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A symmetry-based length model for characterizing the hypersonic boundary layer transition on a slender cone at moderate incidence

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Advances in Aerodynamics 2022年第1期4卷 546-568页

作者： wei-tao bi Zhou wei Ke-Xin Zheng Zhen-Su She State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing100871China Science and Technology on Scramjet Laboratory China Aerodynamics Research and Development CenterMianyang621000China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang621000China Computational Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang621000China

The hypersonic boundary layer(HBL)transition on a slender cone at moderate incidence is studied via a symmetry-based length model:the SED-SL *** SED-SL specifies an analytic stress length function(which defines the eddy viscosity)describing a physically sound two-dimensional multi-regime structure of transitional boundary *** studies showed accurate predictions,especially on the drag coefficient,by the SED-SL for airfoil flows at different subsonic Mach numbers,Reynolds numbers and angles of ***,the SED-SL is extended to compute the hypersonic heat transfer on a 7∘half-angle straight cone at Mach numbers 6 and 7 and angles of attack from 0∘to 6∘.It is shown that a proper setting of the multi-regime structure with three parameters(i.e.a transition center,an after-transition near-wall eddy length,and a transition width quantifying transition overshoot)yields an accurate description of the surface heat fluxes measured in wind *** good agreements between simulations and measurements are obtained from windward to leeward side of the cone,implying the validity of the multi-regime description of the transition independent of instability *** is concluded that a unified description for the HBL transition of cone is found,and might offer a basis for developing a new transition model that is simultaneously of computational simplicity,sound physics and greater accuracy.

关键词： Hypersonic boundary layer transition Transition model Cone Heat flux

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Numerical simulations of compressible mixing layers with a discontinuous Galerkin method

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Acta Mechanica Sinica 2011年第3期27卷 318-329页

作者： Xiao-Tian Shi Jun Chen wei-tao bi Chi-Wang Shu Zhen-Su She State Key Laboratory for Turbulence and Complex Systems and Dept. Mechanical and Aerospace Engineering College of EngineeringPeking University100871 BeijingChina Division of Applied MathematicsBrown UniversityProvidence RI 02912USA Division of Applied Mathematics Brown University Providence RI 02912 USA

Discontinuous Galerkin（DG） method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is developed for numerical simulations of both temporally and spatially developing mixing layers. For the temporally developing mixing layer,both the instantaneous fiow field and time evolution of momentum thickness agree very well with the previous results. Shocklets are observed at higher convective Mach numbers and the vortex paring manner is changed for high compressibility. For the spatially developing mixing layer,large-scale coherent structures and self-similar behavior for mean profiles are investigated. The instantaneous fiow field for a three-dimensional compressible mixing layer is also reported,which shows the development of largescale coherent structures in the streamwise direction. All numerical results suggest that the DG method is effective in performing accurate numerical simulations for compressible shear fiows.

关键词： Compressible mixing layer - Discontinuous Galerkin method . Self-similarity . Coherent structure

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Spectral modulation and supercontinuum generation assisted by infrared femtosecond plasma grating

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Chinese Physics B 2013年第7期22卷 359-363页

作者：刘作业孙少华史彦超丁鹏基刘情操刘小亮丁宝卫胡碧涛 School of Nuclear Science and Technology Lanzhou University

Spectral modulation and supercontinuum generation of a probe pulse is investigated by using the plasma grating induced by the interference of two infrared femtosecond laser pulses. The dependences of the supercontinuum generation from the probe pulse on the time delay, the relative polarization angle between the probe pulse and the two-pump pulses, and the input probe pulse energy are investigated. The far-field spatial profiles of the three pulses are measured with different time delays and relative polarization angle, and the core energy of the probe pulse as functions of the time delay and relative polarization angle are also shown.

关键词： plasma grating supercontinuum generation redistribution of refractive index

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High-precision tip positioning composite feedforward control of linear colocated motion systems with bi-Loop iterative feedforward tuning

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Science China Technological Sciences 2025年

作者： Junyu HU Yourui tao Shanhu LI Xu HAN College of Mechanical and Vehicle Engineering Hunan University State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology

To enhance the tip positioning accuracy and robustness against disturbances of linear colocated motion systems, a novel composite feedforward (COMFF) control with bi-Loop iterative feedforward tuning (IFFT) is proposed. The tip positioning error consists of the coupled tip residual vibration and linear motor tracking error. Given the influence of nonlinear friction and load flexibility, the topology of COMFF is designed as decoupled structures so that COMFF can suppress the tip residual vibration and compensate for the linear motor tracking error compatibly. Furthermore, bi-Loop IFFT is built to improve the robustness of COMFF in high-precision motor tracking performance. In the state space of the linear motor tracking error based on the projection theorem, two loops are performed in parallel along the iteration direction. One is the P-type iteration loop that drives linear motor tracking errors to converge to the zero state. The other is the observation loop constructed by the recursive least square with forgetting factors to accelerate the P-type iteration loop. Driven by the P-type iteration loop with the aid of the observation loop, the proposed COMFF is integrated with fast convergence and high robustness when confronted with model disturbances. The effectiveness of the proposed COMFF combined with bi-Loop IFFT is validated by experiments.

