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31.
For an energy transfer network, the irreversible depletion of excited electron energy occurs through either an efficient flow into an outer energy sink or an inefficient decay. With a small decay rate, the energy transfer efficiency is quantitatively reflected by the average life time of excitation energy before being trapped in the sink where the decay process is omitted. In the weak dissipation regime, the trapping time is analyzed within the exciton population subspace based on the secular Redfield equation. The requirement of the noise-enhanced energy transfer is obtained, where the trapping time follows an exact or approximate 1/Γ-scaling of the dissipation strength Γ. On the opposite side, optimal initial system states are conceptually constructed to suppress the 1/Γ-scaling of the trapping time and maximize the coherent transfer efficiency. Our theory is numerically testified in four models, including a biased two-site system, a symmetric three-site branching system, a homogeneous onedimensional chain, and an 8-chromophore FMO protein complex. 相似文献
32.
We show a scheme of preparing multipartite W type of maximally entangled states among many atomic ensembles with the generation time increasing with the party number only polynomially. The scheme is based on laser manipulation of atomic ensembles and single-photon detection, and fits well the status of the current experimental technology. We also show one of the applications of this kind of W state, demonstrating Bell theorem without inequalities. 相似文献
33.
周泉丰陆元荣朱昆颜学庆刘戈郭之虞陈佳洱 《强激光与粒子束》2013,(B05):124-128
为了提高射频四极场加速器(RFQ)的束流传输效率,需要对纵向分布不均匀的极间电压进行补偿,并且准确测量束流实验中极间电压的绝对数值。考虑到极间电压分布不均匀是由于分布电容和端部效应造成的,而采用调谐块可以调节分布电感,通过电磁场数值模拟研究了调谐块对极间电压分布的影响,最终极间电压的平整度被调整到优于95%。在束流实验中,通过测量轫致辐射谱测定了极间电压的数值,通过束流动力学模拟研究了多能峰产生的原因,并最终标定了70kV极间电压对应的输入功率值284kW。 相似文献
34.
线性方程组二级迭代法的收敛性 总被引:9,自引:0,他引:9
线性方程组二级迭代法的收敛性曹志浩(复旦大学)CONVERGENCEOFTWO-STAGEITERATIVEMETHODSFORTHESOLUTIONOFLINEARSYSTEMS¥CaoZhi-bao(FudanUniversity)Abstrac... 相似文献
35.
在2001~2002年4~7月份对宁波镇海区鸟类资源进行了初步调查。共记录鸟类85种。隶属11目25科.鸟类区系组成具有南北混杂过渡特征。繁殖鸟的区系分析表明鸟类区系归属东洋界.鸟类在不同生态环境的分布存在差异。调查显示本区鸟类以针阔混交林分布种类最为丰富.还讨论了人为干扰对鸟类分布的影响. 相似文献
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A Stable Vector for High-Level Expression and Secretion of Human Interferon αA in Yeast 总被引:1,自引:0,他引:1
Yeast high stable plasmid vector pHC11 was constructed by introducing pEMBL Yi27 cleaved with SmaI into the SnaBI site of intact 2 μm plasmid. The result of plasmid stability assay revealed that 82% of the host cells still harbored the vector after 50-generations growth in non-selective medium, which confirmed the existence of a non-functional region in 2 μm plasmid. The human interferon αA (IFN αA) gene expression-secretion cassette was inserted into pHC11, and the yeast transformant was cultured in complex medium. Tbe data showed that the expressed product was 36.8% of the total protein amount in the culture supernatant and the IFN αA biological activity was 2.6×10~(10) units per liter, demonstrating that high-level expression and secretion of IFN αA were achieved in yeast by using the stable vector pHC11. 相似文献
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We investigate the dynamics of parity-and time-reversal(PT) symmetric two-energy-level atoms in the presence of two optical and one radio-frequency fields. The strength and relative phase of fields can drive the system from the unbroken to the broken PT symmetric regions. Compared with the Hermitian model, Rabi-type oscillation is still observed, and the oscillation characteristics are also adjusted by the strength and relative phase in the region of the unbroken symmetry. At the exception point, the oscillation breaks down. To better understand the underlying properties we study the effective Bloch dynamics and find that the emergence of the PT components of the fixed points is the feature of the PT symmetry breaking and the projections in the x–y plane can be controlled with high flexibility compared with the standard two-level system with the PT symmetry. It helps to study the dynamic behavior of the complex PT symmetric model. 相似文献