Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 7

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Abstract: Currently, one of the challenging tasks for Chinese engineering community is to construct a water-way crossing of Qiongzhou Strait in the south of China. This project has also gained significant attention from researchers in academia. The study presented herein is centered on providing a feasible solution for ac-complishing the above mentioned task. Initially, different alternatives as the best location, judged on the basis of the environmental constraints, are studied. Then the comparison between various structural solutions such as suspension bridge, submarine tunnel and SFT is presented. Among these solutions, SFT appears to be a very suitable alternative for Qiongzhou Strait waterway crossing due to distinctive advantages, like shorter distance, lower cost, less impact on environment and navigation, etc. Based on the appropriate conception for cross sections, support systems, materials, joints and connection schemes, a numerical model is developed by means of the FEM software ANSYS/Fluent. It is then analyzed under the influence of different environmental loading conditions, varying the wave heights and lengths, current velocities and water depths, which are typical in Qiongzhou Strait. The numerical results reveal that the proposed SFT solution performs safely even under extreme weather conditions.
EN
Jarosite residues, which are generated in a zinc production plant by a hydrometallurgical process, contain a large amount of valuable metal components. In this study, a method was proposed for the recovery of lead, zinc and iron from the residues and simultaneous sulfur fixation through direct reduction followed by magnetic separation. The influences of the roasting temperature, roasting time and the concentration of SO2 gas in the direct reduction process were researched in detail. Results showed that the volatilization rates of lead, zinc and sulfur were 96.97%, 99.89% and 1.09%, respectively, and the iron metallization rate was 91.97% under optimal reduction conditions; roasting temperature 1523 K for 60 min. The magnetic concentrate with the iron content of 90.59% and recovery rate of 50.87% was obtained from the optimal reduction product by grinding and magnetic separation. The optimum fineness for separation 96.56% less than 37 μm accounted with magnetic field strength 24 kA/m. The theoretical analysis was carried out by thermodynamics, X-ray powder diffraction, gas analysis and scanning electron microscopy.
EN
Personal identification is particularly important in information security. There are numerous advantages of using electroencephalogram (EEG) signals for personal identification, such as uniqueness and anti-deceptiveness. Currently, many researchers focus on single-dataset personal identification, instead of the cross-dataset. In this paper, we propose a method for cross-dataset personal identification based on a brain network of EEG signals. First, brain functional networks are constructed from the phase synchronization values between EEG channels. Then, some attributes of the brain networks including the degree of a node, the clustering coefficient and global efficiency are computed to form a new feature vector. Lastly, we utilize linear discriminant analysis (LDA) to classify the extracted features for personal identification. The performance of the method is quantitatively evaluated on four datasets involving different cognitive tasks: (i) a four-class motor imagery task dataset in BCI Competition IV (2008), (ii) a two-class motor imagery dataset in the BNCI Horizon 2020 project, (iii) a neuromarketing dataset recorded by our laboratory, (iv) a fatigue driving dataset recorded by our laboratory. Empirical results of this paper show that the average identification accuracy of each data set was higher than 0.95 and the best one achieved was 0.99, indicating a promising application in personal identification.
EN
This paper develops a new actuator failure compensation scheme for two linked two-wheel drive (2WD) mobile robots based on multiple-model control. First, a configuration of two linked 2WD robots is described, and their kinematics and dynamics are modeled. Then, a multiple-model based failure compensation scheme is developed to compensate for actuator failures, consisting of a kinematic controller, multiple dynamic controllers and a control switching mechanism, which ensures system stability and asymptotic tracking properties. Finally, simulation results verify the effectiveness of the proposed failure compensation control system.
EN
This paper focuses on supervisory fault tolerant control design for a class of systems with faults ranging over a finite cover. The proposed framework is based on a switched system approach, and relies on a supervisory switching within a family of pre-computed candidate controllers without individual fault detection and isolation schemes. Each fault set can be accommodated either by one candidate controller or by a set of controllers under an appropriate switching law. Two aircraft examples are included to illustrate the efficiency of the proposed method.
