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Synchrotron X-Ray Measurement Techniques For Thermal Barrier Coated Cylindrical Samples Under Thermal Gradients, Sanna F. Siddiqui, Kevin Knipe, Albert Manero, Carla Meid, Janine Wischek, John Okasinski, Jonathan Almer, Anette M. Karlsson, Marion Bartsch, Seetha Raghavan
Synchrotron X-Ray Measurement Techniques For Thermal Barrier Coated Cylindrical Samples Under Thermal Gradients, Sanna F. Siddiqui, Kevin Knipe, Albert Manero, Carla Meid, Janine Wischek, John Okasinski, Jonathan Almer, Anette M. Karlsson, Marion Bartsch, Seetha Raghavan
Faculty Bibliography 2010s
Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays. Multiple approaches for beam penetration including collection, tangential, and normal to the layers, along …
Impact Of Charge Impurities On Transport Properties Of Graphene Nanoribbons, Christian W. Smith, Jyoti Katoch, Masa Ishigami
Impact Of Charge Impurities On Transport Properties Of Graphene Nanoribbons, Christian W. Smith, Jyoti Katoch, Masa Ishigami
Faculty Bibliography 2010s
Previous experimental studies have shown qualitative dependence of transport property of graphene nanoribbons on external charged impurities. We have measured transport properties of a graphene nanoribbon at increasing coverage of charged impurities in an ultra high vacuum environment. We discovered an exact relationship between the source-drain and gate gaps at increasing charged impurity density. In addition, we found that graphene nanoribbons have different electronic screening as compared to bulk graphene. Our study paves the way for controlling transport property of nanoribbons using extrinsic impurities.
Growth Of High Quality Zno Thin Films With A Homonucleation On Sapphire, Ming Wei, Ryan Casey Boutwell, Nikolai Faleev, Andrei Osinsky, Winston V. Schoenfeld
Growth Of High Quality Zno Thin Films With A Homonucleation On Sapphire, Ming Wei, Ryan Casey Boutwell, Nikolai Faleev, Andrei Osinsky, Winston V. Schoenfeld
Faculty Bibliography 2010s
ZnO thin films were epitaxially grown on c-plane sapphire substrates by plasma-assisted molecular beam epitaxy. A low temperature homonucleation ZnO layer was found crucial at the interfacial region to absorb the defects formed by the lattice mismatch between the sapphire and ZnO, resulting in a smooth surface that enables smooth 2D epitaxial growth. High quality ZnO films were achieved after careful optimization of critical growth conditions: the sequence of Zn and O source shutters, growth temperature for both the ZnO nucleation and growth layer, and Zn/O ratio. Oxygen plasma pretreatment was not applied prior to the growth, thus shortening the …
Droplet Deformation And Manipulation In An Electrified Microfluidic Channel, Jonathan D. Wehking, Larry Chew, Ranganathan Kumar
Droplet Deformation And Manipulation In An Electrified Microfluidic Channel, Jonathan D. Wehking, Larry Chew, Ranganathan Kumar
Faculty Bibliography 2010s
This letter studies electrically induced droplet deformation to predictably pin and route droplets in a T-junction microchannel. Droplets of various sizes are shown to deform differently and respond to steep electric potential gradients. The relative magnitudes of inertial and electric forces are responsible for droplet deceleration and pinning, and may be manipulated to route a droplet in either direction of a T-junction.
Adsorption Of Silicon On Au(110): An Ordered Two Dimensional Surface Alloy, Hanna Enriquez, Andrew Mayne, Abdelkader Kara, Sébastien Vizzini, Silvan Roth, Boubekeur Lalmi, Ari P. Seitsonen, Bernard Aufray, Thomas Greber, Rachid Belkhou, Gérald Dujardin, Hamid Oughaddou
Adsorption Of Silicon On Au(110): An Ordered Two Dimensional Surface Alloy, Hanna Enriquez, Andrew Mayne, Abdelkader Kara, Sébastien Vizzini, Silvan Roth, Boubekeur Lalmi, Ari P. Seitsonen, Bernard Aufray, Thomas Greber, Rachid Belkhou, Gérald Dujardin, Hamid Oughaddou
Faculty Bibliography 2010s
We report on experimental evidence for the formation of a two dimensional Si/Au(110) surface alloy. In this study, we have used a combination of scanning tunneling microscopy, low energy electron diffraction, Auger electron spectroscopy, and ab initio calculations based on density functional theory. A highly ordered and stable Si-Au surface alloy is observed subsequent to growth of a sub-monolayer of silicon on an Au(110) substrate kept above the eutectic temperature.
