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THE INFLUENCE OF THERMAL PERFORMANCE OF TWT CATHODE-HEATER ASSEMBLY BY DIFFERENT CONTACT FORM BETWEEN INNER HEAT SHIELD AND SUPPORT CYLINDER 被引量:2
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作者 Zhai Liang Yu Shiji 《Journal of Electronics(China)》 2011年第4期609-614,共6页
In this paper,the influence of thermal performance of cathode-heater assembly of Traveling Wave Tube(TWT),which has different contact form between inner heat shield and supporting cylinder,is analyzed using the simula... In this paper,the influence of thermal performance of cathode-heater assembly of Traveling Wave Tube(TWT),which has different contact form between inner heat shield and supporting cylinder,is analyzed using the simulation software ANSYS.With both thermal radiation and heat conduction are considered,the temperature and heat flux distribution of structures with different contact form are calculated,and also starting time which is needed before temperature come into steady status.The result of analysis suggests that changing the contact form between inner heat shield and support cylinder can influence the thermal performance of cathode-heater assembly and improve assembly's temperature distribution and promote heater's heating efficiency.The result of this paper provides theoretical guidance in the design of cathode-heater assembly. 展开更多
关键词 Cathode-heater Assembly Contact form thermal performance Starting time ANSYS
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Design and Development of a Parabolic Trough Solar Air Heater for a Greenhouse Dryer
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作者 Eric King’ori Isaac N. Simate 《Journal of Power and Energy Engineering》 2024年第9期1-18,共18页
Design and Development of a Parabolic Trough Solar Air Heater (PTSAH) for a Greenhouse Dryer (GD) was done to improve the dryer’s performance. The materials used for the fabrication of the PTSAH included galvanized s... Design and Development of a Parabolic Trough Solar Air Heater (PTSAH) for a Greenhouse Dryer (GD) was done to improve the dryer’s performance. The materials used for the fabrication of the PTSAH included galvanized sheets covered with aluminium foil, an absorber tube made of GI pipe painted matt black to increase heat absorbance at the focal line, mild steel square tubes, shutter plywood, and an axial fan to push air through the absorber tube. Key geometrical parameters used for the design of the PTSAH were a rim angle of 98 degrees, focal length of 0.2608 m, height of 0.3451 m, length of 2 m, and an aperture width of 1.2 m. The PTSAH’s total aperture surface area was 2.4 m2, while its absorber tube surface area was 0.1587 m2. The PTSAH was experimentally tested to establish its thermal performance. It was found that the ambient air recorded an average value of 31.1˚C and that the air heater could increase the air temperature by 45.6˚C above ambient with a thermal efficiency of 5.3%. It can, therefore, be concluded that the PTSAH can significantly improve the performance of a GD by supplying the GD with air at a higher temperature than ambient. 展开更多
关键词 Solar Air heater Greenhouse Dryer Parabolic Trough thermal Performance
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Effect of obstruction on thermal performance of solar water heaters 被引量:3
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作者 LI Da-peng WANG Yu-fan +2 位作者 LIU Gang LIAO Sheng-ming LIU Xian-ping 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第4期1273-1289,共17页
