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Relationship between hydrogenation degree and pyrolysis performance of jet fuel

Chinese Journal of Chemical Engineering 2024年第4期68卷 35-42页

作者： qing liu Tinghao Jia Lun Pan Jijun Zou Xiangwen Zhang Key Laboratory for Green Chemical and Technology School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhejiang Institute of Tianjin University Ningbo 315201China Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China

Understanding the relationship between the chemical composition and pyrolysis performance of endothermic hydrocarbon fuel(EHF) is of great significance for the design and optimization of advanced EHFs. In this work, the effect of deep hydrogenation on the pyrolysis of commercial RP-3 is *** with different hydrogenation degrees were obtained by the partially and completely catalytic hydrogenation and their pyrolysis performances were investigated using an apparatus equipped with an electrically heated tubular reactor. The results show that with the increase of hydrogenation degree, fuel conversion almost remains constant during the pyrolysis process(500-650°C, 4 MPa);however, the heat sink increases slightly, and the anti-coking performance significantly improves, which are highly related to their H/C ratios. Detailed characterisations reveal that the difference of the pyrolysis performance can be ascribed to the content of aromatics and cycloalkanes: the former are prone to initiate secondary reactions to form coking precursors, while the latter could act as the hydrogen donor and release hydrogen, which will terminate the radical propagation reactions and suppress the coke deposition. This work should provide the guidance for upgrading EHFs by modulating the composition of EHFs.

关键词： RP-3 Fuel Pyrolysis Hydrogenation Deposition

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Error modeling and compensating of a novel 6-DOF aeroengine rotor docking equipment

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Chinese Journal of Aeronautics 2022年第6期35卷 312-324页

作者： Tianyi ZHOU Hang GAO Xuanping WANG Lun LI qing liu Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024China AECC Shenyang Liming Aero-engine Co. LtdChina

In the docking process of aeroengine rotor parts,docking accuracy that indicates the gaps between the end faces is strictly required.A key issue is improving docking accuracy using automated docking *** this paper,a systematic study is carried out on the error modeling and compensation of a novel six-degrees-of-freedom(6-DOF)docking equipment for aeroengine ***,a new model for indicating the main indexes of docking accuracy is ***,the error model of a specially designed 6-DOF docking equipment is established based on a modified Denavit Hartenberg method with five ***,two error compensation methods are *** on the above models,a docking accuracy simulation algorithm is proposed using the Monte Carlo ***,verification experiments are *** results show that,for the maximum values and standard deviations of the gaps between the rotor end-faces in the actual and target positions and attitudes,i.e.,main indexes that represent docking accuracy,the deviation rates between the simulation and experimental results are less than20%.The modeling methods have referential *** decline rates of these values are 50–65%when using the two proposed compensation *** compensation methods significantly improve the docking accuracy.

关键词： Accuracy analysis Aeroengine rotor Docking Error compensation Error models Multi-degree-of-freedom structures

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In situ observation of transmission and reflection of dislocations at twin boundary in CoCrNi alloys

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Science China(Technological Sciences) 2021年第2期64卷 407-413页

作者： LIANG YanXiang YANG XiaoFang MING KaiSheng XIANG ShiHua liu qing International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The deformation mechanism of CoCrNi alloy with high density of annealing twins was studied by in situ transmission electron microscopy. Dislocation transmission and reflection at the twin boundary were observed during in situ loading. We characterized these reaction processes by combining TEM, dislocation theory and crystallography of twin. Twin boundary not only strengthens the material by impeding the motion of dislocation, but also acts as dislocation source to produce large of slip bands. These processes generate large of slip bands to accommodate the plastic deformation or strengthening material.

