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Numerical study on hydrodynamic characteristics of spherical bubble contaminated by surfactants under higher Reynolds numbers

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Chinese Journal of Chemical Engineering 2022年第5期35卷 268-283页

作者： Tao Sun Mingjun pang Yang Fei School of Mechanical Engineering and Rail Transit Changzhou UniversityChangzhou 213164China

It is of significance to investigate deeply the hydrodynamic featu res of the bubble co ntaminated by impurities in view of the fact that the industrial liquid is difficult to keep absolutely *** the basis of the finite volume method,the bubble interface contaminated by the surfactant(1-pentanol)is achieved through solving the concentration transport equations in liquid and along the bubble interface,and solving the absorption and desorption equation at the bubble *** the three-dimensional momentum equation is solved at the same *** is investigated in detail on the influence of interfacial contamination degrees(described with the cap angleθ)on hydrodynamic characteristics of the spherical bubble when the bubble Reynolds number(Re)is larger than ***θis realized by changing the surfactant concentration(C_(0)) in *** present results show that the hydrodynamic characteristics,such as interfacial concentration,interfacial shear stress,interfacial velocity and wake flow,are related to both Re and C_(0) for the contaminated *** C_(0) is relatively low in liquid(i.e.,the contamination degree of the bubble interface is relatively slight),the hydrodynamic characteristics of the bubble can still keep the 2 D features even if Re>*** decrease ofθor the increase of Re can promote the appearance of the unsteady wake *** the present investigation,when Re>200 andθ≤60°,the hydrodynamic characteristics of the bubble show the 3D phenomena,which indicates that axisymmetric model is no longer valid.

关键词： Bubble higher Reynolds number Interfacial parameters Wake flow Adsorption Desorption

Optimal planning for a multi-debris active removal mission with a partial debris capture strategy

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Chinese Journal of Aeronautics 2023年第6期36卷 256-265页

作者： Jia GUO Zhaojun pang Zhonghua DU School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

In this paper,a new mission model,called a multi-debris active removal mission with partial debris capture strategy,is *** model assumes that a platform only captures part of the scheduled debris at a time and then releases these debris pieces to a disposal *** process is then repeated until all of the scheduled debris is removed.A genetic algorithm with a multiparameter concatenated coding method is designed to optimize the plan of a multi-debris active removal mission with a partial debris capture strategy.A set of six pieces of debris and a set of 10 pieces of debris are selected to demonstrate the proposed planning *** result confirms the effectiveness of the genetic algorithm with the multi-parameter concatenated coding *** new mission model provides a more comprehensive decision-making framework than the existing mission models and makes it possible to further decrease mission costs.

关键词： Debris capture strategy Genetic algorithm Multi-debris active removal Space debris

Empirical Likelihood Inference for the Semiparametric Varying-Coefficient Spatial Autoregressive Model

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Journal of Systems Science & Complexity 2021年第6期34卷 2310-2333页

作者： LUO Guowang WU Mixia pang Zhen College of Big Data Statistics Guizhou University of Finance and EconomicsGuiyang 550025China College of Statistics and Data Science Faculty of ScienceBeijing University of TechnologyBeijing 100124China Department of Applied Mathematics Hong Kong Polytechnic UniversityHong KongChina

In this paper empirical likelihood(EL)-based inference for a semiparametric varyingcoefficient spatial autoregressive model is *** maximum EL estimators for the parametric component and the nonparametric component are ***,asymptotic properties of the proposed estimators and EL ratios are derived,and the corresponding confidence regions/bands are *** finite sample performances are studied via simulation and an example.

关键词： Confidence regions empirical likelihood instrumental variable residual-adjusted Wilks theorem

Theoretical uncertainties of(d,^(3)he)and(^(3)he,d)reactions owing to the uncertainties of optical model potentials

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Nuclear Science and Techniques 2023年第6期34卷 147-153页

作者： Wei-Jia Kong Dan-Yang pang School of Physics Beihang UniversityBeijing100191China School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang UniversityBeijing100191China

The theoretical uncertainties of single proton transfer cross sections of the(^(3)he,d)and(d,^(3)he)reactions,owing to the uncertainties of the entrance-and exit-channel optical model potentials,are examined with the^(30)Si(^(3)he,d)^(31)P,^(13)B(d,^(3)he)^(12)Be,and^(34)S(^(3)he,d)^(35)Cl reactions at incident energies of 25,46,and 25 MeV,respectively,within the framework of the distorted wave Born *** differential cross sections at the first peaks in the angular distributions of these reactions are found to have uncertainties of approximately 5%,owing to the uncertainties in the optical model potentials from 20,000 calculations of randomly sampled *** amount of uncertainty is found to be nearly independent of the angular momentum transfer and the target masses within the studied range of incident *** in the single proton spectroscopic factors obtained by matching the theoretical and experimental cross sections at different scattering angles are also discussed.

