Journals >Optoelectronics Letters
Contents
2015
Volume: 11 Issue 6
19 Article(s)
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Research Article
Template-directed synthesis of Ag nanowire arrays by a simple paired cell method for SERS
Jia-qing MO, Jun-wei HOU, and Xiao-yi Lü
The silver (Ag) nanowire arrays with regular and uniform size were successfully fabricated inside the nanochannels of anodic aluminum oxide (AAO) template by a simple paired cell method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicate that the as-synthesized samples are composed of face-The silver (Ag) nanowire arrays with regular and uniform size were successfully fabricated inside the nanochannels of anodic aluminum oxide (AAO) template by a simple paired cell method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicate that the as-synthesized samples are composed of face-centered cubic structure, and the average diameter is about 60–70 nm. Transmission electron microscopy (TEM) and the corresponding fast Fourier transformation (FFT) results show that Ag nanowires have a preferred single-crystal structure. Ultraviolet- visible (UV-vis) spectrum of Ag nanowire arrays exhibits UV emission band at 383 nm which can be attributed to the transverse dipole resonance of Ag nanowire arrays. A good surface-enhanced Raman scattering (SERS) spectrum is observed by excitation with a 514.5 nm laser, and the intensity of the SERS peak is about 23 times higher than that of the normal Raman peak measured from an empty AAO template. The high enhancement factor suggests that this method can be used to fabricate SERS sensor with high efficiency..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 401 (2015)
Effect of growth time on morphology and photoelectrochemical performance of TiO2nanorod arrays grown on transparent conducting substrates
Mei-rong SUI, Cui-ping HAN, Xiu-quan GU, Yong WANG, Lu TANG, and Hui TANG
TiO2nanorod arrays (NRAs) were synthesized directly on the fluorine tin oxide (FTO) coated glass substrates by a facile hydrothermal route. The effects of growth time on the photoelectrochemical (PEC) properties of TiO2NRAs are investigated. The samples synthesized for 4 h exhibit a photocurrent intensity of 0.37 mA/cmTiO2nanorod arrays (NRAs) were synthesized directly on the fluorine tin oxide (FTO) coated glass substrates by a facile hydrothermal route. The effects of growth time on the photoelectrochemical (PEC) properties of TiO2NRAs are investigated. The samples synthesized for 4 h exhibit a photocurrent intensity of 0.37 mA/cm2at the irradiation of Xe lamp and a bias of 0 V. As the growth time increases, the thickness and order degree of the NRAs are enhanced, but the photocurrent is reduced a lot. It might be associated with the hindering of a high background electron density in NRs due to the long-time hydrothermal reaction in acid environment. Moreover, the decline behavior is observed, which is attributed to the poor charge separation capacity of TiO2array electrodes and could be suppressed efficiently by applying a suitable positive bias..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 405 (2015)
Stereo imaging quality evaluation in a full-color threedimensional display system
Wei DUAN, Xin-zhu SANG, Xun-bo YU, Xin GAO, Zhi-dong CHEN, Yue WANG, Bin-bin YAN, Jin-hui YUAN, Kui-ru WANG, Chong-xiu YU, Wen-hua DOU, and Li-quan XIAO
To evaluate the light field display system with a liquid crystal display (LCD) and a holographic functional screen (HFS), the voxel theory based on the ray tracing is used. By analyzing the voxels defined by the cases of corresponding pixels overlapping completely and partially in the image space, the resolution characTo evaluate the light field display system with a liquid crystal display (LCD) and a holographic functional screen (HFS), the voxel theory based on the ray tracing is used. By analyzing the voxels defined by the cases of corresponding pixels overlapping completely and partially in the image space, the resolution characteristics of the system are discussed. The theoretical model is verified in the reconstruction experiment of a resolution target and compared with the calculation result of the presented system. Finally, we give an optimization method for the display image quality..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 410 (2015)
Multi-band polarization insensitive metamaterial absorber with dual cross-wires structure
Li-fang YAO, Min-hua LI, Xiao-min ZHAI, Hui-bo WANG, and Jian-feng DONG
