Adjustable/controllable bearings are the future direction of journal bearings and are used to correct design blind spots and handle changing operating conditions. This study investigates a clearance-adjustable bearing structure and its adjustment method to improve the operating stability of a rotor system under different working conditions. The theoretical model of this adjustable journal bearing was constructed and its lubricating characteristics under different clearances are analyzed. The Reynolds equation and the rotor dynamics equation were coupled to calculate the oil film force of the adjustable bearing introduced into the rotor system. The effect of the adjustable bearings on the dynamic response of the rigid rotor was investigated under different speeds and loads. Further, the adjustment methods required to improve the operation of the rigid rotor system were identified. Consequently, a finite element model of the adjustable bearing-rotor system was established to study the effect of the adjustable bearing on the dynamic behavior of the slender rotor system. In addition, the vibration response of the slender rotor within different speed regions was analyzed and the reasons for the change in amplitude owing to bearing clearance adjustment were explained. Furthermore, the corresponding test bench was constructed for experimental verification, and the essence of the adjustable bearing changing the dynamic response of the rotor system was described.

Immune checkpoint blockade (ICB)-based immunotherapy is limited by its poor tumor targeting and rapid clearance of antibodies. Here, we developed the acoustic vortex (AV) tweezers that actively aggregated microbots for spatiotemporally controlled in situ explosive anti-PD-L1 production to achieve localized ICB-based immunotherapy. Engineered bacteria were conjugated with multifunctional nanoparticles combining chemotherapy, sonodynamic therapy, and plasmid-encoded anti-PD-L1, forming microbots capable of ultrasound-mediated aggregation and deep tumor penetration. AV tweezers with a larger annular focal region compared with conventional ultrasound, actively induced microbot aggregation in tumor-associated vasculature, while mild hyperthermia triggered expression and secretion of IFN-γ, promoting M2-to-M1 macrophage polarization. The release of DOX and Ce6 induced immunogenic cell death, synergistically enhancing anti-tumor responses. The localized antibody production factory achieved high intratumoral anti-PD-L1 level while limiting systemic exposure, thereby overcoming major limitations of conventional ICB therapy. Hence, this strategy established a programmable and dual-targeting platform for precise tumor immunotherapy.

Structures and energetics of grain boundaries (GBs) can significantly modulate various properties of polycrystals. Previous studies focus on the ground-state GB structures of β-SiC while the metastable states are poorly understood. Herein, atomistic simulations are employed to generate metastable structures for a series of ⟨001⟩ symmetric tilt GBs in β-SiC. Structural units (SUs) based on the edge dislocation core structures are defined to characterize the GB structures. All GB structures can be divided into four types according to their different constituent SUs. Various distributions, orderings and combinations of SUs can generate multiple metastable structures with different GB energies. Furthermore, our calculations of low-angle GB energies agree well with the theoretical predictions based on the continuum elasticity theory. Our findings not only enhance the fundamental understanding of the (meta)stable grain boundary energetics and structural characteristics but also have significant implications for micro-structure design and grain boundary engineering in polycrystalline SiC.

To promote the utilization of Mo2NiB2-Ni cermet under sulfuric acid drew corrosion conditions, it is essential to elucidate the resistance mechanism of these cermets to sulfuric acid corrosion. In this study, the corrosion behavior of Mo2NiB2-Ni cermets with different Ni content in 90 wt % H2SO4 solution at 110 degrees C was investigated, and the corrosion resistance mechanism was analyzed. The results reveal that the corrosion weight losses and corrosion rates of the cermets decreased with increasing Ni content. Mo2NiB2-Ni cermets with higher Ni contents exhibited improved corrosion resistance. This improvement can be attributed to the generation of a considerable amount of NiSO4 corrosion products from the Ni binder phase corroded by H2SO4, which led to the subsequent formation of a large-scale, flat, and dense corrosion products layer with a certain thickness. This effectively prevented further erosion of the inner matrix and improved the corrosion resistance of the cermet. Additionally, the electrochemical results indicate that the corrosion product layer hindered the passage of electric charges through the layer, which inhibited the corrosion reaction.

