An Evaluation System for Agriculture and Tourism Coupling Degree of Rural Complex Based on Production-living-ecological Space

Rural complex is a bright spot for China to realize the development of new industries for rural revitalization.Starting from the concept,development history and current situation of rural complex,based on the perspective of production-living-ecological space,according to the different characteristics of agriculture and tourism,3 secondary indices and 18 tertiary indices were selected,and each of them was weighted using the Delphi expert consultation method and analytic hierarchy process(AHP)to construct an evaluation system for the coupling degree of agriculture and tourism in rural complex.The results show gross domestic product and forest coverage have the most significant impact on agriculture,economic benefits and the ecological water quality of tourist attractions have the most significant impact on the tourism industry,and tourism economic benefits and agricultural ecological benefits have the most significant impact on rural complex.

Label-free impedimetric immunosensor for point-of-care detection of COVID-19 antibodies

The COVID-19 pandemic has posed enormous challenges for existing diagnostic tools to detect and monitor pathogens.Therefore,there is a need to develop point-of-care(POC)devices to perform fast,accurate,and accessible diagnostic methods to detect infections and monitor immune responses.Devices most amenable to miniaturization and suitable for POC applications are biosensors based on electrochemical detection.We have developed an impedimetric immunosensor based on an interdigitated microelectrode array(IMA)to detect and monitor SARS-CoV-2 antibodies in human serum.Conjugation chemistry was applied to functionalize and covalently immobilize the spike protein(S-protein)of SARS-CoV-2 on the surface of the IMA to serve as the recognition layer and specifically bind anti-spike antibodies.Antibodies bound to the S-proteins in the recognition layer result in an increase in capacitance and a consequent change in the impedance of the system.The impedimetric immunosensor is label-free and uses non-Faradaic impedance with low nonperturbing AC voltage for detection.The sensitivity of a capacitive immunosensor can be enhanced by simply tuning the ionic strength of the sample solution.The device exhibits an LOD of 0.4 BAU/ml,as determined from the standard curve using WHO IS for anti-SARS-CoV-2 immunoglobulins;this LOD is similar to the corresponding LODs reported for all validated and established commercial assays,which range from 0.41 to 4.81 BAU/ml.The proof-of-concept biosensor has been demonstrated to detect anti-spike antibodies in sera from patients infected with COVID-19 within 1 h.

A characteristic-featured shock wave indicator for simulating high-speed inviscid flows on 3D unstructured meshes

In this work,we extend the characteristic-featured shock wave indicator based on artificial neuron training to 3D high-speed flow simulation on unstructured meshes.The extension is achieved through dimension splitting.This leads to that the proposed indicator is capable of identifying regions of flow compression in any direction.With this capability,the indicator is further developed to combine with h-adaptivity of mesh refinement to improve resolution with less computational costs.The present indicator provides an attractive alternative for constructing high-resolution,high-efficiency shock-processing methods to simulate high-speed inviscid flows.

A DDG Method with a Residual-Based Artificial Viscosity for the Transonic/Supersonic Compressible Flow

In this work,a direct discontinuous Galerkin(DDG)method with artificial viscosity is developed to solve the compressible Navier-Stokes equations for simulating the transonic or supersonic flow,where the DDG approach is used to discretize viscous and heat fluxes.A strong residual-based artificial viscosity(AV)technique is proposed to be applied in the DDG framework to handle shock waves and layer structures appearing in transonic or supersonic flow,which promotes convergence and robustness.Moreover,the AV term is added to classical BR2 methods for comparison.A number of 2-D and 3-D benchmarks such as airfoils,wings,and a full aircraft are presented to assess the performance of the DDG framework with the strong residualbased AV term for solving the two dimensional and three dimensional Navier-Stokes equations.The proposed framework provides an alternative robust and efficient approach for numerically simulating the multi-dimensional compressible Navier-Stokes equations for transonic or supersonic flow.