Demonstration of an optical self-clocked time-division switch

A novel architecture for an optical time-division switch is investigated and demonstrated at a bit rate of 625 Mbit/s. The self-clocked configuration eliminates some of the limitations found in previous optical implementations of time-division switches: the switch operation is asynchronous, no read gate is required, and an optimal number of delay lines is used. Furthermore, this paper reports the first experimental demonstration of optical space-sorting demultiplexing.     

借助液体透射电镜原位分析钯纳米棒的可控性氧化刻蚀

借助原位液体透射电镜,我们观察并研究了钯纳米棒溶液环境下的氧化刻蚀的微观行为及机理。通过改变钯纳米棒所处的液体环境,有效地控制了钯纳米棒的氧化刻蚀行为。由于端部具有较高的反应活性,钯纳米棒在氯化铁溶液中的氧化刻蚀会选择沿着轴向进行,具有明显的各向异性。当反应在超薄液层进行时,钯纳米棒的氧化刻蚀会变为准各向同性。这种行为是由于超薄溶液中溶解产物以及氧化物的扩散被抑制,在纳米棒端部选择性发生的氧化刻蚀会受到阻碍。最后,我们发现在钯纳米棒端部选择性沉积金,可以保护纳米棒的端部不受氧化,从而能控制刻蚀沿着钯纳米棒的径向进行。本文的研究结果对贵金属纳米晶的结构参数的精确调控以利于实际应用具有重要的意义。     

Electrochemical Determination of Sunscreens Agents in Cosmetic Using Square Wave Voltammetry

Sunscreen agents and in particular UV filters are compounds added in different cosmetic formulations, that has the function of preventing damage caused by sun exposition. Therefore, this paper proposes the development of a simple, fast and reliable electroanalytical method utilizing square wave voltammetry (SWV) to the determination of Benzophenone‐3 (BZ‐3), camphor 4‐methylbenzylidene (MBC) and 2‐ethylhexyl‐4‐methoxycinnamate (OMC) in cosmetic samples. The electrochemical system consisted of a cell with three electrodes: work – gold electrode modified, reference – Ag/AgCl_(sat) and auxiliary – platinum, using as supporting electrolyte 4.0 mL of Britton Robinson Buffer 0.04 mol L^?1 (pH=4.0), 1.0 mL of methanol and 5.50×10^?4 mol L^?1 of cetyltrimethylammonium bromide (CTAB). The method was validated using three commercial sunscreen samples and the results showed recovery values between 83 and 98 %. The average values found for the analysed samples were 3.49 % m/m (728 mg L^?1) to BZ‐3, 0.56 % m/m (113 mg L^?1) to MBC and 0.99 % m/m (208 mg L^?1) to OMC. The detection (DL) and quantification (QL) limits were 0.47 mg L^?1 and 1.56 mg L^?1 to BZ‐3, 0.77 mg L^?1 and 2.58 mg L^?1 to MBC and 0.78 mg L^?1 and 2.59 mg L^?1 to OMC, respectively. The sunscreen protector samples were also evaluated by high‐performance liquid chromatography (HPLC) demonstrating a good correlation between the results and compared the results with allowed concentration.     

“多才多艺”的铁元素*

铁在自然界中含量丰富,化学性质活泼,能够形成多种应用广泛的物质及材料,富有发展潜力。简述了铁元素的发现与性质,并重点介绍了铁的功能与应用。其中铁的应用主要围绕铁及其化合物在医学治疗、能源材料和环境保护领域所发挥的重要作用进行了阐述。     

Organosulfonate Counteranions—A Trapped Coordination Polymer as a High-Output Triboelectric Nanogenerator Material for Self-Powered Anticorrosion

Selection of the friction electrode materials is crucial to the performance of a triboelectric nanogenerator (TENG). In the present study, a metal–organic coordination complex containing organosulfonate counteranions with electron-donating ability was synthesized through the coordination-driven self-assembly approach under mild reaction conditions and was chosen as a positive electrode material to construct a triboelectric nanogenerator, exhibiting high-output performance with a peak value of short circuit current density of 98.6 μA and an output voltage of 1180 V. As a practical application, it was shown to light up 1488 commercial green LEDs and power an anticorrosion system device to protect metals from corrosion.     

Synthesis of 3-hetarylpyrroles by Suzuki–Miyaura cross-coupling

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A method of segment protection based on p-cycle for dynamic multicast with limited-range wavelength converter in WDM network

In the optical multicast network, node and link failures have very important influence on the network survivability which may lead to multiple destinations cannot receive data. Based on the wavelength layered-graph method, a method of efficiency-score based on heuristic algorithm of pre-configured cycle (p-Cycle) based-segment protection (ESHS) for dynamic multicast with limited-range wavelength conversion was presented in this paper. By finding the multicast tree segment protection, the total available p-Cycles are constructed for the multicast. Then we calculate each p-Cycle efficiency-score, the highest efficient-score p-Cycle is selected as the multicast route protection p-Cycle. The simulation results show that the ESHS can get higher performance than the existing ESHT algorithm, in terms of multicast request blocking probability and wavelength utilization.     

A mild and efficient THP protection of indazoles and benzyl alcohols in water

A mild and efficient method for THP protection of indazoles and benzyl alcohols has been developed in water, the most environmentally friendly solvent, in which Tween 20 (2% w/w) was added to form aqueous micelles to increase the solubility of starting materials. This aqueous protocol allowed the reaction to proceed smoothly at room temperature and with only 1.2 equiv of DHP, providing moderate to good yields of THP protected products for a wide scope of substrates. In addition, the methodology was highly practical in the large-scale synthesis (1?g synthesis of 2c as an example), wherein the convenient work-up and purification procedure (simple filtration) made the protocol even more attractive.     

Structural Selection in G‐Quartet‐Based Hydrogels and Controlled Release of Bioactive Molecules

A guanosine‐5′‐hydrazide can entrap biologically interesting molecules such as acyclovir, vitamin C, and vancomycin into its hydrogel network. Controlled release of these molecules was monitored by ¹H NMR spectroscopy. The hydrazide may potentially form mixed G–G quartets with analogous compounds containing a guanine group. ¹H NMR spectroscopy was used to study the inclusion of various guanine derivatives into the hydrogel. The structural selectivity was found to depend strongly on both the shape and the charge of the additive and may arise from the strong cohesion of the supramolecular architecture of the gel and the resulting resistance to perturbation by foreign bodies. Hydrogels thus offer a promising medium for highly selective, controlled release of bioactive substances.