A rigid subspace of the real line whose square is a homogeneous subspace of the plane

Working in ZFC, we give an example as indicated in the title.

     

关于实Hilbert环

通过引进“强实Hilbert环”这一概念,本文证明了,一个环A是强实Hilbert环,当且仅当多项式环A[X]是实Hilbert环,当且仅当A[X]的每个实极大理想在A上的局限是实极大的,从而文献[1]中两个主要结果被否定.此外,本文还研究了所谓的“严格的实Hilbert环”,这类环对于半代数零点定理等方面的探讨更具应用意义.     

激光除锈过程的实时监测技术研究

对激光除锈过程中的实时监测技术进行了实验研究,结果表明:除锈过程中产生的声波强度会随着表面清洁度的变化而发生明显的变化,声波信号包含了除锈过程中的大量信息,可作为激光除锈实时监测的基本信号.     

红外单站被动定位技术速度更新算法研究

针对红外单站被动定位技术中空中机动目标的运动速度不断变化这一实际情况,提出了一种基于红外相机运动特性的对目标的运动速度进行实时更新的校正算法.该算法克服了大多基于匀速直线运动这一空间模型的红外单站被动定位方案目标速度不变的缺点,客观地反映了空中机动目标的实际运动状况,不仅能对目标的运动速度进行实时准确的更新校正,而且可推演出一种新的红外单站被动定位算法,对推动红外单站被动定位技术的工程实用化进程具有重要的意义.     

An implicit characteristic-flux-averaging method for the euler equations for real gases

A formulation of an implicit characteristic-flux-averaging method for the unsteady Euler equations with real gas effects is presented. Incorporation of a real gas into a general equation of state is achieved by considering the pressure as a function of density and specific internal energy. The Ricmann solver as well as the flux-split algorithm are modified by introducing the pressure derivatives with respect to density and internal energy. Expressions for calculating the values of the flow variables for a real gas at the cell faces are derived. The Jacobian matrices and the eigenvectors are defined for a general equation of state. The solution of the system of equations is obtained by using a mesh-sequencing method for acceleration of the convergence. Finally, a test case for a simple form of equation of state displays the differences from the corresponding solution for an ideal gas.     

Growth of Lévy trees

We construct random locally compact real trees called Lévy trees that are the genealogical trees associated with continuous-state branching processes. More precisely, we define a growing family of discrete Galton–Watson trees with i.i.d. exponential branch lengths that is consistent under Bernoulli percolation on leaves; we define the Lévy tree as the limit of this growing family with respect to the Gromov–Hausdorff topology on metric spaces. This elementary approach notably includes supercritical trees and does not make use of the height process introduced by Le Gall and Le Jan to code the genealogy of (sub)critical continuous-state branching processes. We construct the mass measure of Lévy trees and we give a decomposition along the ancestral subtree of a Poisson sampling directed by the mass measure. T. Duquesne is supported by NSF Grants DMS-0203066 and DMS-0405779. M. Winkel is supported by Aon and the Institute of Actuaries, EPSRC Grant GR/T26368/01, le département de mathématique de l’Université d’Orsay and NSF Grant DMS-0405779.     

Overpartitions and real quadratic fields

It is shown that counting certain differences of overpartition functions is equivalent to counting elements of a given norm in appropriate real quadratic fields.     

对NO生理作用的新认识及其电化学实时检测

本文综述了近年来学术界对ＮＯ生理作用的新认识，并介绍了现场实时检测生物活体中释放的ＮＯ浓度的电化学方法．     

Density computations for real quadratic units

In order to study the density of the set of positive integers for which the negative Pell equation is solvable in integers, we compute the norm of the fundamental unit in certain well-chosen families of real quadratic orders. A fast algorithm that computes 2-class groups rather than units is used. It is random polynomial-time in as the factorization of is a natural part of the input for the values of we encounter. The data obtained provide convincing numerical evidence for the density heuristics for the negative Pell equation proposed by the second author. In particular, an irrational proportion of the real quadratic fields without discriminantal prime divisors congruent to 3 mod 4 should have a fundamental unit of norm .

     

On the applicability of the “abt” concept

Kaiser's “abt” concept rests on the experimental establishment of a linear relation between band width at half height, b_0.5, and capacity ratio, k, according to His column specification quantity, h_real, is dependent on the square of the slope a, obtained from a linear regression analysis based on this relation. It is shown in the present paper that an improvement of the experimental conditions leading to a lower extra-column contribution to band broadening, b, introduces a tendency towards a negative curvature in the plot at low k values. The mean slope increases, and an uncritical linear regression would yield an h_real-value which is higher than before and which would be in the opposite direction to the requirements of a reliable column specification. Generally the linear regression analysis has to be moved to higher k regions in cases of curvature, especially as it is also shown that h_real is an estimation of the traditional HETP value, H∞, that would be obtained when k approaches infinity. This theoretically expected relation is a strong motivation for the use of h_real as a column specification, since the b_0.5-value associated with H∞ is expected to be practically independent of b.