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Nuclear Science and Techniques 2020年第7期31卷 25-33页

作者： Cheng-Long Wang Hao Qin Da-Lin Zhang Wen-Xi Tian Guang-Hui Su sui-zheng qiu Department of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The limited availability of studies on the natural convection heat transfer characteristics of fluoride salt has hindered progress in the design of passive residual heat removal systems(PRHRS)for molten salt *** paper presents results from a numerical investigation of natural convection heat transfer characteristics of fluoride salt and heat pipes in the drain tank of a *** results are compared with experimental data,demonstrating the accuracy of the calculation *** distribution of fluoride salt and heat transfer characteristics are obtained and *** radial temperature of liquid fluoride salt in the drain tank shows a uniform distribution,while temperatures increase with increase in axial height from the bottom to the top of the drain *** addition,natural convection intensity increases with increase in height of the heat pipes in the *** between heat pipes has no obvious effect on the natural convection heat transfer *** study will contribute to the design of passive heat removal systems for advanced nuclear reactors.

关键词： passive characteristics pipes

Thermal–hydraulic analysis of space nuclear reactor TOPAZ-Ⅱ with modified RELAP5

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Nuclear Science and Techniques 2019年第1期30卷 121-131页

作者： Cheng-Long Wang Tian-Cai Liu Si-Miao Tang Wen-Xi Tian sui-zheng qiu Guang-Hui Su Department of Nuclear Science and Technology Xi'an Jiaotong University China Institute of Atomic Energy

With the advantages of high reliability, power density, and long life, nuclear power reactors have become a promising option for space power. In this study, the Reactor Excursion and Leak Analysis Program 5(RELAP5), with the implementation of sodium–potassium eutectic alloy(NaK-78) properties and heat transfer correlations, is adopted to analyze the thermal–hydraulic characteristics of the space nuclear reactor TOPAZ-Ⅱ.A RELAP5 model including thermionic fuel elements(TFEs), reactor core, radiator, coolant loop, and volume accumulator is established. The temperature reactivity feedback effects of the fuel, TFE emitter, TFE collector,moderator, and reactivity insertion effects of the control drums and safety drums are considered. To benchmark the integrated TOPAZ-Ⅱ system model, an electrical ground test of the fully integrated TOPAZ-Ⅱ system, the V-71 unit,is simulated and analyzed. The calculated coolant temperature and system pressure are in acceptable agreement with the experimental data for the maximum relative errors of 8 and 10%, respectively. The detailed thermal–hydraulic characteristics of TOPAZ-Ⅱ are then simulated and analyzed at the steady state. The calculation results agree well with the design values. The current work provides a solid foundation for space reactor design and transient analysis in the future.

关键词： Space nuclear reactor TOPAZ-Ⅱ Thermal–hydraulic analysis RELAP5 modification

Nanograting-Based Dynamic Structural Colors Using Heterogeneous Materials

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NANO-MICRO LETTERS 2025年第1期17卷 1-14页

作者： Wang, Jingang Yu, Haibo zheng, Jianchen Zhang, Yuzhao Guo, Hongji qiu, Ye Wang, Xiaoduo Yang, Yongliang Liu, Lianqing Chinese Acad Sci Shenyang Inst Automat State Key Lab Robot Shenyang 110016 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

A 2.5-dimensional dynamic structural color based on nanogratings of heterogeneous materials was proposed by interweaving a pH-responsive hydrogel with IP-L *** nanogrid structures exhibit brilliant tuneable structural color, high sensitivity, and ultrafast recovery speeds in response to *** 4D printing-based grayscale design approach was proposed for the patterned encoding and array printing of dynamic structural colors, promoting their application in patterned printing, information encryption, and microfluidic chip sensing. Dynamic structural colors can change in response to different environmental stimuli. This ability remains effective even when the size of the species responsible for the structural color is reduced to a few micrometers, providing a promising sensing mechanism for solving microenvironmental sensing problems in micro-robotics and microfluidics. However, the lack of dynamic structural colors that can encode rapidly, easily integrate, and accurately reflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensional dynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogel with an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollen state, resulting in pH-tuned structural colors at a 45 degrees incidence. Moreover, the patterned encoding and array printing of dynamic structural colors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamic structural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.