6-Methoxydihydrosanguinarine (6-MDS) is a natural benzophenanthridine alkaloid extracted from Hylomecon japonica (Thunb.) Prantl. It is the first time to explore the effect and mechanism of 6-MDS in breast cancer. Network pharmacology, molecular docking, and molecular dynamics simulation technology were adopted to identify the potential targets and pathways of 6-MDS in breast cancer. Besides, cell proliferation, apoptosis, and western blotting assays were conducted to investigate the effect of 6-MDS on MCF-7 cells. Network pharmacology, molecular docking, and molecular dynamics simulation results confirmed the effect of 6-MDS on resisting breast cancer via the PI3K/AKT/mTOR signaling pathway. In addition, the functional experiments results demonstrated that 6-MDS inhibited proliferation and induced apoptosis and autophagy. The autophagy inhibitor chloroquine and the silence of Atg5 augmented the effect of 6-MDS on promoting apoptosis. Furthermore, 6-MDS suppressed the PI3K/AKT/mTOR signaling pathway, and the PI3K inhibitor LY294002 enhanced these changes and promoted the 6-MDS pro-apoptotic and autophagy effects. 6-MDS triggered the generation of reactive oxygen species. The pretreatment with antioxidant N-acetyl-L-cysteine reversed the changes induced by 6-MDS, including increases in apoptosis and autophagy and inhibition of the PI3K/AKT/mTOR pathway. In conclusion, 6-MDS induces the apoptosis and autophagy of MCF-7 cells by ROS accumulation to suppress the PI3K/AKT/mTOR signaling pathway.

Sonodynamic therapy (SDT) not only has greater tissue-penetrating depth compared to photo-stimulated therapies, but also can also trigger rapid drug release to achieve synergistic sonochemotherapy. Here, reactive oxygen species (ROS)-responsive IR780/PTL- nanoparticles (NPs) are designed by self-assembly, which contain ROS-cleavable thioketal linkers (TL) to promote paclitaxel (PTX) release during SDT. Under ultrasound (US) stimulation, IR780/PTL-NPs produce high amounts of ROS, which not only induces apoptosis in human glioma (U87) cells but also boosts PTX released by decomposing the ROS-sensitive TL. In the U87 tumor-bearing mouse model, the IR780/PTL-NPs releases the drug at the target sites in a controlled manner upon US irradiation, which significantly inhibits tumor growth and induces apoptosis in the tumor tissues with no obvious toxicity. Taken together, the IR780/PTL-NPs are a novel platform for sonochemotherapy, and can control the spatio-temporal release of chemotherapeutic drugs during SDT.

Radial clearance critically affects journal bearing performance, specifically the lubrication performance. This study investigates the lubrication characteristics of a journal bearing with adjustable radial clearance and compares the dynamic behavior of the bearing under laminar and turbulent flow regimes. The adjustable bearing exhibits two states of oil film pressure at different radial clearances. When the radial clearance is reduced from 100%cr to 80%cr, the oil film pressure is present only on the lower bearing bush; after being reduced to 70%cr, the upper bearing bush achieves effective lubrication; and after reduction from 70%cr to 30%cr, the oil film pressure increases more than six-fold. The turbulent flow model of the clearance adjustable bearing is then established considering the lubricant flow state, and the turbulence correction factors for different flow states are calculated. The journal bearing exhibits better lubrication characteristics under laminar than under turbulent flow conditions, and in some operating conditions, the stable velocity range calculated according to laminar flow theory may become unstable in turbulent flow conditions. Therefore, applying turbulence assumptions to design the operating speed range of rotating machinery under such conditions yields a greater safety threshold, which can reduce the risk of instability. The stability of the rotor bearing system is closely related to the radial clearance, and reducing the radial clearance will improve the stability of the system. In the turbulent flow state, the oil film pressure changes drastically, thus reducing the system stability. Moreover, the larger the radial clearance of the bearing, the more prominent the turbulence effect. Thus, reducing the bearing clearance prevents drastic changes in oil film pressure and improves the stability of the system.

This paper considered a nonlocally perturbed infinite sound hard surface scattering problem with tapered wave incidence by integral equation methods. We proposed a boundary integral equation for this scattering problem and proved the validity of the integral equation formulation. One of the most important tasks for actual calculations is to solve a truncation problem of unbounded surfaces. The existence and uniqueness of the solution for the finite truncated problem are obtained by analyzing the properties of truncation operators. These results are essential in the numerical solution of the scattering problems.

To promote the utilization of Mo2NiB2–Ni cermet under sulfuric acid drew corrosion conditions, it is essential to elucidate the resistance mechanism of these cermets to sulfuric acid corrosion. In this study, the corrosion behavior of Mo2NiB2–Ni cermets with different Ni content in 90 wt % H2SO4 solution at 110 °C was investigated, and the corrosion resistance mechanism was analyzed. The results reveal that the corrosion weight losses and corrosion rates of the cermets decreased with increasing Ni content. Mo2NiB2–Ni cermets with higher Ni contents exhibited improved corrosion resistance. This improvement can be attributed to the generation of a considerable amount of NiSO4 corrosion products from the Ni binder phase corroded by H2SO4, which led to the subsequent formation of a large-scale, flat, and dense corrosion products layer with a certain thickness. This effectively prevented further erosion of the inner matrix and improved the corrosion resistance of the cermet. Additionally, the electrochemical results indicate that the corrosion product layer hindered the passage of electric charges through the layer, which inhibited the corrosion reaction.

