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Commissioning of a radiofrequency quadrupole cooler‑buncher for collinear laser spectroscopy
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作者 Yin‑Shen Liu Han‑Rui Hu +15 位作者 Xiao‑Fei Yang Wen‑Cong Mei Yang‑Fan Guo Zhou Yan Shao‑Jie Chen Shi‑Wei Bai Shu‑Jing Wang Yong‑Chao Liu peng zhang Dong‑Yang Chen Yan‑Lin Ye Qi‑Te Li Jie Yang Stephan Malbrunot‑Ettenauer Simon Lechner Carina Kanitz 《Nuclear Science and Techniques》 2026年第1期193-201,共9页
A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam qualit... A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup. 展开更多
关键词 Radiofrequency quadrupole cooler-buncher Collinear laser spectroscopy Hyperfine structure Time of flight
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教育数字化转型与教师数字素养提升研究 被引量:1
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作者 张捧 宋子琦 《教育教学研究前沿》 2025年第4期1-3,共3页
全球教育体系正经历由数字技术驱动的系统性变革,教师数字素养成为教育数字化转型的核心支撑。在此背景下,数字素养已经成为高校教师的必备素养之一。虽然近年来高校的教育数字化取得了一定进展,但仍然存在数据开发与应用等问题。因此,... 全球教育体系正经历由数字技术驱动的系统性变革,教师数字素养成为教育数字化转型的核心支撑。在此背景下,数字素养已经成为高校教师的必备素养之一。虽然近年来高校的教育数字化取得了一定进展,但仍然存在数据开发与应用等问题。因此,深入分析教师数字素养在教育数字化转型中的核心地位,研究教师数字素养提升的关键路径,对于提高教育生态具有重要意义。 展开更多
关键词 教育数字化转型 教师数字素养 数字素养提升
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基于Theodorsen理论的跨声速颤振非定常气动力建模 被引量:2
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作者 刘永平 张朋 +2 位作者 曾开春 余立 寇西平 《航空学报》 北大核心 2025年第12期207-225,共19页
提出了一种针对机翼俯仰和浮沉耦合颤振的跨声速非定常气动力建模方法,将经典的不可压Theodorsen理论扩展到跨声速非定常流。考虑跨声速流压缩效应和非定常下激波运动引起的升力线斜率和焦点变化,构造基于Theodorsen理论的跨声速修正函... 提出了一种针对机翼俯仰和浮沉耦合颤振的跨声速非定常气动力建模方法,将经典的不可压Theodorsen理论扩展到跨声速非定常流。考虑跨声速流压缩效应和非定常下激波运动引起的升力线斜率和焦点变化,构造基于Theodorsen理论的跨声速修正函数,建立非定常气动力模型,以捕捉跨声速流中非定常气动力幅值和相位的变化。使用Isogai机翼算例模型,对跨声速修正函数构建、修正函数和非定常气动力的特性、弹性轴的影响、颤振非线性特征等开展了研究。研究结果表明:修正函数能够捕捉跨声速流中翼面激波的振荡特性,非定常气动力的幅值减小和相位滞后;特定弹性轴下获取的修正函数参数值可以泛化到任意弹性轴状态;所提出的非定常建模方法能够准确表征跨声速气动力的非线性特性,实现高效准确的跨声速颤振特性预测。 展开更多
关键词 非定常气动力 Theodorsen理论 跨声速修正 颤振 俯仰和浮沉耦合
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共价有机框架中的组分工程用于定制光催化
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作者 邵毅宏 沈荣晨 +3 位作者 王松 李世杰 张鹏 李鑫 《物理化学学报》 北大核心 2025年第12期1-48,共48页
能源危机与环境恶化的危害日益严峻,亟需发展环境友好型可持续生产技术。将丰富的太阳能直接转化为化学能,被视为一种极具前景的绿色高效技术方案。在此过程中,光催化剂扮演着至关重要的角色。共价有机框架材料(COFs)作为一种通过共价... 能源危机与环境恶化的危害日益严峻,亟需发展环境友好型可持续生产技术。将丰富的太阳能直接转化为化学能,被视为一种极具前景的绿色高效技术方案。在此过程中,光催化剂扮演着至关重要的角色。共价有机框架材料(COFs)作为一种通过共价键连接的多孔材料,凭借其高比表面积、优异的结晶性和可调控的结构,展现出卓越的光催化潜力。本综述深入探讨了组分调控对提升COFs光催化性能的作用机制,涵盖调控光吸收、增加活性位点、促进激子解离以及改善载流子分离,并对相关计算模拟与机理表征方法进行了详细论述。更为重要的是,系统总结了组分调控的核心策略,包括杂原子工程、金属单原子工程、离子工程、官能团工程、供体-受体(D-A)分子工程、侧链工程、多组分工程、同分异构工程、共轭桥工程、单分子结工程和层间工程。此外,本文还详细阐述了这些策略在光催化析氢(H_(2))、过氧化氢(H_(2)O_(2))合成及二氧化碳(CO_(2))还原等领域的多样化改性策略与应用。最后,对COF基光催化技术当前面临的挑战及未来发展方向进行了前瞻性展望。 展开更多
关键词 共价有机框架 组分调控 光催化应用 工程和改性策略 激子解离
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Enhancing carbon sequestration and greenhouse gas mitigation in semiarid farmland:The promising role of biochar application with biodegradable film mulching 被引量:2
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作者 Jinwen Pang Zhonghong Tian +9 位作者 Mengjie zhang Yuhao Wang Tianxiang Qi Qilin zhang Enke Liu Weijun zhang Xiaolong Ren Zhikuan Jia Kadambot H.M.Siddique peng zhang 《Journal of Integrative Agriculture》 2025年第2期517-535,共19页
