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High precision current measurement is very important for the calibration of various high-precision equipment and the measurement of other precision detection fields. A new current sensor based on diamond NV color center magnetic measurement method is proposed to realize the accurate measurement of current. This new current method can greatly improve the accuracy of current measurement. Experiments show that the linearity of the current sensor based on diamond NV color center can reach up to 33 ppm, which is superior to other current sensors and solves the problem of low linearity. When the range of input current is 5-40 A, the absolute error of calculated current is less than 51 µA, and the relative error is 2.42 × 10-6 at 40 A. Combined with the research content and results of the experiment, the application of the current sensor in the field of current precision measurement is prospected.

The generation of runaway electrons (REs) is observed during the low-density helium ohmic plasma discharge in the Experimental Advanced Superconducting Tokamak (EAST). The growth rate of hard x-ray (HXR) is inversely proportional to the line-average density. Besides, the RE generation in helium plasma is higher than deuterium plasma at the same density, which is obtained by comparing the growth rate of HXR with the same discharge conditions. The potential reason is the higher electron temperature of helium plasma in the same current and electron density plateau. Furthermore, two Alfvén eigenmodes driven by REs have been observed. The frequency evolution of the mode is not fully satisfied with the Alfvén scaling and when extension of the Alfvén frequency is towards 0, the high frequency branch is ~50 kHz. The different spatial position of the two modes and the evolution of the helium concentration could be used to understand deviation between theoretical and experimental observation.

Building exit as a bottleneck structure is the last and the most congested stage in building evacuation. It is well known that obstacles at the exit affect the evacuation process, but few researchers pay attention to the effect of stationary pedestrians (the elderly with slow speed, the injured, and the static evacuation guide) as obstacles at the exit on the evacuation process. This paper explores the influence of the presence of a stationary pedestrian as an obstacle at the exit on the evacuation from experiments and simulations. We use a software, Pathfinder, based on the agent-based model to study the effect of ratios of exit width (D) to distance (d) between the static pedestrian and the exit, the asymmetric structure by shifting the static pedestrian upward, and types of obstacles on evacuation. Results show that the evacuation time of scenes with a static pedestrian is longer than that of scenes with an obstacle due to the unexpected hindering effect of the static pedestrian. Different ratios of D/d have different effects on evacuation efficiency. Among the five D/d ratios in this paper, the evacuation efficiency is the largest when d is equal to 0.75D, and the existence of the static pedestrian has a positive impact on evacuation in this condition. The influence of the asymmetric structure of the static pedestrian on evacuation efficiency is affected by D/d. This study can provide a theoretical basis for crowd management and evacuation plan near the exit of complex buildings and facilities.

An N-stage three-waveguide system is proposed to improve the robustness and the fidelity of the resonant tunneling passage. The analytic solutions to the tunneling dynamics at the output are derived. When the number of subsystems increases, tunneling efficiency approaches to 100% in a large range and resonant tunneling is robust against variations in the phase mismatch and peak tunneling rate.

We demonstrate a new management of multi-stage optical parametric generator (OPG) and amplifier (OPA) to obtain high-energy picosecond sources with high beam quality. The setup of multi-stage OPG-OPA requires mode-matching between the pump beam and the stable mode of the OPG-OPA. In a proof-of-principle experiment, the single-pass multi-stage OPG-OPA consists of three walk-off compensated KTP crystal pairs and two lenses, pumped by an 86 ps, 1064 nm 10 kHz picosecond laser. The signal light at ∼ 1.77 μ m has an average output power of 502 mW with record energy up to 50.2 μ J. The beam quality factor of the signal light can be improved to M x 2 × M y 2 = 1.87 × 2.16 after filtering out about 40% signal power. To the best of our knowledge, it is the first picosecond single-pass multi-stage OPG-OPA pumped at kHz regime.

