微波消解–电感耦合等离子体原子发射光谱法同时测定儿童唇膏产品中19种有害元素

建立微波消解–电感耦合等离子体原子发射光谱法同时测定儿童唇膏产品中硼、铝、钛、铬、锰、钴、镍、铜、锌、砷、硒、锶、镉、锡、锑、钡、汞、铅和铋等19种有害元素。取样量为0.5 g时,硝酸用量为5.0 mL,过氧化氢溶液(质量分数为30%)用量为2.0 mL,采用微波消解法处理样品。优化的电感耦合等离子体原子发射光谱仪工作条件：射频功率为1.20 kW;等离子体气流量为12.00 L/min;雾化气流量为0.70 L/min;辅助气流量为1.00 L/min;蠕动泵转速为12 r/min (分析)和80 r/min (清洗)。19种元素的质量浓度在0.10～5.00 mg/L范围内与其对应的信号强度成良好线性关系,相关系数均大于0.999,检出限为0.12～22.80 μg/L,加标回收率为80.9%～96.4%,测定结果的相对标准偏差为0.38%～4.89%(n=6)。     

Neural Signal Tuned by Random Long-range Connections in Coupled FitzHugh-Nagumo Neurons Systems

We investigate the effect of random long-range connections on signal propagation in an array of coupled FitzHugh- Nagumo （FHN） neurons. The neural network can be obtained by randomly adding a small fraction of shortcuts in an originally locally coupled one-dimensional chain. It is shown that when the first neuron is subjected to external stimuli, it fires and excites its connected neighbours, such that the neural signal may propagate along the chain favoured by the shortcuts. Moreover, there exists an optimal number of shortcuts which can lead to the most synchronous behaviour. In addition, how the region of the fraction of shortcuts varies with the coupling strength is also discussed. These results suggest that topological disorder in the neural network may play a vital role in helping information processing in living systems.     

Manipulating Single-Photon Transport Properties in an Asymmetrical Waveguide Coupled to a Whispering-Gallery Resonator Containing a Two-Level Atom

A hybrid system containing an asymmetrical waveguide coupled to a whispering-gallery resonator embedded with a two-level atom is designed to investigate single-photon transport properties. The transmission and reflection amplitudes are obtained via the discrete coordinates approach. Numerical simula, tion demonstrates that a tri- frequency photon attenuator is realized by controlling the couplings between the asymmetrical waveguide and the whispering-gallery resonator. The phase shift, group delay and dissipation effects of the transmitted single-photon are also discussed.     

藏药珠西的化学成分与结构分析

采用X射线荧光(XRF)、电感耦合等离子体发射光谱(ICP-OES)和X射线衍射(XRD)对不同来源藏药珠西中的元素成分和结构组成进行测定,以期揭示其药理作用的物质基础。XRF和ICP-OES分析结果表明,藏药珠西中主要元素为Fe,S和O,及少量的Si,Na,Mg,Al,K,Ni,Ca,Ti等元素。XRD分析表明,藏药珠西中主要存在立方晶系FeS2,此外还含有少量的斜方晶系Fe+3O(OH)等。通过XRF,ICP-OES和XRD分析,获得了藏药珠西的化学成分和结构组成基本数据,为其药理作用物质基础的揭示和质量标准的制定提供了科学依据。     

蜂窝密封内耦合传热特性的研究

采用耦合传热数值计算方法,研究了典型航空发动机阶状蜂窝密封内的传热特性,并利用实验数据对数值方法的正确性进行了考核。计算得到的转子面和静子面上换热系数分布与实验值吻合良好。通过对比5种不同的两方程涡黏湍流模型,结果表明:k-ω湍流模型和SST湍流模型在高温度梯度区域对换热系数分布的求解具有较高的精度,明显优于标准k-ε和k-εRNG湍流模型。与光滑面迷宫密封相比,蜂窝芯格结构对转子面上平均换热系数影响较小,但大幅减小了密封静子面上的换热能力;蜂窝芯格结构使得齿尖温度梯度略微增大,但明显使得静子固体区域的温度梯度减小。     

Sixth harmonic generation of 1064-nm laser in KBBF prism coupling devices under two kinds of gas conditions

The conversion efficiency on the sixth harmonic of 1064 nm in KBe2BO3F2 （KBBF） at different gas pressures in two kinds of gases, helium and nitrogen, is measured and compared. In the both gases, maximum conversion efficiency on the sixth harmonic of 1064 nm in high vacuum is nearly 10% of 355 nm, which is almost four times higher than that in low vacuum. The maximum average output power at 177.3 nm is 670 ttW with the repetition rate of 10 Hz and the duration of 20 ps in high vacuum. It indicates that the sixth harmonic generation in high vacuum is more preferable than that in low vacuum.     

Spin-Dependent Electron Properties of a Triple-Terminal Quantum Dot Structure

Electron transport properties of a triple-terminal Aharonov-Bohm interferometer are theoretically studied. By applying a Rashba spin-orbit coupling to a quantum dot locally, we find that remarkable spin polarization comes about in the electron transport process with tuning the structure parameters, i.e., the magnetic flux or quantum dot levels. When the quantum dot levels are aligned with the Fermi level, there only appear spin polarization in this structure by the presence of an appropriate magnetic flux. However, in absence of magnetic flux spin polarization and spin separation can be simultaneously realized with the adjustment of quantum dot levels, namely, an incident electron from one terminal can select a specific terminal to depart from the quantum dots according to its spin state.