基于搜索平均法的气象观测数据的非线性去噪

介绍了一种新型基于相空间重构和返回图法的非线性降噪方法——搜索平均法，首先将该方法应用于被高斯白噪声所污染的Henon映射时间序列，说明根据降噪理论所编写的计算程序的正确性；然后应用于中国气象局公布全国435站1960—2000年的逐日气温观测时间序列，并利用非线性预报方法衡量降噪的效果，验证了该方法的有效性.     

Fano effect of a parallel-coupled triple Rashba quantum dot system

Using the nonequilibrium Keldysh Green's function technique, the Fano effect of a parallel-coupled triple Rashba quantum dot system is investigated. The conductance as a function of electron energy is numerically calculated. Compared with the case of a parallel-coupled double quantum dot system, two additional Fano resonance peaks occur in the conductance spectrum. By adjusting the structural parameters, the two Fano resonance peaks may change into the resonance peaks. In addition, the influence of Rashba spin-orbit interaction on the conductance is studied.     

A realization of digital wireless transmission for MRI signals based on 802.11b

In this paper, a digital wireless transmission system based on 802.11b standard for magnetic resonance imaging (MRI) application is designed and built for the first time to eliminate the interference aroused by coil array cables. The analysis shows that the wireless receiver has a very high sensitivity to detect MRI signals. The modulation technique of differential quadrature phase shift keyed (DQPSK) can be applied to MRI data transmission with rate of 2 Mbps and bandwidth of 2 MHz. The bench test verifies that this wireless link has a dynamic range over 86 dB supporting up to 3 T MRI system data transmission. The 2D spin echo imaging of phantom is performed and the SNR of the image obtained by the wireless transmission can be comparable with that got by the coaxial cables.     

Fe3O4薄膜的电输运及光诱导特性研究

用脉冲激光沉积法在(111)Si衬底上成功制备了高度择优取向的Fe₃O₄薄膜.电阻-温度关系表明Fe₃O₄薄膜的Verwey转变(T_V)约在122 K,低温段(T_V)输运特征满足Mott变程跳跃模型,高温段(T>T_V)为小极化子输运.激光作用下的光电导实验发现,在整个温区表现为光致电阻率减小,而且低温段的电阻变化率比高温段要大很多.分析认为Fe₃O₄薄膜的光致电阻率变化主要与激光激发t_2g电子的转移有关. 关键词： 3O₄薄膜')" href="#">Fe₃O₄薄膜 小极化子 光诱导特性     

Critical behavior of XY spin chain with Dzyaloshinsky-Moriya interaction studied in terms of Loschmidt echo

In this paper, the critical behavior of the general XY spin chain with the Dzyaloshinsky-Moriya (DM) interaction is studied by means of a Loschmidt Echo (LE) calculation. LE presents a Gauss decay in the region of magnetic field intensity |λ|<1 and an exponential decay in the region of |λ|>1. There exists a critical spin chain size N_C. When spin chain size is larger than N_C, the value of λ corresponding to the minimum value of LE (λ_m) is independent of the spin chain size and keeps a stable value. In the region of λ<0, the stable value is same for different DM interactions. In the region of λ>0, the stable value varies with changing DM interaction.     

高能π–p碰撞J/ψ+γ硬衍射产生

用I–S模型与夸克偶素的色八重态产生机制,对πp碰撞J/ψ+γ协同产生的单衍射过程的微分截面及总截面进行计算,结果表明,把J/ψ+γ协同产生的单衍射过程和单举过程相结合,可以探测Pomeron中的胶子成分并对硬衍射因子化进行检验.     

有源消声耳罩中的通信信号补偿

在有源消声罩的很多应用场所,耳罩中引入了通信信号,在提高有源消声量的同时,还要保证通信信号的清晰。本文针对有源消声耳罩的不同消声结构,分析了其中通信信号所受到的影响,对于通信信号受影响较大的消声结构,提出了相应的补偿方案,推导了补偿器的理论补偿公式,并且实际设计了消声耳罩和相应的通信信号补偿器,实测了通信信号的补偿效果,就实验结果分析了通信信号补偿方案的有效性。     

与$\zeta(2k 1)$函数有关的两类快速收敛级数

Values of new series sum（（（2n-1）!ζ（2n））/（2n ＋ 2k）!）α2n from n=1 to ∞,sum（（（2n-1）!ζ（2n））/（2n＋2k ＋1）!）β2n from n=1 to ∞ are given concerning ζ（2k ＋ 1）,where k is a positive integer,α can be taken as 1,1/2,1/3,2/3,1/4,3/4,1/6,5/6 and β can be taken as 1,1/2.Some previous results are included as special cases in the present paper and new series converges more rapidly than those exsiting results for α = 1/3,or α = 1/4,or α = 1/6.     

Pt/Ti Electrodes of PZT Thin Films Patterning by Novel Lift-Off Using ZnO as a Sacrificial Layer

We achieve a successful novel lift-off of patterning Pt/Ti electrodes on SiO2/Si substrates by employing ZnO sacrificial layer deposition and patterning, successive uniform Pt/Ti deposition and final lift-off. Then we deposit PZT thin films on the electrodes. Compared with the conventional lift-off processes for the electrodes, this novel process does not need post-annealing, which must be performed after conventional lift-off process. It is demonstrated that the electrodes patterned by the novel lift-off process have stronger adhesion. The electrodes and the PZT films on the electrodes are more compact and smoother than those by the conventional lift-off process.     

Synthesis,crystal structures and DNA/human serum albumin binding of ternary Cu(II) complexes containing amino acids and 6‐(pyrazin‐2‐yl)‐1,3,5‐triazine‐2,4‐diamino

Two water‐soluble 6‐(pyrazin‐2‐yl)‐1,3,5‐triazine‐2,4‐diamino (pzta)‐based Cu(II) complexes, namely [Cu(l ‐Val)(pzta)(H₂O)]ClO₄ ( 1 ) and [Cu(l ‐Thr)(pzta)(H₂O)]ClO₄ ( 2 ) (l ‐Val: l ‐valinate; l ‐Thr: l ‐threoninate), were synthesized and characterized using elemental analyses, molar conductance measurements, spectroscopic methods and single‐crystal X‐ray diffraction. The results indicated that the molecular structures of the complexes are five‐coordinated and show a distorted square‐pyramidal geometry, in which the central copper ions are coordinated to N,N atoms of pzta and N,O atoms of amino acids. The interactions of the complexes with DNA were investigated using electronic absorption, competitive fluorescence titration, circular dichroism and viscosity measurements. These studies confirmed that the complexes bind to DNA through a groove binding mode with certain affinities (K_b = 4.71 × 10³ and 1.98 × 10³ M^?1 for 1 and 2 , respectively). The human serum albumin (HSA) binding properties of the complexes were also evaluated using fluorescence and synchronous fluorescence spectroscopies, indicating that the complexes could quench the intrinsic fluorescence of HSA in a static quenching process. The relevant thermodynamic parameters revealed the involvement of van der Waals forces and hydrogen bonds in the formation of complex–HSA systems. Finally, molecular docking technology was also used to further verify the interactions of the complexes with DNA/HSA.