Low profile equilateral-triangular dielectric resonator antenna ofvery high permittivity

An aperture-coupled equilateral-triangular dielectric resonator antenna (DRA) of very high permittivity (ϵ_r=82) is investigated experimentally. The triangular DRA is more compact in size than rectangular and circular disk DRAs operating at the same frequency. The impedance matching, radiation patterns and antenna gain of the triangular DRA are presented     

Numerical investigations of the dynamic processes in vibroimpact systems in modeling impacts by a force of contact interaction

On the basis of the results of numerical analysis, it is shown that the introduction of a force of contact interaction varying according to the Hertz law to the equation of motion makes it possible to model impacts between colliding bodies both under harmonic and stochastic external loads. This enables us to deduce the law of motion of the bodies in a vibroimpact system for the entire time axis, including the period of impact. We perform the numerical optimization of the parameters of the vibroimpact system by the method of gradient projection with correction of the discrepancy in constraints. The comparative analysis of the efficiency of the dynamic nonimpact dampers and shock absorbers of vibrations is presented. Translated from Problemy Prochnosti, No. 6, pp. 82–90, November–December, 2008.     

Small circularly polarised folded patch antenna

A small circularly polarised (CP) patch antenna with dual T-shaped probe feeds is presented. The patch is folded like a cap to generate a CP wave as well as to reduce the size of the antenna. The proposed antenna is operated at the centre frequency of 2.28 GHz with circular polarisation. The impedance bandwidth (SWR<2) is 21.8% from 2 to 2.49 GHz and the axial ratio bandwidth (AR<3 dB) is 3.5%. The measured gain is around 7.5 dBi. The antenna shows a good CP performance with a symmetric radiation pattern. The total area of reduction is 54% in comparison with the conventional half-wave patch antenna.     

High-gain and wide-band single-layer patch antenna for wireless communications

A technique employing the use of parallel feeds is applied to the recently proposed L-probe coupled patch antenna design. By employing only two L-probes, with proper separation, for feeding one single patch, a twin-L-probe coupled patch antenna is designed with both high-gain (10 dBi) and wide-band [25%, standing wave radio (SWR) /spl les/ 1.5] characteristics. In addition, the 1-dB-gain bandwidth is around 26%, which covers the impedance bandwidth. Furthermore, a noticeable suppression of cross-polarization radiation is observed. Simulation results are in good agreement with those noteworthy characteristics obtained from experiments. The proposed antenna is suitable for modern mobile communication applications.     

FARMTASIA: an online game-based learning environment based on the VISOLE pedagogy

Virtual interactive student-oriented learning environment (VISOLE) is a game-based constructivist pedagogical approach that encompasses the creation of an online interactive world modeled upon a set of interdisciplinary domains, in which students participate as “citizens” to take part cooperatively and competitively in shaping the development of the virtual world as a means to construct their knowledge and skills. FARMTASIA is the first online game designed using the VISOLE philosophy, encompassing the subject areas of biology, government, economics, technology, production system and natural environment. The “virtual world” deployed is a farming system covering the domains of cultivation, horticulture and pasturage, situated in a competitive economy governed by good public policies. The design and implementation of FARMTASIA pursue three vital principles. The first one is to make the game as realistic as possible so that students can learn in a near-real life environment; the second one is to inject motivational elements so that students can sustain to learn and acquire various knowledge and skills with the game; and the third one is to make easy for teachers to conduct various VISOLE facilitation tasks. According to our exploratory educational study, we show evidentially that positive perceptions and an advancement of subject-specific and interdisciplinary knowledge appeared among the students who participated in VISOLE learning with FARMTASIA.     

一种新型毫米波磁电偶极子天线阵列设计

该文将磁电偶极子天线作为辐射阵子,并应用一种共面波导馈电网络,研究并设计了一种新型44毫米波天线阵列。这种设计不仅具有很宽的阻抗带宽和增益带宽,而且价格低廉易于生产。仿真和测试结果表明,此天线阵列的相对阻抗带宽为54.5%, 3 dB增益带宽为37.1%,在工作频带内(40.2~70.0 GHz),最大增益为18.1 dBi。而基于其他技术设计的44毫米波天线阵列(如微带天线、偶极子天线)工作频带宽度一般在20%左右,增益一般在16~17 dBi。所以该文提出的天线阵列设计具有明显的优势。另外,仿真设计结果和实测的电参数数据有较好的一致性。     

An Evaluation Model for the Coordinated Development of a Circular Economy in China and Its Application to Energy-intensive Industries

Energy-intensive industries (EIIs) are fundamental to the industrial development of China and are also the key industries of a circular economic infrastructure. It is worth paying attention to the coordinated development of a circular economy using EIIs due to the present interrelationship among EIIs. It is related to the optimization and comprehensive performance improvement of a circular economy. Based on the perspective of order parameter, this study uses economic and environmental subsystems to establish an evaluation model that examines the coordinated development of a circular economy within six main EIIs and an EII cluster from 2006 to 2011 in China. The result shows that the level of coordinated development in a circular economy among six EIIs differs and the level of coordinated development of circular economy among the EII cluster lags behind that of each EII examined. It also shows that the outside coordinated degree of EIIs is lower than the inside coordinated degree of each EII.     

Incorporating temporal information into level set functional for robust ventricular boundary detection from echocardiographic image sequence

Echocardiographic images often suffer from dropouts that lead to loss of signals on the ventricular boundary and cause the level set curve used to detect the boundary leaking out from the gaps on the boundary. In this paper, a novel method that incorporates temporal information into the level set functional is proposed to solve the leakage problem encountered when detecting the heart wall boundary from the echocardiographic image sequence. The ventricular boundary is quantitatively partitioned and classified into strong and weak segments. The weak segments are considered to be weakened by dropouts and there is low confidence on the presence of boundary. Temporal information from neighboring frames is exploited as a regularizer into the level set equation. Hence, the original boundary information in the weak segments can be reconstructed and the curve leakage problem can be remedied. Experimental results demonstrate the advantages of the proposed method for the intended task.     

PbO<Subscript>2</Subscript>-TiO<Subscript>2</Subscript> composite electrodes

Electrodeposition of composite PbO₂-based materials containing titanium dioxide particles was studied. The TiO₂ content of the composite depends on the bath composition and the deposition conditions. Inclusion of TiO₂ particles in PbO₂ substantially changes the morphology and structure of the deposit. The oxygen overpotential at composite materials increased but the rate of the conversion of 4-chlorophenol into nontoxic compounds remained virtually unchanged. The lifetime of the electrodes containing the inert TiO₂ phase was found to be twice as long as that of traditional PbO₂ anodes.     

Locating straight-line edge segments on outdoor scenes

Straight-line edge segments are often used as key features in building scene models. This paper presents techniques for extracting edge segments from a digital picture. First, an edge detection is performed on the entire picture to obtain a list of edge elements. Second, these edge elements are parametrically transformed. Third, using this parametric representation, the edge elements are divided into several groups. Each group consists of edge elements which lie on a contiguous portion of a straight line. The line segments extracted are represented by the positions of their two end points. Results of line extraction on a few outdoor scenes are also presented.