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2010

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Articles 1 - 30 of 159

Full-Text Articles in Nanoscience and Nanotechnology

Field Effect And Magnetically Induced Capacitive Tuning In Hole Doped La1-Xsrxmno3, Zsolt Marton Dec 2010

Field Effect And Magnetically Induced Capacitive Tuning In Hole Doped La1-Xsrxmno3, Zsolt Marton

Publicly Accessible Penn Dissertations

Electrostatic modulation of interface conduction between semiconductors and insulating oxides is the foundation of semiconductor technology. This field effect concept can be applied on complex oxides, such as high temperature superconductors and colossal magnetoresistive manganites, in order to create new electronic and magnetic phases. Competition and coexistence of multiple nanoscale phases make them exciting to study around phase transitions. This study on hole doped La1-xSrxMnO3 systems has a two-fold purpose.

One is the demonstration of the field effect on La1-xSrxMnO3 (x = 0.125, 0.2, 0.3, 0.5) thin films. It is an important step towards electrostatic control of ...


Patterning Of Alloy Precipitation Through External Pressure, Jack A. Franklin Dec 2010

Patterning Of Alloy Precipitation Through External Pressure, Jack A. Franklin

Publicly Accessible Penn Dissertations

Due to the nature of their microstructure, alloyed components have the benefit of meeting specific design goals across a wide range of electrical, thermal, and mechanical properties. In general by selecting the correct alloy system and applying a proper heat treatment it is possible to create a metallic sample whose properties achieve a unique set of design requirements. This dissertation presents an innovative processing technique intended to control both the location of formation and the growth rates of precipitates within metallic alloys in order to create multiple patterned areas of unique microstructure within a single sample. Specific experimental results for ...


Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath Dec 2010

Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath

Electronic Theses and Dissertations

Quantum dots are semiconductive particles whose properties are highly influenced by the presence of at least one electron. Cadmium selenide quantum dots were synthesized via colloidal synthesis. Contrary to previous preparations, more focus was placed on the temperature rather than the duration of time at which they form. A series of colored solutions were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra showed that the temperature-dependent quantum dots were successfully synthesized. The quantum dots were also immobilized on various surfaces, and the luminescence properties were examined. The quantum dots that were ...


Universality Of Non-Ohmic Shunt Leakage In Thin-Film Solar Cells, Sourabh Dongaonkar, J. D. Servaites, G. M. Ford, S. Loser, R. M. Gelfand, H. Mohseni, Hugh Hillhouse, R. Agrawal, M. A. Ratner, T. J. Marks, Mark S. Lundstrom, Muhammad A. Alam Dec 2010

Universality Of Non-Ohmic Shunt Leakage In Thin-Film Solar Cells, Sourabh Dongaonkar, J. D. Servaites, G. M. Ford, S. Loser, R. M. Gelfand, H. Mohseni, Hugh Hillhouse, R. Agrawal, M. A. Ratner, T. J. Marks, Mark S. Lundstrom, Muhammad A. Alam

Other Nanotechnology Publications

We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In, Ga)Se-2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V < similar to 0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (I-sh), across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V = 0, (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism. (C) 2010 American Institute of Physics. [doi:10.1063/1.3518509]


Uncertainty Propagation In A Multiscale Model Of Nanocrystalline Plasticity, Marisol Koslowski, Alejandro Strachan Dec 2010

Uncertainty Propagation In A Multiscale Model Of Nanocrystalline Plasticity, Marisol Koslowski, Alejandro Strachan

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

We characterize how uncertainties propagate across spatial and temporal scales in a physicsbased model of nanocrystalline plasticity of fcc metals. Our model combines molecular dynamics (MD) simulations to characterize atomic level processes that govern dislocation basedplastic deformation with a phase field approach to dislocation dynamics (PFDD) that describes how an ensemble of dislocations evolve and interact to determine the mechanical response of the material. We apply this approach to a nanocrystalline Ni specimen of interest in micro-electromechanical (MEMS) switches. Our approach enables us to quantify how internal stresses that result from the fabrication process affect the properties of dislocations (using ...


Energetics And Kinetics Of Dislocation Initiation In The Stressed Volume At Small Scales, Tianlei Li Dec 2010

Energetics And Kinetics Of Dislocation Initiation In The Stressed Volume At Small Scales, Tianlei Li

Doctoral Dissertations

Instrumented nanoindentation techniques have been widely used in characterizing mechanical behavior of materials in small length scales. For defect-free single crystals under nanoindentation, the onset of elastic-plastic transition is often shown by a sudden displacement burst in the measured load-displacement curve. It is believed to result from the homogeneous dislocation nucleation because the maximum shear stress at the pop-in load approaches the theoretical strength of the material and because statistical measurements agree with a thermally activated process of homogeneous dislocation nucleation. For single crystals with defects, the pop-in is believed to result from the sudden motion of pre-existing dislocations or ...


