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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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Human-induced pluripotent stem cell-derived neural stem cell exosomes improve blood-brain barrier function after intracerebral hemorrhage by activating astrocytes via PI3K/AKT/MCP-1 axis

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Neural Regeneration Research 2025年第2期20卷 518-532页

作者： Conglin wang Fangyuan Cheng Zhaoli Han Bo Yan Pan Liao Zhenyu Yin Xintong Ge Dai Li Rongrong zhong Qiang Liu Fanglian Chen Ping Lei Department of Geriatrics Tianjin Medical University General HospitalTianjinChina School of Medicine Nankai UniversityTianjinChina Tianjin Neurological Institute TianjinChina

Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor ***-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)have shown potential for brain injury repair in central nervous system *** this study,we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying *** results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits,enhanced blood-brain barrier integrity,and reduced leukocyte infiltration in a mouse model of intracerebral ***,hiPSC-NSC-Exos decreased immune cell infiltration,activated astrocytes,and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1,macrophage inflammatory protein-1α,and tumor necrosis factor-αpost-intracerebral hemorrhage,thereby improving the inflammatory *** sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion,thereby improving blood-brain barrier *** with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these *** summary,our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity,in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.

关键词： AKT astrocyte blood-brain barrier cerebral edema exosomes human-induced pluripotent stem cells intracerebral hemorrhage neural stem cells neuroinflammation PI3K

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Chiral phosphoramidite ligand-modulated palladium auto-tandem catalysis for asymmetric dehydrogenative dienylation of imines with α-alkenes

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Science China Chemistry 2025年

作者： zhong-Sheng Nong Hao-Fan Qian Ying-Chun Chen Pu-Sheng wang Liu-Zhu Gong Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Key Laboratory of Drug Targeting and Drug Delivery System (Sichuan University) Ministry of Education and Sichuan Research Center for Drug Precision Industrial Technology West China School of Pharmacy Sichuan University School of Materials and Chemistry Southwest University of Science and Technology

The development of efficient processes allowing rapid access to complex chiral molecules from easily available alkenes is a long-term pursuit in the synthetic chemistry community. Transition metal-catalyzed asymmetric functionalization of allylic C–H bond represents a unique alternative toward this goal. However, enantioselective dehydrogenative transformation of olefins to value-added optically enriched molecules remains yet to be discovered. Here, we report a highly enantioselective dehydrogenative dienylation of imines with unactivated α-alkenes driven by the synergistic action of palladium complex and carboxylic acid. Chiral phosphoramidite ligands turned out to be superior in modulating the performance of palladium autotandem catalysis and allowed a broad range of α-alkenes and imines to be transformed into chiral dienylamines. Mechanistic studies suggest that the dienes could be in situ generated from α-alkenes through a palladium(0)-mediated dehydrogenative process in the presence of excess benzoquinone oxidants, and then participated in the Pd-chiral phosphoramidite-catalyzed intermolecular vinylogous-type addition to the imines activated by the carboxylic acid co-catalyst. Notably, the second β-H elimination occurring in the dienylation event might be the turnover-limiting step.

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Dissipation-free approach for realizing non-Hermitian dynamics in a superconducting circuit

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Science China(Physics,Mechanics & Astronomy) 2025年

作者： Yi-Hao Kang Yang xiao Yu wang Qi-Ping Su Chui-Ping Yang School of Physics Hangzhou Normal University Fujian Key Laboratory of Quantum Information and Quantum Optics Fuzhou University Department of Physics Fuzhou University

Non-Hermitian dynamics exhibits a wealth of surprising and potentially useful phenomena. However, it is typically realized by coupling a system with thermal reservoirs, which makes the system suffer from thermal fluctuations associated with the dissipation. Here, we propose a dissipation-free approach to realize non-Hermitian dynamics using a superconducting circuit composed of two resonators and a superconducting qutrit. The non-Hermiticity arises in the dynamical matrix for the evolution of the two resonators in the Heisenberg picture, via a photon-number non-conserved dynamics. The energy spectrum of the non-Hermitian dynamical matrix can be retrieved by measuring the state of the two resonators, and a phase transition of the energy spectrum can be observed by varying the control parameters. In the realization of the non-Hermitian dynamics, the dissipation of the system and the post-selection are not required. Thus, the approach is implemented in a deterministic way, and the reservoir-induced noise is suppressed. Numerical simulations indicate that the energy spectrum of the non-Hermitian dynamical matrix obtained via the measurement of the resonators is in accordance with the theoretical prediction. Moreover, we demonstrate the parity discrimination for the state of two four-level qudits as an application, exhibiting the potential of the non-Hermitian dynamics in the field of quantum measurement. This work opens a new avenue for the realization of non-Hermitian dynamics and may have a significant implication in exploring the non-Hermitian phenomena.