Focused ultrasound ablation provides a truly noninvasive tumor treatment option with clinically proven feasibility and safety. However, the frequently required long treatment duration hinders its clinical applicability. In this work, we compared the thermal ablation induced by conventional focused ultrasound (cFUS), split-focus ultrasound (sFUS), and acoustic vortex (AV) in tissue phantoms containing phase-change nanodroplets and mouse tumors. The results indicated that AV could substantially enhance the thermal ablation efficiency compared with cFUS, which was attributed to the larger focal region in the former. Additionally, the ablation region appeared as a unique cylindrical area with a smaller length-to-width ratio in AV than that in cFUS. Though the efficiency could also be improved in sFUS compared with cFUS, the ablation region was irregular and non-ablated tissues were present. Furthermore, in vivo experiments demonstrated that the tumor volume decreased faster and the mice survived longer after AV treatment compared with cFUS. The cavitation activity was also found to be more intense in AV ablation. The proposed method may solve the general issue of low efficiency often observed in cFUS ablation and further promote the development of other ultrasound treatments.

In the present study, BaTi0.8-xZr0.2MnxO3 (x = 0, 0.25 %, 0.5 %, 0.75 %) ceramics were prepared via a solid-state reaction process. Results showed that both enhanced tunability of 93.4 % (at 20 kV/cm and 27 degrees C) and reduced dielectric loss tangent of 0.005 at 10 kHz were achieved in BaTi0.8-xZr0.2MnxO3 ceramics at x = 0.5 %. Such dielectric tunability was higher than that of common materials whose tunability hardly exceeded 85 %. Moreover, the mechanism of enhanced dielectric tunability was discussed. The contribution of the intrinsic polarization to the dielectric tunability increased with the increase of Mn content, leading to a higher tunability. Meanwhile, the "domain pinning" effect of (MnTi VO ) defect dipoles restricted the reor-x ientation of microdomains, thus decreasing extrinsic contribution and dielectric loss tangent. Furthermore, the tunability for the BaTi0.8-xZr0.2MnxO3 (x = 0 %, 0.25 %, 0.5 %, 0.75 %) samples was measured in the temperature range of - 30 to 85 degrees C, showing a favorable dielectric tunable performance with good tem-perature stability.(c) 2022 Published by Elsevier B.V.

Herein, the influence of the impact angle and Ni content on the wear behavior of Mo2NiB2–Ni cermets was studied using an erodent-carrying slurry comprising artificial seawater and SiO2 sands. The results reveal that the material loss may be attributed to the wear damage caused by SiO2 sands because cermets are expected to exhibit good corrosion resistance in artificial seawater. The relative density of cermets markedly influences their resistance to wear damage, and the material loss experienced by cermets with poor relative density is 2–4 times higher than that of cermets with good relative density; this occurs because a higher relative density can markedly enhance the mechanical properties and reduce the defects in the cermets. Moreover, the results indicate that as the impact angle increases from 0° to 60°, the manifestation of the wear mechanism changes from damaging the Ni binder phase (caused by single cutting wear) to damaging both the Mo2NiB2 ceramic and Ni binder phases due to the combination of cutting wear and impact wear. The wear damage is dominated by the cutting wear and impact wear from SiO2 sand at the low and high impact angles, respectively. Furthermore, the severe deterioration of the single ceramic skeleton at high impact angles indicates that the synergistic influence of the Mo2NiB2 ceramic and Ni binder phases on enhancing the wear resistance of the cermets intensifies at high impact angles.