Long-term mulching has improved crop yields and farmland productivity in semiarid areas,but it has also increased greenhouse gas(GHG)emissions and depleted soil fertility.Biochar application has emerged as a promising... Long-term mulching has improved crop yields and farmland productivity in semiarid areas,but it has also increased greenhouse gas(GHG)emissions and depleted soil fertility.Biochar application has emerged as a promising solution for addressing these issues.In this study,we investigated the effects of four biochar application rates(no biochar(N)=0 t ha^(-1),low(L)=3 t ha^(-1),medium(M)=6 t ha^(-1),and high(H)=9 t ha^(-1))under film mulching and no mulching conditions over three growing seasons.We assessed the impacts on GHG emissions,soil organic carbon sequestration(SOCS),and maize yield to evaluate the productivity and sustainability of farmland ecosystems.Our results demonstrated that mulching increased maize yield(18.68-41.80%),total fixed C in straw(23.64%),grain(28.87%),and root(46.31%)biomass,and GHG emissions(CO_(2),10.78%;N_(2)O,3.41%),while reducing SOCS(6.57%)and GHG intensity(GHGI;13.61%).Under mulching,biochar application significantly increased maize yield(10.20%),total fixed C in straw(17.97%),grain(17.69%)and root(16.75%)biomass,and SOCS(4.78%).Moreover,it reduced the GHG emissions(CO_(2),3.09%;N_(2)O,6.36%)and GHGI(12.28%).These effects correlated with the biochar addition rate,with the optimal rate being 9.0 t ha^(-1).In conclusion,biochar application reduces CO_(2) and N_(2)O emissions,enhances CH_(4) absorption,and improves maize yield under film mulching.It also improves the soil carbon fixation capacity while mitigating the warming potential,making it a promising sustainable management method for mulched farmland in semiarid areas. 展开更多
关键词 BIOCHAR film mulching greenhouse gas emissions carbon sequestration
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Magnolol inhibits appetite and causes visceral fat loss through Growth/differentiation factor-15(GDF-15)by activating transcription factor 4-CCAAT enhancer binding proteinγ-mediated endoplasmic reticulum stress responses 被引量:1
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作者 Keru Cheng Yanyun Zhou +4 位作者 Yilong Hao Shengyun Wu Nanping Wang peng zhang Yinfang Wang 《Chinese Journal of Natural Medicines》 2025年第3期334-345,共12页
Magnolol,a compound extracted from Magnolia officinalis,demonstrates potential efficacy in addressing metabolic dysfunction and cardiovascular diseases.Its biological activities encompass anti-inflammatory,antioxidant... Magnolol,a compound extracted from Magnolia officinalis,demonstrates potential efficacy in addressing metabolic dysfunction and cardiovascular diseases.Its biological activities encompass anti-inflammatory,antioxidant,anticoagulant,and anti-diabetic effects.Growth/differentiation factor-15(GDF-15),a member of the transforming growth factorβsuperfamily,is considered a potential therapeutic target for metabolic disorders.This study investigated the impact of magnolol on GDF-15 production and its underlying mechanism.The research examined the pharmacological effect of magnolol on GDF-15 expression in vitro and in vivo,and determined the involvement of endoplasmic reticulum(ER)stress signaling in this process.Luciferase reporter assays,chromatin immunoprecipitation,and in vitro DNA binding assays were employed to examine the regulation of GDF-15 by activating transcription factor 4(ATF4),CCAAT enhancer binding proteinγ(CEBPG),and CCCTC-binding factor(CTCF).The study also investigated the effect of magnolol and ATF4 on the activity of a putative enhancer located in the intron of the GDF-15 gene,as well as the influence of single nucleotide polymorphisms(SNPs)on magnolol and ATF4-induced transcription activity.Results demonstrated that magnolol triggers GDF-15 production in endothelial cells(ECs),hepatoma cell line G2(HepG2)and hepatoma cell line 3B(Hep3B)cell lines,and primary mouse hepatocytes.The cooperative binding of ATF4 and CEBPG upstream of the GDF-15 gene or the E1944285 enhancer located in the intron led to full-power transcription of the GDF-15 gene.SNP alleles were found to impact the magnolol and ATF4-induced transcription activity of GDF-15.In high-fat diet ApoE^(-/-)mice,administration of magnolol induced GDF-15 production and partially suppressed appetite through GDF-15.These findings suggest that magnolol regulates GDF-15 expression through priming of promoter and enhancer activity,indicating its potential as a drug for the treatment of metabolic disorders. 展开更多