Formation Of An Amorphous Phase And Its Crystallization In The Immiscible Nb-Zr System By Mechanical Alloying, N. Al-Aqeeli, C. Suryananrayana, M. A. Hussein
Formation Of An Amorphous Phase And Its Crystallization In The Immiscible Nb-Zr System By Mechanical Alloying, N. Al-Aqeeli, C. Suryananrayana, M. A. Hussein
Faculty Bibliography 2010s
Mechanical alloying of binary Nb-Zr powder mixtures was carried out to evaluate the formation of metastable phases in this immiscible system. The milled powders were characterized for their constitution and structure by X-ray diffraction and transmission electron microscopy methods. It was shown that an amorphous phase had formed on milling the binary powder mixture for about 10 h and that it had crystallized on subsequent milling up to 50-70 h, referred to as mechanical crystallization. Thermodynamic and structural arguments have been presented to explain the formation of the amorphous phase and its subsequent crystallization.
Response To "Comment On 'Confined Propagation And Near Single-Mode Laser Oscillation In A Gain-Guided, Index Antiguided Optical Fiber'" Appl. Phys. Lett. 102, 026101 (2013), Michael Bass, Martin C. Richardson, John Ballato
Response To "Comment On 'Confined Propagation And Near Single-Mode Laser Oscillation In A Gain-Guided, Index Antiguided Optical Fiber'" Appl. Phys. Lett. 102, 026101 (2013), Michael Bass, Martin C. Richardson, John Ballato
Faculty Bibliography 2010s
No abstract provided.
Insight Into Morphology Changes Of Nanoparticle Laden Droplets In Acoustic Field, Saptarshi Basu, Erick Tijerino, Ranganathan Kumar
Insight Into Morphology Changes Of Nanoparticle Laden Droplets In Acoustic Field, Saptarshi Basu, Erick Tijerino, Ranganathan Kumar
Faculty Bibliography 2010s
Hollow structures with unique morphologies form due to particle agglomeration in acoustically levitated nanofluid functional droplets when subjected to external heating. The final diameter of the structure depends only on the ratio of agglomeration to evaporation time scales for various nanoparticle laden droplets, and not on the type of the suspended particles. These time scales depend only on nanoparticle concentration. This valuable information may be exploited to form microstructures with desired properties from ceramic compounds. Phase diagrams for alumina and silica droplets indicate the transition from a bowl to ring structure depending on concentration.
The Effect Of Oxygen Flow Rate And Radio Frequency Plasma Power On Cubic Znmgo Ultraviolet Sensors Grown By Plasma-Enhanced Molecular Beam Epitaxy, R. Casey Boutwell, Ming Wei, Winston V. Schoenfeld
The Effect Of Oxygen Flow Rate And Radio Frequency Plasma Power On Cubic Znmgo Ultraviolet Sensors Grown By Plasma-Enhanced Molecular Beam Epitaxy, R. Casey Boutwell, Ming Wei, Winston V. Schoenfeld
Faculty Bibliography 2010s
Cubic Zn1-xMgxO thin films were produced by Plasma-Enhanced Molecular Beam Epitaxy. Oxygen flow rate and applied Radio-Frequency (RF) plasma power were varied to investigate the impact on film growth and optoelectronic device performance. Solar-blind and visible-blind detectors were fabricated with metal-semiconductor-metal interdigitated Ni/Mg/Au contacts and responsivity is compared under different growth conditions. Increasing oxygen flow rate and RF plasma power increased Zn incorporation in the film, which leads to phase segregation at relatively high Zn/Mg ratio. Responsivity as high as 61 A/W was measured in phase-segregated ZnMgO visible-blind detectors.
