Distance in cone metric spaces and common fixed point theorems

AbstractIn this paper, we define a distance called c-distance on a cone metric space and prove a new common fixed point theorem by using the distance

An Implicit Iterative Scheme for an Infinite Countable Family of Asymptotically Nonexpansive Mappings in Banach Spaces

Let K be a nonempty closed convex subset of a reflexive Banach space E with a weakly continuous dual mapping, and let {Ti}i=1∞ be an infinite countable family of asymptotically nonexpansive mappings with the sequence {kin} satisfying kin≥1 for each i=1,2,…, n=1,2,…, and limn→∞kin=1 for each i=1,2,…. In this paper, we introduce a new implicit iterative scheme generated by {Ti}i=1∞ and prove that the scheme converges strongly to a common fixed point of {Ti}i=1∞, which solves some certain variational inequality

Methyl 2-[4-(4-chloro­benzo­yl)phen­oxy]-2-methyl­propano­ate

In the title compound, C18H17ClO4, the dihedral angle between the mean planes of the benzene rings is 53.4 (1)°. Weak inter­molecular C—H⋯O inter­actions are observed

NBMOD: Find It and Grasp It in Noisy Background

Grasping objects is a fundamental yet important capability of robots, and many tasks such as sorting and picking rely on this skill. The prerequisite for stable grasping is the ability to correctly identify suitable grasping positions. However, finding appropriate grasping points is challenging due to the diverse shapes, varying density distributions, and significant differences between the barycenter of various objects. In the past few years, researchers have proposed many methods to address the above-mentioned issues and achieved very good results on publicly available datasets such as the Cornell dataset and the Jacquard dataset. The problem is that the backgrounds of Cornell and Jacquard datasets are relatively simple - typically just a whiteboard, while in real-world operational environments, the background could be complex and noisy. Moreover, in real-world scenarios, robots usually only need to grasp fixed types of objects. To address the aforementioned issues, we proposed a large-scale grasp detection dataset called NBMOD: Noisy Background Multi-Object Dataset for grasp detection, which consists of 31,500 RGB-D images of 20 different types of fruits. Accurate prediction of angles has always been a challenging problem in the detection task of oriented bounding boxes. This paper presents a Rotation Anchor Mechanism (RAM) to address this issue. Considering the high real-time requirement of robotic systems, we propose a series of lightweight architectures called RA-GraspNet (GraspNet with Rotation Anchor): RARA (network with Rotation Anchor and Region Attention), RAST (network with Rotation Anchor and Semi Transformer), and RAGT (network with Rotation Anchor and Global Transformer) to tackle this problem. Among them, the RAGT-3/3 model achieves an accuracy of 99% on the NBMOD dataset. The NBMOD and our code are available at https://github.com/kmittle/Grasp-Detection-NBMOD

Synthesis and Characterization of ZnTe Hierarchical Nanostructures

Single-crystalline ZnTe hierarchical nanostructures have been successfully synthesized by a simple thermal evaporation technology. The as-prepared products were characterized with X-ray diffraction (XRD), scanning electron microcopy (SEM), transmission electron microscope (TEM), and photoluminescence spectrum (PL). These results showed that the ZnTe hierarchical nanostructures consisted of nanowires and nanolumps. The room temperature PL spectrum exhibited a pure green luminescence centered at 545nm. The growth mechanism of hierarchical nanostructure was also discussed

Deformation Stability Response of Adjacent Subway Tunnels considering Excavation and Support of Foundation Pit

AbstractSince the safety and stability of the original tunnel structure are easily affected by the adjacent foundation pit excavation, it is strongly necessary to study the deformation evolution of tunnels during the adjacent foundation pit excavation. With regard to the two cases that tunnel is adjacently located at the right and bottom of foundation pit, the influence of different supporting methods, including pile support, bolt support, pile-bolt support, and shotcrete-bolt support, on the tunnel stability was investigated on the basis of the whole excavation process numerical simulation of deep foundation pit for determining the best foundation pit supporting beneficial to the stability of adjacent tunnel. The results indicate that both one-step excavation and multistep excavation have great influences on the displacement of adjacent tunnels, wherein the influences on the tunnel located at the right of foundation pit are greater than those at the bottom of foundation pit. Multistep excavation is recommended for the foundation pit adjacent to shallow tunnel. In the case of the tunnel located on the bottom of the foundation pit, the maximum stress generated around the tunnel is small, the maximum stress area is limited, and the displacement of tunnel monitoring points is also small. For the tunnel located at the right of the foundation pit, the pile-bolt supporting can effectively limit the displacement of soil between the tunnel and the foundation pit, reduce the maximum stress and the maximum stress distribution area, and effectively control the tunnel displacement

Structure and Properties of Biodegradable Polymer Materials for Fused Deposition Modeling 3D Printing

The properties of 3D printed products are closely related to the raw materials and the processes by which they are made. The processes of melting, depositing, and cooling of polymers affect the orientation, crystallinity, and microstructure of the product. These in turn influence the thermal, mechanical, optical, and other properties of the printed part. Among various 3D printing methods, filament and pellet extrusion-based fused deposition modeling (FDM) 3D printing is the cheapest and mostly adopted. In this chapter, the devices and some biodegradable polymer materials applicable in FDM 3D printing are briefly introduced. In the first part, preparation and the structure-property relationship of polylactic acid/polybutylene succinate blend filaments are discussed. Rheological, thermal properties of the raw materials and the properties of the printed parts were characterized. In the second part, a pellet extrusion 3D printer with a micro-screw was designed for using pellets of polyhydroxyalkanoate composites, which are difficult to produce filaments. The relationship between the screw parameters of the micro-screw extrusion 3D printer, rheological properties of the composites, and the printed product performance has been investigated. Combining theory and practical application will provide guidance for formulating biodegradable polymer materials and designing equipment for FDM 3D printing