History of the tether concept and tether missions: a review

This paper introduces history of space tethers, including tether concepts and tether missions, and attempts to provide a source of references for historical understanding of space tethers. Several concepts of space tethers since the original concept has been conceived are listed in the literature, as well as a summary of interesting applications, and a research of space tethers is given. With the aim of implementing scientific experiments in aerospace, several space tether missions which have been delivered for aerospace application are introduced in the literature.</jats:p

PPRT : a hybrid point and polygon ray tracer for meshes

In this thesis, we introduce a simple but efficient hybrid ray tracing system for triangular meshes. Different from the existing pure point or polygon ray tracing systems, the traced models are represented and rendered by both points and triangles. We accept triangle meshes as input, and hierarchically build up a multi-resolution tree structure with intermediate nodes as points and leaf nodes as triangles. The trade-off between rendering portions of a model with points or with triangles is made automatically based on the screen contribution of each node. Our system balances the quantity of a mesh model with its quality, reflects the level-of-detail representation and selection, maintains the simplicity of the point primitive, and allows for producing high quality ray traced images with more advanced illumination models and global illumination

Valley physics in non-Hermitian artificial acoustic boron nitride

The valley can serve as a new degree of freedom in the manipulation of particles or waves in condensed matter physics, whereas systems containing combinations of gain and loss elements constitute rich building units that can mimic non-Hermitian properties. By introducing gain and loss in artificial acoustic boron nitride, we show that the acoustic valley states and the valley-projected edge states display exotic behaviors in that they sustain either attenuated or amplified wave propagation. Our findings show how non-Hermiticity introduces a mechanism in tuning topological protected valley transports, which may have significance in advanced wave control for sensing and communication applications.J. C. acknowledges the support from the European Research Council (ERC) through the Starting Grant No. 714577 PHONOMETA and from the MINECO through a Ramón y Cajal grant (Grant No. RYC-2015-17156). This work was supported by the National Basic Research Program of China (Grant No. 2015CB755500); National Natural Science Foundation of China (Grants No. 11774275, No. 11674250, No. 11534013, and 11547310); Natural Science Foundation of Hubei Province (Grant No. 2017CFA042)

Tris[2-(1H-imidazol-2-yl)imidazol-1-ido]cobalt(III)

In the title compound, [Co(C6H5N4)3], the CoIII atom adopts a distorted octa­hedral CoN6 coordination geometry, arising from three N,N′-bidentate deprotonated 2,2′-biimidazole ligands. The dihedral angles between the five-membered rings of the ligands are 4.1 (2), 9.4 (2) and 10.5 (2)°. In the crystal, mol­ecules are linked by N—H⋯N hydrogen bonds, generating a layered network lying in (11)

Preparation of an N–S dual-doped black fungus porous carbon matrix and its application in high-performance Li–S batteries

A nitrogen–sulfur dual-doped black fungus porous carbon (NS-FPC) matrix was prepared with natural black fungus as the carbon source and cysteine as the nitrogen–sulfur source. A black fungus-based solution was obtained by hydrothermal treatment. After further carbonization activation and combination with sulfur processing, the NS-FPC/S positive electrode materials were prepared. The uniform recombination of biomass carbon provides an efficient conductive framework for sulfur. The porous structure is conducive to the transport of electrolytes. Heteroatom doping can provide a more active site. The structure and composition analyses of the materials were carried out using X-ray diffraction (XRD). The electronic binding energy and bonding state were analyzed by X-ray photoelectron spectroscopy (XPS). The morphology was observed by scanning electron microscopy and transmission electron microscopy. The specific surface area and pore size distribution were analyzed using an N2 adsorption–desorption experiment. Sulfur loading was determined through thermogravimetric analysis. The electrochemical performance of NS-FPC/S in Li–S batteries was systematically investigated. The result shows that the NS-FPC/S electrode maintains more than 1,000 mAh g-1 reversible capacity after 100 cycles at 0.2 C current density, with a capacity retention of 85%. The cycle and rate performance are both considerably superior to those of traditional activated carbon materials

Preparation of hydrophobic fabrics and effect of fluorine monomers on surface properties

Preparation of hydrophobic cotton fabric based on the self-assembly method was proposed. The cotton fabric was modified with 3-(methacryloyloxy)propyltrimethoxysilane and grafted with trifluoroethyl methacrylate and dodecafluoroheptyl methacrylate through free radical polymerization reaction. The objective of this research work was to investigate the effect of fluorine monomer with different chemical structure deposited on cotton fabric on the hydrophobic property. The chemical structure, surface topography, and surface wettability of the fabrics were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and water contact angle experiments, respectively. The results showed that the as-prepared fabrics exhibited water contact angle of above 140°. It was noticed that the fluorocarbon chain length of a modifier and its chemical structure could strongly affect the hydrophobic property of the modified fabrics, and the increase in fluorine atoms caused an increase in the water contact angle valuesPostprint (published version