Simultaneous Optical And Photoacoustic Measurement Of Nonlinear Absorption, Panit Chantharasupawong, Reji Philip, Jayan Thomas
Simultaneous Optical And Photoacoustic Measurement Of Nonlinear Absorption, Panit Chantharasupawong, Reji Philip, Jayan Thomas
Faculty Bibliography 2010s
A measurement technique to perform optical Z-scan and photoacoustic Z-scan simultaneously called OPAZ-scan is demonstrated. It is found that the simultaneous measurement of the optical and photoacoustic Z-scan signals provides substantially better insight into the mechanism of optical nonlinearity. The system is able to identify mixed nonlinear processes within a mixture of nonlinear scattering species and nonlinear absorbers.
A Low Voltage And Submillisecond-Response Polymer-Stabilized Blue Phase Liquid Crystal, Yuan Chen, Daming Xu, Shin-Tson Wu, Shin-Ichi Yamamoto, Yashuhiro Haseba
A Low Voltage And Submillisecond-Response Polymer-Stabilized Blue Phase Liquid Crystal, Yuan Chen, Daming Xu, Shin-Tson Wu, Shin-Ichi Yamamoto, Yashuhiro Haseba
Faculty Bibliography 2010s
We report a polymer-stabilized blue phase liquid crystal (BPLC) whose Kerr constant is about 2.2x larger than previous record. When filled in a 3.2-mu m-thick vertical field switching cell, the on-state voltage is merely 8.4 V (at lambda = 514 nm) while keeping submillisecond response time and negligible hysteresis ( < 1%) at the room temperature. These results imply that the dawn of BPLC era for high speed display and photonic devices has finally arrived.
On Electric Conduction Of Amorphous Silicon Carbonitride Derived From A Polymeric Precursor, Yaohan Chen, Fuqian Yang, Linan An
On Electric Conduction Of Amorphous Silicon Carbonitride Derived From A Polymeric Precursor, Yaohan Chen, Fuqian Yang, Linan An
Faculty Bibliography 2010s
A long-existing problem that the conductivity of amorphous silicon carbonitrides derived from polymeric precursor increases significantly with pyrolysis temperature is investigated. We show that the conductivity exhibited an Arrhenius dependence on pyrolysis temperature, with the activation energy of similar to 3.41 eV. Structural analysis using Raman spectroscopy reveals that the free carbon within the material undergoes a sp(3)-to-sp(2) transition as pyrolysis temperature increases, with the activation energy of similar to 3.6 eV. We conclude that the pyrolysis-temperature induced increase in the conductivity is mainly due to the increase in the conductivity of the free carbon. A simple model is proposed …
Electric Field-Induced Monodomain Blue Phase Liquid Crystals, Yuan Chen, Shin-Tson Wu
Electric Field-Induced Monodomain Blue Phase Liquid Crystals, Yuan Chen, Shin-Tson Wu
Faculty Bibliography 2010s
We demonstrate an electric field-induced monodomain blue phase liquid crystal and its application for polarizer-free reflective displays. Superior to multidomain structure, the monodomain exhibits a relatively high reflectance and narrow bandwidth (similar to 25 nm) so the reflected colors look vivid. As the applied voltage increases, the double-twist structure is gradually unwound so that Bragg reflection decreases leading to analogous grayscale. The submillisecond response time enables this reflective display to play videos without image blurs. Such a monodomain blue phase selectively reflects right-handed circularly polarized light when the employed chiral dopant is right-handed, and the reflected light is nearly circularly …
High-Contrast, All-Silicon Waveguiding Platform For Ultra-Broadband Mid-Infrared Photonics, Jeff Chiles, Saeed Khan, Jichi Ma, Sasan Fathpour
High-Contrast, All-Silicon Waveguiding Platform For Ultra-Broadband Mid-Infrared Photonics, Jeff Chiles, Saeed Khan, Jichi Ma, Sasan Fathpour
Faculty Bibliography 2010s
Suspended silicon-membrane ridge waveguides are fabricated and characterized on a single-material photonic device platform. By using direct bonding, a thin layer of silicon is fused to a bulk silicon substrate, which is patterned with narrow trenches. Waveguides are etched on the resulting suspended membranes and are characterized at mid-and near-infrared wavelengths. Transverse magnetic-mode propagation losses of 2.8 +/- 0.5 and 5.6 +/- 0.3 dB/cm at 3.39 and 1.53 mu m wavelengths are measured, respectively. This all-silicon optical platform is capable of continuous low-loss waveguiding from wavelengths of 1.2-8.5 mu m, enabling numerous applications in frequency conversion and spectral analysis.
