Properties of large-scale TIDs observed in central China

This paper investigates the large scale travelling ionospheric disturbances (LSTIDs) using the observation data of an HF Doppler array located in Central China. The data observed in a high solar activity year (year 1989) are analyzed to obtain the main propagation parameters of LSTIDs such as period, horizontal phase velocity and propagating direction. Results are outlined as follows: Most of the LSTIDs propagate southward; others tend to propagate northward, mostly in summer; dispersion of most LSTIDs is matched with that of Lamb pseudomode, while others have the dispersion of long period gravity wave mode. The horizontal phase velocities of these two modes are about 220 and 450 m/s respectively. The analysis shows that LSTIDs are strongly pertinent to solar activity and space magnetic storms; thus the results presented here are significant for the research of ionospheric weather in mid-low latitude region.

     

Low latitude ionospheric effects near longitude 120°E during the great geomagnetic storm of July 2000

A great geomagnetic storm occurred on July 15/16, 2000 with a minimum value of about -300 nT in Dst index. Collecting digisonde data from ionospheric stations at Chungli, Wuhan, Kokubunji and Anyang, the ionospheric responses at the low latitudes near longitude 120(E during this storm are analyzed in this paper. There was a strong negative phase storm at low latitudes on July 16. The G-condition in the ionograms was clearly seen on the early first day after the commencement of geomagnetic storm. Those were considered to be caused by the storm-induced increase in the concentration ratios of neutral molecular O2 or N2 to atom O. On July 17 and some days thereafter, a positive phase storm appeared. In addition, anomalous equatorial ionization anomaly (EIA) inhibitions and developments were observed on July 16 and 17. There were also prominent nighttime enhancements in foF2 during these days, and the diurnal variation of foF2 was less clear than before.     

一类带扰动的随机脉冲泛函微分方程解的渐近性北大核心CSCD

该文讨论了一类带扰动的随机脉冲泛函微分方程解的渐近性.通过比较扰动方程的解和原方程的解,得到了两者逼近的充分条件.首先,两者在有限的时间区间上相互逼近;其次,当扰动趋于零时,区间长度趋于无穷大,在这个区间上两个解仍然是相互逼近的.最后,举例说明了结果的有效性.     

乘子交换子的有界性

本文研究了乘子与Lipschitz函数生成的交换子,建立了这类交换子在Lebesgue空间与Hardy空间中的有界性．     

Marcinkiewicz积分在Herz型Hardy空间上的性质

给出了Marcinkiewicz积分在Herz型Hardy空间上的有界性证明。即当n(1 - 1q) ≤α 相似文献   

Sobolev空间上多尺度分析的性质

对Sobolev空间上多尺度分析的性质进行了探讨,给出了稠密性条件的一个特征刻划。     

Properties of the Central Points in Linear Programming Problems

In this paper we list several useful properties of central points in linear programming problems. We study the logarithmic barrier function, the analytic center and the central path, relating the proximity measures and scaled Euclidean distances defined for the primal and primal–dual problems. We study the Newton centering steps, and show how large the short steps used in path following algorithms can actually be, and what variation can be ensured for the barrier function in each iteration of such methods. We relate the primal and primal–dual Newton centering steps and propose a primal-only path following algorithm for linear programming.     

Some Topological Properties of Charming Spaces

In this paper, we mainly discuss the class of charming spaces. First, we show that there exists a charming space such that the Tychonoff product is not a charming space. Then we discuss some properties of charming spaces and give some characterizations of some class of charming spaces. Finally, we show that the Suslin number of an arbitrary charming rectifiable space is countable.     

On Some Properties of $c$-Frames

In this paper we discuss about $c$-frames, namely continuous frames. Since, $c$-frames are generalizations of discrete frames, we generalize some results of discrete frames to continuous version. We explain some results about relations of projections in Hilbert spaces and $c$-frames to characterize these frames. Also, we will specify (precisely) the synthesis and frame operators of Bochner integrable $c$-frames. Finally, we classify Hilbert-Schmidt operators by $c$-frames and express some new identities for Parseval $c$-frames.     

