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The excellent wall condition is essential for fusion devices to generate reproducible high-parameter plasma. Wall conditioning techniques should be validated before applying on large fusion devices to reduce potential risk. Helimak, a toroidal steady state magnetic confinement device, was reassembled and upgraded to a technical validation platform for wall conditioning. A new control system has been developed to achieve the upgrade of Helimak. The control system is based on a distributed control architecture, which provides not only efficient development but also flexible control mechanisms. For each auxiliary subsystem, a corresponding local control module is developed to drive and control a variety of equipment. The control network ensures real-time transmitting of the parameters and data. A dedicated trigger network and timing control module can improve synchronization and real-time performance. Data acquisition system based on mature commercial busses provides sufficient data acquisition capabilities for diagnostic tools. The data management system uses MDSplus to provide convenient data access. An independent interlock and safety system is designed for comprehensive and reliable personal protection. After engineering commissioning, the Helimak has realized wall conditioning by electron cyclotron resonance heating (ECRH) plasma at different resonance positions. The flexibility of control systems allows the installation of more wall conditioning tools in the future that will provide the ability to validate combined wall conditioning techniques. Helimak will become a low-cost, reliable technology verification platform, which will help to achieve advanced scenarios in tokamak and stellarator.

Tremendous efforts have been made to improve the electrochemical performance of the lithium-sulfur batteries. However, challenges remain in achieving fast electronic and ionic transport while accommodate the significant cathode volumetric change. On the other hand, the severe capacity decay mainly attributed to polysulfide shuttle also hampers the practical applications. Here, we report a simple, low-cost, and eco-friendly method for the one-step preparation of a binder-free S-C composite cathode by plasma dissociation of CS2 containing gases at room-temperature. The key issue of polysulfide shuttle effect in Li-S batteries is also effectively resolved just by the introduction of N2 into the precursor gases. The electrode exhibits a high reversible capacity of ~600 mAh/g of the total hybrid of S + C at 100 mA/g after 100 cycles with an excellent initial coulombic efficiency of nearly 100%. The cells also demonstrate along cycle life and an extremely high capacity of ~306 mAh/g even after 300 cycles at 1 A/g with a high coulombic efficiency of about 100%. The proposed method will open the way for the plasma applications in facile preparation of Li-S batteries and the improvement of its electrochemical performance.

The poloidal width of the filaments induced by the type-I edge localized mode has power dependence in EAST. The poloidal widths of the filaments observed by the high-speed vacuum ultraviolet (VUV) imaging system are proportional to the heating power and the ELM size. To understand this power dependence, the BOUT++ nonlinear simulations have been performed with the reconstructed equilibriums from the experimental measurements in this paper. The synthetic filament structures from BOUT++ nonlinear simulation match the experimental observations by the VUV imaging system. The BOUT++ nonlinear simulations also reproduce the power dependence of the filament widths and the ELM size. The filament width and the ELM size are inversely proportional to the toroidal mode number. The low-n mode has a broader radial and poloidal structure, which causes the larger filament width and ELM size. In the high input power case, the mode spectrum shifts to low-n, a result of increasing peeling drive. Besides, we found the β p in a higher input power case leads to a broader pedestal, expanding the radial mode structure of the peeling-ballooning mode.

In this paper, we reported a plasma-based modification of the graphite powders as an anode material in lithium ion batteries, resulting in a theoretical-limit exceeded capacity. N2+H2 plasma treatment conducted in a low-frequency inductively coupled plasma source causes significant modifications in the graphite powders, such as the nanostructured surface, more surface defects, and the slightly widened interplanar spacing. Especially, the plasma generated N atoms from N2 precursor gas were efficiently introduced into the lattice sites of graphite in various configurations of pyridinic N, pyrrolic N and quaterrary N. These modifications lead to a pronounced improvement of electrochemical performance of the graphite powders. The specific reversible capacity is as high as 444 mAh g−1 at 100 mA g−1 for 100 cycles. The higher-rate performance and long-circle stabilities are also significantly improved just by this plasma processing. The charge transfer resistance is consistently reduced in all the cases of N2, H2, and N2+H2 plasma treatments. The underlying mechanism is analyzed in combination with the plasma diagnostics method of optical emission spectrum.