Generalized Ellipsometry On Sculptured Thin Films Made By Glancing Angle Deposition, Daniel Schmidt Dec 2010

Generalized Ellipsometry On Sculptured Thin Films Made By Glancing Angle Deposition, Daniel Schmidt

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

In this thesis, physical properties of highly optically and magnetically anisotropic metal sculptured thin films made by glancing angle deposition are presented. Predominantly, the determination of optical and magneto-optical properties with spectroscopic generalized Mueller matrix ellipsometry and homogenization approaches is discussed. Nomenclatures are proposed to unambiguously identify the sculptured thin film geometry.

Generalized ellipsometry, a non-destructive optical characterization technique, is employed to determine geometrical structure and anisotropic dielectric properties of highly spatially coherent three-dimensionally nanostructured thin films in the spectral range from 400 to 1700 nm. The analysis of metal slanted columnar thin films (F1-STFs) deposited at glancing angle (θ ...


Molecular Physics Of Electrical Double Layers In Electrochemical Capacitors, Guang Feng Dec 2010

Molecular Physics Of Electrical Double Layers In Electrochemical Capacitors, Guang Feng

All Dissertations

At present, electrochemical capacitors (ECs) are emerging as a novel type of energy storage devices and have attracted remarkable attention, due to their key characteristics, such as high power density and excellent durability. However, the moderate energy density of ECs restricts their widespread deployment in everyday technology. To surmount this limitation, four strategies are adopted: (1) to reduce the total system mass, (2) to increase the specific surface area of electrodes, (3) to enhance normalized capacitance, and (4) to expand the range of potentials applied on electrodes. The implementation of these approaches critically relies on the fundamental understanding of physical ...


Synthesis, Stabilization, And Characterization Of Metal Nanoparticles, Gregory White Ii Dec 2010

Synthesis, Stabilization, And Characterization Of Metal Nanoparticles, Gregory White Ii

All Dissertations

Wet chemical synthesis techniques offer the ability to control various nanoparticle characteristics including size, shape, dispersibility in both aqueous and organic solvents, and tailored surface chemistries appropriate for different applications. Large quantities of stabilizing ligands or surfactants are often required during synthesis to achieve these nanoparticle characteristics. Unfortunately, excess reaction byproducts, surfactants, and ligands remaining in solution after nanoparticle synthesis can impede application, and therefore post-synthesis purification must be employed. A liquid-liquid solvent/anti-solvent pair (typically ethanol/toluene or ethanol/hexane for gold nanoparticles, GNPs) can be used to both purify and size-selectively fractionate hydrophobically modified nanoparticles. Alternatively, carbon dioxide ...


Small-Scale Solutions To Grand Challenges In Thermal Management, Suresh V. Garimella Nov 2010

Small-Scale Solutions To Grand Challenges In Thermal Management, Suresh V. Garimella

Birck and NCN Publications

Research needs in the field of thermal management of microelectronics and microsystems are identified, followed by a brief discussion of recent advances in solution approaches. These include novel solutions that rely on two-phase flow at the microscale, micropumps, droplet actuation on structured surfaces, passive transport in wick structures, ion-driven and piezoelectrically driven airflow, nanostructured thermal materials, and novel diagnostic tools.


Microbiorobots For Single Cell Manipulation, Mahmut Selman Sakar Nov 2010

Microbiorobots For Single Cell Manipulation, Mahmut Selman Sakar

Publicly Accessible Penn Dissertations

One of the great challenges in nano and micro scale science and engineering is the independent manipulation of biological cells and small man-made objects with active sensing. For such biomedical applications as single cell manipulation, telemetry, and localized targeted delivery of chemicals, it is important to fabricate microstructures that can be powered and controlled without a tether in fluidic environments. These microstructures can be used to develop microrobots that have the potential to make existing therapeutic and diagnostic procedures less invasive.

Actuation can be realized using various different organic and inorganic methods. Previous studies explored different forms of actuation and ...


