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In this study, two homogeneous chitin and chitosan hexamers and one partially acetylated chitosan hexamer were used to investigate the degree of acetylation (DA) effects of chitooligosaccharides on the growth and photosynthesis of wheat seedlings. Both chitin and chitosan hexamers showed a significant promoting effect on the growth and photosynthesis of wheat seedlings but the positive effect depended on their DA. The homogeneous chitosan hexamers [(GlcN)6] exhibited the optimal activity compared to other samples. Seven days after (GlcN)6 treatment, the growth parameters of wheat seedlings were all significantly enhanced including fresh mass, dry mass, and length of both shoots and roots, and the contents of soluble sugar were increased by 22.8%. Additionally, (GlcN)6 could significantly promote (by 90.0%) the photosynthetic rate of wheat seedlings. Both Rubisco and fructose-1,6-bisphosphatase activity of photosynthetic carbon metabolism was also found to be significantly improved by (GlcN)6 treatment.

On the basis of the specific complexity, ambiguity and uncertainty of the selection of construction scheme for multi-attribute decision making system, a new evaluation method based on catastrophe theory is proposed and applied to the decision making for Construction Scheme. Firstly, the multi-layer assessment objects are analyzed with this method and property values of evaluation indexes are quantified. Then, the ultimate catastrophe function is obtained through different catastrophe models. In order to calculate, integrate and obtain the total value of Catastrophe, the decision making can be carried out. The outcome from concrete application of construction scheme optimization indicates that it is reasonable and has avoided the problem of calculating coefficient of weight subjectively with clear thread and simple calculation.

An investigation of the magne-totransport properties of Ir-Mn/Co-Fe-B/Al-O/Co-Fe-B magnetic tunnel junctions (MTJs) after annealing. The magnetic properties and microstructure analyses were done using a vibrating sample magnetometer (VSM), x-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM).

The density functional theory (DFT) is used for calculating the nickel nanowires that are embedded in a carbon nanotube and its applicability for studying the electronic transport along nanowires is assessed. The results have helped in understanding the correlation between the transport properties of nanowires and their microstructures.

High quality ZnO thin films are grown by plasma-enhanced molecular-beam epitaxy on sapphire substrates and free-exciton absorption and exciton-LO phonon absorption peaks is observed in the films at room temperature. It is indicated that the exciton states are stable even at room temperature.

The electroluminescent properties of three different structures (A:ITO/SiO2/Alq3/SiO2/Al, B:ITO/Alq3/SiO2/Al and C:ITO/SiO2/Alq3/Al based on the tris-(8-hydroxyquinoline) aluminum thin films are investigated. Results showed a blue electroluminescence at 457 nm was obtained from device (A) and (B) and the green emission at 518 nm was obtained from device (C).

Purpose - The purpose of this paper is to investigate a new approach for making a bio-based adhesive from a new resource, rice bran (RB) adhesive. Design/methodology/approach - RB solution was prepared and its pHs were adjusted to either 8.5-9.0 or 10.0-10.5. The solid content of slurry was controlled at ˜18 per cent and then gelatinised in a water bath shaker at 60°C for 2?h or at 100°C for 1?h. The bonding strength of RB adhesive was determined by testing the strength of three-layer plywood. A differential scanning calorimeter (DSC) was used for detecting the reaction energy and curing temperature. According to the DSC analysis, hot pressing at three temperatures was performed to select the best bonding conditions. Then, a two level split-plot design was used to determine the effects of gelatinisation and pH on the bonding strength of RB adhesive. Thus, the formulation of RB adhesive was optimised. In order to improve the water resistance of RB adhesive, toluene diisocyanate (TDI) was used as a cross linking agent. Findings - In the study reported here, a RB adhesive was developed by alkaline modification. Very high pH was not necessary, when RB adhesive with pH 10.0-10.5 was gelatinised at 100°C for 1?h, its bonding strength was significantly lower than pH 8.5-9.0 gelatinised at 60°C for 2?h. Water resistance of RB adhesive improved significantly when TDI was added as a cross linking agent. Compared to pure RB adhesive, the RB-TDI mixed adhesive started curing at a higher temperature. For RB adhesive curing, 130°C was a suitable hot pressing temperature. Research limitations/implications - Though the RB adhesive developed had a good bonding strength, its water resistance and dark colour was not satisfactory, which risks discolour of light colour wood. Further study is needed to solve this problem. Practical implications - The approach provided a bio-adhesive with good bonding strength, reasonable working life, and without formaldehyde emission. Based on further study, RB adhesive could be considered a promising alternate adhesive in many applications such as paper board bonding and plywood. Originality/value - It provided a potential way to utilise by-product of agriculture, RB as industrial raw material. This will do farmers a great favour. Meanwhile, the modified RB adhesive is promising to partly or completely replace urea formaldehyde resin that mainly used in wood industry, avoiding formaldehyde emission and reducing the dependence on petroleum products. [ABSTRACT FROM AUTHOR]

