+publisher:"Brown University" +contributor:("Ling, Xinsheng")

1. Miao, Wang. Nonlinear Transport in Solid-State Nanopores.

Degree: PhD, Physics, 2015, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:419425/

► Research on DNA translocation through nanopore has drawn much attention because of its potential in DNA sequencing and biosensing. A lot of issues about translocation… (more)

▼ Research on DNA translocation through nanopore has drawn much attention because of its potential in DNA sequencing and biosensing. A lot of issues about translocation process have been found in recent years, such as capture kinetics, thermal fluctuations, electro-osmotic flow, etc. Due to the flexibility of DNA molecules, there are many complicated folded translocation events, which make the task of data analysis difficult. Here we use semi-flexible fd virus as a model system for studying translocation dynamics. The fd virus has persistent length around several micrometers, larger than the diameter of a nanopore, making folded translocation unlikely. In our study, distinct types of translocation events have been observed and a scheme of classification is developed. We also observe the subtle difference in their translocation dynamics of wild and mutant types of fd viruses due to different degrees of flexibility measured by their persistent length. A systematic method of measuring the current drops and time intervals for the fd translocations is developed and is used to construct a scatter plot, the latter led to the discovery of the Stotz-Wien effect in nanopore, nonlinear electrophoresis in strong electric field. The Stotz-Wien effect is studied with different types of virus and under different measuring salt concentrations. From comparison between experimental results and theoretic prediction, we found that electro-osmotic flow (EOF) is very crucial to the translocation process. We studied the EOF around different shaped particles and as well as within nanopores through numerical approach by using Poisson-Nernst-Planck (PNP) model. From our calculation, we confirm that Stotz-Wien effect is a consequence of polarized Debye cloud caused by the strong electric field. Finally, we show that the non-uniform distributed EOF within nanopore plays a very important role in translocation process, which should be considered when designing sequence method. Advisors/Committee Members: Ling, Xinsheng (Director), Tang, Jay (Reader), Feldman, Dmitri (Reader).

Subjects/Keywords: solid-state nanopore

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Miao, W. (2015). Nonlinear Transport in Solid-State Nanopores. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:419425/

Chicago Manual of Style (16^th Edition):

Miao, Wang. “Nonlinear Transport in Solid-State Nanopores.” 2015. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:419425/.

MLA Handbook (7^th Edition):

Miao, Wang. “Nonlinear Transport in Solid-State Nanopores.” 2015. Web. 26 Jan 2021.

Vancouver:

Miao W. Nonlinear Transport in Solid-State Nanopores. [Internet] [Doctoral dissertation]. Brown University; 2015. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:419425/.

Council of Science Editors:

Miao W. Nonlinear Transport in Solid-State Nanopores. [Doctoral Dissertation]. Brown University; 2015. Available from: https://repository.library.brown.edu/studio/item/bdr:419425/

2. YU, LICHAO. Defects in Two Dimensional Colloidal Crystals.

Degree: PhD, Physics, 2015, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:419422/

► We use digital video microscopy to study the defects in two-dimensional colloidal crystals (2DCC). A crystalline solid, different from its liquid state, preserves long-wavelength shear… (more)

Subjects/Keywords: Defects

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

YU, L. (2015). Defects in Two Dimensional Colloidal Crystals. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:419422/

Chicago Manual of Style (16^th Edition):

YU, LICHAO. “Defects in Two Dimensional Colloidal Crystals.” 2015. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:419422/.

MLA Handbook (7^th Edition):

YU, LICHAO. “Defects in Two Dimensional Colloidal Crystals.” 2015. Web. 26 Jan 2021.

Vancouver:

YU L. Defects in Two Dimensional Colloidal Crystals. [Internet] [Doctoral dissertation]. Brown University; 2015. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:419422/.

