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Suppression of vortex rope oscillation and pressure vibrations in Francis turbine draft tube using various strategies

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Journal of Hydrodynamics 2021年第3期33卷 534-545页

作者： Lei Zhu Rui-zhi Zhang An Yu Li Lu xian-wu luo China Institute of Water Resources and Hydropower Research Beijing100038China State Key Laboratory of Hydroscience and Engineering Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China College of Energy and Electrical Engineering Hohai UniversityNanjing210098China

The vortex rope usually occurs in the draft tube of the Francis turbine operated under part-load conditions,to induce strong low-frequency pressure vibrations,and therefore,is very harmful to the safety of the hydropower *** the present work,three kinds of strategies are extensively investigated,i.e.,the installations of the ventilation and the fin,as well as the hybrid strategy of the air admission through a fin,so as to effectively suppress the vortex rope oscillation and the pressure vibration in the draft tube of a Francis turbine,whose specific speed is 125 *** the unsteady flow simulation,the Reynolds averaged Navier-Stokes(RANS)method is applied coupled with the k-ω SST turbulence model and a homogeneous cavitation *** flow analysis confirms that the low-frequency pressure vibrations are originated from the periodical oscillation of the vortex rope,and the cavitation usually enhances the vortex rope oscillation in the draft *** the part-load condition,the dominant component of the pressure vibration in the draft tube has a frequency,for example,f_(1),lower than the runner rotating frequency f_(n).It is shown that all three strategies can be adopted to alleviate the vortex rope oscillation and the pressure vibrations in the draft tube,but their suppression mechanisms are quite *** ventilation of an adequate amount from the turbine runner cone can change the vortex rope geometry from the spiral type to the cylindrical type,suppress the vortex rope oscillation,and consequently create the homogeneous distributions of the pressure and the pressure gradient in the draft *** the other hand,a fin installed at the draft tube wall can induce a small extra rope,and the interaction between the main vortex rope and the extra rope changes the flow field and alleviates the pressure vibration in the draft *** should be noted that a fin is much more effective to suppress the pressure vibration in the draft tube under the cavitation cond

关键词： Francis turbine vortex rope pressure vibration ventilation fin installation

Formation and strengthening mechanism of kink bands in an ultra-coarse-grained Fe-Cr-Al alloy

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Journal of Materials Science & Technology 2024年第19期186卷 1-14页

作者： Wei luo Teng Xue Ding Zuo Jingze Cheng zhe Liu Huiqun Liu School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Fe-Cr-Al alloys,owing to their absence of allotropic transformation,require multiple cycles of rolling and recrystallization annealing processes to achieve substantial grain refinement,ultimately leading to the attainment of outstanding mechanical ***,the corresponding manufacturing costs will also increase *** this work,we have proposed a new microstructural preparation ***-ply using warm rolling for an ultra-coarse-grained Fe-Cr-Al alloy to introduce lamellar kink bands(KBs)into the matrix,the mechanical properties can be significantly *** using electron backscatter diffraction(EBSD)and transmission electron microscopy(TEM),and combined with Schmid factor(SF)calculation,the formation mechanism of KBs has been *** the slip plane and direction are nearly perpendicular to the loading force direction(LFD)during the continuous grain rotation,the dislo-cation wall will evolve into the KBs ***,a huge orientation separation between the matrix and KBs will be *** strain continues to rise,KBs undergo a transformation,tran-sitioning from low-angle-grain boundaries(LAGBs)to high-angle-grain boundaries(HAGBs),occasionally adopting a configuration as coincident site lattice(CSL)boundaries with reduced interface ***-sults of the tensile test,cyclic loading-unloading-reloading tensile test,and the strengthening calculation show that KBs can pronouncedly enhance the strength by their heterogeneous refinement on the original grains and hetero-deformation induced(HDI)strengthening effect from the dislocation density discrep-ancy between the matrix and internal KBs,the grains containing KBs(KBGs)and the grains without KBs(or KBs-free-grains,KFGs).The theoretical calculation value of the strengthening contribution from KBs on yield strength can be up to 225.5 MPa,with a minimum value exceeding 153 *** the other hand,the ductility can be retained to some extent through stimulating the KBs boundary de

关键词： Fe-Cr-Al alloy Kink bands(KBs) Heterogenous refinement Hetero-deformation induced(HDI) strengthening KBs boundary delamination

Flexible aqueous Ca-ion full battery with super-flat discharge voltage plateau

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Nano Research 2022年第1期15卷 701-708页

作者： Panpan Wang Hua Wang zhe Chen Junwei Wu Jingting luo Yan Huang School of Materials Science and Engineering Shenzhen UniversityShenzhen 518055China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyShenzhen 518055China Flexible Printed Electronic Technology Center Harbin Institute of TechnologyShenzhen 518055China School of Materials Science and Engineering Harbin Institute of TechnologyShenzhen 518055China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518055China

