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Analytical model of cutting force in axial ultrasonic vibration-assisted milling in-situ TiB_(2)/7050Al PRMMCs

Chinese Journal of Aeronautics 2021年第4期34卷 160-173页

作者： xiaofen liu Wenhu WANG Ruisong JIANG Yifeng XIONG Kunyang LIN Junchen LI Chenwei SHAN Key Laboratory of High Performance Manufacturing for Aero Engine Ministry of Industry and Information TechnologySchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi'an 710072China Engineering Research Center of Advanced Manufacturing Technology for Aero Engine Ministry of EducationSchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi'an 710072China School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China

Ultrasonic vibration-assisted milling has been widely applied in machining the difficultto-cut materials owing to the remarkable improvements in reducing the cutting ***,analytical models to reveal the mechanism and predict the cutting force of ultrasonic vibrationassisted milling metal matrix composites are still needed to be *** this paper,an analytical model of cutting force was established for ultrasonic vibration-assisted milling in-situ TiB_(2)/7050 Al metal matrix *** modeling,change of motion of the cutting tool,contact of toolchip-workpiece and acceleration of the chip caused by ultrasonic vibration was considered based on equivalent oblique cutting ***,material properties,tool geometry,cutting parameters and vibration parameters were taken into ***,the developed analytical force model was validated with and without ultrasonic vibration milling experiments on in-situ TiB_(2)/7050 Al metal matrix *** predicted cutting forces show to be consistent well with the measured cutting ***,the relative error of instantaneous maximum forces between the predicted and measured data is from 0.4%to 15.1%.The analytical model is significant for cutting force prediction not only in ultrasonic-vibration assisted milling but also in conventional milling in-situ TiB_(2)/7050 Al metal matrix composites,which was proved with general applicability.

关键词： Al-MMCs Analytical model Cutting force In-situ Milling TiB_(2)particles Ultrasonic vibration

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Investigation on surface roughness,residual stress and fatigue property of milling in-situ TiB_2/7050Al metal matrix composites

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Chinese Journal of Aeronautics 2021年第4期34卷 451-464页

作者： Yifeng XIONG Wenhu WANG Yaoyao SHI Ruisong JIANG Chenwei SHAN xiaofen liu Kunyang LIN Key Laboratory of High Performance Manufacturing for Aero Engine Ministry of Industry and Information TechnologySchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi'an 710072China Engineering Research Center of Advanced Manufacturing Technology for Aero Engine Ministry of EducationSchool of Mechanical EngineeringNorthwestern Polytechnical UniversityXi'an 710072China School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China

For higher efficiency and precision manufacturing,more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue *** present,the in-situ TiB_2/7050 Al metal matrix composites are widely researched due to its attractive properties such as low density,good wear resistance and improved *** is of great significance to investigate the machined surface roughness,residual stress and fatigue life for higher efficiency and precision manufacturing of this new kind *** this study,the surface roughness including two-dimensional and three-dimensional roughness,residual stress and fatigue life of milling in-situ TiB_2/7050 Al metal matrix composites were *** was found from comparative investigation that the three-dimensional surface roughness would be more appropriate to represent the machined surface profile of milling particle reinforced metal matrix *** cutting temperature played a great role on the residual ***,the effect of increasing cutting force could slow down the transformation from compressive stress to tensile stress under 270°*** exponential relationship between three-dimensional roughness and fatigue life was established and the main fracture mechanism was brittle fracture with observation of obvious shellfish veins,river pattern veins and wave shaped veins in fracture surface.

关键词： Fatigue life Metal matrix composite Residual stress Three-dimensional surface roughness TiB_2 particle Two-dimensional surface roughness

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Analysis of stability and robust stability for stochastic hybrid systems with impulsive effects

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Frontiers of Electrical and Electronic Engineering in China 2009年第1期4卷 66-71页

作者： Ying YANG Junmin LI xiaofen liu Department of Applied Mathematics Xidian UniversityXi’an 710071China School of Mathematics and Statistics Zhejiang University of Finance and EconomyHangzhou 310018China

In this article,the problems of stability and robust stability analysis are investigated for a class of Markovian switching stochastic systems,which has impulses at switching *** switching parameters considered form a continuous-time discrete-state homogeneous Markov *** Lyapunov techniques are used to derive sufficient conditions for stability in probability of the overall *** conditions are in linear matrix inequalities form,and can be used to solve stabilization synthesis *** results are extended to the design of a robust-stabilized state-feedback controller as well.A numerical example shows the effectiveness of the proposed approach.