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Performance enhancement of perovskite solar cells with Cs2PtI6-xBrx absorber layer based on numerical simulation

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Optoelectronics Letters 2025年

作者： Du Zuyan Yuan Yujie Hou Guofu Xin Yupeng bi Jinlian Li wei Tianjin Key Laboratory of Film Electronic and Communication Devices， School of Integrated Circuit Science and Engineering， Tianjin University of Technology Institute of Photoelectronic Thin Film Devices and Technology， Nankai University

Cs2TiBr6， characterized as a lead-free vacancy-ordered double perovskite material， demonstrates notable stability and photoelectric performance， rendering it suitable for application in perovskite solar cells. However， the experimental efficiency of this material is currently limited， achieving only 3.12%. This efficiency limitation primarily stems from the material’s wide bandgap， which results in insufficient light absorption. To address this issue， this study utilized Cs2PtI6-xBrxfor band structure fine-tuning. By adjusting the bandgap of Cs2PtI6-xBrxthrough Br-doping， not only was the alignment of the energy bandgap in the absorption layer effectively adjusted， but the cutoff range of light absorption was also significantly expanded. Setting the Cs2PtI6-xBrxbandgap to 1.4 eV resulted in optimal device performance. Additionally， comparative analyses aimed at boosting solar cell efficiency were performed on both hole transport and electron transport layer materials. Subsequently， the structure of the perovskite solar cell was optimized using an FTO/TiO2/Cs2TiBr6/Cs2PtI6-xBrx/Cu2O/Au configuration. Furthermore， the influence of the absorber layer thickness and defect density on device performance was studied. Ultimately， this configuration enabled the Cs2TiBr6/Cs2PtI6-xBrxsolar cell to achieve a peak conversion efficiency of 29.69%.

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Modular assembly of Co4-thiacalix[4]arene units and Keggin-type SiW12O40 for visible-light photothermal conversion

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Tungsten 2025年第1期7卷 112-119页

作者： Jia-Hui Li Qing Zhao Dong-Ao Mao Kun Zhou Bao-Kuan Chen Yan-Feng bi School of Petrochemical Engineering Liaoning Petrochemical University

The construction of metal-organic coordination clusters（MCCs） using modular secondary building units is an important method for preparing functional *** this study,two new MCCs modularly assembled from Keggin-type {SiW12O40}H4TC4A=p-tert-Butylthiacalix[4]arene(SiW12) units and thiacalixarene-supported Co4-thiacalix[4]arene(Co4-TC4A polynuclear second-building units（PSBUs,H4TC4A=p-tert-Butylthiacalix[4]arene） are *** two MCCs,abbreviated as Co4-SiW12and Co8-SiW12,were structurally characterized by single-crystal X-ray *** Co4-SiW12is a supramolecular structure involving cation-anion interactions between Co4-TC4A PSBUs and ***8-SiW12features "barbell-like" shapes with two Co4-TC4A coordinatively linked to a Keggin-type SiW12unit on opposite via W-O_t-Co *** coordination of Co4-TC4A to SiW12in Co8-SiW12resulted in significantly improved photothermal conversion performances compared with Co4-SiW12and pure SiW12or ***-gap determination and photophysical analysis combined with density functional theory calculations indicated the binding mode between Co4-TC4A PSBUs and SiW12,which considerably influences the way of electron transport and the conversion ability of visible light to heat.

关键词： Modular construction Photothermal conversion Polyoxometalate Thiacalixarene

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Robust interface and excellent as-built mechanical properties of Ti–6Al–4V fabricated through laser-aided additive manufacturing with powder and wire

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 154-168页

作者： Fei Weng Guijun bi Youxiang Chew Shang Sui Chaolin Tan Zhenglin Du Jinlong Su Fern Lan Ng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong Engineering&Technology Research Center for Superhard MaterialSchool of Materials Science and EngineeringShandong UniversityJinan 250061China Institute of Intelligent Manufacturing Guangdong Academy of SciencesGuangzhou 510095China Singapore Institute of Manufacturing Technology 5 Cleantech Loop636732Singapore

The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),*** the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire *** characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α *** mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and *** mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat *** fracture occurred within the interfacial area,further suggesting the robust *** findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.

