■_0-弱基及相关问题(英文)

证明在空间X中下列论述等价:(1)X有σ-离散的■0-弱基;(2)X有σ-局部有限的■0-弱基;(3)X是■0-弱第一可数的空间,■0-弱基是开、闭遗传的,点可数■0-弱基是cs*-网.并讨论■0-弱基,sn-网,cs-网以及cs*-网的关系.     

关于■_0-sn-度量空间(英文)

先给出■0-sn-网的定义,并用实例说明此定义比■0-弱基更弱,并再讨论■0-sn-网的一些性质,得出■0-弱基、■0-sn-网、cs-网、cs*-网之间的一些等价关系.     

锌对小麦萌发和早期生长发育的影响

报道了用不同浓度锌溶液处理小麦种子对其萌发、叶绿素含量、细胞膜透性及生物量的影响.结果表明:低浓度锌促进小麦萌发、叶绿素合成以及生物量的积累;但随着锌浓度升高,种子萌发率显著降低、叶绿素合成受阻、生物量降低,细胞膜透性亦增大.     

(￡)0-sn-网的注记

利用序列商映射建立了具有可数(R)0-sn-网的空间与可分度量空间之间的联系,讨论了可分度量空间的可数到一、序列商映像.证明了在序列空间中,下列叙述等价:(1)X有σ-离散的(N)0-sn-网；(2)X有σ-局部有限的(N) 0-sn-网；(3)X有σ-遗传闭包保持的(N)0-sn-网；(4)X是(N)0-sn-弱第一可数的(N)-空间；(5)X有由闭子集构成的σ-紧有限的(N)0-sn-网.     

皮带机停机失灵事故的原因分析

本文分析了皮带机停机失灵的事故原因，事故状况，及处理办法。     

CULTURE OF WHEAT PROTOPLAST ——HIGH FREQUENCY MICROCOLONY FORMATION AND PLANT REGENERATION

Embryogenic calli were induced from the mature seeds of the hexaploid semi-winter wheat. The embryogenic cell line was established, and then the friable calli suitable for suspension were induced by adjusting the content of reduced N and changing the 2,4DAA concentration. Protoplasts were isolated from the suspension cells and cultured(?)in KM8P and some other media. A great number of microcolonies were obtained. By altering media, the microcolonies were promoted to grow further and form compact or nodule-like calli. Intact plants were regenerated through organogenesis and embryogenesis on differentiation media.     

Riemann流形上Laplace算子第一特征值的一点注记

本文研究了黎曼流形上Laplace算子的第一特征值,利用流形的测地球上的Sobolev常数进行讨论并进行Moser迭代,得到闭的黎曼流形上Laplace算子第一特征值的一个下界估计.     

A DIFFERENTIABLE SPHERE THEOREM WITH PINCHING INTEGRAL RICCI CURVATURE

In this article, we introduce the Hausdorff convergence to derive a differentiable sphere theorem which shows an interesting rigidity phenomenon on some kind of manifolds.     

浅谈数学专业英语教学

从数学专业英语教学中存在的问题入手,结合实际教学研究,提出一种称为"以点带面"的教学方法.实践表明,这种发散思维的教学方法提高了学生学习专业知识和英语的主动性和积极性,学习效果明显.     

Three-body force effect on the properties of nuclear matter under the gap and continuous choices within the BHF approach

We have calculated and compared the three-body force effects on the properties of nuclear matter under the gap and continuous choices for the self-consistent auxiliary potential within the Brueckner-Hartree-Fock approach by adopting the Argonne V₁₈ and the Bonn B two-body potentials plus a microscopic three-body force (TBF). The TBF provides a strong repulsive effect on the equation of state of nuclear matter at high densities for both the gap and continuous choices. The saturation point turns out to be much closer to the empirical value when the continuous choice is adopted. In addition, the dependence of the calculated symmetry energy upon the choice of the self-consistent auxiliary potential is discussed.