Solar water heaters(SWH) are widely used in urban areas because of their advantages in reducing energy consumption and mitigating greenhouse gas emissions. However, the performance of SWH subjected to obstructions is ... Solar water heaters(SWH) are widely used in urban areas because of their advantages in reducing energy consumption and mitigating greenhouse gas emissions. However, the performance of SWH subjected to obstructions is unclear yet. In this study, we present a numerical evaluation on thermal performance of fa?ade-installed SWH under three typical obstructed scenarios, based on various levels of sunshine duration. This study is carried out for four locations with various latitudes across China. Thermal performance is measured by solar fraction for annual and monthly evaluation. The results show that the obstruction can seriously degrade annual solar fraction of SWH, even in the 4-hour sunshine duration scenario, for all the studied locations. Interestingly, only lengthening sunshine duration in the standard day(e.g., from 2 h to 4 h) may not result in increasing annual solar fraction markedly. In terms of the monthly performance, solar fraction in January and December decreases significantly, while from May to August it just declines slightly, except for Guangzhou having a swift reduction. This study can provide insights into the behavior and promote the appropriate application of SWH in urban areas. 展开更多
关键词 solar water heaters thermal performance OBSTRUCTION SIMULATION
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Thermal Properties of Crosslinking Modified Ultrahigh Molecular Weight Polyethylene Fibers by Ultra-Violet Irradiation 被引量:8
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作者 于俊荣 陈自力 +1 位作者 杨新戈 刘兆峰 《Journal of China Textile University(English Edition)》 EI CAS 2000年第1期74-76,共3页
By means of ultra-violet(UV)irradiation with photoini-tiator and multifunctional crosslinking agent,thecrosslinking modification of ultrahigh molecular weightpolyethylene(UHMWPE)fibers prepared by gel-spin-ning was ca... By means of ultra-violet(UV)irradiation with photoini-tiator and multifunctional crosslinking agent,thecrosslinking modification of ultrahigh molecular weightpolyethylene(UHMWPE)fibers prepared by gel-spin-ning was carried out.Thermal properties of fiber sampleswere examined using differential scanning calorimetry(DSC),thermomechanical analysis(TMA)apparatusand a manual device.The results indicated that the opti-mal irradiation energy is 250-400 mJ/cm^2,heat-andcreep-resistant behaviors of modified fibers have beenimproved. 展开更多
关键词 UHMWPE fibers thermal property ULTRA - vio-let IRRADIATION modification.
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A Numerical Algorithm Based on Quadratic Finite Element for Two-Dimensional Nonlinear Time Fractional Thermal Diffusion Model 被引量:3
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作者 Yanlong Zhang Baoli Yin +2 位作者 Yue Cao Yang Liu Hong Li 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第3期1081-1098,共18页
In this article,a high-order scheme,which is formulated by combining the quadratic finite element method in space with a second-order time discrete scheme,is developed for looking for the numerical solution of a two-d... In this article,a high-order scheme,which is formulated by combining the quadratic finite element method in space with a second-order time discrete scheme,is developed for looking for the numerical solution of a two-dimensional nonlinear time fractional thermal diffusion model.The time Caputo fractional derivative is approximated by using the L2-1formula,the first-order derivative and nonlinear term are discretized by some second-order approximation formulas,and the quadratic finite element is used to approximate the spatial direction.The error accuracy O(h3+t2)is obtained,which is verified by the numerical results. 展开更多
关键词 Quadratic finite element two-dimensional nonlinear time fractional thermal diffusion model L2-1formula.