Hidden Symmetry Subgroup Problems, Thomas Decker, Gábor Ivanyos, Miklos Santha, University Of Central Florida
Hidden Symmetry Subgroup Problems, Thomas Decker, Gábor Ivanyos, Miklos Santha, University Of Central Florida
Faculty Bibliography 2010s
We advocate a new approach for addressing hidden structure problems and finding efficient quantum algorithms. We introduce and investigate the hidden symmetry subgroup problem (HSSP), which is a generalization of the well-studied hidden subgroup problem (HSP). Given a group acting on a set and an oracle whose level sets define a partition of the set, the task is to recover the subgroup of symmetries of this partition inside the group. The HSSP provides a unifying framework that, besides the HSP, encompasses a wide range of algebraic oracle problems, including quadratic hidden polynomial problems. While the HSSP can have provably exponential …
On-Chip Non-Reciprocal Optical Devices Based On Quantum Inspired Photonic Lattices, R. El-Ganainy, A. Eisfeld, Miguel Levy, D. N. Christodoulides
On-Chip Non-Reciprocal Optical Devices Based On Quantum Inspired Photonic Lattices, R. El-Ganainy, A. Eisfeld, Miguel Levy, D. N. Christodoulides
Faculty Bibliography 2010s
We propose integrated optical structures that can be used as isolators and polarization splitters based on engineered photonic lattices. Starting from optical waveguide arrays that mimic Fock space (quantum state with a well-defined particle number) representation of a non-interacting two-site Bose Hubbard Hamiltonian, we show that introducing magneto-optic nonreciprocity to these structures leads to a superior optical isolation performance. In the forward propagation direction, an input TM polarized beam experiences a perfect state transfer between the input and output waveguide channels while surface Bloch oscillations block the backward transmission between the same ports. Our analysis indicates a large isolation ratio …
Millimeter-Wave Photoresponse Due To Excitation Of Two-Dimensional Plasmons In Ingaas/Inp High-Electron-Mobility Transistors, N. Nader Esfahani, R. E. Peale, W. R. Buchwald, C. J. Fredricksen, J. R. Hendrickson, J. W. Cleary
Millimeter-Wave Photoresponse Due To Excitation Of Two-Dimensional Plasmons In Ingaas/Inp High-Electron-Mobility Transistors, N. Nader Esfahani, R. E. Peale, W. R. Buchwald, C. J. Fredricksen, J. R. Hendrickson, J. W. Cleary
Faculty Bibliography 2010s
A polarized photoresponse to mm-wave radiation over the frequency range of 40 to 108 GHz is demonstrated in a grating-gated high electron mobility transistor (HEMT) formed by an InGaAs/InP heterostructure. The photoresponse is observed within the plasmon resonance absorption band of the HEMT, whose gate consists of a 9 mu m period grating that couples incident radiation to plasmons in the 2D electron gas. Gate-bias changes the channel carrier concentration, causing a corresponding change in photoresponse in agreement with theoretical expectations for the shift in the plasmon resonance band. The noise equivalent power is estimated to be 235 pW/Hz(1/2).
