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A modified distorted-wave Born approximation (DWBA) method is used to calculate the triple differential cross sections (TDCSs) in a coplanar asymmetric geometry for the electron impact single ionization of a He (1s2) atom at intermediate and lower energies. The post-collision interaction and the polarization effect in (e, 2e) collisions of helium are considered in the calculations. The polarization potentials from the damping method and density functional theory (DFT) are compared. Theoretical results are compared with the recent experimental data. 相似文献
94.
实验室条件下研究了Zeocin、两性霉素B(Amphotericin B)、G418、氯霉素(Cm)、氨苄青霉素(Amp)、卡那霉素(Km)、链霉素(Str)7种基因工程常用抗生素对裂殖壶菌(Schizochytrium limacinum)生长的影响。结果表明:S.limacinum对Zeocin最为敏感,在2.5~4mg.L-1 Zeocin中成活率降至2.10%~2.79%(P<0.01);对两性霉素B、G418、Cm较敏感,在14~20mg.L-1两性霉素B中的成活率降至5%以下(P<0.01),在140mg.L-1G418中的成活率为2.08%(P<0.01),在25.5~68mg.L-1 Cm中成活率为13%左右(P<0.05);对Amp,Km,Str不敏感,50~300mg.L-1的Amp,Km,Str不能抑制其生长,成活率仍在80%以上(P>0.05). 相似文献
95.
以碘作催化剂, 无水苯为溶剂, 六乙基亚磷酰三胺依次与羟乙基替加氟、1-芳硒基甘油及硫反应, 得中间体硒代环甘油磷脂替加氟缀合物2a~2f. 以无水N,N-二甲基甲酰胺(DMF)作溶剂, 室温下, 叠氮化钠中对2a~2f进行亲核开环, 得到O-(1-芳硒基-3-叠氮基)异丙基-O-2-(N3-替加氟)乙基硫代磷酯. 体外活性测试结果表明, 目标化合物3a~3f 对膀胱癌细胞PGA1抑制作用比替加氟高, 对胃癌细胞BGC-823的抑制作用与替加氟相当. 相似文献
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贾卢魁 毛泽普 李卫东 曹国富 曹学香 邓子艳 何康林 刘春燕 刘怀民 刘秋光 马秋梅 马想 邱进发 田浩来 王纪科 伍灵慧 袁野 臧石磊 张长春 张雷 张瑶 朱凯 邹佳恒 《中国物理 C》2010,34(12):1866-1873
In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber (MDC), a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data. 相似文献
98.
A diode-end-pumped electro-optic (EO) Q-switched green laser operating at the repetition rate of 20 kHz is reported. A block of La3Ga5SiO14 (LGS) single crystal is used as a Q-switch and the type I phase- matching LiB305 (LBO) is used as the nonlinear crystal in the second harmonic generation. The 2.3-W average power of 532-nm green laser is obtained at the repetition rate of 20 kHz with the pulse width as short as 10 us. When the output power is about 1.5 W, the measured power fluctuation is less than 1.4% (root-mean-square. RMS) with the beam quality factor of M^2 〈 2 in both orthogonal directions. 相似文献
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A new decay detection system with high detection efficiency and low detection threshold has been developed for charged-particle decay studies, including -delayed proton, decay or direct proton emission from proton-rich nuclei. The detection system was tested by using the -delayed proton emitter 24Si and was commissioned in the decay study of 22Si produced by projectile fragmentation at the First Radioactive Ion Beam Line in Lanzhou. Under a continuous-beam mode, the isotopes of interest were implanted into two double-sided silicon strip detectors, where the subsequent decays were measured and correlated to the preceding implantations by using position and time information. The system allows to measure protons with energies down to about 200 keV without obvious background in the proton spectrum. Further application of the detection system can be extended to the measurements of -delayed proton decay and the direct proton emission of other exotic proton-rich nuclei. 相似文献