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Development of a displacement-reactivity feedback model for dynamic behavior simulation in fast burst reactor

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Nuclear Science and Techniques 2019年第5期30卷 82-91页

作者： Jiang-Meng Wang Hui Gao Qi-Lin Xie xiao-qiang fan Da-Zhi Qian Key Laboratory of Neutron Physics China Academy of Engineering Physics Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics

In this study, a displacement-reactivity feedback model, which can directly represent the inherent ‘‘thermal expansion extinction effect'' of fast burst reactors(FBRs),was developed with the aid of the static neutron transport component of the FBR-MPC code. Dynamic behaviors of bursts in the Godiva I reactor were simulated by coupling the simplified multiphysics models consisting of the point kinetic equations for neutronics, adiabatic equation for temperature, and thermoelastic equations for displacement/stress with the developed model. The results were compared with the corresponding experimental data and those obtained using the traditional fission yield(temperature rise)-reactivity feedback models. It was found that the developed model can provide good results for the bursts with no or a small inertia effect. For the bursts with a prominent inertia effect, the smaller burst width and asymmetric distribution of the fission rate curve, noticed in the experiments but not evident using the traditional models, can be reproduced. In addition, the realistic oscillations in reactivity and fission rate caused by the core vibration, as well as the deeper sub-prompt criticality in the plateau following the burst, can be observed. Therefore, the developed displacement-reactivity feedback model can be expected to be an effective tool for calculating the dynamic behaviors of bursts.

关键词： Displacement-reactivity feedback model Prompt supercritical Coupled calculation Fast burst reactor

Effect of electrochemical etching current on prepared perforated silicon structures for neutron detectors

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Frontiers of Materials Science 2013年第1期7卷 96-101页

作者： xiao-qiang fan Yong JIANG Chang-Yong ZHAN Yu ZOU Jian-Chun WU Ning-Kang HUANG Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China Key Laboratory of Radiation Physics and Technology (Ministry of Education) Institute of Nuclear Science and Technology Sichuan University Chengdu 610064 China

Neutron detector based on perforated silicon structures backfilled with neutron converting materials could be operated at a low voltage and improves the detection efficiency of thermal neutron. It is found that the intrinsic detection efficiency of thermal neutron is affected by a lot of factors such as the geometry, size, and depth of the perforation and so on. In this study, the perforated silicon was prepared by electrochemical etching. Effect of etching current on geometry, size, and depth of the perforated silicon structures for neutron detectors was also reported.

关键词： neutron detector silicon electrochemical etching current

Research on the quasi-isentropic driving model of aluminized explosives in the detonation wave propagation direction

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Defence Technology（防务技术） 2024年第2期32卷 596-618页

作者： Hongfu Wang Yan Liu fan Bai Chao He Yingliang Xu qiang Zhou Chuan xiao Fenglei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China China Research and Development Academy of Machinery Equipment Beijing100089China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120China

Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation *** research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was

关键词： Aluminized explosive Flyer plate experiment Quasi-isentropic theoretical model Al reaction Driving characteristics

Influence of oxygen-rich hot air composite gas medium on sintering performance and function mechanism

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Journal of Iron and Steel Research International 2024年第5期31卷 1071-1081页

作者： Min Gan Hao-xiang Zheng xiao-hui fan Zhi-yun Ji qiang Li Ming Wu Yi-fan Wang xiao-long Wang Yu-feng Wu Xu-ling Chen Zeng-qing Sun xiao-xian Huang School of Minerals Processing and Bioengineering Central South UniversityChangsha410083HunanChina Shanxi Taigang Stainless Steel Co. Ltd.Taiyuan030003ShanxiChina

Hot air sintering technology is used to improve the quality and production efficiency of sintered ***,the current thick layer condition highlights the disadvantage of the low oxygen potential of the hot air sintering ***,it is considered to use oxygen enrichment sintering to improve the environment of hot air *** sintering,hot air sintering,and oxygen-rich hot air sintering were compared through sintering cup experiments,and the influence of hot air and oxygen-rich hot air on sintering indexes was *** air reduced the vertical sintering velocity,while improved the yield and tumbler ***-rich hot air sintering contributed to improving the vertical sintering velocity while ensuring the quality of sintered ore,thus comprehensively improving production *** the action of hot air,the highest temperature of the sintering layer increased and the high-temperature holding time was *** oxygen enrichment,the combustion efficiency of fuels in the upper layer of materials was promoted,which optimized heat distribution in the middle and lower layers of materials and increased the content of calcium ferrite in the sintered ore,thus strengthening the sintering process.

