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[en] The evolution of AR-NW12A into a multi-purpose end-station with optional high-pressure crystallography is described. The macromolecular crystallography (MX) beamline AR-NW12A is evolving from its original design of high-throughput crystallography to a multi-purpose end-station. Among the various options to be implemented, great efforts were made in making available high-pressure MX (HPMX) at the beamline. High-pressure molecular biophysics is a developing field that attracts the interest of a constantly growing scientific community. A plethora of activities can benefit from high pressure, and investigations have been performed on its applicability to study multimeric complex assemblies, compressibility of proteins and their crystals, macromolecules originating from extremophiles, or even the trapping of higher-energy conformers for molecules of biological interest. Recent studies using HPMX showed structural hydrostatic-pressure-induced changes in proteins. The conformational modifications could explain the enzymatic mechanism differences between proteins of the same family, living at different environmental pressures, as well as the initial steps in the pressure-denaturation process that have been attributed to water penetration into the protein interior. To facilitate further HPMX, while allowing access to various individualized set-ups and experiments, the AR-NW12A sample environment has been revisited. Altogether, the newly added implementations will bring a fresh breath of life to AR-NW12A and allow the MX community to experiment in a larger set of fields related to structural biology
[en] Highlights: • Several crystalline phases of thorium dichalcogenides are identified. • A series of structural and semiconductor-metal phase transitions are investigated. • The relationship of thermodynamic, mechanical and electronic properties among ThS2, ThSe2 and ThTe2 is studied. • The compounds become softer one after another from ThS2 to ThSe2 and then to ThTe2.
[en] Highlights: • Shear viscosity of SF6 has been modeled (from 225.18 to 473.15 K up to 51.21 MPa). • Physically based viscosity models using from 1 to 6 parameters yield good results. • Effective repulsive steepness of the SF6 potential is higher than expected. - Abstract: Three recent physically based models (Lennard-Jones, free volume, thermodynamic scaling) for representing the viscosity of sulfur hexafluoride (SF6) are discussed together with two models (friction theory and Enskog 2σ) that have been recently applied to this fluid. The experimental database employed for adjustment (1562 data points) considers a large temperature (225.18 to 473.15 K) and pressure intervals (0.0264 to 51.21 MPa). The absolute average deviation is 3.8% for the Lennard-Jones model (one parameter), 1.7% for the free volume model (three parameters) and 1.5% for the thermodynamic scaling model (six parameters). Thus, it is shown that when physically based approaches are employed, a limited number of parameters is sufficient to represent accurately the shear viscosity of SF6. Furthermore it has been confirmed, using the thermodynamic scaling approach, that the repulsive steepness of the SF6 interaction potential is higher than usually found for fluids composed by non polar spherical molecule
[en] Conclusions: • Responding to design needs, the DACSDALMA code has been improved. • The instability test data of 1 MW DWT-SG were used for code verification. The details will be presented shorty. • Under high pressure conditions of 20 MPa like JSFR-SG, the Advanced Technology Experiment Sodium (Na) Facility (AtheNa) is planned to run dynamic stability tests in the near future
[en] High-pressure in-situ neutron diffraction technology, which developed very quickly especially in advanced countries, has many unique technology advantages in many important fields over the range from based scientific researches to national security strategy. A reactor neutron source (China Mianyang Research Reactor, CMRR), which is one of the only three neutron sources for neutron scattering in China, was newly built and operated in our institute (China Academy of Engineering Physics, CAEP). Base on it, we have been developed and established high pressure extreme environment on our neutron diffraction spectrometer. The aim of our plan is to make the pressure up to 20 GPa, the temperature exceed 1500 K, as well as the sample size larger than 2 mm. By using a newly designed large-volume panoramic-type opposed anvil cell, we have been realized the high pressure condition of in-situ neutron diffraction up to 10 GPa recently. Details of the progress and the related researches by using high pressure in-situ neutron diffraction will be presented on the conference.
[en] Soft nanoimprint lithography (soft NIL) relies on a mechanical deformation of a resist by a patterned polymer used as a mold. Here, we report on the investigation of the nanopattern fidelity of the high pressure imprint process based on a perfluorinated polyether (PFPE) soft mold material. The perfluorinated polyether material was found to be well suited to transfer the mold pattern into the resist by a direct imprinting process at low cost. Moderate deformations of the polymer mold structures occurring during the high pressure imprint are systematically studied. Features of decreased size are found to be more sensitive to pattern distortions. An optimized pattern design with increased structure density and constant pattern ratio is developed to minimize deformation effects. Imprints performed on the basis of these design rules result in reduced deformations and repeal their size dependence. The improved pattern transfer, especially for small structural elements, turns the direct and cost-effective soft UV-NIL into an interesting technique also for patterning tasks in the lower nanometer range.