Purpose - To investigate a new approach for making soy-based adhesive having appropriate properties for potential application in wood industry. Design/methodology/approach - Three chemicals were used for modifying protein contained in soy flour. According to orthogonal experiment design, nine soy-based adhesives were prepared. Shearing strength of plywood bonded with these adhesives was measured to evaluate the bonding strength of nine formulas. Based on statistic analysis, the main effect factor and an optimised formula were determined. Further investigation on the modification effect to protein molecule was conducted by Fourier Transform Infrared Spectroscopy. In order to facilitate practical application, the viscosity of optimum formula adhesive was measured to determine possible working life. Three additives were added to optimise formula for reducing mould growth. Findings - Based on soy-flour mass, the best combination of lime milk, sodium hydroxide (NaOH) and sodium silicate was 10, 2, and 20 per cent, respectively. NaOH was considered the main effect factor on bonding strength, and sodium silicate was of the second importance. The viscosity of the optimised adhesive changed lightly in 2?h, and significantly increased from 2 to 4?h. However, it still could spread on veneer, which indicated a reasonable working life for practical application. Based on soy flour mass, when 0.5 per cent sodium benzoate or 25 per cent phenol formaldehyde was added, mould growth could be restrained after early stage. Research limitations/implications - Though the studied soy-based adhesive had a good bonding strength and comparative water resistance, its pH was a little too high, which may cause risks of discolour of light coloured wood. Further study is needed to solve this problem. Practical implications - The approach provided a bio-adhesive with good bonding strength, comparative water resistance, reasonable working life, and without formaldehyde emission. Soy-based adhesive is considered a promising alternate adhesive in wood industry and other applications because of the above mentioned advantages. Originality/value - It provided a potential way to utilise by-product of agriculture, soy-flour, as industrial raw material. This will benefit farmers significantly. Meanwhile, the modified soy-based adhesive is promising to partly or completely replace urea formaldehyde resin that are mainly used in wood industry, avoiding formaldehyde emission and reducing the dependence on petroleum products. [ABSTRACT FROM AUTHOR]

The generation of runaway electrons during disruptions poses a serious threat for the operation of ITER. The efficiency of the injection of large amounts of impurities by massive gas injection or shattered pellet injection to achieve runaway suppression might be compromised due to low gas mixture efficiency and the high Rosenbluth density for runaway suppression. The transport of runaway electrons is dominated by magnetic perturbations. The magnetic perturbations have the advantage of expelling the runaway seeds before they reach high energy. Robust runaway suppression has been reached on J-TEXT with mode locking by the application of m/n  =  2/1 resonant magnetic perturbations before the thermal quench. The mode locking implemented large magnetic islands inside the plasma which acted as an explosive bomb during disruptions and led to stronger stochasticity in the whole plasma cross section. The NIMROD simulation indicates that this strong stochasticity expels the runaway seeds and results in runaway free disruptions on J-TEXT. This might provide an alternative runaway suppression technique during disruptions for large-scale tokamaks. [ABSTRACT FROM AUTHOR]