An Apparatus For Studying Scintillator Properties At High Isostatic Pressures, R. M. Gaumé, S. Lam, M. Gascón, W. Setyawan, S. Curtarolo, R. S. Feigelson
An Apparatus For Studying Scintillator Properties At High Isostatic Pressures, R. M. Gaumé, S. Lam, M. Gascón, W. Setyawan, S. Curtarolo, R. S. Feigelson
Faculty Bibliography 2010s
We describe the design and operation of a unique hydraulic press for the study of scintillator materials under isostatic pressure. This press, capable of developing a pressure of a gigapascal, consists of a large sample chamber pressurized by a two-stage hydraulic amplifier. The optical detection of the scintillation light emitted by the sample is performed, through a large aperture optical port, by a photodetector located outside the pressure vessel. In addition to providing essential pressure-dependent studies on the emission characteristics of radioluminescent materials, this apparatus is being developed to elucidate the mechanisms behind the recently observed dependency of light-yield nonproportionality …
Numerical And Analytical Methods For Variational Inequalities And Related Problems 2013, Zhenyu Huang, Ram N. Mohapatra, Shih-Sen Change, Qingzhi Yang
Numerical And Analytical Methods For Variational Inequalities And Related Problems 2013, Zhenyu Huang, Ram N. Mohapatra, Shih-Sen Change, Qingzhi Yang
Faculty Bibliography 2010s
No abstract provided.
Effects Of Anode Materials On Resistive Characteristics Of Nio Thin Films, Ze Jia, Linkai Wang, Naiwen Zhang, Tianling Ren, Juin J. Liou
Effects Of Anode Materials On Resistive Characteristics Of Nio Thin Films, Ze Jia, Linkai Wang, Naiwen Zhang, Tianling Ren, Juin J. Liou
Faculty Bibliography 2010s
This letter shows that the NiO-based structure with different anodes has different resistive switching properties. A conical conductive filament (CF) model is proposed for oxygen vacancies distributed in NiO films. Modeling analysis reveals much larger dissolution velocity of CF near anodes than near cathodes during the reset process. Different interfaces shown in Auger electron spectroscopy can be bound with the model to reveal that CF is dissolved in the structure with Pt or Au as anodes, while CF remains constant if the anode material is Ti or Al, which can explain whether switching properties occur in the specific NiO-based structures.
Ultrahigh Vacuum-Compatible Sockets For Pin Grid Arrays Used In Nanoscale And Atomic Physics, Jyoti Katock, Cameron Glasscock, Masa Ishigami
Ultrahigh Vacuum-Compatible Sockets For Pin Grid Arrays Used In Nanoscale And Atomic Physics, Jyoti Katock, Cameron Glasscock, Masa Ishigami
Faculty Bibliography 2010s
Pin grid arrays are often used for packaging devices for nanoscale and atomic physics experiments performed in ultrahigh vacuum (UHV). These arrays require their complementary socket arrays for measurements, yet UHV-compatible sockets are not commercially available. In this paper, the authors describe the design and construction of fully UHV-compatible sockets, which provide reliable electronic contact down to cryogenic temperatures and survive repeated insertion-retraction cycles.
Silicon-On-Nitride Waveguides For Mid- And Near-Infrared Integrated Photonics, Saeed Khan, Jeff Chiles, Jichi Ma, Sasan Fathpour
Silicon-On-Nitride Waveguides For Mid- And Near-Infrared Integrated Photonics, Saeed Khan, Jeff Chiles, Jichi Ma, Sasan Fathpour
Faculty Bibliography 2010s
Silicon-on-nitride ridge waveguides are demonstrated and characterized at mid-and near-infrared optical wavelengths. Silicon-on-nitride thin films were achieved by bonding a silicon handling die to a silicon-on-insulator die coated with a low-stress silicon nitride layer. Subsequent removal of the silicon-on-insulator substrate results in a thin film of silicon on a nitride bottom cladding, readily available for waveguide fabrication. At the mid-infrared wavelength of 3.39 mu m, the fabricated waveguides have a propagation loss of 5.2 +/- 0.6 dB/cm and 5.1 +/- 0.6 dB/cm for the transverse-electric and transverse-magnetic modes, respectively.
