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Full-Text Articles in Physical Sciences and Mathematics
Optical Sensing System Based On Wireless Paired Emitter Detector Diode Device And Ionogels For Lab-On-A-Disc Water Quality Analysis, Monika Czugala, Robert Gorkin Iii, Thomas Phelan, Jennifer Gaughran, Vincenzo Curto, Jens Ducree, Dermot Diamond, Fernando Benito-Lopez
Optical Sensing System Based On Wireless Paired Emitter Detector Diode Device And Ionogels For Lab-On-A-Disc Water Quality Analysis, Monika Czugala, Robert Gorkin Iii, Thomas Phelan, Jennifer Gaughran, Vincenzo Curto, Jens Ducree, Dermot Diamond, Fernando Benito-Lopez
Robert Gorkin III
This work describes the first use of a wireless paired emitter detector diode device (PEDD) as an optical sensor for water quality monitoring in a lab-on-a-disc device. The microfluidic platform, based on an ionogel sensing area combined with a low-cost optical sensor, is applied for quantitative pH and qualitative turbidity monitoring of water samples at point-of-need. The autonomous capabilities of the PEDD system, combined with the portability and wireless communication of the full device, provide the flexibility needed for on-site water testing. Water samples from local fresh and brackish sources were successfully analysed using the device, showing very good correlation …
Nonlinear Optical Conductivity Of Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling In Terahertz Regime, Yee Sin Ang, J C. Cao, Chao Zhang
Nonlinear Optical Conductivity Of Two-Dimensional Semiconductors With Rashba Spin-Orbit Coupling In Terahertz Regime, Yee Sin Ang, J C. Cao, Chao Zhang
Yee Sin Ang
We reveal that two-dimensional semiconductors with Rashba spin-orbit interaction (R2DG) exhibit exceptionally strong nonlinear optical response (NOR) in the terahertz frequency regime. The spin-split of the parabolic energy band in R2DG allows strong multiple-photon process to occur via inter-subband mechanism. We show sharp multiple photon edges in the nonlinear conductivity. The edges correspond to the cut-off effect produced by the multiple-photon process. For Rashba coupling parameter of λ R ≈ 10−10 eV m, electric field strength in the order of only 102 V/cm is required for the NOR to dominate over the linear response. Furthermore, the roles of the parabolic …
The Jahn–Teller Effect And Electron–Phonon Interaction In La0.25ca0.75mn1−Xcrxo3, H. Zhou, G. Li, H. Chen, R. Zheng, Xiaojuan Fan, X. Li
The Jahn–Teller Effect And Electron–Phonon Interaction In La0.25ca0.75mn1−Xcrxo3, H. Zhou, G. Li, H. Chen, R. Zheng, Xiaojuan Fan, X. Li
Xiaojuan Fan
The ultrasonic (longitudinal and transverse) velocities and the transport and magnetic properties of polycrystalline La0.25Ca0.75Mn1-xCrxO3 (x = 0, 0.03, 0.05, and 0.07) have been studied systematically. It was found that with increasing Cr content, the resistivity increases, the charge-ordering transition temperature TCO shifts to low temperature, and the magnetic moment of the system is strengthened. From the temperature dependence of the ultrasonic velocities, one can establish that the Jahn-Teller energy and phonon exchange constant decrease with increasing Cr content.
Optical Switching Of Protein Interactions On Photosensitive-Electroactive Polymers Measured By Atomic Force Microscopy, Amy Gelmi, Michele Zanoni, Michael J. Higgins, Sanjeev Gambhir, David L. Officer, Dermot Diamond, Gordon G. Wallace
Optical Switching Of Protein Interactions On Photosensitive-Electroactive Polymers Measured By Atomic Force Microscopy, Amy Gelmi, Michele Zanoni, Michael J. Higgins, Sanjeev Gambhir, David L. Officer, Dermot Diamond, Gordon G. Wallace
Gordon Wallace
The ability to switch the physico-chemical properties of conducting polymers opens up new possibilities for a range of applications. Appropriately functionalised materials can provide routes to multi-modal switching, for example, in response to light and/or electrochemical stimuli. This capability is important in the field of bionics wherein remote and temporal control of the properties of materials is becoming attractive. The ability to actuate a film via photonic stimuli is particularly interesting as it facilitates the modulation of interactions between host binding sites and potential guest molecules. In this work, we studied two different poly-terthiophenes: one was functionalised with a spiropyran …
