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52.
Based on multiphase field conception and integrated with the idea of vectorvalued phase field, a phase field model for typical allotropic transformation of solid
solution is proposed. The model takes the non-uniform distribution of grain boundaries of
parent phase and crystal orientation into account in proper way, as being illustrated by the
simulation of austenite to ferrite transformation in low carbon steel. It is found that the
misorientation dependent grain boundary mobility shows strong influence on the
formation of ferrite morphology comparing with the weak effect exerted by
misorientation dependent grain boundary energy. The evolution of various types of grain
boundaries are quantitatively characterized in terms of its respective grain boundary
energy dissipation. The simulated ferrite fraction agrees well with the expectation from
phase diagram, which verifies this model. 相似文献
53.
Atomic Modulation Triggering Improved Performance of MoO3 Nanobelts for Fiber‐Shaped Supercapacitors
Si Liu Cuixia Xu Hui Yang Guangsheng Qian Shugui Hua Jie Liu Xusheng Zheng Xihong Lu 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(6)
Asymmetric supercapacitors (ASCs) are emerging as a new class of energy storage devices that could potentially meet the increasing power and energy demand for next‐generation portable and flexible electronics. Yet, the energy density of ASC is severely limited by the low capacitance of the anode side, which commonly uses the carbon‐based nanomaterials. Here, the demonstration of sulfur‐doped MoO3?x nanobelts (denoted as S‐MoO3?x) as the anode for high‐performance fiber‐shaped ASC are reported. The Mo sites in MoO3 are intentionally modulated at the atomic level through sulfur doping, where sulfur could be introduced into the MoO6 octahedron to intrinsically tune the covalency character of bonds around Mo sites and thus boost the charge storage kinetics of S‐MoO3?x. Moreover, the oxygen defects are occurring along with sulfur‐doping in MoO3, enabling efficient electron transport. As expected, the fiber‐shaped S‐MoO3?x achieves outstanding capacitance with good rate capability and long cycling life. More impressively, the fiber‐shaped ASC based on S‐MoO3?x anode delivers extremely high volumetric capacitance of 6.19 F cm?3 at 0.5 mA cm?1, which makes it promising as one of the most attractive candidates of anode materials for high‐performance fiber‐shaped ASCs. 相似文献
54.
Hua Zhao Michael S Franklin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2020,95(9):2301-2310
Coal is the most abundant fossil fuel. Direct combustion of low- and medium-rank coals causes alarming environmental impacts. Therefore, it is crucial for coal to undergo pretreatments before its efficient utilization [such as coal to liquid (CTL) processes]. Conventional pretreatment methods suffer from several limitations including the use of volatile organic solvents, environmental hazards, strong reaction conditions (e.g. high temperature and pressure), consumption of large quantities of nonrecoverable chemicals (e.g. bases used in aqueous alkaline digestion), or being only effective for specific coals. On the other hand, coal pretreatment by nonvolatile ionic liquids (ILs) could lead to partial coal dissolution/swelling and structure disruption, which is a critical step before coal liquefaction, hydrogenation, pyrolysis or the inhibition of oxidation/combustion. In addition, ILs are suitable solvents for extracting sulfur compounds from coal, asphaltenes from Direct Coal Liquefaction Residues (DCLR) and phenolic compounds from coal tar. This review will discuss these aspects of coal pretreatments by ILs, and identify how ILs could lead to a cleaner and more efficient utilization of coal resources. © 2020 Society of Chemical Industry 相似文献
55.
Metals and Materials International - A model based on inter-diffusion theory was established to predict growth kinetics of the intermetallic compounds (IMCs) formed in roll bonded Al/Cu sheets... 相似文献
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59.
以2,6,8,12-四乙酰基-2,4,6,8,10,12-六氮杂四环-[5,5,0,03,11,05,9]十二烷(TAIW)为原料,采用N2O5/HNO3为硝化剂硝解TAIW制备六硝基六氮杂异伍茲烷(CL-20)。通过系统研究N2O5/HNO3硝解TAIW的加料方式、温度、料比、反应时间、稀释用水量等因素对反应收率和纯度的影响,找出了最佳反应条件:反应温度60~80℃,反应时间7h,m(TAIW)∶m(N2O5)∶V(HNO3)=3g∶4g∶15mL,后处理时稀释用水量20mL,CL-20收率为82.34%,纯度为98.29%。当以质量分数10%的CF3SO3H/树脂为催化剂时,收率提高至87.35%,纯度基本不变,且催化剂的回收率达到99.15%。该方法避免硫酸的使用,减轻了废酸污染,具有较强的工业化应用前景。 相似文献
60.
煤气化废水的特点是温度高、硬度高、NH3-N高、有机物含量相对不足。针对这些特点引起的运行不稳定,逐一提出解决方案,并形成一套完整的针对煤气化废水的处理工艺。 相似文献