On A Calderon Problem In Frequency Differential Electrical Impedance Tomography, Sungwhan Kim, Alexandru Tamasan
On A Calderon Problem In Frequency Differential Electrical Impedance Tomography, Sungwhan Kim, Alexandru Tamasan
Faculty Bibliography 2010s
Recent research in electrical impedance tomography produced images of biological tissue from frequency differential boundary voltages and corresponding currents. Physically one is to recover the electrical conductivity sigma and permittivity c from the frequency differential boundary data. Let gamma = sigma+iota omega is an element of denote the complex admittivity, Lambda(gamma) be the corresponding Dirichlet-to-Neumann map, and d Lambda(gamma)/d omega|omega=0 be its frequency differential at omega = 0. If sigma is an element of C-1,C-1 ((Omega) over bar) is constant near the boundary and is an element of is an element of C-0(1,1) (Omega), we show that d Lambda(gamma)/d omega|omega=0 …
Wireless Passive Polymer-Derived Sicn Ceramic Sensor With Integrated Resonator/Antenna, Yan Li, Yuxi Yu, Haisheng San, Yansong Wang, Linan An
Wireless Passive Polymer-Derived Sicn Ceramic Sensor With Integrated Resonator/Antenna, Yan Li, Yuxi Yu, Haisheng San, Yansong Wang, Linan An
Faculty Bibliography 2010s
This paper presents a passive wireless polymer-derived silicon carbonitride (SiCN) ceramic sensor based on cavity radio frequency resonator together with integrated slot antenna. The effect of the cavity sensor dimensions on the Q-factor and resonant frequency is investigated by numerical simulation. A sensor with optimal dimensions is designed and fabricated. It is demonstrated that the sensor signal can be wirelessly detected at distances up to 20 mm. Given the high-temperature stability of the SiCN, the sensor is very promising for high-temperature wireless sensing applications.
Semiconductor Laser Monolithically Pumped With A Light Emitting Diode Operating In The Thermoelectrophotonic Regime, X. Liu, G. Zhao, Y. Zhang, D. G. Deppe
Semiconductor Laser Monolithically Pumped With A Light Emitting Diode Operating In The Thermoelectrophotonic Regime, X. Liu, G. Zhao, Y. Zhang, D. G. Deppe
Faculty Bibliography 2010s
Data are presented on a monolithic chip that integrates a quantum well semiconductor laser with a high efficiency light emitting diode (LED), with the LED used to optically pump the laser. The LED operates in the thermoelectrophotonic regime that can produce heat absorption, offering the possibility of heat pump action. The internal optical pumping also offers the possibility of very low internal loss in the laser and the prospect of reaching greater than unity power conversion efficiency in the laser chip. The integrated laser chip is operated and tested under continuous-wave room temperature operation.
Optical Rotatory Power Of Polymer-Stabilized Blue Phase Liquid Crystals, Yifan Liu, Yi-Fen Lan, Hongxia Zhang, Ruidong Zhu, Daming Xu, Cheng-Yeh Tsai, Jen-Kuei Lu, Norio Sugiura, Yu-Chieh Lin, Shin-Tson Wu
Optical Rotatory Power Of Polymer-Stabilized Blue Phase Liquid Crystals, Yifan Liu, Yi-Fen Lan, Hongxia Zhang, Ruidong Zhu, Daming Xu, Cheng-Yeh Tsai, Jen-Kuei Lu, Norio Sugiura, Yu-Chieh Lin, Shin-Tson Wu
Faculty Bibliography 2010s
Macroscopically, a polymer-stabilized blue phase liquid crystal (BPLC) is assumed to be an optically isotropic medium. Our experiment challenges this assumption. Our results indicate that the optical rotatory power (ORP) of some nano-scale double-twist cylinders in a BPLC composite causes the polarization axis of the transmitted light to rotate a small angle, which in turn leaks through the crossed polarizers. Rotating the analyzer in azimuthal direction to correct this ORP can greatly improve the contrast ratio. A modified De Vries equation based on a thin twisted-nematic layer is proposed to explain the observed phenomena.
