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An axisymmetric characteristic model for enhancing prediction of centrifugal compressor characteristics

chinese Journal of Aeronautics 2024年第4期37卷 203-215页

作者： Peng REN Xiangjun FANG Zeyu JIAO ying HAN School of Energy and Power Engineering Beihang UniversityBeijing 100191China Guangdong Key Laboratory of Modern control Technology Institute of Intelligent ManufacturingGuangdong Academy of SciencesGuangzhou 510070China

Rapid and accurate determination of compressor characteristic maps is essential for the initial design of centrifugal compressors in aircraft power systems. The accuracy of existing methodologies, which rely on combinations of loss models, varies significantly depending on the compressor's geometry and operational range. This variance necessitates substantial experimental or computational Fluid Dynamics(cFD) data for coefficient calibration. To address this challenge, this study presents an axisymmetric characteristic model for compressor performance assessment. This model incorporates the factors of blade angle, meridional passage area, and the radial deflection angle of meridional streamlines of the compressor. These factors are derived from fundamental aerodynamic equations encompassing mass, momentum, and energy conservation of the compressor. In contrast to conventional one-dimensional approaches, the proposed method reduces the number of loss coefficients and more effectively accounts for the impact of geometric alterations on centrifugal compressor properties. Furthermore, the model reduces dependence on experimental and cFD data. Efficacy of the model is validated using experimental data from four distinct types of centrifugal compressors. correlation analysis reveals that the model's coefficients can be expressed as functions of the ratio of the Reynolds number to the impeller tip speed. This ratio serves as a characteristic parameter for the design and optimization of centrifugal compressors. consequently, the proposed method offers an efficient and accurate means for the quick computation of centrifugal compressor characteristics. This is of great significance for improving the efficiency of centrifugal compressors and reducing energy consumption.

关键词： centrifugal compressor Positive problem characteristic prediction Aerodynamic characteristic Axisymmetric model

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Structural Engineering of Hierarchical Magnetic/carbon Nanocomposites via In Situ Growth for High-Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2024年第9期16卷 262-278页

作者： Xianyuan Liu Jinman Zhou ying Xue Xianyong Lu Key Laboratory of Bio‑Inspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191People’s Republic of China

Materials exhibiting high-performance electromagnetic wave absorption have garnered considerable scientific and technological attention,yet encounter significant *** new materials and innovative structural design concepts is crucial for expanding the application field of electromagnetic wave ***,hierarchical structure engineering has emerged as a promising approach to enhance the physical and chemical properties of materials,providing immense potential for creating versatile electromagnetic wave absorption ***,an exceptional multi-dimensional hierarchical structure was meticulously devised,unleashing the full microwave attenuation capabilities through in situ growth,selfreduction,and multi-heterogeneous interface *** hierarchical structure features a three-dimensional carbon framework,where magnetic nanoparticles grow in situ on the carbon skeleton,creating a necklace-like ***,magnetic nanosheets assemble within this *** impedance matching was achieved by precisely adjusting component proportions,and intelligent integration of diverse interfaces bolstered dielectric *** obtain Fe_(3)O_(4)-Fe nanoparticles/carbon nanofibers/Al-Fe_(3)O_(4)-Fe nanosheets composites demonstrated outstanding performance with a minimum reflection loss(RLmin)value of−59.3 dB and an effective absorption bandwidth(RL≤−10 dB)extending up to 5.6 GHz at 2.2 *** notable accomplishments offer fresh insights into the precision design of high-efficient electromagnetic wave absorption materials.

关键词： Electromagnetic wave absorption Hierarchical structure In situ growth Self-reduction

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constructions of optimal binary locally repairable codes via intersection subspaces

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Science china(Information Sciences) 2024年第6期67卷 418-432页

作者： Wenqin ZHANG Deng TANG chenhao ying Yuan LUO School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Locally repairable codes（LRcs）, which can recover any symbol of a codeword by reading only a small number of other symbols, have been widely used in real-world distributed storage systems, such as Microsoft Azure Storage and ceph Storage cluster. Since binary linear LRcs can significantly reduce coding and decoding complexity, constructions of binary LRcs are of particular interest. The aim of this paper is to construct dimensional optimal binary LRcs with disjoint local repair groups. We introduce a method to connect intersection subspaces with binary LRcs and construct dimensional optimal binary linear LRcs with locality 2b（b 3） and minimum distance d 6 by employing intersection subspaces deduced from the direct sum. This method will sufficiently increase the number of possible repair groups of dimensional optimal LRcs, thus efficiently expanding the range of the construction parameters while keeping the largest code rates compared with all known binary linear LRcs with minimum distance d 6 and locality 2b.

