Pure Ne Research Articles

New emission band of solid nitrogen

New results on the study of radiation effects in solid nitrogen and N2-doped Ne matrix are presented, with a focus on the so-called γ-line origin. The irradiation was carried out in dc regime with an electron beam of subthreshold energy. The relaxation dynamics was monitored by emission spectroscopy: cathodoluminescence (CL) and nonstationary luminescence (NsL), along with current activation spectroscopy. Thermally stimulated luminescence (TSL) and exoelectron emission (TSEE) of pure nitrogen and N2 in the Ne matrix were measured in a correlated manner. Three emission bands were recorded in the NIR CL spectra of solid N2: 794, 802, and 810 nm. The band at 810 nm was detected for the first time. These three bands are characterized by similar behavior and form molecular series with spacing between adjacent vibrational energy levels of the ground state of 125 and 123 cm−1. These data cast doubt on the recently made assumption that the γ-line is attributed to the emission of the nitrogen anion N− [R. E. Boltnev, I. B. Bykhalo, I. N. Krushinskaya et al. Phys. Chem. Chem. Phys. 18, 16013 (2016)]. The processes of electron attachment and neutralization of positively charged species are discussed. It has been established that the γ-line in the TSL spectra of pure nitrogen and N2-doped Ne matrix correlates with TSEE currents and recombination emission of O+, N2+, and N4+ ions, which indicates its connection with the neutralization reaction. The measurement of NsL supported this conclusion. A new possible assignment of the γ-line and its satellites to the emission of tetranitrogen N4 is discussed.

Numerical Study of Plasma Behavior and Power Generation Characteristics in a Disk MHD Generator With Xenon-Seeded Neon Gas

Plasma behavior and power generation characteristics in a disk-shaped magnetohydrodynamic (MHD) power generator with xenon (Xe)-seeded neon (Ne) working gas have been examined by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$r$</tex-math> </inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta $</tex-math> </inline-formula> 2-D numerical simulation under the assumptions of isentropic gas flow and a non-MHD interaction. The seed fraction (mole% of Xe in the mixture) is varied from 0.0% (pure Ne) to 100.0% (pure Xe) to assess the effect that Xe seeding has on plasma behavior and power generation characteristics. Adding a small amount of Xe to Ne improves the power performance due to the resulting enhancement of electrical conductivity, whereas adding an excessive amount (over 5.0%) deteriorates the performance. At an appropriate load resistance, uniform plasma structure occurs for low seed fractions. However, the plasma structure becomes nonuniform for excessively high seed fractions (over 5.0%). This result suggests that adding an excessive amount of Xe can reduce the uniformity of the plasma structure in the generator. On the other hand, at low load resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&lt;$</tex-math> </inline-formula> the appropriate load resistance) and high load resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&gt;$</tex-math> </inline-formula> the appropriate load resistance), a nonuniform plasma structure occurs for any seed fraction and results in the deterioration of generator performance. The electron temperature ranges for maintaining uniform plasma structure become narrower as the seed fraction increases which can be attributed to the low ionization potential of Xe and its large atomic weight.

Development of a fully analytical equation of state using ab initio interaction potentials. Application to pure simple fluids: Noble gases Ne, Ar, Kr, and Xe

In this work, we have extended the first-order mean spherical approximation (FMSA) equation of state (EOS) of Tang and Lu [J. Chem. Phys., 99, 9828 (1993)] in order to predict accurately fluid phase diagrams using ab initio potentials. At this level of development, we restricted to simple spherical compounds.The original equation based on hard-core two-Yukawa (HC2Y) was improved by the following:•Adding a new approximate simple correction to include higher orders in the development of Tang and Lu to get an analytical model closer to the full MSA.•Including a term to a better account for the long-range behavior of two-body potentials.•Adding a three-body interaction term (1st order perturbation) based on Axilrod-Teller potential.A general recommendation for setting the hard-sphere diameter value was also given.The predictive capability of the EOS was tested in a systematic manner. First, we checked that various simple theoretical potential (Mie n-6 and Exp n-6) phase diagrams are well reproduced. Second, the EOS was used for predicting fluid phase diagrams of the pure noble gases fluid series Ne, Ar, Kr, and Xe using realistic (i.e. derived from ab initio) two-body and three-body interaction potentials. The model is in good agreement with the experimental phase diagrams.As a conclusion, the simple statistical-mechanics-based fully analytical EOS developed in this work predicts accurately fluid phase diagrams of simple spherical compounds using ab initio potentials. No adjustable parameter was used. This EOS constitutes a strong basis for future development of a predictive model based on ab initio potentials and applicable to more complex compounds.