关键词： Dynamic structural colors Four-dimensional printing pH-responsive Nanogrid Heterogeneous materials

有为政府与有效市场下的我国职业教育治理:理论逻辑与实践路径

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高校教育管理 2025年第1期19卷 62-73页

作者：李政邱懿华东师范大学职业教育与成人教育研究所上海200062 中华人民共和国教育部职业教育与成人教育司北京100816 北京大学教育学院北京100871

政府与市场的关系是职业教育内外部治理关系的核心,先后经历了政府主导论、市场基础论、有为政府与有效市场论的演变。在有为政府与有效市场的关系形塑下,职业教育治理改革应实现三大转变,即政府治理方式应从事后响应转变为事前布局,职... 详细信息

政府与市场的关系是职业教育内外部治理关系的核心,先后经历了政府主导论、市场基础论、有为政府与有效市场论的演变。在有为政府与有效市场的关系形塑下,职业教育治理改革应实现三大转变,即政府治理方式应从事后响应转变为事前布局,职业院校治理角色应从代理主体转变为改革先锋,市场主体参与治理的动机应从短期利益转变为战略投资。政府、职业院校和市场的关系应由单向的“影响回应”关系转变为双向的“并行互动”关系。当前,我国政府参与职业教育治理的权责边界不清,职业院校办学自主权无法满足发展需求,市场主体参与职业教育缺乏战略自觉。为此,我国应加强各级政府的政策协作,提升政府政策的精准度和前瞻性;优化职业院校组织定位和内部治理模式,提升学校治理的灵活性和有效性;深度分析企业发展的外部条件和内部需求,提升企业发展的积极性和适应性。

关键词：职业教育治理有为政府有效市场全面深化改革办学自主权

An investigation of flow characteristics and critical heat flux in vertical upward round tube

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Nuclear Science and Techniques 2006年第3期17卷 170-176页

作者： FAN Pu qiu sui-zheng JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China

Prediction of critical heat flux (CHF) in annular flow is important for the safety of once - through steam generator and the reactor core under accident conditions. The dryout in annular flow occurs at the point where the film is depleted due to entrainment, deposition, and evaporation. The film thickness, film mass flow rate along axial distribution, and CHF are calculated in vertical upward round tube on the basis of a separated flow model of annular flow. The theoretical CHF values are higher than those derived from experimental data, with error being within 30%.

关键词：环流临界热通量沉积挟带核反应堆工程

An Analytical Model Based on the Theory of Constant Heat Flux Ratio Across the Frozen Layer for Solving Planar, Cylindrical and Spherical Freezing Problems

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Journal of Thermal Science 2004年第2期13卷 155-162页

作者： sui Lin zheng Jiang Department of Mechanical and Industrial Engineering Concordia University Montreal Canada Flomerics Inc. Southborough USA

The purpose of the paper is to establish a theory of the constant heat flux ratio across the frozen layer based on the dimensional analysis of the system equations describing the freezing processes. An analytical model is then developed, utilizing this theory, for solving the planar, cylindrical and spherical freezing problems with both inward and outward freezing. As there is no exact solution available for the cylindrical and spherical freezing processes, the temperature distribution in the planar solidification obtained from the model is compared with the exact solution. They are in excellent agreement. For the cylindrical and spherical freezing, the complete inward solidification times calculated by the model are compared with those obtained from references. The results are in good agreement. The great advantage of the proposed model is its simplicity and is sufficiently accurate for most practical

关键词： analytical planar cylindrical spherical solidification theory constant heat flux ratio.

Analysis of flow instabilities in forced-convection steam generator

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Nuclear Science and Techniques 2006年第3期17卷 185-192页

作者： WU Ge-Ping qiu sui-zheng SU Guang-Hui JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇ an 710049 China

Because of the practical importance of two-phase instabilities, substantial efforts have been made to date to understand the physical phenomena governing such instabilities and to develop computational tools to model the dynamics. The purpose of this study is to present a numerical model for the analysis of flow-induced instabilities in forced-convection steam generator. The model is based on the assumption of homogeneous two-phase flow and ther- modynamic equilibrium of the phases. The thermal capacity of the heater wall has been included in the analysis. The model is used to analyze the flow instabilities in the steam generator and to study the effects of system pressure, mass flux, inlet temperature and inlet/outlet restriction, gap size, the ratio of do / di, and the ratio of qi / qo on the system be- havior.

