We report a tubular plasma source that is capable of creating high-activity nitrogen plasma flow at low pressure. The high-activity nitrogen plasma was produced by a continue low-frequency discharge, ...in which an intensive pulsed discharge was observed when the electrode was polarized by the positive voltage. Excited at 10 to 115W, the plasma source allows loading the power density as high as ~80W/cm3 to the plasma, producing high-activity nitrogen plasma with a maximum dissociation degree of nitrogen larger than 10%. Based on the tubular plasma source, a special system of plasma enhanced chemical vapor deposition has been developed for deposition of low H-content amorphous hydrogenated silicon nitride (a-SiNx:H) films at room temperature.
•A novel plasma source generating high-activity nitrogen flow at low pressure is reported.•The plasma source allows loading the power density as high as ~80W/cm3 to the plasma.•The plasma source is capable of producing high-activity nitrogen plasma with a dissociation degree larger than 10%.•A special PECVD system is designed for deposition of low H-content a-SiNx:H films at room temperature.
Status of the HIRFL–CSR complex Yuan, Y.J.; Yang, J.C.; Xia, J.W. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
12/2013, Letnik:
317
Journal Article
Recenzirano
•HIRFL is in a very positive state and can provide all ion species with maximum energy to 1GeV/u (A/q=2).•Present status of HIRFL complex is given as well as the new progress on operation and ...improvement.•With emphasize on HIRFL–CSR project, main features realized during the commissioning and operation are described in detail.•The progress on physics experiments and hadron cancer therapy are also presented.
The HIRFL–CSR, as an upgrade of the HIRFL, has been put into operation since 2008. Together with a series of improvements of injector cyclotrons, the HIRFL is in a very good state and can provide all ion species from proton to uranium with energy variable from ion source energy to 1GeV/u (A/q=2). Present status of the HIRFL–CSR complex is given. Main features realized during the commissioning and operation are described in detail. The progress on physics experiments and cancer therapy are also presented.
ABSTRACT
The effect of notch types and stress concentration factors (Kt) on low cycle fatigue life and cracking of the DZ125 directionally solidified superalloy has been experimentally investigated. ...Single‐edge notched specimens with V and U type geometries were tested at 850 °C with stress ratio R = 0.1. High temperature in situ optical method was used to observe crack initiation and short crack propagation. Scanning electron microscope observation of fracture was used to analyse the failure mechanism. The results reveal that fatigue resistance decreases with Kt increasing from 1.76 to 4.35. The ratcheting is found to be affected by both Kt and the nominal stress from the displacement–force curve. In situ observations indicate that the cracking does not occur at the notch apex but at the location where the max principal stress or Hill's stress is the highest. According to the scanning electron microscope observations, the failure of the notched specimens strongly depends on the anisotropy microstructures.
Highly constricted plasmas are an active research area because of their ability to generate high activity of plasma beams, which exhibit potential in applications of material processing and film ...deposition. In this study, optical emission spectroscopy was used to study the highly constricted nitrogen plasma created at low pressure. The vibrational and rotational temperatures of molecules were determined by fitting the second positive system of nitrogen molecule. Under the conditions of the power densities as high as 7 ∼ 85 W/cm3 and the pressures of 2 ∼ 200 Pa, the determined rotational temperature was found to be relatively low, increasing from 350 to 700 K and the vibrational temperature keeping at ∼ 5000 K. The analysis of dissipated power revealed that ∼ 80 % of input power is dissipated for the nitrogen molecule dissociation and the creation/loss of ions at the tube wall, producing an as high as 1012 ∼ 1013 cm−3 plasma with the nitrogen dissociation degrees of 2%∼15%. With the increase in the discharge pressure, more input power was found to be dissipated in the dissociation of nitrogen molecules instead of creation of ions, resulting in a higher density of radicals.
