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Propulsion and Power Research 2024年第3期13卷 360-374页

作者： S.W.chen W.H.Li c.xu Q.H.Meng School of Energy Science and Engineering Harbin Institute of TechnologyHarbinHeilongjiang 150001China AVIc Shenyang Aircraft Design and Research Institute Shenyang 110035China

Sweeping jet actuator(SJA)has been widely applied for activeflow control in *** this paper,the SJA character in compressor cascade and its performance for separation control in innerflows are ***-averaged and transientflowfield measurement,together with visualization methods are *** is found that endwall effects are important for both SJA behaviors and SJA performance for separation control in compressor *** is a maximum of 12.7%total pressure loss reduction with SJA placed near the separation position,close to the endwall and under *** characteristic frequencies in theflowfield contribute to the capture of influence regions of vortices and excitation *** concentrated shedding vortices and SJA jets impact region helped to judge that SJA energizes low momentumfluids in a large region and matches the high loss core *** be concrete,theflow separation control mechanism of SJA lies on the interruption of the blade suction surface boundary layer development and the restriction of the lifting of the boundary layer from end-wall towards blade suction surface.

关键词： compressor cascade Activeflow control Sweeping jet actuator corner separation Oilflow visualization

Uncovering the hierarchical clusters in the heat-affected zone of an electron beam weldedα/βtitanium alloy joint

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Journal of Materials Science & Technology 2024年第7期174卷 120-132页

作者： c.xu X.H.Shao H.J.Yang M.Lv H.Q.Liu X.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Suzhou laboratory Suzhou 215028China Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan Bay Area center for Electron Microscopy Songshan Lake Materials LaboratoryDongguan 523808China

Using high-resolution transmission Kikuchi diffraction(TKD)and transmission electron microscopy(TEM),we examined the hierarchical clusters that form in situ in the heat-affected zone(HAZ),which are com-monly referred to as“ghost”structures,of bimodal titanium alloy Ti-5Al-2Sn-2Zr-4Mo-4cr(wt%,Tc17).The ghost structures are enriched with Al elements but poor in Mo and cr compared to the surroundingβ*** results show that the ghost structure in middle-HAZ mainly consists ofα_(L)laths with a high-angle grain boundary,which exhibits the classic Burgers orientation relationship(BOR)with the host matrix,while it encircles theα_(P)grains in *** the ghost structure is evidenced to form via in-complete martensitic *** results further confirm that the ghost structure is composed ofαL and tinyβ_(L)laths with BOR,with the former being enriched with Al and poor with cr and Mo,while the latter is the ***,twoα_(L)variant clusters with a check-mark morphology are fre-quently observed viewed along[0001]_(αL)//[110]_(βL)directions,which are dominated by the crystallographic and geometrical relationships betweenαandβ*** on the microstructural characterization,it is hypothesized that the ghost structure is transformed from the initialα_(P)phase,due to the coupling ef-fect of high thermal stress(which induces the formation of a large number of dislocations)and element diffusion caused by sudden temperature increase and plunge cooling in the HAZ during the welding pro-cess.

关键词： Tc17 titanium alloy Electron beam welding(EBW) The ghost structure Transmission Kikuchi diffraction(TKD) Transmission electron microscopy(TEM)

Recent advances on bismuth oxyhalides for photocatalytic cO_(2)reduction

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Journal of Environmental Sciences 2024年第6期140卷 183-203页

作者： Liangpang xu Jimmy c.Yu Ying Wang Department of chemistry The Chinese University of Hong KongShatinNew TerritoriesHong Kong 999077China

Photocatalytic conversion of cO_(2)into fuels such as cO,cH_(4),and cH_(3)OH,is a promising approach for achieving carbon *** oxyhalides(BiOX,where X=cl,Br,and I)are appropriate photocatalysts for this purpose due to the merits of visible-light-active,efficient charge separation,and easy-to-modify crystal structure and surface *** practical applications,multiple strategies have been proposed to develop high-efficiency BiOX-based *** review summarizes the development of different approaches to prepare BiOX-based photocatalysts for efficient cO_(2)*** the review,the fundamentals of photocatalytic cO_(2)reduction are ***,several widely used modification methods for BiOX photocatalysts are systematacially discussed,including heterojunction construction,introducing oxygen vacancies(OVs),Bi-enrichment,heteroatom-doping,and morphology ***,the challenges and prospects in the design of future BiOX-based photocatalysis for efficient cO_(2)reduction are examined.

