Engineering Commons^™

Evaluation And Analysis Of New Method Of Measurement Of Target Scattering Matrix, Zhenyu Huang, Zhao Bo, Huanyao Dai, Liandong Wang, Xuequan Zhou

Journal of System Simulation

Abstract: The basic theory of radar polarization signal processing is measurement of the target scattering matrix. The current algorithm of measurement of the target scattering matrix is gotten through orthogonal dual polarization channel in time-sharing or simultaneously, which demands orthogonal polarization measurement signals with complex coding. The measuring accuracy is higher. The complexity and the cost of the system are relatively higher. Scattering matrix can also be obtained by making use of the spatial polarization characteristics of the antenna to processing the radar echo without structure reformation of the radar. It only. needs to renewal measurement technology. The comparison and …

A Computationally-Efficient Bound For The Variance Of Measuring The Orientation Of Single Molecules, Tingting Wu, Tianben Ding, Hesam Mazidi, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Modulating the polarization of excitation light, resolving the polarization of emitted fluorescence, and point spread function (PSF) engineering have been widely leveraged for measuring the orientation of single molecules. Typically, the performance of these techniques is optimized and quantified using the Cramér-Rao bound (CRB), which describes the best possible measurement variance of an unbiased estimator. However, CRB is a local measure and requires exhaustive sampling across the measurement space to fully characterize measurement precision. We develop a global variance upper bound (VUB) for fast quantification and comparison of orientation measurement techniques. Our VUB tightly bounds the diagonal elements of the …

Polarization Properties Of Airy And Ince-Gaussian Laser Beams, Sean Michael Nomoto

Graduate Theses and Dissertations

The description of polarization states of laser light as linear, circular polarization within the paraxial scalar wave approximation is adequate for most applications. However, this description falls short when considering laser light as an electromagnetic wave satisfying Maxwell's equations. An electric field with a constant unit vector for direction of the field and a space dependent complex scalar amplitude in the paraxial wave approximation does not satisfy Maxwell equations which, in general, requires all three Cartesian components of electric and magnetic fields associated for a nonzero laser beam to be nonzero.

Physical observation of passing a linearly polarized laser through …

Perovskite R3c Phase Agcuf3: Multiple Dirac Cones, 100% Spin Polarization And Its Thermodynamic Properties, Minquan Kuang, Tingzhou Li, Zhenxiang Cheng, Houari Khachai, Rabah Khenata, Tie Yang, Tingting Lin, Xiaotian Wang

Australian Institute for Innovative Materials - Papers

Very recently, experimentally synthesized R3c phase LaCuO3 was studied by Zhang, Jiao, Kou, Liao & Du [J. Mater. Chem. C (2018), 6, 6132-6137], and they found that this material exhibits multiple Dirac cones in its non-spin-polarized electronic structure. Motivated by this study, the focus here is on a new R3c phase material, AgCuF3, which has a combination of multiple Dirac cones and 100% spin polarization properties. Compared to the non-spin-polarized system LaCuO3, the spin-polarized Dirac behavior in AgCuF3 is intrinsic. The effects of on-site Coulomb interaction, uniform strain and spin-orbit coupling were added to examine the stability of its multiple …

Spin Response Function For Spin Transparency Mode Of Rhic, V. S. Morozov, P. Adams, Y. S. Derbenev, Y. Filatov, H. Huang, A. M. Kondratenko, M. A. Kondratenko, F. Lin, F. Méot, V. Ptitsyn, W. B. Schmidke, Y. Zhang

Engineering Technology Faculty Publications

In the Spin Transparency (ST) mode of RHIC, the axes of its Siberian snakes are parallel. The spin tune in the ST mode is zero and the spin motion becomes degenerate: any spin direction repeats every particle turn. In contrast, the lattice of a conventional collider determines a unique stable periodic spin direction, so that the collider operates in the Preferred Spin (PS) mode. Contributions of perturbing magnetic fields to the spin resonance strengths in the PS mode are usually calculated using the spin response function. However, in that form, it is not applicable in the ST mode. This paper …

