3,185 research outputs found
Electric‐field‐induced optical rectification in nitrobenzene
The first observation of dc‐electric‐field‐induced$optical rectification is eported. In this process a dc polarization is produced in a medium (in this case nitrobenzene) by the simultaneous presence of dc and optical electric fields. The relation between this process and the Kerr effect is found to be consistent with that predicted by permutation symmetry. A bolometerlike response also seen in these experiments is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70898/2/APPLAB-30-6-276-1.pd
Collider Interplay for Supersymmetry, Higgs and Dark Matter
We discuss the potential impacts on the CMSSM of future LHC runs and possible
electron-positron and higher-energy proton-proton colliders, considering
searches for supersymmetry via MET events, precision electroweak physics, Higgs
measurements and dark matter searches. We validate and present estimates of the
physics reach for exclusion or discovery of supersymmetry via MET searches at
the LHC, which should cover the low-mass regions of the CMSSM parameter space
favoured in a recent global analysis. As we illustrate with a low-mass
benchmark point, a discovery would make possible accurate LHC measurements of
sparticle masses using the MT2 variable, which could be combined with
cross-section and other measurements to constrain the gluino, squark and stop
masses and hence the soft supersymmetry-breaking parameters m_0, m_{1/2} and
A_0 of the CMSSM. Slepton measurements at CLIC would enable m_0 and m_{1/2} to
be determined with high precision. If supersymmetry is indeed discovered in the
low-mass region, precision electroweak and Higgs measurements with a future
circular electron-positron collider (FCC-ee, also known as TLEP) combined with
LHC measurements would provide tests of the CMSSM at the loop level. If
supersymmetry is not discovered at the LHC, is likely to lie somewhere along a
focus-point, stop coannihilation strip or direct-channel A/H resonance funnel.
We discuss the prospects for discovering supersymmetry along these strips at a
future circular proton-proton collider such as FCC-hh. Illustrative benchmark
points on these strips indicate that also in this case FCC-ee could provide
tests of the CMSSM at the loop level.Comment: 47 pages, 26 figure
Noninvasive Evaluation of Portal Hypertension: Emerging Tools and Techniques
Portal hypertension is the main cause of complications in patients with cirrhosis. However, evaluating the development and progression of portal hypertension represents a challenge for clinicians. There has been considerable focus on the potential role of noninvasive markers of portal hypertension that could be used to stratify patients with respect to the stage of portal hypertension and to monitor disease progression or treatment response in a longitudinal manner without having to undertake repeated invasive assessment. The pathogenesis of portal hypertension is increasingly understood and emerging knowledge of the vascular processes that underpin portal hypertension has paved the way for exploring novel biomarkers of vascular injury, angiogenesis, and endothelial dysfunction. In this paper we focus on the pathogenesis of portal hypertension and potential non-invasive biomarkers with particular emphasis on serum analytes
Measurement and Modeling of Infrared Nonlinear Absorption Coefficients and Laser-induced Damage Thresholds in Ge and GaSb
Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al2O3 anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond pulses, respectively
Improved approximation algorithm for k-level UFL with penalties, a simplistic view on randomizing the scaling parameter
The state of the art in approximation algorithms for facility location
problems are complicated combinations of various techniques. In particular, the
currently best 1.488-approximation algorithm for the uncapacitated facility
location (UFL) problem by Shi Li is presented as a result of a non-trivial
randomization of a certain scaling parameter in the LP-rounding algorithm by
Chudak and Shmoys combined with a primal-dual algorithm of Jain et al. In this
paper we first give a simple interpretation of this randomization process in
terms of solving an aux- iliary (factor revealing) LP. Then, armed with this
simple view point, Abstract. we exercise the randomization on a more
complicated algorithm for the k-level version of the problem with penalties in
which the planner has the option to pay a penalty instead of connecting chosen
clients, which results in an improved approximation algorithm
Temperature dependent optical studies of TiCoO
We present the results of Raman and photoluminescence (PL) studies on
epitaxial anatase phase TiCoO films for = 0-0.07, grown by
pulsed laser deposition. The low doped system (=0.01 and 0.02) shows a Curie
temperature of ~700 K in the as-grown state. The Raman spectra from the doped
and undoped films confirm their anatase phase. The photoluminescence spectrum
is characterized by a broad emission from self-trapped excitons (STE) at 2.3 eV
at temperatures below 120 K. This peak is characteristic of the anatase-phase
TiO and shows a small blueshift with increasing doping concentration. In
addition to the emission from STE, the Co-doped samples show two emission lines
at 2.77 eV and 2.94 eV that are absent in the undoped film indicative of a
spin-flip energy.Comment: 8 pages, 4 figure
Unconstrained and Constrained Fault-Tolerant Resource Allocation
First, we study the Unconstrained Fault-Tolerant Resource Allocation (UFTRA)
problem (a.k.a. FTFA problem in \cite{shihongftfa}). In the problem, we are
given a set of sites equipped with an unconstrained number of facilities as
resources, and a set of clients with set as corresponding
connection requirements, where every facility belonging to the same site has an
identical opening (operating) cost and every client-facility pair has a
connection cost. The objective is to allocate facilities from sites to satisfy
at a minimum total cost. Next, we introduce the Constrained
Fault-Tolerant Resource Allocation (CFTRA) problem. It differs from UFTRA in
that the number of resources available at each site is limited by .
