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71.
All components of the elasticity tensors for OsSi (P213), OsSi2 (Cmca) and Os2Si3 (Pbcn and P-4c2) were computed by means of the stress–strain method in the framework of the density functional theory. The total energies and stress were calculated using density functional theory within the local density and conjugate gradient approximations. From the knowledge of the elastic constants, the Born stability criteria were discussed and the Debye approximation was used to evaluate the enthalpies of formation (ΔHf) of the different compounds. The ΔHf calculated at 298 K for OsSi is in correct agreement with the experimental data but for Os2Si3(Pbcn) ΔHf is 30 kJ/mol of atoms more exothermic than the measured one. Moreover, we have found that from 1200 K the P-4c2 phase of Os2Si3 is most stable from the energy point of view than the Pbcn structure. 相似文献
72.
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74.
Aging of the linear drain current during OFF stress on a N-type lateral drain extended MOS is shown to be induced by the amorphous silicon nitride Contact Etch Stop Layer (CESL). A design of experiment on its PECVD conditions enables to demonstrate that the higher its Si-rich composition or at least of its interface, the higher the degradation. Supported by TCAD simulations, we propose a charge displacement model in the CESL that leads to the depletion of the extended drain region during stress explaining the on-resistance increase monitored by the linear drain current. 相似文献
75.
Marina Banuta Isabelle Tarquini Benoit Gauvin 《Journal of Failure Analysis and Prevention》2008,8(5):426-430
A failure investigation was performed on a ball joint from an ATV front suspension system. The location of the fracture was
the bearing ball/stud interface, which is a fusion-welded joint, and occurred after approximately 20 h of field-testing. The
two parts are made out of carbon steel and were previously heat-treated. Many elongated MnS inclusions were found in the stud
material, and these inclusions were parallel to the symmetry axis. Even though these inclusions were not significantly sized,
their number was important. Macroscopic evidence showed that the joint failed in a ductile mode under centered tensile overload.
Microscopic examination showed that MnS orientation changed in the fusion joint area. The inclusions had been redirected during
the welding process and laid parallel to the fracture surface. This reorientation caused a significant decrease in the effective
cross section of the joint and overload fracture occurred. 相似文献
76.
Vincent Revéret Philippe André Michel Talvard Louis R. Rodriguez Olivier Boulade Eric Doumayrou Pascal Gallais Benoit Horeau Jean Le Pennec Michel Lortholary Jérome Martignac Patrick Agnèse 《Journal of Low Temperature Physics》2008,151(1-2):32-39
The Herschel Space Observatory will carry onboard a new kind of bolometric architecture for the PACS (Photodetector Array
Camera and Spectrometer) submillimeter photometer. These new generation CCD-like multiplexed bolometer arrays are buttable
and enable the conception of large fully sampled focal planes either for space or for ground-based telescopes. We present
here some development for ground-based applications in the context of the ARTEMIS (ARchitecture de bolomètres pour des TElescopes
sub-MIllimétriques au Sol) project. We have developed an electro-thermal numerical model that simulates the performances of
these semiconducting bolometers under specific ground-based conditions (different wavelengths and background powers for example).
This model permits to determine the optimal parameters for each condition and shows that the bolometers can be background
limited in each atmospheric transmission window between 200 and 450 microns. We also describe the optical system that provides
a high optical efficiency in each submillimeter atmospheric window. Astronomical observations made with a prototype on the
APEX telescope are presented. 相似文献
77.
Medeiros Sara Fernandes Isabel Fournier Benoit Nunes João Carlos Ramos Violeta 《Bulletin of Engineering Geology and the Environment》2021,80(12):8949-8960
Bulletin of Engineering Geology and the Environment - The alkali-silica reaction (ASR) is a chemical deterioration of concrete that involves reactive forms of silica. Volcanic glass is one of the... 相似文献
78.
