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Alignm.nt of inertialess spheroidal particles in flow-structure-dom.nated regions of turbulent channel flow:shape effect

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Acta mechanica Sinica 2024年第8期40卷 45-66页

作者： Zhiwen cui Lihao Zhao Applied mechanics Laboratory Department of Engineering MechanicsTsinghua UniversityBeijing100084China Laboratory of Flexible Electronics Technology Tsinghua UniversityBeijing100084China

The alignm.nt of elongated fibers and thin disks is known to be significantly influenced by the presence of fluid coherent structures in near-wall turbulence(cui et al.2021).However,this earlier study is confined to the spheroids with infinitely large or small aspect ratio,and the shape effect of finite aspect ratio on the alignm.nt is not *** current study investigates the shape-dependent alignm.nt of inertialess spheroids in structure-dom.nated regions of channel *** utilizing an ensemble-averaged approach for identifying the structure-dom.nated regions,we analyze the eigensystem of the linear term matrix in the Jeffery equation,which is governed by both particle shape and local fluid velocity *** contrast to earlier conventional analysis based on local vorticity and strain rate,our findings dem.nstrate that the eigensystem of the Jeffery equation offers a convenient,effective,and universal framework for predicting the alignm.nt behavior of inertialess spheroids in turbulent *** leveraging the eigensystem of the Jeffery equation,we uncover a diverse effect of fluid coherent structures on spheroid alignm.nt with different particle ***,we provide explanations for both shape-independent alignm.nts observed in vortical-core regions and shape-dependent alignm.nts around near-wall streamwise vortices.

关键词： non-spherical particle Direct numerical simulation Wall turbulence Particle-laden flow

OIP5 Interacts with nCK2 to mediate Hum.n Spermatogonial Stem Cell Self-Renewal and Apoptosis through Cell Cyclins and Cycle Progression and Its Abnormality Is Correlated with male Infertility

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Research 2024年第1期2023卷 455-469页

作者： Yinghong cui Wei Chen Li Du Zuping He The Key Laboratory of model Animals and Stem Cell Biology in Hunan Province The Research Center of Reproduction and Translational Medicine of Hunan ProvinceHunan Normal University School of MedicineChangsha 410013HunanChina

Spermatogonial stem cells(SSCs)have important applications in both reproduction and regenerative ***,specific genes and signaling transduction pathways in mediating fate decisions of hum.n SSCs remain ***,we have dem.nstrated for the first time that OIP5(Opa interacting protein 5)controlled the self-renewal and apoptosis of hum.n *** sequencing identified that nCK2 was a target for OIP5 in hum.n SSCs,and interestingly,OIP5 could interact with nCK2 as shown by Co-IP(co-imm.noprecipitation),IP-mS(mass spectrometry),and GST pulldown ***2 silencing decreased hum.n SSC proliferation and DnA synthesis but enhanced their ***,nCK2 knockdown reversed the influence of OIP5 overexpression on hum.n ***,OIP5 inhibition decreased the numbers of hum.n SSCs at S and G2/m phases,while the levels of numerous cell cycle proteins,including cyclins A2,B1,D1,E1 and H,especially cyclin D1,were remarkably ***,whole-exome sequencing of 777 patients with nonobstructive azoospermia(nOA)revealed 54 singlenucleotide polymorphism mutations of the OIP5 gene(6.95%),while the level of OIP5 protein was obviously lower in testes of nOA patients compared to fertile ***,these results implicate that OIP5 interacts with nCK2 to modulate hum.n SSC self-renewal and apoptosis via cell cyclins and cell cycle progression and that its mutation and/or lower expression is correlated with *** such,this study offers novel insights into molecular mechanisms underlying the fate determ.nations of hum.n SSCs and the pathogenesis of nOA,and it provides new targets for treating male infertility.

