Synthesis and self-assembly of side-chain azocomplex for preparation of solid and hollow nanosphere

A new strategy based on ionic self-assembly technology was provided for design of solid and hollow nanospheres. Solid azocomplex nanospheres were constructed by ionic self-assembly of statistical ionomer and metanil yellow. The structure of azocomplex and self-assembly behaviors were examined by a variety of techniques including ¹H-NMR, ¹³C-NMR, DSC, FTIR, UV–vis, TEM, and elemental analysis. The azocomplex was subjected to solvent-induced self-assembly to construct a variety of morphologies. Solid polymeric nanospheres with the sizes of 50~100?nm in diameter were formed in aqueous solution. High-resolution transmission electron microscopes and X-ray energy dispersion spectrometer were used to study the morphology and composition of the solid nanospheres. The spherical and ordered structure was destroyed in DMF, and converted into membrane structure. Polymeric hollow nanospheres with azobenzene chromophores were formed in DMF/H₂O mixed solvent, with 62.5% H₂O in mass. The size of these hollow nanospheres was 50~120?nm in diameter.     

Mild ketone formation via Ni-catalyzed reductive coupling of unactivated alkyl halides with acid anhydrides

Ni-catalyzed ketone formation through mild reductive coupling of a diverse set of unactivated alkyl bromides and iodides with particularly aryl acid anhydrides was successfully developed using zinc as the terminal reductant. These conditions also allow direct coupling of alkyl iodides with aryl acids in the presence of Boc(2)O and MgCl(2).     

离子交换纤维的红外光谱研究

合成了离子交换纤维交研究了它们的红外光谱，得到了一些有价值的结果。     

Design of multi-channel optical code-division multiple-access encoders and decoders based on sampled fiber Bragg gratings

An encoding/decoding scheme of multi-channel optical code-division multiple-access (OCDMA) system using sampled fiber Bragg gratings (SFBGs) is proposed and numerically investigated. A multiple-phase-shift (MPS) technique based SFBG is first developed as a dense wavelength-division multiplexing (DWDM) device to accommodated multiple channels. The OCDMA scheme is achieved through phase coding/encoding on each individual channel of the SFBG and the auto correlative ratio for each user is larger than 14.3 dB. The whole system exhibits enhanced performance in terms of the capacity and security since the OCDMA technique is simultaneously implemented for all channels using the single SFBG.     

Influence of polarization mode competition on chaotic unpredictability of vertical-cavity surface-emitting lasers with polarization-rotated optical feedback

The chaotic unpredictability of vertical-cavity surface-emitting lasers (VCSELs) with polarization-rotated optical feedback is evaluated quantitatively via the normalized permutation entropy H. The effect of polarization mode competition (PMC) is explored. For weak PMC, the H for X-polarization mode, Y-polarization mode, and total output are close to each other, while for strong PMC, the H for the total output is the highest one, which indicates that the permutation entropy is an effective tool for quantifying chaotic unpredictability of VCSELs and provides valuable information for choosing the proper chaotic carrier.     

Accurate characterization of complex pulses by delay-controlled fringe-free interferometry of spectral high-resolution technique

We discuss the disadvantage in conventional Spectral Phase Interferometry for Direct Electric-field Reconstruction (SPIDER) technology in complex femtosecond pulse measurement. An improved version of conventional technology named DC-FISH is presented, where single replica of the unknown pulse upconverts synchronously with two frequency-shifted narrow-banded long pulses. The spectral phase of the unknown pulse can be directly calculated from the fringe-free spectra with the introduction of a suitable small delay between the upconverted pulses. The numerical simulation results are achieved to identify a higher efficiency and lower requirements on measurement in novel approach.     

Design of polarization-maintaining retro-reflector for folded-path applications

A design of polarization-maintaining retro-reflectors(PMRRs) for folded-path applications is proposed and analyzed.The prism-based scheme enables the output light,which is parallel to the input,to have an identical state of polarization.The principle of the design is theoretically verified,and the related error is analyzed due to possible manufacturing imperfection.The maximum spatial angle error is ±2.75°.The effect on the extinction ratio and insertion loss is also discussed,which further proves the design’s feasibility in practical applications.     

Controllable phase transitions and novel selection rules in Josephson junctions with inherent orthogonality

We propose a new type of Josephson junction consisting of topologically nontrivial superconductors with inherent orthogonality and a ferromagnetic interface. It is found this type of junction can host rich ground states: 0 phase, π phase, $0+\pi$ phase, ${\phi }_0$ phase and ${\phi }_0\pm \phi$ phase. Phase transitions can be controlled by changing the direction of the interfacial magnetization. Phase diagrams are presented in the orientation space. Novel selection rules for the lowest order current, $\sin ??$ or $\cos ??$, of this kind of junction are derived. General conditions for the formation of various ground states are established, which possess guiding significance to the experimental design of required ground states for practical applications. We construct the succinct form of a Ginzburg–Landau type of free energy from the viewpoint of the interplay between topological superconductivity and ferromagnetism, which can immediately lead to the selection rules. The constructed terms are universally available to the topological Josephson junctions with or without inherent orthogonality reported recently. The spin supercurrent, its selection rules and their relations to the constructed energy are also investigated.     

裂解气相色谱-质谱法分离鉴定聚氨酯防水涂料中的煤焦油

建立了采用闪蒸裂解气相色谱-质谱测定固化后的聚氨酯防水涂料中的煤焦油的新方法。该方法方便快捷,无需对样品进行前处理,而且测定结果不受聚氨酯组分的干扰。该方法在建筑材料中有毒有害组分的分析检测方面有一定的应用价值。     

Characterization of surface interaction of inorganic fillers with silane coupling agents

Coupling agent (CA) can not only help filler achieve better dispersion in polymer matrix, but also improve the roughness of the composite with good rigidity at the same time. In this paper, the interaction of silane coupling agents with inorganic fillers (in our case are Mg(OH)₂ and CaCO₃) were studied by pyrolysis gas chromatography (PGC), as well as Fourier transform infrared spectroscopy. By two-step pyrolysis (first at 250 °C, then at 600 °C), physisorbed and chemisorbed silane on fillers can be distinguished. The bonded silane cannot be flash vaporized at 250 °C, it results in new peaks different from that of silane in pyrograms at 600 °C. The chemisorbed amount of silane increases with time and temperature and finally reaches a plateau. The result showed that PGC was an effective analytical tool to prove the existence of interaction between inorganic filler and CA.