空间的几种超投影性质及其局部化

讨论Banach空间几种超投影性质(及其相应的局部化性质)之间的关系,证明了在Banach空间X自反的条件下,X是l_p-次投影空间的充要条件是X^*是l_p-超投影空间,X是局部l_p-次投影空间的充要条件是X^*是局部l_p-超投影空间,以及X是局部次投影空间的充要条件是X^*是局部超投影的。其中1/p+1/q=1(p>1,q>1)。     

向量值Musielak-Orlicz空间的两种几何性质(英)

设Ｘ是复Ｂａｎｃｈ空间,Ｍ（ｔ,ｕ）是以ｔ为参数的满足某些通常条件的Φ－函数．我们证明了;（ｉ）Ｍｕｓｉｅｌａｋ－Ｏｒｌｉｃｚ空间Ｌ_Ｍ（Ｘ）具有解析ＵＭＤ性质当且仅当Ｘ具有;（ｉｉ） Ｌ_Ｍ（Ｘ）具有解析ＲＮ性质当且仅当Ｘ具有．     

Brownian Motion and Ornstein–Uhlenbeck Processes in Planar Shape Space

We discuss Brownian motion and Ornstein–Uhlenbeck processes specified directly in planar shape space. In particular, we obtain the drift and diffusion coefficients of Brownian motion in terms of Kendall shape variables and Goodall–Mardia polar shape variables. Stochastic differential equations are given and the stationary distributions are obtained. By adding in extra drift to a reference figure, Ornstein–Uhlenbeck processes can be studied, for example with stationary distribution given by the complex Watson distribution. The triangle case is studied in particular detail, and some simulations given. Connections with existing work are made, in particular with the diffusion of Euclidean shape. We explore statistical inference for the parameters in the model with an application to cell shape modelling.      

Geometric Properties of Jet Schemes

This article shows how properties of jet schemes relate to those of the singularity on the base scheme. We will see that the jet scheme's properties of being ?-factorial, ?-Gorenstein, canonical, terminal, and so on are inherited by the base scheme.     

一类振荡积分算子在Wiener 共合空间上的有界性

假设a,b0并且K_(a,b)(x)=(e~(i|x|~(-b)))/(|x|~(n+a))定义强奇异卷积算子T如下:Tf(x)=(K_(a,b)*f)(x),本文主要考虑了如上定义的算子T在Wiener共合空间W(FL~p,L~q)(R~n)上的有界性.另一方面,设α,β0并且γ(t)=|t|~k或γ(t)=sgn(t)|t|~k.利用振荡积分估计,本文还研究了算子T_(α,β)f(x,y)=p.v∫_(-1)~1f(x-t,y-γ(t))(e~(2πi|t|~(-β)))/(t|t|~α)dt及其推广形式∧_(α,β)f(x,y,z)=∫_(Q~2)f(x-t,y-s,z-t~ks~j)e~(-2πit)~(-β_1_s-β_2)t~(-α_1-1)s~(-α_2-1)dtds在Wiener共合空间W(FL~p,L~q)上的映射性质.本文的结论足以表明,Wiener共合空间是Lebesgue空间的一个很好的替代.     

Integrability Properties of the Maximal Operator on Partial Sums of Fourier Series in Orlicz Spaces

Let S* (f be the majorant function of the partial sums of the trigonometric Fourier series of f. In this paper we consider the Orlicz space Lπ and give a generalization of Soria's result [S1]. Let π (t) be a concave function with some nice properties and . If there exists a positive constant a₀ < 1 such that then we have .     

基于{2}-逆的广义逆的构造及其性质

从代数的角度出发,分别给出了基于{2}-逆的三种广义逆:{2,3}-逆,{2,4}-逆以及{2,3,4}-逆,得到了代数上的各种构造和一些几何特性,从而补充了对广义逆的研究.     

Banach空间中全纯映射的若干性质

本文将全纯映射的若干性质推广到Ｂａｎａｃｈ空间，并应用这些性质研究有界域中的凸映射与星形映射．     

Properties for a Class of Holomorphic Mapson Hilbert Space

Itiswell-knownthattheanalyticfunctionwithpositiverealpartintheunitdiscofthecomplexplaneplaysaveryimportantroleinthegeometrictheoryofcomplexvariablefunc-tions.Ithasbeenremarkablehowtoextendtheclassicalresultofthetheoryoffunctionstoabstractspacesinrecentyears[2].Inthisnotewedefineageneralizedhalf-planeinHilbertspaceandfindthebiholomorphicmapoftheunitballonHilbertspaceontothishalf-plane.Asacorollary,wegiveashortproofofaresultin[5].UsingtheaboveholomooorphicmapweobtainthedistortiontheoremandPick…     

弱P-调和映射流的紧性性质

分别考虑了映入球面及紧致的齐性Ｒｉｅｍａｎｎｉａｎ空间的弱Ｐ－调和映射流；通过球面及齐性Ｒｉｅｍａｎｎｉａｎ空间的对称性质，证明了弱Ｐ－调和映射流的紧性性质．