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Structural performance of flexible freeform panelssubjected to wind loads

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 851-869页

作者： yong YOO Zaryab SHAHID Renzhe chen Maria KOLIOU Anastasia MULIANA Negar KALANTAR Zachry Department of Civil and Environmental Engineering Texas A&M UniversityCollege StationTX 77843USA J.Mike Walker'66 Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA Architecture Division California College of the ArtsSan FranciscoCA 94107USA

An increased number of hurricanes and tornadoes have been recorded worldwide in the last decade,while research efforts to reduce wind-related damage to structures become *** architecture,which focuses on generating complex curved shapes including streamlined shapes,has recently gained *** study focuses on investigating the potential of kerf panels,which have unique flexibility depending on the cut patterns and densities,to generate complex shapes for facades and their performance under wind *** investigate the kerf panel's potential capacity against wind loads,static and dynamic analyses were conducted for two kerf panel types with different cut densities and pre-deformed *** was observed that although solid panels result in smaller displacement amplitudes,stresses,and strains in some cases,the kerf panels allow for global and local cell deformations resulting in stress reduction in various locations with the potential to reduce damage due to overstress in *** the predeformed kerf panels,it was observed that both the overall stress and strain responses in kerf cut arrangements were lower than those of the flat-shaped *** study shows the promise of the use of kerf panels in achieving both design flexibility and performance demands when exposed to service *** that this newly proposed architectural configuration(design paradigm)for facades could revolutionize structural engineering by pushing complex freeform shapes to a standard practice that intertwines aesthetic arguments,building performance requirements,and material design considerations has the potential for significant practical applications.

关键词： freeform structure kerfing method wind load analysis cladding component

Operando investigation of particle re-entrainment mechanism in electrostatic capture process on the lab-on-a-chip

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Journal of Environmental Sciences 2024年第2期136卷 337-347页

作者： yong Zhu Yikun Zhang Xiaoyong Yang Shanlong Tao Mingxia chen Wenfeng Shangguan Research Center for Combustion and Environmental Technology School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Inhalable particle is a harmful air pollutant that causes a significant threat to people's health and ecological environments,which should be removed to purify air,but there exists limited removal efficiency due to particle ***,Operando observation system based on microscopic visualization method is developed to make in situ test of particle migration,deposition and re-entrainment characteristics on a lab-on-a-chip to achieve the investigation in micro-level *** deposition evolution of charged particles is recorded in electric field region intuitively,which confirms the fracture of particle chain occurs during the growth process of deposited *** captures the instantaneous process that a larger particle with micron size due to the coagulation of submicron particles fractures from main body of the particle chain for the first *** analysis of migration behavior of a single submicron particle near electrode surface demonstrates the direct influence of drag force on the fracture of particle *** work is the first-time visualization of dynamic process and mechanism elucidation of particle re-entrainment at the micron level,and the findings will provide the theory support for the particle re-entrainment mechanism and bring inspires of enhancing capture efficiency of inhalable particle.

关键词： Inhalable particle Re-entrainment mechanism Operando observation Lab-on-a-chip Capture efficiency

Large-disturbance Stability Analysis of Power Systems with Synchronous Generator and Converter-interfaced Generation

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 997-1002页

作者： Lei chen yong Min Liangshuai Hao Guangzheng Xing Yalou Li Shiyun Xu Department of Electrical Engineering Tsinghua UniversityBeijing 100084China China Electric Power Research Institute Beijing 100192China

This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite *** power system is multi-timescale and first *** is shown that the boundary of region of attraction(ROA)of the simplified model is composed of stable manifolds of unstable equilibrium point(UEP)or semi-singular point(SSP),named anchor points,and singular surface *** type of anchor point determines the dominant instability pattern of the power *** the anchor point is UEP or SSP,the dominant instability pattern is the instability of rotor angle of SG or the instability of phase-locked loop and outer control loop(OCL)of CIG,*** of dominant instability pattern can be analyzed with the relative position relationship between UEP and *** effect of OCL is *** the OCL is activated,the ROA becomes smaller and the system is more prone to instability of *** is necessary to consider the OCL when studying the large-disturbance stability of the power system.