Closing The Gap Between The Industry And Higher Education Institutions- Case Examples From East African Region, Deogratias Harorimana Mr Nov 2010

Closing The Gap Between The Industry And Higher Education Institutions- Case Examples From East African Region, Deogratias Harorimana Mr

Dr Deogratias Harorimana

Much complained about is the quality of graduates Universities put on the labour market. Less talked about however is why knowledge institutions seems to be bad knowledge managers. In this presentation I argue that DIRECT collaborative relationship between Industry,Governments and Higher Education Institutions is a per-requisite.Good relationship is key to building such a successful knowledge transfer strategies between Industries and Educational and Research Institutions. This paper explores what makes a good Knowledge Transfer Partnership Strategy and highlights some key lessons for businesses, Universities and Government bodies. This paper was a Key note presentation to the Annual International Conference ...


Synthesis Of Mild–Hard Aao Templates For Studying Magnetic Interactions Between Metal Nanowires, Jin-Hee Lim, Aurelian Rotaru, Seong-Gi Min, Leszek Malkinski, John B. Wiley Nov 2010

Synthesis Of Mild–Hard Aao Templates For Studying Magnetic Interactions Between Metal Nanowires, Jin-Hee Lim, Aurelian Rotaru, Seong-Gi Min, Leszek Malkinski, John B. Wiley

Physics Faculty Publications

The sequential application of mild and hard anodization techniques in the fabrication of porous aluminamembranes allows one to decrease the number of continuous pores in anodized aluminium oxide (AAO) templates. Initially, standard mild anodization techniques were used to create porous templates with 100 nm interpore distances and 70 nm pore diameters. Hard anodization treatment on the same membrane then produced interpore distances of about 265 nm with diameters of 110 nm. At the interface between the two anodization steps, many of the mild-side pores were terminated to create a mild–hard membrane (Mi–Ha AAO) where the functional interpore distances ...


Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew Nov 2010

Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew

Heather Clark

Second harmonic generation (SHG) has been developed in our laboratories as a high-resolution nonlinear optical imaging microscopy for cellular membranes and intact tissues. SHG shares many of the advantageous features for microscopy of another more established nonlinear optical technique: two-photon excited fluorescence (TPEF). Both are capable of optical sectioning to produce threedimensional images of thick specimens and both result in less photodamage to living tissue than confocal microscopy. SHG is complementary to TPEF in that it uses a different contrast mechanism and is most easily detected in the transmitted light optical path. It can be used to image membrane probes ...


A Comparative Study Of Optical Fluorescent Nanosensors ("Pebbles") And Fiber Optic Microsensors For Oxygen Sensing, Z. Chen-Esterlit, S. F. Peteu, Heather Clark, W. Mcdonald, R. Kopelman Nov 2010

A Comparative Study Of Optical Fluorescent Nanosensors ("Pebbles") And Fiber Optic Microsensors For Oxygen Sensing, Z. Chen-Esterlit, S. F. Peteu, Heather Clark, W. Mcdonald, R. Kopelman

Heather Clark

In this paper we report the use of phase sensitive fluorometry to obtain preliminary results from opto-chemical fluorescent oxygen nanosensors. PEBBLE (Probe Encapsulated By Biologically Localized Embedding) sensors were fabricated by immobilizing tris(4,7-diphenyl—1, 10-phenanthroline)Ru(II) chloride and tris(1,10-phenanthroline)Ru(II) chloride within a polyacrylamide matrix. PEBBLEs have diameters of 20-200 nm and exhibit excellent performance for dissolved oxygen detection. Their performance is compared with micrometer-sized (10-20 μm) optical fiber sensors and free dye in solution. Oxygen sensing ability of PEBBLEs was tested in the presence of other quenchers and compared with free dyes in ...


Sub-Wavelength Plasmonic Readout For Direct Linear Analysis Of Optically Tagged Dna, Jonathan Varsanik, William Teynor, John Leblanc, Heather Clark, Jeffrey Krogmeier, Tian Yang, Jonathan Bernstein Nov 2010

Sub-Wavelength Plasmonic Readout For Direct Linear Analysis Of Optically Tagged Dna, Jonathan Varsanik, William Teynor, John Leblanc, Heather Clark, Jeffrey Krogmeier, Tian Yang, Jonathan Bernstein

Heather Clark

This work describes the development and fabrication of a novel nanofluidic flow-through sensing chip that utilizes a plasmonic resonator to excite fluorescent tags with sub-wavelength resolution. We cover the design of the microfluidic chip and simulation of the plasmonic resonator using Finite Difference Time Domain (FDTD) software. The fabrication methods are presented, with testing procedures and preliminary results. This research is aimed at improving the resolution limits of the Direct Linear Analysis (DLA) technique developed by US Genomics. In DLA, intercalating dyes which tag a specific 8 base-pair sequence are inserted in a DNA sample. This sample is pumped though ...


