Search

In this paper, a lightweight deep neural network (DNN) for direction of arrival (DOA) estimation is proposed, of which the input vector is designed to remove data redundancy as well as remaining DOA information. By exploring the Vandermonde property of the steering vector of a uniform linear array (ULA), the size of the newly designed input vector is greatly reduced. Furthermore, the DOA estimation is designed as a regression problem instead of a classification problem; that is, the lightweight DNN designs the output vector as the estimated DOAs of sources, of which the size is much shorter than that of the spatial spectrum used as the output vector in the conventional DNN. The reductions in the sizes of input and output vectors lead to a reduction in the sizes of hidden layers, achieving lightweightness of the neural network. The analysis illustrates that when the number of sensors is 22, the number of parameters in the lightweight DNN is three orders of magnitude less than that in the conventional DNN. The simulation results demonstrate the lightweight DNN can provide high DOA estimation accuracy with the shortest testing time. It performs better than the conventional DNN. Furthermore, it is superior to traditional solutions such as the multiple signal classification (MUSIC) method and conventional beamforming (CBF) method in harsh conditions like low signal-to-noise ratios (SNRs), closely spaced sources, and few snapshots. [ABSTRACT FROM AUTHOR]

With the rapid development of economy and society and the continuous optimization of industrial structure, the demand for high skilled talents is increasing. Education plays an irreplaceable role in China's economic growth. Therefore, it is of great significance to study the impact of talent supply of vocational education on economic growth from the perspective of human capital and comprehensively consider the spatial interaction of economic growth. Taking intelligent image recognition technology as the main research technology, this paper discusses the contribution of educational human capital to regional green economic growth. This paper expounds the content of intelligent image recognition technology, constructs an image recognition system based on neural network, and studies the relationship between human resource utilization efficiency and regional economy under intelligent image recognition technology based on the empirical analysis of intelligent image recognition technology. Finally, it makes an empirical study on the spatial effect in the image recognition system and expounds the relationship between feature space and economic growth. It verifies the relationship between educational human capital and green economic growth. The results show that the intelligent image recognition technology has a good effect in the research of spatial effect. [ABSTRACT FROM AUTHOR]

Aldehyde dehydrogenase 2 (ALDH2) plays important role in ethanol metabolism, and also serves as an important shield from the damage occurring under oxidative stress. A special inactive variant was found carried by 35–45% of East Asians. The variant carriers have recently been found at the higher risk for the diseases related to the damage occurring under oxidative stress, such as cardiovascular and cerebrovascular diseases. As a result, ALDH2 activators may potentially serve as a new class of therapeutics. Herein, N -benzylanilines were found as novel allosteric activators of ALDH2 by computational virtual screening using ligand-based and structure-based screening parallel screening strategy. Then a structural optimization was performed and has led to the discovery of the compound C6. It has good activity in vitro and in vivo , which could reduce infarct size by ∼70% in ischemic stroke rat models. This study provided good lead compounds for the further development of ALDH2 activators. Image 1 • Novel allosteric activators of ALDH2 were found by computational virtual screening. • Ligand-based and structure-based parallel virtual screening strategy was used. • Compound C6 with good activity was discovered by further structural optimization. • Compound C6 could reduce infarct size by ∼70% in ischemic stroke rat models. [ABSTRACT FROM AUTHOR]

Guo, J., 2020. Credit risk management and control in a maritime supply chain trade network. In: Gong, D.; Zhang, M., and Liu, R. (eds.), Advances in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 106, pp. 109–112. Coconut Creek (Florida), ISSN 0749-0208. Maritime transport is the link of international trade. In recent years, China's international trade volume has increased dramatically, and its marine transportation business has expanded rapidly. Its supply chain risk control system should also be upgraded to meet the market demand. This study finds that contract performance ability is the biggest source of risk. Through the comprehensive suggestions put forward in this paper, the risk rate of supply chain can be effectively controlled through property insurance, credit derivatives, and a reasonable project packaging scheme. At the same time, this paper suggests that the marine transportation supply chain should get rid of the limitation of the purchase contract and launch the supply chain products for retail to advantageous customers, which can reduce the comprehensive risk of the supply chain to a greater extent. [ABSTRACT FROM AUTHOR]