Council of Science Editors:

YU L. Defects in Two Dimensional Colloidal Crystals. [Doctoral Dissertation]. Brown University; 2015. Available from: https://repository.library.brown.edu/studio/item/bdr:419422/

3. Hanson, Helen A. The Crystallography of Vortex Matter in a Niobium Crystal.

Degree: PhD, Physics, 2012, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:297704/

► The vortex matter in type-II superconductors continues to be a subject of great fascination in condensed matter physics. A longstanding theoretical and experimental problem is… (more)

▼ The vortex matter in type-II superconductors continues to be a subject of great fascination in condensed matter physics. A longstanding theoretical and experimental problem is the identification of the ground state of the vortex lines in the presence of quenched atomic disorder which acts as random pinning centers. A possible edge contamination model has been proposed as a mechanism behind the seemingly contradictory experimental results for the ordered state of matter. This model could also explain the lack of universality for the peak effect behavior exhibited in samples with otherwise similar phase diagrams. Using a novel neutron diffraction technique, we report structural evidence for this edge contamination mechanism. This high-resolution method is used to study the fine structure of the vortex matter in a niobium crystal with a weak peak effect and a disordered zero-field-cooled vortex matter. We find this disordered state is metastable and that it can be restructured through a thermal cycling procedure. The results are explained in a strained lattice framework. We then perform Reverse Monte Carlo Refinements on our neutron scattering data and the possible vortex structures for our crystal agree with experimental results from an approach that combines spatial information with reciprocal space scattering. Having confirmed the existence of an edge contamination mechanism in this sample, we oxidize the surface in order to reduce the impact of the inhomogeneous surface barrier. By repeating our neutron diffraction measurements, we find that oxidation process has smoothed the magnetic field profile through the sample and improves the overall structural order of the zero-field-cooled vortex matter. On the other hand, the field-cooled vortex matter structure should be independent of any edge contamination effect but surprisingly, this scattering intensity in fact doubles after surface oxidation. This result suggests that there is another source of disorder in the niobium crystal that has been affected. We discuss our results in the context of the peak effect and Bragg glass models. Advisors/Committee Members: Ling, Xinsheng (Director), Kosterlitz, James (Reader), Mitrovic, Vesna (Reader).

Subjects/Keywords: vortex phyiscs

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hanson, H. A. (2012). The Crystallography of Vortex Matter in a Niobium Crystal. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:297704/

Chicago Manual of Style (16^th Edition):

Hanson, Helen A. “The Crystallography of Vortex Matter in a Niobium Crystal.” 2012. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:297704/.

MLA Handbook (7^th Edition):

Hanson, Helen A. “The Crystallography of Vortex Matter in a Niobium Crystal.” 2012. Web. 26 Jan 2021.

Vancouver:

Hanson HA. The Crystallography of Vortex Matter in a Niobium Crystal. [Internet] [Doctoral dissertation]. Brown University; 2012. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:297704/.

Council of Science Editors:

Hanson HA. The Crystallography of Vortex Matter in a Niobium Crystal. [Doctoral Dissertation]. Brown University; 2012. Available from: https://repository.library.brown.edu/studio/item/bdr:297704/

4. Wang, Xi. 3D Neutron Diffraction Studies on the Vortex Lattice.

Degree: PhD, Physics, 2012, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:297705/

► In condensed matter physics the vortex lattice of type-II superconductors provides a prototype for studying the effect of random pinning on elastic systems. One important… (more)

▼ In condensed matter physics the vortex lattice of type-II superconductors provides a prototype for studying the effect of random pinning on elastic systems. One important problem is to understand the structural transition from a theoretically predicted ordered Bragg glass phase to a disordered vortex liquid phase. Defects, such as screw dislocations, should play an important role in mediating this order-disorder transition. It is important to confirm the existence of these defect structures in the vortex lattice. Experimentally it is difficult to probe the detailed defect structures inside the vortex lattice. Traditional methods can only provide information on the surface configuration or an averaged picture of the bulk behavior of the vortex lattice. Here we use a novel high-resolution neutron diffraction technique to probe the angular orientation of the lattice planes as the flux lines traverse the atomic crystal. Our results provide structural evidence for screw dislocations inside the vortex lattice. The anisotropic defect structure in the underlying atomic lattice serves as a symmetry breaking field for the vortex lattice. The strong dependence of the vortex lattice structure on the growth procedure reveals that the system is metastable and can be perturbed through thermal cycling to a possible ground state. We measure the structure of the vortex lattice under different applied magnetic fields and temperatures to study the interplay between vortex-vortex interaction, vortex-atomic lattice interaction, and thermal fluctuations. This high-resolution neutron diffraction technique opens up a new way in studying the detailed structure of the vortex lattice. Our results suggest that the vortex lattice in low temperature superconductors with anisotropic defects in the atomic lattice could be an excellent candidate for exploring the entangled flux liquid phase. Advisors/Committee Members: Ling, Xinsheng (Director), Kosterlitz, J. (Reader), Mitrovic, Vesna (Reader).

