MWCNTs/hydroxypropyl cellulose/polyethylene glycol-based shape-stabilized phase change materials

Journal of Thermal Analysis and Calorimetry - Polyethylene glycol (PEG) is widely used as phase change materials (PCMs). However, the leakage and low thermal conductivity issues restrict its...     

An improved quasi-zero stiffness isolator with two pairs of oblique springs to increase isolation frequency band

Nonlinear Dynamics - Quasi-zero stiffness (QZS) isolators can achieve superior performance in vibration isolation; however, this superiority is often effective only for an excitation with the small...     

Improving the Mechanical Properties of Polycarbonate Nanocomposites with Plasma‐Modified Carbon Nanofibers

The mechanical properties of polycarbonate film embedded with carbon nanofibers were studied based on plasma surface modification of carbon nanofibers by the use of polystyrene. The nanofiber surfaces were modified by various processing conditions including plasma polymerization power, nanofiber concentration, and ultrasonication time. The tensile strength and Young's modulus of the carbon nanofiber‐polycarbonate composites were then measured. The mechanical behavior of the composite was found to be affected by dispersion of the nanofibers. Higher plasma power resulted in improved mechanical strength. A maximum strength (10% increase) was achieved at a low concentration (1 wt.%) of nanofibers. The optimization of ultrasonication time indicated that the maximum strength occurred at different times for the composites with different concentrations of the modified carbon nanofibers.     

卟啉化合物的研究(Ⅰ)——5-对羟苯基-10,15,20-三对甲氧苯基卟啉及其蒽醌衍生物的金属络合物的合成

近年来,在探索光合作用的奥密,有效利用太阳能的研究中,卟啉化合物的良好催化性能为各国科学工作者所关注^[1-3]。1978年Porter等用取代四苯基卟啉的锰络合物与醌组成分子间的氧化还原体系,在可见光照射下实现了放氧。     

Solving the constrained modified KP hierarchy by gauge transformations

In this paper, we mainly investigate two kinds of gauge transformations for the constrained modified KP hierarchy in Kupershmidt-Kiso version. The corresponding gauge transformations are required to keep not only the Lax equation but also the Lax operator. For this, by selecting the special generating eigenfunction and adjoint eigenfunction, the elementary gauge transformation operators of modified KP hierarchy T_D(Φ) = (Φ^?1)^?_x¹? Φ^?1 and T_I (Ψ) = Ψ^?1? ^?1Ψ_x, become the ones in the constrained case. Finally, the corresponding successive applications of T_D and T_I on the eigenfunction Φ and the adjoint eigenfunction Ψ are discussed.     

Bilinear Identities and Squared Eigenfunction Symmetries of the BCr-KP Hierarchy

The BC_r-KP hierarchy is an important sub hierarchy of the KP hierarchy, which includes the BKP and CKP hierarchies as the special cases. Some properties of the BC_r-KP hierarchy and its constrained case are investigated in this paper, including bilinear identities and squared eigenfunction symmetries. We firstly discuss the bilinear identities of the BC_r-KP hierarchy, and then generalize them into the constrained case. Next, we investigate the squared eigenfunction symmetries for the BC_r-KP hierarchy and its constrained case, and also the connections with the additional symmetries. It is found that the constrained BC_r-KP hierarchy can be defined by identifying the time flow with the squared eigenfunction symmetries.     

Differential Pulse Voltammetry Determination of Ofloxacin in Human Serum and Urine Based on a Novel Tryptophan‐graphene Oxide‐carbon Nanotube Electrochemical Sensor

The highly sensitive determination of ofloxacin (OFL) in human serum and urine was achieved on a novel tryptophan‐graphene oxide‐carbon nanotube (Trp‐GO‐CNT) composite modified glassy carbon electrode (Trp‐GO‐CNT/GCE). The Trp‐GO‐CNT composite was fabricated, and its morphologies and surface functional groups were characterized by field emission scanning electron microscopy (FE‐SEM) and Fourier transform infrared (FT‐IR) spectroscopy. The electrochemical properties of Trp‐GO‐CNT/GCE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The superior electrochemical behaviors of Trp‐GO‐CNT/GCE toward OFL can be mainly assigned to the excellent electrocatalytic activity of Trp, the great conductivity and high surface area of GO and CNT, and the synergistic effect between Trp, GO and CNT. Under optimum conditions, a wide and valuable linear range (0.01–100 μM), a low detection limit (0.001 μM, S/N=3), a good linear relationship (R2>0.999), good stability and repeatability were obtained for the quantitative determination of OFL. Furthermore, the Trp‐GO‐CNT electrochemical sensor was successfully applied to the determination of OFL in human serum and urine samples, and satisfactory accuracy and recovery could be obtained.     

Non-feedback precoder for optical DQPSK modulation

A novel non-feedback precoder circuit for high-speed parallel optical differential quadrature phase shift keying （DQPSK） modulation is proposed. The alternative control signal is introduced in replacement of the conventional feedback one, which eliminates the speed limitation due to the electronic propagation delay. The proposed precoder consists of four differential encoders, an exclusive OR gate, a cross switch, and delay lines. It is demonstrated by a true pseudo random bit sequence （PRBS） transmission at 20 Gb/s.