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Deflagration and detonation induced by shock wave focusing at different Mach numbers

Chinese Journal of Aeronautics 2024年第2期37卷 249-258页

作者： Zezhong YANG jun cheng Bo ZHANG School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

Shock wave focusing is an effective way to create a hot spot or a high-pressure and hightemperature region at a certain place,showing its unique usage in detonation initiation,which is beneficial for the development of detonation-based *** flame propagation behavior after the autoignition induced by shock wave focusing is crucial to the formation and self-sustaining of the detonation *** this study,wedge reflectors with two different angles(60°and 90°)and a planar reflector are employed,and the Mach number of incident shock waves ranging from 2.0 to 2.8 is utilized to trigger different flame propagation *** pressure transducers and the high-speed schlieren imaging system are both employed to investigate the shock-shock collision and ignition *** results reveal a total of four flame propagation modes:deflagration,DDT(Deflagration-to-Detonation Transition),unsteady detonation,and direct *** detonation wave formed in the DDT and unsteady detonation mode is only approximately 75%-85%of the Chapman-Jouguet(C-J)speed;meanwhile,the directly induced detonation wave speed is close to the C-J *** waves,which are strong evidence for the existence of detonation waves,are discovered in *** usage of wedge reflectors significantly reduces the initial pressure difference ratio needed for direct detonation *** also provide a practical method for differentiating between detonation and deflagration modes,which involves contrasting the speed of the reflected shock wave with the speed of the theoretically nonreactive reflected shock *** findings should serve as a reference for the detonation initiation technique in advanced detonation propulsion engines.

关键词： Deflagration Detonation Hydrogen Ignition Shock wave focusing

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Cohomology groups of a new class of Kadison-Singer algebras

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Science China Mathematics 2024年第3期67卷 593-606页

作者： Guangyu An Xing cheng jun Sheng School of Mathematics and Data Science Shaanxi University of Science and TechnologyXi’an 710021China

Let N be a maximal discrete nest on an infinite-dimensional separable Hilbert space H,ξ=∑^(∞)_(n=1)en/2. be a separating vector for the commutant N',E_(ξ)be the projection from H onto the subspace[Cξ]spanned by the vectorξ,and Q be the projection from K=H⊕H⊕H onto the closed subspace{(η,η,η)^(T):η∈H}.Suppose that L is the projection lattice generated by the projections(E_(ξ) 0 0 0 0 0 0 0 0),{(E 0 0 0 0 0 0 0 0):E∈N},(I 0 0 0 I 0 0 0 0) and *** show that L is a Kadison-Singer lattice with the trivial ***,we prove that every n-th bounded cohomology group H~n(AlgL,B(K))with coefficients in B(K)is trivial for n≥1.

关键词： Kadison-Singer algebra Kadison-Singer lattice derivation cohomology group

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Effects of the Rainfall-Triggered Lisse Effect on the Stability of Loess Slopes

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Journal of Earth Science 2024年第4期35卷 1254-1262页

作者： Zhizhou Yang Donghui cheng jun Xia School of Water and Environment Chang’an UniversityXi’an710054China Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education Chang’an UniversityXi’an710054China Key Laboratory of Eco-Hydrology and Water Security in Arid and Semi-Arid Regions of the Ministry of Water Resources Chang’an UniversityXi’an710054China Key Laboratory of Water Cycle&Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China State Key Laboratory of Water Resources&Hydropower Engineering Sciences Wuhan UniversityWuhan430000China

This paper coupled a water-air two-phase hydrodynamic(WATPH)model with the Iverson’s method to analyze the influence of the Lisse effect on the fast groundwater pressure(P_(w))response and the slope ***,the sensitivities of the driving force and loess soil parameters were *** showed that the WATPH model simulated the height and rise of the depth to the water table reasonably *** depth to water table before rainfall(H0)had a significant impact on the Lisse effect and the slope *** the H_(0) was less than approximately 1 m,the rainfall triggered a significant Lisse effect and decreased the slope factor of safety(F_(s)).When the rainfall intensity(R_(i))was higher than the saturated hydraulic conductivity(K_(s)),the Lisse effect and the F_(s) slightly changed with the increase of the R_(i),and the slope tended to be unstable with continuous *** increasing K_(s),the Lisse effect noticeably increased,and the minimum F_(s) quickly *** analysis of the normalized sensitivity coefficient revealed that H_(0) had a dramatic impact on the Lisse effect and loess slope *** different R_(i) and K_(s) values had prominent influences on the Lisse effect and slight impacts on F_(s).