Subjects/Keywords: neutron diffraction

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, X. (2012). 3D Neutron Diffraction Studies on the Vortex Lattice. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:297705/

Chicago Manual of Style (16^th Edition):

Wang, Xi. “3D Neutron Diffraction Studies on the Vortex Lattice.” 2012. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:297705/.

MLA Handbook (7^th Edition):

Wang, Xi. “3D Neutron Diffraction Studies on the Vortex Lattice.” 2012. Web. 26 Jan 2021.

Vancouver:

Wang X. 3D Neutron Diffraction Studies on the Vortex Lattice. [Internet] [Doctoral dissertation]. Brown University; 2012. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:297705/.

Council of Science Editors:

Wang X. 3D Neutron Diffraction Studies on the Vortex Lattice. [Doctoral Dissertation]. Brown University; 2012. Available from: https://repository.library.brown.edu/studio/item/bdr:297705/

5. Jung, Hyeyun. Thermal Diffusion Shock Waves in a Linear Temperature Field and Comparison of Ultrasonic Distillation to Sparging of Liquid Mixtures.

Degree: PhD, Physics, 2012, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:297708/

► The Ludwig-Soret effect, also known as thermal diffusion, refers to the separation of mixtures in a temperature gradient. Thermal diffusion is governed by a pair… (more)

▼ The Ludwig-Soret effect, also known as thermal diffusion, refers to the separation of mixtures in a temperature gradient. Thermal diffusion is governed by a pair of coupled differential equations which reduce to a nonlinear partial differential equation when the temperature profile is specified. Here two solutions are given to the partial differential equation describing thermal diffusion in a linear temperature field where the components are constrained in space. The first solution considers thermal diffusion without the effects of mass diffusion and shows the underlying motion of the components of the mixture to be that of shock waves. The second solution is an exact solution of the Ludwig-Soret equation that includes both the effect of the thermal gradient and mass diffusion. An additional solution is found for the problem of thermal diffusion in unbounded space. A new experimental method was developed to monitor distributions of components of the mixture in a linear temperature field based on probing a cell containing fluorescent nanoparticles with a confocal microscope. The nanoparticles were chemically synthesized and labeled with a fluorophore that absorbed 488 nm radiation and fluoresced at a 520 nm peak. The temperature gradient in the cell was generated by cooling one surface of the cell, a sapphire plate, with flowing water and electrically heating the other surface, which was an indium tin oxide coated glass plate. The dynamics of the separation of the mixture was recorded by monitoring fluorescence from the particles with the scanning confocal microscope. Data were fitted to a new numerical solution to the full partial differential equation for thermal diffusion with mass diffusion included. The method developed here is shown to provide Soret parameters, including the thermal diffusion factor and the Soret coefficient, based on either a single recording of the terminal density fraction profile, or by fitting the density profile at several times with the results of numerical integration. Ultrasonic distillation was investigated. Experiments were carried out to verify the recently reported, perfect separation of ethanol from water by ultrasonic distillation. Ultrasonic distillation refers to the application of intense ultrasound to a liquid resulting in the formation of an ultrasonic fountain that generates both mist and vapor. Here, the composition of the vapor and aerosol above an ultrasonic fountain was determined as a function of irradiation time and compared with the results of sparging for five different solutions. The experimental apparatus for determining the efficiency of separation consists of a glass vessel containing a piezoelectric transducer driven at either 1.65 or 2.40 MHz. Dry nitrogen was passed over the ultrasonic fountain to remove the vapor and aerosol. The composition of the liquid solutions remaining in the apparatus were recorded following irradiation using gas chromatography, refractive index measurement, nuclear magnetic resonance, or spectrophotometry as diagnostics for the… Advisors/Committee Members: Diebold, Gerald (Director), Ling, Xinsheng (Reader), Valles, James (Reader).

Subjects/Keywords: Thermal Diffusion

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Jung, H. (2012). Thermal Diffusion Shock Waves in a Linear Temperature Field and Comparison of Ultrasonic Distillation to Sparging of Liquid Mixtures. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:297708/

Chicago Manual of Style (16^th Edition):

Jung, Hyeyun. “Thermal Diffusion Shock Waves in a Linear Temperature Field and Comparison of Ultrasonic Distillation to Sparging of Liquid Mixtures.” 2012. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:297708/.