关键词 MAGNOLOL Growth/differentiation factor-15 Activating transcription factor 4 CCAAT enhancer binding proteinγ ENHANCER Metabolic disorder
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Fatigue strength optimization of high-strength steels by precisely controlling microstructure and inclusions 被引量:1
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作者 Zikuan Xu peng Wang +6 位作者 peng zhang Bin Wang Yang Liu Yikun Luan Pei Wang Dianzhong Li Zhefeng zhang 《Journal of Materials Science & Technology》 2025年第27期165-176,共12页
With the increasing demand for high-performance metallic materials,the improvement of fatigue strength(FS)has become a crucial issue.This study focuses on the AISI 52100 steel,a material with leading fatigue performan... With the increasing demand for high-performance metallic materials,the improvement of fatigue strength(FS)has become a crucial issue.This study focuses on the AISI 52100 steel,a material with leading fatigue performance and low-cost raw material,aiming to further improve its FS.It is found that the fatigue damage mechanism of 52100 steels with different tensile strengths has undergone significant changes,and the inclusions,mainly nitride and oxide,are key factors limiting the further improvement of FS.Therefore,the size reduction and modification of inclusions were attempted through the rare earth addition and strict control of harmful elements.Combining targeted microstructure adjustment,the FS of the 52100 steel has been further enhanced to~1.6 GPa,exceeding that of other metallic materials(performed in uniaxial tension with a stress ratio of R=0.1),and thus establishing it as a standout for its exceptional performance-to-cost ratio.By clarifying the influences of different types of inclusions on fatigue performance and establishing the correlation between micro-hardness(or strength)and FS,an optimization strategy for FS improvement of the 52100 steel was proposed.The FS has been improved by approximately 187 MPa at most by implementing this strategy.These achievements provide feasible technical approaches and theoretical foundations for the anti-fatigue design of metallic materials. 展开更多
关键词 Bearing steel Fatigue strength INCLUSION Rare earth element Heat treatment
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Cross-section design of the flow channels in membrane electrode assembly electrolyzer for CO_(2) reduction reaction through numerical simulations 被引量:1
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作者 Lili zhang Hui Gao +7 位作者 Gong zhang Yuning Dong Kai Huang Zifan Pang Tuo Wang Chunlei Pei peng zhang Jinlong Gong 《Chinese Chemical Letters》 2025年第1期332-337,共6页
Membrane electrode assembly(MEA)is widely considered to be the most promising type of electrolyzer for the practical application of electrochemical CO_(2) reduction reaction(CO_(2)RR).In MEAs,a square-shaped cross-sec... Membrane electrode assembly(MEA)is widely considered to be the most promising type of electrolyzer for the practical application of electrochemical CO_(2) reduction reaction(CO_(2)RR).In MEAs,a square-shaped cross-section in the flow channel is normally adopted,the configuration optimization of which could potentially enhance the performance of the electrolyzer.This paper describes the numerical simulation study on the impact of the flow-channel cross-section shapes in the MEA electrolyzer for CO_(2)RR.The results show that wide flow channels with low heights are beneficial to the CO_(2)RR by providing a uniform flow field of CO_(2),especially at high current densities.Moreover,the larger the electrolyzer,the more significant the effect is.This study provides a theoretical basis for the design of high-performance MEA electrolyzers for CO_(2)RR. 展开更多
