2,374 research outputs found
Preparation and ferroelectric properties of (124)-oriented SrBi4Ti4O15 ferroelectric thin film on (110)-oriented LaNiO3 electrode
A (124)-oriented SrBi4Ti4O15 (SBTi) ferroelectric thin film with high volume
fraction of {\alpha}SBTi(124)=97% was obtained using a metal organic
decomposition process on SiO2/Si substrate coated by (110)-oriented LaNiO3
(LNO) thin film. The remanent polarization and coercive field for
(124)-oriented SBTi film are 12.1 {\mu}C/cm2 and 74 kV/cm, respectively. No
evident fatigue of (124)-oriented SBTi thin film can be observed after
1{\times}10e9 switching cycles. Besides, the (124)-oriented SBTi film can be
uniformly polarized over large areas using a piezoelectric-mode atomic force
microscope. Considering that the annealing temperature was 650{\deg}C and the
thickness of each deposited layer was merely 30 nm, a long-range epitaxial
relationship between SBTi(124) and LNO(110) facets was proposed. The epitaxial
relationship was demonstrated based on the crystal structures of SBTi and LNO.Comment: 11 pages, 4 figures, published in Journal of Materials Science:
Materials in Electronics (JMSE), 19 (2008), 1031-103
A UserâFriendly Workbook to Facilitate Rapid and Accurate Rare Earth Element Analyses by ICPâMS for Multispiked Samples
The rare earth elements (REEs) are widely used as geochemical tracers in the earth, planetary, and ocean sciences. Inductively coupled plasmaâmass spectrometry (ICPâMS) has become the method of choice to analyze REE concentrations because it can rapidly measure the entire REE spectrum at the same time. This Technical Report presents a userâfriendly "REE Calculation Workbook" in Microsoft Excel to be used for calculating REE abundances in samples equilibrated with a multielement REE spike. This Workbook can be conveniently used to calculate REE concentrations in natural samples for spiked and unspiked elements measured by ICPâMS. For the spiked elements, their concentrations are calculated using isotope dilution equations. Using these spiked elements as references, concentrations of the four monoâisotopic REE elements, and other REE elements that are treated as monoâisotopic elements (in our case, La and Lu), can be calculated. The REE Workbook can be easily set up for use with different REE spikes. Evaluation of our analytical quality using a quadrupole ICPâMS on 10âmlâsized seawater samples shows that our analyses are comparable to highâprecision thermal ionization mass spectrometry (TIMS) studies, with much less time spent processing and analyzing, and with the added advantages of determining monoâisotopic elements. An important result is the clear demonstration of enrichments in Gd and Er compared to neighboring elements in seawater samples. In addition, we compare and evaluate commonly used reference standards BCRâ1, PostâArchean Australian Shale (PAAS), and North American Shale Composite (NASC)
Probing Cosmic Strings with Satellite CMB measurements
We study the problem of searching for cosmic string signal patterns in the
present high resolution and high sensitivity observations of the Cosmic
Microwave Background (CMB). This article discusses a technique capable of
recognizing Kaiser-Stebbins effect signatures in total intensity anisotropy
maps, and shows that the biggest factor that produces confusion is represented
by the acoustic oscillation features of the scale comparable to the size of
horizon at recombination. Simulations show that the distribution of null
signals for pure Gaussian maps converges to a distribution, with
detectability threshold corresponding to a string induced step signal with an
amplitude of about 100 \muK which corresponds to a limit of roughly . We study the statistics of spurious detections caused by
extra-Galactic and Galactic foregrounds. For diffuse Galactic foregrounds,
which represents the dominant source of contamination, we derive sky masks
outlining the available region of the sky where the Galactic confusion is
sub-dominant, specializing our analysis to the case represented by the
frequency coverage and nominal sensitivity and resolution of the Planck
experiment.Comment: 14 pages, 3 figures, to be published in JCA
Ionizing radiation absorption of vascular surgeons during endovascular procedures