关键词： Lisse effect landslides safety factor rainfall

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Continuous Orbit Equivalence of Semigroup Actions

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1581-1598页

作者： Xiang Qi QIANG cheng jun HOU School of Mathematical Science Yangzhou UniversityYangzhou 225002P.R.China

We introduce notions of continuous orbit equivalence and its one-sided version for countable left Ore semigroup actions on compact spaces by surjective local homeomorphisms,and characterize them in terms of the corresponding transformation groupoids and their operator *** particular,we show that two essentially free semigroup actions on totally disconnected compact spaces are continuously orbit equivalent if and only if there is a canonical abelian subalgebra preserving C^(∗)-isomorphism between the associated transformation groupoid C^(∗)-*** also give some examples of orbit equivalence,consider the special case of semigroup actions by homeomorphisms and relate continuous orbit equivalence of semigroup actions to that of the associated group actions.

关键词： Semigroup action continuous one-sided orbit equivalence continuous orbit equivalence groupoid C^(∗)-algebras

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A Fluorine-Functionalized 3D Covalent Organic Framework with Entangled 2. Layers

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Chinese Journal of Polymer Science 2024年第8期42卷 1210-1216页

作者： Li-Bang Xiao Zi-Han Wu jun-Jie Xin Yuan-Peng cheng Bo Gui jun-Liang Sun cheng Wang College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China College of Chemistry and Molecular Engineering Beijing National Laboratory for Molecular SciencesPeking UniversityBeijing 100871China

Constructing three dimensional(3D)covalent organic frameworks(COFs)through the entanglement of two dimensional(2.)nets is a promising but underdeveloped ***,we report the design and synthesis of a fluorine functionalized 3DCOF(3D-An-COF-F)formed by entangled 2. sql *** structure of 3D-An-COF-F was determined by the combination of continuous rotation electron diffraction technique and modelling based on the chemical information from real ***,compared to the isostructural 3D-An-COF without F atom s,3DAn-COF-F showed an improved CO_(2.sorption ability and higher CO_(2./N_(2.*** study not only demonstrated the generality of constructing 3D COFs with entangled 2. nets by introducing bulky groups vertically in planar building blocks,but also will expand the diversity of 3D COFs for various applications.

关键词： 3D covalent organic frameworks Fluorine Entangled 2. layers Electron diffraction CO_(2.adsorption

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Hybrid Beamforming Design and Signal Processing with Fully-Connected Architecture for mmWave Integrated Sensing and Communications

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Journal of Communications and Information Networks 2024年第2期9卷 151-161页

作者： Hongyu Li jun Gong Wenchi cheng The 54th Research Institute of China Electronics Technology Group Corporation Shijiazhuang 050080China State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710071China

Millimeter-wave (mmWave) is capable of achieving gigabit/second communication capacity and centimeter-level sensing accuracy and has become one of the main frequency bands for integrated sensing and communications (ISAC) research. Hybrid beamforming techniques have attracted much attention for solving the high path loss of mmWave and further reducing the hardware cost of the system. However, the related studies based on multicarrier and fully-connected hybrid architectures are still limited. For this reason,this paper investigates the orthogonal frequency division multiplexing (OFDM) based mmWave fully-connected hybrid architecture ISAC system to form a stable communication beam and dynamically varying sensing beam. In order to realize the aforementioned multifunctional beams, the hybrid beamformer design problem based on weighted error minimization of multicarrier is proposed and solved efficiently using the penalty dual decomposition (PDD) algorithm. Meanwhile, based on the echo model, the multicarrier multiple signal classification (MUSIC) algorithm for target angle of arrival estimation and the two-dimensional discrete Fourier transform(2.-DFT)algorithm for distance and velocity estimation are proposed, respectively. Numerical simulation results show that by adjusting the weighting factor,a flexible trade-off can be formed between the communication spectrum efficiency and the sensing accuracy error.

关键词： integrated sensing and communications hybrid beamforming fully-connected architecture millimeter-wave

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Remarkable Wear Resistance in a Complex Concentrated Alloy with Nanohierarchical Architecture and Composition Undulation

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Research 2024年第1期2023卷 403-416页

作者： Yushan Geng Wenyuan Chen Hui Tan jun cheng Shengyu Zhu jun Yang Weimin Liu State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000PR China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049PR China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000PR China

Sustained wear damages on the sliding surfaces of alloys are generally the culprit responsible for the failure of various mechanical *** by high-entropy effects,here we deliberately deploy nanohierarchical architecture with composition undulation in a Ni50(AlNbTiV)_(50) complex concentrated alloy,which yields ultralow wear rate within the order of 10^(−7) to 10^(−6) mm^(3)/Nm between room temperature and 800℃.Such remarkable wear resistance heretofore represents one of the highest wear resistance reported for the bulk alloys or composites,and originates from the multi-type adaptive friction interface protection governed by intrinsically nano-coupled grains and *** cooperative heterostructure releases gradient frictional stress in stages upon wear at room temperature through the coexistence of multiple deformation pathways while activating a dense nanocrystalline glaze layer upon wear at 800℃ to minimize adhesive and oxidative *** work uncovers a practical avenue for tailoring wear properties with multicomponent heterostructures over a wide temperature range.

