Metabolic profiling of Angelica acutiloba roots utilizing gas chromatography-time-of-flight-mass spectrometry for quality assessment based on cultivation area and cultivar via multivariate pattern recognition

Gas chromatography time-of-flight mass spectrometry was applied to elucidate the profiling of primary metabolites and to evaluate the differences between quality differences in Angelica acutiloba (or Yamato-toki) roots through the utilization of multivariate pattern recognition-principal component analysis (PCA). Twenty-two metabolites consisting of sugars, amino and organic acids were identified. PCA analysis successfully discriminated the good, the moderate and the bad quality Yamato-toki roots in accordance to their cultivation areas. The results signified two reducing sugars, fructose and glucose being the most accumulated in the bad quality, whereas higher quantity of phosphoric acid, proline, malic acid and citric acid were found in the good and the moderate quality toki roots. PCA was also effective in discriminating samples derive from different cultivars. Yamato-toki roots with the moderate quality were compared by means of PCA, and the results illustrated good discrimination which was influenced most by malic acid. Overall, this study demonstrated that metabolomics technique is accurate and efficient in determining the quality differences in Yamato-toki roots, and has a potential to be a superior and suitable method to assess the quality of this medicinal plant.     

Effect of lanthanum substitution on microstructure and electrical properties of (Bi0.5Na0.5)1−1.5xLaxTi0.41Zr0.59O3 ceramics

Bismuth sodium zirconate (BNZ) based ceramics with a composition of (Bi_0.5Na_0.5)_1?1.5xLa_xTi_0.41Zr_0.59O₃ where x = 0, 0.005, 0.01, 0.02 and 0.03 were prepared by a solid-state mixed oxide method and sintered at the temperature of 900 °C for 2 h. All the samples had relative density between 91 and 97% of their theoretical values. Phase analysis using X-ray diffraction indicated single rhombohedral or pseudo-cubic perovskite structure. SEM showed that addition of La caused the average grain size of the BNTZ ceramics to decrease as well as an improvement of sample density. Dielectric properties at room temperature measured at 10 kHz indicated that addition of La increased the dielectric constant. The results of ferroelectric characterization also revealed that adding La caused a decrease in coercive field without affecting the remanent polarization.     

Effects of Nd and Co co-doping on phase,microstructure and ferromagnetic properties of bismuth ferrite ceramics

In this work, the samples of Bi_0.95Nd_0.05Co_xFe_1?xO₃ (BNFCO) with x=0, 0.03, 0.05 and 0.07 mol fraction, were prepared by a solid state reaction. The effect of Nd and Co co-doping concentration on phase, densification, microstructure and ferromagnetic properties were examined. The BNFCO powders were prepared using a mixed-oxide method and calcined at 800 °C for 2 h before being pressed and sintered at various temperatures in the range of 825–900 °C for 2 h. An increase in Co co-doping content increased density of the ceramics. Phase analysis by X-ray diffraction indicated the existence of rhombohedral phase for all BNFCO powders and ceramics. Microstructural investigation using the scanning electron microscope showed a reduction of grain size with increasing Co content. Magnetic hysteresis loops showed that remanent magnetization and coercive magnetic field of the Co-doped samples were improved.     

Effects of CuO nanoparticles addition on properties of PMNT ceramics

This research investigates the role of CuO nanoparticles addition on properties of 0.9PMN–0.1PT (PMNT) ceramics. Phase purity, density, microstructure, dielectric and ferroelectric properties of the ceramics were investigated. The density of the ceramics reaches a maximum when 0.5 wt% of CuO is added into the ceramics while grain size of the ceramics tends to increase with the increase in CuO content. ε_max of the ceramics tends to increase with increasing CuO concentration. The improvement of P_r of the ceramics is observed in the ceramic incorporated with over 0.1 wt% of CuO.     

High- and low-field dielectric responses and ferroelectric properties of (Bi0.5Na0.5)Zr1−xTixO3 ceramics

Bismuth sodium zirconate titanate (Bi_0.5Na_0.5)Zr_1?xTi_xO₃ with (x=0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) ceramics was fabricated by a conventional sintering technique at 850–1000 °C for 2 h. From X-ray diffraction study, three regions of different phases were observed in the ceramic system; i.e., orthorhombic phase region (0≤x≤0.2), mixed-phase region (0.3≤x≤0.4), and rhombohedral phase region (0.5≤x≤0.6). It was observed that the phase evolution from orthorhombic to rhombohedral symmetry resulted in a noticeable increase of the dielectric properties. The results from the high- and low-field dielectric responses indicated that the dielectric properties of both BNZ and BNZT ceramics were dominantly attributed to the reversible contribution. It was also noticed that grain size showed only partial influence on the increase of low-field dielectric constant in Ti-rich BNZT ceramic.     