Flux Distribution In Fe-Based Superconducting Materials By Magneto-Optical Imaging, Zhi Wei Lin, Jian Guo Zhu, You Guang Guo, Xiaolin Wang, S X. Dou, Tom H. Johansen, Xun Shi, K Y. Choi
Flux Distribution In Fe-Based Superconducting Materials By Magneto-Optical Imaging, Zhi Wei Lin, Jian Guo Zhu, You Guang Guo, Xiaolin Wang, S X. Dou, Tom H. Johansen, Xun Shi, K Y. Choi
Shi Xue Dou
"This paper presents the magnetic flux distributions in Fe-based superconducting materials including single crystal of Ba(Fe1.9Ni0.1)As2 and Ba(Fe1.8Co0.2)As2, as well as polycrystalline SmFeO0.75F0.2As by means of magneto-optical imaging (MOI) technique. The single crystals were grown out of FeAs flux while polycrystalline sample was grown by hot-press. A MOI film with in-plan magnetization was used to visualize flux distributions at the sample surface. A series of magneto-optical images was taken when the samples were zero-field cooled and field cooled. The flux behavior, including penetration into and expelling from the samples, as well as pinning properties were studied. When external fields increase, …
Progress In Optical Dating Of Guano-Rich Sediments Associated With The Deep Skull, West Mouth Of The Great Cave Of Niah, Sarawak, Borneo, Mark Stephens, Richard Roberts, O Lian, Hiroyuki Yoshida
Progress In Optical Dating Of Guano-Rich Sediments Associated With The Deep Skull, West Mouth Of The Great Cave Of Niah, Sarawak, Borneo, Mark Stephens, Richard Roberts, O Lian, Hiroyuki Yoshida
Richard G Roberts
The West Mouth of the Great Cave of Niah is one of the major archaeological sites in Southeast Asia; the radiocarbon chronology of this site currently places the earliest presence of Homo sapiens (a Deep Skull find) in Southeast Asia at about 45 ka BP. An optical dating programme using sand-sized quartz was initiated in the West Mouth to complement the radiocarbon chronology. This paper reports on the progress in dating a key sample (sample 376r) that was taken from deposits containing the Deep Skull. A somewhat novel procedure was developed to separate and clean quartz grains from the unusual …
Equivalent Dose Distributions From Single Grains Of Quartz At Sibudu, South Africa: Context, Causes And Consequences For Optical Dating Of Archaeological Deposits, Richard Roberts, Zenobia Jacobs, Geoffrey Duller, Ann Wintle
Equivalent Dose Distributions From Single Grains Of Quartz At Sibudu, South Africa: Context, Causes And Consequences For Optical Dating Of Archaeological Deposits, Richard Roberts, Zenobia Jacobs, Geoffrey Duller, Ann Wintle
Richard G Roberts
No abstract provided.
Optical Dating Of Perennially Frozen Deposits Associated With Preserved Ancient Plant And Animal Dna In North-Central Siberia, Richard Roberts, Lee Arnold, F Brock, E Willerslev, A Tikhonov, R Macphee
Optical Dating Of Perennially Frozen Deposits Associated With Preserved Ancient Plant And Animal Dna In North-Central Siberia, Richard Roberts, Lee Arnold, F Brock, E Willerslev, A Tikhonov, R Macphee
Richard G Roberts
No abstract provided.
Single-Grain Optical Dating Of Grave-Infill Associated With Human Burials At Lake Mungo Australia, Jonathon Olley, Richard Roberts, Hiroyuki Yoshida, James M Bowler
Single-Grain Optical Dating Of Grave-Infill Associated With Human Burials At Lake Mungo Australia, Jonathon Olley, Richard Roberts, Hiroyuki Yoshida, James M Bowler
Richard G Roberts
Recent age constraints on Australia's oldest human remains (Mungo I and III), found at Lake Mungo in western New South Wales, relied on optical dating of sands from the same stratigraphic units as those into which the remains had been inserted (42±3 ka) and those that overlay the graves (38±2 ka), giving a burial age of 40±2 ka. This indirect means of dating the burials was necessary because the original site from which the remains had been excavated had been completely eroded away. At the time of the original excavation of the Mungo III grave, blocks of sediment from the …
A Revised Burial Dose Estimation Procedure For Optical Dating Of Young And Modern-Age Sediments, Richard Roberts, Lee Arnold, R.F. Galbraith, S Delong
A Revised Burial Dose Estimation Procedure For Optical Dating Of Young And Modern-Age Sediments, Richard Roberts, Lee Arnold, R.F. Galbraith, S Delong
Richard G Roberts
No abstract provided.
