排序方式: 共有109条查询结果,搜索用时 15 毫秒
1.
Zhen Gu Yi-Lun Ying Bing-Yong Yan Hui-Feng Wang Pin-Gang He Yi-Tao Long 《中国化学快报》2014,25(7):1029-1032
Nanopore technique plays an important role in single molecule detection, which illuminates the properties of an individual molecule by analyzing the blockage durations and currents. However, the traditional exponential function is lack of efficiency to describe the distributions of blockage durations in nanopore experiments. Herein, we introduced an exponentially modified Gaussian (EMG) function to fit the duration histograms of both simulated events and experimental events. In comparison with the traditional exponential function, our results demonstrated that the EMG provides a better fit while covers the entire range of the distributions. In particular, the fitted parameters of EMG could be directly used to discriminate the sequence length of the oligonucleotides at single molecule level. 相似文献
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In this article, we investigate Programming Evaluation and Review Technique networks with independently and generally distributed activity durations. For any path in this network, we select all the activities related to this path such that the completion time of the sub-network (only consisting of all the related activities) is equal to the completion time of this path. We use the elapsed time as the supplementary variables and model this sub-network as a Markov skeleton process, the state space is related to the subnetwork structure. Then use the backward equation to compute the distribution of the sub-network's completion time, which is an important rule in project management and scheduling. 相似文献
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Energy spectrum of multi-radiation of X-rays in a low energy Mather-type plasma focus device 下载免费PDF全文
The multi-radiation of X-rays was investigated with special attention to their energy spectrum in a Mather-type plasma focus device (operated with argon gas). The analysis is based on the effect of anomalous resistances. To study the energy spectrum, a four-channel diode X-ray spectrometer was used along with a special set of filters. The filters were suitable for detection of medium range X-rays as well as hard X-rays with energy exceeding 30 keV. The results indicate that the anomalous resistivity effect during the post pinch phase may cause multi-radiation of X-rays with a total duration of 300 ± 50 ns. The significant contribution of Cu-Kα was due to the medium range X-rays, nonetheless, hard X-rays with energies greater than 15 keV also participate in the process. The total emitted X-ray energy in the forms of Cu-K and Cu-K/3 was around 0.14 ± 0.02 (J/Sr) and 0.04 ±0.01 (J/Sr), respectively. The total energy of the emitted hard X-ray (〉 15 keV) was around 0.12± 0.02 (J/Sr). 相似文献
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We present a method by which to determine the bulk viscosity of water from pulse duration measurements of stimulated Brillouin scattering (SBS). Beginning from a common model of Brillouin scattering, the bulk viscosity is shown to play an important role in Brillouin linewidth determination. Pulse durations of SBS back-reflected optical pulses are measured over the temperature range of 5-40℃. SBS linewidths are de- termined via Fourier transformation of the time-domain results, and the bulk viscosity of water is measured and derived from the obtained values. Our results show that the proposed method for measurement of pulse durations is an effective approach for determining bulk viscosity. The method can be easily extended to determine bulk viscosities of other Newtonian liquids. 相似文献
5.
LOSEV V F PANCHENKO Yu N DUDAREV V V IVANOV N G KONOVALOV I N PAVLINSKY A V PUCHIKIN A V 《中国光学与应用光学文摘》2011,(1)
研究了脉冲宽度为25~40 ns的放电脉冲XeCl准分子激光器的工作参数。结果显示,激光器产生的脉冲能量为0.2~0.7 J,重复频率为100 Hz,表明在泵浦功率为2.8~3.3 MW/cm3时,激光器实现了2.6%的激光效率和3.8%的本征效率。 相似文献
6.
In accordance with nonperturbative quantum scattering theory,we investigate photoelectron angular distributions(PADs) from above-threshold detachment(ATD) of negative ions irradiated by circularly polarized few-cycle laser fields.Electrons ejected on the polarization plane demonstrate distinct anisotropies in angular distributions which distinctly vary with the carrier-envelope(CE) phase.The anisotropy is caused by interference between transition channels;it also depends strongly on laser frequency,pulse duration,and kinetic energy of photoelectrons.Optimal emission of photoelectrons,which varies with CE phase,makes it possible to control photoelectron motion. 相似文献
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《数学的实践与认识》2019,(20)
设计了一种搭接网络的新的表示方法,将工序之间的衔接关系等效的转化为搭接关系,并计算所有搭接关系的间隔时间(LAG),且能直接运用搭接网络法则计算时间参数,使新的表示方法具有与单代号网络计划一样的直观性和便利性.另外,利用搭接网络的新表示方法,发现了在搭接网络中"搭接关系组合类型决定了工期与工序持续时间的变化关系"这一奇异现象.通过这一奇异现象提出了研究工期优化的新思路,强化了搭接网络的应用性,使之能够更加科学地指导工程项目的实施,避免因为工期延误导致的损失,并能够扩展到其它类型的网络计划中来. 相似文献
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激光和辐射烧蚀引起的Rayleigh-Taylor(R-T)不稳定性是激光聚变的重要研究课题,本文讨论了R-T不稳定性实验的有关要求,在考虑烧蚀致稳的情况下,对特定的塑料薄膜靶用解析公式计算了R-T不稳定性线性发展阶段的积分增长指数随扰动波长、驱动源强度和持续时间的变化。给出某些感兴趣的物理图象,提供的信息可供有关实验和靶设计参考。 相似文献
10.
We demonstrate a diode-pumped cw mode-locked Nd:YAG by an acousto-optic mode locker. A mode-locked pulse with duration of 345 ps and output power of 12 W is obtained. The resonator design shows three advantages: a larger mode volume, high stability against thermal lens fluctuations, and excellent beam quality with TE00 mode. Different from previous active mode locking designs, we employ a frequency stabilizer and a phase-lock loop circuit to ensure the mode locking stable operation. 相似文献