关键词： OIP5 Apoptosis reversed

Re-entry rocket basic flow characteristics and thermal environm.nt of different retro-propulsion modes

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Chinese Journal of Aeronautics 2024年第7期37卷 190-203页

作者： Yifei SU Peijie SUn Yangwen cui Guigao LE School of mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China Shanghai Institute of Aerospace System Engineering Shanghai 200000China Southwest Institute of Technology and Engineering Chongqing 400039China

During the supersonic re-entry of multi-nozzle heavy rockets into the atmosphere,the basic flow state becomes increasingly complex due to the coupling effect between the retropropulsion plumes and the freestream.A numerical method using the hybrid Reynolds-Averaged navier-Stokes and Large Eddy Simulation(RES)method and discrete coordinate method is developed to accurately estimate the thermal *** addition,finite rate chemical kinetics is used to calculate the afterburning *** numerical results agree well with wind tunnel data,which confirms the validity and accuracy of the numerical *** are conducted for the heavy carrier rocket re-entry from 53.1 km to 39.5 km altitude with 180°angle of attack by using three different Supersonic Retro-Propulsion(SRP)*** numerical results reveal that these three SRP flow fields are all Short Penetration models(SPm).As the re-entry altitudes decrease,both the plume-plume interaction and the plume-freestream interaction become *** highest temperatures in the plume shear layers of the three SRP modes increase by 8.36%,7.33%and 6.92%respectively after considering afterburning reactions,and all occur at a reentry altitude of 39.5 *** the rocket re-enters the atmosphere,the maximum heat flux on the rocket base plate of three SRP modes stabilizes at 290,170 and 200 kW/m^(2) respectively,but the maximum heat flux on the side wall increases *** the altitude declines to 39.5 km,the extreme heat flux of the three modes increase by 84.16%,49.45%and 62.97%respectively compared to that at 53.1 km.

关键词： Re-entry rocket multi-nozzle Supersonic retro propulsion Thermal environm.nt Afterburning effect

Reduction of dinitrogen to amm.nia on doped three-atom clusters nb_(2)m(m=Sc to Cu & Y to Ag)

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Rare metals 2024年第8期43卷 3810-3818页

作者： Ran Cheng Chao-nan cui Zhi-Xun Luo Beijing national Laboratory for molecular Science(BnLmS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Science University of Chinese Academy of SciencesBeijing 100049China

Catalytic reduction of dinitrogen to amm.nia under mild conditions remains an attractive topic for the purpose of lowering energy ***-atom metal clusters have been proved an ideal model to explore highly efficient catalysts taking advantage of unique geometric/electronic structures and cooperative active *** a study of n2 activation and reduction on seventeen bimetallic nb_2m(m=Sc to Cu,and Y to Ag) clusters was *** key processes for amm.nia fixation(namely nitrogen activation,hydrogenation,and amm.nia desorption) are fully studied,and three preferred systems(nb_2ni,nb_2Rh and nb_2Pd) are highlighted with outstanding catalytic *** d-σ and d-π~* orbital hybridizations between these metal clusters and n_(2) were dem.nstrated and the internal association with the n≡n bond activation was *** exam.ning the amm.nia synthesis on four chosen nb_(2)m clusters(m=Fe,ni,Rh and Pd),it can be elucidated that the distal pathway is more favorable than the alternative pathway in these *** work not only clarifies the n_(2) reduction on the bimetallic nb_(2)m clusters,but also guides efficient bimetallic catalyst design.

关键词： Three-atom cluster catalysis Three-criteria strategy nitrogen fixation Amm.nia synthesis Theoretical calculations

Transient features of graphitization and nitrogen-vacancy color centers in a diam.nd fabricated by localization femtosecond laser direct writing

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Science China(Technological Sciences) 2024年第8期67卷 2530-2536页

作者： cui Lin YIn SiYu HU ZiFan WAnG Lei State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

Femtosecond laser direct writing provides an efficient approach to fabricating single nitrogen vacancy(nV) color centers with a relatively high yield. Different from previously reported nV color centers with a random distribution in a bulk diam.nd or nanocrystals, this gives an opportunity to study the photophysical properties of single nV color centers with precise numbers and positions. However, ultrafast studies on single nV color centers prepared by localization femtosecond laser direct writing are still rare, especially for the graphitization inside a diam.nd and its relationship with single nV color centers. Here, we report the broadband transient absorption(TA) spectroscopic features of the graphitization and nV color centers in a diam.nd fabricated by localization femtosecond laser direct writing at room temperature under 400 nm excitation. In comparison with the graphene oxide film, the bleaching features of the graphitization point array in a diam.nd are similar to reduced graphene oxide,accompanied by excited state absorption signals from local carbon atom vacancy defects in graphene-like structures induced by laser writing. On the other hand, transient features of laser processing array containing single nV color centers with a yield of~50% are different from those of the graphitization point array. Our findings suggest that for ultrashort pulse processing of diam.nds, broadband TA spectral signals are sensitive to the surrounding atomic environm.nt of processing sites, which could be applied to laser writing point defects in other materials used as solid-state single photon sources.