Experimental Verification Of Transparent Spin Mode In Rhic, V. S. Morozov, P. Adams, Y. S. Derbenev, Y. Filatov, H. Huang, A. M. Kondratenko, M. A. Kondratenko, F. Lin, F. Méot, V. Ptitsyn, W. B. Schmidke, Y. Zhang

Engineering Technology Faculty Publications

High electron and ion polarizations are some of the key design requirements of a future Electron Ion Collider (EIC). The transparent spin mode, a concept inspired by the figure 8 ring design of JLEIC, is a novel technique for preservation and control of electron and ion spin polarizations in a collider or storage ring. It makes the ring lattice "invisible" to the spin and allows for polarization control by small quasi-static magnetic fields with practically no effect on the beam’s orbital characteristics. It offers unique opportunities for polarization maintenance and control in Jefferson Lab’s JLEIC and in BNL’s eRHIC. The …

Electrostatic Design And Conditioning Of A Triple Point Junction Shield For A −200 Kv Dc High Voltage Photogun, G. Palacios-Serrano, F. Hannon, C. Hernandez-Garcia, M. Poelker, H. Baumgart

Electrical & Computer Engineering Faculty Publications

Nuclear physics experiments performed at the Continuous Electron Beam Accelerator Facility (CEBAF) at the Jefferson Lab require a DC high voltage photogun to generate polarized electron beams from GaAs photocathodes. The photogun uses a tapered ceramic insulator that extends into the vacuum chamber and mechanically holds the cathode electrode. Increasing the operating voltage from nominal −130 kV to −200 kV will provide lower beam emittance, better transmission through injector apertures, and improved photocathode lifetime. This desire to increase the photogun operating voltage led to the design of a triple-point-junction shield electrode which minimizes the electric field at the delicate insulator-metal-vacuum …

Remote Sensing Of Soil Moisture Using S-Band Signals Of Opportunity: Model Development And Experimental Validation, Marvin Jesse, Benjamin Nold, James L. Garrison

The Summer Undergraduate Research Fellowship (SURF) Symposium

Root zone soil moisture (RZSM) is a vital aspect in meteorology, hydrology, and agriculture. There are currently some methods in passive and active remote sensing at L-band, but these methods are limited to a sensing depth of approximately 10 cm. Observing RZSM (water in the top meter of soil) will require lower frequencies, thus presenting significant difficulties for a spaceborne instrument, because of the required antenna size, the presence of radio-frequency interference (RFI), and competition for spectrum allocations (in the case of active radar). Bistatic radar using Signal of Opportunity (SoOp) (e.g. digital satellite transmitters) provides an opportunity for remote …

An Investigation Of The Synergistic Effect Between (1,3-Dioxolan-2-Ylmethyl)Triphenylphosphonium Bromide And Iodide Ion For The Corrosion Inhibition Of Zinc In Citric Acid, Saadawy M.

Journal of Electrochemistry

The effect of (1,3-Dioxolan-2-ylmethyl)-triphenylphosphonium bromide (DTPB) on the zinc corrosion in 0.5 mol·L^-1 citric acid solution was investigated at 30 ^oC using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. An ecofriendly bath was used for acid cleaning of zinc, which has not been widely used in literatures. The results showed that DTPB could serve as an effective inhibitor for the zinc corrosion in a citric acid solution with the inhibition efficiency of 98.9% at the DTPB concentration of 3×10^-3 mol·L^-1. A synergistic effect between DTPB and potassium iodide (KI) enhanced the inhibition …

Peeking Into The Other Half Of The Glass : Handling Polarization In Recommender Systems., Mahsa Badami

Electronic Theses and Dissertations

This dissertation is about filtering and discovering information online while using recommender systems. In the first part of our research, we study the phenomenon of polarization and its impact on filtering and discovering information. Polarization is a social phenomenon, with serious consequences, in real-life, particularly on social media. Thus it is important to understand how machine learning algorithms, especially recommender systems, behave in polarized environments. We study polarization within the context of the users' interactions with a space of items and how this affects recommender systems. We first formalize the concept of polarization based on item ratings and then relate …

