目的建立一种适用于中草药辐照检测方法。方法对白蔻、紫苏、忍冬藤、甘草与荷叶5种中草药样品分别在4 k Gy、5 k Gy及10 k Gy剂量下进行辐照处理,同时以未辐照样品作为对照。辐照后分别测试每份样品的直接落射荧光计数单位(DEFT值)和...目的建立一种适用于中草药辐照检测方法。方法对白蔻、紫苏、忍冬藤、甘草与荷叶5种中草药样品分别在4 k Gy、5 k Gy及10 k Gy剂量下进行辐照处理,同时以未辐照样品作为对照。辐照后分别测试每份样品的直接落射荧光计数单位(DEFT值)和细菌总数(APC值),并计算DEFT值与APC值之差(Dc值),将该差值与特定阈值比较判定样品辐照情况。结果随辐照剂量增加,DEFT值差异不显著,DEFT值分别为0 k Gy:6.9~9.0,4 k Gy:6.8~8.7,5 k Gy:6.7~8.9,10 k Gy:6.9~9.0;APC值逐渐降低,APC值分别为0 k Gy:6.0~7.8,4 k Gy:3.8~5.6,5 k Gy:3.2~5.5,10 k Gy:1.2~3.7;辐照后4组样品之间Dc值差异显著,4 k Gy、5 k Gy、10 k Gy及0 k Gy下辐照处理样品的Dc均值分别为2.6~4.9,3.0~5.3,5.3~7.3和0.4~2.0。结论当阈值设定为3.0时,可检测出5.0 k Gy及5.0 k Gy以上辐照处理样品。展开更多
目的:研究和评价实用单克隆抗体SPA红细胞花环直接法(简称实用McAb‐A‐E直接法)检验 T淋巴细胞亚群细胞涂片细胞计数随机误差,并与M cA b‐A‐E直接法原方法比较。方法随机选取20例样本,在涂片的2/6~4/6区域间至少2个区计数20...目的:研究和评价实用单克隆抗体SPA红细胞花环直接法(简称实用McAb‐A‐E直接法)检验 T淋巴细胞亚群细胞涂片细胞计数随机误差,并与M cA b‐A‐E直接法原方法比较。方法随机选取20例样本,在涂片的2/6~4/6区域间至少2个区计数200个细胞,计数区域不重复,CD4+和CD8+连续计数4次,CD3+连续计数2次。结果实用M cA b‐A‐E直接法细胞计数随机误差分别为CD3+:7.86,CD4+:9.99,CD8+:8.55,CD4+/CD8+:0.33,低于 M cA b‐A‐E直接法原方法误差,即CD3+:15.00,CD4+:13.80,CD8+:10.70,CD4+/CD8+:0.69。结论实用M cA b‐A‐E直接法细胞计数随机误差小于M cA b‐A‐E直接法原方法。展开更多
In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were ...In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were determined with the use of statistical theory of unimolecular reactions using various approximations. In our work, we used the products frequencies instead of transitions frequencies in the calculation of unimolecular dissociation rates obtained by three models RRKM. The agreement between the experimental cross section ratio and calculated rate ratio with direct count approximation seems to be reasonable.展开更多
文摘目的建立一种适用于中草药辐照检测方法。方法对白蔻、紫苏、忍冬藤、甘草与荷叶5种中草药样品分别在4 k Gy、5 k Gy及10 k Gy剂量下进行辐照处理,同时以未辐照样品作为对照。辐照后分别测试每份样品的直接落射荧光计数单位(DEFT值)和细菌总数(APC值),并计算DEFT值与APC值之差(Dc值),将该差值与特定阈值比较判定样品辐照情况。结果随辐照剂量增加,DEFT值差异不显著,DEFT值分别为0 k Gy:6.9~9.0,4 k Gy:6.8~8.7,5 k Gy:6.7~8.9,10 k Gy:6.9~9.0;APC值逐渐降低,APC值分别为0 k Gy:6.0~7.8,4 k Gy:3.8~5.6,5 k Gy:3.2~5.5,10 k Gy:1.2~3.7;辐照后4组样品之间Dc值差异显著,4 k Gy、5 k Gy、10 k Gy及0 k Gy下辐照处理样品的Dc均值分别为2.6~4.9,3.0~5.3,5.3~7.3和0.4~2.0。结论当阈值设定为3.0时,可检测出5.0 k Gy及5.0 k Gy以上辐照处理样品。
文摘目的:研究和评价实用单克隆抗体SPA红细胞花环直接法(简称实用McAb‐A‐E直接法)检验 T淋巴细胞亚群细胞涂片细胞计数随机误差,并与M cA b‐A‐E直接法原方法比较。方法随机选取20例样本,在涂片的2/6~4/6区域间至少2个区计数200个细胞,计数区域不重复,CD4+和CD8+连续计数4次,CD3+连续计数2次。结果实用M cA b‐A‐E直接法细胞计数随机误差分别为CD3+:7.86,CD4+:9.99,CD8+:8.55,CD4+/CD8+:0.33,低于 M cA b‐A‐E直接法原方法误差,即CD3+:15.00,CD4+:13.80,CD8+:10.70,CD4+/CD8+:0.69。结论实用M cA b‐A‐E直接法细胞计数随机误差小于M cA b‐A‐E直接法原方法。
文摘针对当前时间间隔测量存在精度低、分辨率低、测量时间间隔范围小的问题,本文设计了一种高精度、高分辨率的时间间隔测量电路.通过6个D触发器构成的组合逻辑电路和时序逻辑电路,将待测时间间隔t拆分为大于时钟周期的大时间间隔t^(12)与小于时钟周期的小时间间隔t^(1)和t^(2).FPGA在外部时钟的驱动下,采用直接计数法由内部计数器直接计数获取计数值Q,并与时钟周期相乘计算得到t^(12);采用时间-幅度转换法,将t^(1)和t^(2)作为高速开关的开断信号来控制电容的放电时间,实现了时间测量转换为模拟电压测量;使用16 bit高分辨率的ADC对电容放电前后的电压进行采集,结合电容放电前后的压差和恒流源下电容放电公式可得高分辨率的t^(1)和t^(2);最后将测量的t^(1),t^(2)和t^(12)传给上位机计算可得待测时间间隔t.理论分析和实验测量结果表明,电路时间间隔测量范围可达到106 s,分辨率优化到1.5 ps,测量精度达到10 ps.
文摘In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were determined with the use of statistical theory of unimolecular reactions using various approximations. In our work, we used the products frequencies instead of transitions frequencies in the calculation of unimolecular dissociation rates obtained by three models RRKM. The agreement between the experimental cross section ratio and calculated rate ratio with direct count approximation seems to be reasonable.