关键词 Electrochemical reduction of CO_(2) Membrane electrode assembly Mass transfer Gas diffusion electrode Computational fluid dynamics
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Comparison of Reflectivity Consistency between Spaceborne Precipitation Radar and Ground-based Weather Radar in China and the United States 被引量:1
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作者 peng CHEN Lin CHEN +3 位作者 Gang WANG Qiong WU Huiying WANG peng zhang 《Advances in Atmospheric Sciences》 2025年第7期1376-1394,共19页
The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflect... The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflectivity observed by GPM Ku PR is compared quantitatively against GR networks from CINRAD of China and NEXRAD of the United States,and the volume matching method is used for spatial matching.Additionally,a novel frequency correction method for all phases as well as precipitation types is used to correct the GPM Ku PR radar frequency to the GR frequency.A total of 20 GRs(including 10 from CINRAD and 10 from NEXRAD)are included in this comparative analysis.The results indicate that,compared with CINRAD matched data,NEXRAD exhibits larger biases in reflectivity when compared with the frequency-corrected Ku PR.The root-mean-square difference for CINRAD is calculated at 2.38 d B,whereas for NEXRAD it is 3.23 d B.The mean bias of CINRAD matched data is-0.16 d B,while the mean bias of NEXRAD is-2.10 d B.The mean standard deviation of bias for CINRAD is 2.15 d B,while for NEXRAD it is 2.29 d B.This study effectively assesses weather radar data in both the United States and China,which is crucial for improving the overall consistency of global precipitation estimates. 展开更多
关键词 GPM DPR volume matching REFLECTIVITY ground-based radar
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Multi-metal synergistic integration for electronic structure regulation in schreibersite-type Mo_(2)Fe_(0.8)Ru_(0.2)P electrocatalysts:Exceptional enhancement of activity and stability for alkaline hydrogen evolution reaction 被引量:1
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作者 peng zhang Shiyu Xu +10 位作者 Hao Li Chenglin Cui Shengyang Huang Zhengyang Li Hyun Jun Song Lirui Mao Chan-Hwa Chung Ho Seok Park Jin Yong Lee Ji Man Kim Pil J.Yoo 《Journal of Energy Chemistry》 2025年第9期665-674,I0018,共11页
Employing multiple metals for synergistic electronic structure regulation emerges as a promising approach to develop highly efficient and robust electrocatalysts for hydrogen evolution at ampere levels.In this study,a... Employing multiple metals for synergistic electronic structure regulation emerges as a promising approach to develop highly efficient and robust electrocatalysts for hydrogen evolution at ampere levels.In this study,a series of Schreibersite-type intermetallic compounds,particularly Mo_(2)Fe_(0.8)Ru_(0.2)P,are synthesized through high-temperature solid-phase synthesis.Experimental results demonstrate that the integration of Ru significantly improves the kinetics of proton adsorption and desorption during the hydrogen evolution reaction(HER).Additionally,density functional theory(DFT)calculations and X-ray absorption near edge structure(XANES)analyses effectively corroborate the pronounced d-orbital hybridization of Fe within the