The paper investigates the effect of pedestal turbulence, i.e. coherent mode (CM), on the divertor total particle flux, the particle flux distribution and heat flux distribution, and their decay lengths in the scrape-off layer (SOL) region on EAST tokamak. The experimental evidence indicates the coherence between the pedestal CM and the divertor particle flux fluctuation, which implies that the pedestal CM can affect the divertor plasma behavior. The increase of the particle flux decay length ( λ j s ) correlates with the density radial decay length (λ n,SOL) in the SOL region where the λ n,SOL is largely affected by the change of pedestal CM amplitude. A quantitative statistical analysis shows that the divertor total particle flux and λ j s in the SOL region increase with increasing amplitude of the electron density fluctuation and the electron temperature fluctuation induced by the pedestal CM. The temporal decay process of the total particle flux is interrupted by the appearance of CM at the pedestal. Meanwhile, the spatial distributions of the divertor particle flux and heat flux are enhanced when the pedestal CM appears, which are observed in both the upper single null and lower single null configurations.

The effect of the chemical component and microstructure, not to mention their facile modification, of the coating/wrapping carbon layer on the electrochemical performance of the Si/C composite anode in lithium ion batteries (LIBs) hasn’t been actively explored although Si/C has been recognized as one of the most promising route for the high energy density LIBs. Herein we propose a novel nitrogen-plasma doping route to modify the top carbon film in an elaborately constructed layered Si/C composite anode. The electrochemical performance, e.g., the initial coulombic efficiency (CE), cycle stability and specific capacity of the composite anode is drastically improved by this plasma processing due to the increased kinetics of lithium ions. By means of the appropriate adjustment of the N doping ratio and N chemical configuration in the carbon layer through a N2/H2 plasma processing, the lithium diffusion rate in the composite anode was memorably increased as the pseudocapacitance effects promoted. The optimized Si/C composite exhibits a high capacity of 1120.7 mA h g−1 and an initial CE of 80.8% at the current of 2 A g−1 after a long cycle of 1500, increasing by ~40% of specific capacity and ~29% of the initial CE.

The I-mode is a promising operation mode for fusion in the future, featuring high-temperature and low-density confinement, but the reason why the temperature and density are decoupled remains an important aspect to be explored. The experimental results from the experimental advanced superconducting tokamak (EAST) showed that the weakly coherent mode (WCM) is directly related to sustaining the I-mode and that the peak amplitude of the WCM is proportional to the temperature in the pedestal. Simulating the experimental data from EAST with the six-field model of BOUT++, we find a density perturbation close to the frequency of the WCM observed in the experiment. By testing all the physical terms in this model, we find that the density perturbation and particle transport are directly related to the drift Alfvén wave (DAW) mode. We also use the SymPIC program (Xiao et al Plasma Sci. Technol. 20 110501; Phys. Plasmas 22 112504; Plasma Sci. Technol. 23 055102) to simulate the same experimental data and find that the frequency range of the WCM is close to both experimental and BOUT++ results. Therefore, the WCM of the I-mode can be considered to be driven by the DAW, which helps improve the transport of the I-mode.

This paper experimentally and numerically investigates the nonlinear vibrations and dynamic snap-through behaviors of the bistable asymmetric carbon fiber-reinforced [90n/0n] composite laminated shallow shell. In the experimental research, in order to produce the dynamic snap-through phenomena, the center of a bistable asymmetric composite laminated shallow shell is clamped on an electromechanical shaker. The shaker provides the controlled frequency and amplitude of the foundation excitation. A laser displacement testing system collects the data of the vibration signals for the bistable asymmetric composite laminated shallow shell. A high-speed camera captures the steady-state vibrations of the bistable asymmetric composite laminated shallow shell. The experimental results demonstrate the influence of the structural parameters on the dynamic snap-through phenomena and nonlinear vibrations of the bistable asymmetric composite laminated shallow shell. The amplitude-frequency response curves are obtained by the experimental results. The bifurcation diagrams , phase portraits, time histories, power spectrums, and Poincare maps are obtained to experimentally and numerically illustrate the single-well periodic, chaotic and double-well chaotic vibrations of the bistable asymmetric composite laminated shallow shell under the center foundation excitation. In numerical research, ABAQUS/CAE is used to simulate the dynamic responses of the bistable asymmetric composite laminated shallow shell. The subspace iteration method is utilized to give the vibration modal analysis . The vibration modes in the experimental research are qualitatively consistent with the results of the ABAQUS numerical simulation. The phenomenon of the energy transfer from the high-order to low-order primary resonance is discovered. The results of the experiment and numerical simulation are well verified with each other.