MLA Handbook (7^th Edition):

Jung, Hyeyun. “Thermal Diffusion Shock Waves in a Linear Temperature Field and Comparison of Ultrasonic Distillation to Sparging of Liquid Mixtures.” 2012. Web. 26 Jan 2021.

Vancouver:

Jung H. Thermal Diffusion Shock Waves in a Linear Temperature Field and Comparison of Ultrasonic Distillation to Sparging of Liquid Mixtures. [Internet] [Doctoral dissertation]. Brown University; 2012. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:297708/.

Council of Science Editors:

Jung H. Thermal Diffusion Shock Waves in a Linear Temperature Field and Comparison of Ultrasonic Distillation to Sparging of Liquid Mixtures. [Doctoral Dissertation]. Brown University; 2012. Available from: https://repository.library.brown.edu/studio/item/bdr:297708/

6. Obeid, Dina N. Noisy Stabilized Kuramoto-Sivashinsky: A modelfor studying state selection in far fromequilibrium systems.

Degree: PhD, Physics, 2011, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:11168/

► In this thesis we address the question of pattern selection in spatially extendedsystems in the presence of stochastic noise. As a model equation, we study… (more)

Subjects/Keywords: Nonequilibrium

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Obeid, D. N. (2011). Noisy Stabilized Kuramoto-Sivashinsky: A modelfor studying state selection in far fromequilibrium systems. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:11168/

Chicago Manual of Style (16^th Edition):

Obeid, Dina N. “Noisy Stabilized Kuramoto-Sivashinsky: A modelfor studying state selection in far fromequilibrium systems.” 2011. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:11168/.

MLA Handbook (7^th Edition):

Obeid, Dina N. “Noisy Stabilized Kuramoto-Sivashinsky: A modelfor studying state selection in far fromequilibrium systems.” 2011. Web. 26 Jan 2021.

Vancouver:

Obeid DN. Noisy Stabilized Kuramoto-Sivashinsky: A modelfor studying state selection in far fromequilibrium systems. [Internet] [Doctoral dissertation]. Brown University; 2011. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:11168/.

Council of Science Editors:

Obeid DN. Noisy Stabilized Kuramoto-Sivashinsky: A modelfor studying state selection in far fromequilibrium systems. [Doctoral Dissertation]. Brown University; 2011. Available from: https://repository.library.brown.edu/studio/item/bdr:11168/

7. Dong, Ankun. Single-molecule Nanoscopy of RNA Polymerase II Transcription at a Single Gene in Live Cells.

Degree: Department of Physics, 2017, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:733314/

► Single-molecule approaches enable us to follow the movement, interactions and conformational dynamics of individual molecules in real-time, thus providing novel insights in complex biochemical systems… (more)

▼ Single-molecule approaches enable us to follow the movement, interactions and conformational dynamics of individual molecules in real-time, thus providing novel insights in complex biochemical systems that have remained masked in the ensemble averaging of traditional bulk biochemical approaches. Recent advances in single-molecule tracking, fluorescence spectroscopy and subdiffraction optical microscopy have unveiled unprecedented views of molecular processes in live cells. To extract quantitative information from individual molecules in the high background noise, these techniques are often based on in vitro reconstituted systems with either surface-immobilized or freely-diffusing biomolecules in dilute conditions. Live cell, real-time imaging, tracking and counting biomolecules in their native, crowded intracellular environment currently remain an extremely challenging task. Based on the numerical simulation, I built the real time tracking 3D STED nanoscopy enabling single molecule detection. With the new technique, I perform oligo-nucleotide hybridization detection experiment in vitro as well as study the mechanism of RNA Polymerase II transcription in living cells at single molecule level. Basically, I reveal the accumulation of Pol II molecules and quantified nearly 10 Pol II molecules in the cluster during active transcription at a tagged mini-gene in the native environment. In addition, mini-gene transcription does not involve transient Pol II clustering at pre-initiation by kinetic analysis enabled by target-locking overVII multiple transcription rounds, arguing against the persistence of accumulated Pol IIs in the absence of transcription or extensive Pol II recycling-related spatial compartmentalization. What’s more, I find that single Pol II molecules are stochastically recruited from the nucleoplasm, enter into productive elongation and are predominantly released instead of recycled upon termination. The results set up a quantitative framework for investigating Pol II dynamics at single genes at single molecule level, and also demonstrate that the potential and powerful use of real time tracking 3D STED nanoscopy in elucidating the complex biological mechanisms in vivo. Advisors/Committee Members: Ling, Xinsheng Sean (Advisor), Kosterlitz, J. Michael (Reader), Diebold, Gerald J. (Reader).

