A far infra-red study of conformational disorder in PTFE

The examination of the 250–350 cm^?1 region of the infra-red spectrum of polytetrafluoroethylene (PTFE) has been extended by studies of thermally degraded and sintered material. We conclude that a band at 277 cm^?1 does not arise from a true mode of the crystal but has its origin in regions where the chain has a bent conformation. Our previous speculation that bands at 292 cm^?1 and 312¹ cm^?1 (Raman active only, for the isolated chain) acquire their weak activity in the infra-red through conformational disorder is confirmed. It is likely that the conformational disorder in question arises from chain folding in the polymer crystal.     

Generalized Model Analysis of Ionizing Radiation Effects in Semiconductor Devices

The necessity of analyzing complex semiconductor device behavior in the radiation environment requires improved analytical methods for accurate representation. The purpose of this discussion is to present work done on the applicability of the Linvill lumped model in a generalized model analysis. The advantages of the lumped model technique include flexibility in detail of device representation (i.e., accuracy), an intimate coupling to the well known radiation effects in bulk semiconductor material, and a unified analytical technique for a wide range of devices. It is shown that the lumped model analysis provides an effective technique for analyzing simple as well as complex devices in a pulsed ionizing radiation environment. Included is the representation of a simple p-n junction diode, a grown-junction transistor; and a planar-diffused transistor with its monolithic-chip substrate and isolation junction. The lumped-model behavior of the diode and grown junction transistor is compared to previously available analytical results. Using measured parameter values, the quantitative lumped-model predictions are compared to experimentally observed transient radiation response. The transistor response is investigated as a function of quiescent emitter current and external base resistance. The effect of the substrate junction in the monolithic-chip transistor is qualitatively presented as a function of the transistor parameters and the substrate proximity.     

Children's generosity as influenced by deservedness of reward and type of recipient.

24 5-6 yr-olds and 24 8-9 yr-olds were given the opportunity to donate money to a charity under conditions varying the characteristics of the recipient (crippled child vs crippled adult) and the situation in which the child acquired the resource for generosity (earned vs windfall). On the basis of previous literature, it was expected that these conditions would affect the age differences often reported in generosity. Contrary to such expectations, there was more generosity toward crippled children than crippled adults across both age groups. There was an increase in generosity with age across conditions, with girls consistently donating more than boys. Methodological issues and reactions to stigmatized others are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of buoyancy on laminar vertical upward flow friction factors in cylindrical tubes

The coupled energy and momentum equations were solved for fully developed vertical upward laminar flow in a cylindrical tube. A simple engineering correlation which agreed well with the analytical solution was obtained. In addition, an effect was obtained and incorporated into a general engineering correlation. Comparison of the general correlation with the existing data was adequate. If the results for a cylindrical tube can be applied to typical wire-wrapped rod bundles in a LMFBR the use of an increased friction factor to account for buoyancy effects in laminar flow is not justified because the maximum value of the Grashof—Reynolds number ratio is small.     

High-resolution cross-sectional imaging of the gastrointestinal tract using optical coherence tomography: preliminary results

BACKGROUND: Optical coherence tomography (OCT) is a novel technique for noninvasive cross-sectional imaging with high spatial resolution (10 to 20 microm). OCT is similar to B-mode ultrasound except that it uses infrared light rather than ultrasound. We studied OCT imaging of the gastrointestinal (GI) tract in vitro to analyze the potential of this technique for endoscopic applications. METHODS: Human gastrointestinal tissues harvested from surgical resection and autopsy specimens were used. Specimens were imaged within 5 hours of resection or snap frozen in liquid nitrogen. After imaging, OCT scan locations were carefully marked using dye microinjections, fixed, and prepared for routine histologic processing. OCT images were then compared and correlated with the histologic sections. RESULTS: OCT images demonstrated clear delineation of the mucosa and submucosa in most specimens. Furthermore, microscopic structures such as crypts, blood vessels, or esophageal glands in the submucosa and lymphatic nodules were observed. CONCLUSIONS: The resolution of OCT images of GI wall is sufficient to delineate the microscopic structure of the mucosa and submucosa. Potentially, OCT would allow in vivo imaging at endoscopy of the microstructure of the mucosa and submucosa. This would be particularly useful in the detection and staging of small lesions such as early stage cancers.     

Application of distributed interactive simulation technology withinthe Department of Defense

The paper focuses on distributed interactive simulation (DIS) as an emerging technology which offers new opportunities for the Department of Defense in the design of simulation systems, the approach to training, and the improvement of the material acquisition process. Discussion of these topics is followed by an overview of selected Department of Defense programs that employ DIS. The paper concludes with a brief discussion of technology challenges that must be overcome for this technology to reach its full potential     

FRP与砌体节点的粘结性能

用FRP加固的无筋砌体墙的面外弯曲和面内剪切性能经常受剥离破坏机理的控制。因而,需要定量确定基本的界面粘结滑移模型,这个模型能够描述FRP与砖砌体粘结界面性能。给出了29个采用外包和嵌入式加固FRP的拔出试验结果,试验变量包括:表面处理方式,几何尺寸,FRP(相对于节点和核心的)位置,基础节点的砌筑方法(砂浆快速干砌),玻璃纤维布的粘结方式,FRP种类。讨论了试验结果,初步给出了实际应用的建议。通过试验数据验证预测界面开裂剥离抗力的模型。该模型在外包和嵌入式加固技术应用中具有普遍的意义。这个一般性模型对所研究的29个拔出试验的极限强度具有很高的预测精度。