关键词： wear alloys friction

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Progress and prospects of chiral nanomaterials for biosensing platforms

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Rare Metals 2024年第6期43卷 2469-2497页

作者： Yu-cheng Ouyang Bong-jun Yeom Yuan Zhao Wei Ma School of Food Science and Technology State Key Laboratory of Food Science and ResourcesJiangnan UniversityWuxi 214122China Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnanUniversityWuxi214122China Department of Chemical Engineering Hanyang UniversitySeoul04763RepublicofKorea

Chiral nanomaterials have distinct chiroptical properties of preferential interactions to circularly polarized ***-based biosensors have emerged for detection of biomolecules,ions and cells in recent *** review provides an extensive overview of biosensors based on chiral nanomaterials,starting with approaches to chiral nanomaterials construction in terms of fabrication *** of chiral nanomaterials and their biosensor applications is presented for different material types,with special emphasis on the role and importance of material properties and signal generation in *** assessed the technological prospects of the emerging fields of chiral construction,circularly polarized luminescence,Raman optical activity and so on along with their current *** venues for future research on chiral nanomaterials in fabrication,biosensing,disease diagnosis and treatment are also presented in the review.

关键词： Chiral nanomaterials Circular dichroism Biosensors

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In situ anchoring in carbon matrix of Bi_(2.O_(2.CO_(3) as a high-performance anode material for Li-ion batteries

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Rare Metals 2024年第8期43卷 3634-3646页

作者： Pu-Qiang He jun Guo Hui Huang Zhong-cheng Guo Faculty of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China Research Center of Metallurgical Electrode Materials Engineering Technology Kunming 650106China Kunming Hendera Science and Technology Co. Ltd.Kunming 650106China

Bismuth-based anode materials have been regarded as promising Li-ion batteries due to their high theoretical ***,their low conductivity and associated volume expansion inhabited their *** this work,Bi_(2.O_(2.CO_(3)@C composites were successfully synthesized by in situ anchoring of flower-like Bi_(2.O_(2.CO_(3) nanosheets on a carbon-based substrate via *** unique composited structure of Bi_2._(2.-CO_(3)@C leads to a stable specific capacity of 547 mAh·g^(-1)after 100 cycles at a current density of 0.1 A·g^(-1).Notably,it demonstrates excellent rate capability with a specific capacity of 2.0 mAh·g^(-1)at 5 A·g^(-1).After 550 cycles at a current density of 0.5 A·g^(-1),a high reversible capacity of nearly 400 mAh·g^(-1)was ***,in situ X-ray diffraction measurements clearly demonstrate the conversion between Bi and Li_(3)Bi during alloying/dealloying,confirming the good electrochemical reversibility of the materials for Li *** reaction kinetics of Bi_(2.O_(2.CO_(3)@C were further investigated using galvanostatic intermittent titration ***,Bi_2._(2.-CO_(3)@C exhibited excellent long-term stability,maintaining its high reversible capacity for over 2.0 cycles at a current density of 0.5 A·g^(-1)in a full cell configuration using Li_(1.2.)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2. as the cathode *** result further underscores its promising potential for lithium-ion *** work may provide inspiration for the design of alloy-type negative electrode materials for high-performance rechargeable batteries.

关键词： Bi_(2.O_(2.CO_(3) Composite materials Anode materials Full batteries

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Transferable adversarial slow feature extraction network for few-shot quality prediction in coal-to-ethylene glycol process

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Chinese Journal of Chemical Engineering 2024年第7期71卷 258-271页

作者： cheng Yang Chao Jiang Guo Yu jun Li Cuimei Bo School of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816China Department of Intelligent Manufacturing Nanjing Tech UniversityNanjing 210009China

In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory analysis to obtain these variables,which often incurs substantial monetary costs and significant time *** resulting few-shot learning scenarios present a hurdle to the efficient development of predictive *** address this issue,our study introduces the transferable adversarial slow feature extraction network(TASF-Net),an innovative approach designed specifically for few-shot quality prediction in the CTEG ***-Net uniquely integrates the slowness principle with a deep Bayesian framework,effectively capturing the nonlinear and inertial characteristics of the CTEG ***,the model employs a variable attention mechanism to identify quality-related input variables adaptively at each time step.A key strength of TASF-Net lies in its ability to navigate the complex measurement noise,outliers,and system interference typical in CTEG *** learning strategy using a min-max game is adopted to improve its robustness and ability to model irregular industrial data accurately and ***,an incremental refining transfer learning framework is designed to further improve few-shot prediction performance achieved by transferring knowledge from the pretrained model on the source domain to the target *** effectiveness and superiority of TASF-Net have been empirically validated using a real-world CTEG *** with some state-of-the-art methods,TASF-Net demonstrates exceptional capability in addressing the intricate challenges for few-shot quality prediction in the CTEG process.

关键词： Chemical process Neural networks Slowness principle Transfer learning Prediction

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