Microscopic collective dynamics in liquid neon-deuterium mixtures: Inelastic neutron scattering and quantum simulations.

In this paper a combined neutron scattering and quantum simulation study of the collective dynamics in liquid Ne-D_{2} mixtures, at a temperature of T=30K and in the wave-vector transfer range 4 nm^{-1}<q<51nm^{-1}, is presented. Two D_{2} concentrations are investigated, one close to 25% molar and the other close to 50% molar, together with pure Ne. The dynamic structure factor for the centers of mass of the two molecular species is extracted from the neutron scattering data and subsequently compared with that obtained from three different quantum simulation methods, such as ring polymer molecular dynamics and two slightly different versions of the Feynman-Kleinert approach. A general agreement is found, even though some discrepancies both among simulations, and between simulations and experimental data, can be observed. In order to clarify the physical meaning of the present spectroscopic results, an analysis of the longitudinal current spectral maxima is carried out showing the peculiarities of the D_{2} center-of-mass dynamics in these mixtures. A comparison with the centroid molecular dynamics results obtained for the D_{2} center-of-mass self-dynamics in the same liquid mixtures is finally proposed.

Measurement of pressure shift and broadening coefficients for Ne 3s[3/2]2→3p[5/2]3 transition in Ne and He using diode-laser absorption spectroscopy

Measurements of pressure broadening and shift coefficients for 640.2 nm Ne line were performed in an RF discharge without stabilization of neutral gas temperature. A diode laser with a short external cavity was used for metastable neon absorption spectroscopy in a natural mixture of neon isotopes. An appropriate fit function was constructed permitting deduction of Doppler and Lorentz components for the Voigt profile of the spectral line. To determine pressure broadening ξ and shift β coefficients for pure Ne and Ne:He mixture we used the information about Lorentz linewidth, position of the line center and gas temperature derived from spectral line shape fitted to a model line profile. The values of the collisional coefficients reduced to 300 K in units of 10-10 s-1 cm3, are ξNe-Ne = (1.9±0.2), ξNe-He = (3.4±0.2); βNe-Ne = -(0.7±0.1), βNe-He = (0.13±0.04).

TOKES simulations of mitigated disruption thermal quenches in ITER

• TOKES numerical simulations of mitigated disruption thermal quenches, caused by SPI in ITER have been performed. • Bremsstrahlung and recombination radiation contributes significantly to the core cooling upon injection of mixed pellet • The minimum Ne amount in two mixed pellets, which radiates >90 % of the core plasma energy has been found. TOKES simulations of mixed Ne/D 2 pellet injection through 1 equatorial launcher into an ITER discharge of 280 MJ thermal plasma energy was carried out. Two kinds of pellets were simulated: ‘large’, containing 1.1∙10 24 D 2 molecules and ‘small’ with 2.6∙10 23 D 2 molecules, both with various amount of Ne and correspondingly lower quantities of D to preserve the pellet size. It was found that the physics of the core energy radiation by the mixed pellet is different from that of the pure Ne pellet. In case of the mixed pellet injection, bremsstrahlung and recombination radiation make a significant contribution to the core cooling along with the Ne line radiation, the latter being the only mechanism for pure Ne pellet injection. The minimum Ne amount in the mixed pellet, which radiates more than 90 % of the core plasma energy (the threshold) has been found to be 1∙10 20 Ne atoms for the large pellet and 2∙10 21 atoms for the small one.