Relaxation Rate And Polarization Charge Density Model For Aln/Al$_{X}$Ga$_{1 - X}$N/Aln Heterostructures, Nagarajan Sivarajan, Reeba Korah, Mariya Kalavathy Ganamani

Turkish Journal of Electrical Engineering and Computer Sciences

This work describes the strain-relaxation--dependent carrier concentration ($n_{s})$ profile model using spontaneous and piezoelectric polarization for AlN/Al$_{x}$Ga$_{1 - x}$N/AlN HEMTs in all mole fraction ($x)$ interpolations. As $x$ varies, the Aluminum Gallium Nitride (AlGaN) channel shows strain relaxation with the Aluminum Nitride (AlN) barrier. The degree of relaxation is modeled from AlN to GaN regions in the channel. It shows that the AlN barrier and buffer relaxation and strain recovery occurs due to the gradual crystal quality degradation from barrier/buffer to the channel interface. These combination devices show less drain current degradation with temperature variation from 300 K to 573 …

Beyond Conventional C-Plane Gan-Based Light Emitting Diodes: A Systematic Exploration Of Leds On Semi-Polar Orientations, Morteza Monavarian

Theses and Dissertations

Despite enormous efforts and investments, the efficiency of InGaN-based green and yellow-green light emitters remains relatively low, and that limits progress in developing full color display, laser diodes, and bright light sources for general lighting. The low efficiency of light emitting devices in the green-to-yellow spectral range, also known as the “Green Gap”, is considered a global concern in the LED industry. The polar c-plane orientation of GaN, which is the mainstay in the LED industry, suffers from polarization-induced separation of electrons and hole wavefunctions (also known as the “quantum confined Stark effect”) and low indium incorporation efficiency that …

The Effects Of Strain And Vacancies On The Electric And Vibrational Properties Of Ferroelectric Batio3 From First-Principles, Aldo Serge Michael Raeliarijaona

Graduate Theses and Dissertations

The studies of ferroelectricity (FE) are of technological significance because of the multitude of applicable properties that ferroelectric materials exhibit. The mastery, and control of these properties necessitate the knowledge of the fundamental physics governing these insulating materials.

In this dissertation I present the results of first-principles investigations of the behavior of the fundamental ferroelectric properties under strain, and in the presence of vacancies. In the first part I introduce the important FE properties, their common behavior, and their numerous valuable applications. Following this background on FEs, a review of theoretical methods is presented with topics such as: Density Functional …

Ultrafast Spin Polarization In A Multiferroic Manganite Bife0.5mn0.5o3 Thin Film, Zeyu Zhang, Zuanming Jin, Xian Lin, Zhenxiang Cheng, H Y. Zhao, Hideo Kimura, Guohong Ma

Australian Institute for Innovative Materials - Papers

In this work, we present observations of ultrafast carrier dynamics and spin polarization in a multiferroic manganite BiFe0.5Mn0.5O3 film excited by linearly and circularly polarized femtosecond pulses, respectively. The d-band charge transfer transition is reasonably assigned to Γ3 → Γ5. The transient reflectivity decay on a time scale as fast as only 0.3 ps is consistent with the picture of ultrafast electron-phonon coupling. The ultrafast switching of polarization ellipticity (< 150 fs) originates from a transient coherent spin polarization by optical orientation. The ultrafast spin polarization switching is assigned to the Raman coherence process.

