考虑基质吸力影响的非饱和均质边坡稳定性分析

控制吸力条件下非饱和土的强度特性主要基于膨胀土,文章针对侯禹高速公路某边坡黄土进行控制吸力固结不排水三轴剪切试验,主要研究了有效应力强度参数黏聚力c和内摩擦角φ随基质吸力的变化规律,并基于强度折减法对一定基质吸力影响下的该边坡进行稳定性分析。结果表明:黏聚力c随基质吸力的增大变化明显,而内摩擦角φ随基质吸力的增大基本不变;随基质吸力的增大安全系数增大;在低吸力阶段,增大幅度较大,随基质吸力的增大,增大幅度变小。     

变频转子式压缩机降低吸气干度对容积效率的影响

利用变频滚动转子式压缩机实验台测量了吸气干度x>0.9时压缩机的容积效率.结果表明,当0.90.95)和额定转速时,容积效率仅下降1%,因此,此类压缩机适合用于少量吸气带液的运行.     

基于全耦合模型和管土作用模型的深海悬链线立管触地区域疲劳特性分析

利用建立的浮体、立管和系泊索全耦合模型预报悬链线立管(SCR)的顶端响应,并作为立管详细有限元模型的顶端边界条件,进行疲劳响应分析.在全局有限元分析中,SCR与海床的相互作用通过开发的触地单元模拟,该单元能够考虑海床吸力的产生和释放过程,以及海床沟槽的形状.针对不同的海床参数,计算了SCR触地区域的响应,并通过雨流计数法进行了疲劳损伤分析,得到了触地区域的疲劳损伤对海床参数的敏感性.     

The anatomy and attachment mechanism of the haptor of a Capsala sp. (Platyhelminthes: Monogenea: Capsalidae) on the blue marlin,Makaira nigricans (Istiophoridae)

The muscular anatomy and fine structure of the haptor of a monogenean, Capsala sp., together with an observational distribution study, are described from specimens collected from the dorsolateral and ventral surfaces of the blue marlin, Makaira nigricans. The haptor is composed of seven loculi, which are arranged around a central pair of accessory sclerites. Marginal hooklets and hamuli were not observed. The presence of an outline left by the haptor on the host's skin and the lack of evidence of an adhesive secretion suggested that the haptor attaches primarily by suction. Tendons originating in the extrinsic peduncle muscles insert, via a proximal notch in the accessory sclerites, into the basal tegumental lamina on the ventral surface of the haptor. On contraction the centre of the haptor is thought to be drawn upwards both directly by the extrinsic tendons in the haptoral wall but also by the accessory sclerites which are brought into a vertical position. This increases the volume beneath the haptor, consequently reducing the pressure and thus producing suction. The ribbed marginal valve prevents the inward movement of water. Intrinsic circular and radial muscles in the haptoral wall are also thought to produce suction by drawing the haptoral wall inwards, again increasing the volume beneath and causing a pressure reduction. It is suggested that interconnecting fibres observed between the intrinsic muscles may store elastic energy, allowing Capsala sp. to maintain suction attachment without having constantly to contract its muscles. Papillae on the inner ( = ventral) surface of the haptor are suggested to aid attachment by firstly spreading the negative pressure over the inner surface of the haptor and, secondly, through resisting the shear forces encountered as the fish swims. Both functions are achieved by increasing the surface area of contact with the host's skin, and therefore the frictional forces. Theoretical estimates of the suction efficiency indicate that suction is double the maximum theoretical drag forces which would be experienced by Capsala sp. when M. nigricans is swimming at speeds of both 1 and 20 m s^?1 and suggests that suctorial attachment is efficient. The distribution of Capsala sp. is not thought to be restricted by the surface topography of the host, demonstrated by the fact that individuals were located in both the roughest and smoothest areas of the marlin's skin surface. Distribution is therefore thought to be influenced by other factors such as hydrodynamics, nutritional value of the attachment site, immunological restrictions or cross‐fertilization between parasites.     

海上风力发电机桶形基础竖向初始动阻抗影响因素分析

利用ABAQUS大型通用有限元软件,建立弹性半空间中的海上风力发电机桶形基础(简称桶基)有限元模型。将数值解与已有解析解对比,验证桶基数值模型的准确性。并研究不同因素对桶基竖向初始动阻抗的影响,以及桶基与桶壁壳基础初始动阻抗的关系。结果表明,桶基长径比、桶基厚径比、土体泊松比、土体剪切模量、土体非均匀性对初始动阻抗影响明显,桶基材料对初始动阻抗影响不大;桶基和桶壁壳基础初始动阻抗基本重合,桶基可以退化为桶壁壳基础进行模拟。     

绞吸式挖泥船的疏浚优化---优化策略

本课题以900m/h绞吸式挖泥船为对象,针对其疏浚模型,以土方量为优化目标,提出了一种基于遗传算法的绞吸式挖泥船的优化控制策略,并将推出的工艺参数值作为疏浚控制中的参考值。     

基于相对差商法的吸力式海上风车筒基基础优化设计

确保海上风车基础的稳定且便于海上施工作业是吸力式海上风车基础设计的关键点.论文在分析影响筒基基础稳定性及海上施工难度的设计参数的基础上,建立了以吸力式筒基基础总重量与单筒直径的线性加权函数为目标函数、以单筒直径、入泥深度、筒体个数等参数为设计变量、以基础稳定性为约束条件的吸力式海上风车筒基基础优化设计模型,并将相对差商法的数学优化方法应用于该模型.文中建立的评估模型对其它筒基基础方案设计具有参考价值.     

ATM网络业务量控制中的漏桶算法

讨论了漏桶算法的基本原理 ,并提出在实际应用中应注意的一些问题     

模糊逻辑在ATM网络实时流量控制中的应用

提出了一种模糊逻辑控制系统，能实时处理ＡＴＭ网络中的流量问题。文中使用峰值速率和突发时间长度来描述业务源特性，并据此动态地调节令牌速率。与传统的漏桶算法相比，该系统能透明传输符合流量协议的业务源，并能对业务源的违约行为迅速而有效地作出反应。     

非饱和玄武岩残积土剪切特性试验研究

非饱和土中的基质吸力对其抗剪强度特性有重要的影响。选取贵州毕威高速公路沿线的玄武岩残积土样,采用非饱和直剪仪进行控制基质吸力的剪切试验。试验结果表明,在不同的基质吸力和净法向应力作用下,重塑试样由于结构性遭到彻底破坏,应力应变关系表现为应变硬化型。在300 kPa的基质吸力范围内,基质吸力对黏聚力影响显著,对有效内摩擦角基本无影响。非饱和玄武岩残积土的抗剪强度与基质吸力基本呈线性关系,非饱和抗剪强度参数φ~b=19.4°,验证了非饱和土双应力状态变量抗剪强度公式的适用性。