关键词： Iron ore sintering Hot air sintering Oxygen enrichment Function mechanism

Effects of bump parameters on hypersonic inlet starting performance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第10期23卷 807-819页

作者： Shang-cheng XU Yi WANG Zhen-guo WANG xiao-qiang fan Bing XIONG College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Unstart is an unwanted flow phenomenon in a hypersonic inlet. When an unstart occurs, the captured airflow flowing through the engine significantly decreases with strong unsteady characteristics, which may lead to thrust loss or even combustor flameout. In this study, various bump configurations were designed to be integrated with a hypersonic inlet to improve its starting ability. A bump was defined as an integrated 3D compression surface installed upstream of the inlet entrance. The starting processes of these bump inlets were numerically simulated to investigate the effect laws and flow mechanisms of the bump parameters. Tests on bump height revealed that the starting performance could be significantly improved by increasing bump height, with the starting Mach number decreasing by 0.55 for the inlet with the highest bump. The high bump facilitates the side movement of the subsonic flow in the separation zone, which leads to a small separation bubble, thus accelerating the starting process. Further, the starting ability can be improved by designing a relatively wide bump, which results in a decline in the starting Mach number by 0.44. When the bump has the same or greater width compared with the airflow capture range, a growing spillage along the transverse direction can be formed so that the airflow in the separation bubble can be easily excluded, improving the starting ability.

关键词： Hypersonic inlet Bump Boundary layer flow Starting performance Large-scale separation bubble

Design method for hypersonic bump inlet based on transverse pressure gradient

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第6期23卷 479-494页

作者： Shang-cheng XU Yi WANG Zhen-guo WANG xiao-qiang fan Bing XIONG College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Transverse pressure gradient(TPG)is one of the key factors influencing the boundary layer airflow diversion in a bump *** paper proposes a novel TPG-based hypersonic bump inlet design *** method consists of two ***,a parametric optimization approach is employed to design a series of 2D inlets with various compression ***,according to the prescribed TPG,the optimized inlets are placed in different osculating planes to generate a 3D bump *** method provides a means to directly control the aerodynamic parameters of the bump rather than the geometric *** performing this method to a hypersonic chin inlet,a long and wide bump surface is formed in the compression wall,which leads to good integration of the bump/*** show that a part of the near-wall boundary layer flow is diverted by the bump,resulting in a slight decrease in the mass flow but a significant improvement in the total pressure *** addition,the starting ability is significantly improved by adding the bump *** reveals that the bump has a 3D rebuilding effect on the large-scale separation bubble of the unstarted ***,a mass flow correction is performed on the designed bump inlet to increase the mass flow to full airflow *** results show that the mass flow rate of the corrected bump inlet reaches up to 0.9993,demonstrating that the correction method is effective.

关键词： Hypersonic bump inlet Transverse pressure gradient(TPG) Boundary layer flow Total pressure recovery Starting ability Mass flow correction

A brand new green coating technology for realizing the regulation of spherical propellant energy release process

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Defence Technology（防务技术） 2024年第6期36卷 78-94页

作者： Wenhao fan Yajun Ding Zhongliang xiao School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China Key Laboratory of Special Energy Materials Nanjing University of Science and TechnologyMinistry of EducationNanjing 210094China

To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to successfully prepare the coated spherical propellant for the first *** effects of fluidized bed coating temperature,air velocity,flow speed and atomization pressure on the adhesion rate,coating integrity and coating uniformity of the coated spherical propellant were investigated,and the preparation of coated spherical propellant with homogeneous size and structural integrity was achieved for the first *** microscopic morphology,chemical structure,water vapor adsorption behavior,combustion performance,and ageing resistance property of the coated spherical propellant were systematically investigated by,Fourier transforms infrared spectroscopy(FTIR),Micro confocal raman spectrometer,field scanning electron microscopy(SEM),dynamic vapor adsorption techniques,and closed bomb test,confirming the surface core-shell structure and the tightly bonded interfacial structure of coated spherical ***,the coated spherical propellant has good hygroscopic,excellent progressive burning and long storage stability.

