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Effects of ignition voltage and electrode structure on electric ignition and combustion characteristics of Ammonium Dinitramide(ADN)-based liquid propellants in electric ignition mode in inert gas environment

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Chinese Journal of Aeronautics 2024年第4期37卷 229-242页

作者： Lei li guoxiu li Hongmeng li Zhaopu YAO Tao ZHANG Jinze WU Shuo ZHANG School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Control Engineering Beijing 100190China

Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant has the advantages of higher specific impulse, being non-toxic,pollution-free, and easy storage. However, an ADN-based space engine in orbit has exposed the problems of high-temperature deactivation of catalysts and cold-start failure. An active ignition technology—electric ignition technology was explored in this paper to break through the technical bottleneck of catalyst deactivation and the inability to a cold start. An experimental system of a constant-volume combustor for the ADN-based liquid propellant based on the electric ignition method was established. The electric ignition and combustion characteristics of the ADN-based liquid propellant in a volume combustor with an electric ignition method were studied. The influencing mechanisms of the ignition voltage and the electrode structure on the electric ignition characteristics of the ADN-based liquid propellant were investigated. An elevation of the ignition voltage could facilitate the ignition process of the ADN-based liquid propellant, curtail electric energy input and heating effect, while exerting an adverse impact on the combustion process of the propellant.An increase in the ignition voltage enhanced the ignition process of the propellant while simultaneously suppressing its combustion process when utilizing mesh electrodes. Compared to the strip electrodes, the mesh electrodes increased the contact area between the electrodes and the propellant,increased the electric energy input power in the electric ignition process, and reduced the ignition delay time. The mesh electrodes could promote the combustion process of the propellant to a certain extent.

关键词： ADN-based liquid propellant Resistive ignition Electrical ignition characteristic Combustion Inert gas

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Engineering Strategies for Suppressing the Shuttle Effect in lithium–Sulfur Batteries

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Nano-Micro Letters 2024年第1期16卷 187-221页

作者： Jiayi li li Gao Fengying Pan Cheng Gong limeng Sun Hong Gao Jinqiang Zhang Yufei Zhao guoxiu Wang Hao liu Joint International Laboratory On Environmental and Energy Frontier Materials School of Environmental and Chemical EngineeringShanghai UniversityShanghaiPeople’s Republic of China Centre for Clean Energy Technology University of Technology SydneyBroadwaySydneyNSW 2007Australia

lithium–sulfur(li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value.Many methods were proposed for inhibiting the shuttle effect of polysulfide,improving corresponding redox kinetics and enhancing the integral performance of li–S batteries.Here,we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of li–S batteries.First,the electrochemical principles/mechanism and origin of the shuttle effect are described in detail.Moreover,the efficient strategies,including boosting the sulfur conversion rate of sulfur,confining sulfur or lithium polysulfides(LPS)within cathode host,confining LPS in the shield layer,and preventing LPS from contacting the anode,will be discussed to suppress the shuttle effect.Then,recent advances in inhibition of shuttle effect in cathode,electrolyte,separator,and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for li–S batteries.Finally,we present prospects for inhibition of the LPS shuttle and potential development directions in li–S batteries.

关键词： Shuttle effect Designed strategies li-S battery lithium polysulfides

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Kinetic effects of nanosecond discharge on ignition delay time

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Chinese Journal of Chemical Engineering 2016年第12期24卷 1719-1727页

作者： Xingqian Mao guoxiu li Qi Chen Yujun Zhao School of Mechanical Electronic and Control Engineering Beijing Jiaotong University

The effects of nanosecond discharge on ignition characteristics of a stoichiometric methane–air mixture without inert diluent gas were studied by numerical simulation at 0.1 MPa and an initial temperature of 1300 K. A modified non-equilibrium plasma kinetic model was developed to simulate the temporal evolution of particles produced during nanosecond discharge and its afterglow. As important roles in ignition, path fluxes of O and H radicals were analyzed in detail. Different strength of E/N and different discharge duration were applied to the discharge process in this study. And the results presented that a deposited energy of 1–30 m J·cm^(-3) could dramatically reduce the ignition delay time. Furthermore, temperature and radicals analysis was conducted to investigate the effect of non-equilibrium plasma on production of intermediate radicals. Finally, sensitivity analysis was employed to have further understanding on ignition chemistries of the mixture under nanosecond discharge.

