Design of a Metasurface Antenna Based on Characteristic Mode Theory

A novel metasurface antenna consisting of 5×5 rectangular patch elements is presented.Thestructure with and without the central element are both analyzed by the Characteristic Mode Theory(CMT).The developed mutually orthogonal principal modes of the optimized periodic patch structure areexcited by a center-feed dipole.A differential feeding network is employed to realize impedance matching.Prototype with profile height of 0.07λ_(0)(λ_(0)is the wavelength in free space at the lowest operatingfrequency)is fabricated and assembled to verify the simulation results.The measured results show that thereflectance coefficient of proposed matesurface antenna is less than-10 dB in the whole operating bandrange from 4.2 GHz to 5.5 GHz,a relative bandwidth of 26.8%is achieved,and the maximummeasured realized gain is more than 9 dBi with a maximum radiation efficiency of 90%.The designprovides a guideline on the application of characteristic modes(CMs)to radiation problems.

Characteristic-based finite volume scheme for 1D Euler equations

In this paper, a high-order finite-volume scheme is presented for the one- dimensional scalar and inviscid Euler conservation laws. The Simpson＇s quadrature rule is used to achieve high-order accuracy in time. To get the point value of the Simpson＇s quadrature, the characteristic theory is used to obtain the positions of the grid points at each sub-time stage along the characteristic curves, and the third-order and fifth-order central weighted essentially non-oscillatory （CWENO） reconstruction is adopted to estimate the cell point values. Several standard one-dimensional examples are used to verify the high-order accuracy, convergence and capability of capturing shock.

The microwave scattering characteristics of sea ice in the Bohai Sea

Microwave remote sensing has become the primary means for sea-ice research, and has been supported by a great deal of field experiments and theoretical studies regarding sea-ice microwave scattering. However, these studies have been barely carried in the Bohai Sea. The sea-ice microwave scattering mechanism was first developed for the thin sea ice with slight roughness in the Bohai Sea in the winter of 2012, and included the backscattering coefficients which were measured on the different conditions of three bands（L, C and X）, two polarizations（HH and VV）, and incident angles of 20° to 60°, using a ground-based scatterometer and the synchronous physical parameters of the sea-ice temperature, density, thickness, salinity, and so on. The theoretical model of the sea-ice electromagnetic scattering is obtained based on these physical parameters. The research regarding the sea-ice microwave scattering mechanism is carried out through two means, which includes the comparison between the field microwave scattering data and the simulation results of the theoretical model, as well as the feature analysis of the four components of the sea-ice electromagnetic scattering. It is revealed that the sea-ice microwave scattering data and the theoretical simulation results vary in the same trend with the incident angles. Also, there is a visible variant in the sensitivity of every component to the different bands.For example, the C and X bands are sensitive to the top surface, the X band is sensitive to the scatterers, and the L and C bands are sensitive to the bottom surface, and so on. It is suggested that the features of the sea-ice surfaces and scatterers can be retrieved by the further research in the future. This experiment can provide an experimental and theoretical foundation for research regarding the sea-ice microwave scattering characteristics in the Bohai Sea.

Reconstruction of density and wave velocity from reflection and transmission data

Consider an inverse problem of reconstructing the coefficient in a linearwave equation on an inhomogeneous slab with density ρ(z) and wave velocity c(z). The inversioninput information is the reflection and transmission data corresponding to a point source. Byapplying the characteristic theory for hyperbolic equations, we establish an integral system fromwhich ρ(z) and c(z) can be recovered simultaneously. In contrast to some known results, our inverseapproach is carried out for depth variable, rather than for travel-time variable. Thereforeinversion results in this paper are more appropriate for the physical interpretation of a mediumslab.

My Way: A Computational Autobiography

In this paper,the author recounts his forty-year plus struggle to find a sound basis for understanding the computational fluid dynamics of compressible flow.

Asymptotic Behavior of Solutions for a Periodic Transport Equation with Delay

This paper analyzes a class of first order partial differential equations with delay (a model for the blood production system). The asymptotic behavior of solutions are studied.

