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Analysis of Time-domain Electromagnetic Scattering Problem by Multiple cavities

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Acta Mathematicae Applicatae Sinica 2020年第1期36卷 18-48页

作者： Yang LIU Yi-xian GAO Jian ZU School of Mathematics and Statistics and Center for Mathematics and Interdisciplinary SciencesNortheast Normal UniversityChangchunJilin 130024China

The time-domain multiple cavity scattering problem,which arises in diverse scientific areas,has significant industrial and military *** multiple cavities,embedded in an infinite ground plane,is filled with inhomogeneous media characterized by variable dielectric permittivities and magnetic *** to the transverse electric,the scattering problem can be studied by the Helmholtz equation in frequency domain and wave equation in time-domain respectively.A novel transparent boundary condition in time-domain is developed to reformulate the cavity scattering problem into an initial-boundary value problem in a bounded *** well-posedness and stability of the reduced problem are ***,a priori energy estimates for the electric field is obtained with minimum regularity requirement for the data and an explicit dependence on the time by studying the wave equation directly.

关键词： Helmholtz equation wave equation multiple cavities stability a priori estimates

6-8 Volume Production of HWR010 cavities in IMP

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IMP & HIRFL Annual Report 2015年第1期 269-270页

作者： Yue Weiming Zhang Shenghu He Yuan Linac Group 不详

The development of the Half Wave Resonator (HWR010) is based on the China ADS project. The HWR010 operates at 162.5 MHz and can provide more than 0.78 MV of accelerating voltage per cavity for proton with opt=0.10. The goal of the RF properties is to get a lower heat load and a higher accelerating gradient, which are determined by a higher R/Q0 and lower peak surface fields (Bpk/Eacc and Epk/Eacc). In order to optimize the HWR geometry parameters, CST-MWS is used to conduct the RF simulation. The optimized RF parameters are show in Table 1.

关键词： HWR010 cavities IMP

From histology to micro-CT:Measuring and modeling resorption cavities and their relation to bone competence

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World Journal of Radiology 2014年第9期6卷 643-656页

作者： Jef Vanderoost G Harry van Lenthe Department of Mechanical Engineering KU Leuven3001 Leu-venBelgium

The process of bone remodelling plays an essential role in the emergence and maintenance of bone geometry and its internal *** are one of the three main bone cell types that play a crucial role in the bone remodelling *** the microstructural level,osteoclasts create bone deficits by eroding resorption *** how these cavities impair the mechanical quality of the bone is not only relevant in quantifying the impact of resorption cavities in healthy bone and normal aging,but maybe even more so in quantifying their role in metabolic bone ***-bolic bone diseases and their treatment are both known to affect the bone remodelling cycle;hence,the bone mechanical competence can and will be ***-ever,the current knowledge of the precise dimensions of these cavities and their effect on bone competence is rather *** is not surprising considering the difficulties in deriving three-dimensional(3D)properties from two-dimensional(2D)histological *** measurement difficulties are reflected in the evalua-tion of how resorption cavities affect bone *** detailed 3D models are generally being used to quantify the mechanical impact of the cavities,the representation of the cavities themselves has basicallybeen limited to simplified shapes and averaged ***,these models indicate that cav-ity size and location are important,and that the effectof cavities is larger than can be expected from simplebone *** summary,the dimensions of osteoclastresorption cavities were until recently estimated from2D measures;hence,a careful interpretation of resorp-tion cavity dimensions is *** effort needsto go into correctly quantifying resorption cavities usingmodern 3D imaging techniques like micro-computedtomography(micro-CT)and synchrotron radiation *** resorption cavities affect bone *** structure-function relationships have been ana-lysed using computat

关键词： Resorption cavities Histology Micro-com-puted tomography

Comparative Analysis of the Lateritic Soil of Brasília and Soil Mixed with Vermiculite for Urban cavities

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Journal of Civil Engineering and Architecture 2020年第7期14卷 385-390页

