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GPS时间比对机对天文预测图像的时间定标 被引量:1
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作者 谭征 史习昭 《紫金山天文台台刊》 北大核心 1998年第4期75-85,共11页
本文介绍了GPS时间比对机利用GPS时标为基准 ,对天文图像进行时间定标的设计原理、可能出现的各种差错和纠正方法、模拟实验和主要误差分析。时间定标精度为 1 .0 85微秒 ,其均方根为 0 .5
关键词 GPS时间 时间比对 时间定标 天文预测图像
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用次级束流对硅望远镜的时间和能量定标
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作者 贺智勇 Steckmeyer JC +21 位作者 Kerambrun A Angelique JC Bizard G Brou R Cussol D Patry JP Peter J Regimbart R Tamain B Vient E Cabot C Auger G Crema E Peghaire A Saint-Laurent F Gonin M Hagel K Wada R Eudes P Lebrun C Rosato E Masri Y El 《核技术》 CAS CSCD 北大核心 1993年第12期705-709,共5页
利用95MeV/u的^(16)O束产生的次级束流对半导体硅探测器进行了时间和能量定标。实验结果表明,由于次级束流提供的次级粒子种类多,飞行距离长,因此,能给探测器带来非常精确的定标。
关键词 时间定标 能量定标 探测器 定标
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X射线分幅相机电脉冲时标方法研究 被引量:2
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作者 曹柱荣 丁永坤 +5 位作者 张海鹰 刘慎业 缪文勇 易荣清 白小红 刘百玉 《光子学报》 EI CAS CSCD 北大核心 2009年第3期536-540,共5页
在神光II装置上,利用选通脉冲与激光脉冲在示波器上的时间关联建立了一套X射线分幅相机的时间定标方法.以激光打靶的第一分幅像为定标点,由对应的电脉冲关系得到定时的基准.采用四路260J、1ns、0.35μm的激光打击镀金球靶的分幅照相,确... 在神光II装置上,利用选通脉冲与激光脉冲在示波器上的时间关联建立了一套X射线分幅相机的时间定标方法.以激光打靶的第一分幅像为定标点,由对应的电脉冲关系得到定时的基准.采用四路260J、1ns、0.35μm的激光打击镀金球靶的分幅照相,确定了X射线发射在MCP微带线上的基准点,时标准确度为50ps.在惯性约束聚变背光照相实验中,该时标系统得到成功应用. 展开更多
关键词 X射线分幅相机 时间定标 选通脉冲 惯性约束聚变
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Advances in diagnosis, treatment and palliation of pancreatic carcinoma: 1990-2010 被引量:32
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作者 Chakshu Sharma Karim M Eltawil +2 位作者 Paul D Renfrew Mark J Walsh Michele Molinari 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第7期867-897,共31页
Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it ... Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it is the fourth leading cause of cancer related mortality. Most patients present with obstructive jaundice, epigastric or back pain, weight loss and anorexia. Despite improvements in diagnostic modalities, the majority of cases are still detected in advanced stages. The only curative treatment for PC remains surgical resection. No more than 20% of patients are candidates for surgery at the time of diagnosis and survival remains quite poor as adjuvant therapies are not very effective. A small percentage of patients with borderline non-resectable PC might benefit from neo-adjuvant chemoradiation therapy enabling them to undergo resection; however, randomized controlled studies are needed to prove the benefits of this strategy. Patients with unresectable PC benefit from palliative interventions such as biliary decompression and celiac plexus block. Further clinical trials to evaluate new chemo and radiation protocols as well as identification of genetic markers for PC are needed to improve the overall survival of patients affected by PC, as the current overall 5-year survival rate of patients affected by PC is still less than 5%. The aim of this article is to review the most recent high quality literature on this topic. 展开更多
关键词 DIAGNOSIS EPIDEMIOLOGY PALLIATION Pancreatic cancer THERAPY
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Focusing with the decomposition of the time reversal operator method in noisy environments 被引量:1
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作者 Chun-xiao LI Jian-long LI +1 位作者 Xian-yi GONG Ming-fei GUO 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第7期997-1008,共12页
This paper presents a detailed analysis of the effects of noise (reverberation) on the focusing performance of de-composition of the time reversal operator (DORT) in a noise-limited case and in a reverberation-limited... This paper presents a detailed analysis of the effects of noise (reverberation) on the focusing performance of de-composition of the time reversal operator (DORT) in a noise-limited case and in a reverberation-limited case, respectively. Quantitative results obtained from simulations and experiments are presented. The results show the DORT method can be effi-ciently applied to target detection with enough source level to yield significant backscatter. For a target placed on the bottom, the influence of the reverberation on the focusing performance is slight. However, distinguishing between a target and constant backscattering returning from strong local clutter on the bottom (false alarms) needs further research. 展开更多
关键词 Decomposition of the time reversal operator (DORT) Time reversal mirror Retrofocusing performance
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