山迪亚国家实验室半导体桥(SCB)应用研究概述

山迪亚国家实验室研究的半导体桥（ＳＣＢ）是一种成熟的技术，现由山迪亚用户用于不同用途。由于需要为系统提供体积小、重量轻、成本低，并要求少量电能作用的爆炸组件，由于本报告的目的，我们规定爆炸组件是发火装置和爆炸元件的组合。为此，由于常规点火系统不能满足用户严格的尺寸、重量和能量要求，我们设计并正在研究包括从山迪亚应用的以烟火点火器的ＳＣＢ应用。在本报告中，我们介绍了为用户设计的具有具体实例系统的ＳＣ     

长壁工作面采煤机组实现大功率高产高效

长壁工作面采煤机组实现大功率高产高效【美】Ｊ·ＡＯｒｇａｎｉｓｅａｋ等编者按这是一篇关于美国（实质上也是对全世界）长壁工作面采煤机组十多年来技术进步和今后技术发展态势的综述。我国是以长壁式开采体系为主导的产煤大国，综采、高档普采都发展很快，因此，我们...     

原位反应复合法制备金属基合材料的进展

综述了近年来利用原位反应复合法制备金属基复合材料的最新工艺方法，包括：ＸＤ法、ＶＬＳ法、ＳＨＳ等。讨论其组织与性能，同时还展望了原位反应复合法的发展前景。     

Automated analysis for scintigraphic evaluation of gastric emptying using invariant moments

This study introduces a method for automated analysis of the standard solid-meal gastric emptying test. The purpose was to develop a diagnostic tool to characterize more reproducibly abnormalities of solid-phase gastric emptying. The processing of gastric emptying is automated using geometrical moments that are invariant to scaling, rotation, and shift. Twenty subjects were studied. The first step was to obtain images of the stomach using a nuclear gamma camera immediately after the subject had eaten a radio-labeled meal. The second step was to process and analyze the images by a recently developed automated gastric emptying analysis (AGEA) method, which determines the gastric contour and the geometrical properties include such parameters as area, centroid, orientation, and moments of inertia. Statistical tests showed that some of the moments were sensitive to the patient's gastric status (normal versus abnormal). The difference between the normal and abnormal patients became noticeable approximately 1 h after meal ingestion.     

Optimization of signal detection in SPECT

Parallel-hole collimators of varying design are discussed, using the display signal-to-noise ratio of R.F. Wagner et al. (Med. Phys., vol.6, p.83-94, 1979) to obtain contrast-detail diagrams and analytical expressions for the signal-to-noise ratio in SPECT (single-photon-emission computed tomography). It is concluded: (1) that the detectability of deeply embedded small objects (more than ~10 cm deep) may be improved only slightly by improvements in the resolution and geometric efficiency of parallel-hole collimators; (2) that a long-bore collimator outperforms a low-energy general-purpose collimator for objects smaller than ~2 cm, but only to a minor degree; and (3) that for improvement of small object detectability by SPECT, the most fruitful technological pursuit would probably involve development of focused collimators.     

An observation on quartz resonator aging

Aging and acceleration sensitivity of certain fabrication lots of quartz resonators show a trend that may arise from a common predominating mechanism, such as stresses arising from the mounting structure. The presence or absence of such a trend is discussed. As part of the work on bulk-acoustic-wave (BAW) resonators, a database of all known parameters of the resonators in question was assembled. Resonator processing and electrical parameters were examined for correlations with the acceleration sensitivity. A similar effort was being undertaken in regard to resonator aging, and possible correlations between the aging and acceleration sensitivities of the various resonators were examined. The results for two such fabrication lots are shown. The magnitude of the observed aging was typically in the 10(-10) per day range. The identity of the common contributor is unknown at the present time. It is likely that mounting related stresses are the common contributor.     

Thermoelastic coefficients of alpha quartz

Experimental measurements of alpha quartz thermal expansion as reported in the literature have been critically analyzed. A recommended set of best measured values over the temperature range -50 degrees C to +150 degrees C have been determined, as have values for the coefficient of thermal linear expansion (CTE) and the thermoelastic coefficients. The impact of using the coefficients on determinations of quartz material temperature coefficients and on the calculation of temperature coefficients of frequency for the case of the AT-cut is discussed.