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An improved laser flash method for thermal conductivity measurement of molten salts

Progress in Natural science:Materials International 2024年第2期34卷 345-353页

作者： Shiyan Dong Mingzhen Zhang Kaiyuan Jin Ronggui Yang State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology

Thermal conductivity measurement of high-temperature heat transfer fluids provides a crucial basis for designing utility-scale thermal systems. Molten salts are promising heat transfer and thermal storage fluids in hightemperature thermal energy storage systems, while the molten salt thermal conductivity obtained in existing studies exhibits large deviations due to the high experimental complexity and unstandardized test procedures. In this work, we improve the conventional laser flash analysis method by proposing a theoretical heat transfer model for multi-layer heat conduction and providing a near-optimal molten salt container design. With water as a test sample, the relative error of thermal conductivity measurement using the improved method is 6.3%. The thermal conductivity of Solar Salt from 250 to 400°C, and of Hitec Salt from 160 to 250°C are measured and compared with the previous work. Both results show that the thermal conductivity increases with the temperature *** work will promote the technology standardization for accurately acquiring the thermal conductivity of molten salts or other similar high-temperature heat transfer fluids.

关键词： Laser flash analysis Thermal conductivity Thermal energy storage Molten salt Multi-layer heat conduction

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Optimization of mechanical and safety properties by designing interface characteristics within energetic composites

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Defence technology（防务技术） 2024年第12期42卷 59-72页

作者： Guijun Wang Yanqing Wu Kun Yang Quanzhi Xia Fenglei Huang State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China

The interfacial structure has an important effect on the mechanical properties and safety of the energetic *** this work,a mesostructure model reflecting the real internal structure of PBX is established through image digital modeling and vectorization processing *** microscopic molecular structure model of PBX is constructed by molecular dynamics,and the interface bonding energy is calculated and transferred to the mesostructure *** simulations are used to study the influence of the interface roughness on the dynamic compression and impact ignition response of PBX,and to regulate and optimize the mechanical properties and safety of the explosive to obtain the optimal design of the surface roughness of the explosive *** results show that the critical hot spot density of PBX ignition under impact loading is 0.68 mm^(-2).The improvement of crystal surface roughness can improve the mechanical properties of materials,but at the same time it can improve the impact ignition sensitivity and reduce the safety of *** optimal friction coefficient range for the crystal surface that satisfies both the mechanical properties and safety of PBX is *** work can provide a reference basis for the formulation design and production processing of energetic materials.

关键词： Polymer-bonded explosives Interface roughness Mechanical properties Hot spot Mesostructure optimization

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Kinetics insights into size effects of carbon nanotubes'growth and their supported platinum catalysts for 4,6-dinitroresorcinol hydrogenation

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Chinese Journal of Chemical Engineering 2024年第8期72卷 133-140页

作者： Yan Zhang Xiangxue Zhang Keng Sang Wenyao Chen Gang Qian Jing Zhang Xuezhi Duan Xinggui Zhou Weikang Yuan State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Size effects are a well-documented phenomenon in heterogeneous catalysis,typically attributed to alterations in geometric and electronic *** this study,we investigate the influence of catalyst size in the preparation of carbon nanotube(CNT)and the hydrogenation of 4,6-dinitroresorcinol(DNR)using Fe_(2)O_(3)and Pt catalysts,*** Fe_(2)O_(3)/Al_(2)O_(3)catalysts were synthesized for CNT growth through catalytic chemical vapor *** findings reveal a significant influence of Fe_(2)O_(3)nanoparticle size on the structure and yield of ***,CNT produced with Fe_(2)O_(3)/Al_(2)O_(3)containing 28%(mass)Fe loading exhibits abundant surface defects,an increased area for metal-particle immobilization,and a high carbon *** makes it a promising candidate for DNR *** this catalyst support,we further investigate the size effects of Pt nanoparticles on DNR *** Pt catalysts demonstrate a preference for 4,6-diaminoresorcinol generation at(100)sites,whereas smaller Pt catalysts are more susceptible to electronic *** kinetics insights obtained from this study have the potential to pave the way for the development of more efficient catalysts for both CNT synthesis and DNR hydrogenation.

关键词： Kinetics Size effects Catalytic hydrogenation Active site

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Preparation of Si_(3)N_(4)–TiN–SiC composite by partial substitution of Ti–Si–Fe alloy for Si under N_(2)atmosphere

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Journal of Iron and Steel Research International 2024年第12期31卷 3048-3057页

作者： Lu-yan Yao Jin-hua Zhang Bing-qiang Han Yue-e Ni Chang-ming Ke The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina

Si_(3)N_(4)–TiN–SiC composites were prepared by partial substitution of the Ti–Si–Fe alloy extracted from high-titanium blast furnace slag for Si under nitrogen *** nitridation,microstructure and mechanical properties of the composites were investigated in *** results show that Ti–Si–Fe alloy facilitated the nitridation of Si and full nitridation of Si was achieved in the compacts with 3.6–5.4 wt.%Ti–Si–Fe alloy additive,and thus,densification and mechanical performances of the composites were improved *** of microcracks induced by the volume expansions accompanying with the conversion of Ti_(5)Si_(3)and TiSi_(2)to nitrides at 950–1050℃built new N_(2)(g)transport channels in the *** the following up nitridation process,adequate N_(2)(g)was transported through these channels into the compacts to fundamentally enhance contact of N_(2)with Si,facilitate and ensure the complete nitridation of internal ***,the Ti–Si–Fe–Mn–N eutectic liquid played an important role in the formation of bothα-andβ-Si_(3)N_(4),and the Fe in the Ti–Si–Fe alloy was of great importance for the formation of fibrous Si_(3)N_(4)by the reaction between SiO(g)and N_(2)(g).

