1,359 research outputs found
Energy Dissipation and Regularity for a Coupled Navier-Stokes and Q-Tensor System
We study a complex non-newtonian fluid that models the flow of nematic liquid
crystals. The fluid is described by a system that couples a forced
Navier-Stokes system with a parabolic-type system. We prove the existence of
global weak solutions in dimensions two and three. We show the existence of a
Lyapunov functional for the smooth solutions of the coupled system and use the
cancellations that allow its existence to prove higher global regularity, in
dimension two. We also show the weak-strong uniqueness in dimension two
Well-posedness of the Ericksen-Leslie system
In this paper, we prove the local well-posedness of the Ericksen-Leslie
system, and the global well-posednss for small initial data under the physical
constrain condition on the Leslie coefficients, which ensures that the energy
of the system is dissipated. Instead of the Ginzburg-Landau approximation, we
construct an approximate system with the dissipated energy based on a new
formulation of the system.Comment: 16 page
Blow up criterion for compressible nematic liquid crystal flows in dimension three
In this paper, we consider the short time strong solution to a simplified
hydrodynamic flow modeling the compressible, nematic liquid crystal materials
in dimension three. We establish a criterion for possible breakdown of such
solutions at finite time in terms of the temporal integral of both the maximum
norm of the deformation tensor of velocity gradient and the square of maximum
norm of gradient of liquid crystal director field.Comment: 22 page
Design and fabrication of densely integrated silicon quantum dots using a VLSI compatible hydrogen silsesquioxane electron beam lithography process
Hydrogen silsesquioxane (HSQ) is a high resolution negative-tone electron beam resist allowing for direct transfer of nanostructures into silicon-on-insulator. Using this resist for electron beam lithography, we fabricate high density lithographically defined Silicon double quantum dot (QD) transistors. We show that our approach is compatible with very large scale integration, allowing for parallel fabrication of up to 144 scalable devices. HSQ process optimisation allowed for realisation of reproducible QD dimensions of 50 nm and tunnel junction down to 25 nm. We observed that 80% of the fabricated devices had dimensional variations of less than 5 nm. These are the smallest high density double QD transistors achieved to date. Single electron simulations combined with preliminary electrical characterisations justify the reliability of our device and process
Glargine as a Basal Insulin Supplement in Recovering Critically Ill Patients - An In Silico Study
Tight glycaemic control is now benefiting medical and surgical intensive care patients
by reducing complications associated with hyperglycaemia. Once patients leave this intensive
care environment, less acute wards do not continue to provide the same level of glycaemic
control. Main reason is that these less acute wards do not have the high levels of nursing
resources to provide the same level of glycaemic control. Therefore developments in protocols
that are less labour intensive are necessary. This study examines the use of insulin glargine
for basal supplement in recovering critically ill patients. These patients represent a group who
may benefit from such basal support therapy. In silico study results showed the potential in
reducing nursing effort with the use of glargine. However, a protocol using only glargine for
glucose control did not show to be effective in the simulated patients. This may be an indication
that a protocol using only glargine is more suitable after discharge from critical care
Fabrication of highly efficient grating band-pass filters and their applications in soliton propagation system
We report here fabrication of highly efficient in-fiber grating bandpass filters using the established UV-side- exposure technique. Various combinations of passband/stopband and transmission/rejection of single- and multi-channel filters have been produced in hydrogenated standard telecom, high Ge-doped and B/Ge-codoped fibers. Up to > 60 dB rejection stopbands ranging from -2 nm to 55 nm, and passbands with 0.02 nm - 3 nm linewidths and transmissivity up to > 90% have been achieved with these devices. By concatenating several structures, a bandpass filter has been demonstrated with a combination of a 0.16 nm passband centered in a approximately 35 nm stopband, representing the highest reported finesse of 220 for any multi-nanometer stopband filter. We also report the first application of a grating bandpass filter for suppressing timing jitter in soliton propagation system, enabling transmission of 10 ps solitons over a distance of 2700 km
The effect of bending loads on the dynamic behaviors of a rolling guide
Dynamic behaviors of ball-type contact surfaces under unbalanced bending loads are studied using point-to-point analysis, three-dimensional finite element simulation based on the Hertz Contact Theory, and a modal test. Results derived from these models are very similar but the Finite Element Model provides the best results since it allows for more elements of study, such as the steel ball, carriage, rail etc. In the study, results also show that frequencies vary slightly, but there is an obvious change in shapes. Therefore, the contact stiffness in simulations must be properly selected with the conclusion that different external loadings may affect the dynamic characteristics of such structures significantly
Focal Salvage MR Imaging–Guided Cryoablation for Localized Prostate Cancer Recurrence after Radiotherapy:12-Month Follow-up
Purpose: To evaluate safety, quality of life (QoL), and local cancer control after focal salvage MR imaging–guided cryoablation in patients with local recurrence of prostate cancer (PCa) after radiotherapy. Materials and Methods: A retrospective, single-center study was performed in 62 patients with radiorecurrent PCa who underwent MR imaging–guided cryoablation since May 2011 with a follow-up ≥12 months in December 2017. Rates and descriptions of adverse events were reported. Ablation complications were classified according to the Clavien and SIR systems. Validated questionnaires were used to observe functional outcomes and QoL before therapy and 6 and 12 months after therapy. Cancer control was defined as no biochemical failure according to Phoenix criteria and no other clinical evidence for local or metastatic disease. Results: All procedures were technically feasible. The number of complications requiring major therapy (Clavien grade 3b/4 or SIR grade D/E/F) was low (2 [3.2%] and 1 [1.6%], respectively). After 12 months, the International Consultation of Incontinence Questionnaire–Short Form (P < .001) and 5-item International Index of Erectile Function (P = .001) scores became significantly worse, indicating increased symptoms of incontinence and diminished erectile function, without compromising QoL. Six patients developed metastases within 6 months. After 12 months, 36 patients (63%) were disease-free. Conclusions: Focal salvage MR imaging–guided cryoablation is safe and is associated with a high technical success rate, preservation of QoL, and local PCa control. This treatment can be a reasonable alternative to salvage radical prostatectomy in properly selected patients with low morbidity and preservation of QoL; however, longer follow-up is needed
Two-neutron overlap functions for 6He from a microscopic structure model
A fully antisymmetrized microscopic model is developed for light two-neutron
halo nuclei using a hyper-spherical basis to describe halo regions. The
many-body wavefunction is optimized variationally. The model is applied to 6He
bound by semi realistic Minnesota nucleon-nucleon forces. The two-neutron
separation energy and the radius of the halo are reproduced in agreement with
experiment. Antisymmetrization effects between 4He and halo neutrons are found
to be crucial for binding of 6He. We also properly extract two-neutron overlap
functions and find that there is a significant increase of 30%-70% in their
normalization due to microscopic effects as compared to the results of
three-body models.Comment: To be published in Nucl. Phys.
Global weak solution and large-time behavior for the compressible flow of liquid crystals
The three-dimensional equations for the compressible flow of liquid crystals
are considered. An initial-boundary value problem is studied in a bounded
domain with large data. The existence and large-time behavior of a global weak
solution are established through a three-level approximation, energy estimates,
and weak convergence for the adiabatic exponent
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