structure,which facilitates the transfer of hydroxide ions and the maintenance of material durability during alkaline HER processes.Remarkably,Mo_(2)Fe_(0.8)Ru_(0.2)P exhibits superior alkaline HER activity,characterized by an overpotential of merely 48 mV at a current density of 10 mA cm^(-2).After prolonged operation of 1000 h at high current densities(1.1 A cm^(-2)),the activity decline remains minimal,under 4%(with overpotential increasing from 258 mV to 268 mV).These results demonstrate the potential of strategically combining metallic elements to design high-performance industrial-grade electrocatalysts. 展开更多
关键词 Hydrogen evolution reaction Multi-metallic regulation Schreibersite ELECTROCATALYSTS STABILITY
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Construction of efficient electrodes for CO_(2)RR through microenvironment regulation of hydrophobic ionomer 被引量:1
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作者 Qingfeng Chang Gong zhang +7 位作者 Jinxing Chen Xiaowei Du Chujun Wang Yuan Cai Yuzhe Du peng zhang Tuo Wang Jinlong Gong 《Journal of Energy Chemistry》 2025年第9期373-380,I0011,共9页
CO_(2)reduction reaction(CO_(2)RR)electrolyzers based on gas diffusion electrode(GDE)enable the direct mass transfer of CO_(2)to the catalyst surface for participation in the reaction,thereby establishing an efficient... CO_(2)reduction reaction(CO_(2)RR)electrolyzers based on gas diffusion electrode(GDE)enable the direct mass transfer of CO_(2)to the catalyst surface for participation in the reaction,thereby establishing an efficient three-phase reaction interface that significantly enhances current density.However,current hydrophobic modification methods face difficulties in achieving precise and substantial control over wettability,and the hydrophobic modifiers tend to significantly impair the conductivity of the electrode and ion transport capabilities.This study employs Nafion ionomers to hydrophobically modify the threedimensional catalyst layer,revealing the bifunctionality of Nafion.The fluorinated backbone of Nafion ensures the hydrophobicity of the entire catalyst layer,while its sulfonic acid groups promote ion transport,without significantly affecting the conductivity of the electrode.Furthermore,by employing modifiers with distinct wettability characteristics,a highly efficient and large-scale manipulation of the hydrophilic/hydrophobic properties of the catalyst layer was successfully realized.The electrode,constructed with silver nanopowder as a representative catalyst and modified with the hydrophobic ionomer Nafion,exhibits a substantial enhancement in both catalytic activity and durability.The optimized electrode exhibited exceptional electrocatalytic performance in both flow cell and membrane electrode assembly(MEA)configurations.Notably,in the MEA,the electrode achieved a remarkable CO Faradaic efficiency(FE)of 93.3%at a total current density of 200 mA cm^(-2),while maintaining stable operation for over 62 h. 展开更多
关键词 GDE CO_(2)RR WETTABILITY Hydrophobic ionomer
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增材制造高熵合金的微观组织及其对力学性能的影响研究
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作者 张晓宇 黄家楷 +7 位作者 慈世伟 阳颖飞 杨俊杰 李杰 任盼 李萍 张鹏 王启伟 《表面工程与再制造》 2025年第1期33-35,36-52,共20页
高熵合金因其优异的耐磨性、耐蚀性、高比强度、高温蠕变性能,广泛应用于医疗、存储系统、运输、航空航天、核能和汽车工业等工程领域。增材制造方法因其多功能性和灵活性而备受关注,且其可以应对新的材料挑战,是一种适合开发新金属材... 高熵合金因其优异的耐磨性、耐蚀性、高比强度、高温蠕变性能,广泛应用于医疗、存储系统、运输、航空航天、核能和汽车工业等工程领域。增材制造方法因其多功能性和灵活性而备受关注,且其可以应对新的材料挑战,是一种适合开发新金属材料的技术。通过优化工艺参数,高熵合金和增材制造的结合使材料具备出色的力学性能、更好的耐磨性和耐蚀性。介绍了有关增材制造高熵合金的缺陷的形成原因及解决方法,随后讨论了微观结构方面、相形成、强化机制和由此产生的力学性能。最后,对增材制造高熵合金未来进行了展望,提出了未来可以努力的方向。 展开更多
关键词 高熵合金 增材制造 微观组织 力学性能
