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Novel view synthesis using implicit neural functions such as Neural Radiance Field (NeRF) has achieved significant progress recently. However, it is very computationally expensive to train a NeRF due to the disordered frequency optimization. In this paper, we propose the Pyramid NeRF, which guides the NeRF training in a 'low-frequency first, high-frequency second' style using the image pyramids and could improve the training and inference speed at 15 × and 805 × , respectively. The high training efficiency is guaranteed by (i) organized frequency-guided optimization could improve the convergency speed and efficiently reduce the training iterations and (ii) progressive subdivision, which replaces a single large multi-layer perceptron (MLP) with thousands of tiny MLPs, could significantly decrease the execution time of running MLPs. Experiments on various synthetic and real scenes verify the high efficiency of the Pyramid NeRF. Meanwhile, the structure and perceptual similarities could be better recovered. [ABSTRACT FROM AUTHOR]

Collision on reinforced concrete (RC) piers by moving vessels or vehicles is a significant issue. This paper presents the static and impact behavior of RC piers with different hollow ratios. Three specimens were statically tested to obtain the load-displacement response. Low-velocity collision on eleven RC piers was conducted under the same velocity of 2.42 m/s. The damage process, failure mode, and force response were comprehensively analyzed. The experimental results indicate that the hollow ratio plays a significant role in the failure mode and ultimate load of RC piers under static and impact loadings. For RC piers with a hollow ratio of 0 and 0.4, the global failure dominated the damage process. However, failure of piers with a hollow ratio of 0.6 was governed by the local damage near the loading point. The static load capacities of the RC piers with a hollow ratio of 0.4 and 0.6 were 1.27% and 60.5% smaller than that of the solid pier, respectively. RC piers with a higher hollow ratio or lighter drop weight suffer smaller peak impact force. The increase of the longitudinal reinforcements leads to a promotion of the peak and mean impact force. Furthermore, the numerically predicted failure modes and impact load response show satisfactory agreement with the experimental results. [ABSTRACT FROM AUTHOR]

A combination of experimental and numerical studies was carried out to understand the microstructure and formation mechanism of kink bands in α / β two-phase titanium alloys. A deformation kink band was introduced in a Ti-9Cr alloy after uniaxial compression test. The strength changes of the α and β phases inside and outside the kink band were evaluated by nanoindentation tests. A potential hardening effect was revealed in the α phase inside the kink band, while a possible softening effect was located in the β phase at the kink boundaries. Microstructural examination of the kink band was conducted by electron backscatter diffraction measurement. The crystal rotation axis was found to be perpendicular to both the (0001) basal plane of the α phase and one of the (110) planes of the β phase. The crystallographic features were characterized by transmission electron microscopy observation, revealing a prismatic 〈 a 〉 slip that occurred during the compression to accommodate the rotations around the c-axis. Nanoindentation tests were performed on an undeformed specimen to calibrate the crystal plasticity model. A crystal plasticity finite element model was developed and {110} β -rotation-type kink bands were reproduced in the simulation and confirmed the prismatic slip activity. • During the uniaxial compression test, kink deformation was revealed in the α/β titanium two-phase alloy Ti-9Cr. • EBSD measurements, nanoindentation tests, and TEM observations were carried out on the deformed grain. • The rotation axis was found normal to the (0001) basal plane and one of the common (110) β planes. • The kink deformation was initiated by an intragranular crystal rotation accommodated by prismatic dislocations. • In the CPFEM simulation, the deformation kink bands were reproduced and confirmed the prismatic slip activity. [ABSTRACT FROM AUTHOR]

Efficient data dissemination in vehicular ad hoc networks (VANETs) is a challenging issue due to the dynamic nature of the network. To improve the performance of data dissemination, we study distributed data replication algorithms in VANETs for exchanging information and computing in an arbitrarily-connected network of vehicle nodes. To achieve low dissemination delay and improve the network performance, we control the number of message copies that can be disseminated in the network and then propose an efficient distributed data replication algorithm (EDDA). The key idea is to let the data carrier distribute the data dissemination tasks to multiple nodes to speed up the dissemination process. We calculate the number of communication stages for the network to enter into a balanced status and show that the proposed distributed algorithm can converge to a consensus in a small number of communication stages. Most of the theoretical results described in this paper are to study the complexity of network convergence. The lower bound and upper bound are also provided in the analysis of the algorithm. Simulation results show that the proposed EDDA can efficiently disseminate messages to vehicles in a specific area with low dissemination delay and system overhead. [ABSTRACT FROM AUTHOR]

