磁流体方程组弱解在负指标Besov空间中基于旋度和电流的正则性标准

本文研究了不可压磁流体方程组弱解的正则性准则,设(u(t,x),6(t,x))是不可压磁流体方程组在(O,T)上的光滑解,如果旋度和电流密度满足(▽× u,▽× b) ∈ L 2-a/2 (O, T;B-aa∞, ∞(R3)) ηL1-a/2(O,T;B-∞1,-a∞(R3)),0＜α＜1,则光滑解(u(t,x),b(t,x))可以连续延拓到(O,T'),T'＞T.而且这个条件可以保证满足能量不等式的弱解是(O,T)上的光滑解.     

Global Regularity of 2D Leray-Alpha Regularized Tropical Climate Models

In this paper, we establish the global regularity of 2D leray-alpha regularized tropical climate models. The global strong solution to the system with a half Laplacian of the first baroclinic model of velocity $(\Lambda v)$ and thermal diffusion $(-\Delta\theta)$ or with only the dissipation of the barotropic mode $(-\Delta u)$ are obtained.     

Pseudohexagonal 2D DNA crystals from double crossover cohesion

Two-dimensional pseudohexagonal trigonal arrays have been constructed by self-assembly from DNA. The motif used is a bulged-junction DNA triangle whose edges and extensions are DNA double crossover (DX) molecules, rather than conventional DNA double helices. Experiments were performed to establish whether the success of this system results from the added stiffness of DX molecules or the presence of two sticky ends at the terminus of each edge. Removal of one sticky end precludes lattice formation, suggesting that it is the double sticky end that is the primary factor enabling lattice formation.     

Orthorhombic Inverse Perovskitic Ba3TtO (Tt = Ge,Si) as Zintl Phases

The isotypic title compounds are obtained in high yield from the reactions of Ba, BaO, and Ge (Si) in welded Ta containers slowly cooled from 1100 °C. The structure of Ba₃GeO was determined by single-crystal X-ray diffraction (orthorhombic symmetry; Pnma (No. 62); a = 7.591(1), b = 10.728(1), c = 7.551(1) Å; Z = 4; R = 0.058, R_w = 0.065 for 780 reflections (I > 3σ(I)) with 2θ_max = 60°)). The structure consists of slightly deformed OBa₆ octahedra that are tilted by £ 14° with respect to their positions in the ideal inverse perovskite structure. These distortions optimize eight of the original twelve equal Ba–Ge distances. The ideal cubic Ca₃SiO (a = 4.699(1) Å) has also been synthesized.     

非线性晶体应用于中长波红外固体激光器的研究进展

中波红外3～5μm波段以及长波红外8～12 μm波段的激光处于大气传输窗口,在激光成像、环境监测、激光雷达、激光医疗、化学遥感和红外对抗等领域有着非常广阔的应用前景.基于非线性光学晶体,采用光学非线性频率变换技术在实现中长波红外固体激光输出方面具有明显的技术优势.该方法激光器结构简单,且晶体本身并不参与能量交换,因而没有量子亏损,从而产热很少.同时具有单色性好、宽调谐、高功率等优点.本文针对常用以及新型非线性光学晶体,对其应用于中长波红外固体激光器的研究进展做了详细的总结.     

浙江维管植物分布新记录

报道了浙江维管植物分布新记录10种,分别为：睫毛蕨科Pleurosoriopsidaceae的睫毛蕨Pleurosoriopsis makinoi （Maxim.ex Makino） Fomin;榆科Ulmaceae的山黄麻Trema tomentosa （Roxb.） Hara;樟科Lauraceae的华南木姜子Litsea greenmaniana Allen和黄枝润楠Machilus versicolora S.K.Lee & F.N.Wei;景天科Crassulaceae的东至景天Sedum dongzhiense D.Q.Wang & Y.L.Shi和高岭景天Sedum tricarpum Makino;紫金牛科Myrsinaceae的少年红Ardisia alyxiaefolia Tsiang ex C.Chen;禾本科Poaceae的广州鼠尾粟Sporobolus hancei Rendle、远东芨芨草Achnatherum extremiorientale （Hara） Keng ex P.C.Kuo和南荻Miscanthus lutarioriparius L.Liu ex Renvoize & S.L.Chen.其中,睫毛蕨科为浙江新记录科.凭证标本保存于浙江农林大学植物标本室（ZJFC）.     

沸石分子筛膜缺陷的形成及修复*

分子筛膜在化学传感器、膜分离和膜催化等领域有潜在的应用前景。缺陷的存在降低了分子筛膜的筛分作用和分离选择性,从而限制了其工业应用。本文综述了沸石分子筛膜缺陷形成及修复方面的研究进展,详细介绍了沸石分子筛膜缺陷形成的原因,并按照过程机理将分子筛膜修复方法划分为多次合成法、积炭结焦法、表面涂层法、化学气相沉积法以及液相化学沉积法等。在深入分析了各种修复方法优缺点的基础上,对今后分子筛膜修复技术的发展趋势进行了展望。     

Dendritic flower calcium hydroxide grown on aluminium substrate using polyacrylamide as a template

This paper reports one method to grow dendritic flower calcium hydroxide on aluminium substrate using polyacrylamide as a template. A series of electron microscopy images show new images of the products and together with themogravimetry differential thermal analysis and other conventional techniques, the composition of the products was found to be calcium hydroxide containing polyacrylamide. The result of the mechanism for the formation of the dendritic flower made of primary particles is also presented. An understanding of this mesoscale transformation process will be helpful in controlling the aggregation‐driven formation of complex higher‐order structures materials. This study could provide an additional tool for designing advanced materials and could be used for synthesis of more complex structures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)