High-Precision Anti-Interference Control of Direct Drive Components

This study presents a compound control algorithm that enhances the servo accuracy and disturbance suppression capability of direct drive components (DDCs). The servo performance of DDCs is easily affected by external disturbance and the deterioration of assembly characteristics due to a lack of deceleration device. The purpose of this study is to compensate for the impact of external and internal disturbances on the system. First, a linear state space model of the system is established. Second, we analyzed the main factors restricting the performance of DDCs which includes sensor noise, friction and external disturbance. Then, a fractional-order proportional integral (FOPI) controller was used to eliminate the steady-state error caused by the time-invariable disturbance which can also improve the system’s anti-interference capability. A state-augmented Kalman filter (SAKF) was proposed to suppress the quantization noise and compensate for the time-varying disturbances simultaneously. The effectiveness of the proposed compound algorithm was demonstrated by comparative experiments, demonstrating a maximum 89.34% improvement. The experimental results show that, compared with the traditional PI controller, the FOPISAKF controller can not only improve the tracking accuracy of the system, but also enhance the disturbance suppression ability

Friction and Wear Properties of Si-containing H-free Amorphous Carbon-based Films

To investigate the effect of Si incorporation on friction and wear properties of H-free amorphous carbon-based films, Si-containing H-free amorphous carbon films were deposited on Si and 304 stainless steel substrates by direct current magnetron sputtering method. The composition, structure and mechanical properties of the films were examined by scanning electron microscopy (SEM), Raman spectra, nanoindenter and other techniques. The tribological properties of the films were tested in dry contact conditions using a reciprocating sliding tribometer with ball-on-disk contact geometry. The results indicate that Si incorporation reduces the residual stress of films and promotes the sp~3 hybridization. The film hardness is increased by Si incorporation over 10%. The addition of Si has little influence on friction coefficient of H-free carbon film under various wetting conditions. Si-doped films show higher wear rates than the H-free film, and their wear rates increase with increasing Si contents and decreasing relative humidity. High Si content within films causes significant instability of friction coefficient and leads to severe wear of the films in the low humid air. This suggests that the degradation in performance resulting from Si doping should be fully considered in designing and developing H-free amorphous carbon-based tribological coatings with excellent properties

Effect of anodic oxidation of 2024-T3 aluminum alloy on interface properties of metal fiber laminates

Interlaminar fracture failure is the main factor restricting the development and application of fiber metal laminates. In this paper, the interlayer bonding properties of 2024-T3 aluminum alloy plates with different surface treatments were compared and studied through lap-shear experiments. Compared with the aluminum plate treated with acid and alkali corrosion, the interlaminar shear strength of the aluminum plate after sulfuric acid anodization increased by 34.3%. After different surface treatments, experimental stressstrain curves of 2024-T3 aluminum alloys reveal the enhancement mechanism and changing trend of interlaminar shear strength

Theoretical and Experimental Investigation of Explosion Characteristics of Hydrogen Explosion in a Closed Vessel

A simplified model that calculates the deflagration pressure–time curves of a hydrogen explosion was proposed. The deflagration parameters (pressure peak, duration, deflagration index, and impulse) of hydrogen–air mixtures with different hydrogen concentrations were experimentally investigated. The results show that the pressure curves calculated by the model are consistent with experimental data pertaining to a methane and hydrogen explosion. By comparison, the pressure peak and deflagration index are found to be influenced by the aspect ratio and surface area of vessels. The impulse and explosion times at fuel-lean hydrogen concentrations are greater than those at fuel-rich concentrations. When the hydrogen concentration is between 34 vol.% and 18 vol.%, the greatest explosion damage effect is formed by both the overpressure and the impulse, which should be considered for hydrogen explosion safety design in industrial production

Theoretical and Experimental Investigation of Explosion Characteristics of Hydrogen Explosion in a Closed Vessel

A simplified model that calculates the deflagration pressure–time curves of a hydrogen explosion was proposed. The deflagration parameters (pressure peak, duration, deflagration index, and impulse) of hydrogen–air mixtures with different hydrogen concentrations were experimentally investigated. The results show that the pressure curves calculated by the model are consistent with experimental data pertaining to a methane and hydrogen explosion. By comparison, the pressure peak and deflagration index are found to be influenced by the aspect ratio and surface area of vessels. The impulse and explosion times at fuel-lean hydrogen concentrations are greater than those at fuel-rich concentrations. When the hydrogen concentration is between 34 vol.% and 18 vol.%, the greatest explosion damage effect is formed by both the overpressure and the impulse, which should be considered for hydrogen explosion safety design in industrial production

Memory-like NK cells armed with a neoepitope-specific CAR exhibit potent activity against NPM1 mutated acute myeloid leukemia

Acute myeloid leukemia (AML) remains a therapeutic challenge, and a paucity of tumor-specific targets has significantly hampered the development of effective immune-based therapies. Recent paradigm-changing studies have shown that natural killer (NK) cells exhibit innate memory upon brief activation with IL-12 and IL-18, leading to cytokine-induced memory-like (CIML) NK cell differentiation. CIML NK cells have enhanced antitumor activity and have shown promising results in early phase clinical trials in patients with relapsed/refractory AML. Here, we show that arming CIML NK cells with a neoepitope-specific chimeric antigen receptor (CAR) significantly enhances their antitumor responses to nucleophosphmin-1 (NPM1)-mutated AML while avoiding off-target toxicity. CIML NK cells differentiated from peripheral blood NK cells were efficiently transduced to express a TCR-like CAR that specifically recognizes a neoepitope derived from the cytosolic oncogenic NPM1-mutated protein presented by HLA-A2. These CAR CIML NK cells displayed enhanced activity against NPM1-mutated AML cell lines and patient-derived leukemic blast cells. CAR CIML NK cells persisted in vivo and significantly improved AML outcomes in xenograft models. Single-cell RNA sequencing and mass cytometry analyses identified up-regulation of cell proliferation, protein folding, immune responses, and major metabolic pathways in CAR-transduced CIML NK cells, resulting in tumor-specific, CAR-dependent activation and function in response to AML target cells. Thus, efficient arming of CIML NK cells with an NPM1-mutation-specific TCR-like CAR substantially improves their innate antitumor responses against an otherwise intracellular mutant protein. These preclinical findings justify evaluating this approach in clinical trials in HLA-A2 + AML patients with NPM1c mutations. </jats:p