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thermal behavior of an isolator with mode transition inducing back-pressure of a dual-mode scramjet

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Chinese Journal of Aeronautics 2017年第2期30卷 595-601页

作者： Yang Qingchun Bao Wen Chetehouna Khaled Zhang Silong Gascoin Nicolas School of Astronautics Beihang University 100083 China School of Energy Science and Engineering Harbin Institute of Technology 150001 Harbin China INSA Centre Val de Loir 88 Boulevard Lahitolle 18000 Bourges France

Combustion mode transition is a valuable and challenging research area in dual-mode scramjet engines.The thermal behavior of an isolator with mode transition inducing backpressure is investigated by direct-connect dual-mode scramjet experiments and theoretical analysis.Combustion experiments are conducted under the incoming airflow conditions of total temperature1270 K and Mach 2.A small increment of the fuel equivalence ratio is scheduled to trigger mode transition.Correspondingly,the variation of the coolant flow rate is very small.Based on the measured wall pressures,the heat-transfer model can quantify the thermal state variation of the engine with active cooling.Compared with the combustor,mode transition has a greater effect on the isolator thermal behavior,and it significantly changes the isolator heat-flux and wall temperature.To further study the isolator thermal behavior from flight Mach 4 to Mach 7,a theoretical analysis is carried out.Around the critical point of combustion mode transition,sudden changes of the isolator flowfield and thermal state are discussed.

关键词： Combustion mode Dual-mode scramjet Isolator Mode transition thermal behavior

thermal behavior analysis of a pouch type Li[Ni0.7Co0.15Mn0.15]O2-based lithium-ion battery

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Rare Metals 2016年第4期35卷 309-319页

作者： Feng-Ling Yun Ling Tang Wen-Cheng Li Wei-Ren Jin Jing Pang Shi-Gang Lu General Research Institute for Nonferrous Metalsl R&D Center for Vehicle Battery and Energy StorageBeijing 100088China

Since lithium-ion battery with high energy density is the key component for next-generation electrical vehicles, a full understanding of its thermal behaviors at different discharge rates is quite important for the design and thermal management of lithium-ion batteries （LIBs） pack/module. In this work, a 25 Ah pouch type Li[Ni0.7 Co0.15Mn0.15]O2/graphite LIBs with specific energy of 200 Wh.kg-1 were designed to investigate their thermal behaviors, including temperature distribution, heat generation rate, heat capacity and heat transfer coefficient with environment. Results show that the temperature increment of the charged pouch batteries strongly depends on the discharge rate and depth of discharge. The heat generation rate is mainly influenced by the irreversible heat effect, while the reversible heat is important at all discharge rates and contributes much to the middle evolution of the tem- perature during discharge, especially at low rate. Subse- quently, a prediction model with lumped parameters was used to estimate the temperature evolution at different discharge rates of LIBs. The predicted results match well with the experimental results at all discharge rates. Therefore, the thermal model is suitable to predict the average temperature for the large-scale batteries under normal operating conditions.

关键词： Lithium-ionLi[Ni0.7Co0.15Mn0.15]O2 battery thermal behavior High specific energy

thermal behavior of Sr（ll） and Ba（ll）-Diclofenac Complexes in Solid State： Study of the Dehydration and thermal Decomposition

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Chinese Journal of Chemistry 2011年第11期29卷 2271-2277页

作者： Kobelnik, Marcelo Cassimiro, Douglas Lopes Santos, Diogenesdos Dos Ribeiro, Clovis Augusto Crespi, Marisa Spirandelic Centro Universitdrio do Norte Paulista-UNORP Rua Ipiranga 3460 Sao Jose do Rio Preto SP Brazil Instituto de Quimica Sao Paulo State University C.P. 355 14800-900 Araraquara SP Brazil

Solid state compounds of general formula Sr（Diclof）2 ·5.7H2O and Ba（Diclof）2·4.8H2O were obtained. Thermo- gravimetry （TG）, differential scanning calorimetry （DSC）, X-ray diffraction powder patterns and microscopy analysis were used to characterize these compounds. Details concerning the dehydration and thermal decomposition as well as data of kinetic parameters have been described here. The kinetic behaviors of these stages were evaluated from several heating rates with samples masses of 2 and 5 mg in open crucibles under a nitrogen atmosphere. The results of the present study improve the knowledge on these compounds including their dehydration and thermal stability. The obtained data depend on the mass of the sample which results in two kinetic behavior patterns.

