Electrons are transported through phenylene-ethynylene oligomer monolayers via localized molecular orbitals

We report excellent correlations between the first negative threshold potentials (V(TH)s) for electric conduction, electrochemical potentials, and computed lowest unoccupied molecular orbital energies in a series of phenylene-ethynylene oligomers bearing a sulfur-based anchoring unit and different electroactive substituents on the central benzene ring. The theoretical and electrochemical results strongly suggest that the peaks observed in the i-V curves have a true molecular origin and are associated with distinct unoccupied molecular levels of the compounds that are strongly localized on the central ring (except for compound I). This localization might account for the existence of a long-lived radical-anion state that permits lateral electron hopping and leads to charge trapping and storage.     

Electro-optic Solc-type wavelength filter in periodically poled lithium niobate

We demonstrate an electro-optic Solc-type wavelength filter in periodically poled lithium niobate (PPLN). A Solc-type transmission spectrum is observed experimentally in PPLN with four periods from 20.2 to 20.8 microm. Modulation of the transmission power of the filter is realized by application of electric fields along the Y axis of the PPLN. It is observed that the wavelength can also be tuned by temperature.     

NanoCell electronic memories

NanoCells are disordered arrays of metallic islands that are interlinked with molecules between micrometer-sized metallic input/output leads. In the past, simulations had been conducted showing that the NanoCells may function as both memory and logic devices that are programmable postfabrication. Reported here is the first assembly of a NanoCell with disordered arrays of molecules and Au islands. The assembled NanoCells exhibit reproducible switching behavior and two types of memory effects at room temperature. The switch-type memory is characteristic of a destructive read, while the conductivity-type memory features a nondestructive read. Both types of memory effects are stable for more than a week at room temperature, and bit level ratios (0:1) of the conductivity-type memory have been observed to be as high as 10(4):1 and reaching 10(6):1 upon ozone treatment, which likely destroys extraneous leakage pathways. Both molecular electronic and nanofilamentary metal switching mechanisms have been considered, though the evidence points more strongly toward the latter. The approach here demonstrates the efficacy of a disordered nanoscale array for high-yielding switching and memory while mitigating the arduous task of nanoscale patterning.     

混合胶束对铟（Ⅲ）—邻氯苯基荧光酮显色反应的影响及其作用机理的研究

比较了８种非离子表面活性剂与ＣＴＭＡＢ形成的混合胶束对Ｉｎ（Ⅲ）－邻氯苯基荧光酮显色反应的作用，以ＣＴＭＡＢ－Ｔｗｅｅｎ８０的增敏效果最佳。研究了Ｉｎ（Ⅲ）－ｏ－Ｃｌ－ＰＦ－ＣＴＭＡＢ－Ｔｗｅｅｎ８０体系的形成条件及混合胶束的作用机理，以拟定的方法测定复杂试样中的铟，结果很满意。     

Surface ablation of lithium tantalate by femtosecond laser

We report measurements of the laser induced breakdown threshold in lithium tantalate with different number of pulses delivered from a chirped pulse amplification Ti: sapphire system. The threshold fluences were determined from the relation between the diameter D² of the ablated area and the laser fluence F₀. The threshold of lithium tantalite under single-shot is found to be 1.84 J/cm², and the avalanche rate was determined to be 1.01 cm²/J by calculation. We found that avalanche dominates the ablation process, while photoionization serves as a free electron provider.     

High modulus ratio shape‐memory polymers achieved by combining hydrogen bonding with controlled crosslinking

A new type of poly(methyl acrylate)‐co‐(acrylic acid) (PMA‐AA) networks obtained by combining hydrogen bonding with controlled crosslinking exhibit full and rapid shape‐memory recovery. The structure, thermal properties, dynamical mechanical properties and shape‐memory effects of these networks were presented. High modulus ratios were achieved for the series of PMA‐AA networks based on intense self‐complementary hydrogen bonding in poly(acrylic acid) (PAA) segments. This lead to excellent shape‐memory effects with strain‐recovery ratio above 99%. Meanwhile, faster recovery speed was achieved by the synergistic effect of hydrogen bonding and controlled crosslinking compared to the linear PMA‐AA copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1241–1245, 2011     

Multiwavelength fiber laser with fine adjustment, based on nonlinear polarization rotation and birefringence fiber filter

We have proposed and demonstrated a multiwavelength fiber laser based on nonlinear polarization rotation (NPR). The mechanism for stable room-temperature multiwavelength operation contributes to the ability of the intensity-dependent loss in NPR to effectively alleviate mode competition. In addition, through tuning the birefringence fiber filter, the lasing wavelength can be accurately tuned in the free spectrum range of the in-line periodic filter.     

Optimized Ship-Radiated Noise Feature Extraction Approaches Based on CEEMDAN and Slope Entropy

Slope entropy (Slopen) has been demonstrated to be an excellent approach to extracting ship-radiated noise signals (S-NSs) features by analyzing the complexity of the signals; however, its recognition ability is limited because it extracts the features of undecomposed S-NSs. To solve this problem, in this study, we combined complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) to explore the differences of Slopen between the intrinsic mode components (IMFs) of the S-NSs and proposed a single-IMF optimized feature extraction approach. Aiming to further enhance its performance, the optimized combination of dual-IMFs was selected, and a dual-IMF optimized feature extraction approach was also proposed. We conducted three experiments to demonstrate the effectiveness of CEEMDAN, Slopen, and the proposed approaches. The experimental and comparative results revealed both of the proposed single- and dual-IMF optimized feature extraction approaches based on Slopen and CEEMDAN to be more effective than the original ship signal-based and IMF-based feature extraction approaches.