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Plasma position and shape parameters are essential for equilibrium control and physics analysis in a tokamak. Such information is often obtained via optical boundary analysis. In this study, a new analysis of the visible image histogram of a high-speed high-resolution camera is presented which can effectively distinguish between the foreground information (showing the plasma of interest) and the background information (showing the inside views of the vacuum vessel wall and flanges, and so on). Using this method, we can obtain a reasonable approximation to the plasma boundary close to the last closed flux surface (LCFS) where plasma brightness contrast is greatest. The reliability and accuracy of this method are checked by comparing it favorably with other algorithms for different plasma shapes. The method is successfully tested also when the outboard plasma boundary oscillates in time with a magnitude of 10%. [ABSTRACT FROM AUTHOR]

To help reveal the complete picture of linear kinetic drift modes, four independent numerical approaches, based on the integral equation, Euler initial value simulation, Euler matrix eigenvalue solution and Lagrangian particle simulation, respectively, are used to solve the linear gyrokinetic electrostatic drift mode equation in Z-pinch with slab simplification and in tokamak with a ballooning space coordinate. We identify that these approaches can yield the same solution with the difference smaller than 1% and the discrepancies mainly come from the numerical convergence, which is the first detailed benchmark of four independent numerical approaches for gyrokinetic linear drift modes. Using these approaches, we find that the entropy mode and interchange mode are on the same branch in Z-pinch, and the entropy mode can have both electron and ion branches. And at a strong gradient, more than one eigenstate of the ion temperature gradient mode (ITG) can be unstable and the most unstable one can be on non-ground eigenstates. The propagation of ITGs from ion to electron diamagnetic direction at strong gradient is also observed, which implies that the propagation direction is not a decisive criterion for the experimental diagnosis of turbulent mode at the edge plasmas. [ABSTRACT FROM AUTHOR]

A series of CoxMn0.06/SiO2 catalysts, which were used for the synthesis of light hydrocarbons from CO hydrogenation, were prepared. The effects of reaction temperature, the morphological and structural properties of the catalysts on the CO conversion and product selectivity were examined. The results show that both CO conversion and C2 to C4 hydrocarbon selectivity are significantly affected by the amount of Co loaded onto the catalysts. The optimum Co content was determined to be 10 wt% (i.e., for Co0.10Mn0.06/SiO2) catalyst, and corresponding CO conversion and the selectivity to C2 to C4 hydrocarbons are 95.3 and 80.6%, respectively, at 400°C. [ABSTRACT FROM AUTHOR]

The influence of water stress on the absorptions and translocation of 14C-labelled fenoxapropethyl and imazamethabenz-methyl in Avena fatua L. (wild oat) was studied. The phytotoxicity to A. fatua of both herbicides with a droplet application was also examined under water stress conditions. The absorption of both fenoxapropethyl and imazamethabenz-methyl was reduced by water stress when the plants were harvested within 24 h after herbicide application. Up to 48 h after the application, the translocation out of the treated lamina of both herbicides, based on percentage of applied 14C, was reduced under water stress conditions. When harvested 96 h after herbicide application, however, water stress no longer significantly affected the absorption and translocation of either herbicide. When the herbicides were applied as individual droplets, water stress reduced the phytotoxicity of fenox-aprop-ethyl but not that of imazamethabenz-methyl. It is concluded that the changes in herbicide absorption and translocation may not be the major physiological processes associated with differential whole-plant response of A. fauna to fenoxaprop-ethyl and imazamethabenz-methyl under water stress. [ABSTRACT FROM AUTHOR]

In this paper, the ZTC4/B/C titanium matrix composite containing 0·2-0·5 wt-%B and 0·5-2 wt-%C was fabricated using melting-casting process. The microstructure and mechanical properties of as cast ZTC4/B/C Ti matrix composite were investigated. The results indicate that the microstructures of as cast ZTC4/B/C were consisted of lamellar α, β at grain boundary and second phases of bar-like TiB and spherical-like TiC. The elastic modulus of ZTC4/B with 0·5 wt-%B is 145 GPa, 30% higher than that of the matrix alloy. The ultimate tensile strength of ZTC4/B/C with 0·5 wt-%B and 0·5 wt-%C reached 1300 MPa, 25% higher than that of the matrix alloy. [ABSTRACT FROM AUTHOR]

First principles gyrokinetic simulation of the edge turbulent transport in toroidal plasmas finds a reverse trend in the turbulent transport coefficients under strong gradients. It is found that there exist both linear and nonlinear critical gradients for the nonmonotonicity of transport characteristics. The discontinuity of the transport flux slope around the turning gradient shows features of a second order phase transition. Under a strong gradient the most unstable modes are in nonground eigenstates with unconventional mode structures, which significantly reduces the effective correlation length and thus reverse the transport trend. Our results suggest a completely new mechanism for the low to high confinement mode transition without invoking shear flow or zonal flow. [ABSTRACT FROM AUTHOR]

Three electroslag remelting heats were carried out by using a 1-ton argon atmosphere ESR furnace under three kinds of slag containing different Ce2O3 content. Specimens were taken at electrode and each ingot for analyzing the inclusions by scanning electron microscope - energy dispersive spectrometer (SEM-EDS). After heat treatment, the tensile and impact of each steel product was measured to study the effect of Ce content on steel performance. The results show that the non-metallic inclusions content was largely reduced in each ingot compared with that in electrode, and the ingot containing 0,05 % Ce has the best steel cleanliness and performance, while the ingot containing 0,13 % Ce has the worst steel cleanliness and performance. [ABSTRACT FROM AUTHOR]

Experimental observation and theoretical analysis are presented for the nonlinear mode couplings between shear Alfvén wave and magnetic island. In the sub-Alfvén frequency range, two kind axi-symmetry magnetic activities with n = 0 have been observed during NBI on HL-2A. One kind has been identified, and belongs to EGAM. Another kind is found for the first time, its frequency lies in the range of TAE frequency. The Fourier bicoherence analysis suggests these axi-symmetry modes are generated by the nonlinear mode coupling via the decay process between Alfvén eigenmodes and low-frequency MHD modes. The experimental results indicate that the nonlinear mode coupling is one of mechanisms of the energy cascade in energetic-particle turbulence or Alfvén turbulence. [ABSTRACT FROM AUTHOR]

An intrinsic plastic Cu(45)Zr(46)Al(7)Ti(2) bulk metallic glass (BMG) with high strength and superior compressive plastic strain of up to 32.5% was successfully fabricated by copper mold casting. The superior compressive plastic strain was attributed to a large amount of randomly distributed free volume induced by Ti minor alloying, which results in extensive shear band formation, branching, interaction and self-healing of minor cracks. The mechanism of plasticity presented here suggests that the creation of a large amount of free volume in BMGs by minor alloying or other methods might be a promising new way to enhance the plasticity of BMGs.