关键词： impulsive system Markovian switching stable in probability linear matrix inequality(LMI) robust stability

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The structure of WbnH in a near active state

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Protein & Cell 2015年第8期6卷 615-618页

作者： Fengzhi Li Siwei Li xiaofen liu Xue Yang Peng Wang Yuequan Shen State Key Laboratory of Medicinal Chemical Biology Nankai University Tianjin 300071 China College of Life Sciences Nankai University Tianjin 300071 China Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 China Synergetic Innovation Center of Chemical Science and Engineer- ing Tianjin 300071 China

Dear Editor, Gram-negative bacteria possess a complicated membrane system that plays an essential role in interactions between bacteria and the envJronment （Reeves and Wang, 2002）. The inner leaflet of the membrane is composed of various glycerophospholipids, and the outer leaflet consists primarily of lipopolysaccharide （LPS） molecules.

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Particle modulations to turbulence in two-phase round jets

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Acta Mechanica Sinica 2009年第5期25卷 611-617页

作者： Bing Wang Huiqiang Zhang Yi liu xiaofen Yan Xilin Wang School of Aerospace, Tsinghua University, 100084 Beijing, China School of Aerospace Tsinghua University 100084 Beijing China

The particle modulations to turbulence in round jets were experimentally studied by means of two-phase velocity measurements with Phase Doppler Anemometer （PDA）. Laden with very large particles, no significant attenuations of turbulence intensities were measured in the farfields, due to small two-phase slip velocities and particle Reynolds number. The gas-phase turbulence is enhanced by particles in the near-fields, but it is significantly attenuated by the small particles in the far-fields. The smaller particles have a more profound effect on the attenuation of turbulence intensities. The enhancements or attenuations of turbulence intensities in the far-fields depends on the energy production, transport and dissipation mechanisms between the two phases, which are determined by the particle prop- erties and two-phase velocity slips. The non-dimensional parameter CTI is introduced to represent the change of turbulence intensity.

关键词： Particle modulations Turbulence intensity Particle sizes Two-phase slip velocity Particle-laden round turbulent jet

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Mechanism regulating the inhibition of lung cancer A549 cell proliferation and structural analysis of the polysaccharide Lycium barbarum

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Food Bioscience 2022年第3期47卷 679-687页

作者： Wenjin Ma Yanbing Zhou Wenjin Lou Bo Wang Bing Li xiaofen liu Jiajun Yang Bo Yang Jianfei liu Duolong Di CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China The Institute of Gansu Province Light Industrial Scientific Research Lanzhou730000China Gansu Provincial Academic Industrial for Medical Research Lanzhou730000China School of Life Science and Engineering Lanzhou University of TechnologyGansu ProvinceLanzhou730050China

The water-soluble polysaccharide LBP-1 was isolated and characterized from Lycium barbarum ***-1 was mainly composed of arabinose,galactose,glucose,xylose,mannose at a molar ratio of 37.53:28.08:14.72:7.83:4.50,*** on nuclear magnetic resonance(NMR)and methylation analysis,the backbone of LBP-1 was speculated in theα-L-Ara(1→[5-α-L-Ara(1→3)-β-D-Galp-(1→]n→4)-α-D-Galp-(1[→5-α-L-Ara(1]n[→6)-β-D-Galp-(1→4)-β-D-Galp-(1→]n,and the side chains of LBP-1 were in theα-L-Ara(1→3)-β-D-Galp-(1→6 *** results showed that LBP-1 inhibited the growth of cancer A549 cells through cell cycle arrest and apoptosis,with an IC50 value of 42.5μg/*** addition,LBP-1 altered the expression of Cyclin D1,Cyclin D3,and CDK 2,thus blocking the cell cycle in G0/G1 phase,reducing cell migration,and regulating the PI3K/Akt/mTOR signaling pathway to induce apoptosis.

关键词： Lycium barbarum polysaccharide Lung cancer cell Apoptosis Cell cycle Structural analysis

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Permissive role of CTCF–Hoxb7a–Cdkn2a/b axis in the emergence of hematopoietic stem and progenitor cells during zebrafish embryogenesis

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Journal of Genetics and Genomics 2024年第9期51卷 974-977页

作者： Wenjuan Zhang xiaofen liu Wenzhi Xue Lei Gao Dantong Li Changbin Jing Jian Zhao Weijun Pan State Key Laboratory of Bioreactor Engineering East China University of Science and TechnologyShanghai 200237China CAS Key Laboratory of Nutrition Metabolism and Food SafetyShanghai Institute of Nutrition and Health(SINH)University of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200031China

Hematopoietic stem and progenitor cells(HsPCs)are a subset population of multi-potent cells with self-renewal capability and differentiation into all lineages of blood cells(Zhang and liu,2024).HSPCs arise from the ventral wall of embryonic dorsal aorta,the hemogenic endothelium in the aorta-gonad-mesonephros(AGM)region,tightly controlled by epigenetic,transcriptional,and signaling networks(Wu and Hirschi,2021).However,how developmental hemogenic endothelium performs cell fate surveillances during HSPC emergence and efficiently eliminates them to avoid abnormal hematopoiesisremainselusive.

