A shear horizontal surface acoustic wave sensor for the detection of antigen–antibody reactions for medical diagnosis

In this paper we describe the development of a shear horizontal surface acoustic wave immunosensor for medical diagnostics. There exists a strong interest in the rapid detection of antigen–antibody reactions at small concentrations in the g/ml region in plasma, serum, or whole blood. Sensors whose operating principle is based on shear horizontal acoustic surface waves are well suited for this. We have used a spin-on glass film for the guidance of the surface wave as well as for the protection of the aluminum structures of the surface wave transducers from aggressive analyte liquids. This film has proven to considerably enhance the sensitivity of the device, and to simultaneously provide a durable protection of the transducers. Furthermore, polymers based on polyvinylamines have been used for the first time for immobilization of the capture protein. This technique effectively prevents the undesired binding of foreign substances like cells, non-specific antibodies, or other proteins at the sensor surface.     

敷设声学覆盖层的板架结构抗冲击性能数值计算研究

为提高潜艇的隐身性能,通常在潜艇非耐压壳板外表面敷设消声瓦,在耐压壳体的外表面敷设隔声去耦瓦,在耐压壳体内表面敷设"阻尼层"(以上三种结构统称为多种声学覆盖层);由于声学覆盖层含有空腔的特殊结构形式,该空腔结构形式在受到爆炸冲击波时,腔体将产生变形并吸收能量,这将严重影响潜艇的抗冲击性能。因此,针对敷设声学覆盖层的板架结构的吸能性能进行研究,找出了覆盖层空腔结构变形、速度及加速度与冲击波能量吸收之间的关系,得到敷设声学覆盖层板架结构的抗冲性能;并对声学覆盖层结构进行优化,在此基础上,给出兼具抗冲和隔振功能的声学覆盖层结构设计及性能参数的优化建议。     

The NAL-ISRO acoustic test facility

The Indian Space Programme has the goals of launching a number of communication and remote sensing satellites for various uses. The acoustic exposure testing of such space bound components and systems on ground is mandatory to check their ability to withstand the extreme noise fields encountered during the trans-atmospheric flight to their final destinations in space. This paper outlines the nature and origin of this acoustic field, need for acoustic testing, establishment of a versatile groundbased high intensity acoustic-testing facility and its performance evaluation. The facility was set up as a joint project between the National Aeronautical Laboratory (nal) and the Indian Space Research Organisation (isro).     

Surface acoustic wave measurements of surface cracks in ceramics

An investigation of scattering from surface cracks has been conducted. In particular, the change in the reflection coefficient of a Rayleigh wave incident on a surface indentation crack has been measured as the sample is stressed to fracture. The acoustic measurements have been correlated with the stable crack extension that precedes final failure. The crack extension behavior of as-indented specimens was found to differ appreciably from that of annealed specimens. Cracks in the annealed samples exhibited partial crack tip closure, but little stable extension, whereas cracks in the as-indented samples displayed both crack closure and irreversible crack growth. This behavior has been rationalized by invoking concepts based upon the residual stresses created by indentation.     

Application of the acoustic emission technique to the react and wind processed Nb3Sn superconducting magnet

A technique combining acoustic emission and voltage measurement is applied to quench experiments conducted on a newly fabricated Nb₃Sn superconducting magnet. Based on the results, the training mechanism, epoxy potting effect and conductor degradation due to the electromagnetic force are discussed.     

Computerized evaluation of acoustic images utilizing a method of averaging

A computerized technique is presented which has been developed for analyzing acoustic images of an inhomogeneous material. The acoustic imaging system is briefly described with emphasis on its adaptation to billets of graphite for atmospheric reentry body use. Ultrasonic images of such inhomogeneous material contain a nonuniform distribution of anomalies and few, if any, geometrically regular features which can be assessed to establish material integrity. Results obtained with our new algorithms show, for certain discriminants, a high degree of correlation between the numerical accept/reject values obtained from acoustic image processing and the time-to-failure of the graphitic material in simulated atmospheric reentry tests.     

双层套管井中声波波形分析

用柱状多层理论模型,计算了裸眼井、单层套管井、双层套管井中的声波波形。分别用地层纵波、横波和套管波信息,结合三种模型对双层套管井中不同条件下水泥胶结质量进行了详细分析。指出用内层套管波列和地层波列可定性判断两层套管之间的水泥胶结质量,用外层套管波列和地层波列能判断外层套管和地层之间的水泥胶结质量。结果表明,裸眼井和套管井的声波全波资料综合分析,能较好地评价水泥胶结质量。     

关于一类布尔函数

文献[1]中提出了一类布尔函数,本文讨论了此类布尔函数的密码特性。     

NUMERICALLY SOLVING STRONGLY NONLINEAR PROBLEMS BY MEANS OF NO ITERATIONS

Based on the Homotopy Analysis Method which is a new kind of nonlinear analytic technique proposed in references[2][3][4].a direct numerical technique for strongly non-linear problems is proposed in general. Then an example in fluid mechanics, say, the 2D laminar viscous flow over semi-infinite plate,is used to illustrate its validity and great potential.Different from nearly all traditional numerical methods for nonlinear problems, this approach can give accurate enough approximations of a strongly nonlinear problem even by means of no iterations. Moreover,it can provide a family of iterative formulas which contain the traditional approaches.     

反直升机声引信的声传播问题

通过空气中声传播的规律及声线弯曲对反直升机引信动作区域性的影响，研究结果表明，确定声引信在空中的动作区域半径时须考虑温度和风的垂直分布的影响，才能保障反直升机雷弹系统战斗部的威力有效发挥