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EMP2 promotes hepatocellular carcinoma proliferation and invasion by activating cellular autophagy 被引量:1
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作者 HAIYING PANG FENGBO WU +5 位作者 YU zhang NAN zhang CHUNTING WANG QIU LI GU HE peng zhang 《Oncology Research》 2025年第2期443-464,共22页
Background:EMP2 is a tumor-associated membrane protein belonging to the GAS-3/PMP22 gene family.EMP2 expression demonstrates significant tissue specificity and heterogeneity in various human tissues and tumor tissues,... Background:EMP2 is a tumor-associated membrane protein belonging to the GAS-3/PMP22 gene family.EMP2 expression demonstrates significant tissue specificity and heterogeneity in various human tissues and tumor tissues,where it may play a role in either promoting or inhibiting tumor growth.This study aimed to investigate the expression level,biological functions,and molecular mechanisms of EMP2 in liver cancer.Methods:we analyzed the mRNA expression levels of EMPs family genes in hepatocellular carcinoma(HCC)tissues and normal liver tissues based on the TCGA database and immunohistochemical analysis of tissue microarrays.Subsequently,we constructed HCC cell lines with either knockdown or overexpression of EMP2 to examine the biological functions and molecular mechanisms of EMP2 in tumorigenesis in vivo and in vitro.Results:Bioinformatic and immunohistochemical analysis of tissue microarrays have confirmed the significant upregulation of EMP2 in HCC tissues.In vitro and in vivo studies have shown that downregulation of EMP2 results in a moderate reduction in the proliferation and invasive capacity of HCC cells.Conversely,overexpression of EMP2 enhances the invasive capacity of HCC cells and induces autophagy.Initial investigations into the molecular mechanisms underlying EMP2-mediated enhancement of HCC cell invasion have revealed the dual regulation of EMP2-induced autophagy and the integrin pathway,which synergistically influence the invasive and metastatic potential of HCC cells.Conclusion:EMP2 holds promise as a diagnostic marker for HCC metastasis and a potential target for targeted therapy. 展开更多
关键词 Epithelial membrane protein 2 Hepatocellular carcinoma AUTOPHAGY Integrin pathway
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Advancements and challenges of acupuncture randomized controlled trials 被引量:1
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作者 Wei Song Seetoh Rachel Qin Rui Lim +3 位作者 Run-bing Xu Ming-xun Sun peng zhang Mi-na Wang 《Journal of Integrative Medicine》 2025年第4期333-343,共11页
Acupuncture is an ancient treatment method used in traditional Chinese medicine and has been popularized worldwide.Over the past decade,there has been an increase in the amount of acupuncture research,mostly comprised... Acupuncture is an ancient treatment method used in traditional Chinese medicine and has been popularized worldwide.Over the past decade,there has been an increase in the amount of acupuncture research,mostly comprised of randomized controlled trials(RCTs)that aimed to answer the question on the efficacy of acupuncture.However,poor methodology and low replicability in these acupuncture RCTs have resulted in uncertainty about the efficacy of acupuncture.In this review,current advancements and challenges in acupuncture RCTs,regarding the methodological aspects of randomization,blinding,sham acupuncture and quality of reporting,were discussed.While there have been advancements in various aspects,current acupuncture RCTs still face pressing issues such as inadequate randomization and blinding,unviable sham acupuncture controls,and poor reporting quality.Given these limitations,this review seeks to identify the methodological problems that are responsible for these problems and to suggest solutions that could help to overcome them so as to improve the quality of future studies evaluating the efficacy of acupuncture. 展开更多
