Editorial: Neural & Bio-inspired Processing and Robot Control

201901 bcrcVersion of RecordPublishe

Experiments on a New Material for the Ecological Protection of Rock Slopes

AbstractFrom 2000, people use the ecological protection to reinforce rock slopes. These ecological protection methods not only can reduce the usage of concrete, but also can restore the degraded ecosystem of slopes. With the rapid development of infrastructures, many materials for ecological protection have been created. However, there are many defects in these materials, such as expensive price, weak strength in early period, easily slide or been eroded when encountered with rainfall. These defects are the problems awaiting solution in the development of slope ecological protection. In this paper, the author attempts to use cement as adhesive in a new material for the ecological protection, and carry out laboratory tests and field tests to verify the feasibility and reliability of this material. Based on existing research and the testing results, the author proposed the prescription of this new material, which can satisfy the survival requirement of vegetation on the slopes, lower costs and enhance the strength in early period of ecological protection as well

Modeling percentages of cohesive and adhesive debonding in bitumen-aggregate interfaces using molecular dynamics approaches

When an asphalt mixture cracks, adhesive debonding occurs along bitumen-mineral interfaces and cohesive debonding occurs within bitumen films. At microscale, the two debonding processes can happen simultaneously but it is unknown for their percentages. This study aims to determine the percentages for cohesive and adhesive debonding and investigate how the material and external factors can affect these percentages using molecular dynamics (MD) modeling. The pull-off simulations of bitumen-calcite interfaces were performed at different bitumen film thicknesses, pull-off velocities and temperatures. The percentages of cohesive debonding were calculated as the area ratio of the remained bitumen molecules over the total interface. Results show that the percentage of cohesive debonding increases from 29% to 65% with thicker bitumen films, and decreases from 86% to 59% with higher loading velocities. When temperature rises, the percentage of cohesive debonding increases from 61.3% to 88.2%. Quartz presents a weak adhesion to bitumen, and thus a complete (100%) adhesive debonding occurs regardless of bitumen thickness. Microcline shows a very strong adhesion to bitumen due to its high polarity. The modeled cohesive debonding percentage with different variables were verified and found consistent with the laboratory pull-off testing results available from the existing studies

Electron transport properties of the transition metal dichalcogenides composite WX

We have investigated the electronic structure and transport properties of the transition metal dichalcogenides composite WX2-MoX2 (X≡S, Se, Te) nanowires under the external strain, in the method of the first-principles calculation combining the Density functional theory (DFT) and the Non-equilibrium Green’s function (NEGF). First, we have designed the two terminal electron transport devices based on the stable transition metal dichalcogenides (TMDs) WX2-MoX2 (X≡S, Se, Te) composite nanowires for the first time. Second, the electronic structure and transport properties of the WS2-MoS2 composite nanowire have been demonstrated to be more sensitive to the external strain when compared to that of the composite WSe2/Te2-MoSe2/Te2 nanowires, the external compressive strain may significantly enchance the differential negative resistance (DNR) effect of the WSe2-MoSe2 composite nanowire based device, while the stretch strain should induce the interesting DNR in the WTe2-MoTe2 composite nanowire device. Finally, the obtained results have been physically explained from the integral area of the transmission coefficient in the bias voltage window, and may be of importance in the design of the nanoelectronic devices based on transition metal dichalcogenides composites

Imidazo[1,2-a]pyridine derivatives synthesis from lignin β-O-4 segments via a one-pot multicomponent reaction

Summary: The catalytic conversion of lignin into N-containing chemicals is of great significance for the realization of value-added biorefinery concept. In this article, a one-pot strategy was designed for the transformation of lignin β-O-4 model compounds to imidazo[1,2-a]pyridines in yields up to 95% using 2-aminopyridine as a nitrogen source. This transformation involves highly coupled cleavage of C-O bonds, sp3C-H bond oxidative activation, and intramolecular dehydrative coupling reaction to construction of N-heterobicyclic ring. With this protocol, a wide range of functionalized imidazo[1,2-a]pyridines sharing the same structure skeleton as those commercial drug molecules, such as Zolimidine, Alpidem, Saripidem, etc., were synthesized from different lignin β-O-4 model compounds and one β-O-4 polymer, emphasizing the application feasibility of lignin derivatives in N-heterobicyclic pharmaceutical synthesis

Rapid extraction of pavement aggregate gradation based on point clouds using deep learning networks

Usage of asphalt mixture with poor gradation will most likely lead to pavement deficiency. There is a growing need for rapid and non-destructive methods to extract pavement aggregate gradation. In this study, a deep learning-based method that utilizes point clouds data for gradation extraction was proposed. Firstly, a data enhancement algorithm along with three data format conversion methods (aligned point cloud, voxel, and depth image) were proposed to preprocess the original collected point clouds. Subsequently, different neural network models were designed for each data format to extract gradation. Finally, a multi-feature fusion network was developed, which using extraction network as the backbone and additional auxiliary information. In the case study, the MAE loss of multi-feature fusion networks with PointNet, Vox-ResNet34 and GoogLeNet-v4 as the backbone respectively achieved 0.202, 0.142 and 0.046 on the test set, which means an estimation accuracy of more than 95% for the pavement aggregate gradation.AI SingaporeNational Research Foundation (NRF)Submitted/Accepted versionThis paper is part of the research work of National Key Research and Development Project of China (Grant No. 2021YFB2600601, 2021YFB2600600). The authors would like to acknowledge the financial support provided by the National Natural Science Foundation of China (Grant No. 51922030), Natural Science Foundation of Jiangsu (Grant No. BK20220845), “the Fundamental Research Funds for the Central Universities” (Grant No. 2242022R10019). This research is also supported by the National Research Foundation, Singapore under its AI Singapore Programme (AISG Award No: AISG2-TC-2021-001)

Successive Cleavage and Reconstruction of Lignin beta-O-4 Models and Polymer to Access Quinoxalines

The construction of N-heterocyclic compounds from lignin remains a great challenge due to the complex lignin structure and the involvement of multiple steps, including the cleavage of lignin C-O linkages and the formation of heterocyclic aromatic rings. Herein, the first example of KOH mediated sustainable synthesis of quinoxaline derivatives from lignin β-O-4 model compounds in a one-pot fashion under transition-metal-free conditions has been achieved. Mechanistic studies suggested that this transformation includes highly coupled cascade steps of cleavage of C-O bonds, dehydrative condensation, sp3 C-H bond oxidative activation, and intramolecular dehydrative coupling reaction. With this protocol, a wide range of functionalized quinoxalines, including an important drug compound AG1295, were synthesized from lignin β-O-4 model compounds and β-O-4 polymer, showcasing the application potential of lignin in pharmaceutical synthesis

In-Channel and In-Plane Li Ion Diffusions in the Superionic Conductor Li₁₀GeP₂S₁₂ Probed by Solid-State NMR

Li₁₀GeP₂S₁₂ (LGPS) is a new solid electrolyte of the highest Li ionic conductivity reported as of now. An anisotropic 3D Li ionic transport network consisting of an ultrafast Li 1D diffusion tunnel and fast in-plane 2D pathways was previously predicted by molecular dynamics simulations. In this paper, we have studied in detail the Li ion dynamics in LGPS by multiple solid-state NMR methods. Two different Li motion processes, characterized by apparently different activation energies of 0.16 eV and 0.26 eV, were unambiguously probed by both ⁷Li and ³¹P solid-state NMR and assigned to Li ion diffusions in the 1D tunnel and in the 2D plane, respectively. ³¹P spin-locking relaxation measurement further reveals that interstitial position Li(4) is active for in-plane Li migration