Frequency-Diversified Space-Efficient Radiating Surface Using Convolved Electric and Magnetic Currents for Highly Dense Multiband Antenna-Frontend Integration

We propose and investigate a methodology based on convolved electric and magnetic currents for the generation of multi-band responses over a space-shared radiating surface.First,a single wideband antenna operation principle based on inter-leaved dipole and slot modes is studied and analyzed using full-wave simulations followed by a qualitative time domain analysis.Subsequently,a 2×2 dual-band radiating unit is conceived and developed by closely arranging single wideband antennas.In this case,multimode resonances are generated in a lower frequency band by a proper convolving and coupling of the magnetic and electric currents realized in the gaps between the antennas and on the surface of the antennas,respectively.This methodology can be deployed repeatedly to build up a self-scalable topology by reusing the electromagnetically(EM)connected radiating surfaces and gaps be-tween the radiating units.Due to the efficient reuse of the electromagnetic region for the development of multiband radiation,a high aperture-reuse efficiency is achieved.Finally,as a proof of concept,a 2×4 dual-band array operating in Ku-and Ka-bands is devel-oped and fabricated by a linear arrangement of the two developed radiating units.Our measurement results show that the proposed antenna array provides impedance and gain bandwidths of 30%and 25.4%in the Ku-band and 10.65%and 8.52%in the Ka-band,respectively.

Developments and Prospects of Long-Span High-Speed Railway Bridge Technologies in China

With the rapid developments of the high-speed railway in China, a great number of long-span bridges have been constructed in order to cross rivers and gorges. At present, the longest main span of a constructed high-speed railway bridge is only 630 m. The main span of Hutong Yangtze River Bridge and of Wufengshan Yangtze River Bridge, which are under construction, will be much longer, at 1092 m each. In order to overcome the technical issues that originate from the extremely large dead loading and the relatively small structural stiffness of long-span high-speed railway bridges, many new technologies in bridge construction, design, materials, and so forth have been developed. This paper carefully reviews progress in the construction technologies of multi-function combined bridges in China, including com- bined highway and railway bridges and multi-track railway bridges. Innovations and practices regarding new types of bridge and composite bridge structures, such as bridges with three cable planes and three main trusses, inclined main trusses, slab-truss composite sections, and steel-concrete composite sections, are introduced. In addition, investigations into high-performance materials and integral fabrication and erection techniques for long-span railway bridges are summarized. At the end of the paper, prospects for the future development of long-span high-speed railwav bridges are provided.

Protecting Important Agricultural Heritage Systems(IAHS)by Industrial Integration Development(IID):Practices from China

With Globally Important Agricultural Heritage Systems(GIAHS)increasing in number around the world,their conservation has become a new international research theme.From the perspective of combining theoretical analyses and practical case applications,this study examines the Important Agricultural Heritage Systems(IAHS)conservation pathways and operation mechanisms through industrial integration development(IID).First,the theoretical framework of IID in IAHS sites was constructed according to the requirements of IAHS conservation,which include analyses of the connotation and basic principles of IID,the necessity of IID for IAHS sites,the resource conditions,and the IID pathways.And then based on the theoretical framework,the IID of Longji Terraces in Guangxi,Honghe Hani Rice Terraces System in Yunnan(HHRTS),Aohan Dryland Farming System in Inner Mongolia(ADFS),and Huzhou Mulberry-dyke&Fish-pond System(HMFS)in Zhejiang are analyzed systematically.The main finding is that IID is an effective pathway for IAHS conservation.However,the IID in IAHS sites must stress the ecological and cultural values of the resources;IID should be based on local resource advantages;and IID should attach importance to the combination of different policies and coordination between different stakeholders.

HIGH-ORDER SYMPLECTIC AND SYMMETRIC COMPOSITION METHODS FOR MULTI-FREQUENCY AND MULTI-DIMENSIONAL OSCILLATORY HAMILTONIAN SYSTEMS

The multi-frequency and multi-dimensional adapted Runge-Kutta^NystrSm （ARKN） integrators, and multi-frequency and multi-dimensional extended Runge-Kutta-NystrSm （ERKN） integrators have been developed to efficiently solve multi-frequency oscillatory Hamiltonian systems. The aim of this paper is to analyze and derive high-order sym- plectic and symmetric composition methods based on the ARKN integrators and ERKN integrators. We first consider the symplecticity conditions for the multi-frequency and multi-dimensional ARKN integrators. We then analyze the symplecticity of the adjoint in- tegrators of the multi-frequency and multi^dimensional symplectic ARKN integrators and ERKN integrators, respectively. On the basis of the theoretical analysis and by using the idea of composition methods, we derive and propose four new high-order symplectic and symmetric methods for the multi-frequency oscillatory Hamiltonian systems. The numer- ical results accompanied in this paper quantitatively show the advantage and efficiency of the proposed high-order symplectic and symmetric methods.