作者： Neusa Maria Bezerra Mota Sonny Albert Amorim da Silva Bruno de Castro Biill Faculty of Applied Social Sciences and Technology University Center of BrasíliaBrasília 70790-075Brazil

Civil construction has high demand for new procedures and technologies capable of generating better results in numerous situations throughout the ***,cavities in urban areas are commonly used due to the implantation of commercial and residential developments with more than two floors,seeking a better use of the nobler areas of the big *** geotechnical terms,the filling of these cavities,with the local soil,especially in the Federal District,lateritic soils,can represent additional efforts for the structures and foundations and lead to a compromise of the technical and functional performance of the same,compromising the efficiency and the economy of the *** this sense,this research evaluates the mechanical behavior of the mixtures,using GEO5 Software,Containment Design and Verification Modules,presenting an alternative to fill cavities in urban regions,with a mixture of material with lower specific density in relation to the soil *** Normal compression tests,simple direct shear saturation and sample expansibility were *** results showed a reduction of 38%in the strength of the reinforced concrete curtain,as well as a 25%reduction in maximum bending moments and 31%in maximum shear forces,and a reduction of about 32%in the displacements of the structure to the soil with addition of expanded vermiculite for tests obtained in the saturated *** the compositions of cement soil,expanded vermiculite soil and soil cement and expanded vermiculite,the deformations were of the order of 0.3%,0.4%and 0.2%,respectively.

关键词： Soil mixed with vermiculite reconstitution of cavities reduction of specific density

Improvement of Mechanical Properties of Wood-Plastic Composite Floors Based on the Optimum Structural Design

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Acta Mechanica Solida Sinica 2016年第4期29卷 444-454页

作者： Yang Zhang Ping Xue Yun Ding Mingyin Jia Jianchen Cai Xiaoming Jin College of Mechanical and Electrical Engineering Beijing University of Chemical Technology College of Mechanical Engineering Quzhou University

A study is carried out on the structural design of wood-plastic composite floors. The geometric parameters of the cavities, the structure, and the means to optimize the performance of these light boards are investigated. Various structural parameters of the boards, such as size, shape, and the pattern of cavities are also studied. The optimal structure can be determined by calculation and analysis of the strength, stiffness, weight and cost of the material. A finite element model for the mechanical analysis of wood-plastic composite floors is established; and the results are used to verify the strength criteria under bending deformation, which is the most common loading condition of flooring board.

关键词： wood plastic composite cavities flooring board optimal structure the finite element model

Limited Effect of Twin Boundaries on Radiation Damage

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Acta Metallurgica Sinica(English Letters) 2016年第1期29卷 72-78页

作者： Jin Gao Zhi-Jun Liu Fa-Rong Wan Department of Materials Physics and Chemistry School of Materials Science and EngineeringUniversity of Science and Technology Beijing

The different influences of the general grain boundary and the twin boundary on the cavity formation were investigated in copper irradiated by helium at room temperature. Large number of the cavities with sizes smaller than 5 nm formed after irradiation, which were almost homogenously distributed inside the grains. However, the distribution of the cavities varied near the general grain boundary and the twin boundary. cavities-depleted zone was readily observed near the general grain boundaries, which was rarely observed near the twin boundaries. Meanwhile, decoration of dense cavities within the grain boundary plane was observed. The results suggested the limited influence of the twin boundaries as the point defect sinks compared with the general grain boundaries.

