离子束辅助沉积(IAD)镀制抗电磁干扰与减反射复合薄膜

在K9玻璃基底上将两种物理性能完全不同的薄膜形成组合膜系层,实现了抗电磁干扰、高透光的效果。技术指标为:在400nm-1100nm宽波段范围平均透光率不低于90%;为达到良好的抗电磁干扰屏蔽效果,抗电磁屏蔽其方块电阻值为4±0.5Ω/口。为满足设计技术指标要求,计算设计了抗电磁干扰与减反射复合膜系结构,进行了镀膜工艺实验。实验结果表明,通过采用离子束辅助沉积工艺技术,可改善光学薄膜的微观结构,进而提高了复合薄膜的光学、物理性能和膜层的稳定性。     

Fano-type resonances induced by a boson mode in Andreev conductance

We study spectroscopic signatures of a monochromatic boson mode interacting with a T-shape double quantum dot coupled between the metallic and superconducting leads.Focusing on a weak interdot coupling,we find that the proximity effect together with the bosonic mode are responsible for the series of Fano-type resonances appearing simultaneously at negative and positive energies.We investigate these interferometric features and discuss their influence on the subgap Andreev conductance taking into account the correlation effects driven by the Coulomb repulsion.     

迈克尔逊干涉仪测定金属线胀系数实验分析——升温测量和降温测量

利用迈克尔逊干涉仪可精确测量微小长度这一特性来测定金属在一定温度变化范围内,热胀冷缩的微小长度变化,从而得到一种更加精确测量金属线胀系数的新方法。并分别进行了升温测量和降温测量。后经对实验结果及实验误差的对比分析,结果显示,降温测量相比升温测量,可极大地减小实验误差,提高实验精度。     

Removal of spectral interferences and accuracy monitoring of trace cadmium in feeds by dynamic reaction cell inductively coupled plasma mass spectrometry

In the direct ICP-MS determination of Cd in feed samples, significant spectral interferences caused by high concentrations of Mo can play an important role. In the present study, Mo based oxide or hydroxide polyatomic interferences were eliminated by dynamic reaction cell (DRC) with O₂ as reaction gas. Some other oxide or hydroxide interferences (i.e. Zr and Ru) were simultaneously reduced by this technology. These potentially interfering polyatomic ions ⁹⁵Mo¹⁶O⁺, ⁹⁴Mo¹⁶OH⁺, ⁹⁴Zr¹⁶OH⁺, ⁹⁸Mo¹⁶O⁺, ⁹⁸Ru¹⁶O⁺ and ⁹⁷Mo¹⁶OH⁺ on ¹¹¹Cd⁺ and ¹¹⁴Cd⁺ were oxidized to higher oxides MoO₂⁺, MoO₃⁺, MoO₄⁺, RuO₃⁺, RuO₄⁺, MoO₂H⁺, MoO₃H⁺, ZrO₂H⁺ and ZrO₃H⁺. The rejection parameter q (RPq) of DRC and the flow rate of O₂ were optimized and set at 0.75 and 2.0 ml min^{− 1}, respectively. In addition, the residual isobaric interference of ¹¹⁴Sn on ¹¹⁴Cd was corrected using a mathematical correction equation. The limit of quantitation (LOQ) for ¹¹¹Cd or ¹¹⁴Cd was 0.8 or 1.0 ng g^{− 1} and the analysis results of NIST 1567a wheat flour and 1568a rice flour standard reference materials were in good agreement with the certified values. As the routine cadmium monitoring method in our laboratory, the proposed method was applied to the accuracy determination of 562 pig feed samples for the Monitoring of Central Meat Reserves (CMR) of China.     

Vortex-induced vibrations of two mechanically coupled circular cylinders with asymmetrical stiffness in side-by-side arrangements

Vortex-induced vibrations of two mechanically coupled circular cylinders with asymmetrical stiffness in side-by-side arrangements are numerically investigated in a uniform flow at a low Reynolds number of 100. The oscillation system is restricted to the cross-flow direction, giving rise to a coupled two-degree-of-freedom response. Attention is placed on the two cylinders with a center-to-center gap ratio of 4 and a mass ratio of 10. The flow dynamics are described by the two-dimensional incompressible Navier–Stokes equations and resolved by the Characteristic-Based-Split finite element method. The stiffness of the first spring that connects the lower cylinder to the wall is chosen such that the vortex-induced vibration of the associated single cylinder with the same stiffness undergoes a pre-synchronization (state A), synchronization (state B) and post-synchronization (state C), respectively. In each state, the stiffness of the second spring connecting the lower and upper cylinders is varied to cover both synchronization and de-synchronization regimes. Numerical results show that the mechanically coupled system locks on the first-mode natural frequency in state A, while on the second-mode natural frequency in states B and C. In such a lock-in regime, the amplitude ratios of the two oscillating and coupled cylinders collapse well onto the corresponding first or second free-vibration mode. The overall coupling mechanism is further explained in terms of the hydrodynamic coefficients, frequency characteristics, wake patterns and effective added mass, quantifying the associated fluid-structure interactions against those governing a single-degree-of-freedom, single-cylinder system.     

Cross-polarization properties of two Gaussian Schell-model beams through non-Kolmogorov turbulence

General expressions are derived for the spectral degree of cross-polarization (SDCP) of a beam generated by the superposition of two Gaussian Schell-model (GSM) beams, which illuminated with the same Gaussian Schell-mode source propagating in non-Kolmogorov turbulent atmosphere by adopting beam cross-spectral density matrix and Young's interference theory. In particular, through numerical examples based on our analytical formal the SDCP of two GSM beams is analyzed. Detailed analysis demonstrate that the SDCP is closely to the spacing of two beams on source plane as well as the strength of the atmospheric turbulent, but the fractal constant α has no affect on the SDCP.     

Crystallization and annealing effects of sputtered tin alloy films on electromagnetic interference shielding

Sn, Al and Cu not only possess electromagnetic interference (EMI) shield efficiency, but also have acceptable costs. In this study, sputtered Sn-Al thin films and Sn-Cu thin films were used to investigate the effect of the crystallization mechanism and film thickness on the electromagnetic interference (EMI) characteristics. The results show that Sn-xAl film increased the electromagnetic interference (EMI) shielding after annealing. For as-sputtered Sn-xCu films with higher Cu atomic concentration, the low frequency EMI shielding could not be improved. After annealing, the Sn-Cu thin film with lower Cu content possessed excellent EMI shielding at lower frequencies, but had an inverse tendency at higher frequencies. For both the Sn-xAl and Sn-xCu thin films after crystallization treatment, the sputtered films had higher electrical conductivity, however the EMI shielding was not enhanced significantly.     

Resonant regeneration in the sub-quantum regime – A demonstration of fractional quantum interference

Light shining through wall experiments (in the optical as well as in the microwave regime) are a powerful tool to search for light particles coupled very weakly to photons such as axions or extra hidden sector photons. Resonant regeneration, where a resonant cavity is employed to enhance the regeneration rate of photons, is one of the most promising techniques to improve the sensitivity of the next generation of experiments. However, doubts have been voiced if such methods work at very low regeneration rates where on average the cavity contains less than one photon. In this Letter we report on a demonstration experiment using a microwave cavity driven with extremely low power, to show that resonant amplification works also in this regime. In accordance with standard quantum mechanics this is a demonstration that interference also works at the level of less than one quantum. As an additional benefit this experiment shows that thermal photons inside the cavity cause no adverse effects.