Solar interfacial evaporation is a green, environmental-friendly, energy-saving technology for clean water production. Designing a solar evaporator with a special structure is a feasible way to enhance the effect of light and heat. However, low efficiency, high cost and complicated manufacturing of solar evaporator are still its key problems. Biomass-based materials, with their unique natural structure, good environmental friendliness and low cost, have attracted extensive research interest as solar energy absorbing materials. In this paper, the cheap biomass sorghum straw (SS) is used as the material, and the dehydrated carbonation property of sulfuric acid is used to make the top of sorghum straw form a carbonation layer, and this carbonation layer forms a special –bowl-like structure, which increases the reflection of the incident light and the capture of the light, so that the sorghum straw solar energy evaporator's light absorption rate is more than 90 %, the evaporation rate is as high as 1.96 kg m −2 h −1 under one solar radiation, and the evaporation efficiency is 81.8 %. Notably, CSS demonstrated remarkable cyclic stability, along with excellent desalination and purification performances. This research offers a practical approach for the efficient utilization of sorghum straw, thereby holding substantial research significance and practical application potential.
Yan-Peng Ni,Wan-Shou Wu,Lin Chen,Xi Zhao,Zi-Hao Qin,Xiu-Li Wang,Yu-Zhong Wang
To systematically study how the H-bonding interaction affect the flame retardancy and anti-dripping behavior of poly(ethylene terephthalate) (PET), two series of PET-based copolyesters are prepared by introducing two benzimidazole monomers with similar structure. One (2-(4-methoxycarbonyl-phenyl)-1H-benzimidazole-5-carboxylic acid methyl ester, PBM) contains H-bonding donor, the other (2-(4-methoxycarbonyl-phenyl)-1-methylbenzimidazole-5-carboxylic acid methyl ester, PNM) weeds out the H-bonding donor by replacing NH group with N CH 3 . The dynamic rheological behavior, fire resistance and fire-retardant mechanism of the PET- co -PBMs and PET- co -PNMs are contrastively investigated. PET- co -PNMs have flow behaviors similar to neat PET. While, for PET- co -PBMs, the movements of the molecular chains are restricted due to the H-bonding interaction, leading to higher melt viscosity, which is conducive to the anti-dripping property. It can be proved that benzimidazole groups promote the carbonization of substrates to form more stable charred layers in combustion, showing an obvious barrier action in condensed phase. Unfortunately, the enhancement of carbonization alone is not enough to inhibit the dripping behavior satisfactorily, and PET- co -PNMs fail to pass UL-94 V-0 rating. While, PET- co -PBMs exhibit better self-extinguishing and anti-dripping performances benefiting from strong H-bonding interactions. The revealed effects of H-bonding interactions on the fire resistance and anti-dripping behavior of polymers will guide further design of flame retardants.
He Yan,Yuan Zewei,Song Shuyuan,Gao Xingjun,Deng Wenjuan
Photocatalysis-assisted chemical mechanical polishing, in which the photocatalysis oxidation and silica abrasives polishing are combined, is a novel finishing technique for 4H–SiC wafer. This paper characterizes the effect of pressure and abrasives on the MRR and surface quality and discusses mechanical and chemical interaction based three slurries that resulted in maximum material removal rate (1.18 μm/h) with PCMP slurry. The polished silicon carbide wafer was examined with atomic force microscope, transmission electron microscope and X-ray photoelectron spectroscopy for surface quality and material removal mechanism. The results show that an atomically smooth and flat 4H–SiC (0001) surface (Ra about 0.247 nm) was obtained by PCMP. The interface of crystal and amorphous layer of 4H–SiC wafer was flat without introducing crystallographic subsurface damage, and the atoms and lattice fringes of the crystal layer are arranged in regular order. The existence of a thin silicon oxycarbide layer, which are various forms of functional groups such as Si–C, Si–C–O, Si–O, Si 4 C 4 O 4 , C–O, and C = O, at the interface. And, it also demonstrates that the amorphous layer is composed of oxide layer (4–6 nm) and distorted layer. The silicon carbide surface is mechanically activated, oxidized and mechanically removed in turn, which is the main method of material removal.
危险品化学品经营许可证（带存储）