Structual and Dielectric Properties of Pb(Zr0.53Ti0.47)O3 Thin Films Grown on LaNiO3 Buffered Si Substrates
Ferroelectric Pb(Zr0.53Ti0.47)O3 thin films with thickness of around 800 nm were prepared on LaNiO3 (LNO) buffered SiO2/Si substrates by sol-gel method. The LNO buffer layer serves as the bottom electrode and the template for growing PZT thin films with preferred orientation. The (110)-textured PZT thin films can be obtained on 250 nm-thick LNO buffered SiO2/Si substrates. Upon using the LNO buffer layer, the annealing temperature of the PZT films is lowered to 600degC. Our results indicate that PZT thin films prepared on LNO buffered Si substrates have good structural and dielectric properties for sensor and actuator applications.
Dielectric properties of lead zirconate titanate thin films deposited on metal foils
Ferroelectric lead zirconate titanate (PZT) thin films deposited on metal foil substrates are suitable for developing a wide range of applications. In this letter, we report on PZT films deposited on a variety of foils, including titanium, stainless steel, brass, and nickel alloys, using sol–gel processing. The dielectric properties were shown to depend strongly on the foil material. Excellent properties for capacitors, including high dielectric constant (e=400), low dielectric loss (loss tangent of <5%), and low leakage current (below 5×10−8 A at 5 V) were obtained on titanium and good results were also obtained on other foils, such as stainless steel and brass foils. Also, excellent high-frequency properties were observed for capacitors on titanium, stainless steel, and brass foils.
New Sweet-Tasting C21-Pregnane Glycosides from Pericarps of Myriopteron extensum.
Ten novel C21 pregnane glycosides, extensumside C-L (1-10), were isolated as highly sweet-tasting substances from the edible pericarps of Myriopteron extensum (Wight) K. Schum by sensory-guided fractionation and purification. Their structures were determined through 1D and 2D NMR, such as HSQC, HMBC, 1H-1H COSY, HSQC-TOCSY, and ROESY, as well as other spectroscopic analysis combined with chemical evidence. These compounds shared the same aglycone, 3β,16α-dihydroxy-pregn-5-en-20-one, and contained the deoxysugar chain and the glucose chain which were linked to C-3 and C-16 of the aglycone, respectively. The sweetness potency was evaluated by a human sensory panel test and preliminary structure-taste relationship was discussed. The sweetness intensities of these compounds are between 50 and 400 times greater than that of sucrose. Furthermore, quantitation analyses of compounds 1, 3, 4, and 6 in different parts of M. extensum indicated that the concentrations of these sweet components in the pericarps are obviously higher than those in stems and roots.