关键词： CTCF eliminate hematopoietic

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Ethylene†and fruit softening

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Food Quality and Safety 2017年第4期1卷 253-267页

作者： Greg Tucker Xueren Yin Aidi Zhang MiaoMiao Wang Qinggang Zhu xiaofen liu Xiulan Xie Kunsong Chen Don Grierson Division of Nutritional Biochemistry School of BiosciencesUniversity of NottinghamSutton Bonington CampusLoughboroughLE125RDUK Laboratory of Fruit Quality Biology/The State Agriculture Ministry Laboratory of Horticultural Plant Growth Development and Quality ImprovementZhejiang UniversityHangzhou 310058China Plant&Crop Sciences Division School of BiosciencesUniversity of NottinghamSutton Bonington CampusLoughboroughLE125RDUK

This review is concerned with the mechanisms controlling fruit *** genetic regulators switch on the ripening programme and the regulatory pathway branches downstream,with separate controls for distinct quality attributes such as colour,flavour,texture,and *** plays a critical role as a ripening hormone and is implicated in controlling different facets of ripening,including texture change,acting through a range of transcriptional regulators,and this signalling can be blocked using 1-methylcyclopropene.A battery of at least seven cell-wall-modifying enzymes,most of which are synthesized de novo during ripening,cause major alterations in the structure and composition of the cell wall components and contribute to the softening *** differences between fruits may be related to the precise structure and composition of their cell walls and the enzymes recruited to the ripening programme during *** to slow texture change and reduce fruit spoilage by delaying the entire ripening process can often affect negatively other aspects of quality,and low temperatures,in particular,can have deleterious effects on texture *** silencing has been used to probe the function of individual genes involved in different aspects of ripening,including colour,flavour,ethylene synthesis,and particularly texture *** picture that emerges is that softening is a multi-genic trait,with some genes making a more important contribution than *** future,it may be possible to control texture genetically to produce fruits more suitable for our needs.

关键词： Cell walls Ethene Pectate lyase Polygalacturonase Tomato.

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Inducible expression of endomorphins in murine dendritic cells

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Neural Regeneration Research 2012年第35期7卷 2811-2817页

作者： Xiaohuai Yang Hui Xia Yong Chen xiaofen liu Cheng Zhou Qin Gao Zhenghong Li Department of Urinary Surgery First Hospital of Bengbu Medical College Anhui Key Laboratory of Infection & Immunity Bengbu Medical College Department of Physiology Bengbu Medical College

Bone marrow precursor cells were extracted from C57BL/6J mice aged 7-8 weeks, and dendritic cells were purified using anti-CD1 lc （a specific marker for dendritic cells） antibody-coated magnetic beads. Immunofluorescence staining revealed that the expression levels of endomorphin-1 and endomorphin-2 were upregulated in dendritic cells activated by lipopolysaccharide. An enzyme Jmmunoassay showed that lipopolysaccharide and other Toll-like receptor ligands promoted the secretion of endomorphin-1 and endomorphin-2 from activated dendritic cells. [3H]-thymidine incorporation demonstrated that endomorphin-1 and endomorphin-2 both inhibited the proliferation of T lymphocyte induced by activated dendritic cells. Furthermore, this immunosuppressive effect was blocked by CTOP, a specific antagonist of IJ-opioid receptors. Our experimental findings indicate that activated dendritic cells can induce the expression and secretion of endomorphins, and that endomorphins suppress T lymphocyte proliferation through activation of iJ-opioid receptors.

关键词： dendritic cells endomorphin I J-receptor antigen-presenting cell nerve immunization neuralregeneration

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Improving the Security of N-user Quantum Key distribution with N Quantum Channels

Improving the Security of N-user Quantum Key distribution wi...

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2012年计算机应用与系统建模国际会议

作者： liu xiaofen Chen Licong Pan Rijing School of Mathematics and Computer Science Key Lab of Network Security and Cryptography Fujian Normal University

In a recent paper [C.H. Hong et al., Opt. Commun. 283 (2010) 2644], a n-user quantum key distribution protocol with n quantum channels was presented. By analyzing its security, it is shown that this protocol is insecure for Trent, a dishonest third party, who can steal the key without being detected by a special attack strategy. We give a description of this strategy and then put forward an improved protocol, which can stand against this attack. Furthermore, the improved protocol is feasible in the current technology conditions, because it is just required an incomplete Bell-state measurement in implementation of it.

关键词： Quantum key distribution Entanglement swapping Einstein-Podolsky-Rosen pairs

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