The accurate voltage measurement of distribution networks is of great significance in power dispatching and fault diagnosis. Voltage sensors based on the spatial electric field effect do not require grounding, which provides the possibility for the distributed measurement of transmission line voltages. However, the divider ratio of suspension grounding voltage sensors is affected by the height between the sensor and the ground, as well as the distance between the sensor and the telegraph pole. In this paper, a self-calibration method based on internal capacitance transformation is proposed to realize the on-line calibration of suspension grounding voltage sensors. The calibration is accomplished by switching different parameters in the conditioning circuit, and the calibration process does not require power failure or known input excitation. In addition, the impact of electric fields in the other two phases of three-phase transmission lines on measurement through simulation research is quantified in this paper. In order to reduce the impact of interference electric fields, an equipotential shielding structure is designed. The circuit topology and probe prototype have been developed and testing has been conducted in laboratory conditions; the experimental results show that the maximum relative error of voltage amplitude is 1.65%, and the phase relative error is 0.94%. The measurement accuracy is not limited by the height to ground or the distance to the telegraph pole. In addition, in the application of an equipotential shielding probe, the maximum deviation of measured voltage is 0.7% with and without interference electric fields. [ABSTRACT FROM AUTHOR]

The cellulose content in vegetable waste (VW) is high and cannot be directly digested by black soldier fly larvae (BSFL). In this study, in order to treat VW using BSFL composting, kitchen waste (KW) is used as the only nutritional supplement for VW to analyze the effects of the different contents of crude protein (CP), crude fat (EE), carbohydrate (3C), compost thickness (CT), and treatment time on the larval weight (LW), survival rate (SR), dry matter reduction rate (DMR), bioconversion rate (BCR), physical and chemical properties of BSFL sand and changes in the microbial community. Our results showed that when the average 3C content increased by 40%, the average LW increased by 47.6%, and the SR, DMR, BCR, and organic matter (OM) content increased by 16.82%, 8.5%, 4.77%, and 3.86%, respectively. In contrast, when the average compost thickness increased by 5 cm, the average weight of BSFL decreased by 22.64%, while the SR of larvae, DMR, BCR, OM, and total nutrients (TN + P 2 O 5 + K 2 O) decreased by 5%, 5.2%, 4.42%, 9.6%, and 0.78%, respectively. Germination test showed that BSFL sand alone could not be used as soilless culture substrate. After BSFL treatment, we found that the dominant phyla in BSFL sand were Firmicutes (95.77%), Proteobacteria (2.54%), Actinobacteria (0.74%), and Chloroflexi (0.6%). Our results indicate that BSFL composting is an effective method of treating VW, and 3C content and CT have a significant effect on BSFL composting. [Display omitted] • 3C content and CT had significant effects on LW, SR, DMR, BCR and FCR. • 3C (129.34 g), CT (5 cm) and time (10 days) are suitable for BSFL composting. • BSFL sand cannot be directly used as soilless culture substrate. • Firmicutes (95.77%) was the most abundant gate in the BSFL sand. [ABSTRACT FROM AUTHOR]

This paper presents an optimized design and preliminary test result of a high-power input coupler. The design is motivated by five-cell Petra-type cavities operating in the Southern Advanced Photon Sources booster. We optimize the design of the high-power input coupler from the prototype, including the window geometry redesign and multipacting analysis to meet a 250 kW operation power upgrade plan. The cooling system of the coupler is redesigned to achieve a low temperature in high-power operation. Design results fulfill the five-cell cavity operation requirement. The corresponding waveguide and coaxial transition structures are developed and tested. We also describe the coupler's coupling coefficient tests and high-power test plans. [ABSTRACT FROM AUTHOR]