关键词： nitrogen-vacancy color center graphitization diam.nd femtosecond laser direct writing ultrafast spectroscopy

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Optical system for extremely large spectroscopic survey telescope

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Science China(Physics,mechanics & Astronomy) 2024年第7期67卷 158-174页

作者： Ding-qiang Su Hua Bai Xiangyan Yuan Xiangqun cui Key Laboratory of the m.nistry of Education School of Astronomy and Space ScienceNanjing UniversityNanjing 210023China nanjing Institute of Astronomical Optics and Technology(nIAOT) Chinese Academy of SciencesNanjing 210042China University of Chinese Academy of Sciences Nanjing 211135China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 101408China

This article presents research work on a spectroscopic survey *** idea is as follows:for such a telescope,a pure reflecting optical system is designed,which should have an aperture and a field of view(FOV)both as large as possible and excellent image quality,and then a strip lensm(lens-prism)atmospheric dispersion corrector(S-ADC)is added,only for correcting the atmospheric *** the fund limitation and the simplicity of scaling up,some 12-m telescopes are designed as ***,Korsch,and meinel put forward the four-mirror nasmyth systems I and II,which are used in this *** of 1.5°,2°,and 2.5°are *** all systems,the image qualities are *** the S-ADC relaxes the optical glass size restriction,this 12-m telescope with a FOV of 2.5°can be magnified in proportion to a 16-m *** etendue(from Frenchétendue)and focal surface will now be the largest in the *** such a telescope,a pure reflecting optical system can also be obtained.A subsequent coudésystem is designed with excellent image quality.

关键词： telescopes spectroscopic survey

Spatial distribution of shallow landslides caused by Typhoon Lekima in 2019 in Zhejiang Province, China

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Journal of mountain Science 2024年第5期21卷 1564-1580页

作者： cui Yulong YAnG Liu XU Chong ZHEnG Jun School of Civil Engineering and Architecture Anhui University of Science and TechnologyHuainan 232001China national Institute of natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Departm.nt of Civil Engineering Zhejiang UniversityHangzhou 310058China

In recent years, the coastal region of Southeast China has witnessed a significant increase in the frequency and intensity of extreme rainfall events associated with landfalling typhoons. The hilly and mountainous terrain of this area, combined with rapid rainfall accumulation, has led to a surge in flash floods and severe geological hazards. On August 10, 2019, Typhoon Lekima made landfall in Zhejiang Province, China, and its torrential rainfall triggered extensive landslides, resulting in substantial damage and economic losses. Utilizing high-resolution satellite images, we compiled a landslide inventory of the affected area, which comprises a total of 2,774 rainfallinduced landslides over an area of 2965 km2. The majority of these landslides were small to mediumsized and exhibited elongated, clustered patterns. Some landslides displayed characteristics of high-level initiation, obstructing or partially blocking rivers, leading to the formation of debris dams. We used the inventory to analyze the distribution pattern of the landslides and their relationship with topographical, geological, and hydrological factors. The results showed that landslide abundance was closely related to elevation, slope angle, faults, and road density. The landslides were predom.nantly located in hilly and low mountainous areas, with elevations ranging from 150 to 300 m, slopes of 20 to 30 degrees, and a nE-SE aspect. notably, we observed the highest Landslide number Density(LnD) and Landslide Area Percentage(LAP) in the rhyolite region. Landslides were concentrated within approximately 4 km on either side of fault zones, with their size and frequency negatively correlated with distances to faults, roads, and river systems. Furthermore, under the influence of typhoons, regions with denser vegetation cover exhibited higher landslide density, reaching maximum values in shrubland areas. In areas experiencing significantly increased concentrated rainfall, landslide density also showed a corr

