High entanglement generation and high fidelity quantum state transfer in a non-Markovian environment

This paper analyses a system of two independent qubits off-resonantly coupled to a common non-Markovian reservoir at zero temperature. Compared with the results in Markovian reservoirs, we find that much higher values of entanglement can be obtained for an initially factorized state of the two-qubit system. The maximal value of the entanglement increases as the detuning grows. Moreover, the entanglement induced by non-Markovian environments is more robust against the asymmetrical couplings between the two qubits and the reservoir. Based on this system, we also show that quantum state transfer can be implemented for arbitrary input states with high fidelity in the non-Markovian regime rather than the Markovian case in which only some particular input states can be successfully transferred.     

基于微拉曼光谱技术的氧化介孔硅热导率研究

利用基于有效介质理论的介孔硅传热机理,提出一个用于分析氧化介孔硅热导率的理论模型,对影响氧化介孔硅有效热导率的因素进行了理论分析,得出用于计算氧化介孔硅有效热导率的计算公式. 采用双槽电化学腐蚀法制备介孔硅,利用微拉曼光谱技术研究了氧化介孔硅热导率随所制备介孔硅孔隙率的变化规律,比较了经不同温度处理的氧化介孔硅的导热性能差异. 孔隙率为60%,73.4%和78.8%的所制备介孔硅经300℃氧化处理后,其热导率值为8.625W/(m·K),3.846W/(m·K)和1.817W/(m·K);孔隙率为73.4 关键词： 理论模型 氧化介孔硅 微拉曼光谱 有效热导率     

Synchronization of stochastically hybrid coupled neural networks with coupling discrete and distributed time-varying delays

A general model of linearly stochastically coupled identical connected neural networks with hybrid coupling is proposed, which is composed of constant coupling, coupling discrete time-varying delay and coupling distributed timevarying delay. All the coupling terms are subjected to stochastic disturbances described in terms of Brownian motion, which reflects a more realistic dynamical behaviour of coupled systems in practice. Based on a simple adaptive feedback controller and stochastic stability theory, several sufficient criteria are presented to ensure the synchronization of linearly stochastically coupled complex networks with coupling mixed time-varying delays. Finally, numerical simulations illustrated by scale-free complex networks verify the effectiveness of the proposed controllers.     

Elastic behaviour of an edge dislocation near a sharp crack emanating from a semi-elliptical blunt crack

The interaction between an edge dislocation and a crack emanating from a semi-elliptic hole is dealt with. Utilizing the complex variable method, closed form solutions are derived for complex potentials and stress fields. The stress intensity factor at the tip of the crack and the image force acting on the edge dislocation are also calculated. The influence of the morphology of the blunt crack and the position of the edge dislocation on the shielding effect to the crack and the image force is examined in detail. The results indicate that the shielding or anti-shielding effect to the stress intensity factor increases acutely when the dislocation approaches the tip of the crack. The effect of the morphology of the blunt crack on the stress intensity factor of the crack and the image force is very significant.     

有界随机噪声激励下软弹簧Duffing振子的安全盆分叉

研究了软弹簧Duffing振子在有界随机噪声激励下，系统安全盆的侵蚀现象，并提出了随机安全盆分叉的概念. 计算表明，由于随机扰动的影响，系统的随机安全盆分叉点发生了偏移. 关键词： Duffing振子 有界随机噪声 安全盆 分叉     

不同结构六边形斑图演化过程光谱特性

采用发射光谱法,研究了水电极介质阻挡放电中具有相同对称性的3种不同结构的六边形斑图演化过程的光谱特性。实验结果表明,随着外加电压的增加,放电首先形成六边形点阵斑图,然后是空心六边形斑图,最后是蜂窝六边形斑图。利用氩原子696.5 nm(2P_2→1S_5)谱线的展宽、氩原子763.2 nm(2P_6→1S_5)与772.1 nm(2P_2→1S_3)两条谱线强度比法和氮分子第二正带系(C~3Π_u→B~3Π_g)的发射谱线,研究上述3种斑图的电子密度、电子激发温度及分子振动温度。结果发现,随着外加电压的升高,六边形点阵斑图、空心六边形斑图和蜂窝六边形斑图的电子密度逐渐减小,而电子激发温度和分子振动温度逐渐增加。等离子体状态的改变直接影响着斑图的自组织。     

Impact on the magnetic compressor due to CSR

When an electron bunch is compressed in a chicane compressor, the CSR (coherent synchrotron radiation) will induce energy redistribution along the bunch. Such energy redistribution will affect the longitudinal emittance as a direct consequence. It will also excite betatron oscillation due to the chromatic transfer functions, and hence a transverse emittance change. So, it is indispensable for us to find a way to alleviate the CSR-caused emittance dilution and the bad result of chicane compressor in PKU-FEL.     

矿物中药钟乳石的X射线衍射Fourier指纹图谱

研究矿物中药钟乳石X射线衍射Fourier指纹图谱.对10批主产地的钟乳石药材X射线衍射Fourier图谱进行分析,建立钟乳石X射线衍射Fourier指纹图谱,并通过相似度计算,区分钟乳石、其他含钙矿物中药、同种化学试剂CaCO3.主成分相同的矿物中药利用X射线衍射Fourier指纹图谱无法完全区分,但钟乳石与同种化学试剂CaCO3的X射线衍射Fourier图谱区别显著.利用X射线衍射Fourier指纹图谱可以很好的区分含有不同化学成分的矿物药,而对于主成分相同的矿物中药,就不能简单地利用它们的X射线衍射Fourier指纹图谱加以区分,即X射线衍射Fourier指纹图谱仅具有相对的专属性.     

Ge在Ru(0001)表面上生长及其性质研究

报道Ge在Ru(0001)表面上生长以及相互作用行为的扫描隧道显微镜（STM）和x射线光电子能谱（XPS）研究. STM的实验结果表明Ge在Ru(0001)表面的生长呈典型的Stranski_Krastanov生长模式，Ge的覆盖度小于单原子层时呈层状生长，而从第二层开始呈岛状生长. XPS测量显示衬底Ru(0001)与Ge的相互作用很弱. Ru(0001)表面的Ru 3d5/2和Ru 3d3/2芯态结合能分别处于2798和2840 eV. 随着Ge的生长，到Ge层的厚度为20个单原子层，衬底Ru 3d芯态结合能减小了约02 eV，而Ge 3d芯态结合能从Ge低覆盖度时的289 eV增加到了290 eV，其相对位移约为01 eV. 关键词： Ge Ru表面 生长 相互作用     

双路光谱展宽的钛宝石飞秒光学频率梳系统

对中国计量科学研究院研制的第一代基于钛宝石飞秒激光器的光学频率梳系统进行了改进和优化. 通过对激光器重复频率、光谱展宽以及拍频信号探测等方面的改进,有效地降低了光谱展宽的复杂性,提高了飞秒光学频率梳系统的稳定性和激光频率测量的便捷性. 采用该光学频率梳系统对碘稳频532 nm和碘稳频633 nm激光绝对频率进行了测量,测量结果在国际推荐值的不确定度范围之内. 关键词： 光学频率计量 飞秒光学频率梳 光谱展宽