Optimum design of printed electronics inkjet printer using response surface model and multi-objective genetic algorithm

The purpose of this project is to improve the optimization design of complex mechanical structure based on the combination of response surface model and multi-objective genetic algorithm (MOGA). First of all, we built the finite element model (FEM) for the printed electronics inkjet printer through experimental modal analysis (EMA) and finite element analysis (FEA). The analysis of the static and dynamic characteristics of the FEM confirms the weak points of the structure and its actual performance. Next, using central composite design (CCD) method, it selects sample points in the design space and carries out numerical simulation and establishes the initial second order response surface model with eight design variables to further determine the inkjet printer’s first order natural frequency, weight and maximum deformation of the inkjet head. Finally, it carries out an approximation optimization of response surface model using MOGA to obtain the Pareto optimal solution set. Our simulation results determine that the optimal solution can increase the first order natural frequency of the inkjet printer by 36.3 % to effectively avoid the resonance region caused by the servo motor excitation. The maximum deformation of inkjet head decreases by 33 % and the weight of the inkjet printer can be reduced by 19.5 %. We believe that optimization can improve the performance of the inkjet printer and reduce its weight at the same time. The method proposed in this study is suitable for multi-objective optimization of complex structures similar to the printed electronics inkjet printer

Structure of the catalytic region of DNA ligase IV in complex with an Artemis fragment sheds light on double-strand break repair.

Nonhomologous end joining (NHEJ) is central to the repair of double-stranded DNA breaks throughout the cell cycle and plays roles in the development of the immune system. Although three-dimensional structures of most components of NHEJ have been defined, those of the catalytic region of DNA ligase IV (LigIV), a specialized DNA ligase known to work in NHEJ, and of Artemis have remained unresolved. Here, we report the crystal structure at 2.4 Å resolution of the catalytic region of LigIV (residues 1-609) in complex with an Artemis peptide. We describe interactions of the DNA-binding domain of LigIV with the continuous epitope of Artemis, which, together, form a three-helix bundle. A kink in the first helix of LigIV introduced by a conserved VPF motif gives rise to a hydrophobic pocket, which accommodates a conserved tryptophan from Artemis. We provide structural insights into features of LigIV among human DNA ligases

Output Voltage Response Improvement and Ripple Reduction Control for Input-parallel Output-parallel High-Power DC Supply

A three-phase isolated AC-DC-DC power supply is widely used in the industrial field due to its attractive features such as high-power density, modularity for easy expansion and electrical isolation. In high-power application scenarios, it can be realized by multiple AC-DC-DC modules with Input-Parallel Output-Parallel (IPOP) mode. However, it has the problems of slow output voltage response and large ripple in some special applications, such as electrophoresis and electroplating. This paper investigates an improved Adaptive Linear Active Disturbance Rejection Control (A-LADRC) with flexible adjustment capability of the bandwidth parameter value for the high-power DC supply to improve the output voltage response speed. To reduce the DC supply ripple, a control strategy is designed for a single module to adaptively adjust the duty cycle compensation according to the output feedback value. When multiple modules are connected in parallel, a Hierarchical Delay Current Sharing Control (HDCSC) strategy for centralized controllers is proposed to make the peaks and valleys of different modules offset each other. Finally, the proposed method is verified by designing a 42V/12000A high-power DC supply, and the results demonstrate that the proposed method is effective in improving the system output voltage response speed and reducing the voltage ripple, which has significant practical engineering application value.Comment: Accepted by IEEE Transactions on Power Electronic

Bayesian Optimized 1-Bit CNNs

Deep convolutional neural networks (DCNNs) have dominated the recent developments in computer vision through making various record-breaking models. However, it is still a great challenge to achieve powerful DCNNs in resource-limited environments, such as on embedded devices and smart phones. Researchers have realized that 1-bit CNNs can be one feasible solution to resolve the issue; however, they are baffled by the inferior performance compared to the full-precision DCNNs. In this paper, we propose a novel approach, called Bayesian optimized 1-bit CNNs (denoted as BONNs), taking the advantage of Bayesian learning, a well-established strategy for hard problems, to significantly improve the performance of extreme 1-bit CNNs. We incorporate the prior distributions of full-precision kernels and features into the Bayesian framework to construct 1-bit CNNs in an end-to-end manner, which have not been considered in any previous related methods. The Bayesian losses are achieved with a theoretical support to optimize the network simultaneously in both continuous and discrete spaces, aggregating different losses jointly to improve the model capacity. Extensive experiments on the ImageNet and CIFAR datasets show that BONNs achieve the best classification performance compared to state-of-the-art 1-bit CNNs

Benthic Habitat Quality Assessment in Estuarine Intertidal Flats Based on Long-Term Data with Focus on Responses to Eco-Restoration Activity

A long-term assessment of the benthic habitat quality of intertidal flats in Liaohe Estuary was conducted by three integrating ecological indices, AZTI’s Marine Biotic Index (AMBI), Multivariate-AMBI (M-AMBI), and Shannon–Wiener diversity index (H′) based on macrobenthos data from 2013 to 2020. The results showed that the macrobenthic communities were characterized by indifferent and sensitive species of AMBI ecological groups. The annual ranges of H′, AMBI, and M-AMBI were 0.77–1.56, 1.44–3.73 and 0.36–0.54, respectively. Noticeable differences were found among assessment obtained by these biotic indices. Approximately 100%, 24%, and 78% sampling sites had “moderate”, “poor”, and “bad” statuses as assessed by H′, AMBI, and M-AMBI, respectively. Compared with H′ and AMBI, M-AMBI may be more applicable to evaluate the benthic habitat quality of intertidal flats in Liaohe Estuary. Results suggest that the benthic habitat quality in the middle parts of intertidal flats still had an unacceptable status and has not improved radically to date after large-scale “mariculture ponds restored to intertidal flats”.publishedVersio