关键词： Typhoon rainfall Landslide characteristics Spatial distribution Southeast coastal region

Engineering biomimetic nanosystem targeting multiple tumor radioresistance hallmarks for enhanced radiotherapy

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Science China(Life Sciences) 2024年第7期67卷 1398-1412页

作者： Shuxiang Wang Hongmei Cao cui-cui Zhao Qian Wang Dianyu Wang Jinjian Liu Lijun Yang Jianfeng Liu State Key Laboratory of Advanced medical materials and Devices Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear MedicineKey Laboratory of Radiopharmacokinetics for Innovative DrugsTianjin Institutes of Health ScienceInstitute of Radiation MedicineChinese Academy of Medical Sciences&Peking Union Medical CollegeTianjin 300192China Tianjin medical University Cancer Institute and Hospital National Clinical Research Center for CancerTianjin’s Clinical Research Center for CancerKey Laboratory of Cancer Prevention and Therapy(Tianjin)Key Laboratory of Breast Cancer Prevention and TherapyTianjin Medical UniversityMinistry of EducationTianjin 300060China

Tumor cells establish a robust self-defense system characterized by hypoxia,antioxidant overexpression,DnA damage repair,and so forth to resist *** one of these features is insufficient to overcome radioresistance due to the feedback mechanisms initiated by tumor cells under ***,we herein developed an engineering biomimetic nanosystem(m@HHPt)masked with tumor cell membranes and loaded with a hybridized protein-based nanoparticle carrying oxygens(O_(2))and cisplatin prodrugs(Pt(Ⅳ))to target multiple tumor radioresistance hallmarks for enhanced *** adm.nistration,m@HHPt actively targeted and smoothly accumulated in tumor cells by virtue of its innate hom.ng abilities to realize efficient co-delivery of O_(2)and Pt(Ⅳ).O_(2)introduction induced hypoxia alleviation cooperated with Pt(Ⅳ)reduction caused glutathione consumption greatly amplified radiotherapy-ignited cellular oxidative ***,the released cisplatin effectively hindered DnA damage repair by crosslinking with radiotherapy-produced DnA ***,m@HHPt-sensitized radiotherapy significantly suppressed the proliferation of lung cancer H1975 cells with an extremely high sensitizer enhancem.nt ratio of 1.91 and the progression of H1975 tumor models with an excellent tumor inhibition rate of 94.7%.Overall,this work provided a feasible strategy for tumor radiosensitization by overcom.ng multiple radioresistance mechanisms.

关键词： biomimetic nanosystem hypoxia alleviation glutathione consumption oxidative stress amplification DnA damage fixation radiosensitization

Hot-exciton effects on exciton diffusion and circular polarization dynamics in a single PbI_(2)nanoflake

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Science China(Technological Sciences) 2024年第1期67卷 83-90页

作者： XU ChenYu WAnG Lei cui Lin GAO BingRong WAnG HaiYu State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

As one of the emerging two-dim.nsional lead halide materials,lead iodide(PbI_(2))nanosheets have proven to possess strong application potential in the fields of high-energy radiation detection and highly efficient perovskite solar ***,the underlying photophysical properties such as hot-exciton-related carrier dynamics remain unclear for PbI_(2)***,we report the exciton dynamics of a single PbI_(2)nanoflake prepared by an aqueous solution *** a three-dim.nsional(3D)diffusion model,we obtain the exciton annihilation radius and diffusion coefficient of a single PbI_(2)nanoflake under nonresonant and resonant excitation conditions of band-edge exciton *** initial exciton densities increase,we find the carrier recombination mechanism for a single PbI_(2)nanoflake gradually changes from exciton-exciton annihilation to free-carrier ***,we reveal the room-temperature circular polarization of a single PbI_(2)nanoflake is due to free-carrier recombination with a band-edge exciton dissociation time of~120 fs under the resonant excitation condition.

关键词： single PbI_(2)nanoflake exciton diffusion room-temperature circular polarization ultrafast spectroscopy