A five-band metamaterial absorber (MMA) based on a simple planar structure is proposed. It utilizes different areas of a single unit cell to match impedance, and produces different absorptive frequencies. Numerical calculation shows that the MMA has five different absorption peaks at 3.78 GHz, 7.66 GHz, 10.9 GHz, 14.5 A five-band metamaterial absorber (MMA) based on a simple planar structure is proposed. It utilizes different areas of a single unit cell to match impedance, and produces different absorptive frequencies. Numerical calculation shows that the MMA has five different absorption peaks at 3.78 GHz, 7.66 GHz, 10.9 GHz, 14.5 GHz and 16.7 GHz, and their absorption rates reach 95.5%, 98.6%, 95.7%, 96.6% and 99.8%, respectively. The proposed structure is polarization insensitive for transverse electric (TE) and transverse magnetic (TM) incident waves. Also, the absorptive characteristics over large incident angles are examined. In addition, we analyze the absorption mechanism by the surface current density and power flow density distributions. This simple structure provides a way to design multi-band MMA, and also saves the cost of fabrication..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 414 (2015)
A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection
Feng WANG, Wei-hong BI, Xing-hu FU, Peng JIANG, and Yang WU
In this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss aIn this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss are equal, so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature. The experimental results show that the laser can output stable multi-wavelength lasers simultaneously. The laser coupling loss is small, the structure is simple, and it is convenient for integration, so it can be widely used in dense wavelength division multiplexing (DWDM) system and optical fiber sensors..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 418 (2015)
Ring cavity fiber laser based on Fabry-Pérot interferometer for high-sensitive micro-displacement sensing
Yan BAI, Feng-ping YAN, Shuo LIU, Si-yu TAN, and Xiao-dong WEN
A ring cavity fiber laser based on Fabry-Pérot interferometer (FPI) is proposed and demonstrated experimentally for micro-displacement sensing. Simulation results show that the dips of the FPI transmission spectrum are sensitive to the cavity length of the FPI. With this characteristic, the relationship between waA ring cavity fiber laser based on Fabry-Pérot interferometer (FPI) is proposed and demonstrated experimentally for micro-displacement sensing. Simulation results show that the dips of the FPI transmission spectrum are sensitive to the cavity length of the FPI. With this characteristic, the relationship between wavelength shift and cavity length change can be established by means of the FPI with two aligned fiber end tips. The maximum sensitivity of 39.6 nm/μm is achieved experimentally, which is approximately 25 times higher than those in previous reports. The corresponding ring cavity fiber laser with the sensitivity for displacement measurement of about 6 nm/μm is implemented by applying the FPI as the filter. The proposed fiber laser has the advantages of simple structure, low cost and high sensitivity..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 421 (2015)
Luminescent properties of blue emitting phosphor SrZn2(PO4)2:Eu2+for white LEDs
Wei LU, Yu-fei LIU, Ying WANG, Zhi-jun WANG, and Li-bin PANG
Blue emitting phosphor SrZn2(PO4)2:Eu2+ is synthesized by a high temperature solid state method, and the luminescent properties are investigated. At the 330 nm radiation excitation, SrZn2(PO4)2:Eu2+ presents an emission band at 416 nm, which is assigned to the 4f65d1→4f7 transition of Eu2+ion. The concentration quenchiBlue emitting phosphor SrZn2(PO4)2:Eu2+ is synthesized by a high temperature solid state method, and the luminescent properties are investigated. At the 330 nm radiation excitation, SrZn2(PO4)2:Eu2+ presents an emission band at 416 nm, which is assigned to the 4f65d1→4f7 transition of Eu2+ion. The concentration quenching effect of Eu2+in SrZn2(PO4)2has been validated and proved to be a resonant type via a dipole-dipole interaction. The critical distance (Rc) of Eu2+in SrZn2(PO4)2is calculated to be 3.244 nm. The Commission International de I’Eclairage (CIE) chromaticity coordinates of SrZn2(PO4)2:Eu2+ locate at the blue region, such as (0.150, 0.072). The results indicate that the SrZn2(PO4)2:Eu2+ phosphor may have potential applications in white light emitting diodes (LEDs)..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 426 (2015)
Improving the luminescence properties of Ba3Eu(PO4)3by doping Sm3+as sensitizer
Jian-qi YOU, Wei LU, Shuai QI, Ya-min LI, Xian SHI, Zhi TIAN, Zhi-jun WANG, Kun ZHANG, and Li-bin PANG
For enhancing the emission intensity and broadening the excitation region of Ba3Eu(PO4)3(BEP), Sm3+is doped as sensitizer in this paper. BEP:Sm3+can produce an obvious red emission at near ultraviolet (n-UV) radiation. An effective energy transfer from Sm3+to Eu3+is proved. The commission international de I’Eclairage (For enhancing the emission intensity and broadening the excitation region of Ba3Eu(PO4)3(BEP), Sm3+is doped as sensitizer in this paper. BEP:Sm3+can produce an obvious red emission at near ultraviolet (n-UV) radiation. An effective energy transfer from Sm3+to Eu3+is proved. The commission international de I’Eclairage (CIE) chromaticity coordinates of BEP:Sm3+locate at red region. When the environment temperature is 150 °C, the emission intensity of BEP:0.10Sm3+is decreased to 76% of the initial one at room temperature, and the activation energy is calculated to be 0.164 eV, which can prove the good thermal stability of BEP:Sm3+. The results indicate that BEP:Sm3+may have potential applications in white light emitting diodes (LEDs)..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 430 (2015)
A temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers
Xing-hu FU, Qin LIU, Yan-li XIU, Hai-yang XIE, Chuan-qing YANG, Shun-yang ZHANG, Guang-wei FU, and Wei-hong BI
In this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multIn this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multi-mode fiber (SMMF), two sensors with different temperature sensing properties are obtained, and experimental results show that the temperature sensitivity can be up to 48.76 pm/°C in the range of 25—95 °C. Moreover, it has many advantages, including small size, high sensitivity, and simple structure. So it can be used in potential temperature sensing applications, such as industrial production, biomedical science, power electronics, and so on..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 434 (2015)
All fiber sensor based on Mach-Zehnder interferometer for simultaneous measurement of temperature and refractive index
Ye CAO, Chen ZHAO, and Zheng-rong TONG
In this paper, we propose and experimentally demonstrate a compact optical fiber sensor based on a Mach-Zehnder interferometer (MZI) cascaded with fiber Bragg grating (FBG) for simultaneous measurement of refractive index (RI) and temperature. In order to get a proper spectrum, we discuss the effects of different strucIn this paper, we propose and experimentally demonstrate a compact optical fiber sensor based on a Mach-Zehnder interferometer (MZI) cascaded with fiber Bragg grating (FBG) for simultaneous measurement of refractive index (RI) and temperature. In order to get a proper spectrum, we discuss the effects of different structure parameters of MZI. Using the resonant wavelength of the FBG (DipFBG) and the interference dip of the MZI (Dip1), the RI and temperature of the surrounding medium can be determined. The sensor has good operation linearity. The experimental results show that the distinctive spectral sensitivities are 0.071 75 nm/°C and -91.766 67 nm/RIU (refraction index unit) for Dip1 and 0.009 09 nm/°C for DipFBG..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 438 (2015)
Multi-service small-cell cloud wired/wireless access network based on tunable optical frequency comb
Yu XIANG, Kun ZHOU, Liu YANG, Lei PAN, Zhen-wan LIAO, and Qiang ZHANG
In this paper, we demonstrate a novel multi-service wired/wireless integrated access architecture of cloud radio access network (C-RAN) based on radio-over-fiber passive optical network (RoF-PON) system, which utilizes scalable multiple- frequency millimeter-wave (MF-MMW) generation based on tunable optical frequency cIn this paper, we demonstrate a novel multi-service wired/wireless integrated access architecture of cloud radio access network (C-RAN) based on radio-over-fiber passive optical network (RoF-PON) system, which utilizes scalable multiple- frequency millimeter-wave (MF-MMW) generation based on tunable optical frequency comb (TOFC). In the baseband unit (BBU) pool, the generated optical comb lines are modulated into wired, RoF and WiFi/WiMAX signals, respectively. The multi-frequency RoF signals are generated by beating the optical comb line pairs in the small cell. The WiFi/WiMAX signals are demodulated after passing through the band pass filter (BPF) and band stop filter (BSF), respectively, whereas the wired signal can be received directly. The feasibility and scalability of the proposed multi-service wired/wireless integrated C-RAN are confirmed by the simulations..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 444 (2015)
A new LDPC decoding scheme for PDM-8QAM BICM coherent optical communication system
Yi LIU, Wen-bo ZHANG, Li-xia XI, Xian-feng TANG, and Xiao-guang ZHANG
A new log-likelihood ratio (LLR) message estimation method is proposed for polarization-division multiplexing eight quadrature amplitude modulation (PDM-8QAM) bit-interleaved coded modulation (BICM) optical communication system. The formulation of the posterior probability is theoretically analyzed, and the way to reduA new log-likelihood ratio (LLR) message estimation method is proposed for polarization-division multiplexing eight quadrature amplitude modulation (PDM-8QAM) bit-interleaved coded modulation (BICM) optical communication system. The formulation of the posterior probability is theoretically analyzed, and the way to reduce the pre-decoding bit error rate (BER) of the low density parity check (LDPC) decoder for PDM-8QAM constellations is presented. Simulation results show that it outperforms the traditional scheme, i.e., the new post-decoding BER is decreased down to 50% of that of the traditional post-decoding algorithm..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 449 (2015)