Increasing the plasma density is one of the key methods in achieving an efficient fusion reaction. High-density operation is one of the hot topics in tokamak plasmas. Density limit disruptions remain an important issue for safe operation. An effective density limit disruption prediction and avoidance system is the key to avoid density limit disruptions for long pulse steady state operations. An artificial neural network has been developed for the prediction of density limit disruptions on the J-TEXT tokamak. The neural network has been improved from a simple multi-layer design to a hybrid two-stage structure. The first stage is a custom network which uses time series diagnostics as inputs to predict plasma density, and the second stage is a three-layer feedforward neural network to predict the probability of density limit disruptions. It is found that hybrid neural network structure, combined with radiation profile information as an input can significantly improve the prediction performance, especially the average warning time (). In particular, the is eight times better than that in previous work (Wang et al 2016 Plasma Phys. Control. Fusion58 055014) (from 5 ms to 40 ms). The success rate for density limit disruptive shots is above 90%, while, the false alarm rate for other shots is below 10%. Based on the density limit disruption prediction system and the real-time density feedback control system, the on-line density limit disruption avoidance system has been implemented on the J-TEXT tokamak. [ABSTRACT FROM AUTHOR]

The temporal-spatial structures of plasma flows and turbulence around tearing mode islands are presented. The experiments were performed using Langmuir probe arrays in the edge plasmas of J-TEXT tokamak. The correlation analyses clearly show that the flows have similar structures of m/n  =  3/1 as the magnetic island does (m and n are the poloidal and toroidal mode numbers, respectively). The sign of the potential fluctuations for the flows inverses and the powers significantly reduce at q  =  3 surface. Approaching to the last closed flux surface for the magnetic islands, the radially elongated flow structure forms. The flows are concentrated near separatrix and show quadrupole structures. The turbulence is concentrated near X-point and partly trapped inside the magnetic islands. [ABSTRACT FROM AUTHOR]

The progress of experimental research over the last two years on the J-TEXT tokamak is reviewed and reported in this paper, including: investigations of resonant magnetic perturbations (RMPs) on the J-TEXT operation region show that moderate amplitude of applied RMPs either increases the density limit from less than 0.7nG to 0.85nG (nG is the Greenwald density, ) or lowers edge safety factor qa from 2.15 to nearly 2.0; observations of influence of RMPs with a large m/n  =  3/1 dominant component (where m and n are the toroidal and poloidal mode numbers respectively) on electron density indicate electron density first increases (decreases) inside (around/outside) of the 3/1 rational surface, and it is increased globally later together with enhanced edge recycling; investigations of the effect of RMPs on the behavior of runaway electrons/current show that application of RMPs with m/n  =  2/1 dominant component during disruptions can reduce runaway production. Furthermore, its application before the disruption can reduce both the amplitude and the length of runaway current; experimental results in the high-density disruption plasmas confirm that local current shrinkage during a multifaceted asymmetric radiation from the edge can directly terminate the discharge; measurements by a multi-channel Doppler reflectometer show that the quasi-coherent modes in the electron diamagnetic direction occur in the J-TEXT ohmic confinement regime in a large plasma region (r/a ~ 0.3–0.8) with frequency of 30–140 kHz. [ABSTRACT FROM AUTHOR]

Runaway currents following disruptions have an important effect on the first wall in current tokamaks and will be more severe in next generation tokamaks. The behavior of runaway currents in massive gas injection (MGI) induced disruptions have been investigated in the J-TEXT tokamak. The cold front induced by the gas jet penetrates helically along field lines, preferentially toward the high field side and stops at a location near the q  =  2 surface before the disruption. When the cold front reaches the q  =  2 surface it initiates magnetohydrodynamic activities and results in disruption. It is found that the MGI of He or Ne results in runaway free shutdown in a large range of gas injections. Mixture injection of He and Ar (90% He and 10%Ar) consistently results in runaway free shutdown. A moderate amount of Ar injection could produce significant runaway current. The maximum runaway energy in the runaway plateau is estimated using a simplified model which neglects the drag forces and other energy loss mechanisms. The maximum runaway energy increases with decreasing runaway current. Imaging of the runaway beam using a soft x-ray array during the runaway current plateau indicates that the runaway beam is located in the center of the plasma. Resonant magnetic perturbation (RMP) is applied to reduce the runaway current successfully during the disruption phase in a small scale tokamak, J-TEXT. When the runaway current builds up, the application of RMP cannot decouple the runaway beam due to the lower sensitivity of the energetic runaway electrons to the magnetic perturbation. [ABSTRACT FROM AUTHOR]