关键词 ACUPUNCTURE Randomized controlled trials METHODOLOGY Chinese medicine
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纳米SiC基光催化剂研究进展 被引量:12
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作者 何科林 沈荣晨 +4 位作者 郝磊 李佑稷 张鹏 江吉周 李鑫 《物理化学学报》 SCIE CAS CSCD 北大核心 2022年第11期21-44,共24页
工业化无疑促进了经济的发展,提高了生活水平,但也导致了一些问题,包括能源危机、环境污染、全球变暖等,其中这些所产生问题主要是由燃烧煤炭、石油和天然气等化石燃料引起的。光催化技术具有利用太阳能将二氧化碳转化为碳氢化合物燃料... 工业化无疑促进了经济的发展,提高了生活水平,但也导致了一些问题,包括能源危机、环境污染、全球变暖等,其中这些所产生问题主要是由燃烧煤炭、石油和天然气等化石燃料引起的。光催化技术具有利用太阳能将二氧化碳转化为碳氢化合物燃料、从水中制氢、降解污染物等优点,从而在解决能源危机的同时避免环境污染,因此被认为是解决这些问题的最有潜力的技术之一。在各种光催化剂中,碳化硅(SiC)由于其优良的电学性能和光电化学性质,在光催化、光电催化、电催化等领域具有广阔的应用前景。本文首先系统地阐述了各种SiC的合成方法,具体包括模板生长法、溶胶凝胶法、有机前驱物热解法、溶剂热合成法、电弧放电法,碳热还原法和静电纺丝等方法。然后详细地总结了提升SiC光催化活性的各种改性策略,如元素掺杂、构建Z型(S型)体系、负载助催化剂、可见光敏化、构建半导体异质结、负载炭材料、构建纳米结构等。最后重点论述了半导体的光催化机理以及SiC复合物在光催化产氢、污染物降解和CO_(2)还原等领域的应用研究进展,并提出了前景展望。 展开更多
关键词 碳化硅 光催化 光催化析氢 光催化降解 光催化CO_(2)还原
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膝关节镜清理联合腓骨近端截骨在膝内侧间室病变骨关节炎治疗中的临床研究 被引量:18
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作者 胡晓晖 李法印 +2 位作者 张鹏 赏后来 郝跃东 《中国现代医学杂志》 CAS 2018年第9期88-93,共6页
目的比较膝关节镜清理联合腓骨近端截骨与单纯膝关节镜清理治疗内侧间室病变膝关节骨性关节炎的临床疗效。方法回顾性分析该院2014年1月-2015年12月收治的部分早中期内侧间室受累为主的膝关节骨性关节炎病例。根据术式分为治疗组(20例)... 目的比较膝关节镜清理联合腓骨近端截骨与单纯膝关节镜清理治疗内侧间室病变膝关节骨性关节炎的临床疗效。方法回顾性分析该院2014年1月-2015年12月收治的部分早中期内侧间室受累为主的膝关节骨性关节炎病例。根据术式分为治疗组(20例):膝关节镜清理联合腓骨近端截骨;对照组(23例):单纯膝关节镜清理。分别于术前、术后2 d、术后12个月记录治疗组、对照组的美国特种外科医院(HSS)评分、视觉模拟评分(VAS)、关节活动度(ROM)及胫股角(FTA)。对其进行组间和组内比较,观察并发症情况。结果两组术前、术后2 d、术后12个月比较采用重复测量设计的方差分析:(1)两组不同时间的HSS膝关节评分、VAS评分、ROM、FTA差异有统计学意义(P<0.05);(2)两组间的HSS膝关节评分、VAS、ROM、FTA差异有统计学意义(P<0.05),治疗组患者在术后的治疗效果更好;(3)两组的HSS膝关节评分、VAS评分、ROM、FTA变化趋势有差异(P<0.05)。结论关节镜清理联合腓骨近端截骨手术相较胫骨高位截骨、膝关节单髁置换及全膝关节置换等手术治疗方式,具备手术费用低、操作过程简单及创伤小等特点,对符合适应证的人群可有效改善临床症状,减轻患者疼痛,值得推广。 展开更多
关键词 关节镜 腓骨 截骨 骨关节炎
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不同脂质层厚度干眼患者泪膜稳定性的观察研究 被引量:11
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作者 张鹏 韩坤岭 +1 位作者 王延铮 王延岭 《国际眼科杂志》 CAS 北大核心 2023年第5期864-866,共3页
目的:探讨不同脂质层厚度条件下泪膜稳定性的差异。方法:纳入2020-06/2021-12于我院就诊的干眼患者194例384眼,应用角膜地形图仪行双眼泪河高度、首次泪膜破裂时间和脂质层厚度测量,分析不同脂质层厚度条件下双眼泪河高度、首次泪膜破... 目的:探讨不同脂质层厚度条件下泪膜稳定性的差异。方法:纳入2020-06/2021-12于我院就诊的干眼患者194例384眼,应用角膜地形图仪行双眼泪河高度、首次泪膜破裂时间和脂质层厚度测量,分析不同脂质层厚度条件下双眼泪河高度、首次泪膜破裂时间的差异及其相关性。结果:根据脂质层厚度将纳入患者(384眼)分为脂质丰富组(49眼)、脂质平衡组(27眼)、脂质轻微缺乏组(266眼)、脂质显著缺乏组(42眼),四组泪河高度有差异(P=0.022),首次泪膜破裂时间无差异(P=0.322)。脂质层厚度分级与泪河高度呈正相关(r_(s)=0.143,P=0.006),与首次泪膜破裂时间无相关性(r_(s)=-0.090,P=0.083);泪河高度与首次泪膜破裂时间也无相关性(r_(s)=0.038,P=0.460)。结论:泪膜脂质层厚度不同的干眼患者泪膜稳定性无明显差异。 展开更多
关键词 泪膜 脂质层 干眼 泪河高度 泪膜破裂时间
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考虑温度效应的斜拉桥塔-索-主梁耦合振动模型及影响分析 被引量:8
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作者 汪峰 彭章 +1 位作者 李浩然 刘章军 《公路交通科技》 CAS CSCD 北大核心 2018年第11期51-60,共10页
温度变化不仅会改变斜拉索的索力、频率以及边界条件,引起振动过程中的分叉现象,还会破坏振动控制的鲁棒性,掩盖结构损伤识别参数以及状态评估。为了研究非均匀温度场中索梁组合结构的非线性振动行为机理。将温度效应作为索和主梁振动... 温度变化不仅会改变斜拉索的索力、频率以及边界条件,引起振动过程中的分叉现象,还会破坏振动控制的鲁棒性,掩盖结构损伤识别参数以及状态评估。为了研究非均匀温度场中索梁组合结构的非线性振动行为机理。将温度效应作为索和主梁振动的边界条件,引入高精度抛物线形,考虑拉索几何非线性、倾角、索的自重弦向分力影响,推导了热力学平衡状态下的索梁组合结构耦合振动微分方程,构建了考虑温度效应的塔-索-主梁连续耦合非线性振动精细化模型。编制程序研究了温度变化对拉索和主梁的固有频率影响,以及索梁温差对桥塔-拉索-主梁连续结构参数振动的影响。结果表明:温度变化对拉索和主梁固有频率影响不同,在塔-索-主梁频率比为2∶1∶1的主共振模式下,温度变化量每增加5℃,拉索固有频率下降0. 17%-0. 2%,主梁固有频率下降4%-7%;索梁温差的拉索振动具有明显"拍"特征,且索和主梁之间存在能量传递,随着正索梁温差逐渐增大,拉索最大振动幅值减小,但振动频率逐渐增大;随着负索梁温差的增大,拉索最大响应振幅增大,振动频率逐渐减小;考虑索梁温差和端部联合激励下的拉索振幅比单一端部激励振幅要小,拍频要大,在2∶1∶1主共振和2∶1∶2的参数共振模式下,拉索振动有明显的"拍"特征,而主梁振动相对平稳。 展开更多
关键词 桥梁工程 耦合振动 数值仿真 索梁组合结构 温度效应
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Brain Functional Network Changes in Patients with Poststroke Cognitive Impairment Following Acupuncture Therapy 被引量:1