The occurrence conditions of the metastable chaotic vibrations are firstly studied in the bistable asymmetric composite laminated square shallow shell under the foundation excitation. The metastable chaos is observed in the vibration experiments of the bistable asymmetric composite laminated square shallow shell. Based on the dynamic model of the bistable asymmetric composite laminated square shallow shell, the critical instability condition of the zero equilibrium point is analyzed in the bistable asymmetric composite laminated square shallow shell by using Jacobian matrix and Routh-Hurwitz criterion. We perform numerical simulations based on Runge-Kutta algorithm and the vibration experiments. A sufficient condition is found for the existence of the metastable chaos in the bistable asymmetric composite laminated square shallow shell. It is found that the zero equilibrium point of the bistable asymmetric composite laminated square shallow shell is unstable when the parametric excitation exceeds a specific critical value. The numerical results verify the theoretical analyses of the metastable chaos. It is demonstrated that the increase of the parametric excitation leads to the easier occurrence of the metastable chaos through observing the characteristics of the nonlinear dynamic behaviors of the system. Moreover, the existence of the metastable chaotic vibrations is confirmed in the bistable asymmetric composite laminated square shallow shell under the foundation excitation by using the vibration experiments. The large parametric excitation subjecting to the bistable asymmetric composite laminated square shallow shell is a key factor for the existence of the metastable chaos in the bistable asymmetric composite laminated square shallow shell under the foundation excitation.

Herein we propose a novel plasma-based route to synergistically modulate the microstructures of the current collectors of nickel foam and subsequently the Si/C composite active coatings, restraining the huge volume expansion of silicon anode materials during lithiation/delithiation in Lithium ion batteries. The nickel foam surface is tailored to form the temperature-dependent nanostructures by the Ar/H2-plasma. And a 3D Si/C nano-composite structure is constructed in combination of silicon via magnetron sputtering and carbon through the inductively coupled plasma vapor deposition (ICP-CVD). The plasma-activated nickel foam surface leads to the crystallization of the sputtered silicon, and the significantly increased surface area results in the increases of loading rate of Si/C composites (e.g., 75% @room temperature). The electrochemical performance, e.g., the specific capacity, cycle stability and the initial Coulombic efficiency of the composite anode is drastically improved by the plasma processing. The cauliflower-like Si/C composites on the Ar/H2-plasma modified nickel foam at 300 °C exhibits a high capacity of 1941.2 mA h g−1 at 0.1 A g−1 after 100 cycles, and 976 mA h g−1 at 1.6 A g−1 after 500 cycles, increasing by 3–7 times in terms of the current density when compared with the case without the plasma processing.