Detection of a parsec-scale jet in a radio-quiet narrow-line Seyfert 1 galaxy with highly accreting supermassive black hole

The jet in active galactic nuclei (AGN) is a key ingredient in understanding the co-evolution of galaxies and their central supermassive black holes (SMBHs). Unfortunately, the mechanism of jet launching and collimation is still elusive. The observational evidence of decreasing radio loudness with increasing Eddington ratio implies that the jet should be coupled with the accretion process. To further explore the relationship between the jet and accretion, it is necessary to extend our knowledge of the jet to an extreme end of the Eddington ratio distribution of AGN. Using Very Long Baseline Array (VLBA), we report the detection of the parsec-scale radio structure in Mrk 335, a radio-quiet narrow-line Seyfert 1 galaxy with an Eddington ratio close to/above unity. The VLBA image at 1.5 GHz reveals an elongated structure extending ∼20 pc in north-south direction with a peak flux density of 1.98 \ub1 0.05 mJy beam-1 and radio brightness temperatures as high as 6 7 107 K. This feature provides a strong evidence of a parsec-scale (bipolar) jet launched from a highly accreting SMBH. We discuss the result by comparing Mrk 335 with other highly accreting systems, e.g. Galactic black holes and tidal disruption events, and recall the discovery of collimated corona in the vicinity of SMBH in Mrk 335 by previous X-ray observations, whose relation to the parsec-scale radio jet should be explored by future simultaneous X-ray spectroscopy and high resolution radio observations

Radio activity of supermassive black holes with extremely high accretion rates

Radio emission from the high- and super-Eddington accreting active galactic nuclei (AGNs) has various origins: a persistent jet, the magnetized corona and the wind-like outflows. It is now still unclear which is the leading mechanism responsible for the observed radio emission and how the radio emission is related to other characteristic parameters such as the Eddington ratio and black hole mass. In this paper, we present the 5 GHz Very Large Array (VLA) observational results of a sample of 25 extremely high Eddington accreting supermassive black holes (EESBHs, the Eddington ratio close to or above one) from narrow-line Seyfert 1 galaxies, among which 22 sources are detected. Most of EESBHs show a compact radio structure from a few hundred parsecs to one-kiloparsec scale. We estimated the lowest star formation rate surface density required for producing the observed radio emission, and found it is higher than the largest value previously detected in circumnuclear starburst galaxies, implying that the radio emission is from the AGN activity. Along with a comparison sample, we find an overall inverse radio loudness and Eddington ratio correlation ranging from sub- to super-Eddington ratios. The high-Eddington and mildly super-Eddington AGNs (-0.5<log lambda_Edd<0.6) have a radio to X-ray luminosity ratio L_R/L_X~10^-5 to 10^-4 and a steep radio spectrum, supporting that the radio emission is from transient ejecta (outflows) of corona, however, the jet contribution cannot be fully ruled out. Our highly super-Eddington sources (log lambda_Edd>~0.6) have a flatter radio spectrum, along with its low radio luminosity: L_R/L_X~10^-5, their radio emission is likely dominated by a magnetized corona, and a radiation pressure caused jet is also proposed in this paper.Comment: 17 pages, 8 figures, 5 tables, submitted to Ap

Controlling the 2D magnetism of CrBr3_3 by van der Waals stacking engineering

The manipulation of two-dimensional (2D) magnetic order is of significant importance to facilitate future 2D magnets for low-power and high-speed spintronic devices. Van der Waals stacking engineering makes promises for controllable magnetism via interlayer magnetic coupling. However, directly examining the stacking order changes accompanying magnetic order transitions at the atomic scale and preparing device-ready 2D magnets with controllable magnetic orders remain elusive. Here, we demonstrate effective control of interlayer stacking in exfoliated CrBr$_3$ via thermally assisted strain engineering. The stable interlayer ferromagnetic (FM), antiferromagnetic (AFM), and FM-AFM coexistent ground states confirmed by the magnetic circular dichroism measurements are realized. Combined with the first-principles calculations, the atomically-resolved imaging technique reveals the correlation between magnetic order and interlay stacking order in the CrBr$_3$ flakes unambiguously. A tunable exchange bias effect is obtained in the mixed phase of FM and AFM states. This work will introduce new magnetic properties by controlling the stacking order, and sequence of 2D magnets, providing ample opportunities for their application in spintronic devices.Comment: 7 pages, 4 figure

Study on optimization of nano-coatings for ultra-sensitive biosensors based on long-period fiber grating

Bio-chemical sensors are expected to offer high sensitivity and specificity towards the detection of an analyte. It has been found that optical sensors based on long period fiber gratings (LPFGs) meet most of these requirements, particularly when coated with thin and high-refractive index overlays with proper bio-functionalization. In this paper, the influence of properties of the overlay material on the sensitivity of LPFG sensors to bio-analytes is analyzed. It has been observed that the sensitivity of a particular cladding mode of LPFG can be changed drastically with the adhesion of few tens of ‘nm’ of bio-layers to the surface of LPFG. “Volume refractive index sensitivity” and “add-layer sensitivity” of a particular cladding mode, dynamic range, and limit of detection of the sensors have been investigated in the context of overlay materials, bio-functionalization steps, and surrounding buffer medium. The selection criteria of the thin-film deposition technique are discussed with the aim of designing highly sensitive sensors for biological and chemical applications. Concept of optimum overlay thickness has been redefined and an effective case-specific design methodology is proposed