关键词： Si_(3)N_(4)–TiN–SiC composite Ti–Si–Fe alloy Microcrack Full nitridation Eutectic liquid

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Influence of in situ formed spinel in bonding phase on mechanical properties and air permeability of magnesia-chrome porous purging materials

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Journal of Iron and Steel Research International 2024年第6期31卷 1459-1472页

作者： Yi An Hao Liu Zhou-fu Wang Yan Ma Xi-tang Wang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Magnesia-chrome porous purging plugs are crucial functional components to remove inclusions and stabilize the flow field during iron and steel ***,practical applications of magnesia-chrome porous purging materials are stil hampered by the poor scouring resistance to molten steel and unstable air permeability owing to their low mechanical properties and uncontrollable pore ***,the particle-packing type magnesiachrome porous purging materials reinforced by in situ formed spinel were prepared using fused magnesia-chrome particles and Al powders as major raw *** results show that in situ formed spinel solid solutions in bonding phase led to the decreased median pore size and increased pore surface fractal dimension from the reactions between Al powders and magnesia-chrome particles and along with high-temperature sintering,bonding between magnesia-chrome particles and the resultant mechanical properties of materials were greatly ***,the results of air permeability tests and polynomial ftting indicated that the formation of spinel solid solutions was the main contributing factor for controllable air permeability,and pressure drop of porous purging materials was positively correlated with surface fractal dimension of ***,the as-prepared porous purging materials added with 6 wt.%Al powders obtained the maximum cold crushing strength(54.2 MPa)and hot modulus of rupture(12.9 MPa)with median pore size of 24.06μm and ftting non-Darcian permeability coefficient of 0.97×10^(-6)m.

关键词： Magnesia Chrome porous purging material Metallic Al-Spinel Mechanical strength Air permeability

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Early warning method for thermal runaway of lithium-ion batteries under thermal abuse condition based on online electrochemical impedance monitoring

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Journal of Energy Chemistry 2024年第5期92卷 74-86页

作者： Yuxuan Li Lihua Jiang Ningjie Zhang Zesen Wei Wenxin Mei Qiangling Duan Jinhua Sun Qingsong Wang State Key Laboratory of Fire Science University of Science and Technology of ChinaAnhui 230026HefeiChin

Early warning of thermal runaway(TR)of lithium-ion batteries(LIBs)is a significant challenge in current application *** and effective TR early warning technology is urgently required considering the current fire safety situation of *** this work,we report an early warning method of TR with online electrochemical impedance spectroscopy(EIS)monitoring,which overcomes the shortcomings of warning methods based on traditional signals such as temperature,gas,and pressure with obvious delay and high *** in-situ data acquisition through accelerating rate calorimeter(ARC)-EIS test,the crucial features of TR were extracted using the RReliefF *** mechanisms corresponding to the features at specific frequencies were ***,a three-level warning strategy for single battery,series module,and parallel module was formulated,which can successfully send out an early warning signal ahead of the self-heating temperature of battery under thermal abuse *** technology can provide a reliable basis for the timely intervention of battery thermal management and fire protection systems and is expected to be applied to electric vehicles and energy storage devices to realize early warning and improve battery safety.

关键词： Online EIS measurement Lithium-ion batterysafety Multistage thermal runaway early warning Sensitivityanalysis

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Fabrication and properties of lightweight zirconia with fine closed porosity

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Journal of Iron and Steel Research International 2024年第6期31卷 1449-1458页

作者： Yi-bo Zhang Hua-zhi Gu Lv-ping Fu Ao Huang Mei-je Zhang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Lightweight refractory materials with thermal insulation properties and erosion resistance are advantageous for hightemperature *** zirconia refractories were prepared using starch as a pore-forming agent,basic magnesium carbonate as a stabilizer,and nano-zirconia as an *** effects of the nano-zirconia content on the pore and thermal insulation properties of the lightweight zirconia refractories were investigated based on the porosity,phase composition,microstructure,and thermal ***-zirconia was shown to have a high surface energy,and its addition effectively increased the driving force for sintering,reduced the sintering temperature,and promoted the sintering reaction,thereby reducing the apparent porosity and improving the density of the prepared *** to the superplasticity of nano-zirconia,the surface stress caused plastic deformation between particles,which increased the migration rate of grain boundaries and trapped more gas inside the material before it diffused to the surface,thereby enhancing the closed porosity of the *** presence of closed pores could extend the thermal conduction path,decrease the conduction rate,and hinder the conduction effect to effectively reduce the thermal conductivity of the *** a nano-zirconia content of 0.75 wt.%,the prepared lightweight zirconia had the highest closed porosity and the lowest thermal *** apparent porosity,closed porosity,and total porosity of the material were 2.8%,7.0%,and 9.8%,respectively,and the thermal conductivity at 800℃was 1.37 W m^(-1)k^(-1).