Recently,multivalent metal-ion batteries have attracted considerable interests on the merits of their natural abundance and multielectron redox ***,the development of Ca-ion battery is still in their preliminary stage because of the lack of suitable electrode *** Ca-storage performance of the existing materials is still unsatisfactory with low capacity,poor cyclic stability,as well as sloping discharge profiles,which cannot provide stable energy *** this work,transition metal oxide Sn-doped In2O3(ITO)has been explored as the aqueous Ca-ion battery anode,which could deliver a high discharge capacity of 71.2 mAh·g^(-1) with an ultra-flat discharge voltage *** Ca storage mechanism was revealed to be reversible conversion reaction based on ex-situ X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron microscopy(TEM)characterizations.A flexible aqueous Ca-ion battery was subsequently assembled with zinc hexacyanoferrate(ZnHCF)cathode and ITO anode sandwiched by hydrogel electrolyte,which could deliver a high specific capacity of 75.3 mAh·g^(-1) at 0.4 A·g^(-1) with a flat output voltage plateau at around 0.8 *** bendable and flexible Ca-ion battery with decent voltage output will pave the way for the energy storage devices towards practical applications in flexible and wearable electronics.

关键词： multivalent metal ion battery aqueous Ca-ion battery voltage plateau ln2O3(ITO) flexible and wearable

A facile approach to fabricating graphene/waterborne epoxy coatings with dual functionalities of barrier and corrosion inhibitor

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Journal of Materials Science & Technology 2022年第17期112卷 263-276页

作者： Suyun Liu Xuewan Wang Qi Yin Xiongzhi xiang xian-Zhu Fu xian-Zong Wang Jing-Li luo Shenzhen Key Laboratory of Polymer Science and Technology Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China

A facile and environmentally-friendly method is developed to prepare graphene/waterborne epoxy(WEP)composite *** graphene nanosheets are produced with electrochemical-exfoliation in the solution containing surfactants,cetyl trimethyl ammonium bromide(CTAB)and sodium dodecyl sulfate(SDS).The nanosheets containing solution thus formed are subjected to a quick dialysis and then directly used as a diluent for WEP without any further *** preparation method overcomes the commonly identified problems of aggregations and‘corrosion promotion’effect associated with graphene,and increases the impedance of the composite coatings by more than two orders of *** analysis of anticorrosion performance suggested that the presence of surfactants not only improves the dispersibility of graphene nanosheets but also endows the composite coatings with both barrier and corrosion inhibition *** strategy reported herein may pave the path to the large-scale production of graphene anticorrosion coatings.

关键词： Electrochemical-exfoliation graphene Waterborne epoxy coatings Anticorrosion Inhibition

Microstructure Evolution and Nanomechanical Behavior of Micro-Area in Molten Pool of Selective Laser Melting(CoCrNi)_(82)Al_(9)Ti_(9)High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1019-1033页

作者： Hong-Wei Zhang Li-Wei Lan zhe-Yu Yang Chang-Chun Li Wen-xian Wang College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyTaiyuan030024China Shanxi-zhejiang University New Materials and Chemical Research Institute Taiyuan030032China

In this work,the phase evolution mechanism and nanomechanical properties of(CoCrNi))(82)Al_(9)Ti_(9)high-entropy alloy(HEA)prepared by selective laser melting(SLM)in the molten pool were *** HEA contains multiple primary elements and undergoes high-temperature gradient and rapid cooling during *** leads to significant inhomogeneity of nano-scale microstructure characteristics and instability of *** optimizing process parameters,the microstructure evolution at the optimal parameter volume energy density of 440 J/mm^(3)was studied.A phase transition from BCC to FCC occurred in the melt *** the micro-area of the melt pool results in a temperature rise and the combustion-induced loss of Al ***,the Ni element content increases significantly outside the melt *** process enhances the phase stability of FCC and facilitates phase ***,rapid cooling leads to the formation of distinctive ultrafine equiaxial crystals inside the melt pool,accompanied by the generation of intracrystalline needle-like nano-scale *** the melt pool,the accumulation of energy results in the formation of coarse ***,the nano-hardness inside the molten pool is remarkably high at 11.79 GPa,while the outside the molten pool is reduced to 9.58 *** the fracture toughness outside the melt pool also *** with inside the melt pool,the residual stress outside the melt pool changed from compressive to tensile stress and decreased from 603.28 to 322.84 MPa.

