《化工原理》中离心泵安装高度计算中的问题探讨

针对<化工原理>教材中关于离心泵安装高度计算中存在的问题进行了归纳和讨论,并提出了相应的观点.     

从饱和度再认识非饱和表层土吸力

为了探讨非饱和土水膜中的重力水对总吸力的影响,根据饱和度大小情况,将非饱和土中的水、气形态分成了四类,即界限饱和度Sr1,Sr2,Sr3,Sr4.分析了非饱和土中的总吸力组成和水膜中重力水对总吸力的影响,并推导出界限饱和度Sr2条件重力水对总吸力影响的计算公式,在此基础上给出了颗粒级数分别为10-3mm~100mm的总吸力与饱和度的关系图.最后选择了一种试验值模拟比较.模拟比较表明,考虑重力水的作用下理论计算值与实测值更加吻合,从而证实了重力水对吸力的影响是不可忽略的.     

Motion Analysis of Fiber Band in Compact Field of Compact Spinning

The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting angle of suction slot in profile tube, additional twists created by fiber band＇s rotating around its own axis and ultimate twists in compact yarn are deduced accordingly. The existence of additional twists is also verified through experiments.     

高负压吸引治疗慢性化脓性中耳炎40例

目的：观察高负压吸引法治疗慢性化脓性中耳炎的疗效。方法：选择经常规治疗方法难以干耳的慢性单纯性中耳炎40例(46耳)，采用高负压吸引法进行治疗。结果：治愈43耳，其中8耳仅治疗一次即愈，治愈率为93．5％。结论：高负压吸引法是治疗难治性慢性单纯性中耳炎有效、安全的首选方法，值得推广。     

钉螺吸附能力的测试

为了防止钉螺经水渠随水流扩散 ,必须研究钉螺在水中的运动规律 钉螺的吸附力是研究钉螺运动规律的基本数据 介绍了钉螺吸附能力测试方法及内容 ,分析了各种因素对钉螺吸附能力的影响     

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.     

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.     

一拖三变频空调(VRV)系统运行特性的仿真研究

一拖三VRV空调系统由于各蒸发器之间参数的相互影响，使得其运行特性十分复杂。该文采用分布参数法，引用空泡系数，建立起以变频压缩机、三电子膨胀阀、三蒸发器为一体的系统的热力学仿真模型；对系统进行仿真研究，得出不同工况下系统的运行特性。仿真结果表明在一拖三VRV空调系统中进行吸气压力控制的必要性与优越性，为系统的控制方法的制定以及系统的优化设计奠定基础。     

基于PLC现场网络的绞吸式挖泥船监控系统

针对目前国内绞吸式挖泥船自动化 水平较低的情况，提出了一种基于PLC现场网络的绞吸式挖泥船监控系统。该系统以可编程序控制器为处理核心，并通过远程控制网络Controller Link 实现与计算机之间的通信。     

公路清扫车吸尘系统仿真设计

运用计算流体力学技术对高速公路清扫车吸尘系统的流场进行了仿真分析与结构改进。仿真采用有限体积法FVM,利用非结构化网格对吸盘模型进行网格划分,采用k-湍流双方程模型模拟湍流流动。经过分析不同设计方案对吸尘效率的影响,最后得到一个改进的设计方案,大大提高了靠近地面的气流速度,改进了流场分布,提高了吸尘效率,且不会出现气流外泄造成的二次污染,达到了设计要求,为开发具有自主知识产权高效率的公路清扫车做出了重要贡献。