关键词：蒸汽发生器强迫对流流动不稳定性双相不稳定性

Theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor

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Nuclear Science and Techniques 2006年第5期17卷 314-320页

作者： GOU Jun-Li qiu sui-zheng SU Guang-Hui JIA Dou-Nan State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China

This article presents a theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor. Through numerically solving the one-dimensional steady-state single-phase conservative equations for the primary circuit and the steady-state two-phase drift-flux conservative equations for the secondary side of the steam generator, the natural circulation characteristics were studied. On the basis of the pre- liminary calculation analysis, it was found that natural circulation mass flow rate was proportional to the exponential function of the power and that the value of the exponent is related to the operating conditions of the secondary side of the steam generator. The higher the outlet pressure of the secondary side of the steam generator, the higher the pri- mary natural circulation mass flow rate. The larger height difference between the core center and the steam generator center is favorable for the heat removal capacity of the natural circulation.

关键词：核反应堆压水堆稳态自然循环高度差理论研究

Evaluation of high-temperature tensile behavior for metal foils by a novel resistance heating assisted tensile testing system using samples with optimized structures

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Journal of Materials Science & Technology 2021年第35期94卷 216-229页

作者： qiu zheng Tsuyoshi Furushima Department of Mechanical and Biofunctional Systems Institute of Industrial ScienceThe University of Tokyo4-6-1 KomabaMeguro 153-8505TokyoJapan

To evaluate the tensile behavior of metal foils by resistance heating(RH)assisted tensile testing system accurately,this study proposed to embed a digital image correlation(DIC)system with laser speckles for the measurement of full-field strain ***,the sample structures were optimized to achieve uniform temperature and strain *** infrared camera was used to monitor the temperature *** samples instead of dog-bone shaped samples were proposed.A model for calculating the temperature distribution was established to optimize the sample *** parameters that influence the temperature distribution and tensile behavior were *** results,compared to the strain measured by a non-contact extensometer,the maximum deviation of the strain measured by DIC was less than 6%when the nominal strain was larger than *** is confirmed that the proposed tensile testing system is reliable for measuring the temperature and full-field strain *** shape influenced temperature distributions of smaller samples while it almost had no influence on the temperature distributions of larger *** temperature difference was not affected by the material type but by the sample *** proposed rectangular shape was validated to be feasible for RH assisted tensile *** sample length was successfully optimized for a more uniform temperature distribution by the established *** the tensile deformation was not influenced by the sample shape,the temperature distribution resulted in a non-uniform strain distribution before achieving ultimate tensile *** effective sample length between two clamping jigs contributed to a more uniform temperature distribution and material deformation.A more accurate evaluation of high-temperature tensile behavior for metal foils can be achieved by the proposed RH assisted tensile testing system using rectangular samples with an optimized structure.

关键词： High temperature Metal foil Resistance heating Sample structure Tensile behavior

A direct probabilistic approach to solve state equations for nonlinear systems under random excitation

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Acta Mechanica Sinica 2016年第5期32卷 941-958页

作者： zheng Lv Zhiping qiu Institute of Solid Mechanics Beihang University

In this paper, a direct probabilistic approach（DPA） is presented to formulate and solve moment equations for nonlinear systems excited by environmental loads that can be either a stationary or nonstationary random *** proposed method has the advantage of obtaining the response＇s moments directly from the initial conditions and statistical characteristics of the corresponding external excitations. First, the response＇s moment equations are directly derived based on a DPA, which is completely independent of the It？/filtering approach since no specific assumptions regarding the correlation structure of excitation are *** solving them under Gaussian closure, the response＇s moments can be obtained. Subsequently, a multiscale algorithm for the numerical solution of moment equations is exploited to improve computational efficiency and avoid much wall-clock time. Finally, a comparison of the results with Monte Carlo（MC） simulation gives good ***, the advantage of the multiscale algorithm in terms of efficiency is also demonstrated by an engineering example.

关键词： Direct probabilistic approach Nonlinear dynamic system Nonstationary random process Response’s moments Multiscale algorithm