Determining The Electronic Properties Of Individual Nanointerfaces By Combining Intermittent Afm Imaging And Contact Spectroscopy, Ramsey A. Kraya, Dawn A. Bonnell Nov 2010

Determining The Electronic Properties Of Individual Nanointerfaces By Combining Intermittent Afm Imaging And Contact Spectroscopy, Ramsey A. Kraya, Dawn A. Bonnell

Departmental Papers (MSE)

A method to determine the electronic properties at nanointerfaces or of nanostructures by utilizing intermittent contact atomic force microscopy and contact spectroscopy in one system is developed. By combining these two methods, the integrity of the interface or structure is maintained during imaging, while the extraction of the electronic information is obtained with contact spectroscopy. This method is especially vital for understanding interfaces between metal nanoparticles and substrates, where the nanoparticles are not tethered to the surface and can be combined with new and evolving techniques of thermal drift compensation to allow for a larger range of experiments on nanointerfaces ...


Atomic Force Microscopy For Better Probing Surface Properties At Nanoscale: Calibration, Design And Application, Yu Liu Oct 2010

Atomic Force Microscopy For Better Probing Surface Properties At Nanoscale: Calibration, Design And Application, Yu Liu

Electronic Thesis and Dissertation Repository

To measure force by AFM with high resolution requires accurate calibration of optic – lever detection sensitivity and spring constant. On biological AFM force mode, the coupling effects of the liquid environment, spot size of laser beam and laser spot location on AFM cantilever backside, must be considered to correlate the static sensitivities from force curves in air and in liquid for calibration. An effective model has been developed first and experimentally elucidated to calibrate the static sensitivity in liquid. The proposed model eliminates inconvenience of static sensitivity calibration in liquid with possible contamination sources.

The static sensitivity based on force ...


Surface Morphology Of Platelet Adhesion Influenced By Activators, Inhibitors And Shear Stress, Melanie Groan Watson Oct 2010

Surface Morphology Of Platelet Adhesion Influenced By Activators, Inhibitors And Shear Stress, Melanie Groan Watson

Doctoral Dissertations

Platelet activation involves multiple events, one of which is the generation and release of nitric oxide (NO), a platelet aggregation inhibitor. Platelets simultaneously send and receive various agents that promote a positive and negative feedback control system during hemostasis. Although the purpose of platelet-derived NO is not fully understood, NO is known to inhibit platelet recruitment. NO's relatively large diffusion coefficient allows it to diffuse more rapidly than platelet agonists. It may thus be able to inhibit recruitment of platelets near the periphery of a growing thrombus before agonists have substantially accumulated in those regions.

Results from two studies ...


Halloysite Clay Nanotubes For Controlled Delivery Of Chemically Active Agents, Elshard Abdullayev Oct 2010

Halloysite Clay Nanotubes For Controlled Delivery Of Chemically Active Agents, Elshard Abdullayev

Doctoral Dissertations

In this work we explored the capabilities of halloysite nanotubes as capsules for encapsulation and controlled delivery of the chemically and biologically active substances. Halloysite is a two-layered aluminosilicate which has a predominantly hollow tubular structure in the submicron range and is chemically similar to kaolinite [1, 2].

In the first section of this work, we analyzed the structure of the halloysite nanotubes as well as its capability to encapsulate and deliver biologically and chemically active agents, similarities and differences between release characteristics of different agents and how these differences relate with their chemical structure. Models were used to describe ...


An Improved Layer-By-Layer Self-Assembly Technique To Generate Biointerfaces For Platelet Adhesion Studies: Dynamic Lbl, Juan Manuel Lopez Oct 2010

An Improved Layer-By-Layer Self-Assembly Technique To Generate Biointerfaces For Platelet Adhesion Studies: Dynamic Lbl, Juan Manuel Lopez

Doctoral Dissertations

Layer-by-layer self-assembly (LbL) is a technique that generates engineered nano-scale films, coatings, and particles. These nanoscale films have recently been used in multiple biomedical applications. Concurrently, microfabrication methods and advances in microfluidics are being developed and combined to create "Lab-on-a-Chip" technologies. The potential to perform complex biological assays in vitro as a first-line screening technique before moving on to animal models has made the concept of lab on a chip a valuable research tool.

Prior studies in the Biofluids Laboratory at Louisiana Tech have used layer-by-layer and in vitro biological assays to study thrombogenesis in a controlled, repeatable, engineered environment ...


Atom Scale Characterization Of The Near Apex Region Of An Atomic Force Microscope Tip, Christopher J. Tourek, Sriram Sundararajan Oct 2010

Atom Scale Characterization Of The Near Apex Region Of An Atomic Force Microscope Tip, Christopher J. Tourek, Sriram Sundararajan

Mechanical Engineering Publications

Three-dimensional atom probe tomography (APT) is successfully used to analyze the near-apex regions of an atomic force microscope (AFM) tip. Atom scale material structure and chemistry from APT analysis for standard silicon AFM tips and silicon AFM tips coated with a thin film of Cu is presented. Comparison of the thin film data with that observed using transmission electron microscopy indicates that APT can be reliably used to investigate the material structure and chemistry of the apex of an AFM tip at near atomic scales.


Intracellular Localisation, Geno- And Cytotoxic Response Of Poly N-Isopropylacrylamide (Pnipam) Nanoparticles To Human Keratinocyte (Hacat) And Colon Cells (Sw 480), Pratap Naha, Kunal Bhattacharya, Tiziana Tenuta, Kenneth Dawson, Iseult Lynch, Amaya Gracia, Fiona Lyng, Hugh Byrne Oct 2010

Intracellular Localisation, Geno- And Cytotoxic Response Of Poly N-Isopropylacrylamide (Pnipam) Nanoparticles To Human Keratinocyte (Hacat) And Colon Cells (Sw 480), Pratap Naha, Kunal Bhattacharya, Tiziana Tenuta, Kenneth Dawson, Iseult Lynch, Amaya Gracia, Fiona Lyng, Hugh Byrne

Articles

PNIPAM nanoparticles, with and without a covalentlylinked fluorescent label, were prepared by a free radical polymerisation technique. The cyto and genotoxicity of PNIPAM nanoparticles were analysed in two representative mammalian cell lines, SW480, a colon, and HaCaT, a dermal cell line. Physical characterisation in terms of particle size and zeta potential of the PNIPAM nanoparticles was carried out both in aqueous solution and in the appropriate cell culture media. Uptake and colocalisation of fluorescently labelled PNIPAM nanoparticles was monitored in both cell lines using confocal laser scanning microscopy. Genotoxicity analysis using the Comet assay was performed in both cell lines ...


Ultra-Thin-Film Aln Contour-Mode Resonators For Sensing Applications, Matteo Rinaldi, Chiara Zuniga, Gianluca Piazza Sep 2010

Ultra-Thin-Film Aln Contour-Mode Resonators For Sensing Applications, Matteo Rinaldi, Chiara Zuniga, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of ultra-thin-film (250 nm) aluminum nitride (AlN) microelectromechanical system (MEMS) contour mode resonators (CMRs) suitable for the fabrication of ultra-sensitive gravimetric sensors. The device thickness was opportunely scaled in order to increase the mass sensitivity, while keeping a constant frequency of operation. In this first demonstration the resonance frequency of the device was set to 178 MHz and a mass sensitivity as high as 38.96 KHz⋅μm2/fg was attained. This device demonstrates the unique capability of the CMR-S technology to decouple resonance frequency from mass ...


Ultra-Thin Super High Frequency Two-Port Aln Contour-Mode Resonators And Filters, Matteo Rinaldi, Chiara Zuniga, Chnegjie Zuo, Gianluca Piazza Sep 2010

Ultra-Thin Super High Frequency Two-Port Aln Contour-Mode Resonators And Filters, Matteo Rinaldi, Chiara Zuniga, Chnegjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the demonstration of a new class of ultra-thin (250 nm thick) super high frequency (SHF) AlN piezoelectric two-port resonators and filters. A thickness field excitation scheme was employed to excite a higher order contour extensional mode of vibration in an AlN nano plate (250 nm thick) above 3 GHz and synthesize a 1.96 GHz narrow-bandwidth channel-select filter. The devices of this work are able to operate over a frequency range from 1.9 to 3.5 GHz and are employed to synthesize the highest frequency MEMS filter based on electrically self-coupled AlN contour-mode resonators. Very ...