ObjectiveEndovascular procedures have become an integral part of a vascular surgeonâs practice. The exposure of surgeons to ionizing radiation and other safety issues have not been well studied. We investigated the radiation exposure of a team of vascular surgeons in an active endovascular unit and compared yearly dosages absorbed by various body parts among different surgeons. Patientsâ radiation exposure was also assessed.MethodsThe radiation absorption of a team of vascular surgeons was prospectively monitored in a 12-month period. During each endovascular procedure, the effective body, eye, and hand radiation doses of all participating surgeons were measured by mini-thermoluminescent dosimeters (TLD) attached at the chest level under a lead apron, at the forehead at eye level, and at the hand. The type of procedure, fluoroscopy machine, fluoroscopy time, and personal and operating theatre radiation protection devices used in each procedure were also recorded. One TLD was attached to the patientâs body near the operative site to measure the patientâs dose. The yearly effective body, eye, and hand dose were compared with the safety limits of radiation for occupational exposure recommended by the International Commission on Radiation Protection (ICRP). The radiation absorption of various body parts per minute of fluoroscopy was compared among different surgeons.ResultsA total of 149 consecutive endovascular procedures were performed, including 30 endovascular aortic repairs (EVAR), 58 arteriograms with and without embolization (AGM), and 61 percutaneous transluminal angioplasty and stent (PTA/S) procedures. The cumulative fluoroscopy time was 1132 minutes. The median yearly effective body, eye, and hand dose for the surgeons were 0.20 mSv (range, 0.13 to 0.27 mSv), 0.19 mSv (range, 0.10 to 0.33 mSv) and 0.99 mSv (0.29 to 1.84 mSv) respectively, which were well below the safety limits of the ICRP. The mean body, eye, and hand dose of the chief surgeon per procedure were highest for EVAR. A significant discrepancy was observed for the average hand dose per minute of fluoroscopy among different surgeons. The mean radiation absorption of patients who underwent EVAR, AGM, and PTA/S was 12.7 mSv, 13.6 mSv, and 3.4 mSv, respectively.ConclusionWith current radiation protection practice, the radiation absorbed by vascular surgeons with a high endovascular workload did not exceed the safety limits recommended by ICRP. Variations in practice, however, can result in significant discrepancy of radiation absorption between surgeons
Dynamics of a classical gas including dissipative and mean field effects
By means of a scaling ansatz, we investigate an approximated solution of the
Boltzmann-Vlasov equation for a classical gas. Within this framework, we derive
the frequencies and the damping of the collective oscillations of a
harmonically trapped gas and we investigate its expansion after release of the
trap. The method is well suited to studying the collisional effects taking
place in the system and in particular to discussing the crossover between the
hydrodynamic and the collisionless regimes. An explicit link between the
relaxation times relevant for the damping of the collective oscillations and
for the expansion is established.Comment: 4 pages, 1 figur
Exploring morphological correlations among H2CO, 12CO, MSX and continuum mappings
There are relatively few H2CO mappings of large-area giant molecular cloud
(GMCs). H2CO absorption lines are good tracers for low-temperature molecular
clouds towards star formation regions. Thus, the aim of the study was to
identify H2CO distributions in ambient molecular clouds. We investigated
morphologic relations among 6-cm continuum brightness temperature (CBT) data
and H2CO (111-110; Nanshan 25-m radio telescope), 12CO (1--0; 1.2-m CfA
telescope) and midcourse space experiment (MSX) data, and considered the impact
of background components on foreground clouds. We report simultaneous 6-cm H2CO
absorption lines and H110\alpha radio recombination line observations and give
several large-area mappings at 4.8 GHz toward W49 (50'\times50'), W3
(70'\times90'), DR21/W75 (60'\times90') and NGC2024/NGC2023 (50'\times100')
GMCs. By superimposing H2CO and 12CO contours onto the MSX color map, we can
compare correlations. The resolution for H2CO, 12CO and MSX data was about 10',
8' and 18.3", respectively. Comparison of H2CO and 12CO contours, 8.28-\mu m
MSX colorscale and CBT data revealed great morphological correlation in the
large area, although there are some discrepancies between 12CO and H2CO peaks
in small areas. The NGC2024/NGC2023 GMC is a large area of HII regions with a
high CBT, but a H2CO cloud to the north is possible against the cosmic
microwave background. A statistical diagram shows that 85.21% of H2CO
absorption lines are distributed in the intensity range from -1.0 to 0 Jy and
the \Delta V range from 1.206 to 5 km/s.Comment: 18 pages, 22 figures, 5 tables. Accepted to be published in
Astrophysics and Space Scienc
Approach to equilibrium for a class of random quantum models of infinite range
We consider random generalizations of a quantum model of infinite range
introduced by Emch and Radin. The generalization allows a neat extension from
the class of absolutely summable lattice potentials to the optimal class
of square summable potentials first considered by Khanin and Sinai and
generalised by van Enter and van Hemmen. The approach to equilibrium in the
case of a Gaussian distribution is proved to be faster than for a Bernoulli
distribution for both short-range and long-range lattice potentials. While