Both problems are practical extensions of the classical Fault-Tolerant Facility
Location (FTFL) problem \cite{Jain00FTFL}. For instance, their solutions
provide optimal resource allocation (w.r.t. enterprises) and leasing (w.r.t.
clients) strategies for the contemporary cloud platforms.
In this paper, we consider the metric version of the problems. For UFTRA with
uniform , we present a star-greedy algorithm. The algorithm
achieves the approximation ratio of 1.5186 after combining with the cost
scaling and greedy augmentation techniques similar to
\cite{Charikar051.7281.853,Mahdian021.52}, which significantly improves the
result of \cite{shihongftfa} using a phase-greedy algorithm. We also study the
capacitated extension of UFTRA and give a factor of 2.89. For CFTRA with
uniform , we slightly modify the algorithm to achieve
1.5186-approximation. For a more general version of CFTRA, we show that it is
reducible to FTFL using linear programming
Explosion Codas and Design Seismic Coefficient
In view of construction of structures in seismic zones like high dams, nuclear power plants etc., evaluation of ‘site dependent design seismic coefficient’ has been of paramount importance. It is thus necessary to assess correctly ‘amplification factor’ of ground motion due to surface geology during earthquakes. This ground amplification factor depends on ‘predominant period’ of site in addition to other factors according to Kanai and others. Though micro tremors have been utilized for estimation of predominant period of site, it has been shown that explosion generated codas could also be used to obtain ground amplification factor useful for estimation of probabilistic site dependent design seismic coefficient from response spectra of probable maximum earthquake magnitude estimated from seismic environment and assumed life of the structure
Study of different mortars used for soaking pit recuperators
Effective utilisation of waste heat by the use of recuperators system has become more and more imperative
due to the recent energy crisis. Although both the recuperator and regenerator are used to preheat air, the
co•efficient of heat transfer is higher in the recup-erators than that of regenerators (2,5-6.0 as compared to 1.5- 3.5 Btuift2/hr/°F.)1. A recuperator Is a device whereby heat is continuously transferred from hot waste gases to combustion air and thus preheating it. In many modern soaking pits, batch or continuous type reheating furnaces, ceramic recuperators are used for achieving very high preheat temperature. The efficiency of the ceramic
recuperative system depends upon the quality of the refra-ctory tube and the mortars used for jointing material
Modeling and Simulation of a TFET-Based Label-Free Biosensor with Enhanced Sensitivity
This study discusses the use of a triple material gate (TMG) junctionless tunnel field-effect transistor (JLTFET) as a biosensor to identify different protein molecules. Among the plethora of existing types of biosensors, FET/TFET-based devices are fully compatible with conventional integrated circuits. JLTFETs are preferred over TFETs and JLFETs because of their ease of fabrication and superior biosensing performance. Biomolecules are trapped by cavities etched across the gates. An analytical mathematical model of a TMG asymmetrical hetero-dielectric JLTFET biosensor is derived here for the first time. The TCAD simulator is used to examine the performance of a dielectrically modulated label-free biosensor. The voltage and current sensitivity of the device and the effects of the cavity size, bioanalyte electric charge, fill factor, and location on the performance of the biosensor are also investigated. The relative current sensitivity of the biosensor is found to be about 1013. Besides showing an enhanced sensitivity compared with other FET- and TFET-based biosensors, the device proves itself convenient for low-power applications, thus opening up numerous directions for future research and applications
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