Xie C.,Huazhong University of Science and Technology |
Chen B.,Huazhong University of Science and Technology |
Wu J.,Wenhua College
Micromachines | Year: 2017
The interaction of dielectrophoresis (DEP) particles in an electric field has been observed in many experiments, known as the "particle chains phenomenon". However, the study in 3D models (spherical particles) is rarely reported due to its complexity and significant computational cost. In this paper, we employed the iterative dipole moment (IDM) method to study the 3D interaction of a large number of dense DEP particles randomly distributed on a plane perpendicular to a uniform alternating current (AC) electric field in a bounded or unbounded space. The numerical results indicated that the particles cannot move out of the initial plane. The similar particles (either all positive or all negative DEP particles) always repelled each other, and did not form a chain. The dissimilar particles (a mixture of positive and negative DEP particles) always attracted each other, and formed particle chains consisting of alternately arranged positive and negative DEP particles. The particle chain patterns can be randomly multitudinous depending on the initial particle distribution, the electric properties of particles/fluid, the particle sizes and the number of particles. It is also found that the particle chain patterns can be effectively manipulated via tuning the frequency of the AC field and an almost uniform distribution of particles in a bounded plane chip can be achieved when all of the particles are similar, which may have potential applications in the particle manipulation of microfluidics. © 2017 by the authors.
Jiang H.,Huazhong University of Science and Technology |
Han T.,Huazhong University of Science and Technology |
Ge X.,Huazhong University of Science and Technology |
Wang L.,Wenhua College
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST | Year: 2017
With the development of the 5G communication systems, the coexistence of a variety of wireless networks has become an inevitable trend. Different wireless networks have different features and applications. However, they are independent of each other and have no cooperative relationship in the most of cases. This paper investigates the application of the Software Defined Network (SDN) and wireless network function vitalization on the access control criterion of the heterogeneous cellular networks. The SDN controller manages all wireless access points based on the inaccurate feedback network state information. Wireless network virtualization technology can simplify the complexity of the system running and improve the efficiency of the communication system based on the utility theory which takes a number of respects into consideration, such as the maximum achievable data rate, signal-to-interference-and-noise ratio (SINR) and the traffic load state. Moreover, a discrete stochastic optimization algorithm is presented to solve the problem of inaccurate feedback information in a fast convergence rate, which is caused by the delay and noise over wireless channels. Extensive simulations show that our proposed model and algorithm can achieve utility optimization considering practical parameters configurations in wireless networks. © ICST Institute forComputer Sciences, Social Informatics andTelecommunicationsEngineering 2017.
Zhong Z.,Huazhong University of Science and Technology |
Wang X.,Wenhua College |
Zhang J.,Huazhong University of Science and Technology |
Zhong H.,Beijing Institute of Technology |
Han J.-B.,Huazhong University of Science and Technology
Applied Physics Letters | Year: 2017
An optical method for detecting magnetic fields is developed based on the photoluminescence (PL) properties of a Mn4+:K2SiF6 phosphor. Under excitation by a 457-nm argon laser, strong red PL was observed in Mn4+:K2SiF6 microcrystals from room to liquid helium temperatures. The Lande factor (g) of the Zeeman splitting peaks remained close to 2 within the measured temperature range. These features make this Mn4+:K2SiF6 phosphor an idea optical material for remote sensing of high magnetic fields over a broad temperature range. © 2017 Author(s).
Liu H.,Wenhua College |
He X.,Wenhua College |
Guo P.,Wenhua College
AIP Conference Proceedings | Year: 2017
Three factors (pouring temperature, injection speed and mold temperature) were selected to do three levels L9 (33)orthogonal experiment, then simulate processing of semi-solid die-casting of magnesium matrix composite by Flow-3D software. The stress distribution, temperature field and defect distribution of filling process were analyzed to find the optimized processing parameter with the help of orthogonal experiment. The results showed that semi-solid has some advantages of well-proportioned stress and temperature field, less defect concentrated in the surface. The results of simulation were the same as the experimental results. © 2017 Author(s).
Xu X.Y.,Wenhua College |
Wang K.,China Classification Society Wuhan Branch
Advanced Materials Research | Year: 2014
A design layout optimization for deformable trimaran with the basis of DTMB5415 based on BP neural network is presented. With taking CFD software calculated results for its sample values, BP neural network can predict resistances of the unit displacement under different layout and speed through trained. From above, the best layout of the ship adjusted with the speed can be drawn on the basis of ensuring the calculation accuracy. Compared to traditional CFD method, BP neural network can not only greatly reduce the computational time but also search for the optimal layout corresponding to any speed quickly and reliably. CFD method limited the layout and speed to obtain the minimum resistance value, and BP neural network method broke this inherent mode above and it really play the “deformable” advantage. It can be better applied to engineering practice and provides a new idea for computer-aided layout optimization of triamran. © (2014) Trans Tech Publications, Switzerland.
Yu Y.,Huazhong University of Science and Technology |
Fan S.-S.,Huazhong University of Science and Technology |
Dai H.-W.,Huazhong University of Science and Technology |
Ma Z.-W.,Huazhong University of Science and Technology |
And 3 more authors.
