3,496 research outputs found
Expanding Carceral Frontiers: The 100-Mile Border Zone and Constituting Latinx Political Subjectivity
The thesis has two interrelated concerns. The first explores the emergence of the 100-mile border zone in order to study how the U.S. has expanded its borders inward and redefined notions of national security and carcerality. The second will define the 100-mile border as a carceral frontier that has emerged from previous years of racial security operations such as âOperation Wetbackâ in 1953. Moreover, I will demonstrate how the 100-mile border zone, a carceral frontier, blends the logic of security and the carceral in order to create a space of total state control. This inward turn of the 100-mile border zone and the security and carcerality of this space reveals much about the constitution of the sovereign stateâs right to define and secure its borders within the nation, the rights of the state over that of the citizen, a citizen\u27s right to free movement and due process, and the racial dynamics of security actions. To explore this contradictory logic of security, I conduct an analysis of security language on border and immigration âoperationsâ that constituted the emergence of the 100-mile border zone since 1953. Through this analysis, I will argue that the 100-mile border zone, as a carceral frontier, is a new theoretical development in Critical Carceral Studies. In this way, this thesis will engage in Securitization Studies, Border Theory, and Carceral theories. This type of analysis will reveal that the 100-mile border zone, and the making of this carceral frontier, is inextricably bound to the rights and status of Latinx
Electron Power-Law Spectra in Solar and Space Plasmas
Particles are accelerated to very high, non-thermal energies in solar and
space plasma environments. While energy spectra of accelerated electrons often
exhibit a power law, it remains unclear how electrons are accelerated to high
energies and what processes determine the power-law index . Here, we
review previous observations of the power-law index in a variety of
different plasma environments with a particular focus on sub-relativistic
electrons. It appears that in regions more closely related to magnetic
reconnection (such as the `above-the-looptop' solar hard X-ray source and the
plasma sheet in Earth's magnetotail), the spectra are typically soft ( 4). This is in contrast to the typically hard spectra ( 4) that are observed in coincidence with shocks. The difference
implies that shocks are more efficient in producing a larger non-thermal
fraction of electron energies when compared to magnetic reconnection. A caveat
is that during active times in Earth's magnetotail, values seem
spatially uniform in the plasma sheet, while power-law distributions still
exist even in quiet times. The role of magnetotail reconnection in the electron
power-law formation could therefore be confounded with these background
conditions. Because different regions have been studied with different
instrumentations and methodologies, we point out a need for more systematic and
coordinated studies of power-law distributions for a better understanding of
possible scaling laws in particle acceleration as well as their universality.Comment: 67 pages, 15 figures; submitted to Space Science Reviews; comments
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Branding the nation: Towards a better understanding
This paper aims to clarify some misunderstanding about nation branding. It examines the origins and interpretations of the concept, and draws a comparison between nation branding and commercial branding. A new definition is offered that emphasises the need to shift from âbrandingâ the nation to nation image management
Energy Level Statistics of the U(5) and O(6) Symmetries in the Interacting Boson Model
We study the energy level statistics of the states in U(5) and O(6) dynamical
symmetries of the interacting boson model and the high spin states with
backbending in U(5) symmetry. In the calculations, the degeneracy resulting
from the additional quantum number is eliminated manually. The calculated
results indicate that the finite boson number effect is prominent. When
has a value close to a realistic one, increasing the interaction strength of
subgroup O(5) makes the statistics vary from Poisson-type to GOE-type and
further recover to Poisson-type. However, in the case of , they
all tend to be Poisson-type. The fluctuation property of the energy levels with
backbending in high spin states in U(5) symmetry involves a signal of shape
phase transition between spherical vibration and axial rotation.Comment: 38 pages, 13 figure
Influence of Si doping on InAs/GaAs quantum dot solar cells with AlAs cap layers
A novel all-optical forward-viewing photoacoustic probe using a flexible coherent fibre-optic bundle and a Fabry- Perot (FP) ultrasound sensor has been developed. The fibre bundle, along with the FP sensor at its distal end, synthesizes a high density 2D array of wideband ultrasound detectors. Photoacoustic waves arriving at the sensor are spatially mapped by optically scanning the proximal end face of the bundle in 2D with a CW wavelength-tunable interrogation laser. 3D images are formed from the detected signals using a time-reversal image reconstruction algorithm. The system has been characterized in terms of its PSF, noise-equivalent pressure and field of view. Finally, the high resolution 3D imaging capability has been demonstrated using arbitrary shaped phantoms and duck embryo
Si-Doped InAs/GaAs Quantum-Dot Solar Cell With AlAs Cap Layers
One of the requirements for strong subbandgap photon absorption in the quantum-dot intermediate-band solar cell (QD-IBSC) is the partial filling of the intermediate band. Studies have shown that the partial filling of the intermediate band can be achieved by introducing Si doping to the QDs. However, the existence of too many Si dopants leads to the formation of point defects and, hence, a reduction of photocurrent. In this study, the effect of Si doping on InAs/GaAs QD solar cells with AlAs cap layers is studied. The AlAs cap layers prevent the formation of the wetting layer during QD growth and reduce the Si doping density needed to achieve QD state filling. Furthermore, the passivation of defect states in the QD with moderate Si doping is demonstrated, which leads to an enhancement of the carrier lifetime in the QDs and, hence, the open-circuit voltage
An Investigation of the Role of Radiative and Nonradiative Recombination Processes in InAs/GaAs 1âx Sb x Quantum Dot Solar Cells
An InAs/GaAs0.86 Sb 0.14 quantum dot solar cell and a GaAsSb control cell were investigated using temperature-dependent current densityâvoltage (JâV), external quantum efficiency, photoluminescence (PL), and electroluminescence (EL) measurements. Thermally activated defect states associated with the GaAsSb matrix material are found to account for the reduction of the performance of the solar cell. The rapid quenching of the PL and EL intensity, along with the shift (above 150 K) of the dominant recombination process during spontaneous emission (EL), further indicates the prevalence of nonradiative processes at elevated temperatures in these systems. These findings are also supported by a reduction in the open-circuit voltage at elevated temperatures in these devices
Low temperature superlattice in monoclinic PZT
TEM has shown that the strongly piezoelectric material Pb(Zr0.52Ti0.48)O3
separates into two phases at low temperatures. The majority phase is the
monoclinic phase previously found by x-ray diffraction. The minority phase,
with a nanoscale coherence length, is a slightly distorted variant of the first
resulting from the anti-phase rotation of the oxygen octahedra about [111].
This work clears up a recent controversy about the origin of superlattice peaks
in these materials, and supports recent theoretical results predicting the
coexistence of ferroelectric and rotational instabilities.Comment: REVTeX4, 4 eps figures embedded. JPG version of figs. 2&4 is also
include
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