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Abstract Background It is challenging to improve the effects of chemotherapy and reduce its adverse impact on the ovaries. Our previous study suggested that the combination of galaxamide could enhance the antitumor effect of cisplatin (CIS) in HeLa cell xenograft mice. However, their potential effects on ovarian tissues remain unknown. Methods The Hela tumor-bearing female BALB/c mice model was established and randomly divided into three groups: control group (PBS group), CIS group (0.3 mg/kg CIS group) and galaxamide group (0.3 mg/kg CIS + 3 mg/kg galaxamide-treated group). The serum sex hormones levels, ovarian morphology, functional and molecular characterisation were determined and compared with those of the control group. Results The hormonal effects indicated premature ovarian insufficiency (POI) associated with CIS-induced tumor-bearing mice. CIS induces the apoptosis in primordial and developing follicles and subsequently increases follicular atresia, eventually leading to follicle loss. After cotreatment, galaxamide significantly increased anti-Mullerian hormone (AMH) and follicle-stimulating hormone receptor (FSHR) expression and prevented the CIS-induced PI3K pathway, which triggers follicle activation, apoptosis or atresia. Conclusion These findings demonstrate that galaxamide could attenuate CIS-induced follicle loss by acting on the PI3K signaling pathway by stimulating AMH and/or FSHR and thus provides promising therapeutic options for patients with cervical cancer.

The fluid–structure interaction effect should not be disregarded when examining the vibration characteristics of hydraulic pipeline systems. The transfer matrix method (TMM) is an efficacious method for analyzing the vibration characteristics of hydraulic pipelines in the frequency domain, offering advantages such as simplicity and efficiency. However, the TMM suffers the problem of high frequency instability when dealing with long-span hydraulic pipelines, which restricts its practical application. Currently, several modified transfer matrix methods face challenges such as low computational efficiency and difficulties in handling complex boundaries. In response to these issues, this paper proposes a novel modified transfer matrix method known as the mixed variable transfer matrix method. This innovative method possesses clear physical significance and effectively prevents the transfer matrix from becoming singular without necessitating the subdivision of the pipeline length. Consequently, it addresses high-frequency instability while maintaining high computational efficiency. Moreover, this method is capable of addressing complex boundary problems by integrating boundary matrices, thereby demonstrating enhanced applicability compared to existing methods. The performance of the proposed method was validated through the utilization of classic Dubee pipeline impact test data, and the result shows maximum errors of 3.03% relative to the public data. Subsequently, an experiment was conducted on a section of hydraulic piping within a ship’s steering system. A hydraulic fluid noise generator was established to induce fluid pulsation excitation to the pipeline, thereby simulating the actual boundary conditions encountered in a ship’s hydraulic pipeline system so as to corroborate the efficacy of the proposed method in predicting the frequency domain vibration characteristics of a real hydraulic pipeline system. The experimental results indicate that the proposed method offers significant advantages in terms of high precision, efficiency, and stability, shows maximum errors of 4.35% relative to experimental data, and demonstrates promising prospects for engineering applications.

The symmetrical oil suction and discharge chambers and the reversing rotation condition of bidirectional involute internal gear pumps result in low oil absorption capacity and flow pulsation due to cavitation. However, efforts to address these issues suffer from an incomplete understanding of the effects of oil properties, suction chamber volume, suction pressure, and rotational speed on the oil absorption capacity and cavitation characteristics of these pumps. The present work addresses this issue by conducting detailed computational fluid dynamics (CFD) simulations. The results of analysis demonstrate that the degree of cavitation caused by changes in the mass fraction of dissolved gas in the oil is positively correlated with flow pulsation, while the degree of cavitation caused by changes in the suction port size, suction pressure, and rotational speed is negatively correlated with flow pulsation. The degree of cavitation in the oil suction cavity initially increases as the mass fraction of dissolved gas in the oil increases, and then decreases. The rotational speed exhibits a critical value, where the oil absorption capacity increases with increasing rotational speed below the critical value, and decreases with increasing rotational speed above the critical value. The results of this research are expected to be of great significance for guiding improvements in the design of bidirectional involute internal gear pumps and the determination of critical working conditions.

The steering system noise is one of the main noise sources in submarine stealth condition. Combined with the composition of the steering system, the noise source of each component is sorted out systematically, and corresponding vibration and noise reduction design measures are proposed. As the main noise source of the steering system, emphasis is placed on analyzing the noise mechanism of the rudder hydraulic system, which is divided into two categories and six types according to steady state and transient operating conditions. Finally, it is pointed out that the new type electro-hydraulic steering gear, based on direct drive servo control principle, is the future development trend.

Abstract Compared with involute internal gear pumps and gerotor pumps, lower flow ripple is the main advantage of Truninger pumps. Understanding the flow ripple mechanism and characteristics is of great significance to guide the design and manufacture of this type of pump. In this paper, the theoretical flow ripple and flow ripple rate expressions of the pump are derived based on the vector ray method, and the effects of variations of the design parameters of the pump on the theoretical flow ripple characteristics are studied. A three-dimensional numerical simulation model was established in Simerics-MP+ that accounted for the fluid properties and cavitation. All the geometric features, including unloading grooves, the oil distribution areas, the shapes of the suction and delivery passageways, and the axial and radial leakage gaps, were considered to achieve the highest accuracy in the prediction of flow ripple. Finally, a flow ripple test platform was built based on the secondary source method. The validity and accuracy of the model were verified by test results. The flow ripple characteristics under different working conditions were compared and analyzed. The following conclusions were obtained: (1) The smaller module, the larger addendum coefficient and the half angle of the tooth profile in the design process, the lower the pump speed during operation is beneficial to reduce the vibration and noise of this pump; (2) Flow ripple is the comprehensive result of the oil characteristics, internal leakage, and geometric characteristics through the comparisons of theoretical, simulation and experimental results; (3) The flow ripple amplitude and the ripple rate increased with the increase in the outlet pressure and the influence of the pump speed variations on the flow ripple characteristics is less than that of outlet pressure variations. The conclusions obtained in this paper will help designers understand the flow ripple mechanism, achieve low-noise pump designs, and optimize Truninger pumps.

ObjectivesThe new type of electro-hydraulic steering gear with direct drive volume control is a typical system with large inertia and small damping. To solve the problem of control rapidity, stability and quietness contradicting each other, the engineering application of active disturbance rejection control (ADRC) for the electro-hydraulic steering gear is studied. MethodsFirst, the ADRC model of the electro-hydraulic steering gear is established and a transition process is designed to control the start-stop hydraulic impact. Next, a physical control test-bed is built, the stability of physical control is analyzed, the filtering effect of the algorithm is adjusted, an output filtering prediction module is added, and the big time delay of the electro-hydraulic steering gear is predicted and compensated. Finally, a comparative test of the algorithm control performance before and after optimization is carried out. ResultsThe experimental results show that, under the action of the improved ADRC control algorithm, the structural vibration of the electro-hydraulic steering gear in the start-stop transient state is reduced by about 6–10 dB, the position accuracy can be controlled within 1 mm, and the steering gear has good stability and followability under external interference such as load impact. ConclusionThe results of this study can provide references for the stability control and ADRC algorithms of systems with large inertia and small damping.

In order to solve the problem that the design constraints of the conjugated straight-line internal gear pair are unclear, the designing and checking of gear pairs requires repeated trial and error. By analogy with the design of the involute gear pair, the basic design parameters of the conjugated straight-line internal gear pair were clarified. Based on the mathematical model of the gear pair, the constraints on basic design parameters were given according to gear engagement theory and the geometrical relations of the tooth profile. The calculation formula and the constraint of the contact ratio were deduced according to the kinematic relations. Based on Litvin’s undercutting theory, the constraints on avoiding undercutting and end cutting were deduced and their correctness was verified by examples. The judgment method of tooth-overlapping interference and its corresponding numerical calculation flow were presented. The constraint on avoiding radial interference was deduced and analyzed. Based on the above content, the influence laws of design parameters on the design constraints were studied. Last, design examples were given and the effective design flow diagram of the conjugated straight-line internal gear pair was summarized. These research results provide a theoretical basis for the parameter design of conjugated straight-line internal gear pairs, provide guidance to avoid the interference of the gear pair, and promote the design system of the gear pair.

The raw signals produced by internal gear pumps are susceptible to noises brought on by mechanical vibrations and the surrounding environment, and the sample count collected during the various operating periods is not distributed evenly. Accurately diagnosing faults in internal gear pumps is significantly complicated by these factors. In light of these issues, accelerated life testing was performed in order to collect signals from an internal gear pump during various operating periods. Based on the architecture of a convolutional auto-encoder network, preprocessing of the signals in the various operating periods was performed to suppress noise and enhance operating period-representing features. Thereafter, variational mode decomposition was utilized to decompose the preprocessed signal into multiple intrinsic mode functions, and the multi-scale permutation entropy value was extracted for each intrinsic mode function to form a feature set. The feature set was subsequently divided into a training set and a test set, with the training set being trained to utilize a particle swarm optimization–least squares support vector machine network. For pattern recognition, the test set samples were fed into the trained model. The results demonstrated a 99.2% diagnostic accuracy. Compared to other methods of fault diagnosis, the proposed method is more effective and accurate.

