is analysed. The results show that the commutation torque ripple of BLDCM is inevitable even if the non‐commutation current remains steady. On this basis, the influence and quantitative relationships of non‐commutation current and commutation time on commutation torque ripple are studied. Furthermore, two impact factors are proposed to comprehensively consider their effects on commutation torque ripple. The three‐phase windings are modulated in the commutation process at individual duty cycles. The comprehensive optimisation index of commutation torque ripple for different working conditions is obtained by calculating the relative relationship of the impact factors. The optimisation index determines the proper modulation duty cycles. Therefore, the motor parameters and working conditions do not limit the strategy. Finally, the experimental results verify the correctness of the theoretical analysis and the feasibility of the proposed strategy. The proposed strategy can reduce the commutation torque ripple by 16.28% and 21.80% and shorten the commutation time by 50.00% and 36.67% at low speed and high speed, respectively, compared with the conventional strategy. [ABSTRACT FROM AUTHOR]

Halide perovskites-based solar cells are drawing significant attention due to their high efficiency, versatility, and affordable processing. Hence, halide perovskite solar cells have great potential to be commercialized. However, the halide perovskites (HPs) are not stable in an ambient environment. Thus, the instability of the perovskite is an essential issue that needs to be addressed to allow its rapid commercialization. In this work, WS2 nanoparticles (NPs) are successfully implemented on methylammonium lead iodide (MAPbI3) based halide perovskite solar cells. The main role of the WS2 NPs in the halide perovskite solar cells is as stabilizing agent. Here the WS2 NPs act as heat dissipater and charge transfer channels, thus allowing an effective charge separation. The electron extraction by the WS2 NPs from the adjacent MAPbI3 is efficient and results in a higher current density. In addition, the structural analysis of the MAPbI3 films indicates that the WS2 NPs act as nucleation sites, thus promoting the formation of larger grains of MAPbI3. Remarkably, the absorption and shelf life of the MAPbI3 layers have increased by 1.7 and 4.5-fold, respectively. Our results demonstrate a significant improvement in stability and solar cell characteristics. This paves the way for the long-term stabilization of HPs solar cells by the implementation of WS2 NPs. [ABSTRACT FROM AUTHOR]

Designing the high-performance, high-subsonic airfoils suitable for different Reynolds number flow is the major challenge for high-altitude long-endurance drones and ultra-high altitude solar aircraft. To overcome the difficulties, this paper proposed a set of aerodynamic optimization design methods that combine the improved category shape function transformation method, parallel computational fluid dynamics, and an improved whale optimization algorithm. This approach achieves high modeling accuracy, computational efficiency, and strong optimization ability. Verification using single-peak, multi-peak, and fixed-dimensional test functions demonstrates that the improved whale optimization algorithm has significantly enhanced optimization capabilities compared with the conventional whale optimization, particle swarm optimization, and gravity search algorithms. Numerical simulations are used to analyze the internal flow mechanisms before and after airfoil optimization under different Reynolds numbers. The results show that, compared with the original airfoil, the optimized airfoil has front loading characteristics that effectively reduce the adverse pressure gradient of the rear part of suction surface, promoting the transition in this region. The reduced adverse pressure gradient also inhibits the development and growth of laminar separation bubbles and slows down the growth of the boundary layer displacement thickness, thereby reducing wake mixing loss and improving the aerodynamic performance. [ABSTRACT FROM AUTHOR]

Histone deacetylase 4/5 (HDAC4/5) are essential for regulating metabolic gene expression; AMPKα2 regulates HDAC4/5 activity and the expression of MuRF1 during exercise. In this study, we used wild-type and AMPKα2−/− mice to explore the potential regulatory relationship between AMPKα2 and HDAC4/5 expression during exercise. Firstly, we fed C57BL/6J mice with high-fat diet for 8 weeks to assess the effects of high-fat diet on skeletal muscle metabolism and HDAC4/5 expression. We then performed a 6-week treadmill exercise on both wild-type and AMPKα2−/− mice. After exercise, the expressions of HDAC4/5 were examined in both gastrocnemius and soleus. The citrate synthase activity and proteins involved in skeletal muscle oxidative process were assessed. To determine the relationship of HDAC4/5 and skeletal muscle oxidative capacity, citrate synthase activity was assessed after silencing HDAC4/5. Moreover, HDAC5 ubiquitination and the association of MuRF1 to HDAC5 were also investigated. Our results showed that 6-week exercise increased the skeletal muscle oxidative capacity and decreased HDAC4/5 expression only in soleus. HDAC5 silencing increased C2C12 cell oxidative capacity. Proteasome inhibition by MG132 abolished exercise-induced HDAC5 degradation mediated by MuRF1–ubiquitin–proteasome system. However, the ubiquitin–proteasome system (UPS) did not dominantly account for exercise-induced HDAC4 degradation. Exercise upregulated MuRF1–HDAC5 association in wild-type mice but not in AMPKα2−/− mice. Our results revealed that 6-week exercise increased the skeletal muscle oxidative capacity and promoted HDAC5 degradation in soleus through the UPS, MuRF1-mediated HDAC5 ubiquitination. Although AMPKα2 played a partial role in regulating MuRF1 expression and HDAC5 ubiquitination, exercise-induced HDAC5 degradation did not fully depend on AMPKα2. [ABSTRACT FROM AUTHOR]

Software defect prediction (SDP) is an important technology which is widely applied to improve software quality and reduce development costs. It is difficult to train the SDP model when software to be test only has limited historical data. Cross-project defect prediction (CPDP) has been proposed to solve this problem by using source project data to train the defect prediction model. Most of CPDP methods build defect prediction models based on the similarity of feature space or data distance between different projects. However, when the target project has a small amount of label data, these methods usually do not consider this part of data information. Therefore, when the distribution between source project and target project is quite different, these methods are difficult to achieve good prediction performance. To solve this problem, this paper proposes a CPDP method based on a semisupervised clustering (namely, Tsbagging). Tsbagging has two stages; in the first stage, we cluster to the source project data based on the limited labeled data in the target project and assign different weights to these source project data according to the clustering results. In the second stage, we use bagging method to train the prediction model based on the weight assigned in the first stage. The experimental results show that the performance achieved by Tsbagging is better than other existing SDP methods. [ABSTRACT FROM AUTHOR]

