Multiple M‐Effect Signal in Noble Gases and Hydrogen Mixture Discharge

The M‐effect (monochromatization‐effect) is a powerful process which can give high intensity monochromatic spectra with a certain wavelength depending on the type of used gas mixtures to generate the plasma state. The effect consists in the emission of a single spectral line emerging from plasma under specific experimental conditions involving one electropositive gas and one electronegative gas mixture. For example, in the case of Ne‐H₂ mixture, a clear monochrome radiation was obtained, corresponding to the λ_Ne =585.3 nm wavelength at 2p₁‐1s₂ transition in the Paschen notation, the pressures ranging between 10‐100 torr. In this paper we prove the general character of this effect, i.e. if the optical emission spectra (OES) reduced to selective lines can be noticed also in other multiple gas mixture discharges. The Ne‐Ar‐Xe mixture discharges with different percentages of H2 as electronegative gas added in has been investigated. The triple M‐effect, means three specific monochromatic lines, could be revealed in the OES at 50% of H2 addition in Ne‐Ar‐Xe mixture (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Purely electronic transport and localization in the Bose glass

We discuss transport and localization properties on the insulating side of the disorder dominated superconductor‐insulator transition, described in terms of the dirty boson model. Analyzing the spectral properties of the interacting bosons in the absence of phonons, we argue that the Bose glass phase admits three distinct regimes. For strongest disorder the boson system is a fully localized, perfect insulator at any temperature. At smaller disorder, only the low temperature phase exhibits perfect insulation while delocalization takes place above a finite temperature. We argue that a third phase must intervene between these perfect insulators and the superconductor. This conducting Bose glass phase is characterized by a mobility edge in the many body spectrum, located at finite energy above the ground state. In this insulating regime purely electronically activated transport occurs, with a conductivity following an Arrhenius law at asymptotically low temperatures, while a tendency to superactivation is predicted at higher T. These predictions are in good agreement with recent transport experiments in highly disordered films of superconducting materials.     

平面刚体系统的参数预调节保辛算法

保辛积分方法在约束哈密顿系统中有着重要的应用,是因为其在长时间仿真中表现出极好的稳定性。然而随着仿真时长增加,保辛格式通常具有较大的相位误差累积。本文提出了一种平面多刚体系统的参数预调节保辛积分方法。通过推导具有待定参数的改进的拉格朗日方程,并将其与已有保辛格式相结合并预先调节相关参数取值,可以大幅降低数值解的相位误差。理论分析与数值结果表明参数预调节保辛积分方法不仅保持了辛结构,而且具有很低的相位误差累积。因此,参数预调节保辛积分方法可应用于长时间仿真分析。     

“同心协力”策略研究

针对"同心协力"拓展项目中队员的协同控制问题,建立了在理想条件下的最优策略模型,以及在非精确控制条件下的鼓面倾斜模型,讨论了稳定性要求对最优策略的影响,给出当球跳动方向偏离竖直方向后,鼓的控制方法及效果.最后对2019年"高教社杯"全国大学生数学建模竞赛B题的参赛论文予以简要评述.     

Validity of extracellular water assessment with saliva samples using plasma as the reference biological fluid

Extracellular water (ECW) assessment is based on dilution techniques, commonly using blood sampling. However, plasma collection is an invasive procedure. We aimed to validate the use of saliva for ECW estimation by the bromide dilution technique using plasma as the reference method, in a sample of elite athletes. A total of 89 elite athletes with a mean age of 20.4 ± 4.4 years were evaluated. Baseline samples were collected before sodium bromide oral dose administration, and enriched samples were collected 3 h post‐dose administration. The bromide concentration was assessed by high‐performance liquid chromatography. Comparison of means, concordance coefficient correlation (CCC), multiple regression and Bland–Altman analysis were performed. The ECW from saliva explained 91% of the variance in ECW by plasma with a standard error of estimation of 0.91 kg. The CCC between alternative and reference methods was 0.952. No significant trend was observed between the mean and difference of the methods, with limits of agreement ranging between ?1.5 and 2.1 kg. These findings reveal that bromide dilution volume calculated from saliva samples is a valid noninvasive method for ECW assessment in elite athletes. Copyright © 2012 John Wiley & Sons, Ltd.     

关于L_p-相交体的Busemann-Petty型问题(英文)

Haberl and Ludwig introduced the L_p-intersection body I_pK for an originsymmetric star body K in R~n,where p < 1 and p ≠ 0.In this paper,we consider the Busemann-Petty’s problem for L_p-intersection bodies I_pK and I_pL.That is,whether I_pK ■ IpL implies Vol_n(K) ≤ Vol_n(L).We obtain that for two origin-symmetric star bodies K and L in R~n,such that(R~n,||·||K) embeds in L_p and I_pK ■ IpL,then vol_n(K) ≤ vol_n(L) for 0 < p < 1 and vol_n(K) ≥ vol_n(L) for p < 0.     

随机弦长矩与弦幂积分

本文研究了凸体的五种类型的随机弦长分布.利用限弦投影原理和运动测度积分的方法,揭示了凸体的弦幂积分与随机弦长的矩之间的本质联系.     

基于信息技术测量篮球的空气阻力系数

为了测出篮球在一般投篮过程的空气阻力系数,使用摄像机拍摄篮球竖直下落的全过程,并用软件将视频分解为帧图像,得到篮球下落的坐标和时间实验数据.用Matlab比较理论图线和实验所得的图,最终确定空气阻力系数近似值k=0.5±0.03.     

p-平行体类及其p-Steiner点的连续性

结合平行体及L_p-Firey组合的定义,引入了凸体的p-平行体.首先,研究了p-平行体与p-平均宽度之间的关系,然后,证明了p-平行体类在新的度量下的几个性质,并得到了关于p-平行体类的p-Steiner点的连续性结果.     

On the variance of random polytopes

A random polytope is the convex hull of uniformly distributed random points in a convex body K. A general lower bound on the variance of the volume and f-vector of random polytopes is proved. Also an upper bound in the case when K is a polytope is given. For polytopes, as for smooth convex bodies, the upper and lower bounds are of the same order of magnitude. The results imply a law of large numbers for the volume and f-vector of random polytopes when K is a polytope.