Cooling performance of hybrid refrigerant of solid nitrogen and small amount of neon for the purpose of HTS power applications

We have investigated cooling performance of a hybrid refrigerant of solid nitrogen and small amount of neon by using a short sample of Bi-2223/Ag tape as a cooling target. Solid nitrogen is expected as a heat capacitor for HTS applications operated below triple point temperature of nitrogen, and we have proposed in our previous study a method for overcoming the problem of its thermal contact with a cooling target with the aid of small amount of liquid neon. This paper discusses the phase state as well as the quantity of neon required for such an improvement. Nitrogen gas was introduced into a sample chamber through a mass flow controller, and then was liquefied and solidified by a Gifford–McMahon cryocooler. After that, in order to improve thermal contact of the solid nitrogen with the sample, neon gas was also introduced into the chamber at 25 K where neon can be liquefied. Cooling performance of such a hybrid refrigerant with different inputs of neon was evaluated by measuring temperature rise of the sample with the transportation of overcurrent. As a result, neon could suppress the temperature rise even in gas state, and the existence of liquid neon could additionally suppress the temperature rise. Furthermore, the required proportion of the liquid neon to the solid nitrogen was very small. From these results, we concluded that introducing neon until neon can be liquefied was the best way to make the most of the potential of the hybrid refrigerant.     

On the effect of residual gas on ionization waves in inert gases

The paper deals with the influence of concentration of residual gases in spectroscopically pure neon on parameters of ionization waves in a low-pressure plasma. The change in the concentration of residual gases was produced by a purification of neon by molecular sieves. The measurements concerned the dispersion and frequency dependences of the amplitude together with the self-excitation limit of p-type ionization waves in neon.     

Return of neon to the gas phase from the glass walls of a bulb by thermal diffusion

Optical spectroscopy has been applied to the intensity variation in the 585.2-nm line of neon due to the return of neon from the glass walls of the bulb to the gas phase by thermal diffusion. An approximate calculation is made on the neon transport in the glass.     

Kinetic analysis of the factors limiting the output power of the Ne--CuBr UV laser

The parametric optimization of the Ne--CuBr UV laser excited by longitudinal pulsed discharge is analysed by using a self-consistent kinetic model. Consistent characteristics of the optimization process are obtained by comparing with the experimental results. Simulation results show that neon ions come into being along with considerable depletion of the ground-state copper atoms. And the optimization of the discharge tube diameter is the tradeoff between the specific output photon density and the total active volume. Both the optimal neon gas pressure and the optimal reservoir temperature result from the balance between the neon ion density and the ground-state copper atom density to arrive at a maximum of their product.     

Long-lived population of the metastable 2s state in muonic hydrogen

Preliminary experimental results of the search for long-lived metastable μp(2s) are presented. The μp(2s) are identified via muon transfer to neon in a gas mixture of hydrogen and several percent of neon at mbar pressures. An energy-dependent 1s transfer rate to neon has been observed. The time spectra can only be explained assuming a nonzero μp(2s) population. This revised version was published online in August 2006 with corrections to the Cover Date.     

硅铝酸银分子筛吸附氖原子的第一性原理计算

采用基于第一性原理的密度泛函理论(DFT)和局域密度近似(LDA)方法,优化计算硅铝酸银分子筛吸附Ne原子体系的几何结构,能量,电子能带和电荷密度分布。结果表明,硅铝酸银为层状的周期结构,具有直径为a=5.390 Å的孔道。在分子晶体孔道的轴线上,桥O原子附近(I)和表面Ag+离子附近(II)的能量均有利于对Ne原子的吸附。尽管Ne(I)的能量最低,但是SiO4四面体排斥产生的能垒在动力学上不利于Ne原子的吸附。电子能带和电荷分布显示,Ne(II)原子主要受库仑极化的影响,其电子能带的能量较高,Ne(I)原子与桥O原子之间的共价作用能够降低对应的电子能带能量。     