Shattered pellet penetration in low and high energy plasmas on DIII-D

Shattered pellet injection (SPI) has been adopted as the baseline disruption mitigation system for ITER, as the radiative payload penetration into DIII-D plasmas from SPI is superior to those using the massive gas injection (MGI) method. Because of the substantial differences in the energy content of ITER plasma and those in present experiments, reliable 3D MHD modeling, benchmarked against present experiments is needed to project to ITER plasmas. In support of these needs, the depth of SPI fragment penetration in DIII-D plasmas was investigated by injecting SPI into two discharges with vastly different energy content and pedestal height. 400 Torr-L pure Ne fragmented pellets at a velocity of about 200 m s−1 were injected into a 0.2 MJ L-mode discharge and a 2 MJ super H-mode discharge. Results show deep penetration of SPI fragments into low-energy plasmas in DIII-D. SPI fragment penetration is reduced as the plasma energy content increases, with some discharges exhibiting penetration that is confined to the outer regions of the plasma. The injected SPI fragments are also spread out over a distance of about 20 cm, which results in some fragments arriving near the end of or after the thermal quench is over.

Impact of impurity mixture gas seeded by supersonic molecular beam injection on edge-localized modes in the HL-2A tokamak

Impurity seeding experiments in ELMy H-mode plasmas by using supersonic molecular beam injection (SMBI) have been performed in the HL-2A tokamak. Besides pure impurity gas (neon, argon), impurities mixed with the main ion fuelling gas by different ratios were seeded into the plasma. It has been observed that the ELM behavior and plasma confinement are very sensitive to the impurity ratio. For 30% Ne impurity seeding, large ELMs are replaced by high frequency bursts (HFBs), which have higher frequency and smaller amplitude compared to the ELMs and the peak heat load on the divertor plate was considerably reduced. Analyses indicate that HFBs originate from the pedestal region and enhance the pedestal particle transport, resulting in a softened pedestal gradient after SMBI. However, for the pure Ne and Ar SMBI seeding, the ELM frequency is decreased and the plasma confinement is moderately improved. Experimental observations suggest that the impurity mixture gas plays a role in changing the pedestal dynamics and there should be an optimal impurity ratio for efficient heat load control in ELMy H-mode plasmas.

Overview of the J-TEXT progress on RMP and disruption physics

The J-TEXT tokamak has been operated for ten years since its first plasma obtained at the end of 2007. The diagnostics development and main modulation systems, i.e. resonant magnetic perturbation (RMP) systems and massive gas injection (MGI) systems, will be introduced in this paper. Supported by these efforts, J-TEXT has contributed to research on several topics, especially on RMP physics and disruption mitigation. Both experimental and theoretical research show that RMP could lock, suppress or excite the tearing modes, depending on the RMP amplitude, frequency difference between RMP and rational surface rotation, and initial stabilities. The plasma rotation, particle transport and operation region are influenced by the RMP. Utilizing the MGI valves, disruptions have been mitigated with pure He, pure Ne, and a mixture of He and Ar (9:1). A significant runaway current plateau could be generated with moderate amounts of Ar injection. The RMP has been shown to suppress the generation of runaway current during disruptions.

Solidification and Acceleration of Large Cryogenic Pellets Relevant for Plasma Disruption Mitigation

