A Comparision of Starch Granules as Seen by Both Scanning Electron and Ordinary Light Microscopy

Starch being a transparent crystal often give images which are difficult to precisely define with the light microscope due to the diffraction and other effects such as internal structure which may appear as a surface phenomena. The scanning electron microscope (SEM); however, gives only surface detail. In a effort to differentiate between surface and internal details, the same starch granules have been studied by both ordinary light and scanning electron microscopy. In each case the granules were held in the same configuration as was seen with the light microscope when they were studied by SEM. In this way a direct comparison could be made between granules viewed by each microscopy technique. From such comparisons it is possible to determine the starch details that are actually due to internal features. The results for canna, potato and corn starches are given.     

A Microwave Method for Measuring Changes in Lung Water Content: Numerical Simulation

A numerical procedure to simulate several physiological and geometrical changes occurring during development of edema and to study their effects on the sensitivity of the microwave detection method is presented. The method of solution utilizes a model which consists of a two-dimensional cross section of a thorax. The model is based on an X-ray CAT scan taken with the microwave applicators in place. The electromagnetic boundary value problem is then solved numerically using the method of moments. Numerical results are presented to show the effects of several parameters, such as the uneven water distribution in the lung, the field distribution in the aperture of the microwave transmitter, and the location of the receiver on the sensitivity of the microwave detection method. Based on these results, several suggestions are made to help optimize the sensitivity of the microwave method of measuring changes in lung water content.     

以爱国者的名义!——《生死狙击》DVD赏析

【关于故事】在美国军队中服役多年,且在战场上有过优异表现的狙击手鲍勃·李·斯瓦格在骨子里并不喜欢过这种整日与冰冷的枪械为伴的日子,某次在非洲执行秘密任务的时候,斯瓦格失去了自己的搭档。回国后,斯瓦格离开了军队,带着自己忠实的爱犬来到了偏僻的阿肯色州,开始了隐居的日子。然而,斯瓦格宁静的生活并未持续多久便被无情地打破了。一天,一群国防部的官员找到了斯瓦格,希望他凭借多年的狙击经验,在美国     

GD&T-Based Characterization of Short-Range Non-contact 3D Imaging Systems

We present a series of test metrics, artifacts, and procedures for characterizing and verifying the operating limits of a short-range non-contact three-dimensional imaging system. These metrics have been designed to correspond to dimensioning and tolerancing metrics that are widely used in industry (e.g. automotive, aerospace, etc.). We introduce operating limit metrics that correspond with the geometric dimensioning and tolerancing (GD&T) metrics of Form (Flatness and Circularity), Orientation (Angularity), Location (Sphere, Corner, and Hole Position Errors), and Size (Diameter, Sphere-spacing, Plane-spacing and Angle Errors). An example is presented to illustrate how these metrics, artifacts, and associated test procedures can be used in practice.     

Reconceptualizing constructivism: Developing a personalized approach to STS science education

Derek Hodson. (1998). Teaching and learning science: Towards a personalized approach. Buckingham, UK: Open University Press. Pp. 208. ISBN 0–335–20115–6 (paper), £17.99.