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Chinese Journal of Aeronautics 2024年第3期37卷 34-48页

作者： Fanzhi ZENG tianxin zhang Denggao TANG Jinping LI Chao YAN School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China School of Aeronautical Engineering Air Force Engineering UniversityXi’an 710038China

Accurate prediction of Shock-Wave/Boundary Layer Interaction(SWBLI)flows has been a persistent challenge for linear eddy viscosity models.A major limitation lies in the isotropic representation of the Reynolds stress,as assumed under the Boussinesq *** studies have shown promise in improving the prediction capability for incompressible separation flows by perturbing the Reynolds-stress anisotropy ***,it remains uncertain whether this approach is effective for SWBLI flows,which involve compressibility and *** address this issue,this study systematically quantifies the structural uncertainty of the anisotropy for oblique SWBLI *** eigenspace perturbation method is applied to perturb the anisotropy tensor predicted by the Menter Shear–Stress Transport(SST)model and reveal the impacts of anisotropy on the prediction of quantities of interest,such as separation and reattachment positions,wall static pressure,skin friction,and heat *** results demonstrate the potential and reveal the challenges of eigenspace perturbation in improving the SST ***,a detailed analysis of turbulent characteristics is performed to identify the source of *** findings indicate that eigenspace perturbation primarily affects turbulent shear stress,while the prediction error of the SST model is more related to turbulent kinetic energy.

关键词： Shock-wave/boundary layer interaction(SWBLI) Turbulence models Uncertainty analysis Eigenspace perturbation Anisotropy

基于介质碳化通道电阻与温度映射关系的光伏直流汇集系统早期故障判别

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电网技术 2024年第4期48卷 1645-1653,I0075,I0077,I0078页

作者：张旸贾科张恬昕施志明毕天姝新能源电力系统国家重点实验室(华北电力大学) 北京市昌平区102206 新能源与储能运行控制国家重点实验室(中国电力科学研究院有限公司) 北京市海淀区100192

光伏中压直流汇集系统中,极间短路故障过流很可能迫使换流器在几毫秒内闭锁,保护来不及动作,引发整个系统停运。该问题可通过提前识别并隔离直流线路中的早期故障来解决。然而在直流线路上,早期故障与绝缘缺陷尚缺乏明确的边界,故障检... 详细信息

光伏中压直流汇集系统中,极间短路故障过流很可能迫使换流器在几毫秒内闭锁,保护来不及动作,引发整个系统停运。该问题可通过提前识别并隔离直流线路中的早期故障来解决。然而在直流线路上,早期故障与绝缘缺陷尚缺乏明确的边界,故障检测判据的阈值难以给定。为此,该文提出了基于碳化通道电阻与温度映射关系的早期故障边界给定原则。基于早期故障发展机理,建立了电缆早期故障实验拟合模型,选取介质碳化通道电阻为故障特征量。在计及系统电压控制约束条件下,解析电缆层间温差与碳化通道电阻的映射关系,进而确定早期故障边界。在此基础上提出了基于故障介质碳化通道电阻值的早期故障判据。仿真结果证明了早期故障边界的合理性以及早期故障判据的有效性,能够为光伏中压直流汇集系统的持续安全运行提供保障。

关键词：直流汇集系统早期故障故障边界故障判别

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深空探测科学目标谱系构建方案探索

深空探测学报（中英文） 2024年第1期11卷 79-89页

作者：刘继忠葛平康焱张天馨姜亦宸马克邵艳利探月与航天工程中心北京100041 深空探测实验室北京100195

中国深空探测活动正在由技术驱动和科学牵引并举逐步发展到以科学引领为主、牵引技术进步的阶段。面向中国深空探测高质量发展需求,创新性提出科学目标谱系概念与方案设想。以科学目标为核心,汇聚深空探测工程、科学、技术、应用大数据... 详细信息