The technology for producing, accelerating, and shattering large pellets (before injection into plasmas) for disruption mitigation has been under development at the Oak Ridge National Laboratory for several years, including a system on DIII-D that has been used to provide some significant experimental results. The original proof-of-principle testing was carried out using a pipe gun injector cooled by a cryogenic refrigerator (temperatures $\sim 8$ –20 K) and equipped with a stainless steel tube to produce 16.5-mm pellets composed of either pure D2, pure Ne, or a dual layer with a thin outer shell of D2 and core of Ne. Recently, significant progress has been made in the laboratory using that same pipe gun and a new injector that is an ITER test apparatus cooled with liquid helium. The new injector operates at $\sim 5$ –8 K, which is similar to temperatures expected with cooling provided by the flow of supercritical helium on ITER. An alternative technique for producing/solidifying large pellets directly from a premixed gas has now been successfully tested in the laboratory. Also, two additional pellet sizes have been tested recently (nominal 24.4 and 34.0 mm diameters). With larger pellets, the number of injectors required for ITER disruption mitigation can be reduced, resulting in less cost and a smaller footprint for the hardware. An attractive option is longer pellets, and 24.4-mm pellets with a length/diameter ratio of $\sim 3$ have been successfully tested. Since pellet speed is the key parameter in determining the response time of a shattered pellet system to a plasma disruption event, recent tests have concentrated on documenting the speeds with different hardware configurations and operating parameters; speeds of $\sim 100$ –800 m/s have been recorded. The data and results from laboratory testing are presented and discussed, and a simple model for the pellet solidification process is described.

Non-nearest neighbour ICD in clusters

Interatomic Coulombic decay (ICD) is an electronic decay process of excited, ionized systems. It has been shown to occur in a multitude of small and large systems. The effects of more than one possible decay partner are discussed in detail illustrated by simulated ICD electron spectra of NeAr clusters and pure Ne clusters. Hereby, the mostly underestimated contribution of decay with non-nearest neighbours is highlighted. In the neon clusters, the lifetime of the bulk atoms is found to be in excellent agreement with experiment (Jahnke et al 2004 Phys. Rev. Lett. 93 173401) while the lifetimes of the surface atoms differ significantly. Hence, the experimental lifetime can not purely be explained by the effect of the number of neighbours. We propose the possibility to investigate the transition from small clusters to the solid state by using the ICD electron spectra to distinguish between icosahedral and cuboctahedral cluster structures.

3D geometry and kinematic evolution of extensional fault-related folds, NW Red Sea, Egypt

Abstract Fault-related folds are common structural features found at a variety of scales in extensional settings, and have been recognized in both outcrop and subsurface studies. However, the detailed geometry and origin of complex 3D folds adjacent to normal faults are poorly known, and, in some cases, are interpreted to be due to strike-slip tectonics and post-rift contraction. Here we examine the 3D geometry of seismic-scale folds in a rift margin – the Red Sea – and discuss the interrelationship between the growth of normal faults and the development of their related folds. Detailed field mapping of the NW Red Sea rift system has shown that the rift margin is dominated by two large extensional fault systems formed by a series of linked NNW-, north–south- and NNE-striking fault segments. These linked segments exhibit distinct zigzag fault patterns and combine to form a number of NNW-trending faults that dip NE with dominant hanging-wall stratal dips to the SW. Hanging-wall stratal dips define 3D extensional fault-related synclinal folds in pre- and early synrift strata. The hanging-wall synclines are kilometre-scale, gently doubly plunging, with curved axial surface traces orientated sub-parallel to the bounding faults. Field data demonstrated that these folds are formed by along-strike variations in fault displacements, and they form transverse synclines combined with hanging-wall extensional fault-propagation folds. The complex 3D geometry of the hanging-wall synclines is the result of the along-strike segment linkage. Adjacent to the bounding faults, the stratal dips are sub-parallel to the faults as a result of extensional fault-propagation folding controlled by highly anisotropic pre-rift strata. Palaeo-strain analyses of fault-slip data, together with analysis of the fold geometry, clearly indicate that the faulting and folding in the NW Red Sea are formed by pure NE–SW extension during the Late Oligocene–Miocene rifting, and that contraction or strike-slip tectonics need not be invoked.