A Low Temperature Nonlinear Optical Rotational Anisotropy Spectrometer For The Determination Of Crystallographic And Electronic Symmetries, Darius H. Torchinsky, Hao Chu, Tongfei Qi, Gang Cao, David Hsieh

Center for Advanced Materials Faculty Publications

Nonlinear optical generation from a crystalline material can reveal the symmetries of both its lattice structure and underlying ordered electronic phases and can therefore be exploited as a complementary technique to diffraction based scattering probes. Although this technique has been successfully used to study the lattice and magnetic structures of systems such as semiconductor surfaces, multiferroic crystals, magnetic thin films, and multilayers, challenging technical requirements have prevented its application to the plethora of complex electronic phases found in strongly correlated electron systems. These requirements include an ability to probe small bulk single crystals at the μm length scale, a need …

Polarization Alignment, Phase Transition, And Piezoelectricity Development In Polycrystalline 0.5ba(Zr0.2 Ti0.8)O3-0.5(Ba0.7 Ca0.3)Tio3, Hanzheng Guo, Brian K. Voas, Shujun Zhang, Chao Zhou, Xiaobing Ren, Scott P. Beckman, Xiaoli Tan

Australian Institute for Innovative Materials - Papers

The microstructural origin of the exceptionally high piezoelectric response of polycrystalline 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 is investigated using in situ transmission electron microscopy, in addition to a wide variety of bulk measurements and first-principles calculations. A direct correlation is established relating a domain wall-free state to the ultrahigh piezoelectric d33 coefficient in this BaTiO3-based composition. The results suggest that the unique single-domain state formed during electrical poling is a result of a structural transition from coexistent rhombohedral and tetragonal phases to an orthorhombic phase that has an anomalously low elastic modulus. First-principles calculations indicate that incorporating Ca2+ and Zr4+ into BaTiO3 reduces the …

Orbital Structure Of Fetio3 Ilmenite Investigated With Polarization-Dependent X-Ray Absorption Spectroscopy And Band Structure Calculations, S W. Chen, M J. Huang, P A. Lin, H T. Jeng, J M. Lee, S C. Haw, S A. Chen, H J. Lin, K T. Lu, Dapeng Chen, S X. Dou, X L. Wang, J M. Chen

Shi Xue Dou

We explored the orbital structure of FeTiO3 with polarization-dependent x-ray absorption spectra complemented with electronic structure calculations. The electronic structure, near the bottom of conduction band, is composed of O 2p and Ti 3d orbitals. Ti 3d/4p hybridization dominantly lies on the ab plane. The highly delocalized Ti 4p orbital might hybridize with O 2p orbital and even extend to the next-neighbor Fe atom whereby establishing a linear orbital combination of Ti-O-Fe. A clear picture of the orbital construction in FeTiO3 will help to elucidate the paths of pressure-induced charge transfer and other physical or magnetic characteristics.

Inverse Problems In Multiple Light Scattering, John Broky

Electronic Theses and Dissertations

The interaction between coherent waves and material systems with complex optical properties is a complicated, deterministic process. Light that scatters from such media gives rise to random fields with intricate properties. It is common perception that the randomness of these complex fields is undesired and therefore is to be removed, usually through a process of ensemble averaging. However, random fields emerging from light matter interaction contain information about the properties of the medium and a thorough analysis of the scattered light allows solving specific inverse problems. Traditional attempts to solve these kinds of inverse problems tend to rely on statistical …

Magneto-Photonic Crystals For Optical Sensing Applications, Neluka Dissanayake

Dissertations, Master's Theses and Master's Reports - Open

Among the optical structures investigated for optical sensing purpose, a significant amount of research has been conducted on photonic crystal based sensors. A particular advantage of photonic crystal based sensors is that they show superior sensitivity for ultra-small volume sensing. In this study we investigate polarization changes in response to the changes in the cover index of magneto-optic active photonic band gap structures. One-dimensional photonic-band gap structures fabricated on iron garnet materials yield large polarization rotations at the band gap edges. The enhanced polarization effects serve as an excellent tool for chemical sensing showing high degree of sensitivity for photonic …

Orbital Structure Of Fetio3 Ilmenite Investigated With Polarization-Dependent X-Ray Absorption Spectroscopy And Band Structure Calculations, S W. Chen, M J. Huang, P A. Lin, H T. Jeng, J M. Lee, S C. Haw, S A. Chen, H J. Lin, K T. Lu, Dapeng Chen, S X. Dou, X L. Wang, J M. Chen