关键词：毫微秒分泌物点火延期时间甲烷运动建模数字模拟

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Catalytic bed slenderness ratio and ADN/methanol ratio for decomposition and combustion characteristics within ammonium dinitramide(ADN)-based green aerospace thruster

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Chinese Journal of Chemical Engineering 2019年第5期27卷 1159-1165页

作者： Jun Chen guoxiu li Tao Zhang Yinglong liu Rui Yang Yang Chen School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Control Engineering Beijing 100190China Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology Beijing 100190China

The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and operation parameters (mass fraction ratio of ADN/CH3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure-mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed w让h a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance. These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.

关键词： ADN-based thruster Catalytic bed structure Operation parameters Decomposition and combustion Thruster

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以可解释工具重探基于深度学习的谣言检测

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数据分析与知识发现 2024年第4期8卷 1-13页

作者：贺国秀任佳渝李宗耀林晨曦蔚海燕华东师范大学经济与管理学院上海200062

【目的】探究基于内容的深度谣言检测模型能否真正识别谣言的关键语义。【方法】基于谣言检测任务的中英文基准数据集,本文分别利用基于局部代理模型的可解释工具liME和基于合作博弈论的可解释工具SHAP,分析BERT模型所识别出的关键特征... 详细信息

【目的】探究基于内容的深度谣言检测模型能否真正识别谣言的关键语义。【方法】基于谣言检测任务的中英文基准数据集,本文分别利用基于局部代理模型的可解释工具liME和基于合作博弈论的可解释工具SHAP,分析BERT模型所识别出的关键特征,并判断其是否能反映谣言特性。【结果】可解释工具在不同模型与数据集上计算得出的关键特征差异性较大,无法辨别模型识别的重要特征和谣言之间的语义关系。【局限】本文验证的数据集和模型数量都十分有限。【结论】基于深度学习的谣言检测模型仅拟合了训练集的特征,面向多样的真实场景缺少足够的泛化性和可解释性。

关键词：谣言检测可解释机器学习深度学习 liME SHAP

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基于冷暖季放牧区划分的玉树州草畜平衡估算及变化分析

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草业科学 2024年第4期41卷 1007-1019页

作者：夏兴生马国秀车红岩潘耀忠黄永生李宏达青海师范大学高原科学与可持续发展研究院青海西宁810016 青海师范大学地理科学学院青海西宁810016 北京师范大学地理科学学部遥感科学国家重点实验室北京100875 青海省草原总站青海西宁810008

玉树州作为三江源高寒生态屏障区以牧为主农牧业结合发展的核心地区,草畜平衡不仅关系生态屏障安全,也对实现科学的畜牧业经济管理具有重要的指导意义。因此,本研究以探究高寒生态屏障区天然草地的草畜平衡变化为目的,选择玉树州为研究... 详细信息

玉树州作为三江源高寒生态屏障区以牧为主农牧业结合发展的核心地区,草畜平衡不仅关系生态屏障安全,也对实现科学的畜牧业经济管理具有重要的指导意义。因此,本研究以探究高寒生态屏障区天然草地的草畜平衡变化为目的,选择玉树州为研究区,利用2014-2019年MOD13A1 NDVI产品数据和MOD17A3H NPP产品数据、统计数据、植被类型数据,在划分县域冷暖两季放牧区的基础上,以“木桶效应”确定了各县(市)天然草地的合理载畜量并对其草畜平衡进行了评估。结果表明:1)按照理论上的自然轮牧规律,参考固定面积比例和年内NDVI的时空分布规律划分的玉树州各县(市)冷季放牧区分布于较温暖的沟谷地区,暖季放牧区处于高寒区域,且冷季放牧区产草量大于暖季放牧区。2)年际间冷暖季放牧区干草产量均呈波动增长趋势,年均增长率均在3.00%以上且暖季放牧区年产草量增长率大于冷季放牧区。3)2014-2019年玉树州整体的草畜平衡状态由临界超载和超载波动转为平衡,但各县(市)草畜平衡状态存在差异,推测可能是因为自然保护区和国家公园生态工程支持的空间范围差异引起的。本研究对进一步修订三江源自然保护区和国家公园建设方案,实施高寒生态屏障区生态和畜牧业经济的良性发展策略具有一定的参考价值。

