Generalized laws of reflection and refraction from transformation optics

Based on transformation optics, we introduce another set of generalized laws of reflection and refraction (differs from that of [Science 334, 333 (2011)]), through which a transformation media slab is derived as a meta-surface, producing anomalous reflection and refraction for all polarizations of incident light.Comment: 7 pages, 3 figure

Research on Situation, Problems and Measures of Land Indicator in Rural Implementation

Through field research of Huimin Subdistrict, Ba’nan District, Chongqing, the paper analyzes collected basic data and describes the exposed problem of land indicator in rural operation: The process of “turn country into city” is slow, government credibility drops; the area before and after surveying is different, which intensifies the contradiction between town government and individuals; peasants expand ancillary facility land of homestead; peasants are too old, so they cannot suit to urban life; land utilization efficiency after reclamation is not high; capital acquired by peasants don’t flow into country; the group fund supervision of village is difficult. The paper proposes four suggestions: clarify rural land property right and type and improve degree of accuracy of initial surveying; improve land indicator trade system and promote land indicator landing; look for good rural and agricultural project and vitalize fund; improve supervision system and realize publicity and transparency

Co-Salient Object Detection with Semantic-Level Consensus Extraction and Dispersion

Given a group of images, co-salient object detection (CoSOD) aims to highlight the common salient object in each image. There are two factors closely related to the success of this task, namely consensus extraction, and the dispersion of consensus to each image. Most previous works represent the group consensus using local features, while we instead utilize a hierarchical Transformer module for extracting semantic-level consensus. Therefore, it can obtain a more comprehensive representation of the common object category, and exclude interference from other objects that share local similarities with the target object. In addition, we propose a Transformer-based dispersion module that takes into account the variation of the co-salient object in different scenes. It distributes the consensus to the image feature maps in an image-specific way while making full use of interactions within the group. These two modules are integrated with a ViT encoder and an FPN-like decoder to form an end-to-end trainable network, without additional branch and auxiliary loss. The proposed method is evaluated on three commonly used CoSOD datasets and achieves state-of-the-art performance.Comment: Accepted by ACM MM 202

A Volume Comparison Estimate with Radially Symmetric Ricci Curvature Lower Bound and Its Applications

We extend the classical Bishop-Gromov volume comparison from constant Ricci curvature lower bound to radially symmetric Ricci curvature lower bound, and apply it to investigate the volume growth, total Betti number, and finite topological type of manifolds with nonasymptotically almost nonnegative Ricci curvature

Research on the Train-Bridge Coupled Vibration and Dynamic Performance of Steel Box Hybrid Girder Cable-Stayed Railway Bridge

Based on the Yongjiang Bridge, this paper used the numerical calculation and the field dynamic load test to study the coupled vibration and dynamic response of the steel box hybrid girder cable-stayed railway bridge. Each vehicle in the train was simulated with 31 degrees of freedom, and the oscillatory differential equation of vehicle-bridge coupling was established by MATLAB software. Afterwards, the field tests were also conducted to determine the free vibration characteristics as well as the strain, displacement, and acceleration of the bridge superstructure under trains moving at different speeds and braking at a specified position from a set speed. According to the dynamic load test and Vehicle-Bridge Coupling Vibration analysis, the following conclusions are obtained: (1) The calculated results of vehicle-bridge coupling vibration agreed well with the measured ones, and the program could be used to analyze the dynamic performance of Railway cable-stayed bridges with steel box composite girders. (2) The measured first-order natural frequencies of transverse, vertical and longitudinal vibration were 0,39 Hz; 0,49 Hz and 0,88 Hz, respectively. The dynamic coefficients are 1,04 – 1,13, the maximum lateral and vertical accelerations are 1,10 m/s2 and 1,11 m/s2, and the maximum derailment coefficient and load reduction rate are 0,55 and 0,39, respectively. These data showed that the dynamic parameters of bridges and vehicles met the requirements and had good stiffness and dynamic performance. (3) This paper, using the frequency limit of simply supported beam to restrain the natural frequencies of cable-stayed bridges is not appropriate, and it is necessary to propose the natural frequency limit value of cable-stayed bridge