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1
Content available Magnified holographic projection based on spatial light modulators
Su Y., Cai Z., Shi L., Zhou F., Chen H., Wu J.
Optica Applicata
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2018
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Vol. 48, nr 4
589--600
EN
In this paper, a magnified holographic projection based on spatial light modulators is proposed and implemented by combining four magnification methods, including similarity principle of Fourier transform, spatial division, digital lens, and image splicing methods. The Fourier holographic display system is constructed for the experimental verification of the proposed methods. With such four methods of holographic magnification, the reconstruction image can be magnified to 10 × 5 times in two-dimensional directions, which is verified by the experiments. Furthermore, the undesirable light of holographic projection is eliminated by encoding the linear phase onto the computer-generated holograms. The experimental results prove that the proposed system can realize magnified holographic projection with good reconstructed quality, which provides a promising potential for the dynamic holographic projector.
2
Content available A scheme of resource allocation and stability for peer-to-peer file-sharing networks
Li S., Sun W., E C. G., Shi L.
International Journal of Applied Mathematics and Computer Science
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2016
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Vol. 26, no. 3
707--719
EN
Peer-to-peer (P2P) networks offer a cost-effective and easily deployable framework for sharing content. However, P2P file-sharing applications face a fundamental problem of unfairness. Pricing is regarded as an effective way to provide incentives to peers to cooperate. In this paper we propose a pricing scheme to achieve reasonable resource allocation in P2P file-sharing networks, and give an interpretation for the utility maximization problem and its sub-problems from an economic point of view. We also deduce the exact expression of optimal resource allocation for each peer, and confirm it with both simulation and optimization software. In order to realize the optimum in a decentralized architecture, we present a novel price-based algorithm and discuss its stability based on Lyapunov stability theory. Simulation results confirm that the proposed algorithm can attain an optimum within reasonable convergence times.
3
Content available Nano-silica reinforced hybrid light-diffusing films with enhanced mechanical and thermal properties
Sun X, Li N., Hang J, Jin L., Shi L, Cheng Z., Shang D
Optica Applicata
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2015
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Vol. 45, nr 3
393--404
EN
Ultraviolet-curable hybrid light-diffusing films with good optical, mechanical and thermal properties were prepared by involving vinyl-silane-modified nano-silica into light-diffusing films. The light-diffusing films were two-phase materials consisting of UV-curable matrix and light-diffusing agent. The effect of three different light-diffusing agents, viz. inorganic layered particle (CaCO3), spherical acrylic resin (MR-7HG) and organosilicone resin (KMP-590) and their contents, on the optical properties of light-diffusing films was studied. The results showed the light-diffusing film exhibited good optical properties (the transmittance was 90.7% and the haze was 95.5%) when KMP-590 was a light-diffusing agent and its content was 25%. It was because that KMP-590 showed good transparency, good dispersion in the UV-curable matrix and the greater difference in refractive index with UV-curable matrix and polycarbonate substrate. Furthermore, the effect of nano-silica on the optical, mechanical and thermal properties of the hybrid light-diffusing films was investigated. Compared to that of the light-diffusing films without nano-silica, the haze of the hybrid light-diffusing films containing nano-silica was lightly enhanced to above 98%, while their transmittance basically remained unchanged at a high value (above 89%). Additionally, scratch and abrasion resistance of the hybrid films were obviously improved by nano-silica especially with the particle size of 10–15 nm. Furthermore, the mechanical property and thermal stability of the hybrid films were improved as the content of nano-silica with the particle size of 10–15 nm increased. The enhanced mechanical property and thermal stability of the films could be attributed to the dense structure induced by the increase in network density with the addition of vinyl-silane-modified nano-silica.
4
Content available remote Modeling and current control strategy for a medium-voltage cascaded multilevel statcom with LCL filter
Zhao X., Shi L., Chen L., Xia Z., Bendre A. R.