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A New Nickel(Ⅱ) Coordination Compound Constructed by Pyridyl-triazole and Oxybis(Benzoic Acid): Synthesis,Crystal Structure and the Effect on the Thermal Decomposition of Ammonium Perchlorate 被引量:5
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作者 韩晶 李婷 李冰 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2015年第2期253-259,共7页
A new energetic complex, Ni(3,4'-Hbpt)2(Hoba)2(H20)2 (3,4'-Hbpt = 3-(3-pyridyl)- 5-(4'-pyridyl)-l-H-l,2,4-triazole and H2oba = 4,4'-oxybis(benzoic acid)), has been synthesized by hydrothermal reactio... A new energetic complex, Ni(3,4'-Hbpt)2(Hoba)2(H20)2 (3,4'-Hbpt = 3-(3-pyridyl)- 5-(4'-pyridyl)-l-H-l,2,4-triazole and H2oba = 4,4'-oxybis(benzoic acid)), has been synthesized by hydrothermal reaction and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric analyses and X-ray powder diffraction. Single-crystal X-ray diffraction analysis indicates that the complex belongs to the monoclinic system, space group P2j/c with a = 10.2357(9), b = 24.594(2), c = 10.4225(9)/k, β = 114.0110(10)°, V = 2396.7(4) A3, Dc = 1.460 g/cm3,μ = 0.482 mm-1, Mr = 1053.63, F(000) = 1088, Z = 2, the final R = 0.0358 and wR = 0.0973 with I 〉 2σ(I). Both 3,4'-Hbpt and H2oba ligands adopt monodentate modes linking one Ni(II) ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 3D supramolecular architecture with hydrogen bonds. In addition, the catalytic performance for thermal decomposition of the efficacy of ammonium perchlorate (AP) is explored by differential scanning calorimetry (DSC), which indicates that the complex is a good candidate for a promoter of the thermal decomposition of ammonium perchlorate. 展开更多
关键词 3-(3-pyridyl)-5-(4'-pyridyl)-l-H-l 2 4-triazole 4 4'-oxybis(benzoic acid) crystal structure thermal decomposition ammonium perchlorate
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A New Co(Ⅱ) Coordination Polymer Based on a Flexible 1,4-Cyclohexanedicarboxylic Acid: Synthesis, Structure and Thermal Behavior 被引量:2
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作者 WANG Xiu-Yan LI Cong +3 位作者 ZOU Chun-Kai KAN Ruo-Fei ZHANG Xiao-Xu XU Zhan-Lin 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2019年第12期2155-2160,共6页
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]p... 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) ?, α = 87.391(5), β = 82.925(5), γ = 81.841(5)o, V = 1204.2(10) ?3, Z = 2, C27H23FN4O5Co, Mr = 561.42, Dc = 1.548 g/cm3, 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. 展开更多
关键词 cobalt coordination polymer 1 4-cyclohexanedicarboxylic acid π-πinteractions hydrogen bond thermal behavior
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Effect of Fused MgO-ZrO_2 Clinker Addition on Thermal Shock Resistance of MgO-ZrO_2 Unfired Bricks 被引量:1
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作者 LI Jiwei ZHOU Ningsheng BAI Hongyu 《China's Refractories》 CAS 2008年第4期11-15,共5页
MgO -ZrO2 unfired bricks with ZrO2 content up to 8% at the interval of 2% were prepared, using fused magnesia ( MgO : 97% ) and fused MgO - ZrO2 clinker ( ZrO2 : 14. 33% ) as starting materials and phenolic resi... MgO -ZrO2 unfired bricks with ZrO2 content up to 8% at the interval of 2% were prepared, using fused magnesia ( MgO : 97% ) and fused MgO - ZrO2 clinker ( ZrO2 : 14. 33% ) as starting materials and phenolic resin as binder. The effects of ZrO2 content on thermal shock resistance (TSR) and other properties such as cold and hot modulus of rupture have been investigated. Re- sidual cold modulus of rupture ratio after heating at 1 000 ℃ and quenching by air blowing was adopted to characterize TSR. Addition of the MgO -ZrO2 clinker improves TSR, attributing to the microcrack toughening effect by thermal expansion mismatch between different phases. When ZrO2 content goes above 4%. the impro- ving effect tends to be moderate. The introduction of MgO- ZrO2 clinker can also improve the HMOR at 1 500 ℃, while the increased ZrO2 content reduces CMOR of the bricks prefired at 1 600 ℃, due to the thermal expansion mismatch effect. Compromising the overall properties, the optimal ZrO2 content for such magnesia based unfired brick is suggested to be 4%. 展开更多