关键词：遥感轮牧木桶效应高寒草地载畜量生态屏障区青藏高原

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Evaluation of Antibiotic Pollution in Soil of Vegetable Base in Yangling District,Shaanxi Province

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Asian Agricultural Research 2021年第11期13卷 47-51页

作者： guoxiu li lihui CUI Yingsha liU Department of Biological Engineering Yangling Vocational and Technical CollegeYangling 712100China

[Objectives]To evaluate the pollution status of antibiotics in the soil of vegetable bases in Yangling District.[Methods]The contents of 19 antibiotics in 4 categories of quinolones,tetracyclines,sulfonamides and macrolides in soil samples from 20 bases were detected and analyzed using HPLC-MS/MS.[Results]The quinolones,sulfonamides and tetracyclines were all detected in 100%of soil samples,and the detection rate of macrolides was 62%.The average contents of the four antibiotics from high to low were quinolones(51.76μg/kg)>tetracyclines(12.77μg/kg)>sulfonamides(1.14μg/kg)>macrolides(0.28μg/kg),and norfloxacin,oxytetracycline,sulfamethazine and erythromycin were the main contents,respectively.According to the trigger value of ecological toxic effect of antibiotics in soil(100μg/kg)proposed by the Steering Committee of the International Coordinating Committee for Veterinary Medicine(VICH),the contents of the four classes of antibiotics in the soil of the study area were all lower than the trigger value,indicating a small ecological risk.[Conclusions]Compared with other domestic research reports,the vegetable bases in this study area are also at a relatively low level of antibiotic pollution.

关键词： Vegetables Soil Antibiotics Pollution evaluation

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Flexible sodium-ion capacitors boosted by high electrochemicallyreactive and structurally-stable Sb_(2)S_(3)nanowire/Ti_(3)C_(2)Tx MXene film anodes

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Nano Research 2023年第4期16卷 5592-5600页

作者： Jian Yang Tianyi Wang Xin Guo Xiaoxue Sheng Jiabao li Chengyin Wang guoxiu Wang Institute for Innovative Materials and Energy Faculty of Chemistry and Chemical EngineeringYangzhou UniversityYangzhou 225002China Centre for Clean Energy Technology School of Mathematics and PhysicsFaculty of ScienceUniversity of Technology SydneySydneyNSW 2007Australia

The rapid development of portable,foldable,and wearable electronic devices requires flexible energy storage systems.Sodiumion capacitors(SICs)combining the high energy of batteries and the high power of supercapacitors are promising solutions.However,the lack of flexible and durable electrode materials that allow fast and reversible Na+storage hinders the development of flexible SICs.Herein,we report a high-capacity,free-standing and flexible Sb2S3/Ti_(3)C_(2)Tx composite film for fast and stable sodium storage.In this hybrid nano-architecture,the Sb_(2)S_(3)nanowires uniformly anchored between Ti_(3)C_(2)Tx nanosheets not only act as sodium storage reservoirs but also pillar the two-dimensional(2D)Ti_(3)C_(2)Tx to form three-dimensional(3D)channels benefiting for electrolyte penetration.Meanwhile,the highly conductive Ti_(3)C_(2)Tx nanosheets provide rapid electron transport pathways,confine the volume expansion of Sb_(2)S_(3)during sodiation,and restrain the dissolution of discharged sodium polysulfides through physical constraint and chemical absorption.Owing to the synergistic effects of the one-dimensional(1D)Sb_(2)S_(3)nanowires and 2D MXenes,the resultant composite anodes exhibit outstanding rate performance(553 mAh·g−1 at 2 A·g−1)and cycle stability in sodium-ion batteries.Moreover,the flexible SICs using Sb2S3/Ti_(3)C_(2)Tx anodes and active carbon/reduced graphene oxide(AC/rGO)paper cathodes deliver a superior energy and power density in comparison with previously reported devices,as well as an excellent cycling performance with a high capacity retention of 82.78%after 5,000 cycles.This work sheds light on the design of next-generation low-cost,flexible and fast-charging energy storage devices.