[en] Cold-cathodoluminiscence (CCL) images have unmasked relict cataclastic microstructures in marbles and calc-schists of the higher-pressure units of the Samaná complex. The grain size of the cataclastic microstructures always has a self-similar distribution of power law type, with a slope break at log (ri)=1.7. The large grain size fraction (1.7< log (ri)<2.4) is characterized by fractal dimension D2=2.43 in the calcite-microstructures of the Punta Balandra unit and D2=2.72 in the Santa Bárbara unit. Both D-values are within the usual range of the carbonate-cataclasites and they are significant with the linear correlation of R2 =0.95 and 0.93, respectively. However, the finer grain size fraction (0.9< log (ri)<1.7) is characterized by D1<1 and this grain-size distribution is beyond the fractal-range for pure cataclastic-fabric, even though it has better fit power-law distribution. Microstructures such as dissolution-surfaces, interpenetrated particles and the higher roundness and lower irregularity of the boundary grain from fine fraction indicate that dissolution-precipitation creep was dominant after cataclasis. Clast size and stress reduction after cataclasis and the high fluid pressure provided favourable conditions to allow dissolution-precipitation creep. Transition from cataclastic flow to dissolution-precipitation creep was scale-dependent and it tended to homogenize and reduce the finer grain size frac tion. Consequently, the slope break between D1 and D2 is interpreted as a record in the grain size distribution produced by a change in the dominant deformation mechanism.
[es]Imágenes de catodoluminiscencia fría (CCL) han revelado microestructuras cataclásticas relictas en mármoles y calco-esquistos de las unidades de más alta presión del complejo de Samaná. El tamaño de grano de estas microestructuras presenta una distribución auto-similar de tipo potencial con una ruptura de pendiente en log (ri)=1.7. La fracción de mayor tamaño (1.7< log (ri)<2.4) presenta una dimensión fractal D2=2.43 en las microestructuras de calcita de las muestras de la unidad de Punta Balandra y D2=2.72 en la unidad de Santa Bárbara. Ambos valores están dentro de los valores habituales de las cataclasitas carbonatadas y tienen ajustes lineales de R2 =0.95 y 0.93 respectivamente. Sin embargo, la fracción de tamaño fino (0.9< log (ri)<1.7) se caracteriza por D1<1, por debajo del rango fractal de las distribuciones de tamaño de grano para las fábricas cataclásticas puras, aun presentando un mejor ajuste. Microestructuras como superficies de disolución, cantos interpenetrados y el mayor redondeamiento y menor irregularidad en los bordes de grano de la fracción fina indican que el creep de disolución-precipitación dominó tras la cataclasis. La reducción del tamaño de grano, la caída de los esfuerzos diferenciales tras el proceso cataclástico y la alta presión de fluidos, proporcionaron unas condiciones favorables para el creep de dissolución-precipitación. La transición del flujo cataclástico al creep de disolución-precipitación fue escalo-dependiente y homogeneizó la fracción de grano fina. Consecuentemente, la ruptura de pendiente entre D1 y D2 es interpretada como un registro en la distribución de tamaños de grano producido por un cambio en el mecanismo de deformación dominante.
[en] Complete text of publication follows. In the primary coolant circuit of pressurized water reactors (PWR), water radiolysis occurs at high temperature (HT), 280-320 deg C, and high pressure (HP), 15.5 MPa. Few data are available in the literature on the role of HT-HP water radiolysis on the corrosion of metallic reactor components. The present approach uses an high energy ion beam to control the production of radiolytic species at the AISI316L/water interface in a HP-HT electrochemical cell working in the range [25 deg C, 0.1 MPa] - [300 deg C, 9 MPa]. The cell is designed to record the free potential of the AISI 316L/water interface mounted in line on the CEMHTI (CNRS Orleans) cyclotron delivering the ion beam. The free potential evolution is compared before, during and after irradiation. Results are reported where an aqueous solution ([B] = 1000 ppm, [Li] = 2 ppm, [H2(aq)] = 4.1 x 10-5 mol L-1 at 25 deg C) is used to model the PWR primary coolant circuit. The AISI 316L/water interfaces are irradiated at 300 deg C with high energy protons emerging at ∼22 MeV at the interface with a flux varying by four orders of magnitude, from 107 to 1011 H+, cm-2, s-1. The free potential evolution under irradiation has been recorded and seems to depend on the flux, but also on the ageing of the AISI 316L target at 300 deg C and/or under irradiation. The behavior of the free potential under irradiation is highly dependent on temperature and pressure. During the experiment, an hydrogen permeation probe allows the measurement of the hydrogen amount in the solution, introduced initially or produced through the radiolysis. It enables to investigate in situ the interaction between a major product of water radiolysis, the hydrogen, and an irradiated solid/liquid interface.
[en] Highlights: ► The elastic and thermodynamic properties of (Cr0.5V0.5)2GeC under high pressure and temperature are predicted by first-principles. ► The calculated c axis is always stiffer than the a axis, completely evidenced by the axial bulk modulus. ► The structural metastability within 300–600 GPa has been observed resulting from (C11–C12) other than C44. ► The shear components (GV, GR, GH) investigations predicted that GR behaves more similarities with that of (C11–C12). ► The effects of the pressure and temperature on the bonding nature and thermodynamic properties are also studied. - Abstract: The elastic and thermodynamic properties of (Cr0.5V0.5)2GeC under high pressure and temperature are predicted by first-principles. Our calculated c axis is always stiffer than a axis between 0 and 800 GPa, completely consistent with the sequence of the axial bulk moduli. The structural metastability between 300 and 600 GPa has been observed from the elastic softening (C11–C12) but not from C44. Of the three shear components (GV, GR, GH) investigations at higher pressure, only GR estimation behaves more similarities with (C11–C12), and no any shear component even GV has presented certain similarities with C44. The effects of the pressure and temperature on the bonding nature and thermodynamic properties are also studied.