关键词 Magnesia - zirconia system Unfired brick thermal shock resistance Magnesia-zirconia clinker
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Catalytic Kinetic on the Thermal Decomposition of Ammonium Perchlorate with a New Energetic Complex Based on 3,5-Bis(3-pyridyl)-1H-1,2,4-triazole 被引量:2
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作者 高慧 李冰 +3 位作者 靳晓东 毕淑娴 田晓燕 刘万毅 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第12期1902-1911,共10页
A new energetic complex,[Co(3,3?-Hbpt)(Htm)]·H_2O(1,3,3?-Hbpt = 3,5-bis(3-pyridyl)-1H-1,2,4-triazole and H_3tm = trimesic acid),has been synthesized by hydrothermal reactions and characterized by single... A new energetic complex,[Co(3,3?-Hbpt)(Htm)]·H_2O(1,3,3?-Hbpt = 3,5-bis(3-pyridyl)-1H-1,2,4-triazole and H_3tm = trimesic acid),has been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction,elementary analysis,IR spectroscopy,thermogravimetric analysis and X-ray powder diffraction. Single-crystal X-ray diffraction indicates that the complex belongs to triclinic system,space group P 1 with a = 10.0911(1),b = 10.2573(1),c = 10.6393(1) ?,α = 103.793(2),β = 101.041(2),γ = 107.918(3)o,V = 974.9(2) ?~3,Z = 2,D_c = 1.732 g·cm-3,μ = 0.941 mm^(-1),M_r = 508.31,F(000) = 518,the final R = 0.0523 and wR = 0.0935 with I 〉 2σ(I). In the title complex,Co(Ⅱ) ions are connected by Htm2-anions generating 1D ladder-like chains which are linked by 3,3?-Hbpt to form 1D cages. In addition,the thermal decomposition of ammonium perchlorate(AP) with complex 1 was explored by differential scanning calorimetry(DSC). AP is completely decomposed in a shorter time in the presence of complex 1,and the decomposition heat of the mixture is 2.531 kJ·g^(-1),significantly higher than that of pure AP. By Kissinger's method,the ratio of Ea/ln(A) is 11.05 for the mixture,which indicates that complex 1 shows good catalytic activity toward the AP decomposition. 展开更多
关键词 3 5-bis(3-pyridyl)-1H-1 2 4-triazole ammonium perchlorate catalytic thermal decomposition
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Thermal Decomposition Kinetics of Lead 2,4,6-Trinitroresorcinate Monohydrate 被引量:1
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作者 HURong-zu CHENSan-ping +8 位作者 GAOSheng-li ZHAOFeng-qi SONGJi-rong SHIQi-zhen CHENPei LUOYang ZHAOHong-an YAOPu LIJing 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第5期631-636,共6页
The non-isothermal decomposition of lead 2,4,6-trinitroresorcinate monohydrate, Pb(TNR)·H\-2O, was investigated by means of TG-DTA, DSC and IR. The thermal decomposition mechanism and the dissociated kinetics wer... The non-isothermal decomposition of lead 2,4,6-trinitroresorcinate monohydrate, Pb(TNR)·H\-2O, was investigated by means of TG-DTA, DSC and IR. The thermal decomposition mechanism and the dissociated kinetics were also investigated. The kinetic parameters were obtained from the analysis of the DSC curves by integral and differential methods. The most probable kinetic model function of the dehydration reaction of \{Pb(TNR)·H\-2O\} was suggested by the comparison of the kinetic parameters. 展开更多
关键词 Pb(TNR)·H\-2O DSC Non-isothermal kinetics TG-DTA thermal decomposition
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MWCNTs-水合盐复合相变材料的蓄热性能研究
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作者 程家文 曾丽萍 +3 位作者 生梦瑶 苏欢 李文菁 李小华 《太阳能学报》 EI CAS CSCD 北大核心 2023年第8期10-16,共7页
研究CH_(3)COONa·3H_(2)O(SAT)/Na_(2)HPO_(4)·12H_(2)O(DSP)共晶盐的相变过程,分析亲水碳纳米管(HCNTs)对共晶盐热性能的优化效果。结果表明:SAT/DSP质量比为9∶1时共晶盐循环稳定性最好,且过冷度仅为2.5℃;随着HCNTs掺量提... 研究CH_(3)COONa·3H_(2)O(SAT)/Na_(2)HPO_(4)·12H_(2)O(DSP)共晶盐的相变过程,分析亲水碳纳米管(HCNTs)对共晶盐热性能的优化效果。结果表明:SAT/DSP质量比为9∶1时共晶盐循环稳定性最好,且过冷度仅为2.5℃;随着HCNTs掺量提高,复合材料的热导率呈线性增长趋势,最高达到1.29 W/(m·K),较未加HCNTs时提升了182.89%,蓄热密度呈线性下降趋势,最多降低了5.59%。最后对各组HCNTs/SAT/DSP复合相变材料(CPCM)进行200次固-液循环,结果表明各组材料的循环稳定性良好,具备实际应用价值。 展开更多
关键词 复合材料 相变 蓄热 多壁碳纳米管多壁碳纳米管 太阳能热水器 热性能