关键词： diclofenac divalent metal ions thermal behavior kinetic parameters

thermal behavior, Specific Heat Capacity and Adiabatic Time-to-explosion of GDN

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Chemical Research in Chinese Universities 2009年第1期25卷 76-80页

作者： YANG Xing-kun XU Kang-zhen ZHAO Feng-qi YANG Xin WANG Han SONG Ji-rong WANG Yao-yu College of Chemistry and Chemical Engineering Xinyang Normal University Xinyang 464000 P. R. China Xi＇an Modern Chemistry Research Institute Xi＇an 710065 P. R. China Shaanxi Key Laboratory of Physico-inorganie Chemistry Northwest University Xi＇an 710069 P. R. China

A new compound, [（NH2）2C=NH2]＋N（NO2）2-（GDN）, was prepared by mixing ammonium dinitramide （ADN） and guanidine hydrochloride in water. The thermal behavior of GDN was studied under the non-isothermal conditions with DSC and TG/DTG methods. The apparent activation energy（E） and pre-exponential constant（A） of the exothermic decomposition stage of GDN were 118.75 kJ/mol and 10^10.86 s^-1, respectively. The critical temperature of the thermal explosion（Tb） of GDN was 164.09 ℃. The specific heat capacity of GDN was determined with the Micro-DSC method and the theoretical calculation method, and the standard molar specific heat capacity was 234.76 J·mol^-1·K^-1 at 298.15 K. The adiabatic time-to-explosion of GDN was also calculated to be a certain value between 404.80 and 454.95 s.

关键词： Guanidine dinitramide Ammonium dinitramide thermal behavior Specific heat capacity Adiabatic time-to-explosion

Effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope

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Research in Astronomy and Astrophysics 2021年第6期21卷 253-262页

作者： Shan-Xiang Wei De-Qing Kong Qi-Ming Wang Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The alidade’s non-uniform temperature field of a large radio telescope is very obvious under solar radiation.Estimating a radio telescope’s pointing errors,caused by the alidade deformation under solar radiation,is significant to improve the telescope’s pointing accuracy.To study the effect of the alidade thermal behavior on the pointing accuracy of a large radio telescope,a temperature experiment is first carried out in a 70-m radio telescope on a sunny day.According to the measured results,the temperature distribution rule of the alidade is summarized initially.In addition,the alidade’s temperature field is calculated by finite element thermal analysis.The simulated results are proved to be in good agreement with the experimental results.Finally,the alidade deformation under solar radiation is computed by finite element thermalstructure coupling analysis.The telescope’s pointing errors caused by alidade deformation are estimated via the alidade’s node displacements.The final results show that the effect of alidade thermal behavior on the telescope’s elevation pointing errorsΔε2+Δεr is much more than the effect on the telescope’s crosselevation pointing errorsΔε1.The maximum ofΔε2+Δεr is more than 45″,while the maximum ofΔε1 is less than 6″.This study can provide valuable references for improving the pointing accuracy of large radio telescopes.

关键词： telescopes finite element analysis thermal behavior pointing accuracy

thermal behavior and Crystal Transition of Biodegradable Poly(butylenes adipate)Revealed by Two-Dimensional Correlation Spectroscopy

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光谱学与光谱分析 2016年第S1期36卷 139-140页

作者： CHEN Yu-jing Isao Noda Young Mee Jung Department of Chemistry Kangwon National University Department of Materials Science and Engineering University of Delaware

In the present study,thermal behavior and crystal transition of pure poly(butylene adipate)(PBA)upon heating process were investigated by FTIR spectroscopy.To gain further insight into the thermal behavior alteration and the phase transition of PBA,we performed two-dimensional(2D)correlation analysis.We found thatβ-form PBA crystal undergoes not only the melting process but also crystal transition upon the heating process.

关键词： Poly(butylene adipate) thermal behavior Crystal transition Two-dimensional correlation spec-troscopy

thermal behavior of zirconia-doped mullite gel fibers

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Progress in Natural Science:Materials International 2012年第3期22卷 213-218页

作者： Wei Wang a,b, Duan Weng a, Xiaodong Wu a a State Key Laboratory of New Ceramics and Fine Process, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China b The Second Artillery NCO Academy of PLA, Qingzhou, Shandong 262500, China State Key Laboratory of New Ceramics and Fine Process Department of Materials Science and Engineering Tsinghua University Beijing 100084 China The Second Artillery NCO Academy of PLA Qingzhou Shandong 262500 China

The zirconia-doped mullite gel fibers were prepared via a sol-gel method. The thermal behaviors of the gel fibers during pyrolysis were investigated by means of thermal gravity-differential scanning calorimetry (TG-DSC), in-situ fourier transform infrared spectroscopy (in-situ FTIR), X-ray diffraction (XRD) and transmission electron microscope (TEM). It was found that the mass loss during calcination can be divided into two stages, i.e. 50% below 400 ℃ and 3% during 550-700 ℃. The three exothermic peaks in DSC curves were attributed to the burning of organics, decomposition of nitrates and mullite transformation, respectively. H2O, CO2 and NO2 were generated during the pyrolysis of mullite gel fibers, and the concentration of NO2 was higher than CO2. The activation energy (Ea) of mullite transformation was calculated by a non-isothermal method, which was the smallest for the 1% ZrO2-doped gel fiber (1145 kJ/mol).