This paper studies a manufacturer's selling channel structure choice in a supply chain wherein the firms may concern about consumer surplus. In addition, the retailer can make the demand-enhancement investment, the effect of which may spill over to the manufacturer, subsequently altering the manufacturer's selling channel structure choice among the reselling channel (mode R), the direct-selling channel (mode M), and the dual channels (mode D). Several intriguing results are obtained. First, when the manufacturer concerns about consumer surplus, the manufacturer prefers mode R if both the retailer's investment cost and the manufacturer's concern for consumer surplus are either high or low, while choosing mode M if the investment cost is high and the concern for consumer surplus is relatively low. Conversely, the manufacturer may not choose mode M when the retailer concerns about consumer surplus. Besides, whether the manufacturer or the retailer concerns about consumer surplus, only mode R may arise as the jointly preferred channel choice for the firms. Second, mode R is more profitable for the supply chain when the manufacturer's (retailer's) concern for consumer surplus is sufficiently high, because the sales competition is weaker and the retailer's investment incentive is stronger in mode R. Third, mode M cannot be optimal for consumer surplus and social welfare due to the absence of the retailer's demand-enhancement investment. Finally, the manufacturer's (retailer's) increasing concern for consumer surplus does not necessarily improve consumer surplus and social welfare because of the effect of investment cost on the manufacturer's equilibrium channel structure strategy. • Manufacturer channel choice with dual-purpose firms and demand investment is studied. • Mode R may arise as the equilibrium for dual-purpose firms under certain conditions. • The manufacturer may abandon mode M when the retailer cares about consumer surplus. • The manufacturer's dual-purpose concern does not always favor consumer surplus. [ABSTRACT FROM AUTHOR]

This study explores the synthesis of AZ61 alloy composite powders with Co-Ni additives using high-energy ball milling (HEBM). The powders are extensively characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) to analyze their morphology, composition, structure, and bonding. The hydrogen storage capacity of the powders is measured using a Sievert's-type system revealing diverse capacities. For AZ61 alloy with Ni additive (2 µm), it absorbs 90% of the capacity in 410 s, showing an activation energy of 91.46 kJmol−1 and displays Mg 2 NiH 4 as an intermediate. On the other hand, AZ61 alloy with Co additive requires 576 s to absorb 90% of the capacity, showing an activation energy of 117.23 kJmol−1 and Mg 2 CoH 5 as an intermediate. When a mixture of Ni and Co is added to AZ61 alloy, it achieves 90% capacity absorption in 300 s. In the absence of additives, AZ61 alloy (15 µm) reaches 90% capacity absorption in 1600 s. The incorporation of additives significantly reduces the activation energy. A correlation between longer absorption times and larger activation energies provides valuable insights into the storage kinetics and activation energy associated with the hydrogen absorption/desorption process. [Display omitted] • The addition of Ni, Co, and a mixture of Ni and Co to the AZ61 alloy enhances its hydrogen storage capacity compared to the alloy without additives. • The hydrogen storage capacities of the AZ61 alloy with Ni, Co, and Ni-Co additives were measured to be 4.5 wt%, 5.316 wt%, and 5.14 wt%, respectively. • The presence of specific reaction intermediates, such as Mg 2 NiH 4 and Mg 2 CoH 5 , was confirmed through XRD patterns, indicating their role in the hydrogen absorption process and promoting reversibility and cycle stability. • The activation energy for hydrogen absorption in the AZ61 alloy with Co additive was found to be 117.23 kJ/mol while that of Ni was 91.46 kJ/mol. • Kinetics to achieve 90% capacity: AZ61 alloy with Ni additive requiring 410 s, the alloy with Co additive requiring 576 s, the alloy with Ni and Co mixture requiring 300 s, and the alloy without additives requiring 1600 s. These results highlight the influence of additive composition on the kinetics of hydrogen absorption. [ABSTRACT FROM AUTHOR]

• A quasi-unidirectional spatiotemporal mode-locked bidirectional tunable output has been achieved in an erbium-doped fiber laser. • Capable of achieving tunable outputs of both CSs and BSs types in both of the dominant CCW and dominant CW directions simultaneously. • Both of the STML conventional solitons and the STML bound solitons are obtained with a similar tunable wavelength from ∼1.56 μm to ∼1.58 μm. In this letter, we have demonstrated the realization of the wavelength-tunable spatiotemporal mode-locked (STML) operation in an Er-doped partial multimode fiber laser without the intracavity isolator. The laser adopts an all-fiber structure and the saturable absorption effect is attributed to nonlinear multimode interference (NL-MMI) from the single mode fiber-graded index multimode fiber-single mode fiber (SMF-GIMF-SMF) design. The STML laser can operate in the quasi-unidirectional regime with an emission strength difference of larger than 30 dB for the two counter-propagating lasers. And the switching between the dominating operating directions in the clockwise (CW) or counter-clockwise (CCW) directions can be easily achieved by adjusting the MM polarization controller (PC). Both STML conventional solitons (CSs) and the STML soliton molecules are obtained with a similar tunable wavelength from ∼1.56 μm to ∼1.58 μm for the opposite operating directions. Furthermore, the spatial dynamics of the STML soliton are also investigated in detail. The experimental results are of great help for us to explore nonlinear spatiotemporal dynamics and provide potential applications in fields of all-optical signal processing, fiber sensing and information coding. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) are potential bioelectrochemical devices that are now being researched for various emerging applications, such as treating wastewater with antibiotics removal. Ciprofloxacin (CIP) is a synthetic antibiotic that is commonly used to treat infections such as pneumonia and influenza. This work investigated the performance of dual-chambered MFCs with two different types of anodes to remove CIP and chemical oxygen demand (COD) and power production. The findings of the experiments revealed that the multiwall carbon nanotubes-coated graphite felt (MWCNT-GF) had a higher power density (1,512.9 mW/m2) and COD removal (95.4%) than the control graphite-felt anode (816.3 mW/m2 , COD removal 93.2%) under the same circumstances. Further, MFCs were also tested for four different concentrations with average CIP removal rate with MWCNT-coated GF anode to 58.575% and GF anode of 54.25%. Higher CIP removal rate and power performance of MWCNT-GF anodes are due to its macroporous structure, which promotes microbial interaction on the electrode surface. Also, it shows an additional effect of increasing extracellular electron transport. The findings suggest that a dual-chambered MFC operating with a MWCNT-GF anode is a highly effective means of achieving high power performance and CIP removal, with a broad range of application possibilities in bioelectrochemical systems. [ABSTRACT FROM AUTHOR]