Applied Physics Letters | Year: 2014
The third-order optical nonlinearity and response time of Au nanobipyramids have been investigated by using optical Kerr effect technique. Large third-order nonlinear optical susceptibility (χ(3)) and ultrafast optical response time have been obtained at the longitudinal surface plasmon resonance (LSPR) wavelength. As the excitation laser wavelength varies from non-resonance wavelength of 780 nm to the LSPR wavelength of 825 nm, χ(3) increases from 7.4 × 10-14 to 3.9 × 10-13 esu, the fast component of the response time decreases from 141 ± 23 to 83 ± 8 fs and the ratio of the fast component remains around 48%, while the slow response time decreases from 3200 ± 200 to 2310 ± 158 fs. The large enhancement of χ(3) is due to the large local field enhancement caused by the surface plasmon resonance, and the shortening of the response times are induced by the increased probability of the electron-electron and electron-phonon scatterings in the nanosystem. This significant ultrafast optical property in Au nanobipyramids has great application in future ultrafast information processors. © 2014 AIP Publishing LLC.
Zhu H.,Wenhua College |
Hu L.,Huazhong University of Science and Technology
Measurement: Journal of the International Measurement Confederation | Year: 2016
In the displacement measurement using digital speckle correlation method, significant measuring error due to the multi-peak nature of the correlation coefficient function is a critical issue as sometimes the secondary peak can be wrongly determined as the maximum instead of the highest peak. In the multi-frequency harmonic wave correlation method (MHCM) as proposed in this work, for speckle patterns before and after the displacement, correlation calculations were performed on corresponding sets of data matrices assembled by amplitudes/intensities obtained from harmonic waves with different frequencies. The calculated maximum correlation coefficients were compared with each other to locate the maximum in order to measure the displacement. Both ultrasonic speckle MHCM and laser speckle MHCM were applied to the displacement measurement respectively. Measured results indicated that MHCM effectively helps to ensure the correct determination of the maximum correlation coefficient, to avoid random errors caused by other factors and improves the measurement accuracy in the meanwhile. © 2016 Elsevier Ltd. All rights reserved.
Wang L.-J.,Wenhua College |
Han T.,Huazhong University of Science and Technology
Proceedings - 2014 International Conference on Wireless Communication and Sensor Network, WCSN 2014 | Year: 2014
Based on the quadratic function relation between terminal battery energy consumption and transmission power, this paper introduces the relaying scheme of combining cellular networks and Ad Hoc user terminals to establish the single node model of relay selection mechanism, then an optimal relay selection scheme can be proposed constraint to the specific interrupt probability and power allocation. When part of the base stations are in sleep mode to contribute to save costs and energy consumption, the multi-hop nodes as cooperation relays can ensure the normal communication and realize the optimization of energy efficiency, thus saving the costs caused by a large number of fixed relays. © 2014 IEEE.
Zhu H.,Wenhua College |
Wu Y.,Wuhan Institute of Technology
Applied Acoustics | Year: 2016
The digital ultrasonic speckle phase-shifting method (USPM), which is introduced in this paper, can be applied to the measurement of small displacement that is smaller than speckle size at the test point compared to traditional ultrasonic speckle correlation method (USCM). Using USPM, a digital ultrasonic reference signal is introduced to interfere with the ultrasonic speckle signal, which is picked up at the test point on an object surface and is referred to as the object signal. As the phase of the reference signal is shifted several times using the software and then they superimpose with the object signal respectively, the phase of the object signal can be calculated according to the intensities of the superimposed signals. If the object surface moves a small distance, the phase variation of the object speckle can be detected by the same process. As a result, the displacement of the object surface can be measured. Based on the feature of ultrasonic speckles, inner surface displacement of an object can be measured using this proposed method. In this case, the effect of outer surface roughness to the measurement accuracy of USPM is examined experimentally. The experimental results show that the measurement is successful when the displacement is smaller than half of the speckle size at the test point and the roughness parameter Ra of the outer surface of the specimen is less than about 5.47 μm. © 2015 Elsevier Ltd. All rights reserved.
Yu K.,Wenhua College |
Bao J.-Q.,Wenhua College
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2016
When a thin-film filter is used in oblique incidence, the central wavelengths of the polarization light will be separated obviously, and it will cause serious polarization dependent loss. Therefore, this paper designs a 100 GHz channel spacing stack to depolarize in the central wavelength based on the equivalent layer theory and to realize the angle and wavelength tunes of the thin film filter. Firstly, the depolarization equivalent refractive index in the space layer of the filter was calculated by a phase analysis and to complement the alignment of the different polarization lights. Based on the equivalent layer theory, a symmetric three layer stack was designed to replace the depolarization equivalent refractive index of the spacer. As comparing with the original five layer low polarization thin film filter, the three layer spacer stack is simpler, and it is more accurate to replace the depolarization equivalent refractive index. The simulation and experimental results indicate that the stack can align the polarization light central wavelength from 0° to 20°, in which the polarization light separation is less than 0.03 nm and the wavelength tuning range reaches 35 nm. © 2016, Science Press. All right reserved.