Amorphous hydrogenated silicon-nitride (a-SiNx:H) quantum-dot (QD) films were successfully deposited on Si substrates using a specially designed system of plasma enhanced chemical vapor deposition. ...The a-SiNx:H QD films exhibit strong visible photoluminescence (PL) with a tunable peak energy ranging from 3.26 to 2.52eV, depending on the deposition pressure. The PL process was studied in terms of temperature-dependent and time-resolved PL spectra in comparison with the theoretical predication of the band-tail luminescence, and then the tunable PL spectra were assigned to the recombination of excitons in the localized states at the band tails of the a-SiNx:H QDs.
We study the superconducting vortex states induced by the interplay of long-range Pearl repulsion and short-range intervortex attraction using Langevin dynamics simulations. We show that at low ...temperatures the vortices form an ordered Abrikosov lattice both in low and high fields. The vortices show distinctive modulated structures at intermediate fields depending on the effective intervortex attraction: ordered vortex chain and kagome-like vortex structures for weak attraction; bubble, stripe and antibubble lattices for strong attraction. Moreover, in the regime of the chain state, the vortices display structural transitions from chain to labyrinthine (or disordered chain) and/or to disordered states depending on the strength of the disorder.
Prism ZnO nanomaterials coated with Ca(OH)
2 were prepared by direct precipitation. TEM micrographs showed that dendritic Ca(OH)
2 seemed to attach on the surface of nanosized ZnO. The XRD patterns ...indicated that the coating was Ca(OH)
2·2Zn(OH)
2·2H
2O. The nanosized ZnO coated with Ca(OH)
2 as the anode materials were investigated by the charge–discharge cycle measurement and EIS. The combination of ZnO nanomaterials and Ca(OH)
2 prevented the discharge product ZnO from dissolving in the electrolyte. Therefore, the Ca(OH)
2-coated ZnO nanomaterials exhibited higher electrochemical activity than the pure nanosized ZnO, including high the discharge capacity and discharge middle voltage, low the charge middle charge voltage. Although Ca(OH)
2 resulted in more difficult activation, EIS showed that the charge-transfer resistance was lower than that of the pure ZnO nanomaterials.
Triple-negative breast cancer (TNBC) is the most aggressive breast cancer, and thus, has limited treatment options. Neuropilin1 (NRP1) is a multi-functional transmembrane protein that interacts with ...a number of signaling receptors and plays an important role in cancer progression. Previous studies demonstrated that the expression of NRP1 is activated and promotes the progression of breast cancer particularly in TNBC compared to other molecular subtypes; however, whether or not the level of NRP1 expression is related to the progression of TNBC warrants further study. In the current study, we determined the expression and function of NRP1 and evaluated the clinical significance of NRP1 in patients with TNBC. In addition, we determined whether or not an NRP1 antagonist potentiates the inhibitory effects of paclitaxel (PTX) in patients with TNBC. In our clinical study, NRP1 had higher expression in TNBC tissues than non-TNBC tissues at the same stage, and NRP1 was an independent prognostic factor. Specifically, the high expression of NRP1 was associated with shorter survival in TNBC patients. In addition, TNBC cells treated with NRP1 antagonist significantly potentiated the effect of PTX on cell proliferation, cell migration, and apoptosis. Our findings suggest that NRP1 expression can act as an independent prognostic factor for TNBC patients, and the combination of PTX and an NRP1 antagonist may be an effective treatment regimen for TNBC.
The creep-fatigue interaction in directionally solidified nickel-base superalloy was analyzed with the modified Chaboche-based unified viscoplasticity constitutive model. The model features the ...anisotropic material behavior, hardening/softening, and stress relaxation. Simple low-cyclic fatigue and specified hold time experiments were conducted on a directionally solidified superalloy (DZ125) at temperatures over 760°C. The material parameters were optimized considering its tensile, cyclic and creep behavior with the Levenberg–Marquardt optimization procedure. The model was constructed in FORTRAN and integrated in FEA software UMAT/ABAQUS. The results show that experimental and simulated hysteresis loop size/shape, peak stresses, stress relaxation, and related areas are closely matched. The modified constitutive model was found to be instrumental for revealing the fatigue and creep-fatigue interaction behavior of such materials and can be used for practical applications.
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