A functionally structured catalyst was explored for ethanol steam reforming (ESR) to generate H2. Aluminum lathe waste strips were employed as the structured catalytic framework. The mixed metal oxide (Li-Al-O) was formed on the surface of Al lathe waste strips through calcination of the Li-Al-CO3 layered double hydroxide (LDH), working as the support for the formation of Ni catalyst nanoparticles. NaOH and NaHCO3 titration solutions were, respectively, used for adjusting the pH of the NiCl2 aqueous solutions at 50 °C when developing the precursors of the Ni-based catalysts forming in-situ on the Li-Al-O oxide support. The Ni precursor on the Al structured framework was reduced in a H2 atmosphere at 500 °C for 3 h, changing the hydroxide precursor into Ni nanoparticles. The titration agent (NaOH or NaHCO3) effectively affected the physical and chemical characterizations of the catalyst obtained by the different titrations. The ESR reaction catalyzed by the structured catalysts at a relatively low temperature of 500 °C was studied. The catalyst using NaHCO3 titration presented good stability for generating H2 during ESR, achieving a high rate of H2 volume of about 122.9 L/(gcat·h). It also had a relatively low acidity on the surface of the Li-Al-O oxide support, leading to low activity for the dehydration of ethanol and high activity to H2 yield. The interactions of catalysts between the Ni precursors and the Li-Al-O oxide supports were discussed in the processes of the H2 reduction and the ESR reaction. Mechanisms of carbon formation during the ESR were proposed by the catalysts using NaOH and NaHCO3 titration agents. [ABSTRACT FROM AUTHOR]

In this work, a practical numerical model with few parameters was proposed for the prediction of environmental hydrogen embrittlement. The proposed method adopts hydrogen enhanced plasticity-based mechanism in a fracture strain model to describe hydrogen embrittlement. Fracture toughness degradation of three commercial steels SA372J70, AISI4130 and X80 in high pressure hydrogen environment were investigated. Firstly, governing equations for hydrogen distribution and material damage evolution was established. Hydrogen enhanced localized flow softening effect was coupled within fracture strain dependency on stress triaxiality. Then, the numerical implementation and identification process of model parameters was described. Model parameters of the investigated steels were determined based on experiment results from literatures. Finally, with the calibrated model, fracture toughness reduction of the steels was predicted in a wide range of hydrogen pressure. The prediction results were compared with experimental results. Reasonable accuracy was reached. The proposed method is an attempt to reach balance between physical accurate prediction and engineering practicality. It is promising to provide a simplified numerical tool for the design and fit for service evaluation of hydrogen storage vessels. • Hydrogen embrittlement prediction model with few parameters was proposed. • Identification of model parameters with a few support of experiments. • Simplified Fracture toughness prediction model with acceptable accuracy. [ABSTRACT FROM AUTHOR]

Background: Sleep health and obesity may affect the risk of female infertility. However, few studies focused on the interaction of obesity and sleep health on the female infertility risk. This study aimed to evaluate the combined impact of trouble sleeping / sleep duration and overweight/obesity/ abdominal obesity on the risk of female infertility. Methods: The data for this cross-sectional study was obtained from National Health and Nutritional Examination Survey, which provided information on trouble sleeping, sleep duration, overweight/obesity, abdominal obesity, and confounding factors. Adopted weighted univariate and multivariate logistic regression models to explore the relationship between trouble sleeping, sleep duration, overweight/obesity, abdominal obesity, and the risk of infertility, respectively, and the combined effect of trouble sleeping and overweight/obesity, trouble sleeping and abdominal obesity, sleep duration and overweight/obesity, sleep duration and abdominal obesity, on the female infertility risk. Results: This study included a total of 1,577 women, and 191 were diagnosed with infertility. Women with infertility had a higher proportion of people with overweight/obesity, abdominal obesity, sleep duration ≤ 7 h and trouble sleeping than those with non-infertility. The result indicated that trouble sleeping [odds ratio (OR) = 2.25, 95% confidence intervals (CI): 1.49–3.39], sleep duration ≤ 7 h (OR = 1.59, 95% CI: 1.03–2.48), and the combined impact of abdominal obesity and trouble sleeping (OR = 2.18, 95% CI: 1.28–3.72), abdominal obesity and sleep duration ≤ 7 h (OR = 2.00, 95% CI: 1.17–3.40), overweight/obesity and trouble sleeping (OR = 2.29, 95% CI: 1.24–4.26), and overweight/obesity and sleep duration ≤ 7 h (OR = 1.88, 95% CI: 1.01–3.49) were associated with increased odds of infertility, respectively. Conclusion: There was combined effects of trouble sleeping/sleep duration ≤ 7 h and overweight/obesity/ abdominal obesity on increased odds of female infertility. [ABSTRACT FROM AUTHOR]