Statistical mechanics of the fashion game on random networks

A model of fashion on networks is studied. This model consists of two groups of agents that are located on a network and have opposite viewpoints towards being fashionable: behaving consistently with either the majority or the minority of adjacent agents. Checking whether the fashion game has a pure Nash equilibrium (pure NE) is a non-deterministic polynomial complete problem. Using replica-symmetric mean field theory, the largest proportion of satisfied agents and the region where at least one pure NE should exist are determined for several types of random networks. Furthermore, a quantitive analysis of the asynchronous best response dynamics yields the phase diagram of existence and detectability of pure NE in the fashion game on some random networks.

High harmonic generation in Ne and H_2 gas mixtures

High harmonic generation (HHG) enables the production of coherent light in the extreme-ultraviolet (XUV) spectral region. However, the radiation conversion efficiency from infrared to the XUV is low. We observed enhancement of HHG in gas mixtures of H2 and Ne compared to pure gases H2 or Ne. Our experiments show that at an intensity of ∼1.5×1014 W/cm2 and in mixtures of gases with significantly different ionization potentials (IPs), the initial HHG takes place in the component with lower IP (H2), inducing excited states and facilitating ionization and HHG in the component with higher IP (Ne). We show that the combination of the two gas components results in an enhancement or suppression of the output of high harmonics as compared to pure gases, which is also confirmed by the employed phenomenological model.

휨을 받는 하이브리드 강섬유 보강 초고성능 콘크리트 보의 구조 거동

ABSTRACT This paper concerns the flexural behavior of hybrid steel fiber-reinforced ultra high performance concrete (UHPC) beams. It presents experimental research results of hybrid steel fiber-reinforced UHPC with steel fiber content of 1.5% by volume and steel reinforcement ratio of less than 0.02. This study aims at providing realistic information about UHPC beams in bending in order to establish a reasonable prediction model for flexural resistance in structural code in the future. The experimental res ults show that hybrid steel fiber-reinforced UHPC is in favor of cracking resistance and ductility of beams. The ductility indices range through 9.2 to 15.2, which means high ductility of UHPC. Also, the flexur al capacity of beam which contains stirrups in pure bending zo ne is similar to that of beam which does not contain stirrups in pure bending zone. This result represents that the flexural capacity is not affected by the presence of stirrups whose spacing is 150 mm in bending zone.

Opportunistic Spectrum Access Using Partially Overlapping Channels: Graphical Game and Uncoupled Learning

This article investigates the problem of distributed channel selection in opportunistic spectrum access (OSA) networks with partially overlapping channels (POC) using a game-theoretic learning algorithm. Compared with traditional non-overlapping channels (NOC), POC can increase the full-range spectrum utilization, mitigate interference and improve the network throughput. However, most existing POC approaches are centralized, which are not suitable for distributed OSA networks. We formulate the POC selection problem as an interference mitigation game. We prove that the game has at least one pure strategy NE point and the best pure strategy NE point minimizes the aggregate interference in the network. We characterize the achievable performance of the game by presenting an upper bound for aggregate interference of all NE points. In addition, we propose a simultaneous uncoupled learning algorithm with heterogeneous exploration rates to achieve the pure strategy NE points of the game. Simulation results show that the heterogeneous exploration rates lead to faster convergence speed and the throughput improvement gain of the proposed POC approach over traditional NOC approach is significant. Also, the proposed uncoupled learning algorithm achieves satisfactory performance when compared with existing coupled and uncoupled algorithms.

Theoretical and experimental study of the influence of nitrogen admixture on characteristics of dc diffuse glow discharge in rare gases at intermediate pressures

An effect of nitrogen admixture on the electric field in positive column of diffuse glow discharge in various rare gases at intermediate pressures is studied both experimentally and theoretically. The discharge is maintained in a cylindrical glass tube. Earlier it was observed and reproduced in calculations that addition of N2 (1%) to Ar at pressure 40 Torr led to noticeable decrease in the electric field strength at a fixed discharge current. In the present work there are results for pure Ne and Ne + 1%N2 gas mixtures at pressure 40 Torr. It is found that the addition of N2 to Ne leads to the increase in the electric field strength; the observed effect is reproduced in calculations. The explanation of differences in the impact of N2 addition on the electric field strength in Ar and Ne discharges is given. On the basis of the performed analysis it is predicted that the addition of N2 to He leads to the increase in the electric field in the discharge and the addition of N2 to Xe leads to the decrease in the electric field. For the case of He, the prediction is experimentally confirmed in this work, while for the case of Xe, it is corroborated by literature data.