关键词： laser-aided additive manufacturing powder deposition wire deposition interfacial characteristic mechanical behavior

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High-precision magnetic field measurement system based on a coherent population trapping magnetometer onboard the SATech-01 satellite

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Science China Technological Sciences 2025年

作者： Hongbo XUE wei SONG Haoran ZHAO Yiteng ZHANG Shanzhi YE Jindong WANG Ran tao Peng SANG Keli CHEN Xingzi bi bingjun CHENG bin ZHOU Yongliang XUE Yingying TANG Liu LIU Jinsong LI Xiaocheng ZHU Baoquan LI Jinguo LIU Wen CHEN Xiaofeng ZHANG Yonghe ZHANG Lei LI State Key Laboratory of Space Weather National Space Science Center Chinese Academy of Sciences Key Laboratory of Solar Activity and Space Weather National Space Science Center Chinese Academy of Sciences Key Laboratory of Electronics and Information Technology for Space Systems National Space Science Center Chinese Academy of Sciences State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Innovation Academy for Microsatellites Chinese Academy of Sciences

On July 27, 2022, a high-precision system for measuring the magnetic field based on a coherent population trapping magnetometer（referred to as the CPT system） was launched onboard the Space Advanced Technology demonstration satellite（SATech-01） by a ZK-1A rocket. The payload comprises a scalar coherent population trapping magnetometer（CPTM）, triaxial anisotropic magnetoresistance magnetometer（AMRM）, and nano star tracker mounted on a non-magnetic telescopic tubular mast. This configuration enables synchronized measurement of scalar and vector geomagnetic fields, as well as the attitude,making the payload with its compact sensors suitable for applications on miniature satellite platforms. On November 7, 2022,the novel telescopic tubular mast was deployed in orbit, extending to a length of 5.28 m. The CPTM, an absolute scalar magnetometer with an omnidirectional sensor, is the first China-developed quantum/atomic magnetometer successfully operating in space. In orbit, the CPTM has sensitivity of ～10 pT/Hz1/2and can automatically operate under complex magnetic field variations. The difference between the scalar fields obtained using the CPTM and CHAOS model has a mean deviation of–3.73 n T and a standard deviation of 26.11 nT（1σ）, without on-orbit calibration or correction. The miniaturized AMRM has a sensitivity of ～0.3 n T/Hz1/2and maintains stable and reliable operation in orbit. The low-power and miniaturized nano star tracker has a measurement uncertainty of 14.23″（1σ） in orbit. The mission has realized the on-orbit technical verification of the integrated and synchronized detection of the vector magnetic field and attitude and fully validated the system's performance,automation level, and reliability.

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Neural cell cycle dysregulation and central nervous system diseases

Neural cell cycle dysregulation and central nervous system d...

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中国神经科学学会第四次会员代表大会暨第八届全国学术会议

作者： wei WANG,bi-tao BU,Min-Jie XIE,Min ZHANG,Zhi-Yuan YU,De-Ding tao~2 1 Department of Neurology,Tongji Hospital,Tongji Medical College,Huazhong,University of Science and Technology, Wuhan,430030,China 2 Molecular Medicine Center,Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology, Wuhan,430030,China

＜正＞The cell cycle is a delicately manipulated process essential for the development,differentiation,proliferation and death of *** activation of cell cycle regulators is implicated in the pathophysiology of a wide range of central nervous system（CNS） diseases,including both acute damage and chronic neurodegenerative *** cycle activation induces the dividing astrocytes and microglia to activate and proliferate in association with glial scar formation and inflammatory factor production,which play crucial roles in the development of pathology in CNS *** the other hand,in terminally differentiated neurons,aberrant reentry into the cell cycle triggers neuronal death instead of proliferation,which may be a common pathway shared by some acquired and neurodegenerative disorders,even though multiple pathways of the cell cycle machinery are involved in distinct neuronal demise in specific pathological circumstances. In this paper,we first provide a concise description of the roles of cell cycle in neural *** then focus on how neural cell cycle dysregulation is related to CNS *** apoptosis is often detected in acute injury to the CNS such as stroke and trauma,which are usually related to the blockade of the cell cycle at the G1-S *** neurodegenerative diseases such as Alzheimer’s disease,Parkinson’s disease,amyotrophic lateral sclerosis and Niemann-Pick disease type C,however,some populations of neurons complete DNA synthesis but the cell cycle is arrested at the G2/M transition. This review summarizes advances in findings implicating cell cycle machinery in neuronal death in CNS diseases.

关键词： cell cycle glia neuron apoptosis ischemia neurodegeneration

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Photosynthetic reaction pathways of natural and artificial systems

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Science China Chemistry 2025年

作者： Shixing Lei Liting bi Lingxuan Chen Zhanting Li Jia Tian State Key Laboratory of Organometallic Chemistry and Shanghai Hong Kong Joint Laboratory in Chemical Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences

Photosynthesis converts solar energy into chemical energy through highly coordinated photosynthetic *** by natural systems,artificial photosynthesis aims to develop an efficient,sustainable,and cost-effective pathway for solar-tochemical *** review examines natural photosynthetic pathways,including retinal/rhodopsin-,bacteriochlorophyll-,and chlorophyll-based systems,highlighting their key components and ***,we outline reaction pathways in artificial photosynthetic systems constructed via heterogeneous,homogeneous,self-assembly,and semi-artificial strategies,focusing on water splitting,carbon fixation,and nitrogen ***,we offer insights into future directions for artificial photosynthesis,emphasizing the importance of using self-assembly strategies and the potential of using primitive phototrophic microorganisms as models.

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