• The titanium hyperdoped black silicon is achieved with high absorption over the range of 200 ∼ 2700 nm. • The b-Si:Ti photodetector exhibits high photocurrent and photoresponsivity under low reverse bias voltages. • The photoconductive gain is achieved across a broadband spectral range. • The photodetector exhibits a stable sub-bandgap photon sensitivity. Silicon, as one of the most essential semiconducting materials, is widely applied in various photodetection applications due to its high portability, convenient preparation, and compatibility with conventional complementary metal–oxide–semiconductor technology. Nowadays, black silicon, prepared by enforcing ultrafast laser micro-structuring and hyperdoping techniques, has received considerable attention for developing next-generation silicon photonics and silicon optoelectronics devices. In this work, high-comprehensive-property black silicon photodetectors with broadband spectral responsivity and high gain were achieved by femtosecond laser irradiation and titanium hyperdoping. The proposed device can respond to the incident light from 400 nm to at least 1550 nm, demonstrating a high responsivity of 40.59 A/W for 950 nm under the application of −5 V bias, and the corresponding detectivity can reach 3.61 × 1012 cm·Hz1/2W−1. Moreover, the fabricated photodetector exhibits a stable sub-bandgap photocurrent at 1550 nm, with an average responsivity of 3.42 mA/W by applying a −5 V bias. These improvements were achieved by the hyperdoping of titanium in silicon, which shows deep impurity levels, low electroactivity, and increased effective carrier lifetimes, as well as the formation of shallow n-i heterojunction and trapping centers induced by the femtosecond laser irradiation. Our work provides significant insights into the applications of black silicon in various optical-related fields, including weak and infrared photon detection, silicon photonic chips, remote sensing, and large-scale optoelectronic integration. [ABSTRACT FROM AUTHOR]

[Display omitted] • The current study is a combination of two recently trending technologies: MFC and additive manufacturing. • The impact of surface based vs truss based lattice structures on MFC power performance is studied. • Flow pattern is observed via experimental as well as CFD analysis. • Straight flow line should be avoided as it results in lower mixing efficiency. In an aim to scale up the microbial fuel cell (MFC), this research is a first attempt to investigate the impact of two lattice structures flow straighteners: gyroid and X lattice to compare with the conventional honeycomb flow straightener, fabricated via additive manufacturing. The study focused on assessing their effect on the degradation of domestic wastewater and power generation in a dual chamber recirculation MFC. Other than the geometry, structures were also tested at flow rates of 20 mL/min, 60 mL/min, and 100 mL/min. Our study found that MFC equipped with a gyroid structure flow straightener produced the highest power density of 2871.89mWm−2, followed by the X lattice flow straightener of 2626.56 mWm−2 and 2096.03 mWm−2 with honeycomb flow straightener. ANSYS simulations revealed that this increased power density is attributed to the enhanced mixing of wastewater. Traditional honeycomb-based flow straighteners showed straight streamlines, causing bacteria to settle and leading to lower output voltage. The novel X lattice and gyroid lattice designs ensured uniform substrate mixing, addressing the issue of substrate settling and consequently boosting the MFC's power performance. An optimized flow rate of 60 mL/min yielded the best output. Overall, this study successfully introduced two novel lattice structures for flow straighteners, demonstrating their potential in enhancing power performance and the scalability of this technology when produced using additive manufacturing. [ABSTRACT FROM AUTHOR]

Geothermal heat flow, as a parameter characterizing the Earth's thermal state, records deep thermodynamic processes. However, measurements of heat flow (HF) in the oceanic crust are relatively sparse and susceptible to surface activity such as hydrothermal circulation. We propose a machine learning approach to predict marine HF (MHF). We apply the random forest (RF) regression algorithm to train predictors capable of mapping multiple geological and geophysical features to MHF, thus enabling HF prediction in the global oceanic crust. We generate three data sets with different qualities of HF measurements for training. The best predictor has an accuracy of ~ 0.13 (normalized root mean squared error) or ~ 0.07 (normalized mean absolute error), and the predicted global oceanic crust HF map reflects the basic pattern of the MHF distribution. We find by comparison that the quality of HF measurement affects the prediction results. Then, we use a cross-prediction scheme to screen out the "underestimated" measured HF cases, which are mostly located in tectonic environments such as mid-ocean ridges and back-arc basins and show high spatial correlation with hydrothermal circulation. Furthermore, we conduct experimental calculations for the extent and proportion of underestimated cases in the oceanic part of a new global heat flow (NGHF) database; for example, the proportion of records with the degree of underestimation greater than 50% is approximately 30.8%. These calculations can provide reference information for the selection and application of MHF records in the NGHF database. [ABSTRACT FROM AUTHOR]

Purpose: Nasal irrigation is an effective method for alleviating several nasal symptoms and regular seawater-based nasal irrigation is useful for maintaining nasal hygiene which is essential for appropriate functioning of the nose and for preventing airborne particles including some pollutants, pathogens, and allergens from moving further in the respiratory system. However, safety studies on seawater-based nasal irrigation are scarce. In this study, the safety and efficacy of a diluted isotonic seawater solution (Stérimar Nasal Hygiene, SNH) in maintaining nasal homeostasis were evaluated in vitro. Methods: Safety was assessed by measuring tissue integrity via transepithelial electrical resistance (TEER). Efficacy was measured by mucociliary clearance (MCC), mucin secretion, and tissue re-epithelization (wound repair) assays. All assays were performed using a 3D reconstituted human nasal epithelium model. Results: In SNH-treated tissues, TEER values were statistically significantly lower than the untreated tissues; however, the values were above the tissue integrity limit. SNH treatment significantly increased MCC (88 vs. 36 µm/s, p < 0.001) and mucin secretion (1717 vs. 1280 µg/ml, p < 0.001) as compared to untreated cultures. Faster wound closure profile was noted upon pre-SNH treatment as compared to classical isotonic saline solution pre-treatment (90.5 vs. 50.7% wound closure 22 h after wound generation). Conclusion: SNH did not compromise the integrity of the nasal epithelium in vitro. Furthermore, SNH was effective for removal of foreign particles through MCC increase and for enhancing wound repair on nasal mucosa. [ABSTRACT FROM AUTHOR]