Australian Institute for Innovative Materials - Papers

We explored the orbital structure of FeTiO3 with polarization-dependent x-ray absorption spectra complemented with electronic structure calculations. The electronic structure, near the bottom of conduction band, is composed of O 2p and Ti 3d orbitals. Ti 3d/4p hybridization dominantly lies on the ab plane. The highly delocalized Ti 4p orbital might hybridize with O 2p orbital and even extend to the next-neighbor Fe atom whereby establishing a linear orbital combination of Ti-O-Fe. A clear picture of the orbital construction in FeTiO3 will help to elucidate the paths of pressure-induced charge transfer and other physical or magnetic characteristics.

The Effect Of Polarization And Ingan Quantum Well Shape In Multiple Quantum Well Light Emitting Diode Heterostructures, Patrick M. Mcbride

Master's Theses

Previous research in InGaN/GaN light emitting diodes (LEDs) employing semi-classical drift-diffusion models has used reduced polarization constants without much physical explanantion. This paper investigates possible physical explanations for this effective polarization reduction in InGaN LEDs through the use of the simulation software SiLENSe. One major problem of current LED simulations is the assumption of perfectly discrete transitions between the quantum well (QW) and blocking layers when experiments have shown this to not be the case. The In concentration profile within InGaN multiple quantum well (MQW) devices shows much smoother and delayed transitions indicative of indium diffusion and drift during …

Networks - Ii: Em-Wave Consideration Through Polarization And Magnetization Effects In Fiber Optics, Hassan Ali, Zain -Ul- Abiden, M. Rizwan Anjum

International Conference on Information and Communication Technologies

Optical fiber communication is the field of the applied science and a promising technique that permits the communication of data in the form of audio and video signal over transparent medium with high data rate over longer distances. Due to the property of fiber optics that it carries high frequency and allows high bandwidth, as the information travels through fiber optic cable in the form of light which belongs to the spectrum of EM wave. The intensity of the electromagnetic radiation decreases in the non conducting medium due to the scattering and absorption of photons. The research on the behavior …

Far-Field Optical Nanoscopy Based On Continuous Wave Laser Stimulated Emission Depletion, C. Kuang, Wei Zhao, Guiren Wang

Faculty Publications

Stimulated emission depletion (STED) microscopy is one of the breakthrough technologies that belong to far-field optical microscopy and can achieve nanoscale spatial resolution. We demonstrate a far-field optical nanoscopy based on continuous wave lasers with different wavelengths, i.e., violet and green lasers for excitation and STED, respectively. Fluorescent dyes Coumarin 102 and Atto 390 are used for validating the depletion efficiency. Fluorescent nanoparticles are selected for characterizing the spatial resolution of the STED system. Linear scanning of the laser beams of the STED system along one line of a microscope slide, which is coated with the nanoparticles, indicates that a …

Near-Field Optical Interactions And Applications, David Haefner

Electronic Theses and Dissertations

The propagation symmetry of electromagnetic fields is affected by encounters with material systems. The effects of such interactions, for example, modifications of intensity, phase, polarization, angular spectrum, frequency, etc. can be used to obtain information about the material system. However, the propagation of electromagnetic waves imposes a fundamental limit to the length scales over which the material properties can be observed. In the realm of near-field optics, this limitation is overcome only through a secondary interaction that couples the high-spatial-frequency (but non-propagating) field components to propagating waves that can be detected. The available information depends intrinsically on this secondary interaction, …

Insulation Condition Assessment Of Power Transformers Using Accelerated Ageing Tests, Mohammad Mirzaie, Ahmad Gholami, Hamid Reza Tayebi

Turkish Journal of Electrical Engineering and Computer Sciences

Thermal stress due to losses and environment temperature causes degradation to paper/oil insulation systems in transformers, even at operating temperature. Experience indicates that thermal ageing of oil and paper in power transformers leads to the change of some insulation characteristics. In this paper, insulating papers immersed in oil have been acceleratory aged at 140, 150, and 160 °C under laboratory conditions. Some of the oil properties, such as water content, breakdown voltage, acidity, together with the aged insulating paper properties such as electric strength, dielectric dissipation factor and tensile strength were measured and analyzed. Also, insulation system conditions under thermal …