Uncertainty Quantification Study For A Comprehensive Electrostatic Mems Switch Model, Michael G. Snow, Anil K. Bajaj Sep 2010

Uncertainty Quantification Study For A Comprehensive Electrostatic Mems Switch Model, Michael G. Snow, Anil K. Bajaj

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

This work presents an uncertainty analysis of a comprehensive model for an electrostatic MEMS switch. The goal is to elucidate the effects of parameter variations on certain performance characteristics. A sufficiently detailed model of an electrostatically actuated beam is developed. This model accounts for various physical effects, including the electrostatic fringing field, finite length of electrodes, squeeze film damping, and contact between the beam and the dielectric layer. The performance characteristics of immediate interest are the static and dynamic pull-in voltages for switch. Using Latin Hypercube and other sampling methods, the model is evaluated to find these performances characteristics when ...


Coherent Electron Transport By Adiabatic Passage In An Imperfect Donor Chain, Rajib Rahman, Richard P. Muller, James E. Levy, Malcolm S. Carroll, Gerhard Klimeck, Andrew D. Greentree, Lloyd C. L. Hollenberg Sep 2010

Coherent Electron Transport By Adiabatic Passage In An Imperfect Donor Chain, Rajib Rahman, Richard P. Muller, James E. Levy, Malcolm S. Carroll, Gerhard Klimeck, Andrew D. Greentree, Lloyd C. L. Hollenberg

Birck and NCN Publications

Coherent Tunneling Adiabatic Passage (CTAP) has been proposed as a long-range physical qubit transport mechanism in solid-state quantum computing architectures. Although the mechanism can be implemented in either a chain of quantum dots or donors, a 1D chain of donors in Si is of particular interest due to the natural confining potential of donors that can in principle help reduce the gate densities in solid-state quantum computing architectures. Using detailed atomistic modeling, we investigate CTAP in a more realistic triple donor system in the presence of inevitable fabrication imperfections. In particular, we investigate how an adiabatic pathway for CTAP is ...


Providing A Theoretical Basis For Nanotoxicity Risk Analysis Departing From Traditional Physiologically-Based Pharmacokinetic (Pbpk) Modeling, Dirk P. Yamamoto Sep 2010

Providing A Theoretical Basis For Nanotoxicity Risk Analysis Departing From Traditional Physiologically-Based Pharmacokinetic (Pbpk) Modeling, Dirk P. Yamamoto

Theses and Dissertations

The same novel properties of engineered nanoparticles that make them attractive may also present unique exposure risks. But, the traditional physiologically-based pharmacokinetic (PBPK) modeling assumption of instantaneous equilibration likely does not apply to nanoparticles. This simulation-based research begins with development of a model that includes diffusion, active transport, and carrier mediated transport. An eigenvalue analysis methodology was developed to examine model behavior to focus future research. Simulations using the physicochemical properties of size, shape, surface coating, and surface charge were performed and an equation was determined which estimates area under the curve for arterial blood concentration, which is a surrogate ...


Negative Dielectrophoretic Capture Of Bacterial Spores In Food Matrices, Mehti Koklu, Seungkyung Park, Suresh D. Pillai, Ali Beskok Sep 2010

Negative Dielectrophoretic Capture Of Bacterial Spores In Food Matrices, Mehti Koklu, Seungkyung Park, Suresh D. Pillai, Ali Beskok

Mechanical & Aerospace Engineering Faculty Publications

A microfluidic device with planar square electrodes is developed for capturing particles from high conductivity media using negative dielectrophoresis (n-DEP). Specifically, Bacillus subtilis and Clostridium sporogenes spores, and polystyrene particles are tested in NaCl solution (0.05 and 0.225 S/m), apple juice (0.225 S/m), and milk (0.525 S/m). Depending on the conductivity of the medium, the Joule heating produces electrothermal flow (ETF), which continuously circulates and transports the particles to the DEP capture sites. Combination of the ETF and n-DEP results in different particle capture efficiencies as a function of the conductivity. Utilizing 20 ...


Münch, Morphology, Microfluidics – Our Structural Problem With The Phloem [Review Article], Michael Knoblauch, Winfried S. Peters Aug 2010

Münch, Morphology, Microfluidics – Our Structural Problem With The Phloem [Review Article], Michael Knoblauch, Winfried S. Peters

Winfried S. Peters

The sieve tubes of the phloem are enigmatic structures. Their role as channels for the distribution of assimilates was established in the 19th century, but their sensitivity to disturbations has hampered the elucidation of their transport mechanisms and its regulation ever since. Ernst Münch's classical monograph of 1930 is generally regarded as the first coherent theory of phloem transport, but the ‘Münchian’ pressure flow mechanism had been discussed already before the turn of the century. Münch's impact rather rested on his simple physical models of the phloem that visualized pressure flow in an intuitive way, and we argue ...