AZ61 magnesium alloy metal matrix composites (MMCs) with different weight percentages (0, 1 and 2) of micro-silicon carbide particles (SiCp) were fabricated using stir casting method. Effects of SiCp on the microstructural distributions, mechanical and fatigue properties, and fracture surfaces have been investigated. The microstructural observations of as-cast MMCs unveil the existence of primary α-Mg phase and the presence of large amount of β-Mg17Al12 secondary phase at grain boundary. The specimens are subjected to homogenization heat treatment at 410 °C for 24 h; the β-Mg17Al12 phases are significantly dissolved in the matrix grain boundaries which enhance the ductility and decrease the hardness compared with the as-cast materials. The addition of SiCp reinforcement led to improved yield strength (YS) and ultimate tensile strength (UTS) of AZ61/SiCp composite compared to the unreinforced alloy. The maximum values of YS and UTS have been attained at AZ61/1wt%SiCp composites. The enhancement of YS and UTS was due to the presence of a uniformly distributed reinforced SiCp, which depends on grain refinement of the matrix and strong interfacial bonding between the matrix and reinforcement. In the case of fatigue test results, the addition of SiCp reduced the fatigue life and strength of AZ61 alloy composite. However, addition of 1wt%SiCp showed good mechanical and fatigue properties compared to pure AZ61 magnesium alloy and AZ61/2wt%SiCp composite. Furthermore, the effects of addition of SiCp on the mechanical and fatigue properties of the composite were confirmed by using the scanning electron microscope observation of fracture surfaces. [ABSTRACT FROM AUTHOR]

This study examines the equilibrium channel structure strategy in a supply chain where a manufacturer can sell products to consumers via/on an online platform, and firms may focus on both profit and consumer surplus. We consider three supply chain channel structures: a reselling channel (mode R), wherein the platform acts as the reseller; an agency channel (mode A), wherein the platform acts as the marketplace; and a dual channel (mode D), wherein the platform acts as both the reseller and marketplace. This study explores the strategic effect of the dual-purpose concern on the co-opetition relationship of firms and derives ramifications for the optimal channel structure. First, the platform may abandon mode A when the manufacturer's consumer surplus concern is high, even if the commission rate is high. This is because the manufacturer's sales revenue may be harmed by the higher selling quantity and lower price resulting from the increased concern of consumer surplus in mode A. The manufacturer prefers mode D (mode R) only when the commission rate is low (high). However, the supply chain may prefer mode R (mode D) when the platform's consumer surplus concern is high (low) irrespective of the commission rate. Second, with dual-purpose firms, both the platform and manufacturer may prefer mode R (mode D) when the commission rate is medium and the platform's consumer surplus concern is high (low). Third, mode A is beneficial to consumer surplus and social welfare as long as agency selling is viable, which occurs when the consumer surplus concern and the commission rate are not too high; otherwise, mode D is the optimal choice, because it enables the supply chain to sell products to consumers in a more flexible way. Finally, the results are robust to a parsimonious dual-purpose platform, an imperfect competitive market, price competition with a dominant platform, multiple competing manufacturers, and a non-zero slotting fee. • The equilibrium strategy with an online platform and dual-purpose firms is studied. • Dual-purpose concern has a strategic effect on the firms' co-opetition relationship. • Sales aggressiveness effect and co-opetition alteration effect are identified. • Influences of the two effects above on firms' channel preferences are examined. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) stands out as a biomaterial with immense potential, primarily owing to its innate biodegradability. Conventional methods for manufacturing PLA encompass injection molding or additive manufacturing (AM). Yet, the fabrication of sizable medical devices often necessitates fragmenting them into multiple components for printing, subsequently requiring reassembly to accommodate the constraints posed by the dimensions of the AM platform. Typically, laboratories resort to employing nuts and bolts for the assembly of printed components into expansive medical devices. Nonetheless, this conventional approach of jointing is susceptible to the inherent risk of bolts and nuts loosening or dislodging amid the reciprocating movements inherent to sizable medical apparatus. Hence, investigation into the joining techniques for integrating printed components into expansive medical devices has emerged as a critical focal point within the realm of research. The main objective is to enhance the joint strength of PLA polymer rods using rotary friction welding (RFW). The mean bending strength of welded components, fabricated under seven distinct rotational speeds, surpasses that of the underlying PLA substrate material. The average bending strength improvement rate of welding parts fabricated by RFW with three-stage transformation to 4000 rpm is about 41.94% compared with the average bending strength of PLA base material. The average surface hardness of the weld interface is about 1.25 to 3.80% higher than the average surface hardness of the PLA base material. The average surface hardness of the weld interface performed by RFW with variable rotational speed is higher than the average surface hardness of the weld interface performed at a fixed rotating friction speed. The temperature rise rate and maximum temperature recorded during RFW in the X-axis of the CNC turning machine at the outer edge of the welding part surpassed those observed in the internal temperature of the welding part. Remarkably, the proposed method in this study complies with the Sustainable Development Goals due to its high energy efficiency and low environmental pollution. [ABSTRACT FROM AUTHOR]