关键词： dislocation transmission reflection TEM CoCrNi alloys

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Predicting the alloying element yield in a ladle furnace using principal component analysis and deep neural network

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International Journal of Minerals,Metallurgy and Materials 2023年第2期30卷 335-344页

作者： Zicheng Xin Jiangshan Zhang Yu Jin Jin Zheng qing liu State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Tangshan Branch Hebei Iron and Steel Co.Ltd.Tangshan 063000China

The composition control of molten steel is one of the main functions in the ladle furnace(LF)refining *** this study,a feasible model was established to predict the alloying element yield using principal component analysis(PCA)and deep neural network(DNN).The PCA was used to eliminate collinearity and reduce the dimension of the input variables,and then the data processed by PCA were used to establish the DNN *** prediction hit ratios for the Si element yield in the error ranges of±1%,±3%,and±5%are 54.0%,93.8%,and98.8%,respectively,whereas those of the Mn element yield in the error ranges of±1%,±2%,and±3%are 77.0%,96.3%,and 99.5%,respectively,in the PCA-DNN *** results demonstrate that the PCA-DNN model performs better than the known models,such as the reference heat method,multiple linear regression,modified backpropagation,and DNN ***,the accurate prediction of the alloying element yield can greatly contribute to realizing a“narrow window”control of composition in molten *** construction of the prediction model for the element yield can also provide a reference for the development of an alloying control model in LF intelligent refining in the modern iron and steel industry.

关键词： ladle furnace element yield principal component analysis deep neural network statistical evaluation

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Effects of metallic microstructures on fatigue fracture of Q345 steel

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Journal of Iron and Steel Research International 2020年第6期27卷 702-709页

作者： Han-qing liu Chun-ming Wang Hong Zhang Zhi-yong Huang qing-yuan Wang Qiang Chen School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065SichuanChina Failure Mechanics and Engineering Disaster Prevention and Mitigation Key Laboratory of Sichuan Province Sichuan UniversityChengdu 610065SichuanChina Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan School of Materials Science and Engineering Jiangxi University of Science and TechnologyGanzhou 341000JiangxiChina

Effects of high-frequency cyclic loading on the banded ferrite-pearlite steel were analyzed through crack initiation and propagation. Interfaces of ferrite and pearlite colony with a small angle deviation from the loading axis were verified to be the most potential sites to fabricate the microcracks caused by the high strain gradient. The initial crack extension inside ferrite grain was driven by shear stress in model II along the direction with a 45° angle to the loading axis. Banded pearlite colony and the high-angle grain boundaries were considered as the dominant factors that promote the fatigue resistance of the material through arousing crack deflection in short crack propagation range and crack branching in long crack propagation range to reduce the crack propagation driving force in the crack tip. P-S-N curves were used to quantify the dispersion of fatigue lifetimes and evaluate the effect of elevated volume content of pearlite colony on the fatigue performance of the material.

关键词： Ferrite-pearlite steel High-cycle fatigue Crack propagation Crack branching High-angle grain boundary P-S-N curve

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Ultra-high voltage 4H-SiC gate turn-off thyristor for low switching time

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Chinese Physics B 2019年第12期28卷 303-310页

作者： qing liu Hong-Bin Pu Xi Wang Xi'an University of Technology Xi'an 710048 China

An ultra-high voltage 4H-silicon carbide(Si C) gate turn-off(GTO) thyristor for low switching time is proposed and analyzed by numerical simulation. It features a double epitaxial p-base in which an extra electrical field is induced to enhance the transportation of the electrons in the thin p-base and reduce recombination. As a result, the turn-on characteristics are improved. What is more, to obtain a low turn-off loss, an alternating p^+/n^+region formed in the backside acts as the anode in the GTO thyristor. Consequently, another path formed by the reverse-biased n^+–p junction accelerates the fast removal of excess electrons during turn-off. This work demonstrates that the turn-on time and turn-off time of the new structure are reduced to 37 ns and 783.1 ns, respectively, under a bus voltage of 8000 V and load current of 100 A/cm^2.