EN
Based on a Takagi-Sugeno (T-S) fuzzy model and an inverse system method, this paper deals with the problem of actuator fault estimation for a class of nonlinear dynamic systems. Two different estimation strategies are developed. Firstly, T-S fuzzy models are used to describe nonlinear dynamic systems with an actuator fault. Then, a robust sliding mode observer is designed based on a T-S fuzzy model, and an inverse system method is used to estimate the actuator fault. Next, the second fault estimation strategy is developed. Compared with some existing techniques, such as adaptive and sliding mode methods, the one presented in this paper is easier to be implemented in practice. Finally, two numerical examples are given to demonstrate the efficiency of the proposed techniques.
7
Content available remote Potential Jurassic/Cretaceous boundary in northeastern China
EN
On the basis of the geological ranges of the Buchia and dinoflagellate cyst assemblages and their global correlation, two distinct biostratigraphical boundaries (event horizons) can be distinguished in the continu ous deposits spanning the Jurassic/Cretaceous boundary in the Dong'anzhen Formation of Dong'an, Raohe County and the Dongrong Formation of boreholes SB86-11 and SB79-1 of Suibin, Suibin County of eastern Heilongjiang, northeasteren China (Fig. 1.). Level 1. The base of the Buchia fischeriana - Buchia unschensis assemblage is characterized by the occurrence of Buchia (e.g. B. unschensis) with inversoid ontogenetic growth of the right valve, and the absence of the underlying B. russiensis, one of the index species of the Buchia russiensis - Buchia fischeriana assemblage, with obliquoid ontogenetic growth of the right valve (Fig. 1, column 2b). The top of the dinoflagellate cyst Amphorula delicate assemblage underlies, but it is near this boundary (Fig. 1, column 2a). This level basically corresponds to the currently accepted Tethyan version of the Jurassic/Cretaceous boundary and the working base of the Cretaceous as recommended by the International Commission on Stratigraphy (www.stratigraphy.org) (Fig. 1, column 1), and approximately corresponds to the boundary between the Boreal Middle-Upper Volgian substages (Fig. 1, column 3). This is because the base of the Buchia unschensis Zone or the base of the Buchia fischeriana - Buchia unschensis assemblage nearly coincides with that of the Boreal Craspedites exoticus Subzone or Craspedites okensis ammonite Zone, which in turn correspond closely to the base of Tethyan Lower Berriasian Berriasella jacobi ammonite Zone (Fig. 1, column 1), which is the index ammonite zone of the Tethyan or the international chronostratigraphic base of Berriasian, and thus the base of the Cretaceous (Fig. 1, column 1). Level 2. The base of the Buchia volgensis - Buchia cf. subokensis - Buchia cf. okensis - Buchia unschensis assemblage, is characterized by those easy-to-recognize large-sized Buchia with inversoid ontogenetic growth of the right valve and even of the left valve, and absence of Buchia fischeriana (Fig. 1, column 2b). The base of the Oligosphaeridium pulcherrimum dinoflagellate cyst assemblage probably corresponds approximately to the base of this Buchia assemblage (Fig. 1, column 2a). This level is very near the Boreal version of the Jurassic/Cretaceous boundary, which corresponds approximately to the base of the Tethyan middle part of Middle Berriasian. This is because the bases of both Buchia volgensis and Buchia cf. okensis in the assemblage of Buchia volgensis - Buchia cf. subokensis - Buchia cf. okensis - Buchia unschensis are closely coincident with the base of the upper Lower Berriasian Boreal Hectoroceras kochi Zone (Fig. 1, columns 2b, 3), and the Tethyan upper Berriasella privasensis Subzone of the Tirnovella occitanica Zone of the middle part Middle Berriasian, approximately corresponds to the middle of the Boreal Lower Berriasian Substage (Fig. 1, columns 1, 3).
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.