Fluid Mechanics of Biological Surfaces and their Technological Application

 A survey is given on fluid-dynamic effects caused by the structure and properties of biological surfaces. It is demonstrated that the results of investigations aiming at technological applications can also provide insights into biophysical phenomena. Techniques are described both for reducing wall shear stresses and for controlling boundary-layer separation. (a) Wall shear stress reduction was investigated experimentally for various riblet surfaces including a shark skin replica. The latter consists of 800 plastic model scales with compliant anchoring. Hairy surfaces are also considered, and surfaces in which the no-slip condition is modified. Self-cleaning surfaces such as that of lotus leaves represent an interesting option to avoid fluid-dynamic deterioration by the agglomeration of dirt. An example of technological implementation is discussed for riblets in long-range commercial aircraft. (b) Separation control is also an important issue in biology. After a few brief comments on vortex generators, the mechanism of separation control by bird feathers is described in detail. Self-activated movable flaps (=artificial bird feathers) represent a high-lift system enhancing the maximum lift of airfoils by about 20%. This is achieved without perceivable deleterious effects under cruise conditions. Finally, flight experiments on an aircraft with laminar wing and movable flaps are presented.     

Neonatal lung function following mid-trimester amniocentesis

Three hundred and fifty-four women who underwent midtrimester genetic amniocentesis were matched for age, parity, indication, and smoking history, with an equivalent number of women who had declined the procedure, for the purpose of comparing the neonatal respiratory status of their offspring. There was no evidence that the infants exposed to genetic amniocentesis were compromised.     

我国电子商务环境研究

概述了电子商务的定义、特征及其目前的发展情况,着重对我国的电子商务环境进行了分析,简要提出了发展我国电子商务的模式与策略。     

水解酸化＋两级生物接触氧化处理高盐度水产品加工废水

介绍了“水解酸化＋两级生物接触氧化”处理水产品加工废水的运行效果和工程实例，结果表明：对C1^-浓度平均6000mg／L的高盐度水产品加工废水，系统对COD、SS、氨氮的去除率分别超过了88％、90％、85％，出水COD、SS、氨氮分别低于100mg／L、70mg／L、15mg／L，出水完全可以达到《污水综合排放标准》（GB8978—1996）一级排放标准。