关键词： 4H-SiC gate turn-off(GTO) thyristor turn-on turn-off

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Microstructure and properties of as-cast Zr-2.5Nb-1X(X=Ru,Mo,Ta and Si) alloys for biomedical application

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Rare Metals 2023年第10期42卷 3497-3509页

作者： Xi-Nu Tan Fei-Tao Li Yu-Shun liu Ri-Sheng Qiu qing liu Electron Microscopy Center College of Materials Science and EngineeringChongqing UniversityChongqing400044China International Joint Laboratory for Light Alloys(MOE) College of Materials Science and EngineeringChongqing UniversityChongqing400044China TU Ilmenau Chair Materials for Electrical Engineering and ElectronicsInstitute of Materials Science and Engineering and Institute of Micro-and Nanotechnologies MacroNanoIlmenau98693Germany Department of Mechanical Engineering University of ManitobaWinnipegMBR3T 5V6Canada Key Laboratory for Light-Weight Materials Nanjing Tech UniversityNanjing210009China

The micro structure and properties of as-cast Zr-2.5Nb-1X(X=Ru,Mo,Ta and Si) alloy are screened to explore novel biomedical zirconium alloys for magnetic resonance *** micro structure and phase transformation were characterized using X-ray diffraction(XRD),scanning electron microscope(SEM)and transmission electron microscope(TEM).Hardness test,magnetic detection and electrochemical corrosion measurements are taken to present *** results show that all alloys consist of α-Zr,β-Zr and ω-Zr.α-Zr and β-Zr mainly exist in the form of parallel and intersecting plates,and nanoscale ω-Zr is dispersed in β-Zr ***,blocky ω-Zr with needle-like α-Zr is only found in plate-free blocks of Zr-2.5Nb-1Mo/Ru *** orientation relationship(OR) between α-Zr and ω-Zr follows [1120]_α//[1101]_ω and(0001)_α//([1011]_ω 011)_ω.Combining this OR with the OR between β-Zr and ω-Zr,the transformation relationship between β-Zr/ω-Zr and α-Zr is also ***-2.5Nb-1Ru alloy with high corrosion potential(-0.500 V),low corrosion rate(0.949 μm·year^(-1)) and low magnetic susceptibility(92×10^(-6)) shows great potential to be a novel biomedical implant with magnetic resonance imaging *** on the experimental results,the possible relationship among alloying elements,micro structure and properties has been established in these Zr-2.5Nb-1X alloys.

关键词： Zirconium alloy Microstructure Phase transformation Electrochemical corrosion Magnetic susceptibility

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A weak texture dependence of Hall–Petch relation in a rare-earth containing magnesium alloy

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Journal of Materials Science & Technology 2022年第4期99卷 251-259页

作者： Jing Xu Bo Guan Yunchang Xin Xuedong Wei Guangjie Huang Chenglu liu qing liu International Joint Laboratory for Light Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400030China Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjing 210009China Nuclear Power Institute of China Chengdu 610213China

Hall–Petch slope(k),an important parameter in Hall–Petch relation,describes the efficiency of strengthening effect by grain ***,a highly texture dependent k for Mg alloys is frequently reported,but,in the present study,we report a weak texture dependence of k in a rare-earth containing Mg-2Zn-1Gd plate with two peaks of(0002)poles inclining approximately±30°away from the ND toward the *** there is a strong mechanical anisotropy between tension along the TD and RD,the k for TD-tension(280 MPaμm^(1/2))is quite similar to that for RD-tension(276 MPaμm^(1/2)).Here,RD,TD and ND refer to the rolling direction,transverse direction and normal direction of the plate,*** weak texture dependence of k is well predicted by the compound use of the activation stress difference between neighboring grains(ΔStress)and the geometric compatibility factor(m').By analyzing how the texture affects the values for ΔStress and m,the mechanism for this texture independence of k is ascribed to the activation of a high fraction of additional deformation mode,besides the predominant one for both RD-tension and TD-tension,namely,prismatic slip accompanied by a high fraction of basal slip for RD-tension and basal slip accompanied by a high fraction of prismatic slip for *** will lead to multiple deformation transfer modes and,consequently,the effect of texture on the ease of deformation transfer across grain boundaries is *** a result,there is a similar k for TD-tension and RD-tension.

