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A new target design is presented to model high-energy radiative accretion shocks in polars. In this paper, we present the experimental results obtained on the GEKKO XII laser facility for the POLAR project. The experimental results are compared with 2D FCI2 simulations to characterize the dynamics and the structure of plasma flow before and after the collision. The good agreement between simulations and experimental data confirms the formation of a reverse shock where cooling losses start modifying the post-shock region. With the multi-material structure of the target, a hydrodynamic collimation is exhibited and a radiative structure coupled with the reverse shock is highlighted in both experimental data and simulations. The flexibility of the laser energy produced on GEKKO XII allowed us to produce high-velocity flows and study new and interesting radiation hydrodynamic regimes between those obtained on the LULI2000 and Orion laser facilities.
Scanning Thermal Microscopy measurements with a resistive microprobe electrically heated were performed for different probe temperatures, for probe free in air and in contact with various specimens. The measured relative difference of Joule power dissipated in the probe when tip is in contact with a sample and when it is free in air is studied for different magnitude of the electrical current that heats the probe. A variation of this signal, never outlined before, is observed. A predictive modeling is used to explain these results and identify from the experimental data the global thermal conductance of the probe-sample thermal exchange for experiments performed in ambient conditions.
We observe the heat flux exchanged by the hot tip of a scanning thermal microscope, which is an instrument based on the atomic force microscope. We first vary the pressure in order to analyze the impact on the hot tip temperature. Then the distance between the tip and a cold sample is varied down to few nanometers, in order to reach the ballistic regime. We observe the cooling of the tip due to the tip-sample heat flux and compare it to the current models in the literature.
Using classical molecular-dynamics simulations, we worked out a simple model of Ion Beam Assisted Deposition (IBAD) of silicon dioxide on an amorphous silica substrate, in view to in- vestigate the modifications of the structural and vibrational properties induced by medium-energy bombardment. Atoms are assumed to interact via the two- and three-body potential developed by Nakano et al.. Analysis of the films grown with increasing ratio, R, of medium-(30 eV) to low- (1 eV) kinetic energy SiO2 particles shows that the density rises rapidly, from 1.3 g/cm3 for R =0 to about 2.3 g/cm3 for R = 0.7. This effect can be associated primarily with structural changes occurring at an intermediate length scale (4-10 Å), as it manifests itself by changes in the so-called first sharp diffraction peak (FSDP), the finger-print of medium range order (MRO) in a-SiO2 glass [2, 3]. We found also that the densification results in a significant decrease of the number of “soft” vibrational modes, occurring in the 0.5-3.5 THz frequency range.
Barrier CMP can reduce the topography generated during Cu CMP. In case of selective barrier CMP slurry like 1:10:1, it is expected that the topography reduction could not exceed the Ta thickness. Some recent observations made at Fujimi show that the topography reduction can be twice larger than the Ta thickness without dielectric loss. This paper presents the chemical mechanical phenomenon that is responsible for this 40 to 50 nm topography reduction during barrier CMP. At the end of the Cu CMP, Ta is exposed to oxidizer. This process can oxidize an important part of the Ta barrier which becomes Ta2O5 according to Pourbaix diagram . Ta2O5 can be as much as 2.3X thicker than original Ta layer. This phenomenon explains why topography reduction can be twice higher than initial Ta thickness. This mechanism explains why after Cu CMP it is likely to have more than 30 nm dishing on copper lines. The last and more important consequence is that this reduces final topography and total copper metal loss at the same time by about 30 nm. Obviously very high selectivity Cu CMP slurry (Cu:Ta ∼ 1000:1) is necessary to have neither Ta erosion nor Ta2O5 erosion during copper CMP. High selectivity slurry is required during barrier CMP in order to reduce the loss of copper and Dielectric during Barrier CMP.
From October 1977 to May 1980, 243 stools collected in sedentary and semi-nomadic populations of the Ahaggar (Algerian Sahara) were examined using immunoelectronmicroscopy and tissue culture inoculation. Immunoelectron-microscopy revealed the presence of rotaviruses in 8, coronaviruses in 26, adenoviruses in 5 and small round viruses in 4. Enteroviruses were isolated in tissue culture from 24 stools.
Rotaviruses were present in the Ahaggar but were associated with little acute enteric disease. The high frequency of coronaviruses both in gastroenteritis patients and in patients without disease was surprising. The prevalence of enteroviruses in this hyperarid zone was similar to or higher than that found in noticeably more humid countries.
Further systematic bacterial, viral and parasitic examinations are required to clarify the role of the above viruses in the aetiology of gastroenteritis in this region.
