6,071 research outputs found
Development of basic theories and techniques for determining stresses in rotating turbine or compressor blades
A method for measuring in-plane displacement of a rotating structure by using two laser speckle photographs is described. From the displacement measurements one can calculate strains and stresses due to a centrifugal load. This technique involves making separate speckle photographs of a test model. One photograph is made with the model loaded (model is rotating); the second photograph is made with no load on the model (model is stationary). A sandwich is constructed from the two speckle photographs and data are recovered in a manner similar to that used with conventional speckle photography. The basic theory, experimental procedures of this method, and data analysis of a simple rotating specimen are described. In addition the measurement of in-plane surface displacement components of a deformed solid, and the application of the coupled laser speckle interferometry and boundary-integral solution technique to two dimensional elasticity problems are addressed
Feynman Rules in the Type III Natural Flavour-Conserving Two-Higgs Doublet Model
We consider a two Higgs-doublet model with symmetry, which implies a
rather than 0 relative phase between the vacuum expectation
values . The corresponding Feynman rules are derived
accordingly and the transformation of the Higgs fields from the weak to the
mass eigenstates includes not only an angle rotation but also a phase
transformation. In this model, both doublets couple to the same type of
fermions and the flavour-changing neutral currents are naturally suppressed. We
also demonstrate that the Type III natural flavour-conserving model is valid at
tree-level even when an explicit symmetry breaking perturbation is
introduced to get a reasonable CKM matrix. In the special case , as the ratio runs from 0 to ,
the dominant Yukawa coupling will change from the first two generations to the
third generation. In the Feynman rules, we also find that the charged Higgs
currents are explicitly left-right asymmetric. The ratios between the left- and
right-handed currents for the quarks in the same generations are estimated.Comment: 16 pages (figures not included), NCKU-HEP/93-1
Perceived stigmatisation of patients with mental illness and its psychosocial correlates: a prospective cohort study
Searching for Perfect Fluids: Quantum Viscosity in a Universal Fermi Gas
We measure the shear viscosity in a two-component Fermi gas of atoms, tuned
to a broad s-wave collisional (Feshbach) resonance. At resonance, the atoms
strongly interact and exhibit universal behavior, where the equilibrium
thermodynamic properties and the transport coefficients are universal functions
of the density and temperature . We present a new calibration of the
temperature as a function of global energy, which is directly measured from the
cloud profiles. Using the calibration, the trap-averaged shear viscosity in
units of is determined as a function of the reduced temperature at
the trap center, from nearly the ground state to the unitary two-body regime.
Low temperature data is obtained from the damping rate of the radial breathing
mode, while high temperature data is obtained from hydrodynamic expansion
measurements. We also show that the best fit to the high temperature expansion
data is obtained for a vanishing bulk viscosity. The measured trap-averaged
entropy per particle and shear viscosity are used to estimate the ratio of the
shear viscosity to the entropy density, which is compared that conjectured for
a perfect fluid.Comment: 20 pages, 10 figure
reentrance effect in normal-metal/superconducting hybrid loops
We have measured the transport properties of two mesoscopic hybrid loops
composed of a normal-metal arm and a superconducting arm. The samples differed
in the transmittance of the normal/superconducting interfaces. While the low
transmittance sample showed monotonic behavior in the low temperature
resistance, magnetoresistance and differential resistance, the high
transmittance sample showed reentrant behavior in all three measurements. This
reentrant behavior is due to coherent Andreev reflection at the
normal/superconducting interfaces. We compare the reentrance effect for the
three different measurements and discuss the results based on the theory of
quasiclassical Green's functions
Initial experience of dedicated breast PET imaging of ER+ breast cancers using [F-18]fluoroestradiol.
Dedicated breast positron emission tomography (dbPET) is an emerging technology with high sensitivity and spatial resolution that enables detection of sub-centimeter lesions and depiction of intratumoral heterogeneity. In this study, we report our initial experience with dbPET using [F-18]fluoroestradiol (FES) in assessing ER+ primary breast cancers. Six patients with >90% ER+ and HER2- breast cancers were imaged with dbPET and breast MRI. Two patients had ILC, three had IDC, and one had an unknown primary tumor. One ILC patient was treated with letrozole, and another patient with IDC was treated with neoadjuvant chemotherapy without endocrine treatment. In this small cohort, we observed FES uptake in ER+ primary breast tumors with specificity to ER demonstrated in a case with tamoxifen blockade. FES uptake in ILC had a diffused pattern compared to the distinct circumscribed pattern in IDC. In evaluating treatment response, the reduction of SUVmax was observed with residual disease in an ILC patient treated with letrozole, and an IDC patient treated with chemotherapy. Future study is critical to understand the change in FES SUVmax after endocrine therapy and to consider other tracer uptake metrics with SUVmax to describe ER-rich breast cancer. Limitations include variations of FES uptake in different ER+ breast cancer diseases and exclusion of posterior tissues and axillary regions. However, FES-dbPET has a high potential for clinical utility, especially in measuring response to neoadjuvant endocrine treatment. Further development to improve the field of view and studies with a larger cohort of ER+ breast cancer patients are warranted
Complex refractive index tunability of graphene at 1550 nm wavelength
This is the published version. Copyright 2015 American Institute of PhysicsThe complex refractive index of graphene fabricated using chemical vapor deposition is characterized at 1550 nm wavelength through the reflectivity measurement on a SiO2/Si substrate. The observed tunability of the complex reflective index as the function of gate electric voltage is in agreement with the prediction based on the Kubo formula
GEMS: The Size Evolution of Disk Galaxies
We combine HST imaging from the GEMS survey with photometric redshifts from
COMBO-17 to explore the evolution of disk-dominated galaxies since z<1.1. The
sample is comprised of all GEMS galaxies with Sersic indices n<2.5, derived
from fits to the galaxy images. We account fully for selection effects through
careful analysis of image simulations; we are limited by the depth of the
redshift and HST data to the study of galaxies with absolute magnitudes
M(V)10. We find strong evolution in
the magnitude-size scaling relation for galaxies with M(V)<-20, corresponding
to a brightening of 1 mag per sqarcsec in rest-frame V-band by z=1. Yet, disks
at a given absolute magnitude are bluer and have lower stellar mass-to-light
ratios at z=1 than at the present day. As a result, our findings indicate weak
or no evolution in the relation between stellar mass and effective disk size
for galaxies with log(M)>10 over the same time interval. This is strongly
inconsistent with the most naive theoretical expectation, in which disk size
scales in proportion to the halo virial radius, which would predict that disks
are a factor of two denser at fixed mass at z=1. The lack of evolution in the
stellar mass-size relation is consistent with an ``inside-out'' growth of
galaxy disks on average (galaxies increasing in size as they grow more
massive), although we cannot rule out more complex evolutionary scenarios.Comment: 22 pages, 16 figures, submitted to Ap
- …