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Development of a general circumferentially nonuniform heat transfer fuel rod model for subchannel analysis and application to helical fuel rods

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Science China Technological Sciences 2025年

作者： Junsen FU Junlong LI Xiaowen WANG qi zhang Yao XIAO Hanyang GU School of Mechanical Engineering Shanghai Jiao Tong University Key Laboratory of Nuclear Power Systems and Equipment of the Ministry of Education Shanghai Jiao Tong University National Key Laboratory of Nuclear Reactor Technology Nuclear Power Institute of China State Key Laboratory of Nuclear Power Safety Technology and Equipment Shanghai Jiao Tong University

The subchannel analysis method is one of the most crucial transient safety analysis methods in the thermal design of nuclear reactors. The nonuniformity of circumferential heat transfer is slight in conventional pressurized water reactor (PWR)cores, but it is significant in advanced reactors with wire-wrapped or helical fuel rods. Predicting circumferentially nonuniform heat transfer behavior can be challenging owing to the complex geometry of helical fuel rods. In this study, a general circumferentially nonuniform heat transfer fuel rod (GCNF) model is developed to predict the fuel central temperature and circumferential heat flux and wall temperature. This model incorporates a refined two-dimensional fuel conduction model and circumferential nonuniform shape factor, addressing the dual factors contributing to the circumferential nonuniformity of helical fuel rods. An empirical correlation for the nonuniform shape factor is developed based on the computational fluid dynamics (CFD) results, and it is implemented to the subchannel code. The newly developed model is applied to a helical fuel annulus and validated by comparing the prediction results with CFD data. The maximum wall temperature predicted by the code is 1.15°C lower than the value calculated through CFD. In terms of the heat flux, the maximum value at the inner corner is22 kW lower than that obtained from the CFD prediction. The accurate prediction of circumferentially nonuniform heat transfer in helical fuel, concerning the surface heat flux and cladding temperature, addresses existing shortcomings in helical fuel subchannel analysis methods. Additionally, the capability to predict the fuel central temperature is essential for the safety analysis to determine whether fuel rods are melting. The generality of the model framework allows it to be used for the prediction of circumferential nonuniform heat transfer behavior in other types of fuel assemblies.

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Synthesis of chiral phosphine derivatives through a copper（I）-catalyzed desymmetric SNAr reaction

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Science China Chemistry 2025年

作者： Shuai zhang Pei-Zhi Liu Yan-Bo Li qi zhang Jun-Zhao Xiao Yi-Fan Wang Tian-Yu Wei Jia-Wei Jiang Ye Wang qian Peng Liang Yin Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences State Key Laboratory of Elemento-Organic Chemistry and Tianjin Key Laboratory of Biosensing and Molecular Recognition College of Chemistry Frontiers Science Center for New Organic Matter Nankai University Haihe Laboratory of Sustainable Chemical Transformations

Axially chiral phosphines are a class of extremely important ligands in asymmetric catalysis. Herein, an unprecedented copper（I）-catalyzed asymmetric SNAr reaction with HP（S）R2is uncovered, which delivers a series of axially chiral phosphine derivatives in high yields with excellent enantioselectivity. Furthermore, the diastereoselective reaction with the kinetic resolution of racemic HP（S）ArR proceeds smoothly, providing the products with moderate diastereoselectivity and excellent enantioselectivity. Control experiments indicate that HP（S）Ph2is much more active than HPPh2and HP（O）Ph2as the pronucleophile in the present reaction. It is found that the SNAr reaction （the first SNAr） proceeds in a desymmetric manner, providing the desired chiral products while a continued SNAr reaction （the second SNAr） slightly occurs in a kinetic resolution manner in the present catalytic system, which enhances the ee of the desired chiral products. DFTcalculations support a concerted reaction pathway rather than a step-wise mechanism. Finally, axially chiral olefin-phosphines produced by the present method work as suitable ligands in Pdcatalyzed asymmetric allylic substitution with C-, N-, and O-nucleophiles and Rh-catalyzed asymmetric addition of arylboronic acid to benzil.

