The unique properties of neutron, such as its sensitivity to light elements and isotope, its capability of detecting magnetic structures, and its high penetrating power, make neutron diffraction an almost perfect method for scattering investigation of various materials, such as energetic compounds, hydrous minerals, superconductors, and magnetic materials.Based on a newly built and operated neutron source at Mianyang (China Mianyang Research Reactor, CMRR), we have been able to establish and develop some high pressure in-situ neutron diffraction techniques.With our own developed large-volume panoramic-type opposed anvil cell, we are currently able to collect the in-situ neutron diffraction patterns under a high pressure beyond gigapascal, and by employing the tungsten carbide anvil and applying the loading force at 150kN, we compressed the iron sample of 6mm³ volume up to 5GPa and collected neutron diffraction patterns within a few hours.By optimizing and combining our techniques, or by using the diamond anvil cell, we can obtain a spectrum of in-situ neutron diffraction under pressures that may be extended to over 10GPa.

The structural and physical properties of liquids under extreme conditions are of great interest in the research of condensed matters, material science and earth science.Due to the absence of long range order, numerous great challenges are being faced in experimental and theoretical studies on liquid under extreme conditions.Our knowledge of the structural and physical properties of liquids under extreme conditions is very much limited compared with those crystals.In this paper, we summarized the latest technical advances and scientific discoveries in the study of the structure, density and viscosity of liquids under high pressures and at high temperatures, which may facilitate the investigation of the structural and physical properties of liquids in the years ahead.

In situ X-ray diffraction measurements for natural Fe-bearing and Fe-free Mg₂SiO₄ forsterite single-crystals ((Mg_1.83Fe_0.17)SiO₄ and Mg₂SiO₄) were performed with diamond anvil cell high-pressure device and synchrotron radiation X-ray diffraction at room temperature.The experimental results showed that no phase transition of two natural olivine single-crystals was observed within the upper highest pressure of 9.9GPa.The isothermal relationship of pressure and volume in the two kinds of crystals is well described by the second-order Birch-Murnaghan equation of state with the zero-pressure unit cell volume and zero-pressure bulk modulus of 0.2929(3)nm³ and 140(3)GPa for Fe-bearing forsterite and 0.2899(1)nm³ and 151(2)GPa for Fe-free forsterite, respectively.The linear compressibilities along a, b and c axes (k_a, k_b and k_c) are elastically anisotropic in the two kinds of forsterite and the anisotropy can be described as k_b>k_c>k_a.With the addition of iron into the crystals, the bulk velocity of olivine decreases and the difference between the two kinds of forsterite single-crystals is 5.2%.This result will be significant for the study of the composition of the earth's upper mantle and its elastic wave velocities.

Knowledge of the heat-transport properties of eclogite and basalt, which are the most important parts of the oceanic subduction zone, is essential for understanding the thermal regimes and the geodynamics subduction zone.Based on the pulse heating method, we conducted high pressure experiment, and measured thermal diffusivities of eclogite and basalt at 1.0 and 2.0GPa and 373-973K.The results show that the thermal diffusivity of both eclogite and basalt decreases with the increase of temperature, and that, at 1.0 GPa and room temperature (278K), the thermal diffusivity and thermal conductivity of eclogite are about 30% and 50% higher than that of basalt, respectively.In the depth profiles of the subduction plate, the low thermal conductivity of upper basalt hinders the heat exchange between the subduction plate and the surrounding mantle, so that the subduction plate remains cold, hard and brittle, which results in strain accumulation and eventually leads to rupture and earthquake.In the lower half of the subduction plate, the basalt-eclogite phase transition reduces the temperature difference between the subduction plate and surrounding environment, which is favorable for the local dynamic stability.

In this paper we studied the equation of state (EOS) of uranium using the first-principles.The calculation of ground states indicates that the α structure is the most stable phase.The EOS at finite temperatures was computed by the quantum molecular dynamics (QMD).Based on this, the Hugoniot data were calculated and compared with the experimental data and other theoretical results.When the pressure is below 100GPa, the QMD calculated results are in good agreement with the experimental data, while those from the calculation by the quotidian equation of state (QEOS) don't agree so well with the experimental results.

We developed an ultra-high-speed electro-optical framing camera using high precision and low aberration optical subdivision, high precision delay, ultra-fast microchannel plate (MCP) exposure shutter and CCD image data acquisition system, with its performance indicators as the following:its image spatial resolution is 36mm^-1, its frame size is 1600×1200, and it can capture eight images with the photography frequency of 2×10⁸ frame/s.Using this camera, we successfully obtained clear images of the luminescent process of the tungsten wire and the rupture process of the detonator.