Journal of Power Technologies
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2015
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Vol. 95, nr 1
1--13
EN
The Static Synchronous Compensator (STATCOM a.k.a. SVG) is widely used to regulate dynamic reactive power and to solve dynamic voltage stability problems. Modeling shows that a cascaded STATCOM, which is composed of several cascaded H-bridges, not only has strong coupling characteristics when an LCL filter is added but it is also a non-linear, multivariable system. Therefore, its practical design and application are dicult to implement. In this paper an internal decoupling control algorithm is introduced to provide independent control of the active and reactive currents. Decoupling control algorithms are proposed, and models and simulation of the decoupling are provided. We describe the setting up of a simulation and experiments with a cascaded STATCOM based on combined circuit topology with a multi-field programmable gate array (FPGA), and double-loop control algorithms with a current inner loop, and a capacitor voltage outer loop. To provide control of the current inner loop, proportional-integral (PI) and resonant controllers are used, having the control ability to cancel harmonics while compensating for the reactive power. This paper presents new current-tracing control models that compensate for the fundamental current and eliminate selective harmonics by adopting a d-q synchronous reference frame, and a discrete Fourier transform (DFT). Voltage balance is realized by introducing modulation wave distribution strategies. Furthermore, both simulation and experiments are employed to verify the feasibility and eectiveness of the control strategy.
5
Content available Effects of ZnO, CuO, Au, and TiO2 nanoparticles on Daphnia magna and early life stages of zebrafish danio rerio
Liu J., Fan D., Wang L., Shi L., Ding J., Chen Y., Shen S.
Environment Protection Engineering
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2014
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Vol. 40, nr 1
139--149
EN
The effects of four different kinds of nanoparticles (NPs), namely, CuO, ZnO, TiO2, and Au, of the sizes ranging from <20 nm to 50 nm on Daphnia magna, early life stage of zebrafish, and various enzymes have been investigated. The experimental results showed that the NPs inhibited both the body length and hatching rate of zebrafish larvae; the small nanoparticles exhibited more toxicity. In a 21 day chronic toxicity test, metal ions of higher concentrations significantly reduced the number of Daphnia magna offspring. Studies on enzyme activity showed that the NPs reduced the glutathione content and inhibited catalase and superoxide dismutase activities, resulting in shorter body length, lower hatching success, and lower reproduction of zebrafish larvae. Therefore, studies should focus more on the potential toxicity of smaller NPs.
6
Content available remote Design Optimization of QFP Structure for over 8Gbps Package Applications
Sun H., Cai Z., Wu J., Shi L., Sun L.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 1b
284--289
EN
A 8Gbps packaging solution that uses low-cost quad flat pack (QFP) technology is presented. Since such a high speed is beyond the reach of traditional QFP package structure, a new design methodology with coplanar transmission line structure built into the lead frame has been developed. Due to the complexity level in QFP structure, each interconnect segment is accurately modelled in 3D model by utilizing the industry leading advance software tool, ANSYS HFSS. S-parameter, Time Domain Reflectometry (TDR) and Eye Diagram are used to help in understanding the contributing to the optimized QFP structure. The analysis results indicate that the optimized QFP structure can successfully achieve over 8Gbps single-end signal transmission.
PL
W artykule przedstawiono metodę zmiany struktury QFP na potrzeby przesyłu z prędkością 8Gbps. W celu analizy działania, stworzono model struktury o bardzo wysokiej precyzji, przy wykorzystaniu programów ANSYS HFSS. S-parameter, Time Domain Reflectometry (TDR) oraz Eye Diagram. Analiza wyników badań wykazuje, że wprowadzona optymalizacja pozwala na osiągnięcie założonej prędkości przesyłu danych.
7
Content available remote An experimental study on rate sensitivity of J-integral and its evaluation by small punch test for TRIP steel
Shi L., Iwamoto T., Hashimoto Sh.
Engineering Transactions
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2013
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Vol. 61, iss. 2
119--136
EN
Recently, much attention has been paid to TRIP steel since it indicates both high ductility and strength by strain induced martensitic transformation. This transformation allows TRIP steel to offer larger energy absorption than other steel at the same strength level. Therefore, it is expected to be applied to automobiles as security components that absorb energy upon collision. To produce the best performance of TRIP steel, the J-integral of TRIP steel should be investigated with respect to a various deformation rates for an evaluation of energy absorption. In the present study, the three point bending (3B) test is conducted for investigating the Jintegral until the crack growth of TRIP steel. Then, in order to determine the energy absorption characteristic by the J-integral value at various locations in the components of TRIP steel, the size of the specimen should be very small. Thus, an SP test is introduced and conducted by using the newly established apparatus based on the SHPB method. By using the result of the SP test in conjunction with the result of a 3B test, the evaluation of the J-integral of TRIP steel subject to various deflection rates is attempted. The correlation between the J-integral and the equivalent fracture strain of the SP test for TRIP steel is challenged to be redefined.