Effects Of Polarization And Coherence On The Propagation And The Detection Of Stochastic Electromagnetic Beams, Mohamed Fouad Salem

Electronic Theses and Dissertations

Most of the physically realizable optical sources are radiating in a random manner given the random nature of the radiation of a large number of atoms that constitute the source. Besides, a lot of natural and synthetic materials are fluctuating randomly. Hence, the optical fields that one encounters, in most of the applications are fluctuating and must be treated using random or stochastic functions. Within the framework of the scalar-coherence theory, one can describe changes of the properties of any stochastic field such as the spectral density and the spectral degree of coherence on propagation in any linear medium, deterministic …

Room Temperature Magnetic-Field Manipulation Of Electrical Polarization In Multiferroic Thin Film Composite Bifeo3/La2/3ca1/3mno3, Zhenxiang Cheng, Xiaolin Wang

Australian Institute for Innovative Materials - Papers

The electrical polarization in an epitaxially BiFeO₃ film grown on La_2/3Ca_1/3MnO₃/SrTiO₃ is observed to be enhanced greatly by a magnetic field at room temperature. The simultaneous ferromagnetic order and ferroelectric polarization shown by the BiFeO₃ film causes the strong coupling of the magnetic and ferroelectric domains in the BiFeO₃ films. It was proposed that the activation energy for the electrical polarization domains switching is reduced by the application of a magnetic field. As a result, the electrical polarization that can be switched by an electrical field is increased by the …

Study On Composite Organic Inhibitor Of Zinc Electrode In Alkaline Solutions, Xue-Tao Bu, Guang-Chuan Liang, Cui Li

Journal of Electrochemistry

The synergetic influence of sodium dodecyl benzene sulfonate(SDBS) with Tween-20(Tween) on zinc electrode was studied by polarization experiment,surface tension test,discharge test and SEM.It is found that the composite inhibitor ST has a much higher efficiency.The addition of Tween reduced the critical micell concentration of SDBS on zinc electrode remarkably and the distribution of adsorption became more homogeneous.ST inhibits corrosion of zinc electrode and improves discharge capacity of the whole battery.Through electrochemical morphological observation of anodic passivation behaviors of zinc electrode,the absorption of ST on electrode surface makes discharged production much smaller and keeps crude porous structure intact.Passivation of zinc electrode …

Probing Random Media With Singular Waves, Chaim Schwartz

Electronic Theses and Dissertations

In recent years a resurgence of interest in wave singularities (of which optical vortices are a prominent example), light angular momentum and the relations between them has occurred. Many applications in various areas of linear and non-linear optics have been based on studying effects related to angular momentum and optical vortices. This dissertation examines the use of such wave singularities for studying the light propagation in highly inhomogeneous media and the relationship to angular momentum transfer. Angular momentum carried by light can be, in many cases, divided in two terms. The first one relates to the polarization of light and …

An Electrochemical Study Of Electroless Copper Plating Using Glyoxylic Acid As Reducing Agent, Li-Qiong Wu, Fang-Zu Yang

Journal of Electrochemistry

The electroless copper plating using glyoxylic acid as a reducing agent,Na_(2)EDTA as a chelating agent and K_(4)Fe(CN)_(6) and 2,2'-dipyridyl as additives was studied.The effect of chelating agent and addtives on the polangation behaviovs of copper reduction and glyoxylie acid oxidation were analyzed by linear sweep voltammetry.The results mainly demonstrated that the chelating agent hindered both the oxidation of glyoxylic acid and the reduction of copper complexing ions.It has revealed that K_(4)Fe(CN)_(6)and 2,2'-dipyridyl(with the content over than 20 mg/L)both played negative actions on the oxidation of glyoxylic acid.