The core impurity confinement properties are experimentally investigated in the Experimental Advanced Superconducting Tokamak (EAST) plasma heated by lower hybrid wave (LHW) and electron cyclotron resonance heating (ECRH) (LHW+ECRH). It is shown that the impurity confinement time (τ imp) in the L-mode plasma jointly heated by LHW and ECRH is weakly dependent on electron density but strongly dependent on the heating power, thus it is shorter than that in LHW-only heated L-mode plasma with the similar plasma parameters. The combined heating of LHW and ECRH can reduce the collisionality and indicates a more effective heating method for core τ imp reduction and normalized poloidal beta (β P) improvement. It should be emphasized that in this high β P operation window the small ELM regime can be accessed, and an L-mode level τ imp (40 ms–80 ms) and high β N (∼ 1.7) can be obtained simultaneously. It means that this typical small ELMy H-mode regime has an advantage in avoiding the serious tungsten accumulation, and will be competitive in future long-pulse steady-state and high-performance operation with high-Z material plasma-facing components.

In 2015 campaign, deuterium atomic emission spectra (D α ) under the Zeeman effect in boundary region had been measured by a high resolution optical spectroscopic multichannel analysis (OSMA) system based on passive spectroscopy during the deuterium plasma discharge on EAST tokamak, and part of the works about the Zeeman effect on D α spectra had already been done. However, the asymmetric phenomena of D α emission spectra under the Zeeman effect were observed in process of analyzing the spectral data. To understand the asymmetric phenomena and acquire the useful local plasma information, an algorithm was proposed and used to analyze the asymmetry of the emission spectra under the Zeeman effect with all polarization components (π and ±σ). In the algorithm, the neutral atoms were considered to follow the Maxwell distribution on EAST, and I +σ ≠ I −σ was considered and set. Because of the line-averaged spectra along the viewing chord, the emission spectra were considered from two different regions: low-field side (LFS) and high-field side (HFS). Each spectral line was classified into three energy categories (the cold, warm, and hot) based on different atomic production processes in boundary recycling. The viewing angle θ (between the magnetic field B and the viewing chord), magnetic field B at two spectral emission positions (HFS and LFS) and the Doppler shift of all three energy categories of each spectral line were all considered in the algorithm. The effect of instrument function was also included here. The information of the boundary plasma were acquired, the reason for the asymmetric phenomena was discussed, and the boundary recycling during the discharge were studied in the paper. Based on fitting a statistical data of acquired fitting results, an important conclusion was acquired that the ratio of the spectral line intensity in HFS and LFS was proportional to the square of that of the corresponding magnetic field.

On the basis of a volume of fluid (VOF) liquid/liquid interface tracking method, we apply a two-dimensional model to investigate the dynamic behaviors of droplet breakup through a splitting microchannel. The feasibility and applicability of the theoretical model are experimentally validated. Four flow regimes are observed in the splitting microchannel, that is, breakup with permanent obstruction, breakup with temporary obstruction, breakup with tunnels, and non-breakup. The results indicate that the increase of the capillary number Ca provides considerable upstream pressure to accelerate the droplet deformation, which is favorable for the droplet breakup. The decrease of the droplet size contributes to its shape changing from the plug to the sphere, which results in weakening droplet deformation ability and generating the non-breakup flow regime.

Based on neon gas puffing, an active feedback control of H-mod plasma divertor detachment experiment was successfully operated on the EAST tokamak. During the feedback control discharge, the plasma was detached by puffing neon gas and the strike point splitting phenomenon on divertor target was also clearly observed by divertor probes diagnostic. In boundary region, many neutral particle processes (atom and molecule) were happened and accompanied by their emission spectra under the detachment discharge. By studying these emission spectra, it is helpful for us to understand the role of atoms and molecules in boundary recycling, which is important for studying the physical mechanism of divertor detachment. For the Fulcher-α system ( d ( 3 p ) 3 Π u ± → a ( 2 s ) 3 Σ g + ) , D2 emission spectra in the range from 601 nm to 606 nm were observed, identified and fitted in the detachment experiment for the first time on the EAST, and the spectra in the Q(0–0) band ( d 3 Π u − → a ( 2 s ) 3 Σ g + ) in the Q branch of the Fulcher-α system were used for detailed analysis to acquire the boundary region temperature T e (below 5 eV), which could not be provided very well by other diagnostics on the EAST. An electronic version deuterium molecular spectral line database was established to identify the spectral lines and a multi-peak fitting program was developed to fit and analyze the observed spectra.

