Search

The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil. The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field. The Cu I spectral lines at wavelengths of 510.5541, 515.3235, and 521.8202 nm are detected and analyzed. The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as ∼31.4 ± 15.7 T at a laser intensity of ∼5.6 × 1015 W/cm2, which agrees well with measurements using a B-dot probe. Some other plasma parameters of the central plasma disk are also studied. The temperature is evaluated from the Cu I spectral line intensity ratio, while the electron density is estimated from the Stark broadening effect.

Recently generation of strong magnetic (B) fields has been demonstrated in capacitor coils heated by high power laser pulses [S. Fujioka et al., Sci. Rep. 3, 1170 (2013)]. This paper will present a direct measurement of B field generated with an open-ended coil target driven by a nanosecond laser pulse using ultrafast proton radiography. The radiographs are analyzed with particle-tracing simulations. The B field at the coil center is inferred to be ∼50 T at an irradiance of ∼5 × 1014 W·cm−2. The B field generation is attributed to the background cold electron flow pointing to the laser focal spot, where a target potential is induced due to the escape of energetic electrons.

The optimal condition of spray drying purified flavonoids extract from R. tomentosa berries was studied by response surface methodology. The optimized condition for microencapsulation was of maltodextrin to gum Arabic ratio 1 : 1.3, total solid content 27.4%, glycerol monostearate content 0.25%, and core to coating material ratio 3 : 7, resulting in EE 91.75%. Prepared at the optimized condition, the flavonoids extract microcapsules (FEMs) were irregularly spherical particles with low moisture content (3.27%), high solubility (92.35%), and high bulk density (0.346 g/cm3). DPPH radical scavenging activity of FEMs was not decreased after spray drying (P>0.05) and higher than those in citric acid and rutin at the same concentration. Moreover, FEMs effectively retarded the oxidation of fresh lard during the 10-day storage period compared with vitamin C, nonencapsulated flavonoids extract, and rutin. Therefore, FEMs produced at the optimized condition could be used as powder ingredients with antioxidant capacities.

One of the remarkable dynamic features of the Herbig–Haro (HH) object is its highly collimated propagation far away from the accretion disk. Different factors are proposed to give us a clearly physical explanation behind these fascinating phenomena, including magnetic field, radiation cooling, surrounding medium, and so on. Laboratory astrophysics, as a new complementary method of studying astrophysical issues, can provide an insight into these behaviors in a similar and controllable laboratory environment. Here we report the scaled laboratory experiments that a well-collimated radiative jet with high Mach number is successfully created to mimic the evolution of HH objects. According to our results, we find that the radiation cooling effect within the jet and the outer rare surrounding plasmas from the X-ray (>keV) photoionized target contribute to the jet collimation. The local nonuniform density structures along the collimated radiative jet axis are caused by the pressure competition between the inner jet and the outer plasmas. The corresponding simulations performed with radiation-hydrodynamic codes FLASH reveal how the radiative jet evolves. [ABSTRACT FROM AUTHOR]

A double-turn capacitor-coil is used to produce a magnetic field (38.5 T) and construct a topology of magnetic reconnection in a low-β (β < 1) plasma environment. The device is constructed with two metallic U-turn coils connecting two parallel metallic disks. High energy lasers are employed to ablate one disk spontaneously driving two currents in the two coils, which produces an interactive magnetic field topology. We demonstrated through experiments and numerical simulations that the reconnection process takes place between two non-uniform magnetic fields created by the coils, and that the plasma state and the associated magnetic topology in the process can be seen via the technology of the optical probe beam and the proton backlight. [ABSTRACT FROM AUTHOR]

A counter-streaming flow system is a test-bed to investigate the astrophysical collisionless shock (CS) formation in the laboratory. Electrostatic/electromagnetic instabilities, competitively growing in the system and exciting the CS formation, are sensitive to the flows parameters. One of the most important parameters is the velocity, determining what kind of instability contributes to the shock formation. Here we successfully measure the evolution of the counter-streaming flows within one shot using a multi-pulses imaging diagnostic technique. With the technique, the average velocity of the high-density-part () of the flow is directly measured to be of cm/s between 7 ns and 17 ns. Meanwhile, the average velocity of the low-density-part () can be estimated as cm/s. The experimental results show that a collisionless shock is formed during the low-density-part of the flow interacting with each other. [ABSTRACT FROM AUTHOR]

Potential–pOH diagrams of nickel are drawn at various temperatures to predict the reaction of nickel in a 4M lithium hydroxide solution. Based on these diagrams, the thermodynamic stability of each constituent of nickel in 4M LiOH solution at various temperatures is evaluated. The oxidation mechanism is studied based on the thermodynamic analysis and the oxidation proceeds in the following order: Ni, Ni(OH)2 or HNiO2 −, NiOOH·H2O, NiOOH, LiNiO2. The thermodynamic model is validated experimentally by the cyclic voltammogram method. [Copyright &y& Elsevier]

Performance of a hydrocyclone can be influenced by many factors, such as structural type, geometric parameters and operation parameters, among which the structural type plays a very important role. The separation principle of a typical hydrocyclone was introduced. Focused on a gas-liquid separation, numerical simulation of the typical hydrocyclone was carried out. The gas phase fraction distribution was analysed. It is shown that the separation effect was not satisfactory. A revising idea was thus proposed and developed step by step, so a new inner-cone hydrocyclone (ICH) was designed. The inner-cone structure was thought to provide a more stable flow field for phase separation. It functions like a gas carrier that is beneficial for radially separated gas congregating on and growing into larger gas bubbles. It also produces an upward pushing force to gas bubbles, so as to enhance the gas-liquid separation performance, although the ICH has lower inner tangential velocities than the typical hydrocyclone. Numerical simulation and experimental study verified the analysis. Pressure drop of the ICH is much lower than that of the typical hydrocyclone; and the ICH has a wider scope for the change of liquid split ratio or inlet gas-liquid ratio. Development of the ICH would provide a new thought for the design of other separators. [ABSTRACT FROM AUTHOR]

Nuclear fusion reactions are the most important processes in nature to power stars and produce new elements, and lie at the center of the understanding of nucleosynthesis in the universe. It is critically important to study the reactions in full plasma environments that are close to true astrophysical conditions. By using laser-driven counter-streaming collisionless plasmas, the fusion d+d→³He+n is studied in a Gamow-like window around 27 keV. The results give hints that astrophysical nuclear reaction yields can be modulated significantly by the self-generated electromagnetic fields and the collective motion of the plasma. This plasma-version minicollider may provide a novel tool for studies of astrophysics-interested nuclear reactions, as well as a useful tool to constrain the models of plasma colliding dynamic. [ABSTRACT FROM AUTHOR]