关键词： Bismuth oxyhalides Photocatalysis cO_(2)reduction Modification methods

Refractory Ventricular Fibrillation with Underlying coronary Artery Disease after cOVID-19 Vaccine-Kounis Syndrome or coincidence

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case Reports in clinical Medicine 2024年第8期13卷 309-314页

作者： elaine M. c. chau cardiology centre Hong Kong Sanatorium & Hospital Hong Kong SAR China

A 63-year-old man with diabetes and asymptomatic coronary artery disease developed refractory ventricular arrhythmia at 20 hours at rest after his second cOVID-19 vaccine. Despite significant stenosis in the coronary arteries, there was no evidence of acute or old myocardial infarction, heart failure, myocarditis or structural abnormalities on post-mortem to account for the substrate for the fatal arrhythmia. The refractory and incessant nature of the ventricular fibrillation and post-mortem finding of a grossly elevated unexplained IgE level (in the absence of acute myocardial infarction) suggested the possibility of Kounis Syndrome or allergic acute coronary syndrome.

关键词： Refractory Ventricular Fibrillation cOVID-19 Vaccine Kounis Syndrome

Mineral-mediated stability of organic carbon in soil and relevant interaction mechanisms

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Eco-Environment & Health 2024年第1期3卷 59-76页

作者： Zibo xu Daniel c.W.Tsang Department of civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Department of civil and Environmental Engineering The Hong Kong University of Science and TechnologyClear Water BayHong KongChina

Soil,the largest terrestrial carbon reservoir,is central to climate change and relevant feedback to environmental *** are the essential components that contribute to over 60%of soil carbon ***,how the interactions between minerals and organic carbon shape the carbon transformation and stability remains poorly ***,we critically review the primary interactions between organic carbon and soil minerals and the relevant mechanisms,including sorption,redox reaction,co-precipitation,dissolution,polymerization,and catalytic *** interactions,highly complex with the combination of multiple processes,greatly affect the stability of organic carbon through the following processes:(1)formation or deconstruction of the mineral–organic carbon association;(2)oxidative transformation of the organic carbon with minerals;(3)catalytic polymerization of organic carbon with minerals;and(4)varying association stability of organic carbon according to the mineral *** pieces of evidence related to the carbon turnover and stability during the interaction with soil minerals in the real eco-environment are then *** also highlight the current research gaps and outline research priorities,which may map future directions for a deeper mechanismsbased understanding of the soil carbon storage capacity considering its interactions with minerals.

关键词： carbon stability Mineral transformation carbon sequestration Bio-geochemistry Soil carbon management Sustainable waste management

Noncommutative analysis of Hermite expansions

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Science china Mathematics 2024年第10期67卷 2331-2356页

作者： Bang xu Department of Mathematics University of HoustonHoustonTX 77204USA Department of Mathematical Sciences Seoul National UniversitySeoul 08826Republic of Korea

This paper is devoted to the study of semi-commutative harmonic analysis associated with Hermite semigroups. In the first part, we establish the noncommutative maximal inequalities for Bochner-Riesz means associated with Hermite operators and then obtain the corresponding pointwise convergence theorems. In particular, we develop a noncommutative version of Stein's theorem of Bochner-Riesz means for Hermite operators. In the second part, we investigate two noncommutative multiplier theorems. Our approach in this part relies on a noncommutative analog of the classical Littlewood-Paley-Stein theory associated with Hermite semigroups.

关键词： noncommutative L_(p)-spaces Hermite semigroup maximal inequalities pointwise convergence multipliers

Highly Strong,Tough,and cryogenically Adaptive Hydrogel Ionic conductors via coordination Interactions

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Research 2024年第3期2024卷 703-713页

作者： Zhuomin Wang Siheng Wang Lei Zhang He Liu xu xu Institute of chemical Industry of Forestry Products Key Laboratory of Biomass Energy and MaterialJiangsu ProvinceKey Laboratory of Chemical Engineering of Forest ProductsNational Forestry and Grassland AdministrationNational Engineering Research Center of Low-Carbon Processing and Utilization of Forest BiomassJiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesChinese Academy of ForestryNanjing 210042China college of chemical Engineering Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry UniversityNanjing 210037China.