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Energetic Analysis of Two Thermal Power Plants with Six and Seven Heaters
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作者 Miguel Toledo Juan Abugaber +3 位作者 Raúl Lugo Martín Salazar Alfredo Rodríguez Aldo Rueda 《Open Journal of Applied Sciences》 2014年第1期6-12,共7页
An energetic analysis of two power plants with six and seven heaters was realized in this work and also a feedwater heater was taking into consideration. This analysis considered the temperature and pressure ranges un... An energetic analysis of two power plants with six and seven heaters was realized in this work and also a feedwater heater was taking into consideration. This analysis considered the temperature and pressure ranges under which power generating plants work. The unit thermal consumption (UTC), the specific fuel consumption (SFC) and the specific steam consumption (SSC) were obtained for power generation. The energetic analysis to the cycles of steam with regeneration with six and seven heaters was realized. There was a difference of 0.5% in the values of UTC, SFC and SSC when the pressures of condensation changed. Also an analysis of the behavior of the thermal efficiency in relation to the rise of numbers of heater from two to seven is presented. 展开更多
关键词 ENERGETIC Analysis Feedwater heater thermal Efficiency Rankine CYCLE
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Influence of Microstructures on Thermal Shock and Sintering Behavior of YSZ-based Thermal Barrier Coatings
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作者 Kirsten Bobzin Lidong Zhao +1 位作者 Mehmet ?te Tim K?nigstein 《表面技术》 EI CAS CSCD 北大核心 2019年第4期28-33,共6页
In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal b... In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal barrier coatings exhibited similar overall porosities, but significantly different microstructures. Application of the special spray powder prepared by high energy ball milling led to a microstructure with numerous inclusions of semi-molten agglomerates, which introduced a plethora of clusters of fine pores into the coating and several more microstructural defects. This microstructure resulted in a significantly better thermal shock behavior compared to the conventional thermal barrier coating. The heat treatment of both thermal barrier coatings atθ=1150℃for t=100 h led to a sintering of both coatings. The results were reduced overall porosity and significantly increased fracture toughness. A correlation between the fracture toughness of both coatings after the heat treatment and the thermal shock life time could not be identified. 展开更多
关键词 thermal barrier coating ZrO2-7%Y2O3 high energy ball MILLING thermal shock
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Abugomry Induction Heater Design to Study the Thermal Properties of Magnetic Nanoparticles
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作者 Eltayeb Ibrahim Ahmed Elbeshir 《Journal of Physical Science and Application》 2016年第4期44-47,共4页
In this project a new simple induction heater design (Abugomry) operated at low power and low frequency 100w/100kHz was made. The thermal properties of three different MNPs (magnetic nano particles) were studied b... In this project a new simple induction heater design (Abugomry) operated at low power and low frequency 100w/100kHz was made. The thermal properties of three different MNPs (magnetic nano particles) were studied by Abugomry induction heater. The high temperatures of MNPs (47, 46 and 50) ℃, the heating rate (0.030, 0.025 and 0.028) ℃/min and the specific absorption rate (126, 115 and 105) W/g for the (α-Fe2O3, Fe3O4 and CoFe2O4) MNPs respectively, these results were suitable to use these MNPs in MHT (magnetic hyperthermia treatment). The results accrue from Abugomry of these MNPs that it's agree with the published results of the same MNPs, which were studied by induction heater operated at high/medium power and frequency. 展开更多
关键词 Induction heater thermal properties magnetic nanoparticles hyperthermia.