A novel chromatic dispersion monitoring method for 400 Gbit/s 256 QAM fiber-optic system based on asynchronous amplitude sampling
Hui-jun WU, Bo ZHU, Guo-qing LIU, Jia-wei SHEN, and Fang-ren HU
A novel chromatic dispersion (CD) monitoring technique based on asynchronous amplitude sampling (AAS) is proposed for a higher modulation format and higher rate system. The dispersion and other impairment factors can be separated with the definition of monitoring parameter M. A 400 Gbit/s 256 quadrature amplitude modulA novel chromatic dispersion (CD) monitoring technique based on asynchronous amplitude sampling (AAS) is proposed for a higher modulation format and higher rate system. The dispersion and other impairment factors can be separated with the definition of monitoring parameter M. A 400 Gbit/s 256 quadrature amplitude modulation (QAM) system is built using Optisystem13.0 beta software. Simulations of CD monitoring technique for different bandwidths of sampling Gaussian filter, optical signal to noise ratios (OSNRs) and duty cycles are investigated, and the tolerance is also discussed. Simulation results show that the method can be less affected by noise, and a higher accuracy of 600 ps/(nm·km) can be achieved. The technique supports a wide range of data traffic and enhances operation flexibility of optical networks..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 453 (2015)
Performance of CO-OFDM system with RS-Turbo concatenated code
Zheng-rong TONG, Gui-bin HU, Ye CAO, and Wei-hua ZHANG
In this paper, the RS-Turbo concatenated code is applied to coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. RS(186,166,8) and Turbo code with code rate of 1/2 are employed for RS-Turbo concatenated code. Two decoding algorithms, which are Max-Log-MAP algorithm and Log-MAP algorithm, are adIn this paper, the RS-Turbo concatenated code is applied to coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. RS(186,166,8) and Turbo code with code rate of 1/2 are employed for RS-Turbo concatenated code. Two decoding algorithms, which are Max-Log-MAP algorithm and Log-MAP algorithm, are adopted for Turbo decoding, and the iteration Berlekamp-Massey (BM) algorithm is adopted for RS decoding. The simulation results show that the bit error rate (BER) performance of CO-OFDM system with RS-Turbo concatenated code is significantly improved at high optical signal to noise ratio (OSNR), and the iteration number is reduced compared with that of the Turbo coded system. Furthermore, when the Max-Log-MAP algorithm is adopted for Turbo decoding, the transmission distance of CO-OFDM system with RS-Turbo concatenated code can reach about 400 km without error, while that of the Turbo coded system can only reach about 240 km when BER is lower than 10-4 order of magnitude..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 457 (2015)
Non-reciprocity compensation correction and antenna selection for optical large MIMO system
Jie CHEN, Xue-fen CHI, and Lin-lin ZHAO
This paper exploits an optical large multiple input multiple output (MIMO) system. We first establish the non-reciprocity compensation correction factor to solve the channel non-reciprocity problem. Then we propose an antenna selection algorithm with the goal of realizing maximum energy efficiency (EE) when satisfying This paper exploits an optical large multiple input multiple output (MIMO) system. We first establish the non-reciprocity compensation correction factor to solve the channel non-reciprocity problem. Then we propose an antenna selection algorithm with the goal of realizing maximum energy efficiency (EE) when satisfying the outage EE. The simulation results prove that this non-reciprocity compensation correction factor can compensate beam energy attenuation gap and spatial correlation gap between uplink and downlink effectively, and this antenna selection algorithm can economize the number of transmit antennas and achieve high EE performance. Finally, we apply direct current- biased optical orthogonal frequency division multiplexing (DCO-OFDM) modulation in our system and prove that it can improve the bit error rate (BER) compared with on-off keying (OOK) modulation, so the DCO-OFDM modulation can resist atmospheric turbulence effectively..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 461 (2015)
A temperature sensor based on switchable dual- wavelength fiber Bragg grating laser with a semiconductor saturable absorber mirror
Qi LI, Kai-qiang HUANG, and Hai-yan CHEN