Subjects/Keywords: Molecular biology

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dong, A. (2017). Single-molecule Nanoscopy of RNA Polymerase II Transcription at a Single Gene in Live Cells. (Thesis). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:733314/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Dong, Ankun. “Single-molecule Nanoscopy of RNA Polymerase II Transcription at a Single Gene in Live Cells.” 2017. Thesis, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:733314/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Dong, Ankun. “Single-molecule Nanoscopy of RNA Polymerase II Transcription at a Single Gene in Live Cells.” 2017. Web. 26 Jan 2021.

Vancouver:

Dong A. Single-molecule Nanoscopy of RNA Polymerase II Transcription at a Single Gene in Live Cells. [Internet] [Thesis]. Brown University; 2017. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:733314/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Dong A. Single-molecule Nanoscopy of RNA Polymerase II Transcription at a Single Gene in Live Cells. [Thesis]. Brown University; 2017. Available from: https://repository.library.brown.edu/studio/item/bdr:733314/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

8. Luo, Xu. Thermodynamic Studies of Phase Transitions and Emerging Orders in Unconventional Superconductors.

Degree: PhD, Physics, 2015, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:419516/

► The nematic phase transition in Fe-based superconductors (FeSCs) has been a topic under intensive investigation. So far it is commonly accepted that the structural transition… (more)

▼ The nematic phase transition in Fe-based superconductors (FeSCs) has been a topic under intensive investigation. So far it is commonly accepted that the structural transition from tetragonal (C4) to orthorhombic (C2) symmetry in FeSCs has an electronic nematic origin due to the unusual anisotropy in resistivity, optical conductivity and orbital occupancy observed above the structural transition. However, recent studies of (Ba, Eu)Fe2(As1-xPx)2 by magnetic torque measurements show the existence of a “true” nematic transition well above the commonly accepted structural/nematic transition .Controversies about this “true” nematic phase transition arise as residue strains or external applied fields are known to break C4 symmetry and render the structural transition merely a crossover. We performed high resolution AC micro-calorimetry and SQUID magnetometry measurements of BaFe2(As1-xPx)2 (x=0, 0.3) to investigate the various phase transitions and to explore the “true” nematic phase transition. The advantageous design of our membrane calorimeter allows us to perform high resolution studies of the thermodynamic phase transitions without any symmetry breaking fields. Our results suggest that there is not a second order “true” nematic phase transition in BaFe2(As1-xPx)2 even though the Ginzburg-Landau model used to fit the magnetic torque data indicates that the expected thermal anomaly should be within our experimental resolution. In addition to the above, we present specific heat and magnetization studies of Ba1-xNaxFe2As2 in search of the recent discovered emergent reentrant C2 to C4 symmetry SDW transition in this series of compound. Our results indeed locate a new phase transition in Ba0.74Na0.26Fe2As2 at 45K. However, the absence of the conventional SDW transition at around 80K in our data leaves doubt about the exact nature of this new phase transition. We also systematically studied the effects of heavy ion irradiation (HII) on the anisotropy of YBCO single crystals by angular rotation specific heat measurements. We found that the anisotropy of YBCO decreases by approximately a factor of two with an irradiation dose of 6T (matching field). The dependence of anisotropy on irradiation doses agrees well with the prediction from a simple phenomenological model that takes into account the anisotropic scattering caused by columnar defects created in HII. Advisors/Committee Members: Ling, Xinsheng (Director), Welp, Ulrich (Director), Marston, John (Reader), Mitrovic, Vesna (Reader).

Subjects/Keywords: Fe-based superconductor

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Luo, X. (2015). Thermodynamic Studies of Phase Transitions and Emerging Orders in Unconventional Superconductors. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:419516/

Chicago Manual of Style (16^th Edition):

Luo, Xu. “Thermodynamic Studies of Phase Transitions and Emerging Orders in Unconventional Superconductors.” 2015. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:419516/.

MLA Handbook (7^th Edition):

Luo, Xu. “Thermodynamic Studies of Phase Transitions and Emerging Orders in Unconventional Superconductors.” 2015. Web. 26 Jan 2021.