关键词： Proton transfer reactions Optical model potentials Spectroscopic factors

Additive manufacturing of energetic materials:Tailoring energetic performance via printing

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Journal of Materials Science & Technology 2022年第32期127卷 29-47页

作者： Nihan Chen Chunlin he Siping pang Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China Yangtze Delta Region Academy of Beijing Institute of Technology Jiaxing 314019China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 401120China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

Additive manufacturing(AM),also called three-dimensional(3D)printing,has been developed to obtain energetic materials within the past decade.3D printing represents a family of flexible manufacturing techniques that enable fast and accurate fabrication of structures with complex 3D features and a broad range of sizes,from submicrometer to several *** methods have already been explored,including templating,melting extrusion,inkjet printing and electrospray *** was demonstrated that the structure achieved by AM could be used to manipulate the reactivity of energetic or reactive materials by changing the flow of gases and entrained particles via *** employing different AM techniques,energetic materials with controllable nanostructures and uniformly dispersed ingredients can be *** is exciting to tailor the energy release without defaulting to change the formulation of the conventional *** combustion and mechanical properties of conventional energetic materials can be retained at the same *** this review,the preparation and characterization of AM energetic materials that have been developed in the last decade are *** AM techniques used in the fabrication of energetic materials are compared and *** particular,formulations of energetic materials applied in AM,metallic fuels,binders and energetic fillers and their advantages in terms of combustion efficiency and other properties are proposed.

关键词： Additive manufacturing Energetic materials Nanothermite Propellant

Thin Film of Mesoporous MCM-41 Grown on Indium-Tin-Oxide Glass Substrate

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Chinese Chemical Letters 1999年第4期10卷 335-338页

作者： Zhang, J Xiong, hM Ding, h Cai, Q Chen, JS pang, WQ Jilin Univ Key Lab Inorgan Synthesis & Preparat Chem Changchun 130023 Peoples R China Jilin Univ Dept Chem Changchun 130023 Peoples R China Chongqing Teachers Coll Dept Chem Yongchuan 402168 Peoples R China

From a basic solution containing celyltrimethylammonium cations as the template, thin film of mesoporous MCM-41 has been grown on the surface of a pre-treated indium-tin-oxide conducting glass substrate. The channel axis of the film is oriented parallel with the surface plane of the substrate, and the film is stable after careful removal of template in vacuum.

关键词： mesoporous MCM-41 film ITO glass substrate basic medium synthesis

Application of Coordinate-Momentum Intermediate Representation in Solving Eigenstate Problem of a Coupled Oscillator System

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Communications in Theoretical Physics 2005年第3X期44卷 440-444页

作者： pang Qian-Jun Department of Physics Shanghai Jiao Tong University Shanghai 200030 China

We study the eigenstate problem of a kind of coupled oscillators in the new quantum mechanical representation ｜q,μ,υ〉, which is defined as the eigenvector of the operator （μQ ＋ υP）, whereμ and υ are two real parameters. We also use the U operator transformation method to deal with the same problem. We obtain the normally ordered product expressions of U operator and eigenvector. It is shown that the ground state of system hamiltonian is a squeezed state.

关键词： coordinator-momentum intermediate representation coupled oscillator operator transformation method

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

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Nano-Micro Letters 2020年第4期12卷 152-167页

作者： Gaihua he Yuping Duan huifang pang Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) School of Materials Science and Engineering Dalian University of Technology

Crystalline Fe/MnO@C core–shell nanocapsules inlaid in porous amorphous carbon matrix(FMCA)was synthesized successfully with a novel confinement *** heterogeneous Fe/MnO nanocrystals are with approximate single-domain size which gives rise to natural resonance in 2–18 *** addition of MnO2 confines degree of graphitization catalyzed by iron and contributes to the formation of amorphous *** heterogeneous materials composed of crystalline–amorphous structures disperse evenly and its density is significantly reduced on account of porous ***,adjustable dielectric loss is achieved by interrupting Fe core aggregation and stacking graphene conductive *** dielectric loss synergistically with magnetic loss endows the FMCA enhanced *** optimal reflection loss(RL)is up to−45 dB,and the effective bandwidth(RLhz with 2.0 mm *** proposed confinement strategy not only lays the foundation for designing high-performance microwave absorber,but also offers a general duty synthesis method for heterogeneous crystalline–amorphous composites with tunable composition in other fields.

关键词： Crystalline nanocapsule Amorphous carbon Core–shell structure Interfacial polarization Microwave absorption

Negative corrections to black hole entropy from string theory

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 71-76页

作者： Liang Ma Yi pang hong Lu Center for Joint Quantum Studies and Department of Physics School of ScienceTianjin UniversityTianjin 300350China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China

We report for the first time that in heterotic string compactified on 4-torus or equivalently IIA string compactified on K3,the leading α′corrections to the rotating black string entropy at fixed conserved charges can be *** further implies that the correction to the mass of extremal rotating string is positive,opposite to the standard expectation from the weak gravity *** result suggests that the validity of positivity of entropy shift due to higher order operators depends on other factors omitted previously in the effective field theory analysis.

关键词： supergravities higher-derivative corrections effective theories black holes quantum gravity string theory