关键词： Converter-interfaced generation large-disturbance stability outer control loop phase-locked loop synchronous generator voltage source converter

The Weighted Basis for PHT-Splines

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工程与科学中的计算机建模(英文) 2024年第1期138卷 739-760页

作者： Zhiguo yong Hongmei Kang Falai chen School of Mathematical Sciences Soochow UniversitySuzhou215006China School of Mathematical Sciences University of Science and Technology of ChinaHefei230026China

PHT-splines are defined as polynomial splines over hierarchical T-meshes with very efficient local refinement *** original PHT-spline basis functions constructed by the truncation mechanism have a decay phenomenon,resulting in numerical *** non-decay basis functions are constructed as the B-splines that are defined on the 2×2 tensor product meshes associated with basis vertices in Kang et al.,but at the cost of losing the partition of *** the field of finite element analysis and topology optimization,forming the partition of unity is the default ingredient for constructing basis functions of approximate *** this paper,we will show that the non-decay PHT-spline basis functions proposed by Kang et *** be appropriately modified to form a partition of *** non-decay basis function is multiplied by a positive weight to form the weighted *** weights are solved such that the sum of weighted bases is equal to 1 on the *** provide two methods for calculatingweights,based on geometric information of basis functions and the subdivision of *** are given in the form of explicit formulas and can be efficiently *** also prove that the weights on the admissible hierarchical T-meshes are positive.

关键词： PHT-splines partition of unity weighted bases PHT-splines subdivision

Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

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Petroleum Science 2024年第4期21卷 2638-2649页

作者： chen-Xing Fan Deng Li yong Kang Hai-Tao Zhang Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University School of Power and Mechanical Engineering Wuhan University

Unsubmerged cavitating abrasive waterjet(UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally,the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 μm with a roughness of 127 μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

Geometric prior guided hybrid deep neural network for facial beauty analysis

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CAAI Transactions on Intelligence Technology 2024年第2期9卷 467-480页

作者： Tianhao Peng Mu Li Fangmei chen yong Xu David Zhang The School of Computer Science and Technology Guizhou UniversityGuiyangChina Department of Automation Moutai InstituteRenhuaiGuizhouChina The School of Computer Science and Technology Harbin Institute of TechnologyShenzhenShenzhenChina The Information and Communication Engineering Department Dalian Minzu UniversityDalianChina The School of Data Science The Chinese University of Hong KongShenzhenShenzhenChina

Facial beauty analysis is an important topic in human *** may be used as a guidance for face beautification applications such as cosmetic *** neural networks(DNNs)have recently been adopted for facial beauty analysis and have achieved remarkable ***,most existing DNN-based models regard facial beauty analysis as a normal classification *** ignore important prior knowledge in traditional machine learning models which illustrate the significant contribution of the geometric features in facial beauty *** be specific,landmarks of the whole face and facial organs are introduced to extract geometric features to make the *** by this,we introduce a novel dual-branch network for facial beauty analysis:one branch takes the Swin Transformer as the backbone to model the full face and global patterns,and another branch focuses on the masked facial organs with the residual network to model the local patterns of certain facial ***,the designed multi-scale feature fusion module can further facilitate our network to learn complementary semantic information between the two *** model optimisation,we propose a hybrid loss function,where especially geometric regulation is introduced by regressing the facial landmarks and it can force the extracted features to convey facial geometric *** performed on the SCUT-FBP5500 dataset and the SCUT-FBP dataset demonstrate that our model outperforms the state-of-the-art convolutional neural networks models,which proves the effectiveness of the proposed geometric regularisation and dual-branch structure with the hybrid *** the best of our knowledge,this is the first study to introduce a Vision Transformer into the facial beauty analysis task.