Vancouver:

Luo X. Thermodynamic Studies of Phase Transitions and Emerging Orders in Unconventional Superconductors. [Internet] [Doctoral dissertation]. Brown University; 2015. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:419516/.

Council of Science Editors:

Luo X. Thermodynamic Studies of Phase Transitions and Emerging Orders in Unconventional Superconductors. [Doctoral Dissertation]. Brown University; 2015. Available from: https://repository.library.brown.edu/studio/item/bdr:419516/

9. McFarland, James M. Single-Neuron and Network Dynamics in the Neocortical-Entorhinal-Hippocampal Circuit.

Degree: PhD, Physics, 2011, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:11242/

► The neocortical-entorhinal-hippocampal circuit has been shown to play an important role in memory formation and consolidation. Furthermore, the entorhinal cortex (EC) and the hippocampus are… (more)

▼ The neocortical-entorhinal-hippocampal circuit has been shown to play an important role in memory formation and consolidation. Furthermore, the entorhinal cortex (EC) and the hippocampus are thought to be key components of the brain�s spatial processing system. I examine both of these aspects using quantitative analysis of single-neuron and network activity. In part 1, I investigate the dynamics of the neocortical-entorhinal-hippocampal circuit in anesthetized mice where cortical neurons alternate between a depolarized and spiking �UP� state and a hyperpolarized and quiescent �DOWN� state. I first demonstrate an explicit-duration hidden Markov model algorithm for inferring UP-DOWN states (UDS) from both membrane potential and local field potential recordings. I then apply this method to study UDS in superficial neurons of the medial and lateral EC (MEC and LEC). MEC, but not LEC, neurons are shown to selectively decouple from the neocortical UDS and exhibit persistent UP states whose duration is quantized in units of neocortical UDS cycles. In contrast, LEC, but not MEC, neurons are found to display periods of pronounced 2-4Hz oscillations which are phase-locked to the ongoing UDS. In part 2, I examine the hippocampal �rate� and �temporal� codes for position in freely behaving mice. The spatial and temporal firing properties of hippocampal neurons in GluA1 knockout (KO) mice are found to be dramatically altered relative to wild-type mice, and the network theta and gamma oscillations are also markedly reduced in the KO animals. I then examine the precession of hippocampal neurons� spike phase relative to the theta rhythm, and demonstrate a novel dependence of the temporal code on behavior. These studies reveal important mechanisms by which the EC could shape neocortical-hippocampal interactions during sleep, and advance our understanding of how the hippocampal �rate� and �temporal� codes are generated and relate to behavior. Advisors/Committee Members: Mehta, Mayank (Director), Stein, Derek (Director), Stein, Derek (Reader), Ling, Xinsheng (Reader), Mehta, Mayank (Director), Stein, Derek (Director), Stein, Derek (Reader), Ling, Xinsheng (Reader).

Subjects/Keywords: UP-DOWN states

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

McFarland, J. M. (2011). Single-Neuron and Network Dynamics in the Neocortical-Entorhinal-Hippocampal Circuit. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:11242/

Chicago Manual of Style (16^th Edition):

McFarland, James M. “Single-Neuron and Network Dynamics in the Neocortical-Entorhinal-Hippocampal Circuit.” 2011. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:11242/.

MLA Handbook (7^th Edition):

McFarland, James M. “Single-Neuron and Network Dynamics in the Neocortical-Entorhinal-Hippocampal Circuit.” 2011. Web. 26 Jan 2021.

Vancouver:

McFarland JM. Single-Neuron and Network Dynamics in the Neocortical-Entorhinal-Hippocampal Circuit. [Internet] [Doctoral dissertation]. Brown University; 2011. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:11242/.

Council of Science Editors:

McFarland JM. Single-Neuron and Network Dynamics in the Neocortical-Entorhinal-Hippocampal Circuit. [Doctoral Dissertation]. Brown University; 2011. Available from: https://repository.library.brown.edu/studio/item/bdr:11242/

10. Stewart, Michael D. Superconductor to Insulator Transitions in Amorphous Nanohoneycomb Films.

Degree: PhD, Physics, 2008, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:48/

► Two dimensional electronic systems exhibit a wide variety of phenomena including the quantum Hall effect, weak and strong localization, and metal-insulator transitions, including the superconductor… (more)