High-intensity focused ultrasound (HIFU) thrombolysis provides a targeted and non-invasive therapy for thrombosis-related diseases. Rapid thrombolysis and restoration of blood flow are vital to reduce the disability and death rate. The objective of this study was to explore the feasibility of using a high-intensity focused acoustic vortex (HIFAV) to enhance sonothrombolysis. The in vitro clots were treated with HIFU with a peak negative pressure (PNP) of 2.86 MPa (HIFU A) or 3.27 MPa (HIFU B) or HIFAV with a PNP of 2.14 MPa. The results revealed that HIFAV thrombolysis could achieve a significantly higher efficiency than HIFU (HIFAV: 65.4%, HIFU A: 24.1%, HIFU B: 31.6%, p < 0.01), even at a lower intensity. The average size of the debris particles generated in HIFAV thrombolysis was similar to that in HIFU. Additionally, the cavitation activities were found to be more intense in HIFAV thrombolysis. Although the efficiency of HIFAV thrombolysis was higher when the pulse repetition frequency increased from 100 to 500 Hz (41.4% vs. 65.4%, p < 0.05), it decreased when the PRF reached 1000 Hz (29.9%). Lastly, it was found that increasing the duty cycle from 5% to 15% led to a higher efficiency in HIFAV thrombolysis (40.3% vs. 75.2%, p < 0.001). This study illustrated that HIFAV provided enhanced thrombolysis and that its efficiency could be further increased by optimizing the ultrasound parameters.

Four pairs of undescribed enantiomeric isoquinoline alkaloids (6S/R-(N,N-diethylacetamido)yl-dihydrochelerythrine, 6R/S-acetonyl-9-hydroxy-dihydrochelerythrine, 6S/R-acroleinyl-dihydrochelerythrine, 6S/R-acetatemethyl-dihydrochelerythrine), five undescribed isoquinoline alkaloids (6,10-dimethoxydihydrochelerythrine, 6-ethoxy-ethaniminyl-dihydrochelandine, 9-hydroxy-dihydrochelerythrine, 9-methoxy-10-hydroxy-norchelerythrine, chelidoniumine A), together with 13 known isoquinoline alkaloids were isolated from an extract of the roots and rhizomes of Hylomecon japonica. The structures of the undescribed compounds were identified by NMR, HRESIMS, UV, IR, and their absolute configurations were defined via electronic circular dichroism data and optical rotation. All of the isolated compounds were tested for their anti-breast cancer activities in MCF-7 cells. Among them, the undescribed alkaloids 6S/R-acroleinyl-dihydrochelerythrine, 6,10-dimethoxydihydrochelerythrine, 6-ethoxy-ethaniminyl-dihydrochelandine, 9-methoxy-10-hydroxy-norchelerythrine and other known alkaloids 6-methoxydihydrosanguinarine, 6-acetaldehyde-dihyrochelerythrine, dihydrosanguinaline and 10-methoxy boconoline had good inhibitory effects on MCF-7 cells of breast cancer with an IC50 lower than 20 μM.

An adjustable journal bearing is proposed to eliminate the influence of external operating parameters (such as speed) by actively adjusting the radial clearance. The paper introduces the structural design of the radial adjustable bearing and realizes the adjustment of the radial clearance through the mechanical transmission mechanism. Then, it introduces the working principle of adjusting bearing radial clearance. Finally, a method of adjusting the radial clearance is developed by studying the influence of the radial clearance on the vibration characteristics of the system. The bearing radial clearance has a great influence on the dynamic characteristics of the system. The essence of adjusting the radial clearance is to change the stiffness and damping coefficient of the oil film. In order to study the influence of radial clearance change on system stability, a two-degree-of-freedom adjustable bearing model was established. When the bearing system is running at low speed, properly reducing the radial clearance can improve the stability of the system. When the speed increases and the instability occurs, the radial clearance can be increased through the optimization adjustment method to restore the bearing from the high-speed instability state to the stable state. According to the research results, the optimal adjustment method of bearing clearance is determined. Finally, a test bench is built to verify that adjusting the radial clearance of the bearing can restore the stability of the system.

In the present study, BaTi(1-x)MxO3 (x = 0.005, 0.01, 0.015; M is Mn, Fe, and Co) ceramics were prepared by the conventional solid-state reaction method. Four distinct and independently addressed memory states were experimentally obtained based on the double hysteresis loop, which was achieved by acceptor doping in BaTiO3 ceramics. Moreover, this study indicated that for acceptor-doped BaTiO3 ceramics, larger electronegativity and smaller ionic radius of acceptor ions benefitted the more significant memory effect and better fatigue resistance. All these results could provide a promising solution for multi-state memory applications. (c) 2022 Published by Elsevier B.V.

Ferroptosis is an emerging form of programmed cell death, and its combination with sonodynamic therapy (SDT) for anti-tumor activity is gradually attracting attention. However, their application against gliomas has not been studied. Herein, multifunctional cancer homologous targeting biomimetic nanoparticles (PIOC@CM NPs) encapsulating both Fe3O4 and Ce6 were constructed as a nanosonosensitizer. Based on focused ultrasound (US) combined with circulating microbubbles (MBs) to open the blood-brain barrier (BBB) in a safe and transient manner, the development of a therapeutic strategy to integrate the biomimetic nanosonosensitizer-mediated SDT and ferroptosis could achieve synergistic therapeutic effects against gliomas. We demonstrated that the glioma C6 cell membrane (CM) on the surface of the NPs allowed the nanosonosensitizer to accumulate selectively in tumors through homologous targeting in vitro. After efficient internalization in C6 cells, the PIOC@CM NPs could significantly increase the level of reactive oxygen species (ROS) and deplete glutathione (GSH) upon ultrasonic irradiation, resulting in the loss of glutathione peroxidase-4 (GPX4) activity, which facilitated SDT and ferroptosis to kill glioma C6 cells. Furthermore, the PIOC@CM NPs were intravenously injected after noninvasively opening the BBB via US-MBs, which enhanced the accumulation of the nanosonosensitizer in tumor tissues. Crucially, an attractive phenomenon of the significant reduction in orthotopic gliomas after the second US pulse-triggered SDT and ferroptosis was observed. Taken together, this study presents a novel combinatorial glioma therapeutic strategy based on noninvasive BBB opening with a biomimetic sonotheranostic system-mediated SDT and ferroptosis.

In the present study, simultaneously enhanced electrical stability (low degradation rate of 8.0 x 10(-3) mA.h(1/2)) and high nonlinear coefficient of 56 were obtained in ZnO varistors by doping SiO2. To clarify the mechanism of enhanced properties, comprehensive microscopic analyses were studied. Particularly, the intrinsic point defects were quantitatively characterized for the first time. Results showed that the densities of zinc interstitials (Zni) and oxygen vacancies (Vo) were dramatically decreased, resulting in enhanced stability. Besides, reduced Zni and Vo decreased the total donor density, contributing to the improved barrier height and thus leading to enhanced nonlinearity. Combined with XRD and SEM results, it is deduced that such reduced Zni and Vo are attributed to the Si-stabilized high oxygen conducting delta-Bi2O3 phase. Furthermore, this elucidated mechanism, which has been long neglected in Si-doped varistors, may provide valuable insights into further developing high-performance ZnO varistors.

氧化锌电阻片在脉冲大电流作用下可能失效,威胁着电力设备及电力系统安全稳定运行.脉冲大电流作用下,电阻片瓷体的失效形式主要源自于瓷体本身的穿孔和炸裂.显微形貌观测结果表明,穿孔通道处有显著的晶粒熔融痕迹和微裂纹,这说明穿孔通道起源于电阻片电流、焦耳热局部集中,导致瓷体熔融和炸裂.基于未破坏区域和穿孔通道区域的微观分析,首次定义了晶粒尺寸分布的不均匀系数,统计分析了气孔及晶粒尺寸分布.计算结果表明,氧化锌电阻片穿孔通道附近气孔含量较多,且晶粒分布更加不均匀.大量的气孔和不均匀的晶粒尺寸分布使氧化锌电阻片形成显著的电气弱点,大电流作用下电流和由电流产生的焦耳热在此聚集.一方面,局部温度迅速升高,导致瓷体熔融;另一方面,当由温度梯度形成的机械应力大于瓷体的机械强度时,瓷体产生微裂纹.当微裂纹发展贯通之后,瓷体发生炸裂.

Targeted delivery of drug-loaded nanoparticles to brain tumors is exceptionally difficult due to the blood-brain barrier (BBB). In addition, several chemotherapeutic drugs induce autophagy, which protects the cells from apoptosis and mitigates the therapeutic effect. A novel "all-in-one" nanoparticles (AMPTL) consisting of endogenous reactive oxygen species-cleavable thioketal linkers conjugated to paclitaxel (PTX) and autophagy inhibitor 3-methyladenine, and angiopep-2 peptide-modified DSPE-PEG(2K) is developed. AMPTL inhibits autophagy in the C6 glioma cells, as indicated by fewer autophagic vesicles, lower LC3-II expression and accumulation of SQSTM1/P62, and significantly upregulates p53 and the pro-apoptotic Bax and cleaved caspase-3 proteins. In addition, AMPTL treatment induces cell cycle arrest at the G2/M phase. Thus, inhibition of autophagy in the AMPTL-treated glioma cells sensitizes them to PTX-induced cell cycle arrest and apoptosis. Furthermore, focused pulse ultrasound and microbubbles enhances the delivery of AMPTL to intracranial glioma tissues by reversibly opening the BBB, which significantly inhibits xenograft growth and markedly improves survival rates of the tumor-bearing mice. Taken together, combining non-invasive BBB opening with autophagy inhibitors and chemotherapeutic drugs can achieve cascade-amplifying synergistic therapeutic effects against glioma.