• This paper used a combination of Computational Fluid Dynamics (CFD) and rotor dynamics to calculate the axial orbit and obtain axial orbit states that match experimental results. • This study is the first to investigate the reactor coolant pump's axial orbit under non-uniform inflow and analyze the reasons. Before this, few people paid attention to the influence of non-uniform inflow on rotor dynamic response. • The Detached Eddy Simulation (DES) turbulence model used in this paper calculated fluid pulsations at low frequencies that were very close to those obtained in the experiment, indicating strong calculation accuracy. In pressurized water reactors, a reactor coolant pump (RCP) is crucial for circulating coolant through the primary loop. However, in advanced passive (AP) reactors, the steam generator and RCP are not connected by a long pipeline, creating a transition section that leads to a non-uniform inflow at the pump inlet. The non-uniform inflow can affect the operational status of a pump, which in turn affects the motion state of the rotor. In this study, the variation of the axis orbit under non-uniform inflow was analyzed through experiments, and it was found that the shape of the axis orbit had undergone significant changes, and the amplitude of the orbit had also increased significantly, particularly in the y direction, where it increased by 88.6%. Subsequently, a combined approach of pump computational fluid dynamics (CFD) analysis and rotor finite element analysis was used to analyze the cause of the axis orbit change. The study revealed the existence of a vortex with a pulsating frequency of approximately 16.4 Hz at the inlet of the non-uniform inflow. This vortex caused the impeller's attack angle to deviate from the design value, resulting in flow separation inside the impeller, an increase in the impeller's radial force, and radial force pulsation at the same frequency as the vortex. The change in the axis orbit was caused by the superposition of the rotor's unbalance mass and radial force pulsation under non-uniform inflow. [ABSTRACT FROM AUTHOR]

• The quasi-unidirectional spatiotemporal self-mode locked is realized in an Er-doped fiber laser. • Different spatial dynamics of the STML solitons in the CW and CCW directions are observed. • The maximum output power in the CCW and CW directions can reach 61.56 mW and 63.84 mW, respectively. A spatiotemporal (ST) self-mode locked (ML) Er-doped fiber laser based on the nonlinear multimode interference (NL-MMI) effect without an intracavity isolator has been proposed. Such a STML laser could operate in a quasi-unidirectional regime in both clockwise (CW) and counter-clockwise (CCW) directions. Different spatial dynamics of the STML solitons in the opposite directions are observed. For the STML solitons in the CCW direction, the beam profile is discretely distributed and the transverse mode instability (TMI) is observed. While for the STML solitons in the CW direction, the beam profile is relatively concentrated and can be partially controlled by adjusting the intracavity multimode (MM) fiber at the front-end of the MM coupler. These investigations would help to gain further understanding of the spatial and temporal dynamics and mechanism in the STML lasers. [ABSTRACT FROM AUTHOR]

• The large energy polarization convertible solitons is realized in an all-PM mode-locked Yb-doped fiber laser. • Fiber laser can realize 90° polarization conversion from fast axis to slow axis by changing the pump power. • The maximum output power of the fiber laser system is 154.93 mW, corresponding to the pulse energy of 9.53 nJ. In this paper, we have demonstrated an all polarization maintaining (PM) composite ultrafast Yb-doped fiber laser system mode-locked by semiconductor saturable absorber mirror (SESAM), which incorporates the amplifier with the resonant cavity together. Benefiting from this composite laser system, not only the pulse energy is significantly improved, but also polarization convertible solitons are realized. When the pump power is lower than 272 mW, the solitons with the central wavelength of 1029.78 nm and the pulse width of 16.54 ps are transmitting along the fast axis. However, the polarization direction of solitons is switched to slow axis as increasing the pump power to be larger than 272 mW. The maximum output power of the solitons can reach 154.93 mW, corresponding to the pulse energy of 9.53 nJ. To the best of our knowledge, this is the first time to realize 90° polarization conversion for ultrafast solitons in an all-PM fiber laser system. We believe the presented approach reveals a pulse scaling and polarization convertible potential of mode-locked fiber laser. [ABSTRACT FROM AUTHOR]

Intelligent condition identification is the development trend of transformer condition recognition, However, the existing intelligent condition recognition has the disadvantage of single model and low recognition accuracy. In order to overcome the disadvantage, a transformer condition recognition method based on dissolved gas analysis features selection and multiple models fusion is proposed. At first, artificial bee colony (ABC) algorithm is employed to select a set of optimal dissolved gas analysis (DGA) features. Then, according to the selected feature set, support vector classifier (SVC) model, naive bayes classifier (NBC) model, and back-propagation neural network (BPNN) model are respectively established. Finally, the Dempster–Shafer​ (D-S) evidence theory is used to combine the output results of the three recognition models. The identification performances of the optimal DGA features set and the multiple models fusion are evaluated. The results reveal that the proposed method has the highest accuracy and consistency of 89.39% and 90.49% respectively. With the input vector of proposed optimal DGA features set, the overall performance of multiple model fusion method is superior than the SVC, NBC, BPNN, extreme learning machine (ELM) and K- Nearest-Neighbor (KNN). The accuracy and consistency are increased by 4.54%, 4.52%, and 10.42%, 14.68%, and 3.03%, 3.67%, and 10.6%, 13.45%, and 24.24%, 27.57% respectively. Also, the overall performance of multiple model fusion method with optimal DGA features set is increased significantly compared to multiple model fusion method with IEC Ratio, Rogers Ratio, Doernenburg Ratio, optimal DGA features set selected by particle swarm optimization (PSO) and harris hawks optimization (HHO). The accuracy and consistency are increased by 4.54%, 7.43%, and 6.06%, 7.33%, and 10.6%, 13.58%, and 1.51%, 1.39%, and 9.09%,10% respectively. This proves the effectiveness and the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) is frequently employed in biomedical engineering due to its biocompatibility. Traditionally, PEEK manufacturing methods involve injection molding, compression molding, additive manufacturing, or incremental sheet forming. Few studies have focused on rotational friction welding (RFW) with PEEK plastics. Based on years of RFW practical experience, the mechanical properties of the weldment are related to the burn-off length. However, few studies have focused on this issue. Therefore, the main objective of this study is to assess the effects of burn-off length on the mechanical properties of the welded parts using PEEK polymer rods. The welding pressure can be determined by the rotational speed according to the proposed prediction equation. The burn-off length of 1.6 mm seems to be an optimal burn-off length for RFW. For the rotational speed of 1000 rpm, the average bending strength of the welded parts was increased from 108 MPa to 160 Mpa, when the burn-off length was increased from 1 mm to 1.6 mm and the cycle time of RFW was reduced from 80 s to 76 s. A saving in the cycle time of RFW of about 5% can be obtained. The bending strength of the welded part using laser welding is lower than that using RFW, because only the peripheral material of the PEEK cylinder was melted by the laser. [ABSTRACT FROM AUTHOR]

