Wyniki wyszukiwania - BazTech

1

A novel testing setup for determining the flexural properties of tunnel segmental joints: Development and application

Zhang Z. X., Liu W., Zhuang Q. W., Huang X., Wang S. F., Zhang C., Zhu Y. T., Kwok C. Y.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 3

724--738

EN

A novel testing setup is developed for structural tests on segmental joints of shield tunnels. It lies on the ground and is a self-balanced system. The applied axial force and bending moment are coupled, and the combination of target axial force and bending moment at the joint can be achieved by adjusting the horizontally-applied forces. It is more economic and flexible than the traditional two-point bending testing setups. The effectiveness of internal force/moment transmission of the testing setup was verified by comparing the experimental data with theoretically-determined values and numerical simulation results. It was then applied to investigate the flexural behaviour of longitudinal joint of a deeply-buried tunnel subjected to both sagging and hogging moments. The rotational stiffnesses of the testing joint were determined. The influences of bending moment and axial force on joint defor-mation were unified through eccentricity. In both the sagging moment and hogging moment cases, the joint deformation varied with eccentricity following a bilinear trend composed of an axial-force-dominant stage and a bending-moment-dominant stage. The slopes of the relationships between eccentricity and joint rotation angle are steeper in the hogging moment case than in the sagging moment case due to the absence of bolts at the extrados.

2

Quinoxaline-based small molecules: synthesis and investigation on their optoelectronic properties

Deng J., Tao Q., Yan D., Huang X., Liao Y.

Materials Science Poland

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2018

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Vol. 36, No. 2

167--176

EN

Small molecules of ThQuTh, CzQuTh, CzQuCz and TPAQuCz were designed and synthesized, based on quinoxaline acceptor, and electron donating groups, i.e. alkyl-thioephene, carbazole and triphenylamine on both side chains and molecular backbones. Their thermal, optical and electrochemical properties were systematically compared and studied. The absorption spectra of the small molecules were strongly affected by the donor units attached to quinoxaline. Strong electron donating groups, such as carbazole on the molecular backbone would lower optical band gap, resulting in a wide absorption and the strong donor on the side chain would enhance the absorption intensity in short wavelength region. The highest occupied molecular orbital (HOMO) energy levels of the four molecules were up-shifted with increasing the electron donating properties of donor units. The bulk-heterojunction organic solar cells with a device structure of ITO/PEDOT:PSS/SMs:PC61BM/LiF/Al were fabricated, in which the small molecules functioned as donors while PC61BM as acceptor. Because the electron-donating ability of carbazole (Cz), triphenylamine (TPA) is higher than that of thiophene (Th), CzQuTh, CzQuCz and TPAQuCz show higher power conversion efficiency (PCE) than that of ThQuTh. Furthermore, being the strongest in absorption intensity and widest in absorption spectrum, TPAQuCz has the highest power conversion efficiency. Further improvement of the device efficiency by optimizing the device structure is currently under investigation

3

Numerical modeling of Gaussian beam propagation and diffraction in inhomogeneous media based on the complex eikonal equation

Huang X., Sun H.

Acta Geophysica

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2018

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Vol. 66, no. 4

497--508

EN

Gaussian beam is an important complex geometrical optical technology for modeling seismic wave propagation and diffraction in the subsurface with complex geological structure. Current methods for Gaussian beam modeling rely on the dynamic ray tracing and the evanescent wave tracking. However, the dynamic ray tracing method is based on the paraxial ray approximation and the evanescent wave tracking method cannot describe strongly evanescent fields. This leads to inaccuracy of the computed wave fields in the region with a strong inhomogeneous medium. To address this problem, we compute Gaussian beam wave fields using the complex phase by directly solving the complex eikonal equation. In this method, the fast marching method, which is widely used for phase calculation, is combined with Gauss–Newton optimization algorithm to obtain the complex phase at the regular grid points. The main theoretical challenge in combination of this method with Gaussian beam modeling is to address the irregular boundary near the curved central ray. To cope with this challenge, we present the non-uniform finite difference operator and a modified fast marching method. The numerical results confirm the proposed approach.