Engineering applications and technical challenges of active array microsystems

In the post-Moore era,the development of active phased array antennas will inevitably trend towards active array microsystems.In this paper,the characteristics and composition of the active array antenna are briefly described.Owing to the high efficiency,low profile,and light weight of the active array microsystems,the application prospects and advantages in the engineering of multi-functional airborne radar,spaceborne radar,and communication systems are analyzed.Moreover,according to the characteristics of the post-Moore era of integrated circuits,scientific and technological problems in the active array microsystems are presented,including multi-scale,multi-signal,and multi-physics field coupling.The challenges are also discussed,such as new architectures and algorithms,miniaturization of passive components,novel materials and processes,ultra-wideband technology,and new interdisciplinary technological applications.This paper is expected to inspire in-depth research on active array microsystems.

A Reliability Model for Integrated Energy System Considering Multi-energy Correlation

An integrated energy system (IES) is a regional energy system incorporating distributed multi-energy systems to serve various energy demands such as electricity, heating, cooling, and gas. The reliability analysis plays a key role in guaranteeing the safety and adequacy of an IES. This paper aims to build a capacity reliability model of an IES. The multi-energy correlation in the IES can generate the dependent capacity outage states, which is the distinguished reliability feature of an IES from a generation system. To address this issue, this paper presents a novel analytical method to model the dependent multi-energy capacity outage states and their joint outage probabilities of an IES for its reliability assessment. To model the dependent multi-energy capacity outage states, a new multi-dimensional matrix method is presented in the capacity outage probability table (COPT) model of the generation system. Furthermore, a customized multi-dimensional discrete convolution algorithm is proposed to compute the reliability model, and the adequacy indices are calculated in an accurate and efficient way. Case studies demonstrate the correctness and efficiency of the proposed method. The capacity value of multi-energy conversion facilities is also quantified by the proposed method.

On the rate of convergence of the Legendre spectral collocation method for multidimensional nonlinear Volterra-Fredholm integral equations

While the approximate solutions of one-dimensional nonlinear Volterra-Fredholm integral equations with smooth kermels are now well understood,no systematic studies of the numerical solutions of their multi-dimensional counterparts exist.In this paper,we provide an efficient numerical approach for the multi-dimensional nonlinear Volterra-Fredholm integral equations based on the multi-variate Legendre-collocation approach.Spectral collocation methods for multi-dimensional nonlinear integral equations are known to cause major difficulties from a convergence analysis point of view.Consequently,rigorous error estimates are provided in the weighted Sobolev space showing the exponential decay of the numerical errors.The existence and uniqueness of the numerical solution are established.Numerical experiments are provided to support the theoretical convergence analysis.The results indicate that our spectral collocation method is more flexible with better accuracy than the existing ones.

Fiber-shaped Supercapacitors:Advanced Strategies toward High-performances and Multi-functions

Fiber-shaped supercapacitors(FSSCs)show great potential in portable and wearable electronics due to their unique advantages of high safety,environmental friendliness,high performances,outstanding flexibility and integrability.They can directly act as the power sources or be easily integrated with other flexible devices to constitute self-powered and sustainable energy suppliers,providing excellent adaptability to irregular surfaces.This review mainly summarizes the recently reported works of FSSCs including preparation methods of various fiber electrodes,construction strategies of FSSCs and multi-functional device integrations,exploration of reaction mechanisms and strategies to improve the electrochemical performance and provision of suggestions on further designing and optimization of FSSCs.Meanwhile,it shares our perspectives on challenges and opportunities in this field,shedding light on the development of high-performance fiber-shaped supercapacitors with multifunctions.

Statistical Identification of Syndromes Feature and Structure of Disease of Western Medicine Based on General Latent Structure Model

Syndrome differentiation is the character of Chinese medicine （CM）. Disease differentiation is the principle of Western medicine （WM）. Identifying basic syndromes feature and structure of disease of WM is an important avenue for prevention and treatment of integrated Chinese and Western medicine. The idea here is first to divide all patients suffering from a disease of WM into several groups in the light of the stage of the disease, and secondly to identify basic syndromes feature in a distinct stage, and finally to achieve the purpose of syndrome differentiation. Syndrome differentiation is simply taken as a classifier that classifies patients into distinct classes primarily based on overall observation of their symptoms. Previous clustering methods are unable to cope with the complexity of CM. We therefore show a new multi-dimensional clustering method in the form of general latent structure （GLS） model, which is a suitable statistical learning technique of latent class analysis. In this paper, we learn an optimal GLS model which reflects much better model quality compared with other latent class models from the osteoporosis patient of community women （OPCW） real data including 40 65 year old women whose bone mineral density （BMD） is less than mean2.0 standard deviation （M 2.0SD）. Further, we illustrate a case analysis of statistical identification of CM syndromes feature and structure of OPCW from qualitative and quantitative contents through the GLS model. Our analysis has discovered natural clusters and structures that correspond well to CM basic syndrome and factors of osteoporosis patients （OP）. The GLS model suggests the possibility of establishing objective and quantitative diagnosis standards for syndrome differentiation on OPCW. Hence, for the future it can provide a reference for the similar study from the perspective of a combination of disease differentiation and syndrome differentiation.

Conservation laws of some lattice equations

We derive infinitely many conservation laws for some multi- dimensionally consistent lattice equations from their Lax pairs. These lattice equations are the Nijhoff-Quispel-Capel equation, lattice Boussinesq equation, lattice nonlinear SchrSdinger equation, modified lattice Boussinesq equation, Hietarinta＇s Boussinesq-type equations, Schwarzian lattice Boussinesq equation, and Toda-modified lattice Boussinesq equation.