基于生物质制备多孔碳的电化学储能研究

近年来,大量化石燃料的使用改变了全球气候,加剧了温室效应并且产生了严重的热污染.能源枯竭和环境污染问题迫在眉睫,为实现生态环境的可持续发展,人们研究和开发了各种新型的储能材料和器件.超级电容器是最近几年发展迅速的一种新型储能装置,典型特点是储能和快速充放电.因为生物质绿色无污染、资源丰富和可再生,另外,生物质氮自掺杂炭材料因为孔隙发达、孔隙可调、耐酸碱、比表面积大,故可作为制备电极材料碳源的最优选择.本文分别以石榴籽和化妆棉两种生物质作为碳源,利用高温热解法来制备生物质氮自掺杂炭材料电极,并测其电化学性能.经过电化学测试得出,在1 A/g的电流密度下,石榴籽与KOH的质量比为3:1时比电容最大,约为295 F·g-1,同样电流密度下,化妆棉与KOH质量比为3:1时比电容最大,约为225 F·g-1.     

A Novel LaAlO3 Perovskite with Large Surface Area Supported Ni-Based Catalyst for Methane Dry Reforming

Catalysis Letters - In this paper, the LaAlO3 perovskite with large specific surface area and abundant surface oxygen vacancies is prepared by the hard template method, on which Ni metal...     

The Effect of a Polymeric Flame Retardant Containing Phosphorus–Sulfur–Silicon and a Caged Group on Unsaturated Polyester Resin

Journal of Inorganic and Organometallic Polymers and Materials - Currently, the issue of natural flammability of unsaturated polyester resin (UPR) severely restrains its application. In this study,...     

Effect of solid loading and carbon additive on microstructure and mechanical properties of 3D-printed SiC ceramic

3D-printed SiC ceramics were prepared by direct ink writing and solid-phase sintering. The effects of sintering temperature, solid loading, and carbon additive on microstructures and mechanical properties of 3D-printed SiC parts were investigated. It was found that the sintering temperature affected the evolution of the microstructure and mechanical properties of the sintered SiC parts. A high solid loading promoted the densification and mechanical properties of the sintered SiC parts. However, the solid loading exceeded 40 vol.%, which decreased the density and mechanical properties of the samples. The carbon additives could improve the densification of the SiC parts and enhance their mechanical properties. When the sucrose content increased from 0 to 8 wt.%, the open porosity of the SiC part decreased from 26.12% to 3.15%, whereas the flexural strength increased 2.19 times. Using the optimized components and process parameters, the high-performance 3D-printed SiC parts were achieved.     

Preparation and toughening mechanism of Mo2NiB2-based cermets with SiC whiskers

Mo₂NiB₂ is a kind of cermet with excellent mechanical properties, stable chemical properties, and excellent corrosion resistance and is often used in wear-resistant application fields, such as injection molding machine parts, can making tools and hot copper extruding dies. The brittleness of Mo₂NiB₂-based cermets limits their wide application. Mo₂NiB₂-based cermets were prepared by the vacuum sintering method, the effect of SiC whiskers (SiCw) on the microstructure and mechanical properties of cermets was investigated, and the toughening mechanism of SiCw on cermets was further discussed. The results indicate that with increasing SiCw content, the indentation fracture toughness (K_IC), transverse fracture strength (TRS), and Vickers hardness (HV) of the cermets first increase and then decrease. The HV, TRS, and indentation fracture toughness of Mo₂NiB₂-based cermets with 0.5 wt% SiCw are 1 113 HV, 1 620 MPa, and 27.97 MPa·m^1/2, respectively, which are 16.8%, 22.7%, and 25% higher than those without SiCw. In the sliding friction tests, Mo₂NiB₂-based cermets with 0.5 wt% SiCw have the smallest friction coefficient, low wear rate, and high wear resistance. SEM observation and analysis of the crack path and fracture surface showed that the toughening mechanism is whisker bridging, crack deflection, microcrack toughening, and whisker pull-out. The results indicate that the addition of 0.5 wt% SiCw can effectively improve the mechanical properties of Mo₂NiB₂-based cermets and further expand the application space of Mo₂NiB₂-based cermets.     

Numerical Investigation of Bottom Grille for Improving Large-Size Silicon Quality in Directional Solidification Process

Silicon - 2D global transient numerical model based on a new large-size ALD-G7 (G7) crystalline silicon ingot furnace is established and experimentally verified. A new pyramid-shaped bottom grille...     

Design and Numerical Optimization of Gas Guidance System in Casting Silicon Furnace by the Orthogonal Experiment

Silicon - 3D global simulations were performed to investigate the gas flow and impurities transport in casting silicon furnace under the influence of a unique designed spray-type gas guidance...     

As-NaOH-ClO~-体系脱砷试验

提出了在As-NaOH-ClO体系脱砷的方法,并以含砷镍烟灰为原料,系统研究了该体系下的脱砷效果。结果表明:在液固比L/S=10、NaClO浓度4.1%、NaOH浓度3%、反应温度50℃、反应时间1h的最优条件下,砷脱除率达到75%以上,镍损失率小于0.03%,可实现砷的无害化处理和金属镍的回收。     

Effect of Deep Cryogenic Treatment on Wear and Corrosion Resistance of an Al–Zn–Mg–Cu Alloy

Russian Journal of Non-Ferrous Metals - The 7075 aluminum alloy was subjected to deep cryogenic treatment (DCT) at –196°C with liquid nitrogen for different hours. The wear and corrosion...     

Adaptive control of a vehicle-seat-human coupled model using quasi-zero-stiffness vibration isolator as seat suspension

We propose the quasi-zero-stiffness (QZS) vibration isolator as seat suspension to improve vehicle vibration isolation performance. The QZS vibration isolator is composed of vertical spring and two symmetric negative stiffness structures used as stiffness correctors. A vehicle-seat-human coupled model considering the QZS vibration isolator is established as a three degree-of-freedom (DOF) model; it is composed of a quarter car model and a simplified 1 DOF model combined vehicle seat and human body. This model considers the changing mass of the passengers and sets the total mass of the vehicle seat and human body as an uncertain parameter, which investigates the overload and unload conditions in practical engineering. To further improve the vehicle ride comfort, a constrained adaptive backstepping controller law based on the barrier Lyapunov function (BLF) is presented. The dynamic characteristic of the active vehicle-seathuman coupled model under shock excitation was analyzed using numerical method. The results show that the designed controller law can isolate the shock excitation transmitted from the road to the passengers effectively, and both the vehicle and seat suspension strokes remain in the allowed stroke range.