4

Full-automatic computer aided system for stem cell clustering using content-based microscopic image analysis

Li C., Huang X., Jiang T., Xu N.

Biocybernetics and Biomedical Engineering

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2017

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Vol. 37, no. 3

540--558

EN

Stem cells are very original cells that can differentiate into other cells, tissues and organs, which play a very important role in biomedical treatments. Because of the importance of stem cells, in this paper we propose a full-automatic computer aided clustering system to assist scientists to explore potential co-occurrence relations between the cell differentiation and their morphological information in phenotype. In this proposed system, a multi-stage Content-based Microscopic Image Analysis (CBMIA) framework is applied, including image segmentation, feature extraction, feature selection, feature fusion and clustering techni-ques. First, an Improved Supervised Normalized Cuts (ISNC) segmentation algorithm is newly introduced to partition multiple stem cells into individual regions in an original microscopic image, which is the most important contribution in this paper. Then, based on the seg-mented stem cells, 11 different feature extraction approaches are applied to represent the morphological characteristics of them. Thirdly, by analysing the robustness and stability of the extracted features, Hu and Zernike moments are selected. Fourthly, these two selected features are combined by an early fusion approach to further enhance the properties of the feature representation of stem cells. Finally, k-means clustering algorithm is chosen to classify stem cells into different categories using the fused feature. Furthermore, in order to prove the effectiveness and usefulness of this proposed system, we carry out a series of experiments to evaluate our methods. Especially, our ISNC segmentation obtains 92.4% similarity, 96.0% specificity and 107.8% ration of accuracy, showing the potential of our work.

5

Analysis of the influence of the transducer and its coupling layer on round window stimulation

Liu H., Xu D., Yang J., Yang S., Cheng G., Huang X.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 2

103--111

EN

Purpose: In this work, a finite element study is proposed to evaluate the effects of the transducer and its coupling layer on the performance of round window (RW) stimulation. Methods: Based on a set of micro-computer tomography images of a healthy adult’s right ear and reverse engineering technique, a coupled finite-element model of the human ear and the transducer was constructed and verified. Then, the effect of the cross-section of the transducer, the elastic modulus of the coupling layer, the mass of the transducer, and the preload of the transducer were studied. Results: The increase of the transducer’s cross-section area deteriorates the RW stimulation, especially at the lower frequencies. This adverse effect of the cross-section area’s increase of the transducer can be reduced by adding a coupling layer between the transducer and the RW. However, the coupling layer’s improvement on the RW stimulation is reduced with the increase of its elastic modulus. Moreover, the mass loading of the transducer decreases the RW stimulation’s performance mainly at higher frequencies and applying a static preload on the transducer enhances its hearing compensating performance at higher frequencies. Conclusions: The influence of the transducer’s mass, the mass of the transducer, the applied static preload and the properties of the coupling layer must be taken into account in the design of the RW stimulation type implantable middle ear hearing device.

6

Analysis on the operating characteristic of UHVDC new hierarchical connection mode to AC system

Sun J., Fu R., Tang Y., Sun W. Q., Huang X.

Journal of Power Technologies

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2016

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Vol. 96, nr 4

229--237

EN

The UHVDC system plays an important role in smart grids. In this paper, a new topology structure of UHVDC hierarchical connection mode to different AC systems is analyzed with a view to improving system transmission abilities. Then a new mathematical model is proposed to calculate the MIIF under different UHVDC hierarchical connection modes. The effect of coupling impedance, equivalent impedance and different DC control mode adopted by two group inverters are illustrated to analyze the MIIF. The method to calculate the MISCR of the multi-infeed HVDC system is also applied to HISCR of UHVDC hierarchical connection mode with the MIIF value. In UHVDC hierarchical connection mode, total power to different hierarchical active current layer can be allocated reasonably to change parameter of the received power grid. Thus, the commutation failure can be analyzed according the MIIF change values of UHVDC hierarchical connection mode to the AC system. Therefore, it may increase the risk of commutation failure in the other converter when one converter is in a state of commutation failure. The correctness of the proposed method is verified by PSCAD simulation. The simulation results are illustrated to verify the operating characteristics of the system.