关键词： High-entropy alloys Selective laser melting Microstructure evolution Nanoindentation

Identification and Quantitative Analysis of Significantly Accumulated Proteins During the Arabidopsis Seedling De-etiolation Process

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Journal of Integrative Plant Biology 2006年第1期48卷 104-113页

作者： Bai-Chen Wang Ying-Hong Pan Da-zhe Meng Yu-xian Zhu The National Laboratory of Protein Engineering and Plant Genetic Engineering College of Life Sciences Peking University Beijing 100871 China

Proteomic analysis was performed on seedlings after different light treatments. A total of （1 350±31） protein spots was separated and visualized on each silver nitrate-stained two-dimensional gel using protein samples prepared from light-grown or etiolated seedlings with or without 6-9 h light treatment. Twenty-five protein spots （encoded by 19 genes） that were significantly accumulated upon light treatment were identified using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry method. Functional proteomics indicated that these proteins involved mainly in chloroplast development, energy metabolism, cell cycle progression and membrane electron transport. For 18 of the protein-coding genes we identified through an internet search, the transcript levels of 17 genes matched roughly with their protein content in etiolated and green seedlings, suggesting that these genes were regulated by light mainly at the transcriptional level. Despite a very significant increase in the amount of proteins upon light treatment, similar RNA levels were found in dark-grown or green seedlings for the carbonic anhydrase gene At3g05100, indicating a possible post-transcriptional regulatory mechanism. Elucidation of light-induced protein accumulation will undoubtedly enhance our understanding of plant photomorphogenesis.

关键词： Arabidopsis de-etiolation light two-dimensional electrophoresis.

Study of Local Structural Changes on Air Cooling at the End of Rotor Windings for Variable Speed Pumped Storage Generator-Motor

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Energy Engineering 2022年第6期119卷 2243-2254页

作者： Yanliang Qiu Bin Xiong zhe Hou Lin luo University of Chinese Academy of Sciences Beijing100049China Institute of Electrical Engineering of Chinese Academy of Sciences Beijing100049China Dongfang Electric Machinery Co. Ltd.Deyang618000China

The shrink fit retaining ring is currently the easiest to install and the most widely used end fixed for structure AC excitation variable speed generator-motor rotor end ***,the current research on the effect of high strength sealing on the ventilation and heat dissipation performance of the end is not *** this paper,based on the actual structural parameters and periodic symmetry simplification,the three-dimensional coupled calculation model of fluid field and temperature field is *** solving the fluid and thermal equations,the influence of the length of rotor support block,the height of rotor support block,and the number of rotor support block on the fluid flow and temperature distribution in the rotor end region of generator-motor is studied using the finite volume *** rheological characteristics of the air in the rotor domain,such as velocity and inter-winding flow,are *** law of temperature variation with local structure in the computational domain is *** variation law of cooling medium performance inside the large variable speed power generator motor is revealed.

关键词： Pumped storage plants generator-motor local structural changes rotor windings end

Study of Oxidation of Glutathione Treated with Hypochlorous Acid by Capillary Electrophoresis

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Chinese Chemical Letters 2001年第7期12卷 623-624页

作者： xian luo Jian De LU Xiao Yun FU Analytical and Testing Center Zhejiang UniversityHangzhou 310027

Capillary electrophoresis (CE) method was developed for the separation and quantification of reduced glutathione (GSH), oxidized glutathione (GSSG) and glutathione sulphonic acid (GSO(3)H). Baseline separation was obtained within five minutes. The effects of reaction time and molar ratio of hypochlorous acid (HOCl) to GSH on the oxidation of GSH were investigated.

关键词： Glutathione oxidation capillary electrophoresis

Hemoglobin loss method calculates blood loss during pancreaticoduodenectomy and predicts bleeding-related risk factors

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World Journal of Gastrointestinal Surgery 2024年第2期16卷 419-428页

作者： Chao Yu Yi-Min Lin Guo-zhe xian Department of Hepatobiliary Surgery Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021Shandong ProvinceChina

BACKGROUND The common clinical method to evaluate blood loss during pancreaticoduoden-ectomy(PD)is visual inspection,but most scholars believe that this method is extremely subjective and ***,there is no accurate,objective me-thod to evaluate the amount of blood loss in PD *** retrospectively analyzed the clinical data of 341 patients who underwent PD in Shandong Provincial Hospital from March 2017 to February *** to different surgical methods,they were divided into an open PD(OPD)group and a laparoscopic PD(LPD)*** differences and correlations between the in-traoperative estimation of blood loss(IEBL)obtained by visual inspection and the intraoperative calculation of blood loss(ICBL)obtained using the Hb loss method were ***,IEBL and perioperative calculation of blood loss(PCBL)were compared between the two groups,and single-factor regression analysis was *** There was no statistically significant difference in the preoperative general patient information between the two groups(P>0.05).PD had an ICBL of 743.2(393.0,1173.1)mL and an IEBL of 100.0(50.0,300.0)mL(P200μmol/L(95%CI:7.09-644.26;P=0.045)were independent risk factors for *** ICBLs of the LPD group and OPD group were 767.7(435.4,1249.0)mL and 663.8(347.7,1138.2)mL,respectively(P>0.05).The IEBL of the LPD group 200.0(50.0,200.0)mL was slightly greater than that of the OPD group 100.0(50.0,300.0)mL(P>0.05).PCBL was greater in the LPD group than the OPD group[1061.6(612.3,1632.3)mL vs 806.1(375.9,1347.6)mL](P<0.05).CONCLUSION The ICBL in patients who underwent PD was greater than

关键词： Pancreaticoduodenectomy Hemoglobin loss Calculated blood loss Estimated blood loss