Offline Arbitrated Quantum Blind Dual-Signature Protocol with Better Performance in Resisting Existential Forgery Attack

In this paper, we present an offline arbitrated quantum blind dual-signature protocol by using four-particle entangled Greenberger-Horne-Zeilinger(GHZ) states. By using the special relationship of four-particle GHZ states, we can not only support the security of quantum signature, but also guarantee the anonymity of the message owner. In our protocol, the authority of the arbitrator has been reduced, i.e., he will not help the receiver verify the signature in the verification. Compared with the previous quantum blind signature protocols, the presented arbitrator is offline. Finally, the security analysis and discussion are proposed.     

Hybrid Particle–Continuum Simulations of Polymer Brushes in Shear Flow

A hybrid particle–continuum method is used to study the shear flow confined between two opposing walls, one of which is coated with polymer chains. Molecular dynamics (MD) is used in the particle region near the brush and Navier–Stokes (NS) equations are applied in the remaining region where the continuum assumption holds. The information exchange from the continuum region to the particle region is implemented using the constrained particle dynamics. Both Couette shear flow and oscillatory flow are considered in the present work. The effect of the shear flow on the conformational characteristics of polymer brushes is analyzed. In the overlap region, the velocities obtained from MD simulations are smoothly connected with those from NS equations. Our investigations demonstrate that the hybrid particle–continuum model is valid in exploring the shear behavior of polymer brushes.     

Temperature/Light Dual‐Responsive Inclusion Complexes of α‐Cyclodextrins and Azobenzene‐Containing Polymers

Three kinds of photoresponsive copolymers with azobenzene side chains were synthesized by radical polymerization of N‐4‐phenylazophenylacrylamide (PAPA) with N‐isopropylacrylamide (NIPAM), N,N‐diethylacrylamide (DEAM) or N,N‐dimethylacrylamide (DMAM) respectively. Their structures were characterized by FT‐IR, ¹H‐NMR and UV/Vis spectroscopy. Their reversible photoresponses were studied with or without α‐cyclodextrin (α‐CD), which showed that both the copolymers and their inclusion complexes with α‐CD underwent rapid photoisomerization. The lower critical solution temperature (LCST) of the copolymers and their inclusion complexes with α‐CD were investigated by cloud point measurement, which showed that the LCST of three kinds of copolymers increased largely after adding α‐CD. After UV irradiation on the solutions of copolymers and their inclusion complexes, the LCST of the copolymers increased slightly with the absence of α‐CD, while decreased largely with the presence of α‐CD. Furthermore, the LCST reverted to its originality after visible light irradiation. This change of LCST could be reversibly controlled by UV and visible light irradiation alternately. In particular, in the copolymer of PAPA and DMAM, the reversible water solubility of the inclusion complexes could be triggered by alternating UV and visible light irradiation.     

Improved electrochemical performance of nano-crystalline Li2FeSiO4/C cathode material prepared by the optimization of sintering temperature

Li₂FeSiO₄/C cathode materials have been prepared using the conventional solid-state method by varying the sintering temperature (650 °C, 700 °C and 750 °C), and the structure and electrochemical performance of Li₂FeSiO₄/C materials are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge–discharge tests, respectively. The results show that Li₂FeSiO₄ nano-crystals with a diameter of about 6–8 nm are inbedded in the amorphous carbon, and the Li₂FeSiO₄/C material obtained at 700 °C exhibits an initial discharge capacity of 195 mA?h g^?1 at 1/16 C in the potential range of 1.5–4.8 V. The excellent electrochemical performance of Li₂FeSiO₄/C attributes to the improvement of conductivity and reduction of impurity by the optimization of the sintering temperature.     

Synthesis of oxazole and furan derivatives via Rh2(OAc)4-catalyzed C≡X bond insertion of cyclic 2-diazo-1,3-diketones with nitriles and arylacetylenes

Abstract

A convenient and efficient procedure for the synthesis of 2-substituted-6,7-dihydrobenzo[d]oxazol-4(5H)-ones and 2-aryl-6,7-dihydrobenzofuran-4(5H)-ones through a Rh₂(OAc)₄-catalyzed C≡X (X?=?N, C) insertion of cyclic 2-diazo-1,3-diketones with nitriles and aromatic alkynes has been developed. This reaction uses readily available starting materials and stable cyclic 2-diazo-1,3-diketone compounds, with desired products formed in good to high yields. A tentative mechanism involving a C≡X bond insertion and 1,5-dipolar electrocyclization/ring opening and cyclization sequence for this reaction is proposed.     

The (100) orientation evolution and temperature-dependent electrical properties of Bi(Zn1/2Ti1/2)O3–PbTiO3 ferroelectric films

The 0.2Bi(Zn_1/2Ti_1/2)O₃–0.8PbTiO₃ (0.2BZT–0.8PT) ferroelectric thin film was successfully fabricated on Pt(111)/Ti/SiO₂/Si substrates by a sol–gel method. The result indicates that the film exhibits the (100) preferred orientation and has a relatively dense and uniform microstructure with a thickness of ~230 nm. The formation mechanism of the oriented films was ascribed to the growth of the (100) oriented PbO layer at ~450 °C during a layer-by-layer crystallization process. Temperature-dependent electrical properties of the 0.2BZT–0.8PT films were investigated, showing that the film has a potential for high temperature applications.     

Bioconjugation of Proteins with a Paramagnetic NMR and Fluorescent Tag

Site‐specific labeling of proteins with lanthanide ions offers great opportunities for investigating the structure, function, and dynamics of proteins by virtue of the unique properties of lanthanides. Lanthanide‐tagged proteins can be studied by NMR, X‐ray, fluorescence, and EPR spectroscopy. However, the rigidity of a lanthanide tag in labeling of proteins plays a key role in the determination of protein structures and interactions. Pseudocontact shift (PCS) and paramagnetic relaxation enhancement (PRE) are valuable long‐range structure restraints in structural‐biology NMR spectroscopy. Generation of these paramagnetic restraints generally relies on site‐specific tagging of the target proteins with paramagnetic species. To avoid nonspecific interaction between the target protein and paramagnetic tag and achieve reliable paramagnetic effects, the rigidity, stability, and size of lanthanide tag is highly important in paramagnetic labeling of proteins. Here 4′‐mercapto‐2,2′: 6′,2′′‐terpyridine‐6,6′′‐dicarboxylic acid (4MTDA) is introduced as a a rigid paramagnetic and fluorescent tag which can be site‐specifically attached to a protein by formation of a disulfide bond. 4MTDA can be readily immobilized by coordination of the protein side chain to the lanthanide ion. Large PCSs and RDCs were observed for 4MTDA‐tagged proteins in complexes with paramagnetic lanthanide ions. At an excitation wavelength of 340 nm, the complex formed by protein–4MTDA and Tb³⁺ produces high fluorescence with the main emission at 545 nm. These interesting features of 4MTDA make it a very promising tag that can be exploited in NMR, fluorescence, and EPR spectroscopic studies on protein structure, interaction, and dynamics.