In order to study the explosion properties of the aluminum foil explosive, a high-content aluminum foil explosive, obtained by mixing aluminum foil with RDX uniformly, was chosen and compared with aluminum powder explosive in underwater explosion.The difference of the major parameters, such as the peak pressure, the impulse, the specific shock wave energy, the specific bubble energy, and the specific explosion energy, were obtained by analyzing the pressure vs.time curves recorded at different distances.The results from this experiment suggest that the decay rate of the peak pressure of the aluminum foil explosive is slower than that of the aluminum powder explosive, and the impulse and specific shock wave energy from the two explosives nearly match each other.The specific bubble energy of the aluminum foil explosive is slightly greater than that of the aluminum particle explosive due to its smaller specific surface area with high purity of aluminum and the longer bubble pulsation period of the aluminum foil explosive, so that the total energy of the aluminum foil explosive is slightly greater than that of the aluminum powder explosive.

A numerical calculation was carried out for the accelerated combined flyers by colliding explosive waves initiated by two symmetrical detonation initiators.In the calculation, Steinberg-Guinan (SG) strength model was used for the flyers to describe dynamic behaviors.From the calculation, the flying process and wave-propagating images were obtained.The results from our calculation are consistent with those from our actual measurements, demonstrating that the SG strength model is suitable for the combined flyers loaded with two head-on colliding explosive waves.This work lays a foundation for the study of suitability of the strength model at high strain rates and will serve as valuable reference for better understanding materials' constitutive relations and their dynamic behaviors in the colliding area.

Mach reflection in C₂H₂+2.5O₂+8.17Ar and C₂H₂+5N₂O over different wedge angles was experimentally investigated in a rectangular channel.In the experiments, the cellular transition structure surrounding wedges was recorded using smoked foils and unstable characteristics of the detonation front were captured using Schlieren setup.The results illustrate that for either a stable or an unstable mixture, there is a transition process of the cellular structure from the CJ zone to the overdriven zone.According to the experimental relationship between θ_w+χ and θ_w, the slope of the trajectory of the triple point (χ) formed by the Mach reflection increases with the wedge angle θ_w, which shortens the intersecting distance with trajectories of the triple points from the CJ zone and elevates the overdriven degree.In addition, the value of χ is significantly affected by the initial pressure and the wedge angle.The instability of C₂H₂+5N₂O is higher than that of C₂H₂+2.5O₂+8.17Ar, which accounts for markedly different behaviours of the Mach reflection that occurred in both mixtures.

Given the mono-temperature model and tri-temperature model as the two radiation-magneto-hydrodynamic models in the physical process of the Z-pinch, it is useful to understand the difference between the two models for a better use of these tools.In this paper the difference between the two models in the process of modeling is explained and three calculating models are designed to study the calculation difference resulting from the two models.The simulation results achieved show that the tri-temperature model has a faster spindle-touching speed, which is more obvious in low-temperature and heavy loads.The research by taking into account the physical reality shows that the difference between the two models is mainly caused by the equation of state (EOS):at low temperatures, there is a significant difference between atomic EOS and ionic EOS, hence the loaded surface has an uneven inflation, which eventually leads to the difference of the received kinetic energy; at high temperatures, this difference is reduced.Moreover, the EOS makes it more apt for impulse waves to be formed in the tri-temperature program than in the mono-temperature program and for the pioneering plasma to be formed as well.However, the calculation difference caused by the kinetic energy plays a major role.

A series of poly (3-hexylthiophene)(P3HT)/[6, 6]-phenyl-C₆₁ butyric acid methyl ester (PCBM) bulk heterojunction polymer solar cells were fabricated via a simple method, i.e.applying an external magnetic field on the active layer in its annealing process, which is based on the magnetic field effect on the alignment of the active layer's molecules.The experimental results demonstrate that the maximum photoelectric conversion efficiency (PCE) of 2.562% is achieved when the magnetic intensity is 0.9MA/m.The short-circuit current density is raised from 7.414mA/cm² to 8.332mA/cm², and the fill factor from 0.512% to 0.543%, but the open-circuit voltage almost remains the same.As characterized by the photoluminescence spectrum and atomic force microscope (AFM), the magnetic field had obvious effects on the molecular alignment and the crystallinity of the active layer and the surface morphology of film.

Fresh fruit and vegetable juice called not-from-concentrate (NFC) juice is rich in vitamin C, polyphenols and other active substances.Ultra-high pressure homogenization (UHPH) technique (that may reach up to 400MPa), a newly developed non-thermal processing technique based on the traditional homogenization method, can effectively inactivate microorganism and enzyme at room or lower temperature, and significantly preserve the original quality of the fruit and vegetable juice processed.In the present work we reviewed the latest developments in the study of the effects of UHPH on the quality and inactivation of microorganisms and enzymes of NFC juice and discussed the prospect of UHPH in NFC juice.