关键词： locally repairable codes disjoint local repair groups distributed storage systems intersection subspaces direct sum

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Microstructure evolution and strengthening mechanism of high -performance powder metallurgy TA15 titanium alloy by hot rolling

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1426-1436页

作者： ying Gao ce Zhang Jiazhen Zhang Xin Lu Beijing Advanced Innovation center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsInstitute for Advanced Ma-terials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Engineering Research center for Advanced Rolling Technology National Engineering Research Center for Flat Rolling EquipmentInstitute of Engin-eering TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Hot deformation of sintered billets by powder metallurgy(PM)is an effective preparation technique for titanium alloys,which is more significant for high-alloying *** this study,Ti–6.5Al–2Zr–Mo–V(TA15)titanium alloy plates were prepared by cold press-ing sintering combined with high-temperature hot *** microstructure and mechanical properties under different process paramet-ers were *** microscope,electron backscatter diffraction,and others were applied to characterize the microstructure evolution and mechanical properties strengthening *** results showed that the chemical compositions were uniformly dif-fused without segregation during sintering,and the closing of the matrix craters was accelerated by increasing the sintering *** block was hot rolled at 1200℃ with an 80%reduction under only two passes without *** strength and elongation of the plate at 20–25℃ after solution and aging were 1247 MPa and 14.0%,respectively,which were increased by 24.5%and 40.0%,respect-ively,compared with the as-sintered alloy at 1300℃.The microstructure was significantly refined by continuous dynamic recrystalliza-tion,which was completed by the rotation and dislocation absorption of the substructure surrounded by low-angle grain *** hot rolling combined with heat treatment,the strength and plasticity of PM-TA15 were significantly improved,which resulted from the dense,uniform,and fine recrystallization structure and the synergistic effect of multiple slip systems.

关键词： elemental powder powder metallurgy titanium alloy hot rolling strength and plasticity

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Surface modification by ligand growth strategy for dense copper bismuth film as photocathode to enhance hydrogen production activity

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Frontiers in Energy 2024年第1期18卷 89-100页

作者： Zhouzhou WANG Qingwei WU Jieming WANG ying YU Institute of Nanoscience and Nanotechnology College of Physical Science and TechnologyCentral China Normal UniversityWuhan 430079China

Hydrogen production from photoelectrochemical(PEc)water splitting has been regarded as a promising way to utilize renewable and endless solar ***,semiconductor film grown on photoelectrode suffers from numerous challenges,leading to the poor PEc ***,a straightforward sol-gel method with the ligand-induced growth strategy was employed to obtain dense and homogeneous copper bismuthate photocathodes for PEc hydrogen evolution *** various characterizations,it was found that the nucleation and surface growth of cuBi_(2)O_(4)layer induced by 2-methoxyethanol ligand(2-cuBi_(2)O_(4))demonstrated a decent crystallinity and coverage,as well as a large grain size and a low oxygen vacancy concentration,leading to the good ability of light absorption and carrier ***,under simulated sunlight irradiation(AM1.5G,100 mW/cm^(2)),the 2-cuBi_(2)O_(4)photocathode achieved an enhanced photocurrent density of−1.34 mA·cm^(−2)at 0.4 V versus the reversible hydrogen electrode and a promising applied bias photon-to-current efficiency of 0.586%.This surface modification by ligand growth strategy will shed light on the future design of advanced photoelectrodes for PEc water splitting.

关键词： copper bismuthate photocathode ligand growth strategy dense film PEc

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Recursive Projected Filter Algorithm with Binary-Valued Observations

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Journal of Systems Science & complexity 2024年第5期37卷 1832-1860页

作者： ZHANG Xiaoyan WANG ying XUE Wenchao ZHAO Yanlong Key Laboratory of Systems and control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper focuses on the state estimate for a class of systems with both process noise and measurement noise under binary-valued observations,in which the Gaussian assumption on the predicted density of the state is not required.A recursive projected filter algorithm with time-varying thresholds is constructed to estimate the state under binary-valued *** time-varying thresholds are designed as the prediction value of the measurement,which can provide more information about the system *** convergence property is established with some suitable stability,boundedness and observability *** particular,the estimation error between state and estimate is proved to be asymptotically bounded in the mean-square sense,whose upper bound is related to the variance of process ***,the theoretical results are demonstrated via numerical examples of first-order and high-order systems.