The bare conductor in switchgear constitutes complicated air gaps, and their AC withstand characteristic will obviously affect switchgear insulation performance. In this paper, AC withstand tests of various types of air gap were carried out. The air gap samples were rod-plane air gap and 4 typical types of air gap from the bus chamber of 40.5 kV metal-enclosed switchgear. The samples were tested in climate chamber where high altitude environment was simulated. And correction of withstand voltage for switchgear air gaps at low air pressure were conducted. Test results indicate that, the withstand characteristic of 4 typical types of air gap in switchgear are different from that of rod-plane air gap. The relationship between withstand voltage Uw and air gap distance d is nonlinear. The influencing characteristic exponent n of air pressure on Uw is related with air gap type. Linearity value m and air pressure index n are independent to some degree. An equation was proposed to express the relationship of Uw with air gap distance d and altitude H, and this equation can be used to calculate the safety distance of air gaps in switchgear under low air pressure situations. The results are significant for the design and selection of switch devices. [ABSTRACT FROM PUBLISHER]

Three-phase four-wire power cables are a primary kind of power transmission method in low-voltage distribution networks. This paper addresses the problem that calibration currents are not easily electrified during the transporting of three-phase four-wire power cable measurements, and proposes a method for obtaining the magnetic field strength distribution in the tangential direction around the cable, finally enabling online self-calibration. The simulation and experimental results show that this method can self-calibrate the sensor arrays and reconstruct the phase current waveforms in three-phase four-wire power cables without calibration currents, and this method is not affected by disturbances such as wire diameter, current amplitudes, and high-frequency harmonics. This study reduces the time and equipment costs required to calibrate the sensing module compared to related studies using calibration currents. This research offers the possibility of fusing sensing modules directly with running primary equipment, and the development of hand-held measurement devices. [ABSTRACT FROM AUTHOR]

Calreticulin (CRT) on the cell surface that acts as an "eat me" signal is vital for macrophage-mediated programmed cell removal. The polyhydroxylated fullerenol nanoparticle (FNP) has appeared as an effective inducer to cause CRT exposure on cancer cell surface, but it failed in treating some cancer cells such as MCF-7 cells based on previous findings. Here, we carried out the 3D culture of MCF-7 cells, and interestingly found that the FNP induced CRT exposure on cells in 3D spheres via re-distributing CRT from endoplasmic reticulum (ER) to cell surface. Phagocytosis experiments in vitro and in vivo illustrated the combination of FNP and anti-CD47 monoclonal antibody (mAb) further enhanced macrophage-mediated phagocytosis to cancer cells. The maximal phagocytic index in vivo was about three times higher than that of the control group. Moreover, in vivo tumorigenesis experiments in mice proved that FNP could regulate the progress of MCF-7 cancer stem-like cells (CSCs). These findings expand the application of FNP in tumor therapy of anti-CD47 mAb and 3D culture can be used as a screening tool for nanomedicine. [Display omitted] • Fullerenol nanoparticle (FNP) reduces the toxicity of anti-CD47 antibodies therapy. • 3D culture enhances the sensitivity of MCF-7 cells to FNP. • FNP inhibits the progression of MCF-7 cancer stem cells. [ABSTRACT FROM AUTHOR]

The usage of medium‐voltage switchgear is more and more common in high altitude areas. Few relative standards about the selection of switchgear air gap in low air pressure conditions are currently available for referring. In this study, four different types of switchgear air gaps, as well as a typical rod‐plane gap, are taken as the samples, and their positive and negative lightning strike discharge characteristics under low air pressure are tested in the artificial climate chamber. The effects of the electrode structure, polarity, air pressure, humidity, and gap distance on the discharge performances are analysed as well. Research results indicate that the four switchgear air gaps and typical rod‐plane gap differs greatly in lightning impulse discharge performances and polarity effects. In low air pressure conditions, the lightning impulse breakdown voltage of either positive or negative polarity can be corrected by U50 = U50,0 × (P/P0)n. The discharge voltage under positive lightning impulse is more easily affected by air pressure than that under negative lightning impulse. Atmosphere humidity will cause dispersiveness of air‐gap lightning impulse discharge voltage, which performs to be non‐linear with a gap distance lower under 400 mm. Research results are referable for the design, selection and installation of medium‐voltage switchgear in high altitude areas. [ABSTRACT FROM AUTHOR]