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生成式人工智能应用场景下个人信息保护的法律风险及应对

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太原学院学报（社会科学版） 2025年第1期26卷 58-70页

作者：张淇山西财经大学法学院山西太原030006

数据已成为新的产权要素和产业基础,而具备了一定理性能力的生成式人工智能ChatGPT在大数据喂养、人为数据标识处理和信息再输出三个层次对个人信息权益构成了新的侵权范式。尽管《个人信息保护法》《网络安全法》等法律规范已确立起一... 详细信息

数据已成为新的产权要素和产业基础,而具备了一定理性能力的生成式人工智能ChatGPT在大数据喂养、人为数据标识处理和信息再输出三个层次对个人信息权益构成了新的侵权范式。尽管《个人信息保护法》《网络安全法》等法律规范已确立起一系列个人信息保护手段,但在生成式人工智能服务与应用端仍面临着解释和适用上的难题。为此,我国需要在保障个人信息权益的前提下鼓励发展人工智能技术——在总体上要树立起基于风险的个人信息保护原则,并尝试以“风险预知—解构—化解”为基本路径,在微观上优化“知情-同意”规则,以“设计保护”原则强化企业内部自治,并灵活调整侵权责任追究机制。

关键词：《个人信息保护法》 ChatGPT 生成式人工智能风险控制

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机电扫描雷达波束指向控制方法

电子信息对抗技术 2025年第1期40卷 90-94页

作者：张祺中国电子科技集团公司第二十九研究所成都610036

相控阵雷达配备伺服机构,可显著扩大雷达的作用空域范围。当伺服机构带动天线阵面在全空域工作时,需要电扫系统配合完成波束指向控制。在机扫、电扫相结合阵面的波束控制、跟踪算法中,为了避免复杂坐标变换,提出了一种由伺服转角、阵面... 详细信息

相控阵雷达配备伺服机构,可显著扩大雷达的作用空域范围。当伺服机构带动天线阵面在全空域工作时,需要电扫系统配合完成波束指向控制。在机扫、电扫相结合阵面的波束控制、跟踪算法中,为了避免复杂坐标变换,提出了一种由伺服转角、阵面倾斜角、目标方位角和俯仰角计算波束控制码的方法。由该计算方法得出的波束控制码,通过一种快速分布式控制方法,经济高效地控制阵面波束指向。和已有方法对比,该计算方法可以通过机扫参数和目标的雷达站心坐标,直接计算出电扫波束控制码,无需再进行繁琐的坐标变换。另外,快速分布式波束控制方法可以减少控制总线数量和降低阵面复杂度,缩短电扫流水节拍时间。因此,在更短的机扫驻留时间内,可以覆盖该驻留空域中更多的目标,提高雷达系统的效率。

关键词：相控阵机电扫描雷达波束指向控制雷达坐标系

Deep eutectic solvent inclusions for high-k composite dielectric elastomers

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Frontiers of Chemical Science and Engineering 2022年第6期16卷 996-1002页

作者： Changgeng zhang qi zhang School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhen 518172China

Recent advances in novel electroactive devices have placed new requirements on material ***-performance dielectric elastomers with good mechanical stretchability and high dielectric constant are under high ***,the current strategy for fabricating these materials suffers from high cost or low thermal stability,which greatly hinders large-scale industrial ***,we have successfully developed a novel strategy for improving the dielectric constant of polymeric elastomers via deep eutectic solvent inclusion by taking advantage of the low cost,convenient and environmentally benign synthesis process and high ionic conductivity from deep eutectic *** as-prepared composite elastomers showed good stretchability and a greatly enhanced dielectric constant with a negligible increase in dielectric ***,we have proven the universality of our strategy by using different types of deep eutectic *** is believed that low-cost,easy-synthesis and environmentally friendly deep eutectic solvents including composite elastomers are highly suitable for large-scale industrial production and can greatly broaden the application fields of dielectric elastomers.

关键词： composite materials deep eutectic solvent dielectric elastomer high dielectric constant

Certificateless threshold signature from lattice

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Digital Communications and Networks 2024年第4期10卷 965-972页

作者： Huifang Yu qi zhang School of Cyberspace Security Xi'an University of Posts and TelecommunicationsXi'anChina

Threshold signature has been widely used in electronic wills,electronic elections,cloud computing,secure multiparty computation and other *** now,certificateless threshold signature schemes are all based on traditional mathematic theory,so they cannot resist quantum computing *** view of this,we combine the advantages of lattice-based cryptosystem and certificateless cryptosystem to construct a certificateless threshold signature from lattice(LCLTS)that is efficient and resistant to quantum algorithm *** has the threshold characteristics and can resist the quantum computing attacks,and the analysis shows that it is unforgeable against the adaptive Chosen-Message Attacks(UF-CMA)with the difficulty of Inhomogeneous Small Integer Solution(ISIS)*** addition,LCLTS solves the problems of the certificate management through key escrow.