中国深空探测活动正在由技术驱动和科学牵引并举逐步发展到以科学引领为主、牵引技术进步的阶段。面向中国深空探测高质量发展需求,创新性提出科学目标谱系概念与方案设想。以科学目标为核心,汇聚深空探测工程、科学、技术、应用大数据,利用人工智能、云计算等技术,将相关要素进行有机组织、信息关联和知识挖掘,建立深空领域“关联成谱,脉络为系”的大模型,打造大知识智能平台。借助该平台,能够充分利用历史数据、立足当前能力,对深空探测未来的规划发展提供生成式的知识与信息支持,推动数据驱动的深空研究范式变革。

关键词：科学目标谱系科学牵引深空大模型数据驱动

A three-equation transition model with mechanical considerations

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Chinese Journal of Aeronautics 2022年第11期35卷 178-190页

作者： tianxin zhang Jianqiang CHEN Yatian ZHAO Zaijie LIU Chao YAN School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Computational Aerodynamics Institute China Aerodynamics Research&Development CenterMianyang 621000China School of Aeronautics and Astronautics Central South UniversityChangsha 410083China

A three-equation transition model based on the transition V-model is proposed for subsonic flows in this study. Considering the mechanical approximation of the generation process of the pre-transitional vorticities, the value of laminar Reynolds shear stress related to the mean shear deformation was calculated in the original transition V-model. Then a new transition model, named V-SA model, was proposed, which considered the phenomenological process of transition and presented great results for flows with and without pressure gradient. It is well-known that the baseline Shear Stress Transport(SST) turbulence model shows excellent performance of accuracy and robustness in plentiful flow cases, but it is important to predict boundary layer transition. The current model(V-SST) successfully couples the V-model to the SST turbulence model by introducing the effective turbulent viscosity and additional correction terms into the transport equations. A thorough evaluation of its ability to predict transition features is performed versus the well-documented flat plate of ERCOFTAC, including T3A and T3B without pressure gradient, T3L2 and T3L3 with semi-circular leading edge, the three-dimensional 6:1 prolate-spheroid under two angles of attack, and the NLR-7301 airfoil under different Mach numbers. Numerical results show that the current model has an attractive and superior performance in the simulation of boundary layer transition processes.

关键词： Laminar kinetic energy Mechanical consideration Shear stress transport turbulence model Transition model V-model

Lithospheric structures across the Qiman Tagh and western Qaidam Basin revealed by magnetotelluric data collected using a self-developed SEP system

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Science China Earth Sciences 2021年第10期64卷 1813-1820页

作者： Qingyun DI Guoqiang XUE Zhongxing WANG Lanfang HE Renzhong PEI tianxin zhang Guangyou FANG CAS Engineering Laboratory for Deep Resources Equipment and Technology Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Institutions of Earth Science Chinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Aerospace Informatory Research Institute Chinese Academy of SciencesBeijing 100094China

Geophysics offers an important means to investigate the physical processes occurring inside the *** particular,since the 1960s,electromagnetic(EM)methods have played important roles in mineral exploration and engineering *** investigation requires extensive data acquisition and experimental analysis based on geophysical ***,high-performance geophysical equipment,particularly EM exploration equipment,has been dominated by large geophysical companies from the United States,Canada,Germany,and other European countries for *** has limited the development of deep exploration technology in ***,we have developed a high-resolution acquisition system with a wireless control unit and a high-power transmitting system for surface EM prospecting(SEP).The new system has been tested in the high-intensity,noisy environment in Jian-sanjiang area,Heilongjiang *** then conducted a field survey on the western edge of Qaidam Basin,Qinghai Province.A highly conductive anomaly was found in the upper mantle below the Qinmantage Mountains,which indicates a possible northward fluid channel that runs from below the Qinmantage Mountains to the bottom of the western crust of the Qaidam *** of this significant feature was made possible by the new SEP for its better resolution than the previous ***,geophysical analysis confirmed that the thick Cenozoic sediments of the Qaidam Basin are underlain by rigid Precambrian basement rocks and are characterized by a series of *** resistivity profile indicates that the Qaidam Basin was formed due to the folding structures in the northern part of the Qinghai-Tibet Plateau which provided an additional evidence for the uplifting of the Qinghai-Tibet Plateau.