关键词： Mullite fiber Zirconia doping thermal behavior Activation energy

A New Co(Ⅱ) Coordination Polymer Based on a Flexible 1,4-Cyclohexanedicarboxylic Acid: Synthesis, Structure and thermal behavior

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Chinese Journal of Structural Chemistry 2019年第12期38卷 2155-2160页

作者：王秀艳李聪邹春凯阚若飞张晓旭徐占林 Key Laboratory of Preparation and Applications of Environmental Friendly Materials Jilin Normal UniversitySiping 136000China Department of Chemistry Jilin Normal UniversitySiping 136000China

A new Co(Ⅱ) coordination polymer, [Co(1,4-chdc)(L)(H2O)]n(1), was synthesized under hydrothermal condition(1,4-H2chdc = 1,4-cyclohexanedicarboxylic acid, L = 2-(4-fluoro-phenyl)-1 H-imidazo[4,5-f][1,10]phenanthroline). Its crystal structure was determined by single-crystal X-ray diffraction. 1 crystallizes in triclinic, space group P1 with a = 8.790(5), b = 10.486(5), c = 13.305(5)A, α = 87.391(5), β = 82.925(5), γ = 81.841(5)°, V = 1204.2(10)A^3, Z = 2, C27H23FN4O5Co, Mr = 561.42, Dc = 1.548 g/cm^3, F(000) = 578, μ(Mo Ka) = 0.769 mm^-1, R = 0.0415 and wR = 0.1043. In 1, each 1,4-chdc anion bridges two neighboring Co(Ⅱ) atoms to give a chain structure. The L ligands are attached on one side of the chain through chelating the Co(Ⅱ) atoms, and are stacked with those of an adjacent chain through π-π interactions, yielding a double-chain structure. The double-chain structures are linked into a supramolecular layer structure through N–H…O hydrogen-bonding interactions between the adjacent double-chain structures. Moreover, the thermal behavior of 1 was also studied.

关键词： cobalt coordination polymer 1,4-cyclohexanedicarboxylic acid π-πinteractions hydrogen bond thermal behavior

Crystal Structures, thermal behavior Analysis and thermal Safety of Two Energetic Salts of Hydrazinyl-1,2,4,5-tetrazine with 3,5-Dinitrosalicylic Acid

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Chemical Research in Chinese Universities 2018年第6期34卷 959-964页

作者： CHEN Xiang ZENG Tian GUO Zhaoqi LI Shuailei MAI Tao GAO Rong MA Haixia School of Chemieal Engineering Northwest University Xi 'an 710069 P. R. China College of Chemistry and Materials Science Northwest University Xi 'an 710069 P. R. China

Two energetic salts, DPHT.DNS-H20（1） and DHT.2DNS.2H20（2）[DPHT=3-（3,5-dimethyl-lH-pyrazol- 1-yl）-6-hydrazinyl-1,2,4,5-tetrazine; DHT=3,6-dihydrazinyl-l,2,4,5-tetrazine], were synthesized from S-tetrazine with 3,5-dinitrosalicylic acid（DNS）. Compounds 1 and 2 were structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction. The thermal behavior of the title compounds was studied by differential scanning calorimetry（DSC） and thermogravimetry（TG）. The non-isothermal decomposition kinetics of compound 2 were investigated. The self-accelerating decomposition temperature, thermal ignition temperature, and critical temperatures of thermal explosion were obtained to evaluate the thermal safety of compound 2. The results show compounds 1 and 2 decompose at 150.8 and 179.2℃, respectively. The TSADT and Tb of compound 2 are higher than those of DHT, which indicates compound 2 is a potential candidate for energetic materials that have good thermal stability. Keywords Tetrazine compound; Dinitrosalicylic acid（DNS）; Crystal structure; thermal behavior; thermal safety

关键词： Tetrazine compound Dinitrosalicylic acid（DNS） Crystal structure thermal behavior thermal safety