This article presents current R&D activities at Observatoire de Paris – Laboratoire d'Etude du Rayonnement
et de la Matière en Astrophysique in the fields of low noise mixers and local oscillators for heterodyne instruments dedicated to astrophysics, planetology and the sciences of the atmosphere.
The ESA BepiColombo mission, scheduled for launch in 2013 with a two–satellite configuration, will represent an important step in the exploration of the Solar System and will contribute to fundamental physics. Among the main scientific objectives of this mission are the Radio Science Experiments: gravimetry and rotation of Mercury and tests of Einstein's theory of general relativity, to be achieved by the MPO (Mercury Planetary Orbiter) satellite. The ISA (Italian Spring Accelerometer) instrument will give a fundamental contribution to these experiments by providing a continuous measurement of the non–gravitational accelerations acting on the MPO. After a description of the mission, the rôle of the ISA accelerometer will be discussed, together with the current activity for its development.
This paper reports the development of an experiment (TEPEE/GReAT) to test the Equivalence Principle (EP) at a level of accuracy equal to 5 × 10-15, by means of a differential accelerometer free falling in a cryogenic vacuum capsule released from a stratospheric balloon. Such an accuracy requires resolving a very small signal out of the instrument's intrinsic noise and the noise associated with the instrument's motion. Imperfections in the construction of the detector introduce gravity gradient noise that it is possible to separate from the violation signal spinning the detector around an horizontal axis in order to have the EP violation signal and the gravity gradients one modulated at two different frequencies. Experimental results on prototype instruments showing high sensitivity and common mode rejection factor are shown.
The aim of this study was to compare cardiac output measurements of the non-invasive cardiac output and the pulmonary artery catheter during repeat surgery for hip replacement.
In this prospective observational study, patients undergoing repeat hip surgery who needed a pulmonary artery catheter were included. A standard protocol was followed for induction, endotracheal intubation and maintenance of anaesthesia (sufentanil, etomidate, sevoflurane, cisatracurium). After endotracheal intubation, the non-invasive cardiac output was connected and a pulmonary artery catheter was inserted. Data were collected every 3 min until patients were extubated.
Ten patients were included and 2455 points of comparison recorded. Cardiac output from the pulmonary artery catheter varied from 1.7 to 8.9 L min−1 (mean 4.1 L min−1) and the non-invasive cardiac output (using averaging mode) from 1.7 to 8.0 L min−1 (mean 3.7 L min−1). There was a significant correlation between them (P < 0.01; bias 0.3 L min−1; limits of agreement +1.9 and –2.5 L min−1), although these differed between patients.
The perioperative bias was small and the non-invasive cardiac output slightly underestimated cardiac output intraoperatively compared to the pulmonary artery catheter. The bias was smaller when mean cardiac output was below 3 L min−1. Core temperature between 34.4°C and 37.6°C had no influence on the differences.
The role of precursor stoichiometry and local firing environment on the microstructural development of sol-gel derived lead zirconate titanate (PZT) thin films was investigated. Typically, excess Pb is added to films to compensate for PbO volatilization during heat treatment. Here, it is shown that the use of stoichiometric precursors with either a PbO atmosphere powder or a PbO overcoat during the crystallization heat treatment is an attractive and viable alternative method for control of film stoichiometry. Using these approaches, we have fabricated single phase perovskite thin films with microstructures and electrical properties (Pr ∼ 36 μC/cm2 and Ec ∼ 45 kV /cm) comparable to those of films using optimized solution chemistries and excess Pb additions. The potential advantage of increasing PbO partial pressure, or activity, during firing versus excess Pb additions is discussed from the standpoint of a proposed crystallization scenario based on the kinetic competition between Pb loss and the nucleation and growth rates of the perovskite phase.
Investigation of the geographical distribution of schizophrenia and its relationship to socio-demographic factors is useful for planning services.
Individuals with schizophrenia (n=980) were identified by key informants within an inner London borough and point prevalence calculated for broad, Feighner and DSM–III–R schizophrenia. The distribution of cases was tested for significant variation using the Poisson process model. Regression models using the Jarman-8 score and its component variables were tested for their ability to predict the prevalence of schizophrenia.
A high point prevalence of schizophrenia (5.3 per 1000 resident population) was demonstrated. Case distribution showed a marked and significant variation associated with socio-demographic factors. The prediction of prevalence was more accurate for broad than for narrower definitions of schizophrenia; unemployment rate performed best.
Unemployment rates and Jarman-8 scores may provide crude estimates for resource allocation in planning mental health services, highlighting the need for additional services in deprived inner city areas.