The site-preference rule (SPR), which is widely used to design and study the properties of full-Heusler alloys X2YZ, is applied to determine the positions of different transition-metal elements with various numbers of valence electrons in Heusler alloys. The scandium-based full Heusler alloys should form an XA structure according to the SPR, because the transition-metal element Sc with fewer valence electrons tends to occupy the Wyckoff sites A(0, 0, 0) and B(0.25, 0.25, 0.25). As opposed to previous investigations, L21-type scandium-based full Heusler alloys, which do not follow the SPR, are also considered in this work. Theoretical computations are used to study the atomic-site preferences of 171 scandium-based full Heusler alloys, and the results indicate that most of these alloys form L21-type structures rather than XA-type structures. Two possible orderings are also studied in terms of their difference in charge density. Furthermore, the ground state, electronic structure, and magnetic characteristics of these alloys are also investigated in detail in both XA and L21 structures. The results reveal dramatic differences between XA- and L21-type alloys. This study thus presents a counterexample of the SPR rule and should provide significant guidance for the future design of full-Heusler alloys. Keywords: Full-Heusler alloys, Atomic orderings competition, First-principles, Spintronic

Mechanical equipment failure may cause massive economic and even life loss. Therefore, the diagnosis of the failures of machine parts in time is crucial. The rolling bearings are one of the most valuable parts, which have attracted the focus of fault diagnosis. Many successful rolling bearing fault diagnoses have been made based on machine learning and deep learning. However, most diagnosis methods still rely on complex signal processing and artificial features, bringing many costs to the deployment and migration of diagnostic models. This paper proposes an end-to-end continuous/discontinuous feature fusion method for rolling bearing fault diagnosis (C/D-FUSA). This method comprises long short-term memory (LSTM), convolutional neural networks (CNN) and attention mechanism, which automatically extracts the continuous and discontinuous features from vibration signals for fault diagnosis. We also propose a contextual-dependent attention module for the LSTM layers. We compare the method with the other simpler deep learning methods and state-of-the-art methods in rolling bearing fault data sets with different sample rates. The results show that our method is more accurate than the other methods with real-time inference. It is also easy to be deployed and trained in a new environment.

Spin-gapless semiconductors (SGSs) with Dirac-like band crossings may exhibit massless fermions and dissipationless transport properties. In this study, by applying the density functional theory, novel multiple linear-type spin-gapless semiconducting band structures were found in a synthesized R 3 − c -type bulk PdF3 compound, which has potential applications in ultra-fast and ultra-low power spintronic devices. The effects of spin-orbit coupling and on-site Coulomb interaction were determined for the bulk material in this study. To explore the potential applications in spintronic devices, we also performed first-principles combined with the non-equilibrium Green’s function for the PdF3/Ga2O3/PdF3 magnetic tunnel junction (MTJ). The results suggested that this MTJ exhibits perfect spin filtering and high tunnel magnetoresistance (~5.04 × 107).

A hypothetical full-Heusler alloy, Sc2VGe, was analyzed, and the comparison between the XA and L21 structures of this alloy was studied based on first-principles calculations. We found that the L21-type structure was more stable than the XA one. Further, the electronic structures of both types of structure were also investigated based on the calculated band structures. Results show that the physical nature of L21-type Sc2VGe is metallic; however, XA-type Sc2VGe is a half-metal (HM) with 100% spin polarization. When XA-type Sc2VGe is at its equilibrium lattice parameter, its total magnetic moment is 3 μ B , and its total magnetism is mainly attributed to the V atom. The effects of uniform strain and tetragonal lattice distortion on the electronic structures and half-metallic states of XA-type Sc2VGe were also studied. All the aforementioned results indicate that XA-type Sc2VGe would be an ideal candidate for spintronics studies, such as spin generation and injection.

Recently, an increasing number of rare-earth-based equiatomic quaternary compounds have been reported as promising novel spintronic materials. The rare-earth-based equiatomic quaternary compounds can be magnetic semiconductors (MSs), spin-gapless semiconductors (SGSs), and half-metals (HMs). Using first-principle calculations, we investigated the crystal structure, density of states, band structure, and magnetic properties of a new rare-earth-based equiatomic quaternary Heusler (EQH) compound, ScFeRhP. The results demonstrated that ScFeRhP is a HM at its equilibrium lattice constant, with a total magnetic moment per unit cell of 1 μB. Furthermore, upon introduction of a uniform strain, the physical state of this compound changes with the following transitions: non-magnetic-semiconductor-(NMS) → MS → SGS → HM → metal. We believe that these results will inspire further studies on other rare-earth-based EQH compounds for spintronic applications.