关键词： Lattice Threshold signature Inhomogeneous small integer solution Certificateless public key Lattice sampling technique

Some Remarks on One-dimensional Functions and Their Riemann–Liouville Fractional Calculus

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Acta Mathematica Sinica,English Series 2014年第3期30卷 517-524页

作者： qi zhang Faculty of Science Nanjing University of Aeronautics and Astronautics

A one-dimensional continuous function of unbounded variation on [0, 1] has been con- structed. The length of its graph is infinite, while part＂ of this function displays fractal features. The Box dimension of its Rie... 详细信息

关键词： Box dimension Hausdorff dimension fractional integral fractal function

脊柱手术机器人治疗脊柱疾病的研究发展趋势及热点剖析

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中国组织工程研究 2025年第21期29卷 4612-4620页

作者：牛艳艳张琦范明星首都医科大学附属北京积水潭医院医学期刊中心北京市100035 首都医科大学附属北京积水潭医院脊柱外科北京市100035

背景:近年来在脊柱外科领域,手术机器人的应用已成为研究热点,但目前中国尚缺乏脊柱手术机器人的的文献可视化分析相关研究。目的:对脊柱手术机器人治疗脊柱疾病的研究热点进行文献可视化分析,以期为中国脊柱手术机器人的研究和发展提... 详细信息

背景:近年来在脊柱外科领域,手术机器人的应用已成为研究热点,但目前中国尚缺乏脊柱手术机器人的的文献可视化分析相关研究。目的:对脊柱手术机器人治疗脊柱疾病的研究热点进行文献可视化分析,以期为中国脊柱手术机器人的研究和发展提供有益的参考。方法:在Web of Science核心集数据库中检索脊柱手术机器人治疗脊柱疾病的相关文献,最终纳入900篇文献。采用VOSviewer 1.6.19软件对纳入文献的发文量、期刊、机构、国家、关键词、共被引文献和高被引文献进行可视化分析。结果与结论:(1)脊柱手术机器人治疗脊柱疾病研究领域的文献呈逐年上升趋势,尤其在2023年达到了发文量的高峰。美国、中国和德国是该领域的研究热点国家。中国国家自然科学基金是该领域的主要资助基金。(2)中国北京积水潭医院和美国特殊外科医院在该领域的研究具有较高的发文量。(3)《World Neurosurgery》《Spine》和《Operative Neurosurgery》是该领域的主要发文期刊。(4)关键词分析显示,研究主要集中在机器人辅助脊柱手术的准确性、微创手术、机器人脊柱手术和导航技术等方面。(5)文献共被引分析结果显示了机器人辅助技术在脊柱手术中具有显著优势,与传统手术相比,脊柱手术机器人如ROSA?Spine,ExcelsiusGPS,Mazor X及TiRobot等,具有高精度导航、精确椎弓根螺钉置入及实时反馈等优点,它们通过减少手术中X射线辐射暴露,降低患者并发症风险,提高手术成功率,显示出其在脊柱外科领域的应用前景。(6)尽管如此,相关技术的应用和精确度仍需不断积累经验以提高;机器人手术技术在降低手术辐射暴露和提高手术精度方面显示出成本效益,但还需深入探讨其在椎弓根螺钉置入过程中的精确度、手术时间影响及经济效益。(7)2021-2024年的高被引文献分析结果进一步显示,目前该领域最新研究热点主要集中在虚拟现实和增强现实技术的应用、机器人辅助椎弓根螺钉置入的准确性提升以及导航机器人脊柱手术平台的应用等。例如,通过创新技术如有机电化学神经元为脑机接口、假肢和智能软机器人技术提供了新的集成方案。同时,虚拟现实和增强现实技术在脊柱畸形矫正等领域展示了广泛应用前景。

关键词：脊柱脊柱手术机器人机器人辅助技术脊柱手术椎弓根螺钉准确性导航并发症脊柱畸形

Shear-induced Precursors of Fibrillar Crystals of Poly(butene-1):A Rheological Study

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Chinese Journal of Polymer Science 2022年第6期40卷 618-623页

作者： Jia-qi zhang Quan Chen State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China

Strong preshear flow stretches poly(butene-1)chains to form flow-induced precursors of fibrillar *** formation leads to further growth of shear/normal stress after the stress reaches the steady *** this study,stress relaxation measurements are performed after intervals of a strong flow during which the precursors *** small-angle X-ray scattering(SAXS)and wide-angle X-ray diffraction(WAXD)measurements are conducted to characterize the crystalline structure formed after the preshear and relaxation processes,each of different periods.A combination of the stress relaxation and scattering results reveal that for the precursors formed within 5 s,the stress can fully relax and the orientation of the subsequent crystals(formed upon quenching the sample at different stress levels)decays gradually with the *** comparison,for those precursors formed after 5 s,the stress hardly relaxes during~10^(4) s,and the orientation of the subsequent crystals hardly decays,suggesting that the precursors have been somehow stabilized during the *** features have been discussed with respect to the percolation of the precursors to form a reversible network.

关键词： PB-1 Rheology Precursor Fibrillar crystal