10,812 research outputs found
A Study on Correlations Between the Initial Optical and Scintillation Properties and Their Radiation Damage for Lead Tungstate Crystals
This paper presents a study of correlations between the initial optical and scintillation properties and their radiation damage for mass produced lead tungstate crystals. A correlation was observed between crystal's initial light outputs and the values of its initial longitudinal transmittance at 360 nm. A strong correlation was found between the emission weighted radiation induced absorption coefficients and the relative losses of the longitudinal transmittance at 440 nm. Correlations were also observed between the relative losses of crystal's light output and the relative losses of its longitudinal transmittance at 440 nm, or the emission weighted radiation induced absorption coefficients. No correlations were observed between crystal's radiation hardness and its initial longitudinal transmittance or the slope of the initial longitudinal transmittance across the band edge
A Radiation Damage and Recovery Study for Lead Tungstate Crystals from BTCP and SIC
This paper presents result of a study on radiation damage and recovery for lead tungstate
crystals produced at BTCP and SIC. Correlations were observed between initial light output and
initial longitudinal transmittance at 360 nm, between the loss of longitudinal transmittance at 440
nm and the loss of light output, and between radiation damages levels at different dose rates. No
correlations, however, were found between crystal’s initial optical properties and radiation hardness.
Excellent linearity was observed between the variations of crystal’s light output and its longitudinal
transmittance at 440 nm in several cycles of irradiation followed by recovery, indicating these PWO
crystals can be monitored in situ at LHC
Absorption and scattering of a high dimensional noncommutative black hole
In this work, we investigate the scattering of massless plane scalar waves by
the high dimensional noncommutative Schwarzschild-Tangherlini black hole. We
use the partial wave approach to determine the scattering and absorption cross
sections in the incident wavelength range. Our numerical results demonstrate
that the bigger the noncommutative parameter, the smaller the maximum value of
the related partial absorption cross section, however the tendency is slightly.
We also discovered that when the noncommutative parameter is weak, the
absorption cross section of the high dimensional black hole oscillates in the
low frequency zone. The total absorption cross section oscillates around the
geometrical optical limit in the high frequency range, and the scattering
characteristics of black holes with various parameters are visibly different.
The influence on the differential scattering cross section is particularly
pronounced at large angles.Comment: 10 pages and 4 figure
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Garlic Consumption and All-Cause Mortality among Chinese Oldest-Old Individuals: A Population-Based Cohort Study.
In vitro and in vivo experimental studies have shown garlic has protective effects on the aging process; however, there is no evidence that garlic consumption is associated with all-cause mortality among oldest-old individuals (≥80 years). From 1998 to 2011, 27,437 oldest-old participants (mean age: 92.9 years) were recruited from 23 provinces in China. The frequencies of garlic consumption at baseline and at age 60 were collected. Cox proportional hazards models adjusted for potential covariates were constructed to estimate hazard ratios (HRs) relating garlic consumption to all-cause mortality. Among 92,505 person-years of follow-up from baseline to September 1, 2014, 22,321 participants died. Participants who often (≥5 times/week) or occasionally (1-4 times/week) consumed garlic survived longer than those who rarely (less than once/week) consumed it (p < 0.001). Participants who consumed garlic occasionally or often had a lower risk for mortality than those who rarely consumed garlic at baseline; the adjusted HRs for mortality were 0.92(0.89-0.94) and 0.89(0.85-0.92), respectively. The inverse associations between garlic consumption and all-cause mortality were robust in sensitivity analyses and subgroup analyses. In this study, habitual consumption of garlic was associated with a lower all-cause mortality risk; this advocates further investigation into garlic consumption for promoting longevity
Bicuspid aortic stenosis in transcatheter aortic valve replacement era: Emerging confusions hindering the standardization of the procedure
Empirical metallicity-dependent calibrations of effective temperature against colours for dwarfs and giants based on interferometric data
We present empirical metallicity-dependent calibrations of effective
temperature against colours for dwarfs of luminosity classes IV and V and for
giants of luminosity classes II and III, based on a collection from the
literature of about two hundred nearby stars with direct effective temperature
measurements of better than 2.5 per cent. The calibrations are valid for an
effective temperature range 3,100 - 10,000 K for dwarfs of spectral types M5 to
A0 and 3,100 - 5,700 K for giants of spectral types K5 to G5. A total of
twenty-one colours for dwarfs and eighteen colours for giants of bands of four
photometric systems, i.e. the Johnson (), the Cousins
(), the Sloan Digital Sky Survey (SDSS, ) and the Two
Micron All Sky Survey (2MASS, ), have been calibrated. Restricted
by the metallicity range of the current sample, the calibrations are mainly
applicable for disk stars ([Fe/H]). The normalized percentage
residuals of the calibrations are typically 2.0 and 1.5 per cent for dwarfs and
giants, respectively. Some systematic discrepancies at various levels are found
between the current scales and those available in the literature (e.g. those
based on the infrared flux method IRFM or spectroscopy). Based on the current
calibrations, we have re-determined the colours of the Sun. We have also
investigated the systematic errors in effective temperatures yielded by the
current on-going large scale low- to intermediate-resolution stellar
spectroscopic surveys. We show that the calibration of colour ()
presented in the current work provides an invaluable tool for the estimation of
stellar effective temperature for those on-going or upcoming surveys.Comment: 28 pages, 19 figures, 8 tables, accepted for publication in MNRA
A Study on Radiation Damage in Large Size LSO and LYSO Crystal Samples
This paper presents a study on radiation damage
effect in large size (2.5×2.5×20 cm^3) LSO and LYSO crystals.
Optical and scintillation properties, including the longitudinal
transmittance and emission spectra, the light output and light
response uniformity with PMT and APD readout, are measured
before and after γ-ray irradiations with integrated dosage up to
106 rad for three LSO and LYSO samples from different vendors.
It was found that the recovery of radiation damage under room
temperature is negligible, indicating that radiation damage in LSO
and LYSO crystals are not dose rate dependent. It was also found
that the overall radiation damage in LSO and LYSO crystals is
small as compared to other crystal scintillators commonly used in
high energy and nuclear physics experiments
Seasonal variations in the Sr-Nd isotopic compositions of suspended particulate matter in the lower Changjiang River: Provenance and erosion constraints
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