The acceleration of the co-current toroidal rotations around resonant surfaces by resonant magnetic perturbations (RMPs) through turbulence is presented. These experiments were performed using a Langmuir probe array in the edge plasmas of the J-TEXT tokamak. This study aims at understanding the RMP effects on edge toroidal rotations and exploring its control method. With RMPs, the flat electron temperature Te profile, due to magnetic islands, appears around resonant surfaces (Zhao et al 2015 Nucl. Fusion55 073022). When the resonant surface is closer to the last closed flux surface, the flat Te profile vanishes with RMPs. In both cases, the toroidal rotations significantly increase in the direction of the plasma current around the resonant surfaces with RMPs. The characteristics of turbulence are significantly affected by RMPs around the resonant surfaces. The turbulence intensity profile changes and the poloidal wave vector kθ increases with RMPs. The power fraction of the turbulence components in the ion diamagnetic drift direction increases with RMPs. The measurements of turbulent Reynolds stresses are consistent with the toroidal flows that can be driven by turbulence. The estimations of the energy transfer between the turbulence and toroidal flows suggest that turbulence energy transfers into toroidal flows. The result has the implication of the intrinsic rotation being driven by RMPs via turbulence. [ABSTRACT FROM AUTHOR]

The experimental research over last two years on the J-TEXT tokamak is summarized and presented in the paper. The high-performance polarimeter-interferometer developed on J-TEXT, aiming to measure electron density and Faraday angle simultaneously, has time response up to 1 µs, phase resolution <0.1° and spatial resolution ∼3 cm. Such high resolution permits investigations of fast equilibrium dynamics as well as magnetic and density perturbations associated with magnetohydrodynamic instabilities. Particle transport due to the sawtooth crashes is analysed. The sawteeth only partially flatten the core density profile and recovery between crashes implies an inward pinch velocity extending to the centre. The resonant magnetic perturbation (RMP) system on J-TEXT can generate a rotating helical field perturbation with a maximum rotation frequency up to 6 kHz, and dominant resonant modes of m/n = 2/1, 3/1 or 1/1. It is found that tearing modes can be easily locked and then rotate together with a rotating RMP. The effects of RMPs on plasma flows and fluctuations are studied with Langmuir probe arrays at the plasma edge. The toroidal velocity increases and the radial electric field decreases with RMP coil current when the RMP current is no more than 5 kA. When the RMP current reaches 6 kA, the toroidal velocity profile becomes flattened near the last closed flux surface. The geodesic acoustic mode is damped in most of the edge region, while the low frequency zonal flow is damped inside the islands, but increases at its boundary. [ABSTRACT FROM AUTHOR]

The first comprehensive measurements of plasma flows and fluctuations nearby static magnetic islands driven by resonant magnetic perturbations are presented. These experiments were performed using multiple Langmuir probe arrays on the edge plasmas of the J-TEXT tokamak. Controlled variations of the island size and location are explored. This study aims to understand the interaction between turbulence and magnetic islands, and to elucidate magnetic island effects on edge turbulence and flow intensity profiles, edge electric fields, and thus confinement regime transitions. Turbulence and low frequency flows (LFFs) all drop inside the magnetic island, but increase at its boundary, as island width increases. The geodesic acoustic mode is damped in most of the edge area with magnetic islands. The sign of the radial electric field changes from negative to positive within the islands. The gradient of turbulent stresses vanishes at the island center, and becomes steeper at the boundaries of the islands. The particle transport induced by the turbulence is reduced inside the magnetic islands. The magnetic island effects on flows and turbulence can lead to an increase in LFFs and enhance Reynolds stresses near the last closed flux surface (LCFS). A stronger radial electric field layer can be formed near the LCFS when magnetic islands are present. The results suggest that magnetic islands can be used as a tool to enhance edge turbulence and flows, edge electric fields, and thus to trigger confinement regime transitions. [ABSTRACT FROM AUTHOR]