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Geometric nonlinear formulation for thermal-rigid-flexible coupling system
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作者 Wei Fan Jin-Yang Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第5期728-737,共10页
This paper develops geometric nonlinear hybrid formulation for flexible multibody system with large deformation considering thermal effect. Different from the conventional formulation, the heat flux is the function of... This paper develops geometric nonlinear hybrid formulation for flexible multibody system with large deformation considering thermal effect. Different from the conventional formulation, the heat flux is the function of the rotational angle and the elastic deformation, therefore, the coupling among the temperature, the large overall motion and the elastic deformation should be taken into account. Firstly, based on nonlinear strain-displacement relationship, varia- tional dynamic equations and heat conduction equations for a flexible beam are derived by using virtual work approach, and then, Lagrange dynamics equations and heat conduction equations of the first kind of the flexible multibody system are obtained by leading into the vectors of Lagrange multiplier associated with kinematic and temperature constraint equations. This formulation is used to simulate the thermal included hub-beam system. Comparison of the response be- tween the coupled system and the uncoupled system has re- vealed the thermal chattering phenomenon. Then, the key parameters for stability, including the moment of inertia of the central body, the incident angle, the damping ratio and the response time ratio, are analyzed. This formulation is also used to simulate a three-link system applied with heat flux. Comparison of the results obtained by the proposed formulation with those obtained by the approximate nonlinear model and the linear model shows the significance of con- sidering all the nonlinear terms in the strain in case of large deformation. At last, applicability of the approximate non- linear model and the linear model are clarified in detail. 展开更多
关键词 thermal-rigid-flexible coupling - thermal chattering Large deformation Stability analysis
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Comparison of Thermo-Structural Responses for Integrated Thermal Protection Panels with Different Corrugated Core Configurations
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作者 Shu-Yuan Zhao Jian-Jun Li Xiao-Dong He 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第6期21-28,共8页
To explore new light-weight integrated thermal protection system panel configuration and gain good insight into the responses mechanism,heat transfer and structural field analysis for one single-layer and four double-... To explore new light-weight integrated thermal protection system panel configuration and gain good insight into the responses mechanism,heat transfer and structural field analysis for one single-layer and four double-layer corrugated core panels were performed. The obtained the temperature,buckling,stress and deflection responses were compared,and the deflection and stress distributions as well as thermal buckling mode at the time were discussed for the considered configurations when the temperature difference between the top and bottom face sheet was maximum. The results demonstrated that the non-orthogonal and hat-stiffened double-layer structures provide superior performance to resist thermal buckling deformation in comparison with other configurations. The useful information is provided for the forthcoming optimization in which thermal buckling is considered as critical design driver. 展开更多
关键词 Integrated thermal Protection System corrugated heat transfer thermal bucklingCLC number:V214.4 Document code:AArticle ID:1005-9113(2013)06-0021-08
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Thermal Expansion Behavior of La1-xSrxMn1-yCoyO3-δ Perovskites
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作者 WenhuiMA GangXIE 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第3期286-287,共2页