Unified characteristics line theory of spacial axisymmetric plastic problem

The unified strength theory proposed by Yu in 1991 is extended to spacial axisymmetric problem. A unified spacial axismymmetric characteristics line theory based on the unified strength theory is proposed. This theory takes account of different effects of intermediate principal stress on yielding or failure and the SD effect (tensile-compression strength difference) of materials. Various conventional axisymmetric characteristics line theories, which are based on the Haar-von Karman plastic condition, Szczepinski hypothesis, Tresca criterion, von Mises criterion and Mohr-Coulomb theory, are special cases of the new theory. Besides, a series of new spacial axisymmetric characteristics fields for different materials can be introduced. It forms a unified spacial axisymmetric characteristics theory. Two examples are calculated with the new theory, the results are compared with those obtained by the finite element program UEPP and those based on the Mohr-Coulomb strength theory. It is shown that the new theory is reliable and feasible. The economic benefit can be obtained from the engineering application of the new theory.

Classification of Hardy Submodules and Characteristic Space Theory（A Brief and Selective Survey）

This paper is a brief and selective survey on classification of Hardy Submodules over the polydisk. The survey reports some progress in classification of Hardy submodules

The Theory of Composite and Switching Characteristics under Sampling Scheme-Ⅱ

3.Composite and Switching Characteristics under ISO 2859 Sampling Scheme IS(1)Graphs of sampling program of IS.

GAO Jian's Theoretical Thoughts in Translation

As an experienced translator and theorist, GAO Jian has translated numerous English works into Chinese and published a series of theoretical thoughts concerning the most fundamental problems in translation studies. He has formed a unique style in translation and proposed some theoretical concepts with great expertise. Gao represents the translators' spirit of the time. His theories are highly comprehensive and pragmatic. His discussion of translatability of style, relativity and the Language Characteristics Theory reflect the academic thinking among translators in China, which inspires many young translators and theorists.

The Gist of the Marxist view on Human Rights

Marx and engels’ great ideology contains rich thought on human rights. Based on the class structure and social development in their lifetimes, the two founders of Marxism profoundly revealed the essence of human rights. They revealed the historical process, class essence and hypocrisy of the bourgeois human rights, and expounded the important principle that human rights are always subject to economic and social development. The Marxist of human rights theory emphasizes that even in a capitalist society, the proletariat should not abandon its efforts to strive for human rights, and that the proletariat should use human rights well to improve their survival and development conditions as well as the advancement of the society as a whole. In the localization process of Marxism in China, the Marxist view on human rights has been further developed and innovated in China, and the socialist human rights theory with Chinese characteristics has been formed, which is used to guide the development of China’s human rights cause.

Lasry-Lions, Lax-Oleinik and generalized characteristics

In the recent works, an intrinsic approach of the propagation of singularities along the generalized characteristics was obtained, even in global case, by a procedure of sup-convolution with the kernel the fundamental solutions of the associated Hamilton-Jacobi equations. In the present paper, we exploit the relations among Lasry-Lions regularization, Lax-Oleinik operators(or inf/sup-convolution) and generalized characteristics, which are discussed in the context of the variational setting of Tonelli Hamiltonian dynamics, such as Mather theory and weak KAM(Kolmogorov-Arnold-Moser) theory.

Influence of the Radial Inertia Effect on the Propagation Law of Stress Waves in Thin-Walled Tubes

This investigation focused on the influence of the radial inertia effect on the propagation behavior of stress waves in thin-walled tubes subjected to combined longitudinal and torsional impact loads.Generalized characteristics theory was used to analyze the main features of the characteristic wave speeds and simple wave solutions in thin-walled tubes.The incremental elastic-plastic constitutive relations described by the rate-independent plasticity were adopted,and the finite difference method was used to investigate the evolution and propagation behaviors of combined elasticplastic stress waves in thin-walled tubes when the radial inertial effect was considered.The numerical results were compared with those obtained when the radial inertia effect was not considered.The results showed that the speed of the coupled stress wave increased when the radial inertia effect was considered.The hardening modulus of the material in the plastic stage had a greater impact on the coupled slow waves than on the coupled fast waves.

The Great Victory of Marxism in China

The birth in 1921 of the Communist Party of China （CPC） with Marxism as its guiding ideology was a major event that radically changed the historical fate of the Chinese people. In the 90 years since its founding the CPC has always persevered in combining Marxism with Chinese realities, constantly pushed forward theoretical innovations in the process of practical innovations and led the Chinese people in winning the great victory of socialism in China. These achievements represent a victory for the Chinese people in their historical choice, a victory for the CPC and a victory for Marxism in China. History has proved that only Marxism can save China and that the Sinicization of Marxism can be achieved only through constant theoretical innovations in this regard and, in the final analysis, through the Party＇s upholding of the ideological line of seeking truth from facts.