硅铝酸银分子筛吸附氖原子的第一性原理计算

采用基于第一性原理的密度泛函理论(DFT)和局域密度近似(LDA)方法,优化计算硅铝酸银分子筛吸附Ne原子体系的几何结构,能量,电子能带和电荷密度分布。结果表明,硅铝酸银为层状的周期结构,具有直径为a=5.390 Å的孔道。在分子晶体孔道的轴线上,桥O原子附近(I)和表面Ag+离子附近(II)的能量均有利于对Ne原子的吸附。尽管Ne(I)的能量最低,但是SiO4四面体排斥产生的能垒在动力学上不利于Ne原子的吸附。电子能带和电荷分布显示,Ne(II)原子主要受库仑极化的影响,其电子能带的能量较高,Ne(I)原子与桥O原子之间的共价作用能够降低对应的电子能带能量。     

Saturated dispersion resonance observed in the width of a He-Ne laser beam with an intracavity neon cell

A narrow dispersion-like resonance is found in the width of the beam of a He-Ne laser with an intracavity neon cell. The width of the beam was determined by measuring the difference between the power in its axial circular zone and in an adjacent coaxial zone of annular shape. The zones were selected by spatial division of the beam power in half by a mirror with a circular aperture. The resonance obtained is spectrally locked to the center of the neon absorption line and is interpreted as a result of action of the nonlinear lens of the refractive index in the neon. By comparing the experimental data with the numerical model of Gaussian beam formation, the nonlinear lens component of the refractive index of neon is estimated.     

Theoretical investigation of structures,compositions, and phase transitions of neon hydrates based on ices Ih and II

Thermodynamic conditions of existence in the p-T plane and the composition of neon hydrates based on ices Ih and II are determined. The occupancy of neon in cages (channels) of ices Ih and II at temperatures below 0°C is calculated. It is shown that the occupancy of neon in hydrate based on ices cages decreases with growing temperature. Lines of monovariant equilibria between gas phase (neon)-neon hydrate based on ice Ih-liquid water (or ice II) and neon-gas phase (neon)-hydrate based on ice II-liquidwater (or ice II) are found. The line of divariant equilibria between neon hydrate based on ice Ih-neon hydrate based on ice II has been also calculated. The possibility of ice stabilization due to inclusion of neon into ice cages (channels) is shown.     

Total cross-sections for the scattering of positrons by helium,neon, and argon at intermediate energies

A slow positron beam time of flight system in which scattering is localised to a region of the flight path close to the slow positron source is described. Total cross-sections measured in helium, neon, and argon at intermediate energies are presented. The results for helium and neon are in agreement with the recent results of Brenton et al. While significant disagreement still exists in the argon data. The helium and neon data are in agreement with the sum rule predictions of Bransden et al.     

Townsend coefficient and efficiency of the formation of runaway electrons in neon

Basic ionization and drift properties are simulated for neon by the method of multiparticle dynamics. This calculation revealed that, in neon—in just the same way as in other gases that were studied previously—the Townsend ionization regime is realized even in strong fields if the distance between electrodes is rather large. The dependences of basic ionization and drift properties on the reduced electric-field strength are obtained. The results agree with available experimental data. The escape curve separating the region of efficient electron multiplication from the region in which electrons leave the discharge gap without undergoing multiplication is found for neon. The efficiency of the formation of a runaway-electron beam in helium and neon is simulated.     

Na-Ne混合气体扩散系数的计算

用面积分方法计算钠原子与氖原子间的相互作用势,根据计算扩散系数的Chapman-Enskog理论,文中计算了Na-Ne混合气体在温度200～700K范围内的扩散系数.计算结果与已有的实验结果符合得相当好.     