7

Simulation of deformation and fracture characteristics of a 45 steel taylor impact specimen

Chen G., Huang X.

Engineering Transactions

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2016

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Vol. 64, iss. 2

225--240

EN

The Taylor impact test was originally developed as a method for estimating the dynamic strength of ductile materials at high strain rates. More recently, the Taylor test has been used to verify material constitutive models by comparing numerical predictions with experimental data, since it provides a wide range of plastic strains and strain rates in various stress states. When the impact velocity is sufficiently high, a specimen will generate cracks in the Taylor test. Only few studies investigated so far the fracture phenomena and mechanisms in the Taylor test. In this paper, based on investigation of material dynamic behaviour, the deformation and fracture characteristics of a 45 steel specimen under Taylor impact test were simulated using axial symmetry and three-dimensional model was developed with LS-DYNA software. The final length and diameter of the specimen, obtained in simulations, were consistent with the experimental observations. Different dynamic fractures that occurred in the Taylor test were obtained in three-dimensional numerical simulations as well. The mechanisms of different failure modes were investigated using the history of stress state triaxiality of the specimen.

8

Reversible Spiking Neural P Systems with Astrocytes

Kong Y., Shi X., Xu J., Huang X.

Fundamenta Informaticae

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2015

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Vol. 136, nr 3

219--230

EN

Spiking neural P systems with astrocytes (SNPA systems, for short) are a class of distributed parallel computing devices inspired from the way neurons communicate by means of spikes. In this work, we investigate the reversibility in SNPA systems as well as the computational power of reversible SNPA systems. It is proved that reversible SNPA systems are universal, where the forgetting rules and the feature of delay in spiking rules are not used, and each neuron contains only one spiking rule. The result suggests that the astrocytes play a key role in the functioning of reversible SNPA systems.

9

Experimental and Numerical Investigation on Compression Orthotropic Properties of Spruce Wood in Axial and Transverse Loading Directions

Zhong W, Rusinek A., Jankowiak T., Huang X., Abed F.

Engineering Transactions

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2014

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Vol. 62, iss. 4

381–-401

EN

Compression tests on spruce wood in axial, radial and tangential directions have been performed using an INSTRON hydraulic machine. Spruce elastic mechanical properties and plastic deformation behaviour are presented. Experimental results allow to demonstrate different spruce failure modes: fibers buckling and collapsing are noticed under axial compression whereas, fibers slippage and delamination are the main failure modes under compression loading in radial and tangential directions. Spruce energy absorption efficiency and ideality energy absorption efficiency in the three loading directions are also analyzed. Representative volume element (RVE) model is adopted assuming transverse isotropic behavior to simulate wood microstructure in all directions. It was shown that micro-cell arrangement leads to wood macromechanical property spatial anisotropy. Porosity and hole shape effects on simulation results are estimated by RVE models with hexagon, circle, pentagon and square holes.

10

Finite Element analysis for Edge-to-Edge Technique to Treat Post-Mitral Valve Repair Systolic Anterior Motion

Zhong Q., Zeng W., Huang X., Zhao X.