High grade neuroendocrine lung tumors: Pathological characteristics, surgical management and prognostic implications

Among non-small cell lung cancers (NSCLC), large cell carcinoma (LCC) is credited of significant adverse prognosis. Its neuroendocrine subtype has even a poorer diagnosis, with long-term survival similar to small cell lung cancer (SCLC). Our purpose was to review the surgical characteristics of those tumors. The clinical records of patients who underwent surgery for lung cancer in two French centers from 1980 to 2009 were retrospectively reviewed. We more particularly focused on patients with LCC or with high grade neuroendocrine lung tumors. High grade neuroendocrine tumors were classified as pure large cell neuroendocrine carcinoma (pure LCNEC), NSCLC combined with LCNEC (combined LCNEC), and SCLC combined with LCNEC (combined SCLC). There were 470 LCC and 155 high grade neuroendocrine lung tumors, with no difference concerning gender, mean age, smoking habits. There were significantly more exploratory thoracotomies in LCC, and more frequent postoperative complications in high grade neuroendocrine lung tumors. Pathologic TNM and 5-year survival rates were similar, with 5-year ranging from 34.3% to 37.6% for high grade neuroendocrine lung tumors and LCC, respectively. Induction and adjuvant therapy were not associated with an improved prognosis. The subgroups of LCNEC (pure NE, combined NE) and combined SCLC behaved similarly, except visceral pleura invasion, which proved more frequent in combined NE and less frequent in combined SCLC. Survival analysis showed a trend toward a lower 5-year survival in case of combined SCLC.Therefore, LCC, LCNEC and combined SCLC share the same poor prognosis, but surgical resection is associated with long-term survival in about one third of patients.

Comparison of Damages on Tungsten Surface Exposed to Noble Gas Plasmas

Tungsten was exposed to pure Ar or Ne plasmas over 1550 K at several incident ion energies. Even under the irradiation condition that the tungsten nanostructure is formed by He plasma irradiation, holes/bubbles and fiberform nanostructures were not formed on the surface by exposure to Ar or Ne plasmas. In addition, the results from energy dispersive X-ray spectroscopy supported the facts that Ar and Ne did not remain in the sample. We will discuss the reason for the differences in the damage to the tungsten surface exposed to noble gas plasmas.

Synchronous solid neuroendocrine breast carcinoma and abdominal lymphoma: A case report and review of the literature

Neuroendocrine tumors (NETs) are frequently associated with second primary malignancies (SPMs). Earlier studies have demonstrated that NETs are highly associated with synchronous or metachronous gastrointestinal and genitourinary SPMs. We report, for the first time, a case of pure NE breast carcinoma (NEBC) exhibiting all of the World Health Organization (WHO)-categorized morphological and phenotypic NE features (i.e., round solid nests of spindle cells, plasmacytoid cells, large clear or mucinous signet-ring cells with a peripheral palisading tendency and immunohistochemical positivity for the NE markers synaptophysin and chromogranin in more than 50% of the tumor cell population) along with synchronous abdominal non-Hodgkin’s lymphoma. In the present study, we review the diagnosis, clinicopathological features and histogenetic profiling of NEBC and discuss the literature relevant to the clinical and anatomopathological management of this case. This previously unreported case of synchronous solid NEBC and abdominal lymphoma, together with earlier studies showing that primary symptoms are caused by SPMs in a significant subgroup of NET patients, strongly supports the notion that NETs should be cautiously considered to be index tumors. Therefore, risk-adapted clinicopathological follow-up with systematic investigation is strongly recommended.