关键词： Binary-valued observations convergence recursive filter time-varying thresholds

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Electroacupuncture at Sensitized Acupoints Relieves Somatic Referred Pain in colitis Rats by Inhibiting Sympathetic-Sensory coupling to Interferewith 5-HT Signaling Pathway

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chinese Journal of Integrative Medicine 2024年第2期30卷 152-162页

作者： YANG ying QU Jin-yu GUO Hua ZHOU Hai-ying RUAN Xia PENG ying-chun SHEN Xue-fang XIONG Jin WANG Yi-li School of clinical Medicine Chengdu Medical CollegeChengdu(610500)China Department of Rehabilitation Medicine the First Affliated Hospital of Chengdu Medical CollegeChengdu(610500)China Department of Rehabilitation Medicine West China HospitalSichuan University/West China School of NursingSichuan UniversityChengdu(610041)China Department of Neurology the First Affiliated Hospital of Chengdu Medical CollegeChengdu(610500)China

Objective:To investigate whether electroacupuncture(EA) at sensitized acupoints could reduce sympathetic-sensory coupling(SSc) and neurogenic inflammatory response by interfering with 5-hydroxytryptamine(5-HT)ergic neural pathways to relieve colitis and somatic referred pain,and explore the underlying ***:Rats were treated with 5% dextran sodium sulfate(DSS) solution for 7 days to establish a colitis *** rats were randomly divided into the control and model groups according to a random number table(n=6).According to the Research on Rat Acupoint Atlas",sensitized acupoints and non-sensitized acupoints were *** were randomly divided into the control,model,Zusanli-EA(ST 36),Dachangshu-EA(BL 25),and Xinshu(BL 15) groups(n=6),as well as the control,model,EA,and EA+GR113808(a 5-HT inhibitor)groups(n=6).The rats in the control group received no *** was administered on 2 days after modeling using the stimulation pavameters:1 mA,2 Hz,for 30 min,with sparse and dense waves,for 14 consecutive ***113808 was injected into the tail vein at 5 mg/kg before EA for 10 min for 7 consecutive *** sensitivity was assessed with von Frey *** weight and disease activity index(DAI) scores of rats were *** and eosin staining was performed to observe colon *** was analyzed by immunofluorescence *** staining was performed to detect 5-HT and substance P(SP) *** calcitonin gene-related peptide(cGRP) in skin tissue and tyrosine hydroxylase(TH) protein levels in DRG were detected by Western *** levels of hyaluronic acid(HA),bradykinin(BK),prostaglandin I2(PGI2) in skin tissue,5-HT,tryptophan hydroxylase 1(TPH1),serotonin transporters(SERT),5-HT 3 receptor(5-HT3R),and 5-HT 4 receptor(5-HT4R) in colon tissue were measured by enzyme-linked immunosorbent assay(ELISA).Results:BL 25 and ST 36 acupoints were determined as sensitized acupoints,and BL 1

关键词： electroacupuncture sensitized acupoints sympathetic-sensory coupling 5-hydroxytryptamine neurogenic inflammation somaticreferredpain

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Interleukins in Epilepsy:Friend or Foe

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Neuroscience Bulletin 2024年第5期40卷 635-657页

作者： Yuan Dong Xia Zhang ying Wang Neuropsychiatry Research Institute The Affiliated Hospital of Qingdao UniversityQingdao UniversityQingdao266000China Program in cellular and Molecular Medicine Boston Children’s HospitalBostonMA02115USA

Epilepsy is a chronic neurological disorder with recurrent unprovoked seizures,affecting~65 million *** in patients with epilepsy and animal models suggests a contribution of neuroinflammation to epileptogenesis and the development of ***(ILs),as one of the major contributors to neuroinflammation,are intensively studied for their association and modulatory effects on ictogenesis and *** are commonly divided into pro-and anti-inflammatory cytokines and therefore are expected to be pathogenic or neuroprotective in ***,both protective and destructive effects have been reported for many *** may be due to the complex nature of ILs,and also possibly due to the different disease courses that those ILs are involved *** this review,we summarize the contributions of different ILs in those processes and provide a current overview of recent research advances,as well as preclinical and clinical studies targeting ILs in the treatment of epilepsy.