Acta of Bioengineering and Biomechanics

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2014

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Vol. 16, no. 4

3--12

EN

Systolic anterior motion of the mitral valve is an uncommon complication of mitral valve repair, which requires immediate supplementary surgical action. Edge-to-edge suture is considered as an effective technique to treat post-mitral valve repair systolic anterior motion by clinical researches. However, the fundamentals and quantitative analysis are vacant to validate the effectiveness of the additional edge-to-edge surgery to repair systolic anterior motion. In the present work, finite element models were developed to simulate a specific clinical surgery for patients with posterior leaflet prolapse, so as to analyze the edge-to-edge technique quantificationally. The simulated surgery procedure concluded several actions such as quadrangular resection, mitral annuloplasty and edge-to-edge suture. And the simulated results were compared with echocardiography and measurement data of the patients under the mitral valve surgery, which shows good agreement. The leaflets model with additional edge-to-edge suture has a shorter mismatch length than that of the model merely under quadrangular resection and mitral annuloplasty actions at systole, which assures a better coaptation status. The stress on the leaflets after edge-to-edge suture is lessened as well.

11

The Development of Drilling Engineering Monitoring System Using Wireless Sensor Networks

Yang G., Ma Z., Xu W., Huang X., Zhou J.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1b

37--40

EN

In order to avoid defects of existing drilling engineering monitoring and alarming system, such as the sensors and cable which are difficult to be installed and easy to be damaged, this paper present a new embedded drilling engineering monitoring system which is based on Wireless Sensor Network(WSN) and Wireless Local Area Networks(WLAN). The system is consists of the data acquisition subsystem, duty room controller, tool-pusher room controller and engineer room controller. It acquired the data and exported control commands by WSN. The tool-pusher room controller and engineer room controller are communicated with the duty room controller by WLAN for remote monitoring. For the special field drilling environment, the system achieves the acquiring, transmission, the export of control commands and remote monitoring of drilling data.

PL

Obecnie stosowany system monitorowania I alarmowania w technice wiercenia posiada szereg wad związanych z czujnikami i kablami, które trudno instalować i łatwo uszkodzić. Zaprezentowany w opracowaniu nowy system pozwala na uniknięcie tych wad. Oparty jest o bezprzewodową sieć czujnikową (WSN) oraz bezprzewodową sieć lokalną (WLAN). System obejmuje gromadzenie, transmisję danych i przekazywanie sygnałów sterowania oraz zdalne monitorowania danych wiercenia.

12

Analysis of Monitoring and Numerical Simulation on Anchor Force of Foundation Pit

Wang G., Zhang Q., Huang X., Tu X.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

216--220

EN

Pile anchor supporting structure is a common method in deep foundation pit engineering. To a certain extent, anchor forces can reflect the earth pressure acting on the supporting structures. In the process of the deep foundation pit construction, the layers with different types of groundwater are often encountered. Improper control of groundwater may lead to engineering safety problems and many other cases which can cause bad effects on the surrounding environment. Therefore, it is of practical significance to conduct the optimal designs for supporting structures of deep foundation pit by monitoring the anchor forces in-situ. Through studying and analyzing the monitoring data, the earth pressure’s magnitude and distribution law can be further understood. In this paper, foundation pit engineering is taken as a base, a whole monitoring of the actual anchor forces is made in the process of tensioning, locking and working of anchors, and the monitoring data is analyzed. A numerical analysis based on the fluid-solid coupling theory of unsaturated soil is performed, and tests of the soil water characteristic curve (SWCC) for typical unsaturated soil are carried out. Finally, the test results are applied to numerical analysis. The results of anchor forces calculated by considering the coupled condition and ignoring the groundwater’s effect are compared with the monitoring results of engineering site. The comparison indicates that numerical results are inconsistent with measured results. The numerical results are close to the measured results only when the fluid-solid coupling theory of unsaturated soil is considered.

PL

W artykule przedstawiono wyniki badań dotyczących budowy głębokich fundamentów oraz ich utrzymania, w odniesieniu do ich odporności na pojawiające się czynniki (siły) zewnętrzne. Analizie poddano dane dotyczące sił kotwiczących fundamentów, zapewniających stabilność budowli, a w szczególności tzw. roztwór glebowy. Otrzymane wyniki zostały porównane z wynikami badań nie uwzględniającymi roztworu glebowego oraz wielkościami pomierzonymi. W ten sposób wykazano duży wpływ tego czynnika na wyniki analiz.

