Energy harvesting using multilayer structure based on 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 single crystal

In this paper we fabricated the multilayer structure used as the resonance-based vibration energy-harvesting device based on 0.71Pb(Mg_1/3Nb_2/3)O₃–0.29PbTiO₃ single crystal. The performances of the device including the output voltage and power were studied systematically. Under a cyclic force of 4 N (peak value), a high output power of 4.94 mW and a corresponding peak voltage of 3.14 V were measured at 1.4 kHz with a matching load resistance of 1.0 kΩ. The results demonstrate the potential of the device in energy-harvesting applied to low-power portable electronics and wireless sensors.     

Simultaneous Determination of Escin Ia and Its Isomer Isoescin Ia by LC�CMS�CMS: Application to a Pharmacokinetic Study of Escin Ia in Rats

A rapid and sensitive LC?CMS?CMS method for the simultaneous determination of escin Ia and isoescin Ia in rat plasma, urine, feces and bile samples was developed and validated. Analytes and telmisartan [internal standard (IS)] were extracted by solid-phase extraction on C₁₈ cartridges. Components in the extract were separated on an HC-C₁₈ column (5 ??m, 150 × 4.6 mm i.d.) using 10 mM ammonium acetate?Cmethanol?Cacetonitrile (40:30:30, v/v/v) as the mobile phase. The method demonstrated good linearity from 5 ng mL^?1 (LLOQ) to 1,500 ng mL^?1 for both escin Ia and isoescin Ia. Intra- and inter-day precision measured as RSD was within ±15%. Recoveries and matrix effects of both escin Ia and isoescin Ia were satisfactory in all four matrices examined. The method was successfully applied to a pharmacokinetic study in Wistar rats after a single intravenous administration of escin Ia at the dose of 1.0 mg kg^?1.     

Constructions of p-ary Quadratic Bent Functions

Bent functions have many applications in the fields of coding theory, communications and cryptography. This paper studies the constructions of bent functions having the form for odd n and for even n, over the finite field of odd characteristic p, where . Based on the irreducibility of some polynomials on , we focus on characterizing the bent functions for n=p ^v q ^r and n=2p ^v q ^r , where is an odd prime and p a primitive root modulo q ². Moreover, the enumerations of those functions are also considered. Partially supported by the NSF of China under Grants No. 60603012 and No. 60573053.     

Orientation dependence of electrical properties of 0.96Na<Subscript>0.5</Subscript>Bi<Subscript>0.5</Subscript>TiO<Subscript>3</Subscript>-0.04BaTiO<Subscript>3</Subscript> lead-free piezoelectric single crystal

In this paper, a single crystal of 0.96Na_0.5Bi_0.5TiO₃-0.04BaTiO₃ with dimensions of Φ 30×10 mm was grown by the top-seeded-solution growth method. X-ray powder diffraction results show that the as-grown crystal possesses the rhombohedral perovskite-type structure. The dielectric, piezoelectric and electrical conductivity properties were systematically investigated with 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples. The room-temperature dielectric constants for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples are found to be 650, 740 and 400 at 1 kHz. The (T _m, ε _m) values of the dielectric temperature spectra are almost independent of the crystal orientations; they are (306°C, 3718), (305°C, 3613) and (307°C, 3600) at 1 kHz for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal. The optimum poling conditions were obtained by investigating the piezoelectric constants d ₃₃ as a function of poling temperature and poling electric field. For the 〈001〉 and 〈110〉 crystal samples, the maximum d ₃₃ values of 146 and 117 pC/N are obtained when a poling electric field of 3.5 kV/mm and a poling temperature of 80°C were applied during the poling process. The as-grown 0.96Na_0.5Bi_0.5TiO₃-0.04BaTiO₃ crystal possesses a relatively large dc electrical conductivity, especially at higher temperature, having a value of 1.98×10⁻¹¹ Ω⁻¹⋅m⁻¹ and 3.95×10⁻⁹ Ω⁻¹⋅m⁻¹ at 25°C and 150°C for the 〈001〉 oriented crystal sample.     

Ferroelectric phase transitions of the 0.32PIN-0.345PMN-0.335PT single crystals studied by temperature-dependent Raman spectroscopy,dielectric and ferroelectric performance

The ferroelectric phase transition characteristics of the 0.32Pb(In_1/2Nb_1/2)O₃-0.345Pb(Mg_1/3Nb_2/3)O₃-0.335PbTiO₃ (0.32PIN-0.345PMN-0.335PT) single crystals were studied by the temperature-dependent Raman spectroscopy and some electrical properties. Ferroelectric monoclinic phase was confirmed at room temperature by the numbers of the Raman modes. Successive ferroelectric phase transitions, i.e. ferroelectric monoclinic phase to ferroelectric tetragonal phase transition (FE_M-FE_T) and ferroelectric tetragonal phase to paraelectric cubic phase transition (FE_T-P_C), are evidenced by the anomalies of Raman modes line width, peaks intensity and their ratios around T_M-T and T_C/T_m temperatures. The temperature dependent permittivity derivative ξ = d?/dT not only provides further evidence of the successive ferroelectric phase transitions, but also demonstrates the second-order transition characteristic of the FE_M-FE_T phase transition and the first-order transition feature of the FE_T-P_C phase transition. The FE_M-FE_T phase transition is also confirmed by the abnormal narrowing of the P-E loops, decrease of the P_r and E_c values, and extremums of the pyroelectric performance.     

TEMPO‐Mediated Oxidation of Primary Alcohols to Aldehydes under Visible Light and Air

A homogeneous visible light photoredox TEMPO‐mediated selective oxidation of primary alcohols to the corresponding carbonyl compounds was developed using molecular oxygen from air as the terminal oxidant. Ru(bpy)₃(PF₆)₂ (bpy: bipyridyl) and Ir(dtb‐bpy)(ppy)₂(PF₆) (dtb‐bpy: 4,4′‐di‐tert‐butyl‐2,2′‐bipyridyl; ppy: 2‐phenylpyridine) were used as the sensitizers.