During edge localized modes (ELMs), the sheath evolution in front of the Experimental Advanced Superconducting Tokamak (EAST) upper divertor is studied to estimate the sputtered tungsten (W) atoms from the divertor target. A large potential drop across the sheath is formed during ELMs by compared with inter-ELMs, and the maximum of sheath potential drop can exceed one thousand of eV in current EAST operation. Due to the enhancement of the sheath potential drop during ELMs, the W physical sputtering yield from the deuterium (D) ions and the impurity ions on the upper divertor target is found to be significant. It is established that the sputtered W yield during ELMs is at least higher by an order of magnitude than inter-ELMs, and D ions and carbon (C) ions are the main ions governing the W production for the current H-mode with ELMs discharges. With increase in the pedestal electron temperature, the maximum of the D and C ion impact energy during ELMs shows a nearly linear increase, and the D ions have sufficient impact energy to cause the strong W physical sputtering. As a consequence, the D ions may dominate the sputtered W flux from the divertor target when the C concentration is controlled less than one percent for the higher heating power H-mode with ELM discharges in near future.

In the present study, high-quality apatite-type La9.33Ge6O26 powders are successfully synthesized by a facile molten-salt synthesis method (MSSM) at low temperatures, using LiCl, LiCl/NaCl mixture (mass ratio 1:1) as molten salt, respectively. Experimental results indicate that the optimal mass ratio between reactant and molten salt is 1:2, and LiCl/NaCl mixed molten-salt is more beneficial for forming high-quality La9.33Ge6O26 powders than LiCl individual molten-salt. Comparing with the conventional solid-state reaction method (SSRM), the synthesis temperature of apatite-type La9.33Ge6O26 powders using the MSSM decreases more than 350 °C, which can effectively avoid Ge loss in the preparation process of precursor powders. Furthermore, the powders obtained by the MSSM are homogeneous, non-agglomerated and well crystallized, which are very favorable for gaining dense pellets in the premise of avoiding Ge loss. On the basis of high-quality precursor powders, the dense and pure ceramic pellets of La9.33Ge6O26 are gained at a low temperature of 1100 °C for 2 h, which exhibit higher conductivities (, and lower activation energies (, ) than that synthesized by the SSRM.

This paper finds the approximate analytical scattering state solutions of the arbitrary 1-wave Schrodinger equation for the generalized Hulthen potential by taking an improved new approximate scheme for the centrifugal term. The normalized analytical radial wave functions of the l-wave Schrodinger equation for the generalized Hulthen potential are presented and the corresponding calculation formula of phase shifts is derived. Some useful figures are plotted to show the improved accuracy of the obtained results and two special cases for the standard Hulthen potential and Woods–Saxon potential are also studied briefly.

To investigate the radiative divertor behavior and physics for the scenario of impurity seeded plasma in ITER, the radiative divertor experiments with argon (Ar) seeding under ITER-like tungsten divertor condition were carried out during recent EAST campaigns. The experimental results reveal the high efficiency of reducing heat load and particle flux onto the divertor targets owing to increased radiation by Ar seeding. We achieve detached plasmas in these experiments. The inner–outer divertor asymmetry reduces after Ar seeding. Impurities, such as Ar, C, Li, and W, exist in the entire space of the vacuum chamber during EAST operations, and play important roles in power exhausting and accelerating the plasma detachment process. It is remarkable that the contamination of the core plasma is observed using Ar seeding owing to the sputtering of plasma facing components (PFCs), particularly when Ar impurity is injected from the upper tungsten divertor.

A stable and insoluble V2O5nH2O/tetra-n-butyl titanate (TBO) hybrid xerogel was synthesized by the sol–gel method. This novel material proved to be an efficient absorbent with an absorption capacity of 179 mgg−1 for Rhodamine B (RhB) in water due to its unique layered structure, which can effectively accommodate RhB molecules between its layers as demonstrated by XRD and FTIR spectroscopic analyses.

The excellent physical and chemical properties of cubic boron nitride (c-BN) film make it a promising candidate for various industry applications. However, the c-BN film thickness restricts its practical applications in many cases. Thus, it is indispensable to develop an economic, simple and environment-friend way to synthesize high-quality thick, stable c-BN films. High-cubic-content BN films are prepared on silicon (100) substrates by radio frequency (RF) magnetron sputtering from an h-BN target at low substrate temperature. Adhesions of the c-BN films are greatly improved by adding hydrogen to the argon/nitrogen gas mixture, allowing the deposition of a film up to 5-μm thick. The compositions and the microstructure morphologies of the c-BN films grown at different substrate temperatures are systematically investigated with respect to the ratio of H2 gas content to total working gas. In addition, a primary mechanism for the deposition of thick c-BN film is proposed.