13

The Dynamic Model of Closed-Loop Supply Chain with Product Recovering and its Robust Control

Qiu R., Huang X., Lu Z.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

1-4

EN

In recent years, closed-loop supply chain (CLSC) operation has been an important method to recover waste materials and products for resource conservation and environmental protection and paid more attention in industry and academia. We establish a dynamic model for closedloop supply chain with product recovering with the consideration of some uncertainties including remanufacturing rate, disposal rate, operation costs and customers’ demand in this paper. Furthermore, we provide some insights about robust operation of closed-loop supply chain and propose a robust H∞ control strategy based on linear matrix inequality (LMI) arithmetic. Some simulations are executed to validate the effectiveness of our control strategy, and the results show that through state feedback control of supply chain inventories, it can not only make the CLSC achieve the goal of restraining uncertainty disturbances, but also result in an ideal operation cost.

PL

Closed loop supply chain (CLCP – zamknięta pętla łańcucha zasobów) jest dziś ważną metodą odzyskiwania zmarnowanego materiału i produktu w celu ochrony środowiska i konserwacji zasobów. Zaproponowano model dynamiczny uwzględniający niepewności typu tempo produkcji, tempo usuwania, koszty operacyjne i żądania klienta.

14

Research of the GIS Structure Influence on Propagation Characteristic of Partial Discharge Electromagnetic Waves

Li Q., Qiu W., Cai W., Sheng G., Liu Y., Huang X., Jiang X.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 3b

149-155

EN

Partial discharge process caused by Gas Insulatd Switchgear (GIS) typical insulation defect is mainly analyzed in this study, and propagation properties of electromagnetic waves in actual GIS structure are investigated by applying FDTD algorithm and using real PD current signal as excitation source. The results show that great difference occurs between electromagnetic waves excited by PD actual current signal and that by ideal Gaussian pulse excitation and basin type insulator, shielding electrodes and three-phase common enclosure can affect the amplitude, frequency component and propagation mode of electromagnetic waves. The electromagnetic waves signal intensity is not necessarily proportional to its distance from discharge source; the proportion of frequency components is proportional to the diameter of GIS shell when it propagate in breakers.

PL

Zaprezentowano stadium wyładowania niezupełnego przy typowych defektach łączników gazowych. Zastosowano metodę różnic skończonych. Zaobserwowano istotne różnice fali elektromagnetycznej przy rzeczywistym wyładowaniu w stosunku do modelu teoretycznego. Sygnał fali elektromagnetycznej jest proporcjonalny do średnicy powłoki wyłącznika.

15

Performance Investigation of Induction Heater

Lu Q., Huang X., Ye Y., Fang Y.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9a

277-280

EN

To achieve high and even-distributed temperature of the rotatory part, an induction heater is designed and its performance of different structure is investigated. By the erected electromagnetic model, structure parameters including height, length and position of induction copper layer are optimized. Its temperature distribution is obtained based on another coupled-field model combining electromagnet field with temperature field. The predicted results show not only the steady temperature distribution, but also the temperature dynamic variation, which are also validated by the prototype measurement. Since the test temperature can almost keep constant and uniform with corresponding temperature controller, the proposed induction heater meets the design requirement.

PL

Zaprojektowano nagrzewnicę indukcyjną do nagrzewania ruchomych elementów. Optymalizowano parametry, takie jak wysokość, długość I pozycja wartwy miedzianej.