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一测多评法同时测定清解颗粒中3种成分

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中成药 2019年第9期41卷 2052-2057页

作者：唐林肖望重黄莉雷昌夏新华湖南中医药大学第一附属医院湖南长沙410007 中药粉体与创新药物省部共建国家重点实验室培育基地湖南长沙410208 湖南中医药大学药学院湖南长沙410208

目的建立一测多评法同时测定清解颗粒(苦杏仁、防风、石膏等)中3种成分的含有量。方法该药物甲醇提取液的分析采用依利特C18色谱柱(4.6 mm×250 mm,5μm);流动相甲醇-乙腈-0.1%冰醋酸,梯度洗脱;体积流量1 mL/min;检测波长210、254 nm;柱... 详细信息

目的建立一测多评法同时测定清解颗粒(苦杏仁、防风、石膏等)中3种成分的含有量。方法该药物甲醇提取液的分析采用依利特C18色谱柱(4.6 mm×250 mm,5μm);流动相甲醇-乙腈-0.1%冰醋酸,梯度洗脱;体积流量1 mL/min;检测波长210、254 nm;柱温30℃。以苦杏仁苷为内标,建立其他2种成分的相对校正因子,测定含有量。结果苦杏仁苷、升麻素苷、5-O-甲基维斯阿米醇苷分别在37.08~1 236、22.4~748、11.88~396μg/mL范围内线性关系良好(R2≥0.999 9),平均加样回收率102.17%、101.12%、104.73%,RSD 1.85%、1.74%、2.12%。一测多评法所得结果与外标法接近。结论该方法准确可靠,可用于清解颗粒的质量控制。

关键词：清解颗粒苦杏仁苷升麻素苷 5-O-甲基维斯阿米醇苷一测多评

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Unlocking the stable interface in aqueous zinc-ion battery with multifunctional xylose-based electrolyte additives

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Journal of Energy Chemistry 2025年第1期100卷 770-778页

作者： xiaoqin Li Jian Xiang Lu Qiu xiaohan Chen Yinkun Zhao Yujue wang Qu Yue Taotao Gao Wenlong Liu Dan xiao Zhaoyu Jin Panpan Li Institute for Advanced Study Chengdu University School of Mechanical Engineering Chengdu University College of Food and Biological Engineering Chengdu University Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China College of Materials Science and Engineering Sichuan University

The growth of dendrites and the side reactions occurring at the Zn anode pose significant challenges to the commercialization of aqueous Zn-ion batteries（AZIBs）. These challenges arise from the inherent conflict between mass transfer and electrochemical kinetics. In this study, we propose the use of a multifunctional electrolyte additive based on the xylose（Xylo） molecule to address these issues by modulating the solvation structure and electrode/electrolyte interface, thereby stabilizing the Zn anode. The introduction of the additive alters the solvation structure, creating steric hindrance that impedes charge transfer and then reduces electrochemical kinetics. Furthermore, in-situ analyses demonstrate that the reconstructed electrode/electrolyte interface facilitates stable and rapid Zn2+ion migration and suppresses corrosion and hydrogen evolution reactions. As a result, symmetric cells incorporating the Xylo additive exhibit significantly enhanced reversibility during the Zn plating/stripping process, with an impressively long lifespan of up to 1986 h, compared to cells using pure ZnSO4electrolyte. When combined with a polyaniline cathode, the full cells demonstrate improved capacity and long-term cyclic stability. This work offers an effective direction for improving the stability of Zn anode via electrolyte design, as well as highperformance AZIBs.

关键词： Solvation

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云南萝芙木与催吐萝芙木HPLC指纹图谱建立及利血平测定

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中成药 2020年第8期42卷 2107-2112页

作者：唐林肖望重刘检龙红萍吴笛王宇红湖南中医药大学第一附属医院湖南长沙410007 中药粉体与创新药物省部共建国家重点实验室培育基地湖南长沙410208

目的建立萝芙木属药材HPLC指纹图谱,并测定利血平的含有量。方法样品80%乙醇提取物的分析采用C18色谱柱(250 mm×4.6 mm,5μm);流动相乙腈-0.05%三乙胺溶液,梯度洗脱;检测波长280 nm。采用UPLC-Q-TOF进行色谱峰组分鉴定。通过相似度评... 详细信息

