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公开(公告)号:US6094469A
公开(公告)日:2000-07-25
申请号:US176444
申请日:1998-10-21
申请人: John Dobbs , Ruvin Deych , James Bowers
发明人: John Dobbs , Ruvin Deych , James Bowers
CPC分类号: A61B6/583 , A61B6/4021 , G01N23/04 , H05G1/02 , Y10S378/901
摘要: A computed tomography system having a fourfold improvement in both short-and long-term beam position stability. A beam-position detector is located at a peripheral edge of the primary fan beam and is fixed relative to the primary detectors so as to indicate beam position on the primary detectors. The beam-position detector is oriented so that its maximum sensitivity to beam motion is in the direction of beam movement due to focal spot drift due to thermal effects and gravity. Short-term focal spot drift is detected by a secondary beam out of the primary fan beam and is corrected in real time by adjusting the position of a collimator for the primary beam. Long-term changes in the focal spot position are corrected by using information from the beam-position detector to recalibrate the focal spot-beam collimator data set.
摘要翻译: 一种计算机断层摄影系统在短波长和长波束位置稳定性方面具有四倍的改善。 光束位置检测器位于主风扇光束的外围边缘处,并且相对于主检测器固定,以便指示主检测器上的光束位置。 光束位置检测器被定向成使得由于热效应和重力引起的焦斑漂移,其对光束运动的最大灵敏度在光束移动的方向上。 通过次级光束从主风扇光束中检测出短焦点漂移,并通过调整主光束的准直仪的位置实时校正。 通过使用来自光束位置检测器的信息来校正焦斑位置的长期变化,以重新校准焦点光束准直仪数据集。
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公开(公告)号:US06670278B2
公开(公告)日:2003-12-30
申请号:US09820726
申请日:2001-03-30
申请人: Si Yi Li , Helen H. Zhu , S. M. Reza Sadjadi , David R. Pirkle , James Bowers , Michael Goss
发明人: Si Yi Li , Helen H. Zhu , S. M. Reza Sadjadi , David R. Pirkle , James Bowers , Michael Goss
IPC分类号: H01L21302
CPC分类号: H01L21/7681 , H01L21/31116 , H01L21/76807
摘要: The invention provides a process for plasma etching silicon carbide with selectivity to an overlapping and/or underlying dielectric layer of material. The etching gas includes a hydrogen-containing fluorocarbon gas such as CH3F, an oxygen-containing gas such as O2 and an optional carrier gas such as Ar. The dielectric material can comprise silicon dioxide, silicon nitride, silicon oxynitride or various low-k dielectric materials including organic low-k materials. In order to achieve a desired selectivity to such dielectric materials, the plasma etch gas chemistry is selected to achieve a desired etch rate of the silicon carbide while etching the dielectric material at a slower rate. The process can be used to selectively etch a hydrogenated silicon carbide etch stop layer or silicon carbide substrates.
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公开(公告)号:US06289745B1
公开(公告)日:2001-09-18
申请号:US09305266
申请日:1999-05-04
申请人: James Bowers
发明人: James Bowers
IPC分类号: G01F146
CPC分类号: G01F1/46
摘要: Disclosed is a high temperature insertion type flow element and mounting extension assembly for a gas flow measuring device. Designed to overcome the drawbacks associated with compensating for differential thermal expansion between the element and the duct wall, the element consists of an otherwise conventional insertion type flow element, that incorporates the use of a mounting extension assembly and an expansion fitting. The mounting extension positions the element head in an offset manner from the gas duct, placing the element head in a position away from any insulating materials encasing the duct, allowing for convenient access to the instrumentation and cleaning ports. The expansion fitting stabilizes the element tubes within the duct while absorbing any differential thermal expansion.
摘要翻译: 公开了一种用于气流测量装置的高温插入式流动元件和安装延伸组件。 旨在克服与补偿元件和管道壁之间的差分热膨胀相关的缺点,该元件由另外常规的插入型流动元件组成,其包括使用安装延伸组件和膨胀配件。 安装延伸件将元件头以偏移的方式从气体管道定位,将元件头放置在远离包围管道的任何绝缘材料的位置,从而方便地访问仪器和清洁端口。 膨胀配件在吸收任何不同的热膨胀的同时稳定管道内的元件管。
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