A temperature sensor based on a switchable dual-wavelength fiber Bragg grating (FBG) laser with a semiconductor saturable absorber mirror (SESAM) is presented and demonstrated experimentally. The repetition rate of Q-switched pulses is ~17 kHz. The results demonstrate that the measured temperature has good linearity toA temperature sensor based on a switchable dual-wavelength fiber Bragg grating (FBG) laser with a semiconductor saturable absorber mirror (SESAM) is presented and demonstrated experimentally. The repetition rate of Q-switched pulses is ~17 kHz. The results demonstrate that the measured temperature has good linearity to the wavelength spacing of the two lasing wavelengths and has a temperature sensitivity of 21 pm/oC covering a range of -10—22 °C. The experimental results prove the feasibility of the proposed temperature sensor..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 466 (2015)
Mid-infrared carbon monoxide detection system using differential absorption spectroscopy technique
Ming DONG, Yue SUI, Guo-lin LI, Chuan-tao ZHENG, Mei-mei CHEN, and Yi-ding WANG
A differential carbon monoxide (CO) concentration sensing device using a self-fabricated spherical mirror (e.g. light-collector) and a multi-pass gas-chamber is presented in this paper. Single-source dual-channel detection method is adopted to suppress the interferences from light source, optical path and environmentalA differential carbon monoxide (CO) concentration sensing device using a self-fabricated spherical mirror (e.g. light-collector) and a multi-pass gas-chamber is presented in this paper. Single-source dual-channel detection method is adopted to suppress the interferences from light source, optical path and environmental changes. Detection principle of the device is described, and both the optical part and the electrical part are developed. Experiments are carried out to evaluate the sensing performance on CO concentration. The results indicate that at 1.013×105Pa and 298 K, the limit of detection (LoD) is about 11.5 mg/m3 with an absorption length of 40 cm. As the gas concentration gets larger than 115 mg/m3(1.013×105Pa, 298 K), the relative detection error falls into the range of -1.7%—+1.9%. Based on 12 h long-term measurement on the 115 mg/m3and 1 150 mg/m3CO samples, the maximum detection errors are about 0.9% and 5.5%, respectively. Due to the low cost and competitive characteristics, the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 469 (2015)
Multi-view coordinate system transformation based on robot
Li-mei SONG, Peng-qiang WANG, Jiang-tao XI, Qing-hua GUO, Huan TANG, Jing LI, Xiao-jie LI, and Teng-da ZHU
The registration of point cloud is important for large object measurement. A measurement method for coordinate system transformation based on robot is proposed in this paper. Firstly, for obtaining extrinsic parameters, the robot moves to three different positions to capture the images of three targets. Then the transfThe registration of point cloud is important for large object measurement. A measurement method for coordinate system transformation based on robot is proposed in this paper. Firstly, for obtaining extrinsic parameters, the robot moves to three different positions to capture the images of three targets. Then the transformation matrix X between camera and tool center point (TCP) coordinate systems can be calculated by using the known parameters of robot and the extrinsic parameters, and finally the multi-view coordinate system can be transformed into robot coordinate system by the transformation matrix X. With the help of robot, the multi-view point cloud can be easily transformed into a unified coordinate system. By using robot, the measurement doesn’t need any mark. Experimental results show that the method is effective..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 473 (2015)
Spatial modulation characteristics of single-photon frequency up-conversion systems pumped by Gaussian laser beam
Jian-hui MA, Xiong-jie LI, Wen-jie WU, Kun HUANG, Hai-feng PAN, and E WU
In a Gaussian laser beam pumped single-photon frequency up-conversion system, the spatial distribution of the conversion efficiency is calculated, which strongly depends on the intensity distribution of the pump beam and leads to a spatial modulation of the output single photons. As a result, by simply varying the GausIn a Gaussian laser beam pumped single-photon frequency up-conversion system, the spatial distribution of the conversion efficiency is calculated, which strongly depends on the intensity distribution of the pump beam and leads to a spatial modulation of the output single photons. As a result, by simply varying the Gaussian pump beam intensity and the beam size, the converted photons could be modulated spatially and exhibit a programmable distribution. This will be meaningful for the researches on quantum communication and quantum manipulation based on frequency up-conversion system..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 11, Issue 6, 477 (2015)
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