Three-dimensional printing is widely used for manufacturing a variety of functional components. However, the 3D printing machine substantially limits the size of the functional components. Rotary friction welding (RFW) is a possible solution to this problem. In addition, there is a notable scarcity of research directed toward the domain knowledge of RFW involving dissimilar polymer rods containing metal powder. In this study, two welding specimens fabricated by polylactic acid (PLA)-containing copper powder and PLA-containing aluminum powder were joined using a turning machine. After RFW, a bending test and a Shore A surface hardness test were performed to investigate the weld quality. It was found that the bending strength of the welded parts fabricated by RFW of PLA and PLA-containing Al powder rods can be enhanced by about 57.5% when the welded part is placed at 45 °C. Surface hardness test results showed that the surface hardness of the weld interface is better than that of the 3D printed parts, and the average surface hardness of the weld interface from RFW of PLA and PLA is the highest. The surface hardness of the weld joint is about 3% higher than that of the base material. The surface hardness of the heat-affected zone is about 3% lower than that of the base material. The average peak temperature of the welded joint is the highest in the RFW of PLA-containing Al powder and PLA-containing Al powder rods. The average peak temperature of the weld joint can be as high as 160 °C. The average peak temperature of the welded joint is the highest in the RFW of PLA-containing Cu powder and PLA-containing Cu powder rods. The average peak temperature of the welded joint can be as high as 144 °C. A technical database was built for the selection of ambient temperatures used for the RFW of dissimilar polymer rods containing metal powder and three base materials. [ABSTRACT FROM AUTHOR]

The Gonghe Basin in the northeast Tibetan Plateau presents significant potential for hot dry rock (HDR) geothermal resources. A 1990 M w 6.4 earthquake in the basin furthers the need for an improved understanding of its sedimentary structure. In this study, we utilize data from a dense seismic array of 88 short-period seismometers deployed at an interstation spacing of approximately 3 km to scrutinize the sedimentary structure of the Gonghe Basin. By analysing teleseismic P waveforms, we identify P -to- S converted waves (Ps wave) originating from the sedimentary basement. We then determine the delay time between the Ps waves and the direct P waves (P wave) through waveform cross-correlation. By integrating this delay time with empirical velocity structure models, HDR borehole data and results from teleseismic receiver function analysis, we derive a sediment thickness model of the Gonghe Basin for the Qabqa geothermal area. Our findings reveal a gradual increase in sediment thickness from around 500 m in the east to approximately 3000 m in the west, which is consistent with other geophysical surveys and borehole data. The thick sediments in the basin could potentially serve as an excellent thermal storage cover for HDR. The strong ground motion simulation using our sediment thickness model shows that thick sediments can amplify seismic waves, increasing the risk of seismic hazards. Moreover, our study indicates that the clear Ps waves can be effectively extracted to construct a dependable sediment thickness model using teleseismic P waves recorded by a short-period dense seismic array. [ABSTRACT FROM AUTHOR]

Polyetheretherketone (PEEK) is a promising biomaterial due to its excellent mechanical properties. Most PPEK manufacturing methods include additive manufacturing, injection molding, grinding, pulse laser drilling, or incremental sheet forming. Rotary friction welding (RFW) is a promising bonding technique in many industries. However, very few studies have focused on the RFW of PEEK. Conventionally, the number of revolutions is fixed during the welding process. Remarkably, the rotary friction welding of PEEK polymer rods using an innovative variable rotational speed is investigated in this study. The average bending strength of the welded part using a three-stage transformation rotational speed was enhanced by about 140% compared with a rotational speed of 1000 rpm. The advantage of computer numerical controlled RFW of PEEK using variable rotational speed is a reduced cycle time of RFW. A reduction in cycle time of about 6% can be obtained using the proposed RFW with a three-stage transformation rotational speed. The innovative approach provides low environmental pollution and high energy efficiency and complies with sustainable development goals. [ABSTRACT FROM AUTHOR]

This study considers a retailer's optimal endogenous demand information acquisition format decision in a dual-channel supply chain setting. Two information acquisition formats are examined, depending on whether the outcome of information acquisition is observable to the manufacturer. We explicitly characterize the manufacturer's optimal contract provision under each acquisition format, and derive the retailer's optimal endogenous information acquisition format choice. Two underlying driving forces for the retailer's preference for the observable acquisition are derived. On one hand, observable acquisition makes the retailer lose some informational advantage, which is detrimental to the retailer. On the other hand, observable acquisition may alleviate the ordering quantity distortions, which is beneficial to the retailer. In equilibrium, we show that the retailer with an inferior acquisition capability might be pleased to choose observable acquisition when the market dispersion is in the middle range. Although the manufacturer consistently obtains more profit under observable acquisition, the supply chain may still prefer unobservable acquisition because the observability of information acquisition may aggravate double marginalization under certain conditions. Moreover, the introduction of the direct sales channel may dampen the retailer's incentive to choose the observable acquisition format. [ABSTRACT FROM AUTHOR]

To enhance the productivity and quality of optical-grade liquid silicone rubber (LSR) and an optical convex lens simultaneously, uniform vulcanization of the molding material is required. However, little has been reported on the uniform vulcanization of LSR in the heated cavity. This paper presents a conformal heating channel to enhance the temperature uniformity of the mold surface in the LSR injection molding. The curing rate of an optical convex lens was numerically investigated using Moldex3D molding simulation software. Two different sets of soft tooling inserts, injection mold inserts with conventional and conformal heating channels, were fabricated to validate the simulation results. The mold surface temperature uniformity was investigated by both numerical simulation and experiment. In particular, both a thermal camera and thermocouples were employed to measure the mold surface temperature after LSR injecting molding. It was found that the uniformity of the mold surface for LSR injection mold with the conformal heating channel was better. The average temperature of the mold surface could be predicted by the heating oil temperature according to the proposed prediction equation. The experimental results showed that the trend of the average temperature of five sensor modes was consistent with the simulation results. The error rate of the simulation results was about 8.31% based on the experimental result for the LSR injection mold with the conformal heating channel. [ABSTRACT FROM AUTHOR]