关键词： Surface electromagnetic prospecting system(SEP) Self developed system High resolution Western Qaidam Basin Lithospheric structures

月球南极区域不同高度光照条件计算方法及其在着陆点选址中的应用

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航天器环境工程 2024年第4期41卷 397-403页

作者：苏秀中葛平张天馨康焱周艾玉李云飞胡震宇上海宇航系统工程研究所上海201109 探月与航天工程中心北京100190 深空探测实验室北京100195

针对目前月球南北极探测中多数月面光照条件计算方法得出的结果误差大,难以在航天任务规划和科学研究中应用的问题,提出考虑高精地形的月球南北极光照条件实时计算方法:基于目前已有的最高精度地形数据,通过逐方位角搜索地平线并计算仰... 详细信息

针对目前月球南北极探测中多数月面光照条件计算方法得出的结果误差大,难以在航天任务规划和科学研究中应用的问题,提出考虑高精地形的月球南北极光照条件实时计算方法:基于目前已有的最高精度地形数据,通过逐方位角搜索地平线并计算仰角,再结合太阳高度角和太阳圆盘视直径,得到该地点光照条件的计算结果。该方法的光照条件计算结果准确,同时可自定义地形搜索范围和精度,进一步可输出任意时间跨度的当地光照情况。基于该方法选取月球南极若干点作为预选着陆点,计算各着陆点在离地高度分别为2、5、8、10、15 m处的全年平均光照率,并分析离地高度对光照条件的影响规律,为后续任务设计提供参考。

关键词：月球南极数字高程模型光照条件着陆点选址

Effects of Nitrogen Doping on Microstructures and Irradiation Resistance of Ti-Zr-Nb-V-Mo Refractory High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1007-1018页

作者： Huanzhi zhang tianxin Li Qianqian Wang Zhenbo Zhu Hefei Huang Yiping Lu Engineering Research Center of High Entropy Alloy Materials(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Shanghai Institute of Applied Physics Chinese Academy of Sciences(CAS)Shanghai201800China

Interstitial strengthening with nitrogen(N)is one of the effective ways to improve the mechanical properties of HEAs,but the effects of N on the microstructures and mechanical properties of the irradiated HEAs have not been studied ***,the microstructures and mechanical properties of N-free and N-doped Ti_(2)ZrNbV_(0.5)Mo_(0.2)HEAs before and after He irradiation were *** results showed that the solid solution strengthening caused by interstitial N improved the yield strength at room temperature and 1023 K without significantly reducing plasticity.N doping significantly promoted the growth,aggregation and wider spatial distribution of He bubbles by enhancing the mobility of He atoms/He-vacancy complexes,with the average size of He bubbles increasing from 10.4 nm in N-free HEA to 31.0 nm in N-doped *** addition,N-doped HEA showed a much higher irradiation hardness increment and hardening fraction than N-free *** to conventional materials doped with N,the introduction of N into Ti_(2)ZrNbV_(0.5)Mo_(0.2)HEA had adverse effects on its resistance to He bubble growth and irradiation *** results of this study indicated that N doping may not improve the irradiation resistance of HEAs.

关键词： High-entropy alloys Nitrogen doping Mechanical properties Helium bubbles Irradiation resistance

TB9钛合金棒线材制备过程中微观组织和力学性能演变

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材料开发与应用 2024年第4期39卷 59-65,122页

作者：董恩涛滕艾均耿乃涛方强康强郭杰张天馨鞍钢集团北京研究院有限公司北京102211 成都先进金属材料产业技术研究院股份有限公司四川成都610300

通过光学显微镜、扫描电镜、电子背散射衍射技术等系统研究了TB9钛合金棒线材在制备过程中的微观组织及力学性能的演变过程。结果表明:通过真空自耗电弧熔炼、锻造、轧制及拉拔等工艺能够制备出表面质量良好、横截面组织性能一致的不同... 详细信息