• The fracture behavior characteristics depend on defect type, intrinsic defect concentration and functional group coverage. • Epoxy functionalization is the most prevalent factor leading to graphene film breakage when ordered distribution of defects. • In epoxy group-dominated fracture, with epoxy group coverage at a threshold, fracture exhibits a pronounced ductile fracture. • Fractures dominated by topological defects have progressively more ductile properties as the density of defects increases. Introducing and regulating defects to prepare functional graphene has become a research hotspot. However, most studies focus on the mechanical properties of functional graphene or the influence of a single defect, which cannot reflect the influence of multiple coupled defects on mechanical properties. In this study, molecular dynamics methods were used to investigate the fracture behavior of graphene under the coupled effects of intrinsic defects such as vacancies, cracks, and topological defects, as well as external introduced defects such as epoxy groups and hydroxyl groups. The results showed that the fracture behavior of graphene is strongly related to the defects' type, concentration, and functionality. Under the same conditions, the epoxy group has the strongest leading effect on fracture, followed by cracks, Stone-Wales topological defects, and hydroxyl groups. Based on the tensile simulation of defect-ordered graphene, the critical relative concentrations and functionalities of different defect types leading to fracture were further quantified and validated using an amorphous distribution model. In addition, the fracture mode dominated by epoxy groups is related to its functionality. Excessive or insufficient functionality will exhibit strong brittle fracture characteristics, and when the functionality is at a certain threshold, it will exhibit obvious ductile fracture characteristics; while hydroxyl-dominated fracture presents brittle mode. Finally, the coupled fracture mechanism was analyzed from the aspects of bonding characteristics and system energy. The research results can provide reference and reference for the theoretical research and technological development of graphene. [ABSTRACT FROM AUTHOR]

We develop a procedure to identify magnetic flux ropes in Martian ionosphere using the MAVEN observations of magnetic field. Preliminary results show that the terminator play an important role on the distribution of flux ropes. On the dayside they are observed from 130 km to 300 km altitude and more frequently observed around ~170 km altitude. The flux ropes near the terminator are much denser than that in the sub-solar region. On the nightside (SZA > 100 deg), flux ropes are sparser and only observed below ~180 km altitude. This distribution suggest Kelvin-Helmholtz instability could be an important source of the flux ropes in the ionosphere. The characteristics of the ropes, such as field amplitude and diameter will be identified in subsequent study. [ABSTRACT FROM AUTHOR]

• New colchicine site inhibitors with locked bioactive configuration were found. • Compounds C1 and C2 showed potent inhibitory activity against tubulin polymerization. • C1 and C2 showed potent inhibitory activity against human colon cancer cell lines. • Compound C1 showed excellent broad-spectrum antitumor activity in the NCI-60 Screen. The colchicine site inhibitors (CSIs) displayed both antimitotic and vascular disrupting activities, therefore are promising potential antitumor agents. In this study, a series 1-phenyl-4,5-dihydro-2 H -benzo[ e ]indazoles were found as new CSIs of which the bioactive configuration was locked. Among them, compounds C1 and C2 displayed the best activity, with tubulin polymerization IC 50 of 3.4 and 1.5 μM, and growth IC50 of low nanomolar concentrations against human colon cancer cell lines. In addition, compound C1 showed excellent broad-spectrum antitumor activity in the NCI-60 Human Tumor Cell Lines Screen, encouraging further study of this antitumor compound. [ABSTRACT FROM AUTHOR]

Photo-catalytically converting the greenhouse gas CO2 into ethanol is an important avenue for the mitigation of climate issues and the utilization of renewable energies. Catalysts play critical roles in the reaction of photocatalytic CO2 conversion to ethanol, and a number of catalysts have been investigated, including semiconductors and plasmonic metal-based catalysts, as well as several other catalysts. In this review, the progress in the development of each category of catalysts is summarized, the current status is reviewed, the remaining challenges are pointed out, and the future research directions are prospected, with the aim being to pave pathways for the rational design of better catalysts. [ABSTRACT FROM AUTHOR]

Based on the analysis of the airborne bistatic synthetic aperture radar (SAR) imaging geometric mode, an extended nonlinear chirp scaling algorithm is employed to simulate and verify the imaging effect of the bistatic SARs. A gradient theory-based two-dimensional resolution bistatic SAR model is proposed, and the constraints of the multi-platform flight trajectory parameters meeting the imaging accuracy of the bistatic SAR are analyzed. Finally, through the bistatic SAR imaging simulation of cooperative flight trajectories under various situations, the spatial configuration constraint envelope between the flight vehicles to achieve the optimal resolution is revealed. The results of this paper will provide a theoretical reference for the SAR application in formation flight control. [ABSTRACT FROM AUTHOR]

Corrigendum to 'Synthesis and biological evaluation of 7-methoxy-1-(3,4,5-trimethoxyphenyl)-4,5-dihydro-2H-benzo[e]indazoles as new colchicine site inhibitors' [Bioorgan. Med. Chem. [Extracted from the article]