Rotary friction welding (RFW) has no electric arc and the energy consumption during welding can be reduced as compared with conventional arc welding since it is a solid-phase welding process. The RFW is a sustainable manufacturing process because it provides low environmental pollution and energy consumption. However, few works focus on the reliability of dissimilar polymer rods fabricated via RFW. The reliability of the frictionally welded components is also related to the ambient temperatures. This work aims to investigate the effects of ambient temperature on the mechanical properties of frictionally welded components of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) dissimilar polymer rods. It was found that the heat-affected zone width increases with increasing rotational speeds due to peak welding temperature. The Shore A surface hardness of ABS/PC weld joint does not change with the increased rotational speeds. The Shore A surface hardness in the weld joint of RFW of the ABS/PC is about Shore A 70. The bending strength was increased by about 53% when the welded parts were placed at 60–70 °C compared with bending strength at room temperature. The remarkable finding is that the bending fracture position of the weldment occurs on the ABS side. It should be pointed out that the bending strength can be determined by the placed ambient temperature according to the proposed prediction equation. The impact energy was decreased by about 33% when the welded parts were placed at 65–70 °C compared with the impact energy at room temperature. The impact energy (y) can be determined by the placed ambient temperature according to the proposed prediction equation. The peak temperature in the weld interface can be predicted by the rotational speed based on the proposed equation. [ABSTRACT FROM AUTHOR]

This study investigates the optimal contract design with countervailing incentives under asymmetric selling cost information in a dual-channel supply chain comprising a manufacturer and retailer. The manufacturer's selling cost is private and determines their reservation profit, which gives rise to type-dependent participation constraints. This study provides several intriguing results. First, when the external market correctly evaluates the selling cost advantage of the manufacturer, information asymmetry does not necessarily hamper channel efficiency, even in the dual-channel setting. Second, the retailer may distort the manufacturer's selling quantity either upward or downward, while the retailer may distort their own selling quantity in the opposite direction. Such a synergistic effect unique to the dual channels may help the retailer balance information rent extraction and channel efficiency. Third, the manufacturer may benefit from intensified channel competition as long as the cost differential is not significant, or the cost differential is significant, but the channel substitution rate is relatively low. Finally, further examining the value of information, we demonstrate that the profit differential of the retailer (manufacturer, supply chain) exhibits an inverted U-shaped (U-shaped, hat-shaped) pattern with respect to the low-cost manufacturer's reservation profit. • The optimal contract with countervailing incentives in dual channels is studied. • Information asymmetry does not necessarily undermine channel efficiency. • The supply chain members can benefit from the intensified channel competition. • The efficient manufacturer's proportion may benefit/hurt the firms and supply chain. [ABSTRACT FROM AUTHOR]

We studied the hydrogen storage properties of commercial AZ31 and AZ91 magnesium alloys with refined microstructure. Various processing techniques, such as equal channel angular pressing (ECAP) and high energy ball milling (HEBM), were utilized to modify the microstructure and phase composition of the alloys. X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical digital microscopy (ODM) were utilized to characterise the microstructure and phase transformations during the hydrogen absorption/desorption processes. The isothermal kinetics are measured by a Sieverts'-type apparatus at the temperature of 350 ℃. In the ECAP process, the AZ31 alloy had a slightly higher storage capacity and faster absorption kinetics, absorbing 6.0 wt% (6.6 wt% - maximum) of hydrogen in less than 12 min. In the HEBM process, AZ91 absorbed 6.5 wt% of hydrogen and desorbed it in 347 ± 13 s, a faster rate than AZ31. The pressure–composition isotherms of all studied alloys at a temperature of 300 °C were determined. The processed alloys exhibited no pressure hysteresis. The microstructure of bulk samples and the morphology of prepared powders were shown to affect their hydrogenation behaviour. The activation energies for hydrogen desorption were 119 ± 2 kJ/mol for AZ31 alloy processed by ECAP and 128 ± 3 kJ/mol for AZ91 alloy processed by HEBM, which are significantly lower than the activation energy values of pure Mg hydride. • Hydrogen storage properties of commercial AZ31 and AZ91 alloys are studied. • The ECAP and HEBM processes were employed to enhance hydrogen storage performance. • Both processes significantly improved the kinetic and thermodynamics properties. • The processed alloys exhibited no pressure hysteresis • The activation energies reduced to 119 ± 5 kJ/mol for AZ31-ECAP and 128 ± 5 kJ/mol for AZ91-HEBM. [ABSTRACT FROM AUTHOR]

• The bidirectional mode locking and the quasi-unidirectional mode locking is realized in an Er-doped fiber laser. • The bidirectional operations could show different soliton state of the forward conventional solitons and backward bound solitons. • A record pulse energy of 1.12 nJ at the pump power of 430 mW is achieved. In this paper, we have experimentally demonstrated an ultrafast Er-doped fiber laser mode-locked by the GIMF-based saturable absorber without an optical isolator for various soliton behaviors. The adjustment of the polarization controller results in different losses for the counter-propagating lasers. And thus, not only the bidirectional solitons, but also the quasi-unidirectional solitons are realized. For the bidirectional operation, the counterpropagating conventional solitons with the pulse energy of >1.12 nJ demonstrates different central wavelengths, repetition rates, and pulse widths. For the unidirectional operation, the laser operates in either the clockwise or the counter-clockwise directions with an emission strengths difference of larger than 31 dB. Interestingly, the bidirectional operations could show different soliton state of the forward conventional solitons and backward bound solitons. Our research would be beneficial for the further understanding of the formation and transformation of the bidirectional solitons and can find vital applications in gyroscopic and other dual-channel applications. [ABSTRACT FROM AUTHOR]