关键词： Epilepsy Interleukins Neuroinflammation

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Micro-aluminum powder with bi-or tri-component alloy coating as a promising catalyst:Boosting pyrolysis and combustion of ammonium perchlorate

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Defence Technology（防务技术） 2024年第3期33卷 100-113页

作者： chao Wang ying Liu Mingze Wu Jia Li ying Feng Xianjin Ning Hong Li Ningfei Wang Baolu Shi School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

A novel design of micro-aluminum(μAl)powder coated with bi-/tri-component alloy layer,such as:Ni-P and Ni-P-cu(namely,Al@Ni-P,Al@Ni-P-cu,respectively),as combustion catalysts,were introduced to release its huge energy inside Al-core and promote rapid pyrolysis of ammonium perchlorate(AP)at a lower temperature in aluminized *** microstructure of Al@Ni-P-cu demonstrates that a three-layer Ni-P-cu shell,with the thickness of~100 nm,is uniformly supported byμAl carrier(fuel unit),which has an amorphous surface with a thickness of~2.3 nm(catalytic unit).The peak temperature of AP with the addition of Al@Ni-P-cu(3.5%)could significantly drop to 316.2℃ at high-temperature thermal decomposition,reduced by 124.3℃,in comparison to that of pure AP with 440.5℃.It illustrated that the introduction of Al@Ni-P-cu could weaken or even eliminate the obstacle of AP pyrolysis due to its reduction of activation energy with 118.28 kJ/*** laser ignition results showed that the ignition delay time of Al@Ni-P-cu/AP mixture with 78 ms in air is shorter than that of Al@Ni-P/AP(118 ms),decreased by 33.90%.Those astonishing breakthroughs were attributed to the synergistic effects of adequate active sites on amorphous surface and oxidation exothermic reactions(7597.7 J/g)of Al@Ni-P-cu,resulting in accelerated mass and/or heat transfer rate to catalyze AP pyrolysis and ***,it is believed to provide an alternative Al-based combustion catalyst for propellant designer,to promote the development the propellants toward a higher energy.

关键词： Micro-aluminum powder(μAl) Nano-sized alloy coating combustion catalyst Ammonium perchlorate Pyrolysis behavior Ignition and combustion

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Bacterial persisters: molecular mechanisms and therapeutic development

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3305-3336页

作者： Hongxia Niu Jiaying Gu ying Zhang School of Basic Medical Science and Key Laboratory of Blood-stasis-toxin Syndrome of Zhejiang Province Zhejiang Chinese Medical UniversityHangzhou 310053 ZhejiangChina State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases The First Affiliated Hospital of Zhejiang University School of MedicineHangzhou 310003 ZhejiangChina Jinan Microecological Biomedicine Shandong Laboratory Jinan 250022 ShandongChina

Persisters refer to genetically drug susceptible quiescent(non-growing or slow growing)bacteria that survive in stress environments such as antibiotic exposure,acidic and starvation *** cells can regrow after stress removal and remain susceptible to the same *** are underlying the problems of treating chronic and persistent infections and relapse infections after treatment,drug resistance development,and biofilm infections,and pose significant challenges for effective *** the characteristics and the exact mechanisms of persister formation,especially the key molecules that affect the formation and survival of the persisters is critical to more effective treatment of chronic and persistent ***,genes related to persister formation and survival are being discovered and confirmed,but the mechanisms by which bacteria form persisters are very complex,and there are still many unanswered *** article comprehensively summarizes the historical background of bacterial persisters,details their complex characteristics and their relationship with antibiotic tolerant and resistant bacteria,systematically elucidates the interplay between various bacterial biological processes and the formation of persister cells,as well as consolidates the diverse anti-persister compounds and *** hope to provide theoretical background for in-depth research on mechanisms of persisters and suggest new ideas for choosing strategies for more effective treatmentofpersistent infections.

关键词： mechanisms treatment persist

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