▼ Two dimensional electronic systems exhibit a wide variety of phenomena including the quantum Hall effect, weak and strong localization, and metal-insulator transitions, including the superconductor to insulator transition (SIT). In each case the possibility of a universal explanation, independent of the microscopic details of the system, has tantalized researchers. In some cases, such as the temperature dependence of the conductance of metal films, or the spacing of resistance plateaus in the Hall effect, universal behavior is without doubt. Universal explanations of the amorphous film SIT revolve around the dirty Boson model, in which the sharp rise in the resistance of a film at low temperature is due to the localization of Cooper pairs. The existence of long-lived Cooper pairs in an electrically insulating system, the central assumption of the model, has remained in doubt because some measurements support the assertion and others refute it. This thesis addresses this experimental dissonance by investigating the SITs of amorphous Bismuth films perforated with a regular nanohoneycomb (NHC) array of holes. The nanoscale perforations allow a direct measurement of phase coherent Cooper pairs with an applied magnetic field. On the insulating side of the disorder driven SIT the resistance as a function of magnetic field oscillates with a period, h/2eS, where S is the area of a unit cell of holes. The 2e period betrays the presence of localized Cooper pairs in an electrically insulating state. The magnetoresistance of weak superconducting films reveals several SITs which qualitatively resemble the disorder driven SIT. The behavior of these transitions borrows heavily from both sides of a dichotomy exhibited by different materials through their field driven SITs. NHC films show activated resistances and a large peak in the magnetoresistance, analogous to the more spectacular behavior of some materials. However, they also show a weak, almost metallic, temperature dependence for a range of fields near the SIT, not unlike the metallic phase of unpatterned Bismuth and other materials. These results suggest that an underlying multiply connected geometry in ostensibly amorphous, unpatterned films may account for some of the range of material dependent behavior. Advisors/Committee Members: Valles, James (director), Feldman, Dima (reader), Ling, Xinsheng (reader).

Subjects/Keywords: superconductor insulator transition

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Stewart, M. D. (2008). Superconductor to Insulator Transitions in Amorphous Nanohoneycomb Films. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:48/

Chicago Manual of Style (16^th Edition):

Stewart, Michael D. “Superconductor to Insulator Transitions in Amorphous Nanohoneycomb Films.” 2008. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:48/.

MLA Handbook (7^th Edition):

Stewart, Michael D. “Superconductor to Insulator Transitions in Amorphous Nanohoneycomb Films.” 2008. Web. 26 Jan 2021.

Vancouver:

Stewart MD. Superconductor to Insulator Transitions in Amorphous Nanohoneycomb Films. [Internet] [Doctoral dissertation]. Brown University; 2008. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:48/.

Council of Science Editors:

Stewart MD. Superconductor to Insulator Transitions in Amorphous Nanohoneycomb Films. [Doctoral Dissertation]. Brown University; 2008. Available from: https://repository.library.brown.edu/studio/item/bdr:48/

11. Wu, Shanshan. Fabrication of nanopore systems and their application to DNA manipulation.

Degree: PhD, Physics, 2008, Brown University

URL: https://repository.library.brown.edu/studio/item/bdr:28/

► Nanopore system is important for its many promising applications in rapid DNA sequencing, large biological molecule detection, polynucleotide-enzyme interaction study and etc. Following the first… (more)

Subjects/Keywords: Nanopores

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wu, S. (2008). Fabrication of nanopore systems and their application to DNA manipulation. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:28/

Chicago Manual of Style (16^th Edition):

Wu, Shanshan. “Fabrication of nanopore systems and their application to DNA manipulation.” 2008. Doctoral Dissertation, Brown University. Accessed January 26, 2021. https://repository.library.brown.edu/studio/item/bdr:28/.

MLA Handbook (7^th Edition):

Wu, Shanshan. “Fabrication of nanopore systems and their application to DNA manipulation.” 2008. Web. 26 Jan 2021.

Vancouver:

Wu S. Fabrication of nanopore systems and their application to DNA manipulation. [Internet] [Doctoral dissertation]. Brown University; 2008. [cited 2021 Jan 26]. Available from: https://repository.library.brown.edu/studio/item/bdr:28/.

Council of Science Editors:

Wu S. Fabrication of nanopore systems and their application to DNA manipulation. [Doctoral Dissertation]. Brown University; 2008. Available from: https://repository.library.brown.edu/studio/item/bdr:28/

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations