CT9800机器操作使用经验介绍

本文重点介绍了在进行CT断层X-线摄影时,如何灵活应用标准、软组织和骨结构等三种重建图像的软件,既能显著缩短图像重建的时间,又不会遗漏病变的影像。     

Performance of absorption refrigeration cycle at maximum cooling rate

The influence of irreversibility of finite-rate heat transfer on the performance of an absorption refrigerator is investigated using an endoreversible cycle model with continuous flow. The cooling rate is adopted as an objective function for refrigerator optimization. The maximum cooling rate and the corresponding coefficient of performance are derived. The optimal performance with respect to heat transfer areas of the refrigerator is analysed. In addition, certain significant conclusions are reached.     

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吐哈油田在总结国内成功经验的基础上，立足先进适用，配套可靠，相继在鄯善、温米、丘陵三大油田建成了鄯善１０＃、鄯善３０＃、温米５０＃、丘陵１２０＃轻烃回收装置，形成了２１０×１０４ｍ３／ｄ的处理规模。根据吐哈油田天然气的物理性质、压力、外输压力要求，采用低温分离法。在轻烃回收发展过程中，经不断完善和改进，现已形成燃气引擎往复式压缩机；分子筛脱水；多股流冷箱换热；重烃逐级降压闪蒸提馏脱水技术；丙烷制冷；膨胀机制冷；导热油供热；ＤＨＸ工艺；屏蔽液烃泵；分布式集散控制系统和安全联锁控制１０项关键技术。     

Postoperative evaluation in mandibular prognathism treated by bilateral sagittal split osteotomy

The present study was undertaken to evaluate the postoperative relapse from the period of unwiring to 1 year postoperatively and its correlation to the amount of mandibular setback and change in vertical dimension after mandibular bilateral sagittal split osteotomy. Twenty-seven patients were evaluated cephalometrically by the time preoperatively, 6 weeks, 6 months and 1 year postoperatively. It was found that 1) the average amount of mandibular setback at pogonion point, 6 weeks postoperatively, is 7.6mm backward and 1.9mm downward, 2) the average amount of horizontal relapse at pogonion point, 6 months and 1 year postoperatively, are 1.9mm and 2.3mm respectively. 86% of the horizontal relapse, 1 year postoperatively, occurs in the first 6 months after removal of intermaxillary fixation, 3) the average amount of vertical relapse at pogonion point, 6 months and 1 year postoperatively, are 0.9mm and 1.1mm upward. 82% of the vertical relapse, 1 year postoperatively, occurs in the first 6 months after removal of intermaxillary fixation, 4) the amount of 1 year postoperatively horizontal relapse is significantly correlated both with the amount of horizontal mandibular set back and vertical downward change (r = 0.58, 0.67, p < 0.001), whereas the amount of vertical relapse is with the vertical downward change only, but horizontal setback isn't.     

Mixing in processing of thermoplastics by extrusion

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 9–11, August, 1993.