The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 ... The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure. 展开更多
关键词 thermal expansion La1-xSrxMn1-yCoyO3-δ Solid reaction synthesis
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Preparation and spectroscopic, and thermal decomposition kinetic studies of europium(Ⅲ) complex [Eu(HNBD)_3] (HNBD: 1-(6-hydroxy-1-naphthyl)-1,3-butanedione)
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作者 WANG Dunjia ZHENG Chunyang SUN Tingquan 《Rare Metals》 SCIE EI CAS CSCD 2007年第4期335-341,共7页
The complex of Eu(IH) with 1-(6-hydroxy- 1-naphthyl)- 1,3-butanedione (HNBD) was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The... The complex of Eu(IH) with 1-(6-hydroxy- 1-naphthyl)- 1,3-butanedione (HNBD) was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu(Ⅲ) ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu^3+ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods (Coat-Redfem equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation). The kinetic parameters of the first stage are E^* = 164.02 kJ.moll, A = 1.31 × 10^15 s^-l, AS^*= 42.27 J·K^-l·mol^-l, △H^* = 159.51 kJ·mol^-l, △G^*= 136.54 kJ·mol^-l, and n = 3.1, those of the second stage are E^*= 128.52 kJ·mol^-l, A = 1.44× 106 s^-1, △S^*= - 136.89 J·K^-l·mol^-l, △H^* = 120.41 kJ·mol^-l, △G^*= 283.85 kJ·mol^-l, and n = 1.1. 展开更多
关键词 physical chemistry thermal decomposition kinetics spectroscopic studies Eu(Ⅲ) complex 1-(6-hydroxy-1-naphthyl)- 1 3-butanedione
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The influence of thermal radiation on MHD station-point flow past a stretching sheet with heat generation
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作者 Jing Zhu.Lian-Cun Zheng.Xin-Xin Zhang Department of Mathematics and Mechanics,University of Science and Technology Beijing,100083 Beijing,China Thermal Engineering Department,University of Science and Technology Beijing,100083 Beijing,China 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第4期502-509,共8页
This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generatio... This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generation or absorption. The analytical solutions for the velocity distribution and dimensionless temperature profiles are obtained for the various values of the ratio of free stream velocity and stretching velocity, heat source parameter, Prandtl number, thermal radiation parameter, the suction and injection velocity parameter and magnetic parameter and dimensionality index in the series form with the help of homotopy analysis method (HAM). Convergence of the series is explicitly dis- cussed. In addition, shear stress and heat flux at the surface are calculated. 展开更多
关键词 thermal radiation MHD Laminar boundarylayers - Homotopy analysis method
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NON-ISOTHERMAL KINETICS OF THERMAL DECOMPOSITION OF A NOVEL ANTITUMOR AGENT 4-{5-[3,4-DIMETHYL-5-(3,4,5-TRIMETHOXYPHENYL) THIOPHEN-2-YL ] -2-METHOXYPHENYL} MORPHOLINE
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作者 雷英杰 石继仙 俞玫 《Transactions of Tianjin University》 EI CAS 2006年第1期46-49,共4页
The thermal decomposition of a new antitumor agent, 4-{5-[ 3,4-dimethyl-5-(3,4,5-trimethoxyphenyl)thiophen-2-yl ]-2-methoxyphenyl} morpholine was studied by Differential Scanning Calorimetry (DSC) and Thermogravim... The thermal decomposition of a new antitumor agent, 4-{5-[ 3,4-dimethyl-5-(3,4,5-trimethoxyphenyl)thiophen-2-yl ]-2-methoxyphenyl} morpholine was studied by Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG) / Derivative Thermogravimetry ( DTG ) methods at a flow rate of nitrogen gas of 120 mL/min, The kinetic parameters were obtained from the analysis of the corresponding curves by Kissinger's method, Ozawa's method and the integral method, The results indicate that the apparent activation energy and pre-exponential constants of the decomposition reaction are 106.67 kJ/mol and 10^6.19s^-1, respectively. 展开更多
关键词 4-{5-[3 4-Dimethyl-5-(3 4 5-Trimethoxyphenyl)Thiophen-2-yl]-2-Methoxyphenyl}morpholine thermal decomposition kinetics
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