关键词： Mg alloy Hardening Texture Hall-Petch relation Grain refinement

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Interfacial reaction between oxide inclusion and steel matrix deoxidized by Si and Mn at 1473 K

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Journal of Iron and Steel Research International 2018年第1期25卷 1-8页

作者： Xue-liang Zhang Shu-feng Yang Cheng-song liu Jing-she Li qing liu Gang liu School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083 China Beijing Key Laboratory of Special Melting and Preparationof High-End Metals Beijing 100083 China The State Key Laboratory of Refractories and MetallurgyWuhan University of Science and Technology Wuhan 430081 Hubei China

An improved diffusion couple method was used to simulate the dynamic process of the solid-state reaction at the interface between oxide inclusions and a steel matrix deoxidized by Si and Mn during heat treatment at 1473 K. Experimental results indicated that good contact between the oxide and steel matrix was attained after pre-treatment at 1673 K. In addition, the reaction between the oxide and steel matrix at 1673 K was suppressed, and the effect of this reaction on the diffusion couple experiments at 1473 K was minimized. In the diffusion couple experiments, the diffusion of oxygen from the oxide to the steel matrix resulted in the precipitation of fine oxide particles and a decrease in the Mn content in the steel matrix near the interface after heat treatment at 1473 K. With increasing heat treatment time, the widths of the particle precipitation zone （PPZ） and Mn-depleted zone （MDZ） gradually increased. In addition, the solid-state reaction at the interface between the oxide and steel matrix was intense, and the widths of the PPZ and MDZ increased rapidly during the 0-20 h stage of heat treatment, especially during the 0-5 h stage. The interfacial reaction was retarded, and the rates of width expansion of PPZ and MDZ decreased with increasing heat treatment time.

关键词： Oxide inclusion Diffusion couple Heat treatment Solid-state reaction Interfacial reaction

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不同类型贴布对慢性踝关节不稳患者行走时踝关节运动学的影响

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中国组织工程研究 2025年第14期29卷 2989-2994页

作者：柳青马刚曹建玲张宇熊优何瑞波西安体育学院陕西省西安市710068 中国人民武装警察部队后勤学院卫生勤务系天津市300309

背景:慢性踝关节不稳患者行走时倾向于过度足内翻,这将增加步行周期支撑相踝关节扭伤的风险。临床医生常使用肌内效贴布或运动贴布进行踝关节贴扎。由于肌内效贴布具有弹性,而运动贴布无法拉伸,因此两者技术应用和生理机制存在差异,进... 详细信息

背景:慢性踝关节不稳患者行走时倾向于过度足内翻,这将增加步行周期支撑相踝关节扭伤的风险。临床医生常使用肌内效贴布或运动贴布进行踝关节贴扎。由于肌内效贴布具有弹性,而运动贴布无法拉伸,因此两者技术应用和生理机制存在差异,进而可能产生不同的康复疗效。目的:对比肌内效贴布和运动贴布干预对慢性踝关节不稳患者步行支撑相足额状面和胫骨水平面运动的影响。方法:40名慢性踝关节不稳患者随机分为肌内效贴布组和运动贴布组,肌内效贴布组从后足内侧向外侧粘贴2条贴布,以产生外翻拉力;运动贴布组采用踝关节闭锁式编篮贴扎。分别于贴扎前后在电动跑台上进行行走测试,利用三维运动分析系统获取受试者足部和胫骨运动学参数。结果与结论:肌内效贴布组贴扎后于支撑相早期足外翻角度增加(P0.05);运动贴布组贴扎后于支撑相晚期胫骨内旋增加(P0.05)。结果表明:与运动贴布相比,肌内效贴布能够提供灵活的拉力,有利于步态周期中支撑相早期足外翻,同时不限制支撑相晚期的正常足内翻。因此,肌内效贴布可能是慢性踝关节不稳患者的实用康复疗法,在纠正踝关节异常运动的同时不限制其自然运动。

关键词：肌内效贴布运动贴布慢性踝关节不稳踝关节运动学步态周期

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