Laser-Plasma Source Parameters For Kr, Gd, And Tb Ions At 6.6 Nm, Majid Masnavi, John Szilagyi, Homaira Parchamy, Martin C. Richardson
Laser-Plasma Source Parameters For Kr, Gd, And Tb Ions At 6.6 Nm, Majid Masnavi, John Szilagyi, Homaira Parchamy, Martin C. Richardson
Faculty Bibliography 2010s
There is increasing interest in extreme-ultraviolet (EUV) laser-based lamps for sub-10-nm lithography operating in the region of 6.6 nm. A collisional-radiative model is developed as a post-processor of a hydrodynamic code to investigate emission from resonance lines in Kr, Gd, and Tb ions under conditions typical for mass-limited EUV sources. The analysis reveals that maximum conversion efficiencies of Kr occur at 5 x 10(10) W/cm(2), while for Gd and Tb it was similar or equal to 0.9%/2 pi sr for laser intensities of (2-5) x 10(12) W/cm(2).
Grain Size Softening Effect In Al62.5cu25fe12.5 Nanoquasicrystals, N. K. Mukhopadhyay, F. Ali, S. Scudino, M. Samadi Khoshkhoo, M. Stoica, V. C. Srivastava, V. Uhlenwinkel, G. Vaughan, C. Suryanarayana, J. Eckert
Grain Size Softening Effect In Al62.5cu25fe12.5 Nanoquasicrystals, N. K. Mukhopadhyay, F. Ali, S. Scudino, M. Samadi Khoshkhoo, M. Stoica, V. C. Srivastava, V. Uhlenwinkel, G. Vaughan, C. Suryanarayana, J. Eckert
Faculty Bibliography 2010s
Inverse Hall-Petch (IHP) behavior in nano-quasicrystalline Al62.5Cu25Fe12.5 is reported. Powders with varying grain sizes were produced by mechanical milling of spray-formed quasicrystals. The hardness of the milled powders increased with decreasing grain size down to about 40 nm and decreased with further refinement, demonstrating the IHP behavior. This critical grain size was found to be larger compared to other metallic nanocrystalline alloys. This IHP behaviour has been attributed to the structural complexity in quasicrystals and to thermally activated shearing events of atoms at the grain boundaries.
Quantum Cascade Laser Intracavity Absorption Spectrometer For Trace Gas Sensing, A. V. Muraviev, D. E. Maukonen, C. J. Fredricksen, Gautam Medhi, R. E. Peale
Quantum Cascade Laser Intracavity Absorption Spectrometer For Trace Gas Sensing, A. V. Muraviev, D. E. Maukonen, C. J. Fredricksen, Gautam Medhi, R. E. Peale
Faculty Bibliography 2010s
A mid-infrared intracavity laser absorption spectrometer for trace gas sensing is demonstrated. An external-cavity multi-mode quantum cascade laser with central wavelength 8.0 mu m was combined with a scanning Fabry-Perot interferometer, which analyzed the change of the laser emission spectrum caused by introducing an analyte inside the cavity. The detection mechanism is based on monitoring the laser spectrum dynamics at adiabatically changing laser conditions in long pulse operation mode. Fast acquisition and vapor exchange allow nearly real-time analyte detection. Sensitivity at the level of 1 x 10(-5) cm(-1) was demonstrated based on a weak water vapor absorption line.
Correlation Of Embryonic Skeletal Muscle Myotube Physical Characteristics With Contractile Force Generation On An Atomic Force Microscope-Based Bio-Microelectromechanical Systems Device, K. L. Pirozzi, C. J. Long, C. W. Mcaleer, A. S. T. Smith, J. J. Hickman
Correlation Of Embryonic Skeletal Muscle Myotube Physical Characteristics With Contractile Force Generation On An Atomic Force Microscope-Based Bio-Microelectromechanical Systems Device, K. L. Pirozzi, C. J. Long, C. W. Mcaleer, A. S. T. Smith, J. J. Hickman
Faculty Bibliography 2010s
Rigorous analysis of muscle function in in vitro systems is needed for both acute and chronic biomedical applications. Forces generated by skeletal myotubes on bio-microelectromechanical cantilevers were calculated using a modified version of Stoney's thin-film equation and finite element analysis (FEA), then analyzed for regression to physical parameters. The Stoney's equation results closely matched the more intensive FEA and the force correlated to cross-sectional area (CSA). Normalizing force to measured CSA significantly improved the statistical sensitivity and now allows for close comparison of in vitro data to in vivo measurements for applications in exercise physiology, robotics, and modeling neuromuscular diseases.