The effects of obesity on reproduction have been widely reported in humans and mice. The present study was designed to compare the reproductive performance of lean and fat chicken lines, divergently selected for abdominal fat content. The following parameters were determined and analyzed in the two lines: (1) reproductive traits, including age at first egg and total egg numbers from generations 14 to 18, absolute and relative testicular weights at 7, 14, 25, 30, 45 and 56 weeks of age, semen quality at 30, 45 and 56 weeks of age in generation 18, and fertility and hatchability from generations 14 to 18; (2) reproductive hormones at 7, 14, 25, 30, 45 and 56 weeks of age in generation 18; (3) and the relative mRNA abundance of genes involved in reproduction at 7, 14, 25, 30, 45 and 56 weeks of age in generation 18. In females, birds in the lean line laid more eggs from the first egg to 40 weeks of age than the birds in the fat line. In male broilers, the birds in the lean line had higher absolute and relative testicular weights at 7, 14 and 25 weeks of age, but lower absolute and relative testicular weights at 56 weeks of age than the birds in the fat line. Male birds in the lean line had greater sperm concentrations and larger numbers of motile and morphologically normal sperms at 30, 45 and 56 weeks of age than the birds in the fat line. Fertility and hatchability were also higher in the lean line than in the fat line. Significant differences in the plasma levels of reproductive hormones and the expression of reproduction-associated genes were also found at different ages in the lean and fat birds, in both males and females. These results suggest that reproductive performance is better in lean birds than in fat birds. In view of the unique divergent lines used in this study, these results imply that selecting for abdominal fat deposition negatively affects the reproductive performance of birds.

This paper theoretically and experimentally investigates the dynamic snap-through phenomena and the nonlinear vibrations of the bi-stable asymmetric laminated composite square panel under the foundation excitation. We propose a new method to describe the dynamic snap-through phenomena of the bi-stable asymmetric laminated composite square panel by using the time-varying principle curvatures. The boundary conditions of the bi-stable asymmetric laminated composite square panel are clamped at the center of the panel and free at four edges. The mode shapes are obtained by employing Rayleigh-Ritz method and Lagrangian multipliers method. According to the double curvature type of von-Karman nonlinear strain-displacement relations, the third-order shear deformation theory and Hamilton principle, the nonlinear partial differential governing equations of motion are derived for the bi-stable asymmetric laminated composite square panel. The nonlinear ordinary differential governing equation of motion is obtained by using Galerkin method. Numerical simulations are used to study the nonlinear vibrations and the dynamic snap-through phenomena of the bi-stable asymmetric laminated composite square panel including the effect of the structural damping by using the 4-order Runge-Kutta method. Analyzing the phase portrait and time history of the principle curvature, the dynamic snap-through phenomena of the bi-stable asymmetric laminated composite square panel are observed through changing the amplitude of the foundation excitation. The vibration experiments are also finished to find the dynamic snap-through phenomena and the nonlinear vibrations of the bi-stable asymmetric laminated composite square panel. It is known that the theoretical and the experimental results are the qualitative agreement and the experimental results provide a reference for the application of the bi-stable asymmetric laminated composite square panel in the aeronautic and mechanical engineering fields.

The general optimization design method, such as Simplex method and Powell method, etc., can determine the final optimum structure and electric parameters of an electron optical system from given electron optical properties, but it may land in a local minimum of the optimum search process. The Genetic Algorithms (GAs) is a novel direct search optimization method based on principles of natural selection and “survival of the fittest” from natural evolution. Through the “reproduction”, “crossover” and “mutation” iterative process, GAs can search the global optimum result. In this paper, we applied the GAs to optimize an electron emission system, a “triode” structure used in a projection display with high resolution and brightness. The optimal structure and corresponding electrical parameters with a criterion of minimum objective function value, crossover radius, have been searched and presented in this paper. The GAs, as a direct search method and an adaptive search technique, has significant advantage in the optimization design of electron optical systems.

System errors (such as sensor response, location, or gain/phase errors between channels) would greatly degrade the DBF performance because the array data did not match with the ideal model assumed. Dogan, Gonen, and Mendel (see IEEE Trans. on AES. vol.30, no.3, p.722-41, 1994, IEEE Trans. on SP, vol.43, no.5, p.1200-16, 1995 and Proc. of IEEE Interl. Conf. on ASSP, p.1908-11, 1995) proposed the blind beamforming method, it provided a new idea to obtain a better DBF performance. Liao, Guisheng et al. (see Journal of China Institute of Communications, vol.17, no.4, p.9-14, 1996) proposed a cumulant-based method to estimate the supperresolution DOA of the desired signals. This paper refers to the method to solve the blind DBF problem, and uses it in an experimental bistatic radar to achieve pulse chasing. Some results are showed, and compared with a conventional method GSO (Gram-Schmidt orthogonalization).