关键词： deep neural networks face analysis face biometrics image analysis

Enhancement of Ising superconductivity in monolayer NbSe_(2) via surface fluorination

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Science China(Technological Sciences) 2024年第7期67卷 2099-2106页

作者： WU JiZheng SHI WuJun WANG Chong Duan WenHui XU yong SI chen School of Materials Science and Engineering Beihang UniversityBeijing 100191China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE) ShanghaiTech UniversityShanghai 201210China State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijing 100084China Frontier Science Center for Quantum Information Beijing 100084China

Recently discovered Ising superconductors have garnered considerable interest due to their anomalously large in-plane upper critical fields(B_(c2)). However, the requisite strong spin-orbital coupling in the Ising pairing mechanism generally renders these superconductors heavy-element dominant with notably low superconducting transition temperatures(Tc). Here, based on the Migdal-Eliashberg theory and the mean-field Bogoliubov-de Gennes Hamiltonian, we demonstrate a significant enhancement of Ising superconductivity in monolayer NbSe_(2) through surface fluorination, as evidenced by concomitant improvements in Tcand Bc_(2). This enhancement arises from three predominant factors. Firstly, fluorine atoms symmetrically and stably adhere to both sides of the monolayer NbSe_(2), thereby maintaining the out-of-plane mirror symmetry and locking carrier spins ***, fluorination suppresses the charge density wave in monolayer NbSe_(2) and induces a van Hove singularity in the vicinity of the Fermi level, leading to a marked increase in the number of carriers and, consequently, strengthening the electron-phonon coupling(EPC). Lastly, the appearance of fluorine-related, low-frequency phonon modes further augments the EPC. Our findings suggest a promising avenue to elevate Tcin two-dimensional Ising superconductors without compromising their Ising pairing.

关键词： Ising superconductivity surface functionalization upper critical field NbSe_(2) first-principles calculations

Exciting broadband thermochromic transmission property opposite to vanadium dioxide in the atmospheric window

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Science China(Technological Sciences) 2024年第7期67卷 2244-2254页

作者： GONG YiQuan GUO YanMing chen ShuNi LI Meng PAN QingHui SHUAI yong Ministry of Industry and Information Technology Key Laboratory of Aerospace Thermophysics School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

The traditional telecommunications band performs poorly in harsh weather conditions due to atmospheric absorption. In recent years, researchers have begun to study optical communication through atmospheric windows, and optical switches are an essential component of optical communication. A broadband atmospheric window optical switch was proposed based on Vanadium dioxide and magnetic polaritons(MP). It is formed by the stacking of two metal-dielectric-metal structures. The simulation results show that the modulation depth can reach 98.38%, and the extinction ratio is 17.93 dB. By calculating the magnetic field, we confirmed that the reason for the “off” mode is the coupling between the different MP modes, while the “on”mode is the excitation of MP. The optical switch we proposed may be applied to radiation cooling and optical satellite communication.

关键词： optical communication thermochromic property atmospheric window optical switch magnetic polariton

A continuous and long-term in-situ stress measuring method based on fiber optic. Part I: Theory of inverse differential strain analysis

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Petroleum Science 2024年第2期21卷 1171-1189页

作者： Kun-Peng Zhang Mian chen Chang-Jun Zhao Su Wang yong-Dong Fan State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China MOE Key Laboratory of Petroleum Engineering in China University of Petroleum Beijing102249China Beijing International Center for Gas Hydrate School of Earth and Space SciencesPeking UniversityBeijing100871China

A method for in-situ stress measurement via fiber optics was proposed. The method utilizes the relationship between rock mass elastic parameters and in-situ stress. The approach offers the advantage of long-term stress measurements with high spatial resolution and frequency, significantly enhancing the ability to measure in-situ stress. The sensing casing, spirally wrapped with fiber optic, is cemented into the formation to establish a formation sensing nerve. Injecting fluid into the casing generates strain disturbance, establishing the relationship between rock mass properties and treatment ***, an optimization algorithm is established to invert the elastic parameters of formation via fiber optic strains. In the first part of this paper series, we established the theoretical basis for the inverse differential strain analysis method for in-situ stress measurement, which was subsequently verified using an analytical model. This paper is the fundamental basis for the inverse differential strain analysis method.

关键词： In-situ stress Fiber optic Orthotropic elastic Differential evolution ABAQUS