exponential decay to equilibrium is excluded in the nonrandom case, it is
proved to occur for both short and long range potentials for Gaussian
distributions, and for potentials of class in the Bernoulli case. Open
problems are discussed.Comment: 10 pages, no figures. This last version, to appear in J. Stat. Phys.,
corrects some minor errors and includes additional references and comments on
the relation to experiment
Morphology and Orientation Selection of Non-Metallic Inclusions in Electrified Molten Metal
The effect of electric current on morphology and orientation selection of non-metallic inclusions in molten metal has been investigated using theoretical modelling and numerical calculation. Two geometric factors, namely the circularity (fc) and alignment ratio (fe) were introduced to describe the inclusions shape and configuration. Electric current free energy was calculated and the values were used to determine the thermodynamic preference between different microstructures. Electric current promotes the development of inclusion along the current direction by either expatiating directional growth or enhancing directional agglomeration. Reconfiguration of the inclusions to reduce the system electric resistance drives the phenomena. The morphology and orientation selection follows the routine to reduce electric free energy. The numerical results are in agreement with our experimental observations
Perioperative sexual interest in women with suspected gynecologic malignancies
Objectives For women with gynecologic cancer, the impact of surgery on sexual interest and desire in the immediate and later postoperative period is not well characterized. The objective of this study was to report the perioperative trends of changing sexual interest and desire in a cohort of women undergoing surgery for suspected gynecologic malignancies. Methods This is an ancillary analysis of a cohort study analyzing health-related outcomes in women who underwent primary surgical management of a suspected gynecologic malignancy between 10/2013 and 10/2014. Subjects completed the Patient-Reported Outcomes Measurement Information System Sexual Function and Satisfaction Questionnaire (PROMIS-SFQ) preoperatively and questions on sexual interest and desire at one, three, and six months postoperatively. Bivariate tests and multiple linear regression were used to analyze data. Results Of 231 women who completed a baseline PROMIS-SFQ, 187 (81%) completed one-month, 170 (74%) three-month, and 174 (75%) six-month follow-up interviews. Following surgery, 71% of enrolled subjects were diagnosed with a malignancy. Women age 55 (â 5.5 ± 1.0 vs â 2.3 ± 0.9, p = 0.02). In a multivariable analysis, age < 55 remained associated with a larger decrease in sexual interest at one month postoperatively (â 4.6, 95% CI: â 1.8, â 7.4), as did having cancer vs benign disease for women of all ages (â 5.6, 95% CI: â 9.6, â 1.5). Conclusions This study provides new data regarding the timing and magnitude of changes in sexual interest following gynecologic oncology procedures
Sexual Health before Treatment in Women with Suspected Gynecologic Malignancy
Objectives: Sexual health in survivors of gynecologic cancer has been studied; however, sexual health in these women before treatment has not been thoroughly evaluated. The objective of our study was to describe the pretreatment characteristics of sexual health of women with suspected gynecologic cancer before cancer treatment. Materials and Methods: We performed a cross-sectional analysis of women with a suspected gynecologic cancer, who were prospectively enrolled in a hospital-based cancer survivorship cohort from August 2012 to June 2013. Subjects completed the validated Patient-Reported Outcomes Measurement Information System Sexual Function and Satisfaction Questionnaire. Pretreatment sexual health was assessed in terms of sexual interest, desire, lubrication, discomfort, orgasm, enjoyment, and satisfaction. Results: Of 186 eligible women with suspected gynecologic cancer, 154 (82%) completed the questionnaire pretreatment. Mean age was 58.1 ± 13.3 years. Sexual health was poor: 68.3% reported no sexual activity, and 54.7% had no interest in sexual activity. When comparing our study population to the general U.S. population, the mean pretreatment scores for the subdomains of lubrication and vaginal discomfort were similar, while sexual interest was significantly lower and global satisfaction was higher. In a linear regression model, controlling for cancer site, age remained significantly associated with sexual function while cancer site did not. Conclusions: Problems with sexual health are prevalent in women with suspected gynecologic malignancies before cancer treatment. Increasing awareness of the importance of sexual health in this population will improve quality of life for these women
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