关键词： Sintering Nano-zirconia Closed pore:Thermal conductivity Refractory material

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Effects of nano-metal oxide additives on ignition and combustion properties of MICs-boron rich fuels

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Defence technology（防务技术） 2024年第9期39卷 157-167页

作者： Liang Hu Danyang Liu Kun Yang Jianying Lu Chao Shi Jianyu Wang Xinhang Liu Lang Chen State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing100081China

Boron has been considered a promising powdered metal fuel for enhancing composite propellants'energy output due to its high energy ***,the high ignition temperature and low combustion efficiency limit the application of boron powder due to the high boiling point of the boron oxide *** research is ongoing to overcome these shortcomings,and one potential approach is to introduce a small quantity of metal oxide additives to promote the reaction of *** study prepared boron-rich fuels with 10 wt%of eight nano-metal oxide additives by mechanical ball *** effect of metal oxides on the thermo-oxidation,ignition,and combustion properties of boron powder was comprehensively studied by the thermogravimetric analysis(TG),the electrically heated filament setup(T-jump),and the laser-induced combustion *** experiments at 5 K/min found that Bi_(2)O_(3),MoO_(3),TiO_(2),Fe_(2)O_(3),and CuO can promote thermo-oxidation of *** to pure boron,Tonsetcan be reduced from 569℃to a minimum of 449℃(B/Bi_(2)O_(3)).Infrared temperature measurement in T-jump tests showed that when heated by an electric heating wire at rates from 1000 K/s to 25000 K/s,the ignition temperatures of B/Bi_(2)O_(3) are the lowest,even lower than the melting point of boron *** images and SEM for the products further showed that the high heating rate is beneficial to the rapid reaction of boron powder in the single-particle combustion ***(B/Bi_(2)O_(3),B/MoO_(3),and B/CuO)were mixed with the oxidant AP and ignited by laser to study the combustion *** results showed that B/CuO/AP has the largest flame area,the highest BO_(2) characteristic spectral intensity,and the largest burn rate for powder *** combine the advantages of CuO and Bi_(2)O_(3),binary metal oxide(CBO,mass ratio of 3:1)was prepared and the test results showed that CBO can very well improve both ignition and combustion properties of *** B/CBO/AP has the h

关键词： Boron-rich fuel Mechanical ball milling Electrically heated filament Laser-induced combustion

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Empirical model of concrete block fragment behavior under explosion loads

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science China(Technological sciences) 2024年第8期67卷 2515-2529页

作者： YANG Shuai NING JianGuo REN HuiLan XU XiangZhao State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China

Concrete structures undergo integral fragmentation under explosion loads. The fragmentation degree and particle-size distribution of concrete blocks under explosion loads must be considered during mining to ensure safety. In this study, the impulse is calculated based on the relationship between overpressure and time, and the impact energy of the explosion wave is obtained based on blast theory. Subsequently, the Mohr-Coulomb shear strength fracture criterion is introduced to determine the ultimate shear stress of the concrete materials, and an empirical model that can effectively calculate the energy consumption of concrete blocks under explosion loads is established. Furthermore, concrete fragments with different particle sizes under explosion scenarios are quantitatively predicted with the principle of energy conservation. Finally, explosion tests with different top standoff distances are conducted, and the concrete fragments after the explosion tests are recovered, sieved, weighed, and counted to obtain experimental data. The effectiveness of the fragment empirical model is verified by comparing the model calculation results with the experimental data. The proposed model can be used as a reference for civil blasting, protective engineering design, and explosion-damage assessment.

关键词： concrete structures explosion loads fragment behavior empirical model

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High-temperature wetting behavior between slag and refractory

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Journal of Iron and Steel Research International 2024年第6期31卷 1304-1319页

作者： Yong-xin Wang Ya-ge Li Ya-bo Gao Zhong Huang Hai-jun Zhang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Slag corrosion is one of the main factors of the damage of refractory,and its primary manifestations involve the melting of refractory in slag and the slag penetration into refractory,both of which are highly related to the wetting behavior between slag and *** high-temperature wettability could be characterized by parameters including the surface tension,adhesion work,and spreading coefficient of the slag on refractory surface,and it could be suppressed by altering the slag/refractory interface,thus resulting in an improved anti-corrosion *** this,the key knowledges of the slag corrosion,theory of wetting behavior and test of high-temperature contact angle were firstly ***,the major factors influencing the high-temperature slag wetting behavior were discussed based on the aspects of slag composition,refractory composition,and surface ***,the future research direction was proposed in this field.

关键词： High-temperature wetting Refractory Slag corrosion Surface tension

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