关键词： Transmission electron microscopy cavities cavities-depleted zone General grainboundary Twin boundary

Effects of A Top SiO2 Surface Layer on Cavity Formation and Helium Desorption in Silicon

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Journal of Rare Earths 2006年第Z1期24卷 78-82页

作者： Liu Changlong Yin Lijun Lü Yiying Alquier D Department of Physics School of Science Tianjin University Tianjin 300072 China Tianjin Key Laboratory of Low Dimension Materials Physics and Preparing Technology Institute of Advanced Materials Physics Faculty of Science Tianjin 300072 China Department of Physics School of Science Tianjin University Tianjin 300072 China Department of Physics School of Science Tianjin University Tianjin 300072 China LMP/STMicroelectronics 16 rue Pierre et Marie Curie B. P. 7155 F37071 Tours Cedex France

Cz n-type Si (100) samples with and without a top SiO2 layer were implanted with 40 keV helium ions at the same dose of 5×1016 cm-2. Cross-sectional transmission electron microscopy (XTEM) and thermal desorption spectroscopy (THDS) were used to study the thermal evolution of cavities upon and helium thermal release, respectively. XTEM results show that the presence of the top SiO2 layer could suppress the thermal growth of cavities mainly formed in the region close to the SiO2/Si interface, which leads to the reduction in both the cavity band and cavity density. THDS results reveal that the top oxide layer could act as an effective barrier for the migration of helium atoms to the surface, and it thus gives rise to the formation of more overpresurrized bubbles and to the occurrence of a third release peak located at about 1100 K. The results were qualitively discussed by considering the role of the oxide surface layer in defect migration and evolution upon annealing.

关键词： silicon SiO2 layer helium implantation cavities helium release

Dipole and generalized oscillator strength derived electronic properties of an endohedral hydrogen atom embedded in a Debye-Huckel plasma

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Matter and Radiation at Extremes 2018年第5期3卷 227-242页

作者： C.Martínez-Flores R.Cabrera-Trujillo Instituto de Ciencias Físicas Universidad Nacional Autonoma de MexicoAp.Postal 43-8CuernavacaMorelos62251Mexico

We report electronic properties of a hydrogen atom encaged by an endohedral cavity under the influence of a weak plasma interaction. Weimplement a finite-difference approach to solve the Schrodinger equation for a hydrogen atom embedded in an endohedral cavity modeled by theWoods-Saxon potential with well depth V0, inner radius R0, thickness D, and smooth parameter g. The plasma interaction is described by aDebye-Hu¨ckel screening potential that characterizes the plasma in terms of a Debye screening length lD. The electronic properties of theendohedral hydrogen atom are reported for selected endohedral cavity well depths, V0, and screening lengths, lD, that emulate differentconfinement and plasma conditions. We find that for low screening lengths, the endohedral cavity potential dominates over the plasma interaction by confining the electron within the cavity. For large screening lengths, a competition between both interactions is observed. We assessand report the photo-ionization cross section, dipole polarizability, mean excitation energy, and electronic stopping cross section as function of lD and V0. We find a decrease of the Generalized Oscillator Strength (GOS) when the final excitation is to an s state as the plasma screeninglength decreases. For a final excitation into a p state, we find an increase in the GOS as the endohedral cavity well-depth increases. For the caseof the electronic stopping cross section, we find that the plasma screening and endohedral cavity effects are larger in the low-to-intermediateprojectile energies for all potential well depths considered. Our results agree well to available theoretical and experimental data and are afirst step towards the understanding of dipole and generalized oscillator strength dependent properties of an atom in extreme conditions encagedby an endohedral cavity immersed in a plasma medium.

关键词： Oscillator strengths Debye-Huckel plasma cavities Endohedral Energy loss Stopping power

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What limits limits?

National Science Review 2021年第1期8卷 11-14页

作者： Yong-Chun Liu Kun Huang Yun-Feng Xiao Lan Yang Cheng-Wei Qiu State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Frontier Science Center for Quantum Information Tsinghua University Department of Optics and Optical Engineering University of Science and Technology of China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of Physics Peking University Department of Electrical and Systems Engineering Washington University Department of Electrical and Computer Engineering National University of Singapore

There are fundamental rules and principles setting the limits of physical systems. It triggers an interesting thought—can we break the limits under specific circumstances? A realistic system can only provide limited functionalities because its performance is physically constrained by some fundamental principles.‘Breaking the limit’, which usually implies that the capability of a system could be enhanced significantly,

关键词： cavities