关键词： MXene Sb_(2)S_(3)nanowires flexible energy storage devices sodium-ion batteries sodium-ion capacitors

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Study on Phthalate Esters Pollution in the Soil of Facility Vegetable Base in Yangling District of Xianyang City

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Asian Agricultural Research 2021年第10期13卷 37-40页

作者： guoxiu li lihui CUI Wei liU Xiaoning liU Department of Biological Engineering Yangling Vocational&Technical CollegeYangling 712100China

[Objectives]To evaluate the pollution status of phthalate esters(PAEs)in the soil of facility vegetable base in Yangling District of Xianyang City.[Methods]A total of 15 kinds of PAEs in soil samples were detected and analyzed by gas chromatography-mass spectrometry.[Results]A total of 12 kinds of PAEs were detected in analyzed soil samples,with a total content of 53.4-3524.1μg/kg and an average of 602.7μg/kg.Specifically,DEHP,DBP,DIBP,DMEP,BBP and DNOP were the main PAEs pollutants in the soil,with the detection rates of 100%,100%,100%,73.3%,63.3%and 53.3%,and the average content were 286.3,167.3,123.1,157.6,121.3,and 130.5μg/kg,respectively.[Conclusions]Compared with the soil in other regions,the pollution level of PAEs in the soil of facility vegetable base in Yangling District is lower,but such compounds are widespread in the facility vegetable base,and their potential environmental risks should attract close attention.

关键词： Phthalate esters(PAEs) Vegetable base Soil Pollution status

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Interface Engineering of Fe_(7)S_(8)/FeS_(2) Heterostructure in situ Encapsulated into Nitrogen‑Doped Carbon Nanotubes for High Power Sodium‑Ion Batteries

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Nano-Micro Letters 2023年第8期15卷 167-180页

作者： Penghao Song Jian Yang Chengyin Wang Tianyi Wang Hong Gao guoxiu Wang Jiabao li College of Chemistry and Chemical Engineering Yangzhou University180 Si‑Wang‑Ting RoadYangzhou 225002JiangsuPeople’s Republic of China Centre for Clean Energy Technology Faculty of ScienceUniversity of Technology SydneyPO Box 123BroadwayNSW 2007Australia Key Lab of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education College of Chemistry and Chemical EngineeringJiangxi Normal UniversityNanchang 330022People’s Republic of China

Heterostructure engineering combined with carbonaceous materials shows great promise toward promoting sluggish kinetics,improving electronic conductivity,and mitigating the huge expansion of transition metal sulfide electrodes for high-performance sodium storage.Herein,the iron sulfide-based heterostructures in situ hybridized with nitrogen-doped carbon nanotubes(Fe_(7)S_(8)/FeS_(2)/NCNT)have been prepared through a successive pyrolysis and sulfidation approach.The Fe_(7)S_(8)/FeS_(2)/NCNT heterostructure delivered a high reversible capacity of 403.2 mAh g^(−1) up to 100 cycles at 1.0 A g^(−1) and superior rate capability(273.4 mAh g^(−1) at 20.0 A g^(−1))in ester-based electrolyte.Meanwhile,the electrodes also demonstrated long-term cycling stability(466.7 mAh g^(−1) after 1,000 cycles at 5.0 A g^(−1))and outstanding rate capability(536.5 mAh g^(−1) at 20.0 A g^(−1))in ether-based electrolyte.This outstanding performance could be mainly attributed to the fast sodium-ion diffusion kinetics,high capacitive contribution,and convenient interfacial dynamics in ether-based electrolyte.

关键词： Iron sulfides Heterostructure Nitrogen-doped carbon nanotubes Ester-based electrolyte Ether-based electrolyte

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