16

Experiment and analysis of high power line-start PM motor

Lu Q., Huang X., Ye Y., Fang Y.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 2

274-277

EN

This paper investigates the performance of a high power line-start permanent-magnet motor (LSPM) by experiment, which is developed for industrial fans, pumps and compressors to reduce the energy consumption. The no-load back-EMF is measured and compared with predicted result of FEM. In order to assess the line starting ability, the rotor-locked test is carried out and then the starting torque ratio is deduced which is lower than that of induction motor of the same power. By adjusting the load, the efficiency and power factor during all operation condition are obtained. It is found this proposed LSPM has not only higher power factor and efficiency, but also high overload ability. After its starting ability of reduced voltage is analyzed, several useful methods are pointed out for designing high power LSPM which should start with limited current.

PL

Zbadano właściwości silnika wysokiej mocy LSPM w zastosowaniu przemysłowym do pomp, wentylatorów i kompresorów pod kątem redukcji zużycia energii. Zbadano silnik przy zablokowanym wirniku i na tej podstawie przewidywano moment startowy. Przy zmianie obciążenia określono współczynnik mocy i sprawność.

17

A New Multi-objective Optimization Algorithm: MOAFSA and its Application

Fang G., Guo W., Huang X., Si X., Yang F., Luo Q., Yan K.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

172-176

EN

This paper proposes a multi-objective artificial fish swarm algorithm (MOAFSA), which imitates the behaviors of fish for local search, uses the quick sort method to get non-dominated solution set, and cuts the external set according to the crowding distance. This paper firstly uses MOAFSA for multi-objective functions test. Results show that MOAFSA has a faster convergence speed and the corresponding Pareto set is more evenly distributed; then MOAFSA is applied in the scheduling optimization of hydropower station reservoir.

PL

Przedstawiono nowy algorytm optymalizacyjny MOAFSA (multiobjective artificial fish swarm algorithm) bazujący na ławicy ryb. Algorytm sprawdzono na przykładzie projektowania obciążeń hydroelektrowni.

18

Interference effect in a dual microresonator-coupled Mach-Zehnder interferometer

Lu Y., Huang X., Fu X., Wen W., Yao J.

Optica Applicata

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2012

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Vol. 42, nr 1

23-29

EN

We present a theoretical study of interference effect in a Mach-Zehnder interferometer in which two microresonators are side coupled to both arms of the interferometer. The results show that sharp asymmetric Fano resonance, coupled resonator induced transparency and absorption effects can be created in such a structure. We demonstrate that these effects arise from interference between a resonance mode and a continuing propagating mode with asymmetric phase difference, destructive interference between two overcoupled resonance modes, and constructive interference between an overcoupled resonance mode and an undercoupled mode or a continuing propagating mode with symmetric phase differences, respectively. These effects may offer a better understanding of the analogous effects in atomic medium and also make optical resonators a potential device to utilize these effects.

19

Surface plasmon resonance sensor based on photonic crystal fiber filled with silver nanowires

Fu X., Lu Y., Huang X., Hao C., Wu B., Yao J.

Optica Applicata

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2011

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Vol. 41, nr 4

941--951

EN

Silver nanowire filled photonic crystal fibers are proposed in this paper to achieve surface plasmon resonance sensors and overcome the complicacy and difficulty of coating the holes in the photonic crystal fiber. Optical field distributions of these fibers at different wavelengths are calculated and simulated using the finite element method (FEM), and the sensing properties are discussed in both areas of resonant wavelength and intensity detection. Numerical simulation results show that carefully designed structure of the sensor brings about an excellent effect, with both spectral and intensity sensitivity in the range of 4×10-5-5×10-5 RIU, better than in the case of similar structures coated with metal film, and the fabrication is expected to be simplified.

20

The Crystal Structure of Zn(II) Complex of Rhodamine B{Zn(RB)(OAc)2 H2O, RB=9-[2-Ethoxycarbonyl)phenyl]-3,6-bis(ethylamino)-2,7-dimethylxanthylium} : The First Solid Free Radical Species of Rhodamine B Metal Complexes

Zhang H., Lin Q., Wang L., Mu L., Huang X.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 5

639-647