Simultaneous determination of cinnamaldehyde and its metabolite in rat tissues by gas chromatography–mass spectrometry

Cinnamaldehyde (CA), an active ingredient isolated from the traditional Chinese medicine Cortex Cinnamomi, has a wide range of bioactivities. To clarify the distribution characteristics of CA, a selective and sensitive method utilizing gas chromatography–mass spetrometry was initially developed for simultaneously determining the concentration of CA and its metabolite cinnamyl alcohol in rat tissues. Selected ion masses of m/z 131, 105 and 92 were chosen, and separation of the analytes was performed on a DB‐5 ms (30 m × 0.25 mm, 0.25 µm, thickness) capillary column by gas chromatography–mass spectrometry. The calibration curves demonstrated good linearity and reproducibility over the range of 20–2000 and 20–4000 ng/mL for various tissue samples. Recoveries ranged from 86.8 to 107.5%, while intra‐ and interday relative standard deviations were all <11.3%. The analysis method was successfully applied in tissue distribution studies for CA and cinnamyl alcohol. As CA and cinnamyl alcohol may inter‐convert to one another, simultaneous determination of both analytes provides a comparative and accurate data for tissue study. The concentrations of CA and cinnamyl alcohol remaining in spleen were the highest among the main organs, including heart, liver, spleen, lung, kidney and brain. In addition, there was no long‐term accumulation of CA in rat tissues. Copyright © 2014 John Wiley & Sons, Ltd.     

Optical fiber acoustic sensing multiplexing system based on TDM/SFDM

We propose a system of time-division multiplexing(TDM) and spatial frequency-division multiplexing(SFDM). Extrinsic Fabry–Perot interferometric sensors are applied to detect weak acoustic signals. The broadband source is employed, the light from it is modulated by a pulse signal sequence and is efficiently amplified by semiconductor optical amplifiers. Experimental results show that the equivalent noise pressure spectrum level is-97.2 d B re 1 rad/√Hz below 1250 Hz, and the cross talk between two sensors in one TDM channel is-32.7 d B with a cavity length difference of 60 μm. The number of sensors in this multiplexing system can theoretically reach 160.     

TBOR-shaped electro-optic modulator with dual output based on double-layer graphene

We proposed an electro-optic modulator with two-bus one-ring (TBOR) structure to improve the extinction ratio and reduce insert loss. It has a dual output compared with one-bus one-ring structure. In addition, double-layer graphene makes it possible for the modulation in the visible to mid-infrared wavelength range. It shows that this new electro-optic modulator can present two switching states well with low insertion loss, high absorption and high extinction ratio. At $\lambda =1550\text{ nm}$, when the switching states are based on the chemical potential, ${\mu }_{\mathrm{c}}=0.38\text{ eV}$ and ${\mu }_{\mathrm{c}}=0.4\text{ eV}$, the insertion losses of both output ports are less than 2 dB, the absorption of the output port coupled via a micro-ring reaches 45 dB and the extinction ratio reaches 14 dB. When the refractive index of the dielectric material is 4.2, the applied voltage will be less than 1.2 V, thus can be used in low-voltage CMOS technology.     

Densification involved in the UV-based photosensitivity of silicaglasses and optical fibers

A comprehensive survey of photosensitivity in silica glasses and optical fiber is reviewed. Recent work on understanding the mechanisms contributing to germanium or aluminum doped fiber photosensitivity is discussed within the framework of photoelastic densification models     

铁分子Fe2的自旋极化效应

采用密度泛函方法(B3P86)对 Fe_2分子结构进行了优化.计算结果中未观察到自旋污染,基态波函数与高态波函数并未混杂,结果表明,Fe_2中有8个未配对电子,这些电子空间分布不同和自旋平行产生的自旋极化效应,使 Fe_2能量最低.计算结果表明,Fe_2分子的基态是~9∑_g~ ,并非~7Δ_u,进而表明 Fe_2的自旋平行效应比电子自旋配对效应要强.计算得到该分子基态的二阶、三阶和四阶力常数分别为1.4115×10~(-2)aJ/nm~2、-37.1751×10~3aJ/nm~3和 98.7596×10~4aJ/nm~4；光谱数据ω_eχ_e、B_e、α_e分别为0.3522、0.0345、 0.4963×10~(-4)cm~(-1)；离解能为3.5522eV,平衡键长为0.2137nm,振动频率为292.914cm~(-1)；并得到了 Murrel-Sorbie 函数.     

A comparison between different PMD compensation techniques

We quantify the benefits of using different techniques for compensation of polarization mode dispersion (PMD) in fiber-optic communication systems by means of numerical simulations. This is done both with respect to PMD-induced pulse broadening and in terms of system outage probability for different data formats [nonreturn-to-zero (NRZ) and return-to-zero (RZ)]. Attention is focused on simple and relevant single- and double-stage post-transmission compensators with a few degrees of freedom (DOF). It is generally believed that a PMD compensator with a polarization controller and a variable delay line can only compensate the PMD to the first order. We show, from analytical results, the counterintuitive fact that this scheme can also partially compensate for higher order PMD. We also investigate the benefit of using a polarizer as compensation element where the optical average power can be used as a feedback signal     

利用框架理论对信号进行重建

在Hilbert空间中讨论了框架的一些重要的性质,定义了一个框架算子,并讨论了该算子的性质。根据实际问题构造了一框架,使信号在此框架下的投影正好为非均匀采样值。给出了一种框架界的估计方法和重建原信号的迭代算法,最后,用仿真验证了此算法的有效性。     

Investigation of Mechanical and Electrical Characteristics for Cracked Conductive Particle in Anisotropic Conductive Adhesive (ACA) Assembly

In an anisotropic conductive adhesive (ACA) assembly, the electrical conduction is usually achieved with the conductive particles between the bumps of integrated circuit (IC) and corresponding conductive tracks on the glass substrate. Fully understanding of the mechanical and electrical characteristics of ACA particles can help to optimize the assembly process and improve the reliability of ACA interconnection. Most conductive particles used in the ACA assembly are with cracks in the metal coating of the particles after the ACA bonding. This paper introduced the fracture analysis by applying the cohesive elements in the numerical model of the nickel-coated polymer particle and further simulating the cracks initiation and propagation in the nickel coating during the ACA bonding. The simulation results showed that the stress distribution on the nickel-coated particle with cracks was significantly different from that on the nickel-coated particle without crack, indicating that the stress analysis by taking the crack into consideration is very important for the reliability assessment of the ACA interconnection. The stress analysis of cohesive elements indicated that the cracks initiated at the central area of the nickel coating and propagated to the polar area. Furthermore, by the introduction of a new parameter of the virtual resistance, a mathematical model was established to describe the electrical characteristics of the nickel-coated particle with cracks. The particle resistance of the nickel-coated particle with cracks was found to be much higher than that of the particle without crack in the optimized bonding pressure range, indicating that it is necessary to take the crack into consideration for the particle conduction analysis as well. Therefore, the fracture analysis on the conductive particle by taking the crack into consideration could accurately evaluate the reliability of ACA interconnection and avoid serious reliability issues.