Propagation Of Optical Spatial Solitary Waves In Bias-Free Nematic-Liquid-Crystal Cells, Antonmaria A. Minzoni, Luke W. Sciberras, Noel F. Smyth, Annette L. Worthy
Propagation Of Optical Spatial Solitary Waves In Bias-Free Nematic-Liquid-Crystal Cells, Antonmaria A. Minzoni, Luke W. Sciberras, Noel F. Smyth, Annette L. Worthy
Associate Professor Annette Worthy
The propagation of a bulk optical solitary wave in a rectangular cell filled with a nematic liquid crystal—a nematicon—is mathematically modelled. In order to overcome the Freédricksz threshold the cell walls are rubbed to pretilt the nematic. A modulation theory, based on a Lagrangian formulation, is developed for the (2+1)-dimensional propagation of the solitary wave beam down the cell. This modulation theory is based on two different formulations of the director distribution. The relative advantages and disadvantages of these two methods are discussed. A previously unexplored method based on images is found to possess significant advantages. Excellent agreement with full …
Fpga-Based Signal Processing In An Optical Feedback Self-Mixing Interferometry System, Zongzhen Li, Yanguang Yu, Jiangtao Xi, Huiying Ye
Fpga-Based Signal Processing In An Optical Feedback Self-Mixing Interferometry System, Zongzhen Li, Yanguang Yu, Jiangtao Xi, Huiying Ye
Dr Yanguang Yu
Optical feedback Self-mixing Interferometry (OFSMI) can achieve a high-resolution displacement sensing and measurement by using advanced digital signal processing. However, most existing signal processing algorithms used for OFSMI signals are implemented on a PC by Matlab or other programming languages. In this case, the whole structure of OFSMI sensing system is incompact and the measurement is in low speed. The design trends in sensing systems are towarding to small size, high integration and fast real time processing. These trends require us to improve the existing OFSMI design. It is a good solution to apply Field-programmable gate arrays (FPGAs) technique onto …
The Fourier Spectrum Analysis Of Optical Feedback Self-Mixing Signal Under Weak And Moderate Feedback, Xiaojun Zhang, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo
The Fourier Spectrum Analysis Of Optical Feedback Self-Mixing Signal Under Weak And Moderate Feedback, Xiaojun Zhang, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo
Dr Yanguang Yu
The spectrum characteristics of self-mixing signals observed in optical feedback self-mixing interferometry (OFSMI) is studied in this paper. The purpose is to provide guidance for the design of pre-processing techniques for eliminating noise or disturbance. The influence of two important parameters of the OFSMI system on the spectrum, that is, the optical feedback factor and the linewidth enhancment factor, are measured by means of Discrete Fourier transform (DFT). The simulated results show that, at a weak feedback, the OFSMI signals are strictly band limited in nature, with the cut-off frequencies being the vibration frequency and the fringe frequency respectively. Also …
Fast Digital Optical Flow Estimation Based On Emd, Mickael Quelin, Abdesselam Bouzerdoum, Son Lam Phung
Fast Digital Optical Flow Estimation Based On Emd, Mickael Quelin, Abdesselam Bouzerdoum, Son Lam Phung
Professor Salim Bouzerdoum
This paper presents an optical flow estimation technique based on the so called Elementary Motion Detector (EMD). The aim is to provide a fast but not necessarily very accurate system to be used for specific post processing purposes. This model uses a low complexity algorithm for detecting motion in four directions by identifying specific motion templates. By extending the motion templates to different scales of the input video, an Elementary Velocity Detector (EVD) is created. This one can save computation time by estimating different speeds in parallel. Information from the EVD outputs is then used to generate an estimate of …
The Fourier Spectrum Analysis Of Optical Feedback Self-Mixing Signal Under Weak And Moderate Feedback, Xiaojun Zhang, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo
The Fourier Spectrum Analysis Of Optical Feedback Self-Mixing Signal Under Weak And Moderate Feedback, Xiaojun Zhang, Jiangtao Xi, Yanguang Yu, Joe F. Chicharo
Professor Joe F. Chicharo
The spectrum characteristics of self-mixing signals observed in optical feedback self-mixing interferometry (OFSMI) is studied in this paper. The purpose is to provide guidance for the design of pre-processing techniques for eliminating noise or disturbance. The influence of two important parameters of the OFSMI system on the spectrum, that is, the optical feedback factor and the linewidth enhancment factor, are measured by means of Discrete Fourier transform (DFT). The simulated results show that, at a weak feedback, the OFSMI signals are strictly band limited in nature, with the cut-off frequencies being the vibration frequency and the fringe frequency respectively. Also …
Fpga-Based Signal Processing In An Optical Feedback Self-Mixing Interferometry System, Zongzhen Li, Yanguang Yu, Jiangtao Xi, Huiying Ye
Fpga-Based Signal Processing In An Optical Feedback Self-Mixing Interferometry System, Zongzhen Li, Yanguang Yu, Jiangtao Xi, Huiying Ye
Professor Jiangtao Xi
Optical feedback Self-mixing Interferometry (OFSMI) can achieve a high-resolution displacement sensing and measurement by using advanced digital signal processing. However, most existing signal processing algorithms used for OFSMI signals are implemented on a PC by Matlab or other programming languages. In this case, the whole structure of OFSMI sensing system is incompact and the measurement is in low speed. The design trends in sensing systems are towarding to small size, high integration and fast real time processing. These trends require us to improve the existing OFSMI design. It is a good solution to apply Field-programmable gate arrays (FPGAs) technique onto …