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本文讨论水平圆管中幂率流体的起动问题。用显式和隐式两种格式,我们得到了问题的数值解并从而得到流动建立时间的近似公式。  相似文献   
2.
A GEANT4-based Monte-Carlo (MC) model is developed to study the performance of endcap time-of-flight (ETOF) at BESⅢ. It's found that the multiple scattering effects, mainly from the materials at the MDC endcap, can cause multi-hit on the ETOF's readout cell and significantly influence the timing property of ETOF. A multi-gap resistive plate chamber (MRPC) with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate (per channel), from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF, depending on the readout pad size used. The timing performance of an MRPC ETOF is also improved. These simulation results suggest and guide an ETOF upgrade effort at BESⅢ.  相似文献   
3.
体外膜肺氧合(extracorporeal membrane oxygena-tion,ECMO)作为一种有效的心肺支持治疗手段,可以减轻心肺功能负荷,有效改善低氧血症,避免长期高浓度氧吸入所致的氧中毒及机械通气的气道损伤,同时还可以为心脏功能提供暂时辅助支持,增加心排出量,改善全身循环灌注,维持心肺循环稳定,为心肺功能的恢复赢得时间[1-2]。赵举等[3]报道2002-2010年期间,在国内6家医疗中心,339例ECMO病例中,用于单纯呼吸支持65例,心脏支持248例,体外心肺复苏26例。总体脱机率63%,成功出院率26%,心脏支持的应用多于呼吸支持。本科室2011年引进ECMO设备,通过观察和分析ECMO在数种肺部疾病中的应用结果,现对其临床应用价值,探讨如下。  相似文献   
4.
This paper describes a way of solving the reservoir simulation pressure equation using multigrid technique.The subroutine MG of four-grid method is presented.The result for2-D two-phase problem is exactly the same as that of the SOR method and the CPU time is much less than that of the latter one.  相似文献   
5.
油气藏两相渗流问题的多重网格法   总被引:2,自引:0,他引:2  
油气藏数值模拟要解一套高维、非线性、奇异、不定常方程组,工作量很大.本文讨论非线性椭圆-抛物方程的多重网格算法,给出了四重网格计算子程序,并把它用于底水气田计算,与SOR法比较,计算结果完全相同,计算效率显著提高。  相似文献   
6.
In order to test the performance of detector prototypes in a laboratory environment, we design and build a large area (90 cm×52 cm) test platform for cosmic rays based on a well-designed Multi-gap Resistive Plate Chamber (MRPC) with excellent time resolution and a high detection efficiency for minimum ionizing particles. The time resolution of the MRPC module used is tested to be ~80 ps, and the position resolution along the strip is ~5 mm, while the position resolution perpendicular to the strip is ~12.7 mm. The platform constructed by four MRPC modules can be used for tracking cosmic rays with a spatial resolution of ~6.3 mm, and provide a reference time ~40 ps.  相似文献   
7.
A new prototype of large area Multi-gap Resistive Plate Chamber (MRPC) with long readout strips was built. This Long-strip Multi-gap Resistive Plate Chamber (LMRPC) is double stacked and has ten 250 μm-thick gas gaps. Signals are read out from the two ends of each strip with an active area of 50 cm×2.5 cm in each. The detector was tested at FOPI in GSI, using the secondary particles of proton beams (E=3.5 GeV) colliding with a Pb target. The results show that the LMRPC prototype has a time resolution of about 60-70 ps; the detecting efficiency is over 98% and the ratio of cross-talk is lower than 2%. The detector also has a good spatial resolution of 0.36 cm along the strip direction.  相似文献   
8.
尼龙亲和膜色谱法纯化半胱氨酸蛋白酶抑制剂   总被引:1,自引:0,他引:1  
建立了一种快速、简便的分离半胱氨酸蛋白酶抑制剂的方法,尼龙膜经壳聚糖改性后,以木瓜蛋白酶为配基制备了一种新型的蛋白质分离材料,并研究了此分离材料的物理及化学性能。所得到的亲和膜上固定化木瓜蛋白酶的热稳定性提高,最适催化温度为55℃,最适pH值为8.0,米氏常数为353.8 g/L;将该亲和膜应用于半胱氨酸蛋白酶抑制剂的分离纯化,在对洗脱液、洗脱速度进行优化的基础上,成功的分离纯化出半胱氨酸蛋白酶抑制剂,纯化倍数为7.25倍。  相似文献   
9.
本文对多相流场方程的研究方法和理论模型作了介绍和分类,得到了欧拉型的时间平均和体平均的场方程。   相似文献   
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