Characteristic study on an ESD suppressor by the FDTD method

The FDTD method was used to study the characteristics of an ESD suppressor filled with air, neon, argon, and helium. Obtained capacitance of the ESD suppressor filled with air was validated by measurement data and TDMM simulations. No large differences are found among the obtained capacitances for the ESD suppressor filled with air, neon, argon, and helium. But the ESD suppressor filled with air has a much higher trigger and clamping voltage than the ESD suppressor filled with neon, argon, or helium. The calculated capacitances are presented for different conditions. The ESD currents, charges, and electric fields are also presented.     

非全裸氟离子与氖原子碰撞中的转移电离研究

采用位置灵敏探测和散射离子 反冲离子飞行时间技术测量了强相互作用区F2 + 和F3 + 离子与Ne原子碰撞中的转移电离截面与单电子俘获截面之比 .与Fq+ He实验结果进行了比较 ,并进行了定性讨论. The ratios of the cross-section of the transfer ionization to the single electron capture of Neon induced by F 2+ and F 3+ ions are measured by means of the time-of-flight technologie. In the present energy range, the transfer ionization C1I1 of neon can be considered as a two-step process, in which one electron is captured by projectile and another one is directly ionized, and the transfer ionization C1I2 process should be considered as a subsequent rearrangement of neon following...     

Novel neon-hydrate of cubic ice structure

The stability of ice I cubic (ice I_c) whose voids are occupied by neon particles is investigated using a hybrid type of isobaric grand-canonical Monte Carlo simulation. We show that the resulting neon hydrate is stable under high pressure and temperature where ice I_c alone is unstable, suggesting the existence of a novel neon hydrate of ice I_c. We also show through chemical potential calculation that the neon hydrate of the ice I_c structure is more favorable than the neon hydrate of the ice II structure, whose existence was proven from experiment under high pressure condition.     

Measurement of enhancement in field ionization of helium and neon by self field adsorption

A direct measurement of field ionization enhancement by self field adsorption has been carried out for helium and neon gases. The result shows a large enhancement factor for both helium and neon, in disagreement with present theories of field ionization with field adsorption.     

Role of neon in a decaying high-purity helium plasma

The evolution of the electron and atomic and molecular metastable densities and the radiation of the decaying plasma of helium with a 10^–5-fraction of neon additive is experimentally studied. A model of elementary processes in He–Ne plasma is constructed, which describes the formation and destruction of HeNe⁺ and Ne₂ ⁺ molecular ions and their contribution to the formation of the afterglow spectrum by the electronion recombination. The various criteria influence of neon on the parameters of the decaying plasma are studied. The possibility of determining the amount of neon in helium by measuring the relative intensities of helium molecular bands and neon spectral lines in the afterglow is considered.     

Dependence of the amplifying parameters on buffer gases in copper-vapor lasers

We use a pair of copper-vapor lasers in the oscillator–amplifier configuration for investigating the small-signal gain and the intensity saturation as the amplifying parameters, versus the pressure of various types of buffer gases. We show that the small-signal gain increases and the intensity saturation decreases with increase in the air pressure. Moreover, the values of these parameters are different for various gases used in the amplifier media. We show that both parameters are greater at the atmosphere of neon as a buffer gas than that of a mixture of helium and neon or air.     

High resolution threshold photoelectron spectra of neon and argon in the valence satellite region

Using a newly designed zerovolt-electron spectrometer, high resolution threshold photoelectron spectra of neon above the 2s and of argon above the 3s photoelectron thresholds were taken following excitation with synchrotron radiation. From these spectra we were able to derive quantitatively the multiplet splitting of two neon satellites and almost all argon photoelectron satellites up to 38eV. Strong deviations from statistical behavior of most multiplet components were found. This unusual behavior is explained by autoionization of double-excited neutral states into the continuum of the satellite states just above threshold.     

Dissociative Recombination of $${\text{Ne}}_{{\text{2}}}^{ + }$$ Molecular Ions with Electrons: Population of Ne(2р54р) Atoms in a Decaying Plasma

Optics and Spectroscopy - Decaying neon plasma has been investigated by kinetic spectroscopy. The experimental conditions were neon pressure of 0.2–152 Torr and electron density in the...