Growth and structural properties of thin a-C films prepared by the 60 MHz very-high-frequency (VHF) magnetron sputtering were investigated. The energy and flux of ions impinging the substrate were also analyzed. It is found that the thin a-C films prepared by the 60 MHz sputtering have a lower growth rate, a smooth surface, and more sp3 contents. These features are related to the higher ion energy and the lower ions flux onto the substrate. Therefore, the 60 MHz VHF sputtering is more suitable for the preparation of thin a-C film with more sp3 contents.

Molecular dynamics simulation is used to investigate the relationship between Voronoi entropy and viscosity for rapid solidification processing of Zr36Cu64 binary alloy melt. The simulation results at different temperatures, cooling rates, and pressures, show that Voronoi entropy is able to accurately describe the relationship of the transition between the cluster structure and the viscosity of Zr36Cu64 binary alloy melt through Voronoi polyhedron analysis. That is, the higher the degree of order of the microstructure, the lower the Voronoi entropy is and the higher the viscosity is. The simulation provides an important reference for studying metallic glass with high glass-forming ability.

Lanthanum silicates La10Si6?xMgxO27?x (x = 0?0.4) were prepared by solid state synthesis to investigate the effect of Mg doping on crystal structure and ionic conductivity. Rietveld analysis of the powder XRD patterns reveals that Mg substitution on Si site results in significant enlargement of channel triangles, favoring oxide-ion conduction. Furthermore, an increase of Mg concentration significantly influences the linear density of interstitial oxygen, which plays an important role in ionic conductivity. The Arrhenius plots of La10Si6?xMgxO27?x (x = 0?0.4) suggest that Mg-doped samples present higher conductivity and lower activation energy than non-doped La10Si6O27, and La10Si5.8Mg0.2O26.8 exhibits the highest conductivity with a value of 3.0?10?2 S ?cm?1 at 700 ?C. Such conductive behavior agrees well with the refined results. The corresponding mechanism has been discussed in this paper.

The structural and magnetic properties of SmFeO3 with B site substitution of non-magnetic atom Al are investigated. The x-ray diffraction patterns show that SmFe(1−x)AlxO3 remains an orthorhombic structure within the whole doping range, and the unit-cell volume decreases monotonically with the increase of doped Al concentration. Besides, the octahedral tilting distortions of FeO6 are found to be alleviated while the tolerance factor increases. However, the relationship between the lattice parameters and Al concentration is observed to deviate from Vegard's rule, and this may be caused by magnetostriction effects. For the doping content values in a range 0 ≤ x ≤ 0.6, the ferromagnetism, antiferromagnetism, and paramagnetism are observed to occur continuously. Moreover, the magnetization and the spin reorientation temperature (Tk) decrease monotonically as Al content value increases. With the doping content values being x = 0.8 and 1.0, these compounds only show paramagnetic behavior.

Raman spectra of amorphous carbon nitride films (a-C:N) resemble those of typical amorphous carbon (a-C), and no specific features in the spectra are shown due to N doping. The present work provides a correlation between the microstructure and vibrational properties of a-C:N films from first principles. The six periodic model structures of 64 atoms with various mass densities and nitrogen contents are generated by the liquid-quench method using Car?Parinello molecular dynamics. By using Raman coupling tensors calculated with the finite electric field method, Raman spectra are obtained. The calculated results show that the vibrations of C=N could directly contribute to the Raman spectrum. The similarity of the Raman line shapes of N-doped and N-free amorphous carbons is due to the overlapping of C=N and C=C vibration bands. In addition, the origin of characteristic Raman peaks is also given.

Point defect states in two-dimensional phononic crystal of a hollow mercury cylinder in a water host are studied. An improved plane expansion method combined with the supercell technique is used to calculate the band gaps and the pressure distribution at the defect position. The sonic pressure of defect modes shows that the waves are localized at or near the defect. As the filing fraction increases, more defect modes appear in the band gaps.