关键词： Nanocomposites aqueous coating Fluidized bed coating equipment Coated spherical propellant Controllable release of energy Long storage stability

Current understanding of ELF4 deficiency:a novel inborn error of immunity

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World Journal of Pediatrics 2024年第5期20卷 444-450页

作者： Hong-qiang Du xiao-Dong Zhao Department of Rheumatology&Immunology National Clinical Research Center for Child Health and DisordersMinistry of Education Key Laboratory of Child Development and DisordersChongqing Key Laboratory of Child Rare Diseases in Infection and ImmunityChildren’s Hospital of Chongqing Medical UniversityZhongshan Er Road 136Yuzhong DistrictChongqingChina

Background ELF4 deficiency has been recently recognized as a novel disorder within the spectrum of inborn errors of immunity(IEIs),specifically categorized as a“disease of immune dysregulation.”Cases of this condition,reported by our team and others,are very limited *** such,our current knowledge of this new disease remains *** review aims to provide a brief overview of the clinical manifestations,pathogenesis,and treatment strategies for this novel *** sources A comprehensive review was conducted after an extensive literature search in the PubMed/Medline database and websites concerning transcriptional factor ELF4 and reports concerning patients with ELF4 *** search strategy was“ELF4 OR ETS-related transcription factor Elf-4 OR EL4-like factor 4 OR myeloid Elf-1-like factor”as of the time of manuscript *** The current signature manifestations of ELF4 deficiency disorder are recurrent and prolonged oral ulcer,abdominal pain,and diarrhea in pediatric *** some cases,immunodeficiency and autoimmunity can also be *** Sanger sequencing or whole exome sequencing can be used to detect variation in ELF4 *** blotting for ELF4 expression of the patient’s cells can confirm the pathogenic effect of the *** fully confirm the pathogenicity of the variant,further functional test is strongly *** and biologics are the mainstream management of ELF4 deficiency *** Pediatric males presenting with recurring ulcerations in digestive tract epithelium with or without recurrent fever should be suspected of *** atypical presentations are prominent,variations in ELF4 gene should be carefully evaluated functionally due to the complex nature of ELF4 *** of treating DEX includes use of glucocorticoid and biologics and more precise treatment needs more patients to identify and further mechanistic study.

关键词： ELF4 transcription factor Immune dysregulation Inborn errors of immunity Mechanism Recurrent infections

Non-contact and full-field online monitoring of curing temperature during the in-situ heating process based on deep learning

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Advances in Manufacturing 2024年第1期12卷 167-176页

作者： qiang-qiang Liu Shu-Ting Liu Ying-Guang Li Xu Liu xiao-Zhong Hao College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016People’s Republic of China School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing211816People’s Republic of China

Online monitoring of the curing temperature field is essential to improving the quality and efficiency of the manufacturing process of composite *** embedded sensor-based technologies have difficulty monitoring the full temperature field or have to introduce heterogeneous items that could have an undesired impact on the *** this paper,a non-contact,full-field monitoring method based on deep learning that predicts the internal temperature field of composite parts in real time using surface temperature measurements of auxiliary materials is *** the proposed method,an average temperature monitoring accuracy of 97%is achieved in various heating *** addition,this method also demonstrates satisfying feasibility when a stronger thermal barrier covers the *** method was experimentally validated during the self-resistance electric heating process,in which the monitoring accuracy reached 93.1%.This method can potentially be applied to automated manufacturing and process control in the composites industry.

关键词： Online monitoring Curing temperature field Deep learning(DL) In-situ heating