通过光学显微镜、扫描电镜、电子背散射衍射技术等系统研究了TB9钛合金棒线材在制备过程中的微观组织及力学性能的演变过程。结果表明:通过真空自耗电弧熔炼、锻造、轧制及拉拔等工艺能够制备出表面质量良好、横截面组织性能一致的不同规格TB9钛合金棒线材产品。其中,开坯锻态组织由随机取向的粗大β相及极少量动态再结晶(DRX)晶粒构成,平均晶粒尺寸在1000μm以上。径锻态组织主要由约400μm的β晶粒构成,累计应变的增加使得DRX晶粒百分数增加。多道次热变形获得的?10 mm棒材盘圆组织由尺寸为15μm的细小晶粒组成,具有显著的热加工变形特征,固溶水冷处理能使组织均匀并获得无畸变β晶粒。热拉拔变形能够进一步细化晶粒,并提高TB9钛合金强度,强度最高可达1100 MPa以上,但塑性有所下降。

关键词： TB9钛合金棒线材微观组织力学性能再结晶

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Naringin ameliorates H_(2)O_(2)-induced oxidative damage in cells and prolongs the lifespan of female Drosophila melanogaster via the insulin signaling pathway

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Food Science and Human Wellness 2024年第3期13卷 1231-1245页

作者： Xiaomei Du Kexin Wang Xiaoyan Sang Xiangxing Meng Jiao Xie tianxin Wang Xiaozhi Liu Qun Huang Nan zhang Hao Wang State Key Laboratory of Food Nutrition and Safety Tianjin University of Science and TechnologyTianjin 300457China The key Laboratory of Environmental Pollution Monitoring and Disease Control Ministry of EducationGuizhou Medical UniversityGuizhou 550025China Department of neurosurgery the Fifth Central Hospital of TianjinTianjin 300450China Tianjin Key Laboratory of Epigenetics for Organ Department in Preterm Infants the Fifth Central Hospital of TianjinTianjin 300450China

Naringin exists in a wide range of Chinese herbal medicine and has proven to possess several pharmacological *** this study,PC12,HepG2 cells,and female Drosophila melanogaster were used to investigate the antioxidative and anti-aging effects of naringin and explore the underlying *** results showed that naringin inhibited H_(2)O_(2)-induced decline in cell viability and decreased,the content of reactive oxygen species in ***,naringin prolonged the lifespan of flies,enhanced the abilities of climbing and the resistance to stress,improved the activities of antioxidant enzymes,and decreased malondialdehyde *** also improved intestinal barrier dysfunction and reduced abnormal proliferation of intestinal stem ***,naringin down-regulated the mRNA expressions of inr,chico,pi 3k,and akt-1,and up-regulated the mRNA expressions of dilp2,dilp3,dilp5,and foxo,thereby activating autophagy-related genes and increasing the number of ***,the mutant stocks assays and computer molecular simulation results further indicated that naringin delayed aging by inhibiting the insulin signaling(IIS)pathway and activating the autophagy pathway,which was consistent with the result of network pharmacological predictions.

关键词： Drosophila melanogaster Insulin signaling(IIS)pathway Naringin PC12 cell HepG2 cell

DNA/RNA helicase DHX36 is required for late stages of spermatogenesis

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Journal of Molecular Cell Biology 2022年第11期14卷 50-61页

作者： Kejia zhang tianxin zhang Yujie zhang Jinyu Yuan Xinzhe Tang Chaobao zhang Qianqian Yin Yonglian zhang Ming-Han Tong School of Life Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesChinese Academy of SciencesHangzhou 310024China State Key Laboratory of Molecular Biology Shanghai Key Laboratory of Molecular AndrologyShanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200031China

Spermatogenesis is a highly complex developmental process that typically consists of mitosis, meiosis, and spermiogenesis. DNA/RNA helicase DHX36, a unique guanine-quadruplex (G4) resolvase, plays crucial roles in a variety of biological processes. We previously showed that DHX36 is highly expressed in male germ cells with the highest level in zygotene spermatocytes. Here, we deleted Dhx36 in advanced germ cells with Stra8-GFPCre and found that a Dhx36 deficiency in the differentiated spermatogonia leads to meiotic defects and abnormal spermiogenesis. These defects in late stages of spermatogenesis arise from dysregulated transcription of G4-harboring genes, which are required for meiosis. Thus, this study reveals that Dhx36 plays crucial roles in late stages of spermatogenesis.

关键词： Dhx36 meiosis guanine-quadruplex(G4) Spo11 synapsis meiotic recombination crossover