Macrophages are key responders of inflammation and are closely related with oxidative stress. Activated macrophages can enhance oxygen depletion, which causes an overproduction of reactive oxygen species (ROS) and leads to further excessive inflammatory response and tissue damage. Agmatine, an endogenous metabolite of L-arginine, has recently been shown to have neuroprotective effects based on its antioxidant properties. However, the antioxidant effects of agmatine in peripheral tissues and cells, especially macrophages, remain unclear. In this study we explored the role of agmatine in mediating antioxidant effects in RAW 264.7 cells and studied its antioxidant mechanism. Our data demonstrate that agmatine is an activator of Nrf2 signaling that markedly enhances Nrf2 nuclear translocation, increases nuclear Nrf2 protein level, up-regulates the expression of the Nrf2 downstream effector HO-1, and attenuates ROS generation induced by Lipopolysaccharide (LPS). We further demonstrated that the agmatine-induced activation of Nrf2 is likely through the PI3K/Akt pathway. LY294002, a specific PI3K/Akt inhibitor, abolished agmatine-induced HO-1 up-regulation and ROS suppression significantly. Inhibiting HO-1 pathway significantly attenuated the antioxidant effect of agmatine which the products of HO-1 enzymatic activity contributed to. Furthermore, the common membrane receptors of agmatine were evaluated, revealing that α2-adrenoceptor, I1-imidazoline receptor or I2-imidazoline receptor are not required by the antioxidant properties of agmatine. Taken together, our findings revealed that agmatine has antioxidant activity against LPS-induced ROS accumulation in RAW 264.7 cells involving HO-1 expression induced by Nrf2 via PI3K/Akt pathway activation. [ABSTRACT FROM AUTHOR]

• The way for arterial and venous thrombus are treated should also be varied. • Smaller system favors penetration, while larger one promotes trapping in thrombus. • Physical-matched nano-systems show advances in specific arteriovenous thrombolysis. The differences of physiology, fluid parameters and core structures of thrombus in artery and vein determine the distinct ways for arterial and venous thrombolytic treatments. As an effective drug delivery strategy, physical-matching of nano-delivery system and clot structure will lead to significant advances in specific arteriovenous thrombolysis treatment. We fabricated mesoporous silicon nanoparticles (MSNs) with different sizes (MSN-S: ∼40 nm, MSN-M: ∼70 nm, MSN-L: ∼110 nm) cloaked with platelet membrane (termed PNPs). Results demonstrated that PNP-S (small-sized PNP) exhibited the optimal penetration effect in the both carotid arterial thrombus and deep venous thrombosis (DVT) rat model. However, the enrichment effects in the arterial and venous thrombus were distinct. Upon the action of blood flow shear stress, PNP-S had a better enrichment effect in the carotid arterial thrombus rat model compared with the other groups, while PNP-L (large-sized PNP) showed the best penetration and enrichment efficiency in the DVT rat model. After loading with 100 U/g urokinase (UK) (termed UNPs), large-sized UNPs (UNP-L) and small-sized UNPs (UNP-S) respectively yielded the best thrombolytic effect in the DVT and carotid arterial thrombus rat model, which was near to that of high-dose UK (200 U/g). These results revealed that the physical-matching brought by size adjustment optimized the penetration and retention of nano-delivery system in various thrombi, and eventually enabled specific and effective arteriovenous thrombolysis. [ABSTRACT FROM AUTHOR]

The tracking and positioning of transmission lines is a key element for UAVs (Unmanned Aerial Vehicles) to achieve autonomous inspection of transmission lines. Current methods are vulnerable to weather and environmental factors, have high costs, and have difficulties in data processing. Therefore, this paper proposes a transmission line tracking and localization method based on the electric field sensor array, which calculates the current UAV's heading angle deflection angle, the distance between the transmission line and the UAV, and the elevation angle, providing a new idea to solve the problem of UAV inspection of transmission lines. At the same time, the electric field distribution of different arrangements of three-phase transmission lines was analyzed using COMSOL to determine the flight area of the UAV. By comparing the electric field distribution of the UAV flight area and single-phase transmission lines, it was verified that the current method is also applicable in the three-phase transmission line scenario, and it was further verified that the sensor array used can sense the change of the UAV position in the flight area, indicating that the electric field sensor array can realize the transmission line tracking and localization of transmission lines. The experimental results showed that, in the three-phase transmission line scenario, when the sensor array moves along the transmission straight wire, the maximum absolute error of the heading angle deflection angle calculated according to this method was 8.2°, the maximum absolute error of the distance between the array and the transmission line was 19.3 cm, and the maximum absolute error of the elevation angle was 11.37°; the error was within a reasonable range and can be used for the UAV to realize autonomous inspection. [ABSTRACT FROM AUTHOR]