目的建立萝芙木属药材HPLC指纹图谱,并测定利血平的含有量。方法样品80%乙醇提取物的分析采用C18色谱柱(250 mm×4.6 mm,5μm);流动相乙腈-0.05%三乙胺溶液,梯度洗脱;检测波长280 nm。采用UPLC-Q-TOF进行色谱峰组分鉴定。通过相似度评价并结合聚类分析、主成分分析及正交偏最小二乘法-判别分析对云南萝芙木与催吐萝芙木的总体质量评价。结果15批样品HPLC指纹图谱中有15个共有峰,对其中11个共有峰进行成分鉴别。相似度0.83~0.97,表明该药材总体质量较为稳定;但通过模式识别技术均发现不同批次药材质量之间存在一定的差异,且主要分为2类,最后进一步采用正交偏最小二乘法-判别分析筛选出云南萝芙木与催吐萝芙木质量差异的2种主要成分,分别为利血平、萝芙木碱。结论该方法科学、准确、可靠且简便,可系统、全面地评价萝芙木属药材的质量。

关键词：云南萝芙木催吐萝芙木指纹图谱 HPLC 化学模式识别

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Formation and evolution of supercritical geofluid

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Science China Earth Sciences 2025年第1期68卷 39-51页

作者： Huaiwei NI Yilin xiao xiaolin XIONG Xiandong LIU Chunxiao GAO Yi-Xiang CHEN Yunguo LI Wan-Cai LI Xuan GUO Yang-Yang wang Dong-Bo TAN Li ZHANG State Key Laboratory of Lithospheric and Environmental Coevolution University of Science and Technology of China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of China Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Earth Sciences and Engineering Nanjing University State Key Lab of Superhard Materials Jilin University

In this work, we provide a comprehensive review on the formation, evolution, properties, and effects of supercritical geofluid. In Earth's interior, enhanced miscibility between H2O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H2O and silicate *** formation of supercritical geofluid in magmatic-hydrothermal systems, typified by pegmatite system, is governed by meltfluid critical curve. The formation of supercritical geofluid in metamorphic systems, typified by subducted slab, is governed by the second critical end point. Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths, but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth. A major presence of both H2O and depolymerized structural units（monomers, dimers, etc.） endows supercritical geofluid with unique physical properties including low density, low elastic moduli, low viscosity, high diffusivity,and high electrical conductivity. Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements. The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts, and this could give an explanation of the oxidation of arc magmas. Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network. Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid. Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab, and can be linked with intermediate-focus earthquakes. Supercritical geofluid may have played a crucial role in the formation of pe

关键词： Supercritical geofluid Miscibility Subduction zone Pegmatite

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浅谈采取新举措打造新人才

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云南冶金 2009年第4期38卷 70-72页

作者：马明仙钟晓王云南锡业集团有限责任公司研究设计院云南个旧661000

在学习科学理论和总结实践经验的基础上,理论与实际紧密结合,就采取新举措打造新人才的关键环节、重要因素和重要途径进行了论述,具有一定理论性、可借鉴性和可操作性。

关键词：人才创新之本新举措新人才

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Specific staining and precise killing of cancer cells through fusion of pharmaceutical chemistry and π-bridge effect design philosophy

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Science China Chemistry 2025年

作者： Qiong Liu Qiyun Deng Changxu Zhu Kongqi Chen Lidan Chen Zhaohui Sun Ben zhong Tang Zhiming wang AIE Institute Center for Aggregation-Induced Emission State Key Laboratory of Luminescent Materials and Devices Key Laboratory of Luminescence from Molecular Aggregates of Guangdong Province South China University of Technology Department of Laboratory Medicine General Hospital of Southern Theater Command School of Life Sciences The Chinese University of Hong Kong Shenzhen Institute of Aggregate Science and Technology School of Science and Engineering The Chinese University of Hong Kong HKUST-Shenzhen Research Institute

The development of an advanced phototheranostic platform that combines imaging and therapy in a single agent is an appealing yet challenging *** this study,we successfully constructed three novel fluorescent probes by leveraging pharmaceutical chemistry and the design philosophy of theπ-bridge *** a systematic comparative analysis of their fluorescence properties,water solubility,molecular conformation,and electrostatic potential,we revealed the fundamental principles governing the optical behavior and biological selectivity of these ***,the probe TPhIQ-CNTh demonstrated extended fluorescence in the near-infrared region,a significant aggregation-induced emission (AIE) effect,and the ability to distinguish tumor cells from normal ***,it efficiently generated reactive oxygen species (ROS) and specifically labeled lipid droplets,enabling the precise staining and killing of cancer *** study presents a practical strategy for designing precise tumor treatments that integrate efficient imaging-guided photodynamic therapy (PDT) by harnessing the unique properties of AIE materials.

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