Thioether Analogues of Disulfide‐Bridged Cyclic Peptides Targeting Death Receptor 5: Conformational Analysis,Dimerisation and Consequences for Receptor Activation
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Dr. Karolina Pulka‐Ziach Dr. Valeria Pavet Neila Chekkat Dr. Karine Estieu‐Gionnet Roman Rohac Dr. Marie‐Charlotte Lechner Dr. Cristian R. Smulski Dr. Gabrielle Zeder‐Lutz Dr. Danièle Altschuh Dr. Hinrich Gronemeyer Prof. Dr. Sylvie Fournel Dr. Benoit Odaert Dr. Gilles Guichard 《Chembiochem : a European journal of chemical biology》2015,16(2):293-301
Cyclic peptides containing redox‐stable thioether bridges might provide a useful alternative to disulfide‐bridged bioactive peptides. We report the effect of replacing the disulfide bridge with a lanthionine linkage in a 16‐mer cyclic peptide that binds to death receptor 5 (DR5, TRAIL‐R2). Upon covalent oligomerisation, the disulfide‐bridged peptide has previously shown similar behaviour to that of TNF‐related apoptosis inducing ligand (TRAIL), by selectively triggering the DR5 cell death pathway. The structural and biological properties of the DR5‐binding peptide and its desulfurised analogue were compared. Surface plasmon resonance (SPR) data suggest that these peptides bind DR5 with comparable affinities. The same holds true for dimeric versions of these peptides: the thioether is able to induce DR5‐mediated apoptosis of BJAB lymphoma and tumorigenic BJELR cells, albeit to a slightly lower extent compared to its disulfide homologue. NMR analysis revealed subtle variation in the conformations of the two peptides and suggests that the thioether peptide is slightly less folded than its disulfide homologue. These observations could account for the different capability of the two dimers to cluster DR5 receptors on the cell surface and to trigger apoptosis. Nevertheless, our results suggest that the thioether peptide is a potential candidate for evaluation in animal models. 相似文献
79.
The origin of this article is the quantification of productivity gains and the improvement in surface integrity seen for a recent titanium alloy that is seeing increasing use in the aeronautical industry. The Ti555–3 titanium alloy, which is starting to find greater application in the aeronautical field, exhibits certain difficulties in terms of machining. High Pressure Coolant (HPC) assisted turning consists of projecting a high pressure coolant jet between the chip and the tool. Comparisons are made between assisted turning using variable jet pressure and conventional turning (dry and classical lubrication). It is shown that it is possible to improve productivity by using HPC-assisted machining. The results highlight good chip fragmentation and a great improvement of tool life with HPC assistance. Surface integrity is also shown to be improved, through surface roughness parameters that decrease, and surface residual stresses that become more compressive. These effects have been attributed to the thermo-mechanical action of the coolant jet resulting in lower cutting forces, lower coefficient of friction and lower temperature in the cutting zone. 相似文献
80.
Role of predation by zooplankton in transport and fate of protozoan (oo)cysts in granular activated carbon filtration 总被引:3,自引:0,他引:3
The significance of zooplankton in the transport and fate of pathogenic organisms in drinking water is poorly understood, although many hints of the role of predation in the persistence of microorganisms through water treatment processes can be found in literature. The objective of this study was to assess the impact of predation by natural zooplankton on the transport and fate of protozoan (oo)cysts in granular activated carbon (GAC) filtration process. UV-irradiated unlabelled Cryptosporidium parvum and Giardia lamblia (oo)cysts were seeded into two pilot-scale GAC filtration columns operated under full-scale conditions. In a two-week period after seeding, a reduction of free (oo)cysts retained in the filter bed was observed. Zooplankton was isolated from the filter bed and effluent water on a 30 μm net before and during the two-week period after seeding; it was enumerated and identified. Rotifers, which are potential predators of (oo)cysts, accounted for the major part of the isolated zooplankton. Analytical methods were developed to detect (oo)cysts internalized in natural zooplankton isolated from the filter bed and effluent water. Sample sonication was optimized to disrupt zooplankton organisms and release internalized microorganisms. (Oo)cysts released from zooplankton after sonication were isolated by IMS and stained (EasyStain™) for microscopic counting. Both Cryptosporidium and Giardia (oo)cysts were detected in association with zooplankton in the filter bed samples as well as in the effluent of GAC filters. The results of this study suggest that predation by zooplankton can play a role in the remobilization of persistent pathogens such as Cryptosporidium and Giardia (oo)cysts retained in GAC filter beds, and consequently in the transmission of these pathogens in drinking water. 相似文献