不同沙粒底面下气泡脉动特性实验研究

通过高速摄影系统对电火花气泡与不同沙粒底面间的相互作用进行了实验研究,并改变气泡与沙粒底面之间的距离.实验结果表明:气泡在与沙粒底面的相互作用中会产生两种明显不同的现象,即形成与近刚性壁面类似的气泡射流以及“蘑菇状”气泡,“蘑菇状”气泡撕裂形成两个气泡,随后产生两个反方向的沿轴线方向的射流.沙粒底面边界具有刚性与弹性两种特征.另外,随着气泡与沙粒底面之间的距离d的增大,气泡脉动周期先增大然后减小,存在气泡脉动周期峰值.对于不同的沙粒底面边界,出现气泡脉动周期峰值的距离d随着沙底粒径的增大而越小.     

Lower and upper orientable strong radius and strong diameter of complete k-partite graphs

For two vertices u and v in a strong digraph D, the strong distance sd(u,v) between u and v is the minimum size (the number of arcs) of a strong sub-digraph of D containing u and v. For a vertex v of D, the strong eccentricity se(v) is the strong distance between v and a vertex farthest from v. The strong radius srad(D) (resp. strong diameter sdiam(D)) is the minimum (resp. maximum) strong eccentricity among the vertices of D. The lower (resp. upper) orientable strong radius srad(G) (resp. SRAD(G)) of a graph G is the minimum (resp. maximum) strong radius over all strong orientations of G. The lower (resp. upper) orientable strong diameter sdiam(G) (resp. SDIAM(G)) of a graph G is the minimum (resp. maximum) strong diameter over all strong orientations of G. In this paper, we determine the lower orientable strong radius and diameter of complete k-partite graphs, and give the upper orientable strong diameter and the bounds on the upper orientable strong radius of complete k-partite graphs. We also find an error about the lower orientable strong diameter of complete bipartite graph K_m,n given in [Y.-L. Lai, F.-H. Chiang, C.-H. Lin, T.-C. Yu, Strong distance of complete bipartite graphs, The 19th Workshop on Combinatorial Mathematics and Computation Theory, 2002, pp. 12-16], and give a rigorous proof of a revised conclusion about sdiam(K_m,n).     

基于DEMON线谱的轴频提取方法研究

目标的螺旋桨不同则轴频不相同。轴频是目标的特征之一,可以应用于目标识别当中。本文提出一种改进的高频噪声解调分析(DEMON)方法,能够得到具有明显线谱的DEMON谱;提出最大公约数算法,并给出提取轴频的具体步骤。海试数据实验结果验证了本文所提方法及算法的有效性和可行性。     

大气中霭的组成及对环境的影响

本文对相对湿度75%以上,可见度10 km以外,发生频率较高、目前还没有引起重视的大气悬浮物-霭的化学组成及对环境造成的影响进行了讨论.     

关于3连通图的容错直径和宽直径

容错直径和宽直径是度量网络可靠性和有效性的重要参数．对任意k连通图，它的容错直径Dk不超过宽直径dk,本证明：当D2=2时，d3≤max{D， l，2D3-2}；当D2≥3时，d3≤(D2-1)[2(D2-1)(D3-1)-D2-2] 1．     

Variation of tube diameter and film thickness of capillary columns

This paper briefly surveys three important considerations related to the tube diameter and film thickness. These are the interrelationship of these two parameters through the phase ratio, the different meanings of the term “efficiency”, and the influence of film thickness and tube diameter on sample capacity. Comparative examples are given for columns having different diameters and film thicknesses.     

直径为4的整树

本文给出了直径为4的整树的一个充分条件，并由此给出了直径为4的整树的许多新类．最后提出一些基本的公开问题．     

Effective thermal conductivity of granulated two-phase systems at interstitial air pressures

Considering the htermal conduction through molecular collisions an expression for the effective thermal conductivityλ _e of loose and granular two-phase materials at different interstitial air pressure has been derived. The dependence ofλ _e on pore and particle sizes, characteristic pressure and radiative heat transfer is also discussed. Calculated values ofλ _e of glass beads and loose building materials are compared with reported results.     

高压微射流制备纳米中链脂肪酸脂质体的研究

以中链脂肪酸(MCFA)为模型材料,比较了高压微射流(HPM)、超声波和微孔过滤3种方法处理后的MCFA脂质体,着重研究了HPM的处理压力和处理次数对脂质体的平均粒度、包封率和稳定性的影响。结果表明:相比超声波和微孔过滤法,HPM处理后的MCFA脂质体的平均粒度最小、包封率最高、稳定性良好;在120 MPa压力条件下处理6次时,MCFA脂质体的平均粒度达到最小,为(73.9±10.2)nm,包封率为(52.20±9.57)%;在120 MPa压力条件下处理4次时,包封率和载药量达到最高,分别为(70.64±11.25)%和(9.42±0.83)%,稳定性系数最高,为0.9990±3.6951,平均粒度为(78.9±21.5)nm。