Despite the promise of high flexibility and conformability of hydrogel ionic conductors,existing polymeric conductive hydrogels have long suffered from compromises in mechanical,electrical,and cryoadaptive properties due to monotonous functional improvement strategies,leading to lingering ***,we propose an all-in-one strategy for the preparation of poly(acrylic acid)/cellulose(PAA/cel)hydrogel ionic conductors in a facile yet effective manner combining acrylic acid and salt-dissolved cellulose,in which abundant zinc ions simultaneously form strong coordination interactions with the two polymers,while free solute salts contribute to ionic conductivity and bind water molecules to prevent ***,the developed PAA/cel hydrogel simultaneously achieved excellent mechanical,conductive,and cryogenically adaptive properties,with performances of 42.5 MPa for compressive strength,1.6 MPa for tensile strength,896.9%for stretchability,9.2 MJ m^(−3)for toughness,59.5 kJ m^(−2)for fracture energy,and 13.9 and 6.2 mS cm^(−1)for ionic conductivity at 25 and−70°c,*** by these features,the resultant hydrogel ionic conductor is further demonstrated to be assembled as a self-powered electronic skin(e-skin)with high signal-to-noise ratio for use in monitoring movement and physiological signals regardless of cold temperatures,with hinting that could go beyond high-performance hydrogel ionic conductors.

关键词： Highly freezing salts

Efficient guiding and focusing of intense laser pulse using periodic thin slits

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Matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： L.xu T.W.Huang K.Jiang c.N.Wu H.Peng P.c.hen R.Li H.B.Zhuo c.T.Zhou Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

Enhanced photocatalytic hydrogen production from co-MOF/cN by nitrogen and sulfur co-doped coal-based carbon quantum dots

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Journal of Rare Earths 2024年第5期42卷 838-850,I0002页

作者： Shiyong xu Mei Li Yijun Wang caiyun Gao Rongsheng xu Zhiliang jin School of chemistry and chemical Engineering North Minzu UniversityYinchuan750021China Ningxia Key Laboratory of Solar chemical conversion Technology.North Minzu University.Yinchuan 750021China State Key Laboratory of National Ethnic Affairs commission chemical Technology.North Minzu University Yinchuan750021China

A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NScQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(co-MOF)and graphitic carbon nitride(g-c_(3)N_(4),cN).The structure and properties of the obtained catalysts were systematically *** effectively broaden the absorption of co-MOF and cN in the visible *** new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=*** the same time,NScQDs synergy co-MOF/cN composites have good *** four cycles of hydrogen production,the performance remains relatively *** tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite *** semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was *** conductive and valence bands of cN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of co-MOF are-1.85 and 1.33 eV,*** e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between cN an d co-MOF,and NScQDs was used as cocatalyst.

关键词： Nitrogen and sulfur co-doped coal-based carbon quantum dots co-MOF cN Photocatalytic hydrogen evolution Rare earths

Experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering boundary effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1072-1084页

作者： xuwei Wang Yeshuang xu State Key Laboratory of Ocean Engineering School of Naval ArchitectureOceanand Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure Department of Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China

The boundary condition is a crucial factor affecting the permeability variation due to *** experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering the boundary effect is conducted,where the hydraulic head difference(DH)varies,and the boundary includes non-loss and soil-loss *** samples are filled into seven soil storerooms connected in *** evaluation,the variation in content of fine sand(ΔR_(f))and the hydraulic conductivity of soils in each storeroom(c_(i))are *** the non-loss test,the soil sample filling area is divided into runoff,transited,and accumulated areas according to the negative or positive ΔR_(f) values.ΔR_(f) increases from negative to positive along the seepage path,and ci decreases from runoff area to transited area and then rebounds in accumulated *** the soil-loss test,all soil sample filling areas belong to the runoff area,where the gentle-loss,strengthened-loss,and alleviated-loss parts are further divided.ΔR_(f) decreases from the gentle-loss part to the strengthened-loss part and then rebounds in the alleviated-loss part,and c_(i) increases and then decreases along the seepage *** relationship between ΔR_(f) and ci is different with the boundary *** exponentially decreases with ΔR_(f) in the non-loss test and increases with ΔR_(f) generally in the soil-loss test.

关键词： Suffusion Permeability Experimental investigation Boundary effect Horizontal seepage