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作者 Ran Wang Nian Liu +4 位作者 Hao Xu peng zhang Xiaohua Huang Lin Yang Xiaoming zhang 《Health》 2024年第9期856-871,共16页
Background: The mechanisms by which acupuncture affects poststroke cognitive impairment (PSCI) remain unclear. Objective: To investigate brain functional network (BFN) changes in patients with PSCI after acupuncture t... Background: The mechanisms by which acupuncture affects poststroke cognitive impairment (PSCI) remain unclear. Objective: To investigate brain functional network (BFN) changes in patients with PSCI after acupuncture therapy. Methods: Twenty-two PSCI patients who underwent acupuncture therapy in our hospital were enrolled as research subjects. Another 14 people matched for age, sex, and education level were included in the normal control (HC) group. All the subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans;the PSCI patients underwent one scan before acupuncture therapy and another after. The network metric difference between PSCI patients and HCs was analyzed via the independent-sample t test, whereas the paired-sample t test was employed to analyze the network metric changes in PSCI patients before vs. after treatment. Results: Small-world network attributes were observed in both groups for sparsities between 0.1 and 0.28. Compared with the HC group, the PSCI group presented significantly lower values for the global topological properties (γ, Cp, and Eloc) of the brain;significantly greater values for the nodal attributes of betweenness centrality in the CUN. L and the HES. R, degree centrality in the SFGdor. L, PCG. L, IPL. L, and HES. R, and nodal local efficiency in the ORBsup. R, ORBsupmed. R, DCG. L, SMG. R, and TPOsup. L;and decreased degree centrality in the MFG. R, IFGoperc. R, and SOG. R. After treatment, PSCI patients presented increased degree centrality in the LING.L, LING.R, and IOG. L and nodal local efficiency in PHG. L, IOG. R, FFG. L, and the HES. L, and decreased betweenness centrality in the PCG. L and CUN. L, degree centrality in the ORBsupmed. R, and nodal local efficiency in ANG. R. Conclusion: Cognitive decline in PSCI patients may be related to BFN disorders;acupuncture therapy may modulate the topological properties of the BFNs of PSCI patients. 展开更多
关键词 Cognitive Decline Poststroke Cognitive Impairment Functional Magnetic Resonance Imaging Brain Functional Network Graph Theoretical Analysis
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A Count Sketch Maximal Weighted Residual Kaczmarz Method with Oblique Projection for Highly Overdetermined Linear Systems 被引量:2
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作者 peng zhang Longyan Li Pingping zhang 《Advances in Pure Mathematics》 2022年第4期260-270,共11页
Motivated by the count sketch maximal weighted residual Kaczmarz (CS-MWRK) method presented by Zhang and Li (Appl. Math. Comput., 410, 126486), we combine the count sketch tech with the maximal weighted residual Kaczm... Motivated by the count sketch maximal weighted residual Kaczmarz (CS-MWRK) method presented by Zhang and Li (Appl. Math. Comput., 410, 126486), we combine the count sketch tech with the maximal weighted residual Kaczmarz Method with Oblique Projection (MWRKO) constructed by Wang, Li, Bao and Liu (arXiv: 2106.13606) to develop a new method for solving highly overdetermined linear systems. The convergence rate of the new method is analyzed. Numerical results demonstrate that our method performs better in computing time compared with the CS-MWRK and MWRKO methods. 展开更多
关键词 Count Sketch Oblique Projection Kaczmarz Method Linear System
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