The effect of morphotropic phase boundary on dielectric properties of Bi0.5Na0.5Ti1−xZrxO3 solid solutions

Lead-free bismuth sodium titanate zirconate (Bi_0.5Na_0.5Ti_1?xZr_xO₃ or BNTZ) solid solutions with varied composition of x=0.50, 0.55, 0.58, 0.60, 0.63, 0.65, 0.68, 0.70, 0.73, 0.75 and 0.78 mol fraction were obtained using a conventional mixed-oxide method. XRD analysis indicated that the increase in concentration of Zr led to compositions across morphotropic phase boundary region. A quantitative structural investigation was carried out using the X-ray powder diffraction data. The rhombohedral phase was found to dominate for x<0.68 with space group R3c. In the morphotropic phase boundary (MPB) region i.e. 0.68≤x≤0.75, it was demonstrated that coexistence of rhombohedral and orthorhombic phase was observed. For x=0.78, the phase was completely orthorhombic with space group Pmna. Furthermore, the dielectric properties showed some enhanced activity of dipole movement at MPB boundaries which supported the presence of MPB region in this material system.     

Thermal Expansion Behavior of (Bi0.5Na0.5)Zr1-x Ti x O3 Ceramics

(Bi_0.5Na_0.5)Zr_1-xTi_xO₃ with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 ceramics were fabricated by a conventional sintering technique at 850–950°C for 2 h. From X-ray diffraction study, three regions of different phases were observed in the ceramic system; i.e., orthorhombic phase region (0 ≤ x ≤ 0.2), mixed-phase region (0.3 ≤ x ≤ 0.4), and rhombohedral phase region (0.5 ≤ x ≤ 0.6). The thermal expansion coefficient data indicated the phase transition in the temperature range from 100°C–150°C of the ceramics. The thermal strain curve of all compositions suggested a decrease of local polarization with temperature increment up to the Burns temperature.     

Effects of dysprosium oxide addition in bismuth sodium titanate ceramics

This research focuses on the preparation and characterization of dysprosium-doped bismuth sodium titanate (BNT) ceramics. The compounds were prepared using the conventional mixed-oxide method. The amount of dysprosium oxide used was varied from 0 to 2 at.%. The mixed powders were calcined at 800 °C and checked for phase purity using X-ray diffraction technique. The powders were then cold-pressed into small pellets which were subsequently sintered at 1050 °C for 2 h. The results from density measurement and SEM micrographs showed that highly dense and high-purity ceramics were obtained. The grain size of Dy-doped samples was found to decrease with increasing Dy content. Compared to pure BNT, the addition of Dy₂O₃ in BNT ceramics slightly increased the dielectric constant values near room temperature. In addition, the Dy doping resulted in a more diffused transition temperature, less frequency dependence of the dielectric constant and very low values of the dielectric loss.     

Dielectric properties,electric-field-induced polarization and strain behavior of Lead Zirconate Titanate-Strontium bismuth Niobate ceramics

The dielectric properties and electric-field-induced polarization and strain behavior of (1-x)PZT-xSBN (x ranged from 0 to 1.0 weight fraction) ceramics prepared by a conventional mixed-oxide method were investigated. The dielectric properties indicated that the dielectric constant of PZT could be enhanced with small addition of SBN (x = 0.1). From the polarization hysteresis loop measurements, it was found that the ferroelectric properties of nominal PZT-SBN ceramics changed strongly from the normal ferroelectric in PZT-rich ceramics to the paraelectric character in SBN-rich compositions. The strain hysteresis loops of nominal PZT-SBN under bipolar electric field loading suggested that the butterfly curve was observed in some compositions (0 ≤ x ≤ 0.3 and pure SBN ceramic). This research clearly showed the significance of SBN in controlling the electrical properties of nominal PZT-SBN ceramics.     

Electrical and mechanical properties of ferroelectric lead zirconate titanate/tungsten oxide ceramics

Ferroelectric PZT/xWO₃ ceramics (when x = 0, 0.5, 1, 3 and 5 vol%) were fabricated from PZT and nano-sized WO₃ powders by a solid-state mixed-oxide method. Phase characterization suggested that the reaction between PZT and WO₃ occurred during the sintering. This reaction seemed more pronounced with increasing the content of WO₃. The maximum density at approximately 97% of the theoretical value was achieved at 1 vol% of WO₃ addition. The grain size was reduced with an addition of WO₃ particles from 7.8 μm for PZT to 1.8 μm for 0.5 vol% WO₃ and 0.8 μm for 1–5 vol% WO₃. Mechanical properties of PZT could be improved with an addition of WO₃ nano-particulates. The addition of 0.5 vol% WO₃ could maintain good electrical properties while increasing WO₃ significantly reduced dielectric and piezoelectric constants of the PZT.