8
Content available Numerical simulation gob gas field of the roof tunnel drainage method
Qin R. X., Teng L., Yuan S., Shi L.
AGH Journal of Mining and Geoengineering
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2012
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Vol. 36, no. 3
283-290
EN
Roof tunnel drainage is one of the efficient methods of integrated coal exploitation and gas extraction. In order to improve drainage results, a gob gas field of roof tunnel drainage is simulated. As a result of the coal seam occurrence change, the method of downward boreholes from roof tunnel as the amend method is used to increase gas concentration and the quantity of the gas flow. So the gob gas field is compared before and after using the downward boreholes from the roof tunnel. The results show that the range 27m away from the coal face is the gas drainage short area of the roof tunnel method, but the downward boreholes cover it. The downward boreholes acts like a barrier, which prevent gas from flowing to the upper corner in the gob. The gas content in the area from the coalface to 140m on the upper side of the gob is decreased by the roof tunnel with downward boreholes, and this accompanying measure reduces the gas value of upper corner not over the allowable gas limitation.
PL
Odprowadzanie gazu przez chodnik stropowy jest jedną z najbardziej skutecznych metod odmetanowania przy wydobyciu węgla kamiennego. Dla lepszego odprowadzania gazu wykonano symulację gazu ze zrobów przez chodnik stropowy. Zastosowano metodę wiercenia otworów z chodnika stropowego do pokładu węgla w celu zwiększenia stężenia i objętości przepływającego gazu. Porównano zawartości gazu w zrobach przed i po zastosowaniu otworów wiertniczych z chodnika stropowego. Wyniki pokazują, że odległość 27 m od czoła ściany węglowej jest odległością, na której gaz nie może być odprowadzany chodnikiem stropowym jednak dodatkowe otwory wiertnicze zwiększają ujęcie gazu. Otwory tworzą barierę, która zapobiega uchodzeniu gazu do górnych krawędzi zrobów. Zawartość gazu w odległości od czoła ściany do 140 m w górnej części zrobów zmniejsza się dzięki zastosowaniu chodnika z otworami nawierconymi w dół, co przyczynia się do obniżenia stężenia gazu w wyrobisku do wartości poniżej dopuszczalnych.
9
Content available remote Influence of space charged particles on satellite optical communication system
Hou R., Zhao S., Xu J., Wu J., Li Y., Zhan S., Shi L., Fang S.
Optica Applicata
|
2009
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Vol. 39, nr 2
251-265
EN
Although research of satellite optical communication system has been carried out for many years, there is scarce literature to comprehensively analyze the influence of space environment on satellite optical communication system. Different kinds of particles and fields exist in the space environment, including high energy charged particles, solar radiation, plasma environment, space fragment, etc. The Influence of space charged particles on satellite optical communication system was investigated in detail, which mainly related to single event upset (SEU), total dose effect and plasma environment. For SEU analysis the relation between single proton upset rate and satellite orbit was analyzed in detail. The reliability index of equipment based on SEU was proposed, the numerical calculation results have proved that the SEU effect was relatively less and corresponded to higher reliability of SRAM/MOS equipment under lower orbit altitude and inclination. For plasma environment analysis there is no obvious influence of plasma on laser signal transmission. But charging and discharging processes on satellite surface would lead to the malfunction of satellite communication system. The influence of charged particles and its related plasma on satellite optical communication system was investigated, which would be helpful for the design and the improvement of performance of satellite optical communication system.
10
Content available Charge transfer fluctuations as a QGP signal
Jeon S., Shi L., Bleicher M.
Nukleonika
|
2006
|
Vol. 51,suppl.3
65-68
EN
In this study, we analyze the recently proposed charge transfer fluctuations within a finite pseudorapidity space. As the charge transfer fluctuation is a measure of the local charge correlation length, it is capable of detecting inhomogeneity in the hot and dense matter created by heavy-ion collisions. We predict that going from peripheral to central collisions, the charge transfer fluctuations at midrapidity should decrease substantially while the charge transfer fluctuations at the edges of the observation window should decrease by a small amount. These are consequences of having a strongly inhomogeneous matter where the QGP component is concentrated around midrapidity. We also show how to constrain the values of the charge correlations lengths in both the hadronic phase and the QGP phase using the charge transfer fluctuations. Current manuscript is based on the two recent papers [10, 13].
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