The carbon-based metal-free materials as catalysts(named as carbocatalysts) have been attracting tremendous attentions in electric-,solar-and thermal-driven reactions nowadays.Compared to electrocatalysis and photocat...The carbon-based metal-free materials as catalysts(named as carbocatalysts) have been attracting tremendous attentions in electric-,solar-and thermal-driven reactions nowadays.Compared to electrocatalysis and photocatalysis,the thermal-driven catalysis(thermocatalysis) including liquid phase and gas phase reactions involves wider scope and is relatively easy to realize practical large-scale applications.Over the past several years,some striking achievements on the design of new carbon-based metal-free materials with well-defined structures and heteroatom groups as well as the revelation of new reaction mechanisms and active sites in thermocatalysis have been obtained.However,comparative discussions regarding these recent achievements have been rarely highlighted.In this review,we systematically summarize and discuss six kinds of carbocatalysts and their applications in thermocatalysis.These materials include typical oxygen-attached carbon,surface modified carbon(graft with certain organic compounds),mono-doped carbon,co-doped carbon,carbon nitride and materials with carbon as dopant.Some new reaction processes as well as the related reaction mechanisms,active sites and intermediates are reviewed critically.Moreover,an outlook on the in-depth investigation of the metalfree carbocatalysis in the future is provided.展开更多
为研究长距离公路隧道电力电缆区在夏季机械通风条件下仍然存在的高温环境问题,以上海市G40长距离跨江隧道为研究对象,采用CFD模拟方法,探究电缆发热量、室外环境温度和通风量对电力电缆区温度场分布的影响规律,并提出适用于该隧道结构...为研究长距离公路隧道电力电缆区在夏季机械通风条件下仍然存在的高温环境问题,以上海市G40长距离跨江隧道为研究对象,采用CFD模拟方法,探究电缆发热量、室外环境温度和通风量对电力电缆区温度场分布的影响规律,并提出适用于该隧道结构的温度预测关联式,用于解决工程实践中面临的“高温区域覆盖范围如何界定”以及“下游温度超标临界条件如何判定”等关键问题。结果表明:1)在夏季机械排风工况下,电力电缆区的空气温度沿着隧道纵向呈现非线性增长趋势,表明气流驱动的热迁移现象显著;2)电缆发热量对隧道进排风温差呈现非线性增长特征,当电缆长期高负载运行时,电缆区排风温度将超过标准规定的安全阈值(≤40℃);3)降低隧道入口温度虽可减少排风温度,但会导致进排风温差扩大超出规范限值(≤10℃);4)通风量每增大87.81 m 3/s(即换气次数增大2次/h)可使排风温度降低约3.57℃,但过高的通风量会导致风机功耗激增,因此需要进一步研究通风策略以平衡降温效果与风机能耗之间的关系。展开更多
The paper adopts an f-plane quasi-geostrophic inertial model without linearization to investigate the perturbation temperature, boundary jet and upwelling (downwelling) in an idealized rectangular basin, under the con...The paper adopts an f-plane quasi-geostrophic inertial model without linearization to investigate the perturbation temperature, boundary jet and upwelling (downwelling) in an idealized rectangular basin, under the consideration of west side friction layer and heat conservation. There is net heat input on the upper surface and equal quality heat dissipation on the west boundary, and without heat exchange on other boundaries, then the heat is conservation in the whole basin. Results show that there is thermal front due to denseness of the perturbation temperature in the west side boundary, the perturbation pressure and flow field are reversal on the upper layer and bottom layer. On the bottom layer, the west coastal current is northward, and the maximum perturbation pressure center is on the west, however, on the upper layer, the east coastal current is southward, and the maximum perturbation pressure center is on the east. There is strong vertical flow in narrow western boundary layer, and also in the central zone. The effect of different upper thermal forcings is also studied, and it can be concluded that there is always temperature denseness and boundary jet near the west boundary, and the appearance of flow field reversal, but the distribution of vertical flow is rather different.展开更多
基金supported by the Award Program for Fujian Minjiang Scholar Professorship,the National Natural Science Foundation of China(21571035)Chemical Engineering&Technology of Zhejiang Province First-Class Discipline(Taizhou University),Zhejiang Provincial Natural Science Foundation of China(LQ20B060001)Taizhou science and technology planning project(1902gy20)。
文摘The carbon-based metal-free materials as catalysts(named as carbocatalysts) have been attracting tremendous attentions in electric-,solar-and thermal-driven reactions nowadays.Compared to electrocatalysis and photocatalysis,the thermal-driven catalysis(thermocatalysis) including liquid phase and gas phase reactions involves wider scope and is relatively easy to realize practical large-scale applications.Over the past several years,some striking achievements on the design of new carbon-based metal-free materials with well-defined structures and heteroatom groups as well as the revelation of new reaction mechanisms and active sites in thermocatalysis have been obtained.However,comparative discussions regarding these recent achievements have been rarely highlighted.In this review,we systematically summarize and discuss six kinds of carbocatalysts and their applications in thermocatalysis.These materials include typical oxygen-attached carbon,surface modified carbon(graft with certain organic compounds),mono-doped carbon,co-doped carbon,carbon nitride and materials with carbon as dopant.Some new reaction processes as well as the related reaction mechanisms,active sites and intermediates are reviewed critically.Moreover,an outlook on the in-depth investigation of the metalfree carbocatalysis in the future is provided.
文摘为研究长距离公路隧道电力电缆区在夏季机械通风条件下仍然存在的高温环境问题,以上海市G40长距离跨江隧道为研究对象,采用CFD模拟方法,探究电缆发热量、室外环境温度和通风量对电力电缆区温度场分布的影响规律,并提出适用于该隧道结构的温度预测关联式,用于解决工程实践中面临的“高温区域覆盖范围如何界定”以及“下游温度超标临界条件如何判定”等关键问题。结果表明:1)在夏季机械排风工况下,电力电缆区的空气温度沿着隧道纵向呈现非线性增长趋势,表明气流驱动的热迁移现象显著;2)电缆发热量对隧道进排风温差呈现非线性增长特征,当电缆长期高负载运行时,电缆区排风温度将超过标准规定的安全阈值(≤40℃);3)降低隧道入口温度虽可减少排风温度,但会导致进排风温差扩大超出规范限值(≤10℃);4)通风量每增大87.81 m 3/s(即换气次数增大2次/h)可使排风温度降低约3.57℃,但过高的通风量会导致风机功耗激增,因此需要进一步研究通风策略以平衡降温效果与风机能耗之间的关系。
文摘The paper adopts an f-plane quasi-geostrophic inertial model without linearization to investigate the perturbation temperature, boundary jet and upwelling (downwelling) in an idealized rectangular basin, under the consideration of west side friction layer and heat conservation. There is net heat input on the upper surface and equal quality heat dissipation on the west boundary, and without heat exchange on other boundaries, then the heat is conservation in the whole basin. Results show that there is thermal front due to denseness of the perturbation temperature in the west side boundary, the perturbation pressure and flow field are reversal on the upper layer and bottom layer. On the bottom layer, the west coastal current is northward, and the maximum perturbation pressure center is on the west, however, on the upper layer, the east coastal current is southward, and the maximum perturbation pressure center is on the east. There is strong vertical flow in narrow western boundary layer, and also in the central zone. The effect of different upper thermal forcings is also studied, and it can be concluded that there is always temperature denseness and boundary jet near the west boundary, and the appearance of flow field reversal, but the distribution of vertical flow is rather different.
